重油和沥青中饱和碳的定量估计

建立了较完整的估计重油和沥青中饱和碳浓度数方法，其中包括环烷桥头碳、环烷甲基取代碳、环烷烷基（≥Ｃ２）取代碳等。基于理论分析，建立了估计环间的桥链和各种平均结构参数的方法，包括平均芳环环核数和环烷环环核数、芳环和环烷环烷工取代度、单元片上芳环和环烷环数。从实验数据出发，提出了烷基链长分布的公式。     

Ontogenetic Development of 5-HT1D Receptors in Human Brain: An Autoradiographic Study

The pattern of pre- and postnatal appearance of 5-HT_1D receptors throughout the different areas of the human brain was studied by quantitative in vitro autoradiography, using [¹²⁵I]GTI (serotonin O -carboxymethyl-glycyl-[¹²⁵I]tyrosinamide) as a ligand. The anatomical distribution of 5-HT_1D receptors in neonatal, infant and children's brain was in good agreement with that observed in the adult, the basal ganglia and substantia nigra being the most intensely labelled areas. The development of these receptors throughout the human brain was mainly postnatal: low densities of [¹²⁵I]GTI binding sites were observed at the fetal/neonatal stage in most regions analyzed, in contrast with the high levels of labelling found in infant and children's brains. Indeed, in a number of regions, including the globus pallidus, substantia nigra and visual cortex, a peak of overexpression of 5-HT_1D receptors was observed in the first decade of life. Such overexpression could support a regulatory role for 5-HT_1D receptors in advanced periods of the CNS developmental process. Our results also indicate that the administration of drugs acting on 5-HT_1D receptors during the early postnatal period of life could result in modifications of their properties, as these receptors are already functional in this period.     

Interaction of glucagon with artificial lipid bilayer membranes

The enhancement of fluorescence emission from the tryptophan residue of glucagon, the quenching of that emission with acrylamide and with 5-doxyl and 16-doxyl stearic acid, circular dichroism spectra, the release of 6-carboxytluorescein, and polarized infrared attenuated total reflection (IR-ATR) spectra were used to study the interaction of glucagon with intact lipid vesicles and flat bilayers. Dimyristoylphosphatidylcholine bound the peptide only below the main transition temperature, thus confirming earlier results of Epand et al. (1977). However, the peptide is also bound by vesicles of unsaturated lipids above their transition temperature, suggesting an influence of lipid area on the binding process. Circular dichroism showed that binding to such vesicles also increases the helix content of glucagon. The IR-ATR study and a comparison with dynorphin-A-(I-13)-tridecapeptide revealed profound differences in orientation of the two peptides. The dichroic ratios and the derived order parameters indicated an isotropic orientation of the helical segments of glucagon, but did not exclude a principal orientation of the molecules lying flat on the nienibrane surface. In contrast, the axis of the dynorphin helix is clearly oriented normal to the interface. The two peptides also differ in their rates of 6-carboxyfluorescein release, suggesting a deeper penetration of the primary amphiphilic helix of dynorphin A-(I-13) than of the secondary amphiphilic helix of glucagon.     

Association and linkage with quantitative traits

This paper examines two approaches for the analysis of quantitative traits: (1) association studies and (2) linkage studies. The trait studied was Q1 from simulated Problem 2 data set in Genetic Analysis Workshop 9. Our purpose was to evaluate associations present in the data, to identify nongenetic and genetic predictors of the trait, and to explore the simulated genome for linkage. Through the association study, we found evidence for the primary major gene associated with this trait. The linkage study found evidence of residual genetic effect acting through other traits. Adjustments of Q1 for Q2 and Q3 led to a failure to find significant effects of MG2 and MG3. This supports the suggestion that adjustment for genetically influenced traits for effects of other genetic traits can reduce the power to detect major gene effects. In summary, we detected the major gene directly associated with the trait of interest through association studies. Linkage analysis detected evidence for two other genes associated to a lesser degree with the trait. © 1995 Wiley-Liss, Inc.     

Quantifying arbitrary magnetic susceptibility distributions with MR.

Magnetic susceptibility, as a physical property of materials, plays important roles in many physical, chemical, engineering, and medical applications. Its quantification becomes of significant interest when MRI becomes a commonly used technique in biomedical applications. A general method is presented here for quantifying arbitrary magnetic susceptibility distributions in a localized region on the basis of first principles of magnetic induction field distributions in space. A proof of the concept was demonstrated by computer simulations. The study establishes the methodological basis for quantitative magnetic susceptibility imaging with MR.     

The ordered transmission disequilibrium test: detection of modifier genes

We consider the problem of detection of modifier genes that lead to variations in a disease‐related continuous variable (DRCV), such as the age of onset or a measure of disease severity, in a strategy of candidate genes. We propose a novel method, the ordered transmission disequilibrium test (OTDT), to test for a relation between the clinical heterogeneity expressed by a DRCV and marker genotypes of a candidate gene. The OTDT applies to trio families with one patients and his parents, all three genotyped at a bi‐allelic marker M. The OTDT aims to find a critical value of the DRCV which separates the sample of families in two subsamples in which the transmission rates are significantly different. We investigate the power of the method by simulations under various genetic models and covariate distributions and compare it with a linear regression analysis. Genet. Epidemiol. 2008. ©2008 Wiley‐Liss, Inc.     

MR流量测定的实验研究

目的探讨MR流量测量与不同感兴趣区(ROI)直径的关系。方法使用Philips 1.5T双梯磁共振机流量测定程序,测量2mm内径塑胶管中不同流量的水(0.5、1.0、1.5、2.0、2.5ml/s),不同流向(流入及流出方向)、不同ROI位置(测量图中心区和偏中心区)与不同的ROI直径(直径0.5、1.0、1.5、2.0mm)流量变化关系,统计计算标准的ROI直径。结果在不同流量、流向和测量位置中,流量与ROI直径大小存在明显的直线相关(r>0.95,P<0.05),ROI直径大小显著地影响测量结果,当ROI直径取值等于测量图直径的0.6040±0.0480时,所测结果与实际流量一致。在不同流量下的不同流向及ROI位置对流量测定无影响(P>0.05)。结论对直径2mm流量测定,应选取测量图上直径的0.6040±0.0480 ROI进行。     

Synaptosomal Na, K-ATPase during forebrain ischemia in Mongolian gerbils

We studied the activity and kinetic parameters of synaptosomal Na, K-ATPase during 15 min of forebrain ischemia and following 60 min of reperfusion produced by reversible common carotid occlusion in Mongolian gerbils. A synaptosomal fraction was obtained by both differential centrifugation of brain tissue homogenate and centrifugation of crude mitochondrial fraction at a discontinual sucrose density gradient. We found two components of ATP concentration dependence of ATP hydrolysis that represent two types of ATP-binding sites: high affinity and low affinity. Neither ischemia nor reperfusion affected kinetic parameters of a high-affinity site. However, lowaffinity site parameters were affected by both ischemia and ischemia followed by reperfusion. Maximal velocity (V _max) decreased by 43 and 42% after ischemia and after ischemia/reperfusion, respectively. The apparentK _m for ATP decreased by 52% after ischemia and by 47% after ischemia/reperfusion. The apparent affinities for K⁺ and Na⁺ were determined from the ATP hydrolysis rate as a function of Na⁺ and K⁺ concentrations. We found the half-maximal activation constant for K⁺ (K _a K⁺) increased by 60% after ischemia and by 146% after ischemia/reperfusion. On the other hand, we found thatK _aNa⁺ decreased significantly after ischemia/reperfusion (16%). We concluded that it is the dephosphorylation step of the ATPase reation cycle that is primarily affected by both ischemia and ischemia/reperfusion. This might be caused by alteration of the protein molecule and/or its surroundings subsequent to ischemia.     

Quantitative Analysis of the Tomographic Technetium－99m MIBI （~（99m）Tc－MIBI） Myocardial Bullseye Display： Application to Diag

ＱｕａｎｔｉｔａｔｉｖｅＡｎａｌｙｓｉｓｏｆｔｈｅＴｏｍｏｇｒａｐｈｉｃＴｅｃｈｎｅｔｉｕｍ－９９ｍＭＩＢＩ（~（９９ｍ）Ｔｃ－ＭＩＢＩ）ＭｙｏｃａｒｄｉａｌＢｕｌｌｓｅｙｅＤｉｓｐｌａｙ：ＡｐｐｌｉｃａｔｉｏｎｔｏＤｉａｇｎｏｓｉｓｏｆＣｏｒｏｎａ?..