Optimization of the Gas Generator in Composite Power System with Tip-Jet Rotor

The key and bottleneck of research on the tip-jet rotor compound helicopter lies in the power system. Computational Fluid Dynamics (CFD) was used to numerically simulate the gas generator and rotor inner passage of the tip-jet rotor composite power system, studying the effects of intake mode, inner cavity structure, propellant components, and injection amount on the characteristics of the composite power system. The results show that when a single high-temperature exhaust gas enters, the gas generator outlet fluid is uneven and asymmetric;when two-way high-temperature exhaust gas enters, the outlet temperature of the gas generator with a tilted inlet is more uniform than that with a vertical inlet;adding an inner cavity improves the temperature and velocity distribution of the gas generator's internal flow field;increasing the energy of the propellant is beneficial for improving the available moment.

Grain refinement of Mg-Ca alloys by native MgO particles

In Mg-Ca alloys the grain refining mechanism,in particular regarding the role of nucleant substrates,remains the object of debates.Although native MgO is being recognised as a nucleating substrate accounting for grain refinement of Mg alloys,the possible interactions of MgO with alloying elements that may alter the nucleation potency have not been elucidated yet.Herein,we design casting experiments of Mg-xCa alloys varied qualitatively in number density of native MgO,which are then comprehensively studied by advanced electron microscopy.The results show that grain refinement is enhanced as the particle number density of MgO increases.The native MgO particles are modified by interfacial layers due to the co-segregation of Ca and N solute atoms at the MgO/Mg interface.Using aberration-corrected scanning transmission electron microscopy and electron energy loss spectroscopy,we reveal the nature of these Ca/N interfacial layers at the atomic scale.Irrespective of the crystallographic termination of MgO,Ca and N co-segregate at the MgO/Mg interface and occupy Mg and O sites,respectively,forming an interfacial structure of a few atomic layers.The interfacial structure is slightly expanded,less ordered and defective compared to the MgO matrix due to compositional deviations,whereby the MgO substrate is altered as a poorer template to nucleate Mg solid.Upon solidification in a TP-1 mould,the impotent MgO particles account for the grain refining mechanism,where they are suggested to participate into nucleation and grain initiation processes in an explosive manner.This work not only reveals the atomic engineering of a substrate through interfacial segregation but also demonstrates the effectiveness of a strategy whereby native MgO particles can be harnessed for grain refinement in Mg-Ca alloys.

Synergistic effect of gradient Zn content and multiscale particles on the mechanical properties of Al-Zn-Mg-Cu alloys with coupling distribution of coarse-fine grains

This study investigated the influence of graded Zn content on the evolution of precipitated and iron-rich phases and grain struc-ture of the alloys,designed and developed the Al–8.0Zn–1.5Mg–1.5Cu–0.2Fe(wt%)alloy with high strength and formability.With the increase of Zn content,forming the coupling distribution of multiscale precipitates and iron-rich phases with a reasonable matching ratio and dispersion distribution characteristics is easy.This phenomenon induces the formation of cell-like structures with alternate distribu-tion of coarse and fine grains,and the average plasticity–strain ratio(characterizing the formability)of the pre-aged alloy with a high strength is up to 0.708.Results reveal the evolution and influence mechanisms of multiscale second-phase particles and the corresponding high formability mechanism of the alloys.The developed coupling control process exhibits considerable potential,revealing remarkable improvements in the room temperature formability of high-strength Al–Zn–Mg–Cu alloys.

Genome-wide identification and characterization of the PbrATG family in Pyrus bretschneideri and functional analysis of PbrATG1a in response to Botryosphaeria dothidea

The pear is an economic fruit that is widely planted around the world and is loved by people for its rich nutritional value. Autophagy is a self-protection mechanism in eukaryotes, and its occurrence often accompanied by the degradation of damaged substances in cells and the recycling of nutrients. Autophagy is one of the mechanisms through which plants respond to environmental stress and plays an important role in plant development and stress resistance. Functional studies of autophagy-related genes (ATGs) have been performed on a variety of plant species, but little information is available on the ATG family in pear (Pyrus bretschneideri Rehd). Therefore, we analyzed the evolutionary dynamics and performed a genome-wide characterization of the PbrATG gene family. A total of 28 PbrATG members were identified.Phylogenetic analysis showed that PbrATGs were more closely related to ATGs of European pear and apple. Evolutionary analysis revealed that whole-genome duplication (WGD) and dispersed duplication events were the main driving forces of PbrATG family expansion.Expression analysis of different pear tissues showed that all the genes were expressed in different pear tissues, and different PbrATGs are expressed at different times and in different locations. Moreover, all PbrATGs also responded to different abiotic stresses, especially salt and drought stress, which elicited the highest expression levels. Pear seedlings were subsequently infected with Botryosphaeria dothidea (B.dothidea). The results showed that different PbrATGs had different expression patterns at different infection stages. According to the gene expression data, PbrATG1a was selected as a key autophagy gene for further analysis. Silencing of PbrATG1a reduced the resistance of pear to B. dothidea, which resulted in increased lesions, reactive oxygen species (ROS) contents, antioxidant enzyme activity, and gene expression levels in the silenced pear seedlings after B. dothidea inoculation. In this study, a comprehensive bioinformatic analysis of ATGs was conducted, and the functions of PbrATGs in pear development and in response to stress were elucidated, which laid a foundation for further study of the molecular mechanism of autophagy and a new strategy for pear resistance breeding.

以金属有机骨架为源制备单原子电催化剂用于能量转换的最新进展

化石燃料的过度使用导致了严重的环境问题,因此,迫切需要人们对能源生产和储存方式进行变革.电催化在清洁能源转换中发挥着重要的作用,是推动可持续能源生产技术不断发展的重要驱动力.单原子催化剂(SACs)因具有独特的物理和化学性质而表现较高的电催化活性,因而成为研究热点.通过调控金属单原子的配位环境,可以有效调节SACs的几何和电子结构,进而优化电催化效率.金属有机骨架(MOFs)具有孔结构丰富、表面积大和配体可调节等结构特性,因此在制备SACs方面表现出巨大潜力.本文旨在总结以MOFs为前驱体制备SACs的最新进展,深入探讨单原子空间分布、配位结构和电子结构等局部配位环境对电催化活性的影响.此外,对密度泛函理论在研究SACs电催化反应中的应用进行了讨论和分析.本文系统地介绍了以MOFs为前驱体制备SACs的合成策略、表征方法、电催化应用和反应机理的研究进展,并对其未来的发展进行了展望.首先,概述了以MOFs为原料制备SACs的多种策略,分析了各自的优缺点及改进方向.然后,介绍了SACs的结构表征及电催化反应机理的原位表征技术,剖析了现有技术面临的挑战.再后,重点介绍了一些经典的制备SACs案例,对以MOFs为源制备的SACs在电催化析氢反应、析氧反应、氧还原反应、CO_(2)还原反应及氮还原消除等的应用进行了系统总结,并简要回顾了其在光催化、热催化、酶催化方向的应用.最后,探讨了SACs面临的挑战及解决方案:(1)目前采用的以MOFs为源制备SACs方法存在能耗高、污染环境等问题,应开发出环保可持续的合成方法以降低生产成本,并将其对环境的影响降到最低.(2)应利用原子水平控制技术制备双原子或三原子多功能电催化剂,并根据SACs的应用场景调整其配位结构,以优化性能.(3)需研发更先进的测试仪器,解决测试结果区域化、效率低、测试与实际结果存在偏差以及测试成本较高等问题.(4)基于SACs的结构特性,结合先进的测试仪器与理论计算,深入探究反应机理,为新一代电催化剂的设计提供指导.(5)随着信息技术的多维、多样和复杂化发展,可以借助机器学习,设计和开发新型SACs,推动电催化领域的持续创新.综上,本文系统地介绍了以MOFs为材料制备SACs的优势、设计原理、表征手段,并对SACs在电催化应用方面的研究进展与面临的挑战进行了总结,希望能为SACs相关方面的研究提供有价值的参考和借鉴.

A novel Effective Panicle Number per Plant 4 haplotype enhances grain yield by coordinating panicle number and grain number in rice

Increasing effective panicle number per plant(EPN)is one approach to increase yield potential in rice.However,molecular mechanisms underlying EPN remain unclear.In this study,we integrated mapbased cloning and genome-wide association analysis to identify the EPN4 gene,which is allelic to NARROW LEAF1(NAL1).Overexpression lines containing the Teqing allele(TQ)of EPN4 had significantly increased EPN.NIL-EPN4^(TQ) in japonica(geng)cultivar Lemont(LT)exhibited significantly improved EPN but decreased grain number and flag leaf size relative to LT.Haplotype analysis indicated that accessions with EPN4-1 had medium EPN,medium grain number,and medium grain weight,but had the highest grain yield among seven haplotypes,indicating that EPN4-1 is an elite haplotype of EPN4 for positive coordination of the three components of grain yield.Furthermore,accessions carrying the combination of EPN4-1 and haplotype GNP1-6 of GNP1 for grain number per panicle showed higher grain yield than those with other allele combinations.Therefore,pyramiding of EPN4-1 and GNP1-6 could be a preferred approach to obtain high yield potential in breeding.

Thermal management by manipulating electromagnetic parameters

Electromagnetic absorbing materials may convert electromagnetic energy into heat energy and dissipate it.However,in a high-power electromagnetic radiation environment,the temperature of the absorbing material rises significantly and even burns.It becomes critical to ensure electromagnetic absorption performance while minimizing temperature rise.Here,we systematically study the coupling mechanism between the electromagnetic field and the temperature field when the absorbing material is irradiated by electromagnetic waves.We find out the influence of the constitutive parameters of the absorbing materials(including uniform and non-uniform)on the temperature distribution.Finally,through a smart design,we achieve better absorption and lower temperature simultaneously.The accuracy of the model is affirmed as simulation results aligned with theoretical analysis.This work provides a new avenue to control the temperature distribution of absorbing materials.

The optimal atropine concentration for myopia control in Chinese children: a systematic review and network Metaanalysis

AIM:To figure out whether various atropine dosages may slow the progression of myopia in Chinese kids and teenagers and to determine the optimal atropine concentration for effectively slowing the progression of myopia.METHODS:A systematic search was conducted across the Cochrane Library,PubMed,Web of Science,EMBASE,CNKI,CBM,VIP,and Wanfang database,encompassing literature on slowing progression of myopia with varying atropine concentrations from database inception to January 17,2024.Data extraction and quality assessment were performed,and a network Meta-analysis was executed using Stata version 14.0 Software.Results were visually represented through graphs.RESULTS:Fourteen papers comprising 2475 cases were included;five different concentrations of atropine solution were used.The network Meta-analysis,along with the surface under the cumulative ranking curve(SUCRA),showed that 1%atropine(100%)>0.05%atropine(74.9%)>0.025%atropine(51.6%)>0.02%atropine(47.9%)>0.01%atropine(25.6%)>control in refraction change and 1%atropine(98.7%)>0.05%atropine(70.4%)>0.02%atropine(61.4%)>0.025%atropine(42%)>0.01%atropine(27.4%)>control in axial length(AL)change.CONCLUSION:In Chinese children and teenagers,the five various concentrations of atropine can reduce the progression of myopia.Although the network Meta-analysis showed that 1%atropine is the best one for controlling refraction and AL change,there is a high incidence of adverse effects with the use of 1%atropine.Therefore,we suggest that 0.05%atropine is optimal for Chinese children to slow myopia progression.

Millimeter-wave PA design techniques in ISSCC 2024

Millimeter-wave systems with high integration level have been rapidly developed to enable modern wireless communication,sensing,and imaging.The millimeter-wave power amplifier(PA)is one of the most challenging and critical components in a millimeter-wave transceiver,it is the last active stage in a transmitter amplifying spectrally efficient complex modulation signal for radiation with high output power.

荧光和羟基修饰聚天冬氨酸的制备与阻垢性能——推荐一个综合化学实验

设计了荧光和羟基修饰聚天冬氨酸的制备、表征和阻垢性能的综合实验。首先合成了水溶性荧光物质和聚琥珀酰亚胺(PSI),然后用该荧光物质和乙醇胺修饰PSI并碱性水解,获得目标阻垢剂。用1H NMR、凝胶渗透色谱和荧光分光光度计表征该阻垢剂,并通过静态阻垢试验测试该阻垢剂的阻垢性能。本实验融合了高分子化学、有机化学和分析化学内容,体现了“合成–表征–分析”的科学研究过程,强调了“物质–结构–性能”的科研思维模式,可以培养学生的实验素养和科研能力。

鸢尾素通过Nrf2/GPX4信号通路减轻脂多糖诱导的大鼠急性肺损伤的作用机制

目的探讨Nrf2/GPX4信号通路在鸢尾素减轻脂多糖(LPS)诱导的大鼠急性肺损伤中的作用。方法将72只健康雄性SD大鼠随机分为对照组(C组)、急性肺损伤组(ALI组)、鸢尾素组(Ir组)、鸢尾素+Nrf2抑制剂组(Ir+ML385组)。各组于模型制备后24 h收集支气管肺泡灌洗液(BALF),测定BALF中蛋白浓度,采用ELISA法检测BALF中IL-6、TNF-α含量;HE染色观察肺组织病理学结果并评分,计算肺组织湿/干重比;比色法检测肺组织中Fe^(2+)、MDA、GSH含量;Western blot测定肺组织中GPX4、ACSL4及胞核Nrf2的表达。结果与C组比较,ALI组中BALF蛋白浓度、IL-6、TNF-α含量、肺组织病理损伤评分、湿/干重比、Fe^(2+)、MDA含量均增加,GSH含量降低,GPX4表达降低,ACSL4、胞核Nrf2表达增加(P<0.05);与ALI组比较,Ir组中BALF蛋白浓度、IL-6、TNF-α含量、肺组织病理损伤评分、湿/干重比、Fe^(2+)、MDA含量均降低,GSH含量增加,GPX4、胞核Nrf2表达增加,ACSL4表达降低(P<0.05);与Ir组比较,Ir+ML385组中BALF蛋白、IL-6、TNF-α含量、肺组织病理损伤评分、湿/干重比、Fe^(2+)、MDA含量均增加,GSH含量降低,GPX4、胞核Nrf2表达降低,ACSL4表达增加(P<0.05)。结论Nrf2/GPX4信号通路参与了鸢尾素减轻LPS诱导的大鼠急性肺损伤的过程,其与抑制铁死亡有关。

Clinical and Pathological Research Status of Multiple Pulmonary Nodules

With the changes in disease spectrum and the popularization of screening of low-dose spiral CT (CT) in the chest, more and more pulmonary nodules have been detected, most of which are bipulmonary multiple nodules. The existence of multiple pulmonary nodules means that it may be a pathological state of benign and malignant co-existence. The origin and evolution of pulmonary nodules in different histopathological states have a great impact on the choice of treatment methods. In recent years, the rise of immunotherapy has brought a breakthrough in the treatment of refractory lung cancer. However, some patients are still ineffective in immunotherapy, which may be related to the immune microenvironment where nodules are proportioned in different components in different pathological states. This review article mainly predicts the development process of nodules by analyzing the origin of multiple pulmonary nodules and the immune microenvironment of nodules in different pathological conditions, so as to provide guidance for clinical treatment.

定量分析单眼视网膜静脉阻塞患者视盘区变化

目的:通过光学相干断层扫描血管成像技术(OCTA)定量分析单眼视网膜静脉阻塞(RVO)患者视盘旁放射状毛细管血流密度(ppVD)与视盘旁视网膜神经纤维层(pRNFL)厚度的变化及相关性。方法:前瞻性观察性研究。纳入2021-01/12于安徽理工大学第一附属医院眼科就诊的单眼RVO患者43例,其中RVO患眼43眼作为患侧组,未受累眼43眼作为对侧组,同时期选取年龄、性别与RVO患者相匹配的健康志愿者21例42眼作为对照组。采用OCTA测量视盘内血流密度(VD)、视盘周围VD及其上侧(pS)、下侧(pI)、颞侧上方(TS)、上方颞侧(ST)、上方鼻侧(SN)、鼻侧上方(NS)、鼻侧下方(NI)、下方鼻侧(IN)、下方颞侧(IT)、颞侧下方(TI)的ppVD与pRNFL厚度,分析纳入受检者ppVD和pRNFL厚度的特征性改变及相关性。结果:与对照组相比,患侧组视盘内VD、视盘周围整体VD及pS、pI、TI、ST、SN侧ppVD均下降,对侧组仅视盘内VD降低(均P<0.05)。与对照组相比,患侧组TS侧pRNFL厚度升高,对侧组ST和IT侧pRNFL厚度降低(均P<0.01)。典型相关性分析提示,ppVD与pRNFL厚度两组综合变量相关性较强,患侧组和对侧组有2对典型相关变量,对照组有3对典型相关变量。结论:单眼RVO患者患眼视盘区VD降低,对侧眼ST和IT侧pRNFL厚度变薄,ppVD与pRNFL厚度整体存在较强正相关性,视盘区整体ppVD与pRNFL厚度的改变多表现在患眼上侧象限和对侧眼下侧象限。

不同喷吹气体对铜冶炼熔渣中砷气化脱除的影响

为了减少铜熔炼渣中砷所带来的环境问题,提出一种基于气体喷吹脱除熔融铜渣中砷的方法,期望在铜回收工艺前将铜熔炼渣中的砷尽可能以粉尘的形式富集。对比惰性气体、氧化性气体和还原性气体对熔渣中砷脱除的影响。氧化性气体CO_(2)氧化夹杂冰铜中的砷及砷硫化物,并充当气体载体将砷氧化物带出熔池。还原性气体CO可以将FeOx-SiO_(2)熔渣中的砷氧化物还原,并使其挥发至气相,可以实现60%以上的砷脱除率。该研究为熔炼渣中砷脱除提供指导。

E2F家族转录因子在肿瘤发生中的作用

肿瘤严重威胁人类健康,转录因子是肿瘤治疗的潜在靶点。作为重要的转录因子家族,E2F在细胞增殖与调控进程中发挥重要作用。然而,E2F家族转录因子在肿瘤发生进程中的表达规律、基因功能和分子互作等关键信息尚不清晰。基于此,本研究对TCGA数据库中我国10种高发肿瘤的转录组测序数据、突变数据和蛋白质互作数据进行整合分析,探究E2F家族转录因子的表达、结构、功能、突变和系统发生特征。结果显示,E2F家族转录因子中的E2F1和E2F7基因在多种肿瘤样本中规律性上调表达,参与调控细胞周期、细胞衰老等信号通路;其中,E2F1作为重要的调控因子与其他蛋白的相互作用最多。值得指出的是,E2F家族转录因子的基因突变类型在肿瘤类型和患者性别中均存在差异,基因扩增占比最大。系统发生分析显示,E2F家族转录因子的结构在包括果蝇、线虫和人类在内41个物种中保守,并且它们在物种演化过程中表现出基因扩张倾向。综上所述,本研究阐明了E2F家族转录因子在我国高发肿瘤中的表达规律、突变特征和演化规律,提示E2F家族转录因子是相关肿瘤疾病的新型分子诊断标志物,为抗肿瘤靶向药物研发提供理论依据。

SD-OCT参数评估黄斑裂孔内界膜撕除术后视力改善的应用价值

目的:分析频域光学相干断层扫描(SD-OCT)参数评估黄斑裂孔内界膜撕除术后视力改善情况的应用价值。方法:回顾性分析2019-05/2021-02于我院行玻璃体切除+内界膜撕除+长效气体填充术治疗的特发性黄斑裂孔(IMH)患者82例82眼的临床资料,分析术后3mo IMH闭合情况与SD-OCT参数的相关性,并评估影响术后视力改善不良的危险因素。结果:Spearman秩相关分析显示,术后3mo IMH闭合情况与术前外界膜(ELM)缺损直径呈正相关(r_(s)=0.308,P<0.05),与术前黄斑裂孔指数(MHI)呈负相关(r_(s)=-0.266,P<0.05)。Logistic回归分析显示,术前MHI≥0.5是影响术后视力改善不良的保护因素(OR=0.691,P<0.05)。结论:SD-OCT可通过检测术前MHI及ELM缺损直径等参数预测手术疗效,对判断视功能改善情况有利。

Fe40Mn40Cr10Co10/TiC中熵合金复合材料的力学和摩擦磨损性能（英文）

采用机械球磨和放电等离子烧结方法制备Fe40Mn40Cr10Co10/TiC (TiC 的体积分数为10%)中熵合金复合材料,并对其力学和摩擦磨损性能进行研究。研究表明,在1373 K 烧结15 min 后,TiC 颗粒均匀分布在Fe40Mn40Cr10Co10/TiC 复合材料中,烧结后复合材料的晶粒得到明显细化;同时,添加10% TiC 颗粒使复合材料的抗压强度从1.571 GPa 提高至2.174 GPa ,维氏硬度从HV 320 提高至HV 872 。摩擦磨损试验表明,与Fe40Mn40Cr10Co10 中熵合金基体相比,复合材料的摩擦因数、磨痕深度和宽度都减小。良好的力学性能和摩擦磨损性能使Fe40Mn40Cr10Co10/TiC 复合材料成为工程应用的理想材料。

Calcitriol attenuates liver fibrosis through hepatitis C virus nonstructural protein 3-transactivated protein 1-mediated TGF β1/Smad3 and NF-κB signaling pathways

BACKGROUND Hepatic fibrosis is a serious condition,and the development of hepatic fibrosis can lead to a series of complications.However,the pathogenesis of hepatic fibrosis remains unclear,and effective therapy options are still lacking.Our group identified hepatitis C virus nonstructural protein 3-transactivated protein 1(NS3TP1) by suppressive subtractive hybridization and bioinformatics analysis,but its role in diseases including hepatic fibrosis remains undefined.Therefore,additional studies on the function of NS3TP1 in hepatic fibrosis are urgently needed to provide new targets for treatment.AIM To elucidate the mechanism of NS3TP1 in hepatic fibrosis and the regulatory effects of calcitriol on NS3TP1.METHODS Twenty-four male C57BL/6 mice were randomized and separated into three groups,comprising the normal,fibrosis,and calcitriol treatment groups,and liver fibrosis was modeled by carbon tetrachloride(CCl4).To evaluate the level of hepatic fibrosis in every group,serological and pathological examinations of the liver were conducted.TGF-β1 was administered to boost the in vitro cultivation of LX-2 cells.NS3TP1,α-smooth muscle actin(α-SMA),collagen I,and collagen Ⅲ in every group were examined using a Western blot and real-time quantitative polymerase chain reaction.The activity of the transforming growth factor beta 1(TGFβ1)/Smad3 and NF-κB signaling pathways in each group of cells transfected with pcDNA-NS3TP1 or siRNA-NS3TP1 was detected.The statistical analysis of the data was performed using the Student’s t test.RESULTS NS3TP1 promoted the activation,proliferation,and differentiation of hepatic stellate cells(HSCs)and enhanced hepatic fibrosis via the TGFβ1/Smad3 and NF-κB signaling pathways,as evidenced by the presence of α-SMA,collagen I,collagen Ⅲ,p-smad3,and p-p65 in LX-2 cells,which were upregulated after NS3TP1 overexpression and downregulated after NS3TP1 interference.The proliferation of HSCs was lowered after NS3TP1 interference and elevated after NS3TP1 overexpression,as shown by the luciferase assay.NS3TP1 inhibited the apoptosis of HSCs.Moreover,both Smad3 and p65 could bind to NS3TP1,and p65 increased the promoter activity of NS3TP1,while NS3TP1 increased the promoter activity of TGFβ1 receptor I,as indicated by coimmunoprecipitation and luciferase assay results.Both in vivo and in vitro,treatment with calcitriol dramatically reduced the expression of NS3TP1.Calcitriol therapy-controlled HSCs activation,proliferation,and differentiation and substantially suppressed CCl4-induced hepatic fibrosis in mice.Furthermore,calcitriol modulated the activities of the above signaling pathways via downregulation of NS3TP1.CONCLUSION Our results suggest that calcitriol may be employed as an adjuvant therapy for hepatic fibrosis and that NS3TP1 is a unique,prospective therapeutic target in hepatic fibrosis.

Poly(lactic acid)-aspirin microspheres prepared via the traditional and improved solvent evaporation methods and its application performances

Drug-loaded microspheres are significant for the development of modern pharmaceutical products. It is well known that the taken of aspirin for long-term increases the risk of serious gastrointestinal complications, therefore a controllable delivery of aspirin is of importance to lighten those side effects. In this work, poly(lactic acid)(PLA) was chosen as the carrier to prepare PLA-aspirin microspheres by using the traditional and the improved solvent evaporation methods. It was found that no matter which experimental condition was, the encapsulation efficiency of aspirin was higher by using the improved method than that of the traditional method. Specifically, when the concentration of polyvinyl alcohol = 1%(mass),the polymer concentration = 1:20, the oil/water rate = 1:2.5, PLA-aspirin microspheres were obtained via the improved method with a high yield of 82.83%(mass) and an encapsulation efficiency of 44.09%. PLAaspirin microspheres were then prepared continuously using the improved method, which further enhanced the encapsulation efficiency to 54.56%. Approximate 85% aspirin released from microspheres within 7 days. Obvious degradation which was represented by reduction on hardness was observed by soaking microspheres in PBS for 60 days. This work is of interest because it provides a continuous route to prepare PLA-aspirin microspheres continuously with a high drug encapsulation efficiency.

Evaluation of trabecular meshwork-specific promoters in vitro and in vivo using scAAV2 vectors expressing C3 transferase

AIM:To evaluate the potential of two trabecular meshwork(TM)-specific promoters,Chitinase 3-like 1(Ch3L1)and matrix gla protein(MGP),for improving specificity and safety in glaucoma gene therapy based on self-complementary AAV2(scAAV2)vector technologies.METHODS:An scAAV2 vector with C3 transferase(C3)as the reporter gene(scAAV2-C3)was selected.The scAAV2-C3 vectors were driven by Ch3L1(scAAV2-Ch3L1-C3),MGP(scAAV2-MGP-C3),enhanced MGP(scAAV2-eMGP-C3)and cytomegalovirus(scAAV2-CMV-C3),respectively.The cultured primary human TM cells were treated with each vector at different multiplicities of infections.Changes in cell morphology were observed by phase contrast microscopy.Actin stress fibers and Rho GTPases/Rho-associated protein kinase pathway-related molecules were assessed by immunofluorescence staining,real-time quantitative polymerase chain reaction and Western blot.Each vector was injected intracamerally into the one eye of each rat at low and high doses respectively.In vivo green fluorescence was visualized by a Micron III Retinal Imaging Microscope.Intraocular pressure(IOP)was monitored using a rebound tonometer.Ocular responses were evaluated by slit-lamp microscopy.Ocular histopathology analysis was examined by hematoxylin and eosin staining.RESULTS:In TM cell culture studies,the vectormediated C3 expression induced morphologic changes,disruption of actin cytoskeleton and reduction of fibronectin expression in TM cells by inhibiting the Rho GTPases/Rhoassociated protein kinase signaling pathway.At the same dose,these changes were significant in TM cells treated with scAAV2-CMV-C3 or scAAV2-Ch3L1-C3,but not in cells treated with scAAV2-eMGP-C3 or scAAV2-MGP-C3.At lowinjected dose,the IOP was significantly decreased in the scAAV2-Ch3L1-C3-injected eyes but not in scAAV2-MGPC3-injected and scAAV2-eMGP-C3-injected eyes.At highinjected dose,significant IOP reduction was observed in the scAAV2-eMGP-C3-injected eyes but not in scAAV2-MGP-C3-injected eyes.Similar to scAAV2-CMV-C3,scAAV2-Ch3L1-C3 vector showed efficient transduction both in the TM and corneal endothelium.In anterior segment tissues of scAAV2-eMGP-C3-injected eyes,no obvious morphological changes were found except for the TM.Inflammation was absent.CONCLUSION:In scAAV2-transduced TM cells,the promoter-driven efficiency of Ch3L1 is close to that of cytomegalovirus,but obviously higher than that of MGP.In the anterior chamber of rat eye,the transgene expression pattern of scAAV2 vector is presumably affected by MGP promoter,but not by Ch3L1 promoter.These findings would provide a useful reference for improvement of specificity and safety in glaucoma gene therapy using scAAV2 vector.