3,786 research outputs found
{Bis[4-(2-pyridyl)pyrimidin-2-yl] sulfide}dibromidocobalt(II)
The title compound, [CoBr2(C18H12N6S)], is a mononuclear complex in which a twofold rotation axis passes through the Co and S atoms. The CoII center is six-coordinated by four N atoms from one bis[4-(2-pyridyl)pyrimidin-2-yl] sulfide (L) ligand and two bromide anions, forming an octahedral coordination geometry, where the four donor N atoms are located in the equatorial plane and the Br atoms occupy the axial positions. The sum of the bond angles around the Co atom in the equatorial plane is 360.5°, with the four N atoms and the central Co atom almost coplanar. In the crystal structure, the mononuclear units are linked by π–π stacking interactions (the interplanar distances are 3.469 and 3.533 Å, and the corresponding centroid–centroid distances are 3.791 and 3.896 Å) into a three-dimensional supramolecular network
4,4′-Bis(benzimidazol-1-yl)biphenyl
The molecule of the title compound, C26H18N4, resides on a crystallographic inversion centre with a dihedral angle of 44.94 (5)° between the benzimidazole ring system and the benzene ring. The primary hydrogen bond is C—H⋯N and inversion-related pairs of these generate a chain of rings along the c-axis direction; π⋯π stacking involving the benzimidazole groups with interplanar separations of ca 3.4 Å complete the interactions
Bis[μ-1,1′-methylenebis(1H-imidazole)-κ2 N 3:N 3′]bis[dichloridocobalt(II)]
The title compound, [Co2Cl4(C7H8N4)2], contains a dinuclear complex molecule in which each CoII atom is tetrahedrally coordinated by two N atoms and two chloride ions. The 1,1′-methylenebis(1H-imidazole) ligands adopt a bis-monodentate bridging mode linking two CoII atoms
Laser ablation resistance and mechanism of Si-Zr alloyed melt infiltrated C/C-SiC composite
Ablation resistance of C/C-SiC composite prepared via Si-Zr alloyed reactive melt infiltration was evaluated using a facile and economical laser ablation method. Linear ablation rates of the composite increased with an increase in laser power densities and decreased with extended ablation time. The C/C-SiC composite prepared via Si-Zr alloyed melt infiltration presented much better ablation resistance compared with the C/SiC composite prepared by polymer infiltration and pyrolysis process. The good ablation resistance of the composite was attributed to the melted ZrC layer formed at the ablation center region. Microstructure and phase composition of different ablated region were investigated by SEM and EDS, and a laser ablation model was finally proposed based on the testing results and microstructure characterization. Laser ablation of the composite experienced three distinct periods. At the very beginning, the laser ablation was dominated by the oxidation process. Then for the second period, the laser ablation was dominated by the evaporation, decomposition and sublimation process. With the further ablation of the composite, chemical stable ZrC was formed on the ablated surface and the laser ablation was synergistically controlled by the scouring away of ZrC melts and evaporation, decomposition and sublimation process.This work is supported by National Natural Science Foundation of China (51641502)
catena-Poly[[[diiodidocadmium(II)]-μ-1-(4-pyridylmethyl)-1H-benzimidazole] methanol hemisolvate]
In the title coordination polymer, {[CdI2(C13H11N3)]·0.5CH4O}n, each CdII center is four-coordinated by two N-atom donors from two 1-(4-pyridylmethyl)-1H-benzimidazole (L) ligands and two iodide anions, forming a tetrahedral coordination geometry. L ligands bridge adjacent CdII ions, generating two crystallographically independent approximately orthogonal one-dimensional chains. The methanol solvent molecule associates with one of the chains via O—H⋯I interactions
SnoRNAs from the filamentous fungus Neurospora crassa: structural, functional and evolutionary insights
<p>Abstract</p> <p>Background</p> <p>SnoRNAs represent an excellent model for studying the structural and functional evolution of small non-coding RNAs involved in the post-transcriptional modification machinery for rRNAs and snRNAs in eukaryotic cells. Identification of snoRNAs from <it>Neurospora crassa</it>, an important model organism playing key roles in the development of modern genetics, biochemistry and molecular biology will provide insights into the evolution of snoRNA genes in the fungus kingdom.</p> <p>Results</p> <p>Fifty five box C/D snoRNAs were identified and predicted to guide 71 2'-O-methylated sites including four sites on snRNAs and three sites on tRNAs. Additionally, twenty box H/ACA snoRNAs, which potentially guide 17 pseudouridylations on rRNAs, were also identified. Although not exhaustive, the study provides the first comprehensive list of two major families of snoRNAs from the filamentous fungus <it>N. crassa</it>. The independently transcribed strategy dominates in the expression of box H/ACA snoRNA genes, whereas most of the box C/D snoRNA genes are intron-encoded. This shows that different genomic organizations and expression modes have been adopted by the two major classes of snoRNA genes in <it>N. crassa </it>. Remarkably, five gene clusters represent an outstanding organization of box C/D snoRNA genes, which are well conserved among yeasts and multicellular fungi, implying their functional importance for the fungus cells. Interestingly, alternative splicing events were found in the expression of two polycistronic snoRNA gene hosts that resemble the UHG-like genes in mammals. Phylogenetic analysis further revealed that the extensive separation and recombination of two functional elements of snoRNA genes has occurred during fungus evolution.</p> <p>Conclusion</p> <p>This is the first genome-wide analysis of the filamentous fungus <it>N. crassa </it>snoRNAs that aids in understanding the differences between unicellular fungi and multicellular fungi. As compared with two yeasts, a more complex pattern of methylation guided by box C/D snoRNAs in multicellular fungus than in unicellular yeasts was revealed, indicating the high diversity of post-transcriptional modification guided by snoRNAs in the fungus kingdom.</p
Tetrakis(2,2′-bipyridine)di-μ3-hydroxido-bis(μ-2-oxidobenzoato)tetracopper(II) dinitrate tetrahydrate
The tetranuclear title complex, [Cu4(C7H4O3)2(OH)2(C10H8N2)4](NO3)2·4H2O, has a crystallographically imposed centre of symmetry. The CuII atoms display a distorted square-pyramidal coordination geometry and are linked by two μ2-phenolate O atoms from the salicylate ligands and two μ3-hydroxo groups, forming a Cu4O4 core that adopts a ‘stepped-cubane’ geometry. In the crystal, the cations are linked by O—H⋯O hydrogen bonds to the nitrate anions, which are in turn connected via O—H⋯O interactions to centrosymmentric water tetramers
An expert consensus for the management of chronic hepatitis B in Asian Americans.
BACKGROUND: Hepatitis B virus (HBV) infection is common with major clinical consequences. In Asian Americans, the HBsAg carrier rate ranges from 2% to 16% which approximates the rates from their countries of origin. Similarly, HBV is the most important cause of cirrhosis, hepatocellular carcinoma (HCC) and liver related deaths in HBsAg positive Asians worldwide.
AIM: To generate recommendations for the management of Asian Americans infected with HBV.
METHODS: These guidelines are based on relevant data derived from medical reports on HBV from Asian countries as well as from studies in the HBsAg positive Asian Americans. The guidelines herein differ from other recommendations in the treatment of both HBeAg positive and negative chronic hepatitis B (CHB), in the approach to HCC surveillance, and in the management of HBV in pregnant women.
RESULTS: Asian American patients, HBeAg positive or negative, with HBV DNA levels \u3e2000 IU/mL (\u3e10
CONCLUSIONS: Application of the recommendations made based on a review of the relevant literature and the opinion of a panel of Asian American physicians with expertise in HBV treatment will inform physicians and improve patient outcomes
Pulmonary Nodule Classification Based on Heterogeneous Features Learning
IEEE Pulmonary cancer is one of the most dangerous cancers with a high incidence and mortality. An early accurate diagnosis and treatment of pulmonary cancer can observably increase the survival rates, where computer-aided diagnosis systems can largely improve the efficiency of radiologists. In this paper, we propose a deep automated lung nodule diagnosis system based on three-dimensional convolutional neural network (3D-CNN) and support vector machine (SVM) with multiple kernel learning (MKL) algorithms. The system not only explores the computed tomography (CT) scans, but also the clinical information of patients like age, smoking history and cancer history. To extract deeper image features, a 34-layers 3D Residual Network (3D-ResNet) is employed. Heterogeneous features including the extracted image features and the clinical data are learned with MKL. The experimental results prove the effectiveness of the proposed image feature extractor and the combination of heterogeneous features in the task of lung nodule diagnosis
Repeat dose exposure of PM2.5 triggers the Disseminated Intravascular Coagulation (DIC) in SD Rats
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