Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 33
Filtrar
1.
Phys Rev Lett ; 89(1): 011301, 2002 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-12097025

RESUMEN

Observations of neutral-current nu interactions on deuterium in the Sudbury Neutrino Observatory are reported. Using the neutral current (NC), elastic scattering, and charged current reactions and assuming the standard 8B shape, the nu(e) component of the 8B solar flux is phis(e) = 1.76(+0.05)(-0.05)(stat)(+0.09)(-0.09)(syst) x 10(6) cm(-2) s(-1) for a kinetic energy threshold of 5 MeV. The non-nu(e) component is phi(mu)(tau) = 3.41(+0.45)(-0.45)(stat)(+0.48)(-0.45)(syst) x 10(6) cm(-2) s(-1), 5.3sigma greater than zero, providing strong evidence for solar nu(e) flavor transformation. The total flux measured with the NC reaction is phi(NC) = 5.09(+0.44)(-0.43)(stat)(+0.46)(-0.43)(syst) x 10(6) cm(-2) s(-1), consistent with solar models.

2.
Phys Rev Lett ; 89(1): 011302, 2002 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-12097026

RESUMEN

The Sudbury Neutrino Observatory (SNO) has measured day and night solar neutrino energy spectra and rates. For charged current events, assuming an undistorted 8B spectrum, the night minus day rate is 14.0%+/-6.3%(+1.5%)(-1.4%) of the average rate. If the total flux of active neutrinos is additionally constrained to have no asymmetry, the nu(e) asymmetry is found to be 7.0%+/-4.9%(+1.3%)(-1.2%). A global solar neutrino analysis in terms of matter-enhanced oscillations of two active flavors strongly favors the large mixing angle solution.

3.
Phys Rev Lett ; 87(7): 071301, 2001 Aug 13.
Artículo en Inglés | MEDLINE | ID: mdl-11497878

RESUMEN

Solar neutrinos from (8)B decay have been detected at the Sudbury Neutrino Observatory via the charged current (CC) reaction on deuterium and the elastic scattering (ES) of electrons. The flux of nu(e)'s is measured by the CC reaction rate to be straight phi(CC)(nu(e)) = 1.75 +/- 0.07(stat)(+0.12)(-0.11)(syst) +/- 0.05(theor) x 10(6) cm(-2) s(-1). Comparison of straight phi(CC)(nu(e)) to the Super-Kamiokande Collaboration's precision value of the flux inferred from the ES reaction yields a 3.3 sigma difference, assuming the systematic uncertainties are normally distributed, providing evidence of an active non- nu(e) component in the solar flux. The total flux of active 8B neutrinos is determined to be 5.44+/-0.99 x 10(6) cm(-2) s(-1).

4.
Homo ; 52(1): 72-6, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-11515398

RESUMEN

Human bone samples of 123 Alemans of the 5th to 7th c AD were investigated for nicotine. In 23 individuals nicotine was found at levels between 31 and 150 ng/g, and in 49 others nicotine was found in traces. The results indicate that in Germany plants of the genus Nicotiana should have been present, known and used, well before Columbus. The purposes behind this use might have been domestic/medical or ritual, or possibly even as a luxury as occurs today.


Asunto(s)
Huesos/química , Nicotina/historia , Femenino , Alemania , Historia Medieval , Humanos , Masculino , Nicotina/análisis , Nicotina/farmacocinética , Nicotiana
6.
Exp Clin Endocrinol Diabetes ; 105(6): 336-40, 1997.
Artículo en Inglés | MEDLINE | ID: mdl-9439929

RESUMEN

Immunoreactive parathyroid hormone-related protein (PTH-rP) was measured in simultaneously obtained cerebrospinal fluid (CSF) and plasma from 51 patients suspected of suffering from a prolapsed intervertebral disc. Endocrine or psychiatric diseases were excluded. In addition, immunoreactive parathyroid hormone (PTH) in the CSF samples was measured. Both, PTH-rP and PTH were assayed by immunoradiometric assay. The results indicate the presence of both, PTH-rP and PTH in CSF. The following concentrations (mean values +/- SD) were found: PTH-rP (pmol/l) in CSF without pleocytosis (n = 17) 0.432 +/- 0.157, with pleocytosis (n = 34) 0.654 +/- 0.675; in plasma (pmol/l) 54.1 +/- 14.632; PTH (nmol/l) in CSF without pleocytosis (n = 17) 0.454 +/- 0.099, with pleocytosis (n = 34) 0.437 +/- 0.140, and in plasma 4.272 +/- 0.794. The concentrations of both, PTH-rP and PTH, in CSF with and without pleocytosis were not significantly different. No correlation was found between PTH-rP and PTH values. The present study demonstrated PTH-rP as a normal constituent in human CSF.


Asunto(s)
Líquido Cefalorraquídeo/química , Proteínas/análisis , Adolescente , Adulto , Anciano , Humanos , Disco Intervertebral , Persona de Mediana Edad , Hormona Paratiroidea/líquido cefalorraquídeo , Proteína Relacionada con la Hormona Paratiroidea , Prolapso , Valores de Referencia , Enfermedades de la Columna Vertebral/líquido cefalorraquídeo
7.
Anthropol Anz ; 54(4): 341-53, 1996 Dec.
Artículo en Alemán | MEDLINE | ID: mdl-9092385

RESUMEN

Human remains from excavation sites in southern China, dated from 100 to 10,000 years, were investigated for nicotine. The nicotine concentrations were measured by radioimmunoassay. Consequently, the values measured represent the sum of nicotine and its metabolites. Positive results were observed in 25.9% (mean values of all samples). The concentrations ranged from 11.8 to 474.2 ng/g sample. From the excavation sites with the highest number of individuals, Chongtong (18 individuals) were 38.9%, and from the site Leigund (21 individuals) were 28.6% from the samples nicotine positive. The highest level with 474.2 ng/g nicotine was found in a sample dated 100 years. It is possible, that this individual was smoker. In addition the samples were investigated also by gas chromatography/mass spectrometry. The GC/MS indicated the presence of nicotine and its primary metabolite, cotinine. The presence of cotinine points out the assumption that nicotine was used antemortem. The detection of unchanged nicotine indicates that nicotine remained present in bones up centuries.


Asunto(s)
Huesos/química , Cotinina/historia , Nicotina/historia , China , Cotinina/análisis , Cromatografía de Gases y Espectrometría de Masas , Historia Antigua , Humanos , Nicotina/análisis , Paleopatología , Radioinmunoensayo
8.
Eur J Clin Pharmacol ; 51(3-4): 215-9, 1996.
Artículo en Inglés | MEDLINE | ID: mdl-9010687

RESUMEN

OBJECTIVE: Participants in a phase I study were interviewed in order to establish the incidence and variability of subjective symptoms and changes in quality of life during phase I trials. METHODS: The healthy subjects were randomized to receive a single dose of either 0.5 mg digoxin or an equivalent amount of each of four digitaloid mixtures every 14 days. The trial involved five 24-h monitoring periods. The duration of the study was 57 days. Wellbeing, subjective symptoms and quality of life were measured before, during and after the trial using the Freiburg Symptoms List (FSL), Wellbeing Scales (WBS), and Life Satisfaction Questionnaire (LSQ). RESULTS: Eight healthy subjects (25 years) were enrolled in the study. Their subjective symptoms were below the reference values for healthy subjects for each test but above the theoretical minimum and maximum values for total wellbeing, indicating that healthy subjects-not just patients-display subjective symptoms and impairment of wellbeing to a greater or lesser extent prior to a clinical trial. In terms of the total study population, comparison of the questionnaire scores before, during and after the study disclosed no significant changes in wellbeing or quality of life. However, some participants displayed marked intraindividual fluctuation. CONCLUSIONS: A careful exploration of the baseline symptoms is necessary even in healthy subjects to avoid observation bias. The symptom course differs greatly from individual to individual; therefore in a phase I study only group scores of wellbeing should be used to assess the possible effects of trial-related factors. A setting like the one used in our study does not impair the quality of life of healthy subjects and as such can be regarded as a fairly neutral means of measuring wellbeing.


Asunto(s)
Estado de Salud , Calidad de Vida , Adolescente , Adulto , Digoxina/farmacología , Humanos , Masculino
9.
Hautarzt ; 43(2): 73-6, 1992 Feb.
Artículo en Alemán | MEDLINE | ID: mdl-1548131

RESUMEN

Specimens of apocrine and eccrine sweat collected without and after pilocarpine stimulation from smokers and non-smokers exposed to tobacco smoke were investigated for the presence of nicotine. The concentrations were determined by radioimmunoassay, so that the values obtained represent the concentrations of nicotine plus its metabolites, e.g. cotinine. Measurable nicotine concentrations were found in all samples. The levels measured in apocrine sweat were higher than those in eccrine sweat. The presence of unchanged nicotine in sweat was revealed by GC/MS.


Asunto(s)
Nicotina/farmacocinética , Fumar/metabolismo , Sudor/química , Contaminación por Humo de Tabaco , Adolescente , Adulto , Glándulas Apocrinas/metabolismo , Glándulas Ecrinas/metabolismo , Femenino , Cromatografía de Gases y Espectrometría de Masas , Humanos , Masculino , Radioinmunoensayo , Análisis de Regresión
10.
Fortschr Med ; 110(4): 57-8, 61-2, 1992 Feb 10.
Artículo en Alemán | MEDLINE | ID: mdl-1568692

RESUMEN

OBJECTIVE: Testing of the blood pressure-lowering effect of a slow-release (24 hours) nifedipine preparation. STUDY DESIGN: Single blind, randomized placebo controlled, single cross-over test; duration eight days. PATIENTS: 18 inpatients with essential hypertension and a blood pressure of more than 160/95 mmHg. MEDICATION: A single 60 mg slow-release nifedipine tablet (Aprical long 60 mg) administered daily at 1800 hours. MEASURING PARAMETERS: Pulse and blood pressure measured after 3, 12, 15, 18, 20, 22 and 24 hours post-administration. RESULTS: Even 18 to 24 hours after administration, the systolic blood pressure was reduced on average by 20 mmHg, the diastolic pressure by 14 mmHg. In the case of the test substance, the percentage of blood pressures in the target range (less than 160/95 mmHg) was 40 percentage points (systolic) and 49 percentage points (diastolic) higher than in the case of placebo. In 15 patients, both systolic and diastolic blood pressure was maintained within the defined target range for 24 hours. Reflex tachycardia was not observed, while other side effects such as headache, flushing, hot flashes, and leg edema occurred only rarely. There was evidence that an evening administration of the drug had a favorable effect on the morning blood pressure increase.


Asunto(s)
Presión Sanguínea/efectos de los fármacos , Hipertensión/tratamiento farmacológico , Nifedipino/administración & dosificación , Adulto , Presión Sanguínea/fisiología , Ritmo Circadiano/efectos de los fármacos , Ritmo Circadiano/fisiología , Preparaciones de Acción Retardada , Femenino , Humanos , Hipertensión/sangre , Masculino , Persona de Mediana Edad , Nifedipino/farmacocinética , Método Simple Ciego
11.
Z Rechtsmed ; 103(5): 323-7, 1990.
Artículo en Alemán | MEDLINE | ID: mdl-2356661

RESUMEN

The presence of methadone was investigated in 24-h perspiration samples obtained from patients receiving daily maintenance doses of the drug. The samples were collected from the axillary region. The concentrations measured by radioimmunoassay ranged from 8.3 ng/cm2 per 24 h up to 25.3 ng/cm2 per 24 h. The concentrations determined by RIA are the sum of methadone and its metabolites. The presence of the drug in the perspiration samples were also revealed by GC/MS.


Asunto(s)
Metadona/farmacocinética , Sudor/metabolismo , Adulto , Femenino , Cromatografía de Gases y Espectrometría de Masas , Humanos , Masculino , Metadona/uso terapéutico , Radioinmunoensayo
12.
Beitr Orthop Traumatol ; 36(3): 81-91, 1989 Mar.
Artículo en Alemán | MEDLINE | ID: mdl-2499303

RESUMEN

The application of a low dose of prednisolone (0.4 mg per kg body weigh and day) in young hamsters leads to a loss of bone mass. This effect is inhibited by the administration of the diphosphonate EHDP (6.2 mg per kg body weight and day). The total volume of the limb bones is increased. The application of a high dose of prednisolone (40 mg per kg body weight and day) induces a severe osteopathy. These pathological bone changes couldn't be prevented by EHDP, but there was a significant shift of the investigated parameters into the direction of normalization.


Asunto(s)
Ácido Etidrónico/administración & dosificación , Osteoporosis/inducido químicamente , Prednisolona/toxicidad , Animales , Huesos/efectos de los fármacos , Cricetinae , Masculino , Mesocricetus , Osteoporosis/prevención & control
13.
Radiol Diagn (Berl) ; 30(4): 515-7, 1989.
Artículo en Alemán | MEDLINE | ID: mdl-2798839

RESUMEN

Without the x-ray assistant, regularly involved in everyday practice, technical quality assurance can hardly be accomplished. Therefore a model for the organization of quality assurance was developed and tested in practice. It implies accountable technical checks by the technician, that are controlled by a quality supervisor, and are subsequently evaluated by the radiation physics department. This positively influences quality consciousness of the radiographers and therefore the quality itself.


Asunto(s)
Garantía de la Calidad de Atención de Salud/normas , Radiografía/normas , Tecnología Radiológica , Alemania Oriental , Humanos , Recursos Humanos
14.
Radiat Res ; 111(1): 1-13, 1987 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-3602347

RESUMEN

Measurements in nearly monoenergetic beams of 144, 24.5, and 2 keV neutrons and of thermal neutrons have been performed with low-pressure proportional counters. The suitability of a tissue-equivalent proportional counter (TEPC) for dosimetry of low-energy neutrons has been investigated. In contrast to higher neutron energies, the modification of the primary radiation field by the detector wall and the contribution of secondaries produced in the gas are significant. These effects have been investigated by additional measurements with a carbon-walled proportional counter. The various physical processes of neutron interaction with wall and gas of the TEPC have been analyzed, and absorbed dose, kerma, and kerma contributions from the various processes are presented. In addition, dose contributions from contaminating neutrons and photons have been obtained for the calibration fields used. The results have been related to neutron fluence. The comparison with tabulated kerma factors shows excellent agreement, indicating the suitability of the TEPC method for dosimetry of low-energy neutrons.


Asunto(s)
Neutrones/uso terapéutico , Protección Radiológica/instrumentación , Transferencia de Energía , Neutrones Rápidos/uso terapéutico , Matemática , Control de Calidad , Radioquímica , Dosificación Radioterapéutica
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA