PES中空纤维复合纳滤膜的制备

采用界面聚合法制备聚醚砜（PES）中空纤维复合纳滤（NF）膜，讨论了制备条件对PES中空纤维复合NF膜性能的影响。实验结果表明，聚合反应时间、均苯三甲酰氯浓度、哌嗪浓度和酸吸收剂三乙胺浓度对复合NF膜性能有显著影响，同时二次反应能够提高复合NF膜的截留率，对2g／L的Na2SO4截留率可达到99．2％。     

PSF-SPES共混中空纤维超滤膜制备的研究

以聚砜(PSF)、磺化聚醚砜(SPES)和醋酸纤维素(CA)为膜材料,水为内凝胶剂,采用干湿法制备了PSF-SPES共混中空纤维超滤膜,探讨了PSF-SPES铸膜液中SPES离子交换容量(IEC)、SPES浓度、添加剂、外凝胶剂的选择和热处理对膜性能的影响。所得共混超滤膜性能如下:w=0.0 0 1的Na2SO4截留率19.9%,通量62 L/(h.m2.MPa);w=0.001的PEG4000截留率78.2%,通量85 L/(h.m2.MPa)。此外,以PSF-SPES中空纤维为支撑膜,采用醋酸纤维素作为涂层液,研究了CA/PSF-SPES复合超滤膜性能,讨论了CA/PSF-SPES共混中空纤维超滤膜结构。     

聚醚砜/酚酞基聚醚砜共混相容性及凝胶特性研究

采用混合热焓法和稀溶液粘度法预测了聚醚砜/酚酞基聚醚砜体系相容性,并观察了聚醚砜/酚酞基聚醚砜共混制膜液的凝胶值与共混比的关系.聚醚砜/酚酞基聚醚砜为部分相容体系,其相容性与组成有关.共混制膜液的凝胶值受共混组成的影响,并非纯组分制膜液凝胶值的线性加和.     

聚醚砜溶液流变性的研究

研究了聚醚砜（PES）/二甲基亚砜（DMSO）体系中PES的质量分数、原液温度对流变性的影响和原液中PES的质量分数对粘流活化能的影响,从而得出PES/DMSO体系属于切力变稀流体,非牛顿指数随着PES质量分数的增加而不断减小,随着溶液温度的升高而不断增大.     

聚（氯乙烯-醋酸乙烯酯）与热塑性聚氨酯的 相容性及其共混膜的氧化稳定性

采用溶液法制备了聚（氯乙烯-醋酸乙烯酯）（PVCAc）与热塑性聚醚型聚氨酯(TPU)的共混膜(PUV)。通过FT-IR和DSC对膜的形态和相容性进行了研究。与聚氯乙烯(PVC)相比,PVCAc与TPU的相容性明显增强。将PUV膜浸没于H2O2-CoCl2溶液中25 d进行加速氧化实验,结果表明：PUV膜的氧化稳定性优于TPU和TPU/PVC的共混膜(PUC)。此外,PUV膜的力学性能明显高于PUC膜。     

银/聚电解质复合纳滤膜的制备及表征

利用层层自组装技术(LbL),采用原位还原方法在聚醚砜(PES)基膜上制备了银/聚电解质复合纳滤膜.SEM分析表明:膜表面结构致密,Ag粒子在复合膜中分布均匀,粒径100～200 nm,UV-vis图谱证明膜中粒子为Ag粒子,所得银/聚电解质纳滤膜呈现出优异的抗菌性能.[PSS/PDADMAC]3[PAS/PAH-Ag]3PSS膜对负二价离子显示出较高的截留性能,达到93%.     

聚醚砜超滤膜对茯苓多糖的静态吸附行为与解吸方法的考察

目的 研究茯苓多糖超滤前后在聚醚砜（PES）-1万膜上的静态等温吸附模型以及解吸方法。方法 蒽酮-硫酸法测定茯苓多糖的含量,考察不同初始浓度的茯苓多糖在PES膜上的吸附效果,绘制吸附等温线,根据吸附平衡数据拟合吸附方程。并以解吸率为指标,考察不同pH解吸溶液的解吸效果。结果 茯苓多糖在PES-1万膜上吸附符合Freundlich模型,pH为8的碳酸氢钠和碳酸钠缓冲溶液为解吸剂的解吸效果最佳。结论 PES-1万膜对茯苓多糖有吸附作用,其吸附行为与解吸方法为中药活性成分的资源化回收提供了依据。      

小分子醇对PVDF/PFSA共混膜凝胶动力学、膜结构及膜性能的影响

以小分子醇为添加剂,研究了小分子醇对聚偏氟乙烯(PVDF)/全氟磺酸(PFSA)共混超滤膜凝胶动力学、结构与渗透性能的影响.结果表明:在PVDF/PFSA铸膜液中添加乙醇时,其凝胶速率随乙醇浓度的增加而加快,超滤膜通量随乙醇浓度的增加而增大;而当添加相同浓度的4种小分子醇时,初始凝胶速率差别不大,20 s后添加乙醇的铸膜液的凝胶速率最大;添加小分子醇后超滤膜的水通量大小顺序为:异丙醇<甲醇<乙醇<正丁醇.SEM照片显示在铸膜液中添加5%乙醇所制备的共混超滤膜具有较为圆整的内腔结构与均匀的孔结构.     

超滤浓缩技术分离鹿茸中胰岛素样生长因子-1

目的 建立鹿茸中胰岛素样生长因子-1（IGF-1）的超滤浓缩工艺。方法 以鹿茸冻干粉为原料,采用超滤技术对IGF-1的超滤浓缩工艺进行考察。以聚醚砜（PES）膜和改性PES膜进行对比研究,考察截留相对分子质量、压力、pH值等因素对鹿茸冻干粉超声提取液超滤浓缩过程的影响,并对超滤膜的清洗方法进行考察,得出适宜的工艺条件。结果 最优工艺条件为截留相对分子质量：PES膜4 000,改性PES膜5 000;压力为0.3 MPa,pH值为12。在此条件下,PES膜IGF-1回收率达到68.32%,蛋白质回收率达到69.20%;改性PES膜IGF-1回收率达到57.17%,蛋白质回收率达到87.43%。采用4种不同的方法对超滤膜进行清洗,结果表明,超滤膜在0.4% NaOH-0.1% NaClO溶液中浸泡24 h,PES膜膜通量恢复率达到98.65%,改性PES膜膜通量恢复率达到93.75%,膜通量接近完全恢复。结论 采用优化的超滤浓缩技术能够达到浓缩分离IGF-1的目的。该工艺操作简单、稳定,超滤膜易于清洗,回收率高,具有工业化生产应用价值。     

环氧树脂/聚醚砜/纳米氧化铝复合材料的力学性能及介电性能

以甲基纳迪克酸酐（MNA）为固化剂,制备了环氧树脂/聚醚砜/纳米氧化铝三元复合材料,并对其力学性能、介电性能以及热稳定性能进行了研究,同时探讨了其性能增强机理。结果表明：当聚醚砜（PES）和纳米氧化铝（nano-Al₂O₃）的质量分数分别为15%和3%时,环氧树脂/15PES/3Al₂O₃复合材料的冲击强度、拉伸强度和弯曲强度分别达到45.7 kJ/m²、87 MPa和180 MPa,与纯环氧树脂相比,均有大幅度的提高。在测试频率为100 Hz时,复合材料的介电常数和介电损耗分别为7.7和0.013 5,介电性能较纯环氧树脂也有一定提高。此外,热分解温度比纯环氧树脂的提高了73℃,热稳定性得到提高。     

电刺激家兔大脑皮层感觉区对丘脑束旁核痛敏单位放电活动的影响

<正> 目前倾向认为,脊髓背角和丘脑束旁核是传递与感受疼痛的关键部位,也是中枢神经系统内上行或下行痛觉调制系统的主要作用部位。业已迂实,大脑皮层扣带回、尾核、丘脑中央中核、中脑导水管周围灰质以及中缝核群等核同兴奋时均可分别经由各自的上行或下行通路作用于这两个部位,对痛觉进行复杂的调制。既然大脑皮层感觉区对某些感觉功能有下行性调制作用;并且有纤维投射到丘脑束旁核和脊髓     

Different edge effects of paclitaxel- and sirolimus-eluting stents on proximal and distal edges in patients with unstable angina: serial intravascular ultrasound analysis

Background It is unclear whether edge segments have different responses to paclitaxel eluting stent （PES） and sirolimus eluting stent （SES） implantation in patients with unstable angina. This study aimed to compare the different vascular edge responses in patients with unstable angina and single de novo coronary lesion treated with SES and PES. Methods Two hundred and fifty-five patients with unstable angina and single de novo lesion were randomly assigned to PES and SES groups. Serial volumetric intravascular ultrasound （IVUS） images were taken immediately after stenting and at an eight-month follow-up. Five-mm edge segments proximal and distal to the stents were analyzed. Results Baseline characteristics were comparable between the two groups. At proximal-edge segment, the vessel area decreased and the plaque area increased significantly in the PES group as compared with the SES group. A significant net loss of lumen area was found in the PES group （from （11.10±3.12） mm^2 at baseline to （9.92±3.59） mm^2 at the follow-up, P 〈0.001）. At the distal-edge segment, the net loss of lumen area in the PES group （from （7.71±2.81） mm^2 at baseline to （6.66±2.29） mm^2 at the follow-up, P 〈0.001） was attributed to a significant increase of plaque area. Proximal-edge stenosis was commonly seen in the PES group （20.0%） as compared with the SES group （5.0%, P=0.001）. This correlated with the higher incidence of target lesion revascularization in the PES group （P=0.03）. Subsegmentally, the smallest A lumen area was located at 2 mm proximally in both groups, at 0 mm distally in the PES group, and at 1 mm distally in the SES group. Conclusions The two groups demonstrated negative remodeling of edge segments. PES was less effective than SES in inhibiting the growth of plaque within the first 1-mm length proximal to the stent.     

Crush stenting in treating coronary bifurcate lesions: paclitaxel eluting stents versus sirolimus eluting stents

Background Because no data regarding the comparison of crush stenting with paclitaxel （PES） or sirolimus eluting stents （SES） for coronary bifurcate lesions have been reported, we compared the clinical outcomes of these two types of stents. Methods Two hundred and thirty patients with 242 bifurcate lesions were enrolled in a prospective, nonrandomized trial Primary endpoints included myocardial infarction, cardiac death and target vessel revascularization at 8 months. Results All patients were followed up clinically and 82% angiographically at 8 months. Final kissing balloon inflation was performed in 72% in the PES and 75% in the SES groups （P〉0.05）. Compared to the SES group, PES group had a higher late loss and incidence of restenosis （P=0.04） in the prebifurcation vessel segment. The postbifurcation vessel segment in the PES group had a greater late loss （（0.7±0.6） mm vs （0.3±0.4） mm, P〈0.001） and higher restenosis in the side branch （25.5% vs 15.6%, P=0.04） when compared to the SES group. There was significant difference of insegment restenosis in the entire main vessel between PES and SES groups （P=0.004）. Target lesion revascularization was more frequently seen in the PES group as compared to the SES group （P=0.01）. There was significant difference in the accumulative MACE between these two groups （P=-0.01）. The survival rate free from target lesion revascularization was significantly higher in the SES group when compared to the PES group （P〈0.001）. Conclusion SES is superior to PES in reducing restenosis and target lesion revascularization by 8-month follow-up after crush stenting for bifurcate lesions.     

The effect of gastric overfilling on the pharyngo-esophageal and lower esophageal sphincter: a possible factor in restricting food intake.

BACKGROUND: How afferent activity in the gut achieves the required ingestion control has not been established. The authors hypothesized that gastric overdistension effects an increase in pharyngo-esophageal and lower esophageal sphincter activity aimed at inhibiting ingestion. MATERIAL/METHODS: The study comprised 16 mongrel dogs. Under anesthesia, one balloon-tipped catheter was placed in the stomach, another within the lower esophageal sphincter (LES), and a third within the pharyngo-esophageal sphincter (PES). The gastric balloon was filled with H(2)O in increments of 10 ml and LES and PES pressures were recorded. The test was repeated after individual gastric, LES, and PES anesthetization. RESULTS: Gastric balloon filling with more than 20 ml of H(2)O showed progressively increasing LES pressure up to 110-120 ml of gastric filling, beyond which the pressure exhibited no further increase upon incrementally increased gastric filling volume. PES pressure increased only with a gastric filling volume exceeding 100-110 ml and continued to increase with increasing gastric filling. Gastric filling as above while the stomach, LES, and PES were separately anesthetized produced no LES or PES pressure response. CONCLUSIONS: LES and PES appear to contract on gastric filling; PES responds only to excess gastric filling. It seems that LES and PES response to gastric filling is mediated through a reflex which the authors call the "gastro-esophagopharyngeal reflex" (GEPR). Changes in the evoked response would indicate a defect in the reflex pathway. GEPR might thus serve as an investigative tool in the diagnosis of gastroesophageal disorders, although further studies are required.     

外周电刺激抑制大鼠吗啡条件性位置偏爱的复发及海洛因成瘾者的心瘾

目的:探讨外周电刺激(PES)是否能频率依赖性地抑制吗啡条件性位置偏爱(CPP)的复发和抑制海洛因成瘾者脱毒后的心瘾.方法:用二室自动CPP箱记录大鼠条件性CPP,用视觉模拟尺测量海洛因成瘾者的"心瘾(渴求)".结果:(1)低频PES能抑制大鼠小剂量吗啡点燃、或脚底电刺激诱发的吗啡CPP;(2)上述效应可被小剂量吗啡受体拮抗剂纳洛酮(1 mg*kg-1)翻转,提示有内源性阿片机制参与;(3)低频PES还能使海洛因成瘾者脱毒后对毒品"心瘾"的自然消退过程加速.结论:外周神经电刺激可能是治疗海洛因成瘾的一种有效方法.     

聚醚砜膜对星形胶质细胞生物学行为的影响

目的研究聚醚砜膜对星形胶质细胞(AST)生长、存活增殖及分泌神经营养因子的影响。方法取小鼠皮层组织进行AST原代培养,传代纯化培养后分为3组:A普通培养板组;B聚醚砜膜组;C层粘连蛋白包被膜组,观察和比较细胞形态学、细胞存活增殖能力的变化,同时测定培养基中神经生长因子(NGF)、脑源性生长因子(BDNF)含量。结果在原代和传代培养期,聚醚砜膜上培养第3天后的AST细胞数较其他组明显减少(P<0.05)。在传代培养期,3组的细胞存活增殖能力均在第7天后逐渐衰退,分泌NGF和BDNF的能力也呈相同的下降趋势,聚醚砜膜组AST的变化较另外2组的变化更为明显(P<0.05)。结论聚醚砜膜对星形胶质细胞的存活增殖有一定抑制作用,并降低AST分泌NGF和BDNF的能力,层粘连蛋白可在一定程度上减轻聚醚砜膜对AST功能的抑制作用。     

AMI后体表心室晚电位与程序电刺激诱发恶性室性心律失常的关系

本文探讨急性心肌梗塞后心室晚电位与程序电刺激诱发持续性室性心动过速、心室纤颤的关系。17只犬心肌梗塞后3～5天,13只体表记录到心室晚电位,其中12只诱发了持续性室性心动过速或/和心室纤颤(94.11％,P<0.01)。结果提示:心室晚电位的出现与程序电刺激诱发持续性室性心动过速、心室纤颤有明显相关性。     

跨声门癌浸润喉间隙的特点

目的：探讨跨声门癌浸润声门旁间隙和会厌前间隙的特点及与颈淋巴结转移关系。方法：对５０例跨声门癌喉切除标本和３０例３５侧颈廓清大体标本行连续切片观察。结果：声门旁间隙的浸润率为７８％ ,颈淋巴结转移率为４９％ 。会厌前间隙的浸润率为４６％ ,颈淋巴结转移率为６５％ 。随着肿瘤Ｔ分级增高,肿瘤增大,声门旁间隙和会厌前间隙的浸润率增加。结论：声门旁间隙易受累,并易突破该间隙;浸润会厌前间隙的途径与声门上癌不同,支持跨声门癌为单独一型,应慎行部分喉切除术