茶叶多糖的研究进展

茶叶多糖是一种复合杂多糖，具有许多生物活性。作者系统地介绍了茶叶多糖的提取、分离、纯化、纯度鉴定及相对分子质量测定的方法，以及其含量和组成、理化性质、化学结构及空间构象、生物活性等方面的研究进展，并对上述方法及研究进展进行了分析和评述。     

芪丹煎剂有效成分提取方法优选研究

目的:研究芪丹煎剂有效成分超声法提取的最适条件.方法:利用正交试验设计,对水量、提取时间和提取次数进行分析,找出最适条件.按最适条件重复3次,考察重复性.结果:水量为14倍、提取时间为30min,提取次数为3次时有效成分的总含量最大,3次平行试验有效成分总含量RSD为0.86%.结论:超声法提取的最佳条件为:水量14倍、提取时间30min,提取次数3次.本方法重复性较好.     

苯DNA加合物研究进展(综述)

苯ＤＮＡ加合物研究进展（综述）李桂兰，常平综述徐伯洪审校（中国预防医学科学院劳动卫生与职业病研究所，北京１０００５０）我国职业接触苯的工人约有５０万，长期接触苯可引起白血病。苯与其它实质性肿瘤的问题也有报道［１，２］。世界癌症研究机构（ＩＡＲＣ）１９...     

提高H2O2/甲酸体系选择性氧化抽提脱硫效率的研究

为了降低焦化蜡油(CGO)-甲酸／H2O2选择性氧化体系中H2O2的无效分解速度，屏蔽重金属离子对H2O2分解的催化效应，考察了造纸行业中常用的硅酸钠、硅酸镁和乙二胺四乙酸(EDTA)等稳定剂和螯合剂的加入对有机溶剂抽提后CGO中含硫量的影响。实验结果表明，EDTA可以很好地和重金属离子螯合，氧化后CGO抽余油中硫含量大幅降低。     

Supercritical fluids in medical radioisotope processing and chemistry,Part II: Applications – real and demonstrated

In Part I of this review series, an overview was presented on what the basic properties of supercritical fluids are and how they can, and are being used in many of today's industries as solvents for extraction, chromatography and reaction. A good part of this overview detailed the kinds of equipment needed, and techniques on how to use them for optimal performance. Part II of this series will delve into specific applications of supercritical fluid technology as it relates to aspects of medical isotope processing. The reader will note that very few applications of this technology to Nuclear Medicine have been published. Many potential applications cited within the context of this review derive from preliminary studies carried out in the author's laboratory. These examples are presented to spark interest in future developments of this nature. Copyright © 2003 John Wiley & Sons, Ltd.     

Guided bone regeneration for immediate non‐submerged implant placement using bioabsorbable materials in Beagle dogs

The aim of the present study was to evaluate the combined application of different bioabsorbable materials for healing of residual peri‐implant defects after placement of non‐submerged implants into fresh extraction sockets. Second and third mandibular premolars were extracted from 10 Beagle dogs, the coronal part of the distal sockets were surgically enlarged and this was followed by immediate placement of specially designed hollow‐screw non‐submerged dental implants. For each animal, the coronal peri‐implant defects were further treated with one of the 4 following procedures: 1) no treatment, control site: 2) grafting with porous hydroxyapatite (HA); 3) collagen membrane tightly secured around the implant and over the defect and 4) grafting with HA covered with a collagen membrane. After 16 weeks of healing, specimens were removed from the mandibule and prepared for a histomorphometric evaluation. The bone-to-implant contact length (BIC) was measured and compared amongst the different treatment modalities. In the defect area, the irregular bone regeneration was similar between all the treatment procedures ( P >0.10). In the sites covered with a collagen membrane alone, the total BIC (47%) was greater than in control sites (28.7%. P <0.05) or sites grafted with HA (22.2%, P <0.02). Total BIC in sites treated with the HA‐membrane combination (43%) was only significantly different from sites treated with HA ( P <0.10). It is concluded that the use of bioabsorbable materials results in a limited increase of osseointegration when used in conjunction with immediate placement of non-submerged implants, although the principle of the one stage surgical approach can be maintained.     

The behaviorally active peptide ACTH 4-10: Measurement in plasma and pharmacokinetics in man

Summary A specific radioimmunoassay for the quantitative measurement of ACTH 4-10 and a procedure for its extraction from plasma have been developed.Its pharmacokinetics was studied in eight healthy male volunteers given ACTH 4-10 125 µg/kg body weight as a bolus i.v. injection, by infusion and intranasally. Following the i.v. bolus, plasma levels rapidly declined biexponentially, with half-lives of 0.39±0.05 min for the -phase and 3.84 ± 1.5 min for the -phase (mean±SD). The constant rate i.v. infusion yielded steady-state levels between 0.74 and 5.06 ng/ml plasma. Administered as intranasal spray, absorption of intact ACTH 4-10 was low and variable (maximal bioavailability 7.6%).The results are discussed in relation to the dose-dependent effects of ACTH 4-10 on the auditory evoked potential.     

呼气相胸片的识别研究

根据呼气相胸片中肺部区域灰度较高的特点，通过边缘提取和边缘跟踪确定胸部区域，运用最大类间方差方法确定图像分割的阈值．再提取出肺部区域，然后求出肺部的灰度均值。但这样的结果并不理想。于是在此基础上提出修正方案，即以肺部灰度均值和骨骼灰度均值的比值作为特征值．即比例法。此方法可以较客观的识别呼气相胸片。最后用类间距离对这两种方法进行了量化比较。     

基于模糊连接度的多发性硬化症MR图像自动分割算法

多发性硬化症(MS)是一种严重威胁中枢神经功能的疾病,利用磁共振成像技术能够无损伤地检出其病灶。为了自动地对多发性硬化症病灶进行分割,提出了基于模糊连接度的分割算法,实现了种子点的自动选取。作为多发性硬化症分割的预处理,针对脑部MR FLAIR图像的特征,基于区域增长方法,还提出了脑部组织提取算法。通过对临床患者MR图像的分割实验,表明该分割算法能够比较准确地分割多发性硬化症病灶,其分割效果明显好于模糊C-均值聚类算法和基于马尔可夫场模型的分割算法。该算法还具有无监督、运算速度快、稳健性好等优点,能够应用于多发性硬化症的临床辅助诊断。