THE ROLE OF ARSENIC METABOLISM IN MORTALITY, DIABETES, AND KIDNEY DISEASE

Abstract Experimental and epidemiological evidence supports the role of chronic arsenic exposure in a broad scope of adverse health effects at a wide range of exposure levels. However, little is known regarding arsenic metabolism and health risk. The objective of this dissertation was to investigate the role of arsenic metabolism in mortality, diabetes, and kidney disease. First, we conducted a systematic review of the epidemiologic evidence examining the relation between arsenic metabolism and cancer, cardiovascular diseases, and adiposity. We identified 12 eligible studies for cancer, 9 for cardiovascular diseases, and 7 for adiposity. The higher proportion of monomethylarsonate [MMA%] in the urine tended to be associated with cancer and cardiovascular disease risk, whereas the lower MMA% tended to associated with an increase in adiposity. However, rather heterogeneous statistical approaches and limited prospective evidence prevented a conclusive inference from this review. In variability analysis, the range of between-population variation in MMA% is relatively narrow compared to the proportion of inorganic arsenic [iAs%] and dimethylarsinate [DMA%] in urine. Second, we measured arsenic metabolism defined by relative proportions of inorganic arsenic, MMA and DMA over their sum in the baseline urine of Strong Heart Study participants aged 45-74 years to evaluate the role of arsenic metabolism in all-cause, cardiovascular disease and cancer mortality. The adjusted hazard ratio of all-cause mortality for an interquartile increase in DMA% was 1.16 (95% CI 1.01-1.33) when it substituted iAs% whereas MMA% did not explain the risk of all-cause mortality. For cardiovascular mortality, the adjusted hazard ratio for an interquartile change increase in MMA% was 1.52 (1.16-1.99) and 1.17 (1.01-1.35) when it substituted iAs% and DMA%, respectively. For cancer mortality, the adjusted hazard ratio for an interquartile increase in MMA% was 0.73 (0.55-0.98) and 0.81 (0.67-0.97) when it substituted iAs% and DMA%, respectively. Third, we examine the prospective association between arsenic metabolism and diabetes in the Strong Heart Study. The adjusted hazard ratios of diabetes for an interquartile range increase in MMA% was 0.69 (95% CI 0.52-0.90) and 0.76 (0.65-0.89) when it was substituted for iAs% and DMA%, respectively. The association between arsenic metabolism and diabetes was similar by age, sex, study site, obesity, and the sum of inorganic and methylated arsenic concentrations. Fourth, we evaluated the role of arsenic metabolism in the development of chronic kidney disease among Strong Heart Study participants without baseline kidney disease. Incident kidney disease was defined by estimated glomerular filtration rate(eGFR) <60 ml/min/1.73m2 with a drop in eGFR ≥ 25%. The adjusted hazard ratio for an interquartile range increase in MMA% was 1.76 (95% CI 1.26-2.47) and 1.22 (1.02-1.45) when it was substituted for iAs% and DMA%, respectively. And when an interquartile range increase in DMA% with a corresponding decrease in iAs%, the adjusted hazard ratio was 1.83 (95% CI 1.29-2.61). In conclusion, arsenic metabolism was significantly associated with the risk of mortality, diabetes, and kidney disease and the associations were independent of total chronic arsenic exposure. Our results support that urine biomarkers of arsenic metabolism may reflect individual susceptibility to arsenic-related health effects and provide a novel perspective on the dynamic modeling of arsenic metabolism. In addition to replicating these finding across diverse populations and geographical areas to advance risk assessment and risk management of arsenic, future research needs to evaluate mechanisms for the connection between arsenic metabolism and health outcomes

Constructing Employability Indicators for Enhancing the Effectiveness of Engineering Education for the Solar Industry

The aim of this research is to establish a set of employability indicators that capture the competency requirements and performance expectations that solar energy enterprises have of their employees. In the qualitative component of the study, 12 administrators and 32 engineers in the industry were interviewed, and meetings with focus groups were conducted to formulate a questionnaire for a survey of Taiwanese solar energy companies for the confirmation and prioritisation of the employability indicators. On the basis of the results of the quantitative component, an interpretational model relating competence, job performance, working attitude, and employability for solar corporation recruitment and training purposes as well as for school curricular development was developed. The interpretation model formulated effectively interprets the relationship between solar enterprises’ expectations and students’ employability. The research contributes a framework for the selection and cultivation of talent, as well as providing a basis for fundamental development of the solar engineering curriculum

Effect of Na+ Flow on Cd2+ Block of Tetrodotoxin-resistant Na+ Channels

Tetrodotoxin-resistant (TTX-R) Na+ channels are 1,000-fold less sensitive to TTX than TTX-sensitive (TTX-S) Na+ channels. On the other hand, TTX-R channels are much more susceptible to external Cd2+ block than TTX-S channels. A cysteine (or serine) residue situated just next to the aspartate residue of the presumable selectivity filter “DEKA” ring of the TTX-R channel has been identified as the key ligand determining the binding affinity of both TTX and Cd2+. In this study we demonstrate that the binding affinity of Cd2+ to the TTX-R channels in neurons from dorsal root ganglia has little intrinsic voltage dependence, but is significantly influenced by the direction of Na+ current flow. In the presence of inward Na+ current, the apparent dissociation constant of Cd2+ (∼200 μM) is ∼9 times smaller than that in the presence of outward Na+ current. The Na+ flow–dependent binding affinity change of Cd2+ block is true no matter whether the direction of Na+ current is secured by asymmetrical chemical gradient (e.g., 150 mM Na+ vs. 150 mM Cs+ on different sides of the membrane, 0 mV) or by asymmetrical electrical gradient (e.g., 150 mM Na+ on both sides of the membrane, −20 mV vs. 20 mV). These findings suggest that Cd2+ is a pore blocker of TTX-R channels with its binding site located in a multiion, single-file region near the external pore mouth. Quantitative analysis of the flow dependence with the flux-coupling equation reveals that at least two Na+ ions coexist with the blocking Cd2+ ion in this pore region in the presence of 150 mM ambient Na+. Thus, the selectivity filter of the TTX-R Na+ channels in dorsal root ganglion neurons might be located in or close to a multiion single-file pore segment connected externally to a wide vestibule, a molecular feature probably shared by other voltage-gated cationic channels, such as some Ca2+ and K+ channels

Knowledge-based View in the Franchising Research Literature

Abstract. This study was conducted to understand the state of research on applications of Knowledge-based View in franchise systems. First, we used SALSA (Search, Appraisal, Synthesis, and Analysis), a simple systematic data search method, to obtain 61 sample papers. Second, the citations of authors and publications were analyzed using the bibliometric method to understand the authors and the publications that had the most impact as well as the trend of current studies in the field of knowledge-based theory application in franchise systems. The results showed that the journals that had the most publications on the topic were Entrepreneurship Theory and Practice and Journal of Business Research; the most cited author was S.A. Shane, who had an average rate of 1.016 citations per article, and the most cited study was a paper published by Darr, Argote, &amp; Epple (1995), which was cited by 18 of the 61 sample papers (18/61, 29.51%). Third, we categorized the topic of knowledge-based theory application in franchise systems into six categories, i.e., knowledge transfer, knowledge creation, knowledge sharing, knowledge application, organizational learning, and knowledge exchange, to provide references for future studies.Keywords. Knowledge-based view; Franchising; Bibliometrics.JEL. L10

Building Professional Competencies Indices in the Solar Energy Industry for the Engineering Education Curriculum

This study aims to develop professional competency indices and their subindices as needed by the solar energy industry, to establish a basis for development of the engineering education curriculum. The methodologies adopted by the study are literature analysis, expert advisories, and focus groups. The study focuses on the establishment of competency indices by experts at stock market-listed companies and then confirms these competencies with focus groups. The study found that the competencies required by the solar industry consist of knowledge, skills, and attitudes in the areas of materials development and applications, photovoltaic technology, cell manufacturing technology, biotechnology, chemical technology, power generation and electricity, process development and improvement, data collection and analysis, industry regulation, green energy beliefs, and working attitudes and values. The results of this study can be used as the basis for the cultivation, selection, and employment of industry professionals

EFFECT OF DIFFERENT TIBIA ANGLES TO LOADING OF KNEE DURING SPLIT SQUAT

The aim of this study was to investigate the difference of knee joint force and moment during split squats of different front tibia angles. Twelve healthy male college students performed six repetitions of four different split squat types with a standard additional load of 25% BW added using a barbell. Using 10 camera 3D motion capture system and a force plate to collect data. The peak force and moment of knee flexion (sagittal plane) were calculated by using self-designed MATLAB programs. One-way ANOVA test was undertaken using SPSS 20.0 statistical software. The analysis results of the study indicated that all kinetic parameters of the four types split squats were achieved high significant differences (p less than .000). A better understanding of different loading in specific joints and correct exercise execution during training will help protecting practitioners from sport injury

The wearable devices application for evaluation of 110 meter high hurdle race

Purpose: This study was intended to explore the continuous changes in the kinematic parameters of hurdlers in a 110 meter (110m) high hurdle race from hurdles 1 through 10. Method: Ten excellent college athletes who specialized in the 110m high hurdle race volunteered for this study. Inertial measurement units (IMUs) strapped to the back of the athlete’s feet and 10 high-speed cameras were used to document the movements of the hurdlers as they were hurdling along the entire track. Kwon3D and MATLAB computer programs were employed for the analysis of kinematic parameters (take-off distance, landing distance, take-off distance percentage, landing distance percentage, flight time, time between hurdles, hurdle cycle time, hurdle cycle velocity, height of centre gravity above the hurdle and take-off angles). The trend analysis was introduced to test the changes of the parameters between hurdles. The level of significance was set to α =.05. Results: The results showed that the subjects averaged 14.31±0.29 seconds in their 110m high hurdle tests. Regarding the trend analysis, all kinematic parameters except landing distance displayed quadratic linear patterns along the 110m race. Conclusion: The athletes rapidly gained speed as they sprinted from the starting line and reached their maximum speeds between hurdles 5 and 6, after which their speed declined. In addition, the kinematic parameters changed as the running velocity varied.This research was supported by the National Science Council in Taiwan (MOST 107-2410-H-033-036-)