评“McCall观察方法”——对一种色谱系统分配效果观察方法的商榷

本文通过理论分析和文献数据的分析,对McCall提出的色谱系统分配效果的观察方法提出了不同的看法,认为McCall方法中的所谓logK并不是常数。McCall的方法无论在理论上和实践上都是不妥的。     

中老年男性血糖与血清脂质及载脂蛋白的关系

目的　研究血糖水平与脂质及载脂蛋白水平的关系。方法　对成都地区 735例 40～ 70岁男性空腹 12～ 14小时的血糖、血清甘油三酯 (TG)、胆固醇 (TC)、高密度脂蛋白胆固醇 (HDL- C)、低密度脂蛋白胆固醇(L DL- C)和血清载脂蛋白 (apo) A 、A 、B10 0、C 、C 及 E含量进行了测定。依空腹血糖的水平将受试对象分为正常组 (S1)、糖耐量减退组 (S2 )、糖尿病组 (S3)。结果　结果显示 :S2和 S3的高脂血症发病率比 S1高 (分别为64.5 %、45 .2 %和 32 .1% ) ;空腹 TG水平 S2 (3.62± 2 .5 2 mm ol/ L)和 S3(4 .45± 3.82 mmol/ L)均显著高于 S1(1.92± 1.93m mol/ L) ,P均 <0 .0 1;TC水平 S2 (5 .68± 1.15 mmol/ L)和 S3(5 .68± 1.12 m mol/ L)亦显著高于 S1(5 .13±1.0 6m mol/ L) ,P均 <0 .0 5 ;S2和 S3的血清 apo B10 0、C 、C 及 E水平显著高于 S1(P均 <0 .0 1或 P<0 .0 5 )。相关分析表明 ,血糖与血清 TG在 S1、S2和 S3中均呈显著正相关 (r分别为 0 .180 0、0 .1436和 0 .32 12 ) ,P均 <0 .0 0 1;而在 S2和 S3中血糖与 HDL- C呈负相关 (r分别为 - 0 .2 5 34和 - 0 .1477) ,P均 <0 .0 0 1;在 S1、S2、S3组中血糖与血清 apo B10 0、C 及 E呈正相关 (P均 <0 .0 0 1) ,与 apo C 则在 S1和 S2中呈正相关 (P<0     

On the secondary stability of coated cementless hip replacement: parameters that affected interface strength

Unlike primary stability of coated cementless implants, their secondary stability has been poorly studied. This paper considers some theoretical aspects of the secondary stability of a coated cementless hip implant in a human femur. The bone is separated from the implant by a thin layer of microscopic peaks and troughs formed on the surface of the coating. The size of the peaks and troughs is very small compared with the macrosize of the implant stem and bone in contact. The study of the bone–stem contact by direct application of the finite element method is prohibitively costly. A two-scale asymptotic homogenisation procedure that takes into account the microgeometry of the interface layer and mechanical properties of bone and the implant material is applied to obtain effective, homogenised contact parameters. These parameters can be used in finite element analyses involving smooth interfaces, which require hundreds of times fewer finite elements. With the homogenisation technique and finite element analyses for a simplified design, two parameters were found to be most important—the normal contact stiffness and the friction coefficient. They both increase several times as bone grows into the rough surface of the implant and mineralises, thus providing a stronger interface and resulting in reduced micromotions.     

Natural frequency/damping coefficient relationship of the catheter-manometer system required for high-fidelity measurement of the pulmonary arterial pressure

Using a digital simulation method, we analyzed the relationship between natural frequency (f _n ) and damping coefficient () of the catheter-manometer system required for high-fidelity measurement of the pulmonary arterial pressure. The pulmonary artery pressure waveform was obtained with a catheter-tip transducer and it was fed into a dynamic simulator programmed on a computer. The original waveform and the output of the simulator were compared and judged visually for the fidelity. From this analysis, the combination of f _n and was obtained and was plotted on a f _n – diagram. It showed as an area, which was convex on the left side and open on the right side. The left-convex endpoint was located at a damping coefficient of about 0.7. At a lower heart rate, this area was extended to the lower frequency side, while, at a higher heart rate, this area was limited to the higher frequency side. The f _n – diagram was also constructed theoretically by calculating the relations between natural frequencies and damping coefficients of a second order system with the amplitude and phase error tolerance set at +/–5% respectively.(Kinefuchi Y, Suzuki T, Takiguchi M, et al.: Natural frequency/Damping coefficient relationship of the catheter-manometer system required for high-fidelity measurement of the pulmonary arterial pressure. J Anesth 7: 419--426, 1993)     

人工股骨头置换术的应用解剖

目的:为临床人工股骨头置换术人工假体的选择、安装及定位提供可靠的解剖学参数。方法:对250例(左右各125例)正常成人股骨头、股骨颈、大转子与外上髁间距进行观测,并得出转子髁间距与股骨头最大径、股骨头颈前长和股骨头颈后长的相关系数和回归方程。结果:股骨头最大径为4.39±0.31cm,股骨头颈后长为6.89±0.49cm,股骨头颈前长为6.18±0.43cm,大转子与外上髁间距为34.40±1.79cm。结论:采用本文作者提供的方法选择、安装人工假体准确、实用、方便     

Morphological and functional demonstration of rat dura mater mast cell-neuron interactions in vitro and in vivo

The effects of changes in temperature on primary and secondary endings of isolated cat muscle spindles were investigated under ramp-and-hold stretches and different degrees of pre-stretch. Temperature-induced alterations of the discharge frequency were compared over a temperature range of 25–35°C. Both primary and secondary endings responded to warming with increasing discharge frequencies when the spindle was pre-stretched by 5–10% of its in situ length. The following differences between the temperature effects on primary and secondary endings were observed: (1) The temperature coefficients (Q₁₀) obtained from the discharge frequencies during the dynamic and static phase of a stretch were similar for endings of the same type, but they were larger in primary endings (range of Q₁₀: 2.3–3.3; mean: 2.9) than in secondary endings (range of Q₁₀: 1.6–2.2; mean: 2.0); (2) With primary endings, but not with secondary endings, the temperature sensitivity (imp s⁻¹ °C⁻¹) was larger during the dynamic phase than during the static phase of a stretch; (3) In primary endings, the fast and slow adaptive components occurring in the discharge frequency during the static phase of a stretch clearly increased with warming while in secondary endings, the slow decay was less affected, and the fast decay showed no change; (4) In relaxed spindles, the excitatory effect of warming was overlaid by a strong inhibitory effect as soon as the temperature exceeded about 30°C, resulting in an abrupt cessation of the background activity in most secondary endings, but not usually in primary endings. In general, warming induced an enhanced stretch sensitivity in both types of ending, and additionally an inhibitory effect that is obvious only in secondary endings of relaxed spindles. The different effects of temperature on the discharge frequency of primary and secondary afferents are assumed to be caused by different properties of their sensory membranes.     

Amino Acid Side-Chain Contributions to Free Energy of Transfer of Tripeptides from Water to Octanol

The location of amino acids in soluble or membrane proteins is related to the hydrophobicity of the side chains. Amino acid hydrophobicity values are based upon the thermodynamics of transfer from an aqueous to a nonaqueous environment. However, for certain hydrophilic residues uncertainty exists on the appropriate hydrophobicity values. We have measured the octanol- water partition coefficients (P _o/w) of tripeptides of the sequence N-14-C-acetyl-Ala-JT-Ala-NH-tButyl (AcAlaXAlaNHtButyl), where the central residue X was either Gly , Ala, Phe, Trp, Pro, His, Asp, or Glu. The P _o/w for the tripeptides agreed reasonably well with values calculated by the fragment method of D. J. Abraham and A. J. Leo (Proteins Struct. Func. Gen. 2, 130–152, 1987). The log P _o/w of the uncharged form was 1.6,2.7, and 2.5 greater than the log P _o/w of the ionized form for the His, Asp, and Glu peptide, respectively. The new data on the pH dependence of the ionizable side chains, His, Asp, and Glu, should result in better prediction of the partition coefficient of peptides as a function of pH. The thermodynamic parameters were determined from the temperature dependence of partitioning. In the temperature range studied (2 to 65°C) the transfer of tripeptides from water to octanol was entropy governed except for the ionized peptides. A heat capacity term was necessary to account for the transfer of tripeptides containing non polar residues. The heat capacity change for transfer from water into octanol was –45, –73, –81, and –88 cal/mol K for Ala, Phe, Trp, and Pro peptides, respectively. Peptides containing Gly, His (pH 7.2), and the uncharged forms of Asp, Glu, and His did not show a significant change in heat capacity. The side-chain contribution of the central residue X (G _X) to the free energy of transfer was obtained from the difference between the free energy o f transfer of the peptide containing the central residue X and the Gly peptide; G _X = G _{(AcAlaGlyAlaNHtButyl)} - G _{(AcAlaGlyAlaNHtButyl)}. The relative order of hydrophobicity of the side chains correlated well with previous studies. However, a significant difference was found for the absolute hydrophobicity between the present study and experimental data on N-acetyl amino acid amide derivatives (J. Fauchere and V. Pliska, Eur. J. Med. Chem. 18(4), 369–375, 1983). The G _X values at pH 7.2 were 0, –0.13, –2.19, –2.52,–0.29, –0.16, 3.50, and 3.12 kcal/mol for Gly, Ala, Phe, Trp, Pro, His, Asp, and Glu, respectively. These hydrophobicity values in a tripeptide environment provide suggested values for a hydrophobicity scale.     

大学生社交焦虑与班集体人际关系的调查研究

目的了解大学生社交焦虑和班集体人际关系现状,为高校心理健康保健提供确实的依据。方法对重庆市3所大学共5个班进行交往焦虑量表和大学班级集体人际关系问卷调查。结果农村大学生的社交焦虑高于城镇大学生;男生的负向人缘系数高于女生;非独生子女大学生的负向人缘系数高于独生子女大学生;大学生社交焦虑与负向人缘系数呈显著负相关,大学生的自我认知和自我体验与实际的人际关系并不完全一致。结论大学生社交焦虑与负向人缘系数呈显著负相关。     

室性早搏的快速检测方法

提出一种利用相关性和RR间期比相结合的快速室性早搏的检测算法.该算法具有一定的病人自适应性.通过MIT-BIH心律失常数据库的验证,该方法对Normal和PVC有很高的识别率.