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1.
J Phys Chem B ; 128(2): 551-566, 2024 Jan 18.
Artículo en Inglés | MEDLINE | ID: mdl-38181201

RESUMEN

This work reports the computation and modeling of the self-diffusivity (D*), shear viscosity (η*), and thermal conductivity (κ*) of the Mie fluid. The transport properties were computed using equilibrium molecular dynamics simulations for the Mie fluid with repulsive exponents (λr) ranging from 7 to 34 and at a fixed attractive exponent (λa) of 6 over the whole fluid density (ρ*) range and over a wide temperature (T*) range. The computed database consists of 17,212, 14,288, and 13,099 data points for self-diffusivity, shear viscosity, and thermal conductivity, respectively. The database is successfully validated against published simulation data. The above-mentioned transport properties are correlated using artificial neural networks (ANNs). Two modeling approaches were tested: a semiempirical formulation based on entropy scaling and an empirical formulation based on density and temperature as input variables. For the former, it was found that a unique formulation based on entropy scaling does not yield satisfactory results over the entire density range due to a divergent and incorrect scaling of the transport properties at low densities. For the latter empirical modeling approach, it was found that regularizing the data, e.g., modeling ρ*D* instead of D*, ln η* instead of η*, and ln κ* instead of κ*, as well as using the inverse of the temperature as an input feature, helps to ease the interpolation efforts of the artificial neural networks. The trained ANNs can model seen and unseen data over a wide range of density and temperature. Ultimately, the ANNs can be used alongside equations of state to regress effective force field parameters from volumetric and transport data.

2.
J Chem Phys ; 158(18)2023 May 14.
Artículo en Inglés | MEDLINE | ID: mdl-37161943

RESUMEN

A procedure for deriving thermodynamically consistent data-driven equations of state (EoS) for fluids is presented. The method is based on fitting the Helmholtz free energy using artificial neural networks to obtain a closed-form relationship between the thermophysical properties of fluids (FE-ANN EoS). As a proof-of-concept, an FE-ANN EoS is developed for the Mie fluids, starting from a database obtained by classical molecular dynamics simulations. The FE-ANN EoS is trained using first- (pressure and internal energy) and second-order (e.g., heat capacities, Joule-Thomson coefficients) derivative data. Additional constraints ensure that the data-driven model fulfills thermodynamically consistent limits and behavior. The results for the FE-ANN EoS are shown to be as accurate as the best available analytical model while being developed in a fraction of the time. The robustness of the "digital" equation of state is exemplified by computing physical behavior it has not been trained on, for example, fluid phase equilibria. Furthermore, the model's internal consistency is successfully assessed using Brown's characteristic curves.

3.
Am J Infect Control ; 49(10): 1267-1274, 2021 10.
Artículo en Inglés | MEDLINE | ID: mdl-33901588

RESUMEN

BACKGROUND: We report the results of INICC surveillance study from 2013 to 2018, in 664 intensive care units (ICUs) in 133 cities, of 45 countries, from Latin-America, Europe, Africa, Eastern-Mediterranean, Southeast-Asia, and Western-Pacific. METHODS: Prospective data from patients hospitalized in ICUs were collected through INICC Surveillance Online System. CDC-NHSN definitions for device-associated healthcare-associated infection (DA-HAI) were applied. RESULTS: We collected data from 428,847 patients, for an aggregate of 2,815,402 bed-days, 1,468,216 central line (CL)-days, 1,053,330 mechanical ventilator (MV)-days, 1,740,776 urinary catheter (UC)-days. We found 7,785 CL-associated bloodstream infections (CLAB), 12,085 ventilator-associated events (VAE), and 5,509 UC-associated urinary tract infections (CAUTI). Pooled DA-HAI rates were 5.91% and 9.01 DA-HAIs/1,000 bed-days. Pooled CLAB rate was 5.30/1,000 CL-days; VAE rate was 11.47/1,000 MV-days, and CAUTI rate was 3.16/1,000 UC-days. P aeruginosa was non-susceptible (NS) to imipenem in 52.72% of cases; to colistin in 10.38%; to ceftazidime in 50%; to ciprofloxacin in 40.28%; and to amikacin in 34.05%. Klebsiella spp was NS to imipenem in 49.16%; to ceftazidime in 78.01%; to ciprofloxacin in 66.26%; and to amikacin in 42.45%. coagulase-negative Staphylococci and S aureus were NS to oxacillin in 91.44% and 56.03%, respectively. Enterococcus spp was NS to vancomycin in 42.31% of the cases. CONCLUSIONS: DA-HAI rates and bacterial resistance are high and continuous efforts are needed to reduce them.


Asunto(s)
Infecciones Bacterianas , Infecciones Relacionadas con Catéteres , Infección Hospitalaria , Neumonía Asociada al Ventilador , Infecciones Urinarias , Adulto , Infecciones Bacterianas/epidemiología , Infecciones Relacionadas con Catéteres/epidemiología , Niño , Infección Hospitalaria/epidemiología , Humanos , Control de Infecciones , Unidades de Cuidados Intensivos , Neumonía Asociada al Ventilador/epidemiología , Estudios Prospectivos , Infecciones Urinarias/epidemiología
4.
Infect Control Hosp Epidemiol ; 42(9): 1098-1104, 2021 09.
Artículo en Inglés | MEDLINE | ID: mdl-33441207

RESUMEN

BACKGROUND: Data on short-term peripheral intravenous catheter-related bloodstream infections per 1,000 peripheral venous catheter days (PIVCR BSIs per 1,000 PVC days) rates from Latin America are not available, so they have not been thoroughly studied. METHODS: International Nosocomial Infection Control Consortium (INICC) members conducted a prospective, surveillance study on PIVCR BSIs from January 2010 to March 2018 in 100 intensive care units (ICUs) among 41 hospitals, in 26 cities of 9 countries in Latin America (Argentina, Brazil, Colombia, Costa Rica, Dominican-Republic, Ecuador, Mexico, Panama, and Venezuela). The Centers for Disease Control and Prevention (CDC) National Health Safety Network (NHSN) definitions were applied, and INICC methodology and INICC Surveillance Online System software were used. RESULTS: In total, 10,120 ICU patients were followed for 40,078 bed days and 38,262 PVC days. In addition, 79 PIVCR BSIs were identified, with a rate of 2.06 per 1,000 PVC days (95% confidence interval [CI], 1.635-2.257). The average length of stay (ALOS) of patients without a PIVCR BSI was 3.95 days, and the ALOS was 5.29 days for patients with a PIVCR BSI. The crude extra ALOS was 1.34 days (RR, 1.33; 95% CI, 1.0975-1.6351; P = .040).The mortality rate in patients without PIVCR BSI was 3.67%, and this rate was 6.33% in patients with a PIVCR BSI. The crude extra mortality was 1.70 times higher. The microorganism profile showed 48.5% gram-positive bacteria (coagulase-negative Staphylococci 25.7%) and 48.5% gram-negative bacteria: Acinetobacter spp, Escherichia coli, and Klebsiella spp (8.5% each one), Pseudomonas aeruginosa (5.7%), and Candida spp (2.8%). The resistances of Pseudomonas aeruginosa were 0% to amikacin and 50% to meropenem. The resistance of Acinetobacter baumanii to amikacin was 0%, and the resistance of coagulase-negative Staphylococcus to oxacillin was 75%. CONCLUSIONS: Our PIVCR BSI rates were higher than rates from more economically developed countries and were similar to those of countries with limited resources.


Asunto(s)
Infección Hospitalaria , Sepsis , Argentina , Brasil , Catéteres , Colombia , Costa Rica , Infección Hospitalaria/epidemiología , República Dominicana/epidemiología , Ecuador/epidemiología , Humanos , Unidades de Cuidados Intensivos , América Latina/epidemiología , México , Panamá , Estudios Prospectivos , Venezuela
5.
J Comput Chem ; 41(29): 2504-2526, 2020 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-32871019

RESUMEN

Phasepy is a Python based package for fluid phase equilibria and interfacial properties calculation from equation of state (EoS). Phasepy uses several tools (i.e., NumPy, SciPy, Pandas, Matplotlib) allowing use Phasepy under Jupyter Notebooks. Phasepy models phase equilibria with the traditional ϕ-γ and ϕ-ϕ approaches, where ϕ (fugacity coefficient) can be modeled as a perfect gas, virial gas or EoS fluid, whereas γ (activity coefficient) can be described by conventional models (NRTL, Wilson, Redlich-Kister expansion, and the group contribution modified-UNIFAC). Interfacial properties are based on the square gradient theory couple to ϕ-ϕ approach. The available EoSs are the cubic EoS family extended to mixtures through the quadratic, modified-Huron-Vidal, and Wong-Sandler mixing rules. Phasepy allows to analyze phase stability, compute phase equilibria, interfacial properties, and optimize their parameters for vapor-liquid, liquid-liquid, and vapor-liquid-liquid equilibria for multicomponent mixtures. Phasepy implementation, and robustness are illustrated for binary and ternary mixtures.

6.
Molecules ; 25(7)2020 Mar 25.
Artículo en Inglés | MEDLINE | ID: mdl-32218362

RESUMEN

Interfacial properties such as interfacial profiles, surface activity, wetting transitions, and interfacial tensions along the three-phase line are described for a Type IIIa binary mixture. The methodological approach combines the square gradient theory coupled to the statistical associating fluid theory for Mie potentials of variable range, and coarse-grained molecular dynamics simulations using the same underlying potential. The water + n-hexane mixture at three-phase equilibrium is chosen as a benchmark test case. The results show that the use of the same molecular representation for both the theory and the simulations provides a complementary picture of the aforementioned mixture, with an excellent agreement between the molecular models and the available experimental data. Interfacial tension calculations are extended to temperatures where experimental data are not available. From these extrapolations, it is possible to infer a first order wetting transition at 347.2 K, where hexane starts to completely wet the water/vapor interface. Similarly, the upper critical end point is estimated at 486.3 K. Both results show a very good agreement to the available experimental information. The concentration profiles confirm the wetting behavior of n-hexane along with a strong positive surface activity that increases with temperature, contrasting the weak positive surface activity of water that decreases with temperature.


Asunto(s)
Termodinámica , Modelos Químicos , Simulación de Dinámica Molecular , Tensión Superficial
7.
Actual. SIDA. infectol ; 27(100): 45-51, 20190000. tab
Artículo en Español | LILACS, BINACIS | ID: biblio-1354078

RESUMEN

El rol de los virus respiratorios distintos de influenza en las infecciones respiratorias agudas en los adultos mayores ha sido probablemente subestimado. En los últimos años, los avances en técnicas moleculares de diagnóstico han hecho posible la identificación rápida del virus sincicial respiratorio humano (HRSV). Realizamos un estudio prospectivo observacional para evaluar el rol del HRSV en mayores de 65 años que se hospitalizaron por infecciones respiratorias en nuestra institución, ubicada en la ciudad de La Plata, provincia de Buenos Aires. Fueron reclutados 124 pacientes y el HRSV se detectó en 13, influenza B en 9 e influenza A en 8. La presentación clínica más frecuente de los The role of respiratory viruses other than influenza in acute respiratory tract infections among elderly adults has probably been underestimated. Recent advances in molecular diagnosis have made the rapid identification of human respiratory syncitial virus HRSV infection possible. We conducted a prospective observational study to evaluate the role of HRSV in elderly patients (>65 years of age) hospitalized for acute respiratory infections. A total of 124 patients were recruited, HRSV infection was identified in 13 patients, Influenza B in 9 patients and influenza A in 8 patients. The most frequent clinical presentation was bronchospasm and the infection was prevalent in patients with comorbidities. HRSV infections accounted for an important number of hospital admissions and has been associated with high mortality rates (23%). pacientes con HRSV fue el broncoespasmo y afectó principalmente a personas con comorbilidades. HRSV fue responsable de un número importante de internaciones por enfermedad respiratoria aguda en mayores de 65 años en nuestra institución y se asoció a mortalidad elevada (23%).


The role of respiratory viruses other than influenza in acute respiratory tract infections among elderly adults has probably been underestimated. Recent advances in molecular diagnosis have made the rapid identification of human respiratory syncitial virus HRSV infection possible. We conducted a prospective observational study to evaluate the role of HRSV in elderly patients (>65 years of age) hospitalized for acute respiratory infections. A total of 124 patients were recruited, HRSV infection was identified in 13 patients, Influenza B in 9 patients and influenza A in 8 patients. The most frequent clinical presentation was bronchospasm and the infection was prevalent in patients with comorbidities. HRSV infections accounted for an important number of hospital admissions and has been associated with high mortality rates (23%).


Asunto(s)
Humanos , Anciano , Anciano de 80 o más Años , Estudios Prospectivos , Estudios de Cohortes , Virus Sincitial Respiratorio Humano/inmunología , Infecciones por Virus Sincitial Respiratorio/etiología , Infecciones por Virus Sincitial Respiratorio/epidemiología , Pneumovirinae/inmunología , Hospitalización/estadística & datos numéricos
8.
Infect Control Hosp Epidemiol ; 39(4): 445-451, 2018 04.
Artículo en Inglés | MEDLINE | ID: mdl-29427997

RESUMEN

OBJECTIVE To analyze the impact of the International Nosocomial Infection Control Consortium (INICC) Multidimensional Approach (IMA) and the INICC Surveillance Online System (ISOS) on central line-associated bloodstream infection (CLABSI) rates in 14 intensive care units (ICUs) in Argentina from January 2014 to April 2017. DESIGN This prospective, pre-post surveillance study of 3,940 ICU patients was conducted in 11 hospitals in 5 cities in Argentina. During our baseline evaluation, we performed outcome and process surveillance of CLABSI applying Centers for Disease Control and Prevention/National Health Safety Network (CDC/NHSN) definitions. During the intervention, we implemented the IMA through ISOS: (1) a bundle of infection prevention practice interventions, (2) education, (3) outcome surveillance, (4) process surveillance, (5) feedback on CLABSI rates and consequences, and (6) performance feedback of process surveillance. Bivariate and multivariate regression analyses were performed using a logistic regression model to estimate the effect of the intervention on the CLABSI rate. RESULTS During the baseline period, 5,118 CL days and 49 CLABSIs were recorded, for a rate of 9.6 CLABSIs per 1,000 central-line (CL) days. During the intervention, 15,659 CL days and 68 CLABSIs were recorded, for a rate of 4.1 CLABSIs per 1,000 CL days. The CLABSI rate was reduced by 57% (incidence density rate: 0.43; 95% confidence interval, 0.34-0.6; P<.001). CONCLUSIONS Implementing IMA through ISOS was associated with a significant reduction in the CLABSI rate in ICUs in Argentina. Infect Control Hosp Epidemiol 2018;39:445-451.


Asunto(s)
Bacteriemia , Infecciones Relacionadas con Catéteres , Catéteres Venosos Centrales/efectos adversos , Infección Hospitalaria , Control de Infecciones , Argentina/epidemiología , Bacteriemia/epidemiología , Bacteriemia/etiología , Bacteriemia/prevención & control , Infecciones Relacionadas con Catéteres/epidemiología , Infecciones Relacionadas con Catéteres/etiología , Infecciones Relacionadas con Catéteres/prevención & control , Infección Hospitalaria/epidemiología , Infección Hospitalaria/prevención & control , Humanos , Incidencia , Control de Infecciones/métodos , Control de Infecciones/organización & administración , Evaluación de Procesos y Resultados en Atención de Salud , Evaluación de Programas y Proyectos de Salud/estadística & datos numéricos , Factores de Riesgo
9.
Am J Infect Control ; 46(6): 674-679, 2018 06.
Artículo en Inglés | MEDLINE | ID: mdl-29329916

RESUMEN

BACKGROUND: To analyze the impact of the International Nosocomial Infection Control Consortium (INICC) multidimensional approach (IMA) on ventilator-associated pneumonia (VAP) rates in 11 hospitals within 5 cities of Argentina from January 2014-April 2017. METHODS: A multicenter, prospective, before-after surveillance study was conducted through the use of International Nosocomial Infection Control Consortium Surveillance Online System. During baseline, we performed outcome surveillance of VAP applying the definitions of the Centers for Disease Control andPrevention's National Healthcare Safety Network. During intervention, we implemented the IMA, which included a bundle of infection prevention practice interventions, education, outcome surveillance, process surveillance, feedback on VAP rates and consequences, and performance feedback of process surveillance. Bivariate and multivariate regression analyses were performed using a logistic regression model to estimate the effect of the intervention. RESULTS: We recorded 3,940 patients admitted to 14 intensive care units. At baseline, there were 19.9 VAPs per 1,000 mechanical ventilator (MV)-days-with 2,920 MV-days and 58 VAPs, which was reduced during intervention to 9.4 VAPs per 1,000 MV-days-with 9,261 MV-days and 103 VAPs. This accounted for a 52% rate reduction (incidence density rate, 0.48; 95% confidence interval, 0.3-0.7; P .001). CONCLUSIONS: Implementing the IMA was associated with significant reductions in VAP rates in intensive care units within Argentina.


Asunto(s)
Infección Hospitalaria/epidemiología , Infección Hospitalaria/prevención & control , Control de Infecciones/métodos , Unidades de Cuidados Intensivos , Neumonía Asociada al Ventilador/epidemiología , Neumonía Asociada al Ventilador/prevención & control , Adulto , Anciano , Anciano de 80 o más Años , Argentina/epidemiología , Ciudades/epidemiología , Femenino , Hospitales , Humanos , Incidencia , Masculino , Persona de Mediana Edad , Estudios Prospectivos
10.
Actual. SIDA. infectol ; 25(95): 22-26, 20170000. fig, tab
Artículo en Español | LILACS, BINACIS | ID: biblio-1531047

RESUMEN

El Programa Nacional de Inmunizaciones en Argentina es-tablece la administración universal y obligatoria de las vacunas doble adultos (dT) y hepatitis B (HB) y las vacunas antigripal y antineumocó-cica para poblaciones especiales y mayores de 65 años. Son gratuitas y, excepto las vacunas antigripal y antineumocócica en personas en-tre 2-64 años, no requieren prescripción para su administración. Sin embargo, las tasas de vacunación en los adultos son bajas. Mejorar las coberturas vacunales en adultos es un desafío. Realizamos un estu-dio prospectivo de corte transversal para evaluar la implementación de una estrategia de vacunación combinada para aumentar la vacunación de los adultos de una institución. Esta se basó en el requerimiento obli-gatorio de dT en las cirugías programadas junto con el consejo médico en el vacunatorio y el acceso inmediato a la vacunación. Como resulta-do de esta estrategia se administraron 2.946 dosis extra que represen-tan un aumento de 312 % sobre las dosis sin intervención. Esta estrate-gia simple podría ser replicada fácilmente en otros centros


The National Immunization Program in Argentina recom-mends tetanus and diphtheria vaccine [Td] and hepatitis B for all healthy adults and influenza and pneumococcal vaccines for special populations. Despite the fact that these vaccines are free and without requirement for prescription, rates of vaccination remain low in adults.Improving vaccina-tion coverage among adults remains a major challenge. We performed a prospective cross-sectional study to assess a combined vaccination strat-egy in order to enhance compliance in a single institution. It was based on institutional requirement of Td vaccine for all elective surgery plus med-ical counseling provided by a trained physician at the Vaccination Room and immediate access to vaccination. As a result of this strategy, 2946 extra doses of vaccines were given. These doses represent an increase of 312% from the doses estimated without our intervention. This simple strategy may be easily replicated in other centers


Asunto(s)
Humanos , Masculino , Femenino , Anciano , Anciano de 80 o más Años , Estudios Prospectivos , Inmunización/estadística & datos numéricos , Programas de Inmunización
11.
Actual. SIDA. infectol ; 25(95): 22-26, 20170000. tab, fig
Artículo en Español | LILACS, BINACIS | ID: biblio-1357513

RESUMEN

El Programa Nacional de Inmunizaciones en Argentina es-tablece la administración universal y obligatoria de las vacunas doble adultos (dT) y hepatitis B (HB) y las vacunas antigripal y antineumocó-cica para poblaciones especiales y mayores de 65 años. Son gratuitas y, excepto las vacunas antigripal y antineumocócica en personas en-tre 2-64 años, no requieren prescripción para su administración. Sin embargo, las tasas de vacunación en los adultos son bajas. Mejorar las coberturas vacunales en adultos es un desafío. Realizamos un estu-dio prospectivo de corte transversal para evaluar la implementación de una estrategia de vacunación combinada para aumentar la vacunación de los adultos de una institución. Esta se basó en el requerimiento obli-gatorio de dT en las cirugías programadas junto con el consejo médico en el vacunatorio y el acceso inmediato a la vacunación. Como resulta-do de esta estrategia se administraron 2.946 dosis extra que represen-tan un aumento de 312 % sobre las dosis sin intervención. Esta estrate-gia simple podría ser replicada fácilmente en otros centros


The National Immunization Program in Argentina recom-mends tetanus and diphtheria vaccine [Td] and hepatitis B for all healthy adults and influenza and pneumococcal vaccines for special populations. Despite the fact that these vaccines are free and without requirement for prescription, rates of vaccination remain low in adults.Improving vaccina-tion coverage among adults remains a major challenge. We performed a prospective cross-sectional study to assess a combined vaccination strat-egy in order to enhance compliance in a single institution. It was based on institutional requirement of Td vaccine for all elective surgery plus med-ical counseling provided by a trained physician at the Vaccination Room and immediate access to vaccination. As a result of this strategy, 2946 extra doses of vaccines were given. These doses represent an increase of 312% from the doses estimated without our intervention. This simple strategy may be easily replicated in other centers


Asunto(s)
Humanos , Estudios Transversales/estadística & datos numéricos , Estudios Prospectivos , Vacunación/estadística & datos numéricos , Programas de Inmunización , Cobertura de Vacunación
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