2,573 research outputs found

    Comparative genome analysis in the pig as a model for understanding human obesity

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    This dissertation reports on studies of the pig genome as a model to identify obesity-related genes. Pig geneticists have sought to reduce fat in their pigs through selective breeding, and these efforts ultimately improved the genetic potential in the pig for higher growth, increased efficiency of conversion of food into body weight and lower fat percentage in the body. Therefore, the genetic information obtained from lean growth in the pig can be applicable to studying the genetic basis of human obesity and other related health problems. A three-generation pig family and several commercial lines of pigs were used to study porcine obesity quantitative trait loci (QTL), and genes for the relevant phenotypes to human growth and obesity. Several candidate genes were successfully localized within the porcine obesity QTL and the comparative locations of these QTL and candidate genes were discussed in the present study. Furthermore, the relationships between DNA polymorphisms of the candidate genes and a variety of phenotypic measurements were studied. These results provide important insights into the role of biological candidate genes in obesity and other related metabolic disorders. The functional properties of a naturally occurring variant of porcine melanocortin-4 receptor ( MC4R) gene were comparatively characterized to determine functionally important structural amino acid residues in the MC4R sequences. This research also discovered a unique imprinting phenotype in the porcine delta-like 1 (DLK1) locus. The imprinting phenotype was first found in the callipyge locus in sheep and called \u27polar overdominance\u27. However, further identification has been elusive in other mammals. The results of the porcine DLK1 locus indicate that the inheritance mechanism of polar overdominance for callipyge sheep might have a conserved role for growth and fat deposition phenotypes in pigs and the DLK1 gene might be an important player for the imprinting phenotypes. This dissertation demonstrates the useful value of comparative genomic study of pigs as a model organism to investigate genes of interest for human health, especially obesity, and the results also have implications for the development of improved genetic selection programs for the targeted traits of interest in pig production systems

    On Blocking Collisions between People, Objects and other Robots

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    Intentional or unintentional contacts are bound to occur increasingly more often due to the deployment of autonomous systems in human environments. In this paper, we devise methods to computationally predict imminent collisions between objects, robots and people, and use an upper-body humanoid robot to block them if they are likely to happen. We employ statistical methods for effective collision prediction followed by sensor-based trajectory generation and real-time control to attempt to stop the likely collisions using the most favorable part of the blocking robot. We thoroughly investigate collisions in various types of experimental setups involving objects, robots, and people. Overall, the main contribution of this paper is to devise sensor-based prediction, trajectory generation and control processes for highly articulated robots to prevent collisions against people, and conduct numerous experiments to validate this approach

    A Study on the Factors That Influence the Acoustic Performance of a Steel Stud Wall Assembly

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    With the recent introduction of light gauge steel framing systems in the concrete-dominated Korean construction industry, more buildings are built with drywall that is mainly composed of steel studs and gypsum boards. While load-bearing steel studs are extensively applied in residential construction, nonload-bearing steel studs are applied in various building fields such as commercial, educational, as well as residential. As building projects involving steel stud walls are becoming to increase, higher demands in performance are requested from architects and builders, especially in the field of sound performance. A series of acoustic test were performed in the nationally certified sound-testing laboratory at Korean Institute of Construction Technology (KICT) in order to evaluate and analyze factors that influence acoustic performance of steel stud wall assemblies. Factors affecting the acoustic performance of steel stud walls that are analyzed in this paper include among others, the composition and structure of steel studs, stud spacing, stud thickness, stud size, use of resilient channel, screw spacing, etc. Factors relating to gypsum boards that were tested as part of the evaluation of acoustic performance are not included in this paper. Results of this study, which is co-funded by 3 major gypsum board companies in Korea, are being used to develop stud wall assemblies that meet the required acoustic performance for unit-to-unit separating walls, as well as present architects and builders with a better understanding on the sound behavior of steel stud drywall

    Palladium Catalysts for Dehydrogenation of Ammonia Borane with Preferential B−H Activation

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    Cationic Pd(II) complexes catalyzed the dehydrogenation of ammonia borane in the most efficient manner with the release of 2.0 equiv of H_2 in less than 60 s at 25 °C. Most of the hydrogen atoms were obtained from the boron atom of the ammonia borane. The first step of the dehydrogenation reaction was elaborated using density functional theory calculations

    Sleeve Lobectomy as an Alternative Procedure to Pneumonectomy for Non-small Cell Lung Cancer

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    IntroductionThe aim of this study is to compare the outcomes of sleeve lobectomy (SL) and pneumonectomy (PN) and to determine which one is more acceptable standard procedure for patients with non-small cell lung cancer.MethodsFrom 1996 to 2005, 424 patients underwent SL (n = 157) and PN (n = 267) in our institution. Propensity score matching analysis was performed to compare these two groups for mortality, morbidity, survival, recurrence, and postoperative pulmonary function.ResultsIn each group, 105 patients were eligible for analysis. The operative mortality was lower in the SL group (1.0%) than the PN group (8.6%), (p < 0.0001). The morbidity was similar (33.4% versus 29.5%, p = 0.376). The 5-year survival was lower in the PN group (PN, 32.14% versus SL, 58.43%, p = 0.0002). The recurrence pattern (locoregional versus distant) did not differ between two groups (p = 0.180). The mean actual postoperative first second forced expiratory volume in the patients underwent SL was 2.05 ± 0.55 liter, which increased by 7.9% compared with the predicted-postoperative first second forced expiratory volume.ConclusionsOur results showed that the SL can be performed with low operative risk and may offer superior survival and better postoperative pulmonary function compared with the PN in selected patients. If anatomically feasible, a SL must be considered as a favorable alternative to PN in patients with non-small cell lung cancer

    Genome-Wide Association Analyses of Biological Responses to Heat Stress in Pigs

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    With genetic selection for rapid, lean tissue accretion, pigs are becoming increasingly sensitive to heat stress (HS) due to their physiological limitations such as the lack of functional sweat glands to effectively dissipate heat. Increased respiration rate and reduced feed intake are immediate and conserved biological responses to HS in pigs and other livestock species. Genetic differences in how animals respond to high ambient temperatures have been previously reported, but genetic factors contributing to the response variability remain ill-defined. In this study, porcine high density single nucleotide polymorphism (SNP) beadchips were used to genotype 236 female pigs who had been exposed to HS conditions, and analyzed to detect chromosomal regions associated with biological responses measured before and after HS, including rectal temperature, respiration rate, feed intake, and body weight loss. We identified significant gene region associations for rectal temperature on SSC12, respiration rate on SSC14 and SSC16, as well as feed efficiency and weight loss on SSC13. Further analyses of these detected regions will likely reveal potential candidate genes and suggest molecular mechanisms contributing to the variability in the biological response of pigs to environmentally-induced hyperthermia

    Genetic Structure of and Evidence for Admixture between Western and Korean Native Pig Breeds Revealed by Single Nucleotide Polymorphisms

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    Comprehensive information on genetic diversity and introgression is desirable for the design of rational breed improvement and conservation programs. Despite the concerns regarding the genetic introgression of Western pig breeds into the gene pool of the Korean native pig (KNP), the level of this admixture has not yet been quantified. In the present study, we genotyped 93 animals, representing four Western pig breeds and KNP, using the porcine SNP 60K BeadChip to assess their genetic diversity and to estimate the level of admixture among the breeds. Expected heterozygosity was the lowest in Berkshire (0.31) and highest in Landrace (0.42). Population differentiation (FST) estimates were significantly different (p<0.000), accounting for 27% of the variability among the breeds. The evidence of inbreeding observed in KNP (0.029) and Yorkshire (0.031) may result in deficient heterozygosity. Principal components one (PC1) and two (PC2) explained approximately 35.06% and 25.20% of the variation, respectively, and placed KNP somewhat proximal to the Western pig breeds (Berkshire and Landrace). When K = 2, KNP shared a substantial proportion of ancestry with Western breeds. Similarly, when K = 3, over 86% of the KNP individuals were in the same cluster with Berkshire and Landrace. The linkage disquilbrium (LD) values at r2 0.3, the physical distance at which LD decays below a threshold of 0.3, ranged from 72.40 kb in Landrace to 85.86 kb in Yorkshire. Based on our structure analysis, a substantial level of admixture between Western and Korean native pig breeds was observed
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