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1.
J Environ Manage ; 360: 121128, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38776661

RESUMEN

Vegetation regulates microclimate stability through biophysical mechanisms such as evaporation, transpiration and shading. Therefore, thermal conditions in tree-dominated habitats will frequently differ significantly from standardized free-air temperature measurements. The ability of forests to buffer temperatures nominates them as potential sanctuaries for tree species intolerant to the increasingly challenging thermal conditions established by climate change. Although many factors influencing thermal conditions beneath the vegetation cover have been ascertained, the role of three-dimensional vegetation structure in regulating the understory microclimate remains understudied. Recent advances in remote sensing technologies, such as terrestrial laser scanning, have allowed scientists to capture the three-dimensional structural heterogeneity of vegetation with a high level of accuracy. Here, we examined the relationships between vegetation structure parametrized from voxelized laser scanning point clouds, air and soil temperature ranges, as well as offsets between field-measured temperatures and gridded free-air temperature estimates in 17 sites in a tropical mountain ecosystem in Southeast Kenya. Structural diversity generally exerted a cooling effect on understory temperatures, but vertical diversity and stratification explained more variation in the understory air and soil temperature ranges (30%-40%) than canopy cover (27%), plant area index (24%) and average stand height (23%). We also observed that the combined effects of stratification, canopy cover and elevation explained more than half of the variation (53%) in understory air temperature ranges. Stratification's attenuating effect was consistent across different levels of elevation. Temperature offsets between field measurements and free-air estimates were predominantly controlled by elevation, but stratification and structural diversity were influential predictors of maximum and median temperature offsets. Moreover, stable understory temperatures were strongly associated with a large offset in daytime maximum temperatures, suggesting that structural diversity primarily contributes to thermal stability by cooling daytime maximum temperatures. Our findings shed light on the thermal influence of vertical vegetation structure and, in the context of tropical land-use change, suggest that decision-makers aiming to mitigate the thermal impacts of land conversion should prioritize management practices that preserve structural diversity by retaining uneven-aged trees and mixing plant species of varying sizes, e.g., silvopastoral, or agroforestry systems.


Asunto(s)
Cambio Climático , Ecosistema , Microclima , Clima Tropical , Árboles , Humanos , Temperatura , Bosques , Biodiversidad , Kenia
2.
Artículo en Inglés | MEDLINE | ID: mdl-38613622

RESUMEN

Self-mutilation lesions can represent a clinical diagnosis challenge for healthcare professionals, as patients do not admit to self-mutilation. This leads to failed diagnoses due to the similarity of this condition to other diseases. Searches on the subject were carried out at the PubMed, Periódicos Capes, Scopus, Science Direct and WoS databases, according to the following inclusion criteria: articles in English, Portuguese or Spanish, published from 2018 to June 2023, encompassing case reports, case series and literature reviews. Men are slight more affected by self-mutilation injuries, also presenting the most serious lesions. Self-mutilation injuries are reported globally, mostly in the Asian and American continents. Clinical presentations are varied, but morphology is, in most cases, associated to the form/instrument used for self-mutilation. Greater evidence of diagnosed mental disorders in women and underreporting of these cases in men due to low demands for specialized treatment are noted. A higher prevalence of self-mutilation lesions was verified for men, affecting a wide age range, with the highest number of cases in the USA. The most affected body areas are arms and external genitalia, mostly due to knife use. An association between self-mutilation injuries and mental disorders is clear, with most cases being previously undiagnosed.

3.
Nat Commun ; 15(1): 549, 2024 Jan 23.
Artículo en Inglés | MEDLINE | ID: mdl-38263406

RESUMEN

Temperature is a fundamental driver of species distribution and ecosystem functioning. Yet, our knowledge of the microclimatic conditions experienced by organisms inside tropical forests remains limited. This is because ecological studies often rely on coarse-gridded temperature estimates representing the conditions at 2 m height in an open-air environment (i.e., macroclimate). In this study, we present a high-resolution pantropical estimate of near-ground (15 cm above the surface) temperatures inside forests. We quantify diurnal and seasonal variability, thus revealing both spatial and temporal microclimate patterns. We find that on average, understory near-ground temperatures are 1.6 °C cooler than the open-air temperatures. The diurnal temperature range is on average 1.7 °C lower inside the forests, in comparison to open-air conditions. More importantly, we demonstrate a substantial spatial variability in the microclimate characteristics of tropical forests. This variability is regulated by a combination of large-scale climate conditions, vegetation structure and topography, and hence could not be captured by existing macroclimate grids. Our results thus contribute to quantifying the actual thermal ranges experienced by organisms inside tropical forests and provide new insights into how these limits may be affected by climate change and ecosystem disturbances.


Asunto(s)
Ecosistema , Bosques , Temperatura , Cambio Climático , Sistemas de Computación
4.
Nat Commun ; 14(1): 8129, 2023 Dec 14.
Artículo en Inglés | MEDLINE | ID: mdl-38097604

RESUMEN

Habitat fragmentation could potentially affect tree architecture and allometry. Here, we use ground surveys of terrestrial LiDAR in Central Amazonia to explore the influence of forest edge effects on tree architecture and allometry, as well as forest biomass, 40 years after fragmentation. We find that young trees colonising the forest fragments have thicker branches and architectural traits that optimise for light capture, which result in 50% more woody volume than their counterparts of similar stem size and height in the forest interior. However, we observe a disproportionately lower height in some large trees, leading to a 30% decline in their woody volume. Despite the substantial wood production of colonising trees, the lower height of some large trees has resulted in a net loss of 6.0 Mg ha-1 of aboveground biomass - representing 2.3% of the aboveground biomass of edge forests. Our findings indicate a strong influence of edge effects on tree architecture and allometry, and uncover an overlooked factor that likely exacerbates carbon losses in fragmented forests.


Asunto(s)
Bosques , Árboles , Biomasa , Ecosistema , Madera , Clima Tropical
5.
Sci Total Environ ; 867: 161320, 2023 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-36603629

RESUMEN

Savannas contribute to ca. 30 % of the total terrestrial net primary productivity and are responsible for significant carbon storage. Savannas in South America are mostly found within the Cerrado Domain, which is very threatened and presents remarkable carbon pools. Herein, we used a unique dataset of 21 Cerrado sites spanning 144 permanent field plots in Southeastern Brazil to assess the general patterns of above and belowground carbon stocks. We identified the main environmental and tree diversity drivers of aboveground wood carbon and productivity, belowground carbon stocks (roots and soil), carbon ratios (root:shoot and above:below) and total carbon stocks in the Cerrado through a combination of climatic estimates, fire frequency data, field measurements of vegetation, roots, soil carbon, nutrients and texture, and assessment of different components of diversity (species, functional and phylogenetic). Our findings reveal average aboveground, root, and soil carbon stocks of 20.4, 14.24, and 123.13 Mg.ha-1, respectively. Average Root:Shoot and Above:Below confirm the "inverted forest" concept with values of 1.58 and 0.21, respectively. Total carbon was 145.62 Mg.ha-1, reinforcing the great amount of carbon storage in the Cerrado and its role in the carbon cycle and dynamics. Tree diversity variables (mainly species diversity and functional composition variables) had more significant effects over aboveground variables, whereas environmental variables had more significant effects over belowground variables. Ratios and total carbon mixed up these effects. The impressive values of carbon storage, especially belowground, point out the need to better manage and protect the Cerrado. Moreover, our findings might be particularly relevant for discussions on restoration programs focused on the trees-for­carbon idea that do not consider species diversity and belowground carbon stocks.


Asunto(s)
Carbono , Pradera , Carbono/análisis , Brasil , Filogenia , Bosques , Suelo , Ecosistema , Biomasa
6.
Nat Commun ; 13(1): 917, 2022 02 17.
Artículo en Inglés | MEDLINE | ID: mdl-35177619

RESUMEN

Predictions of the magnitude and timing of leaf phenology in Amazonian forests remain highly controversial. Here, we use terrestrial LiDAR surveys every two weeks spanning wet and dry seasons in Central Amazonia to show that plant phenology varies strongly across vertical strata in old-growth forests, but is sensitive to disturbances arising from forest fragmentation. In combination with continuous microclimate measurements, we find that when maximum daily temperatures reached 35 °C in the latter part of the dry season, the upper canopy of large trees in undisturbed forests lost plant material. In contrast, the understory greened up with increased light availability driven by the upper canopy loss, alongside increases in solar radiation, even during periods of drier soil and atmospheric conditions. However, persistently high temperatures in forest edges exacerbated the upper canopy losses of large trees throughout the dry season, whereas the understory in these light-rich environments was less dependent on the altered upper canopy structure. Our findings reveal a strong influence of edge effects on phenological controls in wet forests of Central Amazonia.


Asunto(s)
Bosques , Hojas de la Planta/fisiología , Árboles/fisiología , Brasil , Luz , Microclima , Estaciones del Año , Suelo/química , Agua/química
7.
Rev. ABENO ; 21(1): 1639, dez. 2021. tab, ilus
Artículo en Portugués | BBO - Odontología | ID: biblio-1373360

RESUMEN

Este estudo visa analisar a relevância dosEstágios Supervisionados em Odontologia no Sistema único de Saúde para o ensino, serviço e comunidade. Trata-se deuma revisão de literatura integrativacombusca nas bases de dadosBVS/LILACS, SciELO e Google Acadêmico. Os estudos para análise foram escolhidos após o estabelecimento de critérios de inclusão(artigos publicados nos últimos 5 anosque tratem das percepções dos envolvidos nessa vivência de integração,autores clássicos, teses, relatos de experiência, artigos em português, inglês e espanhol)e exclusão(artigos semDOIoutratando deestágiosem outras áreasesistemas de saúde). Assim, após a busca inicial, foram selecionados 113 estudosno total sendo 25, 8e 100,respectivamente,da BVS/LILACS, SciELO e Google Acadêmico. No entanto, após a leitura dos artigos na íntegra somente 17publicaçõesforam selecionadas. Dessa forma, das competênciasgerais apresentadas pelas Diretrizes Curriculares Nacionais em Odontologia, os estudos indicam que trabalho em equipe, atenção integral à saúde do usuário e comunicação adequada com usuários e membros da equipe são as características mais estimuladasna formação dos estudantes. Ademais, destaca-se a atenção primária como principal cenário de atuação do estagiário, compouco enfoque nos demais níveis de atenção. Analisou-se que perante as fragilidades desse processo, o estudante, sob orientação da preceptoria, deve adaptar-se àrealidade vivenciada para exercer a sua função com sucesso. Logo, o estágio insere o estudante na realidade profissional,além de trabalhar as suas insegurançase a capacidade de adaptação (AU).


This study aims to analyze the relevance of Supervised Internships in Dentistry at SUS for teaching, serviceand community. This is an integrative literature review, which was elaborated through a search in the databases: BVS/LILACS, SCIELO and GOOGLE ACADEMIC. The studies for analysis were chosen after the establishment of inclusion criteria: articles publishedin the last 5 years dealing with the perceptions of those involved in this integration experience, classical authors, theses, experience reports, articles in Portuguese, English and Spanish; and exclusion: articles without DOI and dealing with internshipsin other areas and health systems. Thus, after reading the titles, 113 studies were selected in total, 25, 8 and 100 respectively from the BVS/LILACS, SCIELO and Google academic. However, after reading the articles in full, only 17 publications were selected. Thus, from the general characteristics presented by the National Curriculum Guidelines in dentistry, studies indicate that teamwork, comprehensive care to the user's health and adequate communication with users and team members are the characteristicsmost encouraged by academics. Furthermore, primary care is highlighted as the main scenario in which the intern works, with little focus on other levels of care. It was analyzed that, in view of the weaknesses of this process, the student, under the guidance of the preceptorship, must adapt to the reality experienced in order to successfully perform his role. Therefore, the internship inserts the student into the professional reality, in addition to working on their insecurities and adaptability (AU).


Asunto(s)
Atención Primaria de Salud , Sistema Único de Salud , Prácticas Clínicas , Atención Integral de Salud , Curriculum , Preceptoría , Relaciones Interpersonales
9.
Nutrients ; 13(4)2021 Apr 02.
Artículo en Inglés | MEDLINE | ID: mdl-33918334

RESUMEN

Dry extracts from the Eurasian plants, Ajuga turkestanica, Eurycoma longifolia, and Urtica dioica have been used as anabolic supplements, despite the limited scientific data on these effects. To assess their actions on early sarcopenia signs, male and female castrated mice were supplemented with lyophilized extracts of the three plants, isolated or in association (named TLU), and submitted to resistance exercise. Ovariectomy (OVX) led to body weight increase and non-high-density cholesterol (HDL) cholesterol elevation, which had been restored by exercise plus U. dioica extract, or by exercise and TLU, respectively. Orchiectomy (ORX) caused skeletal muscle weight loss, accompanied by increased adiposity, being the latter parameter reduced by exercise plus E. longifolia or U. dioica extracts. General physical activity was improved by exercise plus herbal extracts in either OVX or ORX animals. Exercise combined with TLU improved resistance to fatigue in OVX animals, though A. turkestanica enhanced the grip strength in ORX mice. E. longifolia or TLU also reduced the ladder climbing time in ORX mice. Resistance exercise plus herbal extracts partly altered gastrocnemius fiber size frequencies in OVX or ORX mice. We provide novel data that tested ergogenic extracts, when combined with resistance exercise, improved early sarcopenia alterations in castrated male and female mice.


Asunto(s)
Anabolizantes/farmacología , Suplementos Dietéticos , Magnoliopsida/química , Condicionamiento Físico Animal/fisiología , Extractos Vegetales/farmacología , Adiposidad/efectos de los fármacos , Ajuga/química , Animales , Modelos Animales de Enfermedad , Eurycoma/química , Femenino , Masculino , Ratones , Músculo Esquelético/efectos de los fármacos , Orquiectomía , Ovariectomía , Sarcopenia/etiología , Sarcopenia/prevención & control , Urtica dioica/química
10.
Nat Commun ; 12(1): 1526, 2021 03 09.
Artículo en Inglés | MEDLINE | ID: mdl-33750781

RESUMEN

The past 40 years in Southeast Asia have seen about 50% of lowland rainforests converted to oil palm and other plantations, and much of the remaining forest heavily logged. Little is known about how fragmentation influences recovery and whether climate change will hamper restoration. Here, we use repeat airborne LiDAR surveys spanning the hot and dry 2015-16 El Niño Southern Oscillation event to measure canopy height growth across 3,300 ha of regenerating tropical forests spanning a logging intensity gradient in Malaysian Borneo. We show that the drought led to increased leaf shedding and branch fall. Short forest, regenerating after heavy logging, continued to grow despite higher evaporative demand, except when it was located close to oil palm plantations. Edge effects from the plantations extended over 300 metres into the forests. Forest growth on hilltops and slopes was particularly impacted by the combination of fragmentation and drought, but even riparian forests located within 40 m of oil palm plantations lost canopy height during the drought. Our results suggest that small patches of logged forest within plantation landscapes will be slow to recover, particularly as ENSO events are becoming more frequent.


Asunto(s)
El Niño Oscilación del Sur/efectos adversos , Bosques , Árboles , Clima Tropical , Arecaceae , Asia Sudoriental , Borneo , Cambio Climático , Sequías , Ecología , Humanos , Malasia , Hojas de la Planta , Bosque Lluvioso
11.
Glob Chang Biol ; 27(1): 177-189, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-33118242

RESUMEN

Tall trees are key drivers of ecosystem processes in tropical forest, but the controls on the distribution of the very tallest trees remain poorly understood. The recent discovery of grove of giant trees over 80 meters tall in the Amazon forest requires a reevaluation of current thinking. We used high-resolution airborne laser surveys to measure canopy height across 282,750 ha of old-growth and second-growth forests randomly sampling the entire Brazilian Amazon. We investigated how resources and disturbances shape the maximum height distribution across the Brazilian Amazon through the relations between the occurrence of giant trees and environmental factors. Common drivers of height development are fundamentally different from those influencing the occurrence of giant trees. We found that changes in wind and light availability drive giant tree distribution as much as precipitation and temperature, together shaping the forest structure of the Brazilian Amazon. The location of giant trees should be carefully considered by policymakers when identifying important hot spots for the conservation of biodiversity in the Amazon.


Asunto(s)
Ecosistema , Árboles , Biodiversidad , Brasil , Bosques , Clima Tropical
12.
Food Chem X ; 2: 100028, 2019 Jun 30.
Artículo en Inglés | MEDLINE | ID: mdl-31432014

RESUMEN

The consumption of rice milk has increased, mainly by individuals intolerant to lactose or allergic to cow milk. However, rice milk contains As. In this sense, the concentration of As in rice milk should be controlled. In the present study it is proposed a methodology for determination of As(III), dimethylarsenic (DMA), monomethylarsenic (MMA) and As(V) species in rice milk using LC-ICP-MS. The main features of the methodology are fast analysis, easy and simple sample preparation, where the sample is 3-fold diluted in the mobile phase and then filtered. The four arsenic species investigated were detected in the analysed samples, being As(V) the main species. The limit of quantification of the method ranges from 0.25 to 0.43 µg L-1 As. The analyte recovery ranged from 81 to 116% for samples spiked to 1.00 µg L-1 or 5.00 µg L-1 As and the relative standard deviation was better than 5%.

13.
Conserv Biol ; 32(6): 1457-1463, 2018 12.
Artículo en Inglés | MEDLINE | ID: mdl-29923638

RESUMEN

In 2008, a group of conservation scientists compiled a list of 100 priority questions for the conservation of the world's biodiversity. However, now almost a decade later, no one has yet published a study gauging how much progress has been made in addressing these 100 high-priority questions in the peer-reviewed literature. We took a first step toward reexamining the 100 questions to identify key knowledge gaps that remain. Through a combination of a questionnaire and a literature review, we evaluated each question on the basis of 2 criteria: relevance and effort. We defined highly relevant questions as those that - if answered - would have the greatest impact on global biodiversity conservation and quantified effort based on the number of review publications addressing a particular question, which we used as a proxy for research effort. Using this approach, we identified a set of questions that, despite being perceived as highly relevant, have been the focus of relatively few review publications over the past 10 years. These questions covered a broad range of topics but predominantly tackled 3 major themes: conservation and management of freshwater ecosystems, role of societal structures in shaping interactions between people and the environment, and impacts of conservation interventions. We believe these questions represent important knowledge gaps that have received insufficient attention and may need to be prioritized in future research.


Asunto(s)
Conservación de los Recursos Naturales , Ecosistema , Biodiversidad , Agua Dulce
14.
Carbohydr Polym ; 189: 257-266, 2018 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-29580407

RESUMEN

Waste coffee-grounds (WCG), a poorly explored source of biocompounds, were combined with chitosan (Cs) and poly(vinyl alcohol) (PVA) in order to obtain composites. Overall, WCG showed a good interaction with the polymeric matrix and good dispersibility up to 10 wt-%. At 5 wt-% WCG, the composite exhibited a noticeable enhancement (from 10 to 44%) of the adsorption of pharmaceuticals (metamizol (MET), acetylsalicylic acid (ASA), acetaminophen (ACE), and caffeine (CAF)) as compared to the pristine sample. The highest removal efficiency was registered at pH 6 and the removal followed the order ASA > CAF > ACE > MET. For all pharmaceuticals, the adsorption kinetics was found to follow the pseudo-second order model, while the adsorption mechanism was explained by the Freundlich isotherm. Reuse experiments indicated that the WCG-containing composite has an attractive cost-effectiveness since it presented a remarkable reusability in at least five consecutive adsorption/desorption cycles.


Asunto(s)
Quitosano/química , Café/química , Purificación del Agua/métodos , Acetaminofén/química , Adsorción , Aspirina/química , Cafeína/química , Dipirona/química , Cinética , Preparaciones Farmacéuticas/química
15.
Conserv Lett ; 11(5): e12564, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-31031821

RESUMEN

Conservation policy decisions can suffer from a lack of evidence, hindering effective decision-making. In nature conservation, studies investigating why policy is often not evidence-informed have tended to focus on Western democracies, with relatively small samples. To understand global variation and challenges better, we established a global survey aimed at identifying top barriers and solutions to the use of conservation science in policy. This obtained the views of 758 people in policy, practice, and research positions from 68 countries across six languages. Here we show that, contrary to popular belief, there is agreement between groups about how to incorporate conservation science into policy, and there is thus room for optimism. Barriers related to the low priority of conservation were considered to be important, while mainstreaming conservation was proposed as a key solution. Therefore, priorities should focus on convincing the public of the importance of conservation as an issue, which will then influence policy-makers to adopt pro-environmental long-term policies.

16.
Talanta ; 170: 488-495, 2017 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-28501200

RESUMEN

A calibration strategy using porous nylon disks and reference solutions is proposed for the first time for matrix matching and determination of As, Ba, Cd, Cr, Pb, Sr and Zn in polymers by laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS). Polymer samples commonly used in contact with food were analyzed. The procedure consists on the use of porous nylon disks as support for a dried droplet reference solution. Calibration in the range of 0.50-190µgg-1 for Ba, Cd, Cr, Pb, Sr and Zn and from 0.30-9.0µgg-1 for As was used. Laser and ICP-MS instrument conditions were evaluated in order to achieve the best signal-to-background ratio. The radiofrequency power and carrier gas flow rate were fixed at 1300W and 1.25Lmin-1, respectively. Spot size, repetition rate, scan line speed and laser fluency were set to 100µm, 20Hz, 100µms-1 and 17.9Jcm-2, respectively, as the established conditions for analysis of standards and samples. By using these conditions, limits of detection, estimated considering B+3s (where B is the value of the blank and s is the standard deviation of 10 measurements of the blank), ranged from 0.09µgg-1 (208Pb) to 1.09 (53Cr) and 0.05µgg-1 (208Pb) to 2.10 (53Cr) for calibration with and without 13C as internal standard (IS). In spite to the use of nylon for matrix matching of different polymeric matrices, the normalization with 13C as IS was also evaluated. The precision of the method is relatively good (RSD<20%), and the accuracy of the method, evaluated by analysis of certified reference materials (CRM) and by comparison with results obtained from solution analysis by ICP-MS after sample decomposition by microwave induced combustion (MIC) is relatively good. The suitability of the proposed method resulted in direct and reliable analyses of polymer samples with a simplified or unnecessary sample preparation step. In addition, the calibration with dried droplet reference solutions may be considered a promising procedure in view of its advantages to other forms of calibration, as the use of CRM or the preparation of synthetic standards. The use of porous nylon disks spiked with reference solutions for calibration is the main advantage of the present work.


Asunto(s)
Embalaje de Alimentos/métodos , Espectrometría de Masas/métodos , Metales/análisis , Polímeros/química , Calibración , Diseño de Equipo , Espectrometría de Masas/instrumentación
17.
PLoS One ; 11(5): e0154738, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27187074

RESUMEN

Tree stem form in native tropical forests is very irregular, posing a challenge to establishing taper equations that can accurately predict the diameter at any height along the stem and subsequently merchantable volume. Artificial intelligence approaches can be useful techniques in minimizing estimation errors within complex variations of vegetation. We evaluated the performance of Random Forest® regression tree and Artificial Neural Network procedures in modelling stem taper. Diameters and volume outside bark were compared to a traditional taper-based equation across a tropical Brazilian savanna, a seasonal semi-deciduous forest and a rainforest. Neural network models were found to be more accurate than the traditional taper equation. Random forest showed trends in the residuals from the diameter prediction and provided the least precise and accurate estimations for all forest types. This study provides insights into the superiority of a neural network, which provided advantages regarding the handling of local effects.


Asunto(s)
Inteligencia Artificial , Ecosistema , Modelos Teóricos , Árboles , Algoritmos , Brasil , Bosques , Geografía , Redes Neurales de la Computación , Árboles/crecimiento & desarrollo
18.
J Pharm Biomed Anal ; 123: 10-5, 2016 May 10.
Artículo en Inglés | MEDLINE | ID: mdl-26855380

RESUMEN

Drugs of long-term use may cause the accumulation of chemical compounds in human body. Therefore, the evaluation and structure characterization of synthesis and degradation impurities is substantial to guarantee drug safety and successful pharmaceutical therapy. The present work evaluated the anticoagulant rivaroxabana (RIV) under stress conditions in order to elucidate the chemical structure of major degradation products (DPs) formed after drug exposition to acid and alkaline hydrolysis, and UVC radiation. Analyses were performed in UPLC coupled to quadrupole time-of-flight MS. ESI was applied in positive mode, and C18 Agilent(®) column (2.1×50 mm, 1.8 µm) used for separation of compounds. RIV molecular íon [M+H](+) (m/z 436.07) was fragmented under 20 kV, best energetic condition to obtain clear and reproducible fragmentation pattern, assisting identification of RIV DPs. With support from UPLC separation and specific detection by MS/MS, three main degradation products (DP-1, DP-2, and DP-3) formed under stress conditions were successfully characterized. Presented study agrees with requirements for analytical assessment of impurities in pharmaceutical formulations, ensuring quality of pharmaceutical substances.


Asunto(s)
Anticoagulantes/química , Rivaroxabán/química , Ácidos/química , Química Farmacéutica/métodos , Cromatografía Líquida de Alta Presión/métodos , Contaminación de Medicamentos , Estabilidad de Medicamentos , Hidrólisis , Espectrometría de Masa por Ionización de Electrospray/métodos , Espectrometría de Masas en Tándem/métodos
19.
Anal Chim Acta ; 905: 51-7, 2016 Jan 28.
Artículo en Inglés | MEDLINE | ID: mdl-26755136

RESUMEN

The use of reference solutions dispersed on filter paper discs is proposed for the first time as an external calibration strategy for matrix matching and determination of As, Cd, Co, Cr, Cu, Mn, Ni, Pb, Sr, V and Zn in plants by laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS). The procedure is based on the use of filter paper discs as support for aqueous reference solutions, which are further evaporated, resulting in solid standards with concentrations up to 250 µg g(-1) of each element. The use of filter paper for calibration is proposed as matrix matched standards due to the similarities of this material with botanical samples, regarding to carbon concentration and its distribution through both matrices. These characteristics allowed the use of (13)C as internal standard (IS) during the analysis by LA-ICP-MS. In this way, parameters as analyte signal normalization with (13)C, carrier gas flow rate, laser energy, spot size, and calibration range were monitored. The calibration procedure using solution deposition on filter paper discs resulted in precision improvement when (13)C was used as IS. The method precision was calculated by the analysis of a certified reference material (CRM) of botanical matrix, considering the RSD obtained for 5 line scans and was lower than 20%. Accuracy of LA-ICP-MS determinations were evaluated by analysis of four CRM pellets of botanical composition, as well as by comparison with results obtained by ICP-MS using solution nebulization after microwave assisted digestion. Plant samples of unknown elemental composition were analyzed by the proposed LA method and good agreement were obtained with results of solution analysis. Limits of detection (LOD) established for LA-ICP-MS were obtained by the ablation of 10 lines on the filter paper disc containing 40 µL of 5% HNO3 (v v(-1)) as calibration blank. Values ranged from 0.05 to 0.81  µg g(-1). Overall, the use of filter paper as support for dried aqueous standards showed to be a useful strategy for calibration and plant analysis by LA-ICP-MS.


Asunto(s)
Papel , Plantas/química , Oligoelementos/análisis , Calibración
20.
Sci Total Environ ; 514: 68-76, 2015 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-25659307

RESUMEN

Herbicides are very effective at eliminating weed and are largely used in rice paddy around the world, playing a fundamental role in maximizing yield. Therefore, considering the flooded environment of rice paddies, it is necessary to understand the side effects on non-target species. Field experiment studies were carried out during two rice growing seasons in order to address how the commonly-used herbicides imazethapyr and imazapic, bispyribac-sodium and penoxsulam, used at recommended dosage, affect water quality and the non-target zooplankton community using outdoor rice field microcosm set-up. The shortest (4.9 days) and longest (12.2 days) herbicide half-life mean, estimated of the dissipation rate (k) is shown for imazethapyr and bispyribac-sodium, respectively. Some water quality parameters (pH, conductivity, hardness, BOD5, boron, potassium, magnesium, phosphorus and chlorides) achieved slightly higher values at the herbicide treatment. Zooplankton community usually quickly recovered from the tested herbicide impact. Generally, herbicides led to an increase of cladocera, copepods and nauplius population, while rotifer population decreased, with recovery at the end of the experiment (88 days after herbicide treatment).


Asunto(s)
Herbicidas/metabolismo , Contaminantes Químicos del Agua/metabolismo , Zooplancton/fisiología , Agricultura , Animales , Benzoatos/análisis , Benzoatos/metabolismo , Biodegradación Ambiental , Herbicidas/análisis , Imidazoles/análisis , Imidazoles/metabolismo , Ácidos Nicotínicos/análisis , Ácidos Nicotínicos/metabolismo , Oryza , Pirimidinas/análisis , Pirimidinas/metabolismo , Sulfonamidas/análisis , Sulfonamidas/metabolismo , Uridina/análogos & derivados , Uridina/análisis , Uridina/metabolismo , Contaminantes Químicos del Agua/análisis
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