Mapping Charge Distribution in Single PbS Core - CdS Arm Nano-Multipod Heterostructures by Off-Axis Electron Holography.

We synthesized PbS core-CdS arm nanomultipod heterostructures (NMHs) that exhibit PbS{111}/CdS{0002} epitaxial relations. The PbS-CdS interface is chemically sharp as determined by aberration corrected transmission electron microscopy (TEM) and compared to density functional theory (DFT) calculations. Ensemble fluorescence measurements show quenching of the optical signal from the CdS arms indicating charge separation due to the heterojunction with PbS. A finite-element three-dimensional (3D) calculation of the Poisson equation shows a type-I heterojunction, which would prevent recombination in the CdS arm after optical excitation. To examine charge redistribution, we used off-axis electron holography (OAEH) in the TEM to map the electrostatic potential across an individual heterojunction. Indeed, a built-in potential of 500 mV is estimated across the junction, though as opposed to the thermal equilibrium calculations significant accumulation of positive charge at the CdS side of the interface is detected. We conclude that the NMH multipod geometry prevents efficient removal of generated charge carriers by the high energy electrons of the TEM. Simulations of generated electron-hole pairs in the insulated CdS arm of the NMH indeed show charge accumulation in agreement with the experimental measurements. Thus, we show that OAEH can be used as a complementary methodology to ensemble measurements by mapping the charge distribution in single NMHs with complex geometries.

Dog bite Emergency department presentations in Brisbane metro south: Epidemiology and exploratory medical geography for targeted interventions.

Dog bites are a recognized public health issue due to their impact on human and animal health/welfare. This study aimed to investigate demographic and geographic disparities in the epidemiology of dog bites presentations reported to the emergency departments of the four main public hospitals in the Metro South region of Brisbane, Queensland, Australia. Dog bite patient hospitalization data geolocated to the street address were collected from clinical records management systems from the four main public hospitals in the Metro South Hospital Health Service region of Queensland for a 5-year period (ie. 01/07/2013 to 30/06/2017). We investigated the epidemiology of three clinical outcomes including probability of paediatric cases (paediatric vs. adult), probability of dog bites to the head (head injury vs. other injury), and probability of re-presentation to the ED following their initial dog bite (yes or no) by way of univariable then multivariable Bernoulli logistic regression models including patient postcode as a random effect. Residual semivariograms were created to identify spatial trends in the medical geography of dog bites and binomial geostatistical models were created to predict the probability of the outcomes of interest in Brisbane Metro south and surrounding suburbs. Our results demonstrate that compared to adult dog bite cases, paediatric dog bite cases were significantly associated with bites to the head or face or neck (OR 14.65, P < 0.001), bites to the lower body (OR 4.95, P = 0.035) and larger dogs (OR 0.25, P = 0.030 for small dogs). The probability of head injuries was greater in younger age groups (17-39 OR 0.25, P = 0.001; 40-64 OR 0.15, P = 0.001; 65-above OR 0.14, P = 0.029). Attacks by small dogs were more likely to inflict head wounds than large dogs (OR 6.12, P < 0.001). The probability of re-presentation was lower in patients bitten by medium sized dogs (OR 0.29, P = 0.027) than larger dogs. Our predictive maps showed significant clustering of paediatric case probability in the Logan city and Redlands councils associated with socioeconomic status of the places of residence. In conclusion, our findings demonstrate significant demographic and geographic heterogeneity in dog bite ED presentations. Public health interventions to reduce the burden of dog bites should be targeted to the populations most at-risk in the areas identified in this study.

Geographical variation in the risk of H7N9 human infections in China: implications for risk-based surveillance.

The influenza A (H7N9) subtype remains a public health problem in China affecting individuals in contact with live poultry, particularly at live bird markets. Despite enhanced surveillance and biosecurity at LBMs H7N9 viruses are now more widespread in China. This study aims to quantify the temporal relationship between poultry surveillance results and the onset of human H7N9 infections during 2013-2017 and to estimate risk factors associated with geographical risk of H7N9 human infections in counties in Southeast China. Our results suggest that poultry surveillance data can potentially be used as early warning indicators for human H7N9 notifications. Furthermore, we found that human H7N9 incidence at county-level was significantly associated with the presence of wholesale LBMs, the density of retail LBMs, the presence of poultry virological positives, poultry movements from high-risk areas, as well as chicken population density and human population density. The results of this study can influence the current AI H7N9 control program by supporting the integration of poultry surveillance data with human H7N9 notifications as an early warning of the timing and areas at risk for human infection. The findings also highlight areas in China where monitoring of poultry movement and poultry infections could be prioritized.