脂肪族聚酯与高氯酸锂络合物的结构与导电性

本文通过酯交换反应合成了一系列脂肪族聚丁二酸酯,对他们的结构和性能作了表征。发现聚酯存在多晶现象,其熔点有奇偶性变化规律。探索了由此系列聚酯与高氯酸锂形成的固体电解质的结构和离子导电性。无机盐的加入提高了电解质的玻璃化温度但降低了聚酯的熔点及结晶度。聚酯电解质的晶体类似于聚酯,其无机盐主要溶解于聚酯的无定形区域。聚酯系列电解质的导电率也有偶奇效应,与熔点变化相反;熔点高的电解质导电率低,熔点低的电解质导电率高。电解质的导电率随温度改变而变化,在室温下电解质的导电率可达10~(-6)s/cm。高分子链上侧基的引入将大大降低电解质的导电性。     

玻璃体腔内注气治疗黄斑裂孔视网膜脱离

采用玻璃体腔内注气治疗黄斑裂孔视网膜脱离４９例（５３只眼），视风膜复位４２只眼（７９．２％），其中术后视力增进２９只眼（６９％），讨论了注气的适应征和影响视网膜复位的因素。     

多处钻孔治疗颅底动脉闭塞征临床研究

目的 评价多处钻孔法治疗颅底动脉闭塞征(Moyamoya病)的可行性。方法 对20例Moyamoya病患者行多处钻孔及联合双侧颈动脉外膜剥脱术。钻孔位置依据DSA及ECT所示的缺血区而定。结果 本组除1例视力障碍者临床症状无明显改善外，余19例临床症状均有较明显的改善，部分病例术后原血流减少部位血供均有比较明显的改善。有效率达95％，无死亡病例，无感染及切口愈合不良等并发症发生。结论 多处钻孔法具有操作简单、新生血管出现较早等优点，可单独用于临床或作为直接血行重建术的补充疗法。     

直接甲醇燃料电池用阻醇质子导电聚乙烯醇-聚苯乙烯磺酸共混膜

制备了聚乙烯醇 (PVA)与聚苯乙烯磺酸 (PSSA)的共混膜 ,并研究了膜的组成、热处理温度、甲醇水溶液浓度等对膜电导率和甲醇透过率的影响。与目前普遍使用的NafionTM膜相比 ,这种由阻醇材料PVA与离子交换材料PSSA共混后形成的聚合物膜既能提高阻醇性能 ,又具有一定的电导率。一种以聚苯乙烯磺酸含量为 17%的膜 ,其电导率可达 3× 10 -3 S·cm-1,但甲醇透过率P仅为 2× 10 -8cm2 ·s-1。如果以σ/P为综合指标 ,则此膜的综合性能比NafionTM膜高约 4 0倍     

黄斑裂孔的游标高敏视力特征

目的　探讨游标高敏视力检测黄斑裂孔眼视功能的临床应用价值。方法　采用自行研究设计的游标高敏视力检查系统软件 ,对 2 7例 (2 7只眼 )黄斑裂孔患者进行游标高敏视力检查 (其中 16例 16只眼经手术前后对比 ) ,受检者按要求判断计算机显示屏上活动光标与固定光标的相对位置关系 ,并通过移动轨迹球调整光标 ,计算机自动分析活动光标和固定光标位置之偏差 ,得出平均阈值及其变异度。结果　黄斑裂孔组的游标高敏视力阈值与同龄正常组比较明显升高 ,阈值变异度增大 ,与正常眼比较差异均有非常显著性 (P<0 .0 1)。手术治疗组术前术后游标高敏视力比较 ,阈值的差异无显著性 (P>0 .0 5 ) ,阈值变异度差异有显著性 (P<0 .0 5 )。黄斑裂孔视力与游标视力阈值的相关系数为 - 0 .79,与游标视力阈值变异度的相关系数为 - 0 .85。结论　游标高敏视力的阈值及其变异度的高低是反映黄斑裂孔病变轻重的一个功能指标 ,对于辅助早期诊断、分类具有一定的临床应用价值。     

Polyelectrolyte‐in‐Ionic‐Liquid Electrolytes

Novel polymer electrolyte materials based on a polyelectrolyte‐in‐ionic‐liquid principle are described. A combination of a lithium 2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid (AMPSLi) and N,N′‐dimethylacrylamide (DMMA) are miscible with the ionic liquid, 1‐ethyl‐3‐methylimidazolium dicyanamide (EMIDCA). EMIDCA has remarkably high conductivity (≥ 2 · 10^?2 S · cm^?1) at room temperature and acts as a good solvating medium for the polyelectrolyte. At compositions of AMPSLi less than or equal to 75 mol‐% in the copolymer (P(AMPSLi‐co‐DMAA)), the polyelectrolytes in EMIDCA are homogeneous, flexible elastomeric gel materials at 10 ? 15 wt.‐% of total polyelectrolyte. Conductivities higher than 8 · 10^?3 S · cm^?1 at 30 °C have been achieved. The effects of the monomer composition, polyelectrolyte concentration, temperature and lithium concentration on the ionic conductivity have been studied using thermal and conductivity analysis, and pulsed field gradient nuclear magnetic resonance techniques.

Comparison of the measured and calculated lithium conductivity at 30 °C.     

Ionic conductances of cultured principal cell epithelium of renal collecting duct

The ionic conductive properties were studied of epithelia of collecting duct principal cells which had been grown in primary tissue culture from renal cortex/capsule explants. When pretreated with aldosterone (10^–6 mol/l) and bathed on either surface with isotonic HCO ₃ ^– -free Ringer's solution, the transepithelial voltage,V _te, varied between –21 and –72 mV (apical surface negative) while the transepithelial resistance,R _te, ranged from 0.4 to 1.5 kcm². By 10:1 step-changes in Na⁺ concentration the apical cell membrane was shown to have a high conductivity for sodium, inhibitable by amiloride, 10^–6 mol/l. However, contrary to observations in natural collecting duct under control conditions, amiloride never reversed the polarity ofV _te even at 10^–4 mol/l. Both the apical and the basolateral cell membranes were conductive for potassium and both conductivities were inhibitable by Ba²⁺ (5 mmol/l). 10:1 reduction of apical Cl^– concentration strongly hyperpolarizedV _te with a monophasic time course suggesting the presence of a paracellular shunt conductance for Cl^–. In addition there may be a small Cl^– conductance present in the apical cell membrane since apical application of the chloride channel blocker 5-nitro-2-(3-phenylpropylamino)-benzoic acid (NPPAB) at 10^–7 mol/l produced a minute but significant hyperpolarization. On the other hand, 10:1 reduction of basolateral Cl^– concentration caused a biphasic change inV _te (initial depolarization, followed by repolarization) which indicates the presence of a large Cl^– conductance in the basolateral cell membrane. The latter was not inhibitable by 10^–7 mol/l NPPAB. Higher concentrations of this and of an other Cl^– channel blocker produced non-specific effects. In conclusion, our studies of a pure principal cell epithelium confirm findings described for the intact cortical collecting duct and add new information concerning chloride conductivity and related blocking agents.Dedicated to Prof. Dr. H. Sitte, Homburg, FRG, upon his 60th birthday.     

Comparison of optical, electrical, and centrifugation techniques for haematocrit monitoring of dialysed patients

Haematocrits were measured as a function of ultrafiltration in a simulated haemodialysis circuit using bovine blood (plasma conductivity 12 mS cm-1) and hypotonic (8.6 mS cm-1) or hypertonic (16 mS cm-1) dialysates as well as in the absence of dialysate. A comparison was made between measurements by light absorption due to haemoglobin, by impedance in the blood line at 5 kHz using Hanai's model of blood conductivity, by conductivity measurements of blood samples at 1.2 kHz using a conductimeter, by centrifugation of blood samples and by calculations using fluid conservation. The validity of Hanai's model was verified to be satisfactory by direct blood and plasma conductivity measurements. In the absence of ionic transfer the impedance device underestimated the haematocrit by 5 to 7%. This underestimation reached 18% in the case of hypertonic dialysate, but this effect can be minimised if the haematocrit necessary for calibration is measured by centrifugation after 15 min of dialysate circulation when ionic balance is achieved. It was found that the optical method monitors haemoglobin concentration rather than red cell volume changes and is not affected by osmotic red cell swelling in the case of hypotonic dialysate. It can be concluded that the light absorption technique is both more accurate and more convenient to use than impedance.     

Transport of molecules across tumor vasculature

The vascular-extravascular exchange of fluid and solute molecules in a tissue is determined by three transport parameters (vascular permeability, P, hydraulic conductivity, L_p, and reflection coefficient, ); the surface area for exchange, A; and the transluminal concentration and pressure gradients. The transport parameters and the exchange area for a given molecule are governed by the structure of the vessel wall. In general, tumor vessels have wide interendothelial junctions; large number of fenestrae and transendothelial channels formed by vesicles; and discontinuous or absent basement membrane. While these factors favor movement of molecules across tumor vessels, high interstitial pressure and low microvascular pressure may retard extravasation of molecules and cells, especially in large tumors. These characteristics of the transvascular transport have significant implications in tumor growth, metastasis, detection and treatment.     

孔源性视网膜脱离的临床特点

对109眼孔源性视网膜脱离的发病年龄及不同年龄组视网膜脱离与屈光状态,不同年龄组裂孔的形态等关系进行了分析。结果表明40岁以下网脱近视多见,40岁以后网脱近视逐渐减少。圆孔多见于40岁以下年龄组,马蹄形裂孔多见于40岁以上年龄组。