681 research outputs found

    Tetranuclear Copper(II) Complexes Derived from 5-Bromo-2-((2-(2-hydroxyethylamino)ethylimino)methyl)phenol: Synthesis, Characterization, Crystal Structures and Catalytic Oxidation of Olefins

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    An acetate bridged tetranuclear copper(II) complex, [Cu4L2(μ2-η1:η1-CH3COO)6(CH3OH)2] (1), and a chloride, phenolate and azide co-bridged tetranuclear copper(II) complex, [Cu4L2Cl2(μ-Cl)2(μ1,1-N3)2]2CH3OH (2), where L is the deprotonated form of the Schiff base 5-bromo-2-((2-(2-hydroxyethylamino)ethylimino)methyl)phenol (HL), have been synthesized and characterized by elemental analysis, IR and UV spectra, and single crystal X-ray diffraction. Single crystal X-ray analysis revealed that the Cu atoms in both complexes are in square pyramidal geometry. In complex 1, two [CuL] units and [Cu2(μ2-η1:η1-CH3COO)4] core are linked through two acetate ligands. In complex 2, [Cu2LCl(μ-Cl)] units are linked together by two end-on azido ligands. The Schiff base ligand coordinates to the Cu atoms through four N and O donor atoms. The molecules of both complexes are linked through hydrogen bonds to generate three dimensional networks. The catalytic property of the complexes for epoxidation reactions of some alkenes was studied using tert-butylhydroperoxide as the terminal oxidant under mild conditions in acetonitrile

    N-(9H-Fluoren-9-yl­idene)-4-methyl­aniline

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    In the title compound, C20H15N, the fluorene unit is essentially planar [r.m.s. deviation 0.0334 Å] and the benzene ring bound to the imine N atom bears a methyl group which is nearly coplanar [dihedral angle 0.5 (1)°]. The dihedral angle between the substituent benzene ring and the 9H-fluoren-9-imine unit is 71.1 (3)°. Inter­molecular π–π inter­actions between the benzene rings of adjacent fluorene units [centroid–centroid distance 3.8081 (13) Å] are present in the crystal structure, resulting in a one-dimensional supra­molecular architecture

    Parameter Optimization of a Discrete Scattering Model by Integration of Global Sensitivity Analysis Using SMAP Active and Passive Observations

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    Active and passive microwave signatures respond differently to the land surface and provide complementary information on the characteristics of the observed scenes. The objective of this paper is to explore the synergy of active radar and passive radiometer observations at the same spatial scale to constrain a discrete radiative transfer model, the Tor Vergata (TVG) model, to gain insights into the microwave scattering and emission mechanisms over grasslands. The TVG model can simultaneously simulate the backscattering coefficient and emissivity with a set of input parameters. To calibrate this model, in situ soil moisture and temperature data collected from the Maqu area in the northeastern region of the Tibetan Plateau, interpolated leaf area index (LAI) data from the Moderate Resolution Imaging Spectroradiometer LAI eight-day products, and concurrent and coincident Soil Moisture Active Passive (SMAP) radar and radiometer observations are used. Because this model needs numerous input parameters to be driven, the extended Fourier amplitude sensitivity test is first applied to conduct global sensitivity analysis (GSA) to select the sensitive and insensitive parameters. Only the most sensitive parameters are defined as free variables, to separately calibrate the active-only model (TVG-A), the passive-only model (TVG-P), and the active and passive combined model (TVG-AP). The accuracy of the calibrated models is evaluated by comparing the SMAP observations and the model simulations. The results show that TVG-AP can well reproduce the backscattering coefficient and brightness temperature, with correlation coefficients of 0.87, 0.89, 0.78, and 0.43 and root-mean-square errors of 0.49 dB, 0.52 dB, 7.20 K, and 10.47 K for σ HH⁰ , σ VV⁰ , TBH, and TBV, respectively. In contrast, TVG-A and TVG-P can only accurately model the backscattering coefficient and brightness temperature, respectively. Without any modifications of the calibrated parameters, the error metrics computed from the validation data are slightly worse than those of the calibration data. These results demonstrate the feasibility of the synergistic use of SMAP active radar and passive radiometer observations under the unified framework of a physical model. In addition, the results demonstrate the necessity and effectiveness of applying GSA in model optimization. It is expected that these findings can contribute to the development of model-based soil moisture retrieval methods using active and passive microwave remote sensing data

    Chlorido[(E)-2-hydr­oxy-6-(isonicotinoyl­hydrazonometh­yl)phen­yl]mercury(II) monohydrate

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    The asymmetric unit of the title compound, [Hg(C13H10N3O2)Cl]·H2O, contains two independent mercury(II) complexes with slightly different conformations, related via a pseudo-inversion centre, and two water mol­ecules. The HgII atoms show a typical linear geometry to a C atom of the benzene ring and to a Cl atom. A benzene C and the azomethine N atom chelate the HgII atoms with weak intra­molecular Hg⋯N bonding distances of 2.735 (3) and 2.739 (3) Å, respectively. The resulting five-membered metallacycles are nearly coplanar with the benzene rings [dihedral angles = 0.9 (1) and 0.7 (1)°], while the pyridine rings make dihedral angles with the benzene units of 58.17 (1) and 56.58 (1)°. In the crystal structure, the HgII complexes are linked by hydr­oxy donor and pyridine acceptor groups into chains along [010]. The water mol­ecules connect the complexes through inter­molecular O—H⋯Ocarbon­yl bonds in the a-axis direction, and the azomethine H atoms donate towards the water O atoms, forming a three-dimensional network of inter­molecular O—H⋯N, O—H⋯O and N—H⋯O hydrogen bonds

    Synovial Macrophages: Past Life, Current Situation, and Application in Inflammatory Arthritis

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    Inflammatory arthritis is an inflammatory disease that involves the joints and surrounding tissues. Synovial hyperplasia often presents when joints become inflamed due to immune cell infiltration. Synovial membrane is an important as well as a highly specific component of the joint, and its lesions can lead to degeneration of the joint surface, causing pain and joint disability or affecting the patients’ quality of life in severe cases. Synovial macrophages (SMs) are one of the cellular components of the synovial membrane, which not only retain the function of macrophages to engulf foreign bodies in the joint cavity, but also interact with synovial fibroblasts (SFs), T cells, B cells, and other inflammatory cells to promote the production of a variety of pro-inflammatory cytokines and chemokines, such as TNF-α, IL-1β, IL-8, and IL-6, which are involved in the pathogenic process of inflammatory arthritis. SMs from different tissue sources have differently differentiated potentials and functional expressions. This article provides a summary on studies pertaining to SMs in inflammatory arthritis, and explores their role in its treatment, in order to highlight novel treatment modalities for the disease

    Magnetic Feshbach resonances in collisions of 23Na40K with 40K

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    We present measurements of more than 80 magnetic Feshbach resonances in collisions of ultracold 23Na40K with 40K. We assign quantum numbers to a group of low-field resonances and show that they are probably due to long-range states of the triatomic complex in which the quantum numbers of the separated atom and molecule are approximately preserved. The resonant states are not members of chaotic bath of short-range states. Similar resonances are expected to be a common feature of alkali-metal diatom + atom systems

    Arabidopsis Hormone Database: a comprehensive genetic and phenotypic information database for plant hormone research in Arabidopsis

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    Plant hormones are small organic molecules that influence almost every aspect of plant growth and development. Genetic and molecular studies have revealed a large number of genes that are involved in responses to numerous plant hormones, including auxin, gibberellin, cytokinin, abscisic acid, ethylene, jasmonic acid, salicylic acid, and brassinosteroid. Here, we develop an Arabidopsis hormone database, which aims to provide a systematic and comprehensive view of genes participating in plant hormonal regulation, as well as morphological phenotypes controlled by plant hormones. Based on data from mutant studies, transgenic analysis and gene ontology (GO) annotation, we have identified a total of 1026 genes in the Arabidopsis genome that participate in plant hormone functions. Meanwhile, a phenotype ontology is developed to precisely describe myriad hormone-regulated morphological processes with standardized vocabularies. A web interface (http://ahd.cbi.pku.edu.cn) would allow users to quickly get access to information about these hormone-related genes, including sequences, functional category, mutant information, phenotypic description, microarray data and linked publications. Several applications of this database in studying plant hormonal regulation and hormone cross-talk will be presented and discussed

    The CDEX-1 1 kg Point-Contact Germanium Detector for Low Mass Dark Matter Searches

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    The CDEX Collaboration has been established for direct detection of light dark matter particles, using ultra-low energy threshold p-type point-contact germanium detectors, in China JinPing underground Laboratory (CJPL). The first 1 kg point-contact germanium detector with a sub-keV energy threshold has been tested in a passive shielding system located in CJPL. The outputs from both the point-contact p+ electrode and the outside n+ electrode make it possible to scan the lower energy range of less than 1 keV and at the same time to detect the higher energy range up to 3 MeV. The outputs from both p+ and n+ electrode may also provide a more powerful method for signal discrimination for dark matter experiment. Some key parameters, including energy resolution, dead time, decay times of internal X-rays, and system stability, have been tested and measured. The results show that the 1 kg point-contact germanium detector, together with its shielding system and electronics, can run smoothly with good performances. This detector system will be deployed for dark matter search experiments.Comment: 6 pages, 8 figure
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