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91.
92.
The sale of botanical dietary supplements in the United States is on the rise. However, limited studies have been conducted on the safety of these supplements. There are reports on the presence of undesired metals in some of the botanical dietary supplements. In this study, echinacea, garlic, ginkgo, ginseng, grape seed extract, kava kava, saw palmetto, and St. John's wort supplements manufactured by Nature's Way, Meijer, GNC, Nutrilite, Solaray, Sundown and Natrol, have been analyzed for lead, mercury, cadmium, arsenic, uranium, chromium, vanadium, copper, zinc, molybdenum, palladium, tin, antimony, thallium, and tungsten using inductively coupled plasma mass spectrometry. All samples were devoid of mercury contamination. Results indicated that the botanical supplements analyzed did not contain unacceptable concentrations of these metals. These supplements were also evaluated for microbial contamination, and most samples analyzed showed the presence of bacteria or fungi or both. Microbes were not counted nor were microbial counts determined in these samples. 相似文献
93.
Pandey R. A. Malhotra S. Rajvaidya A. S. Sharma S. Peshwe S. Raman V. K. Bal A. S. 《Water, air, and soil pollution》2003,142(1-4):243-260
Gases and suspended particulate matter are sampled and measured in situ at different sites within the city of Madrid to determinethe air pollution in the city. Lead concentrations in air are also determined. The information needed to assess levels of contaminants is obtained combining several analytical techniques,which provide real time concentration data of particles andgases. Particulate matter (PM), SO2, CO, O3, NOx,NO2, CH4, total hydrocarbons and Pb were measured. Concentrations of pollutants are averaged over periods of hours,days, months and years. Variations of contaminant concentrationsin the last years are presented. Spatial and temporal distribution follows that of the traffic, the main source of pollution in Madrid City. Some specific measurements were carriedout to understand the influence of traffic emissions at themeasured site. Further, all measured concentrations never exceeded the European Union Directives. 相似文献
94.
Stability constants of complexes of four divalent metal ions viz. Cu2+, Zn2+, Mn2+ and Ca2+ with humic (HA) and fulvic acids (FA) at pH values of 7 and 8 were determined. The log K (logarithm of the stability constant) ranged from 3.09 to 7.77 and from 2.22 to 5.98 for metal-humic and metal fulvic acid complexes, respectively. Sequentially, the order of stability constants were as follows: Cu> Ca> Mn> Zn and Cu> Ca> Zn> Mn for metal -HA and metal-FA complexes, respectively, indicating a higher degree of complexation with Cu metal ion. 相似文献
95.
96.
Crustal temperatures within collisional orogens are anomalously high compared with temperatures at comparable depths in stable continents, which is evidence of thermal processes that are fundamental to orogenesis. These temperatures can be explained by the redistribution of crust enriched in heat-producing elements through the accretion of crust from the down-going plate to the upper plate and surface erosion. With the use of geologically reasonable rates, the model results predict high temperatures (over 600°C) and inverted upper-plate geotherms (about 100°C over 20 kilometers) at shallow depths (20 to 40 kilometers) by 25 to 35 million years after collision. This study emphasizes the interdependence of deformational, surficial, and thermal processes. 相似文献
97.
Quantized vortices play a key role in superfluidity and superconductivity. We have observed the formation of highly ordered vortex lattices in a rotating Bose-condensed gas. These triangular lattices contained over 100 vortices with lifetimes of several seconds. Individual vortices persisted up to 40 seconds. The lattices could be generated over a wide range of rotation frequencies and trap geometries, shedding light on the formation process. Our observation of dislocations, irregular structure, and dynamics indicates that gaseous Bose-Einstein condensates may be a model system for the study of vortex matter. 相似文献
98.
Selvakumar Raman Kalia Pritam Manjunathagowda Dalasanuru Chandregowda Raje R. S. 《Genetic Resources and Crop Evolution》2022,69(7):2413-2423
Genetic Resources and Crop Evolution - The results of the inheritance study revealed that the purple root epiderm (Pe) and cortex (Pcx) colour were dominant over the yellow colour of epiderm (ye)... 相似文献
99.
The importance of demographic niches to tree diversity 总被引:1,自引:0,他引:1
Condit R Ashton P Bunyavejchewin S Dattaraja HS Davies S Esufali S Ewango C Foster R Gunatilleke IA Gunatilleke CV Hall P Harms KE Hart T Hernandez C Hubbell S Itoh A Kiratiprayoon S Lafrankie J de Lao SL Makana JR Noor MN Kassim AR Russo S Sukumar R Samper C Suresh HS Tan S Thomas S Valencia R Vallejo M Villa G Zillio T 《Science (New York, N.Y.)》2006,313(5783):98-101
Most ecological hypotheses about species coexistence hinge on species differences, but quantifying trait differences across species in diverse communities is often unfeasible. We examined the variation of demographic traits using a global tropical forest data set covering 4500 species in 10 large-scale tree inventories. With a hierarchical Bayesian approach, we quantified the distribution of mortality and growth rates of all tree species at each site. This allowed us to test the prediction that demographic differences facilitate species richness, as suggested by the theory that a tradeoff between high growth and high survival allows species to coexist. Contrary to the prediction, the most diverse forests had the least demographic variation. Although demographic differences may foster coexistence, they do not explain any of the 16-fold variation in tree species richness observed across the tropics. 相似文献