1,1,1,2—四氟乙烷—1,1—二氟乙烷二元系恒温汽液相平衡

采用静态蒸汽总压法实验装置，在２９．９４℃、３９．９２℃和４９．９３℃下，测定了１，１，１，２－四氟乙烷－１，１－二氟乙烷二元系汽液相平衡时的物料，总量、系统组成、蒸汽总压和汽相体积。结合物料衡算和Ｔ、Ｐ、ｘ推算ｙ的曲面样条函数法，计算出对应的平衡汽液相组成。用改进的ＰＲ状态方程和一个与温度无关的可调相互作用参数关联了实验数据。     

Evaluation of left ventricular contractile performance from baseline stress-shortening data in humans: comparison with pharmacological afterload challenge

The purpose of this study was to evaluate whether the baseline stress-shortening data reflect the contractile state adequately and give results comparable to the evaluation of the end-systolic stress-shortening relationships using pharmacological manipulation of afterload. Five groups were studied (total 152 patients): a control group of 30 healthy volunteers, 32 patients after surgical correction of infantile tetralogy of Fallot, 50 patients treated for childhood malignancies with doxorubicin, 17 patients with left ventricular hypertrophy due to systemic hypertension, and 23 patients with congestive cardiomyopathy. In all patients except those with congestive cardiomyopathy, afterload was altered pharmacologically to evaluate the individual stress-shortening relationship. In all patients the baseline stress-shortening data were evaluated, as well as their relative positions to two predefined normal ranges for the relationship between end-systolic stress and shortening. Additionally, a slope value was calculated from the baseline data of the five groups studied and compared with the data obtained by pharmacological afterload increment. Our data show that the comparison of individual baseline data of end-systolic wall stress and fractional shortening with predefined normal ranges for the relationship between end-systolic stress and shortening is inadequate. The appropriate normal range to compare with is the 95% confidence interval of baseline stress-shortening data in normal subjects. Also the calculation of a slope value from the baseline stress-shortening data of a group of patients seems to be inappropriate. Such a slope value does not necessarily reflect the contractile state, as the specific conditions leading to variations of end-systolic wall stress are undefined and not standardized, and the correlation between baseline stress-shortening data depends largely on the influence of the end-systolic dimension on both parameters.     

Photodynamic therapy of tumours: value of quantum chemical procedures for characterization of new drugs. Prediction of the electronic structure of zinc(II) phthalocyanine with special emphasis on triplet state excitation energies

Zinc(II) phthalocyanine is the active component of the liposomal formulation CGP 55847 which showed a high activity in photodynamic therapy in a variety of animal tumours. The photophysical properties of zinc(II) phthalocyanine have been studied in detail and compared to those of Photofrin, the only sensitizing agent approved so far for phase III/IV clinical trials. Since the efficacy of photodynamic therapy intrinsically depends on the spectroscopic features of the sensitizer, quantum chemical methods have proven to be an efficient means for optimizing chemical structures. As will be shown, a simple modification of the time-honoured INDO model of Pople allows a prediction of the singlet and triplet state properties of molecules of the size of zinc(II) phthalocyanine with an rms error of ≤ 1000 cm⁻¹.     

A preliminary study of stress symptoms and nutritional state in children

The aim of this work was to examine the occurrence of stressful events in the lives of children, using the ‘Scale of Infantile Social Readjustment’ (SISR), and the ‘Inventory of Symptoms of Infantile Stress’ (ISIS) to identify the presence of stress symptoms. The results of these evaluations were then used to examine the relationship between the levels of stress and the nutritional state of the children, by correlation. Forty 7–10‐year‐old children were included in the evaluation. From the analysed sample 49 per cent of them were eutrophic (weight/height normal to age), 50 per cent were above weight and 1 per cent was undernourished. Whereas 70 per cent of the girls were eutrophic and 30 per cent were above weight, only 35 per cent of the boys were eutrophic, 60 per cent were above weight and 5 per cent were undernourished. The results obtained in this first study indicated that 45 per cent of eutrophic girls demonstrated symptoms of stress, while 20 per cent of them were asymptomatic (with no symptoms of stress). Of the overweight boys, 30 per cent of them showed symptoms of stress and 35 per cent did not. This study indicated a possible relationship between weight and the symptoms of stress. Copyright © 2004 John Wiley & Sons, Ltd.     

Off-resonance effects in the transient response of SSFP sequences.

A previously developed eigenvector formalism is adapted to off-resonance in the transient response of quasiperiodic steady-state free precession (SSFP) sequences, including TrueFISP as a special case. The effective relaxation rates for essentially parallel and perpendicular deviations from the steady state are determined analytically in leading order perturbation theory. The latter are a known cause of oscillatory artifacts and therefore constitute the main target of a variety of preparation techniques. In addition, the former also play a dominating role in applications such as inversion recovery (IR) TrueFISP, which intentionally measure far away from the equilibrium. For both components, the approach toward equilibrium turns out to depend sensitively on field inhomogeneities, especially for smaller ratios of T2/T1. For the perpendicular deviations, the calculations show that--except very close to banding artifacts, where the steady-state signal is almost zero--field inhomogeneities additionally increase their effective relaxation rate almost as much as in the free induction decay (FID). The analytical results are tested against numerical simulation and MR measurements.     

View ordering for magnetization prepared steady state free precession acquisition: application in contrast-enhanced MR angiography.

Magnetization prepared segmented acquisition requires a view order that maximizes signal contrast during the acquisition of the central portion of k-space. Steady state free precession (SSFP) acquisition further requires a view order that minimizes changes in phase-encoding gradients from one repetition to the next in order to minimize eddy current artifacts. In this article, optimal view ordering schemes satisfying these two requirements are formulated and applied to inversion prepared 3D SSFP contrast-enhanced MR angiography (MRA). Experiments on phantoms and pigs demonstrated improved background suppression and reduced image artifacts.     

Steady state of gradient echo sequences with radiofrequency phase cycling: Analytical solution,contrast enhancement with partial spoiling

Spoiled gradient echo sequences can only reach a homogeneous steady state if sufficiently strong crusher gradients are used in combination with RF phase cycling (RF spoiling). However, the signal depends quite sensitively on the chosen phase increment ? and—lacking analytical solutions—numerical simulations must be used to study the transient and steady‐state magnetization. For the steady state an exact analytical solution is derived, which holds for arbitrary sequence and tissue parameters. Besides a considerably improved computation performance, the analytical approach enables a better understanding of the complicated dependence on ?. For short repetition times (TR) the regime of small ? turns out to be particularly interesting: It is shown that the typical ?_c, where RF spoiling starts to become effective, is essentially inversely proportional to T₂. This tissue dependence implies that contrasts can be considerably larger with partial spoiling (? ≈ ?_c) than with conventional RF spoiling (? ? ?_c). As an example, the uptake of contrast agents in tissues is investigated. For typical parameters a considerably improved contrast enhancement can be obtained, both theoretically and experimentally. Magn Reson Med, 2006. © 2005 Wiley‐Liss, Inc.     

深圳市龙岗区坪地外来工亚健康状态的研究

目的 :探讨深圳市龙岗区坪地外来工亚健康状况及其影响因素 ,为预防亚健康提供科学依据。方法 :采用统一表格对 12 68深圳市龙岗区坪地外来工进行调查。结果 :外来工的平均年龄为 ( 2 4.96± 6.10 )a ,其亚健康状态总体发生率为 65 .3 0 %,男性亚健康状态发生率为 63 .2 1%,女性为 67.91%,男性和女性之间差异无统计学意义。亚健康状态主要影响因素为 :结婚与否、睡眠时间、工作时间、加班时间以及工作是否有压力和居住环境差等因素 ,而与吸烟、饮酒、文化程度等因素无相关。结论 :深圳龙岗区坪地外来工中普遍存在亚健康状态 ,其发生较高且与工作环境、工作时间、加班时间有密切关系 ,故应引起政府部门及社会各界高度重视 ,加强对外来工的健康保护     

The Impact of Exacerbations on the Asthmatic Patient's Preference Scores

The purpose of this study was to examine the effect of exacerbations on mild to moderate asthmatic patients' preference-based, health-related, quality of life scores and also to describe the effect of these exacerbations on daily life. In a survey, 100 mild to moderate asthmatic patients in the United Kingdom were asked to rate three different health marker states on a scale between 0 (death) and 100 (perfect health), defined as: your asthma of today, a mild exacerbation, and a severe exacerbation of asthma. They were also asked to describe their symptoms and what they did when experiencing an exacerbation. During exacerbations the vast majority of asthmatic patients have significant symptoms and consume a considerable amount of health care resources, which often overlap. The health marker state “your asthma of today” was given a mean score of 81.0, a mild exacerbation a score of 62.1, and a severe exacerbation a score of 25.6, indicating a large impact on patients' daily life and their health-related quality of life. In conclusion, asthmatic patients are severely affected in their health and daily living by mild and severe exacerbations. Considerable effort should be made to reduce the number and severity of exacerbations.     

EVOKED POTENTIALS OF OBSESSIVE-COMPULSIVE DISORDER： STATE OR TRAIT MARKER

Objective To investigate the status of evoked potentials in obsessive-compulsive disorder(OCD). Methods Evoked potentials P300, auditory brainstem response (ABR) and visual evoked potential ( VEP) were recorded from 35 OCD patients and 28 normal controls (NC) with a Nicolet Spirit Instrument. 23 of the OCD patients were followed up after 5 months with the same markers. Results Compared with NC, OCD patients showed decreased P3 of P300 amplitude (OCD group 3. 5 ±1. 6μv vs. NC group 5.9 ±2. 1μv, P <0. 01), delayed V latency (6.4±0. 4ms vs. 5. 5 ±0. 3ms, P <0. 01) and increased V amplitude(0. 35±0. 1μv vs. 0. 16 ±0.09μv, P <0. 05) of ABR and delayed P2 of VEP latency (199±39ms vs. 183±28ms, P <0. 05). The follow-up measures of evoked potentials suggested that decreased P3 of P300 amplitude and delayed P2 of VEP latency might be state markers of OCD, while decreased V amplitude and delayed V of ABR latency might be trait markers of OCD. Conclusion The changes of P300 and VEP are related to clini