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1.
Artículo en Inglés | MEDLINE | ID: mdl-29230312

RESUMEN

Internet and mobile technologies offer potentially critical ways of delivering mental health support in low-resource settings. Much evidence indicates an enormous negative impact of mental health problems in low- and middle-income countries (LMICs), and many of these problems are caused, or worsened, by exposure to wars, conflicts, natural and human-caused disasters, and other traumatic events. Though specific mental health treatments have been found to be efficacious and cost-effective for low-resource settings, most individuals living in these areas do not have access to them. Low-intensity task-sharing interventions will help, but there is a limit to the scalability and sustainability of human resources in these settings. To address the needs of trauma survivors, it will be important to develop and implement Internet and mobile technology resources to help reduce the scarcity, inequity, and inefficiency of current mental health services in LMICs. Mobile and Internet resources are experiencing a rapid growth in LMICs and can help address time, stigma, and cost barriers and connect those who have been socially isolated by traumatic events. This review discusses current research in technological interventions in low-resource settings and outlines key issues and future challenges and opportunities. Though formidable challenges exist for large-scale deployment of mobile and Internet mental health technologies, work to date indicates that these technologies are indeed feasible to develop, evaluate, and deliver to those in need of mental health services, and that they can be effective.

2.
J Environ Radioact ; 171: 226-233, 2017 May.
Artículo en Inglés | MEDLINE | ID: mdl-28286302

RESUMEN

Among the key environmental factors influencing the fate and transport of radionuclides in the environment is natural organic matter (NOM). While this has been known for decades, there still remains great uncertainty in predicting NOM-radionuclide interactions because of lack of understanding of radionuclide interactions with the specific organic moieties within NOM. Furthermore, radionuclide-NOM studies conducted using modelled organic compounds or elevated radionuclide concentrations provide compromised information related to true environmental conditions. Thus, sensitive techniques are required not only for the detection of radionuclides, and their different species, at ambient and/or far-field concentrations, but also for potential trace organic compounds that are chemically binding these radionuclides. GC-MS and AMS techniques developed in our lab are reviewed here that aim to assess how two radionuclides, iodine and plutonium, form strong bonds with NOM by entirely different mechanisms; iodine tends to bind to aromatic functionalities, whereas plutonium binds to N-containing hydroxamate siderophores at ambient concentrations. While low-level measurements are a prerequisite for assessing iodine and plutonium migration at nuclear waste sites and as environmental tracers, it is necessary to determine their in-situ speciation, which ultimately controls their mobility and transport in natural environments. More importantly, advanced molecular-level instrumentation (e.g., nuclear magnetic resonance (NMR) and Fourier-transform ion cyclotron resonance coupled with electrospray ionization (ESI-FTICRMS) were applied to resolve either directly or indirectly the molecular environments in which the radionuclides are associated with the NOM.


Asunto(s)
Radioisótopos de Yodo/análisis , Plutonio/análisis , Monitoreo de Radiación/métodos , Contaminantes Radiactivos/análisis , Modelos Químicos , Compuestos Orgánicos/química , Suelo/química
3.
Microb Biotechnol ; 6(5): 515-25, 2013 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-23331993

RESUMEN

To assess the applicability of latex cell coatings as an 'off-the-shelf' biocatalyst, the effect of osmoprotectants, temperature, humidity and O2 on preservation of H2 production in Rhodopseudomonas palustris coatings was evaluated. Immediately following latex coating coalescence (24 h) and for up to 2 weeks of dry storage, rehydrated coatings containing different osmoprotectants displayed similar rates of H2 production. Beyond 2 weeks of storage, sorbitol-treated coatings lost all H2 production activity, whereas considerable H2 production was still detected in sucrose- and trehalose-stabilized coatings. The relative humidity level at which the coatings were stored had a significant impact on the recovery and subsequent rates of H2 production. After 4 weeks storage under air at 60% humidity, coatings produced only trace amounts of H2 (0-0.1% headspace accumulation), whereas those stored at < 5% humidity retained 27-53% of their H2 production activity after 8 weeks of storage. When stored in argon at < 5% humidity and room temperature, R. palustris coatings retained full H2 production activity for 3 months, implicating oxidative damage as a key factor limiting coating storage. Overall, the results demonstrate that biocatalytic latex coatings are an attractive cell immobilization platform for preservation of bioactivity in the dry state.


Asunto(s)
Reactores Biológicos/microbiología , Biotecnología/métodos , Células Inmovilizadas/metabolismo , Hidrógeno/metabolismo , Rhodopseudomonas/metabolismo , Desecación , Látex , Rhodopseudomonas/efectos de los fármacos , Rhodopseudomonas/efectos de la radiación , Temperatura
4.
Environ Sci Technol ; 45(13): 5543-9, 2011 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-21663237

RESUMEN

Iodine occurs in multiple oxidation states in aquatic systems in the form of organic and inorganic species. This feature leads to complex biogeochemical cycling of stable iodine and its long-lived isotope, (129)I. In this study, we investigated the sorption, transport, and interconversion of iodine species by comparing their mobility in groundwaters at ambient concentrations of iodine species (10(-8) to 10(-7) M) to those at artificially elevated concentrations (78.7 µM), which often are used in laboratory analyses. Results demonstrate that the mobility of iodine species greatly depends on, in addition to the type of species, the iodine concentration used, presumably limited by the number of surface organic carbon binding sites to form covalent bonds. At ambient concentrations, iodide and iodate were significantly retarded (K(d) values as high as 49 mL g(-1)), whereas at concentrations of 78.7 µM, iodide traveled along with the water without retardation. Appreciable amounts of iodide during transport were retained in soils due to iodination of organic carbon, specifically retained by aromatic carbon. At high input concentration of iodate (78.7 µM), iodate was found to be reduced to iodide and subsequently followed the transport behavior of iodide. These experiments underscore the importance of studying iodine geochemistry at ambient concentrations and demonstrate the dynamic nature of their speciation during transport conditions.


Asunto(s)
Sedimentos Geológicos/química , Radioisótopos de Yodo/análisis , Yodo/análisis , Ríos , Adsorción , Sitios de Unión , Transporte Biológico , Carbono/metabolismo , Georgia , Movimientos del Agua
5.
Environ Sci Technol ; 44(23): 9042-8, 2010 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-21069952

RESUMEN

In aquatic environments, iodine mainly exists as iodide, iodate, and organic iodine. The high mobility of iodine in aquatic systems has led to (129)I contamination problems at sites where nuclear fuel has been reprocessed, such as the F-area of Savannah River Site. In order to assess the distribution of (129)I and stable (127)I in environmental systems, a sensitive and rapid method was developed which enables determination of isotopic ratios of speciated iodine. Iodide concentrations were quantified using gas chromatography-mass spectrometry (GC-MS) after derivatization to 4-iodo-N,N-dimethylaniline. Iodate concentrations were quantified by measuring the difference of iodide concentrations in the solution before and after reduction by Na(2)S(2)O(5). Total iodine, including inorganic and organic iodine, was determined after conversion to iodate by combustion at 900 °C. Organo-iodine was calculated as the difference between the total iodine and total inorganic iodine (iodide and iodate). The detection limits of iodide-127 and iodate-127 were 0.34 nM and 1.11 nM, respectively, whereas the detection limits for both iodide-129 and iodate-129 was 0.08 nM (i.e., 2pCi (129)I/L). This method was successfully applied to water samples from the contaminated Savannah River Site, South Carolina, and more pristine Galveston Bay, Texas.


Asunto(s)
Monitoreo del Ambiente/métodos , Cromatografía de Gases y Espectrometría de Masas , Yodatos/análisis , Yoduros/análisis , Contaminantes Químicos del Agua/análisis , Agua Dulce/química , Hidrocarburos Yodados/análisis , Isótopos de Yodo/análisis , Radioisótopos de Yodo/análisis , Compuestos Orgánicos , Suelo/química , Contaminantes del Suelo/análisis , Tiroxina/análisis , Contaminantes Radiactivos del Agua/análisis
6.
Environ Sci Technol ; 43(19): 7258-64, 2009 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-19848131

RESUMEN

One of the key risk drivers at radioactive waste disposal facilities is radioiodine, especially 129I. As iodine mobility varies greatly with iodine speciation, experiments with 129I-contaminated aquifer sediments from the Savannah River Site located in Aiken, SC, were carried out to test iodine interactions with soils and aquifer sediments. Using tracer 125I- and stable 127I- additions, it was shown that such interactions were highly dependent on I- concentrations added to sediment suspensions, contact time with the sediment, and organic carbon (OC) content, resulting in an empirical particle-water partition coefficient (Kd) that was an inverse power function of the added I- concentration. However, Kd values of organically bound 127I were 3 orders of magnitude higher than those determined after 1-2 weeks of tracer equilibration, approaching those of OC. Under ambient conditions, organo-iodine (OI) was a major fraction (67%) of the total iodine in the dissolved phase and by implication of the particulate phase. As the total concentration of amended I- increased, the fraction of detectable dissolved OI decreased. This trend, attributed to OC becoming the limiting factor in the aquifer sediment explains why at elevated I-concentrations OI is often not detected.


Asunto(s)
Sedimentos Geológicos/química , Yodo/química , Suelo/análisis , Técnicas de Química Analítica , Monitoreo del Ambiente , Radioisótopos de Yodo/química , Cinética , Residuos Radiactivos , Ríos/química , Contaminantes del Suelo/química
7.
Appl Environ Microbiol ; 67(12): 5384-91, 2001 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-11722883

RESUMEN

A Tn5-based mutagenesis strategy was used to generate a collection of trichloroethylene (TCE)-sensitive (TCS) mutants in order to identify repair systems or protective mechanisms that shield Burkholderia cepacia G4 from the toxic effects associated with TCE oxidation. Single Tn5 insertion sites were mapped within open reading frames putatively encoding enzymes involved in DNA repair (UvrB, RuvB, RecA, and RecG) in 7 of the 11 TCS strains obtained (4 of the TCS strains had a single Tn5 insertion within a uvrB homolog). The data revealed that the uvrB-disrupted strains were exceptionally susceptible to killing by TCE oxidation, followed by the recA strain, while the ruvB and recG strains were just slightly more sensitive to TCE than the wild type. The uvrB and recA strains were also extremely sensitive to UV light and, to a lesser extent, to exposure to mitomycin C and H(2)O(2). The data from this study establishes that there is a link between DNA repair and the ability of B. cepacia G4 cells to survive following TCE transformation. A possible role for nucleotide excision repair and recombination repair activities in TCE-damaged cells is discussed.


Asunto(s)
Proteínas Bacterianas/metabolismo , Burkholderia cepacia/crecimiento & desarrollo , Burkholderia cepacia/genética , Reparación del ADN , Tricloroetileno/metabolismo , Proteínas Bacterianas/efectos de los fármacos , Proteínas Bacterianas/genética , Secuencia de Bases , Biodegradación Ambiental , Burkholderia cepacia/efectos de los fármacos , Burkholderia cepacia/efectos de la radiación , Elementos Transponibles de ADN , Datos de Secuencia Molecular , Mutagénesis Insercional , Oxidación-Reducción , Análisis de Secuencia de ADN , Tricloroetileno/farmacología , Rayos Ultravioleta
8.
Biodegradation ; 12(2): 81-103, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-11710592

RESUMEN

Cometabolism recognizes that microorganisms can transform non-growth-supporting substrates. The term "cometabolism" was first introduced over 30 years ago and has been redefined, criticized, and used widely ever since. In this review we have examined the aerobic cometabolism of chlorinated solvents, with a particular emphasis on the cometabolism of trichloroethylene. Monooxygenases or dioxygenases with relaxed substrate ranges initiate these transformations. The physiological role of the oxygenases is to initiate the metabolism of growth-supporting substrates (e.g., methane, propane, butane, toluene, ethylene, and ammonia). Diverse enzymes catalyze these oxidative reactions with chlorinated solvents. Synthesis of most of these enzymes is induced by the presence of the growth-supporting substrate and is largely regulated at the level of gene transcription. The genes that code for a given oxygenase are usually clustered together in a single operon and often share homology with counterparts that code for the subunits of related oxygenases in other bacteria. During cometabolism the growth-supporting and non-growth-supporting substrates can both bind to the oxygenase. Transformation of chlorinated solvents by these enzymes presents the cell with a new set of compounds. Some of these compounds are toxic to the cells, others are stable products that are expelled from the cell, and in a few cases the cells utilize the products. The combined effects of cometabolism can have a profound influence on a cell.


Asunto(s)
Bacterias/metabolismo , Enzimas/genética , Enzimas/metabolismo , Tricloroetileno/metabolismo , Aerobiosis , Biodegradación Ambiental , Regulación de la Expresión Génica , Ingeniería Genética , Oxigenasas de Función Mixta/metabolismo , Oxidorreductasas/metabolismo , Oxigenasas/química , Oxigenasas/metabolismo , Solventes/metabolismo
9.
Appl Environ Microbiol ; 67(11): 4992-8, 2001 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-11679317

RESUMEN

Alkane monooxygenases in Nocardioides sp. strain CF8 were examined at the physiological and genetic levels. Strain CF8 can utilize alkanes ranging in chain length from C(2) to C(16). Butane degradation by butane-grown cells was strongly inhibited by allylthiourea, a copper-selective chelator, while hexane-, octane-, and decane-grown cells showed detectable butane degradation activity in the presence of allylthiourea. Growth on butane and hexane was strongly inhibited by 1-hexyne, while 1-hexyne did not affect growth on octane or decane. A specific 30-kDa acetylene-binding polypeptide was observed for butane-, hexane-, octane-, and decane-grown cells but was absent from cells grown with octane or decane in the presence of 1-hexyne. These results suggest the presence of two monooxygenases in strain CF8. Degenerate primers designed for PCR amplification of genes related to the binuclear-iron-containing alkane hydroxylase from Pseudomonas oleovorans were used to clone a related gene from strain CF8. Reverse transcription-PCR and Northern blot analysis showed that this gene encoding a binuclear-iron-containing alkane hydroxylase was expressed in cells grown on alkanes above C(6). These results indicate the presence of two distinct monooxygenases for alkane oxidation in Nocardioides sp. strain CF8.


Asunto(s)
Actinomycetales/enzimología , Alcanos/metabolismo , Oxigenasas/química , Oxigenasas/metabolismo , Actinomycetales/genética , Actinomycetales/crecimiento & desarrollo , Secuencia de Aminoácidos , Biodegradación Ambiental , Northern Blotting , Butanos/metabolismo , Cobre/metabolismo , Medios de Cultivo , Citocromo P-450 CYP4A , Sistema Enzimático del Citocromo P-450/química , Sistema Enzimático del Citocromo P-450/genética , Sistema Enzimático del Citocromo P-450/metabolismo , Hierro/metabolismo , Oxigenasas de Función Mixta/química , Oxigenasas de Función Mixta/genética , Oxigenasas de Función Mixta/metabolismo , Datos de Secuencia Molecular , Oxidación-Reducción , Oxigenasas/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Análisis de Secuencia de ADN
10.
Appl Environ Microbiol ; 67(5): 2107-15, 2001 May.
Artículo en Inglés | MEDLINE | ID: mdl-11319088

RESUMEN

The effects of trichloroethylene (TCE) oxidation on toluene 2-monooxygenase activity, general respiratory activity, and cell culturability were examined in the toluene-oxidizing bacterium Burkholderia cepacia G4. Nonspecific damage outpaced inactivation of toluene 2-monooxygenase in B. cepacia G4 cells. Cells that had degraded approximately 0.5 micromol of TCE (mg of cells(-1)) lost 95% of their acetate-dependent O(2) uptake activity (a measure of general respiratory activity), yet toluene-dependent O(2) uptake activity decreased only 35%. Cell culturability also decreased upon TCE oxidation; however, the extent of loss varied greatly (up to 3 orders of magnitude) with the method of assessment. Addition of catalase or sodium pyruvate to the surfaces of agar plates increased enumeration of TCE-injured cells by as much as 100-fold, indicating that the TCE-injured cells were ultrasensitive to oxidative stress. Cell suspensions that had oxidized TCE recovered the ability to grow in liquid minimal medium containing lactate or phenol, but recovery was delayed substantially when TCE degradation approached 0.5 micromol (mg of cells(-1)) or 66% of the cells' transformation capacity for TCE at the cell density utilized. Furthermore, among B. cepacia G4 cells isolated on Luria-Bertani agar plates from cultures that had degraded approximately 0.5 micromol of TCE (mg of cells(-1)), up to 90% were Tol(-) variants, no longer capable of TCE degradation. These results indicate that a toxicity threshold for TCE oxidation exists in B. cepacia G4 and that once a cell suspension has exceeded this toxicity threshold, the likelihood of reestablishing an active, TCE-degrading biomass from the cells will decrease significantly.


Asunto(s)
Burkholderia cepacia/crecimiento & desarrollo , Tricloroetileno/metabolismo , Tricloroetileno/toxicidad , Biodegradación Ambiental , Burkholderia cepacia/metabolismo , Medios de Cultivo , Oxigenasas de Función Mixta/antagonistas & inhibidores , Oxigenasas de Función Mixta/metabolismo , Oxidación-Reducción , Tolueno/metabolismo
11.
Patient Educ Couns ; 39(1): 49-59, 2000 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-11013547

RESUMEN

This study investigated the extent to which the individual orientations of physicians and patients and the congruence between them are associated with patient satisfaction. A survey was mailed to 400 physicians and 1020 of their patients. All respondents filled out the Patient-Practitioner Orientation Scale, which measures the roles that doctors and patients believe each should play in the course of their interaction. Patients also rated their satisfaction with their doctors. Among patients, we found that females and those who were younger, more educated, and healthier were significantly more patient-centered. However, none of these variables were significantly related to satisfaction. Among physicians, females were more patient-centered, and years in practice was related to satisfaction and orientation in a non-linear fashion. The congruence data indicated that patients were highly satisfied when their physicians either had a matching orientation or were more patient-centered. However, patients whose doctors were not as patient-centered were significantly less satisfied.


Asunto(s)
Actitud del Personal de Salud , Satisfacción en el Trabajo , Satisfacción del Paciente , Atención Dirigida al Paciente/normas , Relaciones Médico-Paciente , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad
12.
Appl Environ Microbiol ; 65(2): 632-9, 1999 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-9925593

RESUMEN

High concentrations of acetylene (10 to 50% [vol/vol] gas phase) were required to inhibit the growth of Burkholderia cepacia G4 on toluene, while 1% (vol/vol) (gas phase) propyne or 1-butyne completely inhibited growth. Low concentrations of longer-chain alkynes (C5 to C10) were also effective inhibitors of toluene-dependent growth, and 2- and 3-alkynes were more potent inhibitors than their 1-alkyne counterparts. Exposure of toluene-grown B. cepacia G4 to alkynes resulted in the irreversible loss of toluene- and o-cresol-dependent O2 uptake activities, while acetate- and 3-methylcatechol-dependent O2 uptake activities were unaffected. Toluene-dependent O2 uptake decreased upon the addition of 1-butyne in a concentration- and time-dependent manner. The loss of activity followed first-order kinetics, with apparent rate constants ranging from 0.25 min-1 to 2.45 min-1. Increasing concentrations of toluene afforded protection from the inhibitory effects of 1-butyne. Furthermore, oxygen, supplied as H2O2, was required for inhibition by 1-butyne. These results suggest that alkynes are specific, mechanism-based inactivators of toluene 2-monooxygenase in B. cepacia G4, although the simplest alkyne, acetylene, was relatively ineffective compared to longer alkynes. Alkene analogs of acetylene and propyne-ethylene and propylene-were not inactivators of toluene 2-monooxygenase activity in B. cepacia G4 but were oxidized to their respective epoxides, with apparent Ks and Vmax values of 39.7 microM and 112.3 nmol min-1 mg of protein-1 for ethylene and 32.3 microM and 89.2 nmol min-1 mg of protein-1 for propylene.


Asunto(s)
Alquinos/farmacología , Burkholderia cepacia/enzimología , Oxigenasas de Función Mixta/antagonistas & inhibidores , Tolueno/metabolismo , Alquenos/metabolismo , Burkholderia cepacia/efectos de los fármacos , Burkholderia cepacia/crecimiento & desarrollo , Activación Enzimática , Etilenos/metabolismo , Cinética , Oxigenasas de Función Mixta/metabolismo , Oxidación-Reducción
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