3,134 publications from this institution
A preparation of crude polysaccharides (TPS) was isolated from Camellia sinensis by precipitation and ultrafiltration. TPS1, TPS2, and TPS3 had molecular weights of 240, 21.4, and 2.46 kDa, respectively. The radical scavenging activities of TPS were evaluated by DPPH free radical, hydroxyl radical and superoxide radical scavenging. These results revealed that TPS exhibited strong radical scavenging activity in a concentration-dependent manner. TPS3 with lowest molecular weight showed a higher radical scavenging activity.
A non-probabilistic selection of 100 Cuban patients at different stages of HIV infection, according to the revised classification of the Centers for Disease Control and Prevention of 1987, was made from a set of 130 persons with serologically-confirmed HIV infection. Clinical and epidemiological information about each case was collected and peripheral blood samples were taken to detect HIV-1 p24 antigen. The frequency of p24 antigenemia detection and concentration were correlated with available clinical and epidemiological data. P24 antigenemia was significantly more frequent in AIDS patients. No difference was found between the type of opportunistic diseases diagnosed in the group of patients with detectable p24 antigen and the group that was negative to antigen presence; although in the group with antigenemia concentrations over 100 pg/ml, more than one AIDS-related disease was often diagnosed simultaneously. A history of sexual intercourses with several persons who had been infected with HIV was much more frequent in patients with antigenemia, and it was associated with a shorter time elapsed from the probable date of infection to the date of their classification as AIDS patients. These results were compared with the literature review information.
Organic food is progressively boosting the market and becoming more attractive to consumers, who usually feel more confident about these products because of their safer, healthier, and more eco-friendly characteristics when compared to conventional agriculture products [...]
Abstract The sensitivity of localized surface plasmon resonances with respect to changes in the refractive index of the surrounding medium is measured for small (< 60 nm side length) and large (ca. 150 nm side length) regular gold nanodecahedra (pentagonal bipyramids), and compared to rigorous solutions of Maxwell's equations for bicones based upon the boundary element method (BEM). Small particles are prepared through ultrasound‐induced reduction of HAuCl 4 by N , N ‐dimethylformamide (DMF) on presynthesized penta‐twinned Au seeds, whereas large decahedra are grown using smaller ones as seeds. Excellent agreement between experimental and calculated spectra is found for dispersions and monolayers of particles in different solvents, as well as for the effect of uniform silica layers of various thicknesses grown on them. These results are expected to be useful for the development of novel biosensors.
<title>Abstract</title> Recent studies have shown the ubiquity of pleiotropy for variants affecting human complex traits. These studies also show that rare variants tend to be less pleiotropic than common ones, suggesting that purifying natural selection acts against highly pleiotropic variants of large effect. Here we investigate the mean frequency, effect size and recombination rate associated with pleiotropic variants, and focus particularly on whether highly pleiotropic variants are enriched in regions with putative strong background selection. We evaluate variants for 41 human traits using data from the NHGRI-EBI GWAS Catalog, as well as data from other three studies. Our results show that variants involving a higher degree of pleiotropy tend to be more common, have larger mean effect sizes, and contribute more to heritability than variants with a lower degree of pleiotropy. Using data from four different studies, we show that more pleiotropic variants are enriched in genome regions with stronger background selection than less pleiotropic variants. Thus, we conclude that even though highly pleiotropic variants found so far have larger average effect sizes and frequencies than less pleiotropic ones, they are likely to be subjected to stronger background selection.
Due to recent regulations encouraging the reduction of single-use plastic waste, compostable plastics are replacing polyethylene (PE) for applications in the form of thin films. Seven commercial brands of compostable bags and three brands of PE bags (conventional, oxodegradable and recycled), as well as their corresponding resins, were assessed in terms of major components of the polymeric matrix, qualitative and quantitative composition in additives of bags and their leachates, and ecotoxicological effects on test species representative of the main marine taxa, namely microalgae, copepods, sea-urchin embryos, bivalves and fish. Polybutylene-adipate-terephthalate (PBAT), an oil-based polymer, was the main component of all compostable bags analysed, and most of them also included in their composition polylactic-acid (PLA) and starch. Compostable bags showed a higher number of chemical additives than conventional PE bags, and generally higher concentrations of phthalate plasticizers and organophosphate flame retardants. This includes chemicals registered in the EU as exhibiting acute and chronic aquatic toxicity levels 1 and 2. Following standard procedures for plastic leachates, no effects of any product were found on microalgae and fish larva, but bioplastics consistently showed a higher short term aquatic toxicity to marine invertebrates compared to PE items. None of the toxicity levels found though support concerning effects at environmentally relevant plastic densities. Remarkably higher levels of some metals were found in recycled PE compared to first-use conventional PE bags. In conclusion, based on these findings, compostable bags cannot be considered chemically or ecotoxicologically safer products than PE bags.
