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1.
Environ Sci Technol ; 58(1): 280-290, 2024 Jan 09.
Artículo en Inglés | MEDLINE | ID: mdl-38153403

RESUMEN

While human mobility plays a crucial role in determining ambient air pollution exposures and health risks, research to date has assessed risks on the basis of almost solely residential location. Here, we leveraged a database of ∼128-144 million workers in the United States and published ambient PM2.5 data between 2011 and 2018 to explore how incorporating information on both workplace and residential location changes our understanding of disparities in air pollution exposure. In general, we observed higher workplace exposures relative to home exposures, as well as increased exposures for nonwhite and less educated workers relative to the national average. Workplace exposure disparities were higher among racial and ethnic groups and job types than by income, education, age, and sex. Not considering workplace exposures can lead to systematic underestimations in disparities in exposure among these subpopulations. We also quantified the error in assigning workers home instead of a weighted home-and-work exposure. We observed that biases in associations between PM2.5 and health impacts by using home instead of home-and-work exposure were the highest among urban, younger populations.


Asunto(s)
Contaminantes Atmosféricos , Contaminación del Aire , Humanos , Estados Unidos , Contaminantes Atmosféricos/análisis , Exposición a Riesgos Ambientales/análisis , Contaminación del Aire/análisis , Bases de Datos Factuales , Material Particulado/análisis
2.
PLoS Comput Biol ; 18(9): e1010472, 2022 09.
Artículo en Inglés | MEDLINE | ID: mdl-36149894

RESUMEN

The metagenome embedded in urban sewage is an attractive new data source to understand urban ecology and assess human health status at scales beyond a single host. Analyzing the viral fraction of wastewater in the ongoing COVID-19 pandemic has shown the potential of wastewater as aggregated samples for early detection, prevalence monitoring, and variant identification of human diseases in large populations. However, using census-based population size instead of real-time population estimates can mislead the interpretation of data acquired from sewage, hindering assessment of representativeness, inference of prevalence, or comparisons of taxa across sites. Here, we show that taxon abundance and sub-species diversisty in gut-associated microbiomes are new feature space to utilize for human population estimation. Using a population-scale human gut microbiome sample of over 1,100 people, we found that taxon-abundance distributions of gut-associated multi-person microbiomes exhibited generalizable relationships with respect to human population size. Here and throughout this paper, the human population size is essentially the sample size from the wastewater sample. We present a new algorithm, MicrobiomeCensus, for estimating human population size from sewage samples. MicrobiomeCensus harnesses the inter-individual variability in human gut microbiomes and performs maximum likelihood estimation based on simultaneous deviation of multiple taxa's relative abundances from their population means. MicrobiomeCensus outperformed generic algorithms in data-driven simulation benchmarks and detected population size differences in field data. New theorems are provided to justify our approach. This research provides a mathematical framework for inferring population sizes in real time from sewage samples, paving the way for more accurate ecological and public health studies utilizing the sewage metagenome.


Asunto(s)
COVID-19 , Microbioma Gastrointestinal , Microbioma Gastrointestinal/genética , Humanos , Pandemias , Densidad de Población , Aguas del Alcantarillado , Aguas Residuales
3.
Environ Sci Technol ; 57(26): 9427-9444, 2023 07 04.
Artículo en Inglés | MEDLINE | ID: mdl-37343238

RESUMEN

Mobile ambient air quality monitoring is rapidly changing the current paradigm of air quality monitoring and growing as an important tool to address air quality and climate data gaps across the globe. This review seeks to provide a systematic understanding of the current landscape of advances and applications in this field. We observe a rapidly growing number of air quality studies employing mobile monitoring, with low-cost sensor usage drastically increasing in recent years. A prominent research gap was revealed, highlighting the double burden of severe air pollution and poor air quality monitoring in low- and middle-income regions. Experiment-design-wise, the advances in low-cost monitoring technology show great potential in bridging this gap while bringing unique opportunities for real-time personal exposure, large-scale deployment, and diversified monitoring strategies. The median value of unique observations at the same location in spatial regression studies is ten, which can be used as a rule-of-thumb for future experiment design. Data-analysis-wise, even though data mining techniques have been extensively employed in air quality analysis and modeling, future research can benefit from exploring air quality information from nontabular data, such as images and natural language.


Asunto(s)
Contaminantes Atmosféricos , Contaminación del Aire , Contaminantes Atmosféricos/análisis , Monitoreo del Ambiente/métodos , Contaminación del Aire/análisis , Material Particulado/análisis
4.
Plant Foods Hum Nutr ; 78(1): 86-92, 2023 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-36334233

RESUMEN

Rice bran is an agro-industrial by-product of low added value that can be used to complement human nutritional needs. In this work, the profile of minerals, fatty acids and amino acids in brown rice bran was determined, aiming to evaluate its potential to complement the nutritional needs of different age groups, according to recommendations of regulatory agencies. The brown rice bran was supplied by a rice processing industry located in the south of the state of Rio Grande do Sul. Minerals were quantified using an emission spectrometer; the fatty acid profile was determined by gas chromatography and the amino acids were quantified by high-performance liquid chromatography with fluorescence (HPLC-FL). The main minerals were phosphorus (P), magnesium (Mg), potassium (K) and calcium (Ca) (2,933, 1,029, 211 and 56 mg / 100 g of rice bran). Saturated, monounsaturated and polyunsaturated fatty acids in rice bran were 22.4, 36.2 and 34.5% of lipid content, respectively. The polar, neutral and charged amino acids represented 8.8, 9.3 and 12.8% of the protein content, respectively. The composition of this co-product of rice supply chain is a good alternative to the new demand on plant-based food supplying the recommended daily intake (RDI) of national and international food polices.


Asunto(s)
Oryza , Humanos , Niño , Anciano , Oryza/química , Ácidos Grasos/análisis , Minerales , Calcio , Aminoácidos/metabolismo , Aminas/metabolismo
5.
Environ Sci Technol ; 56(11): 7328-7336, 2022 06 07.
Artículo en Inglés | MEDLINE | ID: mdl-35075907

RESUMEN

Predictive models based on mobile measurements have been increasingly used to understand the spatiotemporal variations of intraurban air quality. However, the effects of meteorological factors, which significantly affect the dispersion of air pollution, on the urban-form-air-quality relationship have not been understood on a granular level. We attempt to fill this gap by developing predictive models of particulate matter (PM) in the Bronx (New York City) using meteorological and urban form parameters. The granular PM data was collected by mobile low-cost sensors as the ground truth. To evaluate the effects of meteorological factors, we compared the performance of models using the urban form within fixed and wind-sensitive buffers, respectively. We find better predictive power in the wind-sensitive group (R = 0.85) for NC10 (number concentration for particles with diameters of 1 µm-10 µm) than the control group (R = 0.01), and modest improvements for PM2.5 (R = 0.84 for the wind sensitive group, R = 0.77 for the control group), indicating that incorporating meteorological factors improved the predictive power of our models. We also found that urban form factors account for 62.95% of feature importance for NC10 and 14.90% for PM2.5 (9.99% and 4.91% for 3-D and 2-D urban form factors, respectively) in our Random Forest models. It suggests the importance of incorporating urban form factors, especially for the uncommonly used 3-D characteristics, in estimating intraurban PM. Our method can be applied in other cities to better capture the influence of urban context on PM levels.


Asunto(s)
Contaminantes Atmosféricos , Contaminación del Aire , Contaminantes Atmosféricos/análisis , Contaminación del Aire/análisis , Ciudades , Monitoreo del Ambiente/métodos , Conceptos Meteorológicos , Material Particulado/análisis
6.
Aesthetic Plast Surg ; 46(1): 11-21, 2022 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-34309692

RESUMEN

INTRODUCTION: Mastopexy with an implant is undoubtedly one of the most challenging surgeries in cosmetic surgery since it involves two overlapping procedures. The aim of this study was to demonstrate that by using horizontal glandular flaps in the sulcus in mastopexy with implants, it is possible to reduce the number of postoperative complications. METHODS: Sixty-three female breast surgery patients with some degree of flaccidity who underwent surgery from July 2018 to January 2020 were selected. All surgeries were performed in one procedure with an initial resection of the excess skin associated with a horizontal flap of the upper pedicle that promoted the protection of the implants and decreased the surgical wound tension. RESULTS: Forty-seven patients were included in the sample, for a total of 94 breasts. The motivation of the surgery was esthetic in all cases. Related to complications, we had 1 (1.06%) case of seroma, 1 (1.06%) case suffering from areola necrosis, 6 (6.3%) cases with scar revisions, 10 (10.6%) cases with complications in the transition from the "T" and no case of hematoma, infection or extrusion of the implants. The follow-up time was 12 months. CONCLUSION: This technique allows the surgeon to perform a resection of excess skin and place the implants in one procedure, thereby decreasing the tension in the suture line, protecting the implants and forming a protective stabilizing brace in the mammary groove. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .


Asunto(s)
Mamoplastia , Estética , Femenino , Humanos , Mamoplastia/métodos , Pezones/cirugía , Estudios Retrospectivos , Colgajos Quirúrgicos/cirugía , Resultado del Tratamiento
7.
Cities ; 120: 103486, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-34642528

RESUMEN

The COVID-19 pandemic, an exceptional crisis, sparked the introduction of new digital infrastructure to halt the novel coronavirus's spread. This paper explores how such digital infrastructure's impact might reverberate over the long term, by comparing Singapore, Hong Kong, and mainland China's utilization of digital technology in response to the 2003 SARS outbreak, and their responses to the 2020 COVID-19 pandemic. We find that advancements in digital technology since 2003 have boosted governments' surveillance and segregation abilities substantially-most dramatically so in China. Even though some of these new digital interventions are ostensibly designed to be temporary ones to address the needs of the immediate crisis, we argue that the resultant extensions of state power experienced during COVID-19 are likely to have profound long-term effects because they fundamentally affect sociopolitical contexts, institutional capabilities, and digital cultures. We also find that the extent to which governments can extend digital surveillance and segregation abilities during the pandemic is contingent on their respective sociopolitical, institutional, and digital cultural contexts.

8.
Ecotoxicology ; 30(6): 1161-1169, 2021 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-33973134

RESUMEN

Antifouling paint particles (APPs) originate from vessel maintenance and cleaning activities and their potentially toxic components are found at high concentrations in nearby soils, yet no studies have investigated their toxicity to soil organisms. We investigated the effects of exposure to soils containing APPs on the mortality, biomass, and reproductive performance of the earthworm Eisenia andrei. Earthworms were exposed to contaminated soil from a boatyard and non-contaminated soils treated with different concentrations of APPs (0.01, 0.14 and 1.50%, w/w) for 56 days. An ecological risk assessment using a Hazard Quotient (HQ) was also carried out. Exposure to contaminated soils reduced worm survival, biomass, and reproductive performance and these effects were concentration-dependent. The HQ was high in soil samples with APPs in both acute and chronic tests, and copper contributed the most to the HQ. Copper, zinc, and lead had the highest concentrations and exceeded the Brazilian legal limits. A principal component analysis (PCA) was performed and showed that biomass and number of juveniles parameters was associated with the metals Cu, Sn and Zn, while the mortality parameter had no association with any analyzed metal. These findings highlighted that the synergistic effects of compounds present in the APPs, such as the booster biocides DCOIT, and metal mixtures should not be overlooked. We conclude that soils contaminated with APPs are toxic to earthworms. This reveals that the ecological impact of APPs goes beyond effects on aquatic environments, compromising key organisms of edaphic ecological processes.


Asunto(s)
Incrustaciones Biológicas , Oligoquetos , Contaminantes del Suelo , Animales , Incrustaciones Biológicas/prevención & control , Brasil , Pintura/toxicidad , Suelo , Contaminantes del Suelo/análisis , Contaminantes del Suelo/toxicidad
9.
Anal Chem ; 92(12): 8058-8063, 2020 06 16.
Artículo en Inglés | MEDLINE | ID: mdl-32425039

RESUMEN

A novel system for sample digestion was proposed based on microwave-induced combustion in disposable vessels (MIC-DV) for trace elements determination by inductively coupled plasma optical emission spectrometry (ICP-OES). As a proof of concept, botanical samples were digested by MIC-DV for further determination of Al, Cr, Cu, Fe, Mn, Sr, and Zn. The system consists of a quartz holder (a modified version of conventional MIC) placed inside disposable polypropylene (PP) vessels. The quartz holder was carefully designed to avoid excessive heating and damaging of the vessel walls. For the combustion, the PP vessels containing the quartz holder and sample were placed in a specially designed metallic rotor that prevents the heating of absorbing solution and allows the use of a domestic microwave oven for sample ignition. After combustion, the digestion vessel was shaken to ensure the analytes' absorption. The single-vessel principle was fulfilled, since no further dilution or liquid transfer was required and the same PP vessel used for digestion allowed solution storage until element determination. The influences of absorbing solution (diluted HNO3 and water) and sample mass (10 to 30 mg) were evaluated. By using the proposed MIC-DV system, low volumes of diluted absorbing solutions (5 mL of 1 mol L-1 HNO3) were possible, allowing the use of low reagent amounts and low energy consumption, since microwave irradiation is used only for sample ignition. The agreement with certified values ranged from 92 to 108% for all analytes, whereas the precision was below 15%. All of these advantages, combined with the use of low-cost disposable vessels and instrumentation, make MIC-DV suitable to be used for research and routine analysis.

10.
Environ Toxicol ; 35(5): 553-560, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-31846182

RESUMEN

Arsenic (As) can contaminate air, soil, water, and organisms through mobilization of natural mineralogical deposits or anthropogenic actions. Inorganic-As compounds are more toxic and widely available in aquatic environments, including drinking water reservoir catchments. Since little is known about its effects on prepubertal mammals, the present study focused on it. Hence, As was administered through drinking water to male Wistar rats from postnatal day 23 to 53. Negative control group received vehicle only (filtered water); As 1 group received AsNaO2 at 0.01 mg L-1 and As2 group received AsNaO2 at 10 mg L-1 . It was investigated hepatic and renal toxicity of AsNaO2 (ie, histopathology and apoptosis analysis), as well as its mutagenicity (ie, micronucleus test in liver and bone marrow), cytotoxicity (ie, frequency and type of erythrocytes in blood), and genotoxicity (ie, comet assay in blood). Also, As determination was performed in hepatic and renal tissues. Data obtained revealed that immature organisms present a pattern of arsenic accumulation similar to that observed in adults, suggesting similarity in metabolic processes. In addition, liver showed to be an important target tissue for As toxicity in these experimental conditions, exhibiting infiltrate of defense cells, DNA damages, and increased apoptosis rates.


Asunto(s)
Envejecimiento/efectos de los fármacos , Arsenitos/toxicidad , Enfermedad Hepática Inducida por Sustancias y Drogas/etiología , Daño del ADN , Contaminantes Ambientales/toxicidad , Micronúcleos con Defecto Cromosómico/inducido químicamente , Compuestos de Sodio/toxicidad , Envejecimiento/genética , Animales , Enfermedad Hepática Inducida por Sustancias y Drogas/genética , Ensayo Cometa , Relación Dosis-Respuesta a Droga , Masculino , Pruebas de Micronúcleos , Ratas , Ratas Wistar
11.
Environ Toxicol ; 34(1): 83-91, 2019 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-30291770

RESUMEN

For the first time, juvenile toxicity of inorganic arsenic (As) was investigated in male rats, focusing on reproductive effects. As is a metalloid naturally occurring in the environment, being the inorganic forms the most toxics. Contaminated drinking water and agricultural products are the main prospectors of intoxication for general population. In the present study, Wistar male rats (21 days old) were distributed into three groups (n = 10/group): control (received vehicle-filtered drinking water), As1 (received AsNaO2 at 0.01 mg L-1 ) and As2 (received AsNaO2 at 10 mg L-1 ). The animals were euthanized on PND 53. Testicular damages increased in As1 and As2 compared to control (ie, presence of vacuolization, acidophilic cells, and epithelium degeneration). Testicular interstitium of As1 and As2 presented fluid's increase and intense inflammatory infiltration. In the epididymis there was reduction of sperm amount in the lumen, besides epithelium areas presenting cribriform aspect in As1 and As2, exfoliation of cells in the light (in As1) and vacuoles (in As2). In epididymis interstitium, inflammatory infiltrates were observed in initial segment of As1 and As2. AsNaO2 changed immunolabeling pattern for androgen receptor in epididymis of As2, although serum testosterone levels was statistically comparable to control. Mass spectrometry revealed higher As concentrations in testis and epididymis of As2 compared to As1 and Control. These results indicate compromise of spermatogenesis and epididymal histophysiology in AsNaO2 -treated animals, possibly impairing sperm quality and fertility in long-term, even at low levels of exposure. Investigations about the reversibility of reproductive damages are necessary to better understand the mechanisms of As reproductive toxicity.


Asunto(s)
Arsenitos/toxicidad , Epidídimo/efectos de los fármacos , Epidídimo/patología , Maduración Sexual/efectos de los fármacos , Compuestos de Sodio/toxicidad , Espermatogénesis/efectos de los fármacos , Animales , Intoxicación por Arsénico/patología , Intoxicación por Arsénico/fisiopatología , Arsenitos/farmacología , Fertilidad/efectos de los fármacos , Masculino , Tamaño de los Órganos/efectos de los fármacos , Ratas , Ratas Wistar , Reproducción/efectos de los fármacos , Compuestos de Sodio/farmacología , Espermatozoides/efectos de los fármacos , Testículo/efectos de los fármacos , Pruebas de Toxicidad , Contaminantes Químicos del Agua/toxicidad
12.
J Dairy Sci ; 100(7): 5167-5175, 2017 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-28457548

RESUMEN

The aim of this research paper was to characterize coagulase-positive and coagulase-negative staphylococci from raw milk, Minas cheese, and production lines of Minas cheese processing. One hundred isolates from 3 different cheese producers were characterized using molecular approaches, such as PCR, molecular typing, and DNA sequencing. Staphylococcus aureus (88% of the isolates) was the most abundant followed by Staphylococcus epidermidis, Staphylococcus hyicus, and Staphylococcus warneri. Among the 22 enterotoxin genes tested, the most frequent was seh (62% of the isolates), followed by selx and ser. Hemolysin genes were widely distributed across isolates, and Panton-Valentine leukocidin and toxic shock syndrome toxin genes were also identified. Methicillin-resistant S. aureus were staphylococcal cassette chromosome mec III, IVa, IVd, and others nontypeable. In the phenotypic antibiotic resistance, multiresistant isolates were detected and resistance to penicillin was the most observed. Using spa typing, we identified several types and described a new one, t14969, isolated from cheese. These findings suggest that antibiotic resistance and potentially virulent strains from different sources can be found in the Brazilian dairy processing environment. Further research should be conducted with collaboration from regulatory agencies to develop programs of prevention of virulent and resistant strain dissemination in dairy products and the processing environment.


Asunto(s)
Antibacterianos/farmacología , Queso/microbiología , Farmacorresistencia Bacteriana Múltiple , Staphylococcus , Animales , Brasil , Farmacorresistencia Bacteriana Múltiple/genética , Pruebas de Sensibilidad Microbiana , Leche , Staphylococcus/clasificación , Staphylococcus/efectos de los fármacos , Staphylococcus/genética
13.
Anal Bioanal Chem ; 408(17): 4547-66, 2016 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-27020927

RESUMEN

Interest in the determination of elemental impurities in pharmaceuticals has increased in recent years because of changes in regulatory requirements and the need for changing or updating the current limit tests recommended in pharmacopeias. Inductively coupled plasma (ICP) optical emission spectrometry and ICP mass spectrometry are suitable alternatives to perform multielemental analysis for this purpose. The main advantages and limitations of these techniques are described, covering the applications reported in the literature in the last 10 years mainly for active pharmaceutical ingredients, raw materials, and pharmaceutical dosage forms. Strategies used for sample preparation, including dissolution in aqueous or organic solvents, extraction, wet digestion and combustion methods are described, as well as direct solid analysis and ICP-based systems applied for speciation analysis. Interferences observed during the analysis of pharmaceutical products using ICP-based methods are discussed. Methods currently recommended by pharmacopeias for elemental impurities are also covered, showing that the use of ICP-based methods could be considered as a trend in the determination of these impurities in pharmaceuticals. However, the development of a general method that is accurate for all elemental impurities and the establishment of an official method are still challenges. In this regard, the main drawbacks and suitable alternatives are discussed.


Asunto(s)
Espectrometría de Masas/métodos , Preparaciones Farmacéuticas/química
14.
BMC Microbiol ; 14: 267, 2014 Oct 20.
Artículo en Inglés | MEDLINE | ID: mdl-25361869

RESUMEN

BACKGROUND: Chromobacterium violaceum is a bacterium commonly found in tropical and subtropical regions and is associated with important pharmacological and industrial attributes such as producing substances with therapeutic properties and synthesizing biodegradable polymers. Its genome was sequenced, however, approximately 40% of its genes still remain with unknown functions. Although C. violaceum is known by its versatile capacity of living in a wide range of environments, little is known on how it achieves such success. Here, we investigated the proteomic profile of C. violaceum cultivated in the absence and presence of high iron concentration, describing some proteins of unknown function that might play an important role in iron homeostasis, amongst others. RESULTS: Briefly, C. violaceum was cultivated in the absence and in the presence of 9 mM of iron during four hours. Total proteins were identified by LC-MS and through the PatternLab pipeline. Our proteomic analysis indicates major changes in the energetic metabolism, and alterations in the synthesis of key transport and stress proteins. In addition, it may suggest the presence of a yet unidentified operon that could be related to oxidative stress, together with a set of other proteins with unknown function. The protein-protein interaction network also pinpointed the importance of energetic metabolism proteins to the acclimatation of C. violaceum in high concentration of iron. CONCLUSIONS: This is the first proteomic analysis of the opportunistic pathogen C. violaceum in the presence of high iron concentration. Our data allowed us to identify a yet undescribed operon that might have a role in oxidative stress defense. Our work provides new data that will contribute to understand how this bacterium achieve its capacity of surviving in harsh conditions as well as to open a way to explore the yet little availed biotechnological characteristics of this bacterium with the further exploring of the proteins of unknown function that we showed to be up-regulated in high iron concentration.


Asunto(s)
Proteínas Bacterianas/análisis , Chromobacterium/química , Chromobacterium/efectos de los fármacos , Hierro/metabolismo , Proteoma/análisis , Cromatografía Liquida , Chromobacterium/crecimiento & desarrollo , Chromobacterium/metabolismo , Medios de Cultivo/química , Humanos , Espectrometría de Masas , Operón , Proteómica
15.
PLoS One ; 19(6): e0298826, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38829889

RESUMEN

AIM: To test the association between sociodemographic and social characteristics with COVID-19 cases and deaths in small and large Brazilian cities. METHODS: This ecological study included COVID-19 data available in State Health Secretaries (managed by brasil.io API) and three national databases (IBGE, DATASUS and Embrapa). Temporal spread of COVID-19 in Brazil during the first year considered as outcome: a) days until 1st case in each city since 1st in the country; b) days until 1,000 cases/100,000 inhabitants since 1st case in each city; c) days until 1st death until 50 deaths/100,000 inhabitants. Covariates included geographic region, city social and environmental characteristics, housing conditions, job characteristics, socioeconomic and inequalities characteristics, and health services and coverage. The analysis were stratified by city size into small (<100,000 inhabitants) and large cities (≥100,00 inhabitants). Multiple linear regressions were performed to test associations of all covariates to adjust to potential confounders. RESULTS: In small cities, the first cases were reported after 82.2 days and 1,000 cases/100,000 were reported after 117.8 days, whereas in large cities these milestones were reported after 32.1 and 127.7 days, respectively. For first death, small and large cities took 121.6 and 36.0 days, respectively. However, small cities were associated with more vulnerability factors to first case arrival in 1,000 cases/100,000 inhabitants, first death and 50 deaths/100,000 inhabitants. North and Northeast regions positively associated with faster COVID-19 incidence, whereas South and Southeast were least. CONCLUSION: Social and built environment characteristics and inequalities were associated with COVID-19 cases spread and mortality incidence in Brazilian cities.


Asunto(s)
COVID-19 , Ciudades , COVID-19/epidemiología , COVID-19/mortalidad , Humanos , Brasil/epidemiología , Ciudades/epidemiología , Factores Socioeconómicos , SARS-CoV-2/aislamiento & purificación
16.
Anal Chem ; 85(1): 374-80, 2013 Jan 02.
Artículo en Inglés | MEDLINE | ID: mdl-23171470

RESUMEN

An effective approach to the digestion of fluoropolymers for the determination of Ag, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, and Ni impurities has been developed using microwave-induced combustion (MIC) in closed quartz vessels pressurized with oxygen. Samples that were examined included the following: polytetrafluorethylene (PTFE); polytetrafluoroethylene with an additional modifier, perfluoropropylvinylether (PTFE-TFM); and fluorinated ethylene propylene (FEP). A quartz device was used as a sample holder, and the influence of the absorber solution was evaluated. Determination of trace elements was performed by inductively coupled plasma-optical emission and mass spectrometry. Neutron activation analysis (NAA) was used for validation purposes. Results were also compared to those obtained using microwave-assisted acid extraction in high-pressure closed systems. Dilute nitric acid (5 mol L(-1)), which was selected as the absorbing medium, was used to reflux the sample for 5 min after the combustion. Using these conditions, agreement for all analytes was better than 98% when compared to values determined by NAA. The residual carbon content in the digests was lower than 1%, illustrating the high efficiency of the method. Up to 8 samples could be digested within 30 min using MIC, providing a suitable throughput, taking into account the inertness of such samples.


Asunto(s)
Espectrometría de Masas , Microondas , Politetrafluoroetileno/química , Oligoelementos/análisis , Neutrones , Ácido Nítrico/química , Cuarzo/química
17.
Anal Chem ; 85(10): 5015-22, 2013 May 21.
Artículo en Inglés | MEDLINE | ID: mdl-23614538

RESUMEN

This paper reports, for the first time, the development of an analytical method employing modified matrix solid-phase dispersion (MSPD) for the extraction of CH3Hg(+) and Hg(2+) species from fish samples. Separation and determination of mercury species were performed by gas chromatography coupled to mass spectrometry (GC/MS). Important MSPD parameters, such as sample mass, type and mass of solid support, concentration of extraction solution (HCl and NaCl), and stirring time, were investigated by the response surface methodology. The derivatization step and the separation of mercury species were also evaluated for the determination by GC/MS. Quantitative recoveries were obtained with 0.2 g of fish sample, 0.5 g of SiO2 as the solid support, 0.5 mol L(-1) NaCl and 4.2 mol L(-1) HCl as the extraction solution, and 1 min stirring time. The MSPD method showed to be suitable for the extraction and determination of mercury species in certified reference materials of dogfish liver (DOLT-3) and dogfish muscle (DORM-2). It had good agreement (about 99%) with the certified values, and the relative standard deviation was lower than 9.5%. The limits of detection were 0.06 and 0.12 µg g(-1), for CH3Hg(+) and Hg(2+), respectively. A matrix effect was observed, and the quantification was carried out by the matrix-matched calibration. The method was applied to tuna fish ( Thunnus thynnus ), angel shark ( Squatina squatina ), and guitarfish ( Rhinobatos percellens ) samples. The results of the mercury speciation by MPSD and GC/MS were compared to the total mercury concentration determined by flow injection cold vapor generation inductively coupled plasma mass spectrometry, after microwave-assisted digestion. Agreement ranged from 102% to 105%.


Asunto(s)
Métodos Analíticos de la Preparación de la Muestra/métodos , Peces , Mercurio/análisis , Mercurio/aislamiento & purificación , Compuestos de Metilmercurio/análisis , Compuestos de Metilmercurio/aislamiento & purificación , Extracción en Fase Sólida/métodos , Animales , Contaminación de Alimentos/análisis , Cromatografía de Gases y Espectrometría de Masas , Límite de Detección
18.
Anal Bioanal Chem ; 405(24): 7615-42, 2013 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-23780223

RESUMEN

Fluorine, chlorine, bromine, and iodine have been studied in biological samples and other related matrices owing to the need to understand the biochemical effects in living organisms. In this review, the works published in last 20 years are covered, and the main topics related to sample preparation methods and analytical techniques commonly used for fluorine, chlorine, bromine, and iodine determination in biological samples, food, drugs, and plants used as food or with medical applications are discussed. The commonest sample preparation methods, as extraction and decomposition using combustion and pyrohydrolysis, are reviewed, as well as spectrometric and electroanalytical techniques, spectrophotometry, total reflection X-ray fluorescence, neutron activation analysis, and separation systems using chromatography and electrophoresis. On this aspect, the main analytical challenges and drawbacks are highlighted. A discussion related to the availability of certified reference materials for evaluation of accuracy is also included, as well as a discussion of the official methods used as references for the determination of halogens in the samples covered in this review.


Asunto(s)
Bioensayo/normas , Química Analítica/normas , Halógenos/análisis , Animales , Bioensayo/tendencias , Halógenos/química , Humanos
19.
J Sep Sci ; 36(20): 3411-8, 2013 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-23946243

RESUMEN

This work reports the development of a dispersive liquid-liquid microextraction method for the simultaneous extraction, preconcentration, and derivatization of Hg(2+) and CH3Hg(+) species from water samples for further determination by GC-MS. Some parameters of the proposed method, such as volume and type of disperser and extraction solvent, and Na[B(C6H5)4] concentration were investigated using response surface methodology. Suitable recoveries were obtained using 80 µL C2 Cl4 (as extraction solvent), 1000 µL ethanol (as disperser solvent), and 300 µL 2.1 mmol/L Na[B(C6H5)4] (as derivatizing agent). Accuracy was evaluated in terms of recovery and ranged from 87 to 99% with RSD values <7%. In addition, a certified reference material of water (NIST 1641d) was analyzed and agreed with the certified value about 107% (for Hg(2+)), with RSD values <8.5%. LODs were 0.3 and 0.2 µg/L, with enrichment factors of 112 and 115 for Hg(2+) and CH3Hg(+), respectively. The optimized method was applied for the determination of Hg(2+) and CH3Hg(+) in tap, well, and lake water samples.


Asunto(s)
Cromatografía de Gases y Espectrometría de Masas/métodos , Microextracción en Fase Líquida/métodos , Compuestos de Mercurio/análisis , Compuestos de Mercurio/aislamiento & purificación , Compuestos de Metilmercurio/análisis , Compuestos de Metilmercurio/aislamiento & purificación , Contaminantes Químicos del Agua/análisis , Contaminantes Químicos del Agua/aislamiento & purificación , Agua Dulce/química
20.
PLoS One ; 18(2): e0279906, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36791064

RESUMEN

Crime has major influences in urban life, from migration and mobility patterns, to housing prices and neighborhood liveability. However, urban crime studies still largely rely on static data reported by the various institutions and organizations dedicated to urban safety. In this paper, we demonstrate how the use of digital technologies enables the fine-grained analysis of specific crimes over time and space. This paper leverages the rise of ubiquitous sensing to investigate the issue of bike theft in Amsterdam-a city with a dominant cycling culture, where reportedly more than 80,000 bikes are stolen every year. We use active location tracking to unveil where stolen bikes travel to and what their temporal patterns are. This is the first study using tracking technologies to focus on two critical aspects of contemporary cities: active mobility and urban crime.


Asunto(s)
Ciclismo , Robo , Ciudades , Crimen , Vivienda
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