Intravitreal conbercept injection with panretinal photocoagulation for high-risk proliferative diabetic retinopathy with vitreous hemorrhage

AIM:To assess the clinical efficacy and safety of combining panretinal photocoagulation(PRP)with intravitreal conbercept(IVC)injections for patients with high-risk proliferative diabetic retinopathy(HR-PDR)complicated by mild or moderate vitreous hemorrhage(VH),with or without diabetic macular edema(DME).METHODS:Patients diagnosed with VH with/without DME secondary to HR-PDR and received PRP combined with IVC injections were recruited in this retrospective study.Upon establishing the patient’s diagnosis,an initial IVC was performed,followed by prompt administration of PRP.In cases who significant bleeding persisted and impeded the laser operation,IVC was sustained before supplementing with PRP.Following the completion of PRP,patients were meticulously monitored for a minimum of six months.Laser therapy and IVC injections were judiciously adjusted based on fundus fluorescein angiography(FFA)results.Therapeutic effect and the incidence of adverse events were observed.RESULTS:Out of 42 patients(74 eyes),29 were male and 13 were female,with a mean age of 59.17±12.74y(33-84y).The diabetic history was between 1wk and 26y,and the interval between the onset of visual symptoms and diagnosis of HR-PDR was 1wk-1y.The affected eye received 2.59±1.87(1-10)IVC injections and underwent 5.5±1.02(4-8)sessions of PRP.Of these,68 eyes received PRP following 1 IVC injection,5 eyes after 2 IVC injections,and 1 eye after 3 IVC injections.Complete absorption of VH was observed in all 74 eyes 5-50wk after initial treatment,with resolution of DME in 51 eyes 3-48wk after initial treatment.A newly developed epiretinal membrane was noted in one eye.Visual acuity significantly improved in 25 eyes.No complications such as glaucoma,retinal detachment,or endophthalmitis were reported.CONCLUSION:The study suggests that the combination of PRP with IVC injections is an effective and safe modality for treating diabetic VH in patients with HR-PDR.

1例精神分裂症伴妊娠合并糖尿病患者的药学监护

临床药师参与1例精神分裂症伴妊娠合并糖尿病患者的治疗过程,结合患者既往疾病史、用药史、家族史,分析可能导致患者血糖升高的药物性因素并进行用药教育和药学监护,提出合理化建议,取得了良好的治疗效果。通过本例药学监护,临床药师发挥药学专业优势,使患者得到更专业的医疗服务,并发挥了医患之间的桥梁作用,提升临床药师在医疗团队的地位。

我国生物医药领域中生物医学新技术发展及管理现状的思考

生物医药领域在不断发展的同时,对相关技术的需求也在不断提升。生物医学新技术是一类作用于细胞或分子水平的新兴的生物医学技术,是支撑生物医学发展的有力保障。作为一种新的试验性治疗方法,其收益和风险尚需足够的研究检验。我国生物医学新技术近年在相关政策支持下取得了巨大的成就,但该技术目前还存在定义模糊、风险监管缺失等问题。本文介绍了不同领域中生物医学新技术的定义,以生物医药领域中的生物医学新技术为对象,分析我国现有生物医学新技术市场发展和管理现状,以及相关生物技术伴随的风险,并对监管体系提出相应建议。

Oncogenic BRAF^(V600E) induces microglial proliferation through extracellular signal-regulated kinase and neuronal death through c-Jun N-terminal kinase

Activating V600E in v-Raf murine sarcoma viral oncogene homolog B(BRAF)is a common driver mutation in cancers of multiple tissue origins,including melanoma and glioma.BRAF^(V600E) has also been implicated in neurodegeneration.The present study aims to characterize BRAF^(V600E) during cell death and proliferation of three major cell types of the central nervous system:neurons,astrocytes,and microglia.Multiple primary cultures(primary cortical mixed culture)and cell lines of glial cells(BV2)and neurons(SH-SY5Y)were employed.BRAF^(V600E) and BRAF^(WT) expression was mediated by lentivirus or retrovirus.Blockage of downstream effectors(extracellular signal-regulated kinase 1/2 and JNK1/2)were achieved by siRNA.In astrocytes and microglia,BRAF^(V600E) induces cell proliferation,and the proliferative effect in microglia is mediated by activated extracellular signal-regulated kinase,but not c-Jun N-terminal kinase.Conditioned medium from BRAF^(V600E)-expressing microglia induced neuronal death.In neuronal cells,BRAF^(V600E) directly induces neuronal death,through c-Jun N-terminal kinase but not extracellular signal-regulated kinase.We further show that BRAF-related genes are enriched in pathways in patients with Parkinson’s disease.Our study identifies distinct consequences mediated by distinct downstream effectors in dividing glial cells and in neurons following the same BRAF mutational activation and a causal link between BRAF-activated microglia and neuronal cell death that does not require physical proximity.It provides insight into a possibly important role of BRAF in neurodegeneration as a result of either dysregulated BRAF in neurons or its impact on glial cells.

Effect of microwave-assisted acidification on the microstructure of coal:XRD,^(1)H-NMR, and SEM studies

Microwave heating contributes to coal fracturing and gas desorption. However, problems of low penetration depth, local overheating and fracture closure exist. Coal demineralisation by acids has advantages in coal unblocking and permeability improvement, while it is difficult for acid to enter microcracks.Microwave-asisted acidification may offer an alternative. In this work, XRD,^(1)H-NMR, and SEM were used to evaluate the effect of microwave-assisted acidification on the microstructure of coal. Results show that kaolinite, calcite, and dolomite can be dissolved by acid. After microwave irradiation, the graphitization of microcrystalline structure of carbon improves. Microwave-assisted acidification erodes minerals in coal and enhances the graphitization degree of microcrystalline structure. Compared to individual microwave irradiation or acidification, the pore volume and pore connectivity can be greatly enhanced by microwave-assisted acidification. The NMR permeability of coal increased by 28.05%. This study demonstrates the potential of microwave-assisted acidification for coalbed methane recovery.

Experimental research on influence mechanism of loading rates on rock pressure stimulated currents

The study of pressure stimulated current(PSC)changes of rocks is significant to monitor dynamic disasters in mines and rock masses.The existing studies focus on change laws and mechanism of currents generated under the loading of rocks.An electrical and mechanics test system was established in this paper to explore the impacts of loading rates on PSCs.The results indicated that PSC curves of different rocks had different change laws under low/high loading rates.When the loading rate was relatively low,PSC curves firstly changed gently and then increased exponentially.Under high loading rates,PSC curves experienced the rapid increase stage,gentle increase stage and sudden change stage.The compressive strength could greatly affect the peak PSC in case of rock failure.The loading rate was a key factor in average PSC.Under low loading rates,the variations of PSCs conformed to the damage charge model of fracture mechanics,while they did not at the fracture moment.Under high loading rates,the PSCs at low stress didn’t fit the model due to the stress impact effects.The experimental results could provide theoretical basis for the influence of loading rates on PSCs.

A nonparametric spectrum estimation method for dispersion and attenuation analysis of borehole acoustic measurements

Dispersion and attenuation analysis can be used to determine formation anisotropy induced by fractures,or stresses.In this paper,we propose a nonparametric spectrum estimation method to get phase dispersion characteristics and attenuation coefficient.By designing an appropriate vector filter,phase velocity,attenuation coefficient and amplitude can be inverted from the waveform recorded by the receiver array.Performance analysis of this algorithm is compared with Extended Prony Method(EPM)and Forward and Backward Matrix Pencil(FBMP)method.Based on the analysis results,the proposed method is capable of achieving high resolution and precision as the parametric spectrum estimation methods.At the meantime,it also keeps high stability as the other nonparametric spectrum estimation methods.At last,applications to synthetic waveforms modeled using finite difference method and real data show its efficiency.The real data processing results show that the P-wave attenuation log is more sensitive to oil formation compared to S-wave;and the S-wave attenuation log is more sensitive to shale formation compared to P-wave.

Economic and entropy production evaluation of extractive distillation and solvent-assisted pressure-swing distillation by multi-objective optimization

Extractive distillation(ED)and solvent-assisted pressure-swing distillation(SA-PSD)are both special distillation processes that perform good at separating pressure-insensitive azeotropes.However,few reported studies have compared the performance of the two processes.In this paper,ED processes with N-methylpyrrolidone(NMP)and dimethlac-etamide(DMCA)as entrainer,SA-PSD process with isopropyl-alcohol(IPA)as solvent and SA-PSD process with partial heat integration(PHI-PSD)are proposed to achieve high purity separation of a mixture of cyclohexane/2-butanol system.The optimal operating conditions of the processes are obtained after optimizing with NSGA-Ⅱ algorithm when total annual cost(TAC)and the entropy production of process are set as objectives.The optimal results show that the optimal PHI-PSD process has lower TAC by 28.7% and the lower entropy production by 39.5% than the optimal SA-PSD process while the ED process with NMP as entrainer has lower TAC by 50.9% and the lower entropy production by 56.1% than the optimal SA-PSD process.The optimal results show that the ED process with NMP as entrainer has the best economic and thermodynamic efficiency among the four proposed processes in this paper.

Investigation of energy-efficient heat pump assisted heterogeneous azeotropic distillation for separating of acetonitrile/ethyl acetate/n-hexane mixture

The conventional distillation is hard to accomplish the separation of acetonitrile/ethyl acetate/n-hexane mixture. Herein, a heterogeneous azeotropic distillation(HAD) without adding entrainer is proposed to separate ternary mixture. The proposed scheme is optimized via the simulated annealing algorithm and minimum total annual cost(TAC) is used as objective functions. To minimize energy consumption,heat pump is added on the basis of optimal heterogeneous azeotropic distillation and heat integration technology is used to further improve the energy recovery. The TAC, gas emission, energy consumption and exergy destruction are used to discuss the economy and environmental protection of processes.Among all the processes, the heat pump with higher preheating temperature(HPT) assisted HAD process by combining with heat integration(HAD-HPT-HI) has best performances on economic, environment,energy and exergy. Compared with conventional HAD process, the HAD-HPT-HI achieves the reductions of 52.17%, 68.86%, 65.87% and 65.46% on TAC, total energy consumption, gas emissions and exergy destruction, respectively.

Treatment of corneal dermoid with lenticules from small incision lenticule extraction surgery:a surgery assisted by fibrin glue

AIM:To observe the clinical efficacy of the combined use of small incision lenticule extraction(SMILE)-derived lenticule patches in corneal dermoid excision,with fixation of the lenticule patches assisted by fibrin glue.METHODS:Seventeen eyes of 17 patients with corneal dermoid were treated with dermoid removal combined with SMILE-derived lenticule transplantation.All lenticule patches were fixed by fibrin glue.Ocular changes were assessed using slit lamp microscopy and anterior-segmental optical coherence tomography.The best-corrected visual acuity(BCVA)and ocular dioptric variations were examined preoperatively and postoperatively.Intraocular pressure(IOP)was also monitored in all visited time.RESULTS:Totally,18 lenticule patches were used on 17 eyes of 17 cornea dermoid patients.The mean follow-up time was 11.47±5.28mo.All lenticule patches we resuccessfullyg lued,kept on its location and maintained transparent during the follow-up time,with a consecutive epithelial cover for 1wk.Nine of the patients could coordinate visual and optometry exam well.Their preoperative BCVA is 0.60±0.35 in decimal,significantly improved to 0.80±0.26 in decimal at 6mo postoperatively(Z=-2.392,P=0.017),but the changes of their corneal astigmatism diopters showed no significance,with 2.22±1.91 D preoperatively,and 2.28±1.31 D at 6mo postoperatively(Z=-0.135,P=0.893).Limbal pannus formation occurred in 4(23.52%)cases and decreased with the application of tacrolimus eyedrops.IOP increased in 2(11.76%)cases,but well decreased by timolol maleate eyedrops.All the adult patients or guardians of minor patients were satisfied with the cosmetic improvement.CONCLUSION:Dermoid excision combined with transplantation of SMILE-derived lenticule patches using fibrin glue is a safe and effective novel tectonic keratoplasty procedure for corneal dermoid.

老年非酒精性脂肪性肝病的营养状况及能量代谢特点

背景随着全球人口老龄化和非酒精性脂肪性肝病(nonalcoholic fatty liver disease,NAFLD)增长,老年NAFLD人群特点的研究尤为重要.目的观察老年NAFLD患者的营养状态和能量代谢特点.方法回顾性分析2017-01/2019-01天津市第三中心医院消化科就诊的NAFLD老年患者118例,进行人体成分分析仪分析及应用代谢车评估营养及能量代谢指标,与老年非脂肪肝组进行比较.统计分析中正态分布计量资料采用独立样本t检验,非正态分布计量资料采用Mann-Whitney U检验,二元Logistic回归分析老年NAFLD发生的危险因素.结果人体成分分析显示老年NAFLD组腰臀脂肪比、体脂肪含量较老年非脂肪肝组明显增加(腰臀脂肪比0.95 vs 0.92,体脂肪27.20 kg vs 19.60 kg,P<0.005);代谢车测定结果显示老年NAFLD组静息能量消耗均高于老年非脂肪肝组(1769.00 kcal/d vs 1323.00 kcal/d,P<0.05);进一步比较老年NAFLD患者轻度脂肪肝组与中重度脂肪肝组,轻度脂肪肝组体脂肪、腰臀脂肪比、基础代谢、静息能量消耗明显低于中重度脂肪肝患者.结论在老年NAFLD患者中存在营养失衡和能量代谢紊乱,随脂肪肝程度加重更为显著,通过人体成分分析仪和代谢车以综合评价和监测老年NAFLD患者的营养及能量代谢状态,为疾病干预治疗提供依据.

L3-PMI在乙肝肝硬化相关慢加急性肝衰竭患者预后评估中的作用

背景肌肉减少症是终末期肝病患者死亡的独立危险因素,与患者的预后密切相关,因此受到广泛关注.但对于肌少症来说,目前还缺乏统一的检测方法和诊断标准,临床应用受限.目的评估乙肝肝硬化相关慢加急性肝衰竭(acute-on-chronic liver failure,ACLF)患者的第三腰椎腰大肌指数(the third lumbar level psoas muscle index,L3-PMI)与临床指标的关系及其在预后评估中的作用.方法采用回顾性研究的方法,选取2014-01/2017-12在天津市第三中心医院肝内科住院的符合乙肝肝硬化相关ACLF诊断标准且有腹部CT扫描资料的140例患者为研究对象.由同一名研究者在患者腹部CT图像上手动追踪第三腰椎下缘水平面,测量双侧腰大肌最大前后径和横径,计算腰大肌指数.分析患者的L3-PMI和临床特点及预后.结果将140例患者按90天生存情况分为生存组102例,死亡组38例.死亡组患者L3-PMI值4.89 cm^(2)/m^(2)±1.42 cm^(2)/m^(2)较生存组患者5.94 cm^(2)/m^(2)±1.24 cm^(2)/m^(2)显著降低(P<0.001);血小板(platelet,PLT)、白蛋白(albumin,ALB)、丙氨酸转移酶(alanine aminotransferase,ALT)、天门冬氨酸转移酶(aspartate transaminase,AST)、血肌酐(serum creatinine,SCr)、估算肾小球滤过率(estimated glomerular filtration rate,eGFR)在两组之间无统计学差异,P值均>0.05;死亡组患者白细胞(white blood cell,WBC)、国际标准化比值(international normalized ratio,INR)水平、终末期肝病模型(model for end-stage liver disease,MELD)评分显著高于生存组,而血清钠显著低于生存组(P值均<0.05).此外,ACLF患者中33例合并肝性脑病(hepatic encephalopathy,HE)的患者L3-PMI值5.17 cm^(2)/m^(2)±1.49 cm^(2)/m^(2)显著低于107例未合并HE的患者5.80 cm^(2)/m^(2)±1.29 cm^(2)/m^(2),(P=0.02).所有ACLF患者中男性120例,女性20例,其中男性组L3-PMI值5.92 cm^(2)/m^(2)±1.23 cm^(2)/m^(2)显著高于女性组4.03 cm^(2)/m^(2)±0.92 cm^(2)/m^(2),(P<0.05).按性别分别绘制L3-PMI预测死亡的ROC曲线图,其中男性ROC曲线下面积0.726,截断值为5.02,敏感度为85%,特异度50%;女性ROC曲线下面积0.774,截断值为4.60,敏感度为50%,特异度100%.结论L3-PMI对于评估乙肝肝硬化相关ACLF患者的预后有重要临床应用价值.

养猪废水中磺胺嘧啶对湿地底泥中氮转化微生物及过程影响

为探讨养殖废水中兽用抗生素对湿地系统中氮素转化及相关微生物过程的影响,以养殖废水中常见的抗生素SD(磺胺嘧啶)为例,设置0、10、100和1000μg L 4个添加浓度开展模拟试验.通过qPCR(实时荧光定量PCR)技术,测定了湿地底泥中氨氧化和反硝化功能基因丰度,结合Pearson相关分析,分析了养殖废水中不同氮素形态与底泥中氮转化功能基因丰度的关联性.结果表明:①与CK组比较,添加SD对湿地TN的最终去除效果无显著性差异,4个处理组的TN去除率为75.4%~80.5%,但在培养前期(0~14 d),SD对水体NH _(4)^(+)-N和NO_(3)^(-)-N转化的抑制率最高分别达53.0%和99.5%,随着SD浓度的增加,抑制作用越强,到培养后期(14~28 d),各处理水体中不同形态的氮浓度无显著差异.②由qPCR测试结果得出,湿地底泥中AOA(氨氧化古菌)的丰度比AOB(氨氧化细菌)高出1~2个数量级,表明AOA在氨氧化过程中起主导作用,另外在培养第7天,AOB发生显著抑制现象,对SD更敏感;与CK相比,在第7天和第14天,反硝化基因narG、nirS、nirK和nosZ丰度随SD浓度的增加而逐渐降低.③相关性分析结果表明,AOA与ρ(NH _(4)^(+)-N)呈极显著正相关(P<0.01),AOB与ρ(NO_(3)^(-)-N)呈极显著正相关(P<0.01),nirK与ρ(NO _(2)^(-)-N)呈极显著正相关(P<0.01).研究显示,SD能抑制湿地底泥中氮转化微生物及相关氮转化过程,且SD浓度越大,抑制作用也越大,但随着培养时间的增加抑制作用会减弱.

钠化海泡石负载过渡金属催化剂TM/NaSep(TM=Cu,Fe,Ni,Mn,Co)催化氧化甲醛性能

甲醛(HCHO)是一种典型的挥发性有机化合物(VOCs).空气中的甲醛主要来源于建筑材料、塑料、水泥和油漆等,长时间暴露于含有甲醛的空气中会对人体健康造成严重危害.因此,消除空气中的甲醛是亟待解决的问题.催化氧化是目前较好的去除甲醛的技术方法之一,它能有效地在较低温度下将甲醛氧化成CO2和H2O.通常,负载型贵金属(Au, Pt, Pd和Ag)催化剂具有较好的催化氧化甲醛性能,但高成本和易中毒的特性限制了其应用.负载型过渡金属催化剂具有成本低和催化氧化性能良好等特点,是当前研究的热点.而催化剂活性通常与所用载体及其物理性质相关,如晶体结构、化学组成、表面积和热稳定性等.因此,开发合适的载体,提高过渡金属催化剂的催化性能具有重要意义.海泡石是具有特定官能团和纤维状结构的天然粘土矿物,相比其他类型的硅酸盐粘土,其具有较高的吸附性能和较好的水热稳定性.本文通过浸渍法制备了钠化海泡石(Na Sep)负载过渡金属催化剂TM/Na Sep (TM=Cu, Fe, Ni, Mn, Co),研究了其物理化学性质,考察了其催化氧化甲醛(0.2%)性能.XRD与SEM结果表明,负载过渡金属不影响海泡石原矿的物理结构.H2-TPR, NH3-TPD和XPS结果表明,负载过渡金属对催化剂氧化还原性能、酸性和吸附氧能力影响较大.TM/NaSep总酸度与吸附氧能力(Oads/(Olatt+OOH))按以下顺序递减:Cu/Na Sep>Fe/NaSep>Mn/NaSep>Ni/NaSep>Co/NaSep.这与催化剂催化氧化甲醛活性顺序一致.在所有样品中,Cu/NaSep表现出最佳的催化氧化甲醛活性,在100°C (GHSV=240000 m L/(g·h))可以完全氧化甲醛.42 h稳定性测试表明其具有良好的稳定性.综合研究表明, Cu/NaSep催化剂优良的催化活性与其良好的低温还原性、较高的酸度和吸附氧能力等因素有关.原位DRIFTS研究Cu/NaSep催化剂催化氧化甲醛机理表明,首先,甲醛吸附在催化剂表面,然后表面的吸附氧物种将其氧化成亚甲二氧基(DOM)并迅速转化为甲酸盐物种.同时, Cu/NaSep催化剂较高的催化氧化性能还与海泡石载体的羟基与吸附氧的协同作用有关,海泡石的羟基可以促进甲醛在样品表面吸附,有利于甲酸盐形成,甲酸盐再进一步氧化生成碳酸盐,最终氧化生成CO2和H2O.

右美托咪定联合帕瑞昔布钠对鼻内镜手术苏醒期躁动及术后早期镇痛的影响

目的探讨帕瑞昔布钠联合右美托咪定(DEX)对鼻内镜手术苏醒期躁动的影响。方法选择2020年1月-2021年2月该院择期行全身麻醉下鼻内镜手术的患者104例。采用随机数表法分为实验组(DEX+帕瑞昔布钠组,DP组)和对照组(DEX,D组),各52例。两组患者麻醉诱导前,分别给予静脉输注DEX 0.5μg/kg,输注10 min,然后持续泵注0.4μg/(kg·h),手术结束前30 min停药。DP组DEX停药后立即给予帕瑞昔布钠40 mg静注。采用Ricker镇静-躁动评分(RSAS)评估两组患者拔管时及拔管后5 min躁动评分,视觉模拟评分法(VAS)评估患者术后2、4、8、12和24 h疼痛情况。比较两组患者苏醒期RSAS评分、术后VAS评分、恶心呕吐、鼻出血和胃肠道不适的发生率。结果与D组比较,DP组苏醒期RSAS明显降低[(3.6±0.7)和(4.0±0.8)分,(3.8±0.4)和(4.0±0.2)分,P<0.05],术后2、4和8 h VAS明显降低(P<0.05)。两组患者术后恶心、呕吐、鼻出血和胃肠道不适等并发症发生率比较,差异均无统计学意义(P>0.05)。结论帕瑞昔布钠联合DEX用于鼻内镜手术可以降低苏醒期RSAS评分,在术后早期具有良好的镇痛效果。

直接抗病毒药物治疗慢性丙型肝炎48周临床观察

背景慢性丙型肝炎(chronic hepatitis C,CHC)是全球公共卫生问题,随着直接抗病毒药(direct antiviral therapy,DAA)在中国的应用,DAA药物成为目前国内慢性丙型肝炎抗病毒一线方案,但目前真实世界DAA治疗后长期疗效数据尚少.目的观察慢性丙型肝炎患者接受直接抗病毒药物抗病毒治疗后48 wk病毒学应答及临床疗效.方法连续收集2018-04-01/2020-04-30在天津市第三中心医院接受DAA治疗的初治CHC患者,评估治疗基线、治疗结束、治疗后12 wk及48 wk的病毒学应答及肝肾功能、肝硬度、APRI及临床结局.结果共收集291例应用DAA治疗的CHC患者,纳入145例完成抗病毒治疗及随访的CHC患者进入本研究.其中肝硬化患者占28.3%,基因型1b、2a、3a、6a分别占78.0%、17.2%、2.8%、2.0%.DAA治疗结束、治疗后12 wk及48 wk获得持续病毒学应答(sustained virological response,SVR)比例分别为100%、97.9%和97.2%,其中基因型1b、2a、3a、6a的SVR48分别为97.3%、96%、100%、100%.治疗结束后48 wk与基线相比较,丙氨酸氨基转移酶、天冬氨酸氨基转移酶、总胆红素及白蛋白的复常率分别为93.2%、91.7%、73.3%及97.7%.治疗结束后48 wk肝硬度(liver stiffness measurement,LSM)及APRI与基线水平相比均明显下降(LSM 12.5 vs 10.2kpa P<0.01;APRI 0.34 vs 0.13 P<0.01),肝硬化组及非肝硬化组患者均有明显下降(P<0.05).48 wk随访期间,其中4例(2.8%)CHC患者进展为肝硬化,8例(5.6%)肝硬化患者进展为肝硬化失代偿,3例(2.1%)肝硬化患者发生新发肝细胞癌(hepatocellular carcinoma,HCC).结论本研究真实世界中慢性丙型肝炎患者应用DAA治疗后48 wk,总体病毒持续应答率较高,肝功能、肝硬度及APRI值均明显改善.2.1%患者出现新发HCC.

双酚二炔丙醚/氰酸酯共混树脂的制备与性能

合成了双酚A二炔丙醚(BADPE)和双酚E二炔丙醚(BEDPE)2种炔丙醚,分别与双酚A型氰酸酯树脂(BADCy)和双酚E型氰酸酯(BEDCy)共混制备了4种改性氰酸酯树脂。对改性氰酸酯的固化反应、热性能及力学性能进行了研究。结果表明,双酚二炔丙醚(BPDPE)可催化氰酸酯的固化反应,降低固化反应温度和反应活化能,加入中性镍催化剂可显著降低共混树脂的起始固化温度(T_(i)),200℃时可实现共混树脂的固化。BPDPE改性氰酸酯树脂固化物在氮气中5%热失重(T_(d5))温度在370℃以上,800℃残留率(Y_(r800℃))可达40%以上,在空气中的T_(d5)保持在380℃以上、极限氧指数(LOI)高于34%。BPDPE改性氰酸酯树脂的玻璃化转变温度(T_(g))高于200℃。BPDPE改性BEDCy树脂催化固化的浇铸体弯曲强度达129.4 MPa、弯曲模量达4.3 GPa、冲击强度达27.3 kJ/m^(2)。

Smile来源的角膜基质透镜构建组织工程角膜基质支架的实验研究

目的:探究用全飞秒激光小切口微透镜摘除术(Smile)来源的角膜基质透镜构建组织工程角膜基质支架的可行性及最佳保存条件。方法:从Smile来源的角膜基质透镜中分离培养人角膜基质细胞(HCFs),采用MTT法检测人纤维蛋白粘合剂(FS)对细胞的毒性作用;将FS粘贴双层角膜基质透镜构建的双层透镜支架分别置于不同介质(无水甘油、透明质酸钠、胎牛血清、模拟湿房环境)及不同温度(常温、4℃、-20℃)中保存,对比支架透明度及硬度。结果:MTT检测结果显示,FS作用0~72h,HCFs与正常培养细胞具有相似的增殖趋势,细胞毒性评级为0~1级,相对生存率均超过90%。FS粘贴的双层基质透镜支架表面平整、贴合紧密、透明度良好且硬度适宜。4℃保存14d后,无水甘油中9枚支架复水后均未出现开裂情况,透明度良好;透明质酸钠中9枚支架中3枚出现开裂,剩余6枚完整,透明度尚可;模拟湿房环境中9枚支架均无开裂现象,但皱缩严重;胎牛血清中9枚支架全部开裂,水肿严重。保存14d后,常温无水甘油中的15枚支架其中2枚保持无色透明,5枚轻微变黄但透明度尚可,8枚严重变黄且透明度明显降低;4℃无水甘油中的15枚支架其中5枚无色透明,10枚轻微变黄且透明度良好;-20℃无水甘油中的15枚支架均保持无色透明状态,未出现变黄情况。结论:FS是一种安全无毒的生物胶,可利用FS粘贴Smile来源的角膜基质透镜构建稳定性好、透明度高且硬度适宜的角膜基质支架,且-20℃无水甘油是角膜基质透镜支架的较佳保存条件。

大型发电机多胶模压定子线棒绝缘材料与结构机械性能试验方法分析

本文主要分析了大型发电机定子线棒多胶模压绝缘材料和绝缘结构的机械性能评定标准和方法。对多胶云母带和云母板材的机械性能指标进行简要分析,总结国内外定子线棒绝缘结构机械性能的评定方法。重点论述多胶模压绝缘结构热机械应力和电机械应力试验方法,介绍了多胶模压绝缘结构冷热循环试验、三点弯曲试验、冲击试验、疲劳试验、四点弯曲动态疲劳试验的方法和结果。本文为定子线棒及绝缘材料机械性能评定与优化、机械性能试验标准编制提供了重要的参考依据。

Anti-apoptotic effect of Shudipingchan granule in the substantia nigra of rat models of Parkinson＇s disease

Levodopa is the gold-standard treatment for Parkinson＇s disease. However, although it alleviates the clinical symptoms, it cannot delay the progressive apoptosis of dopaminergic neurons or prevent motor complications in the long term. In the present study, we investigated the effect of Shudipingchan granule on neuronal apoptosis in a rat model of Parkinson＇s disease, established by injecting 6-hydroxydopamine into the substantia nigra pars compacta and ventral tegmental area. We then administered levodopa （20 mg/kg intraperitoneally, twice daily） with or without Shudipingchan granule （7.5 mL/kg intragastrically, twice daily）, for 4 weeks. The long-term use of levodopa accel- erated apoptosis of nigral cells and worsened behavioral symptoms by activating the extracellular signal-regulated kinase pathway and downstream apoptotic factors. However, administration of Shudipingchan granule with levodopa reduced expression of phosphorylated extracellular signal-regulated kinase 1/2 and Bax, increased tyrosine hydroxylase and Bcl-2, reduced apoptosis in the substantia nigra, and markedly improved dyskinesia. These findings suggest that Shudipingchan granule suppresses neuronal apoptosis by inhibiting the hyper- phosphorylation of extracellular signal-regulated kinase and downregulating expression of anti-apoptotic genes. Shudipingchan granule, used in combination with levodopa, can effectively reduce the symptoms of Parkinson＇s disease.