DC 81

In 2019, there were nearly 50,000 opioid-related deaths in the US, with substantial variation across sociodemographic groups and geography. To systematically investigate patterns of racial/ethnic inequities in opioid-related mortality, we used joinpoint regression models to estimate the trajectory of the opioid epidemic among non-Hispanic Black versus non-Hispanic white residents in Washington DC, 45 states, and 81 sub-state areas. We highlight the unique inequities observed in Washington DC. In 2019, the observed opioid-related mortality rate among Black DC residents was 11.3 times higher than white DC residents, resulting in 56.0 more deaths per 100,000 (61.5 vs. 5.5 per 100,000). This inequity was substantially higher than any other jurisdiction on both the relative and absolute scales. Most opioid-related deaths in DC involved synthetic opioids, which was present in 92% (N=198) of deaths among Black DC residents and 69% (N=11) of deaths among white DC residents. Localized, equitable, culturally-appropriate, targeted interventions are necessary to reduce the uniquely disproportionate burden of opioid-related mortality among Black DC residents. Supplementary Information: The online version contains supplementary material available at 10.1007/s11524-021-00573-8.

The aim of this study was to determine the frequency and severity of dental fluorosis (DF) and the association between severity and risk factors. In a cross-sectional study, 8- to 12-year-old children, born in a Colombian district, were evaluated according to the Thylstrup and Fejerskov Index (TFI) by two calibrated examiners. Molar Incisor Hypomineralization (MIH) and dental caries (DC) were also evaluated. Ordinal logistic regression was applied (p<0.05). Risk factors and lifestyle factors were collected using a questionnaire answered by parents. DF was detected in 76 (98.7%) of the children (average of 18.4 ±1.81 permanent teeth affected). Grade TF2 was the most frequently observed (34.8%); TF5 was observed in all age groups; TF6- TF7 were observed in 12-year-olds. No association was found between DF severity and DC (Odds Ratio (OR)=1.35; 95%CI: 0.56-3.26) or MIH (OR=1.39; 95%CI: 0.43-4.46). DF severity was significantly associated with use of an indoor wood stove for food preparation (OR = 9.34; 95%CI: 1.11-78.57) and use of a pea-sized volume of toothpaste (OR = 27.42; 95%CI: 1.57-477.36). Prevalence of DC was 38.1% and prevalence of MIH was 14.4%. In this population, the frequency of DF was high and severity was associated with use of an indoor wood stove for food preparation and toothpaste amount used during childhood.

The technology of modern power systems is revolutionizing as renewable energy sources are being integrated with electric power grids. In the form of inverters, power electronic converters are becoming an integral part of power systems due to their massive demand for grid integration of photovoltaic (PV) systems. Existing multilevel inverter topologies either require an output filter to get a sinusoidal voltage or generate a higher number of output voltage levels at the expense of many hardware resources. This paper presents a new single-phase 81-level inverter configuration with the name given as 'Modified W-Type Multilevel Inverter'. The proposed inverter configuration uses only eighteen power switches and four DC voltage sources to generate an 81-level output voltage approaching a sinusoidal waveform without an output filter. The general design equations are developed to calculate the number of switches, the number of voltage levels, and the number of DC sources for the proposed configuration. Loss and efficiency analysis is carried out that verifies a good practical efficiency of the proposed inverter configuration during the dynamic operation. A comparative analysis with the existing MLI topologies is also carried out that validates the effectiveness and novelty in reducing parts count and higher number of voltage levels. The proposed topology offers 1.04% total harmonic distortion of the output voltage which is within the benchmarks specified for grid integration without any filter requirements. The proposed inverter configuration is simulated in MATLAB/Simulink, and the results are validated by the design and development of a hardware prototype.