RASER: a new ultrafast magnetic resonance imaging method.

A new MRI method is described to acquire a T(2)-weighted image from a single slice in a single shot. The technique is based on rapid acquisition by sequential excitation and refocusing (RASER). RASER avoids relaxation-related blurring because the magnetization is sequentially refocused in a manner that effectively creates a series of spin echoes with a constant echo time. RASER uses the quadratic phase produced by a frequency-swept chirp pulse to time-encode one dimension of the image. In another implementation the pulse can be used to excite multiple slices with phase-encoding and frequency-encoding in the other two dimensions. The RASER imaging sequence is presented along with single-shot and multislice images, and is compared to conventional spin-echo and echo-planar imaging sequences. A theoretical and empirical analysis of the spatial resolution is presented, and factors in choosing the spatial resolution for different applications are discussed. RASER produces high-quality single-shot images that are expected to be advantageous for a wide range of applications.     

A simplified statistical method for local INR using linear regression

A simplified method of International Normalized Ratio (INR) derivation using linear regression of certified INR plotted against local prothrombin time (PT) results has been compared with INR from conventional orthogonal regression. Linear regression assumes error only with the local PT results whereas orthogonal regression assumes error with both reference and local results. The reliability of local INR derivation using lyophilized plasmas has been assessed in a collaborative study. INR from conventional fresh plasma International Sensitivity Index (ISI) calibrations have been compared with INR from calibrations with two types of lyophilized plasma, artificially depleted and coumarin.
Although calibration slopes differed with the two types of analysis and the different lyophilized plasmas, both gave reasonable approximations to fresh plasma ISI calibrations. With orthogonal regression the overall percentage INR deviation was 5.25% with the artificially depleted plasmas and 6.85% for the results with lyophilized coumarins. With the linear regression, deviation was 8.40% for the artificially depleted plasmas and 5.05% for coumarin-treated patients' lyophilized plasmas. The simpler regression method appears to be worthy of further study as the present report has demonstrated that if the calibrant plasmas are accurately certified with the thromboplastin International Reference Plasma (IRP) results approximate to the conventionally determined INR using the manual PT technique. Coagulometers require further assessment.     

农村地区高血压危险因素的病例对照研究

对四川省农村地区218例原发性高血压(其中包括109例临界高血压)进行配对(1:2)病例对照研究。资料分析采用了条件Logistic回归分析方法。研究结果提示心率、高血压家族史、环境噪声、体重指数(QI)等综合因素与临界高血压和确诊高血压均有显著的联系。心率、体重指数(QI)以及高血压家族史是原发性高血压较稳定的影响因素,心率可作为研究血压的必测指标。环境因素对原发性高血压的影响不可忽视。原发性高血压是遗传因素、环境因素等综合作用的结果。     

农村居民医疗服务潜在需求量及影响因素分析

目的 了解农村居民医疗服务的潜在需求及其影响因素。方法 采用分层多阶段整群抽样方法，对湖北省宜昌地区5县1839名农村居民进行问卷调查。结果 该地区治病未就诊率为13．21％，男女性未就诊率分别为12．01％，15．56％，采用Logistic回归分析方法，筛选出影响患病未就治的主要因素为性别、健康状况、对健康的重视程度、婚姻状况以及不同县等。结论 在农村要完善合作医疗保障制度，对医疗机构建设应以提高服务质量、降低成本、遏制费用增长为主要目的，并能提供更多的医疗服务，使患能及时利用医疗服务。     

血压家庭相似性研究

本文报道了北京市房山区１１４７人血压家庭相似性研究结果。亲子代回归法得出的血压遗传度估计值为０．４２（收缩压）和０．４８（舒张压），全同胞相关法得出的血压遗传度估计值为０．３７（收缩压）和０．５３（舒张压）。两种方法得出的遗传度估计值相差不大，这一结果提示血压的遗传符合加性多基因模型。本文报道的血压遗传度没有区分遗传效应和共同生活环境效应。此外，本文强调了将血压作为数量性状采用数量遗传学方法进行遗传度估计的合理性和有效性。     

一种新的正交参数选优法及其在非线性回归分析中的应用

非线性回归分析是工程中经常采用的一种用来估计数学模型参数的方法，该方法能否顺利运用与参数初始值的选择有极大关系。本研究提出一种新的正交参数选优法——阻尼正交表法，它不仅可以保证非线性回归分析算法的顺利收敛，而且能够显著提高后者的收敛速度，进而极大改善非线性回归分析算法的应用性能。本研究的数值试验及心肌造影超声心动图定量分析应用实例表明，作为对传统正交参数选优法的一种改进，阻尼正交表法在科学与工程计算或信号与信息处理领域有着很好的应用前景。     

Human parotid proline-rich proteins: correlation of genetic polymorphisms to dental caries

Parotid saliva contains a variety of proline-rich proteins. This study found that, among 306 children between the ages of 5 to 15 years, there is a significant increase in the decayed-missing-filled tooth surface (DMFS) score of the permanent teeth with age in children with the specific proline-rich protein phenotypes Pa and Pr. However, the increase in DMFS score of the permanent teeth of children was significantly greater in children with Pa+ and Pr22 than in those with the other phenotypes (Pa- or Pr11 and Pr12). The previously established close correlation between the Pa and Pr phenotypes and the genetic variants of salivary peroxidase (a powerful antibacterial system in the oral cavity) may provide an explanation for the relationship of certain proline-rich protein phenotypes to dental caries.     

有机氮源对红霉素发酵影响的具体分析

红色糖多孢菌的摇瓶培养基中使用不同有机氮源时红霉素的效价明显不同。通过对不同有机氮源所含营养成分的逐步回归分析,我们得到有机氮源中的苏氨酸为影响红霉素效价的主要因子。最后向对照培养基中添加苏氨酸,则使红霉素的效价比对照培养基提高了22.85%。     

药物的定量构效关系的方法学研究——改进的逐步回归算法

在定量的构效关系研究中,多重回归分析选人的参数,多是用穷举所有方程实现的。本文提出一种改进的逐步回归算法,计算实例表明,是个行之有效的方法。     

A model to predict long-term sustained response to interferon therapy in chronic hepatitis C

Interferon therapy is used widely for chronic hepatitis C but only a minority of treated patients achieve a long-lasting sustained response. We have developed, by logistic regression, a mathematical model to estimate the probability of sustained response in an individual patient with chronic hepatitis C when treated with interferon-α (IFN-α). The model, which includes age, sex, disease duration, pretreatment serum γ-glutamyl-transpeptidase, alanine aminotransferase and virus genotype, was developed from a database of 307 patients and validated in a new set of 200 patients. It performed well as goodness-of-fit ( P = 0.71 and P = 0.15 in the development and test sample, respectively) and discrimination (area under receiver operating curve = 0.79 in the development and 0.78 in the test sample, respectively). This model may provide decision support in the treatment of chronic hepatitis C with IFN-α.