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1.
ACS Sustain Chem Eng ; 12(11): 4718-4730, 2024 Mar 18.
Artículo en Inglés | MEDLINE | ID: mdl-38516397

RESUMEN

Modern technologies transform biomass into commodity chemicals, biofuels, and solid charcoal, making it appear as a renewable resource rather than organic waste. The effectiveness of Mo, Fe, Co, and Ni metal catalysts was investigated during the gasification of lignocellulosic pinewood. The primary goal was to compare the performance of iron and nickel catalysts in the low- and high-pressure production of syngas from pinewood. This is the first study that has reported high-pressure gasification of pinewood without the use of an external gasifying agent, producing syngas containing hydrogen, carbon monoxide, and carbon dioxide along with considerable amounts of methane with or without a catalyst. Also, the same gasification at low pressures was compared. In this study, the iron catalyst produces syngas more efficiently at higher pressure and 800 °C, and contains 43 mol % H2, 22 mol % CO2, 26 mol % CH4, and 8 mol % CO in comparison to the nickel catalyst. High pressure produces a large amount of methane too. The nickel catalyst produces higher syngas at low pressure and 850 °C, and contains 55 mol % H2, 9 mol % CO2, 5 mol % CH4, and 30 mol % CO. Low-pressure gasification produces less amounts of CH4 and CO2. Also, the H2/CO ratio is ∼1.81 using the nickel catalyst at low pressures, which is good for utilizing syngas as a feedstock. These results highlight the importance of catalyst selection, reactor configuration, and operating circumstances in adjusting gasification product composition. The study's findings provide information about optimizing syngas production from pinewood, which is critical for the development of sustainable and efficient energy conversion technologies.

2.
Math Biosci Eng ; 20(8): 14634-14674, 2023 07 05.
Artículo en Inglés | MEDLINE | ID: mdl-37679152

RESUMEN

A nonlinear partial differential equation (PDE) based compartmental model of COVID-19 provides a continuous trace of infection over space and time. Finer resolutions in the spatial discretization, the inclusion of additional model compartments and model stratifications based on clinically relevant categories contribute to an increase in the number of unknowns to the order of millions. We adopt a parallel scalable solver that permits faster solutions for these high fidelity models. The solver combines domain decomposition and algebraic multigrid preconditioners at multiple levels to achieve the desired strong and weak scalabilities. As a numerical illustration of this general methodology, a five-compartment susceptible-exposed-infected-recovered-deceased (SEIRD) model of COVID-19 is used to demonstrate the scalability and effectiveness of the proposed solver for a large geographical domain (Southern Ontario). It is possible to predict the infections for a period of three months for a system size of 186 million (using 3200 processes) within 12 hours saving months of computational effort needed for the conventional solvers.


Asunto(s)
COVID-19 , Humanos , COVID-19/epidemiología , Algoritmos , Geografía , Ontario
3.
HCA Healthc J Med ; 4(2): 157-165, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37424989

RESUMEN

Background: Consensus guidelines on the therapeutic drug monitoring of vancomycin published in 2020 recognize that using the calculated area-under-the-curve (AUC) to guide dosing maximizes clinical efficacy and minimizes risk when compared to traditional trough-based dosing. The purpose of this study was to determine whether AUC monitoring results in reduced acute kidney injury (AKI) rates in adult patients receiving vancomycin for all indications. Methods: In this study, patients 18 years or older who received pharmacist-managed vancomycin therapy were selected using pharmacy surveillance software from 2 timeframes. Patients were excluded if they received less than 48 hours of therapy or had unstable renal function or hemodialysis at baseline. The primary outcome measured was the incidence of AKI in each group of patients. Results: Data were collected for 121 patients in each group. Concomitant nephrotoxins used in each group, as well as the sources of infection, were similar between groups. AUC monitoring did not result in a significant decrease in AKI rate (16.5% in AUC group, 14.9% in trough group; P = .61). However, patients who received AUC monitoring were more likely to be therapeutic at first follow-up compared to the trough monitoring group (43.2% in AUC group, 33.9% in trough group; P = .03). AUC monitoring also resulted in lower trough levels and total daily doses, with no difference in mortality or length of stay. Conclusion: AUC monitoring did not result in an observed decrease in AKI rate. Despite this, the AUC monitoring protocol was effective at reaching the goal AUC of 400-600 mg*hour/L and did not increase mortality or length of stay.

4.
ACS Appl Mater Interfaces ; 15(19): 23255-23264, 2023 05 17.
Artículo en Inglés | MEDLINE | ID: mdl-37134186

RESUMEN

A novel reactor methodology was developed for chemical looping ammonia synthesis processes using microwave plasma for pre-activation of the stable dinitrogen molecule before reaching the catalyst surface. Microwave plasma-enhanced reactions benefit from higher production of activated species, modularity, quick startup, and lower voltage input than competing plasma-catalysis technologies. Simple, economical, and environmentally benign metallic iron catalysts were used in a cyclical atmospheric pressure synthesis of ammonia. Rates of up to 420.9 µmol min-1 g-1 were observed under mild nitriding conditions. Reaction studies showed that both surface-mediated and bulk-mediated reaction domains were found to exist depending on the time under plasma treatment. The associated density functional theory (DFT) calculations indicated that a higher temperature promoted more nitrogen species in the bulk of iron catalysts but the equilibrium limited the nitrogen converion to ammonia, and vice versa. Generation of vibrationally active N2 and, N2+ ions is associated with lower bulk nitridation temperatures and increased nitrogen contents versus thermal-only systems. Additionally, the kinetics of other transition metal chemical looping ammonia synthesis catalysts (Mn and CoMo) were evaluated by high-resolution time-on-stream kinetic analysis and optical plasma characterization. This study sheds new light on phenomena arising in transient nitrogen storage, kinetics, effect of plasma treatment, apparent activation energies, and rate-limiting reaction steps.

5.
ACS Appl Mater Interfaces ; 15(20): 24296-24305, 2023 05 24.
Artículo en Inglés | MEDLINE | ID: mdl-37167454

RESUMEN

Ammonia is emerging as a potential decarbonized H2 energy carrier when produced from renewable energy. The on-site production of liquid ammonia from stranded renewable energy can solve the current energy transportation challenges. The employment of microwave technology can produce the desired ammonia product at milder conditions with the supply of intermittent renewable energy sources. Our previous studies have indicated that the Cs-Ru/CeO2 catalyst is a promising catalyst for microwave-driven ammonia synthesis. In this study, the Cs-Ru/CeO2 catalyst mechanically mixed with carbon nanotubes (CNT) and chemically synthesized using coprecipitation and a hydrothermal method is investigated systematically at low temperatures and atmospheric pressure for microwave-assisted ammonia synthesis. Additionally, the combination of two Ru-based catalysts (Cs-Ru/CeO2 and Cs-Ru/CNT) is studied as well. Mechanical mixing of Cs-Ru/CeO2 with CNT exhibited superior activity as compared to the chemically synthesized Cs-Ru/CeO2-CNT catalyst. Besides the enhancement in dielectric property, the probable synergistic effect leads to increased interfacial polarization at the interface of the mechanically mixed catalyst, improving the overall heating and ammonia production rate. Moreover, the combined Ru-based catalyst also exhibited higher activity as compared to their individual activity toward ammonia synthesis. Numerous characterization techniques were performed, including thermal imaging camera and dielectric measurements, to better understand microwave interaction with the composite catalysts.

6.
BMJ Open ; 12(3): e052681, 2022 03 10.
Artículo en Inglés | MEDLINE | ID: mdl-35273043

RESUMEN

INTRODUCTION: The complex dynamics of the coronavirus disease 2019 (COVID-19) pandemic has made obtaining reliable long-term forecasts of the disease progression difficult. Simple mechanistic models with deterministic parameters are useful for short-term predictions but have ultimately been unsuccessful in extrapolating the trajectory of the pandemic because of unmodelled dynamics and the unrealistic level of certainty that is assumed in the predictions. METHODS AND ANALYSIS: We propose a 22-compartment epidemiological model that includes compartments not previously considered concurrently, to account for the effects of vaccination, asymptomatic individuals, inadequate access to hospital care, post-acute COVID-19 and recovery with long-term health complications. Additionally, new connections between compartments introduce new dynamics to the system and provide a framework to study the sensitivity of model outputs to several concurrent effects, including temporary immunity, vaccination rate and vaccine effectiveness. Subject to data availability for a given region, we discuss a means by which population demographics (age, comorbidity, socioeconomic status, sex and geographical location) and clinically relevant information (different variants, different vaccines) can be incorporated within the 22-compartment framework. Considering a probabilistic interpretation of the parameters allows the model's predictions to reflect the current state of uncertainty about the model parameters and model states. We propose the use of a sparse Bayesian learning algorithm for parameter calibration and model selection. This methodology considers a combination of prescribed parameter prior distributions for parameters that are known to be essential to the modelled dynamics and automatic relevance determination priors for parameters whose relevance is questionable. This is useful as it helps prevent overfitting the available epidemiological data when calibrating the parameters of the proposed model. Population-level administrative health data will serve as partial observations of the model states. ETHICS AND DISSEMINATION: Approved by Carleton University's Research Ethics Board-B (clearance ID: 114596). Results will be made available through future publication.


Asunto(s)
COVID-19 , Algoritmos , Teorema de Bayes , COVID-19/epidemiología , COVID-19/prevención & control , Calibración , Modelos Epidemiológicos , Humanos , SARS-CoV-2
7.
Phys Rev Lett ; 122(24): 241602, 2019 Jun 21.
Artículo en Inglés | MEDLINE | ID: mdl-31322395

RESUMEN

We study whether the relations between the Weyl anomaly, entanglement entropy (EE), and thermal entropy of a two-dimensional (2D) conformal field theory (CFT) extend to 2D boundaries of 3D CFTs, or 2D defects of D≥3 CFTs. The Weyl anomaly of a 2D boundary or defect defines two or three central charges, respectively. One of these, b, obeys a c theorem, as in 2D CFT. For a 2D defect, we show that another, d_{2}, interpreted as the defect's "conformal dimension," must be non-negative if the averaged null energy condition holds in the presence of the defect. We show that the EE of a sphere centered on a planar defect has a logarithmic contribution from the defect fixed by b and d_{2}. Using this and known holographic results, we compute b and d_{2} for 1/2-Bogomol'nyi-Prasad-Sommerfield surface operators in the maximally supersymmetric (SUSY) 4D and 6D CFTs. The results are consistent with b's c theorem. Via free field and holographic examples we show that no universal "Cardy formula" relates the central charges to thermal entropy.

8.
Soc Ment Health ; 9(2): 192-210, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31223514

RESUMEN

Discrimination due to personal characteristics (e.g., gender, sexuality, appearance) is a common yet stressful experience that is detrimental to mental health. Prior work has not considered how spouses in same- and different-sex marriages help each other cope with discrimination despite the importance of marriage for managing stress and adversity. We analyze survey data collected from both spouses in same-sex and different-sex marriages within the United States (N=836 individuals) to examine whether support from spouses weakens the impact of discrimination on depressive symptoms. Results suggest that discrimination contributes to depressive symptoms, but greater support from spouses buffers the mental health consequences of discrimination. Individuals in same-sex marriages report more spousal support than do individuals in different-sex marriages, even after accounting for experiences of discrimination. Same-sex couples may get needed spousal support, whereas women married to men receive the least spousal support and may be vulnerable to stressors that challenge mental health.

9.
Gend Soc ; 32(1): 109-131, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-29520127

RESUMEN

Research on gender inequality within different-sex marriages shows that women do more unpaid labor than men, and that the perception of inequality influences perceptions of marital quality. Yet research on same-sex couples suggests the importance of considering how gender is relational. Past studies show that same-sex partners share unpaid labor more equally and perceive greater equity than do different-sex partners, and that lesbian, gay, and bisexual people are less gender conforming than heterosexuals. However, studies have not considered how gender conformity might shape inequalities and marital quality within same- and different-sex unions. In this study, we analyze dyadic data from both spouses in same- and different-sex marriages to explore how sex of spouse and gender conformity influence perceptions of shared power within the relationship, which, in turn, influences marital quality. Results show that greater gender conformity is related to stronger perceptions of shared power in different-sex and male same-sex couples but not in female same-sex couples. Perceptions of shared power are positively associated with marital quality in all union types. Our findings suggest that maintaining hegemonic masculinity and power inequalities may be salient to marriages with men. In female same-sex couples, gender and its relation to power inequalities may carry less meaning.

10.
Phys Rev Lett ; 115(26): 261601, 2015 Dec 31.
Artículo en Inglés | MEDLINE | ID: mdl-26764985

RESUMEN

We put AdS/CFT dualities involving probe branes to a precision test. On the holographic side we use a new class of supersymmetric D7-brane embeddings into AdS(5)×S(5), which allow us to describe N=4 super Yang-Mills theory coupled to massive N=2 supersymmetric flavors on S(4). With these embeddings we can compare holographic results to a field theory analysis of the free energy using supersymmetric localization. Localization allows us to get results at strong coupling, and hence to compare in detail to AdS/CFT. We find analytically matching results: a phase transition at the same critical mass in both calculations and matching free energies up to a scheme-dependent constant in both phases.

11.
Breast Cancer Res Treat ; 147(1): 119-32, 2014 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-25085752

RESUMEN

BRCA1 and BRCA2 sequencing analysis detects variants of uncertain clinical significance in approximately 2 % of patients undergoing clinical diagnostic testing in our laboratory. The reclassification of these variants into either a pathogenic or benign clinical interpretation is critical for improved patient management. We developed a statistical variant reclassification tool based on the premise that probands with disease-causing mutations are expected to have more severe personal and family histories than those having benign variants. The algorithm was validated using simulated variants based on approximately 145,000 probands, as well as 286 BRCA1 and 303 BRCA2 true variants. Positive and negative predictive values of ≥99 % were obtained for each gene. Although the history weighting algorithm was not designed to detect alleles of lower penetrance, analysis of the hypomorphic mutations c.5096G>A (p.Arg1699Gln; BRCA1) and c.7878G>C (p.Trp2626Cys; BRCA2) indicated that the history weighting algorithm is able to identify some lower penetrance alleles. The history weighting algorithm is a powerful tool that accurately assigns actionable clinical classifications to variants of uncertain clinical significance. While being developed for reclassification of BRCA1 and BRCA2 variants, the history weighting algorithm is expected to be applicable to other cancer- and non-cancer-related genes.


Asunto(s)
Algoritmos , Proteína BRCA1/genética , Proteína BRCA2/genética , Neoplasias de la Mama/clasificación , Neoplasias de la Mama/genética , Predisposición Genética a la Enfermedad , Pruebas Genéticas , Variación Genética/genética , Estudios de Casos y Controles , Femenino , Humanos , Estadificación de Neoplasias , Pronóstico
12.
W V Med J ; 110(1): 16-21, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24640269

RESUMEN

UNLABELLED: Concerns have been raised regarding potential adverse effects and high costs of proton pump inhibitors (PPIs). Our objective was to assess issues of PPI utilization and expense in a large outpatient clinic population. METHODS: Two hundred-fifty-nine outpatient records were reviewed regarding PPI prescribing and indications during 2009. A cost analysis was performed to project cost differences if histamine-2 receptor antagonists (H2RAs) were used as an alternative to PPIs in appropriate clinical situations. RESULTS: Eighty-three (32.0%) were taking PPIs. Problem-listed gastroesophageal reflux disease (GERD) was the primary diagnosis in 69 (83.1%) of patients on PPIs. GERD was not apparent by documented history and/or endoscopy in 46.3% of problem-listed GERD patients. Symptom severity had been documented in only 36.2%. Cost analysis projected substantial savings if H2RAs had been used initially for mild to moderate symptoms. CONCLUSIONS: Outpatient PPI prescribing indications are not well documented and PPI use is probably excessive. H2RA therapy is likely underutilized.


Asunto(s)
Instituciones de Atención Ambulatoria/estadística & datos numéricos , Prescripciones de Medicamentos/economía , Inhibidores de la Bomba de Protones/administración & dosificación , Inhibidores de la Bomba de Protones/economía , Prescripciones de Medicamentos/estadística & datos numéricos , Reflujo Gastroesofágico/tratamiento farmacológico , Antagonistas de los Receptores H2 de la Histamina/administración & dosificación , Antagonistas de los Receptores H2 de la Histamina/economía , Humanos , Estudios Retrospectivos
13.
Front Immunol ; 4: 360, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-24223576

RESUMEN

INTRODUCTION: Autoimmune diseases such as systemic lupus erythematosus, rheumatoid arthritis, and multiple sclerosis affect millions of people worldwide. Interferon regulatory factor 5 (IRF5) contains polymorphisms associated with these autoimmune diseases. Two of these functional polymorphisms are found upstream of the IRF5 gene. rs2004640, which is a single nucleotide polymorphism and the CGGGG insertion/deletion (indel) were studied. IRF5 uses four different promoters for its four first exons: 1A, 1B, 1C, and 1D. Each promoter was analyzed, including functional differences due to the autoimmune-risk polymorphisms. RESULTS: IRF5 promoters were analyzed using ChIP-Seq data (ENCODE database) and the FactorBook database to define transcription factor binding sites. To verify promoter activity, the promoters were cloned into luciferase plasmids. Each construct exhibited luciferase activity. Exons 1A and 1D contain putative PU.1 and NFkB binding sites. Imiquimod, a Toll-like receptor 7 (TLR7) ligand, was used to activate these transcription factors. IRF5 levels were doubled after imiquimod treatment (p < 0.001), with specific increases in the 1A promoter (2.2-fold, p = 0.03) and 1D promoter (2.8-fold, p = 0.03). A putative binding site for p53, which affects apoptosis, was found in the promoter for exon 1B. However, site-directed mutagenesis of the p53 site showed no effect in a reporter assay. CONCLUSION: The IRF5 exon 1B promoter has been characterized, and the responses of each IRF5 promoter to TLR7 stimulation have been determined. Changes in promoter activity and gene expression are likely due to specific and distinct transcription factors that bind to each promoter. Since high expression of IRF5 contributes to the development of autoimmune disease, understanding the source of increased IRF5 levels is key to understanding autoimmune etiology.

14.
Cult Health Sex ; 15(5): 555-69, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23565985

RESUMEN

Most studies on men seeking men and who use the Internet for sexual purposes have focused on the epidemiological outcomes of Internet cruising. Other research has only focused on online sexual behaviours such as cybersex. The present study examines men who find the acts of Internet cruising and emailing to be erotic as self-contained behaviours. We surveyed 499 men who used craigslist.org for sexually-oriented purposes, and ran an ordinary least squares multiple regression model to determine the demographic characteristics of men seeking men who found Internet cruising erotic. Our results showed that younger compared to older men seeking men found the acts erotic. Likewise, men seeking men from mid-sized cities and large cities compared to men from smaller cities found Internet cruising and emailing to be erotic. Most notably, bisexual- and heterosexual-identifying men seeking men compared to gay-identifying men found these acts to be more erotic. Our results suggested that self-contained Internet cruising might provide dual functions. For some men (e.g., heterosexual-identifying men), the behaviour provides a sexual outlet in which fantasy and experimentation may be explored without risking stigmatization. For other men (e.g., those from large cities), the behaviour may be an alternative to offset sexual risk while still being able to 'get off'.


Asunto(s)
Literatura Erótica/psicología , Homosexualidad Masculina/psicología , Internet , Adolescente , Adulto , Anciano , Estudios Transversales , Análisis Factorial , Humanos , Almacenamiento y Recuperación de la Información , Masculino , Persona de Mediana Edad , Análisis Multivariante , Conducta Sexual , Adulto Joven
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