We developed a new approach to test the single-photon emissions of semiconductor quantum dots (QDs) in the optical communication band. A diamond-anvil cell pressure device was used for blue-shifting ...the 1.3 μm emissions of InAs/GaAs QDs to 0.9 μm for detection by silicon avalanche photodiodes. The obtained g((2))(0) values from the second-order autocorrelation function measurements of several QD emissions at 6.58 GPa were less than 0.3, indicating that this approach provides a convenient and efficient method of characterizing 1.3 μm single-photon source based on semiconductor materials.
River floods are usually featured by a downstream flattening discharge peak whereas a downstream increasing discharge peak is observed at a rate exceeding the tributary discharge during highly ...silt-laden floods (hyperconcentrated floods) in China's Yellow River. It entails a great challenge in the downstream flood defence and the underlying mechanisms need to be unravelled. Previous study on this issue only focuses on one possible mechanism, while the present work aims to reveal the relative importance of bed roughness change and bed erosion in the hyperconcentrated flood. Using a newly developed fully coupled morphodynamic model, we have conducted a numerical study for the 2004 hyperconcentrated flood in the Xiaolangdi-Jiahetan reach of the Lower Yellow River. In order to focus on the physical mechanism and to reduce uncertainty from low-resolution topography data, the numerical modeling was carried out in a schematized 1-D channel of constant width. The basic understanding that bed roughness decreases with concentration at moderate concentrations (e.g. several 10 s to 100 s g L−1) was incorporated by a simple power-law relation between Manning roughness coefficient and sediment concentration. The feedback between the bed deformation and the turbid flow, however, was fully accounted for, in the constituting equations as well as in the numerical solutions. The model successfully reproduced the downstream flood peak increase for the 2004 flood when considering the hyperconcentration-induced bed roughness reduction. As the hyperconcentration lags shortly behind the flood peak, later parts of the flood wave may experience less friction and overtake the wave front, leading to the discharge increase. In comparison, bed erosion is much less important to the discharge increase, at least for hyperconcentrated flood of moderate sediment concentration.
The purpose of this study was to investigate the prevalence and risk factors of dyslipidemia in a rural population of Henan Province, China.
A total of 20 194 participants aged ≥18 years were ...selected randomly by cluster sampling from two townships(towns)in Henan Province from July to August 2007 and July to August 2008. Investigations included questionnaires, anthropometric measurements, fasting plasma glucose, and lipid profile examination at baseline. A total of 16 155 participants were followed up from July to August 2013 and July to October 2014. Overall, 13 869 participants were included in the study, after excluding 2 286 participants with incomplete dyslipidemia follow-up data. Distributions of the characteristics of dyslipidemia were determined, and prevalence was standardized by age according to data of the 2010 Sixth National Population Census. Risk factors for dyslipidemia were analyzed using a logistic regression model after adjusting for sex, age, education level, marital status, and income stat
Nitric oxide (NO) is an active molecule involved in many physiological functions in plants. To characterise the roles of NO in the tolerance of eggplant (Solanum melongena L.) to salt stress, the ...protective effects of exogenous sodium nitroprusside (SNP), a donor of NO, applied at different concentrations (0, 0.05, 0.1, or 0.2 mM), on plant biomass, photosynthesis, and anti-oxidant capacity were evaluated.The application of SNP alleviated the suppression of growth in eggplant under salt stress, as reflected by a higher accumulation of biomass. In parallel with growth, the application of SNP to salt-stressed plants resulted in enhanced photosynthetic parameters such as the net photosynthetic rate (Pn), stomatal conductance (g(s)), transpiration rate (Tr), and intercellular CO2 concentration (Ci), as well as an increased quantum efficiency of PSII (Fv/Fm), efficiency of excitation capture of open PSII centres (Fv/Fm), quantum yield of PSII (ΦPSII) and photochemical quenching coefficient (qP). Furthermore, exogenous SNP also reduced significantly the rate of production of O2•- radicals and the concentrations of malondialdehyde (MDA) and H2O2. It also increased the activities of superoxide dismutase (SOD), guaiacol peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) in eggplant leaves grown under salt stress. The results indicated that the protective effects of NO against salt stress in eggplant seedlings were most likely mediated through improvements in photosynthetic performance and the stimulation of anti-oxidant capacity.
Dysfunctional metabolisms have contributed towards ischemia-reperfusion (I/R) injury. However, the role of remote ischemic preconditioning (RIP) in I/R injury is not well known. The present study ...showed alleviated I/R injury in kidneys treated with RIP.
We utilized GC/MS-based metabolomics to characterize the variation of metabolomes.
Metabolic category using differential metabolites showed the lower percentage of amino acids in I/R group in comparison to RIP+I/R group, confirming the importance of amino acid metabolism in RIP-treated rat kidney. Further, pathway enrichment analysis showed alanine, aspartate and glutamate metabolism to be involved in the beneficial effects of RIP during renal I/R injury. Furthermore, another crucial enrichment pathway is biosynthesis of unsaturated fatty acids. Other vital metabolites detected in independent component analysis (ICA) analysis were d-glucose, lactic acid and cholesterol. The variation tendency of above-mentioned metabolites was overall consistent with the protective nature of RIP.
These findings elicited a viewpoint that metabolic strategy affected by RIP are linked to underlying mechanisms of RIP and highlighted the importance of metabolic strategy against I/R injury.
Near global upper tropospheric concentrations of carbon monoxide (CO), ethane (C2H6) and ethyne (C2H2) from ACE (Atmospheric Chemistry Experiment) Fourier transform spectrometer on board the Canadian ...satellite SCISAT-1 are presented and compared with the output from the Chemical Transport Model (CTM) GEOS-Chem. The retrievals of ethane and ethyne from ACE have been improved for this paper by using new sets of microwindows compared with those for previous versions of ACE data. With the improved ethyne retrieval we have been able to produce a near global upper tropospheric distribution of C2H2 from space. Carbon monoxide, ethane and ethyne concentrations retrieved using ACE spectra show the expected seasonality linked to variations in the anthropogenic emissions and destruction rates as well as seasonal biomass burning activity. The GEOS-Chem model was run using the dicarbonyl chemistry suite, an extended chemical mechanism in which ethyne is treated explicitly. Seasonal cycles observed from satellite data are well reproduced by the model output, however the simulated CO concentrations are found to be systematically biased low over the Northern Hemisphere. An average negative global mean bias of 12% and 7% of the model relative to the satellite observations has been found for CO and C2H6 respectively and a positive global mean bias of 1% has been found for C2H2. ACE data are compared for validation purposes with MkIV spectrometer data and Global Tropospheric Experiment (GTE) TRACE-A campaign data showing good agreement with all of them.
The nature of the glass transition is a fundamental and long-standing intriguing issue in the condensed-matter physics and materials science community. In particular, the structural response by which ...a liquid is arrested dynamically to form a glass or amorphous solid upon approaching its freezing temperature the glass transition temperature (Tg) remains unclear. Various structural scenarios in terms of the percolation theory have been proposed recently to understand such a phenomenon; however, there is still no consensus on what the general percolation entity is and how the entity responds to the sudden slowdown dynamics during the glass transition. In this paper, we demonstrate that one-dimensional local linear ordering (LLO) is a universal structural motif associated with the glass transition for various metallic glasses. The quantitative evolution of LLO with temperature indicates that a percolating LLO network forms to serve as the backbone of the rigid glass solid when the temperature approaches the freezing point, resulting in the frozen-in dynamics accompanying the glass transition. The percolation transition occurs by pinning different LLO networks together, which only needs the introduction of a small number of “joint” atoms between them, and therefore the energy expenditure is very low.
A series of potential PSMA substrates was prepared that explored acidic residues at the P1 position and various chromophores at the P2 position, while keeping the P1′ residue constant as
l-Glu. The ...substrate 4-phenylazobenzoyl-Glu-γ-Glu was found to be proteolyzed most efficiently.
A series of putative dipeptide substrates of prostate-specific membrane antigen (PSMA) was prepared that explored α- and β/γ-linked acidic residues at the P1 position and various chromophores at the P2 position, while keeping the P1′ residue constant as
l-Glu. Four chromophores were examined, including 4-phenylazobenzoyl, 1-pyrenebutyryl, 9-anthracenylcarboxyl-γ-aminobutyryl, and 4-nitrophenylbutyryl. When evaluating these chromophores, it was found that a substrate containing 4-phenylazobenzoyl at the P2 position was consumed most efficiently. Substitution at the P1 position with acidic residues showed that only γ-linked
l-Glu and
d-Glu were recognized by the enzyme, with the former being more readily proteolyzed. Lastly, binding modes of endogenous substrates and our best synthetic substrate (4-phenylazobenzoyl-Glu-γ-Glu) were proposed by computational docking studies into an X-ray crystal structure of the PSMA extracellular domain.
BACKGROUND: Varied clinical outcomes of assisted hatching (AH) have been reported. We attempt to investigate whether the size of the zona opening created by AH is adequate for blastocyst hatching, ...and, if not, set up a new method to improve it. METHODS: A new AH technique, long zona dissection (LZD), was established, and experiments were performed to compare the effects of different sizes of zona opening on complete hatching of blastocysts in mouse and human embryos in vitro. RESULTS: The LZD technique can create a long zona slit on early embryos, even blastocysts, with the slit size beyond two-thirds of zona diameter. Compared with three-dimensional partial zona dissection, LZD can significantly enhance the hatching speed and the rate of complete hatching of mouse blastocysts (93.9%). All (100%) human blastocysts completely hatched following LZD; however, when the slit size after AH was about two-fifths of zona diameter, more of the larger inner cell masses (ICM) became trapped by the zona opening during hatching than the smaller ICM (53.3 versus 12.5%, P=0.01). CONCLUSIONS: Zona opening of moderate size following AH is inadequate for the completion of blastocyst hatching in vitro; in some cases, however, it can be significantly improved by LZD.
We report the observation of gravitational waves from a binary-black-hole coalescence during the first two weeks of LIGO’s and Virgo’s third observing run. The signal was recorded on April 12, 2019 ...at05∶30∶44 UTC with a network signal-to-noise ratio of 19. The binary is different from observations during the first two observing runs most notably due to its asymmetric masses: a∼30M⊙black hole merged with a ∼8M⊙black hole companion. The more massive black hole rotated with a dimensionless spin magnitude between 0.22 and 0.60 (90% probability). Asymmetric systems are predicted to emit gravitational waves with stronger contributions from higher multipoles, and indeed we find strong evidence for gravitational radiation beyond the leading quadrupolar order in the observed signal. A suite of tests performed onGW190412 indicates consistency with Einstein’s general theory of relativity. While the mass ratio of this system differs from all previous detections, we show that it is consistent with the population model of stellar binary black holes inferred from the first two observing runs.
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