Use Of Computed Tomography-Based Nomogram In Adult Age Patients To Predict Success Rates After Shock Wave Lithotripsy For Renal Stones: A Single Center Experience.

BACKGROUND: The Triple D score is a novel and easy to use nomogram to predict shock-wave lithotripsy (SWL) outcomes. It is based on Computed Tomography (CT scan) parameters including stone density, skin-to-stone distance, and stone volume. However, its use has not been validated much as studies are sparse regarding its use. Our aim was to validate and evaluate accuracy of the Triple D scoring system in predicting SWL success rates. METHODS: It was a prospective study of 277 patients who had undergone SWL procedure for renal stones. They were evaluated by using non-contrast tomography, before undergoing SWL. CT scan-based parameters including distance of stone to skin (SSD), stone volume (SV), stone density was assessed. Computation of Cut off values was done with receiver operating characteristics analysis. Score was assigned on the basis of these cut-off values and success rate of SWL was determined. This score ranged from 0 (least favourable score) to 3 (most favourable score). RESULTS: Stone-free status was attained in 160 patients (57.7%), and 117 (42.3%) patients were labelled to have failed the procedure. Differences between these two groups in terms of Stone volume, stone density and skin to stone distance were significant. Triple D scores of zero,1, 2, and 3 had stone-free rates of 3.6%, 52.56%, 53.3%, and 93.1% respectively (p-vaue<0.001). CONCLUSIONS: Shock-wave lithotripsy outcomes can be predicted with use of Triple D score and hence, it's externally corroborated. It may help urologist in appropriate patient selection and hence decision making and patient counselling.

The marvelous optical performance of AlGaN-based deep ultraviolet light-emitting diodes with AlInGaN-based last quantum barrier and step electron blocking layer.

The optoelectronic characteristics of AlGaN-based deep ultraviolet light-emitting diodes (DUV LEDs) with quaternary last quantum barrier (QLQB) and step-graded electron blocking layer (EBL) are investigated numerically. The results show that the internal quantum efficiency (IQE) and radiative recombination rate are remarkably improved with AlInGaN step-graded EBL and QLQB as compared to conventional or ternary AlGaN EBL and last quantum barrier (LQB). This significant improvement is assigned to the optimal recombination of electron-hole pairs in the multiple quantum wells (MQWs). It is due to the decrease in strain and lattice mismatch between the epi-layers which alleviates the effective potential barrier height of the conduction band and suppressed the electron leakage without affecting the holes transportation to the active region. Moreover, to figure out quantitatively, the electron and hole quantity increased by ~ 25% and ~ 15%, respectively. Additionally, the IQE and radiative recombination rate are enhanced by 48% and 55%, respectively, as compared to conventional LED. So, we believe that our proposed structure is not only a feasible approach for achieving highly efficient DUV LEDs, but the device physics presented in this study establishes a fruitful understanding of III nitride-based optoelectronic devices.

Suppressing the efficiency droop in AlGaN-based UVB LEDs.

The optoelectronic properties of semiconducting aluminum gallium nitride (AlGaN)-based ultraviolet-B (UVB) light-emitting diodes (LEDs) are crucial for real-world medical applications such as cancer therapy and immunotherapy. However, the performance of AlGaN-based UVB LED devices is still poor due to the low hole injection efficiency. Therefore, we have numerically investigated the performance of AlGaN-based UVB LEDs for the suppression of efficiency droop as well as for the enhancement of hole injection in the multiquantum wells (MQWs). The influence of the undoped (ud)-AlGaN final quantum barrier (FQB), as well as the Mg-doped multiquantum barrier electron blocking layer (p-MQB EBL), on the efficiency droop has been focused on specifically. To evaluate the performance of the proposed device, we have compared its internal quantum efficiency (IQE), carrier concentration, energy band diagram, and radiative recombination rate with the conventional device structure. Furthermore, the influence of Al composition in the Al-graded p-AlGaN hole source layer (HSL) on the operating voltages of the proposed UVB LEDs was considered. The simulation results suggest that our proposed structure has a high peak efficiency and much lower efficiency droop as compared to the reference structure (conventional). Ultimately, the radiative recombination rate in the MQWs of the proposed UVB LED-N structure has increased up to ∼73%, which is attributed to the enhanced level of electron and hole concentrations by ∼64% and 13%, respectively, in the active region. Finally, a high efficiency droop of up to ∼42% in RLED has been successfully suppressed, to ∼7%, by using the optimized ud-AlGaN FQB and the p-MQB EBL, as well as introducing Al-graded p-AlGaN HSL in the proposed UVB LED-N structure.

Suppressing the efficiency droop in the AlGaN-based UVB LED.

Optoelectronic properties of semiconducting aluminum gallium nitride (AlGaN) - based ultraviolet - B (UVB) light-emitting diodes (LEDs) are crucial for the real-world medical applications such as cancer and immunotherapy. Therefore, we have numerically investigated the performances of AlGaN-based UVB LEDs for the suppression of efficiency droop as well as for the enhancement of hole injection in the multiquantum wells (MQWs). The influence of the undoped (ud)-AlGaN final barrier (FB) as well as Mg-doped multiquantum barrier electron blocking layer (p-MQB EBL) on the efficiency droop has been specifically focused. For the evaluation of the proposed device performance, we have compared its internal quantum efficiency (IQE), carrier concentration, energy band diagram, and radiative recombination rate with the conventional device structure. Furthermore, the influence of Al-composition in the p-AlGaN hole source layer (HSL) on the operating voltages of the proposed UVB LEDs was considered. The simulation results suggest that our proposed structure has high peak efficiency and much lower efficiency droop as compared to the reference structure (conventional). Ultimately, the radiative recombination rate in the MQWs of the proposed structure has been found to raise up to ~73%, which is attributed to the enhanced level of electron and hole concentrations by ~64% and 13% , respectively, in the active region. Finally, a high efficiency droop up to ~42% in RLED has been found successfully suppressed to ~7% by using optimized ud-AlGaN FB and p-MQB EBL in the proposed UVB device structure.

AlGaN-based ultraviolet light-emitting diodes: challenges and opportunities.

Due to low power consumption, tunable wavelength and long lifetime ultraviolet light-emitting diodes (UV LEDs) have found many applications in different fields such as health care, water disinfection, agriculture. In this review, we report different problems that lead to low external quantum efficiency of UV LEDs. We also report various challenges in the growth process of the UV LEDs such as increase in the dislocation density, which affects the optoelectronic performance of the devices. We also report the analysis of the two modes of light polarization, i.e. transverse electric and transverse magnetic in UV LEDs. Moreover, we also summarize various state-of-the-art reported external quantum efficiencies, light output power and peak emission wavelengths in the three UV wavelength regimes, i.e. UV-A, UV-B and UV-C LEDs.

Workplace bullying in risk and safety professionals.

INTRODUCTION: Previous research demonstrates that workplace bullying impacts the welfare of victimized employees, with further consequences for the organization and profession. There is, however, a paucity of information relating to the bullying directed at risk and safety professionals. The present study was conducted to address this issue. METHOD: Risk and safety professionals (N=420) completed the Negative Acts Questionnaire - Revised and Brief Cope, and reported the extent to which they had been pressured to make or amend a risk or safety based decision. RESULTS: Those experiencing workplace bullying were more likely to engage in a range of coping behaviors, with exposure to work-related and personal bullying particularly influential. Workplace bullying also predicted pressure to make or change a risk or safety based decision. Work related and physically intimidating bullying were particularly important for this aspect of professional practice. CONCLUSIONS: Findings are discussed with regard to current practice and the support available to risk and safety professionals. PRACTICAL APPLICATIONS: Risk and safety professionals require additional support in relation to workplace bullying and specifically guidance to resist pressure to make or change a risk or safety based decision.