The flow behavior of two commercial liquid crystalline polymers (LCPs), trade name Vectra B 950 and Vectra L 950 supplied by Ticona, was investigated using a capillary rheometer with a special double slit die. The pressure drops in convergent and divergent wedge passage between the two slit sections, which are influenced by the curvature strains in nematic melts, were determined and compared with the pressure drops of a conventional polystyrene (PS) with flexible polymer chains. Furthermore the extensional viscositiy was determined from the pressure drop in convergent wedge passage. The development of the shear induced texture as a function of shear rate was investigated by use of a rapidly coolable double slit die with the same gap design as the double slit die used for viscosity measurement. The structural analysis was performed using polarized light microscopy.
In this expository article, we provide a unified version of the literature on certain aspects of cumulants of infinitely divisible distributions. In view of the spectral representations corresponding to the distributions referred to, with appropriate modifications to standard arguments, it follows that the cumulants of these distributions possess some nice features. Giving several illustrative examples, we attempt to explain as to what these mean. Although the emphasis of the paper is on univariate distributions, we briefly touch upon the multivariate case to verify whether this latter case has something new to offer to us on the subject.
Measurement of the amount of oxidative damage to DNA is one tool that can be used to estimate the beneficial effect of diet on the prevention of colon carcinogenesis. The FLARE assay is a modification of the single-cell gel electrophoresis (Comet) assay, and provides a measure of the 8OHdG adduct in the cells. In this paper, we present two innovations to the existing methods of analysis. The first one is related to the FLARE assay itself. We describe automated image analysis techniques that can be expected to measure oxidative damage faster, reproducibly, with less noise, and hence achieve greater statistical power. The proposed technique is compared to an existing technique, which was more manual and thus slower. The second innovation is our statistical analysis: we exploit the shape of FLARE intensity histograms, and show statistically significant diet effects in the duodenum. Previous analyses of this data concentrated on simple summary statistics, and found only marginally statistically significant diet effects. With the new imaging method and measure of oxidative damage, we show cells in the duodenum exposed to fish oil as having more oxidative damage than cells exposed to corn oil.
Severe anemia is common among children infected with human immunodeficiency virus (HIV). The choice of antiretroviral (ART) regimen needs careful consideration. No information is available regarding the initial ART regimens used in the Asia-Pacific region and the rate of switch of ART regimens in HIV-infected children with severe anemia.
To study the initial ART regimens and the rate of switch of ART regimens used during the first 36 months in HIV-infected children with severe anemia and to evaluate their clinical and laboratory outcomes.
We analyzed regional cohort data of 130 Asian children aged <18 years with baseline severe anemia (hemoglobin <7.5 g/dl) who started antiretroviral therapy (ART) between January 2003 and September 2013.
At ART initiation, median age was 3.5 years old (interquartile range (IQR) 1.7 to 6.3) and median hemoglobin was 6.7 g/dL (IQR 5.9-7.1, range 3.0-7.4). Initial ART regimens included stavudine (85.4%), zidovudine (13.8%), and abacavir (0.8%). In 81 children with available hemoglobin data after 6 months of ART, 90% recovered from severe anemia with a median hemoglobin of 10.7 g/dL (IQR 9.6-11.7, range 4.4-13.5). Those starting AZT-based ART had a mortality rate of 10.8 (95% confidence interval (CI) 4.8-23.9) per 100 patient-years compared to 2.7 (95% CI 1.6-4.6) per 100 patient-years among those who started d4T-based ART.
With the phase-out of stavudine, age-appropriate non-zidovudine options are needed for younger Asian children with severe anemia.