Development and experimental in vivo validation of mathematical modeling of laser coagulation

Most clinical procedures using the laser are based on thermal laser-tissue interactions. The treatment often consists of inducing damage of given degree and extent by heating the tissue. The aim of this study was to develop a model called HELIOS. The ability of HELIOS to predict thermal coagulation was evaluated by comparison with in vivo experimental results. Conversion of laser light in tissue was studied using the beam-broadening model. Temperature was described by the heat conduction equation solved using the finite difference method. The tissue dena-turation was modeled by the Henriques equation leading to the determination of the damage coefficient ω. For a given set of laser and tissue parameters, HELIOS makes a graphic representation of coagulation necrosis and temperature evolution in tissue. HELIOS was validated by experimental studies in vivo on rat liver using a CW Nd:YAG laser, a CO₂ laser, and an argon laser. For given sets of laser parameters, temperature measurements were performed using an infrared camera. Histological examinations were carried out on samples to quantify the depth of coagulation necrosis. Experimental data obtained in vivo were compared with those calculated using HELIOS and similar sets of parameters. The difference between the predicted temperature evolution on tissue surface and that measured by the infrared camera was < 5°C in all cases. The difference between the predicted coagulation necrosis depth and the corresponding experimental one was < 10%. In conclusion, HELIOS allows good prediction of tissue temperature and coagulation necrosis. © 1994 Wiley-Liss, inc.     

中国高等教育评估制度探析

高等教育大众化对质量的关注是必然的.高等教育评估制度的建设是当前我国深化高等教育管理体制改革、保证高等教育健康发展的需要.我们要建立既符合中国国情又体现高等教育评估普遍规律的具中国特色的高等教育评估制度.     

去骨瓣减压术治疗大面积脑梗死的短期疗效评价

目的:评价去骨瓣减压术治疗大面积脑梗死的效果。方法:制定入选和排除标准,统一术式,比较术前、术后不同时期的神经功能变化,并对存活病例进行随访(6个月),评价术后3和6个月时的预后评分(GOS)和BarthelIndex(BI)的变化。结果:按入选标准行去骨瓣减压术26例,术后死亡率为30.8%。术前昏迷评分GCS对决定手术时机有指导作用。共随访14例患者,术后3和6个月GOS分别为3.6±0.8和4.0±0.8,与出院时GOS评分比差异有统计学意义。术后3和6个月BI分别为68.9±29.4和77.5±28.3,其中术后6个月BI>60者占85.7%。结论:对保守治疗无效的大面积脑梗死患者,去骨瓣减压术不仅可作为一种“救命”手术,而且多数存活病例恢复较好。合理选择手术适应证、及时把握手术时机以及充分手术减压可能是影响预后的重要因素。     

主成份分析与因子分析用于多指标综合评价

本文从应用角度阐明了主成份分析与因子分析用于多指标综合评价的异同点，并用实例加以说明。提出了主成份分析和因子分析用于多指标综合评价时，应在能明确主成份或因子的意义和方向情况下加权，否则会得到错误的结果。     

Anticonvulsant Activities of 4–Bromobenzaldehyde Semicarbazone

Summary: Some of the properties of 4–bromobenzalde-hyde semicarbazone (compound IV), a prototype molecule of a new class of anticonvulsants, aryl semicarbazones, are described. Compound IV demonstrated activity in the maximal electroshock (MES) and subcutaneous pentylenetetrazol (scPTZ) tests in mice, with low neurotoxicity. When given orally to rats, it displayed high potency in the MES test and very low neurotoxicity, resulting in a high protective index (PI). Compound IV displayed no proconvulsant properties, and development of rapid tolerance was not noted. When administered intraperitoneally (i.p.) at doses of 100, 300, or 600 mg/kg to rats, compound IV had no effect on levels of γ-aminobu-tyric acid (GABA) or on GABA-T activity in whole brain. When tested in vitro, compound IV had no effect on rat brain GABA-T at a drug concentration of 100 μM. Although the activities of certain drug-metabolizing enzymes were increased after oral administration of compound IV to rats, these effects were less prominent than those of phenytoin (PHT) and carbamazepine (CBZ). The principal mode of action of compound IV does not appear to be an interaction with the GABA_A receptor complex, and other mechanisms, involving excitatory amino acid neurotransmission, will have to be considered in future investigations of the anticonvulsant activity of this compound.     

Monitoring of skin response to sodium lauryl sulphate: clinical scores versus bioengineering methods

The present trial was designed to evaluate clinical scores (single observer) of sodium lauryl sulphate (SLS)-induced skin irritation in a group of subjects (n = 10) over a 10-day period along with various skin function parameters. In order to avoid significant variations due to secondary phenomena, the following parameters were recorded with non-invasive instruments in this order: skin capacitance (C1; arbitrary units; CM420 Corneometer), transepidermal water loss (TEWL; g/m2.h; Evaporimeter) and laser Doppler flowmetry (CBFV: cutaneous blood flow values; Periflux). All examinations were performed during winter on reclined relaxed subjects present for at least 10 min in a test room with controlled temperature and relative humidity (t degrees: 19.5-20.7 degrees C and RH: 47.3-60.3%). The analysis of differential data (delta = value at tx-value before test; 2-way ANOVA) was made on single parameters as a function of site (volar forearm versus neck) and time (from 24 h after 48-h occlusion with 5% SLS up to 10 days later). The profile of erythema scores over time differed between neck and forearm, but the delta CBFV readings with the laser Doppler instrument did not detect significant site-time interactions. Roughness (blind evaluation with palpating finger) and capacitance readings (delta C1) showed significant differences between sites, but the profile over time was similar in both locations. delta TEWL did not differ according to anatomical location. The reason for different erythema scores on neck and forearm might be related to inherent regional variation of optical properties of the skin or to a substantial contribution of SLS-induced roughness to the readings of erythema.(ABSTRACT TRUNCATED AT 250 WORDS)     

抗衰老药物家蚕寿命测定法的研究

本实验表明，多种中药材，如香附子、花粉、党参、菟丝子、蛇床子等的提取液涂在桑叶上喂蚕，能显著延长蚕蛾寿命，但对家蚕幼虫龄期无明显影响。这种实验方法重演性好，如能进一步完善试验方法，将可用于筛选抗衰老药物的研究。     

三种虾蛄肌肉营养成分分析及评价

虾蛄俗称“虾爬子”,“螳螂虾”,“琵琶虾”、“小龙虾”等 ,隶属节肢动物门 ,甲壳纲 ,口足目 ,虾蛄科的经济海产动物 ,主要生活在近海浅滩泥质海底巢穴中 ,全国各地的沿海都有分布。近年来随着人们膳食结构的转变 ,虾蛄是深受人们喜爱的佳肴 ,也是出口创汇的水产品之一。对虾蛄 ,国内外均有研究 [1～ 6 ]。但对营养成分分析报道较少[7,8] 。本研究分别对三种虾蛄的基本营养成分、氨基酸、脂肪酸的组成和含量进行比较研究 ,为虾蛄的人工养殖和综合利用提供基础数据。1　材　料　与　方　法1 .1　材料　　实验所用口虾蛄 ( Oratosquilla ora…     

肺部三种疾病模糊数学鉴别诊断的探讨

本文对肺部三种疾病１５３６例患者的病历资料，按病种作了统计归类。运用模糊数学原理建立了征候一疾病间的模糊关系矩阵，用参量加权模糊综合评判模型，对肺部三种疾病鉴别诊断的符合率达８２．９１％以上，因此认为文中建立的模型，对肺部三种疾病鉴别诊断具有参考价值。     

ROOT ZX根管长度测量仪临床应用评价

目的 评价森田ROOT ZX根管长度测量仪临床应用价值.方法 用根管长度测量仪对108例根管进行根管测量,以此长度进行根管预备后,按测量长度插入牙胶尖摄X线牙片,计算出实际根管长度,求得测量准确率.结果 ROOT ZX测量准确率为92.6%.结论 ROOT ZX根管长度测量仪应用安全可靠、准确率高.