The Effect of Lattice Misfits on the Precipitation at Dislocations: Phase-Field Crystal Simulation.

An atomic-scale approach was employed to simulate the formation of precipitates with different lattice misfits in the early stages of the aging of supersaturated aluminum alloys. The simulation results revealed that the increase in lattice misfits could significantly promote the nucleation rate of precipitates, which results in a larger number and smaller size of the precipitates. The morphologies of the precipitates also vary with the degree of a lattice misfit. Moreover, the higher the lattice misfit, the earlier the nucleation of the second phase occurs, which can substantially inhibit the movement of dislocations. The research on the lattice misfit of precipitation can provide theoretical guidance for the design of high-strength aluminum alloys.

Atomic-Scale Insights into the Deformation Mechanism of the Microstructures in Precipitation-Strengthening Alloys.

Clarifying the deformation behaviors of microstructures could greatly help us understand the precipitation-strengthening mechanism in alloys. However, it is still a formidable challenge to study the slow plastic deformation of alloys at the atomic scale. In this work, the phase-field crystal method was used to investigate the interactions between precipitates, grain boundary, and dislocation during the deformation processes at different degrees of lattice misfits and strain rates. The results demonstrate that the pinning effect of precipitates becomes increasingly strong with the increase of lattice misfit at relatively slow deformation with a strain rate of 10-4. The cut regimen prevails under the interaction between coherent precipitates and dislocations. In the case of a large lattice misfit of 19.3%, the dislocations tend to move toward the incoherent phase interface and are absorbed. The deformation behavior of the precipitate-matrix phase interface was also investigated. Collaborative deformation is observed in coherent and semi-coherent interfaces, while incoherent precipitate deforms independently of the matrix grains. The faster deformations (strain rate is 10-2) with different lattice misfits all are characterized by the generation of a large number of dislocations and vacancies. The results contribute to important insights into the fundamental issue about how the microstructures of precipitation-strengthening alloys deform collaboratively or independently under different lattice misfits and deformation rates.

Glutamate-releasing BEST1 channel is a new target for neuroprotection against ischemic stroke with wide time window

Many efforts have been made to understand excitotoxicity and develop neuroprotectants for the therapy of ischemic stroke. The narrow treatment time window is still to be solved. Given that the ischemic core expanded over days, treatment with an extended time window is anticipated. Bestrophin 1 (BEST1) belongs to a bestrophin family of calcium-activated chloride channels. We revealed an increase in neuronal BEST1 expression and function within the peri-infarct from 8 to 48 h after ischemic stroke in mice. Interfering the protein expression or inhibiting the channel function of BEST1 by genetic manipulation displayed neuroprotective effects and improved motor functional deficits. Using electrophysiological recordings, we demonstrated that extrasynaptic glutamate release through BEST1 channel resulted in delayed excitotoxicity. Finally, we confirmed the therapeutic efficacy of pharmacological inhibition of BEST1 during 6-72 h post-ischemia in rodents. This delayed treatment prevented the expansion of infarct volume and the exacerbation of neurological functions. Our study identifies the glutamate-releasing BEST1 channel as a potential therapeutic target against ischemic stroke with a wide time window.

Research advances of tofacitinib in the treatment of ulcerative colitis / 中国药房

Ulcerative colitis （UC）is a chronic inflammatory bowel disease caused by multiple factors ，and its etiology and pathogenesis remain unclear . Tofacitinib，a small molecule rapidly absorbed by oral administration ，treats UC primarily by inhibiting Janus kinase （JAK）. Tofacitinib has been approved by the FDA and the European Medicines Agency for the treatment of moderate to severe UC . Many clinical studies on tofacitinib in the treatment of UC have been carried out abroad ，but there is no relevant report on its use in UC in China . This paper summarizes the relevant research advances of tofacitinib in the treatment of UC from its mechanism ，clinical application and safety . The results show that tefatinib mainly treats UC by inhibiting the expression of JAK and proinflammatory factors , regulating the overexpressed signaling transducers and activators of transcription , and repairing the intestinal mucosal barrier . Tofacitinib has good clinical efficacy ，but safety studies have shown that the risks of herpes zoster and thrombosis should not be ignored ，and the drug should be used with caution in pregnant ，children，adolescents， and elderly patients . The efficacy and safety of tofacitinib in Chinese population should be further studied in the future ，since it has not been used in UC patients in China .

Progress in Studies on Diagnosis and Surgical Treatment of Refractory Ulcerative Colitis / 胃肠病学

Ulcerative colitis (UC) is a chronic immune-mediated gastrointestinal inflammatory disease, the etiology has not been fully clarified. As a developing and emerging industrialized country, China is about to enter or has entered the stage of ' accelerated incidence rate and compound epidemic' of UC. Evaluate the clinical condition of refractory ulcerative colitis (RUC) at its early stage and select appropriate treatment is important. Although the kinds of drug become more and more, the rate of colon resection remains unchanged. When drug therapy cannot improve the symptoms of patient, surgical treatment should be considered. This article reviewed the progress in studies on diagnosis and surgical treatment of RUC.

Visual improvement of therapeutic plasma exchange for refractory optic neuritis patients in acute phase / 中华眼底病杂志

Objective To evaluate the visual improvement of therapeutic plasma exchange (TPE) for refractory optic neuritis (ON) patients in acute phase.Methods Seventy-five affected eyes from 44 refractory ON patients with severe visual defect or resistance to high-dose intravenous methylprednisolone (IVMP) therapy,who were admitted to The Chinese PLA General Hospital between January 2015 and August 2016,were recruited and received TPE therapy.Among these patients,11 were male and 33 were female;the average age was 39.1 ± 13.9;31 patients had two affected eyes,13 patients had one affected eye.The course of the disease on the group of patients were more than 2 weeks,and the visual acuity worsened for more than 10 days and continued to deteriorate.TPE treatment was performed on all of the patients.BCVA was recorded before and 24 h after treatment,and the visual function was scored using visual outcome scale (VOS).At the same time,the adverse reactions of TPE treatment were observed.The paired t-test was used to compare the VOS before and after treatment.The correlation between VOS before and after treatment was analyzed by Linear-by-Linear correlation analysis.Results Among 75 affected eyes,the post-therapy VOS 3.89 ±2.13 was significantly improved from pre-therapy VOS 5.56± 1.69 (t=6.77,P＜0.001).Forty-eight of 75 eyes were improved at lease 1 score of VOS,the overall rate of visual improvement was 64.0％.Especially among the eyes with initial vision of light perception,an improved rate of 82.4％ was presented.75.0％ in those eyes with initial vision of count fingers and 67.7％ in no light perception.Linear-by-Linear correlation analysis showed a significant linear correlation between the scores of VOS before and after TPE treatment (r=0.398,P=0.01).During the course of TPE treatment,5 patients had mild adverse reactions such as low calcium reaction and allergic reaction and were well controlled after treatment.Conclusion Using TPE to treat refractory ON in acute phased can improve the visual function of patients.

Preparation and characterization of laser-melted Mg-Sn-Zn alloys for biomedical application.

The rapid degradation rate of Magnesium (Mg) alloy limits its biomedical application even though it possesses outstanding biological performance and biomechanical compatibility. In this study, a combined method of laser rapid melting and alloying Zinc (Zn) was proposed to decrease the degradation rate of Mg-Sn alloy. The microstructure, degradation behaviors and mechanical properties of the laser-melted Mg-5Sn-xZn (x = 0, 2, 4, 6 and 8 wt.%) alloys were investigated. The results indicated that the grain size of the alloys decreased with increasing Zn content, due to the increased number of nucleation particles formed in the process of solidification. Moreover, the laser-melted Mg-Sn alloys possessed finer grains compared with traditional as-cast and as-rolled Mg-Sn alloys. The degradation rate of the alloys decreased with increasing Zn content (0-4 wt.%), which was ascribed to the grain refinement and the formation of Zn(OH)2 protective layer. However, the degradation rate increased as the Zn content further increased (4-8 wt.%), which was caused by the galvanic corrosion between the Mg matrix and the generated Mg7Zn3 phase. Besides, Zn also increased the hardness of the alloys owing to the grain refinement strengthening and solid solution strengthening.

Tailoring properties of porous Poly (vinylidene fluoride) scaffold through nano-sized 58s bioactive glass.

The biological properties of porous poly (vinylidene fluoride) (PVDF) scaffolds fabricated by selective laser sintering were tailored through nano-sized 58s bioactive glass. The results showed that 58s bioactive glass distributed evenly in the PVDF matrix. There were some exposed particles on the surface which provided attachment sites for biological response. It was confirmed that the scaffolds had highly bioactivity by the formation of bone-like apatite in simulated body fluid. And the bone-like apatite became dense with the increase in 58s bioactive glass and culture time. Moreover, the scaffolds were suitable for cell adhesion and proliferation compared with the PVDF scaffolds without 58s bioactive glass. The research showed that the PVDF/58s bioactive glass scaffolds had latent application in bone tissue engineering.