瞬时弹性成像技术对原发性胆汁性肝硬化、自身免疫性肝炎的鉴别及与肝脏纤维化程度、肝功能的相关性研究

背景目前瞬时弹性成像技术已逐渐应用非酒精性脂肪肝、慢性乙肝等鉴别诊断,但有关其同时鉴别原发性胆汁性肝硬化和自身免疫性肝炎(autoimmune hepatitis,AIH)鲜有研究.目的探讨瞬时弹性成像技术对原发性胆汁性肝硬化、AIH的鉴别及与肝脏纤维化程度、肝功能的相关性.方法选取2020-02/2022-02我院收治的89例原发性胆汁性肝硬化患者作为研究组,同期纳入89例AIH患者作为对照组.统计2组瞬时弹性成像技术参数[肝硬度(liver stiffness measurement,LSM)]、肝功能指标[丙氨酸氨基转移酶(alanine aminotransferase,ALT)、谷草转氨酶(aspartate aminotransferase,AST)、B细胞激活因子(b cell activating factor,BAFF)、Klotho蛋白],Spearman分析LSM值与肝脏纤维化程度、肝功能指标相关性,绘制受试者工作特征(receiver operating characteristic,ROC)曲线分析LSM值、肝功能指标对原发性胆汁性肝硬化、AIH鉴别诊断价值.结果研究组LSM值高于对照组(P<0.05);研究组Ⅲ-Ⅳ期所占比例及血清ALT、AST、BAFF水平高于对照组,Klotho蛋白水平低于对照组(P<0.05);LSM值与肝纤维化程度、ALT、AST、BAFF呈正相关,与Klotho蛋白呈负相关(P<0.05);ROC显示,LSM值诊断原发性胆汁性肝硬化价值的AUC为0.846(95%CI:0.785-0.896),高于ALT、AST、BAFF、Klotho蛋白.结论瞬时弹性成像技术参数与肝脏纤维化程度、肝功能密切相关,对准确鉴别原发性胆汁性肝硬化和AIH,尚需进一步研究,探索鉴别诊断参数值.

LncRNA LINC01224/miR-513b-5p对结肠癌细胞SW1116增殖、迁移及侵袭的影响

背景我国结肠癌发病率与死亡率逐年上升,目前结肠癌的发病机制尚未阐明,LncRNA在结肠癌等肿瘤发生过程中可发挥重要调控作用,其主要通过竞争性结合miRNA而发挥作用,已知LncRNA LINC01224在肿瘤中可能发挥癌基因作用,但LINC01224在结肠癌形成及发展过程中的作用机制尚未阐明.目的探讨LncRNA LINC01224/miR-513b-5p对结肠癌细胞SW1116增殖、迁移、侵袭的影响及其可能作用机制.方法采用qRT-PCR法检测癌旁组织与结肠癌组织中LINC01224、miR-513b-5p的表达量;si-NC、si-LINC01224、si-LINC01224与anti-miR-NC、si-LINC01224与anti-miR-513b-5p分别转染入人结肠癌细胞SW1116;采用qRT-PCR法检测SW1116细胞中LINC01224、miR-513b-5p的表达量;采用MTT实验检测细胞存活率;应用流式细胞仪检测细胞周期;采用Transwell小室实验检测细胞迁移及侵袭;双荧光素酶报告实验检测LINC01224与miR-513b-5p的靶向关系;Western blot法检测E-cadherin、N-cadherin蛋白表达量.结果与癌旁组织比较,结肠癌组织中LINC01224的表达水平升高(P<0.05),miR-513b-5p的表达水平降低(P<0.05);与si-NC组比较,si-LINC01224组细胞存活率降低(P<0.05),G0-G1期细胞比例升高(P<0.05),S期细胞比例降低(P<0.05),迁移及侵袭细胞数减少(P<0.05),E-cadherin蛋白水平升高(P<0.05),N-cadherin蛋白水平降低(P<0.05);双荧光素酶报告实验证实LINC01224可靶向结合miR-513b-5p;与si-LINC01224+anti-miR-NC组比较,si-LINC01224+antimiR-513b-5p组细胞存活率升高(P<0.05),G0-G1期细胞比例降低(P<0.05),S期细胞比例升高(P<0.05),迁移及侵袭细胞数增多(P<0.05),E-cadherin蛋白水平降低(P<0.05),N-cadherin蛋白水平升高(P<0.05).结论干扰LINC01224表达可通过上调miR-513b-5p而减弱结肠癌细胞增殖、迁移及侵袭能力,并可诱导细胞周期阻滞于G0-G1期.

Proprotein convertase 1/3-mediated down-regulation of brain-derived neurotrophic factor in cortical neurons induced by oxygen-glucose deprivation

Brain-derived neurotrophic factor(BDNF)has robust effects on synaptogenesis,neuronal differentiation and synaptic transmission and plasticity.The maturation of BDNF is a complex process.Proprotein convertase 1/3(PC1/3)has a key role in the cleavage of protein precursors that are directed to regulated secretory pathways;however,it is not clear whether PC1/3 mediates the change in BDNF levels caused by ischemia.To clarify the role of PC1/3 in BDNF maturation in ischemic cortical neurons,primary cortical neurons from fetal rats were cultured in a humidified environment of 95%N_2 and 5%CO_2 in a glucose-free Dulbecco's modified Eagle's medium at 37℃for3 hours.Enzyme-linked immunosorbent assays and western blotting showed that after oxygen-glucose deprivation,the secreted and intracellular levels of BDNF were significantly reduced and the intracellular level of PC1/3 was decreased.Transient transfection of cortical neurons with a PC1/3 overexpression plasmid followed by oxygen-glucose deprivation resulted in increased PC1/3 levels and increased BDNF levels.When levels of the BDNF precursor protein were reduced,the concentration of BDNF in the culture medium was increased.These results indicate that PC 1/3 cleavage of BDNF is critical for the conversion of pro-BDNF in rat cortical neurons during ischemia.The study was approved by the Animal Ethics Committee of Wuhan University School of Basic Medical Sciences.

Transitional care for patients with chronic obstructive pulmonary disease

Objectives:To observe the effects of transitional care on the quality of life of chronic obstructive pulmonary disease(COPD)patients.Methods:A total of 114 COPD patients were recruited from the First Affiliated Hospital,Sun Yat-sen University,Guangzhou,China and divided equally into an intervention group and control group.Following discharge,patients from the intervention group recieved threemonths intervention in addition to regular nursing care,while control group patients received regular nursing care only.Patients’quality of life was measured using the St.George’s respiratory questionnaire(SGRQ),the 12-item General Health Questionnaire(GHQ-12)and body mass index(BMI).Results:The symptoms section score,the activity section score,the impacts section score,the total score and the rate of mental disorders were significantly changed after the intervention while there was no statistical difference in BMI between groups.Conclusions:Transitional care can improve health-related quality of life in COPD patients who have recently suffered an exacerbation.

LRRK2G2019S Mutation Inhibits Degradation of α-Synuclein in an In Vitro Model of Parkinson's Disease

The G2019S mutation of the leucine-rich repeat kinase 2(LRRK2)is the most common genetic cause of Parkinson's disease (PD).However,the molecular mechanisms of LRRK2 mutation contributing to the onset and progression of PD have not been fully illustrated.We generated HEK293 cells stably transfected with α-synuclein and investigated the effect of LRRK2 G2019S mutation on the degradation of α-synuclein.The lysosomal activity was assessed by the protein degradation of glyceraldehyde-3-phosphate dehydrogenase and ribonuclease A.It was found that α-synuclein was mainly degraded in lysosomes.LRRK2G2019S inhibited the degradation of α-synuclein,and promoted its aggregation.LRRK2G 2019S also decreased the activities of lysosomal enzymes including cathepsin B and cathepsin L.Furthermore,the inhibitory effect of LRRK2 G2019S on lysosomal functions did not depend on its kinase activity.These findings indicated that the inhibitory effect of LRRK2 G2019S on α-synuclein degradation could underlie the pathogenesis of aberrant α-synuclein aggregation in PD with LRRK2 mutation.

Effect of heat treatment on microstructural evolution,mechanical properties and tribological properties of H13 steel prepared using selective laser melting

H13 tool steel was successfully prepared by selective laser melting(SLM)technology.The effects of heat treatment on the microstructure,mechanical properties,and tribological properties of SLMed H13 steel were investigated.The heat treatment process involved a solution treatment and a double aging treatment of the deposited H13 tool steel prepared by SLM.The aim is to optimize the microstructure and mechanical properties of SLMed H13 steel.Due to the rapid heating and cooling effects of SLM,carbide precipitation in the deposited H13 steel was not uniform and residual stresses were present.The purpose of the solution treatment is to dissolve the solution at a high temperature to eliminate the residual stresses and defects introduced by the SLM-forming structure.The solution treatment and first aging treatment produced the precipitation of small carbides at the grain boundaries and inside the crystals,which increased the hardness of SLMed H13 steel.The hardness increased from 538±4.0 HV of the as-deposited sample to 548±5.8 HV of samples after the first aging treatment.Accordingly,the ultimate tensile strength and the elongation at break decreased from 1882 MPa and 11.5%in the as-deposited sample to 1697 MPa and 7.9%in those after the first aging treatment,respectively.Furthermore,the friction coefficient and wear rate in the as-deposited sample decreased from 0.5160 and 2.36×10^(–6)mm^(−3)N^(−1)m^(−1)to 0.4244 and 1.04×10^(–6)mm^(−3)N^(−1)m^(−1),respectively.However,the distribution of carbides inside the crystals was not uniform.The second aging treatment adjusted the morphology of carbide precipitation and made it more uniform,but the precipitation of carbides grew and settled at the bottom of the grain boundaries.The hardness decreased to 533±6.7 HV compared with that with the first aging treatment,but the ultimate tensile strength and plasticity reached a balance(1807 MPa,14.05%).Accordingly,the friction coefficient and wear rate also showed a stable and decreasing trend(0.4407,0.98×10^(–6)mm^(−3)N^(−1)m^(−1)).

Silicone/graphene oxide co-cross-linked aerogels with wide-temperature mechanical flexibility,super-hydrophobicity and flame resistance for exceptional thermal insulation and oil/water separation

Development of multifunctional and high-performance silicone aerogel is highly required for various promising applications.However,unstable cross-linking structure and poor thermal stability of silicone network as well as complicated processing restrict the practical use significantly.Herein,we report a facile and versatile ambient drying strategy to fabricate lightweight,wide-temperature flexible,super-hydrophobic and flame retardant silicone composite aerogels modified with low-content functionalized graphene oxide(FGO).After optimizing silane molecules,incorporation ofγ-aminopropyltriethoxysilane functionalization is found to promote the dispersion stability of GO during the hydrolysis-polymerization process and thus produce the formation of unique strip-like co-cross-linked network.Consequently,the aerogels containing∼2.0 wt%FGO not only possess good cyclic compressive stability under strain of 70%for 100 cycles and outstanding mechanical reliability in wide temperature range(from liquid nitrogen to 350℃),but also display excellent flame resistance and super-hydrophobicity.Further,the optimized silicone/FGO aerogels display exceptional thermal insulating performance superior to pure aerogel and hydrocarbon polymer foams,and they also show efficient oil absorption and separation capacity for var-ious solvents and oil from water.Clearly,this work provides a new route for the rational design and development of advanced silicone composite aerogels for multifunctional applications.

Compressive Behavior of Porous Titanium Fiber Materials

Porous titanium fiber materials with the fiber sizes of 70--120 μm in diameter were prepared by vacuum sintering technology. The morphology and compressive properties of porous titanium fiber materials were investigated by using a scanning electron microscope （SEM） and an MST 858 compression testing machine in quasi-static condition. The results show that porous titanium fibers form complex micro-networks. The stress-strain curves of por- ous titanium fiber materials exhibit elastic region, platform region and densification region and no collapse during platform region. The yield strength of porous titanium fiber materials decreases with increasing the porosity and increasing the fiber diameter.

Sintering Behavior of Porous Titanium Fiber Materials

The porous titanium fiber materials with open porosity were successfully prepared by the vacuum sintering technology. The morphology characteristics of sintering neck of porous titanium fiber materials were investigated by scanning electron microscopy （SEM）. The results show that the formation and growth of sintering neck of porous ti- tanium fiber material approximately follow the rule that the primary mechanism is grain boundary diffusion and sub- sidiary mechanisms are other diffusion mechanisms during the sintering process. The formation and growth of the sintering neck depend mainly on the sintering temperature and slightly on the soaking time. The sintering system of porous titanium fiber material was determined and the equation of the sintering neck＇s length was established.

Effect of hydrogen addition on compression deformation behaviour of Ti-0.3Mo-0.8Ni alloy argon-arc welded joints

The effect of hydrogen addition on compression deformation behaviour of Ti-0.3Mo-0.8Ni alloy argon-arc welded joint has been investigated.Evolution mechanism of hydrogen-induced flow stress was discussed in detail.The results show that with increasing hydrogen content,the stretching and bending extent of fully lamellar microstructures including ot lamellas and acicular hydride continued to increase,the morphology of dynamic recrystallization(DRX)grains tended to change from approximately equiaxed to large lamellar shape,and the quantity of DRX grains and recrystallization degree of grains increased obviously.A large number of dislocations concentrated in the vicinity of the hydride.Steady stress was decreased continuously with increasing hydrogen content,while peak stress of the hydrogenated 0.12 wt.% H weld zone was decreased to the minimum value and then increased slowly.A slight decrease in flow stress of the hydrogenated 0.05 wt.% H weld zone was caused by limited increase in the volume fraction of softer βphase.Hydrogen-induced DRX of a phase and improved dislocation movement by strong interaction between the hydride and dislocation directly resulted in a sharp drop in flow stress of the hydrogenated 0.12 and 0.21 wt.% H weld zone.Solute hydrogen also finitely contributed to a sharp drop in flow stress of the hydrogenated 0.12 and 0.21 wt.% H weld zone by promoted local softening,which induced continuous DRX and more movable dislocations to participate in slipping or climbing.The reinforcement effect and plastic deformation of the hydride and solution strengthening of P phase induced by solute hydrogen finally led to the increase in flow stress of the hydrogenated 0.21 wt.% H weld zone in its true strain range from 0 to 0.36.

Heat transfer performance of porous titanium

Porous titanium fibre materials with different structural parameters were prepared by vacu- um sintering method. The thickness, porosity and wire diameter of prepared materials were investigated to understand the effects of structural parameters on pool heat transmission performance of titanium fibre porous material. As a result, better heat transfer performance is obtained when overheating is less than 10 ℃. In addition, when the wire diameter is smal- ler, the heat transfer is better. However, when superheating is above 10 ℃, heat transfer performance can be improved by increasing the wire diameter. Moreover, thickness influ- ences the superficial area of the prepared material and affects the thermal resistance when bubbles move inside the material; superficial area and thermal resistance are the two key factors that jointly impact the heat transfer in relation to the thickness of the materials. Ex- perimental results also show that the materials of 3 mm in thickness exhibit the best per formance for heat transmission. Furthermore, changes in porosity affect the nucleation site density and the resistance to bubble detachment; however, the nucleation site density and the resistance to bubble detachment conflict with each other. In summary, the titanium fi- bre porous material with a 50% porosity exhibits suitable heat transfer performance.