Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 7 de 7
Filtrar
Más filtros











Intervalo de año de publicación
1.
Rev Sci Instrum ; 95(8)2024 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-39162605

RESUMEN

We describe a beamline where few-femtosecond ultraviolet (UV) pulses are generated and synchronized to few-cycle near-infrared (NIR) and extreme ultraviolet (XUV) attosecond pulses. The UV light is obtained via third-harmonic generation in argon or neon gas when focusing a phase-stabilized NIR driving field inside a glass cell that was designed to support high pressures for enhanced conversion efficiency. A recirculation system allows reducing the large gas consumption required for the nonlinear process. Isolated attosecond pulses are generated using the polarization gating technique, and the photon spectrometer employed to characterize the XUV radiation consists of a new design based on the combination of a spherical varied-line-space grating and a cylindrical mirror. This design allows for compactness while providing a long entrance arm for integrating different experimental chambers. The entire interferometer is built under vacuum to prevent both absorption of the XUV light and dispersion of the UV pulses, and it is actively stabilized to ensure an attosecond delay stability during experiments. This table-top source has been realized with the aim of investigating UV-induced electron dynamics in neutral states of bio-relevant molecules, but it also offers the possibility to implement a manifold of novel time-resolved experiments based on photo-ionization/excitation of gaseous and liquid targets by ultraviolet radiation. UV pump-XUV probe measurements in ethyl-iodide showcase the capabilities of the attosecond beamline.

2.
Arq. neuropsiquiatr ; 69(2b): 371-376, 2011. ilus, tab
Artículo en Inglés | LILACS | ID: lil-588100

RESUMEN

OBJECTIVE: To assess health-related quality of life (HRQoL) among adults with stroke sequelae and to identify the factors that influenced the domains of HRQoL. METHOD: The subjects were adults with stroke who were admitted to a rehabilitation program between March and August 2008. They were investigated using the following instruments: Medical Outcomes 36-Item Short-Form Health Survey (SF-36), Functional Independence Measure (FIM) and Beck Depression Inventory (BDI). Sixty-four adults of mean age 58.8 years were evaluated. RESULTS: The individuals who had had their injuries for longer times and who were more independent and younger had better HRQoL regarding physical functioning. Social participation was associated with better HRQoL, and there was a difference between groups with and without depressive symptoms. CONCLUSION: HRQoL was compromised primarily with regard to functional characteristics. Moreover, the presence of depressive symptoms contributed towards a decline in HRQoL. Rehabilitation needs to focus on improving functionality and social participation, which may stimulate reductions in depressive symptoms and improvement of HRQoL.


OBJETIVO: Avaliar a qualidade de vida relacionada à saúde (QVRS) de adultos com sequelas de acidente vascular cerebral (AVC) e identificar os fatores que influenciam os domínios da QVRS. MÉTODO: Adultos com AVC admitidos para programa de reabilitação de março a agosto de 2008, investigados com os seguintes instrumentos: SF-36, Medida de Independência Funcional e Inventário de Depressão de Beck. Foram estudados 64 adultos, média de idade de 58,8 anos. RESULTADOS: Os indivíduos com maior tempo de lesão, mais independentes e jovens tiveram melhor QVRS na capacidade funcional. Participação social foi associada com melhor QVRS, e houve diferença entre os grupos com e sem sintomas depressivos. CONCLUSÃO: QVRS foi comprometida principalmente em seus aspectos funcionais. Por outro lado, a presença de sintomas depressivos contribuiu para a piora da QVRS. A reabilitação deve buscar a melhora da funcionalidade/participação social, o que pode contribuir na redução de sintomas depressivos e a melhora da QVRS.


Asunto(s)
Femenino , Humanos , Masculino , Persona de Mediana Edad , Depresión/psicología , Calidad de Vida , Accidente Cerebrovascular/complicaciones , Actividades Cotidianas , Factores de Edad , Estudios Transversales , Evaluación de la Discapacidad , Índice de Severidad de la Enfermedad , Factores Socioeconómicos , Accidente Cerebrovascular/psicología , Accidente Cerebrovascular/rehabilitación
3.
Rev Soc Bras Med Trop ; 34(3): 239-42, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-11460208

RESUMEN

Parvovirus B19 infects predominantly erythroid cells, leading to transient inhibition of erythropoiesis. Immunocompromised patients may be unable to produce neutralizing antibodies and may develop severe chronic anemia. Epidemiological studies done on Niterói population showed that B19 infection occurs periodically in late spring and summer. We report a study from 55 HIV infected patients attending an infectious diseases outpatient clinic in this city during a 5-month period in which B19 circulation was well documented. All patients were under anti-retroviral therapy. No anti-B19 IgM was found, but a high prevalence of IgG anti-B19 (91%) was observed. In six patients, B19 DNA was found by dot-blot hybridization techniques, but this was not confirmed by PCR. None of these 6 patients manifested anemia and only one had CD4 cell count below 200 x 10(7)/L. We conclude that persistent infection causing anemia is an infrequent finding in our HIV positive patients under drug therapy.


Asunto(s)
Seropositividad para VIH/complicaciones , Infecciones por Parvoviridae/etiología , Parvovirus B19 Humano , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad
4.
Rev. Soc. Bras. Med. Trop ; 34(3): 239-242, maio-jun. 2001.
Artículo en Inglés | LILACS | ID: lil-461981

RESUMEN

Parvovirus B19 infects predominantly erythroid cells, leading to transient inhibition of erythropoiesis. Immunocompromised patients may be unable to produce neutralizing antibodies and may develop severe chronic anemia. Epidemiological studies done on Niterói population showed that B19 infection occurs periodically in late spring and summer. We report a study from 55 HIV infected patients attending an infectious diseases outpatient clinic in this city during a 5-month period in which B19 circulation was well documented. All patients were under anti-retroviral therapy. No anti-B19 IgM was found, but a high prevalence of IgG anti-B19 (91%) was observed. In six patients, B19 DNA was found by dot-blot hybridization techniques, but this was not confirmed by PCR. None of these 6 patients manifested anemia and only one had CD4 cell count below 200 x 10(7)/L. We conclude that persistent infection causing anemia is an infrequent finding in our HIV positive patients under drug therapy.


O parvovírus B19 infecta predominantemente células eritróides, causando inibição transitória da eritropoiese. Pacientes imunocomprometidos podem ser incapazes de produzir anticorpos neutralizantes, evoluindo com grave anemia crônica. Estudos epidemiológicos da população de Niterói mostraram que a infecção ocorre periodicamente no final da primavera e no verão. Descrevem-se 55 pacientes infectados pelo HIV atendidos num ambulatório de doenças infecciosas nesta cidade num período de cinco meses, no qual a circulação do parvovírus B19 foi documentada. Todos os pacientes estavam sob terapia anti-retroviral. Não se encontrou IgM anti-B19, mas notou-se uma prevalência alta de IgG anti-B19 (91%). Em seis pacientes verificou-se a presença de DNA do B19 por hibridização em dot-blot, o que não se confirmou por PCR. Nenhum destes seis pacientes tinha anemia, e apenas um tinha células CD4 abaixo de 200 x 107/L. Conclui-se que infecção persistente causando anemia é um achado infreqüente em nossos pacientes HIV positivos sob terapia medicamentosa.


Asunto(s)
Humanos , Masculino , Femenino , Adulto , Persona de Mediana Edad , Infecciones por Parvoviridae/etiología , Seropositividad para VIH/complicaciones
5.
J Neurosci Res ; 5(3): 241-52, 1980.
Artículo en Inglés | MEDLINE | ID: mdl-7401201

RESUMEN

D-[3-3H]-3-deoxy-3-fluoroglucose was synthesized chemically and shown to be transported into rat brain synaptosomes by a saturable process with a Km 6.2 x 10(-4) M and a Vmax 2.8 nmole x mg protein-1. After an initial, rapid period of transport, further uptake of the fluorosugar is restricted by the rate of its phosphorylation. Both D-glucose and cytochalasin B are competitive inhibitors of 3-deoxy-3-fluoro-D-glucose transport with Ki values of 93 micron and 6.0 x 10(-7) M, respectively. Phloretin, N-ethylmaleimide and p-chloromercuribenzoate also inhibit the fluorosugar uptake, whereas ouabain and changes in K+, Na+, Mg2+ and Ca2+ ions have only a small effect. The recorded 3-deoxy-3-fluoro-D-glucose influx is slightly reduced by potassium cyanide, antimycin A, 2,4-dinitrophenol, and rotenone. The uptake reduction caused by these four reagents is relieved by the addition of exogenous ATP. The possible influence of hexokinse activity on the uptake process is discussed.


Asunto(s)
Corteza Cerebral/metabolismo , Desoxiazúcares/metabolismo , Desoxiglucosa/metabolismo , Sinaptosomas/metabolismo , Adenosina Trifosfato/metabolismo , Animales , Desoxiglucosa/análogos & derivados , Glucosa/metabolismo , Cinética , Masculino , Fosforilación , Ratas
7.
Carbohydr Res ; 73: 125-34, 1979 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-476722

RESUMEN

Treatment of methyl 4-O-mesy-alpha-D-galactopyranoside with benzyl bromide in N,N-dimethylformamide in the presence of silver oxide yielded methyl 2,3,6-tri-O-benzyl-4-O-mesyl-alpha-D-galactopyranoside which with tert-butylammonium fluoride at reflux underwent nucleophilic displacement to give methyl 2,3,6-tri-O-benzyl-4-deoxy-4-fluoro-alpha-D-glucopyranoside. This compound on hydrogenolysis provided crystalline methyl 4-deoxy-4-fluoro-alpha-D-glucopyranoside (9). The structure of 9 was established by its conversion to the 2,3,6-tri-O-acetyl derivative and by n.m.r. and m.s. analysis. Acid hydrolysis of 9 gave 4-deoxy-4-fluoro-D-glucose (1). A modification of an established synthesis of 4-deoxy-D-xylo-hexose (2) from methyl 2,3,6-tri-O-benzoyl-alpha-D-galactopyranoside is described. A systematic comparison was made of the transport parameters (Kx and Vmax) of D-glucose, 2, and 1 in human erythrocytes. The Kx values observed for the above sugars are: 4.0mM, 4.5mM, and 4.6mM, respectively. These results indicate that O-4 in beta-D-glucopyranose is not involved in hydrogen bonding to the carrier protein associated with the transport of D-glucose in the erythrocyte.


Asunto(s)
Desoxiazúcares/análogos & derivados , Desoxiglucosa/análogos & derivados , Eritrocitos/metabolismo , Transporte Biológico , Desoxiglucosa/sangre , Desoxiglucosa/síntesis química , Cromatografía de Gases y Espectrometría de Masas , Humanos , Cinética , Espectroscopía de Resonancia Magnética
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA