Recently, the utilization of hydrogen-bonded organic frameworks (HOFs) with high crystallinity and inherent well-defined H-bonding networks in the field of proton conduction has received increasing attention, but obtaining HOFs with excellent water stability and prominent proton conductivity (σ) remains challenging. Herein, by employing functionalized terephthalic acids, 2,5-dihydroxyterephthalic acid, 2-hydroxyterephthalic acid, 2-nitro terephthalic acid, and terephthalic acid, respectively, four highly water-stable ionic HOFs (iHOFs), [(CHO)(MeNH)]∙2HO (iHOF 1), [(CHO)(MeNH)] (iHOF 2), [(CHNO)(MeNH)] (iHOF 3) and [(CHO)(MeNH)] (iHOF 4) were efficiently prepared by a straightforward synthesis approach in DMF and HO solutions. The alternating-current (AC) impedance testing in humid conditions revealed that all four iHOFs were temperature- and humidity-dependent σ, with the greatest value reaching 10 S·cm.
View Article and Find Full Text PDFA highly convenient copper(I)-catalyzed oxidation-initiated cyclopropanation of indolyl ynamide for the rapid construction of indole-fused cyclopropane-lactams is described, which represents, to the best of our knowledge, the first non-noble-metal-catalyzed indolyl ynamide oxidation/dearomatization by the in situ generated α-oxo copper carbenes. Compared to hydrazone and diazo, the use of alkynes as carbene precursors allows cyclopropanation to occur under a safe and convenient pathway. Moreover, this transformation can lead to the divergent synthesis of pentacyclic spiroindolines involving the reversal of ynamide regioselectivity by engineering substrate structures.
View Article and Find Full Text PDFIn the field of sensing, finding high-performance amine molecular sensors has always been a challenging topic. Here, two highly stable 3D MOFs and with large specific surface areas and hierarchical pore structures were conveniently synthesized by solvothermal reaction of ZrCl/HfCl with a simple organic ligand, 2,5-thiophene dicarboxylic acid (HTDC) according to literature approach. By analyzing TGA data, it was found that the two MOFs have defects (unsaturated metal sites) that can interact with substrates (HO and volatile amine gas), which is conducive to proton transfer and amine compound identification.
View Article and Find Full Text PDFZhonghua Nan Ke Xue
February 2020
Objective: To investigate the expression of phosphoribosyl pyrophosphate synthase 2 (PRPS2) in the human testis and its clinical significance.
Methods: Using quantitative real-time PCR (qRT-PCR) and immunohistochemistry, we detected the expression of PRPS2 mRNA in the testis tissue of the men with normal spermatogenesis or mile, moderate or severe hypospermatogenesis (HS) and that of the PRPS2 protein in the testicular biopsy tissue of 67 adult males. Then, we analyzed the relationship of the PRPS2 expressions with the testicular histological types and clinical parameters of the subjects.
J Glob Antimicrob Resist
June 2020
Objectives: Minocycline is increasingly used clinically for treating infections due to multidrug resistant bacteria. We previously reported that the serum protein binding of minocycline atypically correlated with total concentration using microdialysis, but the therapeutic implications of this finding remained unclear. The objective of this study was to ascertain the functional impact of serum protein binding on bacterial killing.
View Article and Find Full Text PDFPhosphoribosyl-pyrophosphate synthetase 2 (PRPS2) is a rate-limiting enzyme and plays an important role in purine and pyrimidine nucleotide synthesis. Recent studies report that PRPS2 is involved in male infertility. However, the role of PRPS2 in hypospermatogenesis is unknown.
View Article and Find Full Text PDFObjectives: This study aimed to determine the effect of intraoperative administration of flurbiprofen on postoperative levels of programmed death 1 (PD-1) in patients undergoing thoracoscopic surgery.
Materials And Methods: In this prospective double-blind trial, patients were randomized to receive intralipid (control group, n = 34, 0.1 mL/kg, i.
Acquired resistance to chemotherapy is a major limitation for the successful treatment of lung cancer. Previously, we and others showed that formation of tumor spheres is associated with chemotherapy resistance in lung cancer cells, but the underlying mechanisms remained largely unknown. In the current study, we show that mitochondrial activity is significantly higher in A549 tumor spheres versus monolayer cells, establishing mitochondria as a putative target for antitumor therapy.
View Article and Find Full Text PDFYes-associated protein (YAP) serves a critical role in the initiation and progression of a variety of types of cancer via modulating the expression of genes involved in cell proliferation and the downregulation of apoptosis. Recent studies have suggested that YAP is responsible for the development of drug resistance and cancer metastasis and recurrence. However, the association between YAP and chemoresistance in lung cancer, particularly in lung cancer stem cells (LCSCs) remains largely unknown.
View Article and Find Full Text PDFA smart chemometrics-assisted strategy that combines the full scan mode of liquid chromatography with mass spectrometry with second-order calibration method based on alternating trilinear decomposition algorithm was developed for the rapid determination of 15 glucocorticoids including the epimers betamethasone and dexamethasone illegally added into face masks. Fifteen glucocorticoids were rapidly eluted (11 min) under a simple elution program. By means of the second-order calibration method, 15 target analytes were successfully quantified in the presence of peak overlaps, unknown interferences and baseline drifts.
View Article and Find Full Text PDFThis paper proposes a flexible and novel strategy that alternating trilinear decomposition (ATLD) method combines with two-dimensional linear discriminant analysis (2D-LDA). The developed strategy was applied to three-way chemical data for the characterization and classification of samples. In order to confirm the methodology performances of characterization and classification, a series of simulated three-way data arrays and a real-life EEMs data set involving the characterization and classification of tea samples according to the tea varieties were subjected to ATLD-2DLDA analysis.
View Article and Find Full Text PDFThe aim of the present work was to develop a rapid and interference-free method based on liquid chromatography-mass spectrometry (LC-MS) for the simultaneous determination of nine B-group vitamins in various energy drinks. A smart and green strategy that modeled the three-way data array of LC-MS with second-order calibration methods based on alternating trilinear decomposition (ATLD) and alternating penalty trilinear decomposition (APTLD) algorithms was developed. By virtue of "mathematical separation" and "second-order advantage", the proposed strategy successfully solved the co-eluted peaks and unknown interferents in LC-MS analysis with the elution time less than 4.
View Article and Find Full Text PDFIn this work, a smart chemometrics-enhanced strategy, high-performance liquid chromatography, and diode array detection coupled with second-order calibration method based on alternating trilinear decomposition algorithm was proposed to simultaneously quantify 12 polyphenols in different kinds of apple peel and pulp samples. The proposed strategy proved to be a powerful tool to solve the problems of coelution, unknown interferences, and chromatographic shifts in the process of high-performance liquid chromatography analysis, making it possible for the determination of 12 polyphenols in complex apple matrices within 10 min under simple conditions of elution. The average recoveries with standard deviations, and figures of merit including sensitivity, selectivity, limit of detection, and limit of quantitation were calculated to validate the accuracy of the proposed method.
View Article and Find Full Text PDFObjective: To establish a scientific method for identitication and evaluation of the Tibetan prescription Jia Ga Song Tang.
Methods: Volatile oil was extracted by water steam distillation and analyzed by GC-MS. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) were applied to the samples for chemical fingerprint pattern recognition research.
The presence of cancer stem cells (CSCs) is the source of occurrence, aggravation, and recurrence of lung cancer. Accordingly, targeting killing the lung CSCs has been suggested to be an effective approach for lung cancer treatment. In this study, we showed that rapamycin inhibited the mammalian target of rapamycin (mTOR) signal transduction in A549 cells and improved the sensitivity to cisplatin (DDP).
View Article and Find Full Text PDFJ Chromatogr B Analyt Technol Biomed Life Sci
July 2016
A novel chemometrics-assisted high performance liquid chromatography method coupled with diode array detector (HPLC-DAD) was proposed for the simultaneous determination of vincristine (VCR), vinblastine (VLB), vindoline (VDL), catharanthine (CAT) and yohimbine (YHB) in Catharanthus roseus (C. roseus) and human serum samples. With the second-order advantage of the alternating trilinear decomposition (ATLD) method, the resolution and rapid determination of five components of interest in complex matrices were performed, even in the present of heavy overlaps and unknown interferences.
View Article and Find Full Text PDFThe application of calibration transfer methods has been successful in combination with near-infrared spectroscopy or other tools for prediction of chemical composition. One of the developed methods that can provide accurate performances is the piecewise direct standardization (PDS) method, which in this paper is firstly applied to transfer from one day to another the second-order calibration model based on alternating trilinear decomposition (ATLD) method built for the interference-free resolution and determination of multi-analytes in complex systems by liquid chromatography-mass spectrometry (LC-MS) in full scan mode. This is an example of LC-MS analysis in which interferences have been found, making necessary the use of second-order calibration because of its capacity for modeling this phenomenon, which implies analytes of interest can be resolved and quantified even in the presence of overlapped peaks and unknown interferences.
View Article and Find Full Text PDFA simple method has been developed by combining high-performance liquid chromatography with diode array detection with the alternating trilinear decomposition method for simultaneous determination of four tyrosine kinase inhibitors in different human plasma samples. Chromatographic separation of the analytes was performed on a reversed-phase column with methanol (65%, v/v, A) and 0.1% aqueous solution of formic acid (35%, v/v, B).
View Article and Find Full Text PDFIncreasing evidence has shown that abnormal metabolic phenotypes in body fluids reflect the pathogenesis and pathophysiology of Parkinson's disease (PD). These body fluids include urine; however, the relationship between, specifically, urinary metabolic phenotypes and PD is not fully understood. In this study, urinary metabolites from a total of 401 clinical urine samples collected from 106 idiopathic PD patients and 104 normal control subjects were profiled by using high-performance liquid chromatography coupled to high-resolution mass spectrometry.
View Article and Find Full Text PDFA novel intrinsic fluorescence method for the direct determination of l-phenylalanine, l-tyrosine, and l-tryptophan in human plasma is presented. By using fluorescence excitation-emission-pH-sample data array in combination with four-way calibration method based on the quadrilinear component model, the proposed approach successfully achieved quantitative analysis of the aromatic amino acids in human plasma, even in the presence of an unknown, uncalibrated serious interferent. It needs little preparation, uses the "mathematical separation" instead of "analytical separation", what makes it fast and environmentally friendly.
View Article and Find Full Text PDFAsian Pac J Allergy Immunol
September 2012
Background: Few data on the effect of antihistamines on patch test results in Chinese patients are currently available.
Objectives: To evaluate the effect of desloratadine on patch test reactions.
Methods: Patients known to have at least one strongly positive (+ +) test with an allergen were re-patch tested after 14 to 70 days (average time interval 26.
Abnormal protein aggregation in the brain is linked to the pathogenesis of neurodegenerative diseases, including Alzheimer's disease (AD) and Parkinson's disease (PD). Recent studies revealed that the oligomeric form of aggregates is most likely the toxic species, and thus could be a good therapeutic target. To screen for potent inhibitors that can inhibit both oligomerisation and fibrillation of α-synuclein (α-syn), we systematically compared the antioligomeric and antifibrillar activities of eight compounds that were extracted from Chinese herbal medicines through three platforms that can monitor the formation of α-syn fibrils and oligomers in cell-free or cellular systems.
View Article and Find Full Text PDFThe study was conducted to investigate the effect of Salvianolic acid B (Sal B) on TNF-alpha-stimulated adhesion molecule expression i.e. vascular adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1) and E-selectin in human aortic endothelial cells (HAECs) under laminar shear stress (LSS) condition.
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