Search

BACKGROUND The groundwater in Xingguo County is rich in metasilicic acid, but the research on the endowment characteristics and genetic mechanism of mineral water resources is relatively weak, which restricts the development of the mineral water industry in Xingguo County to some extent. Research on the chemical characteristics and health functions of metasilicate mineral water in the county provides basic support for the development of the local mineral water industry and the implementation of a revitalization strategy. OBJECTIVES To summarize the distribution characteristics of metasilicate mineral water in Xingguo County and evaluate its health function. METHODS Mathematical statistics, water chemistry analysis, ion ratio and other analytical methods were used to study the distribution, water chemistry characteristics, genesis and material sources of potential metasilicate mineral water in Xingguo County, and its health function based on sensory index and health index was evaluated. RESULTS Potential metasilicate mineral water was mainly distributed in the area below 400m above sea level, and it was distributed primarily in a magmatic rock fissure water-bearing rock formation, a clastic rock pore fissure water-bearing rock formation and a metamorphic rock fissure water-bearing rock formation. In the investigated water samples of these three types of water-bearing rock formations, the proportion of potential metasilicate mineral water was 48.5%, 45.7% and 29.6%, respectively. The metasilicic acid content of potential metasilicate mineral water was mostly between 32 and 40mg/L, mainly from the hydrolysis of silicate minerals. The enrichment of metasilicic acid was caused by solution filtration in the metamorphic rock and magmatic rock fracture water-bearing formation area, and was jointly affected by solution filtration and cation alternating adsorption in the clastic rock pore fracture water-bearing formation area. The potential metasilicate mineral water in the magmatic rock fracture water-bearing group area had the best taste, and the deep clastic rock pore water bearing group area had a relatively high health index. CONCLUSIONS The results of this study suggest that the target area of mineral water exploration and development in Xingguo County should be in magmatic rock fissure water-bearing rock formation areas and deep clastic rock pore fissure water-bearing rock formation areas. The research results provide reference for revealing the value and function of metasilicate mineral water resources in Xingguo County.

Aconitine hydrolysis is deemed to be the guarantee for the safe application of Aconitum phytomedicine. Studies have suggested that hydrolysates of aconitine not only include benzoylaconitine and aconine, but other hydrolysates. Moreover, these hydrolysates maybe have a mutual transformation relationship, which has not been confirmed. Herein, hydrolysates of aconitine and their mutual transformation relationship were studied by the theoretical quantum chemistry, UPLC-Q-TOF-MS, the separation and identification of target products, etc. Then the toxicity of its hydrolysates was evaluated. The results demonstrate that the probability is the same for aconitine hydrolysis to pyroaconitine and benzoylaconitine, but they are difficult to convert to each other. Aconitine hydrolysis has three independent hydrolysis pathways, 1) to indaconitine, 2) to benzoylaconitine, and aconine, 3) to pyroaconitine and to 16-epi-pyroaconine. The result of embryotoxicity evaluation on zebrafish was aconitine > indaconitine > benzoylaconitine > α-pyroaconitine > β- pyroaconitine > aconine > 16-epi-pyroaconine. In conclusion, aconitine have three independent hydrolysis pathways and the hydrolysates of different pathways cannot be transformed into each other. Pyroaconitine is a hydrolysate of aconitine except for benzoylaconitine, and its toxicity is lower than benzoylaconitine. More importantly, it clarifies the long-standing debate and provides scientific evidence for the processing and detoxification of Aconitum phytomedicine.

The BRCA1-BARD1 tumour suppressor is an E3 ubiquitin ligase necessary for the repair of DNA double-strand breaks by homologous recombination.sup.1-10. The BRCA1-BARD1 complex localizes to damaged chromatin after DNA replication and catalyses the ubiquitylation of histone H2A and other cellular targets.sup.11-14. The molecular bases for the recruitment to double-strand breaks and target recognition of BRCA1-BARD1 remain unknown. Here we use cryo-electron microscopy to show that the ankyrin repeat and tandem BRCT domains in BARD1 adopt a compact fold and bind to nucleosomal histones, DNA and monoubiquitin attached to H2A amino-terminal K13 or K15, two signals known to be specific for double-strand breaks.sup.15,16. We further show that RING domains.sup.17 in BRCA1-BARD1 orient an E2 ubiquitin-conjugating enzyme atop the nucleosome in a dynamic conformation, primed for ubiquitin transfer to the flexible carboxy-terminal tails of H2A and variant H2AX. Our work reveals a regulatory crosstalk in which recognition of monoubiquitin by BRCA1-BARD1 at the N terminus of H2A blocks the formation of polyubiquitin chains and cooperatively promotes ubiquitylation at the C terminus of H2A. These findings elucidate the mechanisms of BRCA1-BARD1 chromatin recruitment and ubiquitylation specificity, highlight key functions of BARD1 in both processes and explain how BRCA1-BARD1 promotes homologous recombination by opposing the DNA repair protein 53BP1 in post-replicative chromatin.sup.18-22. These data provide a structural framework to evaluate BARD1 variants and help to identify mutations that drive the development of cancer. The authors elucidate the mechanisms for the ubiquitylation specificity and recruitment of the ubiquitin ligase complex BRCA1-BARD1 to damaged DNA within chromatin to facilitate homologous recombination., Author(s): Qi Hu [sup.1] , Maria Victoria Botuyan [sup.1] , Debiao Zhao [sup.1] , Gaofeng Cui [sup.1] , Elie Mer [sup.1] , Georges Mer [sup.1] [sup.2] Author Affiliations: (1) Department [...]

Observations have indicated that compared to the six decades before 1960, the frequency of dry summers in the U.S. Great Plains was lowered by 20% in the six decades after 1960. In the meantime, there was a sharp increase in the recent six decades in both the rate and coverage of groundwater irrigation in the region repeated every summer for agricultural production. The potential effect of irrigation on the changes of growing season precipitation in the Great Plains is examined in this study using models from the perspective of regional circulation and climate, broadened from prior studies of irrigation effects focused on changes of specific weather elements. As the first step, the dry year of 2012 is used in this case study to minimize wet circulation impacts and also the possibility for the irrigation effect being skewed by decadal variations/trends in climate itself. It is found that massive irrigation in the Great Plains does not alter the frequency and duration of individual precipitation events. Irrigation does, however, modify the regional thermodynamic properties of the atmosphere enough to amplify the precipitation rate and amount in most weather events. In addition to these direct effects, irrigation further influences large-scale circulations, especially the Great Plains low-level jet (GPLLJ) and, through them, indirectly affects the growing season climate in the irrigated region. Analysis of physical processes explains the weakening of the GPLLJ and reduction of its northward moisture flux by irrigation. Budget analysis shows that this negative indirect effect of irrigation on moisture and precipitation is surpassed by the direct effect in the irrigated region, resulting in a net increased precipitation rate for individual rainfall events. [ABSTRACT FROM AUTHOR]

Aluminide coatings were prepared by chemical vapor deposition (CVD) method on Ni-based superalloy Mar-M247 to improve the corrosion resistance. The Na2SO4-induced hot corrosion behavior of Mar-M247 with and without aluminide coating was investigated at varying temperatures. The results revealed that the substrate underwent relatively mild corrosion attack at temperatures below the Na2SO4 melting point, but extremely severe corrosion attack above it. The aluminide coating significantly improved the corrosion resistance of the substrate, with the formation of Al2O3 scale during corrosion. The effects of both solid and molten Na2SO4 on hot corrosion resistance of Mar-M247 alloy and its aluminide coating was discussed, as well as the detrimental effect of tungsten on the substrate in 'type I' hot corrosion. [ABSTRACT FROM AUTHOR]

Background: Abdominal aortic aneurysm (AAA) is a potentially fatal vascular disorder with a high mortality rate. It was previously reported that fibroblast growth factor 21 (FGF21) was highly expressed in AAA patients. Nonetheless, its underlying mechanism in AAA progression is unclarified. Methods: Angiotensin II (Ang-II) was used to induce AAA in human aortic vascular smooth muscle cells (HASMCs) and mouse models. Western blotting and RT-qPCR were utilized for measuring protein and RNA levels. Immunofluorescence staining was utilized for detecting LC3B expression in HASMCs. Elastica van Gieson staining was conducted for histological analysis of the abdominal aortas of mice. Results: FGF21 displayed a high level in Ang-II-stimulated HASMCs and AAA mice. FGF21 depletion ameliorated abdominal aorta dilation and Ang-II-triggered pathological changes in mice. FGF21 silencing hindered autophagy and PI3K/AKT/mTOR pathway. Conclusions: FGF21 contributes to AAA progression by enhancing autophagy and activating PI3K/AKT/mTOR pathway. [ABSTRACT FROM AUTHOR]