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Search Results: 1 - 10 of 130136 matches for " Yu-Chieh Chen "
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Influencing Factors and Improvement Strategies for Indoor Air Quality and Human Thermal Comfort in a Convenience Store  [PDF]
Yu-Chieh Chen, Shih-Yu Chang, Chung-Hao Cheng, Chin-Ching Wu
Health (Health) , 2018, DOI: 10.4236/health.2018.102018
Abstract: Indoor air quality has received increased attention. Surveying human thermal comfort and evaluating indoor airflow and ventilation can improve the integrity assessment of the indoor environment. In this study, indoor air quality measurements and spatial assessments were performed in a convenience store on a campus. The computational fluid dynamics model was used to simulate the indoor airflow and explore the spatial distribution of the CO2 concentration. The results showed the CO2 concentration easily surpassed the standard value during the weekdays and accumulated in short flows and dead zones. In the condition of no-building alterations, the preferred improvement strategy is to modify the air supply angle to 30°.
University Student Sample Is Unable to Accurately Assess Their Calorie Needs: Implications for Weight Management and Menu Labeling  [PDF]
Yu-Chieh Chen, Debra B. Reed, Natalia Velikova, Shu Wang
Food and Nutrition Sciences (FNS) , 2012, DOI: 10.4236/fns.2012.34071
Abstract: National surveys have shown that over 80% of adults do not know their recommended calorie levels. Lack of knowledge about calorie needs could be contributing to the high prevalence of obesity in the US. Young adulthood is a crucial period for the development of dietary behaviors that continue into later adulthood and influence the risk of obesity and chronic disease. This study examined university students’ knowledge of their recommended calorie needs. Subjects (N = 153) were students at Texas Tech University in Fall 2010. Students were given a survey to assess perceived daily calorie need (PDCN) and perceived daily calorie intake (PDCI). Their recommended daily calorie needs (RDCN) and actual calorie intakes (ACI) were determined using MyPyramid.gov. PDCN, PDCI, RDCN, and ACI were compared to determine students’ ability to accurately estimate and consume recommended daily calorie levels. The range of their PDCN was 120 kcal to 10,000 kcal. Only 19.7% of students estimated their RDCN accurately. There were significant differences between PDCN and RDCN (t [152] = ?3.223, P = 0.002); PDCI and ACI (t [114] = 3.246, P = 0.002); and ACI and RDCN (t [114] = ?5.6, P = 0.000). Nearly 40% of these university students were overweight. BMI had a significant effect (P = 0.001) on students’ estimation of their RDCN as students with underweight/normal BMI were more accurate. Nutrition education programs focused on calorie needs should be implemented with university students so they will be able to effectively use calorie information on food labels and menus for weight management.
Quantification Bias Caused by Plasmid DNA Conformation in Quantitative Real-Time PCR Assay
Chih-Hui Lin, Yu-Chieh Chen, Tzu-Ming Pan
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0029101
Abstract: Quantitative real-time PCR (qPCR) is the gold standard for the quantification of specific nucleic acid sequences. However, a serious concern has been revealed in a recent report: supercoiled plasmid standards cause significant over-estimation in qPCR quantification. In this study, we investigated the effect of plasmid DNA conformation on the quantification of DNA and the efficiency of qPCR. Our results suggest that plasmid DNA conformation has significant impact on the accuracy of absolute quantification by qPCR. DNA standard curves shifted significantly among plasmid standards with different DNA conformations. Moreover, the choice of DNA measurement method and plasmid DNA conformation may also contribute to the measurement error of DNA standard curves. Due to the multiple effects of plasmid DNA conformation on the accuracy of qPCR, efforts should be made to assure the highest consistency of plasmid standards for qPCR. Thus, we suggest that the conformation, preparation, quantification, purification, handling, and storage of standard plasmid DNA should be described and defined in the Minimum Information for Publication of Quantitative Real-Time PCR Experiments (MIQE) to assure the reproducibility and accuracy of qPCR absolute quantification.
Determination of Fragmentation Schemes and Metabolites of Fluorinated Histone Deacetylase Inhibitors for Use as Positron Emission Tomography Imaging Agents Using HPLC-MS/MS  [PDF]
Wei-Hsi Chen, Yu-Chieh Hsiao, Ming-Hsin Li, Mu-Chen Tsai, Chun-Fang Feng, Han-Chih Chang, Hung-Wen Yu, Chyng-Yann Shiue
International Journal of Analytical Mass Spectrometry and Chromatography (IJAMSC) , 2018, DOI: 10.4236/ijamsc.2018.61001
Abstract: High performance liquid chromatography coupled with tandem mass spectrometry was developed and validated as a method for the analysis of fluorinated histone deacetylase inhibitors (F-HDACi), and then employed to study their metabolism in biosystems. Four HDACi analogs labeled with the positron emission nuclide 18F constitute a group of potential positron emission tomography imaging agents, which were developed by the Institute of Nuclear Energy Research (INER) and coded as INER-1577 #1, #2, #3, and #4 during animal studies for the diagnosis of dementia. The performance of the method was found to be suitable for the determination of analog #3, and it was employed to determine the structures and fragmentation mechanisms of all four analogs and to study the biotransformations of analogs #3 and #4. The results indicated that the method used for the determination of analog #3 was suitable for determining the abundance of the analogs in chemical and biochemical tests with high precision, accuracy, reproducibility, and recovery. Weaknesses in the chemical bonding of the analogs were found to involve the fluoro, dimethylamino, and benzamide groups in a fragmentation mechanism deduced via tandem mass spectrometry. The metabolites of analogs #3 and #4 in rat liver microsomes and rat plasma were also identified to clarify their characteristic behaviors in biosystems. The major product of analogs #3 in liver microsomes was produced by hydroxylation of the benzylic carbon atom, but in rat plasma the metabolites of analog #3 were produced by hydrolysis of the benzamide group to give a diaminobiphenyl compound with the simultaneous replacement of a fluorine atom by a hydroxyl group. The metabolites of analog #4 in liver microsomes were produced by hydroxylation of the benzylic carbon atom and hydrolysis of the benzamide bond. The results of the studies characterized the chemical and biochemical behaviors of the series F-HADCi analogs.
Chronic Kidney Disease Itself Is a Causal Risk Factor for Stroke beyond Traditional Cardiovascular Risk Factors: A Nationwide Cohort Study in Taiwan
Yi-Chun Chen, Yu-Chieh Su, Ching-Chih Lee, Yung-Sung Huang, Shang-Jyh Hwang
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0036332
Abstract: Background Cardiovascular disease (CVD) is a leading cause of mortality and morbidity in patients with chronic kidney disease (CKD). In Taiwan, CVD is dominated by strokes but there is no robust evidence for a causal relationship between CKD and stroke. This study aimed to explore such causal association. Methods We conducted a nationwide retrospective cohort study based on the Taiwan National Health Insurance Research Database from 2004 to 2007. Each patient identified was individually tracked for a full three years from the index admission to identify those in whom any type of stroke developed. The study cohort consisted of patients hospitalized with a principal diagnosis of CKD and no traditional cardiovascular risk factors at baseline (n = 1393) and an age-matched control cohort of patients hospitalized for appendectomies (n = 1393, a surrogate for the general population). Cox proportional hazard regression and propensity score model were used to compare the three-year stroke-free survival rate of the two cohorts after adjustment for possible confounding factors. Results There were 256 stroke patients, 156 (11.2%) in the study cohort and 100 (7.2%) in the control cohort. After adjusting for covariates, patients with primary CKD had a 1.94-fold greater risk for stroke (95% CI, 1.45–2.60; p<0.001) based on Cox regression and a 1.68-fold greater risk for stroke (95% CI, 1.25–2.25; p = 0.001) based on propensity score. This was still the case for two cohorts younger than 75 years old and without traditional cardiovascular risk factors. Conclusions This study of Taiwanese patients indicates that CKD itself is a causal risk factor for stroke beyond the traditional cardiovascular risk factors. Primary CKD patients have higher risk for stroke than the general population and all CKD patients, irrespective of the presence or severity of traditional cardiovascular risk factors, should be made aware of the stroke risk and monitored for stroke prevention.
Roles of Melatonin in Fetal Programming in Compromised Pregnancies
Yu-Chieh Chen,Jiunn-Ming Sheen,Miao-Meng Tiao,You-Lin Tain,Li-Tung Huang
International Journal of Molecular Sciences , 2013, DOI: 10.3390/ijms14035380
Abstract: Compromised pregnancies such as those associated with gestational diabetes mellitus, intrauterine growth retardation, preeclampsia, maternal undernutrition, and maternal stress may negatively affect fetal development. Such pregnancies may induce oxidative stress to the fetus and alter fetal development through the epigenetic process that may affect development at a later stage. Melatonin is an oxidant scavenger that reverses oxidative stress during the prenatal period. Moreover, the role of melatonin in epigenetic modifications in the field of developmental programming has been studied extensively. Here, we describe the physiological function of melatonin in pregnancy and discuss the roles of melatonin in fetal programming in compromised pregnancies, focusing on its involvement in redox and epigenetic mechanisms.
Pros and Cons of the Tuberculosis Drugome Approach – An Empirical Analysis
Feng-Chi Chen, Yu-Chieh Liao, Jie-Mao Huang, Chieh-Hua Lin, Yih-Yuan Chen, Horng-Yunn Dou, Chao Agnes Hsiung
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0100829
Abstract: Drug-resistant Mycobacterium tuberculosis (MTB), the causative pathogen of tuberculosis (TB), has become a serious threat to global public health. Yet the development of novel drugs against MTB has been lagging. One potentially powerful approach to drug development is computation-aided repositioning of current drugs. However, the effectiveness of this approach has rarely been examined. Here we select the “TB drugome” approach – a protein structure-based method for drug repositioning for tuberculosis treatment – to (1) experimentally validate the efficacy of the identified drug candidates for inhibiting MTB growth, and (2) computationally examine how consistently drug candidates are prioritized, considering changes in input data. Twenty three drugs in the TB drugome were tested. Of them, only two drugs (tamoxifen and 4-hydroxytamoxifen) effectively suppressed MTB growth at relatively high concentrations. Both drugs significantly enhanced the inhibitory effects of three first-line anti-TB drugs (rifampin, isoniazid, and ethambutol). However, tamoxifen is not a top-listed drug in the TB drugome, and 4-hydroxytamoxifen is not approved for use in humans. Computational re-examination of the TB drugome indicated that the rankings were subject to technical and data-related biases. Thus, although our results support the effectiveness of the TB drugome approach for identifying drugs that can potentially be repositioned for stand-alone applications or for combination treatments for TB, the approach requires further refinements via incorporation of additional biological information. Our findings can also be extended to other structure-based drug repositioning methods.
Impact of Young Age on the Prognosis for Oral Cancer: A Population-Based Study in Taiwan
Ting-Shou Chang, Chun-Ming Chang, Hsu-Chieh Ho, Yu-Chieh Su, Li-Fu Chen, Pesus Chou, Ching-Chih Lee
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0075855
Abstract: Background Oral cancer leads to a considerable use of health care resources. Wide resection of the tumor and reconstruction with a pedicle flap/ free flap is widely used. This study was conducted to investigate if young age at the time of diagnosis of oral cancer requiring this treatment confers a worse prognosis. Methods A total of 2339 patients who underwent resections for oral cancer from 2004 to 2005 were identified from The Taiwan National Health Insurance Research Database. Survival analysis, Cox proportional regression model, propensity scores, and sensitivity test were used to evaluate the association between 5-year survival rates and age. Results In the Cox proportional regression model, the older age group (>65 years) had the worst survival rate (hazard ratio [HR], 1.80; 95% confidence interval [CI], 1.45-2.22; P<0.001). When analyzed using the propensity scores, the adjusted 5-year survival rates were also poorer for oral cancer patients with older age (>65 years), compared to those with younger age (<45 years) (P<0.001). In sensitivity test, the adjusted hazard ratio remained no statistically elevated in the younger age group (<45 years). Conclusions For those oral cancer patients who underwent wide excision and reconstruction, young age did not confer a worse prognosis using a Cox proportional regression model, propensity scores or sensitivity test. Young oral cancer patients may be treated using general guidelines and do not require more aggressive treatment.
Lapatinib Induces Autophagy, Apoptosis and Megakaryocytic Differentiation in Chronic Myelogenous Leukemia K562 Cells
Huey-Lan Huang, Yu-Chieh Chen, Yu-Chuen Huang, Kai-Chien Yang, Hsin yi Pan, Shou-Ping Shih, Yu-Jen Chen
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0029014
Abstract: Lapatinib is an oral, small-molecule, dual tyrosine kinase inhibitor of epidermal growth factor receptors (EGFR, or ErbB/Her) in solid tumors. Little is known about the effect of lapatinib on leukemia. Using human chronic myelogenous leukemia (CML) K562 cells as an experimental model, we found that lapatinib simultaneously induced morphological changes resembling apoptosis, autophagy, and megakaryocytic differentiation. Lapatinib-induced apoptosis was accompanied by a decrease in mitochondrial transmembrane potential and was attenuated by the pancaspase inhibitor z-VAD-fmk, indicating a mitochondria-mediated and caspase-dependent pathway. Lapatinib-induced autophagic cell death was verified by LC3-II conversion, and upregulation of Beclin-1. Further, autophagy inhibitor 3-methyladenine as well as autophagy-related proteins Beclin-1 (ATG6), ATG7, and ATG5 shRNA knockdown rescued the cells from lapatinib-induced growth inhibition. A moderate number of lapatinib-treated K562 cells exhibited features of megakaryocytic differentiation. In summary, lapatinib inhibited viability and induced multiple cellular events including apoptosis, autophagic cell death, and megakaryocytic differentiation in human CML K562 cells. This distinct activity of lapatinib against CML cells suggests potential for lapatinib as a therapeutic agent for treatment of CML. Further validation of lapatinib activity in vivo is warranted.
Diagnostic Value of I-131 NP-59 SPECT/CT Scintigraphy in Patients with Subclinical or Atypical Features of Primary Aldosteronism
Yi-Chun Chen,Yu-Chieh Su,Chang-Kuo Wei,Jainn-Shiun Chiu,Chih-En Tseng,Shao-Jer Chen,Yuh-Feng Wang
Journal of Biomedicine and Biotechnology , 2011, DOI: 10.1155/2011/209787
Abstract: Accumulating evidence has shown the adverse effect of long-term hyperaldosteronism on cardiovascular morbidity that is independent of blood pressure. However, the diagnosis of primary aldosteronism (PA) remains a challenge for patients who present with subtle or atypical features or have chronic kidney disease (CKD). SPECT/CT has proven valuable in the diagnosis of a number of conditions. The aim of this study was to determine the usefulness of I-131 NP-59 SPECT/CT in patients with atypical presentations of PA and in those with CKD. The records of 15 patients with PA were retrospectively analyzed. NP-59 SPECT/CT was able to identify adrenal lesion(s) in CKD patients with suspected PA. Patients using NP-59 SPECT/CT imaging, compared with those not performing this procedure, significantly featured nearly normal serum potassium levels, normal aldosterone-renin ratio, and smaller adrenal size on CT and pathological examination and tended to feature stage 1 hypertension and non-suppressed plasma renin activity. These findings show that noninvasive NP-59 SPECT/CT is a useful tool for diagnosis in patients with subclinical or atypical features of PA and those with CKD.
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