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Search Results: 1 - 10 of 305289 matches for " Y.-D. Ida Chen "
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Insulin Resistance in Pregnancy Is Correlated with Decreased Insulin Receptor Gene Expression in Omental Adipose: Insulin Sensitivity and Adipose Tissue Gene Expression in Normal Pregnancy  [PDF]
Arnold M. Mahesan, Dotun Ogunyemi, Eric Kim, Anthea B. M. Paul, Y.-D. Ida Chen
Journal of Diabetes Mellitus (JDM) , 2016, DOI: 10.4236/jdm.2016.61011
Abstract: Aims: To determine correlations of insulin sensitivity to gene expression in omental and subcutaneous adipose tissue of non-obese, non-diabetic pregnant women. Methods: Microarray gene profiling was performed on subcutaneous and omental adipose tissue from 14 patients and obtained while fasting during non-laboring Cesarean section, using Illumina HumanHT-12 V4 Expression BeadChips. Findings were validated by real-time PCR. Matusda-Insulin sensitivity index (IS) and homeostasis model assessment of insulin resistance (HOMA-IR) were calculated from glucose and insulin levels obtained from a frequently sampled oral glucose tolerance test, and correlated with gene expression. Results: Of genes differentially expressed in omental vs. subcutaneous adipose, in omentum 12 genes were expressed toward insulin resistance, whereas only 5 genes were expressed toward insulin sensitivity. In particular, expression of the insulin receptor gene (INSR), which initiates the insulin signaling cascade, is strongly positively correlated with IS and negatively with HOMA-IR in omental tissue (r = 0.84). Conclusion: Differential gene expression in omentum relative to subcutaneous adipose showed a pro-insulin resistance profile in omentum. A clinical importance of omental adipose is observed here, as downregulation of insulin receptor in omentum is correlated with increased systemic insulin resistance.
Differentially expressed genes in adipocytokine signaling pathway of adipose tissue in pregnancy  [PDF]
Dotun Ogunyemi, Jun Xu, Arnold M. Mahesan, Steve Rad, Eric Kim, Jacqueline Yano, Carolyn Alexander, Jerome I. Rotter, Y.-D. Ida Chen
Journal of Diabetes Mellitus (JDM) , 2013, DOI: 10.4236/jdm.2013.32013
Abstract:

Objective: To profile the differential gene expression of the KEGG Adipocytokine Signaling pathway in omental compared to subcutaneous tissue in normal pregnancy. Study Design: Subjects included 14 nonobese, normal glucose tolerant, healthy pregnant women. Matched omental and subcutaneous tissue were obtained at elective cesarean delivery. Gene expression was evaluated using microarray and validated by RT-PCR. Differential gene expression was defined as ≥1.5 fold increase at p < 0.05. Results: Six genes were significantly downregulated with two upregulated genes in omental tissue. Downregulation of Adiponectin and Insulin Receptor substrate, key genes mediating insulin sensitivity, were observed with borderline upregulation of GLUT-1. There were downregulations of CD36 and acyl-CoA Synthetase Long-chain Family Member 1which are genes involved in fatty acid uptake and activation. There was a novel expression of Carnitine palmitoyltransferase 1C. Conclusion: Differential gene expression of Adipocytokine Signaling Pathway in omental relative to subcutaneous adipose tissue in normal pregnancy suggests a pattern of insulin resistance, hyperlipidemia, and inflammation.

A Multinomial Ordinal Probit Model with Singular Value Decomposition Method for a Multinomial Trait
Soonil Kwon,Mark O. Goodarzi,Kent D. Taylor,Jinrui Cui,Y.-D. Ida Chen,Jerome I. Rotter,Willa Hsueh,Xiuqing Guo
Journal of Probability and Statistics , 2012, DOI: 10.1155/2012/419832
Abstract: We developed a multinomial ordinal probit model with singular value decomposition for testing a large number of single nucleotide polymorphisms (SNPs) simultaneously for association with multidisease status when sample size is much smaller than the number of SNPs. The validity and performance of the method was evaluated via simulation. We applied the method to our real study sample recruited through the Mexican-American Coronary Artery Disease study. We found 3 genes (SORCS1, AMPD1, and PPARα) to be associated with the development of both IGT and IFG, while 5 genes (AMPD2, PRKAA2, C5, TCF7L2, and ITR) with the IGT mechanism only and 6 genes (CAPN10, IL4, NOS3, CD14, GCG, and SORT1) with the IFG mechanism only. These data suggest that IGT and IFG may indicate different physiological mechanism to prediabetes, via different genetic determinants.
Genome-Wide Association of Pericardial Fat Identifies a Unique Locus for Ectopic Fat
Caroline S. Fox ,Charles C. White,Kurt Lohman,Nancy Heard-Costa,Paul Cohen,Yingying Zhang,Andrew D. Johnson,Valur Emilsson,Ching-Ti Liu,Y.-D. Ida Chen,Kent D. Taylor,Matthew Allison,Matthew Budoff,The CARDIoGRAM Consortium,Jerome I. Rotter,J. Jeffrey Carr,Udo Hoffmann,Jingzhong Ding,L. Adrienne Cupples,Yongmei Liu
PLOS Genetics , 2012, DOI: 10.1371/journal.pgen.1002705
Abstract: Pericardial fat is a localized fat depot associated with coronary artery calcium and myocardial infarction. We hypothesized that genetic loci would be associated with pericardial fat independent of other body fat depots. Pericardial fat was quantified in 5,487 individuals of European ancestry from the Framingham Heart Study (FHS) and the Multi-Ethnic Study of Atherosclerosis (MESA). Genotyping was performed using standard arrays and imputed to ~2.5 million Hapmap SNPs. Each study performed a genome-wide association analysis of pericardial fat adjusted for age, sex, weight, and height. A weighted z-score meta-analysis was conducted, and validation was obtained in an additional 3,602 multi-ethnic individuals from the MESA study. We identified a genome-wide significant signal in our primary meta-analysis at rs10198628 near TRIB2 (MAF 0.49, p = 2.7×10-08). This SNP was not associated with visceral fat (p = 0.17) or body mass index (p = 0.38), although we observed direction-consistent, nominal significance with visceral fat adjusted for BMI (p = 0.01) in the Framingham Heart Study. Our findings were robust among African ancestry (n = 1,442, p = 0.001), Hispanic (n = 1,399, p = 0.004), and Chinese (n = 761, p = 0.007) participants from the MESA study, with a combined p-value of 5.4E-14. We observed TRIB2 gene expression in the pericardial fat of mice. rs10198628 near TRIB2 is associated with pericardial fat but not measures of generalized or visceral adiposity, reinforcing the concept that there are unique genetic underpinnings to ectopic fat distribution.
Improved Channel Estimation and MAI-Robust Schemes for Wireless Ofdma System
Y.-D. Lee;D.-H. Park;Hyoung-Kyu Song
PIER , 2008, DOI: 10.2528/PIER08010403
Abstract: This paper presents an investigation into improving the channel estimation scheme and reducing the effects of symbol timing misalignment when OFDMA is used as an access scheme. Under OFDMA uplink channel environments, appropriate symbol length of CAZAC sequences as a preamble could be utilized in accordance with the number of transmitting antenna and channel condition. The effect of the number of CAZAC sequences for channel estimation is also presented in terms of mean square error (MSE). Taking into account the effect of multiple access interference (MAI) introduced by a symbol timing misalignment, the symbol error rate (BER) and throughput performance are investigated for a typical OFDMA uplink scenario.
Ultrafast Mid-infrared Spectroscopy of the Charge- and Spin-Ordered Nickelate La1.75Sr0.25NiO4
Coslovich G.,Huber B.,Lee W.-S.,Chuang Y.-D.
EPJ Web of Conferences , 2013, DOI: 10.1051/epjconf/20134103016
Abstract: We present the first ultrafast mid-infrared study of charge and spin-ordered nickelates. A sub-picosecond modulation of the optical reflectivity is observed, indicating the filling and subsequent re-establishment of the pseudogap in the time-domain.
A study on the CO2 laser welding characteristics of high strength steel up to 1500 MPa for automotive application
C.-H. Kim,J.-K. Choi,M.-J. Kang,Y.-D. Park
Journal of Achievements in Materials and Manufacturing Engineering , 2010,
Abstract: Purpose: This paper presents the mechanical and metallurgical characteristics of laser weldments for automotive steels with high strength ranging from 370 MPa to 1500 MPa.Design/methodology/approach: Butt joint welding was conducted on high strength steel sheets by using a CO2 laser with 6 kW output power. For sound welds with full penetration, the proper welding conditions were chosen and the cross-sectional bead shape, tensile strength, hardness profile and micro-structure were evaluated for each case.Findings: Laser welding is known to be a low heat input process because of its high heat density and welding speed. But for laser welding of ultra high strength steel with strength over 780 MPa, micro-structural softening was observed in the HAZ (heat affected zone), resulting from dissolved martensite.Practical implications: The tensile strength reduction in laser welding of ultra high strength steed should be considered in the design of car body structures. The HAZ softening that occurs in butt joint welding can reduce the tensile shear strength for overlap joint welds, which are predominantly mostly used in the BIW (body-in-white) structure.Originality/value: This paper quantitatively demonstrates the occurrence of HAZ softening and a tensile strength reduction in laser welding of automotive steel with 780 MPa strength and more.
Underestimated effects of low temperature during early growing season on carbon sequestration of a subtropical coniferous plantation
W.-J. Zhang, H.-M. Wang, F.-T. Yang, Y.-H. Yi, X.-F. Wen, X.-M. Sun, G.-R. Yu, Y.-D. Wang,J.-C. Ning
Biogeosciences (BG) & Discussions (BGD) , 2011,
Abstract: The impact of air temperature in early growing season on the carbon sequestration of a subtropical coniferous plantation was discussed through analyzing the eddy flux observations at Qianyanzhou (QYZ) site in southern China from 2003 to 2008. This site experienced two cold early growing seasons (with temperature anomalies of 2–5 °C) in 2005 and 2008, and a severe summer drought in 2003. Results indicated that the low air temperature from January to March was the major factor controlling the inter-annual variations in net carbon uptake at this site, rather than the previously thought summer drought. The accumulative air temperature from January to February showed high correlation (R2=0.970, p<0.001) with the annual net ecosystem production (NEP). This was due to the controls of early-month temperature on the plant phenology developing and the growing season length at this subtropical site. The cold spring greatly shortened the growing season length and therefore reduced the carbon uptake period. The eddy flux observations showed a carbon loss of 4.04 g C m 2 per growing-season day at this coniferous forest site. On the other hand, the summer drought also reduced the net carbon uptake strength because the photosynthesis was more sensitive to water deficit stress than the ecosystem respiration. However, the impact of summer drought occurred within a relatively shorter period and the carbon sequestration went back to the normal level once the drought was relieved.
Detection of ULF electromagnetic emissions as a precursor to an earthquake in China with an improved polarization analysis
Y. Ida, D. Yang, Q. Li, H. Sun,M. Hayakawa
Natural Hazards and Earth System Sciences (NHESS) & Discussions (NHESSD) , 2008,
Abstract: An improved analysis of polarization (as the ratio of vertical magnetic field component to the horizontal one) has been developed, and applied to the approximately four years data (from 1 March 2003 to 31 December 2006) observed at Kashi station in China. It is concluded that the polarization ratio has exhibited an apparent increase only just before the earthquake on 1 September 2003 (magnitude = 6.1 and epicentral distance of 116 km).
Fractal analysis of ULF electromagnetic emissions in possible association with earthquakes in China
Y. Ida, D. Yang, Q. Li, H. Sun,M. Hayakawa
Nonlinear Processes in Geophysics (NPG) , 2012,
Abstract: The long-term data (during the period of 1 March 2003 through 31 December 2006) of ULF geomagnetic variations observed at Kashi station (geographic coordinates: 39.5° N, 76.0° E) in China have been used to investigate the long-term variation of fractal dimension of ULF emissions. We have studied the changes in fractal dimension in association with several earthquakes around the observation station. It is then found that a significant change (or decrease) in the fractal dimension of the Z component took place before the 1 September 2003 earthquake, which lends a further support to our previous finding based on our improved polarization analysis for the same earthquake. The results obtained are discussed in the contexts of a few aspects (detectability of seismogenic emissions, comparison with previous results by other analysis methods, the importance of fractal analysis in the nonlinear process of the lithosphere and earthquake prediction).
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