Poly[[[diaqua­sodium]-μ3-5-carb­oxy-2-ethyl-1H-imidazole-4-carboxyl­ato-κ4 N 3,O 4:O 5:O 5] monohydrate]

In the title complex, {[Na(C7H7N2O4)(H2O)2]·H2O}n, the NaI atom exhibits a distorted octa­hedral geometry and is six-coordinated in an NO5 environment. The equatorial plane is defined by three O atoms and one N atom from two distinct 5-carb­oxy-2-ethyl-1H-imidazole-4-carboxyl­ate (H2EIDC) ligands and one coordinated water mol­ecule, and the apical sites are occupied by one carboxyl O atom from one H2EIDC ligand and one O atom from the other coordinated water mol­ecule. The NaI atoms are linked by H2EIDC ligands, generating an infinite double chain along the a axis. These chains are further connected via O—H⋯O and N—H⋯O hydrogen bonds into a three-dimensional supra­molecular network

Hexaaqua­nickel(II) 4,4′-(1,2-dihy­droxy­ethane-1,2-di­yl)dibenzoate monohydrate

In the title compound, [Ni(H2O)6](C16H12O6)·H2O, the NiII cation is located on a mirror plane and is coordinated by six water mol­ecules, two of which are also located on the mirror plane, in a distorted octa­hedral geometry. The 4,4′-(1,2-dihy­droxy­ethane-1,2-di­yl)dibenzoate anion is centrosymmetric with the mid-point of the central ethane C—C bond located on an inversion center. The uncoordinated water mol­ecule is located on a mirror plane. Extensive O—H⋯O hydrogen bonding is present in the crystal structure

Design and synthesis of TiO2/C nanosheets with a directional cascade carrier transfer

Directed transfer of carriers, akin to excited charges in photosynthesis, in semiconductors by structural design is challenging. Here, TiO2 nanosheets with interlayered sp2 carbon and titanium vacancies are obtained by low-temperature controlled oxidation calcination. The directed transfer of carriers from the excited position to Ti-vacancies to interlayered carbon is investigated and proven to greatly increase the charge transport efficiency. The TiO2/C obtained demonstrates excellent photocatalytic and photoelectrochemical activity and significant lithium/sodium ion storage performance. Further theoretical calculations reveal that the directional excited position/Ti-vacancies/interlayered carbon facilitate the spatial inside-out cascade electron transfer, resulting in high charge transfer kinetics. © 2022 The Royal Society of Chemistry

Protective effect of fasudil hydrochloride against acute renal injury in septicopyemia rats

AbstractObjectiveTo observe the protective effect of fasudil hydrochloride against acute renal injury in septicopyemia rats.MethodsA total of 60 Wister rats were included in the study and divided into control group (n = 10), model group (n = 25) and treatment group (n = 25). Model group and treatment group received intraperitoneal injection of endotoxin (ET) to establish acute renal injury models while the control group only received daily intraperitoneal injection of normal saline 1 mL. Five rats were taken out of model group and treatment group respectively at 1 h (T1), 6 h (T2), 12 h (T3), 24 h (T4) and 48 h (T5), for intraperitoneal injection of ET 30 mg/kg. Treatment group received intraperitoneal injection of fasudil hydrochloride 30 mg/kg 1 h before injection of ET. For three groups, 5 mL blood samples were collected from postcava for determination of serum creatinine and urea nitrogen levels at different time points. Concentrations of serum tumor necrosis factor α and ET-1 were determined by using ELISA. The renal pathologic changes were observed under the microscope.ResultsSerum creatinine levels in both model group and treatment group were significantly higher than control group at T2–T5 (P < 0.05) while the levels in treatment group were significantly lower than control group at T3–T5 (P < 0.05). At T2–T5, blood urea nitrogen levels in model group and treatment group were significantly higher than control group (P < 0.05) while the levels in treatment group were significantly lower than model group at T3–T5 (P < 0.05). Concentrations of serum tumor necrosis factor α in model group and treatment group were significantly higher than control group at T1–T5 (P < 0.05) while the levels in treatment group were significantly lower than model group at T1–T5 (P < 0.05). Serum ET-1 concentrations in model group and treatment group were significantly higher than control group at T1–T5 (P < 0.05) while the levels in treatment group at T1–T4 were significantly lower than model group (P < 0.05). Rats in control group showed no swelling or hyperemia in kidney cells but normal structure and normally arranged renal tubular epithelial cells. Obvious injury was observed in model group at T3 and renal tubular epithelial cells in disorder and at swelling condition, hyperemia and angiectasis in glomerulus, degenerative opacities and vacuolar degeneration, and maximized injury were observed at T4. Injury in renal tissue in treatment group was significantly milder than model group.ConclusionsFasudil hydrochloride has the significantly protective effect against acute renal injury in septicopyemia rats

Knowledge-driven Meta-learning for CSI Feedback

Accurate and effective channel state information (CSI) feedback is a key technology for massive multiple-input and multiple-output systems. Recently, deep learning (DL) has been introduced for CSI feedback enhancement through massive collected training data and lengthy training time, which is quite costly and impractical for realistic deployment. In this article, a knowledge-driven meta-learning approach is proposed, where the DL model initialized by the meta model obtained from meta training phase is able to achieve rapid convergence when facing a new scenario during target retraining phase. Specifically, instead of training with massive data collected from various scenarios, the meta task environment is constructed based on the intrinsic knowledge of spatial-frequency characteristics of CSI for meta training. Moreover, the target task dataset is also augmented by exploiting the knowledge of statistical characteristics of wireless channel, so that the DL model can achieve higher performance with small actually collected dataset and short training time. In addition, we provide analyses of rationale for the improvement yielded by the knowledge in both phases. Simulation results demonstrate the superiority of the proposed approach from the perspective of feedback performance and convergence speed.Comment: arXiv admin note: text overlap with arXiv:2301.1347

On nonhydrostatic coastal model simulations of shear instabilities in a stratified shear flow at high Reynolds number

Author Posting. © American Geophysical Union, 2017. 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: Oceans 122 (2017): 3081–3105, doi:10.1002/2016JC012334.The nonhydrostatic surface and terrain-following coastal model NHWAVE is utilized to simulate a continually forced stratified shear flow in a straight channel, which is a generic problem to test the existing nonhydrostatic coastal models' capability in resolving shear instabilities in the field scale. The resolved shear instabilities in the shear layer has a Reynolds number of about 1.4 × 106, which is comparable to field observed value. Using the standard Smagorinsky closure with a grid size close to the Ozmidov length scale, simulation results show that the resolved energy cascade exceeds 1 order of magnitude and the evolution and turbulent mixing characteristics are predicted well. Two different approaches are used to estimate the turbulent dissipation rate, namely using the resolved turbulent energy spectrum and the parameterized subgrid turbulent dissipation rate, and the predicted results provide the upper and lower bounds that encompass the measured values. Model results show significantly higher turbulence in braids of shear instabilities, which is similar to field observations while both the subgrid turbulent dissipation rate and resolved vorticity field can be used as surrogates for measured high acoustic backscatter signals. Simulation results also reveal that the surface velocity divergence/convergence is an effective identifier for the front of the density current and the shear instabilities. To guide future numerical studies in more realistic domains, an evaluation on the effects of different grid resolutions and subgrid viscosity on the resolved flow field and subgrid dissipation rate are discussed.Office of Naval Research Grant Numbers: N00014-15-1-2612 , N00014-16-1-2948; National Science Foundation Grant Numbers: OCE-1334325 , OCE-1232928; Extreme Science and Engineering Discovery Environment (XSEDE) SuperMIC Grant Number: TG-OCE1000152017-10-1

Surface characterization through shape oscillations of drops in microgravity and 1-g

The goal of these experiments is to determine the rheological properties of liquid drops of single or multiple components in the presence or absence of surface active materials by exciting drops into their quadrupole resonance and observing their free decay. The resulting data coupled with appropriate theory should give a better description of the physics of the underlying phenomena, providing a better foundation than earlier empirical results could. The space environment makes an idealized geometry available (spherical drops) so that theory and experiment can be properly compared, and allows a 'clean' environment, by which is meant an environment in which no solid surfaces come in contact with the drops during the test period. Moreover, by considering the oscillations of intentionally deformed drops in microgravity, a baseline is established for interpreting surface characterization experiments done on the ground by other groups and ours. Experiments performed on the United States Microgravity Laboratory Laboratory (USML-1) demonstrated that shape oscillation experiments could be performed over a wide parameter range, and with a variety of surfactant materials. Results, however, were compromised by an unexpected, slow drop tumbling, some problems with droplet injection, and the presence of bubbles in the drop samples. Nevertheless, initial data suggests that the space environment will be useful in providing baseline data that can serve to validate theory and permit quantitative materials characterization at 1-g

The Photometric System of Tsinghua-NAOC 80-cm Telescope at NAOC Xinglong Observatory

Tsinghua-NAOC (National Astronomical Observatories of China) Telescope (hereafter, TNT) is an 80-cm Cassegrain reflecting telescope located at Xinglong bservatory of NAOC, with main scientific goals of monitoring various transients in the universe such as supernovae, gamma-ray bursts, novae, variable stars, and active galactic nuclei. We present in this paper a systematic test and analysis of the photometric performance of this telescope. Based on the calibration observations on twelve photometric nights, spanning the period from year 2004 to year 2012, we derived an accurate transformation relationship between the instrumental $ubvri$ magnitudes and standard Johnson $UBV$ and Cousins $RI$ magnitudes. In particular, the color terms and the extinction coefficients of different passbands are well determined. With these data, we also obtained the limiting magnitudes and the photometric precision of TNT. It is worthwhile to point out that the sky background at Xinglong Observatory may become gradually worse over the period from year 2005 to year 2012 (e.g., $\sim$21.4 mag vs. $\sim$20.1 mag in the V band).Comment: 12 pages,9 figures, accepted by RA