44 research outputs found
Influencia de la hipotiroxinemia materna durante la gestación sobre el desarrollo psicomotor
The maternal thyroid function during early pregnancy
plays a fundamental role in foetal brain development as
synthesis of thyroid hormone does not begin until the 20th
week of gestation.
Material and methods
Throughout the year 2002, 147 women in their 37th week
of pregnancy were enrolled for the study. To evaluate their
thyroid function, the serum concentrations of free T4 and
of TSH were determined. After birth, the psychomotor development
of their children was evaluated with the Mc-
Carthy scales.
Results
The median value of free T4 was 9.37 pmol/l, being the
data obtained from more than half of the sampled women
below the hypothyroxinaemia threshold. Children born
from mothers with T4 levels below percentile 10 showed a
significantly lower score on the general cognitive index
than those whose mothers had normal free T4 serum concentrations.
A positive correlation was found between the
values of maternal free T4 and the general cognitive index
(r 0.43; p < 0.01).
Conclusions
The concentrations of maternal free T4 are important, not
only during the first months of pregnancy, but all along the
process to ensure adequate development of the foetal brain
Insuficiencia respiratoria neonatal asociada a mutación en el gen de la proteína C del surfactante
La insuficiencia respiratoria en el recién nacido a término
durante las primeras semanas de vida extrauterina
es una situación poco frecuente. Entre sus causas se incluyen
las enfermedades difusas del intersticio pulmonar, un
grupo heterogéneo de enfermedades, la mayoría idiopáticas,
caracterizadas por infiltrados difusos, alteraciones
funcionales de tipo restrictivo y afectación del intercambio
gaseoso. Una forma de enfermedad pulmonar intersticial
que puede afectar a lactantes, niños o adultos jóvenes
es la que se asocia al déficit congénito de proteínas B o C
del surfactante pulmonar. En estos casos los procesos inflamatorios
que evolucionan hacia la fibrosis pulmonar están
precedidos por la acumulación de material proteináceo
en el alvéolo.
Se indagó la presencia de mutaciones en los genes de
las proteínas B y C del surfactante en una familia española
en la cual dos lactantes presentaron insuficiencia
respiratoria progresiva desde el nacimiento, con alteraciones
radiológicas y anatomopatológicas compatibles
con enfermedad del intersticio pulmonar, y el padre
refería historia de problemas respiratorios desde la infancia.
Se encontró que los dos hermanos de esta familia afectados
por la enfermedad presentaban una expresión anómala
del precursor de la proteína C del surfactante y concentraciones
muy bajas de proteína madura. Se describe
además una mutación nueva en el gen que codifica la proteína
C del surfactante y que cosegrega con la enfermedad
en esta familia
Linfangioma de pared torácica. A propósito de un caso
Lymphangioma is a benign, congenital type of tumor, derived from lymphatic vessels, and located generally in head and neck. Ultrasonography is the procedure of choice for establishing the diagnosis. The main treatment modality is surgical excision, if it is not mutilating. Intralesional injection OK-432 represents an alternative, safe and effective treatment for lymphangiomas. We present a case of lymphangioma on the thoracic wall, solved after the punction.El linfangioma es una malformación congénita derivada de los vasos linfáticos y localizada generalmente en la cabeza o en el cuello. La ecografía es útil para orientar el diagnóstico. El tratamiento de elección es la cirugía, siempre que no sea mutilante. Existen otras alternativas terapéuticas como la inyección intralesional de agentes esclerosantes como el OK-432 que es seguro y muchas veces eficaz. Presentamos el caso de un linfangioma de pared torácica en un niño cuya resolución aconteció después de la punción-aspiración realizada al diagnóstico
Use of recombinant human granulocyte-macrophage colony stimulating factor in an infant with reticular dysgenesis
We present the case of a 2-month-old infant with reticular dysgenesis who was
treated with recombinant granulocyte-macrophage colony stimulating factor with
the aim of stimulating granulopoiesis while awaiting bone marrow transplant
High quality single crystal Ge nano-membranes for opto-electronic integrated circuitry
Under the terms of the Creative Commons Attribution (CC BY) license to their work.-- et al.A thin, flat, and single crystal germanium membrane would be an ideal platform on which to mount sensors or integrate photonic and electronic devices, using standard silicon processing technology. We present a fabrication technique compatible with integrated-circuit wafer scale processing to produce membranes of thickness between 60 nm and 800 nm, with large areas of up to 3.5 mm2. We show how the optical properties change with thickness, including appearance of Fabry-Pérot type interference in thin membranes. The membranes have low Q-factors, which allow the platforms to counteract distortion during agitation and movement. Finally, we report on the physical characteristics showing sub-nm roughness and a homogenous strain profile throughout the freestanding layer, making the single crystal Ge membrane an excellent platform for further epitaxial growth or deposition of materials.This work was carried out under the RCUK Basic Technology Programme supported by research Grant Nos. EP/F040784/1, EP/J001074/1, and EP/L007010/1. It also received funding from the European Community's Seventh Framework Programme (FP7/2007-2013) under Grant Agreement NANOFUNCTION n°257375 alongside funding from TAPHOR (MAT2012–31392) and FP7 Project MERGING (Grant No. 309150). Vibrational property measurements were funded by the ERC under Grant No. 202735, NonContactUltrasonic.Peer Reviewe
Severe cardiac and abdominal manifestations without lung involvement in a child With COVID-19
Coronavirus disease 2019 (COVID-19) has become a worldwide pandemic, affecting humans of all ages. Clinical features of the pediatric population have been published, but there is not yet enough information to make a definitive description. Fever is typical, as it is respiratory symptom. Rarely are the infection and complications severe, and, when they are, it is almost always in a patient with another underlying disease. However, some otherwise healthy children with COVID-19 do suffer critical organ injury, such as acute myocarditis, heart failure and gastrointestinal inflammation. The mechanism of these organ damages remains unclear. An otherwise normally healthy 13-year-old male was admitted to the pediatric intensive care unit with acute abdomen pain, possible myocarditis and a suspected diagnosis of COVID-19. Noteworthy basal findings were ventricular extrasystoles in the electrocardiogram (EKG) and moderate left ventricular systolic dysfunction. Chest X-ray was normal. Blood tests revealed altered levels of inflammation factors (C-reactive protein (CRP), D-dimer, fibrinogen, interleukin 6 (IL-6)), lymphopenia and elevated cardiac enzymes. The first test for polymerase chain reaction (PCR) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was negative. The patient’s condition worsened, and he entered cardiogenic shock (hypotension, tachycardia and oliguria). He was vomiting continuously, which made pain control difficult; imaging of his abdomen was undertaken. There was no response to fluid resuscitation, and so milrinone and epinephrine were administered. Empiric treatment began with azithromycin, foscarnet, carnitine and immunoglobulins. Hydroxychloroquine was given before the results of repeated SARSCoV-2 and serology tests were available. Tocilizumab was administered once COVID-19 had been confirmed and massive inflammation had been observed. Progressively the clinical situation and the levels
of the parameters studied improved. The patient was discharged 8 days after admission. Most children with SARS-CoV-2 infection are asymptomatic or present only mild symptoms. However, physicians should be aware of atypical and severe manifestations that may occur in the hyperinflammatory phase of the illness
Thermal transport in epitaxial Si1-xGex alloy nanowires with varying composition and morphology
We report on structural, compositional, and thermal characterization of self-assembled in-plane epitaxial Si1-xGex alloy nanowires grown by molecular beam epitaxy on Si (001) substrates. The thermal properties were studied by means of scanning thermal microscopy, while the microstructural characteristics, the spatial distribution of the elemental composition of the alloy nanowires and the sample surface were investigated by transmission electron microscopy and energy dispersive x-ray microanalysis. We provide new insights regarding the morphology of the in-plane nanostructures, their size-dependent gradient chemical composition, and the formation of a 5 nm thick wetting layer on the Si substrate surface. In addition, we directly probe heat transfer between a heated scanning probe sensor and Si1-xGex alloy nanowires of different morphological characteristics and we quantify their thermal resistance variations. We correlate the variations of the thermal signal to the dependence of the heat spreading with the cross-sectional geometry of the nanowires using finite element method simulations. With this method we determine the thermal conductivity of the nanowires with values in the range of 2-3 Wm-1K-1. These results provide valuable information in growth processes and show the great capability of the scanning thermal microscopy technique in ambient environment for nanoscale thermal studies, otherwise not possible using conventional tech-niques
Thermal transport in epitaxial Si1-xGe x alloy nanowires with varying composition and morphology
We report on structural, compositional, and thermal characterization of self-assembled in-plane epitaxial SiGe alloy nanowires grown by molecular beam epitaxy on Si (001) substrates. The thermal properties were studied by means of scanning thermal microscopy (SThM), while the microstructural characteristics, the spatial distribution of the elemental composition of the alloy nanowires and the sample surface were investigated by transmission electron microscopy and energy dispersive x-ray microanalysis. We provide new insights regarding the morphology of the in-plane nanostructures, their size-dependent gradient chemical composition, and the formation of a 5 nm thick wetting layer on the Si substrate surface. In addition, we directly probe heat transfer between a heated scanning probe sensor and SiGe alloy nanowires of different morphological characteristics and we quantify their thermal resistance variations. We correlate the variations of the thermal signal to the dependence of the heat spreading with the cross-sectional geometry of the nanowires using finite element method simulations. With this method we determine the thermal conductivity of the nanowires with values in the range of 2-3 W m K. These results provide valuable information in growth processes and show the great capability of the SThM technique in ambient environment for nanoscale thermal studies, otherwise not possible using conventional techniques
Phonons in Slow Motion: Dispersion Relations in Ultra-Thin Si Membranes
We report the changes in dispersion relations of hypersonic acoustic phonons
in free-standing silicon membranes as thin as \sim 8 nm. We observe a reduction
of the phase and group velocities of the fundamental flexural mode by more than
one order of magnitude compared to bulk values. The modification of the
dispersion relation in nanostructures has important consequences for noise
control in nano and micro-electromechanical systems (MEMS/NEMS) as well as
opto-mechanical devices.Comment: 5 page