Microstructure and mechanical properties of spark plasma sintered Ti–Mo alloys for dental applications

Ti-Mo alloys with various Mo contents from 6wt% to 14wt% were processed by spark plasma sintering based on elemental pow- ders. The influence of sintering temperature and Mo content on the microstructure and mechanical properties of the resulting alloys were investigated. For each Mo concentration, the optimum sintering temperature was determined, resulting in a fully dense and uniform microstructure of the alloy. The optimized sintering temperature gradually increases in the range of 1100-1300℃ with the increase in Mo content. The microstructure of the Ti-（6-12）Mo ahoy consists of acicular α phase surrounded by equiaxed grains of 13 phase, while the Ti-14Mo al- loy only contains single 13 phase. A small amount of fine α lath precipitated from 13 phase contributes to the improvement in strength and hardness of the alloys. Under the sintering condition at 1250℃, the Ti-12Mo alloy is found to possess superior mechanical properties with the Vickers hardness of Hv 472, the compressive yield strength of 2182 MPa, the compression rate of 32.7%, and the elastic modulus of 72.1 GPa. These results demonstrate that Ti-Mo alloys fabricated via spark plasma sintering are indeed a perspective candidate alloy for dental applications.

Coherence migration in high-dimensional bipartite systems

The conservation law for first-order coherence and mutual correlation of a bipartite qubit state was firstly proposed by Svozil′?k et al.,and their theories laid the foundation for the study of coherence migration under unitary transformations.In this paper,we generalize the framework of first-order coherence and mutual correlation to an arbitrary(m■n)-dimensional bipartite composite state by introducing an extended Bloch decomposition form of the state.We also generalize two kinds of unitary operators in high-dimensional systems,which can bring about coherence migration and help to obtain the maximum or minimum first-order coherence.Meanwhile,the coherence migration in open quantum systems is investigated.We take depolarizing channels as examples and establish that the reduced first-order coherence of the principal system over time is completely transformed into mutual correlation of the(2■4)-dimensional system-environment bipartite composite state.It is expected that our results may provide a valuable idea or method for controlling the quantum resource such as coherence and quantum correlations.

量子自旋霍尔绝缘体Bi_(4)Br_(4)体与边缘的可区分的光学性质研究

量子自旋霍尔绝缘体拥有具有带隙的体态和无能隙的一维拓扑边缘态.然而,由于拓扑边缘态局域在纳米尺度,所以很难用光学手段直接观测并区分体态和边缘态,这就限制了对拓扑边缘态独特的光学特性和光电响应等方面的研究和应用.Bi_(4)Br_(4)体材料的台阶存在一维非平庸的边缘态,多个台阶累加的效应使得通过较为宏观的光学和光电分析手段来研究一维边缘态成为可能.该工作利用中远红外显微吸收光谱和泵浦探测光谱,对比研究了Bi_(4)Br_(4)体和边缘的光学响应行为.研究发现Bi_(4)Br_(4)的边缘在小于带隙(约0.22 eV)的波段存在明显的强于体内的红外吸收,且该吸收呈现较强的各向异性.室温下的红外泵浦探测首次观察到边缘处载流子激发态超长的弛豫时间(1.5 ns),该激发态载流子寿命要比体内载流子寿命长两个量级.该工作证实体态和拓扑边缘态具有明显不同的光学和光电响应行为,为未来设计新型红外探测器提供了材料和物理基础.

Leaflet Movement of Robinia pseudoacacia in Response to a Changing Light Environment

Diurnal and nocturnal leaflet movement of black locust （Robinia pseudoacacia L.） was investigated under three light schemes： 100% natural irradiance, 50% shading, and 90% shading. Changes in leaf mid-vein angle were described by measurements of two planes： （i） β, the angle formed by the bottom of the petiolule and its relation to the horizontal plane; and （ii） θ, the angle between the petiolule and the main leaflet vein. The two highest light regimens had a significant effect on β. Variation in β tends to make the leaflet more erect, thereby minimizing any negative impact of high irradiance on leaf lamina. Light-dark rhythms induced variation in θ （termed nyctinastic movement）. Nyctinastic movement is important during the low light levels experienced by leaflets in early morning and late afternoon. At low light levels, the leaflet stopped nyctinastic movement and θ was fixed at an angle that may have enabled the leaf lamina to maximize light interception. After the light-dark cycle was reestablished, nyctinastic movement was restored. Taken together, our results suggest that irradiance induces variation in β leading to diurnal leaflet movement （diaheliotropism）, whereas the light-dark cycle influences θ, which results in nocturnal leaflet movement. Both angles are important for describing patterns of leaf movement in R. pseudocacia.

Relative Bioavailability of Rifampicin in Four Chinese Fixed-dose Combinations Compared with Rifampicin in Free Combinations

Background：Decreases in the bioavailability of rifampicin （RFP） can lead to the development of drug resistance and treatment failure.Therefore,we investigated the relative bioavailability of RFP from one four-drug fixed-dose combination （FDC; formulation A） and three two-drug FDCs （formulations B,C,and D） used in China,compared with RFP in free combinations of these drugs （reference）,in healthy volunteers.Methods：Eighteen and twenty healthy Chinese male volunteers participated in two open-label,randomized two-period crossover （formulations A and C） or one three-period crossover （formulations B and D） study,respectively.The washout period between treatments was 7 days.Bioequivalence was assessed based on 90％ confidence intervals,according to two one-sided t-tests.All analyses were done with DAS 3.1.5 （Mathematical Pharmacology Professional Committee of China,Shanghai,China）.Results：Mean pharmacokinetic parameter values of RFP obtained for formulations A,B,C,and D products were 11.42 ± 3.41 μg/ml,7.86 ± 5.78 μg/ml,13.05 ± 6.80 μg/ml,and 16.18 ± 3.87 μg/ml,respectively,for peak plasma concentration （Cmax）,91.43± 30.82 μg·h-1 ·ml-1,55.49 ± 37.58 μg·h-1·ml-1,96.50 ± 47.24 μg·h-1·ml-1,101.47 ± 33.07 μg·h-1·ml-1,respectively,for area under the concentration-time curve （AUC0-2,4 h）.Conclusions：Although the concentrations of RFP for formulations A,C,and D were within the reported acceptable therapeutic range,only formulation A was bioequivalent to the reference product.The three two-drug FDCs （formulations B,C and D） displayed inferior RFP bioavailability compared with the reference （Chinese Clinical Trials registration number：ChiCTR-TTRCC-12002451）.

Head-to-head comparison of the test performance of selfadministered qualitative vs. laboratory-based quantitative fecal immunochemical tests in detecting colorectal neoplasm

Background:Fecal immunochemical tests(FITs)are the most widely used non-invasive tests in colorectal cancer(CRC)screening.However,evidence about the direct comparison of the test performance of the self-administered qualitative a laboratory-based quantitative FITs in a CRC screening setting is sparse.Methods:Based on a CRC screening trial(TARGET-C),we included 3144 pre-colonoscopy fecal samples,including 24 CRCs,230 advanced adenomas,622 non-advanced adenomas,and 2268 participants without significant findings at colonoscopy.Three selfadministered qualitative FITs(Pupu tube)with positivity thresholds of 8.0,14.4,or 20.8 mg hemoglobin(Hb)/g preset by the manufacturer and one laboratory-based quantitative FIT(OC-Sensor)with a positivity threshold of 20 mg Hb/g recommended by the manufacturer were tested by trained staff in the central laboratory.The diagnostic performance of the FITs for detecting colorectal neoplasms was compared in the different scenarios using the preset and adjusted thresholds(for the quantitative FIT).Results:At the thresholds preset by the manufacturers,apart from the qualitative FIT-3,significantly higher sensitivities for detecting advanced adenoma were observed for the qualitative FIT-1(33.9%[95%CI:28.7–39.4%])and qualitative FIT-2(22.2%[95%CI:17.7–27.2%])compared to the quantitative FIT(11.7%[95%CI:8.4–15.8%]),while at a cost of significantly lower specificities.However,such difference was not observed for detecting CRC.For scenarios of adjusting the positivity thresholds of the quantitative FIT to yield comparable specificity or comparable positivity rate to the three qualitative FITs accordingly,there were no significant differences in terms of sensitivity,specificity,positive/negative predictive values and positive/negative likelihood ratios for detecting CRC or advanced adenoma between the two types of FITs,which was further evidenced in ROC analysis.Conclusions:Although the self-administered qualitative and the laboratory-based quantitative FITs had varied test performance at the positivity thresholds preset by the manufacturer,such heterogeneity could be overcome by adjusting thresholds to yield comparable specificities or positivity rates.Future CRC screening programs should select appropriate types of FITs and define the thresholds based on the targeted specificities and manageable positivity rates.