Objective To quantify the dose-response associations between total physical activity and risk of breast cancer, colon cancer, diabetes, ischemic heart disease, and ischemic stroke ...events.Design Systematic review and Bayesian dose-response meta-analysis.Data sources PubMed and Embase from 1980 to 27 February 2016, and references from relevant systematic reviews. Data from the Study on Global AGEing and Adult Health conducted in China, Ghana, India, Mexico, Russia, and South Africa from 2007 to 2010 and the US National Health and Nutrition Examination Surveys from 1999 to 2011 were used to map domain specific physical activity (reported in included studies) to total activity.Eligibility criteria for selecting studies Prospective cohort studies examining the associations between physical activity (any domain) and at least one of the five diseases studied.Results 174 articles were identified: 35 for breast cancer, 19 for colon cancer, 55 for diabetes, 43 for ischemic heart disease, and 26 for ischemic stroke (some articles included multiple outcomes). Although higher levels of total physical activity were significantly associated with lower risk for all outcomes, major gains occurred at lower levels of activity (up to 3000-4000 metabolic equivalent (MET) minutes/week). For example, individuals with a total activity level of 600 MET minutes/week (the minimum recommended level) had a 2% lower risk of diabetes compared with those reporting no physical activity. An increase from 600 to 3600 MET minutes/week reduced the risk by an additional 19%. The same amount of increase yielded much smaller returns at higher levels of activity: an increase of total activity from 9000 to 12 000 MET minutes/week reduced the risk of diabetes by only 0.6%. Compared with insufficiently active individuals (total activity <600 MET minutes/week), the risk reduction for those in the highly active category (≥8000 MET minutes/week) was 14% (relative risk 0.863, 95% uncertainty interval 0.829 to 0.900) for breast cancer; 21% (0.789, 0.735 to 0.850) for colon cancer; 28% (0.722, 0.678 to 0.768) for diabetes; 25% (0.754, 0.704 to 0.809) for ischemic heart disease; and 26% (0.736, 0.659 to 0.811) for ischemic stroke.Conclusions People who achieve total physical activity levels several times higher than the current recommended minimum level have a significant reduction in the risk of the five diseases studied. More studies with detailed quantification of total physical activity will help to find more precise relative risk estimates for different levels of activity.
Tropospheric ozone in CMIP6 simulations Griffiths, Paul T; Murray, Lee T; Zeng, Guang ...
Atmospheric chemistry and physics,
03/2021, Letnik:
21, Številka:
5
Journal Article
Recenzirano
Odprti dostop
The evolution of tropospheric ozone from 1850 to 2100 has been studied using data from Phase 6 of the Coupled Model Intercomparison Project (CMIP6). We evaluate long-term changes using coupled ...atmosphere–ocean chemistry–climate models, focusing on the CMIP Historical and ScenarioMIP ssp370 experiments, for which detailed tropospheric-ozone diagnostics were archived. The model ensemble has been evaluated against a suite of surface, sonde and satellite observations of the past several decades and found to reproduce well the salient spatial, seasonal and decadal variability and trends. The multi-model mean tropospheric-ozone burden increases from 247 ± 36 Tg in 1850 to a mean value of 356 ± 31 Tg for the period 2005–2014, an increase of 44 %. Modelled present-day values agree well with previous determinations (ACCENT: 336 ± 27 Tg; Atmospheric Chemistry and Climate Model Intercomparison Project, ACCMIP: 337 ± 23 Tg; Tropospheric Ozone Assessment Report, TOAR: 340 ± 34 Tg). In the ssp370 experiments, the ozone burden increases to 416 ± 35 Tg by 2100. The ozone budget has been examined over the same period using lumped ozone production (PO3) and loss (LO3) diagnostics. Both ozone production and chemical loss terms increase steadily over the period 1850 to 2100, with net chemical production (PO3-LO3) reaching a maximum around the year 2000. The residual term, which contains contributions from stratosphere–troposphere transport reaches a minimum around the same time before recovering in the 21st century, while dry deposition increases steadily over the period 1850–2100. Differences between the model residual terms are explained in terms of variation in tropopause height and stratospheric ozone burden.
The portable electrochemical generation of hydrogen peroxide (H2O2) from air and water would enable greater utilization of this versatile green oxidant in applications ranging from environmental ...remediation to portable sanitation. Currently, electrochemical H2O2 synthesis is hampered by the lack of low-cost, non-toxic catalysts that selectively reduce O2 to H2O2 and the lack of low-energy methods for separating the produced H2O2 from the electrolyte media. Herein, we show that a disulfonated anthraquinone can simultaneously catalyze the selective conversion of O2 to H2O2 and shuttle between immiscible aqueous and organic phases via ion exchange. We exploit both of these properties in a flow system to assemble an all-Earth-abundant prototype device for the continuous generation and separation of H2O2 into an electrolyte-free water stream. The combination of molecular redox mediation and phase-transfer catalysis demonstrated here has broad implications for the electrochemical synthesis and isolation of value-added chemicals and fuels.
Display omitted
•Phase-transfer catalysis shuttles redox equivalents from the site of electrolysis•Organic electrocatalysis is used to generate H2O2, a high-value liquid product•Hydrogen peroxide is produced in electrolyte-free media, avoiding separation steps•A flow device demonstrates long-term operation at high faradic efficiencies
Hydrogen peroxide (H2O2) is a crucial oxidant for processes as diverse as wood pulping, fine chemical synthesis, water purification, and environmental remediation. Legacy production of peroxide relies on fossil resources and is difficult to downscale. Renewable electricity can be used to drive the electrochemical synthesis of H2O2 directly from H2O and O2, but current electrochemical methods suffer from the use of precious metals, toxic catalyst materials, and the requirement of expensive downstream separation of H2O2 from the electrolyte. We address all of these challenges by coupling electrochemistry with phase-transfer catalysis using organic quinone mediators to furnish continuous H2O2 synthesis and separation.
Negatively charged anthraquinones are reduced electrochemically and can generate hydrogen peroxide (H2O2) by partial oxygen reduction. The use of phase-transfer catalysis allows the production of the product far from the site of electrolysis, facilitating the precious metal-free synthesis of H2O2 in an electrolyte-free medium. A proof-of-concept device is designed to perform this process in continuous flow.
Commercially available carbon blacks serve as effective metal-free catalysts for the selective hydrogenation of carbon–carbon multiple bonds under aerobic conditions using hydrazine as the terminal ...reductant. The reaction, which proceeds through a putative diimide intermediate, displays high tolerance to a variety of functional groups, including those sensitive to nucleophilic displacement by hydrazine, aerobic oxidation, or hydrazine-mediated reduction. Hydrazine chemisorbs strongly to the carbon surface, attenuating its native oxidative reactivity and allowing for selective hydrogenation. The catalytic sequence established here effectively umpolungs the reactivity of carbon, thereby enabling the use of this low-cost material in selective reduction catalysis.
Background
Postoperative complications (POCs) are associated with worse oncologic outcomes in several cancer types. The implications of complications after rectal cancer surgery are not well studied.
...Methods
The United States Rectal Cancer Consortium (2007–2017) was reviewed for primary rectal adenocarcinoma patients who underwent R0/R1 resection. Ninety-day POCs were categorized as major or minor and were grouped into infectious, cardiopulmonary, thromboembolic, renal, or intestinal dysmotility. Primary outcomes were overall survival (OS) and recurrence-free survival (RFS).
Results
Among 1136 patients, the POC rate was 46% (
n
= 527), with 63% classified as minor and 32% classified as major. Of all POCs, infectious complications comprised 20%, cardiopulmonary 3%, thromboembolic 5%, renal 9%, and intestinal dysmotility 19%. Compared with minor or no POCs, major POCs were associated with both worse RFS and worse OS (both
p
< 0.01). Compared with no POCs, a single POC was associated with worse RFS (
p
< 0.01), while multiple POCs were associated with worse OS (
p
= 0.02). Regardless of complication grade, infectious POCs were associated with worse RFS (
p
< 0.01), while cardiopulmonary and thromboembolic POCs were associated with worse OS (both
p
< 0.01). Renal POCs were associated with both worse RFS (
p
< 0.001) and worse OS (
p
= 0.01). After accounting for pathologic stage, neoadjuvant therapy, and final margin status, Multivariable analysis (MVA) demonstrated worse outcomes with cardiopulmonary, thromboembolic, and renal POCs for OS (cardiopulmonary: hazard ratio HR 3.6,
p
= 0.01; thromboembolic: HR 19.4,
p
< 0.01; renal: HR 2.4,
p
= 0.01), and renal and infectious POCs for RFS (infectious: HR 2.1,
p
< 0.01; renal: HR 3.2,
p
< 0.01).
Conclusions
Major complications after proctectomy for cancer are associated with decreased RFS and OS. Given the association of infectious complications and postoperative renal dysfunction with earlier recurrence of disease, efforts must be directed towards defining best practices and standardizing care.
We predict the ionisation potentials of the hole-conducting material SPIRO-OMeTAD and twelve methoxy isomers and polymethoxy derivatives. Based on electronic and economic factors, we identify the ...optimal compounds for application as p-type hole-selective contacts in hybrid halide perovskite solar cells.
The flavoenzyme monoamine oxidase (MAO) regulates mammalian behavioral patterns by modulating neurotransmitters such as adrenaline and serotonin. The mechanistic basis which underpins this enzyme is ...far from agreed upon. Reported herein is that the combination of a synthetic flavin and alloxan generates a catalyst system which facilitates biomimetic amine oxidation. Mechanistic and electron paramagnetic (EPR) spectroscopic data supports the conclusion that the reaction proceeds through a radical manifold. This data provides the first example of a biorelevant synthetic model for monoamine oxidase B activity.
MAO copycat: Mimicry of monoamine oxidase B (MAO B) under aerobic and ambient conditions has been accomplished using a model flavin. Kinetic and EPR studies have offered mechanistic insight, ultimately allowing an appreciation of kinetic similarity to already published data concerning MAO B. A rate‐contributing hydrogen‐atom transfer from the amine substrate to the flavin acceptor is proposed for both the model system and MAO B.
Hybrid halide perovskites are an emerging class of photovoltaic materials, boasting high solar efficiencies from relatively simple preparations. However, the chemical diversity of the A-site organic ...cation is limited, generally due to steric constraints of the (PbI3)− cage. Herein we describe the use of a non-benzenoid Hückel aromatic, (C3H3)+, as a viable alternative to the readily employed methylammonium, formamidinium, and guanidinium A-site cations. (C3H3)+ may lead to greater moisture stability due to the lack of an acidic proton relative to the current (H–NR3)+-based systems while still boasting a narrow electronic band gap (E g = 1.5 eV) and mobile holes and electrons (m h * = −1.27 and m e * = 0.77, respectively).
Cardiac arrhythmias are a major cause of morbidity and mortality worldwide. Although recent advances in cell-based models, including human-induced pluripotent stem cell-derived cardiomyocytes ...(iPSC-CM), are contributing to our understanding of electrophysiology and arrhythmia mechanisms, preclinical animal studies of cardiovascular disease remain a mainstay. Over the past several decades, animal models of cardiovascular disease have advanced our understanding of pathological remodeling, arrhythmia mechanisms, and drug effects and have led to major improvements in pacing and defibrillation therapies. There exist a variety of methodological approaches for the assessment of cardiac electrophysiology and a plethora of parameters may be assessed with each approach. This guidelines article will provide an overview of the strengths and limitations of several common techniques used to assess electrophysiology and arrhythmia mechanisms at the whole animal, whole heart, and tissue level with a focus on small animal models. We also define key electrophysiological parameters that should be assessed, along with their physiological underpinnings, and the best methods with which to assess these parameters.
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