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1.
J Oral Maxillofac Surg ; 77(4): 818-827, 2019 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-30395821

RESUMEN

PURPOSE: The objective of this prospective, randomized controlled pilot study of patients undergoing orthognathic surgery was to compare the hospital length of stay (LOS) in patients using intravenous patient-controlled analgesia (PCA) versus patients receiving scheduled and as-needed oral analgesia. PATIENTS AND METHODS: A total of 40 patients (19 male and 21 female patients) aged 16 to 56 years (mean, 20.73 years; standard deviation, 6.87 years) were recruited prospectively and randomized to PCA and non-PCA groups of equal size. Recording of the patient-reported pain score using a visual analog scale was commenced at 8:00 am on day 1 after surgery until discharge. The pain score from routine nursing observations during the postoperative period was recorded until the patient was discharged from the hospital. RESULTS: Randomization resulted in approximately equal proportions of male patients (45% vs 50%) and median ages (18.5 years vs 20 years) for the PCA group versus the non-PCA group; however, the PCA group was noted to have a higher proportion of double-jaw surgery (65% vs 40%). The median LOS was 2 days for both the PCA and non-PCA groups (P = .06). No statistically significant difference in pain scores was found between the 2 groups either at rest (P = .27) or on movement (P = .13). CONCLUSIONS: No evidence was found to indicate the superiority of either the PCA or non-PCA regimen with respect to LOS and pain scores; however, this is not evidence of equivalence of the 2 pain management approaches.


Asunto(s)
Analgesia Controlada por el Paciente , Tiempo de Internación , Procedimientos Quirúrgicos Ortognáticos , Adolescente , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Dolor Postoperatorio/terapia , Proyectos Piloto , Estudios Prospectivos , Adulto Joven
2.
Biol Lett ; 14(8)2018 08.
Artículo en Inglés | MEDLINE | ID: mdl-30111659

RESUMEN

Cadaver decomposition islands around animal carcasses can facilitate establishment of various plant life. Facultative scavengers have great potential for endozoochory, and often aggregate around carcasses. Hence, they may disperse plant seeds that they ingest across the landscape towards cadaver decomposition islands. Here, we demonstrate this novel mechanism along a gradient of wild tundra reindeer carcasses. First, we show that the spatial distribution of scavenger faeces (birds and foxes) was concentrated around carcasses. Second, faeces of the predominant scavengers (corvids) commonly contained viable seeds of crowberry, a keystone species of the alpine tundra with predominantly vegetative reproduction. We suggest that cadaver decomposition islands function as endpoints for directed endozoochory by scavengers. Such a mechanism could be especially beneficial for species that rely on small-scale disturbances in soil and vegetation, such as several Nordic berry-producing species with cryptic generative reproduction.


Asunto(s)
Dispersión de Semillas , Animales , Aves , Ericaceae , Heces , Conducta Alimentaria , Zorros , Noruega , Reno , Semillas
3.
Behav Ecol ; 33(1): 137-146, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35197809

RESUMEN

How and where a female selects an area to settle and breed is of central importance in dispersal and population ecology as it governs range expansion and gene flow. Social structure and organization have been shown to influence settlement decisions, but its importance in the settlement of large, solitary mammals is largely unknown. We investigate how the identity of overlapping conspecifics on the landscape, acquired during the maternal care period, influences the selection of settlement home ranges in a non-territorial, solitary mammal using location data of 56 female brown bears (Ursus arctos). We used a resource selection function to determine whether females' settlement behavior was influenced by the presence of their mother, related females, familiar females, and female population density. Hunting may remove mothers and result in socio-spatial changes before settlement. We compared overlap between settling females and their mother's concurrent or most recent home ranges to examine the settling female's response to the absence or presence of her mother on the landscape. We found that females selected settlement home ranges that overlapped their mother's home range, familiar females, that is, those they had previously overlapped with, and areas with higher density than their natal ranges. However, they did not select areas overlapping related females. We also found that when mothers were removed from the landscape, female offspring selected settlement home ranges with greater overlap of their mother's range, compared with mothers who were alive. Our results suggest that females are acquiring and using information about their social environment when making settlement decisions.

4.
Mov Ecol ; 10(1): 52, 2022 Nov 29.
Artículo en Inglés | MEDLINE | ID: mdl-36447280

RESUMEN

BACKGROUND: The movement extent of mammals is influenced by human-modified areas, which can affect population demographics. Understanding how human infrastructure influences movement at different life stages is important for wildlife management. This is true especially for large carnivores, due to their substantial space requirements and potential for conflict with humans. METHODS: We investigated human impact on movement and habitat selection by GPS-collared male brown bears (Ursus arctos) in two life stages (residents and dispersers) in central Sweden. We identified dispersers visually based on their GPS locations and used hidden Markov models to delineate dispersal events. We used integrated step selection analysis (iSSA) to infer movement and habitat selection at a local scale (availability defined by hourly relocations), and resource selection functions (RSFs) to infer habitat selection at a landscape scale (availability defined by the study area extent). RESULTS: Movement of residents on a local scale was facilitated by small forestry roads as they moved faster and selected areas closer to forestry roads, and they avoided areas closer to larger public roads and buildings on both scales. Dispersers were more ambivalent in their response to human infrastructure. Dispersers increased their speed closer to small forestry roads and larger public roads, did not exhibit selection for or against any road class, and avoided areas closer to buildings only at local scale. Dispersers did not select for any features on the landscape, which is likely explained by the novelty of the landscape or their naivety towards it. CONCLUSION: Our results show that movement in male brown bears is life stage-dependent and indicate that connectivity maps derived from movement data of dispersing animals may provide more numerous and more realistic pathways than those derived from resident animal data alone. This suggests that data from dispersing animals provide more realistic models for reconnecting populations and maintaining connectivity than if data were derived from resident animals alone.

5.
Occup Environ Med ; 68(10): 746-52, 2011 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-21297152

RESUMEN

OBJECTIVES: To measure air pollutant concentrations in Chinese restaurant kitchens using different stove types and assess their influence on workers' respiratory health. METHODS: 393 kitchen workers from 53 Chinese restaurants were surveyed over 16 months: 115 workers from 21 restaurants using only electric stoves and 278 workers from 32 restaurants using only gas stoves. Workers were interviewed about their respiratory symptoms and had their lung function tested. Concentrations of nitric oxide (NO), nitrogen dioxide (NO(2)), carbon monoxide (CO), carbon dioxide (CO(2)), methane (CH(4)), non-methane hydrocarbons (NMHC), total volatile organic compounds (TVOC) and fine particulate matter (PM(2.5)) were measured using portable monitors and air-bag sampling. Temperature and noise levels were assessed. RESULTS: Median concentrations of NO, NO(2) and CO were 7.4, 1.5 and 1.6 times higher in gas-fuelled kitchens than in electric ones and average concentrations of PM(2.5) and TVOC were 81% and 78% higher, respectively. Differences were smaller for CH(4) and NMHC. Electricity-run kitchens were 4.5°C cooler and 9 dBA less noisy than gas-fuelled ones. Workers using electric cookers had significantly better lung function than their gas-using counterparts and their mean FEV(1) and FVC values were 5.4% and 3.8% higher, respectively, after adjustment for confounders. Wheeze, phlegm, cough and sore throat were more prevalent in workers using gas. The adjusted OR for having phlegm regularly was significantly higher. CONCLUSIONS: The poorer lung function and higher prevalence of respiratory symptoms among workers in gas-fuelled kitchens compared to those in electricity-powered kitchens may be associated with exposure to higher concentrations of toxic air pollutants generated during gas cooking.


Asunto(s)
Contaminantes Ocupacionales del Aire/análisis , Contaminación del Aire Interior/análisis , Enfermedades Pulmonares/epidemiología , Exposición Profesional/análisis , Material Particulado/análisis , Adulto , Contaminantes Ocupacionales del Aire/efectos adversos , Contaminantes Ocupacionales del Aire/toxicidad , Contaminación del Aire Interior/efectos adversos , Pueblo Asiatico/etnología , Culinaria , Volumen Espiratorio Forzado , Hong Kong/epidemiología , Artículos Domésticos , Humanos , Ruido en el Ambiente de Trabajo , Material Particulado/toxicidad , Pruebas de Función Respiratoria , Restaurantes , Temperatura , Capacidad Vital
6.
Guang Pu Xue Yu Guang Pu Fen Xi ; 31(1): 154-7, 2011 Jan.
Artículo en Zh | MEDLINE | ID: mdl-21428078

RESUMEN

In order to screen and identify the source of spilled oils at sea, synchronous fluorescence scans combined with clustering analysis are proposed and applied to different crude oil and weathering crude oil. SFS data of deltal = 25 nm were recorded and dealt with clustering analysis. The cluster results of SFS data in the range of 300 - 500 nm show that the crude oil and the weathering oil could separate completely. And the crude oils from different sea areas, also collected at different time, clustered into different groups, respectively. The results indicate that this method could preliminarily selected, and maybe serves as an assistant method in oil spill identification.


Asunto(s)
Contaminación por Petróleo/análisis , Petróleo/análisis , Espectrometría de Fluorescencia/métodos , Océanos y Mares
7.
Head Neck Pathol ; 15(3): 945-949, 2021 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-33544378

RESUMEN

Canalicular adenoma (CAD) is an uncommon benign tumor of minor salivary glands with predilection for the upper labial mucosa. An 80-year-old female presented with nine submucosal nodules of the upper labial mucosa and bilateral buccal mucosa. Histopathologic examination revealed multifocal circumscribed tumor islands with a tubular growth pattern within a loose hypocellular myxoid background stroma. Interconnecting rows of columnar tumor cells imparted a canalicular morphology. In addition to the characteristic histopathologic findings, a comprehensive immunohistochemical panel supported a final diagnosis of multifocal CAD. Synchronous multifocality in CAD is an infrequent finding and this sine qua non clinicopathologic correlation article exemplifies such a case.


Asunto(s)
Adenoma/patología , Mucosa Bucal/patología , Neoplasias de las Glándulas Salivales/patología , Anciano de 80 o más Años , Femenino , Humanos
8.
BMJ Case Rep ; 14(9)2021 Sep 20.
Artículo en Inglés | MEDLINE | ID: mdl-34544699

RESUMEN

Granular cell tumour (GCT) is a rare soft tissue lesion which many consider to have malignant potential of yet unknown aetiopathogenesis. Oral GCT lesions may occur in an area of leucoplakia and are predominantly present on the tongue. This case study highlights an uncommon presentation of this condition located on the buccal mucosa and illustrates the need for meticulous evaluation of suspicious lesions. Due to the malignant risk associated with GCT lesions, it is important to make the correct diagnosis and ensure complete surgical excision for these cases. Ongoing long-term follow-up is also indicated to monitor for recurrence or malignancy.


Asunto(s)
Tumor de Células Granulares , Neoplasias de la Lengua , Tumor de Células Granulares/diagnóstico por imagen , Tumor de Células Granulares/cirugía , Humanos , Mucosa Bucal , Recurrencia Local de Neoplasia , Lengua
9.
Water Sci Technol ; 61(6): 1499-503, 2010.
Artículo en Inglés | MEDLINE | ID: mdl-20351429

RESUMEN

The dual objectives of this study are to: (1) examine the relationship between COD and BOD in seawater environment with a rapid but reliable method for the measurement of BOD in seawater, and (2) establish the relationship model between BOD(5) and COD in the firth of Dongbao River to predict the values of BOD(5). The first objective is met by the successful development of a technique utilizing bacteria-immobilized membrane flow cell for biodegradation process, coupled with fibre optic fluorescence detection for oxygen depletion quantitation. The technique has been applied to coastal seawater samples collected in the coastal area of Shenzhen, China. The BOD(5) and COD values for the samples are acquired and the results show that there is no apparent linear relationship existing between BOD(5) and COD in relatively clean seawater samples away from the shore. However, in estuary water samples containing relatively high concentration of sewage contamination, a linear correlation does exist between BOD(5) and COD. The linear relationship between the two parameters allows for the calculation of BOD(5) values based on COD data which can be measured more readily and precisely.


Asunto(s)
Ecosistema , Oxígeno/metabolismo , Agua de Mar/química , China , Océanos y Mares , Oxígeno/química , Ríos , Contaminación del Agua
10.
R Soc Open Sci ; 7(6): 191644, 2020 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-32742677

RESUMEN

Animal carcasses provide an ephemeral pulse of nutrients for scavengers that use them. Carcass sites can increase species interactions and/or ephemeral, localized landscapes of fear for prey within the vicinity. Few studies have applied the landscape of fear to carcasses. Here, we use a mass die-off of reindeer caused by lightning in Norway to test whether rodents avoided larger scavengers (e.g. corvids and fox). We used the presence and abundance of faeces as a proxy for carcass use over the course of 2 years and found that rodents showed the strongest avoidance towards changes in raven abundance (ß = -0.469, s.e. = 0.231, p-value = 0.0429), but not fox, presumably due to greater predation risk imposed by large droves of raven. Moreover, the emergence of rodent occurrence within the carcass area corresponded well with the disappearance of raven during the second year of the study. We suggest that carcasses have the potential to shape the landscape of fear for prey, but that the overall effects of carcasses on individual fitness and populations of species ultimately depend on the carcass regime, e.g. carcass size, count, and areal extent, frequency and the scavenger guild. We discuss conservation implications and how carcass provisioning and landscapes of fear could be potentially used to manage populations and ecosystems, but that there is a gap in understanding that must first be bridged.

11.
Water Sci Technol ; 60(12): 3219-23, 2009.
Artículo en Inglés | MEDLINE | ID: mdl-19955646

RESUMEN

The dual objectives of this study are to: (1) examine the relationship between COD and BOD in seawater environment with a rapid but reliable method for the measurement of BOD in seawater, and (2) establish the relationship model between BOD(5) and COD in the firth of Dongbao River to predict the values of BOD(5). The first objective is met by the successful development of a technique utilizing bacteria-immobilized membrane flow cell for biodegradation process, coupled with fibre optic fluorescence detection for oxygen depletion quantitation. The technique has been applied to coastal seawater samples collected in the coastal area of Shenzhen, China. The BOD(5) and COD values for the samples are acquired and the results show that there is no apparent linear relationship existing between BOD(5) and COD in relatively clean seawater samples away from the shore. However, in estuary water samples containing relatively high concentration of sewage contamination, a linear correlation does exist between BOD(5) and COD. The linear relationship between the two parameters allows for the calculation of BOD(5) values based on COD data which can be measured more readily and precisely.


Asunto(s)
Técnicas de Química Analítica/métodos , Oxígeno/análisis , Agua de Mar/análisis , China , Modelos Lineales , Cómputos Matemáticos , Océanos y Mares , Agua de Mar/química , Agua de Mar/microbiología , Factores de Tiempo , Contaminación del Agua/análisis , Contaminación del Agua/estadística & datos numéricos
12.
J Am Soc Mass Spectrom ; 19(10): 1568-75, 2008 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-18657993

RESUMEN

Enhanced anticoagulation and/or even bleeding are often observed when patients on long-term warfarin (WAR) therapy consumed Danshen, a well-known medicinal herb in traditional Chinese medicine (TCM). This study demonstrates that altered WAR metabolism, arising from its interaction with the active components in Danshen, played a significant role in this curative effect. Mass spectrometric techniques including ESI-ITMS (electrospray ionization ion-trap mass spectrometry) and ESI-TOF (time-of-flight)-MS have been developed for the study of such drug-herb interactions. The experimental approach involved a detailed analysis and comparison of WAR metabolites in vivo from blood or urine of rats that had been orally administrated with WAR, either singly or together with the representative bioactive component of Danshen-lipid soluble TIIA (Tanshinon IIA), and a study of the interaction of human serum albumin (HSA), WAR, and water-soluble sodium tanshinone IIA sulfonate (STS) in vitro. Results demonstrate that TIIA accelerates the metabolic rate of WAR, whereas STS displaces WAR from the WAR-HSA complex, resulting in an increase of free WAR concentration in blood. It is suggested that the elevated level and enhanced metabolism of WAR is responsible for the over-anticoagulation effect observed.


Asunto(s)
Fenantrenos/farmacología , Albúmina Sérica/metabolismo , Espectrometría de Masa por Ionización de Electrospray/métodos , Warfarina/metabolismo , Abietanos , Animales , Unión Competitiva/efectos de los fármacos , Medicamentos Herbarios Chinos/farmacología , Interacciones de Hierba-Droga , Humanos , Masculino , Unión Proteica/efectos de los fármacos , Ratas , Ratas Sprague-Dawley , Warfarina/administración & dosificación , Warfarina/farmacocinética
13.
Chemosphere ; 68(1): 126-39, 2007 May.
Artículo en Inglés | MEDLINE | ID: mdl-17291564

RESUMEN

The extent of organochlorine pesticides (OCPs) contamination in coastal waters around LaiZhou Bay and JiaoZhou Bay in Shandong Peninsula, northern China, was investigated. The areas around the two bays are both densely populated, thrive with intensive agriculture and industrial activities. Multi-techniques including GC-MS, GC-muECD coupled with chemical peak confirmation and strict QC procedures were used for the quantitative determination of 15 OCPs including alpha, beta, gamma and delta isomers of hexachlorocyclohexane (HCH), pentachloronitrobenzene (PCNB), heptachlor, aldrin, endosulfan, p,p'-DDE, dieldrin, endrin, p,p'-DDD, o,p'-DDT, p,p'-DDT and methoxychlor. The survey results show that contaminations by OCP residues remain widespread in the areas, but the averaged concentration levels are all below the regulatory limits, e.g., CMC limits (acute criterion values) specified in US Environmental Protection Agency (USEPA) and China national standards. Average concentration of OCPs in water samples were from undetectable to 3.8 ng l(-1) in LaiZhou Bay and from 0.1 to 3.9 ng l(-1) in JiaoZhou Bay, respectively. A comparison between the current and historical data shows a rapidly decreasing trend of OCPs over the past twenty years in the study areas.


Asunto(s)
Hidrocarburos Clorados/análisis , Residuos de Plaguicidas/análisis , Agua de Mar/química , Contaminantes Químicos del Agua/análisis , China , Cromatografía de Gases y Espectrometría de Masas/métodos
14.
Guang Pu Xue Yu Guang Pu Fen Xi ; 27(10): 2083-7, 2007 Oct.
Artículo en Zh | MEDLINE | ID: mdl-18306801

RESUMEN

Chromophoric dissolved organic matter (CDOM) represents the fraction of the dissolved organic pool which absorbs light in the visible as well as UV ranges. It could affect the color of the waters. It is necessary to study it during in research on ecosystem, remote sensing of the water color and the cycle of carbon in waters. CDOM can fluoresce when excited, so fluorescence spectrum has been used to study its origin, distribution, and change. In the present article the fluorescence spectrophotometer was used to study the relation between the fluorescence intensity, spectrum area and the concentration of CDOM. When the concentration of CDOM is low (less than 75 mg x L(-1)), there is a better linear relationship (r2 > 0.98) between the fluorescence intensity, the spectrum area and the concentration of CDOM. Meanwhile good linear relations were found between the fluorescence intensity and spectrum area, which showed the same changeable trend of the fluorescence intensity and spectrum area with the concentration change of CDOM. A method was established to quantify the concentration of CDOM in water from different source using the linear relationship between the spectrum area and the concentration. It suits the complicated constituent analysis of CDOM and could really and accurately show the concentration of CDOM in natural water.


Asunto(s)
Agua Dulce/química , Compuestos Orgánicos/análisis , Agua de Mar/química , Espectrometría de Fluorescencia/métodos , Contaminantes Químicos del Agua/análisis , Monitoreo del Ambiente
15.
Guang Pu Xue Yu Guang Pu Fen Xi ; 27(10): 2107-10, 2007 Oct.
Artículo en Zh | MEDLINE | ID: mdl-18306806

RESUMEN

In the present article the principle and advantages of the method to build classification model by partial least squares are briefly introduced. The method was applied to deal with the seawater data obtained from the primary polluted sea area of Jiaozhou bay and Laizhou bay by GC-MS. The classification models have been built for seawater samples from different contaminated areas. The results indicate that PLS is very suitable for dealing with the problems with the data sets that contain many variables and few samples and have serious co-linearity. Accurate classification models can be built by use of PLS to get the classification information of pollution sources from two or many kinds of polluted seawaters data sets from GCC-MS. The cross validation relativities of the model comes to over 0. 91. This result is approving, which can provide a reliable foundation for distinguishing pollution sources correctly. Moreover, compared with the traditional method, the classification figures constructed by model' s yi in the article are more clear and intuitive, and can express the model's discrimination effect better.


Asunto(s)
Contaminación Ambiental , Agua de Mar/análisis , Contaminantes del Agua/análisis , Monitoreo del Ambiente , Cromatografía de Gases y Espectrometría de Masas , Análisis de los Mínimos Cuadrados
16.
Sci Rep ; 7: 45222, 2017 03 23.
Artículo en Inglés | MEDLINE | ID: mdl-28332613

RESUMEN

Harvest can affect the ecology and evolution of wild species. The removal of key individuals, such as matriarchs or dominant males, can disrupt social structure and exacerbate the impact of hunting on population growth. We do not know, however, how and when the spatiotemporal reorganization takes place after removal and if such changes can be the mechanism that explain a decrease in population growth. Detailed behavioral information from individually monitored brown bears, in a population where hunting increases sexually selected infanticide, revealed that adult males increased their use of home ranges of hunter-killed neighbors in the second year after their death. Use of a hunter-killed male's home range was influenced by the survivor's as well as the hunter-killed male's age, population density, and hunting intensity. Our results emphasize that hunting can have long-term indirect effects which can affect population viability.


Asunto(s)
Conducta Animal , Conservación de los Recursos Naturales , Ursidae/fisiología , Distribución Animal , Animales , Femenino , Humanos , Longevidad , Masculino , Deportes
17.
Chemosphere ; 186: 438-445, 2017 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-28806671

RESUMEN

PM2.5 samples were collected at six indoor public places that contained dedicated smoking lounges. Samples were taken in the smoking lounges, at two indoor locations outside of the lounges, and in outdoor air near the venues. Organic carbon (OC), elemental carbon (EC), and non-polar organic compounds including polycyclic aromatic hydrocarbons (PAHs), n-alkanes (n-C16 to n-C40), iso/anteiso-alkanes (C29 to C33), hopanes and phthalate esters (PAEs) were quantified. Average PM2.5 levels of 170.2 ± 85.9 µg/m3 in the lounges exceeded limits of 25 µg/m3 set by World Health Organization (WHO); these levels were 5.4 and 3.9 times higher than those indoors and outdoors, respectively. High ratios of OC to PM2.5, OC to EC, and PAHs diagnostic ratios in the lounges indicated contributions from environmental tobacco smoke (ETS). The maximum carbon number (Cmax) and carbon preference indices (CPI) for n-alkanes showed ETS transport from the enclosed lounges to nearby indoor non-smoking areas. Iso/anteiso-alkanes in the lounges were 876.5 ng/m3, ∼80 times higher than outdoor levels. 17α(H)-21ß(H),30-norhopane and 17α(H)-21ß(H),(22R)-homohopane were much higher in the lounges than outdoor air, but they cannot be directly attributed to ETS. Estimated carcinogenic risks of PAHs in the lounges exceeded the acceptable level of 10- 6.


Asunto(s)
Contaminantes Atmosféricos/análisis , Contaminación del Aire Interior/análisis , Monitoreo del Ambiente/métodos , Material Particulado/análisis , Hidrocarburos Policíclicos Aromáticos/análisis , Contaminantes Atmosféricos/efectos adversos , Contaminación del Aire Interior/efectos adversos , Alcanos/análisis , Carbono/análisis , China , Humanos , Tamaño de la Partícula , Material Particulado/efectos adversos , Ácidos Ftálicos/análisis , Hidrocarburos Policíclicos Aromáticos/efectos adversos , Medición de Riesgo , Contaminación por Humo de Tabaco/efectos adversos , Contaminación por Humo de Tabaco/análisis
18.
J Chromatogr A ; 1137(2): 180-7, 2006 Dec 29.
Artículo en Inglés | MEDLINE | ID: mdl-17126847

RESUMEN

The biodegradation of the organophosphorus insecticide methyl parathion (MP) in aqueous environment by bacteria isolated from river sediment has been studied. Two species of bacteria which show strong MP degradation ability are identified as Shewanella and Vibrio parahaemolyticus. The biodegradation of MP proceeded rapidly with the formation of a series of intermediate products, which were analyzed using a combination of GC/MS and HPLC/ESI-TOFMS techniques. The major products tentatively identified include a series of reduced products of MP. Results demonstrate that the coupling of TOFMS to HPLC enhances further the capability of LC-MS in the identification of polar organic species in complex environmental samples. Degradation pathways leading to the formation of these products are proposed which involves first the reduction of nitro to amino group in MP, followed by combination with some intrinsic matters of bacteria. The mechanism and products from biodegradation are quite different from those of photocatalytic process for which the main intermediates included methyl paraoxon and 4-nitrophenol.


Asunto(s)
Cromatografía Liquida/métodos , Cromatografía de Gases y Espectrometría de Masas/métodos , Metil Paratión/metabolismo , Shewanella/metabolismo , Espectrometría de Masa por Ionización de Electrospray/métodos , Vibrio parahaemolyticus/metabolismo , Biotransformación , Redes y Vías Metabólicas , Metil Paratión/análisis , Contaminantes Químicos del Agua/análisis
19.
J Chromatogr A ; 1089(1-2): 18-24, 2005 Sep 30.
Artículo en Inglés | MEDLINE | ID: mdl-16130766

RESUMEN

Glycyrrhizic acid (GA) and licorice flavonoids (LF) are the two classes of bioactive components in licorice with known pharmacological effects. But long-term excessive intake of GA may cause sodium retention and hypertension. In this study, the performance and adsorption characteristics of four widely used macroporous resins for the separation of deglycyrrhizinated, flavonoids enriched licorice has been critically evaluated. The sorption and desorption properties of LF and GA on macroporous resins including XDA-1, LSA-10, D101 and LSA-20 have been compared. The adsorption capacity was found to depend strongly on the pH of the feed solution. XDA-1 offers much higher adsorption capacity for GA and LF than other resins, and its adsorption data fit the best to the Freundlich isotherm. XDA-1 also shows much higher adsorption affinity towards LF than that of GA based on calculated results from the measured adsorption isotherms. Dynamic adsorption and desorption experiments have been carried out on a XDA-1 resin packed column to obtain optimal parameters for separating GA and LF. An enriched LF extract (about 21.9% purity) free of GA, and an enriched GA extract with 66% purity can be separated from crude licorice extract in one run.


Asunto(s)
Cromatografía Líquida de Alta Presión/métodos , Flavonoides/aislamiento & purificación , Ácido Glicirrínico/aislamiento & purificación , Resinas Sintéticas/química , Adsorción , Concentración de Iones de Hidrógeno , Cinética , Termodinámica
20.
J Agric Food Chem ; 53(19): 7408-14, 2005 Sep 21.
Artículo en Inglés | MEDLINE | ID: mdl-16159166

RESUMEN

Five different flavonoids were isolated from licorice after multistep chromatographic fractionation. The aim was to identify and characterize active components in licorice responsible for antibrowning activities and to seek new tyrosinase inhibitors for applications as antibrowning and depigmenting agents in the food and cosmetic industries. The isolated flavonoids were identified as liquiritin, licuraside, isoliquiritin, liquiritigenin (from Glycyrrhiza uralensis Fisch.), and licochalcone A (from Glycyrrhiza inflate Bat.) by UV, MS, (1)H NMR, and (13)C NMR analyses. The inhibitory potencies and capacities of these flavonoids toward monophenolase activity of mushroom tyrosinase were investigated. The IC(50) values of licuraside, isoliquiritin, and licochalcone A for monophenolase activity were 0.072, 0.038, and 0.0258 mM, respectively. A study of the mechanisms of monophenolase inhibition by these flavonoids indicated that they are all competitive inhibitors. Different from the above flavonoids, no inhibitory activity was observed for liquiritin, whereas liquiritigenin activated the monophenolase activity as a cofactor. The inhibitory effect of licuraside, isoliquiritin, and licochalcone A on diphenolase activity with l-DOPA as the substrate was much lower than those with l-tyrosine. Results suggest that licuraside, isoliquiritin, and licochalcone A have the high potential to be further developed into effective antibrowning and depigmenting agents.


Asunto(s)
Flavonoides/análisis , Flavonoides/aislamiento & purificación , Glycyrrhiza/química , Monofenol Monooxigenasa/metabolismo , Péptidos/farmacología , Agaricales/enzimología , Flavonoides/farmacología , Espectroscopía de Resonancia Magnética , Oxidorreductasas/antagonistas & inhibidores , Oxidorreductasas/metabolismo
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