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1.
Energy Policy ; 164: 112906, 2022 May.
Artículo en Inglés | MEDLINE | ID: mdl-35291394

RESUMEN

This paper estimates the impact of the COVID-19 on air travel demand and emissions in Brazil, the largest aviation market in Latin America. Combining detailed flight data and data on combustion emission factors, we estimate the CO2 emissions of domestic flights. A Bayesian structural time-series model was used to estimate the impact of COVID-19 on daily trends of air travel demand and emissions. The COVID-19 caused a reduction of 68% in national passengers and 63% in total CO2 emissions compared to what would have occurred if the pandemic had not happened. Despite such a sharp drop, fuel efficiency decreased after the COVID-19 outbreak, and passenger demand recovered to 64.2% of pre-pandemic levels by the end of 2020. The fast recovery in domestic flights by December 2020 indicates that the emissions could soon return to pre-pandemic levels, demonstrating the challenges of reducing emissions in the aviation sector in the short term.

2.
J Chem Phys ; 153(13): 134705, 2020 Oct 07.
Artículo en Inglés | MEDLINE | ID: mdl-33032413

RESUMEN

Understanding what happens inside the rippling and dancing surface of a liquid remains one of the great challenges of fluid dynamics. Using molecular dynamics, we can pick apart the interface structure and understand surface tension. In this work, we derive an exact mechanical formulation of hydrodynamics for a liquid-vapor interface using a control volume, which moves with the surface. This mathematical framework provides the local definition of hydrodynamic fluxes at any point on the surface. These are represented not only by the flux of molecules and intermolecular interactions acting across the surface but also as a result of the instantaneous local curvature and movement of the surface itself. By explicitly including the surface dynamics in the equations of motion, we demonstrate an exact balance between kinetic and configurational pressure normal to the surface. The hydrodynamic analysis makes no assumptions regarding the probability distribution function, so it is valid for any system arbitrarily far from thermodynamic equilibrium. The presented equations provide a theoretical basis for the study of time-evolving interface phenomena, such as bubble nucleation, droplet dynamics, and liquid-vapor instabilities.

3.
J Chem Phys ; 149(4): 044705, 2018 Jul 28.
Artículo en Inglés | MEDLINE | ID: mdl-30068201

RESUMEN

Inhomogeneous fluids exhibit physical properties that are neither uniform nor isotropic. The pressure tensor is a case in point, key to the mechanical description of the interfacial region. Kirkwood and Buff and, later, Irving and Kirkwood, obtained a formal treatment based on the analysis of the pressure across a planar surface [J. G. Kirkwood and F. P. Buff, J. Chem. Phys. 17(3), 338 (1949); J. H. Irving and J. G. Kirkwood, J. Chem. Phys. 18, 817 (1950)]. We propose a generalisation of Irving and Kirkwood's argument to fluctuating, non-planar surfaces and obtain an expression for the pressure tensor that is not smeared by thermal fluctuations at the molecular scale and corresponding capillary waves [F. P. Buff et al., Phys. Rev. Lett. 15, 621-623 (1965)]. We observe the emergence of surface tension, defined as an excess tangential stress, acting exactly across the dividing surface at the sharpest molecular resolution. The new statistical mechanical expressions extend current treatments to fluctuating inhomogeneous systems far from equilibrium.

4.
J Chem Phys ; 144(4): 044703, 2016 Jan 28.
Artículo en Inglés | MEDLINE | ID: mdl-26827224

RESUMEN

We calculate an atomistically detailed free-energy profile across a heterogeneous system using a nonequilibrium approach. The path-integral formulation of Crooks fluctuation theorem is used in conjunction with the intrinsic sampling method to calculate the free-energy profile for the liquid-vapour interface of the Lennard-Jones fluid. Free-energy barriers are found corresponding to the atomic layering in the liquid phase as well as a barrier associated with the presence of an adsorbed layer as revealed by the intrinsic density profile. Our findings are in agreement with profiles calculated using Widom's potential distribution theorem applied to both the average and the intrinsic profiles as well as the literature values for the excess chemical potential.

5.
J Stroke Cerebrovasc Dis ; 24(2): 507-10, 2015 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-25533759

RESUMEN

BACKGROUND: To characterize atrial ectopic activity in patients with cryptogenic ischemic stroke (CIS) or transient ischemic attack (TIA) and determine its prognostic significance. METHODS: Retrospective cohort study, in which 184 patients with CIS or TIA who had performed 24-hour Holter electrocardiogram were included. The median follow-up was 27.5 months. Baseline clinical and imagiologic characteristics, etiologic investigation results, and ischemic stroke and TIA recurrences information were collected. Number of atrial premature complexes (APCs) per hour was categorized as less than 10 APCs/hour, 10-30 APCs/hour, and more than 30 APCs/hour. RESULTS: Most of the patients had less than 10 APCs/hour (82.6%), 8.2% had 10-30 APCs/hour, and 9.2% had more than 30 APCs/hour. Patients with more than 30 APCs/hour had a greater median left atrium diameter than patients with 30 APCs/hour or less (42 mm vs. 38 mm; 95% confidence interval [CI], .50-7.00; P = .003). Annual recurrence rate of CIS or TIA was 2.9% in patients with less than 10 APCs/hour, 11.0% in 10-30 APCs/hour, and 22.6% in more than 30 APCs/hour (P = .001). More than 30 APCs/hour were independently associated with recurrence risk in multivariate survival analysis (hazard ratio, 3.40; 95% CI, 1.12-10.32; P = .030). CONCLUSIONS: In patients with CIS or TIA, frequent atrial ectopic activity (>30 APCs/h) was independently associated with increased risk of stroke or TIA recurrence. Further studies need to validate frequent atrial ectopic activity as a risk factor for recurrence in cryptogenic stroke and confirm its role as a predictor of occult atrial fibrillation.


Asunto(s)
Fibrilación Atrial/fisiopatología , Isquemia Encefálica/fisiopatología , Atrios Cardíacos/fisiopatología , Ataque Isquémico Transitorio/fisiopatología , Accidente Cerebrovascular/fisiopatología , Adulto , Anciano , Anciano de 80 o más Años , Fibrilación Atrial/complicaciones , Isquemia Encefálica/complicaciones , Electrocardiografía Ambulatoria , Femenino , Humanos , Ataque Isquémico Transitorio/complicaciones , Masculino , Persona de Mediana Edad , Pronóstico , Recurrencia , Estudios Retrospectivos , Factores de Riesgo , Accidente Cerebrovascular/complicaciones
6.
J Chem Phys ; 141(15): 154101, 2014 Oct 21.
Artículo en Inglés | MEDLINE | ID: mdl-25338875

RESUMEN

Molecular Dynamics simulations are performed to study the dynamical properties of molecules in the presence of a liquid-liquid (L/L) interface. In the vicinity of the interface the movement of the particles, coupled with the thermal fluctuations of the interface, can make the evaluation of properties such as the self-diffusion coefficient, particularly difficult. We explore the use of the Evans-Searles Fluctuation Theorem [D. Evans and D. Searles, Phys. Rev. E 50, 1645 (1994)] to obtain dynamical information of molecules in distinct regions of a model L/L system. We demonstrate that it is possible to analyse the effect of the interface on the mobility of molecules using a nonequilibrium approach. This information may provide a valuable insight into the understanding of dynamics of interphase mass transfer.

7.
Curr Probl Cardiol ; 49(4): 102436, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38309545

RESUMEN

BACKGROUND: Transradial access (TRA) is associated with fewer access-related complications, earlier discharge and lower mortality than transfemoral access (TFA), being the preferred route to perform primary percutaneous coronary interventions (PPCIs) in STEMI patients. However, the radial artery is smaller, more superficial and thinner than the femoral artery, which may make PPCIs difficult. PURPOSE: This study describes a practical solution to overcome several of the anatomical difficulties during the TRA, demonstrating its outcomes during clinical practice. METHODS: The authors reviewed the clinical records of 1510 STEMI patients who underwent PPCIs over seven years. Of these, 95 (6.3%) patients experienced problems in advancing a 6F guiding catheter and underwent to STR technique. This technique consists in the use of a longer 5Fr STR flush catheter, which can be used as a "child" type rapid exchange catheter inside the 6Fr guiding catheter, adopting a 5-in-6 Fr technique and creating a smooth distal tip transition of the 6Fr guiding catheter. RESULTS: In 89/95 patients (93.7%), this new technique was successful. The majority of these patients were female (51; 53.7%) and the mean age was 67 ± 14.3 years. The mean reperfusion time since arrival at the catheterization laboratory with STR technique was 24.5 ± 9.9 min, being statistically shorter than when a crossover to TFA was used (29.3 ± 9.5 min; p < 0.017). PPCIs were successfully completed in all different coronary arteries, without complications related to the procedure. CONCLUSIONS: The STR technique is a simple and useful approach that allowed more successful passage of guiding catheters through difficult TRA, allowing a reduction of crossover to TFA in this study to 2.4 %, which translates into a shorter reperfusion time.


Asunto(s)
Intervención Coronaria Percutánea , Infarto del Miocardio con Elevación del ST , Humanos , Masculino , Femenino , Persona de Mediana Edad , Anciano , Anciano de 80 o más Años , Infarto del Miocardio con Elevación del ST/cirugía , Resultado del Tratamiento , Intervención Coronaria Percutánea/métodos , Arteria Radial , Arteria Femoral
8.
Rev Port Cardiol ; 2024 Mar 15.
Artículo en Inglés, Portugués | MEDLINE | ID: mdl-38492801

RESUMEN

INTRODUCTION AND OBJECTIVES: Myocardial infarction with non-obstructive coronary arteries (MINOCA) is responsible for about 10% of all acute myocardial infarctions (AMI). Therapeutic strategies and prognosis depend on the underlying etiology, and a multimodal approach is essential. The objectives of this study were to characterize the group of patients diagnosed with MINOCA and to valuate the diagnostic yield of cardiovascular magnetic resonance (CMR). METHODS: This was a retrospective, observational, and analytical study, including 516 patients admitted for a non-ST-elevation MI and with no significant coronary disease on coronary angiography between January 2016 and September 2021. RESULTS: After the inclusion criteria, 163 patients remained of the 516 admitted to the study. They were divided into four groups based on the CMR results: MINOCA (n=51), Takotsubo syndrome (n=37), myocarditis (n=33), and without diagnosis (n=42). Most patients diagnosed with MINOCA were female with a mean age of 61.06±13.83 years. CMR identified the diagnosis in 74.2% of patients admitted for suspected acute MI, in which coronary angiography showed the absence of significant obstructions. The median time between hospital admission and CMR was significantly shorter in the groups that had a diagnosis compared with the group with no diagnosis (p=0.038), with a significant increase in diagnostic profitability if CMR was performed up to 14 days after admission (p=0.022). There were no deaths of cardiovascular etiology during the follow-up period. CONCLUSIONS: CMR was fundamental as it identified the diagnosis in three out of four patients; it should be performed in the first 14 days.

9.
Cardiovasc Revasc Med ; 59: 93-98, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-37723011

RESUMEN

INTRODUCTION: Clinical events may occur after percutaneous coronary intervention (PCI), particularly in complex lesions and complex patients. The optimization of PCI result, using pressure guidewire and intracoronary imaging techniques, may reduce the risk of these events. The hypothesis of the present study is that the clinical outcome of patients with indication of PCI and coronary stent implantation that are at high risk of events can be improved with an unrestricted use of intracoronary tools that allow PCI optimization. METHODS AND ANALYSIS: Observational prospective multicenter international study, with a follow-up of 12 months, including 1064 patients treated with a cobalt­chromium everolimus-eluting stent. Inclusion criteria include any of the following: Lesion length > 28 mm; Reference vessel diameter < 2.5 mm or > 4.25 mm; Chronic total occlusion; Bifurcation with side branch ≥2.0 mm;Ostial lesion; Left main lesion; In-stent restenosis; >2 lesions stented in the same vessel; Treatment of >2 vessels; Acute myocardial infarction; Renal insufficiency; Left ventricular ejection fraction <30 %; Staged procedure. The control group will be comprised by a similar number of matched patients included in the "extended risk" cohort of the XIENCE V USA study. The primary endpoint will be the 1-year rate of target lesion failure (TLF) (composite of ischemia-driven TLR, myocardial infarction (MI) related to the target vessel, or cardiac death related to the target vessel). Secondary endpoints will include overall mortality, cardiovascular mortality, acute myocardial infarction, TVR, TLR, target vessel failure, and definitive or probable stent thrombosis at 1 year. IMPLICATIONS: The ongoing OPTI-XIENCE study will contribute to the growing evidence supporting the use of intra-coronary imaging techniques for stent optimization in patients with complex coronary lesions.


Asunto(s)
Enfermedad de la Arteria Coronaria , Stents Liberadores de Fármacos , Infarto del Miocardio , Intervención Coronaria Percutánea , Humanos , Enfermedad de la Arteria Coronaria/diagnóstico por imagen , Enfermedad de la Arteria Coronaria/terapia , Enfermedad de la Arteria Coronaria/etiología , Infarto del Miocardio/etiología , Intervención Coronaria Percutánea/efectos adversos , Estudios Prospectivos , Diseño de Prótesis , Sirolimus , Volumen Sistólico , Resultado del Tratamiento , Función Ventricular Izquierda
10.
Arq Bras Cardiol ; 120(1): e20211040, 2023.
Artículo en Inglés, Portugués | MEDLINE | ID: mdl-36629597

RESUMEN

BACKGROUND: Although outcomes in patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary interventions (PCI) have improved, women show higher mortality. OBJECTIVES: To assess gender differences in presentation, management and in-hospital mortality, at 30-days, 6-months and 1-year after STEMI. METHODS: We retrospectively collected data from 809 consecutive patients treated with primary PCI and compared the females versus males at the local intervention cardiology database. The level of significance used was p<0.05. RESULTS: Women were older than man (69,1±14,6 vs. 58,5±12,7 years; p<.001) with higher prevalence of age over 75 years (36.7% vs. 11.7%; p<.001), diabetes (30,6% vs. 18,5%; p=.001), hypertension (60.5% vs. 45.9%; p=.001), chronic kidney disease (3.4% vs. 0.6%; p=.010) and acute ischemic stroke (6.8% vs. 3.0%; p=.021). At presentation, women had more atypical symptoms, less chest pain (p=.014) and were more frequently in cardiogenic shock (p=.011)). Women had longer time until reperfusion (p=.001) and were less likely to receive optimal medical therapy (p<0.05). In-hospital mortality (p=.001), at 30-days (p<.001), 6-months (p<.001) and 1-year (16.4% vs. p<.001) was higher in women. The multivariate analysis identified age over 75 years (HR=4.25; 95% CI[1.67-10.77];p=.002), Killip class II (HR=8.80; 95% CI[2.72-28.41];p<.001), III (HR=5.88; 95% CI [0.99-34.80]; p=.051) and IV (HR=9.60; 95% CI[1.86-48.59];p=.007), Acute Kidney Injury (HR=2.47; 95% CI[1.00-6.13];p=.051) and days of hospitalization (HR=1.04; 95% CI[1.01-1.08];p=.030) but not female gender (HR=0.83; 95% CI[0.33-2.10];p=.690) as independent prognostic factors of mortality. CONCLUSIONS: Compared to men, women with STEMI undergoing primary PCI have higher mortality rates. Women admitted for STEMI have a worse risk profile, are treated with a higher reperfusion time related with system delays and are less likely to receive the recommended therapy. Female gender was not an independent prognostic factor for mortality in the studied population.


FUNDAMENTO: Embora os resultados em pacientes com infarto do miocárdio com supradesnivelamento do segmento ST (IAMCSST) submetidos a intervenções coronárias percutâneas (ICP) primárias tenham melhorado, as mulheres apresentam maior mortalidade. Objetivos: Avaliar as diferenças de gênero na apresentação, manejo e mortalidade hospitalar, em 30 dias, 6 meses e 1 ano após IAMCSST. MÉTODOS: Coletamos retrospectivamente dados de 809 pacientes consecutivos tratados com ICP primária e comparamos mulheres versus homens no banco de dados de cardiologia de intervenção local. O nível de significância utilizado foi p<0,05. RESULTADOS: As mulheres eram mais velhas que os homens (69,1±14,6 vs. 58,5±12,7 anos; p<0,001) com maior prevalência de idade acima de 75 anos (36,7% vs. 11,7%; p<0,001), diabetes (30,6% vs. 18,5%; p=0,001), hipertensão (60,5% vs. 45,9%; p=0,001), doença renal crônica (3,4% vs. 0,6%; p= 0,010) e acidente vascular cerebral isquêmico agudo (6,8% vs. 3,0%; p=0,021). Na apresentação, as mulheres apresentavam mais sintomas atípicos, menos dor torácica (p=0,014) e estavam mais frequentemente em choque cardiogênico (p=0,011)). As mulheres tinham mais tempo até a reperfusão (p=0,001) e eram menos propensas a receber terapia médica ideal (p<0,05). A mortalidade intra-hospitalar (p=0,001), em 30 dias (p<0,001), 6 meses (p<0,001) e 1 ano (16,4% vs. p<0,001) foi maior nas mulheres. A análise multivariada identificou idade acima de 75 anos (HR=4,25; IC 95%[1,67-10,77];p=0,002), classe Killip II (HR=8,80; IC 95%[2,72-28,41];p<0,001), III (HR=5,88; IC95% [0,99-34,80]; p=0,051) e IV (HR=9,60; IC 95%[1,86-48,59];p=0,007), Lesão Renal Aguda (HR=2,47; IC 95% [1,00-6,13];p=0,051) e dias de hospitalização (HR=1,04; IC 95%[1,01-1,08];p=0,030), mas não o sexo feminino (HR=0,83; IC95% [0,33-2,10];p=0,690) como fatores prognósticos independentes de mortalidade. CONCLUSÕES: Comparadas aos homens, as mulheres com IAMCSST submetidas à ICP primária apresentam maiores taxas de mortalidade. Mulheres hospitalizadas por IAMCSST têm pior perfil de risco, são tratadas com maior tempo de reperfusão relacionado a atrasos do sistema e têm menor probabilidade de receber a terapia recomendada. O sexo feminino não foi fator prognóstico independente para mortalidade na população estudada.


Asunto(s)
Accidente Cerebrovascular Isquémico , Infarto del Miocardio , Intervención Coronaria Percutánea , Infarto del Miocardio con Elevación del ST , Humanos , Masculino , Femenino , Anciano , Infarto del Miocardio con Elevación del ST/terapia , Estudios Retrospectivos , Accidente Cerebrovascular Isquémico/etiología , Factores de Riesgo , Resultado del Tratamiento , Mortalidad Hospitalaria
11.
Rev Port Cardiol ; 42(2): 101-110, 2023 02.
Artículo en Inglés, Portugués | MEDLINE | ID: mdl-36243520

RESUMEN

INTRODUCTION: Patients with ST-elevation myocardial infarction (STEMI) requiring inter-hospital transfer for primary percutaneous coronary intervention (PCI) often have delays in reperfusion. The door in-door out (DIDO) time is recommended to be less than 30 min. OBJECTIVES: To assess the DIDO time of hospitals that transfer patients with STEMI to a PCI center and to assess its impact on total ischemia time and clinical outcomes in patients with STEMI. METHODS: We performed a retrospective study of 523 patients with STEMI transferred to a PCI center for primary PCI between January 1, 2013 and June 30, 2017. RESULTS: Median DIDO time was 82 min (interquartile range, 61-132 min). Only seven patients (1.3%) were transferred in ≤30 min. Patients with DIDO times over 60 min had significantly longer system delays (207.3 min vs. 112.7 min; p<0.001) and total ischemia time (344.2 min vs. 222 min; p<0.001) than patients transferred in ≤60 min. Observed in-hospital mortality was significantly higher among patients with DIDO times >60 min vs. ≤60 min (5.1% vs. 0%; p=0.006; adjusted odds ratio for in-hospital mortality, 1.27 [95% CI 1.062-1.432]). By the end of follow-up, patients belonging to the >60 min group had a higher mortality (p=0.016), and survival time was significantly shorter (p=0.011). CONCLUSION: A DIDO time ≤30 min was observed in only a small proportion of patients transferred for primary PCI. DIDO times of ≤60 min were associated with shorter delays in reperfusion, lower in-hospital mortality and longer survival times.


Asunto(s)
Intervención Coronaria Percutánea , Infarto del Miocardio con Elevación del ST , Humanos , Infarto del Miocardio con Elevación del ST/cirugía , Infarto del Miocardio con Elevación del ST/etiología , Intervención Coronaria Percutánea/efectos adversos , Estudios Retrospectivos , Factores de Tiempo , Transferencia de Pacientes
12.
Rev Port Cardiol ; 42(1): 71.e1-71.e6, 2023 01.
Artículo en Inglés, Portugués | MEDLINE | ID: mdl-36442584

RESUMEN

We report the case of a 17-year-old athlete who resorted to the emergency department for palpitations and dizziness while exercising. He mentioned two exercise-associated episodes of syncope in the last six months. He was tachycardic and hypotensive. The electrocardiogram showed regular wide complex tachycardia, left bundle branch block morphology with superior axis restored to sinus rhythm after electrical cardioversion. In sinus rhythm, it showed T-wave inversion in V1-V5. Transthoracic echocardiography revealed mild dilation and dysfunction of the right ventricle (RV) with global hypocontractility. Cardiac magnetic resonance (CMR) revealed a RV end diastolic volume indexed to body surface area of 180 ml/m2, global hypokinesia and RV dyssynchrony, subepicardial late enhancement in the distal septum and in the middle segment of the inferoseptal wall. The patient underwent a genetic study which showed a mutation in the gene that encodes the desmocolin-2 protein (DSC-2), which is involved in the pathogenesis of arrhythmogenic right ventricular cardiomyopathy (ARVC). According to the modified Task Force Criteria for this diagnosis, the patient presented four major criteria for ARVC. Thus, a subcutaneous cardioverter was implanted, and the patient was followed up at the cardiology department. Arrhythmogenic right ventricular cardiomyopathy diagnosis is based on structural, functional, electrophysiological and genetic criteria reflecting underlying histological changes. This case depicts the essential characteristics for disease recognition.


Asunto(s)
Displasia Ventricular Derecha Arritmogénica , Masculino , Humanos , Adolescente , Displasia Ventricular Derecha Arritmogénica/complicaciones , Displasia Ventricular Derecha Arritmogénica/diagnóstico , Electrocardiografía , Ventrículos Cardíacos/diagnóstico por imagen , Ecocardiografía , Arritmias Cardíacas , Síncope/etiología
13.
Rev Port Cardiol ; 42(1): 1-6, 2023 01.
Artículo en Inglés, Portugués | MEDLINE | ID: mdl-36043164

RESUMEN

INTRODUCTION: The COVID-19 pandemic has imposed an unprecedented burden on healthcare systems worldwide, changing the profile of interventional cardiology activity. OBJECTIVES: To quantify and compare the number of percutaneous coronary interventions (PCIs) performed for acute and chronic coronary syndromes during the first COVID-19 outbreak with the corresponding period in previous years. METHODS: Data on PCI from the prospective multicenter Portuguese Registry on Interventional Cardiology (RNCI) were used to analyze changes in PCI for ST-elevation myocardial infarction (STEMI), non-ST-elevation acute coronary syndromes (NSTE-ACS) and chronic coronary syndromes (CCS). The number of PCIs performed during the initial period of the COVID-19 outbreak in Portugal, from March 1 to May 2, 2020, was compared with the mean frequency of PCIs performed during the corresponding period in the previous three years (2017-2019). RESULTS: The total number of PCIs procedures was significantly decreased during the initial COVID-19 outbreak in Portugal (-36%, p<0.001). The reduction in PCI procedures for STEMI, NSTE-ACS and CCS was, respectively, -25% (p<0.019), -20% (p<0.068) and -59% (p<0.001). CONCLUSIONS: Compared with the corresponding period in the previous three years, the number of PCI procedures performed for STEMI and CCS decreased markedly during the first wave of the COVID-19 pandemic in Portugal.


Asunto(s)
Síndrome Coronario Agudo , COVID-19 , Intervención Coronaria Percutánea , Infarto del Miocardio con Elevación del ST , Humanos , Intervención Coronaria Percutánea/métodos , Portugal/epidemiología , Infarto del Miocardio con Elevación del ST/epidemiología , Infarto del Miocardio con Elevación del ST/cirugía , Estudios Prospectivos , Pandemias
14.
J Chem Phys ; 137(6): 064116, 2012 Aug 14.
Artículo en Inglés | MEDLINE | ID: mdl-22897264

RESUMEN

We present the results obtained from a systematic equilibrium molecular dynamics study of the effect of torsional flexibility on the diffusion and viscosity of a series of linear alkanes. To make unambiguous comparisons between molecules with torsional flexibility and those without, we use the frozen distribution sampling (FDS) method introduced by Travis et al. [J. Chem. Phys. 98, 1524 (1993); J. Chem. Phys. 102, 2174 (1995)] but modified and updated for increased efficiency. We first demonstrate comprehensively that FDS guarantees corresponding thermodynamic states. We then show that removal of torsional flexibility results in a significant lowering of the diffusion coefficient (and corresponding increase in shear viscosity) and furthermore that this effect increases with increasing chain length. The results are discussed in terms of the possible mechanism giving rise to this dynamic coupling phenomenon.

15.
Soc Sci Med ; 273: 113773, 2021 03.
Artículo en Inglés | MEDLINE | ID: mdl-33609968

RESUMEN

The rapid spread of COVID-19 across the world has raised concerns about the responsiveness of cities and healthcare systems during pandemics. Recent studies try to model how the number of COVID-19 infections will likely grow and impact the demand for hospitalization services at national and regional levels. However, less attention has been paid to the geographic access to COVID-19 healthcare services and to hospitals' response capacity at the local level, particularly in urban areas in the Global South. This paper shows how transport accessibility analysis can provide actionable information to help improve healthcare coverage and responsiveness. It analyzes accessibility to COVID-19 healthcare at high spatial resolution in the 20 largest cities of Brazil. Using network-distance metrics, we estimate the vulnerable population living in areas with poor access to healthcare facilities that could either screen or hospitalize COVID-19 patients. We then use a new balanced floating catchment area (BFCA) indicator to estimate spatial, income, and racial inequalities in access to hospitals with intensive care unit (ICU) beds and mechanical ventilators while taking into account congestion effects. Based on this analysis, we identify substantial social and spatial inequalities in access to health services during the pandemic. The availability of ICU equipment varies considerably between cities, and it is substantially lower among black and poor communities. The study maps territorial inequalities in healthcare access and reflects on different policy lessons that can be learned for other countries based on the Brazilian case.


Asunto(s)
COVID-19 , Áreas de Influencia de Salud , Accesibilidad a los Servicios de Salud , Pandemias , Brasil , Humanos , SARS-CoV-2
16.
Rev Port Cardiol (Engl Ed) ; 40(8): 525-536, 2021 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-34392892

RESUMEN

BACKGROUND: Iron deficiency (IDef) is a prevalent condition in patients with heart disease and in those with heart failure (HF). Evidence has shown that this deficit is associated with worse prognosis. Data in literature are scarce on the prognostic impact of IDef in acute coronary syndromes (ACS), which is the main objective of this study. METHODS: Observational, retrospective study which included 817 patients admitted for ACS. Two groups were defined according to the presence (n=298) or absence of IDef (n=519) on admission. The clinical event under study was the occurrence of death or severe HF in the long term. Independent predictors of prognosis were determined with logistic regression analysis. RESULTS: Thirty-six percent of patients had IDef. There was higher mortality (p=0.004), higher incidence of HF (p=0.011) during follow-up and a higher rate of hospital readmissions (p=0.048) in this group. IDef was an independent predictor of death or severe HF in follow-up, along with anemia, left ventricular dysfunction, renal dysfunction and the absence of revascularization. IDef also enabled us to further stratify the prognosis of patients without anemia based on the occurrence of death or severe HF and those with lower Killip classes (≤2) based on the occurrence of death. CONCLUSION: IDef was an independent predictor of death or severe HF in patients admitted with ACS and enabled additional stratification for those without anemia on admission and in those with Killip classes ≤2.


Asunto(s)
Síndrome Coronario Agudo , Anemia Ferropénica , Insuficiencia Cardíaca , Síndrome Coronario Agudo/diagnóstico , Anemia Ferropénica/epidemiología , Insuficiencia Cardíaca/epidemiología , Humanos , Pronóstico , Estudios Retrospectivos
17.
BMJ Glob Health ; 6(4)2021 04.
Artículo en Inglés | MEDLINE | ID: mdl-33926892

RESUMEN

INTRODUCTION: Little evidence exists on the differential health effects of COVID-19 on disadvantaged population groups. Here we characterise the differential risk of hospitalisation and death in São Paulo state, Brazil, and show how vulnerability to COVID-19 is shaped by socioeconomic inequalities. METHODS: We conducted a cross-sectional study using hospitalised severe acute respiratory infections notified from March to August 2020 in the Sistema de Monitoramento Inteligente de São Paulo database. We examined the risk of hospitalisation and death by race and socioeconomic status using multiple data sets for individual-level and spatiotemporal analyses. We explained these inequalities according to differences in daily mobility from mobile phone data, teleworking behaviour and comorbidities. RESULTS: Throughout the study period, patients living in the 40% poorest areas were more likely to die when compared with patients living in the 5% wealthiest areas (OR: 1.60, 95% CI 1.48 to 1.74) and were more likely to be hospitalised between April and July 2020 (OR: 1.08, 95% CI 1.04 to 1.12). Black and Pardo individuals were more likely to be hospitalised when compared with White individuals (OR: 1.41, 95% CI 1.37 to 1.46; OR: 1.26, 95% CI 1.23 to 1.28, respectively), and were more likely to die (OR: 1.13, 95% CI 1.07 to 1.19; 1.07, 95% CI 1.04 to 1.10, respectively) between April and July 2020. Once hospitalised, patients treated in public hospitals were more likely to die than patients in private hospitals (OR: 1.40%, 95% CI 1.34% to 1.46%). Black individuals and those with low education attainment were more likely to have one or more comorbidities, respectively (OR: 1.29, 95% CI 1.19 to 1.39; 1.36, 95% CI 1.27 to 1.45). CONCLUSIONS: Low-income and Black and Pardo communities are more likely to die with COVID-19. This is associated with differential access to quality healthcare, ability to self-isolate and the higher prevalence of comorbidities.


Asunto(s)
COVID-19/etnología , COVID-19/mortalidad , Etnicidad/estadística & datos numéricos , Mortalidad Hospitalaria/etnología , Neumonía Viral , Áreas de Pobreza , Características de la Residencia/estadística & datos numéricos , Adulto , Anciano , Anciano de 80 o más Años , Brasil/epidemiología , Estudios Transversales , Femenino , Disparidades en el Estado de Salud , Humanos , Masculino , Persona de Mediana Edad , Pandemias , Neumonía Viral/epidemiología , SARS-CoV-2 , Estudios Seroepidemiológicos , Factores Socioeconómicos
18.
Am J Infect Control ; 49(4): 512-515, 2021 04.
Artículo en Inglés | MEDLINE | ID: mdl-33080363

RESUMEN

This study assessed the disinfection using 70% ethanol; H2O2-quaternary ammonium salt mixture; 0.1% sodium hypochlorite and autoclaving of four 3D-printed face shields with different designs, visor materials; and visor thickness (0.5-0.75 mm). We also investigated their clinical suitability by applying a questionnaire to health workers (HW) who used them. Each type of disinfection was done 40 times on each type of mask without physical damage. In contrast, autoclaving led to appreciable damage.


Asunto(s)
COVID-19/prevención & control , Desinfectantes/farmacología , Desinfección/métodos , Equipo de Protección Personal/virología , Impresión Tridimensional , SARS-CoV-2 , COVID-19/epidemiología , Recolección de Datos , Diseño de Equipo , Etanol/farmacología , Personal de Salud , Humanos , Peróxido de Hidrógeno/farmacología , Hipoclorito de Sodio/farmacología
19.
Arch Cardiol Mex ; 90(1): 8-15, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-31996867

RESUMEN

Background: Different mechanical properties have been suggested for metallic bioresorbable vascular scaffolds (BVS) in comparison to polymeric BVS. We aim to evaluate the acute mechanical performance of Magmaris® scaffold in comparison to Absorb®. Materials and Methods: Two groups of 10 coronary lesions treated with Magmaris® and Absorb® 1.1 (20584 vs. 21016 struts) were compared. In all cases, optical coherence tomographic (OCT) images were acquired after scaffold deployment. Baseline clinical, angiographic, and procedural characteristics were compared, including OCT evaluations. Results: No baseline clinical or angiographic significant differences were found between groups. The most common indication for revascularization was effort angina (60% vs. 70% p = 0.45) with no ST-elevation myocardial infarction (MI) cases. Main target artery was left anterior descending, with a mean vessel diameter of 3.46 ± 0.23 in Absorb® and 3.52 ± 0.19mm in Magmaris® groups (p = 0.56). All cases underwent pre- and post-dilatation with a procedural success rate of 100%. OCT analyses showed larger scaffold and vessel diameters in Magmaris® group: 3.11 ± 0.38 mm versus 3.07 ± 0.36 mm, p = 0.03 and 4.12 ± 0.51 mm versus 4.04 ± 0.46 mm, p = 0.04. Despite the application of slightly higher postdilatation pressures to Magmaris® devices (18.01 ± 2.15 vs. 17.20 ± 3.80 atm, p = 0.05), significantly lower percentages of disrupted and malapposed struts were identified within Magmaris® scaffolds (0.15% vs. 0.27%, p = 0.03 and 1.06% vs. 1.46% p = 0.01). No cardiac death, target vessel-related MI, or clinically driven target lesion revascularization was reported in a 30-day follow-up. Conclusion: Mechanical properties of Magmaris® scaffold allow achieving larger vessel and scaffold diameters in a safe manner, with lower rates of malapposition and scaffold disruption.


Introducción: Se ha sugerido la presencia de un distinto comportamiento mecánico entre los dos grupos principales de dispositivos bioresorbibles: metálicos y poliméricos. En este estudio evaluamos el comportamiento mecánico agudo del andamiaje bioresorbible metálico Magmaris® frente al del polimérico Absorb®. Métodos: Se compararon dos grupos de 10 lesiones coronarias tratadas con Magmaris® y Absorb® 1.1 (20584 vs. 21016 struts). En todos los casos se realizó estudio postimplante del dispositivo mediante tomografia de coherencia óptica (OCT). Se compararon las características basales clínicas y angiográficas, así como aspectos del procedimiento (incluídos los estudios de OCT) entre ambos grupos. Resultados: No se encontraron diferencias clínicas o angiográficas estadísticamente significativas entre ambos grupos. La indicación más frecuente de revascularización coronaria fué la presencia de angina de esfuerzo (60% vs. 70% p = 0.45), sin incluirse casos de IAMCEST. La arteria descendente anterior fué el principal vaso diana, con un diámetro medio de 3.46 ± 0.23 mm en el grupo de Absorb® y de 3.52 ± 0.19mm en el grupo de Magmaris® (p = 0.56). En todos los casos se realizó pre y postdilatación, con una tasa de éxito del procedimiento del 100%. Los estudios mediante OCT demostraron un mayor diámetro de stent y del vaso en el grupo de Magmaris®: 3.11 ± 0.38mm versus 3.07 ± 0.36 mm, p = 0.03 y 4.12 ± 0.51mm versus 4.04 ± 0.46mm, p = 0.04. A pesar de someter a los dispositivos Magmaris® a presiones de postdilatación ligeramente superiores (18.01 ± 2.15 vs. 17.20 ± 3.80 atm, p = 0.05), se identificó un menor porcentaje estadísticamente significativo de struts rotos o malapuestos en dicho grupo (0.15% vs. 0.27 %, p = 0.03 y 1.06 % vs. 1.46% p = 0.01). En un seguimiento a 30 días no se registraron eventos mayores: muerte cardíaca, IM relacionado con vaso diana o TLR. Conclusión: Las propiedades mecánicas del scaffold metálico bioresorbible Magmaris® permiten alcanzar mayores diámetros de stent y vaso de forma segura tras su implante, con una baja tasa de malaposición y disrupción.


Asunto(s)
Implantes Absorbibles , Enfermedad de la Arteria Coronaria/cirugía , Stents Liberadores de Fármacos , Andamios del Tejido , Anciano , Angiografía Coronaria , Enfermedad de la Arteria Coronaria/diagnóstico por imagen , Femenino , Humanos , Magnesio/química , Masculino , Persona de Mediana Edad , Poliésteres/química , Diseño de Prótesis , Estudios Retrospectivos , Tomografía de Coherencia Óptica , Resultado del Tratamiento
20.
Nat Hum Behav ; 4(8): 856-865, 2020 08.
Artículo en Inglés | MEDLINE | ID: mdl-32737472

RESUMEN

The first case of COVID-19 was detected in Brazil on 25 February 2020. We report and contextualize epidemiological, demographic and clinical findings for COVID-19 cases during the first 3 months of the epidemic. By 31 May 2020, 514,200 COVID-19 cases, including 29,314 deaths, had been reported in 75.3% (4,196 of 5,570) of municipalities across all five administrative regions of Brazil. The R0 value for Brazil was estimated at 3.1 (95% Bayesian credible interval = 2.4-5.5), with a higher median but overlapping credible intervals compared with some other seriously affected countries. A positive association between higher per-capita income and COVID-19 diagnosis was identified. Furthermore, the severe acute respiratory infection cases with unknown aetiology were associated with lower per-capita income. Co-circulation of six respiratory viruses was detected but at very low levels. These findings provide a comprehensive description of the ongoing COVID-19 epidemic in Brazil and may help to guide subsequent measures to control virus transmission.


Asunto(s)
Betacoronavirus/aislamiento & purificación , Infecciones por Coronavirus , Transmisión de Enfermedad Infecciosa , Gripe Humana , Pandemias , Neumonía Viral , Adulto , Anciano , Brasil/epidemiología , COVID-19 , Prueba de COVID-19 , Niño , Técnicas de Laboratorio Clínico/métodos , Técnicas de Laboratorio Clínico/estadística & datos numéricos , Coinfección/epidemiología , Infecciones por Coronavirus/diagnóstico , Infecciones por Coronavirus/tratamiento farmacológico , Infecciones por Coronavirus/mortalidad , Infecciones por Coronavirus/terapia , Infecciones por Coronavirus/transmisión , Transmisión de Enfermedad Infecciosa/prevención & control , Transmisión de Enfermedad Infecciosa/estadística & datos numéricos , Femenino , Hospitalización/estadística & datos numéricos , Humanos , Lactante , Gripe Humana/diagnóstico , Gripe Humana/epidemiología , Gripe Humana/virología , Masculino , Mortalidad , Neumonía Viral/diagnóstico , Neumonía Viral/mortalidad , Neumonía Viral/terapia , Neumonía Viral/transmisión , SARS-CoV-2 , Factores Socioeconómicos , Tratamiento Farmacológico de COVID-19
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