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1.
Cardiovasc Diabetol ; 23(1): 312, 2024 Aug 24.
Artículo en Inglés | MEDLINE | ID: mdl-39182080

RESUMEN

BACKGROUND: The triglyceride glucose (TyG) index, as a reliable marker of insulin resistance, is associated with the incidence and poor prognosis of various cardiovascular diseases. However, the relationship between the TyG index and clinical outcomes in patients with severe aortic stenosis (AS) who underwent transcatheter aortic valve replacement (TAVR) remains unclear. METHODS: This study consecutively enrolled 1569 patients with AS underwent TAVR at West China Hospital of Sichuan University between April 2014 and August 2023. The outcomes of interest included all-cause mortality, cardiovascular mortality, and major adverse cardiovascular events (MACE). Multivariate adjusted Cox regression and restricted cubic splines (RCS) regression analyses were used to assess the associations between the TyG index and the clinical outcomes. The incremental prognostic value of the TyG index was further assessed by the time-dependent Harrell's C-index, integrated discrimination improvement (IDI) and the net reclassification improvement (NRI). RESULTS: During a median follow-up of 1.09 years, there were 146, 70, and 196 patients experienced all-cause death, cardiovascular death, and MACE, respectively. After fully adjusting for confounders, a per-unit increase of TyG index was associated with a 441% (adjusted HR: 5.41, 95% CI: 4.01-7.32), 385% (adjusted HR: 4.85, 95% CI: 3.16-7.43), and 347% (adjusted HR: 4.47, 95% CI: 3.42-5.85) higher risk of all-cause mortality, cardiovascular mortality and MACE, respectively. The RCS regression analyses revealed a linear association between TyG index and endpoints (all P for non-linearity > 0.05) with 8.40 as the optimal binary cutoff point. Furthermore, adding TyG index to the basic risk model provided a significant incremental value in predicting poor prognosis (Time-dependent Harrell's C-index increased for all the endpoints; All-cause mortality, IDI: 0.11, P < 0.001; NRI: 0.32, P < 0.001; Cardiovascular mortality, IDI: 0.043, P < 0.001; NRI: 0.37, P < 0.001; MACE, IDI: 0.092, P < 0.001; NRI: 0.32, P < 0.001). CONCLUSIONS: In patients with severe AS receiving TAVR, there was a positive linear relationship between TyG index and poor prognosis, with 8.4 as the optimal bivariate cutoff value. Our findings suggest TyG index holds potential value for risk stratification and guiding therapeutic decisions in patients after TAVR.


Asunto(s)
Estenosis de la Válvula Aórtica , Biomarcadores , Glucemia , Valor Predictivo de las Pruebas , Índice de Severidad de la Enfermedad , Reemplazo de la Válvula Aórtica Transcatéter , Triglicéridos , Humanos , Estenosis de la Válvula Aórtica/cirugía , Estenosis de la Válvula Aórtica/sangre , Estenosis de la Válvula Aórtica/mortalidad , Estenosis de la Válvula Aórtica/diagnóstico , Reemplazo de la Válvula Aórtica Transcatéter/efectos adversos , Reemplazo de la Válvula Aórtica Transcatéter/mortalidad , Masculino , Femenino , Estudios Retrospectivos , Anciano , Medición de Riesgo , Factores de Riesgo , Anciano de 80 o más Años , Factores de Tiempo , Resultado del Tratamiento , China/epidemiología , Biomarcadores/sangre , Glucemia/metabolismo , Triglicéridos/sangre , Causas de Muerte , Resistencia a la Insulina
2.
Environ Sci Technol ; 58(17): 7270-7278, 2024 Apr 30.
Artículo en Inglés | MEDLINE | ID: mdl-38625742

RESUMEN

Lead poisoning is globally concerning, yet limited testing hinders effective interventions in most countries. We aimed to create annual maps of county-specific blood lead levels in China from 1980 to 2040 using a machine learning model. Blood lead data from China were sourced from 1180 surveys published between 1980 and 2022. Additionally, regional statistical figures for 15 natural and socioeconomic variables were obtained or estimated as predictors. A machine learning model, using the random forest algorithm and 2973 generated samples, was created to predict county-specific blood lead levels in China from 1980 to 2040. Geometric mean blood lead levels in children (i.e., age 14 and under) decreased significantly from 104.4 µg/L in 1993 to an anticipated 40.3 µg/L by 2040. The number exceeding 100 µg/L declined dramatically, yet South Central China remains a hotspot. Lead exposure is similar among different groups, but overall adults and adolescents (i.e., age over 14), females, and rural residents exhibit slightly lower exposure compared to that of children, males, and urban residents, respectively. Our predictions indicated that despite the general reduction, one-fourth of Chinese counties rebounded during 2015-2020. This slower decline might be due to emerging lead sources like smelting and coal combustion; however, the primary factor driving the decline should be the reduction of a persistent source, legacy gasoline-derived lead. Our approach innovatively maps lead exposure without comprehensive surveys.


Asunto(s)
Plomo , Aprendizaje Automático , Plomo/sangre , China , Humanos , Femenino , Masculino , Niño , Adolescente , Exposición a Riesgos Ambientales , Intoxicación por Plomo/epidemiología , Intoxicación por Plomo/sangre
3.
Environ Res ; 262(Pt 2): 119932, 2024 Sep 04.
Artículo en Inglés | MEDLINE | ID: mdl-39241855

RESUMEN

China's groundwater is facing a significant threat from nitrate pollution. Here we analyzed 2348 regional surveys of groundwater nitrate levels in China from 1990 to 2020, examining distribution, trends, and drivers. This study uncovers a concerning rise in nitrate pollution, with estimated median nitrate levels climbing from 3.84 mg/L in 1990 to 6.94 mg/L in 2020. A stark contrast is observed between regions: the northern areas have a median nitrate concentration of 8.54 mg/L, significantly higher than the southern regions, where the median is just 7.15 mg/L. From 1990 to 2020, agricultural activity consistently emerges as the dominant driver of changes in groundwater nitrate concentrations, while groundwater exploitation, domestic pollution, and industrial production also contribute to varying degrees. This analysis highlights the urgency for region-specific policies and interventions to address the escalating nitrate pollution in China's groundwater.

4.
Environ Res ; 251(Pt 1): 118618, 2024 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-38442819

RESUMEN

Despite the significant threat of cadmium exposure in China, a national-level assessment has been conspicuously absent. This study bridges this critical gap by collecting, geospatial analyzing and multivariable regression analyzing published studies on urinary cadmium levels in Chinese from 1982 to 2021. Our research reveals a notable decline trend in cadmium exposure among Chinese populations. However, this trend varies by region, age and gender group, higher levels are seen in the South (1.04 µg/g cr) compared to the North (0.48 µg/g cr), and in adults (1.08 µg/g cr) relative to children (0.33 µg/g cr), with higher levels being more pronounced in females (6.17 µg/g cr). Urinary cadmium is significantly correlated with rice consumption (P < 0.001), while mining activities have been identified as the dominant factor for cadmium exposure in most regions of China, a trend that is evident both in past decades and is expected to continue into the next decade. These findings underscore the need for region-specific environmental and public health strategies, designed to effectively address the distinct cadmium exposure risks in various regions and among different population groups, thus enhancing protection against the adverse effects of cadmium.


Asunto(s)
Cadmio , Exposición a Riesgos Ambientales , Cadmio/orina , Cadmio/análisis , China , Humanos , Femenino , Masculino , Niño , Exposición a Riesgos Ambientales/análisis , Contaminantes Ambientales/orina , Contaminantes Ambientales/análisis , Adulto , Preescolar , Adolescente , Adulto Joven , Persona de Mediana Edad , Lactante , Monitoreo del Ambiente
5.
J Environ Manage ; 368: 122268, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-39178791

RESUMEN

China is facing a serious threat PAHs contaminated soil. To better understand the current state of soil PAH pollution in China and contribute to the development of feasible prevention and control measures and policies in the future. This study examines the spatiotemporal distributions of soil Polycyclic Aromatic Hydrocarbons (PAHs) pollution in China since 2000, and investigates the key factors influencing changes in levels of soil PAHs. The results of the survey on soil PAHs concentration levels in 716 areas were analyzed by visualization of ArcGIS pro data, correlation analysis and linear regression analysis, it was found that the increase in soil PAH pollution in China is concerning. The analysis indicates significant regional disparities, with pollution levels in the north being higher than in the south. Over the 20-year period, the median level of PAHs in soil increased by 476.8 µg/kg. Construction land areas that heavily rely on fossil fuels and industrial activities exhibit significantly higher concentrations of polycyclic aromatic hydrocarbons (PAHs) compared to other land use types. The study identifies key socio-economic factors linked to rising PAH levels, including energy consumption (notably coal and oil), industrial and domestic waste production. Coal consumption is highlighted as the leading factor in PAH concentration changes in 18 provinces, followed by industrial waste in 6 provinces. Future projections up to 2030 suggest continued influence of these factors on soil PAH levels. The research emphasizes the urgent necessity for comprehensive soil management policies to address the growing PAH pollution, offering insights into its dynamics and contributing factors in China.


Asunto(s)
Monitoreo del Ambiente , Hidrocarburos Policíclicos Aromáticos , Contaminantes del Suelo , Suelo , Hidrocarburos Policíclicos Aromáticos/análisis , Contaminantes del Suelo/análisis , China , Suelo/química
6.
J Sci Food Agric ; 103(14): 6826-6836, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-37278398

RESUMEN

BACKGROUND: Fermentation is known to enhance the nutritional profile and confer unique flavors to products. However, the resultant effects on stability and physicochemical properties remain unexplored. RESULTS: This study aims to elucidate the influence of fermentation on the stability and organoleptic characteristics of a rice protein beverage stabilized by carboxymethyl cellulose (CMC). The findings revealed that the average aggregate size escalated from 507 to 870 nm, concurrently exhibiting a significant increase in surface potential. The aggregation enhancement was substantiated by evident morphological changes and confocal laser scanning microscopical (CLSM) observations. A negative correlation was discerned between the physical stability of the beverage and fermentation duration. Moreover, flavor analysis of the beverage post a 3 h fermentation period highlighted an increase in aromatic ester compounds, thereby intensifying the aroma. CONCLUSION: The study corroborates that fermentation can detrimentally influence product stability while concurrently improving its flavor profile. By establishing a mix ratio of 10:1 for rice protein and CMC and forming a relatively stable system through electrostatic interaction at a pH of 5.4, a flavorful rice protein beverage can be derived post 3 h-fermentation process. These findings offer insights into the impact of varying fermentation durations on the stability and flavor of polysaccharide-based rice protein beverages. © 2023 Society of Chemical Industry.


Asunto(s)
Lactobacillus plantarum , Oryza , Lactobacillus plantarum/metabolismo , Fermentación , Carboximetilcelulosa de Sodio , Oryza/química , Bebidas/análisis
7.
Ecotoxicol Environ Saf ; 242: 113874, 2022 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-35843107

RESUMEN

Traditional soil vapor intrusion (VI) models usually rely on preset conceptual scenarios, simplifying the influences of limiting environmental covariates in determining indoor attenuation factors relative to subsurface sources. This study proposed a technical framework and applied it to predict VI attenuation factors based on site-specific parameters recorded in the United States Environmental Protection Agency (USEPA)'s and the California Environmental Protection Agency (CalEPA)'s VI databases, which can overcome the limitations of traditional VI models. We examined the databases with multivariate analysis of variance to identify effective covariates, which were then employed to develop VI models with three machine learning algorithms. The results of multivariate analysis show that the effective covariates include soil texture, source depth, foundation type, lateral separation, surface cover, and land use. Based on these covariates, the predicted attenuation factors by these new models are generally within one order of magnitude of the observations recorded in the databases. Then the developed models were employed to generate the generic indoor attenuation factors to subsurface vapor (i.e., the 95th percentile of selected dataset), the values of which are different between the USEPA's and CalEPA's databases by one order of magnitude, although comparable to recommendations by the USEPA and literature, respectively. Such a difference may reflect the significant regional disparity in factors such as building structures or operational conditions (e.g., indoor air exchange rates), which necessitates generating generic VI attenuation factors on a state-specific basis. This study provides an alternative for VI risk screens on a site-specific basis, especially in states with a good collection of datasets. Although the proposed technical framework is used for the VI databases, it can be equally applied to other environmental science problems.


Asunto(s)
Contaminación del Aire Interior , Contaminación del Aire Interior/análisis , Gases , Aprendizaje Automático , Análisis Multivariante , Suelo/química , Estados Unidos , Volatilización
8.
J Therm Spray Technol ; 31(1-2): 46-58, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-37520911

RESUMEN

In thermal spray process, the characteristics of in-flight particles (velocity and temperature) play an important role regarding the microstructure of the deposit and thus the coating performances. The implementation of diagnostic devices is necessary to measure such characteristics. Many imaging systems and algorithms have been developed for identifying and tracking in-flight particles. However, these current image systems have significant limitations in terms of accuracy for example. One key to solving the tracking problem is to get an algorithm that can effectively distinguish different particles in the same image frame at the same time. This study aims to develop an algorithm capable of identifying a large number of in-flight particles sprayed by thermal process. The results show that the noise and vignettes could be successfully treated, particles are clearly recognized in the background, leading to properly measuring the sizes and positions of the particle versus time. The proposed algorithm has a higher recognition rate and recognition range than other algorithms, which will provide a reasonable basis for subsequent calculation and processing.

9.
Herz ; 46(Suppl 1): 1-8, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-31807789

RESUMEN

BACKGROUND: Since readmission rate is an important clinical index to determine the quality of inpatient care and hospital performance, the aim of this study was to explain the causes and predictors of readmission following transcatheter aortic valve implantation (TAVI) at short-term and mid-term follow-up. METHODS AND RESULTS: A systematic review and meta-analysis of all published articles from Embase, Pubmed/MEDLINE, and Ovid was carried out. In all, 10 studies including 52,702 patients were identified. The pooled estimate for the overall event rate was 0.15, and cardiovascular causes were the main reason for 30-day readmission (0.42, 95% confidence interval [CI]: 0.39-0.45). In addition, the pooled incidence of 1­year readmission was 0.31, and cardiovascular events were still the main cause (0.41, 95% CI: 0.33-0.48). Patients with major and life-threatening bleeding, new permanent pacemaker implantation, and clinical heart failure were associated with a high risk for early readmission after TAVI. Moreover, an advanced (≥3) New York Heart Association classification, acute kidney injury, paravalvular leak, mitral regurgitation (≥ moderate), and major bleeding predicted unfavorable outcome to 1­year readmission. Female gender and transfemoral TAVI was associated with a lower risk for unplanned rehospitalization. CONCLUSIONS: This meta-analysis found cardiovascular factors to be the main causes for both 30-day and 1­year rehospitalization. Heart failure represented the most common cardiovascular event at both short-term and mid-term follow-up. Several baseline characteristics and procedure-related factors were deemed unfavorable predictors of readmission. Importantly, transfemoral access and female gender were associated with a lower risk of readmission.


Asunto(s)
Estenosis de la Válvula Aórtica , Prótesis Valvulares Cardíacas , Insuficiencia de la Válvula Mitral , Reemplazo de la Válvula Aórtica Transcatéter , Válvula Aórtica , Estenosis de la Válvula Aórtica/cirugía , Femenino , Humanos , Readmisión del Paciente , Complicaciones Posoperatorias/epidemiología , Factores de Riesgo , Reemplazo de la Válvula Aórtica Transcatéter/efectos adversos , Resultado del Tratamiento
10.
Artículo en Inglés | MEDLINE | ID: mdl-32085900

RESUMEN

Microtubules are made up of tubulin protein and play a very important part in numerous cellular events of eukaryotic cells, which is why they are seen as attractive targets for tumor chemotherapy. BNC105, a known vascular targeting agent, has entered in phase II clinical trials. It has previously been confirmed that BNC105 is an effective microtubule targeting agent for various cancers. BNC105 exhibits selectivity for tumor cells, elicits vascular disrupting effects, and inhibits tumor growth. However, the molecular mechanism of BNC105 is still elusive. Herein, the crystal structure of BNC105 in complex with tubulin protein is revealed, demonstrating the its interaction with the colchicine binding site. In order to thoroughly evaluate its molecular mechanism from a structural-activity-relationship standpoint, the binding mode of tubulin to BNC-105 is compared with colchicine, CA-4 and other BNC-105 derivatives. Our study not only confirms the detailed interactions of the BNC105-tubulin complex, but also offer substantial structural foundation for the design and development of novel benzo[b]furan derivatives as microtubule targeting agents.

11.
J Environ Qual ; 47(5): 1179-1185, 2018 09.
Artículo en Inglés | MEDLINE | ID: mdl-30272787

RESUMEN

In this work we investigate the role of soil texture in petroleum vapor intrusion (PVI) by performing numerical modeling, analytical calculations, and statistical analysis of the USEPA's PVI database. Numerical simulations were conducted for three kinds of soil (sand, sandy loam, and clay), and the results indicate that the maximum attenuations of vapor concentrations from source to indoor air were observed when the clay soil is below the building. In the anaerobic zone, the normalized soil gas concentration profiles were observed to be similar and independent of soil type, whereas in the aerobic zone, a more significant attenuation was observed in finer grained soils. Such a finding is consistent with the statistical results of the USEPA's PVI database, which indicate that in the near-source zone, the soil gas concentration in coarse-grained soil tends to be lower than that in fine-grained soil, possibly caused by a weaker source due to mass loss by volatilization, whereas at a distance away from the source, the measured soil gas concentrations in fine-grained soils become much lower because of aerobic biodegradation with a shorter diffusive reaction length. Thus, 3 and 5 m are proposed as soil-type-dependent vertical screening distances for fine and coarse-grained soils, respectively. It should be noted that the validity of these screening distances is examined only for relatively homogeneous soils, and they may not be applicable for cases involving layered soil systems, where the availability of O in the subfoundation should be evaluated with subslab or multidepth samples to confirm the presence of aerobic biodegradation.


Asunto(s)
Modelos Químicos , Petróleo/análisis , Contaminantes del Suelo/química , Suelo/química , Volatilización
12.
Ground Water Monit Remediat ; 38(2): 79-89, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30524180

RESUMEN

A value of 0.001 is recommended by the United States Environmental Protection Agency (USEPA) for its groundwater-to-indoor air Generic Attenuation Factor (GAFG), used in assessing potential vapor intrusion (VI) impacts to indoor air, given measured groundwater concentrations of volatile chemicals of concern (e.g., chlorinated solvents). The GAFG can, in turn, be used for developing groundwater screening levels for VI given target indoor air quality screening levels. In this study, we examine the validity and applicability of the GAFG both for predicting indoor air impacts and for determining groundwater screening levels. This is done using both analysis of published data and screening model calculations. Among the 774 total paired groundwater-indoor air measurements in the USEPA's VI database (which were used by that agency to generate the GAFG) we found that there are 427 pairs for which a single groundwater measurement or interpolated value was applied to multiple buildings. In one case, up to 73 buildings were associated with a single interpolated groundwater value and in another case up to 15 buildings were associated with a single groundwater measurement (i.e, that the indoor air contaminant concentrations in all of the associated buildings were influenced by the concentration determined at a single point). In more than 70% of the cases (390 of 536 paired measurements in which horizontal building-monitoring well distance was recorded) the monitoring wells were located more than 30 meters (and some up to over 200 meters) from the associated buildings. In a few cases, the measurements in the database even improbably implied that soil gas contaminant concentrations increased, rather than decreased, in an upward direction from a contaminant source to a foundation slab. Such observations indicate problematic source characterization within the dataset used to generate the GAFG, and some indicate the possibility of a significant influence of a preferential contaminant pathway. While the inherent value of the USEPA database itself is not being questioned here, the above facts raise the very real possibility that the recommended groundwater attenuation factors are being influenced by variables or conditions that have not thus far been fully accounted for. In addition, the predicted groundwater attenuation factors often fall far beyond the upper limits of predictions from mathematical models of VI, ranging from screening models to detailed computational fluid dynamic models. All these models are based on the same fundamental conceptual site model, involving a vadose zone vapor transport pathway starting at an underlying uniform groundwater source and leading to the foundation of a building of concern. According to the analysis presented here, we believe that for scenarios for which such a "traditional" VI pathway is appropriate, 10-4 is a more appropriately conservative generic groundwater to indoor air attenuation factor than is the EPA-recommended 10-3. This is based both on the statistical analysis of USEPA's VI database, as well as the traditional mathematical models of VI. This result has been validated by comparison with results from some well documented field studies.

14.
J Environ Qual ; 46(4): 776-784, 2017 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-28783798

RESUMEN

Soil texture is believed to play a significant role in the migration of subsurface volatile chemicals into buildings at contaminated sites, an exposure process known as vapor intrusion (VI). In this study, we investigated the role of soil texture in determining the attenuation of contaminant soil gas concentration from groundwater source to receptor building. We performed soil column experiments, numerical simulations, and statistical analysis of the USEPA's VI database. The soil column experiments were conducted with commercial sand and soils with sand and sandy loam textures. Measured one-dimensional soil gas concentration profiles were compared with numerical predictions. Good agreement between experiments and model results supports the use of the classical multiphase chemical transport equation for simulating contaminant vapor transport from groundwater through the vadose zone. A full three-dimensional numerical model was then used to simulate typical VI scenarios with groundwater sources. Results indicate that, although soil particle texture can play a role in determining subslab-to-indoor air concentration attenuation, there is no obvious relationship between soil particle size and groundwater source-to-subslab except in the case of a shallow contaminant source. This conclusion is consistent with results reported in USEPA's VI database, in which variation in soil particle size does not affect source-to-subslab attenuation factors but does influence subslab-to-indoor air concentration attenuation factors by an average of about 0.4 order of magnitude. This finding suggests that an appropriate focus of VI site investigation should include the shallow soil beneath the building foundation.


Asunto(s)
Agua Subterránea , Contaminantes del Suelo/química , Gases , Suelo/química , Volatilización
15.
J Environ Qual ; 46(6): 1424-1433, 2017 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-29293853

RESUMEN

Preferential pathways can be significant vapor intrusion (VI) contributors, causing potentially higher inhalation risk to residents of affected buildings than that arising through traditional intrusion pathways. To assess land drains as a preferential pathway, a three-dimensional model, validated using data from a 4-yr field study, was used to study the roles of subfoundation soil permeability on soil gas flow and indoor depressurization. Results indicated that it is almost impossible for an indirect preferential pathway like a land drain ending in subfoundation soils with a permeability <10 m to affect indoor air quality if the land drain connects to a source with the same vapor concentration as that of the groundwater source beneath the building. An equation was developed to estimate the threshold permeability. We also found that even after the preferential pathway was identified using indoor depressurization (also known as controlled pressure method [CPM]) and then turned off, the influence of the preferential pathway and indoor depressurization on indoor concentration might last for months, although it may not be significant (i.e., may not exceed one order of magnitude, in this study). In the absence of such a preferential VI pathway, CPM may actually reduce indoor air concentrations of contaminants below those present under natural indoor pressure conditions, due to the emission rate limit determined by the upward diffusion rate from the vapor source. Our study highlights the role of measuring subfoundation soil permeability to soil gas flow in site investigations and warns practitioners about the possible mischaracterization of indoor air concentration after applying CPM in the absence of a preferential pathway.


Asunto(s)
Contaminación del Aire Interior/análisis , Gases/análisis , Agua Subterránea , Suelo/química
16.
Water Resour Res ; 53(5): 4499-4513, 2017 05.
Artículo en Inglés | MEDLINE | ID: mdl-29081548

RESUMEN

In this work, we present an analytical chlorinated vapor intrusion (CVI) model that can estimate source-to-indoor air concentration attenuation by simulating two-dimensional (2-D) vapor concentration profile in vertically heterogeneous soils overlying a homogenous vapor source. The analytical solution describing the 2-D soil gas transport was obtained by applying a modified Schwarz-Christoffel mapping method. A partial field validation showed that the developed model provides results (especially in terms of indoor emission rates) in line with the measured data from a case involving a building overlying a layered soil. In further testing, it was found that the new analytical model can very closely replicate the results of three-dimensional (3-D) numerical models at steady state in scenarios involving layered soils overlying homogenous groundwater sources. By contrast, by adopting a two-layer approach (capillary fringe and vadose zone) as employed in the EPA implementation of the Johnson and Ettinger model, the spatially and temporally averaged indoor concentrations in the case of groundwater sources can be higher than the ones estimated by the numerical model up to two orders of magnitude. In short, the model proposed in this work can represent an easy-to-use tool that can simulate the subsurface soil gas concentration in layered soils overlying a homogenous vapor source while keeping the simplicity of an analytical approach that requires much less computational effort.

17.
Water Resour Res ; 52(2): 1528-1539, 2016 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-28255184

RESUMEN

In this study we present an analytical solution of a two-dimensional petroleum vapor intrusion model, which incorporates a steady-state diffusion-dominated vapor transport in a homogeneous soil and piecewise first-order aerobic biodegradation limited by oxygen availability. This new model can help practitioners to easily generate two-dimensional soil gas concentration profiles for both hydrocarbons and oxygen and estimate hydrocarbon indoor air concentrations as a function of site-specific conditions such as source strength and depth, reaction rate constant, soil characteristics and building features. The soil gas concentration profiles generated by this new model are shown in good agreement with three-dimensional numerical simulations and two-dimensional measured soil gas data from a field study. This implies that for cases involving diffusion dominated soil gas transport, steady state conditions and homogenous source and soil, this analytical model can be used as a fast and easy-to-use risk screening tool by replicating the results of 3-D numerical simulations but with much less computational effort.

18.
Ground Water Monit Remediat ; 36(2): 94-100, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-28163564

RESUMEN

In this study we present a petroleum vapor intrusion tool implemented in Microsoft® Excel® using Visual Basic for Applications (VBA) and integrated within a graphical interface. The latter helps users easily visualize two-dimensional soil gas concentration profiles and indoor concentrations as a function of site-specific conditions such as source strength and depth, biodegradation reaction rate constant, soil characteristics and building features. This tool is based on a two-dimensional explicit analytical model that combines steady-state diffusion-dominated vapor transport in a homogeneous soil with a piecewise first-order aerobic biodegradation model, in which rate is limited by oxygen availability. As recommended in the recently released United States Environmental Protection Agency's final Petroleum Vapor Intrusion guidance, a sensitivity analysis and a simplified Monte Carlo uncertainty analysis are also included in the spreadsheet.

19.
Environ Sci Technol ; 49(19): 11577-85, 2015 Oct 06.
Artículo en Inglés | MEDLINE | ID: mdl-26322369

RESUMEN

At petroleum vapor intrusion (PVI) sites at which there is significant methane generation, upward advective soil gas transport may be observed. To evaluate the health and explosion risks that may exist under such scenarios, a one-dimensional analytical model describing these processes is introduced in this study. This new model accounts for both advective and diffusive transport in soil gas and couples this with a piecewise first-order aerobic biodegradation model, limited by oxygen availability. The predicted results from the new model are shown to be in good agreement with the simulation results obtained from a three-dimensional numerical model. These results suggest that this analytical model is suitable for describing cases involving open ground surface beyond the foundation edge, serving as the primary oxygen source. This new analytical model indicates that the major contribution of upward advection to indoor air concentration could be limited to the increase of soil gas entry rate, since the oxygen in soil might already be depleted owing to the associated high methane source vapor concentration.


Asunto(s)
Contaminación del Aire Interior/análisis , Metano/análisis , Modelos Teóricos , Petróleo , Medición de Riesgo/métodos , Suelo/química , Aire , Contaminación del Aire Interior/efectos adversos , Biodegradación Ambiental , Simulación por Computador , Explosiones , Gases/análisis , Vivienda , Humanos , Metano/química , Metano/metabolismo , Oxígeno/análisis , Oxígeno/metabolismo , Petróleo/análisis , Contaminantes del Suelo/análisis , Contaminantes del Suelo/química , Compuestos Orgánicos Volátiles/análisis , Compuestos Orgánicos Volátiles/química
20.
Food Chem ; 459: 140280, 2024 Nov 30.
Artículo en Inglés | MEDLINE | ID: mdl-38991445

RESUMEN

This study aims to investigate the influence of alkaline treatment duration (0-5 h) on the physicochemical properties and emulsifying performance of rapeseed protein during pH-shift process. Results showed that a 4-h alkaline treatment significantly reduced the particle size of rapeseed protein and led to a notable decrease in disulfide bond content, as well as alterations in subunit composition. Moreover, solubility of rapeseed protein increased from 18.10 ± 0.13% to 40.44 ± 1.74% post-treatment, accompanied by a âˆ¼ 40% enhancement in emulsifying properties. Morphological analysis revealed superior plasticity and sharper contours in 4-h alkali-treated rapeseed protein emulsions compared to untreated counterparts. Rheological analysis indicated higher viscosity and elasticity in the alkali-treated group. Overall, 4-h alkaline treatment markedly enhanced the multifaceted functional attributes of rapeseed protein during pH-shift process, rendering it a promising emulsifier in the food industry.


Asunto(s)
Brassica rapa , Emulsionantes , Emulsiones , Tamaño de la Partícula , Proteínas de Plantas , Reología , Solubilidad , Concentración de Iones de Hidrógeno , Proteínas de Plantas/química , Emulsiones/química , Emulsionantes/química , Brassica rapa/química , Viscosidad , Manipulación de Alimentos , Álcalis/química
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