44 research outputs found

    Discovery and structural assignment of (S)-sydosine from amphipod-derived Aspergillus sydowii MBC15-11F through HRMS, advanced Mosher, and molecular modelling analyses

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    AimsThis study aims to prioritize fungal strains recovered from under-explored habitats that produce new metabolites. HRMS dereplication is used to avoid structure redundancy, and molecular modelling is used to assign absolute configuration.Methods and resultsMBC15-11F was isolated from an amphipod and identified using ITS, 28S, and β-tubulin phylogeny as Aspergillus sydowii. Chemical profiling using taxonomic-based dereplication identified structurally diverse metabolites, including unreported ones. Large-scale fermentation led to the discovery of a new N-acyl adenosine derivative: (S)-sydosine (1) which was elucidated by NMR and HRESIMS analyses. Two known compounds were also identified as predicted by the initial dereplication process. Due to scarcity of 1, molecular modelling was used to assign its absolute configuration without hydrolysis, and is supported by advanced Mosher derivatization. When the isolated compounds were assessed against a panel of bacterial pathogens, only phenamide (3) showed anti-Staphylococcus aureus activity.ConclusionFermentation of A. sydowii yielded a new (S)-sydosine and known metabolites as predicted by HRESIMS-aided dereplication. Molecular modelling prediction of the absolute configuration of 1 agreed with advanced Mosher analysis

    Dihydrophenazine:a multifunctional new weapon that kills multidrug-resistant Acinetobacter baumannii and restores carbapenem and oxidative stress susceptibilities

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    AimsThe current work aims to fully characterize a new antimicrobial agent against Acinetobacter baumannii, which continues to represent a growing threat to healthcare settings worldwide. With minimal treatment options due to the extensive spread of resistance to almost all the available antimicrobials, the hunt for new antimicrobial agents is a high priority. Methods and resultsAn Egyptian soil-derived bacterium strain NHM-077B proved to be a promising source for a new antimicrobial agent. Bioguided fractionation of the culture supernatants of NHM-077B followed by chemical structure elucidation identified the active antimicrobial agent as 1-hydroxy phenazine. Chemical synthesis yielded more derivatives, including dihydrophenazine (DHP), which proved to be the most potent against A. baumannii, yet it exhibited a safe cytotoxicity profile against human skin fibroblasts. Proteomics analysis of the cells treated with DHP revealed multiple proteins with altered expression that could be correlated to the observed phenotypes and potential mechanism of the antimicrobial action of DHP. DHP is a multi-pronged agent that affects membrane integrity, increases susceptibility to oxidative stress, interferes with amino acids/protein synthesis, and modulates virulence-related proteins. Interestingly, DHP in sub-inhibitory concentrations resensitizes the highly virulent carbapenem-resistant A. baumannii strain AB5075 to carbapenems providing great hope in regaining some of the benefits of this important class of antibiotics. ConclusionsThis work underscores the potential of DHP as a promising new agent with multifunctional roles as both a classical and non-conventional antimicrobial agent that is urgently needed.<br/

    Higher-dose sitagliptin and the risk of congestive heart failure in older adults with CKD

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    Background and objectives Sitagliptin, a dipeptidylpeptidase-4 inhibitor, is commonlyprescribed to patientswith type 2 diabetes. As this drug is primarily eliminated by the kidney, a reduced dose is recommended for patients with CKD. Some evidence suggests that sitagliptin is associated with a higher risk of congestive heart failure, particularly at higher doses.Wecompare the 1-year risk of death or hospitalizationwith congestive heart failure in patients with CKD newly prescribed sitagliptin at \u3c50 versus ≤50 mg/d. Design, setting, participants, & measurements This population-based cohort study included older adults (\u3e66 years) with type 2 diabetes and an eGFR\u3c45 ml/min per 1.73 m2 (but not receiving dialysis) who were newly prescribed sitagliptin between 2010 and 2017 in Ontario, Canada. We used inverse probability of treatment weighting on the basis of propensity scores to balance baseline characteristics. The primary composite outcome was death or hospitalization with congestive heart failure. Secondary outcomes included hospitalization with pancreatitis or hypoglycemia, all-cause hospitalization, and glycemic control. Weighted hazard ratios were obtained using Cox proportional hazards regression, and 95%confidence intervalswere obtained using bootstrap variance estimators. Results Of 9215 patients, 6518 started sitagliptin at \u3e50 mg/d, and 2697 started sitagliptin at ≤50 mg/d. The 1-year risk of death or hospitalization with congestive heart failure did not differ significantly between groups (79 versus 126 events per 1000 person-years; weighted hazard ratio, 0.88; 95% confidence interval, 0.67 to 1.14); hospitalization with pancreatitis (weighted hazard ratio, 0.98; 95% confidence interval, 0.32 to 3.03) and hypoglycemia (weighted hazard ratio, 1.10; 95% confidence interval, 0.64 to 1.90) also did not differ significantly between groups. Patients starting sitagliptin at \u3e50 mg/d had lower mean glycated hemoglobin concentrations (weighted between-group difference, 20.12%; 95% confidence interval, 20.19 to 20.06) and a lower risk of allcause hospitalization (weighted hazard ratio, 0.81; 95% confidence interval, 0.66 to 0.98). Conclusions The risk of death or congestive heart failure was not higher in older adults with CKD starting sitagliptin at \u3e50 versus ≤50 mg/d

    Global incidence, prevalence, years lived with disability (YLDs), disability-adjusted life-years (DALYs), and healthy life expectancy (HALE) for 371 diseases and injuries in 204 countries and territories and 811 subnational locations, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021

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    Background: Detailed, comprehensive, and timely reporting on population health by underlying causes of disability and premature death is crucial to understanding and responding to complex patterns of disease and injury burden over time and across age groups, sexes, and locations. The availability of disease burden estimates can promote evidence-based interventions that enable public health researchers, policy makers, and other professionals to implement strategies that can mitigate diseases. It can also facilitate more rigorous monitoring of progress towards national and international health targets, such as the Sustainable Development Goals. For three decades, the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) has filled that need. A global network of collaborators contributed to the production of GBD 2021 by providing, reviewing, and analysing all available data. GBD estimates are updated routinely with additional data and refined analytical methods. GBD 2021 presents, for the first time, estimates of health loss due to the COVID-19 pandemic. Methods: The GBD 2021 disease and injury burden analysis estimated years lived with disability (YLDs), years of life lost (YLLs), disability-adjusted life-years (DALYs), and healthy life expectancy (HALE) for 371 diseases and injuries using 100 983 data sources. Data were extracted from vital registration systems, verbal autopsies, censuses, household surveys, disease-specific registries, health service contact data, and other sources. YLDs were calculated by multiplying cause-age-sex-location-year-specific prevalence of sequelae by their respective disability weights, for each disease and injury. YLLs were calculated by multiplying cause-age-sex-location-year-specific deaths by the standard life expectancy at the age that death occurred. DALYs were calculated by summing YLDs and YLLs. HALE estimates were produced using YLDs per capita and age-specific mortality rates by location, age, sex, year, and cause. 95% uncertainty intervals (UIs) were generated for all final estimates as the 2·5th and 97·5th percentiles values of 500 draws. Uncertainty was propagated at each step of the estimation process. Counts and age-standardised rates were calculated globally, for seven super-regions, 21 regions, 204 countries and territories (including 21 countries with subnational locations), and 811 subnational locations, from 1990 to 2021. Here we report data for 2010 to 2021 to highlight trends in disease burden over the past decade and through the first 2 years of the COVID-19 pandemic. Findings: Global DALYs increased from 2·63 billion (95% UI 2·44–2·85) in 2010 to 2·88 billion (2·64–3·15) in 2021 for all causes combined. Much of this increase in the number of DALYs was due to population growth and ageing, as indicated by a decrease in global age-standardised all-cause DALY rates of 14·2% (95% UI 10·7–17·3) between 2010 and 2019. Notably, however, this decrease in rates reversed during the first 2 years of the COVID-19 pandemic, with increases in global age-standardised all-cause DALY rates since 2019 of 4·1% (1·8–6·3) in 2020 and 7·2% (4·7–10·0) in 2021. In 2021, COVID-19 was the leading cause of DALYs globally (212·0 million [198·0–234·5] DALYs), followed by ischaemic heart disease (188·3 million [176·7–198·3]), neonatal disorders (186·3 million [162·3–214·9]), and stroke (160·4 million [148·0–171·7]). However, notable health gains were seen among other leading communicable, maternal, neonatal, and nutritional (CMNN) diseases. Globally between 2010 and 2021, the age-standardised DALY rates for HIV/AIDS decreased by 47·8% (43·3–51·7) and for diarrhoeal diseases decreased by 47·0% (39·9–52·9). Non-communicable diseases contributed 1·73 billion (95% UI 1·54–1·94) DALYs in 2021, with a decrease in age-standardised DALY rates since 2010 of 6·4% (95% UI 3·5–9·5). Between 2010 and 2021, among the 25 leading Level 3 causes, age-standardised DALY rates increased most substantially for anxiety disorders (16·7% [14·0–19·8]), depressive disorders (16·4% [11·9–21·3]), and diabetes (14·0% [10·0–17·4]). Age-standardised DALY rates due to injuries decreased globally by 24·0% (20·7–27·2) between 2010 and 2021, although improvements were not uniform across locations, ages, and sexes. Globally, HALE at birth improved slightly, from 61·3 years (58·6–63·6) in 2010 to 62·2 years (59·4–64·7) in 2021. However, despite this overall increase, HALE decreased by 2·2% (1·6–2·9) between 2019 and 2021. Interpretation: Putting the COVID-19 pandemic in the context of a mutually exclusive and collectively exhaustive list of causes of health loss is crucial to understanding its impact and ensuring that health funding and policy address needs at both local and global levels through cost-effective and evidence-based interventions. A global epidemiological transition remains underway. Our findings suggest that prioritising non-communicable disease prevention and treatment policies, as well as strengthening health systems, continues to be crucially important. The progress on reducing the burden of CMNN diseases must not stall; although global trends are improving, the burden of CMNN diseases remains unacceptably high. Evidence-based interventions will help save the lives of young children and mothers and improve the overall health and economic conditions of societies across the world. Governments and multilateral organisations should prioritise pandemic preparedness planning alongside efforts to reduce the burden of diseases and injuries that will strain resources in the coming decades. Funding: Bill &amp; Melinda Gates Foundation

    Flexible working and unpaid overtime in the UK: The role of gender, parental and occupational status

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    Recent studies have shown that flexible boundaries between work and family may make employees work harder and longer. Yet most studies were not able to show whether there are differences across different types of flexible working arrangements, and whether this relationship may only hold for certain groups of workers. We examine how three different types of flexible working arrangements, that is schedule control, flexitime, and teleworking, are associated with an increase in unpaid overtime hours of workers in the UK using the Understanding Society data from 2010-2015 and fixed effects panel regression models. Results show that the flexible arrangements that were introduced primarily for work-life balance purposes, i.e., flexitime and teleworking, do not necessarily increase unpaid overtime hours significantly. On the other hand, workers’ control over their schedule, mainly introduced as a part of high-performance strategies, leads to increased unpaid overtime hours. This is especially true for professional men, and women without children, especially those working full-time, and surprisingly part-time working mothers. The results of this study point to the importance of distinguishing between different groups of workers as well as between different types of arrangements when examining outcomes of flexible working. Furthermore, the results of the study contribute to the argument that performance enhancing flexible working arrangements can potentially exacerbate gender inequalities in the labour market by enabling men to commit more time to their jobs, while for women, especially full-time working mothers, this may be less possible

    Company-level family policies: Who has access to it and what are some of its outcomes

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    Despite the increase in number of studies that examine the cross-national variation in the policy configuration that allow a better work-family integration, very few look beyond the national levels. It is also crucial to examine occupational level welfare since companies may restrict or expand the existing national level regulations, defining the “final availability” workers actual have towards various arrangements. In addition, companies may provide various additional arrangements through occupational policies which are not set out in the national level agreements that are crucial in addressing reconciliation needs of workers. This chapter examines what types of arrangements are provided at the company level to address work-family demands of workers. It further provides a synthesis of studies that examine both national level contexts and individual level characteristics that explain who gets access to company level family-friendly policies, which is linked to the possible outcomes of these policies

    A Study of Cyclic Fatigue, Damage Initiation, Damage Propagation, and Fracture of Welded Titanium Alloy Plate

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    In this paper, the influence of test specimen orientation and microstructure on cyclic stress-amplitude controlled fatigue response, damage initiation, damage propagation and fracture behavior of samples taken from a welded plate of titanium alloy is presented and discussed. Test specimens from the chosen alloy were prepared from an as-welded plate of the material with the stress axis both parallel (longitudinal) and perpendicular (transverse) to the deformed (rolling) direction of the plate. The test specimens were cyclically deformed at different values of maximum stress at a constant load ratio of 0.1, and the resultant cycles-to-failure was recorded. The fracture surfaces of the deformed and failed test specimens were examined in a scanning electron microscope to establish the macroscopic fracture mode, the intrinsic features on the fatigue fracture surface and the role of applied stress-microstructural feature interactions in establishing the microscopic mechanisms governing failure

    A Study of the Tensile Deformation and Fracture Behavior of Commercially Pure Titanium and Titanium Alloy: Influence of Orientation and Microstructure

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    In this paper, the tensile deformation and fracture behavior of commercially pure titanium and the titanium alloy (Ti-6Al-4V) are presented and briefly discussed. Samples of both commercially pure titanium and the Ti-6Al-4V alloy were prepared from the as-provided plate stock along both the longitudinal and transverse orientations. The specimens were then deformed to failure in uniaxial tension. The intrinsic influence of material composition and test specimen orientation on microstructure, tensile properties, and resultant fracture behavior of the two materials is presented. The conjoint influence of intrinsic microstructural features, nature of loading, and specimen orientation on tensile properties of commercially pure titanium and the Ti-6Al-4V alloy is highlighted. The fracture behavior of the two materials is discussed taking into consideration the nature of loading, specimen orientation, and the role and contribution of intrinsic microstructural effects
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