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91.
Ping Zhang Zhenhua Sun Guang Li Yugang Zhuang Mengxiam Ding Zhiliu Feng 《Macromolecular chemistry and physics.》1993,194(7):1871-1877
The structure and miscibility of polyimide PBPI-E/PTI-E blends were studied by wide- and small-angle X-ray scattering and dynamic mechanical analysis, where PBPI-E is a biphenyldianhydride-based polyimide, and PTI-E is a polyimide from 4,4′-thiodiphthalic anhydride and 4,4′-oxydianiline. The results obtained show that there exists a paracrystalline structure in the blends with high content of PBPI-E, but this does not affect the miscibility of the blends. The blends are miscible over the entire composition range, since only one Tg was observed for each blend. Meanwhile, the segregation of PTI-E during crystallization of PBPI-E in the blends is interlamellar. 相似文献
92.
经皮穿刺椎间盘髓核摘除术入路的研究 总被引:1,自引:0,他引:1
为提供椎间盘髓核摘除术形态学依据,在7具成人横断面标本上观察测量了L1~L5椎间盘平面经皮穿刺椎间盘髓核摘除术的进针点、角度和深度。发现在L1~L3、L4~L5椎间盘髓核的穿刺点以距后正中线8~10cm,9~11cm,穿刺角度以46.7°~59.5°,穿刺深度为110.2~128.9mm为最宜。 相似文献
93.
Bai Y Ding Y Spencer S Lasky LA Bromberg JS 《Experimental and molecular pathology》2001,71(2):115-124
Prominent in T cells and natural killer cells, CD2 binding protein 1 (CD2BP1) plays an important role in CD2-mediated adhesion and signal transduction. In the current study, we investigated CD2 and PSTPIP (proline, serine, threonine phosphatase interacting protein, murine homologue of CD2BP1) interactions in purified mouse splenic T cells. PSTPIP associated with CD2 in both resting and activated T cells. Following various stimuli, such as concanavalin A, anti-TCRbeta, anti-CD3epsilon, anti-CD3epsilon/phorbol myristate acetate (PMA), IL-2, or PMA/ionomycin, PSTPIP and CD2 expression, as well as their association, increased in a time-dependent fashion. While PSTPIP expression and CD2 expression were comparable across most groups, the PSTPIP-CD2 association stimulated by anti-CD3epsilon alone was significantly greater than with other stimuli. Stimulation by anti-CD3epsilon plus anti-CD28 induced even greater PSTPIP-CD2 association than anti-CD3epsilon treatment alone, indicating that CD28 initiated signals are involved in regulating this interaction. There was no direct association between CD3epsilon or CD28 and PSTPIP. Tyrosine phosphorylated PSTPIP bound poorly to CD2 compared to dephosphorylated PSTPIP, and protein tyrosine phosphatase was shown to affect both phosphorylation of PSTPIP and the CD2-PSTPIP association. In addition to CD2, PSTPIP associated with CD4, CD8, CD54, and CD62L. CD2 and CD4 ligation reciprocally regulated their association with PSTPIP. These findings indicate that T cell activation, particularly through the CD3 and CD28 signal transduction pathways, regulates PSTPIP-CD2 interactions. PSTPIP likely has additional broader effects through interactions with CD4, CD8, CD54, and CD62L, and this may influence T cell responses to antigen. 相似文献
94.
对73例门诊Ⅱ度烧伤病人行清创后辐照猪皮一次性覆盖,不需任何其他附加治疗。结果表明,烧伤剖面平均愈合时间只需7天.治愈率达92%,愈合剖面光滑整洁。这一疗法,不仅减轻了因多次换药给病人带来恐惧、痛苦和经济负担,也减少了医生的工作负荷。我们认为:在基层医疗单位,用辐照猪皮覆盖Ⅱ度烧伤剖面是行之有效的治疗方法。 相似文献
95.
Yang BZ Ding JH Zhou C Dimachkie MM Sweetman L Dasouki MJ Wilkinson J Roe CR 《Molecular genetics and metabolism》2000,69(3):259-262
A novel mutation was identified in two unrelated patients with medium-chain acyl-CoA dehydrogenase deficiency. First, a 19-year-old Caucasian female presented with a devastating illness, resulting in sudden death in adulthood which is unusual. The second patient, now a 3.5-year-old male, presented at 17 months of age with a hypoglycemic seizure and dehydration. Sequence analysis revealed a novel mutation G617T in exon 8 resulting in an arginine to leucine substitution at codon 206 (R206L). Both patients were compound heterozygous for this G617T and the common mutation A985G. 相似文献
96.
大鼠再生肝对二乙基亚硝胺启动作用的敏感性 总被引:2,自引:0,他引:2
目的比较再生肝和正常肝对二乙基亚硝胺(DEN)启动作用的敏感性。方法以2/3肝叶切除后8周末的大鼠为实验组,正常大鼠为对照组,作如下比较:肝重、常规组织学检查及3H-TdR掺入试验;用修改的Solt-Farber模型,通过对GGT阳性癌前病灶的体视学测量,观察肝脏对DEN的启动效应;在体内和体外(无血清原代培养肝细胞)经DEN攻击后,以核酸原位缺口标记方法观察肝细胞DNA的损伤程度。结果2/3肝叶切除后8周末的实验组肝脏的修复过程已完成,未见肝细胞继续增生的表现;经DEN攻击后,实验组肝癌前病灶在数密度和体积密度上都显著高于对照组;无论在体内或体外接受DEN攻击后,实验组肝细胞DNA的损伤程度都显著大于对照组。结论即使再生过程已经完成,再生肝仍比正常肝具有较高的致癌敏感性,这与再生肝肝细胞在DEN攻击后其DNA损伤较重相关。 相似文献
97.
作为文章[1]的继续,本文在文章[1]的分析结果基础上,针对壁面对称和非对称狭窄的两种不同情况,通过数值计算给出弯曲狭窄血管内血流的轴向和周向切应力的分布曲线,并讨论其随管壁面几何参数的变化情况。同时,还讨论壁面几何参数对平均血流量和压力降影响的规律。从中发现,当狭窄较轻时(λ<0.2),壁面切应力、平均流量和压力降受狭窄度(λ)的影响不大,而在狭窄较严重时(λ>0.7),狭窄度微小的变化会引起它们急剧变化。此外,在讨论狭窄的非对称性对上述血流动力学参数的影响时还发现,非对称性只对轴向切应力有明显的影响,而对其它参量的影响并不十分显著。 相似文献
98.
Automatic identification of landmarks in cephalometry is very important and useful for orthognathic surgery. A computerised
automatic cephalometric analysis system (CACAS), based on image processing, is presented. For an original X-ray image, median
filtering and histogram equalisation are used to improve image quality. The edge of an X-ray image is detected by a wavelet
transform and Canny filter. Seventeen landmarks in cephalometry are successfully identified by knowledge-based edge tracing
and changeable templates. Seventy-three measurements based on distances, angles and ratios between landmarks are computed
automatically. The reliability of the landmarks and the validity of the measurements are compared for automatic and manual
operation. The values of measurements obtained by CACAS are more precise and reliable: the mean error for linear measurements
is less than 0.9 mm; the mean error for angular measurements is less than 1.2°. The rate of validity is over 80%, even if
the image quality is poor. For an image with a high signal-to-noise ratio, the rate of validity of landmarking and measurements
using the CACAS system is over 90%. 相似文献
99.
Tubular cell senescence and expression of TGF-beta1 and p21(WAF1/CIP1) in tubulointerstitial fibrosis of aging rats 总被引:3,自引:0,他引:3
Ding G Franki N Kapasi AA Reddy K Gibbons N Singhal PC 《Experimental and molecular pathology》2001,70(1):43-53
Kidney aging has been recognized as a chronic process of compromised renal function and structural changes in the tubulointerstitium and glomerulus. Cell senescence is associated with alterations in cell structure and function, including expression of cytokines and structural and regulatory components of extracellular matrix proteins. In this investigation, we tested the hypothesis that senescent renal cells may accumulate in vivo with advancing age. We also evaluated the expression of transforming growth factor (TGF)-beta1 and p21WAF1/CIP1 in aging kidneys. Sprague-Dawley rats at the ages of 3, 12, and 24 months were used for this study. Renal tissues were processed for morphometric and senescence analysis. Expression of TGF-beta1 and p21WAF1/CIP1 was evaluated by Northern or Western blot analysis and immunohistochemistry. Substantial tubulointerstitial injury occurred at the age of 12 months, but significant glomerular structure alteration was observed at the age of 24 months. Tubular cells developed senescence, which was detected by beta-galactosidase staining. This staining increased in frequency and intensity with age. Renal cortices showed a significant increase in the mRNA expression for TGF-beta1 and protein level for p21WAF1/CIP1. The enhanced expression of TGF-beta1 and p21WAF1/CIP1 was localized in the tubulointersititial cells. These data suggest that tubular cells undergo senescence and express increased TGF-beta1 and p21WAF1/CIP1 with advancing age. These age-related cellular and molecular alterations may play an important role in the initiation and/or progression of tubulointerstitial fibrosis and glomerulosclerosis in aging. 相似文献
100.
R G Jacob A P Shapiro P O'Hara S Portser A Kruger C Gatsonis Y Ding 《Psychosomatic medicine》1992,54(1):87-101
We determined the effect of relaxation therapy for hypertension in patients whose blood pressure remained elevated despite the use of antihypertensive medication. The effect was assessed in multiple settings, including the relaxation therapist's office, the Hypertension Clinic, and the patient's natural environment, the latter using 24-hour automated ambulatory blood pressure measures. Nineteen patients were randomized either to temperature biofeedback-assisted relaxation or to an attention control, "stress education." Antihypertensive medication was kept constant. In the behavioral therapist's office, blood pressure decreased in equivalent amounts with both treatments. Hypertension Clinic nurse blood pressure remained stable or increased with both treatments, but again there was no difference between treatments. Ambulatory blood pressure increased with relaxation therapy and decreased with stress education, the effect being significant for diastolic pressure. The effects on ambulatory blood pressure were limited to the waking hours. The only variable that showed superior effects for relaxation therapy was physician-determined blood pressure. These results call into question the generalizability of the effects of relaxation therapy from one setting to another. 相似文献