143 research outputs found

    Effect of temperature and reaction time of the synthesis of nanocrystalline brucite

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    Mg(OH)2 nanoparticles has been successfully synthesized by means of the hydrothermal method. The effect of the reaction time and the synthesis temperature on the nanoparticles obtained has also been studied. The physic-chemical properties of the synthesized brucite samples have been characterized by X-Ray-diffraction (XRD), scanning electron microscopy/energy dispersive X-rays analysis (SEM/EDX), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), thermogravimetry/ differential scanning Calorimetry (TG-DSC) and in situ high-temperature X-ray diffraction (XRD). The influence of the synthesis parameters in the brucite samples has been discussed in detail. Furthermore, it has been shown that the increase of temperature from 180 to 200ºC improves the crystallinity degree of Mg(OH)2 nanostructured particles and also, promotes the formation of plates with bigger uniform size. As well, the increase in the time reaction induces the formation of bigger size brucite plates. So, this hydrothermal method has been shown to be a really promising method for the large scale production.Peer Reviewe

    Identifying gaps on health impacts, exposures, and vulnerabilities to climate change on human health and wellbeing in South America: a scoping review

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    There is an important gap in regional information on climate change and health, limiting the development of science-based climate policies in South American countries. This study aims to identify the main gaps in the existing scientific literature on the impacts, exposure, and vulnerabilities of climate change on population health. A scoping review was performed guided by four sub-questions focused on the impacts of climate change on physical and mental health, exposure and vulnerability factors of population to climate hazards. The main findings showed that physical impacts mainly included infectious diseases, while mental health impacts included trauma, depression, and anxiety. Evidence on population exposure to climate hazards is limited, and social determinants of health and individual factors were identified as vulnerability factors. Overall, evidence on the intersection between climate change and health is limited in South America and has been generated in silos, with limited transdisciplinary research. More formal and systematic information should be generated to inform public policy

    Genomic, Pathway Network, and Immunologic Features Distinguishing Squamous Carcinomas

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    This integrated, multiplatform PanCancer Atlas study co-mapped and identified distinguishing molecular features of squamous cell carcinomas (SCCs) from five sites associated with smokin

    Home-Based Respiratory Physiotherapy and Telephone-Based Psychological Support for COVID-19 Survivors in Peru: Protocol for a Randomized Controlled Trial.

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    BACKGROUND: Both pulmonary and mental health are affected following hospitalization for COVID-19 pneumonia. Pulmonary rehabilitation therapy has demonstrated benefits in improving mental health, but no validated combined programs that include mental health have been proposed. OBJECTIVE: This article presents the design of a trial that aimed to assess whether the participation in a combined rehabilitation program that includes home-based respiratory physiotherapy and telephone-based psychological support is associated with a greater improvement of pulmonary and mental health outcomes 7-12 weeks after COVID-19 hospitalization discharge compared with posthospital usual care provided by a public Peruvian hospital. METHODS: WAYRA (the word for air in the Quechua language) was an open-label, unblinded, two-arm randomized controlled trial. We recruited 108 participants aged 18-75 years who were discharged from the hospital after COVID-19 pneumonia that required >6 liters/minute of supplemental oxygen during treatment. Participants were randomly assigned at a 1:1 ratio to receive the combined rehabilitation program or usual posthospital care provided by a public Peruvian hospital. The intervention consisted of 12 at-home respiratory rehabilitation sessions and 6 telephone-based psychological sessions. The primary outcome was the 6-minute walk distance. Secondary outcomes included lung function, mental health status (depression, anxiety, and trauma), and quality of life. Outcomes were assessed at baseline (before randomization) and at 7 and 12 weeks after hospital discharge to assess the difference between arms. RESULTS: This study was funded by the Peruvian National Council of Science Technology and Technology Innovation in July 2020. Ethics approval was obtained on September 2, 2020. Recruitment and data collection occurred between October 2020 and June 2021. Results are expected to be published by the end of 2022. CONCLUSIONS: WAYRA was the first randomized controlled trial evaluating combined pulmonary-mental health rehabilitation for hospitalized COVID-19 survivors in resource-limited settings, potentially providing a foundation for the cost-effective scale-up of similar multidisciplinary rehabilitation programs. TRIAL REGISTRATION: ClinicalTrials.gov NCT04649736; https://clinicaltrials.gov/ct2/show/NCT04649736. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): RR1-10.2196/36001

    Effect of SGLT2 inhibitors on stroke and atrial fibrillation in diabetic kidney disease: Results from the CREDENCE trial and meta-analysis

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    BACKGROUND AND PURPOSE: Chronic kidney disease with reduced estimated glomerular filtration rate or elevated albuminuria increases risk for ischemic and hemorrhagic stroke. This study assessed the effects of sodium glucose cotransporter 2 inhibitors (SGLT2i) on stroke and atrial fibrillation/flutter (AF/AFL) from CREDENCE (Canagliflozin and Renal Events in Diabetes With Established Nephropathy Clinical Evaluation) and a meta-Analysis of large cardiovascular outcome trials (CVOTs) of SGLT2i in type 2 diabetes mellitus. METHODS: CREDENCE randomized 4401 participants with type 2 diabetes mellitus and chronic kidney disease to canagliflozin or placebo. Post hoc, we estimated effects on fatal or nonfatal stroke, stroke subtypes, and intermediate markers of stroke risk including AF/AFL. Stroke and AF/AFL data from 3 other completed large CVOTs and CREDENCE were pooled using random-effects meta-Analysis. RESULTS: In CREDENCE, 142 participants experienced a stroke during follow-up (10.9/1000 patient-years with canagliflozin, 14.2/1000 patient-years with placebo; hazard ratio [HR], 0.77 [95% CI, 0.55-1.08]). Effects by stroke subtypes were: ischemic (HR, 0.88 [95% CI, 0.61-1.28]; n=111), hemorrhagic (HR, 0.50 [95% CI, 0.19-1.32]; n=18), and undetermined (HR, 0.54 [95% CI, 0.20-1.46]; n=17). There was no clear effect on AF/AFL (HR, 0.76 [95% CI, 0.53-1.10]; n=115). The overall effects in the 4 CVOTs combined were: Total stroke (HRpooled, 0.96 [95% CI, 0.82-1.12]), ischemic stroke (HRpooled, 1.01 [95% CI, 0.89-1.14]), hemorrhagic stroke (HRpooled, 0.50 [95% CI, 0.30-0.83]), undetermined stroke (HRpooled, 0.86 [95% CI, 0.49-1.51]), and AF/AFL (HRpooled, 0.81 [95% CI, 0.71-0.93]). There was evidence that SGLT2i effects on total stroke varied by baseline estimated glomerular filtration rate (P=0.01), with protection in the lowest estimated glomerular filtration rate (45 mL/min/1.73 m2]) subgroup (HRpooled, 0.50 [95% CI, 0.31-0.79]). CONCLUSIONS: Although we found no clear effect of SGLT2i on total stroke in CREDENCE or across trials combined, there was some evidence of benefit in preventing hemorrhagic stroke and AF/AFL, as well as total stroke for those with lowest estimated glomerular filtration rate. Future research should focus on confirming these data and exploring potential mechanisms

    Southern African Large Telescope Spectroscopy of BL Lacs for the CTA project

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    In the last two decades, very-high-energy gamma-ray astronomy has reached maturity: over 200 sources have been detected, both Galactic and extragalactic, by ground-based experiments. At present, Active Galactic Nuclei (AGN) make up about 40% of the more than 200 sources detected at very high energies with ground-based telescopes, the majority of which are blazars, i.e. their jets are closely aligned with the line of sight to Earth and three quarters of which are classified as high-frequency peaked BL Lac objects. One challenge to studies of the cosmological evolution of BL Lacs is the difficulty of obtaining redshifts from their nearly featureless, continuum-dominated spectra. It is expected that a significant fraction of the AGN to be detected with the future Cherenkov Telescope Array (CTA) observatory will have no spectroscopic redshifts, compromising the reliability of BL Lac population studies, particularly of their cosmic evolution. We started an effort in 2019 to measure the redshifts of a large fraction of the AGN that are likely to be detected with CTA, using the Southern African Large Telescope (SALT). In this contribution, we present two results from an on-going SALT program focused on the determination of BL Lac object redshifts that will be relevant for the CTA observatory

    Multi-messenger observations of a binary neutron star merger

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    On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

    Global patient outcomes after elective surgery: prospective cohort study in 27 low-, middle- and high-income countries.

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    BACKGROUND: As global initiatives increase patient access to surgical treatments, there remains a need to understand the adverse effects of surgery and define appropriate levels of perioperative care. METHODS: We designed a prospective international 7-day cohort study of outcomes following elective adult inpatient surgery in 27 countries. The primary outcome was in-hospital complications. Secondary outcomes were death following a complication (failure to rescue) and death in hospital. Process measures were admission to critical care immediately after surgery or to treat a complication and duration of hospital stay. A single definition of critical care was used for all countries. RESULTS: A total of 474 hospitals in 19 high-, 7 middle- and 1 low-income country were included in the primary analysis. Data included 44 814 patients with a median hospital stay of 4 (range 2-7) days. A total of 7508 patients (16.8%) developed one or more postoperative complication and 207 died (0.5%). The overall mortality among patients who developed complications was 2.8%. Mortality following complications ranged from 2.4% for pulmonary embolism to 43.9% for cardiac arrest. A total of 4360 (9.7%) patients were admitted to a critical care unit as routine immediately after surgery, of whom 2198 (50.4%) developed a complication, with 105 (2.4%) deaths. A total of 1233 patients (16.4%) were admitted to a critical care unit to treat complications, with 119 (9.7%) deaths. Despite lower baseline risk, outcomes were similar in low- and middle-income compared with high-income countries. CONCLUSIONS: Poor patient outcomes are common after inpatient surgery. Global initiatives to increase access to surgical treatments should also address the need for safe perioperative care. STUDY REGISTRATION: ISRCTN5181700

    The 2022 South America report of The Lancet Countdown on health and climate change: trust the science. Now that we know, we must act

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    The health of South American populations is being severely impacted by increasing climate change-driven environmental changes. Exacerbated by increased social inequities and vulnerability, deforestation, land degradation, and global climate variabilities in sea temperature, can potentially lead to extreme weather and climate events, magnifying the negative effects of climate change on health. Understanding the direct and indirect exposure routes to climate hazards and the effects on health and wellbeing is critical to design successful and effective evidence-based adaptation and mitigation plans and policies. This report is part of the Lancet Countdown's broader efforts to develop expertise and understanding of the links between health and climate change at the regional level. The Lancet Countdown South America (LCSA), a newly launched chapter of the Lancet Countdown, is an independent, multidisciplinary academic collaboration dedicated to tracking the links between public health and climate change in South America (SA). This collaboration brings together 21 academic institutions and UN agencies with 28 researchers representing various disciplines. The data and results provided in this report for the 12 countries of the region,∗ explore in regional detail the results of the 2022 global Lancet Countdown report and provide the evidence to support targeted response strategies for decision-makers. Its findings and conclusions represent the consensus of experts across multiple fields, covering 25 indicators summarised below in four key messages
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