基于电刺激的外层型人工视网膜的研究进展

外层型视网膜假体采用了MEMS技术,通过植入到视网膜相应部位的电极来刺激神经节细胞,并且能够在大脑皮层视觉区域引起对应的特征电位反应,最终部分恢复生物体的视觉.这种外层型视网膜植入装置可分为眼外和眼内部分.后者功能相对重要,设计也较为复杂.它是由包含MPDA和微电极的刺激芯片及附属装置组成.本篇文章主体包括四部分:首先是视网膜假体的概况;其次是视网膜生理基础和视网膜假体理论的简介;在第三部分,为设计理念和MPDA的制造过程;最后,是对难题的讨论和未来发展的展望.     

STAT3 couples with 14-3-3σ to regulate BCR signaling,B-cell differentiation,and IgE production

1. Download : Download high-res image (205KB)
2. Download : Download full-size image

     

Morphology and Thermal Properties of MCPA6/ABS by in situ Polymerization of ε‐Caprolactam

Summary: In this work, blends of monomer casting polyamide 6 (MCPA6) and acrylonitrile‐butadiene‐styrene (ABS) were successfully prepared by in situ polymerization via the application of ε‐caprolactam as a reactive solvent. The morphology and thermal properties of MCPA6/ABS were investigated by means of wide angle X‐ray diffraction (WAXD), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM), respectively. The domain sizes of the ABS phase in MCPA6/ABS blends were much finer than those in corresponding polyamide 6 (PA6)/ABS blends prepared by simple melt blending. With an increased amount of ABS in MCPA6, the melt enthalpy (ΔH_f), the rate of crystallization (T_c) and the degree of crystallinity (X_c(DSC)) of MCPA6 in MCPA6/ABS blends were all decreased. The degree of supercooling (ΔT_d) showed a contrary trend. However, the melting temperatures of these blends were almost unchanged. All the results could be attributed to in situ polymerization and the hydrolysis reaction of ABS that occurred during the polymerization process. Furthermore, WAXD results showed that only α‐form crystals existed in the MCPA6/ABS blends, despite the ABS content and heat treatment.

SEM micrograph of the fractured surface of an MCPA6/ABS blend with an ABS content of 20 wt.‐% (×10 000).     

Schistosomiasis: an unusual cause of tubal infertility

A case report of a Nigerian woman having an unusual cause oftubal infertility is presented. On histological examinationof the Fallopian tube, ova of Schistosoma haematobium enclosingliving miracidia were found in the smooth muscle layer of theFallopian tube and its mesosalpinx. Mechanisms of tubal involvementare analysed. The case indicates the need to consider schisto-somiasisas a possible aetiological factor in patients with tubal infertilitycoming from areas where the disease is endemic.     

维生素A阻抑大鼠实验性肝纤维化的病理研究

利用光镜、电镜、免疫组化和形态学定量技术动态研究维生素A对大鼠四氯化碳肝纤维化的抑制作用。结果表明,维生素A可减少四氯化碳中毒大鼠肝内纤维连接蛋白和Ⅰ、Ⅲ型胶原沉积,抑制贮脂细胞向成纤维细胞转化,并可明显地减轻肝纤维化程度。本文还对维生素A抑制肝纤维化的机理及意义作了初步探讨。     

Histidinuria: A renal and intestinal histidine transport deficiency found in two mentally retarded children

Two siblings presenting slight mental retardation showed an abnormal elimination of histidine, their blood levels for the same amino acid being normal. The percentage of tubular resorption of histidine was calculated in both boys, and the values were 40.1 per cent (case 1) and 52.8 per cent (case 2). All other amino acids essayed were normal. After an oral overload test with histidine, a low intestinal absorption was found in the two boys, the values of this test in the parents being intermediate between those of the children and of the three normal controls and corresponding to heterozygosity. In view of the studies carried out on the two boys, it is possible to conclude that they are suffering from an impairment in their histidine membrane transport system which affects the kidney and intestines. Since they are siblings a genetically determined trait may be suspected.     

川崎病休克综合征合并心力衰竭1例临床病例分析及文献复习

目的 探讨川崎病休克综合征 (Kawasaki Disease Shock Syndrome,KDSS) 合并心力衰竭的临床特征。方法 分析 1例KDSS合并心力衰竭患儿的临床资料,并复习相关文献。结果 KDSS在川崎病中不常见,但表现严重,在急性期可以导致循环衰竭,表现为心动过速、毛细血管充盈时间延长、四肢末端发凉、脉搏细弱、尿量减少或意识障碍等而发生全身循环衰竭,早期识别,及时给予人免疫球蛋白和激素等综合治疗可明显改善患者休克的状况。结论 KDSS是川崎病中少见但较为严重的临床并发症,早期识别及综合的临床治疗方法是减少KDSS的有效措施。     

Recurrent infections and chronic colonization by an Escherichia coli clone in the respiratory tract of a patient with severe cystic bronchiectasis

A 39-year-old woman with cystic bronchiectasis had repeated pulmonary infections from 1996 to 1999, and 6 of a total of 28 isolates of Escherichia coli from sputum specimens were studied. Their identical antibiotype and randomly amplified polymorphic DNA patterns indicated a single clone of E. coli, which persistently colonized the respiratory tract, causing recurrent infections.     

No association between schizophrenia and homozygosity at the D3 dopamine receptor gene

The D₃ dopamine receptor gene is an important candidate gene for schizophrenia, since (because of its almost exclusive expression in the limbic system) it combines the dopamine receptor hypothesis with the limbic system hypothesis of schizophrenia. A BalI restriction fragment length polymorphism of the D₃ dopamine receptor gene has been typed in 107 schizophrenic patients and 98 normal controls from Sichuan (China). With regard to alleles or genotypes, no significant differences were obtained between controls from Europe and China, between patients and controls, and between patient subgroups and controls. These results indicate a lack of association between schizophrenia and the D₃ dopamine receptor gene in our sample. Our findings are at variance with reports of a significant excess of homozygosity at the D₃ dopamine receptor gene in schizophrenic patients from Wales (United Kingdom) and Alsace (France). In conclusion, further studies will be needed with larger samples of patients from Wales and Alsace as well as with samples of different racial groups to prove or disprove the initial positive association between schizophrenia and genotypes of the D₃ dopamine receptor gene. © 1993 Wiley-Liss, Inc.     

Extralobar pulmonary sequestration with an associated cyst of mixed bronchogenic and esophageal type--a case report.

We report an unusual case of extralobar pulmonary sequestration (ELS) with an associated cyst of mixed bronchogenic and esophageal type. A 58-year-old woman was incidentally found to have a 6 x 6 x 5 cm sized mass in the right superior mediastinum. The mass consisted of sequestrated pulmonary tissue and an unilocular cyst with a direct communication. The cyst could not be easily classified because it was lined by squamous or respiratory epithelium with two distinct muscle layers and bronchial glands. Bronchial cartilage was present in close proximity to the ELS. This unusual combination of ELS with a foregut cyst might be a part of bronchopulmonary foregut malformation, attributed to a common embryologic pathogenesis.