Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.402
Filtrar
Más filtros

Tipo del documento
Intervalo de año de publicación
1.
Phys Rev Lett ; 132(24): 241802, 2024 Jun 14.
Artículo en Inglés | MEDLINE | ID: mdl-38949350

RESUMEN

A search is presented for baryon number violating interactions in top quark production and decay. The analysis uses data from proton-proton collisions at a center-of-mass energy of 13 TeV, collected with the CMS detector at the LHC with an integrated luminosity of 138 fb^{-1}. Candidate events are selected by requiring two oppositely charged leptons (electrons or muons) and exactly one jet identified as originating from a bottom quark. Multivariate discriminants are used to separate the signal from the background. No significant deviation from the standard model prediction is observed. Upper limits are placed on the strength of baryon number violating couplings. For the first time the production of single top quarks via baryon number violating interactions is studied. This allows the search to set the most stringent constraints to date on the branching fraction of the top quark decay to a lepton, an up-type quark (u or c), and a down-type quark (d, s, or b). The results improve the previous bounds by 3 to 6 orders of magnitude based on the fermion flavor combination of the baryon number violating interactions.

2.
Phys Rev Lett ; 133(7): 071903, 2024 Aug 16.
Artículo en Inglés | MEDLINE | ID: mdl-39213583

RESUMEN

Energy correlators that describe energy-weighted distances between two or three particles in a hadronic jet are measured using an event sample of sqrt[s]=13 TeV proton-proton collisions collected by the CMS experiment and corresponding to an integrated luminosity of 36.3 fb^{-1}. The measured distributions are consistent with the trends in the simulation that reveal two key features of the strong interaction: confinement and asymptotic freedom. By comparing the ratio of the measured three- and two-particle energy correlator distributions with theoretical calculations that resum collinear emissions at approximate next-to-next-to-leading-logarithmic accuracy matched to a next-to-leading-order calculation, the strong coupling is determined at the Z boson mass: α_{S}(m_{Z})=0.1229_{-0.0050}^{+0.0040}, the most precise α_{S}(m_{Z}) value obtained using jet substructure observables.

3.
Phys Rev Lett ; 133(5): 052301, 2024 Aug 02.
Artículo en Inglés | MEDLINE | ID: mdl-39159117

RESUMEN

We report a measurement of exclusive J/ψ and ψ(2s) photoproduction in Au+Au ultraperipheral collisions at sqrt[s_{NN}]=200 GeV using the STAR detector. For the first time, (i) the ψ(2s) photoproduction in midrapidity at the Relativistic Heavy-Ion Collider has been experimentally measured; (ii) nuclear suppression factors are measured for both the coherent and incoherent J/ψ production. At average photon-nucleon center-of-mass energy of 25.0 GeV, the coherent and incoherent J/ψ cross sections of Au nuclei are found to be 71±10% and 36±7%, respectively, of that of free protons. The stronger suppression observed in the incoherent production provides a new experimental handle to study the initial-state parton density in heavy nuclei. Data are compared with theoretical models quantitatively.

4.
Public Health ; 236: 153-160, 2024 Aug 28.
Artículo en Inglés | MEDLINE | ID: mdl-39208709

RESUMEN

OBJECTIVES: Tobacco use is one of the greatest public health problems in the world. Prevalence of alcohol and tobacco use among lactating women ranged between 35.9-83.0% and 1.4-6.1%, respectively, in various parts of the world. Both alcohol and nicotine pass quickly into breast milk. The objective of this study is to estimate the prevalence of alcohol and tobacco use in lactating women and its association with having underweight, stunted, and wasted nursing children in India. The study also draws comparisons to identify the common associated socio-economic factors for alcohol and tobacco use among lactating women and having underweight, stunted, and/or wasted children. STUDY DESIGN: A cross-sectional analytical study involving secondary data from the National Family Health Survey-5. METHODS: A cross-sectional analytical study involving secondary data from the National Family Health Survey-5 conducted nationally in community settings in two phases during 2019-2021. Alcohol and tobacco use among lactating women was self-reported, and the nutritional status of children was assess anthropometrically during the survey and categorised into under-weight, stunted, and wasted as per standardised growth charts. RESULTS: prevalence of tobacco use among currently lactating mothers in India was 3.24%. Prevalence of alcohol use among currently lactating mothers was 0.57%. Nursing children of mothers consuming alcohol had significantly higher odds of being wasted [OR = 1.44; (95% CI = 1.07-1.92)]. Richer wealth index {compared to poor, poorer [OR = 0.74; (95% CI = 0.59-0.91)], rich [OR = 0.64; (95% CI = 0.50-0.84)], richer [OR = 0.46; (95% CI = 0.33-0.65)], richest [OR = 0.19; (95% CI = 0.11-0.33)]}, higher education status {compared to illiterate, secondary education [OR = 0.79; (95% CI = 0.63-0.97)], higher education [OR = 0.38; (95% CI = 0.24-0.62)]}, and non-tribal ethnicity [OR = 0.40; (95% CI = 0.33-0.50)] were found to be significantly associated with lower odds of alcohol and tobacco use among lactating mothers. Age, religion, residence, and occupation were also found to be significantly associated. CONCLUSIONS: Lactating women with lower education status or belonging to lower income groups needs to be prioritised for further qualitative assessment of alcohol and tobacco use during lactation. Our study reflects the national and state-level prevalence of alcohol and tobacco use among lactating women, which often masks the local and community-level intricacies. There is a need to further explore local and community-level factors affecting alcohol use during lactation and its association with child nutrition.

5.
Environ Manage ; 74(5): 870-885, 2024 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-39210029

RESUMEN

Anthropogenic and climatic changes are continuously altering the freshwater plankton, necessitating an evaluation of the complex structure of plankton communities to understand and mitigate these impacts. In this context, the present study focuses on evaluating the structure of plankton communities, specifically Phytoplankton Functional Groups (FGs) for assessing the environmental sensitivity of wetlands under changing scenario. These FGs are defined by shared adaptive features rather than taxonomic traits. Over the period from 2016 to 2018, two ecologically distinct wetlands were examined, analysing their phytoplankton FGs and their relationship with water quality parameters. Ecohydrological data revealed significant seasonal variations (p ≤ 0.05) in key parameters such as water depth, temperature, pH, electrical conductivity, dissolved oxygen, total alkalinity, total hardness, NO3-N, and PO4-P. Notably, there were no significant differences observed among the sampling stations within each wetland. A total of 125 phytoplankton genera/species were classified into 23 FGs in the open wetland and 22 FGs in the closed wetland. Spatial and seasonal analyses of dominant FGs suggested both wetlands were experiencing pollution pressures. This study highlights the powerful role of phytoplankton functional groups (FGs) as bioindicators of wetland health, uncovering pollution pressures. In open wetlands, 15 phytoplankton FGs with 36 key taxa (Indicator Value ≥ 40%) emerged as critical indicators, while in closed wetlands, only 10 FGs with 17 taxa were identified. To assess eutrophication, the occurrence of these indicator species was evaluated using BVSTEP function analysis. The study recommends pollution reduction in catchment areas and restoration of riverine connectivity to enhance FG diversity. Phytoplankton FG methodologies are deemed effective for assessing the environmental sensitivity of wetlands significantly impacted by human activities. This research offers a scientific foundation for the evaluation and restoration of wetland ecosystems.


Asunto(s)
Fitoplancton , Humedales , Monitoreo del Ambiente/métodos , Calidad del Agua , Estaciones del Año
6.
Niger J Clin Pract ; 27(4): 534-536, 2024 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-38679778

RESUMEN

ABSTRACT: A femoral hernia is an uncommon and acquired hernia in the groin. Its incidence in adults is 2%-8% of all abdominal wall hernias, and it has a female-to-male ratio of 1.8:1. It is usually found in elderly patients and is associated with increased morbidity due to delays in diagnosis leading to a high incidence of incarceration and strangulation. Accurate preoperative diagnosis of femoral hernia is challenging, especially in obese patients in whom a small femoral hernia can be hidden under the groin fat. Unlike an inguinal hernia, it rarely reduces on its own and if asymptomatic and small, is often unnoticed by the elderly obese patient. Femoral hernia is often unsuspected and overlooked in males as it is predominant among females. Delay in diagnosis can lead to intestinal gangrene and high morbidity. We present a case of an incarcerated left femoral hernia in an elderly obese male who presented with acute intestinal obstruction. He was managed with resection of the gangrenous segment and double barrel ileostomy. Although uncommon in males, a femoral hernia has a high incidence of strangulation, and therefore should always be ruled out as a cause of acute intestinal obstruction in elderly patients. Therefore, never forget to examine the groin in case of intestinal obstruction.


Asunto(s)
Hernia Femoral , Obstrucción Intestinal , Humanos , Hernia Femoral/cirugía , Hernia Femoral/diagnóstico , Hernia Femoral/complicaciones , Masculino , Obstrucción Intestinal/etiología , Obstrucción Intestinal/diagnóstico , Obstrucción Intestinal/cirugía , Anciano , Tomografía Computarizada por Rayos X , Obesidad/complicaciones , Gangrena/diagnóstico , Gangrena/cirugía , Diagnóstico Diferencial
7.
Phys Rev Lett ; 131(20): 202301, 2023 Nov 17.
Artículo en Inglés | MEDLINE | ID: mdl-38039468

RESUMEN

The polarization of Λ and Λ[over ¯] hyperons along the beam direction has been measured relative to the second and third harmonic event planes in isobar Ru+Ru and Zr+Zr collisions at sqrt[s_{NN}]=200 GeV. This is the first experimental evidence of the hyperon polarization by the triangular flow originating from the initial density fluctuations. The amplitudes of the sine modulation for the second and third harmonic results are comparable in magnitude, increase from central to peripheral collisions, and show a mild p_{T} dependence. The azimuthal angle dependence of the polarization follows the vorticity pattern expected due to elliptic and triangular anisotropic flow, and qualitatively disagrees with most hydrodynamic model calculations based on thermal vorticity and shear induced contributions. The model results based on one of existing implementations of the shear contribution lead to a correct azimuthal angle dependence, but predict centrality and p_{T} dependence that still disagree with experimental measurements. Thus, our results provide stringent constraints on the thermal vorticity and shear-induced contributions to hyperon polarization. Comparison to previous measurements at RHIC and the LHC for the second-order harmonic results shows little dependence on the collision system size and collision energy.

8.
Phys Rev Lett ; 130(21): 212301, 2023 May 26.
Artículo en Inglés | MEDLINE | ID: mdl-37295104

RESUMEN

We report here the first observation of directed flow (v_{1}) of the hypernuclei _{Λ}^{3}H and _{Λ}^{4}H in mid-central Au+Au collisions at sqrt[s_{NN}]=3 GeV at RHIC. These data are taken as part of the beam energy scan program carried out by the STAR experiment. From 165×10^{6} events in 5%-40% centrality, about 8400 _{Λ}^{3}H and 5200 _{Λ}^{4}H candidates are reconstructed through two- and three-body decay channels. We observe that these hypernuclei exhibit significant directed flow. Comparing to that of light nuclei, it is found that the midrapidity v_{1} slopes of _{Λ}^{3}H and _{Λ}^{4}H follow baryon number scaling, implying that the coalescence is the dominant mechanism for these hypernuclei production in the 3 GeV Au+Au collisions.

9.
Phys Rev Lett ; 130(20): 202301, 2023 May 19.
Artículo en Inglés | MEDLINE | ID: mdl-37267557

RESUMEN

We report the triton (t) production in midrapidity (|y|<0.5) Au+Au collisions at sqrt[s_{NN}]=7.7-200 GeV measured by the STAR experiment from the first phase of the beam energy scan at the Relativistic Heavy Ion Collider. The nuclear compound yield ratio (N_{t}×N_{p}/N_{d}^{2}), which is predicted to be sensitive to the fluctuation of local neutron density, is observed to decrease monotonically with increasing charged-particle multiplicity (dN_{ch}/dη) and follows a scaling behavior. The dN_{ch}/dη dependence of the yield ratio is compared to calculations from coalescence and thermal models. Enhancements in the yield ratios relative to the coalescence baseline are observed in the 0%-10% most central collisions at 19.6 and 27 GeV, with a significance of 2.3σ and 3.4σ, respectively, giving a combined significance of 4.1σ. The enhancements are not observed in peripheral collisions or model calculations without critical fluctuation, and decreases with a smaller p_{T} acceptance. The physics implications of these results on the QCD phase structure and the production mechanism of light nuclei in heavy-ion collisions are discussed.

10.
Phys Rev Lett ; 130(24): 242301, 2023 Jun 16.
Artículo en Inglés | MEDLINE | ID: mdl-37390421

RESUMEN

The elliptic (v_{2}) and triangular (v_{3}) azimuthal anisotropy coefficients in central ^{3}He+Au, d+Au, and p+Au collisions at sqrt[s_{NN}]=200 GeV are measured as a function of transverse momentum (p_{T}) at midrapidity (|η|<0.9), via the azimuthal angular correlation between two particles both at |η|<0.9. While the v_{2}(p_{T}) values depend on the colliding systems, the v_{3}(p_{T}) values are system independent within the uncertainties, suggesting an influence on eccentricity from subnucleonic fluctuations in these small-sized systems. These results also provide stringent constraints for the hydrodynamic modeling of these systems.


Asunto(s)
Hidrodinámica , Masculino , Humanos , Anisotropía , Movimiento (Física)
11.
Phys Rev Lett ; 130(8): 082301, 2023 Feb 24.
Artículo en Inglés | MEDLINE | ID: mdl-36898098

RESUMEN

We report the beam energy and collision centrality dependence of fifth and sixth order cumulants (C_{5}, C_{6}) and factorial cumulants (κ_{5}, κ_{6}) of net-proton and proton number distributions, from center-of-mass energy (sqrt[s_{NN}]) 3 GeV to 200 GeV Au+Au collisions at RHIC. Cumulant ratios of net-proton (taken as proxy for net-baryon) distributions generally follow the hierarchy expected from QCD thermodynamics, except for the case of collisions at 3 GeV. The measured values of C_{6}/C_{2} for 0%-40% centrality collisions show progressively negative trend with decreasing energy, while it is positive for the lowest energy studied. These observed negative signs are consistent with QCD calculations (for baryon chemical potential, µ_{B}≤110 MeV) which contains the crossover transition range. In addition, for energies above 7.7 GeV, the measured proton κ_{n}, within uncertainties, does not support the two-component (Poisson+binomial) shape of proton number distributions that would be expected from a first-order phase transition. Taken in combination, the hyperorder proton number fluctuations suggest that the structure of QCD matter at high baryon density, µ_{B}∼750 MeV at sqrt[s_{NN}]=3 GeV is starkly different from those at vanishing µ_{B}∼24 MeV at sqrt[s_{NN}]=200 GeV and higher collision energies.

12.
Phys Rev Lett ; 130(11): 112301, 2023 Mar 17.
Artículo en Inglés | MEDLINE | ID: mdl-37001106

RESUMEN

We report on measurements of sequential ϒ suppression in Au+Au collisions at sqrt[s_{NN}]=200 GeV with the STAR detector at the Relativistic Heavy Ion Collider (RHIC) through both the dielectron and dimuon decay channels. In the 0%-60% centrality class, the nuclear modification factors (R_{AA}), which quantify the level of yield suppression in heavy-ion collisions compared to p+p collisions, for ϒ(1S) and ϒ(2S) are 0.40±0.03(stat)±0.03(sys)±0.09(norm) and 0.26±0.08(stat)±0.02(sys)±0.06(norm), respectively, while the upper limit of the ϒ(3S) R_{AA} is 0.17 at a 95% confidence level. This provides experimental evidence that the ϒ(3S) is significantly more suppressed than the ϒ(1S) at RHIC. The level of suppression for ϒ(1S) is comparable to that observed at the much higher collision energy at the Large Hadron Collider. These results point to the creation of a medium at RHIC whose temperature is sufficiently high to strongly suppress excited ϒ states.

13.
Anim Biotechnol ; 34(1): 25-38, 2023 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-34106815

RESUMEN

In addition to the transmission of paternal genome, spermatozoa also carry coding as well as noncoding microRNAs (miRNAs) into the female oocyte during the process of biological fertilization. Based on RNA deep sequencing, a total 28 number of differentially expressed miRNAs were cataloged in categorized FrieswalTM crossbred (Holstein Friesian X Sahiwal) bull semen on the basis of conception rate (CR) in field progeny testing program. Validation of selected miRNAs viz. bta-mir-182, bta-let-7b, bta-mir-34c and bta-mir-20a revealed that, superior bull semen having comparatively (p < .05) lower level of all the miRNAs in contrast to inferior bull semen. Additionally, it was illustrated that, bta-mir-20a and bta-mir-34c miRNAs are negatively (p < .01) correlated with seminal plasma catalase (CAT) activity and glutathione peroxidase (GPx) level. Interactome studies identified that bta-mir-140, bta-mir-342, bta-mir-1306 and bta-mir-217 can target few of the important solute carrier (SLC) proteins viz. SLC30A3, SLC39A9, SLC31A1 and SLC38A2, respectively. Interestingly, it was noticed that all the SLCs were significantly (p < .05) expressed at higher level in superior quality bull semen and they are negatively correlated (p < .01) with their corresponding miRNAs as mentioned. This study may reflect the role of miRNAs in regulating few of the candidate genes and thus may influence the bull semen quality traits.


Asunto(s)
MicroARNs , Semen , Bovinos , Animales , Masculino , Femenino , MicroARNs/genética , Análisis de Semen , Espermatozoides/metabolismo , Hibridación Genética
14.
Tech Coloproctol ; 28(1): 10, 2023 12 13.
Artículo en Inglés | MEDLINE | ID: mdl-38091118

RESUMEN

BACKGROUND: A common and debilitating complication of low anterior resection for rectal cancer is low anterior resection syndrome (LARS). As a multifactorial entity, LARS is poorly understood and challenging to treat. Despite this, prevention strategies are commonly overlooked. Our aim was to review the pathophysiology of LARS and explore current evidence on the efficacy and feasibility of prophylactic techniques. METHODS: A literature review was performed between [1st January 2000 to 1st October 2023] for studies which investigated preventative interventions for LARS. Mechanisms by which LARS develop are described, followed by a review of prophylactic strategies to prevent LARS. Medline, Cochrane, and PubMed databases were searched, 189 articles screened, 8 duplicates removed and 18 studies reviewed. RESULTS: Colonic dysmotility, anal sphincter dysfunction and neorectal dysfunction all contribute to the development of LARS, with the complex mechanism of defecation interrupted by surgery. Transanal irrigation (TAI) and pelvic floor rehabilitation (PFR) have shown benefits in preventing LARS, but may be limited by patient compliance. Intraoperative nerve monitoring (IONM) and robotic-assisted surgery have shown some promise in surgically preventing LARS. Nerve stimulation and other novel strategies currently used in treatment of LARS have yet to be investigated in their roles prophylactically. CONCLUSIONS: To date, there is a limited evidence base for all preventative strategies including IONM, RAS, PFP and TAI. These strategies are limited by either access (IONM, RAS and PFP) or acceptability (PFP and TAI), which are both key to the success of any intervention. The results of ongoing trials will serve to assess acceptability, while technological advancement may improve access to some of the aforementioned strategies.


Asunto(s)
Neoplasias del Recto , Procedimientos Quirúrgicos Robotizados , Humanos , Canal Anal/cirugía , Síndrome de Resección Anterior Baja , Complicaciones Posoperatorias/etiología , Complicaciones Posoperatorias/prevención & control , Calidad de Vida , Neoplasias del Recto/cirugía , Neoplasias del Recto/complicaciones , Procedimientos Quirúrgicos Robotizados/efectos adversos
15.
Orbit ; 42(3): 256-261, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-35801669

RESUMEN

PURPOSE: To identify the risk factors associated with the development of ocular surface exposure and severe visual impairment (SVI) in patients with facial nerve palsy (FNP). METHODS: Ocular data of all consecutive FNP patients (N = 1870) presenting to an eye-care network over the past 10 years were reviewed. Risk factors associated with SVI (best-corrected visual acuity <20/200) and ocular surface exposure at presentation were evaluated using multivariate analysis and odds ratios (OR). RESULTS: The prevalence of SVI was 15%, and 47% had ocular surface exposure at the first presentation. The presence of corneal scar (28% vs. 10.2%, p < .001; OR 3.05), corneal ulcer (12.9% vs. 2.3%, p < .001; OR 4.67), older age at presentation (p < .001; OR 1.02), >10 mm lagophthalmos (p < .001; OR 8.7), male sex, and duration of FNP (p = .021; OR 1) were independent risk factors for developing SVI. Of the 893 eyes with ocular surface exposure, 75 (3.9%) had a corneal ulcer, and 11 (0.6%) were perforated, with the rest having epithelial defects and punctate keratopathy. Patients with neoplastic etiology (15.9% vs. 5.7%; p < .001; OR 2.39), lagophthalmos (49% vs. 29.7%; p < .001; OR 2.25) and poor Bell's phenomenon (9.4% vs. 4.2%; p = .005; OR 1.8) had twofold risk for developing ocular surface exposure. CONCLUSION: Eyes with lagophthalmos, poor Bell's phenomenon, and FNP of neoplastic etiology have a higher risk of developing ocular surface exposure. Male sex, increasing age, longer duration of FNP, and >10 mm lagophthalmos are associated with SVI in FNP patients; hence, early and timely intervention is necessary.


Asunto(s)
Parálisis de Bell , Úlcera de la Córnea , Parálisis Facial , Lagoftalmos , Humanos , Masculino , Niño , Nervio Facial , Parálisis Facial/epidemiología , Parálisis de Bell/complicaciones , Trastornos de la Visión , Factores de Riesgo
16.
Bull Environ Contam Toxicol ; 111(3): 44, 2023 Sep 16.
Artículo en Inglés | MEDLINE | ID: mdl-37715801

RESUMEN

Moyna of Purba Medinipur district is widely known as an aquaculture hub of West Bengal, India. Though very good production is achievable from this fish culture system, management practices are inappropriate, which could create the sustainability problem of this culture system. The present study was thus undertaken for the estimation of plankton population, water quality, carbon footprint and carbon sequestration of this intensive aquaculture practices. Information on spawn to fry, fry to fingerlings and grow-out culture were collected through the structured questionnaire from the fish farmers. The plankton density, primary productivity, carbon footprint and carbon sequestration were analyzed using standard procedures. The phytoplankton, zooplankton and primary productivity were maximum at the stocking period and minimum during the middle of culture period. The lowest feed conversion ratio (FCR) was noticed with the minimum amount of feed applied in the pond. The CO2-e emission ranged from 0.56 to 4.89 kg CO2-e/kg fish (av. 2.13) for the production levels of 5.0 to 10.7 t/ha/yr. The pond water developed salinity and ammonium-N increased from 0.01 to 0.50 mg/l. The ponds with high feed loading (28 to 32 t/ha/yr) had the highest average sediment accumulation rate (11.0 ± 3.0 cm/yr) and carbon sequestration (704 ± 30 g C/m2/yr).


Asunto(s)
Huella de Carbono , Secuestro de Carbono , Animales , Dióxido de Carbono , Acuicultura , India , Plancton
17.
Sci Sports ; 2023 Jun 28.
Artículo en Inglés | MEDLINE | ID: mdl-38620146

RESUMEN

Objectives: The objectives of this scoping review are to discuss, firstly, the positive aspects of wearing face masks during training (such as a barrier to COVID-19 transmission, air pollutant exposure, and adding load on respiratory resistance flow); secondly, the negative aspects (adverse effects on body temperature and hypoxia risks); and thirdly, the training responses of wearing face masks on aerobic and anaerobic performance. News: Besides social distancing and hand hygiene, wearing a face mask is proposed to be the prime advocacy for virus containment. During the period of high risk of contamination, the return to sport guidelines proposed by international and national sport federations included wearing face masks during training sessions. However, it is necessary to discuss the pros and cons of wearing face masks during exercise. Prospects: Although it was essential to wear a face mask during exercise or sport-specific training, there is conflicting evidence on the implications of the use of face masks on physical, physiological as well as psychological well-being or performance. Based on the conflicting empirical findings and anecdotal evidence, certain recommendations have been made for adequate use of face masks during exercise; both to break the chain of transmission and prevent the physiological compromise expected from wearing face masks during exercise. The present review can help stakeholders balance sport guidelines in the event of a respiratory virus pandemic with athlete safety. Conclusion: Conflicting evidence of mechanistic links between the dose of exercise and the possible adverse effects associated with exercising with face masks is available. Adequately powered studies with strong methodological quality on appropriate selection of masks and usage based on the intensity, duration, and type of sport, age, and gender is needed now for the stakeholders to make informed decisions with respect to exercising with face masks.


Objectifs: Les objectifs de cette revue des connaissances sont de discuter, premièrement, les aspects positifs du port de masques pendant l'entraînement (comme une barrière à la transmission du COVID-19, l'exposition aux polluants atmosphériques et l'ajout de charge sur le flux de résistance respiratoire) ; deuxièmement, les aspects négatifs (effets indésirables sur la température corporelle et risques d'hypoxie) ; et troisièmement, les conséquences du port de masques faciaux à l'entraînement sur les performances aérobie et anaérobie. Nouvelles connaissances: Outre la distanciation physique et l'hygiène des mains, le port d'un masque facial est proposé comme le principal plaidoyer pour la maîtrise des contaminations par le nouveau coronavirus. Pendant la période à haut risque de contamination, les directives de retour au sport proposées par les fédérations sportives internationales et nationales incluaient le port de masques lors des séances d'entraînement. Cependant, il est nécessaire de discuter les avantages et les inconvénients du port de masques faciaux pendant l'exercice. Perspectives: Bien qu'il fut essentiel de porter un masque facial pendant l'exercice ou l'entraînement spécifique au sport, il existe des preuves contradictoires sur les implications des masques faciaux sur les performances physiques, physiologiques, et le bien-être psychologique. Sur la base des résultats contradictoires et de données empiriques, certaines recommandations ont été faites pour une utilisation optimale de masques faciaux pendant l'exercice, à la fois pour briser la chaîne de transmission du virus et éviter le compromis physiologique attendu du port des masques faciaux pendant l'exercice. La présente revue peut aider les parties prenantes à trouver un équilibre entre les directives sportives en cas de pandémie par un virus respiratoire et la sécurité des athlètes. Conclusion: Il existe des données contradictoires sur les liens mécanistiques entre la dose d'exercice et les effets indésirables possibles associés à l'exercice avec des masques faciaux. Des études de qualité au plan méthodologique, sur la sélection des masques, leur utilisation en fonction de l'intensité, de la durée et du type de sport, de l'âge et du sexe des sportifs sont nécessaires pour que les parties prenantes puissent prendre des décisions éclairées en ce qui concerne l'exercice avec des masques faciaux.

18.
Soft Matter ; 18(5): 1005-1012, 2022 Feb 02.
Artículo en Inglés | MEDLINE | ID: mdl-35018946

RESUMEN

High density functional polymer nanocomposites (PNCs) with high degree of dispersion have recently emerged as novel materials for various thermo-mechanical, optical and electrical applications. The key challenge is to attain a high loading while maintaining reasonable dispersion to attain maximum possible benefits from the functional nanoparticle additives. Here, we report a facile method to prepare polymer grafted nanoparticle (PGNP)-based high density functional polymer nanocomposites using thermal activation of a high density PGNP monolayer to overcome entropic or enthalpic barriers to insertion of PGNPs into the underlying polymer films. We monitor the temperature-dependent kinetics of penetration of a high density PGNP layer and correlate the penetration time to the effective enthalpic/entropic barriers. The experimental results are corroborated by coarse-grained molecular dynamics simulations. Repeated application of the methodology to insert nanoparticles by appropriate control over temperature, time and graft-chain properties can lead to enhanced densities of loading in the PNC. Our method can be engineered to produce a wide range of high density polymer nanocomposite membranes for various possible applications including gas separation and water desalination.

19.
J Cardiovasc Magn Reson ; 24(1): 66, 2022 11 24.
Artículo en Inglés | MEDLINE | ID: mdl-36419059

RESUMEN

BACKGROUND: Cardiac diffusion tensor imaging (cDTI) using cardiovascular magnetic resonance (CMR) is a novel technique for the non-invasive assessment of myocardial microstructure. Previous studies have shown myocardial infarction to result in loss of sheetlet angularity, derived by reduced secondary eigenvector (E2A) and reduction in subendocardial cardiomyocytes, evidenced by loss of myocytes with right-handed orientation (RHM) on helix angle (HA) maps. Myocardial strain assessed using feature tracking-CMR (FT-CMR) is a sensitive marker of sub-clinical myocardial dysfunction. We sought to explore the relationship between these two techniques (strain and cDTI) in patients at 3 months following ST-elevation MI (STEMI). METHODS: 32 patients (F = 28, 60 ± 10 years) underwent 3T CMR three months after STEMI (mean interval 105 ± 17 days) with second order motion compensated (M2), free-breathing spin echo cDTI, cine gradient echo and late gadolinium enhancement (LGE) imaging. HA maps divided into left-handed HA (LHM, - 90 < HA < - 30), circumferential HA (CM, - 30° < HA < 30°), and right-handed HA (RHM, 30° < HA < 90°) were reported as relative proportions. Global and segmental analysis was undertaken. RESULTS: Mean left ventricular ejection fraction (LVEF) was 44 ± 10% with a mean infarct size of 18 ± 12 g and a mean infarct segment LGE enhancement of 66 ± 21%. Mean global radial strain was 19 ± 6, mean global circumferential strain was - 13 ± - 3 and mean global longitudinal strain was - 10 ± - 3. Global and segmental radial strain correlated significantly with E2A in infarcted segments (p = 0.002, p = 0.011). Both global and segmental longitudinal strain correlated with RHM of infarcted segments on HA maps (p < 0.001, p = 0.003). Mean Diffusivity (MD) correlated significantly with the global infarct size (p < 0.008). When patients were categorised according to LVEF (reduced, mid-range and preserved), all cDTI parameters differed significantly between the three groups. CONCLUSION: Change in sheetlet orientation assessed using E2A from cDTI correlates with impaired radial strain. Segments with fewer subendocardial cardiomyocytes, evidenced by a lower proportion of myocytes with right-handed orientation on HA maps, show impaired longitudinal strain. Infarct segment enhancement correlates significantly with E2A and RHM. Our data has demonstrated a link between myocardial microstructure and contractility following myocardial infarction, suggesting a potential role for CMR cDTI to clinically relevant functional impact.


Asunto(s)
Infarto del Miocardio , Infarto del Miocardio con Elevación del ST , Humanos , Imagen de Difusión Tensora , Volumen Sistólico , Medios de Contraste , Infarto del Miocardio con Elevación del ST/diagnóstico por imagen , Gadolinio , Función Ventricular Izquierda , Valor Predictivo de las Pruebas , Miocardio , Infarto del Miocardio/diagnóstico por imagen , Miocitos Cardíacos , Espectroscopía de Resonancia Magnética
20.
Phys Chem Chem Phys ; 24(46): 28271-28282, 2022 Nov 30.
Artículo en Inglés | MEDLINE | ID: mdl-36382658

RESUMEN

Manganese tungstate (MnWO4) has been widely studied over the past few years due to its outstanding magnetic, catalytic, and sensing features. However, the electrochemical properties of the morphology tuned MnWO4 nanoform is less explored in the literature. Herein, we report the synthesis of MnWO4 nanostructures of different aspect ratios by subtle tuning of the reaction temperature and reaction time. An immediate utility of the size-controlled nanostructures is their use as the electrode material for supercapacitors. The impact of various reaction parameters, namely the growth time and processing temperature, over the MnWO4 nanorods size was studied by different characterization techniques, such as X-ray diffraction, field emission scanning electron microscopy, and Raman spectroscopy. It was shown that all the samples showed considerably good charge-storage properties with the highest values of specific capacitance being 455.07 and 239.07 F g-1 at 2 mV s-1 and 1 A g-1, respectively. The corresponding sample further showed an appreciable capacitance retention of ∼94% even after 10 000 long charge-discharge cycles, indicating a high electrochemical stability of the electrode. Theoretical analysis using density functional theory predicted that the presence of electronic states near Fermi level and the enhanced quantum capacitance were the prime reasons behind the excellent charge-storage performance of the as-synthesized MnWO4.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA