Polyethylene Strips Research Articles

Field Evaluation of Simulium Larvicides: Effects on Target and Nontarget Insects

The effectiveness of three blackfly larvicides, FMC-45497 (10% EC) [(-)-cyano )-3-3 phenoxybenzyl-(±) cis -3-(2,2-dichlorovinyl)-2,2-dimethyl cyclopropane-1-carboxylate], Abate® (50% EC) [ 0,0,0',0' -tetramethyl-0-0'-thiodi- p -phenylene phosphorothioate], and the insect growth regulator (IGR) Dimilin® (25% WP) [1-(4-chlorophenyl)-3-(2,6-difluorobenzyl) urea], was studied in the field against target Simulium , and their impact on selected aquatic nontarget insects was determined. Effectiveness and impact were assessed by three sampling techniques: drift net, Surber sampler, and polyethylene strips. Interval drift samples gave rapid evaluation of the effectiveness of the fast-acting larvicides FMC-45497 and Abate®. For Dimilin®, which is slow-acting, Surber sampler and polyethylene strips were more suitable because drift among aquatic organisms was not induced when Dimilin® was applied at 0.1 ppm/15 min. After the application of FMC-45497 at the rate of 0.01 ppm/15 min, catastrophic drift was noted in some components of the aquatic fauna, Baetis , Chironomidae, Hydropsyche , and Odonata. Baetis naiads constituted over 85% of the drifting organisms in number. Abate® applied at 0.1 ppm/15 min was selective, producing drift in Simulium larvae only, and Dimilin® at 0.1 ppm/15 min caused moderate decline in Simulium larvae and Baetis and Hydropsyche .

Formation and peculiarities of heterogeneity in polyethylene samples obtained by extrusion

Three-layer structure was observed in the polyethylene strips obtained under definite conditions of extrusion, with the high degree of orientation of the core layer being most remarkable. The wide-and small-angle X-ray investigation of the different layers of the strips and the pole figures analysis were performed. In the outer layers a texture is formed. Crystalline structure formed in the core is characterized by almost regular cylindrical arrangement of a and b axes around the extrusion direction. The c axes direction almost coincides with the extrusion direction. In the core of the extruded strand, lamellae are arranged in parallel stacks. The angle value between the normal to the lamellae surface direction and the extrusion direction is about 30°.

Bizarre implants for augmentation mammaplasty: Long term human reaction to polyethylene strips

Two patients are described where a mass of polyethylene strips had been used for augmentation mammaplasty. The reaction to this plastic was different in each case.

Description of a new device: an intranasal airway/splint.

Over the past two decades, the concept and practice of using septal splints has gained in popularity. Various methods have been used including X-ray film, sheets of Teflon and strips of Polyethylene. In this presentation a new device is introduced which incorporates the principles of septal splinting, along with the simultaneous use of nasal breathing tubes. A brief history of septal surgery and splinting is discussed, and the new device is described, both in its configuration and usage.

Equipment for producing long strips of high molecular weight polyethylene (HMWPE)

Equipment for producing long strips of high molecular weight polyethylene (HMWPE)

Establishing brood stock of grey mullet ( Mugil cephalus L.) in small ponds

A brood stock of 3-year-old grey mullet ( Mugil cephalus L.) was maintained in two small rubber-lined outdoor ponds with circulating sea water. Plastic substrate consisting of weighted polyethylene strips was placed in each pond to increase surface area and provide a stable supply of benthic diatoms, blue-green and filamentous green algae. Water chemistry and daily fluctuations in oxygen, pH and temperature were monitored. Some fish developed air embolisms resulting from oxygen supersaturation, causing mortality. All males and females matured the following year and those not sacrificed for experimental data were induced to spawn by hormone injections.

Lymphopenia produced by polyethylene- 32P strips applied to the rabbit appendix

Local, continuous irradiation of the rabbit appendix was produced by attaching to the outer surface of the organ polyethylene strips impregnated with the β-emitting isotope 32P. This procedure reduced the level of small lymphocytes in the blood to 20–25% of the preoperative level after 1 week. The labeling index of small lymphocytes after a single injection of 3H-thymidine showed that there was little or no reduction in the rate of lymphocyte production after attachment of 32P strips. It is argued that the most likely mechanism of the lymphopenia is destruction of a major population of blood lymphocytes which recirculate continuously between the blood and the lymphoid tissue of the appendix. The existence of lymphocyte recirculation within the appendix is regarded as additional evidence that this organ serves a peripheral lymphoid function. Although marked lymphopenia was maintained for 8 weeks or longer, no defect in antibody formation or skin graft rejection was detected. Candida albicans infection of joints progressed and then regressed in similar manner in both groups, leaving a chronic proliferative synovitis lasting for at least 2–3 months.

A simple method of measuring radiation dose in themegarad range using low-density polyethylene film

The method is based on the observation that, for a certain range of dosesabove the gel point, when polyethylene strips loaded with small weights are heatedunder controlled conditions, the breaking temperature is a linear function of radiationdose. The slope and extent of the linear function has been investigated and foundto depend on the orientation of the polymer chains in the films, the molecular weight,the film thickness, the loading stress and the dose rate (in the presence of oxygen).The effect apparently did not depend on the energy and the nature of the radiation,or the time between irradiation and measurement. With pre-irradiation, the steeplinear slops might also be used to measure doses below one megarad. The method isnot as accurate as some other methods but is cheap and simple to carry out.

Immunosuppressive Effect of the Depletion of Circulating Lymphocytes by Chronic Irradiation of the Rat Spleen

Abstract The effect of chronic irradiation of the spleen with a 32P polyethylene strip applied to the lateral surface of the spleen on the blood level of circulating small lymphocytes and on the immune response to 2,4-dinitrophenyl-bovine γ globulin administered in complete Freund's adjuvant was investigated in the rat. Irradiation restricted to the spleen caused severe lymphopenia and significantly depressed the cellular and humoral immune response to this antigen.

Effect of bending and stretching of polyethylene strips on the adsorption of surface‐active substances

AbstractThe adsorption of tritium‐labeled sodium stearate and 35S‐labeled sodium dodecylsulfate from aqueous solution on bent and on stretched polyethylene strips was directly measured. The amount of adsorption increased from 2.5 to 4.5 times on surfaces of various polyethylene samples stretched from 5.2 to 5.3 times the original length. For one sample, adsorption increased 8 and 2.5 times, respectively, on the convex and concave surfaces of a bent strip. Autoradiographs of the strips taken after adsorption revealed the appearance of both homogeneous and heterogeneous adsorption on the stretched surface of the polyethylene. The electron micrographs of the strips showed that many small fissures, about 1–5μ in length, formed on their surfaces after the strips were bent or stretched. Enhanced adsorption of the surface‐active substance along these fissures was suggested. On the basis of these observations, it is proposed that in stretching or bending, fissures increase adsorption of the detergent, and the adsorption in turn promotes further development of fissures. Thus, bending and adsorption mutually promote the growth of fissures which finally result in failure of the polyethylene.

Influence of Supplemental Light on Apparent Photosynthesis, Yield, and Yield Components of Soybeans (Glycine max L.)1

Experiments were conducted to determine the effect on soybean seed yields and yield components of increasing the amount of light available in the soybean leaf canopy and to evaluate the photosynthetic contribution of leaves at different levels in the canopy.Wide spectrum fluorescent lamps were placed at three levels in the canopies of ‘Amsoy’ and ‘Wayne’ varieties planted in rows 50‐cm and 100‐cm apart. White reflective polyethylene strips were placed between the rows. At harvest each plant was divided into top, middle, and bottom thirds corresponding to the levels of artificial lamps in the canopy.Measurements of apparent photosynthesis (AP) and respiration of individual soybean leaves were made with a plexiglass single leaf photosynthesis chamber. AP and respiration rates (rag CO2/dm2/hr) were determined by recording the change in CO2 concentration with time in a closed system.Adding light increased the yields of bottom, middle, and top canopy positions of plants 30, 20, and 2%, respectively. Light‐rich plants had more seeds, nodes, pods, branches, pods per node, seeds per pod, and a higher oil content than normal plants. Protein content and seed size were decreased by adding light.The rates of AP of bottom and middle soybean leaves were 13 and 60% of the 20.2 mg CO2/dm2/hr rate of top leaves under natural canopy conditions. When exposed to full sunlight, bottom and middle leaves fixed 258 and 50% more CO2, respectively, than when naturally shaded.Respiration rates decreased with depth in the canopy. Top, middle, and bottom leaves had respiration rates of 6.8, 4.3, and 2.8, mg CORespiration rates decreased with depth in the canopy. Top, middle, and bottom leaves had respiration rates of 6.8, 4.3, and 2.8, mg CO2/dm2/hr, respectively.

Ultrasonic Phase Microscopy

An ultrasonic microscope operating at 9 Mc and using phase contrast has been described which can detect a polyethylene strip 112 thousandths of an inch thick and 40 thousandths of an inch wide.

Microclimates on Spring Frost Nights in Napa Valley Vlneyards

Three years9 recordings of night climate during spring frost conditions were evaluated in Napa Valley vineyards of California. On clear nights, shoot temperature was 4°F lower than air temperature. Therefore, 27° was set as threshold vine temperature, for frost damage, since the long established threshold air temperature was 31°F, which could also be confirmed on some frost nights in 1959 and 1960. Covering with 4-ft wide black polyethylene strips kept night temperatures of the vines 3°F higher than in unprotected vines, insufficient protection against stronger frosts, which occur in one out of four years in Napa Valley. At 30-ft height the air was 2°F to 5°F warmer than in the 4-ft standard shelter, which means a difference of 6°F to 9°F between 30 ft and the vines. This appears to be a satisfactory base for operation of wind machines, which, however, would need some support on very severe nights. the use of heaters alone, the most reliable method, encounters the difficulty of fighting sudden sharp temperature drops at sunrise time, during which lighting might not proceed fast enough.

The Sterilization of Polyethylene Bags by Electron Irradiation and a Bacterial Monitor as a Measure of Sterility

By means of a bacterial monitor, it was found that a 2 megarad dose of high velocity electrons will sterilize 0.353 inch of polyethylene. A new bacterial monitor was devised which serves as a direct measure of the sterilizing effect of irradiation on microorganisms. The bacterial monitor is a sealed polyethylene envelope containing polyethylene strips infected with spores of Bacillus thermoalimentophilus . The bacterial monitor may be used to establish the sterilizing capabilities of electron accelerators and may be used as a routine control check on sterilization by irradiation.

Oriented Overgrowth of Paraffin Wax Crystals on Spherulites of Polyethylene

IN spite of the absence of polar groups in the paraffin molecule, oriented overgrowth of the crystals of paraffin wax can be readily obtained not only on ionic substrates such as sodium chloride and lithium chloride and on substrates with polar groups such as chloranil and anthraquinone but also on crystals of aromatic hydrocarbons ; for example, anthracene and phenanthrene1. R. B. Richards2 even obtained oriented overgrowth of paraffin wax crystals on the surface of strips of cold-drawn polyethylene.

Oriented overgrowth on cold‐drawn polymers

AbstractOriented overgrowth of paraffin wax crystals, grown from solution, has been observed on the surface of cold‐drawn strips of polyethylene and of polyethylene sebecate, but not on oriented gutta‐percha, rubber, polyethylene terephthalate, or nylon. The distribution of the angles at which the platelike paraffin crystals lie on polyethylene has been measured. This is found to be narrower than the angular distribution of the crystalline regions in the polymer as a whole, as calculated from the x‐ray diffraction pattern, suggesting that the crystallites in the polymer surface are more perfectly oriented than in the interior.