Infinite planar arrays of arbitrarily bent thin wire radiators

A plane wave expansion moment method is presented for computing active impedances and current distributions of infinite planar arrays of thin wire radiating elements. The array lattices can be rectangular or triangular. The excitations can be plane waves or progressively phased voltage sources. Each radiating element, including feedline, can be any collection of bent thin wires. Results are given for arrays of straight dipoles with straight feedlines, straight dipoles with bent feedlines, and swept back dipoles (arms inclined with respect to the array planes) with straight feedlines. The experimentally observed phenomenon of array blindness as a consequence of feedline scattering is verified theoretically. The absence of this effect when the dipole arms are inclined with respect to the array plane also is verified.     

Long-lasting neurotrophin-induced enhancement of synaptic transmission in the adult hippocampus

The neurotrophins are signaling factors important for the differentiation and survival of distinct neuronal populations during development. To test whether the neurotrophins also function in the mature nervous system, the effects of brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), and neurotrophic factor 3 (NT-3) on the strength of synaptic transmission in hippocampal slices were determined. Application of BDNF or NT-3 produced a dramatic and sustained (2 to 3 hours) enhancement of synaptic strength at the Schaffer collateral-CA1 synapses; NGF was without significant effect. The enhancement was blocked by K252a, an inhibitor of receptor tyrosine kinases. BDNF and NT-3 decreased paired-pulse facilitation, which is consistent with a possible presynaptic modification. Long-term potentiation could still be elicited in slices previously potentiated by exposure to the neurotrophic factors, which implies that these two forms of plasticity may use at least partially independent cellular mechanisms.     

Manufacturing and impact characterization of soy‐based polyurethane pultruded composites

Composites have several advantages such as high corrosion resistance, high strength to weight ratio, and lower maintenance costs over conventional materials. The major cost drivers for composites are raw materials and manufacturing process. Automated manufacturing processes like pultrusion and low cost raw materials can significantly lower the cost of composites. Polyurethane (PU) resin systems are commonly used in the pultrusion industry as they have higher performance characteristics and manufacturing feasibility when compared to conventional resin systems such as polyester and vinyl ester. Manufacturing cost can be further decreased by the use of bio‐based materials such as soy‐based resin systems. In the present work, solid pultruded panels have been manufactured using the base PU and two soy‐based PU resin systems. Pultruded panels were subjected to low velocity impact testing. Soy‐based PU resin systems showed comparable properties to that of the base PU resin system and is a viable alternative to the conventional petroleum‐based PU. POLYM. COMPOS., 35:1070–1077, 2014. © 2013 Society of Plastics Engineers     

Weekly fluconazole for the prevention of mucosal candidiasis in women with HIV infection. A randomized, double-blind, placebo-controlled trial. Terry Beirn Community Programs for Clinical Research on AIDS

BACKGROUND: Candidiasis is a frequent complication of infection with the human immunodeficiency virus (HIV); however, few data exist about the natural history, prevention, and treatment of mucosal candidiasis in women. OBJECTIVE: To evaluate the safety and effectiveness of weekly fluconazole prophylaxis for mucosal candidiasis in women infected with HIV. DESIGN: Randomized, double-blind, placebo-controlled trial. SETTING: 14 sites participating in the Community Programs for Clinical Research on AIDS (CPCRA). PATIENTS: 323 women with HIV infection and CD4+ cell counts of 300 cells/mm3 or less. INTERVENTION: 200 mg of fluconazole per week or placebo. Open-label fluconazole for candidiasis prophylaxis was permitted after two oropharyngeal or vaginal episodes or one esophageal episode. MEASUREMENTS: Development of mucosal candidiasis, clinical and in vitro resistance of Candida species to fluconazole, survival, and adverse events. RESULTS: After a median follow-up of 29 months, 72 of 162 patients receiving fluconazole and 93 of 161 patients receiving placebo had at least one episode of candidiasis (relative risk [RR], 0.56 [95% Cl, 0.41 to 0.77); P < 0.001). Weekly fluconazole was effective in preventing oropharyngeal candidiasis (RR, 0.50 [Cl, 0.33 to 0.74]; P < 0.001) and vaginal candidiasis (RR, 0.64 [Cl, 0.40 to 1.00]; P = 0.05) but not esophageal candidiasis (RR, 0.91 [Cl, 0.48 to 1.72]; P > 0.2). Relative risks were similar for women who had a history of mucosal candidiasis (RR, 0.5 [Cl, 0.35 to 0.75]) and those who did not (RR, 0.69 [Cl, 0.35 to 1.34]). Absolute risk reduction for patients with a history of infection was 25.6 per 100 person-years, which is more than twice the reduction of 11.2 per 100 person-years seen in patients with no history of infection. This difference reflects the higher risk of patients who previously had an infection. Candida albicans was not usually resistant to fluconazole in vaginal specimens in clinical or in vitro settings; such resistance occurred in less than 5% of patients in each group. CONCLUSIONS: Weekly fluconazole (200 mg) seems to be safe and effective in preventing oropharyngeal and vaginal candidiasis. This regimen has a useful role in the management of HIV-infected women who are at risk for recurrent mucosal candidiasis.     

Characterization of polyurethane composites manufactured using vacuum assisted resin transfer molding

Glass fiber-reinforced polymer composites have promising applications in infrastructure, marine, and automotive industries due to their low cost, high specific stiffness/strength, durability, and corrosion resistance. Polyurethane (PU) resin system is widely used as matrix material in glass fiber-reinforced composites due to their superior mechanical behavior and higher impact strength. Glass fiber-reinforced PU composites are often manufactured using pultrusion process, due to shorter pot life of PU resin system. In this study, E-glass/PU composites are manufactured using a low-cost vacuum-assisted resin transfer molding process. A novel, one-part PU thermoset resin system with a longer pot life is adopted in this study. Tensile, flexure, and impact tests are conducted on both the thermoset PU neat resin system and E-glass/PU composites. A three-dimensional finite element model is developed in a commercial finite element code to simulate the impact behavior of E-glass/PU composite for three different energy levels. Finite element model is validated by comparing it with experimental results.     

Water‐free synthesis of temperature‐sensitive polyacrylamide microgels and pore modeled oil recovery performance

Polymer gel treatments can improve sweep efficiency and reduce water production during oil recovery operations. In this article, a novel suspension polymerization method was developed to synthesize a temperature‐sensitive microgel. The microgel was prepared by suspension polymerization above the melting point of the monomer in a nonpolar solvent without water. Dry microspheres were obtained, which can be readily used without post‐treatment. Two different crosslinkers were employed in the suspension polymerization synthesis to give the particles thermally responsive aqueous swelling properties. After entering pore channels, gel particles expand to engineered size to realize flow profile changes within in a reservoir formation. When dispersed into water under lower temperatures (ambient to 40 °C), the original dry particles can swell about 18 times their original size. Exposure to a harsher environment (e.g., 80 °C) resulted in cleavage of the labile crosslinking agent and some chain cleavage gave a further size expansion. A Millipore film filtration model system was adopted to evaluate pore occlusion performance of the gel particles. It was found that the nuclear pores were effectively sealed by swollen microgels only when gel particle sizes were similar to or smaller than the membrane pores and interpore separation distance. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44581.     

The Wiskott-Aldrich syndrome in the United States and Canada (1892-1979)

Information was collected on 301 cases of the Wiskott-Aldrich syndrome in the United States and Canada Examination of available medical records, death certificates and published case reports on these patients showed that they came from a wide geographic area and many diverse ethnic and racial groups. No significant difference was found in the incidence of cases born between 1947 and 1976; the overall rate was 4.0 per million live male births in the United States. Median survival has increased with time from eight months for patients born before 1935 to 6.5 years for those born after 1964. Seventy-six of the 301 patients (25%) were still alive at last follow-up and ranged in age from 1 to 36 years with a median of 10 years. Causes of death were primarily limited to infections or bleeding, but malignancy represented a significant problem. Twelve percent of the group (36 of 301) developed malignancy, the predominant types being lymphorecticular tumors (23 of 36) and leukemia (7 of 36). The overall relative risk for malignancy was found to be greater than 100 times that of the general population and was found to increase with increasing age.     

Radiation effects of low refractive index,fluorinated methacrylate polymers for fiber cladding

The gamma radiation stability, optical properties, and mechanical properties of 1H, 1H, 3H-hexafluorobutyl and 1H, 1H-heptafluorobutyl methacrylate homopolymers and copolymers were determined and compared to poly(methyl methacrylate), PMMA. The aim of this study was to identify polymers for fiber cladding materials that exhibit improved optical radiation resistance and physical properties. Using ⁶⁰Co source, the samples absorbed 10 Mrads of gamma radiation at 0.04 Mrads/hr in an air environment. UV/Vis transmission spectra were obtained before irradiation, just after 10 Mrads, and regularly thereafter, to track recovery in transmittance. The glass transition temperatures, decomposition temperatures, refractive indices and flexural moduli were also obtained. Poly(heptafluorobutyl methacrylate) exhibited the greatest resistance to radiation induced discoloration and the lowest refractive index of the compositions tested. As the composition of the copolymers increased in hexafluorobutyl methacrylate concentration, both the radiation induced discoloration and the refractive index increased.     

Microstructure Evolution of Commercial Pure Titanium During Interrupted In Situ Tensile Test

Microstructure evolution of commercial pure titanium is investigated by interrupted in situ electron backscatter diffraction (EBSD) measurement during tensile deformation along transverse direction at room temperature. After 24 pct elongation, the split basal texture of initial material is weakened and rotated around 90 deg along normal direction (ND). \({{11}\bar{2}{{2}}}\)-\({{10}\bar{1}{{2}}}\) double twin is the main reason for the change of texture. The basal poles are rotated nearly perpendicular to ND by the primary \({{11}\bar{2}{{2}}}\) twin and back to ND through the reorientation of \({{10}\bar{1}{{2}}}\) secondary twin. Both Schmid factor criterion and displacement gradient accommodation are considered to predict the twin-induced texture evolution during TD tension. Kink bands formed by the accumulation of basal 〈a〉 dislocations are also observed in the deformed grain. The activation of other slip systems can deviate the rotation axis and reduce the rotation angle of kink boundary. Besides, the kink boundary with high basal dislocation density obviously hinders the twin transmission and simultaneously can be taken as a preferential nucleation site for \({{11}\bar{2}{{2}}}\) twin.

     

Evaluation of coexisting optic nerve head drusen and glaucoma with optical coherence tomography

OBJECTIVE: Optic nerve head drusen often make evaluation of the nerve head difficult to interpret. In addition, visual field defects are known to occur in patients with optic disk drusen, resembling glaucomatous damage. The authors report two cases of coincident optic nerve head drusen and glaucoma, in which the use of optical coherence tomography (OCT) in evaluating the nerve fiber layer was beneficial. PARTICIPANTS: Two patients with both optic nerve head drusen and glaucoma, one with primary open angle glaucoma, the other with pseudoexfoliation glaucoma were evaluated. Both patients had asymmetric optic disk drusen, with clinically visible drusen only in one eye. INTERVENTION: Ophthalmologic examination, color and red-free photography, automated Humphrey visual field testing and OCT were performed. RESULTS: Nerve fiber layer loss as measured by OCT was found to be greater than expected by the appearance of the optic nerve head and red-free photography, with visual fields consistent with findings in case 1. In case 2, visual fields were full, despite nerve fiber layer thinning seen by OCT and red-free photography. CONCLUSIONS: There can be significant nerve fiber layer thinning in patients with both glaucoma and optic disk drusen, despite the appearance of the optic nerve head in these patients. The cup margin may be obscured by the drusen, giving rise to a falsely full-appearing disk. In such cases, OCT may provide a useful means to quantitatively measure the nerve fiber layer thickness and to aid in the management of these patients by detecting nerve fiber layer thinning earlier than would otherwise be possible.