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Background: Caries experience in Argentine children is quite high and no national data are present. Aim: This cross-sectional observational survey aimed to assess the oral health status of schoolchildren in Buenos Aires (CABA) using CTNI and to evaluate the ecological association between health inequalities and caries prevalence. Design: Data were collected, via a clustered procedure, during the 2016–2018 school years. Children were examined at school to determine dental status according to the CTNI performed under standardized conditions, using light, dental mirrors, WHO probes and magnification (2.5×). Secondary sources were used to acquire socio-demographic and epidemiological data. A hierarchical cluster analysis was carried out with the municipalities of the CABA as the dependent variable and the socio-demographic factors. Results: The study population consisted of 62,904 schoolchildren, 43,571 of whom were enrolled into the study. Total caries prevalence was 67.78% while severe caries prevalence was 28.29%, which was statistically associated with the year of the survey (p < 0.01). Four territorial conglomerates from a socio-epidemiological standpoint outline homogeneous areas of social risk; cluster 1 had the highest social risk. The prevalence of severe caries (CTNI 7–14) was highest in cluster 1 (44.7–53.2% of the population). Conclusion: The social inequalities between municipalities of the CABA were statistically associated with high inequalities in oral health needs.

Abstract Introduction/objectivesThe review systematically explored in vivo or in situ studies investigating the efficacy of nano-hydroxyapatite (nHA) to reduce initiation of or to remineralize initial caries lesions.DataProspective controlled (non-)randomized clinical trials investigating the efficacy of a nHA compared to any other (placebo) treatment or untreated/standard control.SourcesThree electronic databases (Central Cochrane, PubMed-MEDLINE, Ovid EMBASE) were screened. Outcomes were, e.g., ICDAS score, laser fluorescence, enamel remineralization rate, mineral loss, and lesion depth. No language or time restrictions were applied. Risk of bias and level of evidence were graded using the Risk of Bias 2.0 tool and GRADE profiler.Study selection/resultsFive in vivo (and 5 in situ) studies with at least 633 teeth (1031 specimens) being assessed in more than 420 (95) patients were included. No meta-analysis could be performed for in vivo studies due to the high heterogeneity of the study designs and the variety of outcomes. In situ studies indicate that under demineralization conditions, NaF was able to hinder demineralization, whereas nHA did not; simultaneously, nHA did not differ from the fluoride-free control. In contrast, under remineralizing conditions, nHA and NaF show the same remineralizing potential. However, the level of evidence was very low. Furthermore, six studies showed a high risk of bias, and six studies were funded/published by the manufacturers of the tested products.ConclusionThe low number of clinical studies, the relatively short follow-up periods, the high risks of bias, and the limiting grade of evidence do not allow for conclusive evidence on the efficacy of nHA.Clinical relevanceNo conclusive evidence on the efficacy of nHA could be obtained based on the low number of clinical studies, the relatively short follow-up periods, the high risks of bias, the limiting grade of evidence, and study conditions that do not reflect the everyday conditions.

Introduction Extended exposure to high-speed handpieces and other noise-intensive devices might put dentists at risk for possible hearing impairment. The aim of this study was to determine the hearing ability of dentists and other scientists for comparison. Methods After approval by the ethics committee, 115 subjects (dentists and other academic professionals as controls) of both genders were enrolled in the study. Exclusion criteria were colds, ear-blockages or abnormal hearing-thresholds. An audiometric determination (Oscilla USB audiometer, AudioConsole 3, Inmedico A/S, Denmark) was performed in the frequency range of 125Hz to 8 kHz for both ears. Anamnestic data and number of years in the profession were assessed using a questionnaire. Differences between groups were analyzed with the Mann–Whitney- U -test. Results Data from 53 dentists and 55 other academic professionals (69.4% male, 30.6% female) with a mean age of 51.7 ± 9.6 years and similar gender distributions in both groups were analyzed. The audiometric tests for the right and left air conduction showed that the hearing of dentists tended to be slightly more impaired than in the control subjects. For the frequencies 3 kHz and 4 kHz these differences were statistically significant for both ears. In contrast, no significant differences were found in this range for bone conduction. Conclusions Hearing impairment in dentists was slightly higher than in controls. Although other factors like environmental noise exposure were comparable for both groups, occupational exposure to high-speed handpieces and other noisy devices can be an additional burden for the hearing.

The Centres for Disease Control and Prevention and the World Health Organization have developed preparedness and prevention checklists for healthcare professionals regarding the containment of COVID-19. The aim of the present protocol is to evaluate the impact of the COVID-19 outbreak among dentists in different countries where various prevalence of the epidemic has been reported. Several research groups around the world were contacted by the central management team. The online anonymous survey will be conducted on a convenience sample of dentists working both in national health systems and in private or public clinics. In each country/area, a high (~5–20%) proportion of dentists working there will be invited to participate. The questionnaire, developed and standardized previously in Italy, has four domains: (1) personal data; (2) symptoms/signs relative to COVID-19; (3) working conditions and PPE (personal protective equipment) adopted after the infection’s outbreak; (4) knowledge and self-perceived risk of infection. The methodology of this international survey will include translation, pilot testing, and semantic adjustment of the questionnaire. The data will be entered on an Excel spreadsheet and quality checked. Completely anonymous data analyses will be performed by the central management team. This survey will give an insight into the dental profession during COVID-19 pandemic globally.

Fluoride ion batteries are potential \"next-generation\" electrochemical storage devices that offer high energy density. At present, such batteries are limited to operation at high temperatures because suitable fluoride ion-conducting electrolytes are known only in the solid state. We report a liquid fluoride ion-conducting electrolyte with high ionic conductivity, wide operating voltage, and robust chemical stability based on dry tetraalkylammonium fluoride salts in ether solvents. Pairing this liquid electrolyte with a copper-lanthanum trifluoride (Cu@LaF ) core-shell cathode, we demonstrate reversible fluorination and defluorination reactions in a fluoride ion electrochemical cell cycled at room temperature. Fluoride ion-mediated electrochemistry offers a pathway toward developing capacities beyond that of lithium ion technology.

Thermally evaporated C 60 is a near-ubiquitous electron transport layer in state-of-the-art p–i–n perovskite-based solar cells. As perovskite photovoltaic technologies are moving toward industrialization, batch-to-batch reproducibility of device performances becomes crucial. Here, we show that commercial as-received (99.75% pure) C 60 source materials may coalesce during repeated thermal evaporation processes, jeopardizing such reproducibility. We find that the coalescence is due to oxygen present in the initial source powder and leads to the formation of deep states within the perovskite bandgap, resulting in a systematic decrease in solar cell performance. However, further purification (through sublimation) of the C 60 to 99.95% before evaporation is found to hinder coalescence, with the associated solar cell performances being fully reproducible after repeated processing. We verify the universality of this behavior on perovskite/silicon tandem solar cells by demonstrating their open-circuit voltages and fill factors to remain at 1950 mV and 81% respectively, over eight repeated processes using the same sublimed C 60 source material. Notably, one of these cells achieved a certified power conversion efficiency of 30.9%. These findings provide insights crucial for the advancement of perovskite photovoltaic technologies towards scaled production with high process yield. Batch-to-batch reproducibility of device performances is crucial for perovskite photovoltaics moving towards industrialization. Here, the authors show that commercial as-received C 60 source materials may coalesce during repeated thermal evaporation processes, jeopardizing such reproducibility.

The global photovoltaic (PV) market is dominated by crystalline silicon (c-Si) based technologies with heavily doped, directly metallized contacts. Recombination of photo-generated electrons and holes at the contact regions is increasingly constraining the power conversion efficiencies of these devices as other performance-limiting energy losses are overcome. To move forward, c-Si PV technologies must implement alternative contacting approaches. Passivating contacts, which incorporate thin films within the contact structure that simultaneously supress recombination and promote charge-carrier selectivity, are a promising next step for the mainstream c-Si PV industry. In this work, we review the fundamental physical processes governing contact formation in c-Si. In doing so we identify the role passivating contacts play in increasing c-Si solar cell efficiencies beyond the limitations imposed by heavy doping and direct metallization. Strategies towards the implementation of passivating contacts in industrial environments are discussed. The development of passivating contacts holds great potential for enhancing the power conversion efficiency of silicon photovoltaics. Here, De Wolf et al. review recent advances in material design and device architecture, and discuss technical challenges to industrial fabrication.

Traditional Chinese medicine commands a unique position among all traditional medicines because of its 5000 years of history. Our own interest in natural products from traditional Chinese medicine was triggered in the 1990s, by artemisinin-type sesquiterpene lactones from Artemisia annua L. As demonstrated in recent years, this class of compounds has activity against malaria, cancer cells, and schistosomiasis. Interestingly, the bioactivity of artemisinin and its semisynthetic derivative artesunate is even broader and includes the inhibition of certain viruses, such as human cytomegalovirus and other members of the Herpesviridae family (e.g., herpes simplex virus type 1 and Epstein-Barr virus), hepatitis B virus, hepatitis C virus, and bovine viral diarrhea virus. Analysis of the complete profile of the pharmacological activities and molecular modes of action of artemisinin and artesunate and their performance in clinical trials will further elucidate the full antimicrobial potential of these versatile pharmacological tools from nature.

Monolithic perovskite/silicon tandem solar cells are of great appeal as they promise high power conversion efficiencies (PCEs) at affordable cost. In state-of-the-art tandems, the perovskite top cell is electrically coupled to a silicon heterojunction bottom cell by means of a self-assembled monolayer (SAM), anchored on a transparent conductive oxide (TCO), which enables efficient charge transfer between the subcells 1 – 3 . Yet reproducible, high-performance tandem solar cells require energetically homogeneous SAM coverage, which remains challenging, especially on textured silicon bottom cells. Here, we resolve this issue by using ultrathin (5-nm) amorphous indium zinc oxide (IZO) as the interconnecting TCO, exploiting its high surface-potential homogeneity resulting from the absence of crystal grains and higher density of SAM anchoring sites when compared with commonly used crystalline TCOs. Combined with optical enhancements through equally thin IZO rear electrodes and improved front contact stacks, an independently certified PCE of 32.5% was obtained, which ranks among the highest for perovskite/silicon tandems. Our ultrathin transparent contact approach reduces indium consumption by approximately 80%, which is of importance to sustainable photovoltaics manufacturing 4 . An independently certified power conversion efficiency of 32.5% for perovskite/silicon tandem solar cells is achieved through improved charge transfer at the amorphous indium zinc oxide interconnecting layer and reduced optical losses at the front and rear electrodes.

Modification of bacterial surface structures, such as the lipid A portion of lipopolysaccharide (LPS), is used by many pathogenic bacteria to help evade the host innate immune response. Helicobacter pylori, a gram-negative bacterium capable of chronic colonization of the human stomach, modifies its lipid A by removal of phosphate groups from the 1- and 4'-positions of the lipid A backbone. In this study, we identify the enzyme responsible for dephosphorylation of the lipid A 4'-phosphate group in H. pylori, Jhp1487 (LpxF). To ascertain the role these modifications play in the pathogenesis of H. pylori, we created mutants in lpxE (1-phosphatase), lpxF (4'-phosphatase) and a double lpxE/F mutant. Analysis of lipid A isolated from lpxE and lpxF mutants revealed lipid A species with a 1 or 4'-phosphate group, respectively while the double lpxE/F mutant revealed a bis-phosphorylated lipid A. Mutants lacking lpxE, lpxF, or lpxE/F show a 16, 360 and 1020 fold increase in sensitivity to the cationic antimicrobial peptide polymyxin B, respectively. Moreover, a similar loss of resistance is seen against a variety of CAMPs found in the human body including LL37, β-defensin 2, and P-113. Using a fluorescent derivative of polymyxin we demonstrate that, unlike wild type bacteria, polymyxin readily associates with the lpxE/F mutant. Presumably, the increase in the negative charge of H. pylori LPS allows for binding of the peptide to the bacterial surface. Interestingly, the action of LpxE and LpxF was shown to decrease recognition of Helicobacter LPS by the innate immune receptor, Toll-like Receptor 4. Furthermore, lpxE/F mutants were unable to colonize the gastric mucosa of C57BL/6J and C57BL/6J tlr4 -/- mice when compared to wild type H. pylori. Our results demonstrate that dephosphorylation of the lipid A domain of H. pylori LPS by LpxE and LpxF is key to its ability to colonize a mammalian host.