247 research outputs found

    Epitaxial hetero-structure of CdSe/TiO2 nanotube arrays with PEDOT as hole transfer layer for photoelectrochemical hydrogen evolution

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    The photocatalytic decomposition of water is believed to be able to help mitigate the crisis of fossil fuel depletion. However, the photocatalytic hydrogen production remains challenge to obtain high and stable photoconversion efficiency. Here we report an epitaxial hetero-structure of CdSe/TiO2 nanotube arrays as efficient photo-anodes via simple room-temperature, low-cost electrochemical deposition. With the help of the similar d spacing with TiO2, CdSe sensitization layer is epitaxially grown on the tube wall of the TiO2 nanotubes, resulting in an ideal coherent grain boundary and single crystal growth. The resultant photo-anode produces 30% more photocurrent than those samples without coherent grain boundary. Notably, the especial epitaxial hetero-structure is beneficial to decrease the recombination site and accelerate the separation of photogenerated electron-hole pairs. Furthermore, an ultrathin PEDOT surface layer was developed on the epitaxial hetero-structure of CdSe/TiO2 nano-tube arrays in which it functions as both a physical passivation barrier and a hole transfer layer. As a result, significantly enhanced photocurrent density and substantially better stability have been achieved. This methodology may be providing a new pathway of epitaxial growth for preparing the heterogeneous junction materials which have similar d spacing

    A low-cost X-ray-transparent experimental cell for synchrotron-based X-ray microtomography studies under geological reservoir conditions

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    A new modular X-ray-transparent experimental cell enables tomographic investigations of fluid rock interaction under natural reservoir conditions (confining pressure up to 20 MPa, pore fluid pressure up to 15 MPa, temperature ranging from 296 to 473 K). The portable cell can be used at synchrotron radiation sources that deliver a minimum X-ray flux density of 109 photons mm−2s−1in the energy range 30–100 keV to acquire tomographic datasets in less than 60 s. It has been successfully used in three experiments at the bending-magnet beamline 2BM at the Advanced Photon Source. The cell can be easily machined and assembled from off-the-shelf components at relatively low costs, and its modular design allows it to be adapted to a wide range of experiments and lower-energy X-ray sources.</jats:p

    Experimental evidence for melt partitioning between olivine and orthopyroxene in partially molten harzburgite

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    Author Posting. © American Geophysical Union, 2016. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Solid Earth 121 (2016): 5776–5793, doi:10.1002/2016JB013122.Observations of dunite channels in ophiolites and uranium series disequilibria in mid-ocean ridge basalt suggest that melt transport in the upper mantle beneath mid-ocean ridges is strongly channelized. We present experimental evidence that spatial variations in mineralogy can also focus melt on the grain scale. This lithologic melt partitioning, which results from differences in the interfacial energies associated with olivine-melt and orthopyroxene-melt boundaries, may complement other melt focusing mechanisms in the upper mantle such as mechanical shear and pyroxene dissolution. We document here lithologic melt partitioning in olivine-/orthopyroxene-basaltic melt samples containing nominal olivine to orthopyroxene ratio of 3 to 2 and melt fractions of 0.02 to 0.20. Experimental samples were imaged using synchrotron-based X-ray microcomputed tomography at a resolution of 700 nm per voxel. By analyzing the local melt fraction distributions associated with olivine and orthopyroxene grains in each sample, we found that the melt partitioning coefficient, i.e., the ratio of melt fraction around olivine to that around orthopyroxene grains, varies between 1.1 and 1.6. The permeability and electrical conductivity of our digital samples were estimated using numerical models and compared to those of samples containing only olivine and basaltic melt. Our results suggest that lithologic melt partitioning and preferential localization of melt around olivine grains might play a role in melt focusing, potentially enhancing average melt ascent velocities.National Science Foundation Grant Numbers: 1250338, 1551300; Basic Energy Sciences Grant Number: DEFG0207ER15916; Advanced Photon Source Grant Number: DE-AC02-06CH113572017-02-2

    Diethyl 4,6-diacetamido­isophthalate

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    In the title compound, C16H20N2O6, two intra­molecular N—H⋯O hydrogen bonds occur, in which the carbonyl O atoms of the ethyl acetate groups serve as the acceptor atoms; both motifs generate S(6) rings. In the crystal, mol­ecules are linked by weak C—H⋯O links (with the acceptor O atoms part of the amide groups), generating [001] chains

    Original Article Correlation of rs1799793 polymorphism in ERCC2 and the clinical response to platinum-based chemotherapy in patients with triple negative breast cancer

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    Abstract: Background: Polymorphisms of DNA repair genes may affect the repair capacity of DNA damages and cause different responses towards chemotherapy. Excision repair cross-complementing group 2 (ERCC2) plays an important role in the nucleotide excision repair. Objectives: The aim of this study was to investigate the association between ERCC2 single nucleotide polymorphisms (SNPs) and the response to platinum-based chemotherapy among patients with triple negative breast cancer. Methods: In total, 60 triple negative breast cancer patients treated with platinum-based chemotherapy were studied. The clinical, pathological and treatment data of them were collected. Sequenom&apos;s MassARRAY system was used in the detection of the SNPs of ERCC2. Finally, the association between genotypes and different clinical responses among patients was analyzed. All of the patients received a platinum-based chemotherapy for 4 cycles in median and achieved an overall response rate of 66.7%, showing a comparative good response towards platinum-based chemotherapy among triple negative breast cancer. Fifty-three of the 60 patients had got the results of ERCC2 rs1799793 polymorphisms after MassARRAY detection. Results: The proportion of GG genotype and GA genotype was 81.1% and 18.9% respectively. The response rate of the rs1799793 GG genotype group was 69.8%, while the GA genotype group only had a response rate of 30.0%. It turned out that the GG genotype was associated with better response towards platinum-based chemotherapy (P=0.030). Conclusions: ERCC2 rs1799793 polymorphism may be associated with the clinical sensitivity of platinum-based chemotherapy and could be a potential predictive biomarker for triple negative breast cancer patients treated with platinum compounds

    Experimental evidence of reaction-induced fracturing during olivine carbonation.:Fracturing during olivine carbonation

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    Mineral carbonation, a process that binds CO2 in the form of carbonates by silicate weathering, is widespread on the Earth's surface. Because of the abundance of silicate rocks and the permanence of the carbonated solids, sequestering CO2 via mineral carbonation has generated lots of interests. However, it is unclear how the fluid-rock reaction proceeds to completion in spite of an increasing solid volume. We conducted a mineral carbonation experiment in which a sintered olivine aggregate reacted with a sodium bicarbonate solution at reservoir conditions. Time-resolved synchrotron X-ray microtomographic images show cracks in polygonal patterns arising in the surface layers and propagating into the interior of the olivine aggregate. The nanotomography data reveal that the incipient cracks intersect at right angles. We infer that stretching due to nonuniform volume expansion generates polygonal cracking of the surfaces. Our data shed new lights on the processes that control hydration and carbonation of peridotite

    CcGSDMEa functions the pore-formation in cytomembrane and the regulation on the secretion of IL-lβ in common carp (Cyprinus carpio haematopterus)

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    GSDME is the only direct executor of caspase-dependent pyroptosis in both canonical and non-canonical inflammasomes known to date in fish, and plays an important role in anti-bacterial infection and inflammatory response. In order to determine the regulation of GSDMEa on antibacterial infection in innate immune response, the CcGSDMEa gene in common carp (Cyprinus carpio haematopterus) was first identified and characterized, and then its function related to immune defense was investigated. Our results showed that the expressions of CcGSDMEa at the mRNA and protein levels were both significantly increased after Aeromonas hydrophila intraperitoneal infection at the early stage than that in the control group. We found that CcGSDMEa could be cleaved by inflammatory caspase (CcCaspase-1b) and apoptotic caspases (CcCaspase-3a/b and CcCaspase-7a/b). Interestingly, only the CcGSDMEa-NT (1-252 aa) displayed bactericidal activity to Escherichia coli and could punch holes in the membrane of HEK293T cells, whereas CcGSDMEa-FL (1-532 aa) and CcGSDMEa-CT (257-532 aa) showed no above activity and pore-forming ability. Overexpression of CcGSDMEa increased the secretion of CcIL-1β and the release of LDH, and could reduce the A. hydrophila burdens in fish. On the contrary, knockdown of CcGSDMEa reduced the secretion of CcIL-1β and the release of LDH, and could increase the A. hydrophila burdens in fish. Taken together, the elevated expression of CcGSDMEa was a positive immune response to A. hydrophila challenge in fish. CcGSDMEa could perform the pore-formation in cell membrane and the regulation on the secretion of IL-lβ, and further regulate the bacterial clearance in vivo. These results suggested that CcGSDMEa played an important role in immune defense against A. hydrophila and could provide a new insight into understanding the immune mechanism to resist pathogen invasion in teleost

    Seaweed polysaccharide relieves hexavalent chromium-induced gut microbial homeostasis

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    Heavy metals released in the environment pose a huge threat to soil and water quality, food safety and public health. Additionally, humans and other mammals may also be directly exposed to heavy metals or exposed to heavy metals through the food chain, which seriously threatens the health of animals and humans. Chromium, especially hexavalent chromium [Cr (VI)], as a common heavy metal, has been shown to cause serious environmental pollution as well as intestinal damage. Thus, increasing research is devoted to finding drugs to mitigate the negative health effects of hexavalent chromium exposure. Seaweed polysaccharides have been demonstrated to have many pharmacological effects, but whether it can alleviate gut microbial dysbiosis caused by hexavalent chromium exposure has not been well characterized. Here, we hypothesized that seaweed polysaccharides could alleviate hexavalent chromium exposure-induced poor health in mice. Mice in Cr and seaweed polysaccharide treatment group was compulsively receive K2Cr2O7. At the end of the experiment, all mice were euthanized, and colon contents were collected for DNA sequencing analysis. Results showed that seaweed polysaccharide administration can restore the gut microbial dysbiosis and the reduction of gut microbial diversity caused by hexavalent chromium exposure in mice. Hexavalent chromium exposure also caused significant changes in the gut microbial composition of mice, including an increase in some pathogenic bacteria and a decrease in beneficial bacteria. However, seaweed polysaccharides administration could ameliorate the composition of gut microbiota. In conclusion, this study showed that seaweed polysaccharides can restore the negative effects of hexavalent chromium exposure in mice, including gut microbial dysbiosis. Meanwhile, this research also lays the foundation for the application of seaweed polysaccharides

    Projected increases in emissions of high global warming potential fluorinated gases in China

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    China is the largest greenhouse gas emitter in the world and has committed to mitigating global warming through achieving carbon neutrality by 2060. However, detailed information on China’s historical and projected emissions of fluorinated greenhouse gases, with high global warming potentials, is lacking. Here we establish a comprehensive and up-to-date inventory of China’s fluorinated greenhouse gas emissions and find that they show an accelerating growth rate, increasing from 5.5 to 221 million tons CO2-equivalent per year from 1990 to 2019. China has become the world’s largest emitter of fluorinated greenhouse gases and contributed 93% of the global emission increase during the period 1990−2019. We find that total emissions of fluorinated greenhouse gases from China are projected to increase to 506–1356 million tons CO2-equivalent per year in 2060 if there is no regulation, which is larger than the projected CO2 emissions under China’s carbon neutrality commitment for 2060

    Update of TTD: Therapeutic Target Database

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    Increasing numbers of proteins, nucleic acids and other molecular entities have been explored as therapeutic targets, hundreds of which are targets of approved and clinical trial drugs. Knowledge of these targets and corresponding drugs, particularly those in clinical uses and trials, is highly useful for facilitating drug discovery. Therapeutic Target Database (TTD) has been developed to provide information about therapeutic targets and corresponding drugs. In order to accommodate increasing demand for comprehensive knowledge about the primary targets of the approved, clinical trial and experimental drugs, numerous improvements and updates have been made to TTD. These updates include information about 348 successful, 292 clinical trial and 1254 research targets, 1514 approved, 1212 clinical trial and 2302 experimental drugs linked to their primary targets (3382 small molecule and 649 antisense drugs with available structure and sequence), new ways to access data by drug mode of action, recursive search of related targets or drugs, similarity target and drug searching, customized and whole data download, standardized target ID, and significant increase of data (1894 targets, 560 diseases and 5028 drugs compared with the 433 targets, 125 diseases and 809 drugs in the original release described in previous paper). This database can be accessed at http://bidd.nus.edu.sg/group/cjttd/TTD.asp
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