Identification of the three-element windkessel model incorporating a pressure-dependent compliance

A new one-step computational procedure is presented for estimating the parameters of the nonlinear three-element windkessel model of the arterial system incorporating a pressure-dependent compliance. The data required are pulsatile aortic pressure and flow. The basic assumptions are a steadystate periodic regime and a purely elastic compliant element. By stating two conditions, zero mean flow and zero mean power in the compliant element, peripheral and characteristic resistances are determined through simple closed form formulas as functions of mean values of the square of aortic pressure, the square of aortic flow, and the product of aortic pressure with aortic flow. The pressure across as well as the flow through the compliant element can be then obtained so allowing the calculation of volume variation and compliance as functions of pressure. The feasibility of this method is studied by applying it to both simulated and experimental data relative to different circulatory conditions and comparing the results with those obtained by an iterative parameter optimization algorithm and with the actual values when available. The conclusion is that the proposed method appears to be effective in identifying the three-element windkessel even in the case of nonlinear compliance.     

低收入大学生一般自我效能感、主观幸福感研究

近年来 ,低收入大学生作为高校中的一个特殊群体逐渐受到研究者和教育者的关注。目前对低收入大学生的一般自我效能感 (generalself -efficacy)和主观幸福感的研究还不多见。一般自我效能感是指个体对各种挑战或新情境的应对能力的总体信心[1] 。一般自我效能感描述的是个体有效地应对各种紧张情境的广义而稳定的个人能力感 ,它与身心健康存在一定的关系[1- 2 ] 。主观幸福感 (subjectivewell-being)是指人们对于自己是否幸福的主观感受 ,是反应心理健康水平的重要指标之一。研究低收入大学生的一般自我效能感和幸福感的特点及其关系对于揭…     

儿童退缩和同伴关系的相关

目的：用元分析方法对近20年关于儿童退缩和同伴关系相关的研究结果进行总结。方法：用多水平分析技术对儿童退缩和同伴接受的相关、退缩和同伴拒绝相关的研究结果进行总结分析。结果：儿童退缩和同伴接受之间有显著的负相关关系，退缩和同伴拒绝之间有低度的非负相关关系，各研究结果之间的变异显著。结论：退缩导致儿童不良的同伴关系。     

Contraluminal transport of organic cations in the proximal tubule of the rat kidney

In order to study the quantitative structure/activity relationship of organic cation transport across the contraluminal side of the proximal renal tubule cell, the stopped-flow capillary microperfusion method was applied and the inhibitory potency (apparent K _i values) of different homologous series of substrates against N ¹-[³H]methylnicotinamide (NMeN⁺) transport was evaluated. Aniline and its ring- or N-substituted analogues as well as the aminonaphthalines do not interact with the contraluminal NMeN⁺ transporter except for the quaternary trimethylphenylammonium and pararosaniline, which bear a permanent positive charge, and for 1,8-bis-(dimethylamino)naphthaline, which forms an intramolecular hydrogen bond. If, however, one or more than one methylene group is interposed between the benzene ring and the amino group, the compounds interact with the contraluminal NMeN⁺ transporter in proportion to their hydrophobicity parameter, i.e. the octanol/water partition coefficient (log octanol). The catecholamines and other hydroxyl-substituted phenylethyl analogues also follow this rule. In addition, the N-heterocyclic pyridine, quinoline, isoquinoline and acridine analogues also interact with the contraluminal NMeN⁺ transporter, when their pK _a values are higher than 5.0, and, an inverse correlation between pK _a and log K _{i, NMeN} was observed. An exception to this rule are those hydroxy compounds of pyridine, quinoline and isoquinoline that show tautomerism. These compounds slightly inhibit NMeN⁺ transport despite low pK _a values. The quaternary nitrogen compounds of aniline and the N-heterocyclic analogues, as far as tested, all interact with the contraluminal NMeN⁺ transporter in relation to their hydrophobicity. The data indicate that the contraluminal NMeN⁺ transporter interacts with N-compounds according to their hydrophobicity and/or according to their basicity (affinity to protons). The reason for deviation of the aniline analogues and the OH-tautomeric heterocyclic N-compounds from this behaviour is discussed.     

Relationship quality moderates the effect of social support given by close friends on cardiovascular reactivity in women

We examined the role of the type of support provided, gender of support provider, and relationship quality in predicting how social support might influence cardiovascular reactivity during acute stress in women. A group of 88 women received either emotional, instrumental, or no support from a close female or male friend while performing a series of speech tasks. Results suggest that the effectiveness of social support for women depended primarily on the quality of the friendship (i.e., purely positive, or ambivalent). More specifically, women who interacted with a female, ambivalent friend had the largest changes in diastolic blood pressure, total peripheral resistance (TPR), and pre-ejection period compared to the other conditions. Furthermore, receiving emotional support from a purely positive friend was related to lower increases in cardiac output (CO) compared to a no-support condition. In contrast, receiving emotional support from an ambivalent friend was related to larger increases in CO and only small changes in TPR when compared to individuals in the no-support condition. These data are discussed in light of the psychosocial processes underlying social support effects in women, and the importance of a more comprehensive view of how close relationships influence cardiovascular function. This research was generously supported by Grant1 R01 MH58690-01 from the National Institute of Mental Health awarded to Bert N. Uchino.     

Relationship between frequency and amplitude of myocardial contractions in rats adapted to heat

After preliminary adaptation of rats to heat (for 3 h daily at 35°C for 1 month) the amplitude of contractions of the isolated papillary muscles from the left ventricle at 28°C at high frequency was higher than in control animals. This difference persisted at 36°C and disappeared at 25°C. It is postulated that adaptation to heat leaves a definite structural imprint in heart muscle cells.Laboratory of Pathophysiology of the Heart, Institute of General Pathology and Pathological Physiology, Academy of Medical Sciences of the USSR, Moscow. Institute of Physiology and Experimental Pathology of the Arid Zone, Academy of Sciences of the Turkmenian USSR, Ashkhabad. (Presented by Academician of the Academy of Medical Sciences of the USSR A. M. Chernukh.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 82, No. 10, pp. 1168–1170, October, 1976.     

精神分裂症恢复期患者及家属家庭干预的对照研究

目的：以康复期出院精神分裂症患者和家属为对象，定期复诊进行家庭干预并对照研究。方法：干预组68例，对照组52例，采用BPRS评定；干预组家属74人，对照组家属65人，采用SCL－90评定。结果：6个月后干预组患者BPRS和入组时对照比较均有显著性差异（P＜0．01），说明干预组患者的精神症状，不良情绪及社会功能明显好转，入组时两组家属SCL－90评定与常模对照比较，均有明显差异（P＜0．05或0．01），经干预后干预组与全国常规比较无显著性差异（P＞0．05），说明患者家属普遍存在心理障碍，经干预后家属心理状况明显改善。结论：对康复期病人及家属进行门诊家庭干预，是有效的康复方法，值得推广应用。     

优化原理与小动脉血流量─管径关系

作者假设血液为符合幂定律的非牛顿流体，对小动脉血管系统进行了详细的优化分析。导出了血流量与管径立方成正比的结论以及壁面切变率与管径无关的推论。此结果既包含了前人对于牛顿血流的研究成果，又能克服后者的不足，而与近期的生理测定一致。     

The categorical and dimensional models of endogenous depression

We calculated a Research Diagnostic Criteria (RDC) endogenous score for 257 depressed inpatients based on the number of endogenous criteria present. The distribution of RDC endogenous scores was unimodal. There was no association between endogenous scores and results of the Dexamethasone Suppression Test, or morbid risk for depression in the patients' first-degree relatives. The morbid risk for a family history of alcoholism tended to decrease with increasing endogenous scores, although a consistent steady decline was not observed. The results suggest that the RDC criteria do not fit either the categorical or dimensional model of endogenous classification. Potential sources of difficulty with the RDC endogenous criteria are discussed.     

The parent-physician relationship in pediatric asthma care

OBJECTIVE: To examine the feasibility of using a behavioral coding system, the Five Minute Speech Sample (FMSS), to estimate the prevalence of relationship difficulties between parents and physicians in a pediatric asthma care setting. METHOD: The FMSS was administered to 20 parents of children with severe, chronic asthma and to the physicians they worked with during a brief day program admission. RESULTS: Rates of relationship difficulties between parents and physicians ranged from 15% to 40%, comparable to those previously identified in patient-therapist relationships in psychiatric populations. CONCLUSIONS: Although further information is needed about validity and reliability, the FMSS appears to provide clinically relevant information about the parent-physician relationship in the context of pediatric chronic illness.