指数程序升温药物稳定性试验

介绍了一种新的程序升温(指数程序升温)药物稳定性预测加速试验方法及计算方法。在这一新的程序升温方法中,温度每升高10℃,升温速率将增大2～4倍:dT/dt=a^(T-T₀)/10·(dT/dt)₀,使药物在高温和低温范围内的降解程度尽可能一致,提高了试验准确度。采用单因素优选法和数值积分法处理试验数据,避免了任何近似处理,使计算结果准确可靠。与线性升温、倒数升温和对数升温加速试验进行了对比,结果表明,指数程序升温法的准确性优于其它3种升温法。     

Relationship of Psychosocial Risk Factors, Certain Personality Traits and Myocardial Infarction in Indians: A Case�Ccontrol Study

Objective:

To investigate the relationship of psychosocial factors (lack of social support, stress and subjective well-being) and personality traits with myocardial infarction (MI).

Materials and Methods:

A case–control study involving 100 cases and 100 matched controls was conducted in Lok Nayak Hospital, New Delhi.

Results:

Stress over 1 year was significantly higher in cases (P < 0.001). However, difference was not significant when scores of social support (P = 0.2), Presumptive Stressful Life Event (PSLE) over lifetime (P = 0.058) and subjective well-being (P = 0.987) were compared. MI was significantly associated with hyperactive (P < 0.001), dominant (P = 0.03), egoistic (P < 0.001) and introvert (P < 0.001) personalities.

Conclusion:

Certain personality traits and recent stress may be important risk factors of MI, especially in Indians. The finding may have implications on the preventive strategies planned for MI patients.     

漫反射光谱法研究维生素C与片剂辅料的相互作用

漫反射是一束光射到一定厚度的不透明不光滑固体表面上,光被部分吸收和部分散射后,向各个方向的反射。反射光的分数称为反射率。测定反射率时一般与某种白色粉末(例如硫酸钡)相比较,测得的反射率为相对反射率。以相对反射率对波长作图所得的曲线称为漫反射光     

Blood flow imaging with MR: spin-phase phenomena

Blood flow phenomena occurring when flow is within the magnetic resonance (MR) imaging plane were analyzed. In this situation, the signal intensity of vascular lumina is predominantly determined by spin-phase change phenomena, and section transition effects of moving spins can be neglected. In this paper, we develop the concepts of in-plane flow, with emphasis on the notion that the spatial variations in velocity and acceleration of blood, which mainly occur along vessel walls, are important determinants of intravascular signal loss in MR images. Flow patterns in the large mediastinal arteries were qualitatively and quantitatively analyzed in six healthy subjects and 14 patients with hemodynamic abnormalities using multiple electrocardiograph-gated image acquisition; ungated studies of 30 patients were analyzed for venous flow effects. Intraluminal signal was strongly dependent on the phase of the cardiac cycle and the echo number. Signal loss was found to occur along vessel walls, in vascular bends, and at bifurcations.     

Use of pulse oximetry for blood pressure measurement after cardiac surgery

Blood pressure measurement using pulse oximeter waveform change was compared with an oscillometric measurement and the gold standard, intra-arterial measurement, in children after cardiac surgery. Forty six patients were enrolled and divided into groups according to weight. Simultaneous blood pressure measurements were obtained from the arterial catheter, the oscillometric device, and the pulse oximeter. Pulse oximeter measurements were obtained with a blood pressure cuff proximal to the oximeter probe. The blood pressure measurements from the pulse oximeter method correlated better with intra-arterial measurements than those from the oscillometric device (0.77-0.96 v 0.42-0.83). The absolute differences between the pulse oximeter and intra-arterial measurements were significantly smaller than between the oscillometric and intra-arterial measurements in children less than 15.0 kg. The pulse oximeter waveform change is an accurate and reliable way to measure blood pressure in children non-invasively, and is superior to the oscillometric method for small patients.     

A contrast correction method for dental images based on histogram registration

Contrast correction is often required in digital subtraction radiography when comparing medical data acquired over different time periods owing to dissimilarities in the acquisition process. This paper focuses on dental radiographs and introduces a novel approach for correcting the contrast in dental image pairs.The proposed method modifies the subject images by applying typical registration techniques on their histograms. The proposed histogram registration method reshapes the histograms of the two subject images in such a way that these images are matched in terms of their contrast deviation. The method was extensively tested over 4 sets of dental images, consisting of 72 registered dental image pairs with unknown contrast differences as well as 20 dental pairs with known contrast differences. The proposed method was directly compared against the well-known histogram-based contrast correction method.The two methods were qualitatively and quantitatively evaluated for all 92 available dental image pairs. The two methods were compared in terms of the contrast root mean square difference between the reference image and the corrected image in each case. The obtained results were also verified statistically using appropriate t-tests in each set.The proposed method exhibited superior performance compared with the well-established method, in terms of the contrast root mean square difference between the reference and the corrected images. After suitable statistical analysis, it was deduced that the performance advantage of the proposed approach was statistically significant.