Assessment of thermal and fast reactor designs based upon the advance gas-cooled reactor

Imperial Users onl

Diabetes and kidney cancer: A direct or indirect association?

A positive association between diabetes and kidney cancer has been reported in several investigations, but it is unclear whether diabetes or its complications account for this association. Recent advances in estimating direct associations may be useful for elucidating the association between diabetes and kidney cancer. Therefore, we performed a case-control analysis to evaluate whether the direct association between diabetes and kidney cancer is the primary concern in this exposure-outcome relation. Discharge data (with International Classification of Diseases – 9 codes) from 2001 for hospitals throughout Florida were used to construct a case-control population of inpatients aged ≥45 years. Cases (n=1,909) were inpatients with malignant kidney cancer and controls (n=6,451) were inpatients with motor vehicle injuries. Diabetes status was ascertained for cases and controls. Covariates that required adjustment to estimate the total (age, gender, ethnicity, obesity, and smoking) and direct (age, gender, ethnicity, obesity, smoking, hypertension, and kidney disease) associations were identified in a directed acyclic graph. Binary logistic regression was used to estimate the adjusted total and direct odds ratios (ORs) and corresponding 95% confidence intervals (CIs) of kidney cancer for diabetics. The odds of kidney cancer were higher for inpatients with diabetes than inpatients without diabetes when estimating the total association (OR=1.27, 95%CI: 1.10, 1.47) but attenuated when estimating the direct association (OR=1.08, 95%CI: 0.93, 1.25). Our findings provide preliminary insight that the direct association between diabetes and kidney cancer may not be the primary concern in this exposure-outcome relation; indirect pathways (i.e. diabetic complications) may have greater influence on this relation. A similar analysis using longitudinal data with appropriately measured covariates may provide more definitive conclusions and could have implications for kidney cancer prevention among diabetics

ATOMIC LAYER DEPOSITION OF ALKALI PHOSPHORUS OXYNITRIDE ELECTROLYTES FOR BEYOND-LITHIUM NANOSCALE BATTERIES

Lithium-ion batteries dominate portable energy storage systems today due to their light weight and high performance. However, with the continuing demand for battery capacity projected to outstrip the supply of lithium, alternative energy storage systems based on the more abundant Na and K alkali metals are attractive from both a resource perspective and their similar charge storage mechanism. Beyond limited lithium resources, there remains significant opportunity for innovation to improve battery architecture and thus performance. Nanostructured solid-state batteries (SSBs) are poised to meet the demands of next-generation energy storage technologies, with atomic layer deposition (ALD) being a powerful tool enabling high-performance nanostructured SSBs that offer competitive performance with their liquid-based counterparts. This dissertation has two main objectives: First, the development of the first reported ALD solid-state Na+ and K+ conductors are presented. Second, by leveraging the work on developing new solid- state Na+ ion conductors, a proof-of-principle nanoscale Na-SSB is fabricated and tested.ALD processes are developed for the Na and K based analogues of the well-known solid- state electrolyte (SSE) lithium phosphorus oxynitride (LiPON). In this case; NaPON and KPON. A comprehensive comparison of the structure, electrochemical, and processing parameters between the APON (A = Li, Na, K) family of materials is presented. The structure of NaPON closely resembles that of ALD LiPON, both possessing a N/P of 1, classifying them as alkali polyphosphazenes. Interestingly, KPON exhibits similar ALD process parameters to NaPON and LiPON, but the resulting film composition is quite different, showing little nitrogen incorporation and more closely resembling a phosphate glass. NaPON is determined to be a promising SSE with an ionic conductivity of 1.0 ́ 10-7 S/cm at 25 °C and a wide electrochemical stability window of 0-6.0V vs. Na/Na+. The electrochemical stability and performance of NaPON as a SSE is tested in liquid-based and all solid-state battery configurations comprised of a V2O5 cathode and Na metal anode. Electrochemical analysis suggests intermixing of the NaPON/V2O5 layers during the ALD NaPON deposition, and further reaction during the Na metal evaporation step. The reaction during the ALD NaPON deposition on V2O5 is determined to be two-fold: (1) reduction of V2O5 to VO2 and (2) Na+ insertion into VO2 to form NaxVO2. The Na metal evaporation process is found to exacerbate this reactivity, resulting in the formation of irreversible interphases leading to poor SSB performance. Despite the relatively poor performance, this work represents the first report of a nanoscale Na-SSB and showcases cryo- TEM as a powerful characterization technique to further the understanding of nanoscale SSBs. Looking forward, the intermixing during the ALD NaPON deposition does not impact the cycling of the NaxVO2 electrode in liquid-based cells, with NaPON-coated electrodes outperforming unsodiated V2O5 electrodes. This may be advantageous for the fabrication of SSBs, as the SSE deposition simultaneously could pre-sodiate a stable cathode material, excluding the need for ex-situ sodiation in liquid solutions or depositing a pre-sodiated electrode material. Strategies to pair this NaxVO2/NaPON cathode/electrolyte with a stable anode are discussed, with a focus on the ultimate realization of a high-performance Na-SSB. This work highlights the high reactivity of Na compared to Li based battery chemistries, not only necessitating the need for interfacial coatings in Na SSBs, but also the extreme caution required during fabrication of Na-SSBs or liquid sodium- ion batteries

Blood Lead Concentrations in 1–3 Year Old Lebanese Children: A Cross-sectional study

BACKGROUND: Childhood lead poisoning has not made the list of national public health priorities in Lebanon. This study aims at identifying the prevalence and risk factors for elevated blood lead concentrations (B-Pb ≥ 100 μg/L) among 1–3 year old children. It also examines the need for universal blood lead screening. METHODS: This is a cross-sectional study of 281 well children, presenting to the pediatric ambulatory services at the American University of Beirut Medical Center in 1997–98. Blood was drawn on participating children for lead analysis and a structured questionnaire was introduced to mothers asking about social, demographic, and residence characteristics, as well as potential risk factors for lead exposure. Children with B-Pb ≥ 100 μg/L were compared to those with B-Pb < 100 μg/L. RESULTS: Mean B-Pb was 66.0 μg/L (median 60.0; range 10–160; standard deviation 26.3) with 39 (14%) children with B-Pb ≥ 100 μg/L. Logistic regression analysis showed that elevated B-Pb was associated with paternal manual jobs (odds ratio [OR]: 4.74), residence being located in high traffic areas (OR: 4.59), summer season (OR: 4.39), using hot tap water for cooking (OR: 3.96), exposure to kohl (OR: 2.40), and living in older buildings (OR: 2.01). CONCLUSION: Lead screening should be offered to high-risk children. With the recent ban of leaded gasoline in Lebanon, emphasis should shift to other sources of exposure in children

Study of hysteretic thermoelectric behavior in photovoltaic materials using the finite element method, extended thermodynamics and inverse problems

The main objective of the present work is to develop and prove a theoretical explanation based on the Extended Non-Equilibrium Thermodynamics (ENETs) for the hysteretical thermoelectric behavior observed in certain thin-film photovoltaic materials. The ENET introduces dissipative fluxes in the entropy balance that could explain this behavior. To verify this explanation from a numerical point of view, results are generated using a Finite Element (FE) formulation based on the ENET and already developed in previous publications by the authors. In addition, an identification Inverse Problem (IP) is formulated; a cost function is defined as the quadratic difference between experimental and numerical results and the IP is solved minimizing the cost function using genetic algorithms. The conclusion is that the loop-like distributions are due to energy dissipation introduced by dissipative fluxes that are closely related with relaxation times. Also, the FE-IP combination permits to find an approximated characterization of properties for several materials from single experimental curves. Finally, several numerical simulations are proposed for laboratory experiments to further validate the theoretical interpretation and to confirm the relation between relaxation times and hysteresis.This research was partially supported by the Grants CSD2008-00037 Canfranc Underground Physics, Excelencia Junta Andalucia P08-TEP-03641 and Polytechnic University of Valencia under programs PAID 02-11-1828 and 05-10-2674.Palma, R.; Pérez-Aparicio, JL.; Bravo, R. (2013). Study of hysteretic thermoelectric behavior in photovoltaic materials using the finite element method, extended thermodynamics and inverse problems. Energy Conversion and Management. 65(92):557-563. https://doi.org/10.1016/j.enconman.2012.07.009S557563659

Schools of Public Health in Low and Middle-Income Countries: An Imperative Investment for Improving the Health of Populations?

BACKGROUND: Public health has multicultural origins. By the close of the nineteenth century, Schools of Public Health (SPHs) began to emerge in western countries in response to major contemporary public health challenges. The Flexner Report (1910) emphasized the centrality of preventive medicine, sanitation, and public health measures in health professional education. The Alma Ata Declaration on Primary Health Care (PHC) in 1978 was a critical milestone, especially for low and middle-income countries (LMICs), conceptualizing a close working relationship between PHC and public health measures. The Commission on Social Determinants of Health (2005-2008) strengthened the case for SPHs in LMICs as key stakeholders in efforts to reduce global health inequities. This scoping review groups text into public health challenges faced by LMICs and the role of SPHs in addressing these challenges. MAIN TEXT: The challenges faced by LMICs include rapid urbanization, environmental degradation, unfair terms of global trade, limited capacity for equitable growth, mass displacements associated with conflicts and natural disasters, and universal health coverage. Poor governance and externally imposed donor policies and agendas, further strain the fragile health systems of LMICs faced with epidemiological transition. Moreover barriers to education and research imposed by limited resources, political and economic instability, and unbalanced partnerships additionally aggravate the crisis. To address these contextual challenges effectively, SPHs are offering broad based health professional education, conducting multidisciplinary population based research and fostering collaborative partnerships. SPHs are also looked upon as the key drivers to achieve sustainable development goals (SDGs). CONCLUSION: SPHs in LMICs can contribute to overcoming several public health challenges being faced by LMICs, including achieving SDGs. Most importantly they can develop cadres of competent and well-motivated public health professionals: educators, practitioners and researchers who ask questions that address fundamental health determinants, seek solutions as agents of change within their mandates, provide specific services and serve as advocates for multilevel partnerships. Funding support, human resources, and agency are unfortunately often limited or curtailed in LMICs, and this requires constructive collaboration between LMICs and counterpart institutions from high income countries

Schools of public health in low and middle-income countries: an imperative investment for improving the health of populations?

BACKGROUND: Public health has multicultural origins. By the close of the nineteenth century, Schools of Public Health (SPHs) began to emerge in western countries in response to major contemporary public health challenges. The Flexner Report (1910) emphasized the centrality of preventive medicine, sanitation, and public health measures in health professional education. The Alma Ata Declaration on Primary Health Care (PHC) in 1978 was a critical milestone, especially for low and middle-income countries (LMICs), conceptualizing a close working relationship between PHC and public health measures. The Commission on Social Determinants of Health (2005-2008) strengthened the case for SPHs in LMICs as key stakeholders in efforts to reduce global health inequities. This scoping review groups text into public health challenges faced by LMICs and the role of SPHs in addressing these challenges. MAIN TEXT: The challenges faced by LMICs include rapid urbanization, environmental degradation, unfair terms of global trade, limited capacity for equitable growth, mass displacements associated with conflicts and natural disasters, and universal health coverage. Poor governance and externally imposed donor policies and agendas, further strain the fragile health systems of LMICs faced with epidemiological transition. Moreover barriers to education and research imposed by limited resources, political and economic instability, and unbalanced partnerships additionally aggravate the crisis. To address these contextual challenges effectively, SPHs are offering broad based health professional education, conducting multidisciplinary population based research and fostering collaborative partnerships. SPHs are also looked upon as the key drivers to achieve sustainable development goals (SDGs). CONCLUSION: SPHs in LMICs can contribute to overcoming several public health challenges being faced by LMICs, including achieving SDGs. Most importantly they can develop cadres of competent and well-motivated public health professionals: educators, practitioners and researchers who ask questions that address fundamental health determinants, seek solutions as agents of change within their mandates, provide specific services and serve as advocates for multilevel partnerships. Funding support, human resources, and agency are unfortunately often limited or curtailed in LMICs, and this requires constructive collaboration between LMICs and counterpart institutions from high income countries