RC_Link: Genetic linkage analysis using Bayesian networks

Genetic linkage analysis is a statistical method for mapping genes onto chromosomes, and is useful for detecting and predicting diseases. One of its current limitations is the computational complexity of the problems of interest. This research presents methods for mapping genetic linkage problems as Bayesian networks and then addresses novel techniques for making the problems more tractable. The result is a new tool for solving these problems called RC_Link, which in many cases is orders of magnitude faster than existing tools.     

Genome-wide linkage analysis for ocular and nasal anthropometric traits in a Mongolian population

Anthropometric traits for eyes and nose are complex quantitative traits influenced by genetic and environmental factors. To date, there have been few reports on the contribution of genetic influence to these traits in Asian populations. The aim of this study was to determine the genetic effect and quantitative trait locus (QTL) of seven traits eyes- and nose-related anthropometric measurements in an isolated Mongolian population. Frontal and lateral photographs were obtained from 1,014 individuals (434 males and 580 females) of Mongolian origin. A total of 349 short tandem repeat markers on 22 autosomes were genotyped for each individual. Heritability estimates of the seven ocular and nasal traits, adjusted for significant covariates, ranged from 0.48 to 0.90, providing evidence for a genetic influence. Variance-component linkage analyses revealed 10 suggestive linkage signals on 5q34 (LOD=3.2), 18q12.2 (LOD=2.7), 5q15 (LOD=2.0), 9q34.2 (LOD=1.9), 5q34 (LOD=1.9), 17q22 (LOD=1.9), 13q33.3 (LOD=2.7), 1q36.22 (LOD=1.9), 4q32.1 (LOD=2.1) and 15q22.31 (LOD=2.9). Our study provides the first evidence that genetics influences nasal and ocular traits in a Mongolian population. Additional collaborative efforts will further extend our understanding of the link between genetic factors and human anthropometric traits.     

Gene mapping study for constitutive skin color in an isolated Mongolian population

To elucidate the genes responsible for constitutive human skin color, we measured the extent of skin pigmentation in the buttock, representative of lifelong non-sun-exposed skin, and conducted a gene mapping study on skin color in an isolated Mongolian population composed of 344 individuals from 59 families who lived in Dashbalbar, Mongolia. The heritability of constitutive skin color was 0.82, indicating significant genetic association on this trait. Through the linkage analysis using 1,039 short tandem repeat (STR) microsatellite markers, we identified a novel genomic region regulating constitutive skin color on 11q24.2 with an logarithm of odds (LOD) score of 3.39. In addition, we also found other candidate regions on 17q23.2, 6q25.1, and 13q33.2 (LOD ≥ 2). Family-based association tests on these regions with suggestive linkage peaks revealed ten and two significant single nucleotide polymorphisms (SNPs) on the linkage regions of chromosome 11 and 17, respectively. We were able to discover four possible candidate genes that would be implicated to regulate human skin color: ETS1, UBASH3B, ASAM, and CLTC.     

基于ATmegal6和μC／OSⅡ低成本的三轴联动平台的设计

提出了一种低成本的运动控制平台设计方案。将μC／OSⅡ嵌入式实时操作系统移植到平台采用的单片机中，并采用步进电机细分技术实现了三轴平台的联动。实验测定了三轴联动平台对命令的延迟响应时间，结果表明本方案可以应用于低成本的自动化设备中。     

Relaxing the Assumptions of the Multilevel Single Linkage Algorithm

In this paper we relax the assumptions of a well known algorithm for continuous global optimization, Multilevel Single Linkage (MLSL). It is shown that the good theoretical properties of MLSL are shared by a slightly different algorithm, Non-monotonic MLSL (NM MLSL), but under weaker assumptions. The main difference with MLSL is the fact that in NM MLSL some non-monotonic sequences of sampled points are also considered in order to decide whether to start or not a local search, while MLSL only considers monotonic decreasing sequences. The modification is inspired by non-monotonic methods for local searches. This revised version was published online in July 2006 with corrections to the Cover Date.     

Solid‐State Interconversions: Unique 100 % Reversible Transformations between the Ground and Metastable States in Single‐Crystals of a Series of Nickel(II) Nitro Complexes

The solid‐state, low‐temperature linkage isomerism in a series of five square planar group 10 phosphino nitro complexes have been investigated by a combination of photocrystallographic experiments, Raman spectroscopy and computer modelling. The factors influencing the reversible solid‐state interconversion between the nitro and nitrito structural isomers have also been investigated, providing insight into the dynamics of this process. The cis‐[Ni(dcpe)(NO₂)₂] ( 1 ) and cis‐[Ni(dppe)(NO₂)₂] ( 2 ) complexes show reversible 100 % interconversion between the η¹‐NO₂ nitro isomer and the η¹‐ONO nitrito form when single‐crystals are irradiated with 400 nm light at 100 K. Variable temperature photocrystallographic studies for these complexes established that the metastable nitrito isomer reverted to the ground‐state nitro isomer at temperatures above 180 K. By comparison, the related trans complex [Ni(PCy₃)₂(NO₂)₂] ( 3 ) showed 82 % conversion under the same experimental conditions at 100 K. The level of conversion to the metastable nitrito isomers is further reduced when the nickel centre is replaced by palladium or platinum. Prolonged irradiation of the trans‐[Pd(PCy₃)₂(NO₂)₂] ( 4 ) and trans‐[Pt(PCy₃)₂(NO₂)₂] ( 5 ) with 400 nm light gives reversible conversions of 44 and 27 %, respectively, consistent with the slower kinetics associated with the heavier members of group 10. The mechanism of the interconversion has been investigated by theoretical calculations based on the model complex [Ni(dmpe)Cl(NO₂)].     

Steady‐State and Pseudo‐Steady‐State Photocrystallographic Studies on Linkage Isomers of [Ni(Et4dien)(η2‐O,ON)(η1‐NO2)]: Identification of a New Linkage Isomer

At temperatures below 150 K, the photoactivated metastable endo‐nitrito linkage isomer [Ni(Et₄dien)(η²‐O,ON)(η¹‐ONO)] (Et₄dien=N,N,N′,N′‐tetraethyldiethylenetriamine) can be generated with 100 % conversion from the ground state nitro‐(η¹‐NO₂) isomer on irradiation with 500 nm light, in the single crystal by steady‐state photocrystallographic techniques. Kinetic studies show the system is no longer metastable above 150 K, decaying back to the ground state nitro‐(η¹‐NO₂) arrangement over several hours at 150 K. Variable‐temperature kinetic measurements in the range of 150–160 K show that the rate of endo‐nitrito decay is highly dependent on temperature, and an activation energy of E_act=+48.6(4) kJ mol^?1 is calculated for the decay process. Pseudo‐steady‐state experiments, where the crystal is continually pumped by the light source for the duration of the X‐ray experiment, show the production of a previously unobserved, exo‐nitrito‐(η¹‐ONO) linkage isomer only at temperatures close to the metastable limit (ca. 140–190 K). This exo isomer is considered to be a transient excited‐state species, as it is only observed in data collected by pseudo‐steady‐state methods.     

Influence of chemical structure on the optical properties of new side-chain polymers containing cholesterol

Poly[1-(cholesteryloxyhexyloxy)ethylene] (PHET) and poly[1-(cholesteryloxycarbonyl-hexyloxy)ethylene] (PHES) were prepared by reacting poly(vinyl alcohol) with cholesteryloxyhexyloxy bromides (CHB) or cholesteryloxycarbonylhexyloxy bromides (CEHB), and their thermal and optical properties were investigated. PHET and PHES exhibited monotropic cholesteric phases; however, their thermal behaviours depended on the cholesteryl groups and alkylene spacers with different chemical structures. PHET did not display reflection colours over its entire cholesteric range, whereas PHES did display reflection colours. These results suggested that the thermal stability and helical twisting power (HTP) of these polymers strongly depend on the difference in the chemical structures of the flexible spacer via cholesterol. The mesophase properties of PHET and PHES differed substantially from those of poly(cholesteryl-ω-acryloyloxyalkanoates). The results indicate that the mode of chemical linkage between the side-chain group and the main chain as well as that between the alkylene spacer and side chain play important roles in determining the thermal stability, mesophorphic structure and HTP of the cholesteric mesophases.