A new promising nucleating agent for polymer foaming: effects of hollow molecular-sieve particles on polypropylene supercritical CO2 microcellular foaming

Because polypropylene (PP) foam normally exhibits nonuniform cell size and cracked cellular structure, a narrow cell-size distribution and a well-defined morphology are always the focus of PP foaming technology. In this work, hollow molecular-sieve (MS) particles were applied as a potential nucleating agent in supercritical carbon dioxide (scCO₂) foaming of PP. It was observed that the addition of MS particles largely narrowed the cell-size distribution. The resultant PP/MS foams exhibited significant concurrent enhancement in their cell density and mechanical properties: the cell density increased remarkably, by approximately 10 times, and the tensile strength increased from 6.1 MPa to 12.6 MPa. The hollow-structure MS particles resulted in a higher heterogeneous nucleation efficiency in the PP foaming process. We believe that the trapping of CO₂ in the hollow holes of MS particles largely increased the solubility CO₂ in PP and a number of gas cavities were formed. The existence of gas cavities reduced the energy barrier of heterogeneous nucleation, favoring the formation of a well-defined cellular structure. Additionally, the regular-hexagon shape of the cells might endow the PP foam with better mechanical properties compared with a circular cell shape.

Hollow molecular-sieve particles were applied as a new nucleating agent in preparing PP foam with outstanding mechanical properties by using scCO₂.     

超声造影参数预测高强度聚焦超声治疗局限型子宫腺肌病的临床价值

目的探讨超声造影(CEUS)参数预测局限型子宫腺肌病高强度聚焦超声(HIFU)治疗价值。方法对38例局限型子宫腺肌病患者在HIFU治疗前、治疗后进行CEUS检查,分析到达时间(AT)、达峰时间(TTP)、增强时间(ET)、达峰强度(PI)、曲线下面积(AUC),增强均匀度,并计算△PI=病灶区PI-参考区PI。术后根据消融率分为消融率≥60%组和<60%组,分析造影参数与消融率的关系。结果在消融率≥60%组和<60%组间病灶的AT、TTP、ET、PI、△PI、AUC、增强均匀度差异均有统计学意义(P<0.05)。AT、TTP、ET与消融率呈正相关(r=0.563,0.771,0.710,P<0.05),PI、△PI、AUC与消融率呈负相关(r=-0.489,-0.796,-0.697,P<0.05),增强均匀度与消融率弱相关。结论CEUS的参数AT、TTP、ET、PI、△PI、AUC与局限型子宫腺肌病高强度聚焦治疗消融率均有一定的相关性,在预测疗效中有一定的临床应用价值。     

Post-translational modifications: Regulators of neurodegenerative proteinopathies

One of the hallmark features in the neurodegenerative disorders (NDDs) is the accumulation of aggregated and/or non-functional protein in the cellular milieu. Post-translational modifications (PTMs) are an essential regulator of non-functional protein aggregation in the pathogenesis of NDDs. Any alteration in the post-translational mechanism and the protein quality control system, for instance, molecular chaperone, ubiquitin-proteasome system, autophagy-lysosomal degradation pathway, enhances the accumulation of misfolded protein, which causes neuronal dysfunction. Post-translational modification plays many roles in protein turnover rate, accumulation of aggregate and can also help in the degradation of disease-causing toxic metabolites. PTMs such as acetylation, glycosylation, phosphorylation, ubiquitination, palmitoylation, SUMOylation, nitration, oxidation, and many others regulate protein homeostasis, which includes protein structure, functions and aggregation propensity. Different studies demonstrated the involvement of PTMs in the regulation of signaling cascades such as PI3K/Akt/GSK3β, MAPK cascade, AMPK pathway, and Wnt signaling pathway in the pathogenesis of NDDs. Further, mounting evidence suggests that targeting different PTMs with small chemical molecules, which acts as an inhibitor or activator, reverse misfolded protein accumulation and thus enhances the neuroprotection. Herein, we briefly discuss the protein aggregation and various domain structures of different proteins involved in the NDDs, indicating critical amino acid residues where PTMs occur. We also describe the implementation and involvement of various PTMs on signaling cascade and cellular processes in NDDs. Lastly, we implement our current understanding of the therapeutic importance of PTMs in neurodegeneration, along with emerging techniques targeting various PTMs.     

上海市普陀区小学教师儿童牙外伤知识知晓度抽样调查

目的: 了解上海市普陀区小学教师对牙外伤相关知识的掌握情况。方法: 采用问卷答题方式,调查普陀区1 020名小学教师对儿童牙外伤处理相关知识的掌握程度,采用SPSS 20.0软件包对数据进行统计学分析。结果: 共回收有效问卷973份。74.8%教师知道就近处理牙外伤医疗机构的信息,53.8%的教师在学生发生牙外伤时会首先告知家长,59.1%的教师选择将折裂牙断片交由家长处理。79.5%的教师知道四年级学生的“门牙”是恒牙;对于脱落门牙的保存介质,12.7%的参与调查者选择了错误答案;62.7%的教师对于污染脱落牙的清洁方式回答正确;关于牙再植最佳时机,19.6%的教师回答正确。教师性别、年龄及是否接受过培训影响场景模拟题的得分（P<0.05）,学历不是最主要的影响因素（P>0.05）。结论: 普陀区小学教师尚未全面掌握儿童牙外伤的应急处理知识,医疗机构和教育机构需加强相关知识培训。     

带状疱疹后神经痛患者应用星状神经节阻滞联合选择性神经根阻滞的疗效观察及对其睡眠质量的影响

目的:观察星状神经节阻滞(Stellate Ganglion Block,SGB)联合选择性神经根阻滞治疗对带状疱疹后神经痛(Post-herpetic Neuralgia,PHN)患者的疗效及睡眠质量的影响。方法:选取2018年9月至2020年7月上海市嘉定区中医医院收治的PHN患者95例作为研究对象,按照随机数字表法将其随机分为观察组(n=47)和对照组(n=48)。2组患者均给予营养神经、口服止痛药等常规药物治疗,对照组患者在此基础上行选择性神经根阻滞术;观察组在对照组的基础上给予SGB。观察2组患者治疗前后视觉模拟评分(Visual Analogue Scale,VAS)、焦虑自评量表评分(Self-Rating Anxiety Scale,SAS)、抑郁自评量表评分(Self-rating Depression Scale,SDS)、睡眠质量评分(Self-Rating Scale of Sleep,SRSS)和治疗疗效。结果:观察组患者治疗总有效率为95.74%,显著高于对照组83.33%(P<0.05)。治疗前,2组患者的VAS、SAS及SDS评分比较差异无统计学意义(P>0.05);治疗后,观察组患者的VAS、SAS及SDS评分显著低于对照组(P<0.05);观察组患者SRSS评分显著低于对照组(t=3.734,P<0.05)。结论:星状神经节阻滞联合选择性神经根阻滞治疗可有效缓解PHN疼痛和不良情绪,提高PHN患者生命质量和睡眠质量,治疗效果好,值得临床推广运用。     

上海市1296名3~5岁儿童龋病及其相关危险因素分析

目的 了解上海市3~5岁儿童低龄儿童龋患病情况及相关危险因素,为龋病防治提供参考。方法 根据第4次全国口腔健康流行病学调查要求,采用多阶段分层、等容量随机抽样方法,抽取上海市1 296名4个区、12个幼儿园中3~5岁儿童进行龋病检查,对其家长进行口腔健康知识问卷调查。采用SPSS 21.0软件包进行统计学分析。结果 上海市3~5岁儿童的乳牙患龋率、龋均分别为58.07%、2.99,各年龄组及性别间差异均有统计学意义(P<0.05)。龋病相关单因素分析及多因素Logistics回归分析均显示,饮用甜饮料频率高、睡前吃甜食、刷牙频率少于每天1次、开始刷牙年龄大于2岁、家长受教育程度低及口腔健康知识水平差是患龋的危险因素。结论 上海市3~5岁儿童乳牙患龋率较高,加强儿童的饮食习惯及口腔卫生行为教育,提高家长口腔健康知识水平,是防治儿童龋病的有效途径。     

穴位按摩联合心脏康复操在冠状动脉支架植入患者中的应用效果

目的 探讨穴位按摩联合心脏康复操对冠状动脉支架植入术（PCI）患者血脂水平、心功能、情绪状态、睡眠及生活质量的影响。 方法 选择我院2017年1月～2019年12月收治的冠心病PCI患者120例,采用随机数字法将其分为对照组和干预组（每组60例）。对照组PCI术后采取常规运动康复治疗,干预组在常规运动康复治疗基础上,采取穴位按摩联合心脏康复操治疗。比较两组治疗前后血脂指标[总胆固醇（TC）、三酰甘油（TG）、低密度脂蛋白胆固醇（LDL-C）、高密度脂蛋白胆固醇（HDL-C）]、心功能指标[左室射血分数（LVEF）、氨基末端脑钠尿肽前体（NT-proBNP）、6分钟步行距离（6MWT）]、焦虑抑郁[汉密尔顿焦虑量表（HAMA）、汉密尔顿抑郁量表（HAMD）]、睡眠质量[匹兹堡睡眠质量指数（PSQI）]及生活质量[采用西雅图生活质量量表（SAQ）,包括躯体活动受限程度（PL）、心绞痛稳定情况（AS）、心绞痛发作情况（AF）、治疗满意程度（TS）、疾病认识程度（DS）]评分情况。 结果 两组治疗前血脂指标、心功能指标、焦虑抑郁、睡眠质量及生活质量评分比较差异均无统计学意义;干预组治疗后TC、TG、LDL-C、HDL-C、NT-proBNP、HAMA、HAMD、PSQI均较本组治疗前和对照组治疗后显著下降,LVEF、6MWT、PL、AS、AF、TS、DS均较本组治疗前和对照组治疗后显著升高（均P<0.05）。 结论 穴位按摩联合心脏康复操可显著改善PCI术后患者血脂水平,提高心功能,缓解焦虑、抑郁等不良情绪,提高睡眠及生活质量,临床疗效满意。     

错配修复蛋白和p53蛋白在结直肠癌中的表达及其临床意义

背景:研究表明,结直肠癌的主要发病途径有两条,即染色体不稳定性途径和微卫星不稳定性(MSI)途径。目的:探讨错配修复蛋白(MMRP)和p53蛋白在结直肠癌中的表达及其临床意义。方法:采用免疫组化SP法检测2013年1月—2017年12月上海市嘉定区中心医院收治的276例结直肠癌中4种MMRP和p53蛋白表达,并分析其与临床病理特征的关系。分析MSI对结直肠癌患者生存情况的影响。结果:MMRP表达缺失36例(13.0%),MSI与组织病理学类型、TNM分期和血吸虫感染有关(P<0.05),而与患者性别、年龄、发病部位、分化程度和淋巴结转移均无关(P>0.05)。p53蛋白在结直肠癌中的阳性表达率为44.9%,其表达与组织病理学类型、TNM分期、淋巴结转移和血吸虫感染有关(P<0.05),而与患者性别、年龄、发病部位和分化程度均无关(P>0.05)。MSI与p53表达呈负相关(r=-0.169,P<0.05)。MSI组和MSS组的1、3、5年生存率分别为100%、97.2%、83.1%和96.7%、81.9%、38.9%,差异有统计学意义(χ^2=12.582,P=0.001)。结论:MSI和p53表达与结直肠癌的临床病理特征关系密切,对肿瘤的恶性程度和预后的判断有指导意义。MSI与p53表达呈负相关,提示两者可能参与结直肠癌不同阶段的发生、发展过程。     

Repair of an articular cartilage defect using adipose-derived stem cells loaded on a polyelectrolyte complex scaffold based on poly(l-glutamic acid) and chitosan

As a synthetic polypeptide water-soluble poly(l-glutamic acid) (PLGA) was designed to fabricate scaffolds for cartilage tissue engineering. Chitosan (CHI) has been employed as a physical cross-linking component in the construction of scaffolds. PLGA/CHI scaffolds act as sponges with a swelling ratio of 760 ± 45% (mass%), showing promising biocompatibility and biodegradation. Autologous adipose-derived stem cells (ASCs) were expanded and seeded on PLGA/CHI scaffolds, ASC/scaffold constructs were then subjected to chondrogenic induction in vitro for 2 weeks. The results showed that PLGA/CHI scaffolds could effectively support ASC adherence, proliferation and chondrogenic differentiation. The ASCs/scaffold constructs were then transplanted to repair full thickness articular cartilage defects (4 mm in diameter, to the depth of subchondral bone) created in rabbit femur trochlea. Histological observations found that articular defects were covered with newly formed cartilage 6 weeks post-implantation. After 12 weeks the regenerated cartilage had integrated well with the surrounding native cartilage and subchondral bone. Toluidine blue and immunohistochemical staining confirmed similar accumulation of glycosaminoglycans and type II collagen in engineered cartilage as in native cartilage 12 weeks post-implantation. The result was further supported by quantitative analysis of extracellular matrix deposition. The compressive modulus of the engineered cartilage increased significantly from 30% of that of normal cartilage at 6 weeks to 83% at 12 weeks. Cyto-nanoindentation also showed analogous biomechanical behavior of the engineered cartilage to that of native cartilage. The results of the present study thus demonstrate the potentiality of PLGA/CHI scaffolds in cartilage tissue engineering.