Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 8 de 8
Filtrar
Más filtros










Intervalo de año de publicación
1.
Environ Pollut ; 174: 16-27, 2013 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-23246622

RESUMEN

Pipeline systems used to transport petroleum products represent a potential source of soil pollution worldwide. The design of new techniques that may improve current monitoring of pipeline leakage is imperative. This paper assesses the remote detection of small leakages of liquid hydrocarbons indirectly, through the analysis of spectral features of contaminated plants. Leaf and canopy spectra of healthy plants were compared to spectra of plants contaminated with diesel and gasoline, at increasing rates of soil contamination. Contamination effects were observed both visually in the field and thorough changes in the spectral reflectance patterns of vegetation. Results indicate that the remote detection of small volumes of gasoline and diesel contaminations is feasible based on the red edge analysis of leaf and canopy spectra of plants. Brachiaria grass ranks as a favourable choice to be used as an indicator of HCs leakages along pipelines.


Asunto(s)
Monitoreo del Ambiente/métodos , Gasolina/análisis , Plantas/química , Tecnología de Sensores Remotos/métodos , Contaminantes del Suelo/análisis , Contaminantes del Suelo/química
2.
Rev. bras. plantas med ; 15(4): 583-588, 2013. graf, tab
Artículo en Inglés | LILACS | ID: lil-695244

RESUMEN

Volatile oils from leaves and flowers of Aloysia gratissima were investigated for their chemical composition and antimicrobial activity against the bacteria Bacilus subtilis, Staphylococcus aureus, Salmonella choleraesuis, Pseudomonas aeruginosa, Streptococcus pneumoniae and the Candida albicans yeast. The minimum inhibitory concentrations (MIC) of the oils were determined by the micro-dilution method, while the chemical composition was determined by GC-MS (gas chromatography mass spectrometry). The fresh leaves and inflorescence were subjected to hydrodistillation for 120 min using a Clevenger-type apparatus, and the essential oil was tested against microorganisms. High concentrations of sesquiterpenes were observed for the inflorescence, and monoterpenes were observed for the leaves. The main compounds of the inflorescence essential oil were E-caryophyllene, germacrene B, guaiol and bulnesol, while in the leaves the main compounds were trans-pinocamphone, trans-pinocarveyl acetate, and guaiol. The essential oil from the leaves showed an effect against P. aeruginosa and S. pneumonia, and the essential oil of the inflorescence showed an effect against P. aeruginosa, S. pneumonia, and Candida albicans.


O óleo essencial de folhas e de flores de Aloysia gratissima foi avaliado quanto à composição química e ação antimicrobiana contra as bactérias Bacilus subtilis, Staphylococcus aureus, Salmonella choleraesuis, Pseudomonas aeruginosa, Streptococcus pneumoniae, e a levedura Candida albicans. A concentração mínima inibitória (MIC) dos óleos essenciais foi determinada pelo método da microdiluição e a composição química determinada por CG-EM (Cromatografia Gasosa acoplada a Espectrômetro de Massas). Folhas e inflorescências frescas foram hidrodestiladas por 120 minutos em aparelho Clevenger sendo o óleo essencial testado contra microorganismos. Para as flores foi observada maior concentração de sesquiterpenos, enquanto que as folhas apresentaram maior concentração de monoterpenos. Os principais constituintes do óleo essencial da flor foram: E-cariofileno, germacreno B, guaiol e bulnesol; e das folhas foram: trans-pinocamfona, acetato de trans-pinocarveol e guaiol. O óleo essencial da folha mostrou atividade contra P. aeruginosa e S. pneumoniae, e o óleo essencial da flor mostrou atividade contra P. aeruginosa, S. pneumoniae e Candida albicans.


Asunto(s)
Aceites Volátiles/síntesis química , Hojas de la Planta/clasificación , Verbenaceae/clasificación , Plantas Medicinales/clasificación , Cromatografía de Gases , Antiinfecciosos/análisis
3.
Int J Sports Med ; 33(3): 211-7, 2012 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-22161295

RESUMEN

The aging process may impair exercise tolerance in the heat. It is not clear whether this impairment is partly due to a reduction in aerobic capacity. To compare the exercise performance and thermoregulatory responses of middle-aged and young adults with similar aerobic capacities and training statuses, 7 middle-aged (54±2 years; 58±4 ml·kg - 1·min - 1) and 7 young (28±1 years; 61±5 ml·kg - 1·min - 1) male competitive endurance runners underwent 2 10-km self-paced and 2 fixed-workload (90% of race speed) runs until fatigue on a treadmill in hot (40°C) and moderate (20°C) environments on separate days. The runners' total time, average speed, rectal temperature, heat storage rate, physiological strain index, sweat rate, sweat sensitivity, number of heat-activated sweat glands and sweat rate per sweat gland were measured or calculated. Body fat, body surface area, body surface area per body mass, training volume and VO2max were similar between the 2 groups. No differences were observed in total time (59±3; 49±3; 27±2; 54±5 min in the middle-aged and 60±2; 49±3; 27±2; 51±4 min in the young group), average speed, rectal temperature, heat storage rate, physiological strain index, sweat rate (17±7; 15±3; 23±7; 13±2 g.m - 2.min - 1 in the middle-aged and 20±5; 14±4; 22±5; 15±4 g.m - 2.min - 1 in the young group) or sweat sensitivity between age groups (p>0.05) in any trial. The number of heat-activated sweat glands (88±14; 80±18; 90±16; 66±14 cm - 2 in the middle-aged and 43±10; 32±10; 37±11; 31±11 cm - 2 in the young group) was higher, and the sweat rate per sweat gland was smaller, in the middle-aged than the young group (p<0.05) in all of the trials. We conclude that running performance and body thermoregulation are similar between young and middle-aged runners with similar aerobic capacities and training statuses under hot and moderate conditions in self-paced and fixed-intensity runs. The decrease observed in the sweat rate per sweat gland in middle-aged men was compensated for by a higher number of heat-activated sweat glands.


Asunto(s)
Rendimiento Atlético/fisiología , Calor , Resistencia Física/fisiología , Carrera/fisiología , Adulto , Factores de Edad , Temperatura Corporal , Prueba de Esfuerzo , Humanos , Masculino , Persona de Mediana Edad , Sudoración , Factores de Tiempo
4.
Neotrop Entomol ; 41(1): 2-8, 2012 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-23950002

RESUMEN

The tropane alkaloid (TA) scopolamine is suggested to protect Brugmansia suaveolens (Solanaceae) against herbivorous insects. To test this prediction in a natural environment, scopolamine was induced by methyl jasmonate (MJ) in potted plants which were left 10 days in the field. MJ-treated plants increased their scopolamine concentration in leaves and herbivory decreased. These findings suggest a cause-effect relationship. However, experiments in laboratory showed that scopolamine affect differently the performance of the specialist larvae of the ithomiine butterfly Placidina euryanassa (C. Felder & R. Felder) and the generalist fall armyworm Spodoptera frugiperda (J. E. Smith): the specialist that sequester this TA from B. suaveolens leaves was not negatively affected, but the generalist was. Therefore, scopolamine probably acts only against insects that are not adapted to TAs. Other compounds that are MJ elicited may also play a role in plant resistance against herbivory by generalist and specialist insects, and deserve future investigations.


Asunto(s)
Acetatos/farmacología , Ciclopentanos/farmacología , Herbivoria , Insectos , Oxilipinas/farmacología , Escopolamina , Solanaceae/efectos de los fármacos , Solanaceae/metabolismo , Animales
6.
Braz J Med Biol Res ; 28(6): 705-9, 1995 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-8547856

RESUMEN

Stimulant properties during exercise have been attributed to caffeine (CAF) and tryptophan (Trp). The purpose of the present study was to investigate the effects of CAF and Trp ingestion on rectal temperature (Tre), total exercise time (TET), oxygen consumption (VO2), carbon dioxide production (VCO2), pulmonary ventilation (VE), heart rate (HR) and rate of perceived exertion (RPE) during exercise on a cycle ergometer at 80% of maximal work load, in eight healthy male volunteers. Each subject abstained from caffeine for 48 h and from animal-derived foods for 36 h before each experiment. Aerobic capacity was determined on the first day. In consecutive trials, conducted in a double-blind, randomized, crossed-over manner, each subject received capsules containing CAF (10 mg/kg), Trp (1.2 g), a combination of the two (CAF+Trp), and lactose (PLA), 1 h before exercise. Plasma CAF concentration (PC) was measured by high performance liquid chromatography (HPLC), before (basal concentration) and 1 and 2 h after ingestion of the capsules. At both times after CAF or CAF+Trp ingestion, the PC was elevated compared with the basal concentration (P < 0.05). During exercise, significant increases occurred with time in Tre, TET, VO2, VCO2, VE, HR and RPE (P < 0.01) while no significant difference was observed when CAF or CAF+Trp were compared with control values. Under the conditions of this study, CAF and/or Trp did not affect the physiological parameters measured before, during or after exercise at 80% of maximal work load.


Asunto(s)
Temperatura Corporal/efectos de los fármacos , Cafeína/farmacología , Estimulantes del Sistema Nervioso Central/farmacología , Ejercicio Físico/fisiología , Frecuencia Cardíaca/efectos de los fármacos , Consumo de Oxígeno/efectos de los fármacos , Esfuerzo Físico/efectos de los fármacos , Triptófano/farmacología , Adulto , Estudios Cruzados , Método Doble Ciego , Humanos , Masculino
7.
Braz. j. med. biol. res ; 28(6): 705-9, Jun. 1995. tab
Artículo en Inglés | LILACS | ID: lil-154942

RESUMEN

Stimulant properties during exercise have been attributed to cafeine (CAF) and tryptophan (Trp). The purpose of the present study was to investigate the effects of CAF and Trp ingestion on rectal temperature (Tre), total exercise time (TET), oxygen consumption (VO2), carbon dioxide production (VCO2) pulmunary ventilation (VE), heart rate (HR) and rate of perceived exertion (RPE) during exercise on a cycle ergometer at 80 percent of maximal work load, in eight halthy male volunteers. Each subject abstained from caffeine for 48 h and from animal-derived foods for 36 h before each experiment. Aerobic capacity was determined on the first day. In consecutive trials, conducted in a double-blind, randomized, crossed-over manner, each subject recived capsules containing CAF (10mg/Kg), Trp (1.2g), a combination of the two (CAF + TRP), and lactose (PLA), 1 h before exercise. Plasma CAF concentration (PC) was measured by high performance liquid chromatography (HPLC), before (basal concentration) and 1 and 2 h after ingestion of the capsules. At both times after CAF or CAF + Trp ingestion, the PC was elevated compared with the basal concentration (P < 0.05). During exercise, significant increases occured with time in Tre, TET, VO2, VCO2, VE, HR and RPE (P < 0.01) while no significant difference was observed when CAF or CAF+ Trp were compared with control values. Under the conditions of this study, CAF and/or Trp did not affect the physiological parameters measured before, during or after exercise at 80 percent of maximal work load


Asunto(s)
Humanos , Masculino , Adulto , Temperatura Corporal/efectos de los fármacos , Cafeína/administración & dosificación , Consumo de Oxígeno , Ejercicio Físico/fisiología , Frecuencia Cardíaca , Triptófano/administración & dosificación
8.
Rev. microbiol ; 15(2): 94-102, 1984.
Artículo en Inglés | LILACS | ID: lil-23554

RESUMEN

Em um estudo para determinacao da qualidade bacteriologica do Rio Atibaia Sao Paulo Brasil, desenvolvido durante o periodo de agosto de 1977 a julho de 1978, foi utilizada a relacao coliformes fecais-estreptococos fecais (CF/EF), para a caracterizacao da origem da poluicao fecal.A determinacao quantitativa de coliformes fecais e estreptococos fecais foi efetuada pela tecnica de tubos multiplos, segundo descricao no Standard Methods for the Examination of Water and Wastewater, 14a. ed. A aplicacao da relacao CF/EF permitiu caracterizar como sendo predominantemente humana a origem da contaminacao fecal ao longo do rio, embora se tenha verificado a possivel influencia de lancamentos de efluentes industriais e da distancia dos lancamentos de esgoto na caracterizacao da origem da populacao fecal em alguns pontos do rio


Asunto(s)
Streptococcus , Enterobacteriaceae , Microbiología del Agua , Brasil
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...