What Are The Four Stages of Mesothelioma Cancer?

One rare form of cancer is called Mesothelioma, a malignant tumor in the mesothelial tissues of the lungs and the abdomen, arising from the inhalation of asbestos. Its rarity is one of the reasons why a lot of people are not aware of this kind of fatal disease. In fact, many people die of Mesothelioma undiagnosed. Although there is now a growing awareness of the hazards of asbestos to health, still many have not heard of Mesothelioma and thus, have not understood its nature, cause, signs and treatment. Even some physicians find it hard to detect Mesothelioma because its symptoms are akin to other diseases like lung cancer and pneumonia. Furthermore, it takes decades for a patient who was exposed to asbestos to develop Mesothelioma -- fifty years, at most.

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Being unaware of Mesothelioma poses higher risks since it deters diagnosis and treatment. A person undergoing treatment must know the different stages of the cancer or the extent of the disease. Chances of recovering from Mesothelioma and the kind of treatment depend on the stage of the illness. There are basically two staging systems used for Pleural Mesothelioma (lungs): TNM system and Brighan system. These staging systems are also used in other kinds of cancers; however, the first is commonly used. There is no established method in determining the stage of the Peritoneal Mesothelioma cancer (abdominal) so the TNM system is used.

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There are three variables in the TNM system: tumor, lymph nodes and metastasis. In the earliest stage of Mesothelioma, stage I, the malignant Mesothelioma cells start to grow and multiply only one layer of the pleura. The pleura is the membrane that encloses the lungs and lines the wall of the chest cavity. However, there are some instances wherein the pericardium (membrane that covers the heart) and diaphragm cover are already affected. In this case, the cancer patient is still in stage I Mesothelioma.

In the second stage, the two layers of the pleura are already affected by Mesothelioma. Take note, however, that in this stage, only one side of the body is affected. Normally, the pleura produces only small amount of lubricating fluid that allows easy expanding and contracting of the lungs. The excess fluid is absorbed by the blood and the lymph vessels so there's a balance between the amount of fluid produced and removed. During the second stage Mesothelioma, fluid starts to build up between the membrane of the lungs and the membrane of the chest wall, resulting to pleural effusion. The increase in the volume of fluid produced causes shortness of breath and chest pain. Other Mesothelioma cancer patients experience dry and persistent cough. Diagnosis of the pleural effusion is achieved through a chest x-ray.

Stage III Mesothelioma means that the malignant cells have already spread to the chest wall, esophagus and the lymph nodes on one part of the chest. The patient may suffer severe pain near the parts affected. When not treated immediately or when the Mesothelioma patient doesn't respond well to medication, the cancer may advance to the fourth stage. The fourth stage Mesothelioma is formidable since at this stage the Mesothelioma cells have penetrated into the bloodstream and other organs in the body like the liver, the bones and the brain. The lymph nodes on the other side of the chest may also be affected by Mesothelioma in stage IV.

Brighan staging system, on the other hand, determines whether the Mesothelioma can be surgically removed or not and whether the lymph nodes are affected or not. In stage I Mesothelioma, the lymph nodes are not yet affected and the patient can still recover through surgery. In stage II, surgery can still be executed but some lymph nodes have already been infiltrated by the cancer cells. In stage III, the heart and chest wall are already affected; thus, surgery is no longer advisable. The lymph nodes in this stage, however, may or may not be affected. In the final stage, stage IV Mesothelioma, cancer cells have already gone to the bloodstream and other parts of the body like the heart, brain, bone and liver. In most cases, a patient who has reached stage IV Mesothelioma only has four to twenty-four months to live.

What Are The Four Stages of Mesothelioma Cancer?

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The Tile Shower Pan Liner Membrane - Tips For Success

The shower pan liner membrane is usually a vinyl sheet that's installed in the mortar base of the shower. All kinds of liners have been tried in the past, including liners of steel, iron, copper, lead and even tar. None of these materials were completely satisfactory. The currently used liner sheets seem to be the best solution yet.

membrane air dryer

Don't even think about building a masonry tile shower without a liner membrane. Why not? Well, you see, a shower floor is not waterproof. Water seeps right into the grout of the floor and then down into the shower base. The only thing that keeps the shower leak-proof is the liner layer. It's made to catch all the water that seeps into the floor and route it to special drain holes built into the floor.

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Here's what you get for the liner...

The actual liner sheet is made of either chlorinated polyethylene (CPE) or polyvinyl chloride (PVC). Either material works. The CPE is more flexible and seems to stay soft better, but it's more expensive and harder to find. Most installers use PVC liners and they seem to work perfectly, even if they are a little harder to fold and bend.

Here's how the liner, PVC or CPE, fits in the floor...

The PVC liner is installed between two mortar layers. The bottom mortar layer is sloped and that's what supports the liner sheet and guarantees that the water moves right to the drain. The liner is run up the wall to produce a water proof layer higher than the water could pool in the shower.

The real key to a leak-proof shower is getting the right shower pan liner membrane and getting it installed properly. Installation is not complicated. There are just a few tricks to make it a sure success.

The Tile Shower Pan Liner Membrane - Tips For Success

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Common Field Failures for Polymer Thick Film Membrane Switches

Membrane switches offer a reliable economical, cosmetically appealing answer for electronic switching applications. They provide a normally open, momentarily closed switch system. Used in a wide variety of applications, they can meet stringent requirements for shock and vibration; water, UV and chemical resistance and longevity. With proper design and choice of materials, membrane switches can provide the performance and durability necessary for the most demanding applications.

membrane keypad

The following discussion covers common failure points that can be mitigated, avoided or eliminated with proper design and materials selection.

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Silver Migration: Silver migration problems will be greatest in applications where moisture, heat and humidity are in prevalent. Silver migration is the ionic movement of silver between two adjacent traces where a voltage potential exists. Over time, silver migration can cause an electric short. Silver migration is commonly enabled by moisture. There are several methods to mitigate silver migration, including adhesive sealing, full perimeter gasketing and other design barriers. The mechanical configuration, bond to the device enclosure and connecting hardware can all contribute to sealing failures.

Dielectric Cross-over's, Jumpers or Bridges: When OEM requirements call for dense circuit layouts to meet the need for a high number of switches in a limited X-Y dimension, most membrane switch manufacturers use printed cross-overs, jumpers or bridges (all referring to a similar method). In its simplest manifestation, a silver trace is printed first, followed by a printed dielectric material, and finished with another printed silver trace over the dielectric. The dielectric insulating layer is the weak point in this construction. Because of the inherent properties of the material and application methods, a common failure is micro shorts that occur between the two overlapping traces as the silver leaches through the porous dielectric. While there are manufacturing and test methods to help mitigate this issue, the best way to avoid this failure is to avoid cross-over or jumpers altogether. Some membrane switch manufacturers can provide a double sided circuit where a layer of polyester provides insulation and completely eliminates the risk.

Graphic Overlay: The graphic overlay gets a surprising amount of stress in areas where switch contacts are made. Improper selection of the overlay materials can result in cracking and delaminating graphic layers. This cracking can occur in just a few hundred actuations. While initially manifesting itself as a "cosmetic issue" it can progress to the point of functionally failing non-tactile switch closure.

Collapsed Switches: A non-tactile membrane switch connection is made when a finger or probe pushes a shorting element against a nested finger circuit layer to momentarily close the circuit. The contact surfaces are often only separated by a few thousandths of an inch. Variations in temperature, air pressure or even multiple actuations can cause air to escape from the contact chambers which create a pressure differential leading to collapsed switches. A proper membrane switch design will mitigate this issue. Sealing, tactile domes and venting are a few methods commonly used to prevent collapsed switches.

Plastic domes can collapse due to extreme operating temperatures (high and low) and should be limited to applications in controlled environments. The actuation force is also influenced by temperature, with high temps producing very low actuation force and operator feedback, and low temperature actuation forces producing high actuation force and a "crunch" sound and feeling to the operator. Design parameters for plastic domes are critical to their performance and durability. There is no recovery for a collapsed plastic dome once its geometry is compromised.

Common causes of collapsed metal domes include, but are not limited to the following. If a metal dome is supported by a plastic injection molded enclosure surface, there can be variances in flatness or even pockets or cups that do not support one or more legs of the metal dome. Another manifestation of an irregular base surface is if the metal dome is placed into the membrane switch assembly with one or more legs supported on top of the adhesive spacer layer. Each of these cases cause premature dome failures. Furthermore, care should be taken to choose a metal dome manufacturer with a history of consistently acceptable production processes and choice of materials.

Cracked traces: It is very common for the dielectric substrate to bend, fold or be twisted as part of the assembly process. Polymer thick film traces printed on the substrate are subject to cracking when repeatedly bent or sharply creased on the outside radius. Proper design with good material selection and trace lay out can eliminate most causes of cracked traces. Manufacturers of double sided polymer circuitry have the best solution by placing circuit tail traces on the back or inside radius of the circuit tail and eliminating cross-overs, bridges, jumpers, etc. which can be fraught with cracked traces from printed stack ups over dielectric and conductive circuit traces.

Poor Tactile Life: Tactile feedback switches, if properly designed and manufactured can last millions of cycles. But improper design, material selection or poor manufacturing methods can create switches that lose their tactile response in a short period of time. Contact pad damage, corrosion, poor ventilation, material incompatibility and poor fabrication methods are some of the common causes for poor tactile life.

Creating a robust membrane switch requires an experienced manufacturer who has expertise in materials, reliability, design and robust manufacturing methods. Each and every new custom design should be thoroughly tested before launching into production. Make sure that the membrane switch manufacturer you select has the experience and technology to handle your requirements.

Common Field Failures for Polymer Thick Film Membrane Switches

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Why Use a Water Purifier and Reverse Osmosis Membrane

Are you aware of the fact that half of the world's hospitalization are due to water related diseases? It is but a heart weakening fact that over 1.4 million deaths of children occur every year due to consumption of unpurified water; in almost every 20 seconds a child dies! One of the dreaded diseases that cause death among children under the age of five globally is diarrhea. Records substantiate the fact that one in five child deaths are due to diarrhea, killing more children than malaria, measles, and AIDS combined. Why take risks or cause danger to your child's and your other family members' health when water purifier solutions are available in the market. If you are still drinking water directly from the tap or any other water source, get a water purification system installed right away. A series of the latest water purifier is available at organized retail outlets and also right at the comfort of your home. Choose a reliable brand and go for it.

kerdi membrane

It is a worrisome affair too if you are using a conventional water purification system. This is because such a system cannot effectively remove new age contaminants, micro organisms, and other dissolved particles. It is never too late. Switch your system now.

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Using the right purifier in sync with the water type also matters. It is after getting your water tested that you will know which mechanism you need. If you are recommended to use a reverse osmosis water purification system, there are numerous factors that need to be considered. First is choosing a reliable brand, one that has maintained a rapport for delivering superlative hi-tech systems for years together. Another is taking into account the RO membrane incorporated in the reverse osmosis water purification system. Generally, there are two common types of household RO membranes used - Cellulose Triacetate (CTA) membrane and Thin Film Composite (TFC or TFM) membrane.

The water you receive from your tap may be full of micro organisms, chlorine, and other contaminants. Though both the reverse osmosis membranes effectively purify the water, there is yet a difference between them. This difference is related to chlorine tolerance and filtration ability. The CTA membrane though chlorine tolerant, is more vulnerable to fouling from micro organisms. TFC/TFM membrane is less susceptible to organic fouling and rejects 98% of standard contaminants on an average.

Why Use a Water Purifier and Reverse Osmosis Membrane

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Reverse Osmosis - FAQ

Reverse osmosis water may offer the best combination of cost and quality. However there are several factors to consider if you think reverse osmosis may work for you.

waterproof membrane

How Does It Work?

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It's a simple concept based on some serious technology. Water pressure forces water through a very fine mesh filter membrane. Many pollutants can't make it through the filter and are thus excluded from the finished product.

Does It Take Out Minerals?

It gets out virtually all minerals plus many other problems too. Usually included in the finished system are sediment filters plus carbon filters too. That takes care of most chemicals, even drugs, toxic metals, and most microorganisms.

What About Taste?

The basic reverse osmosis membrane won't take out what usually affects taste or odors. For those problems, an included carbon filter solves those issues. Carbon improves taste and eliminates objectionable odors too. Carbon filtration usually comes in easily changed cartridge form.

Is The Finished Product Expensive?

Membranes last a really long time. Especially with sediment pre-filters to keep out the particles like iron and manganese, the main membrane will rarely need changing. Other filters including carbon cartridges will require changing more frequently. Other costs to consider with reverse osmosis are water waste costs. For every gallon of filtered material, 3 or more gallons of water are rejected and wasted. Not only is the waste not used, but it must be dealt with as waste too.

Can Anybody Use One?

Water pressure forces water through the filter. That means you must have about 35-40 psi pressure for a filter to work. That normally is no problem for a municipal system. For rural systems it may mean a booster pump must be added.

Reverse osmosis water excludes most kinds of pollution. It does involve some costs that you may not notice at first glance. Plus it works better with municipal water and waste systems instead of rural systems.

Reverse Osmosis - FAQ

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How to Install the Tile Shower Drain

The tile shower drain is tricky and much of the tricky part is buried in the shower pan. You see the whole shower pan is designed to route all the water to the drain. All the water includes the part that leaks right through the floor. That happens because tile floors are never waterproof. Some water ends up passing right through the floor.

membrane keyboard

The drain includes holes that are on two layers. The top layer you can easily see. The lower layer is down in the floor.

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Here's how it works.

Usually the drain is attached to the drain pipe so the drain base sits right on the subfloor. Then you build a very important layer. It's a sloped mortar layer that slopes at about 1/4 inch per foot from the base of the drain up on the shower walls.

Then over that sloped layer is installed the real trick to a shower floor. A waterproof sheet membrane is set over the sloped mortar and then attached right on top of the drain base. That liner is sealed to the base so the water that makes it to the liner is routed right to the lower drain holes.

After the liner is fitted in all the corners, which is tricky, the next layer is installed.

The next layer is another mortar layer that is the base for actually laying the floor tiles.

But wait...

Wouldn't the mortar stop up the lower drain holes? How could you have drain holes that are down inside a "solid" masonry floor?

How to Install the Tile Shower Drain

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Transdermal Drug Delivery, Transdermal Patches

Drug delivery technologies are now receiving considerable attention from pharmaceutical companies. The main purpose of developing alternative drug delivery technologies is to increase efficiency and safety of drug delivery and provide more convenience for the patient. Substantial research conducted during the past several years has lead to the development of technologies that meet the requisite criteria for delivering the drug through a non-invasive route. One of such technologies is transdermal drug delivery.

kerdi membrane

Transdermal drug delivery is the non-invasive delivery of medications from the surface of the skin - the largest and most accessible organ of the human body - through its layers, to the circulatory system. Medication delivery is carried out by a patch that is attached to the body surface. Transdermal patch is a medicated adhesive pad that is designed to release the active ingredient at a constant rate over a period of several hours to days after application to the skin. It is also called skin patch. A skin patch uses a special membrane to control the rate at which the drug contained within the patch can pass through the skin and into the bloodstream.

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The first transdermal patch was approved by the FDA in 1979. It was a patch for the treatment of motion sickness. In the mid-1980s, the pharmaceutical companies started the development of a nicotine patch to help smokers quit smoking, and within a few months at the end of 1991 and beginning of 1992 the FDA approved four nicotine patches.

Today drugs administered through skin patches include scopolamine (for motion sickness), estrogen (for menopause and to prevent osteoporosis after menopause), nitroglycerin (for angina), lidocaine to relieve the pain of shingles (herpes zoster). Non-medicated patches include thermal and cold patches, weight loss patches, nutrient patches, skin care patches (therapeutic and cosmetic), aroma patches, and patches that measure sunlight exposure.

Advantages and disadvantages of transdermal drug delivery

Transdermal drug delivery systems offer several important advantages over more traditional approaches, including:
longer duration of action resulting in a reduction in dosing frequency Increased convenience to administer drugs which would otherwise require frequent dosing improved bioavailability more uniform plasma levels reduced side effects and improved therapy due to maintenance of plasma levels up to the end of the dosing interval flexibility of terminating the drug administration by simply removing the patch from the skin Improved patient compliance and comfort via non-invasive, painless and simple application

Some of the greatest disadvantages to transdermal drug delivery are:

possibility that a local irritation at the site of application Erythema, itching, and local edema can be caused by the drug, the adhesive, or other excipients in the patch formulation
The main components of a transdermal patch are:

Transdermal patch may include the following components:

Liner - Protects the patch during storage. The liner is removed prior to use. Drug - Drug solution in direct contact with release liner Adhesive - Serves to adhere the components of the patch together along with adhering the patch to the skin Membrane - Controls the release of the drug from the reservoir and multi-layer patches Backing - Protects the patch from the outer environment
Types of transdermal patches

There are four main types of transdermal patches:

Single-layer Drug-in-Adhesive

In this system the drug is included directly within the skin-contacting adhesive. In this type of patch the adhesive layer is responsible for the releasing of the drug, and serves to adhere the various layers together, along with the entire system to the skin. The adhesive layer is surrounded by a temporary liner and a backing.

Multi-layer Drug-in-Adhesive

The Multi-layer Drug-in-Adhesive is similar to the Single-layer Drug-in-Adhesive in that the drug is incorporated directly into the adhesive. The multi-layer system adds another layer of drug-in-adhesive, usually separated by a membrane. This patch also has a temporary liner-layer and a permanent backing.

Reservoir

The Reservoir transdermal system design includes a liquid compartment containing a drug solution or suspension separated from the release liner by a semi-permeable membrane and adhesive. The adhesive component of the product can either be as a continuous layer between the membrane and the release liner or as a concentric configuration around the membrane.

Matrix

The Matrix system has a drug layer of a semisolid matrix containing a drug solution or suspension, which is in direct contact with the release liner. The adhesive layer in this patch surrounds the drug layer partially overlaying it.

The future of transdermal drug delivery

Transdermal drug delivery is theoretically ideal for many injected and orally delivered drugs, but many drugs cannot pass through the skin because of skin's low permeability. Pharmaceutical companies develop new adhesives, molecular absorption enhancers, and penetration enhancers that will enhance skin permeability and thus greatly expand the range of drugs that can be delivered transdermally.

Two of the better-known technologies that can help achieve significant skin permeation enhancement are iontophoresis and phonophoresis (sonophoresis). Iontophoresis involves passing a direct electrical current between two electrodes on the skin surface. Phonophoresis uses ultrasonic frequencies to help transfer high molecular weight drugs through the skin.

A newer and potentially more promising technology is micro needle-enhanced delivery. These systems use an array of tiny needle-like structures to open pores in the stratum corneum and facilitate drug transport. The structures are small enough that they do not reach the nerve endings, so there is no sensation of pain. These systems have been reported to greatly enhance (up to 100,000 fold) the permeation of macromolecules through skin.

Transdermal Drug Delivery, Transdermal Patches

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Soundproofing Your Fence

Building a soundproof or noise control fence is relatively easy. Soundproofing a redwood or cedar fence is always the best and those are the type of fences we will be talking about in this article.

membrane vacuum pump

If you are constructing a new fence, the first order of business would be to set the posts in concrete footers. Once the 4" X 4" posts are set in concrete then you would nail in the 2" X 4" cross members. Now you have a complete fence structure and you are ready to install the Mass loaded vinyl. Mass loaded vinyl is a high-grade vinyl that is impregnated with barium salts and silica to give it mass. The MLV comes in rolls and is generally 4' or 4 ½' wide on the roll. The weight of the MLV is either 1 Lb per sq ft or 2Lbs per sq ft.

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The vinyl would be stapled or nailed to the fence structure. It is best to use a plastic cap stapler for this application, but an in industrial stapler or nail gun would work. I recommend that that you install the MLV horizontally like a membrane across the fence structure. I always recommend over lapping the MLV wherever possible. The next step is very important, you will want to caulk all seams and all over lapped areas as well as caulking around the perimeter of the MLV membrane with acoustical caulking. This helps to seal all seams and maintains the STC value of the MLV at the seams and over lapped areas.

Once the MLV is attached and sealed, it is recommended that the fence slats be nailed up directly over top of the MLV membrane. This will help to protect the vinyl from the elements. For the aesthetic look many people will apply slats to both sides of the fence. This helps to protect the MLV for the weather and also gives the fence a refined look on both sides.

If you already have a sturdy redwood or cedar fence constructed, then it is just a matter of stapling up the MLV membrane to the existing fence and caulking all of the seams as well as the perimeter with the acoustical caulk. Once the MLV membrane is sealed, it is recommended that you once again slat over top of the MLV to protect it from the elements. The MLV is a weatherproof material, but anything over time and exposure will degrade, by adding slats to cover the MLV you protect it from the weather and it will last for many years to come.

Finally, some of my clients have used a combination of the MLV and a product called America mat closed cell foam on the inside of their noise control fences. The America mat adds sound absorption as well as sound blocking to the fence. The America mat will add to the cost of your fence but it will also help with the soundproofing.

For more information on a soundproof or noise control fence, call the experts at Soundproofing America Inc. Thanks for reading and learning about noise control fencing.
Soundproof Bob.

Soundproofing Your Fence

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Syphilis - A Bacterial Infection Called the Great Imitator

Syphilis or The Great Imitator is caused by a bacteria called Treponeum palladium. T. palladium belongs to a group of bacteria that are cork-screw shaped and are referred to as spirochetes. Other bacteria in this group cause Lyme disease, Relapsing fever and Leptospirosis. They all have a three phase life cycle like Syphilis.

waterproof membrane

Syphilis is acquired through contact with infected mucus membranes. Mucus membranes that can be infected on our body are the mouth and lips, vagina, penis and rectum. The eye can be infected also and for many years when syphilis was a bigger problem all newborns were treated with silver nitrate in each eye to prevent infection. Therefore, Syphilis can be acquired through unprotected oral, vaginal and rectal sex and during birth if the mother has an active infection.

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Syphilis can not be acquired through shaking hands, or from door knobs, swimming pools, shared clothing or toilet seats. To become infected your mucus membrane must contact an infected sore on another persons mucus membrane.

Because the mucus membrane ulcers are painless the infected individual can ignore them. A surprising number of people do just that. If the ulcers are left untreated they will resolve in 3-6 weeks. The incubation period from exposure until an ulcer appears is 10-90 days but three weeks is more common.

If the first or primary phase is not adequately treated, then a second phase will begin while the ulcers are healing or several weeks after they are healed. The second phase begins with a rash. The rash my be quite noticeable or very light but will appear on the palms and soles. Rashes on the palms and soles are rare and usually a tip to something unusual. In addition to rash, the second phase of Syphilis can be associated with fever, sore throat, swollen lymph nodes, and may appear to be another illness. Diffuse fungal infection can appear like this and often the infected person is carrying a skin fungus also. The picture can be confusing and if the person is not very honest about their sexual behavior can take some time and various tests to make a diagnosis.

Syphilis is diagnosed with a blood test called and RPR or and STS. It is very accurate. Treatment is by injectable antibiotics. Depending on the phase and duration of the infection this could be a single dose or multiple doses over a period of time.

Syphilis - A Bacterial Infection Called the Great Imitator

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Introduction to Disinfectants

A disinfectant is a chemical agent that is used to reduce the number of viable microorganisms on pharmaceutical surfaces to an acceptable level. Disinfectants have a variety of properties that include spectrum of activity, mode of action, and effectiveness. Some are bacteriostatic, where the ability of the bacterial population to reproduce is halted. In this case, the disinfectant can cause selective and reversible changes to microbial cells by interacting with nucleic acids and inhibiting enzymes, or permeating into the cell wall. Once the disinfectant is removed from contact with bacterial cells, the surviving bacterial population can potentially grow. Other disinfectants are bactericidal in that they destroy bacterial cells and cause irreversible damage through different mechanisms that include structural damage to the cell, cell lysis, and autolysis, resulting in leakage or coagulation of cytoplasm. The destruction of bacterial and fungal spores is a property which a given disinfectant may or may not possess. This type of chemical agent is called a sporicide. A chemical agent does not have to be sporicidal in order to be classified as a 'disinfectant' or as a 'biocide'. The bacteriostatic, bactericidal and sporicidal properties of a disinfectant is influenced by many variables.

membrane keypad

Disinfectants can be categorized into groups by chemical nature, spectrum of activity, or mode of action. Some disinfectants, on entering the microbial cell either by disruption of the membrane or through diffusion, proceed to act on intracellular components. Actions against the microbial cell include: acting on the cell wall, the cytoplasmic membrane (where the matrix of phospholipids and enzymes provide various targets) and the cytoplasm. This section provides a summary some of the more common disinfectants used the pharmaceutical environment. The two principle categories consist of non-oxidizing and oxidizing disinfectants.

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Non-Oxidizing Disinfectants: The majority of disinfectants in this group have a specific mode of action against microorganisms and generally have a lower spectrum of activity compared to oxidizing disinfectants. These disinfectants include alcohols. Alcohols have an antibacterial action against vegetative cells. The effectiveness of alcohols against vegetative bacteria increases with their molecular weight (i.e., ethanol is more effective than methanol and in turn isopropyl alcohols are more effective than ethanol). Alcohols, where efficacy is increased with the presence of water, act on the bacterial cell wall by making it permeable. This can result in cytoplasm leakage, denaturation of protein and eventual cell lysis (alcohols are one of the so called 'membrane disrupters'). The advantages of using alcohols include a relatively low cost, little odor and quick evaporation. However, alcohols have very poor action against bacterial and fungal spores and can only inhibit spore germination at best.

Oxidizing Disinfectants: This group of disinfectants generally has non-specific modes of action against microorganisms. They have a wider spectrum of activity than non-oxidizing disinfectants with most types able to damage bacterial endospores. The disinfectants in this group pose greater risks to human health. This group includes oxygen-releasing compounds like peracetic acid and hydrogen peroxide. They are often used in the gaseous phase as surface sterilants for equipment. These peroxygens function by disrupting the cell wall causing cytoplasm leakage and can denature bacterial cell enzymes through oxidation. Oxidizing agents are clear and colorless, thereby eliminating staining, but they do present significant health and safety concerns particularly in terms of causing respiratory difficulties to unprotected users.

This article is an edited version of:

Sandle, T. 'Selection and use of cleaning and disinfection agents in pharmaceutical manufacturing' in Hodges, N and Hanlon, G. (2003): 'Industrial Pharmaceutical Microbiology Standards and Controls', Euromed Communications, England.

Introduction to Disinfectants

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What Is a Membrane Sweep?

I have had personal experience with this, with both of my pregnancies I had a membrane sweep as I went past my due date by a few days for both. The first time I don't think it made much difference because I went into labour 4 days after and they say that if the membrane sweep is going to work you will probably go into labour within 48 hours. Now with my second child it definitely worked, I went into labour the next day.

membrane vacuum pump

I remember going for my ante-natal appointment to check my blood pressure as it had been high and she suggested that I had a membrane sweep. At this time I had no idea what this was and became very anxious about what was going to happen. The object of this article is to spread the word about what a membrane sweep is and what you should expect so that you will not feel so anxious about it when the time comes.

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Now a membrane sweep is actually a form of induction and is usually performed once you have reached 40 weeks of pregnancy although can be performed anytime from 38 weeks. It is performed by your midwife or doctor by placing a finger inside your cervix and making a circular 'sweeping' motion to try and seperate the membranes from the cervix, this will cause hormones to be released which in turn could start labour. This is performed to try and increase the chances of labour happening spontaneously without the need for any other form of induction. Whatever you do you must not try to perform this procedure yourself this must always be performed by a registered healthcare provider.

As the midwife/doctor is performing this procedure they will be able to tell if your cervix is favourable or not favourable, what I mean by that is, if your cervix is favourable it will be soft and already starting to open up a little from all those braxton hicks contractions you have been having. On my second visit I remember the midwife telling me that my cervix was already 1-2cm dilated, at that point I got very anxious as I knew 'it was time'.

This procedure does not hurt but does feel a little strange, after the procedure I felt some very low back ache and I had a little bleeding. Before you start to panic, this is normal and I went into labour the next day. Good luck.

What Is a Membrane Sweep?

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How the Sense of Hearing Works

The human ear is far more than an odd-shaped appendage that we hang our eyeglasses and earrings on. It's a complex system that changes sound waves into mechanical energy, then into fluid energy, and finally into electrical energy.

membrane keypad

The human ear is divided into three parts, which are known as the outer ear, the middle ear, and the inner ear. The outer ear is comprised of the auricle, which is the visible part, and the ear canal. Dividing the outer and middle ears is the tympanum, or tympanic membrane or eardrum. This is a delicate, tightly-stretched, pearly-gray membrane that vibrates when sound waves are delivered to it via the ear canal.

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The middle ear is the second section of the ear. It is a cavity that houses a chain of three tiny bones. These bones are called the malleus or "hammer," the incus or "anvil" and the stapes or "stirrup." These bones are named for objects that they resemble. The foot of the malleus rests on the eardrum, and it picks up the sound vibrations from the movements of the eardrum. The malleus is connected to the incus, which in turn is connected to the stapes. The foot of the stapes rests on a structure called the oval window. The stapes delivers sound to this window by moving in and out like a piston.

The third section of the human ear is the inner ear. It has parts designed for hearing and parts designed for balance. The cochlea, which is the part dedicated to hearing, is a structure that looks something like a snail's shell. The oval window mentioned above is situated in a wall of the cochlea. The cochlea is fluid-filled and contains a membrane that is attached to the hair-like nerve endings of the "hearing" nerve, or eighth cranial nerve.

But how does all this work? How do we hear, really?

The auricle and ear canal funnel sound waves toward the eardrum. The eardrum vibrates in response to the sounds, setting in motion the bones of the middle ear. As the foot of the third bone moves in and out of the oval window, the vibrations make waves in the fluid of the cochlea - something like dropping a stone in a still pond. The membrane inside the cochlea moves in response to these vibrations, stimulating the hair-like nerve endings. The nerve endings send the impulses to the brain for interpretation.

As you can see, the chain of systems for delivering sound information to the brain becomes more and more complex as it moves inward toward the brain.

There are many conditions that can reduce hearing. Some of these conditions prevent or disrupt sound waves from reaching the cochlea, causing what is called conductive hearing loss. Conditions that prevent or disrupt sound transmission in the inner ear and beyond it cause what are called neural or sensorineural hearing losses.

In future articles, learn how hearing aids and cochlear implants work and what results might be possible with these devices.

If you or someone you know has had a hearing loss, there are many resources available. For assistive equipment, technology devices, and deaf products, please click the link in my resource box.

How the Sense of Hearing Works

MEMBRANE

Shower Pan Membrane and the Shower Wall Covering

After the shower pan membrane is in place, then the wall boards go on the walls. That's the right order... the liner membrane and only then the wall boards. The best practice for building shower walls is using cement board. Here's how you do it...

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The liner membrane is installed right over a sloped mortar layer and then sealed to the base of the tile shower drain. Then the liner is run right up the wall against the studs. That gives you a waterproof liner that's up the walls several inches above the height of the curb. Only after the liner is in place do you install the boars for the wall.

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It is board too, as in cement boards. That's because cement boards won't rot and work well around water. Before the boards go on though, there's another important step.

Against the studs and before the wall boards, install a moisture barrier. That's either 15# roofing felt or 4 mil plastic sheet. That way the moisture that might get behind the cement boars is confined by that layer. Then you install the cement boards.

To build a wall properly, leave gaps between boards and then tape and mud the joints to produce a real sealed wall.

The other place to watch is the bottom of the cement boards. Install the boards so there is at least a 1/2 inch gap between the bottom of the cement board and the liner sheet itself? Why???

That gap is to reduce the chance of water wicking up into the cement board. Wet cement boards won't rot but they will mold. That's no good.

The shower pan membrane is the key to a tile shower that works properly. Getting the wall covering in the shower installed is the next step after the liner membrane is in place. With the materials available, it's easy to build a shower that keeps the water in the right place from the floor all the way up the walls.

There are other details that can make the shower walls last for a long time trouble-free...

Shower Pan Membrane and the Shower Wall Covering

MEMBRANE

The Pros and Cons of Reverse Osmosis Systems

Reverse osmosis systems is just one type of many water filtration systems that are available on the market today. Water filtration pushes water through a filter that traps contaminant molecules and releases pure water molecules. There are many health benefits that can be had from the use of water filtration systems including reverse osmosis systems.

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The first benefit is clean and safe water to drink, bathe, or cook in. Exposure to contaminants is greatly reduced or virtually eliminated. This results in fewer occurrences of diseases including cancer and skin irritations/disorders. With lead content being eliminated or reduced there will likely be many fewer occurrences of learning disabilities in children that currently occur at over 400,000 in the United States yearly. Skin and hair become softer and more properly hydrated.

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Osmosis is a process whereby a solution is pushed through a semi-permeable membrane with the lesser concentrated solution moving through the membrane to the greater concentration until the solutions become equalized. Reverse osmosis is where water is pushed through a semi-permeable membrane and pressure is applied to stop osmosis and then reverse it. It is a slow process and the result is pure water. The contaminants are trapped in the membrane which is an extremely fine membrane.

The pros of using reverse osmosis systems is that pure water will result. It is a popular seller. The same health benefits mentioned previously can result from using these systems. Although slow they are effective in removing contaminants.

The cons of using these systems lie in the fact that though they remove contaminants they also remove important minerals including magnesium, calcium, potassium, and many others. Depending on need and budget these systems will still be a good option for many consumers to consider for purchase.

The Pros and Cons of Reverse Osmosis Systems

MEMBRANE

How to Make a Shower Pan Using Mud and Not Much Money

Learning how to make a shower pan using mortar is the time=tested way to build a problem-free shower. The really tricky part about building shower pans is the best parts are hidden. The critical parts are buried in the shower floor and can't be seen after the shower is finished. Here are some of the basics that must be right.

waterproof membrane

1. The liner membrane.

MEMBRANE

Did you know that a shower floor naturally leaks. It's true. The tile grout and even some tiles are not waterproof at all. Water just passes right through the floor and that can cause major damage. The key to a shower pan that works is one layer. That's a waterproof layer that is actually built into the floor. That's usually a vinyl sheet that catches all the water that leaks into the floor.

2. Pre-sloped mortar.

That vinyl liner membrane is installed over a sloped layer of mortar. The slope throws the water toward a special shower drain. That means the water that makes it to the waterproof layer won't just pool within the shower floor and sit there. Without a slope below the liner, the shower base becomes a moldy mess.

3. Deck mud.

The mortar used to build the floor is often called deck mud. It's a special mix of parts, but it's a simple mix. It's just portland cement, sand and water. That's it. Those three ingredients in the right recipe are all you want.

4. Walls count too.

There' more than mortar too. See, the high moisture shower can ruin the walls behind the tile too. That's why usually cement board is the wall base of choice. That's because cement board won't rot. It's also important thought to put a waterproof layer behind the cement board. Otherwise, the walls can become damp and a moldy mess hidden out of sight.

5. The top mortar.

The second layer of mortar and the top layer of the shower pan is a final sheet of deck mud. This is actually laid right over the liner membrane. Ever thought about how the water that makes it to the liner membrane makes it to the drain? It seems like water wouldn't move through a solid masonry layer. That's where the special tile shower drain enters the picture.

If you want to learn how to make a shower pan, you must understand some of the hidden parts. The waterproof liner membrane and the special tile shower drain are really the keys to a leak-proof shower. Those are both buried in the floor and that's why it's hard to see how they work.

How to Make a Shower Pan Using Mud and Not Much Money

MEMBRANE

Reverse Osmosis - The World's Most Popular Drinking Water System

REVERSE OSMOSIS

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The most popular water purification process on the market today, is Reverse Osmosis. This water purification process was pioneered in the early 1950s  in response to the increasing incidence of kidney disease. RO was designed to replace the filtration function of the kidney, and is still used in the dialysis units of hospitals for this purpose today.

MEMBRANE

Reverse Osmosis utilizes the properties of a membrane to prevent the passage of particles through the membrane. Any particle larger than a water molecule is prevented from passing through the membrane, while the H2O is permitted to flow through to the "pure water" side. Because of the incredibly small pores which the water passes through, pre- filtration is necessary to prevent the plugging up of the membrane pores. Pre-filtration can combine 1, 2 or even 3 pre-filters. These pre-filters are combined to remove larger particles, chlorine, and even some chemicals and pesticides, before the water is subjected to the membrane purification technology. The number and type of pre-filtration depends on the water quality and impurities which are determined to be present in the water. Common pre-filtration includes, sediment filtration, chlorine removal, and chemical absorbent. The purpose of the pre-filtration is to protect and give longer life to the expensive membrane portion of the system.

SEDIMENT is first removed by a 20 micron filter. This filter may be constructed of tight wound cotton string spun around a spool, or it may be a pleated paper filter. By the way, this dot, "." is approximately 50 microns in size. Therefore a 20 micron filter would remove any substance which is half the size of a dot such as this one ". " Sediment, might include particles released from the inside of the pipes which deliver the water to your home, iron which has come out of solution and is now visible in your water as color, or just debris from the water source where your water is drawn from.

GRANULAR ACTIVATED CARBON (GAC) is most often used as the second filter, if the water source is chlorinated, as most municipal water is. Chlorine will destroy the Composite RO membrane quickly, so the chlorine must be removed before the water reaches the RO membrane. GAC filters are simple filters which are filled with small grains of carbon which are highly absorbent and effectively remove chlorine. When the water source does not contain chlorine, the GAC is usually replaced with a sediment filter of perhaps 10 microns of effective filtration, although some GAC filters can act as both a taste and odor filter, as well as a 10 micron sediment filter. It should be noted though, that because a GAC filter does not give "absolute" filtration results for sediment, the water treatment technologist who is applying the application for water treatment should be aware of what objective is to be attained. Is the objective tighter filtration after the 20 micron by placement of a 10 micron filter, or is ithe objective taste and odor removal, such as the rotten egg smell of hydrogen sulfide (H2S)? A GAC will reduce H2S levels where as a pleated or string sediment filter will not.

CARBON BLOCK filters are usually placed as the third pre-filter in a RO filter system. Carbon block filters have the potential to filter down as small as one-half micron. This is very small. As well, carbon blocks are reasonably effective at removing most chemicals and pesticides from the water. The effect of placing the pre-filters in this arrangement contributes to both the increased life expectancy of the RO membrane, as well as reduced pre- filter maintenance. The least expensive of the filters, the 20 micron, takes out the bulky larger substances. The next filter in expense, the GAC, takes out the chlorine and more particles which the 20 micron could not capture, and the most expensive of the pre-filters, the Carbon Block, is left to just absorb the chemicals.

THE MEMBRANE is the heart of the Reverse Osmosis System. As the water is forced through the membrane by water pressure, the impurities are held back and flushed out of the system through the brine water drain line. The membrane is capable of removing upwards of 95% of all impurities, if sufficient feed water pressure is available. Higher feed water pressure increases the efficiency of the membrane. Absolute minimum feed water pressure is 40 psi. If the pressure is not high enough an electric pressure booster pump must be added before the system. 

After the purified water has passed through the RO membrane, it is stored in a small storage tank, waiting to be delivered through a dedicated tap, to the consumer. The tank only holds about 6-8 liters of water at a time. This small tank is designed to fit under the kitchen sink for convenience. Larger tanks can be ordered and easily installed for consumers who desire more water available at a moments notice. It generally takes about 2 hours to fill an empty 8 liter tank. Most RO systems deliver from 35-75 gallons (160-340 liters) every 24 hours, depending on the membrane capacity which came with the RO system, and depending on the water pressure. (more pressure = more purified water)

Finally, on some systems the water may pass through a final carbon filter which is installed in the delivery line between the tank and the faucet, just as a final polish for good tasting water.

CRITICISM is often voiced about RO units because for every liter of purified water, 2-3 liters of brine water are discharged to the drain, to clean the impurities out of the water. This is true. However, this water is not gone! It is simply sent back out to where it came from, the water table. Nothing has been added to the water. The impurities it picked up as it passed through the ground, is returned to the ground.

CONCLUSION: Reverse Osmosis is the number one choice of consumers around the world who wish to provide pure, safe, good tasting drinking water for themselves and their families.                                              

Reverse Osmosis - The World's Most Popular Drinking Water System

MEMBRANE

Best Methods of Damp Proofing a Building Depending on Construction

Damp proofing of both domestic and commercial structures, although not the most glamorous aspect of a construction project, is still a vital part of the build process to get right. New build properties will, unless there has been a negligent moment by a contractor or architect, will have a physical isolation membrane around 150mm above external ground level (a damp proof course or DPC). This acts to prevent capillary movement of moisture rising higher than the barrier and effectively damp proofs the property above this barrier. So if the building has no earth bridging above the DPC and no leaking pipes, gutters or flashing, then you should have no problems in terms of damp proofing. It's all relatively straight forward.

membrane vacuum pump

Physical membranes as a vertical separation layer or DPC construction has been a standard in all brick and blockwork construction for well over 50 years. Older properties or properties built out of stone or rubble have significant challenges when it comes to damp proofing and there are limitations in terms of what can be achieved when looking at insertion of a DPC.

MEMBRANE

Let's first look at how we can damp proof a stone or random rubble wall property. This form of construction will not have a DPC so one possibility is to have a chemical DPC inserted into the build to isolate the internal property from the affects of rising dampness. This insertion into stone or non uniform walls is extremely difficult to apply and even more difficult to guarantee that you're getting it right. For these kind of chemical products to be effective damp proofing, they need to form a uniform layer of cream or liquid which will stop the passage of water vapour moving into the wall above. There are companies out there that will "guarantee" a chemical DPC in a stone or random wall construction but be wary! I would be asking the question "How can you test that the system installed is going to work?" It just isn't possible!

The principle of putting in a membrane is still the best way forward. The advantages of using a physical membrane such as the Newlath 2000 type dimpled sheet product which you can mechanically fix to the damp stone and then apply a finish over like render or plaster is a fail safe way of dealing with dampness no matter where it is coming from. These sheet dimpled membranes create an air gap and allow the walls to "dry out" over time which they will do if there is a heating system in the property. Any staining from salts which will be coming out of the structure will be isolated as well and will not be able to affect internal finishes. There really is no comparison with these products in stone structures. The membrane requires no surface preparation so if the building is listed it is "reversible". Therefore you will have no problems there and it just takes all the guess work out of the damp proofing process.

When you're dealing with brick built properties a chemical DPC is more likely to work in the way it was designed to. As you have a mortar bed in a uniform formation the cream products or liquids can form a barrier across the mortar bed just like a physical DPC and stop the capillary movement of water "wicking" up the walls damaging internal finishes. This form of damp proofing still has its challenges. Once you have drilled and injected the cream a re-rendering process needs to occur with a salt retardant additive to stop any salts coming through the render and damaging finishes. This can cause problems by moving salts and contaminants higher than the level of the treated damp proofing. Once again the simplicity of the mechanically fixed dimpled membrane covers all bases here. Once the membrane is installed the contractor can even dot and dab and skim on top, which means no lengthy drying out times so you can get in and decorate within a couple of days. The other approach can take weeks and weeks.

Best Methods of Damp Proofing a Building Depending on Construction

MEMBRANE

Reverse Osmosis

Reverse osmosis is something that sounds as if it is right out of the science books in a local high school. While many of the less scientific people of this world never stop to think about the process of reverse osmosis, it is a very real entity of our daily lives through the process of water filtering.

membrane potentiometer

When two volumes of liquid (in this case, water) or other solvents part ways by a membrane called a semi-permeable membrane, the liquid will naturally flow from the side of the low solute concentration to the side of the higher one. The way the flow is stopped with guaranteed success is when the side of the higher solute concentration is experiencing some level of exterior pressure. The external pressure then cause something that is then considered to be going through the process of reverse osmosis.

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Osmotic pressure is something that occurs only when one side of the system containing the solute molecules experiences the external pressure. This action causes the process of osmotic pressure.

Considered by scientists and other people who have an interest in osmosis is another factor. Osmosis is a process which is called by many the reversible thermodynamic process. This process is really pretty simple and the explanation in layman terms is as follows. The process, reverse osmosis can be stopped or changed at any time whatsoever just by proper control of the right external introduction. By applying pressure to the right point, the direction of the flow of water or another liquid is then reversed rather than continuing through the flow of the membrane.

Reverse osmosis is often used in water filtering and purification systems in order to purify the water and keep the water clean and free of toxins which most people would not want to experience in their drinking water. The process of reverse osmosis is completely opposite from the diffusion process.

Often diffusion and reverse osmosis are, in fact, confused. However, the diffusion concept is irreversible and the process of reverse osmosis is as the name suggests, reversible.

Reverse osmosis can be studied at length using the online libraries available. Keyword searches bring more individual product information for filtering systems than for explanation of the reverse osmosis process itself. Find out what you need to know for whatever purpose through the extensive research available in the many libraries online. Reverse osmosis is worth researching further if you have the time and the interest to do it.

Reverse Osmosis

MEMBRANE

How to Lighten Your Skin Naturally - How to Get Beautiful Pale Skin in One Month Safely

There are various home remedies available for lightening your skin naturally. You should always take up healthy and membrane friendly treatments for diminishing freckles, age spots, liver spots, hyper pigmentation and skin discolorations. Most people experiences this problem due to excess exposure to sun and hot climatic conditions which increases the production of Melanin. In order to get a beautiful pale skin, we should pamper our membrane by employing good creams and techniques.

waterproof membrane

Skin Lightening Tips

MEMBRANE

* It is always advisable to use a natural cleanser for washing your face. You can prepare them from the comfort and convenience of your home by using mashed strawberries. A natural cleanser helps in cleaning dust particles, which gets deposited in your face due to constant exposure to sunlight and air.

* Your cleaned covering can be further treated by using grated potatoes which is rich in natural bleaching agent should be mixed with honey and lemon juice and applied onto your face. This process can easily lighten your skin tone. This process rejuvenates your membrane and promotes a smooth skin tone.

* A natural lightening cream mainly contains Kojic acid ester, Alpha hydroxy acids and Asefidita extract. These ingredients can easily brighten your covering by exfoliating colored skin on the surface.

* Meladerm is the most touted skin lightening which incorporates a unique formula for diminishing darkening elements in your membrane by blocking the production of melanin. Some of the main ingredients of this product are mulberry extract, licorice extract, and lemon juice extract and kojic acid. This product claims to reduce the visibility of hyper-pigmented skin.

* The absence of Hydroquinone makes this product a safe option. Hydroquinone can cause various deadly diseases such as liver damage, leukemia and thyroid disorders.

How to Lighten Your Skin Naturally - How to Get Beautiful Pale Skin in One Month Safely

MEMBRANE

Physiologicoanatomical Peculiarities of the Respiratory System of Newborns

The basic tips you need to know in the physiologicoanatomical peculiarities of the respiratory system of newborns is the peculiarities in the nose, sinuses, pharynx, larynx, trachea, bronchi and the lungs.

kerdi membrane

The Peculiarities of the nose at the neonate
• The nose is particularly made up of cartilage
• The nasal meatuses are narrow
• There is no inferior nasal meatus (until 4 years)
• Undeveloped submucosal membrane (until 8-9 years)

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The peculiarities of sinuses in children
• The maxillary sinus is usually present at birth
• The frontal sinuses begin to develop in early infancy
• The ethmoid and sphenoid sinuses develop later in childhood

The peculiarities of the pharynx at the neonate
• The pharynx is relatively small and narrow
• The auditory tubes are small, wide, straight and horizontal

The peculiarities of the larynx at the neonate
• The larynx is funnel-shaped (in the adult it is relatively round)
• It is relatively long
• The cricoid's cartilage descendents from the level of the fourth cervical vertebra in the infant to that of the sixth in the adult
• The fissure of glottis is narrow and its muscles fatigue soon, vocal ligaments and mucous membrane are very tender and well blood-supplied
• Vocal ligament are relatively short

The peculiarities of the trachea at the neonate
• The length of the trachea is relatively larger (about 4cm unlike in Adult which is 7cm) and wide
• It is composed of 15-17 cartilage rings (the amount does not increase)
• The bifurcation of the trachea lies opposite the third thoracic vertebra in infant and descends to a position opposite the fourth vertebra in the adult
• Mucus membrane is soft, well-blood supplied, but sometime dry,
• It can collapse easily.

The peculiarities of the bronchi at the neonate
• In young children the bronchi are relatively wide
• The right bronchus is a straight continuation of the trachea
• The muscle and elastic fibers are undeveloped
• The bronchi are well blood supplied
• The lobules and segmented bronchus are narrow

The functions of the bronchus
• The ciliated mucus membrane "sweeps" out dust particles
• Transfer of gases into the lungs
• Immunologic function

The functions of the Lung are
• The main function of the lungs is the exchange of Oxygen and carbon dioxide
• To produce surfactant

The peculiarities of the lungs at the neonate
• Size of alveoli is smaller than in adult
• Quantity of alveoli is relatively less than in adult.

Considerable or obvious deviations from these peculiarities indicate abnormalities or further clinical examination.

Physiologicoanatomical Peculiarities of the Respiratory System of Newborns

MEMBRANE

Have You Heard About Laksen?

Laksen is a Danish company which is continuously expanding and introducing new products especially designed for hunting and shooting. The range of products includes clothing and accessories and more recently footwear which have also been introduced. Laksen ensure that their products are comfortable, functional and exceptionally high quality. All of the clothing, footwear and accessories are developed and tested by a variety of dedicated experts, shooters and hunters, who know exactly what is required of the Laksen products.

membrane potentiometer

Laksen produce clothing for both men and women, supplying everything you need for your adventures and sporting activities including tweed, lightweight hunting clothes, camouflage, oilskin, moleskin, leather, fleece, knitwear, shirts and underwear.

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All of the Laksen Tweed products are made using genuine Scottish Sporting Tweed from Thire estates. Although modern technology has made tweed widely available in a variety of countries, this Scottish Tweed has shown, over many years, to be the most hard-wearing, yet comfortable and attractive material around. This Tweed is sometimes combined with a Gore-Tex membrane.

This is a waterproof and breathable membrane, first used by Laksen more than 25 years ago. Gore- Tex aims to keep you dry, comfortable and warm, no matter what the sometimes unpredictable British climate throws at you. Another advanced technology that is used by Laksen is the CTX membrane which stands for Comfort, Technology and eXtreme. It is a completely watertight yet breathable membrane providing comfort regardless of the weather conditions or the wearer's level of activity.

An additional advantage is that it is extremely silent which is important for stalking and hunting. Gore-Tex and CTX membrane are used in many of Laksen's other shooting or hunting jackets and trousers, such as the 'Yack' range which is lightweight but windproof, waterproof and breathable. Laksen also has a range of camouflage clothing and accessories which uses Mossy Oak or Real Tree print and is also available in Blaze Orange for safety.

Laksen's range of underwear works with and compliments the waterproof and breathable outerwear to obtain the ideal balance in your hunting or shooting outfit. The materials used, combined with a specific production process, ensures optimum breathability and insulation. This keeps you body temperature at a stable and comfortable temperature.

Laksen have recently widened the range of products that they provide by introducing a new line of boots, including neoprene boots and lace-up 'hunter' boots available in suede or nubuck leather that also include a CTX membrane. By working with Vibram, one of the world's most recognised manufactures of soles for functional footwear, they have created a range that is functional, comfortable and hard wearing.

I recently purchased some Laksen products from here and they where very good, I even splashed out on a pair of waders while I was there.

Quality accessories made from leather and canvas is also manufactured and available from Laksen. These include travel bags, gun cases, cartridge bags, gun slips and belts. Other accessories such as shooting socks, suspenders, leggings, gaiters, hats and gloves are also produced.

Have You Heard About Laksen?

MEMBRANE

Nose: The Starting Point Of Life-Sustaining Process

THE NOSE

waterproof membrane

The nose is a vital respiratory organ. The nose acts as the primary means of air passage for the human body. The nose is also a sense organ. Moreover, the nose is an important apparatus of the human voice box.

MEMBRANE

LOCATION OF THE NOSE

The nose is the uppermost portion of the human respiratory structure. The nose is basically a hollow structure. Nonetheless, the interior layout of the human nose is quite complex.

FUNCTIONS OF THE NOSE

The hollow cavity of the nose acts as an air moistening and warming apparatus. At the openings of the nasal cavity are small stiff hairs. These hairs called vibrissae act as sentinels. They filter out dust, minute insects and harmful micro-organisms including other foreign particles that flow in the air.

ANATOMY OF THE NOSE

Anatomically, the nose is broadly divided into two portions, viz., external and internal. The purview of the external section is limited. It refers to the centrally located projection portion slightly below the eyes.

THE NASAL PASSAGE

The nose commences the process of flowing air from the surroundings. The air is then transported our lungs. The air is brought within the body via the two nasal openings known as the right and left nasal passages. A flat membrane layer lines up the nasal passages. This lining is made up of thousands of epithelial cells.

Cilia & Epithelial cells: These epithelial cells are rather closely packed. These cells extend as fingerlike objects called cilia. These microscopic cilia line up the fringe of the nasal passages. The inhaled airborne particles are trapped by the cilia - the coarse hairs located inside the nostrils. These trapped particles are then captured by the mucous membrane that forms the lining of the nasal passages. The cilia keep on constantly waving. This creates a current of mucus. The current forces the particles downward. The particles then come downward via the pharynx and finally out through the nose.
Among the epithelial cells are the goblet cells.

Goblet cells & Capillaries: The goblet cells have a specialized function. The goblet cells produce mucus. This mucus is sticky, thick and moist. The cilia and the epithelial cells are coated by this mucus or fluid.
Near the nasal passages and just under the mucous membrane lie the capillaries. The capillaries are minute blood vessels.

NASAL PASSAGE FUNCTIONS

The nasal passages have two important roles. These functions are carried out while the air is transported from the nasal passages to the pharynx.

The filtration process: ages filter the air. Thus it segregates and debars those particles which may cause ailments. If these potentially dangerous elements like viruses and bacteria make their ways into the lungs, there may be infections of various types. The process also prevents dust particles and smog from clogging the smallest bronchioles. These bronchioles have very narrow air passages that need to be constantly kept clean and clear of dirt.

Preserving temperature & moisture: Second, the nasal passages keep the air warm besides maintaining the moistening effect. The warmth and moisture shields the respiratory system structures.

In the pharynx, the mucus is swallowed and passed to the stomach, where the particles are destroyed by stomach acid. If more particles are in the nasal passages than the cilia can handle, the particles build up on the mucus and irritate the membrane beneath it. This irritation triggers a reflex that produces a sneeze to get rid of the polluted air.
The nasal passages also moisten and warm air to prevent it from damaging the delicate membranes of the lung. The mucous membranes of the nasal passages release water vapor, which moistens the air as it passes over the membranes. As air moves over the extensive capillaries in the nasal passages, it is warmed by the blood in the capillaries. If the nose is blocked or "stuffy" due to a cold or allergies, a person is forced to breath through the mouth. This can be potentially harmful to the respiratory system membranes, since the mouth does not filter, warm, or moisten air.

NASAL FOSSAE

The internal portion of the human nose is divided into two cavities. These hollow portions are called nasal fossae. The nasal fossae open through the nostrils and end in a vertical slit on either side of the upper pharynx. The end portion is above the soft palate, and near the orifices of the Eustachian tubes. These Eustachian tube orifices lead to the tympanic cavity of the ear.
The two nasal cavities are vertically separated by a septum or a separation structure. The septum cartilage along with the perpendicular ethmoid plate and the vomer constitutes the partition wall between the right and left nasal fossae. Each of the nasal fossae is again sub-divided into three passages. They are called meatuses. The passages are delineated by turbinated or spongy bones. These boney borders start from the outer walls of the meatuses. These bones use narrow orifices to link with the different sinuses.

TYPES OF SINUSES

The sinuses are boney or tissue cavities in the skull. The sinuses connect the nostrils within the skull. The various sinuses are in the ethmoid, sphenoid, frontal, and superior maxillary bones. Inflammation of the sinus leads to the dysfunction called sinusitis.

NASAL FRAMEWORK

The nasal framework or the skeleton of the nose is formed of bones and cartilages. The bones constitute the top and sides of the nasal bridge. On both sides of the bridge are the cartilages. One is the upper lateral cartilage. The other is the lower lateral cartilage. Three to four other smaller cartilaginous plates known as the sesamoid cartilages are attached to the lower lateral cartilage.

DISEASES OF THE NOSE

NOSEBLEED: This common ailment is medically called epistaxis. Many factors can cause nosebleed. More often than not, nosebleeds take place due to minor irritation. Injury of the small septum veins (on the partition dividing the two nasal sides) can also lead to nosebleed. Rupture of these septum veins can occur spontaneously, or it may be caused by a cough or a sneeze. The sudden shock raises the blood pressure inside the nasal veins. This leads to the nosebleed.
Usually, nosebleeds stop in a short time. However, recurrent nosebleed may be signs of underlying serious diseases. Mention may be made of blood vessels diseases, certain cancers like leukemia, abnormally high blood pressure, infection, and nose tumors.
Treatment: The best way to stop persistent nosebleed is to apply pressure over the bleeding site. A cold compress can also help. The moment a person has nosebleed, he/she should immediately lift up his nose so that the blood flow direction is reversed. But if these remedies fail to yield the desired results, seek immediate advice from a doctor. Recurrent or severe nosebleeds do need urgent medical attention.

RHINITIS: This is an inflammatory disorder. Rhinitis affects the nasal mucous membrane called the nasal catarrh. The common symptoms of rhinitis are watery discharge from the nose. It can also be accompanied by nasal congestion. There can be breathing problems as well. Many rhinitis cases are caused by the common cold. Other factors can be other diseases, certain medications, irritation from pollutants and other elements, and nasal allergies.
Treatment: Generally, nasal decongestants shrink and dry up the swollen mucous membranes. Local use of nasal sprays and drops can also help. Breathing of menthol put in a cup of lukewarm water also helps to relieve congestion. However, excessive use of any of these treatments can dry up the membranes. They can even damage the sensitive nasal membranes. Allergic rhinitis is treated with antihistamines.

HAY FEVER: AS hay fever occurs in the same season it is identified as a seasonal rhinitis. Hay fever is caused by allergy to pollens. The hay fever symptoms are wheezing, nose and eye membrane inflammation, and acute sneezing seizures. Family sensitiveness to hay fever can be a cause of the hay fever symptoms in any individual. Studies have shown that about 10 American citizens are prone to hay fever symptoms.
Treatment: Physicians treat hay fever by determining the sensitizing agent(s). The patient's skin is first scratched and various pollens applied. A wheal-and-flare reaction is produced by the pollen to which the patient is allergic. The hay fever syndrome is activated when the body releases histamine as a counter to the antigen-antibody reaction. This release of the histamine irritates the glands and the blood vessels. Notably a few of the anti-histaminic agents can provide relief. A series of pollen extracts injections as a preventive measure prior to the advent of the pollen producing season has delivered positive results. This is a long-term therapy.

COMMON COLD: This acute infectious disease is caused by more than 100 different types of viruses. Common cold affects the mucous membrane of the upper respiratory tract. The symptoms of common cold are coughing, sore throat, nasal discharge and nasal congestion. Many of these bacteria-caused symptoms are similar to the allergic nasal conditions arising from asthma hay fever. Hence, it is not very easy to diagnose common cold.
Common cold can be accompanied by fever as well. It has been seen that common cold conditions subside within a week's time. However, complications may arise from severe common cold. This can lead to many diseases like middle-ear infections or sinus, pneumonia and bronchitis.
Different viruses have various strains and therefore degrees of virulence. Hence if a patient takes medication for a particular virus or a strain or a degree of attack, that medication may not be affective with respect to another virus. The same strain of the virus but with a different degree of virulence can again strike. So it is not uncommon to find that even after one has taken a full dose of a medication, that person again gets down with another bout of common cold.

Earlier beliefs: In the olden times, the common belief was that exposure to cold conditions caused common cold. This feeling was partly buttressed by the fact that during such a drab weather condition the people used to huddle together. The result was that common cold conditions easily spread from one another. Another school of thought pinpointed chilling as a cause of common cold. It extended the infections that were consequent upon the chilling effect as the reason. However, studies have proved that the chilling effect can be one of the causes, though not the main cause.

In the 1950s, antihistamine medications were prescribed as the treatment if the common cold was detected at the initial stages. Now the consensus among the physicians is that these drugs do not address the progression of the ailment or neutralize the virus producing the symptoms.
Nobel laureate and American chemist Linus Pauling came up with the proposition that Vitamin C doses in large quantities shorten the cold duration. He further stated that the vitamin alleviates the symptoms. However, follow-up researches have proved that this contention is untrue.

3-dimensional picture of the common cold virus: Way back in 1985, American medical scientists were successful in bringing out a three-dimensional model of a common cold producing virus. That scale was in the atomic scale. The atomic scale model in the three dimensional format of the virus causing common cold created a sensation. The scientists utilized the advanced techniques of X-ray crystallography.
The studies were concentrated on the viral coat. It specifically took up the coat sites that was antibody binding. They showed a rather high degree of variability. This was particularly true with respect to the antigenic factor. Further researches on the findings demonstrated it is impossible to formulate that a panacea for all common colds.

Modern methods to treat common cold: The modern-day techniques are concentrated on addressing or relieving the patients of the common cold symptoms. This method is given a backup by a medication move to prevention recurrence of the complications. To avoid complications the patients are advised bed rest. Even when the cold is not so severe, bed rest helps because the general constitution of the patient remains weak. Moreover, if the patient remains in bed, the chances are dim of the contagious disease attacking others. More often than not, as a preventive move, antibiotics are administered. But no direct connection has yet been found between the antibiotics and its effects on the common cold causing virus.
Interestingly enough, common cold has been found to be the major cause of absenteeism in educational institutions and industries.

INFLUENZA: This is an infectious and a contagious ailment. It is commonly termed as flu and also grippe. Influenza is usually acute. Influenza especially attacks the trachea, an important part of the respiratory tract. A simple influenza bout is accompanied by several symptoms. They can be eye burning, sore throat, dry cough or even discharges from the nose or nasal obstruction. The symptoms disappear and the body temperature resumes the normal level in such simple influenza instances.

Nose: The Starting Point Of Life-Sustaining Process

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Concrete Crack Repair in Basement Walls

Concrete cracks in nearly every wall in a basement. Builders and contractors plan for this cracking by placing steel reinforcing inside the concrete walls. Even though the concrete has cracked, this reinforcement maintains the strength of the wall and it is not a problem for a typical home's foundation.

waterproof membrane

Ways Water gets into the Basement

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Unfortunately these concrete cracks allow water to enter the basement. Many homes built today have a waterproofing membrane on the outside of the foundation to control the water and keep it from getting into the basement interior. Older homes are vulnerable to water leaking in because they do not have a waterproofing membrane installed at all. But it is still possible for the crack to be too large for the waterproofing to stretch over the crack and the membrane then tears. Or if the grading is incorrect and slopes toward the house, rainwater will pool next to the home above the level of the waterproofing, enter the concrete crack and flow to the interior. Finally, it is possible for a home's landscaping to be above the protective waterproofing and let water into the concrete crack above the waterproofing membrane.

Repairing the Concrete Crack

Homeowners or professional can fill the crack from the inside of the basement and prevent water from leaking in. Making the repair from the inside is a cost effective and quick method that does not disturb the soil and landscaping on the outside. The repair to the concrete crack is done by injecting an expanding urethane foam into the crack.

Liquid Urethane Foam Injection

The urethane enters the crack as a liquid and when it encounters water, it begins to foam and expand. This expansion forces the foam to completely fill the crack from bottom to top and from front to back. When finished, the foam will keep the water where it belongs, on the outside of the concrete foundation.

The width of the crack does not matter. If water can get through the concrete crack, so can the liquid urethane. This is because the urethane is injected under low pressure with either a standard caulk gun or if done by a professional, by a special dual cartridge gun. A home owner or professional does not have to do any drilling or chiseling to make the crack wider.

While water is required to be present to act as a catalyst to make the urethane to begin to foam, the repair can still be done if the crack is dry. Simply inject 1/2 cup of water into the concrete crack with a spray bottle to make the concrete crack wet inside it.

A Dry Basement

Once the concrete crack is filled with urethane foam water will not be able to leak into the basement. The homeowner can now finish the basement and be sure that the contents will be safe and dry for years to come.

Concrete Crack Repair in Basement Walls

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Definition of Hyaline Membrane Disease Respiratory Distress Syndrome (RDS I)

Also known as idiopathic respiratory distress syndrome (RDS) Type I, hyaline membrane disease is an acute disorder found primarily in preterm infants at birth of shortly after birth, most often in infants under 32 week's gestation who weigh less than 3 lb, 4 oz (1,500 g). Roughly 60% of infants born before 29 week's gestation develop RDS.

membrane potentiometer

Fetal lung development and surfactant production are necessary for normal respiratory function; lung development and surfactant production varies with each infant. The preterm infant is born before sufficient surfactant develops or with a lack of mature surfactant production. Surfactant, a lipoprotein that lines the alveoli, prevents alveolar collapse and decreases the work of respiration by decreasing surface tension. With a deficiency, surface tension increases, causing alveolar collapse and decreased lung compliance, which affects alveolar ventilation, leading to hypoxemia and hypercapnia with respiratory acidosis. The reduction in ventilation leads to a poor ventilation and perfusion ratio of the pulmonary circulation, resulting in hypoxemia. Tissue hypoxia and metabolic acidosis result with associated atelectasis and respiratory failure progression.

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RDS, the leading cause of mortality and morbidity in preterm infants, usually lasts 3 to 5 days. The prognosis is poor if prolonged ventilator support is needed; death is less likely after 3 days of treatment.

This plan focuses on care of the infant at risk for or with RDS and on all the associated respiratory support that may be needed.

Etiology and precipitating factors
• prematurely with immature lungs (ranges less than 32 to 35 weeks' gestation) and absence, alteration, or deficiency of pulmonary surfactants
• cesarean delivery of preterm infant
• decreased oxygen present in the fetus or at birth in term or preterm infants

Physical findings

Maternal history
• disorder such as diabetes mellitus
• condition such as placental bleeding
• type and intrapartal stress

Infant status at birth
• prematurely, gestational age
• apart score noting asphyxia
• cesarean delivery of preterm infant

Cardiovascular
• bradycardia (less than 100 beats/minute) with severe hypoxemia

Integumentary
• pallor caused by peripheral vasoconstriction
• pitting edema in hands and feet within 24 hours
• mottling

Neurologic
• immobility, motionlessness; flaccidity
• decreased body temperature

Cardiovascular
• systolic murmur
• heart rate within normal limits

Pulmonary
• tachypnea (more than 60 breaths/minute' may be 80 to 100)
• expiratory grunting or whining
• nasal flaring
• intercostals, suprasternal, or substernal retractions
• cyanosis (circumoral followed by central) related to percentage of destructed hemoglobin
• Decreased breath sounds, crackles, apneic episodes.

Behavioral findings
• lethargy

Diagnostic studies
• serial chest X-rays - reveal clouded appearance with grainy look, areas of density or of atelectasis, and elevated diaphragm with over distended alveolar ducts
• air bronchograms - reveal ventilation of the airway, not the alveoli

Laboratory data
• lung profiles - to determine lung maturity; done on amniotic fluid (for fetuses predisposed to RDS):
o lecithin/sphingomyelin (L/S) ratio of
2:1 or more indicates pulmonary maturity
- 1:1 before 35 weeks' gestation (L: 6 to 9 mg/dl,
S: 4 to 6 mg/dl)
- 4:1 after 35 weeks' gestation (L: 15 to 21 mg/dl,
S: 4 to 6 mg/dl)
o Phosphatidylglycerol: elevated at 35 weeks' gestation
o Phosphatidylinositol level

• Arterial blood gas (ABG) levels - PaO2 less than 50 mm Hg while on 100% oxygen, PaCO2 less than 60 mm Hg, oxygen saturation 92% to 94%, pH 7.31 to7.45
• Potassium levels - increase as potassium is released from injured alveolar cells

Definition of Hyaline Membrane Disease Respiratory Distress Syndrome (RDS I)

MEMBRANE

Mobile Home Roofing - Now Your Roof Can Literally Move

Mobile home roofing is home construction convenience wherein the roofs are pre-cast before installation. This makes it easy to set on the house, saving the homebuilders time in connecting one roofing material to the other. Using a circular-knit rubber membrane that fits your roof, the mobile home roofing method is one easy system that gives home owners a shorter time to anticipate a finished job.

membrane keyboard

Components of Mobile Home Roofing

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Mobile Home Roofing emerged in the US during the 1960's and has been used for over forty years in the West. The key element in Mobile Roofing is EPDM, or "ethylene propylene diene monomer", rubber which is 45 mil compacted and preformed and cut to fit the roof in a single job.

The material of mobile roofing is resistant to impact, puncture and tear. It is made to stand very hot and cold temperatures, as it builds motion and thermal shock. It also lessens noises in roofs caused by the wind, which gives a relaxing ambiance for families to comfortably rest. White Elastomeric Roof, Peal and Seal, Kool Seal Aluminum Roof, Brewer Cote Plastic Roof, Stone Patch Flexx Sealer are just among the many samples of mobile roofing styles.

After problems with leaks in mobile home roofing materials in 1978, a new type of system was invented by Bob May, which includes insulating the material then rolling out the sheet with the roof membrane. This allowed the roof to be automatically attached into the deck which guarantees the membrane to be fixed around the edges. Such a membrane radiates 78 percent of the heat of the sun, which helps warm up cold areas.

Cost Worthy

Not only is mobile home roofing worthy of a purchase, it is also cost-effective since it usually comes in a complete package. These mobile roofs can also last for twenty years or more with no special instruments used during installation. The set up of mobile home roofing can done by the local handyman or by the home owners themselves.

Also, with the help of roofing calculators, ordering for a desired roof size is made easy and less time-consuming. More conveniently mobile home roofing can be bought online.

Some websites even accept orders with customized appearances, making the roofs more attuned to the owner's taste. And if there is a problem on the roof ordered, calling for help is easier because mobile home roofing materials also come with warranties. With this system, everyone can definitely have their own houses without having to wait too long and, yet, be assured that they have sturdy roofs over their heads for a lifetime.

Mobile Home Roofing - Now Your Roof Can Literally Move

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Sports Injury Pain Relief With Natural Eggshell Membrane

If connective tissue damage is keeping you from participating in the sports you love, Natural Eggshell Membrane (NEM) may be the key to getting you back out on the field. Connective tissue damage is common in sports injuries, strains and sprains. This kind of damage manifests as muscle stiffness, aches and the loss of flexibility. These symptoms are commonly overlooked as a part of the natural aging process or simply as normal effects of being active. But joint pain, muscle aches and loss of flexibility can signal connective tissue damage, which if left untreated can result in keeping you out of the game permanently.

kerdi membrane

Treatment and repair of damaged tissue is a complicated process that hinges on controlling inflammation to allow your body to begin repairing tissue. Inflammation can be treated using over the counter medications, vitamin C and Zinc, and other non-prescription treatment options. If inflammation isn't controlled, then the processes necessary to help repair tissue damage cannot take place. Connective tissue repair is actually a two part process that consists of first addressing inflammation and second, providing the necessary nutrients and tools to your body to begin the repair process.

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It is the repair process that can be most helped by NEM. Natural eggshell membrane can help repair connective tissue damage and relieve joint and muscle pain. NEM is the thin membrane between the eggshell and egg white. NEM contains the proteins that are necessary to help repair connective tissue damage.

If you want to get back in the game, a daily supplement containing NEM may be able to help. Supplements that contain natural eggshell membrane are effective, because they contain a high level of NEM. Natural eggshell membrane not only helps repair tissue damage, but it also works to maintain the synovial fluid necessary to keep your joints and tissue healthy. Synovial fluid is located in your joints and helps keep them lubricated so your movements are smooth and painless.

Sports Injury Pain Relief With Natural Eggshell Membrane

MEMBRANE

Building on Landfill Sites

We would like to emphasise that, if at all possible, building on landfill sites containing putrescible material, and which therefore are likely to be generating landfill gas should be avoided.

membrane pump

Some old landfills will be free from landfill gas, but do take great care to obtain expert advice before you assume that any particular landfill is truly free from landfill gas, and
that therefore no risk exists. We have found that landfill sites are continuing to produce significant volumes of landfill gas, for many years and many sites are still producing gas after in excess of thirty years from closure.

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However building land is in short supply in so many countries, and there are strong arguments to suggest that even in regions where land is still plentiful, we should re-use the land if at all possible. Building has taken place on some gassing landfill sites and no doubt more will take place in the future.

Experience has being gained in suitable protection measures, and it is apparent that two primary problems i.e. subsidence and methane/odour, have to be overcome.

Solutions are easiest if the landfill is not deep e.g. 3-4 m thick where digging out the waste locally to structures, followed by replacement by inert fill may be both the safest
against explosion in case landfill gas seeps into the property, and be economically the most viable. An interceptor trench is often then required to prevent gas migrating from the remaining waste into the inert fill.

If it is not practical to remove the waste, then buildings are normally erected on base slabs which are themselves supported on piles driven into firm ground below the base of the landfill. The use of this construction technique will overcome subsidence problems.

The problem remains of preventing landfill gas present underneath the base slab from entering the building above. The simplest approach is to build an air space under the slab; the void is then ventilated naturally or artificially.

This technique has been used in the construction of many warehouses, supermarkets, and sports facilities. The normal practice has been to provide an air space of 300mm to 500mm depth, but some have been constructed as much as 1-1.5 m high to encourage dissipation of the gas by natural convection over large areas. Clearly, the use of natural air currents to vent the gas to the atmosphere is inherently safer than to rely on electrically driven fans, which may fail for many reasons.

Covering the ground underneath the slab with impervious material or a plastic membrane may help to minimise odour/gas emissions. Another approach is to again use piles but to lay the slab on a layer of porous rock on the landfill surface. Horizontal perforated pipes are placed in the porous material and are continuously pumped under a suction pressure, so that 1-2 air changes per hour are maintained under the slab, in some designs. However, the airflow rates required do vary greatly and need to be set by experts, in the knowledge of the rates of possible ingress at the site, under the maximum gas generation periods (normally during the highest rates of falling atmospheric pressure). This system has been successfully used in many properties, however, any system of forced ventilation will require to be maintained for many years, and the owner and future purchasers will have to commit to the cost of this.

These systems are often backed up by incorporation of a plastic membrane below the slab itself. Attempts to render concrete slabs impervious to gas by painting them with sealants have met with little success.

Surprisingly large volumes of gas can penetrate small cracks in concrete. It has been suggested also that gas problems can be overcome simply by spreading a thick (at least 1 mm, and normally HDPE) continuous plastic membrane over the ground surface and building on it, with suitable protection above and below the membrane to prevent penetration. This technique has been successfully carried out on at least one London motorway services area.

However, if the structure is above waste, this will settle over time, and piling is required to overcome subsidence, then one is faced with getting a good seal between the membrane and the piles which will remain intact after settlement. Attempts are often necessary to avoid trapping gas in pockets between cross-members under the slab, especially if groundwater level rises might push the gas upwards under pressure at any time.

It is also essential that if services such as electricity, gas, water, drainage, telecoms related etc, penetrate the slab (or raft) that they are also sealed in a satisfactory, and truly permanent, fashion.

As a final precaution it is suggested that rooms at risk in buildings on landfills are fitted with audible gas detection devices or that monitoring for methane is carried out regularly
both during the construction phase and after the building is occupied.

The extracted gas can simply be vented to the air, but if significant flows of gas are involved it should be flared, both to overcome odour problems, and to comply with requirements of the environmental regulators. In most developed countries the regulators will require flaring in order to reduce greenhouse gas emission rates.

All these precautions may seem stringent, but one must never forget that a gas explosion, if it was to occur, is a highly dangerous event and the risk of major injury is very high. For

this reason both passive and active landfill gas migration risk prevention measures are normally used in tandem in these buildings.

All designs must be based on a good quality scientific data and detailed risk assessments, prepared only by acknowledged experts in this work.

Building on Landfill Sites

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