99 research outputs found
Promotional Effect on Selective Catalytic Reduction of NO x
W and Ce are known to be a good promoters to improve selective catalytic reduction (SCR) activity for V2O5/TiO2 catalysts. This work aimed at finding the optimum ratio and loading of promoters (W and Ce) on V2O5/TiO2 catalyst in order to improve SCR reactivity in low temperature region and to minimize N2O formation in high temperature region. In addition, we changed the order of impregnation between W and Ce precursors on V2O5/TiO2 catalyst during the preparation and observed its effect on SCR activity and N2 selectivity. We utilized various analytical techniques, such as N2 adsorption-desorption, X-ray diffraction (XRD), and temperature-programmed reduction with hydrogen (H2 TPR) to investigate the physicochemical properties of catalysts. It was found that W- and Ce-overloaded V2O5/TiO2 catalyst such as W/Ce/V/TiO2 (15 : 15 : 1 wt%) showed the most remarkable DeNOx properties over the wide temperature region. Additionally, this catalyst significantly suppressed N2O formation during SCR reaction, especially in high temperature region (350–400°C). Based on the characterization results, it was found that such superior activity originated from the improved reducibility and morphology of W and Ce species on V2O5/TiO2 catalyst when they are incorporated together at high loading
Promotional Effect on Selective Catalytic Reduction of NO x with NH 3 over Overloaded W and Ce on V 2 O 5 /TiO 2 Catalysts
W and Ce are known to be a good promoters to improve selective catalytic reduction (SCR) activity for V 2 O 5 /TiO 2 catalysts. This work aimed at finding the optimum ratio and loading of promoters (W and Ce) on V 2 O 5 /TiO 2 catalyst in order to improve SCR reactivity in low temperature region and to minimize N 2 O formation in high temperature region. In addition, we changed the order of impregnation between W and Ce precursors on V 2 O 5 /TiO 2 catalyst during the preparation and observed its effect on SCR activity and N 2 selectivity. We utilized various analytical techniques, such as N 2 adsorption-desorption, X-ray diffraction (XRD), and temperature-programmed reduction with hydrogen (H 2 TPR) to investigate the physicochemical properties of catalysts. It was found that W-and Ce-overloaded V 2 O 5 /TiO 2 catalyst such as W/Ce/V/TiO 2 (15 : 15 : 1 wt%) showed the most remarkable DeNO x properties over the wide temperature region. Additionally, this catalyst significantly suppressed N 2 O formation during SCR reaction, especially in high temperature region (350-400 ∘ C). Based on the characterization results, it was found that such superior activity originated from the improved reducibility and morphology of W and Ce species on V 2 O 5 /TiO 2 catalyst when they are incorporated together at high loading
Copy Number Deletion Has Little Impact on Gene Expression Levels in Racehorses
Copy number variations (CNVs), important genetic factors for study of human diseases, may have as large of an effect on phenotype as do single nucleotide polymorphisms. Indeed, it is widely accepted that CNVs are associated with differential disease susceptibility. However, the relationships between CNVs and gene expression have not been characterized in the horse. In this study, we investigated the effects of copy number deletion in the blood and muscle transcriptomes of Thoroughbred racing horses. We identified a total of 1,246 CNVs of deletion polymorphisms using DNA re-sequencing data from 18 Thoroughbred racing horses. To discover the tendencies between CNV status and gene expression levels, we extracted CNVs of four Thoroughbred racing horses of which RNA sequencing was available. We found that 252 pairs of CNVs and genes were associated in the four horse samples. We did not observe a clear and consistent relationship between the deletion status of CNVs and gene expression levels before and after exercise in blood and muscle. However, we found some pairs of CNVs and associated genes that indicated relationships with gene expression levels: a positive relationship with genes responsible for membrane structure or cytoskeleton and a negative relationship with genes involved in disease. This study will lead to conceptual advances in understanding the relationship between CNVs and global gene expression in the horse
Genome-wide analysis of DNA methylation patterns in horse
Background: DNA methylation is an epigenetic regulatory mechanism that plays an essential role in mediating biological processes and determining phenotypic plasticity in organisms. Although the horse reference genome and whole transcriptome data are publically available the global DNA methylation data are yet to be known.
Results: We report the first genome-wide DNA methylation characteristics data from skeletal muscle, heart, lung, and cerebrum tissues of thoroughbred (TH) and Jeju (JH) horses, an indigenous Korea breed, respectively by methyl-DNA immunoprecipitation sequencing. The analysis of the DNA methylation patterns indicated that the average methylation density was the lowest in the promoter region, while the density in the coding DNA sequence region was the highest. Among repeat elements, a relatively high density of methylation was observed in long interspersed nuclear elements compared to short interspersed nuclear elements or long terminal repeat elements. We also successfully identified differential methylated regions through a comparative analysis of corresponding tissues from TH and JH, indicating that the gene body regions showed a high methylation density.
Conclusions: We provide report the first DNA methylation landscape and differentially methylated genomic regions (DMRs) of thoroughbred and Jeju horses, providing comprehensive DMRs maps of the DNA methylome. These data are invaluable resource to better understanding of epigenetics in the horse providing information for the further biological function analyses.open1
Whole transcriptome analyses of six thoroughbred horses before and after exercise using RNA-Seq
Background: Thoroughbred horses are the most expensive domestic animals, and their running ability and knowledge about their muscle-related diseases are important in animal genetics. While the horse reference genome is available, there has been no large-scale functional annotation of the genome using expressed genes derived from transcriptomes.
Results: We present a large-scale analysis of whole transcriptome data. We sequenced the whole mRNA from the blood and muscle tissues of six thoroughbred horses before and after exercise. By comparing current genome annotations, we identified 32,361 unigene clusters spanning 51.83 Mb that contained 11,933 (36.87%) annotated genes. More than 60% (20,428) of the unigene clusters did not match any current equine gene model. We also identified 189,973 single nucleotide variations (SNVs) from the sequences aligned against the horse reference genome. Most SNVs (171,558 SNVs; 90.31%) were novel when compared with over 1.1 million equine SNPs from two SNP databases. Using differential expression analysis, we further identified a number of exercise-regulated genes: 62 up-regulated and 80 down-regulated genes in the blood, and 878 up-regulated and 285 down-regulated genes in the muscle. Six of 28 previously-known exercise-related genes were over-expressed in the muscle after exercise. Among the differentially expressed genes, there were 91 transcription factor-encoding genes, which included 56 functionally unknown transcription factor candidates that are probably associated with an early regulatory exercise mechanism. In addition, we found interesting RNA expression patterns where different alternative splicing forms of the same gene showed reversed expressions before and after exercising.
Conclusion: The first sequencing-based horse transcriptome data, extensive analyses results, deferentially expressed genes before and after exercise, and candidate genes that are related to the exercise are provided in this study.close151
Clinical Characteristics of a Nationwide Hospital-based Registry of Mild-to-Moderate Alzheimer's Disease Patients in Korea: A CREDOS (Clinical Research Center for Dementia of South Korea) Study
With rapid population aging, the socioeconomic burden caused by dementia care is snowballing. Although a few community-based studies of Alzheimer's disease (AD) have been performed in Korea, there has never been a nationwide hospital-based study thereof. We aimed to identify the demographics and clinical characteristics of mild-to-moderate AD patients from the Clinical Research Center for Dementia of Korea (CREDOS) registry. A total of 1,786 patients were consecutively included from September 2005 to June 2010. Each patient underwent comprehensive neurological examination, interview for caregivers, laboratory investigations, neuropsychological tests, and brain MRI. The mean age was 74.0 yr and the female percentage 67.0%. The mean period of education was 7.1 yr and the frequency of early-onset AD (< 65 yr old) was 18.8%. Among the vascular risk factors, hypertension (48.9%) and diabetes mellitus (22.3%) were the most frequent. The mean score of the Korean version of Mini-Mental State Examination (K-MMSE) was 19.2 and the mean sum of box scores of Clinical Dementia Rating (CDR-SB) 5.1. Based on the well-structured, nationwide, and hospital-based registry, this study provides the unique clinical characteristics of AD and emphasizes the importance of vascular factors in AD in Korea
Standardization of the methods and reference materials used to assess virus content in varicella vaccines
BACKGROUND: In Korea, every vaccine lot is tested by the National Center for Lot Release (NCLR) in accordance with the national lot release procedures to ensure the safety and efficacy of vaccines. These quality tests examine the virus content in varicella vaccines via plaque assays (either the agar overlay method [AOM] or plaque staining method [PSM]), according to the procedures suggested by the Korean Reference Material for the Varicella Vaccine (KRMVV) or the manufacturer’s standard in-house protocol. AIM: To standardize the virus content tests, viral titers in the KRMVV were measured using the PSM at four participating laboratories in a collaborative study. With the aim of developing a standardized method using the KRMVV as a positive control, we compared the ability of the two test methods, AOM and PSM, to accurately and reproducibly determine the virus content of two commercial varicella vaccines. RESULTS: The results showed that the standardized method (PSM) was more suitable for quality control analysis of the varicella vaccine. CONCLUSION: Use of a standardized method (PSM) according to the Korean reference material will improve the reliability and objectivity of lot release testing
Genome-Wide Analysis of DNA Methylation before- and after Exercise in the Thoroughbred Horse with MeDIP-Seq
Athletic performance is an important criteria used for the selection of superior horses. However, little is known about exercise-related epigenetic processes in the horse. DNA methylation is a key mechanism for regulating gene expression in response to environmental changes. We carried out comparative genomic analysis of genome-wide DNA methylation profiles in the blood samples of two different thoroughbred horses before and after exercise by methylated-DNA immunoprecipitation sequencing (MeDIP-Seq). Differentially methylated regions (DMRs) in the pre- and post-exercise blood samples of superior and inferior horses were identified. Exercise altered the methylation patterns. After 30 min of exercise, 596 genes were hypomethylated and 715 genes were hypermethylated in the superior horse, whereas in the inferior horse, 868 genes were hypomethylated and 794 genes were hypermethylated. These genes were analyzed based on gene ontology (GO) annotations and the exercise-related pathway patterns in the two horses were compared. After exercise, gene regions related to cell division and adhesion were hypermethylated in the superior horse, whereas regions related to cell signaling and transport were hypermethylated in the inferior horse. Analysis of the distribution of methylated CpG islands confirmed the hypomethylation in the gene-body methylation regions after exercise. The methylation patterns of transposable elements also changed after exercise. Long interspersed nuclear elements (LINEs) showed abundance of DMRs. Collectively, our results serve as a basis to study exercise-based reprogramming of epigenetic traitsclose
- …