基于机器学习的Al-Zn-Mg-Cu合金快速设计

提出一种基于机器学习的合金快速设计系统(ARDS),以定制所需性能的合金制备策略或预测制备策略所对应的合金性能。为此,分别对3种回归算法:线性回归(LR)、支持向量回归(SVR)和人工神经网络(BPNN)进行建模和比较以训练多性能预测模型。其中,应用SVR构建的机器学习模型被证明是最佳的。然后,基于生成对抗网络(GAN)模型原理,构建Al-Zn-Mg-Cu系铝合金快速设计系统(ARDS)。对ARDS的预测可靠性进行验证。结果表明,为了能够获得准确的制备策略,系统中极限抗拉强度(UTS)、屈服强度(YS)和伸长率(EL)的输入上限分别约为790 MPa、730 MPa和28%。此外,基于ARDS预测结果,制备了一种性能优异的新型铝合金材料,其UTS为764 MPa、YS为732 MPa、EL为10.1%,进一步验证了ARDS的可靠性。

利用577nm阈值下微脉冲激光治疗糖尿病性黄斑水肿

目的:探讨利用577nm阈值下微脉冲激光治疗糖尿病性黄斑水肿(DME)的临床效果。方法:回顾性分析48例64眼DME患者临床资料,行577nm阈值下微脉冲激光术者26例35眼,行传统格栅样激光术者22例29眼。比较术前及术后1、3、6mo时BCVA(LogMAR)、黄斑中心凹视网膜厚度(CFT)、平均光敏感度(MS)及平均视野缺损(MD)变化,分析两组患者眼底硬性渗出持续时间及并发症。结果:术后1、3、6mo时,两组视力(0.30±0.09 vs 0.35±0.10、0.19±0.07 vs 0.26±0.09、0.13±0.04 vs 0.18±0.05)及CFT (349.26±21.80μm vs 364.37±23.91μm、314.46±20.49μm vs 335.07±22.68μm、328.35±21.74μm vs 352.43±23.60μm)均较术前下降,且观察组明显低于同一时间对照组(均P<0.05);观察组MS、MD水平均较术前提升,且明显高于同一时间对照组5.83±1.16dB vs 4.22±1.04dB、6.38±1.29dB vs 4.49±1.17dB、6.75±1.22dB vs 4.68±1.20dB,-5.53±1.41dB vs-7.66±1.52dB、-5.09±1.30dB vs-7.26±1.39dB、-4.68±1.14dB vs-7.05±1.26dB)(均P<0.05)。观察组眼底硬性渗出持续时间明显少于对照组(3.39±0.80mo vs 4.25±1.14mo)(P<0.05)。术后6mo内,观察组眼球疼痛发生率明显低于对照组[3%(1/35)vs 24%(7/29)](P<0.05),而前房炎性反应、视野缺损、高眼压及角膜水肿发生率比较均无差异(P>0.05)。结论:577nm阈值下微脉冲激光术治疗DME安全有效。

Impact of Laparoscopic Versus Open Hepatectomy on Perioperative Clinical Outcomes of Patients with Primary Hepatic Carcinoma

Objective To compare the perioperative outcomes of patients with primary hepatic carcinoma treated with laparoscopic hepatectomy(LH) with those treated with open hepatectomy(OH). Methods From January 2010 to August 2014, 100 patients with primary hepatic carcinoma were randomly divided into the LH group and OH group respectively, 50 patients in each group. And the incision length, blood loss, operative time, postoperative liver function, anus exhaust time, complications, length of postoperative hospital stay, and cost measures were compared. Results LH could achieve shorter incision length, less blood loss, more rapid recovery in liver function and gastrointestinal function, and shorter postoperative hospital stay length compared with OH for primary hepatic carcinoma patients(all P<0.05). However, LH could not significantly shorten operative time, and reduce postoperative complications and hospitalization cost(all P>0.05). Conclusion Compared with OH, LH could improve perioperative outcomes of primary hepatic carcinoma patients.

Texture and stretch formability of rolled Mg–Zn–RE(Y, Ce, and Gd) alloys at room temperature

To develop a new magnesium alloy with excellent formability at room temperature, the effect of Y, Ce, and Gd addition on texture and stretch formability of Mg-1.5Zn alloys was carried out. The result shows that Y, Ce, and Gd addition in Mg-1.5Zn alloys can effectively weaken and modify the basal plane texture, characterized by TD-split texture in which the position of basal is titled from normal direction （ND） toward transverse direction （TD）. When Mg-1.5Zn alloy with Gd addition appears low texture intensity and TD-split texture, where the position of basal poles is tilted by about 4-35° from ND toward to TD, the largest Erichsen value of 7.0 and the elongation rate reaches 29.1% in TD direction. However, Y and Ce addition in Mg-1.5Zn alloys promote a large number of second phase particles, which cancel the contribution of the unique basal texture to stretch formability and ductility.

我国早产儿视网膜病变的筛查现状

早产儿视网膜病变(ROP)是一种属于可避免、可控的儿童主要致盲性及低视力眼病。筛查是早检出、早干预和早治疗的前提和关键措施,对降低儿童致盲率及视力损伤具有重要意义。本文主要对我国ROP筛查和发病现状作一综述,以期为ROP的防治提供参考。

Element distribution and difusion behavior in Q&P steel during partitioning

Carbon, manganese, and silicon distribution in quenching and partitioning （Q＆P） steel during partitioning process was investigated to reveal the diffusion behavior. The microstructure and chemical composition were analyzed by means of scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, and three-dimensional atom probe. It is shown that the studied Q＆P steel consisted of martensite laths and thin, film-like retained austenite showing extraordinary phase transformation stability. Carbon atoms mostly diffused to the retained austenite from martensite at a higher partitioning temperature. In the experimental steel partitioned at 400℃ for 10-60 s, carbides or cementite formed through carbon segregation along martensite boundaries or within the martensite matrix. As a result of carbon atom diffusion from martensite to austenite, the carbon content in martensite could be ignored. When the partitioning process completed, the constrained carbon equilibrium （CCE） could be simplified. Results calculated by the simplified CCE model were similar to those of CCE, and the difference between the two optimum quenching temperatures, where the maximum volume fraction of the retained austenite can be obtained by the Q＆P process, was little.

Influence of Photodynamic Therapy on Apoptosis and Invasion of Human Cholangiocarcinoma QBC939 Cell Line

Objective To investigate the effect of photodynamic therapy(PDT) mediated by hematoporphyrin derivative(HPD) on apoptosis and invasion of cholangiocarcinoma QBC939 cell lines. Methods In vitro cultured cholangiocarcinoma QBC939 cell line was exposed to 2, 4, 6, 8, 10, 12, and 14 μg/ml HPD with 5, 10, and 15 J/cm2 light intensity, respectively. The optical density at 450 nm of the QBC939 cells was measured by CCK8 assay and its growth inhibition ratio was calculated. Flow cytometry and transwell migration assay were applied to detect cell apoptosis and invasion respectively. RT-PCR and immunocytochemistry analyses were used to detect expressions of vascular endothelial growth factor-C(VEGF-C), cyclooxygenase-2(COX-2), and proliferating cell nuclear antigen(PCNA). Enzyme-linked immunosorbent assay(ELISA) was carried out to examine the secretion of VEGF-C and COX-2 in QBC939 cells. Results Exposure to HPD-PDT can significantly suppress the growth of QBC939 cells(all P<0.05). HPD-PDT can promote apoptosis of QBC939 cells at the early stage. When the concentration of HPD was 2 μg/ml and light irradiation was 5 J/cm2, HPD-PDT had no obvious inhibitory effect on QBC939 cell growth, but can obviously inhibit cell invasion, and significant difference was observed between the HPD-PDT and control groups(P<0.01). The HPD-PDT can reduce the m RNA and protein expressions of VEGF-C, COX-2, and PCNA, and decrease the secretion of VEGF-C and COX-2 in QBC939 cells. Conclusion PDT could promote apoptosis and inhibit growth and invasion of cholangiocarcinoma cells QBC939 in vitro.

Effect of interface morphology on the mechanical properties of titanium clad steel plates

Interface morphology has important influence on the bond quality of titanium clad steel plates. The mechanical properties of titanium clad steel plates with wavy and straight interfaces were investigated by tensile-shear tests and bending tests. The interface morphology of the plates was examined by optical microscopy （OM） and scanning electron microscopy （SEM）. The experimental results show that the shear strength of a wavy interface is higher than that of a straight interface. A wavy interface is the guarantee for obtaining high shear strength to provide a greater shear resistance. During the maerobending process, cracks appear in the swirl of the wave tip and ferrotitanium intermetallies. For in-situ observing the bending process by SEM, the wave tip of a wavy interface and the massive ferrotitartium intermetallies of a straight interface are places where cracks initiate and propagate. The results are the same as those observed in the macrobending process. Became of high hardness, the wave tip and the massive ferrotitanium intermetallies are hard in terms of compatible deformation.

A novel diffusion model considering curvature radius at the bonding interface in a titanium/steel explosive clad plate

This article introduces an element diffusion behavior model for a titanium/steel explosive clad plate characterized by a typical curved interface during the heat-treatment process. A series of heat-treatment experiments were conducted in the temperature range from 750℃ to 950℃, and the effects of heat-treatment parameters on the microstructural evolution and diffusion behavior were investigated by optical microscopy, scanning electron microscopy, X-ray diffraction analysis, and electron-probe microanalysis. Carbon atoms within the steel matrix were observed to diffuse toward the titanium matrix and to aggregate at the bonding interface at 850℃ or lower; in contrast, when the temperature exceeded 850℃, the mutual diffusion of Ti and Fe occurred, along with the diffusion of C atoms, resulting in the for- marion of Ti-Fe intermetallics （Fe2Ti/FeTi）. The diffusion distances of C, Ti, and Fe atoms increased with increasing heating temperature and/or holding time. On the basis of this diffusion behavior, a novel diffusion model was proposed. This model considers the effects of various factors, including the curvature radius of the curved interface, the diffusion coefficient, the heating temperature, and the holding rime. The experimental results show good agreement with the calculated values. The proposed model could clearly provide a general prediction of the elements＇ diffusion at both straight and curved interfaces.

Research and development of 780 MPa cold rolling TRIP-aided steel

As an industry-university cooperative project, an experimental research was conducted to develop a new cold-rolled transformation-induced plasticity （TRIP） steel with a tensile strength of 780 MPa and an elongation of 25% under the conditions that some processing parameters were preestablished according to the actual conditions of factory production lines. The optimal heat treatment conditions for obtaining excellent strength-ductility balance, specifically in intercritical annealing temperature and isothermal treatment temperature, were investigated by means of thermal simulation tests. Ultimately the desirable mechanical properties were attained successfully, and the microstructure and retained austenite stability were studied by optical microscopy （OM） and electron back-scattered diffraction （EBSD）. It has been discovered that the sizes of retained austenite grains are generally proportional to the sizes of carbon-clear space （ferrite and bainite） around them, and there is marked selectivity in their transition sequences under stress-strain.

Characterizations of precipitation behavior of Al-Mg-Si alloys under different heat treatments

The solidification-precipitation behavior of Al-Mg-Si multicomponent alloys has long been an absorbing topic. Experiments were carried out to analyze the precipitation behaviors of Al-Mg-Si alloys under different heat treatments. All specimens were homogenized at 570 ℃ for 8 h, and then solution treated at 540 ℃ for 55 min. Subsequently, the specimens were age treated for different times at temperatures of 100 ℃, 150 ℃ and 180 ℃, respectively. The experimental results show that the occurrence of dispersed free zones （DFZ） is caused by the uneven distribution of dispersed phase. During the aging process, pre-β＂ phases form at the initial stage and an aging temperature of 100 ℃is too low to complete the transformation of pre-β＂ to β＂. At 150℃, the precipitation sequence is concluded as SSSS-pre-β＂-pre-β＂＋β＂-β＂-β＇-β. Moreover, changes in sizes and densities of the pre-β＂, β＂and β＇ phases during the aging process has an important influence on the evolution of microhardness and electrical resistivity. The microhardness peak value of 150 ℃ is similar to that of 180 ℃, which is -141 HV. While, at 100℃, the microhardness increases slowly, and the attainable value is 127 HV up to 19 days. When the aging temperature is 100 ℃, the electrical resistivity has the highest average value. When the aging temperature exceeds 100 ℃, with the occurrence and growth of β＂and β＇, the resistivity has a distinct decrease with prolonged aging time.

Prediction of mushy zone permeability of Al-4.5wt%Cu alloy during solidification by phase field model and CFD simulation

Liquid permeability of the mushy zone is important for porosity formation during the solidification process. In order to investigate the permeability of the mushy zone, an integrated model was developed by combining the phase field model and computational fluid dynamics (CFD) model. The three-dimensional multigrain dendrite morphology was obtained by using the phase field model. Subsequently, the computer-aided design (CAD) geometry and mesh were generated based on calculated dendrite morphologies. Finally, the permeability of the dendritic mushy zone was obtained by solving the Navier-Stokes and continuity equations in ANSYS Fluent software. As an example, the dendritic mushy zone permeability of Al-4.5wt%Cu alloy and its relationship with the solid fractions were studied in detail. The predicted permeability data can be input to the solidification model on a greater length scale for macro segregation and porosity simulations.

Synthesis of thorium sol for fabricating fuel kernels

To fabricate thorium-based fuel kernel for solid fuel molten salt reactor,a component of tri-structural isotropic fuel particles is mostly based on sol-gel method.The preparation of thorium sol is an important step for fabrication of thorium-based fuel kernels,such as thorium carbide and thorium oxide.The gel quality affects the gel particle dispersion and the final products.In this work,thorium sols were prepared using Th(NO_3)_4 and NH_3·H_2O by sol-gel method.The effects of thorium concentration,mole ratio of NH_4^+/NO_3^- and reaction temperature on the pH,viscosity,turbidity,particle size and the thorium sol distribution were investigated.The results show that the viscosity and turbidity increased with the NH_4^+/NO_3^- ratio;the turbidity and colloidal particle size increased with the reaction temperature,which affected little the sol viscosity;the sol viscosity increased with the thorium concentration,which virtually did not change the turbidity;and the particle size decreased and the size distribution narrowed with increasing thorium concentration.The sol could be stored at room temperature for one day without significant property changes.Thorium gel spheres of good quality were prepared at 60℃ with the NH_4^+/NO_3^- ratio of 75-85% and the thorium concentration of 1.2-1.4 mol/L.

Effect of La addition on microstructure and mechanical properties of hypoeutectic Al-7Si aluminum alloy

The effect of La addition(0,0.1,0.2,0.4,wt.%)on the microstructure,tensile properties and fracture behavior of Al-7Si alloy was investigated systematically.It is found that the La appears in the Al-7Si alloy in the form of Al4La and Al2Si2La phases.La addition can refine the secondary dendrite arm spacing(SDAS)and eutectic Si particles,which are decreased by 7.9%and 7%,respectively,with the optimal La content of 0.1wt.%.Because when 0.1wt.%La is added,a relatively higher nucleation undercooling of 37.47℃ is observed.Higher undercooling degree suggests that nucleation is accelerated and subsequent growth is restrained.After T6 heat treatment,compared with the without La,the ultimate tensile strength of the alloy with 0.1wt.%La is enhanced by 5.2%from 333 MPa to 350.2 MPa and the elongation increases by 73%from 7.37%to 12.75%,correspondingly.The fracture mode evolves from the ductile-brittle mixed fracture to ductile fracture mode.However,when La element content reaches a certain value of 0.4wt.%,serious segregation takes place during the solidification process.The formed brittle phases deteriorate the tensile properties of the alloy and the fracture mode of Al-7Si-0.2/0.4 La changes to mixed ductile-brittle fracture mode.

Behcet’s disease manifesting as esophageal variceal bleeding: A case report

BACKGROUND Behcet’s disease(BD)is a chronic disease characterized by oral and vulvar ulcers as well as eye and skin damage and involves multiple systems.It presents as an alternating process of repeated attacks and remissions.Esophageal venous rupture and bleeding caused by BD is rarely reported at home and abroad.This paper reports a case of bleeding from oesophageal varices caused by BD,aiming to provide an additional dimension for considering the cause of bleeding from esophageal varices in the future.CASE SUMMARY A 38-year-old female patient was admitted due to a gradual increase in shortness of breath and chest tightness after the activity,and was admitted to our hospital for treatment.After admission,relevant examinations showed that the patient had multiple blood clots.Four days after admission,she suddenly experienced massive hematemesis.Emergency esophagogastroduodenoscopy revealed bleeding from esophageal and gastric varices.The patient had no history of viral hepatitis or drinking habits,and no history of special genetic diseases or congenital vascular diseases.There is no obvious abnormality in liver function.After reviewing the medical history,it was found that the patient had recurred oral ulcers since childhood,ulcers were visible in the perineum during menstruation,and there was an intermittent red nodular rash and uveitis.The current skin acupuncture reaction is positive,combined with the evaluation of the external hospital and our hospital,the main diagnosis is BD.She received methylprednisolone,cyclophosphamide,immunomodulation,acid suppression,gastric protection,and anticoagulation and anti-infection treatments,and was discharged from the hospital.During the 1-year follow-up period,the patient did not vomit blood again.CONCLUSION This case highlights bleeding from esophageal varices caused by BD, aiming toprovide an additional dimension concerning the cause of bleeding fromesophageal varices in the future.

小核仁RNA宿主基因5对骨髓间充质干细胞成骨分化和凋亡的影响

目的探究小核仁RNA宿主基因5(SNHG5)在调控骨髓间充质干细胞成骨分化和凋亡中的作用。方法成骨诱导液诱导骨髓间充质干细胞成骨分化,不同质粒转染分组,Western blotting法检测成骨标志物(OCN、OSX、COL1A1)的蛋白相对表达量,茜素红染色和碱性磷酸酶(ALP)检测成骨效果,实时荧光定量聚合酶链反应(qRT-PCR)检测SNHG5和OCN mRNA相对表达量。将细胞随机分为两组,实验组下调SNHG5表达,对照组不下调,同法进行成骨诱导,检测OCN、OSX及COL1A1的蛋白相对表达量,检测成骨效果,检测OCN、OSX、COL1A1及SNHG5 mRNA相对表达量。采用流式细胞术检测细胞凋亡,并检测Caspase-3活性。结果成骨诱导后第14天的OCN、OSX及COL1A1蛋白相对表达量高于诱导后第7天和诱导前(P<0.05),诱导后第7天高于诱导前(P<0.05)。成骨诱导前、诱导后第7天、诱导后第14天的ALP活性和茜素红浓度比较,差异有统计学意义(P<0.05)。成骨诱导前、诱导后第1天、第3天、第5天、第7天、第14天的SNHG5和OCN mRNA相对表达量随时间推移逐渐升高(P<0.05)。转染不同质粒后,各组SNHG5 mRNA相对表达量比较,差异有统计学意义(P<0.05),细胞转染质粒后第14天实验组OCN、OSX及COL1A1 mRNA和蛋白相对表达量低于对照组(P<0.05),细胞转染质粒后第14天实验组ALP活性和茜素红浓度低于对照组(P<0.05),实验组细胞凋亡率和Caspase-3活性高于对照组(P<0.05)。结论SNHG5参与骨髓间充质干细胞成骨分化和凋亡,可能在骨质疏松症的发展中起促进作用,为改善颌骨骨质疏松的治疗提供新靶点。

Relationship of PDCD5 expression with apoptosis, inflammatory factors and MMPs/TIMPs expression in degenerated intervertebral disc tissue

Objective: To study the relationship of PDCD5 expression with apoptosis, inflammatory factors and MMPs/TIMPs expression in degenerated intervertebral disc tissue. Methods:Patients with lumbar disc herniation who were treated in the Seventh People's Hospital of Shanghai between March 2015 and February 2017 were selected as the LDH group and patients with violent thoracolumbar vertebral fracture were selected as the control group. The intervertebral disc tissue was collected to determine the mRNA expression of PDCD5 as well as the protein levels of apoptosis molecules, inflammatory factors and MMPs/TIMPs molecules. Results: PDCD5 mRNA expression in intervertebral disc tissue of LDH group was significantly higher than that of control group;Caspase-3, Caspase-8, Fas, Caspase-9, Bax, SDF-1, CXCR-4, TNF-α, PGE2, MMP1, MMP2, MMP8 and MMP9 protein levels in intervertebral disc tissue of LDH group were significantly higher than those of control group and positively correlated with PDCD5 mRNA expression while TIMP1 and TIMP2 protein levels were significantly lower than those of control group and negatively correlated with PDCD5 mRNA expression. Conclusion: The high expression of PDCD5 in degenerated intervertebral disc tissue can activate apoptosis and inflammatory response and cause MMPs/TIMPs imbalance.

Effect of Alemtuzumab on Intestinal Intraepithelial Lymphocytes and Intestinal Barrier Function in Cynomolgus Model

Background：Alemtuzumab has been used in organ transplantation and a variety of hematologic malignancies （especially for the treatment of B-cell chronic lymphocytic leukemia）.However,serious infectious complications frequently occur after treatment.The reason for increased infections postalemtuzumab treatment is unknown at this stage.We explore the effect ofalemtuzumab on intestinal intraepithelial lymphocytes （IELs） and intestinal barrier function in cynomolgus model to explain the reason of infection following alemtuzumab treatment.Methods：Twelve male cynomolguses were randomly assigned to either a treatment or control group.The treatment group received alemtuzumab （3 mg/kg,intravenous injection） while the control group received the same volume of physiological saline.Intestinal IELs were isolated from the control group and the treatment group （on day 9,35,and 70 after treatment） for counting and flow cytometric analysis.Moreover,intestinal permeability was monitored by enzymatic spectrophotometric technique and enzyme-linked immunosorbent assay.Results：The numbers of IELs were decreased significantly on day 9 after treatment compared with the control group （0.35 ± 0.07 × 10^8 and 1.35 ± 0.09 × 10^8,respectively; P 〈 0.05） and were not fully restored until day 70 after treatment.There were significant differences among four groups considering IELs subtypes.In addition,the proportion ofapoptotic IELs after alemtuzumab treatment was significantly higher than in the control group （22.01 ± 3.67 and 6.01 ± 1.42,respectively; P 〈 0.05）.Moreover,the concentration of D-lactate and endotoxin was also increased significantly on day 9 after treatment.Conclusions：Alemtuzumab treatment depletes lymphocytes in the peripheral blood and intestine of cynomolgus model.The induction of apoptosis is an important mechanism of lymphocyte depletion after alemtuzumab treatment.Notably,intestinal barrier function may be disrupted after alemtuzumab treatment.

Microstructure and Mechanical Properties of TRIP Steel with Annealed Martensite

The microstructure and mechanical properties of cold rolled TRIP steel containing C 0.2, Si 0.5, Mn 1.5, A1 1.3, and Nb-kV 0.13 （mass%） with annealed martensite （TAM steel） were investigated using optical microscopy, field emission gun scanning electronic microscope （FEG SEM）, transmission electron microscopy （TEM）, X-ray diffraction （XRD）, and mechanical testing. The mierostructure of the TAM steel mainly consisted of polygonal ferrite, bainite, annealed martensite and retained austenite. The martensite after annealing did not spheroidize, which consisted of annealed lath martensite structure and interlath second phase. Compared with the traditional TRIP steel with polygonal ferrite matrix （TPF steel）, the TAM steel has more excellent elongation rate over 32%. The TAM steel also has better strain hardening behavior than the TPF steel. The excellent elongation and strain harden- ing behavior of TAM steel result from high retained austenite stability of the TAM steel, which is attributed to its fine distribution and medium strength ratio of second phase to matrix.

Deformation behavior and microstructural evolution in ultra-highstrength dual-phase(UHS-DP1000)steel with different strain rates

The dynamic tensile behavior and deformation mechanism of ultra-high-strength dual-phase(UHS-DP1000)steel were investigated over a wide range of strain rates from 10^-4 to 10^3 s^-1.As the strain rate increases,the transition strain decreases from 2.73 to 1.92,and the martensite plastic deformation starts earlier.At strain rate of 10^-4-0.5 s^-l,the inhomogeneous plastic deformation ability increases because the dislocation density in the ferrite matrix increases.This leads to a decrease in uni form elongation and an increase in fracture elongation.When the strain rate increases from 0.5 to 500s^-l.the amount of mobile dislocation increases,which is the main reason for the enhancing uniform elongation and fracture elongation.Mea nwhile,because the dislocation motio n resistance rapidly in creases,the yield strength and ultimate tensile strength also increase.When the strain rate is higher than 500 s^-1.the hardening behavior caused by the dislocation motion resistance has not been offset by softening due to the mobile dislocation and adiabatic heating.The voids at the early stage of deformation could not uniformly form and grow,and thus the homogeneous plastic deformation ability decreases.