ABSTRACT
We report on the growth and microstructure analysis of high Cd content ZnCdO/ZnO multiple quantum wells (MQW) within a nanowire. Heterostructures consisting of ten wells with widths from 0.7 to 10 nm are demonstrated, and show photoluminescence emissions ranging from 3.03 to 1.97 eV. The wells with thicknesses â¦Ì¸2 nm have high radiative efficiencies compared to the thickest ones, consistent with the presence of quantum confinement. However, a nanometric analysis of the Cd profile along the heterostructures shows the presence of Cd diffusion from the ZnCdO well to the ZnO barrier. This phenomenon modifies the band structure and the optical properties of the heterostructure, and is considered in order to correctly identify quantum effects in the ZnCdO/ZnO MQWs.
ABSTRACT
In this work we present a systematic study of ZnO micro and nanostructures grown by spray pyrolysis (SP) and by physical vapour transport (PVT) on glass and c-sapphire substrates at low temperatures. Optimised growth conditions have allowed to obtain homogeneous ZnO nanolayers composed of quasi-spherical nanoparticles in the range 2 to 8 nm by spray pyrolysis, while by PVT the selected growth conditions allow to produce a wide variety of morphologies (tripods, grains, arrows and wires) of nano and microsize dimension. Grazing incidence X-ray diffraction, field emission scanning electron microscopy (FE-SEM), high resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED) and energy dispersive X-ray spectroscopy (EDX) were used as characterization techniques in the investigation of structural, morphological and compositional nature of these nanostructures in relation with the growth method.
ABSTRACT
INTRODUCTION: According to the current literature on the subject, patients with syncope suffer a dysfunction of the autonomic nervous system (ANS). Yet few studies offer a clear explanation of this dysfunction. Moreover, the evaluation of cardiovascular reflexes is a simple, useful method of studying the functional status of the ANS. This work was designed to evaluate the existence of dysautonomia in syncope patients by means of the autonomic cardiovascular stimulation tests; it has been the most comprehensive of those published to date. SUBJECTS AND METHODS: We studied 170 healthy volunteers and 188 patients with syncopes in the previous months, paired by age and sex. Cardiovascular stimulation tests were conducted, in accordance with Ewing and Clark's methodology, together with the cold test. A rating scale was included to evaluate the symptoms related to ANS involvement. RESULTS: Syncope patients display lower reactivity in tests involving cardiovascular stimulation of the ANS, regardless of whether they are taken individually or as a whole (67% in patients and 39% in controls) (p = 0.0001), except in the cold test. They also show an increase in the clinical symptoms of an autonomic origin (2.82 +/- 0.17) with respect to control subjects (0.78 +/- 0.09) (p = 0.0001). CONCLUSIONS: Our syncope patients have a dysautonomia that appears as a sympathetic and parasympathetic hypofunction. These findings confirm the value of autonomic cardiovascular stimulation tests in the study of these patients. Moreover, the search for other symptoms of autonomic involvement can be a great aid in evaluating this pathology.
Subject(s)
Autonomic Nervous System/physiopathology , Cardiovascular System/physiopathology , Syncope/physiopathology , Female , Humans , Male , Middle AgedABSTRACT
Introducción. La bibliografía actual considera que en lospacientes con síncope existe una disfunción del sistema nerviosoautónomo (SNA). Sin embargo, existen pocos estudios que objetivendicha disfunción. Por otra parte, la valoración de los reflejoscardiovasculares constituye un método de estudio sencillo y útil delestado funcional del SNA. Este trabajo se diseñó para valorar laexistencia de disautonomía en pacientes con síncope mediante lostests de estimulación autonómica cardiovascular; ha sido el másnumeroso de los publicados hasta ahora. Sujetos y métodos. Estudiamosa 170 voluntarios sanos y 188 pacientes con síncopes en los meses previos, pareados por edad y sexo. Se realizaron los testsde estimulación cardiovascular, según la metodología de Ewing yClark, y el test del frío. Se incluyó una escala de valoración de lossíntomas relacionados con la afectación del SNA. Resultados. Lospacientes con síncope presentan una menor reactividad en los testsde estimulación cardiovascular del SNA, tomados de forma aisladao en su conjunto (67% en los pacientes y 39% en los controles)(p = 0,0001), si exceptuamos el test del frío. También refieren unaumento de la sintomatología de origen autonómico (2,82 ± 0,17)con respecto a los controles (0,78 ± 0,09) (p = 0,0001). Conclusión.Nuestros pacientes con síncope presentan una disautonomíaque se muestra como una hipofunción simpática y parasimpática.Estos resultados confirman la utilidad de los tests de estimulaciónautonómica cardiovascular en el estudio de dichos pacientes. Porsu parte, la búsqueda de otros síntomas de afectación autonómicapuede ser de gran ayuda para la valoración de esta patología
Introduction. According to the current literature on the subject, patients with syncope suffer a dysfunction of theautonomic nervous system (ANS). Yet few studies offer a clear explanation of this dysfunction. Moreover, the evaluation ofcardiovascular reflexes is a simple, useful method of studying the functional status of the ANS. This work was designed toevaluate the existence of dysautonomia in syncope patients by means of the autonomic cardiovascular stimulation tests; it hasbeen the most comprehensive of those published to date. Subjects and methods. We studied 170 healthy volunteers and 188patients with syncopes in the previous months, paired by age and sex. Cardiovascular stimulation tests were conducted, inaccordance with Ewing and Clarks methodology, together with the cold test. A rating scale was included to evaluate thesymptoms related to ANS involvement. Results. Syncope patients display lower reactivity in tests involving cardiovascularstimulation of the ANS, regardless of whether they are taken individually or as a whole (67% in patients and 39% in controls)(p = 0.0001), except in the cold test. They also show an increase in the clinical symptoms of an autonomic origin (2.82 ± 0.17)with respect to control subjects (0.78 ± 0.09) (p = 0.0001). Conclusions. Our syncope patients have a dysautonomia thatappears as a sympathetic and parasympathetic hypofunction. These findings confirm the value of autonomic cardiovascularstimulation tests in the study of these patients. Moreover, the search for other symptoms of autonomic involvement can be agreat aid in evaluating this pathology
Subject(s)
Male , Female , Adult , Humans , Syncope/diagnosis , Syncope/physiopathology , Autonomic Nervous System Diseases , Disability Evaluation , Cardiovascular Diseases , Case-Control StudiesABSTRACT
The study area is characterized by a maritime Mediterranean climate, abundant presence of Chenopodiaceae in the vegetation, and a high incidence of pollinosis caused by the pollen of this family. A Hirst-type sampler was used to determine pollen concentrations in the air of the city of Huelva during 3 consecutive years (1995-1997). The total annual amount of Chenopodiaceae-Amaranthaceae pollen was between 10.59% and 6.28% of the pollen spectrum of the city, depending on the year. The annual pattern of variation in pollen concentration (5-day means) was very similar in the 3 years, and no statistically significant differences were found between years. This pattern is characterized by concentrations not exceeding 20 grains/m3 between April and the beginning of August, with an obvious seasonal variation in the second half of August and September, when the 5-day mean concentrations exceeded 40 grains/m3 and the daily maxima exceeded 100 grains/m3. This coincided with the flowering of most of the species in the group. The meteorological parameters with a statistically significant effect on daily pollen concentration during the pollen season (August 15 to September 20) included mean temperature and south wind (positive correlations) and relative humidity of the air (negative correlation). The highest intradiurnal concentrations were found between 10:00 a.m. and 5:00 p.m.
Subject(s)
Chenopodiaceae , Magnoliopsida , Pollen , Allergens , Humans , Hypersensitivity, Immediate/immunology , Meteorological Concepts , Seasons , Skin Tests , SpainABSTRACT
The triglyceride composition of avocado oil was determined by high-performance liquid chromatography using a light-scattering detector. Two avocado varieties, Fuerte and Hass, were analysed, and the qualitative composition of each was found to be similar, though quantitative differences were detected. The triglyceride composition was predicted using a system of equations based on the relationship between log k' and the molecular variables equivalent carbon number, chain length and number of double bonds for each of the fatty acids in the glycerides. A total of 24 molecular species of triglycerides were identified. The chromatographic system used successfully separated the critical pairs OOO-LOS, PaPaO-LnPP and PaOO-LOP (O = olein; L = linolein; S = stearin; Pa = palmitolein; Ln = linolenin; P = palmitin). Detector response was found to have a linear relationship with the amount of sample injected over the injection range 10-70 micrograms.
Subject(s)
Fruit/chemistry , Plant Oils/analysis , Triglycerides/analysis , Chromatography, High Pressure Liquid , Freeze Drying , Light , Scattering, RadiationABSTRACT
Prepuberal gynecomastia is extremely rare. We present a case of unilateral and idiopathic gynecomastia in a six years old male. Endocrinology test and anamnesis did not find pathology or drug ingestion. A mastectomy was performed, because the big size and progressive evolution of breast produced physicology problems. We review the literature and remark infrequent aspects of our case, also the complete clinic and pathologic study.
