2,132 research outputs found

    One new cucurbitane triterpenoid from the fruits of Momordica charantia

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    One new cucurbitane triterpenoid commonly named neokuguaglucoside, together with three known compounds momordicoside M, momordicoside N, and momordicoside A were isolated from the fresh fruits of Momordica charantia. The new one's structure with an interesting sugar-like groups attached to the side chain was elucidated by spectroscopic analysis and semiepirical (AM1) quantum chemical method

    Amide Activation by Tf2O: Reduction of Amides to Amines by NaBH4 under Mild Conditions

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    An expeditious and practical method for the reduction of amides to amines is reported. The method is consisted of activation of amides with Tf2O followed by reduction with sodium borohydride in THF at room temperature. Various amides/lactams gave the corresponding amines in good to excellent yields, even with hindered amides and secondary amides. This method also presents other advantages such as TBDPS-group tolerance, short reaction time, simple workup and purification procedure.NSF of China [20832005]; National Basic Research Program (973 Program) of China [2010CB833200

    Relations between near-field enhancements and Purcell factors in hybrid nanostructures of plasmonic antennas and dielectric cavities

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    Strong near-field enhancements (NFEs) of nanophotonic structures are believed to be closely related to high Purcell factors (FP). Here, we theoretically show that the correlation is partially correct; the extinction cross section ({\sigma}) response is also critical in determining FP. The divergence between NFE and FP is especially pronounced in plasmonic-dielectric hybrid systems, where the plasmonic antenna supports dipolar plasmon modes and the dielectric cavity hosts Mie-like resonances. The cavity's enhanced-field environment can boost the antenna's NFEs, but the FP is not increased concurrently due to the larger effective {\sigma} that is intrinsic to the FP calculations. Interestingly, the peak FP for the coupled system can be predicted by using the NFE and {\sigma} responses. Furthermore, the limits for FP of coupled systems are considered; they are determined by the sum of the FP of a redshifted (or modified, if applicable) antenna and an individual cavity. This contrasts starkly with the behavior of NFE which is closely associated with the multiplicative effects of the NFEs provided by the antenna and the dielectric cavity. The differing behaviors of NFE and FP in hybrid cavities have varied impacts on relevant nanophotonic applications such as fluorescence, Raman scattering and enhanced light-matter interactions

    Up-regulation of hexokinase1 in the right ventricle of monocrotaline induced pulmonary hypertension

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    BACKGROUND: Pulmonary arterial hypertension (PAH) is a proliferative arteriopathy associated with a glycolytic shift during heart metabolism. An increase in glycolytic metabolism can be detected in the right ventricle during PAH. Expression levels of glycolysis genes in the right ventricle during glycolysis that occur in monocrotaline (MCT)-induced pulmonary hypertension (PH) remain unknown. METHODS: PH was induced by a single subcutaneous injection of MCT (50 mg/kg) into rats, eventually causing right heart failure. Concurrently, a control group was injected with normal saline. The MCT-PH rats were randomly divided into three groups according to MCT treatment: MCT-2 week, 3 week, and 4 week groups (MCT-2w, 3w, 4w). At the end of the study, hemodynamics and right ventricular hypertrophy were compared among experimental groups. Expression of key glycolytic candidate genes was screened in the right ventricle. RESULTS: We observed an increase in mean pulmonary arterial pressure, right ventricular systolic pressure and right ventricular hypertrophy index three weeks following MCT injection. Alterations in the morphology and structure of right ventricular myocardial cells, as well as the pulmonary vasculature were observed. Expression of hexokinase 1 (HK1) mRNA began to increase in the right ventricle of the MCT-3w group and MCT-4w group, while the expression of lactate dehydrogenase A (LDHA) was elevated in the right ventricle of the MCT-4w group. Hexokinase 2(HK2), pyruvate dehydrogenase complex α1 (PDHα1), and LDHA mRNA expression showed no changes in the right ventricle. HK1 mRNA expression was further confirmed by HK1 protein expression and immunohistochemical analyses. All findings underlie the glycolytic phenotype in the right ventricle. CONCLUSIONS: There was an increase in the protein and mRNA expression of hexokinase-1 (HK1) three and four weeks after the injection of monocrotaline in the right ventricle, intervention of HK1 may be amenable to therapeutic intervention

    Tetra­aqua­(2,2′-bipyridine-κ2 N,N′)magnesium(II) bis­(4-fluoro­benzoate)

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    The title compound, [Mg(C10H8N2)(H2O)4](C7H4FO2)2, consists of a bivalent [Mg(C10H8N2)(H2O)4]2+ cation and two 4-fluorbenzoate anions. In the complex cation, the MgII atom is coordinated by two N atoms from a 2,2′-bipyridine ligand and four water O atoms in a distorted MgN2O4 octa­hedral geometry. The MgII atom is located on a twofold rotation axis and thus a cation exhibits C 2 mol­ecular symmetry. The 2,2′-bipyridine ligands exhibit nearly perfect planarity (r.m.s. deviations = 0.0061 Å). In the crystal, O—H⋯O and C—H⋯O hydrogen bonds link the cations and anions into a three-dimensional supra­molecular network

    Capillary Hemangioma of the Middle Ear and External Auditory Canal: a Case Report

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    AbstractWe report a case of capillary hemangiomsa that involved the entire middle ear space, external auditory canal(EAC) and tympanic antrum. Symptoms in the case included ear fullness, hearing loss, otalgia and otorrhea. The case was misdiagnosed as recurrent chronic otitis media with granulation preoperatively. A diagnosis of capillary hemangioma was established by postoperative histological examination. The management of capillary hemangioma of the middle ear and external auditory canal is discussed, with a review of the literature. Because of its variable and sometimes misleading clinical presentation, hemangioma can initially be misdiagnosed as other lesions. Therefore, a high index of suspicion is necessary for early and accurate diagnosis

    Identify submitochondria and subchloroplast locations with pseudo amino acid composition: Approach from the strategy of discrete wavelet transform feature extraction

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    AbstractIt is very challenging and complicated to predict protein locations at the sub-subcellular level. The key to enhancing the prediction quality for protein sub-subcellular locations is to grasp the core features of a protein that can discriminate among proteins with different subcompartment locations. In this study, a different formulation of pseudoamino acid composition by the approach of discrete wavelet transform feature extraction was developed to predict submitochondria and subchloroplast locations. As a result of jackknife cross-validation, with our method, it can efficiently distinguish mitochondrial proteins from chloroplast proteins with total accuracy of 98.8% and obtained a promising total accuracy of 93.38% for predicting submitochondria locations. Especially the predictive accuracy for mitochondrial outer membrane and chloroplast thylakoid lumen were 82.93% and 82.22%, respectively, showing an improvement of 4.88% and 27.22% when other existing methods were compared. The results indicated that the proposed method might be employed as a useful assistant technique for identifying sub-subcellular locations. We have implemented our algorithm as an online service called SubIdent (http://bioinfo.ncu.edu.cn/services.aspx)
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