Plastic wrapping

You see that vacuum adapter stuck to the top of the condenser in fig. 7a Well, a closer look at it in fig. 7b will show that it has some drying agent sandwiched between two cotton balls and the nipple (tee heel) sealed with plastic wrap or foil. The drying agent can be either a commercial product called Drierite or calcium chloride. This attachment is placed on top of a condenser when refluxing solutions that have no water in them and must remain that way during the time they are refluxed. All this is to prevent moisture in the outside air from coming into contact with the cold surface of the of the inside walls of the condenser. This will surely happen and the condensed outside-air water will drip down into the reaction flask and ruin the experiment. This is not so much a... 

Reynolds plastic wrap (trademark of Reynolds Metals Co.). 

Rubber products may be protected against ozone attack by the use of a highly saturated rubber molecule, the use of a wax inhibitor which will "bloom" to the surface, and the use of paper or plastic wrappings to protect the surface. Despite these efforts, rubber products still crack more on the West Coast than on the East Coast of the United States. 

TOPICAL CORTICOSTEROIDS. Before drug application, die nurse washes the area with soap and warm water unless the primary health care provider directs otherwise Topical corticosteroids are usually ordered to be applied sparingly. The primary health care provider also may order the area of application to be covered or left exposed to the air. Some corticosteroids are applied as an occlusive dressing. The nurse applies the drug while the skin is still moist after washing with soap and water, covers the area with a plastic wrap, seals it with tape or bandage, and leaves it in place for the prescribed period of time ... 

Acetylene (ethyne), C2H2, can be polymerized, (a) Draw the Lewis structure for acetylene and draw a Lewis structure for the polymer that results when acetylene is polymerized. The polymer has formula (CH), where n is large, (b) Consider the polymers polyacetylene and polyethylene. The latter has the formula (CH2)W and is an insulating material (plastic wrap is made of polyethylene), whereas polyacetylene is a darkly colored material that can conduct electricity when properly treated. On the basis of your answer to part (a), suggest an explanation for the difference in the two polymers. 

C13-0059. Plastic wrap can be stretched slightly to fit snugly over a food container. Is plastic wrap a thermoplastic or a thermosetting polymer Explain. 

The antiinflammatory properties of such topical agents as halcinonide are usually determined by a vasoconstrictor assay. Topically applied corticosteroids cause a blanching at the site of application, which can be the forearm or the upper back of healthy adults where stratum corneum is removed with cellophane tape. ° The test areas, containing various concentrations of halcinonide, are occluded with plastic wrap and are evaluated on an all-or-none basis. Percutaneous absorption studies with 0.1%... 

Cover the cylinder with plastic wrap or other cover and mix vigorously by rotating the cylinder at least ten times. Be sure that the soil is thoroughly mixed. 

T. Isaksson, C.E. Miller and T. Naes, Nondestructive NIR and NIT determination of protein, fat and water in plastic-wrapped, homogenized meat, Appl. Spectrosc., 46, 1685-1694 (1992). 

Short-term preservation (several weeks) can usually be successfully accomplished by generous application of polyethylene plastic wrap and duct-tape. Be careful in applying the tape to avoid direct contact with the items. The adhesive can be left behind on the part and when removed, can take with it important dust, fibers, or other data. Even short-term preservation requires some control of access, chain of custody documentation and conspicuously posted signs. Many workers are genuinely curious to learn and see for themselves what the damaged or essential part actually looks like, and may unintentionally cause changes. 

Occlusive therapy Occlusive dressings such as a plastic wrap increase skin penetration by 10-fold. Discontinue the use of occlusive dressings if infection develops and institute appropriate antimicrobial therapy. 

For maximum effect, cover the treated area with plastic wrap, held in place by a snug fitting T-shirt or body shirt, mitten, or sock (never hold plastic wrap in place with tape). Wash the treated area the following morning. Excessive sweating may stop after 2 or more treatments. Thereafter, apply once or twice weekly or as needed. 

Delineate the RNA bands on the plastic wrap and then cut them out from the gel using a sterile scalpel blade. 

Elot the membrane dry with soft tissue papers. Wrap the membrane in plastic wrap. 

Tissue sections should not be dried during immunological BISH detection. A humidity chamber/box can be assembled by placing wet paper towels in a tray and covering it with a plastic wrap sheet. PAP pen is often used for creating a hydrophobic barrier that is dissolved with xylene for immunohistochemistry. However, because BISH detection... 

Containers, media and seeds. Glass Petri dishes, 100 x 15 cm, were used with two sheets of 75-mm Whatman 41 filter paper as the absorptive medium. Ten seeds of TAM105 wheat were placed in a radial pattern with the micropyle end toward the center between the two sheets of filter paper. Seeds were hand-selected for normal size and absence of damage. TAM105 was selected because it is the variety used in the ongoing field research on conservation tillage practices. The bottom section of each Petri dish cover was covered with a square of kitchen-type plastic wrap to retard moisture loss before the lid was pressed on. 

Pour off the washing buffer and add ECL reagent mix (1 vol. reagent 1 and 1 vol. reagent 2, about 0.5 ml/cm ) and incubate for 30 s to 1 min at RT. Remove membrane, drain, and place face down to a thin clear plastic wrap. Form a moisture-tight envelope from the remaining wrap and place the wrapped membrane with blot face down onto an X-ray film in a dark room. Be sure that no liquid contacts the film. 

Place a glass plate somewhat larger than the gel over a tray filled with Soln. D. Wet thick filter paper, e.g., Whatman 3MM, with Soln. D and spread it over the glass plate, the ends dipping into Soln. D. Now place the gel on the filter paper and remove air bubbles. Cover the sides of the gel by strips of plastic wrap and put the wetted membrane onto the gel. 

Pills continue to be sold mainly in loose tablet form. Sometimes sold in small plastic bags, prescription bottles, plastic wrap, coin rolls, or tinfoil, more creative packaging occasionally surfaces. For instance, in St. Louis, large quantities are sold in cigarette packs. 

Vehicles and occlusion An appropriate vehicle maximizes the ability of the drug to penetrate the outer layers of the skin. In addition, through their physical properties (moistening or drying effects), vehicles may themselves have important therapeutic effects. Occlusion (application of a plastic wrap to hold the drug and its vehicle in close contact with the skin) is extremely effective in maximizing efficacy. 

LDPEs are flexible and include numerous plastic items such as plastic wraps (cellophane), grocery and trash bags, and diaper lining. 

Dried blood spots are prepared from native blood on standardized filter paper (Whatman 903, Whatman). The paper has to be fully soaked with blood and dried at room temperature. Blood has to be applied from one side only, to ensure even distribution throughout the filter paper. Do not use any plastic wrapping before the paper is completely dry. For further details, consult the guidelines from your closest newborn screening facility or metabolic laboratory processing dried blood specimens. 

Remove the combs after 30 - 60 min, rinse wells with 1 x TAE buffer. Gels may be sealed with plastic wrap and kept overnight. 

Dipole—induced dipole attractions also occur between molecules of carbon dioxide, which are nonpolar, and water. It is these attractions that help keep carbonated beverages (which are mixtures of carbon dioxide in water) from losing their fizz too quickly after they ve been opened. Dipole—induced dipole attractions are also responsible for holding plastic wrap to glass, as shown in... 

Figure 7-5- These wraps are made of very long nonpolar molecules that are induced to have dipoles when placed in contact with glass, which is highly polar. As is discussed next, the molecules of a nonpolar material, such as plastic wrap, can also induce dipoles among themselves. This explains how plastic wrap sticks not only to polar materials such as glass but also to itself.

Temporary dipoles induced in the normally nonpolar molecules in plastic wrap makes it stick to glass. 

Plastic wrap is made of nonpolar molecules and is able to stick well to polar surfaces, such as glass, by way of dipole-induced dipole attractions. Why does plastic wrap also stick to itself so well ... 

Why should you never discard plastic wrap into a hot barbeque grill ... 

Was this youT answer Many plastic wraps contain chlorine. The combustion of this plastic emits a large dose of dioxin and other POPs directly onto your food or into the air you breathe. 

Another important addition polymer is polyvinylchloride (PVC), which is tough and easily molded. Floor tiles, shower curtains, and pipes are most often made of PVC, shown in Figure 12.30. The addition polymer polyvinylidene chloride (trade name Saran), shown in Figure 12.31, is used as plastic wrap for food. The large chlorine atoms in this polymer help it stick to surfaces such as glass by dipole—induced dipole attractions, as we saw in Section 7.1. 

Lay plastic wrap loosely across the top of the pot and secure with the rubber band. The seal should NOT be airtight. Instead, leave two opposite edges of the wrap outside the rubber band to prevent a buildup of pressure in the pot as the water is brought to a boil. Use scissors to trim away any wrap hanging below the rubber band. Place an ice cube at the center of the wrap, which should then sag above the mug... 

Sunlight can also be used to drive your purifier, but to maximize heat absorption, use a dark, nonreflec-tive pot and make a complete seal with the plastic wrap. 

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