174 research outputs found
Electrolytes and Interphases in Sodium-Based Rechargeable Batteries: Recent Advances and Perspectives
For sodium (Na)-rechargeable batteries to compete, and go beyond the currently prevailing Li-ion technologies, mastering the chemistry and accompanying phenomena is of supreme importance. Among the crucial components of the battery system, the electrolyte, which bridges the highly polarized positive and negative electrode materials, is arguably the most critical and indispensable of all. The electrolyte dictates the interfacial chemistry of the battery and the overall performance, having an influence over the practical capacity, rate capability (power), chemical/thermal stress (safety), and lifetime. In-depth knowledge of electrolyte properties provides invaluable information to improve the design, assembly, and operation of the battery. Thus, the full-scale appraisal of both tailored electrolytes and the concomitant interphases generated at the electrodes need to be prioritized. The deployment of large-format Na-based rechargeable batteries also necessitates systematic evaluation and detailed appraisal of the safety-related hazards of Na-based batteries. Hence, this review presents a comprehensive account of the progress, status, and prospect of various Na+-ion electrolytes, including solvents, salts and additives, their interphases and potential hazards
Environmental changes and the rise and fall of civilizations in the northern Horn of Africa: an approach combining δD analyses of land-plant derived fatty acids with multiple proxies in soil
International audienceThe domains of the ancient polities D'MT and Aksum in the Horn of Africa's highlands are a superior natural system for evaluating roles of environmental change on the rise and fall of civilizations. To compare environmental changes of the times of the two polities, we analyzed stable hydrogen isotopic ratios (δD) of land-plant derived fatty acids (n-C26-30) and other proxies from soil sequences spanning the Holocene from the region. Three results suggest that trends in δD values unambiguously reflect changes in rainfall. First, increases in δD coincide with dry periods inferred from studies of eastern African lakes. Second, changes in δD values were parallel among sections during overlapping time intervals. Third, consideration of vegetation history did not alter directions of trends in δD values over time. By unambiguously recording precipitation, the δD values also enhanced interpretations of proxies that are affected by both climate and land clearing. Both D'MT (ca 2750-2350 cal y BP) and the Aksumite (ca 2100-1250 cal y BP) rose during wetter intervals of the drier part of the Holocene (after ca 6000 cal y BP). Analyses of charred matter indicated that fire had been a common agent of land clearing in all sites. The influence of climate on fire varied, however. Prior to the emergence of D'MT, δD values were correlated with C4:C3 plant ratios estimated from δ13C values. There are no C4 trees and precipitation may have been the main influence on canopy openness. After ca 4300 cal y BP, there was no significant relationship between δD and C4:C3 plant ratios suggesting that factors such as fire influenced canopy openness regardless of climate. Furthermore, the impact of land clearance differed between sites and between D'MT and the Aksumite's times. In one site, the interval from 3550 cal y BP to the decline of D'MT had several anomalies that suggested dramatic increases in thermal severity of fire and human impact. Among these were a large contribution of charred matter to a high% total organic carbon that low hydrogen and oxygen indices suggest was severely altered by other factors than humification. These results support hypotheses about the rise of civilizations being favored by specific climatic conditions but suggest that patterns of land clearing differed during the declines of D'MT and the Aksumite
Chemical exchange saturation transfer MRI in central nervous system tumours on a 1.5 T MR-Linac
Purpose: To describe the implementation and initial results of using Chemical Exchange Saturation Transfer (CEST) for monitoring patients with central nervous system (CNS) tumours treated using a 1.5 tesla MR-guided radiotherapy system. Methods: CNS patients were treated with up to 30 fractions (total dose up to 60 Gy) using a 1.5 T Elekta Unity MR-Linac. CEST scans were obtained in 54 subjects at one or more time points during treatment. CEST metrics, including the amide magnetization transfer ratio (MTRAmide), nuclear Overhauser effect (NOE) MTR (MTRNOE) and asymmetry, were quantified in phantoms and CNS patients. The signal was investigated between tumour and white matter, across time, and across disease categories including high- and low-grade tumours. Results: The gross tumour volume (GTV) exhibited lower MTRAmide and MTRNOE and higher asymmetry compared to contralateral normal appearing white matter. Signal changes in the GTV during fractionated radiotherapy were observed. There were differences between high- and low-grade tumours, with higher CEST asymmetry associated with higher grade disease. Conclusion: CEST MRI using a 1.5 T MR-Linac was demonstrated to be feasible for in vivo imaging of CNS tumours. CEST images showed tumour/white-matter contrast, temporal CEST signal changes, and associations with tumour grade. These results show promise for the eventual goal of using metabolic imaging to inform the design of adaptive radiotherapy protocols
Survival Benefit for Individuals With Constitutional Mismatch Repair Deficiency Undergoing Surveillance
PURPOSE: Constitutional mismatch repair deficiency syndrome (CMMRD) is a lethal cancer predisposition syndrome characterized by early-onset synchronous and metachronous multiorgan tumors. We designed a surveillance protocol for early tumor detection in these individuals. PATIENTS AND METHODS: Data were collected from patients with confirmed CMMRD who were registered in the International Replication Repair Deficiency Consortium. Tumor spectrum, efficacy of the surveillance protocol, and malignant transformation of low-grade lesions were examined for the entire cohort. Survival outcomes were analyzed for patients followed prospectively from the time of surveillance implementation. RESULTS: A total of 193 malignant tumors in 110 patients were identified. Median age of first cancer diagnosis was 9.2 years (range: 1.7-39.5 years). For patients undergoing surveillance, all GI and other solid tumors, and 75% of brain cancers were detected asymptomatically. By contrast, only 16% of hematologic malignancies were detected asymptomatically (P \u3c .001). Eighty-nine patients were followed prospectively and used for survival analysis. Five-year overall survival (OS) was 90% (95% CI, 78.6 to 100) and 50% (95% CI, 39.2 to 63.7) when cancer was detected asymptomatically and symptomatically, respectively (P = .001). Patient outcome measured by adherence to the surveillance protocol revealed 4-year OS of 79% (95% CI, 54.8 to 90.9) for patients undergoing full surveillance, 55% (95% CI, 28.5 to 74.5) for partial surveillance, and 15% (95% CI, 5.2 to 28.8) for those not under surveillance (P \u3c .0001). Of the 64 low-grade tumors detected, the cumulative likelihood of transformation from low-to high-grade was 81% for GI cancers within 8 years and 100% for gliomas in 6 years. CONCLUSION: Surveillance and early cancer detection are associated with improved OS for individuals with CMMRD
Etiquette of the antibiotic decision-making process for surgical prophylaxis in Ethiopia: a triangulated ethnographic study
BackgroundProphylactic antibiotics reduce surgery-associated infections and healthcare costs. While quantitative methods have been widely used to evaluate antibiotic use practices in surgical wards, they fall short of fully capturing the intricacies of antibiotic decision-making in these settings. Qualitative methods can bridge this gap by delving into the often-overlooked healthcare customs that shape antibiotic prescribing practices.AimThis study aimed to explore the etiquette of the antibiotic decision-making process of surgical prophylaxis antibiotic use at Tikur Anbessa Specialized Hospital (TASH).MethodsThe observational study was carried out at TASH, a teaching and referral hospital in Addis Ababa, Ethiopia, from 26 August 2021 to 1 January 2022. Overall, 21 business ward rounds, 30 medical record reviews, and 11 face-to-face interviews were performed sequentially to triangulate and cross-validate the qualitative observation. The data were collected until saturation. The data were cleaned, coded, summarized, and analyzed using the thematic analysis approach.ResultSurgical antibiotic prophylaxis (SAP) discussions were infrequent during surgical ward rounds in TASH, leading to practices that deviated from established recommendations. Clear documentation differentiating SAP from other antibiotic uses was also lacking, which contributed to unjustified extended SAP use in the postoperative period. Missed SAP documentation was common for emergency surgeries, as well as initial dose timing and pre-operative metronidazole administration. Importantly, there was no standardized facility guideline or clinical protocol for SAP use. Furthermore, SAP prescriptions were often signed by junior residents and medical interns, and administration was typically handled by anesthesiologists/anesthetists at the operating theater and by nurses in the wards. This suggests a delegation of SAP decision-making from surgeons to senior residents, then to junior residents, and finally to medical interns. Moreover, there was no adequate representation from pharmacy, nursing, and other staff during ward rounds.ConclusionDeeply ingrained customs hinder evidence-based SAP decisions, leading to suboptimal practices and increased surgical site infection risks. Engaging SAP care services and implementing antimicrobial stewardship practices could optimize SAP usage and mitigate SSI risks
AIDS knowledge and attitudes in a Turkish population: an epidemiological study
BACKGROUND: The aim of this study was to investigate and present some pertinent comments concerning Acquired Immunodeficiency Syndrome (AIDS) knowledge, attitudes and misconceptions among the general population in a city of west Turkey. This study was deemed important and relevant due to the increasing importance of AIDS in Turkey and the other countries. METHODS: Using a multistage area sampling method, a random sample of individuals aged 11–83 years, living in 65 different quarters in the city of Eskisehir, Turkey during September, October and November 2004 were interviewed. RESULTS: In all, 1048 respondents completed the survey. In most items, respondents displayed a fairly good to excellent degree of knowledge about HIV/AIDS. Individuals with higher degrees of education indicated more correct responses in all items relating to knowledge of HIV/AIDS. In general, the respondents' attitudes towards AIDS and people with AIDS were found to be tolerant and positive, with one answer choice showing that the majority of the respondents agreed with the statement that those with HIV/AIDS must be supported, treated and helped (90.7%). Moreover, the proportions of the respondents' misconceptions were found to be significantly low for all the items. However, nearly one fourth of the respondents agreed with the misconceptions 'AIDS is a punishment by God' and 'One is not infected with HIV/AIDS if engaged in sport and well nourished'. CONCLUSION: In general HIV/AIDS related knowledge was high and people showed positive attitudes. However, people continue to hold misconceptions about AIDS and these need to be addressed by health education programs targeting those at higher risk
Detection and Molecular Characterization of 9000-Year-Old Mycobacterium tuberculosis from a Neolithic Settlement in the Eastern Mediterranean
Background: Mycobacterium tuberculosis is the principal etiologic agent of human tuberculosis. It has no environmental reservoir and is believed to have co-evolved with its host over millennia. This is supported by skeletal evidence of the disease in early humans, and inferred from M. tuberculosis genomic analysis. Direct examination of ancient human remains for M. tuberculosis biomarkers should aid our understanding of the nature of prehistoric tuberculosis and the host/pathogen relationship.Methodology/Principal Findings: We used conventional PCR to examine bone samples with typical tuberculosis lesions from a woman and infant, who were buried together in the now submerged site of Atlit-Yam in the Eastern Mediterranean, dating from 9250-8160 years ago. Rigorous precautions were taken to prevent contamination, and independent centers were used to confirm authenticity of findings. DNA from five M. tuberculosis genetic loci was detected and had characteristics consistent with extant genetic lineages. High performance liquid chromatography was used as an independent method of verification and it directly detected mycolic acid lipid biomarkers, specific for the M. tuberculosis complex.Conclusions/Significance: Human tuberculosis was confirmed by morphological and molecular methods in a population living in one of the first villages with evidence of agriculture and animal domestication. The widespread use of animals was not a source of infection but may have supported a denser human population that facilitated transmission of the tubercle bacillus. The similarity of the M. tuberculosis genetic signature with those of today gives support to the theory of a long-term co-existence of host and pathogen
Healable Cellulose Iontronic Hydrogel Stickers for Sustainable Electronics on Paper
The authors acknowledge the support from FCT - Portuguese Foundation for Science and Technology through the Ph.D. scholarships SFRH/BD/126409/2016 (I.C.) and SFRH/BD/122286/2016 (J.M.). The authors would like to acknowledge the European Commission under project NewFun (ERC-StG-2014, GA 640598) and project SYNERGY (H2020-WIDESPREAD-2020-5, CSA, proposal no 952169). This work was also supported by the FEDER funds through the COMPETE 2020 Program and the National Funds through the FCT - Portuguese Foundation for Science and Technology under the Project No. POCI-01-0145-FEDER-007688, reference UID/CTM/50025, project CHIHC, reference PTDC/NAN-MAT/32558/2017. The authors would also like to thank their colleagues Daniela Gomes and Ana Pimentel from CENIMAT/i3N for the SEM and DSC-TGA measurements, respectively.Novel nature-based engineered functional materials combined with sustainable and economically efficient processes are among the great challenges for the future of mankind. In this context, this work presents a new generation of versatile flexible and highly conformable regenerated cellulose hydrogel electrolytes with high ionic conductivity and self-healing ability, capable of being (re)used in electrical and electrochemical devices. They can be provided in the form of stickers and easily applied as gate dielectric onto flexible indium–gallium–zinc oxide transistors, decreasing the manufacturing complexity. Flexible and low-voltage (<2.5 V) circuits can be handwritten on-demand on paper transistors for patterning of conductive/resistive lines. This user-friendly and simplified manufacturing approach holds potential for fast production of low-cost, portable, disposable/recyclable, and low-power ion-controlled electronics on paper, making it attractive for application in sensors and concepts such as the “Internet-on-Things.”.publishersversionpublishe
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