444 research outputs found

    3-(4-Amino-5-thioxo-4,5-dihydro-1H-1,2,4-triazol-3-yl)pyridinium chloride

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    In the title compound, C7H8N5S+·Cl−, the dihedral angle formed by the pyridine ring with the triazole ring is 10.0 (1)°. There are weak inter­molecular hydrogen-bond inter­actions in the crystal structure, involving the NH and NH2 groups as donors, and the chloride anion, the S atom in the thio­ketone group and the unsubstituted ring N atom as acceptors

    A chalcone derivative reactivates latent HIV-1 transcription through activating P-TEFb and promoting Tat-SEC interaction on viral promoter.

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    The principal barrier to the eradication of HIV/AIDS is the existence of latent viral reservoirs. One strategy to overcome this barrier is to use latency-reversing agents (LRAs) to reactivate the latent proviruses, which can then be eliminated by effective anti-retroviral therapy. Although a number of LRAs have been found to reactivate latent HIV, they have not been used clinically due to high toxicity and poor efficacy. In this study, we report the identification of a chalcone analogue called Amt-87 that can significantly reactivate the transcription of latent HIV provirses and act synergistically with known LRAs such as prostratin and JQ1 to reverse latency. Amt-87 works by activating the human transcriptional elongation factor P-TEFb, a CDK9-cyclin T1 heterodimer that is part of the super elongation complex (SEC) used by the viral encoded Tat protein to activate HIV transcription. Amt-87 does so by promoting the phosphorylation of CDK9 at the T-loop, liberating P-TEFb from the inactive 7SK snRNP, and inducing the formation of the Tat-SEC complex at the viral promoter. Together, our data reveal chalcones as a promising category of compounds that should be further explored to identify effective LRAs for targeted reversal of HIV latency

    Characteristics of Traffic Flow at Nonsignalized T-Shaped Intersection with U-Turn Movements

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    Most nonsignalized T-shaped intersections permit U-turn movements, which make the traffic conditions of intersection complex. In this paper, a new cellular automaton (CA) model is proposed to characterize the traffic flow at the intersection of this type. In present CA model, new rules are designed to avoid the conflicts among different directional vehicles and eliminate the gridlock. Two kinds of performance measures (i.e., flux and average control delay) for intersection are compared. The impacts of U-turn movements are analyzed under different initial conditions. Simulation results demonstrate that (i) the average control delay is more practical than flux in measuring the performance of intersection, (ii) U-turn movements increase the range and degree of high congestion, and (iii) U-turn movements on the different direction of main road have asymmetrical influences on the traffic conditions of intersection

    Preparation and properties of a washable flame-retardant coated fabric

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    In this study, a flame-retardant-coating (FRC) agent has been prepared using hydrophobic organic silicone-phosphorus-nitrogen flame retardant and acrylic emulsion. Polyester-cotton blend fabric (P/C) has been treated with FRC agent, and the finishing process, thermal decomposition, flame retardancy, washability, softness and other properties are studied. Results show that the treated fabrics are of good flame retardancy; LOI is up to 32%, thermal degradation rate reduces by 7.8 %/min and thermal damage reduces by 74%. Limiting oxygen index (LOI) is found to be 24.6% and 23.7% for 5 and 10 times washing. The fastness shows excellent washability

    Effects of Grain Orientation on Stress State near Grain Boundary of Austenitic Stainless Steel Bicrystals

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    The stress state at the crack tip of structural components in nuclear power plants used in the SCC quantitative prediction models is based on the assumption that the polycrystalline material is isotropic and homogeneous at present. However, the crystals in polycrystalline materials are anisotropic with different orientations, which would induce a nonuniform stress to cause the initiation and propagation of SCC. By using a finite element method, the elastic responses of anisotropic behaviors of austenitic stainless steel bicrystals are studied. The results indicate that the stress distribution near GBs depends strongly on the crystal orientation. A larger Mises stress concentration exists on the GB with larger stiffness along the load direction. The Mises stress difference is higher in the bicrystal with bigger elastic modulus difference of two neighboring grains along the tensile axis. In the bicrystal with GB perpendicular to the tensile axis, the grain orientation has little effects on the Mises stress far from the GB in both grains. The strain inconsistency in bicrystals is affected by the mismatch of two neighboring grains. The larger the elastic modulus differences between two neighboring grains caused by misorientation, the larger the strain inconsistency in the bicrystal

    Study on the Size-Dependent Oxidation Reaction Kinetics of Nanosized Zinc Sulfide

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    Numerous oxidation problems of nanoparticles are often involved during the preparation and application of nanomaterials. The oxidation rate of nanomaterials is much faster than bulk materials due to nanoeffect. Nanosized zinc sulfide (nano-ZnS) and oxygen were chosen as a reaction system. The influence regularities were discussed and the influence essence was elucidated theoretically. The results indicate that the particle size can remarkably influence the oxidation reaction kinetics. The rate constant and the reaction order increase, while the apparent activation energy and the preexponential factor decrease with the decreasing particle size. Furthermore, the logarithm of rate constant, the apparent activation energy and the logarithm of preexponential factor are linearly related to the reciprocal of particle diameter, respectively. The essence is that the rate constant is influenced by the combined effect of molar surface energy and molar surface entropy, the reaction order by the molar surface area, the apparent activation energy, by the molar surface energy, and the preexponential factor by the molar surface entropy. The influence regularities and essence can provide theoretical guidance to solve the oxidation problems involved in the process of preparation and application of nanomaterials

    Congenital Malaria in China

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    Background:Congenital malaria, in which infants are directly infected with malaria parasites from their mother prior to or during birth, is a potentially life-threatening condition that occurs at relatively low rates in malaria-endemic regions. It is recognized as a serious problem in Plasmodium falciparum-endemic sub-Saharan Africa, where recent data suggests that it is more common than previously believed. In such regions where malaria transmission is high, neonates may be protected from disease caused by congenital malaria through the transfer of maternal antibodies against the parasite. However, in low P. vivax-endemic regions, immunity to vivax malaria is low; thus, there is the likelihood that congenital vivax malaria poses a more significant threat to newborn health. Malaria had previously been a major parasitic disease in China, and congenital malaria case reports in Chinese offer valuable information for understanding the risks posed by congenital malaria to neonatal health. As most of the literature documenting congenital malaria cases in China are written in Chinese and therefore are not easily accessible to the global malaria research community, we have undertaken an extensive review of the Chinese literature on this subject.Methods/Principal Findings:Here, we reviewed congenital malaria cases from three major searchable Chinese journal databases, concentrating on data from 1915 through 2011. Following extensive screening, a total of 104 cases of congenital malaria were identified. These cases were distributed mainly in the eastern, central, and southern regions of China, as well as in the low-lying region of southwest China. The dominant species was P. vivax (92.50%), reflecting the malaria parasite species distribution in China. The leading clinical presentation was fever, and other clinical presentations were anaemia, jaundice, paleness, diarrhoea, vomiting, and general weakness. With the exception of two cases, all patients were cured with antimalarial drugs such as chloroquine, quinine, artemether, and artesunate.Conclusions:The symptoms of congenital malaria vary significantly between cases, so clear and early diagnosis is difficult. We suggest that active surveillance might be necessary for neonates born to mothers with a history of malaria

    Synthesis and Anticancer Activity Evaluation of Novel Phenanthridine Derivatives

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    Based on the structure of sanguinarine, fourteen phenanthridine derivatives were designed and synthesized in the current study. The cytotoxic activities of synthesized compounds were evaluated against five human cancer cell lines (MCF-7, PC3, Hela, A549, and HepG2 cell lines) via MTT assay. Among all the compounds tested, molecule 8a exhibited significant cytotoxic activity against MCF-7 cells with a IC50 value of 0.28 μM. A following up enzymatic assay indicated that compound 8a could inhibit the activity of DNA topoisomerase I/II. Further mechanistic studies performed in the MCF-7 cell line revealed that compound 8a could arrest cell cycle in S phase and induce cell apoptosis via downregulation of Bcl-2 and upregulation of Bax. Collectively, a potent DNA topoisomerase inhibitor (8a) was discovered, which exhibited potential as a candidate chemotherapeutic agent for the management of tumors in the present study

    Spinal posture assessment and low back pain

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    Postural assessment can help doctors and therapists identify risk factors for low back pain and determine appropriate follow-up treatment. Postural alignment is not perfectly symmetrical, and small asymmetries can instead represent norms and criteria for postural evaluation. It is necessary to comprehensively observe patients’ posture in all directions and analyze the factors related to posture evaluation. The results of reliability show that in general intra-rater reliability is higher than inter-rater reliability, and inclinometers are being more reliable than other instrumentations. Some common postural problems can cause lumbar discomfort, and prolonged poor posture is a potential risk factor for lumbar spine injuries. On the basis of previous studies on posture evaluation, a unified standardized method for posture evaluation must be established in future research

    A new polymorph of magnesium oxalate dihydrate

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    In the asymmetric unit of the title compound, catena-poly[[diaqua­magnesium(II)]-μ-oxalato], [Mg(C2O4)(H2O)2]n, there is one Mg atom in an octa­hedral coordination with site symmetry 222, a unique C atom of the oxalate anion lying on a twofold axis, an O atom of the anion in a general position and a water O atom at a site with imposed twofold rotation symmetry. The Mg2+ ions are ligated by water mol­ecules and bridged by the anions to form chains that are held together by O—H⋯O hydrogen bonds. The structure of the title compound has already been reported in a different space group [Lagier, Pezerat & Dubernat (1969 ▶). Rev. Chim. Miner. 6, 1081–1093; Levy, Perrotey & Visser (1971 ▶). Bull. Soc. Chim. Fr. pp. 757–761]
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