23 research outputs found
High-fidelity simulations of CdTe vapor deposition from a new bond-order potential-based molecular dynamics method
CdTe has been a special semiconductor for constructing the lowest-cost solar
cells and the CdTe-based Cd1-xZnxTe alloy has been the leading semiconductor
for radiation detection applications. The performance currently achieved for
the materials, however, is still far below the theoretical expectations. This
is because the property-limiting nanoscale defects that are easily formed
during the growth of CdTe crystals are difficult to explore in experiments.
Here we demonstrate the capability of a bond order potential-based molecular
dynamics method for predicting the crystalline growth of CdTe films during
vapor deposition simulations. Such a method may begin to enable defects
generated during vapor deposition of CdTe crystals to be accurately explored
Defect formation dynamics during CdTe overlayer growth
The presence of atomic-scale defects at multilayer interfaces significantly
degrades performance in CdTe-based photovoltaic technologies. The ability to
accurately predict and understand defect formation mechanisms during overlayer
growth is, therefore, a rational approach for improving the efficiencies of
CdTe materials. In this work, we utilize a recently developed CdTe bond-order
potential (BOP) to enable accurate molecular dynamics (MD) simulations for
predicting defect formation during multilayer growth. A detailed comparison of
our MD simulations to high-resolution transmission electron microscopy
experiments verifies the accuracy and predictive power of our approach. Our
simulations further indicate that island growth can reduce the lattice mismatch
induced defects. These results highlight the use of predictive MD simulations
to gain new insight on defect reduction in CdTe overlayers, which directly
addresses efforts to improve these materials
Shared heritability and functional enrichment across six solid cancers
Correction: Nature Communications 10 (2019): art. 4386 DOI: 10.1038/s41467-019-12095-8Quantifying the genetic correlation between cancers can provide important insights into the mechanisms driving cancer etiology. Using genome-wide association study summary statistics across six cancer types based on a total of 296,215 cases and 301,319 controls of European ancestry, here we estimate the pair-wise genetic correlations between breast, colorectal, head/neck, lung, ovary and prostate cancer, and between cancers and 38 other diseases. We observed statistically significant genetic correlations between lung and head/neck cancer (r(g) = 0.57, p = 4.6 x 10(-8)), breast and ovarian cancer (r(g) = 0.24, p = 7 x 10(-5)), breast and lung cancer (r(g) = 0.18, p = 1.5 x 10(-6)) and breast and colorectal cancer (r(g) = 0.15, p = 1.1 x 10(-4)). We also found that multiple cancers are genetically correlated with non-cancer traits including smoking, psychiatric diseases and metabolic characteristics. Functional enrichment analysis revealed a significant excess contribution of conserved and regulatory regions to cancer heritability. Our comprehensive analysis of cross-cancer heritability suggests that solid tumors arising across tissues share in part a common germline genetic basis.Peer reviewe
Shared heritability and functional enrichment across six solid cancers
Quantifying the genetic correlation between cancers can provide important insights into the mechanisms driving cancer etiology. Using genome-wide association study summary statistics across six cancer types based on a total of 296,215 cases and 301,319 controls of European ancestry, here we estimate the pair-wise genetic correlations between breast, colorectal, head/neck, lung, ovary and prostate cancer, and between cancers and 38 other diseases. We observed statistically significant genetic correlations between lung and head/neck cancer (r(g) = 0.57, p = 4.6 x 10(-8)), breast and ovarian cancer (r(g) = 0.24, p = 7 x 10(-5)), breast and lung cancer (r(g) = 0.18, p = 1.5 x 10(-6)) and breast and colorectal cancer (r(g) = 0.15, p = 1.1 x 10(-4)). We also found that multiple cancers are genetically correlated with non-cancer traits including smoking, psychiatric diseases and metabolic characteristics. Functional enrichment analysis revealed a significant excess contribution of conserved and regulatory regions to cancer heritability. Our comprehensive analysis of cross-cancer heritability suggests that solid tumors arising across tissues share in part a common germline genetic basis
Youth in Transition: Life Skills Among Perinatally HIV-Infected and HIV-Exposed Adolescents
Self-organized surface nanopatterns on Cd(Zn)Te crystals induced by medium-energy ion beam sputtering
Spatial and temporal variations in airborne particulate matter (PM10 and PM2.5) across Spain 1999–2005
Average ranges of particulate matter (PM10 and PM2.5) concentrations and chemical composition in Spain show significant variations across the country, with current PM10 levels at several industrial and traffic hotspots exceeding recommended pollution limits. Such variations and exceedances are linked to patterns of anthropogenic and natural PM emissions, climate, and reactivity/stability of particulate species. PM10 and PM2.5 concentrations reach 14–22 μg PM10 m−3 and 8–12 μg PM2.5 m−3 at most rural/regional background sites, 25–30 μg PM10 m−3 and 15–20μg PM2.5 m−3 at suburban sites, 30–46 μg PM10 m−3 and 20–30 μg PM2.5 m−3 at urban background and industrial sites, and 46–50 μg PM10 m−3 and 30–35 μg PM2.5 m−3 at heavy traffic hotpots. Spatial distributions show sulphate and carbon particle levels reach maxima in industrialised areas and large cities (where traffic emissions are higher), and nitrate levels increase from the Atlantic to the Mediterranean (independent of the regional NOx emissions). African dust outbreaks have an influence on the number of exceedances of the daily limit value, but its additional load on the mean annual PM10 levels is only highly significant in Southern Iberia and Canary and Balearic islands. The marine aerosol contribution is near one order of magnitude higher in the Canaries compared to the other regions. Important temporal influences include PM intrusion events from Africa (more abundant in February–March and spring–summer), regional-scale pollution episodes, and weekday versus weekend activity. Higher summer insolation enhances (NH4)2SO4 but depletes particulate NO3− (as a consequence of the thermal instability of ammonium nitrate in summer) and Cl− (due to HCl volatilisation resulting from the interaction of gaseous HNO3 with the marine NaCl), as well as generally increasing dry dust resuspension under a semi-arid climate. Average trace metal concentrations rise with the highest levels at industrial and traffic hotspots sites, in some cases (Ti, Cr, Mn, Cu, Zn, As, Sn, W, and Pb) exceeding rural background levels by over an order of magnitude