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1.
Phys Rev Lett ; 111(11): 114801, 2013 Sep 13.
Artículo en Inglés | MEDLINE | ID: mdl-24074093

RESUMEN

Initiating the gain process in a free-electron laser (FEL) from an external highly coherent source of radiation is a promising way to improve the pulse properties such as temporal coherence and synchronization performance in time-resolved pump-probe experiments at FEL facilities, but this so-called "seeding" suffers from the lack of adequate sources at short wavelengths. We report on the first successful seeding at a wavelength as short as 38.2 nm, resulting in GW-level, coherent FEL radiation pulses at this wavelength as well as significant second harmonic emission at 19.1 nm. The external seed pulses are about 1 order of magnitude shorter compared to previous experiments allowing an ultimate time resolution for the investigation of dynamic processes enabling breakthroughs in ultrafast science with FELs. The seeding pulse is the 21st harmonic of an 800-nm, 15-fs (rms) laser pulse generated in an argon medium. Methods for finding the overlap of seed pulses with electron bunches in spatial, longitudinal, and spectral dimensions are discussed and results are presented. The experiment was conducted at FLASH, the FEL user facility at DESY in Hamburg, Germany.

2.
Rev. argent. dermatol ; Rev. argent. dermatol;102(4): 1-10, dic. 2021. graf
Artículo en Español | LILACS-Express | LILACS | ID: biblio-1394700

RESUMEN

Resumen 22. El linfangioma circunscripto (LC) es una afección rara y benigna, caracterizada principalmente por la malformación de los vasos linfáticos de la piel. De etiología congénita o adquirida,esta última debido a causas secundarias como radioterapia, infecciones o procedimientos quirúrgicos. 23. Presentamos el caso de un paciente de 75 años de edad, con antecedente quirúrgico de fimosis a los 29 años, y posterior desarrollo de linfangioma circunscripto de glande diagnosticado 46 años después. El tratamiento definitivo planteado en interconsulta con Urología fue la resección quirúrgica, motivados por la escasa frecuencia de recidivas cuando se usa este método.


Summary 27. Circumscribed lymphangioma (CL) is a rare and benign condition, characterized mainly by malformation of the lymphatic vessels of the skin. It has a congenital or acquired etiology, the latter due to secondary effects such as radiotherapy, infections or surgical procedures. 28. We present the case of a 75-year-old patient, with a surgical history of phimosis at 29 years of age, and subsequent development of circumscribed lymphangioma of the glans penis diagnosed 46 years later. The definitive treatment proposed in consultation with Urology was surgical resection due to the low frequency of recurrences.

3.
Biosystems ; 33(2): 75-87, 1994.
Artículo en Inglés | MEDLINE | ID: mdl-7811960

RESUMEN

We present evidence for a mechanism of eukaryotic cell movement. The pseudopodial dynamics and shape of Dictyostelium discoideum amoebae were investigated using computer-supported video microscopy. An examination of the cell periphery by the novel method of serial circular maps revealed explicit, classical wave patterns, which indicate the existence of intrinsic intracellular oscillations. The patterns are generated by the transit of self-organized, super-positioned, harmonic modes of rotating oscillatory waves (ROWS). These waves are probably associated with the dynamics of intracellular actin polymerisation and depolymerisation. A Karhunen-Loève expansion was conducted on one cell during 10 min of locomotion using points each 10 degrees around the cell's boundary. The results show that only 2-3 modes are necessary to describe the most essential features of cell movement and shape. Based on this analysis, a wave model was developed, which accurately simulates the dynamics of cell movement and shape during this time. The model was tested by reconstructing the cell's dynamical form by means of the Karhunen-Loève transform. No difference was detected between this reconstruction and the actual cell outline. Although cell movement and shape have hitherto been viewed as random, our results demonstrate that ROWS determine the spatio-temporal expression of pseudopodia, and consequently govern cell shape and movement, non-randomly.


Asunto(s)
Movimiento Celular , Tamaño de la Célula , Dictyostelium/citología , Animales , Citoplasma/fisiología , Procesamiento de Imagen Asistido por Computador , Modelos Teóricos , Factores de Tiempo , Grabación en Video
4.
Percept Mot Skills ; 64(2): 391-7, 1987 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-3588184

RESUMEN

This experiment tested the hypothesis that syntactic constituents in American Sign Language (ASL) serve as perceptual units. We adapted the strategy first employed by Fodor and Bever in 1965 in a study of the psychological reality of linguistic speech segments. Four deaf subjects were shown ASL sign sequences constructed to contain a single constituent break. The dependent measure was the subjective location of a light flash occurring during the sign sequence. The prediction that the flashes would be attracted to the constituent boundary was supported for two of the subjects, while the other two showed random placement of the flash location on either side of the constituent boundary. The two subjects not performing in the predicted direction were more proficient in English (written) than the two giving the effect. It was suggested that this relatively greater proficiency may have interfered in some way with the ASL syntax to produce the results obtained.


Asunto(s)
Sordera/psicología , Comunicación Manual , Semántica , Lengua de Signos , Adulto , Sordera/rehabilitación , Humanos , Masculino
5.
Percept Mot Skills ; 58(2): 675-8, 1984 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-6739261

RESUMEN

We argue that the simple wavelength interpretation of the auditory kappa effect proposed by Yoblick and Salvendy in 1970 is inadequate since only the frequency of an incoming soundwave is preserved at the tympanic membrane. Alternative explanations are proposed in terms of psychological variables. The kappa effect with tonal intervals is explained using an imputed velocity model in which frequency differences are equated to phenomenological "distances." The continuous tone effect is explained in terms of previously observed correlations between frequency and the volume or " bigness " of a tone and between size and perceived duration.


Asunto(s)
Percepción Auditiva , Percepción del Tiempo , Estimulación Acústica , Humanos
6.
Percept Mot Skills ; 65(3): 899-906, 1987 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-3438135

RESUMEN

It has been suggested that the hypnotic state results in a greater relative activation or priming of the right cerebral hemisphere than of the left hemisphere. The experiment reported here employed hypnosis to produce such a priming effect in a visual-detection task. Subjects were required to detect the presence or absence of a gap in outline squares presented either to the left visual field or right visual field, with response time as the primary dependent measure. Those subjects who were hypnotized produced a 50-msec. response time difference favoring squares presented to the left visual field whereas control subjects and simulator-control subjects showed no lateral asymmetries. The result is classified as a material-nonspecific priming effect and discussed with regard to the nature of processing resources.


Asunto(s)
Dominancia Cerebral , Percepción de Forma , Hipnosis , Reconocimiento Visual de Modelos , Atención , Humanos , Desempeño Psicomotor , Tiempo de Reacción
9.
Atherosclerosis ; 197(1): 303-10, 2008 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-17588581

RESUMEN

Aggressive inhibition of renin-angiotensin-aldosterone system may provide the best cardiovascular protection. We examined the effect of different doses of angiotensin II receptor blocker, Candesartan, on arterial elasticity, inflammatory and metabolic parameters in hypertensive patients with multiple cardiovascular risk factors. 69 hypertensive patients were randomized into three groups: group 1 included patients treated with high doses of Candesartan (32 mg), group 2 included patients treated with conventional doses of Candesartan (16 mg), group 3 included patients that received antihypertensive treatment other that angiotensin II type-1 receptor blockers (ARBs) or angiotensin-converting enzyme inhibitors (ACEIs). Patients were evaluated for lipid profile, HbA1C, insulin, C-peptide, hs-CRP, aldosterone, renin and Homeostasis model assessment-insulin resistance (HOMA-IR). Arterial elasticity was evaluated using pulse wave contour analysis method (HDI CR 2000, Eagan, Minnesota). In patients treated with high doses of Candesartan: large artery elasticity index (LAEI) increased from 8.6+/-2.8 to 16.6+/-5.1 ml/mm Hg x 100 after 6 months of treatment (p<0.0001). Small artery elasticity index (SAEI) increased from 2.7+/-1.3 to 5.9+/-2.8 ml/mm Hg x 100 (p<0.0001). Systemic vascular resistance (SVR) decreased from 1881.5+/-527.5 to 1520.9+/-271.8 (p<0.0006). In patients treated with conventional doses of Candesartan: LAEI index increased from 11.0+/-3.5 to 14.4+/-3.2 ml/mm Hg x 100 (p<0.0001). SAEI increased during the study from 3.7+/-1.4 to 5.4+/-2.1 ml/mm Hg x 100 (p<0.0001). SVR decreased from 1699.8+/-327.6 to 1400.7+/-241 (p<0.0001). In the control group: neither LAE nor SAE improved during the treatment period. Although similar reduction in blood pressure was observed in all three groups, both LAE and SAE improved only in patients treated by ARBs. Treatment with high doses of Candesartan improves arterial stiffness to a greater extent than conventional doses of Candesartan, despite comparable changes in blood pressure.


Asunto(s)
Bloqueadores del Receptor Tipo 1 de Angiotensina II/administración & dosificación , Bencimidazoles/administración & dosificación , Presión Sanguínea/efectos de los fármacos , Hipertensión/tratamiento farmacológico , Tetrazoles/administración & dosificación , Anciano , Arterias/efectos de los fármacos , Arterias/fisiología , Compuestos de Bifenilo , Adaptabilidad/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Elasticidad/efectos de los fármacos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Flujo Pulsátil/efectos de los fármacos , Resistencia Vascular/efectos de los fármacos
10.
Brain Cogn ; 4(1): 13-26, 1985 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-4027053

RESUMEN

Recent research on the division of processing between the two cerebral hemispheres has often employed two concurrent tasks to investigate the dynamic nature of hemispheric asymmetries. The experiment reported here explored the effects of two concurrent high-level cognitive tasks (memory retention and semantic categorization) on the direction and magnitude of hemispheric differences in the processing of words and pictures. Subjects were required to categorize words and pictures presented to either the left visual field-right hemisphere (LVF-RH) or the right visual field-left hemisphere (RVF-LH). The categorization could be performed while holding either verbal material in memory (digit span), pictorial material in memory (serial nonsense figure recognition), or with no concurrent memory task. The effects produced hemisphere-specific, material-nonspecific interference. The verbal task removed a RVF-LH advantage at word categorization and enhanced a LVF-RH advantage on picture categorization; the pictorial task interfered with picture categorization in the LVF-RH, while enhancing a RVF-LH advantage at word categorization. The results are discussed in terms of multiple resource models of hemisphere function, capacity limitations, and the functional locus of processing required to produce various dynamic hemispheric effects.


Asunto(s)
Atención , Dominancia Cerebral , Percepción de Forma , Memoria , Recuerdo Mental , Reconocimiento Visual de Modelos , Humanos , Retención en Psicología
11.
Radiology ; 124(2): 521, 1977 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-877299

RESUMEN

Illustrated explanations of various diagnostic radiology procedures have been designed to inform children and their parents precisely what will occur during the examinations. These explanations have been well received and may be requested from the author's.


Asunto(s)
Comunicación , Hospitales Pediátricos , Hospitales Especializados , Radiografía , Adolescente , Niño , Preescolar , Femenino , Humanos , Masculino , Servicio de Radiología en Hospital , Estados Unidos
12.
JOGN Nurs ; 13(4): 223-9, 1984.
Artículo en Inglés | MEDLINE | ID: mdl-6565106

RESUMEN

At least 25% of all menstruating women suffer from the premenstrual syndrome (PMS). The complex nature and incidence of PMS are explored. A PMS Clinic Nursing Protocol is provided to facilitate recognition, evaluation, and management of the syndrome. Both nonpharmacologic and drug therapies are included under interventions for the individual woman experiencing premenstrual dysphoria. Community management is also described.


Asunto(s)
Síndrome Premenstrual/fisiopatología , Adulto , Dieta , Femenino , Hormonas/fisiología , Humanos , Anamnesis , Examen Físico , Síndrome Premenstrual/diagnóstico , Síndrome Premenstrual/terapia , Progesterona/uso terapéutico , Piridoxina/uso terapéutico , Autocuidado
13.
Planta ; 135(2): 149-54, 1977 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-24420017

RESUMEN

The intial phases of auxin-induced growth in coleoptile segments of Avena sativa L. were investigated using a high resolution growth recording technique, based on an angular position sensing transducer. The first response to the hormone is a slight, transient reduction of the growth rate lasting about 5 min. After this phase growth rate increases to a maximum. The duration of the increase and the maximum clearly depend on the concentration of the hormone. With increasing auxin concentration the duration of the growth rate increase is reduced from about 80 min in 10(-9) M indoleacetic acid (IAA) to about 14 min in 10(-4) M IAA. After the maximum the growth rate declines. Looking at the maximum of the growth rate, we obtained a dose-response curve with a sharp increase between 10(-9) M and 10(-6) M IAA and a slight decline between 10(-6) M and 10(-4) M IAA. This result is confirmed by growth rates measured one and two hours after the application of the hormone.

14.
J Intern Med ; 247(2): 260-8, 2000 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-10692090

RESUMEN

OBJECTIVES: Sunlight exposure of the skin is known to be the most important source of vitamin D. The aims of this study were: (i) to estimate vitamin D status amongst sunlight-deprived individuals (veiled Arab women, veiled ethnic Danish Moslem women and Danish controls); and (ii) through food intake analysis to estimate the oral intake of vitamin D necessary to keep a normal vitamin D status in sunlight-deprived individuals. DESIGN: Cross-sectional study amongst randomly selected Moslem women of Arab origin living in Denmark. Age-matched Danish women were included as controls. To control for racial differences, a group of veiled ethnic Danish Moslem women (all Caucasians) was included. SETTING: Primary Health Care Centre, City Vest and Department of Endocrinology and Metabolism C, University Hospital of Aarhus, Aarhus Amtssygehus, Aarhus, Denmark. SUBJECTS: Sixty-nine Arab women (60 veiled, nine non-veiled) and 44 age-matched Danish controls were randomly selected amongst patients contacting the primary health care centre for reasons other than vitamin D deficiency. Ten ethnic Danish Moslem women were included through a direct contact with their community. MAIN OUTCOME MEASURES: Serum levels of 25-hydroxyvitamin D were used as estimates of vitamin D status. Intact parathyroid hormone (PTH) was used to control for secondary hyperparathyroidism. Alkaline phosphatase and bone-specific alkaline phosphatase were used as markers for osteomalacic bone involvement. Oral intake of vitamin D and calcium were estimated through a historical food intake interview performed by a trained clinical dietician. RESULTS: Veiled Arab women displayed extremely low values of 25-hydroxyvitamin D: 7.1 +/- 1.1 nmol L-1, compared with 17.5 +/- 2. 3 (P < 0.002) in ethnic Danish Moslems and 47.1 +/- 4.6 (P < 10-17) in Danish controls. PTH was increased amongst veiled Arab women: 15. 6 +/- 1.8 pmol L-1, compared with 5.7 +/- 1.4 in ethnic Danish Moslems and 2.7 +/- 0.3 (P < 10-6) in Danish controls. The vitamin D intake (including food supplementation) was very low amongst Arab women: 1.04 microg day-1, compared with 13.53 amongst ethnic Danish Moslems and 7.49 amongst Danish controls (P < 0.0005). CONCLUSIONS: Severe vitamin D deficiency is prevalent amongst sunlight-deprived individuals living in Denmark. In veiled Arab women, vitamin D deficiency is the result of a combination of limitations in sunlight exposure and a low oral intake of vitamin D. The oral intake of vitamin D amongst veiled ethnic Danish Moslems was, however, very high, at 13.53 microgram (approximately 600 IU), but they were still vitamin D-deficient. Our results suggest that the daily oral intake of vitamin D in sunlight-deprived individuals should exceed 600 IU; most probably it should be 1000 IU day-1 to secure a normal level of 25-hydroxyvitamin D. This finding is in contrast with the commonly used RDA (recommended daily allowance) for adults in Europe: 200 IU day-1.


Asunto(s)
Árabes , Vestuario/efectos adversos , Luz Solar , Deficiencia de Vitamina D/etiología , Vitamina D/análogos & derivados , Vitamina D/administración & dosificación , Adulto , Fosfatasa Alcalina/sangre , Calcio/sangre , Calcio/orina , Estudios de Casos y Controles , Creatinina/sangre , Estudios Transversales , Dinamarca/etnología , Conducta Alimentaria , Femenino , Humanos , Hidroxiprolina/orina , Hiperparatiroidismo Secundario/sangre , Hiperparatiroidismo Secundario/diagnóstico , Magnesio/sangre , Política Nutricional , Hormona Paratiroidea/sangre , Fosfatos/sangre , Rayos Ultravioleta , Vitamina D/sangre , Deficiencia de Vitamina D/sangre
15.
Calcif Tissue Int ; 66(6): 419-24, 2000 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-10821877

RESUMEN

The aims of this study were to investigate myopathy in relation to vitamin D status, and to study the muscular effects of vitamin D treatment on vitamin D-deficient individuals. Further, hypovitaminosis D myopathy was investigated in relation to alkaline phosphatase (ALP), the most commonly used marker for hypovitaminosis D osteopathy. Eight patients with osteomalacia had an isokinetic dynamometer test of all major muscle groups before and after 3 months of vitamin D treatment. The most pronounced improvements in muscle power were seen in the weight-bearing antigravity muscles of the lower limbs. A cross-sectional study was performed among 55 vitamin D-deficient veiled Arab women living in Denmark and 22 Danish controls. An isometric dynamometer model was used for determination of quadriceps muscle power. Both maximal voluntary contraction (MVC) and electrically stimulated values (single twitch, maximal production rate (MPR), and maximal relaxation rate (MRR)) were determined. The women underwent high-dose vitamin D treatment and were retested after 3 and 6 months. Prior to vitamin D treatment all parameters of muscle function in the group of vitamin D-deficient Arab women were significantly reduced compared with Danish controls. MVC: 259.4 +/- 11.0 N (Newton) versus 392.6 +/- 11. 4 N (P < 10(-6)), single twitch: 47.0 +/- 1.8 N versus 74.6 +/- 2.2 N (P < 10(-5)), MPR 8.9 +/- 0.3 N/10 ms versus 14.3 +/- 0.4 N/10 ms (P < 10(-6)), MRR 4.5 +/- 0.2 N/10 ms versus 6.2 +/- 0.2 N/10 ms (P < 10(-6)). Muscle function was affected to a similar degree in women with and without bone involvement (as indicated by elevated ALP). After 3 months of vitamin D treatment all muscle-related parameters improved significantly. After 6 months only MVC was reduced compared with Danish controls (320.7 +/- 14.3 N (P < 0.02)), whereas all other measurements were normalized. Hypovitaminosis D myopathy is a prominent symptom of vitamin D deficiency, and severely impaired muscle function may be present even before biochemical signs of bone disease develop. Full normalization of hypovitaminosis D myopathy demands high-dose vitamin D treatment for 6 months or more. Our findings indicate that serum levels of ALP cannot be used in the screening for hypovitaminosis D myopathy. Assessment of s-25OHD is the only reliable test.


Asunto(s)
Enfermedades Musculares/etiología , Osteomalacia/complicaciones , Deficiencia de Vitamina D/complicaciones , Fosfatasa Alcalina/sangre , Árabes , Estudios Transversales , Dinamarca , Femenino , Humanos , Masculino , Persona de Mediana Edad , Contracción Muscular/efectos de los fármacos , Músculo Esquelético/efectos de los fármacos , Músculo Esquelético/fisiología , Enfermedades Musculares/sangre , Osteomalacia/sangre , Osteomalacia/tratamiento farmacológico , Factores de Tiempo , Vitamina D/sangre , Vitamina D/uso terapéutico , Deficiencia de Vitamina D/sangre
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