992 resultados para Soft Single Switched (SSS)
Resumo:
Camurati-Engelmann disease is characterized by hyperostosis of the long bones and the skull, muscle atrophy, severe limb pain, and progressive joint contractures in some patients. It is caused by heterozygous mutations in the transforming growth factor β1 (TGFβ1) believed to result in improper folding of the latency-associated peptide domain of TGFβ1 and thus in increased or deregulated bioactivity. Losartan, an angiotensin II type 1 receptor antagonist, has been found to downregulate the expression of TGFβ type 1 and 2 receptors. Clinical trials with losartan have shown a benefit in Marfan syndrome, while trials are underway for Duchenne muscular dystrophy and other myopathies associated with TGFβ1 signaling. We hypothesized that due to its anti-TGFβ1 activity, losartan might be beneficial in Camurati-Engelmann disease. This report concerns a boy who presented at age 13 years with severe limb pain and difficulty in walking. Clinical and radiographic evaluation results were compatible with Camurati-Engelmann disease and the diagnosis was confirmed by mutation analysis (c.652C > T [p.Arg218Cys]). The boy underwent an experimental treatment with losartan at a dosage of 50 mg/day, orally. During the treatment period of 18 months, the intensity and frequency of limb pain decreased significantly (as shown by a pain diary), and muscle strength improved, allowing the boy to resume walking and climbing stairs. No obvious side effects were observed. We cautiously conclude that TGFβ1 inhibition with losartan deserves further evaluation in the clinical management of Camurati-Engelmann disease.
Resumo:
In this work a new admittance spectroscopy technique is proposed to determine the conduction band offset in single quantum well structures (SQW). The proposed technique is based on the study of the capacitance derivative versus the frequency logarithm. This method is found to be less sensitive to parasitic effects, such as leakage current and series resistance, than the classical conductance analysis. Using this technique, we have determined the conduction band offset in In0.52Al0.48As/InxGa1¿xAs/In0.52Al0.48As SQW structures. Two different well compositions, x=0.53, which corresponds to the lattice¿matched case and x=0.60, which corresponds to a strained case, and two well widths (5 and 25 nm) have been considered. The average results are ¿Ec=0.49±0.04 eV for x=0.53 and ¿Ec =0.51±0.04 eV for x=0.6, which are in good agreement with previous reported data.
Resumo:
A bidimensional array based on single-photon avalanche diodes for triggered imaging systems is presented. The diodes are operated in the gated mode of acquisition to reduce the probability to detect noise counts interfering with photon arrival events. In addition, low reverse bias overvoltages are used to lessen the dark count rate. Experimental results demonstrate that the prototype fabricated with a standard HV-CMOS process gets rid of afterpulses and offers a reduced dark count probability by applying the proposed modes of operation. The detector exhibits a dynamic range of 15 bits with short gated"on" periods of 10ns and a reverse bias overvoltage of 1.0V.
Resumo:
An analysis of silicon on insulator structures obtained by single and multiple implants by means of Raman scattering and photoluminescence spectroscopy is reported. The Raman spectra obtained with different excitation powers and wavelengths indicate the presence of a tensile strain in the top silicon layer of the structures. The comparison between the spectra measured in both kinds of samples points out the existence in the multiple implant material of a lower strain for a penetration depth about 300 nm and a higher strain for higher penetration depths. These results have been correlated with transmission electron microscopy observations, which have allowed to associate the higher strain to the presence of SiO2 precipitates in the top silicon layer, close to the buried oxide. The found lower strain is in agreement with the better quality expected for this material, which is corroborated by the photoluminescence data.
Resumo:
Background: The goal of the present study was to retrospectively analyze our series of parasagittal meningiomas, treated by either single or combined therapies (surgery and/or SRS and FSRT), in order to determine the factors that influence patient outcome. Methods: Between January 1999 and May 2007, 37 parasagittal meningiomas were treated in our center. We compared the outcome of the parasagittal meningiomas in relation to the treatment and adjuvant treatment given, their location along the SSS, their volume, their histological and resection grade as well as the patient's sex and age to understand which factors influenced their natural history. Findings: Median follow-up was 6.7 years (2.4-12 years). Tumor grades and Simpson resection grade were distributed evenly along the SSS. The actuarial overall tumor control rate was 65.9%. Regression analysis showed, that the tumor histological grade and the Simpson resection grade were two significant factors in determining the tumor control (p<0.002 and p<0.008). Location along the SSS showed a lower control rate in the posterior third (p<0.002). Sex, age and tumor volume, however, were not significant factors. Moreover, and unexpectedly, the In our series, the proportion of adjuvant treatment was much higher than in former described series (39% vs 7%) but with similar control rate and lower morbidity and mortality. Conclusions: In our series, histological grade and Simpson grade are independent factors for recurrence and tumor control. Interestingly, location in the posterior third of the SSS seems to be another independent factor for recurrence. In order to avoid major morbidities related to surgery we advocate earlier use of adjuvant therapies for higher histological grade tumors and for tumors located at the posterior portion of the SSS, but definitive conclusions might warrant a larger series.
Resumo:
In this paper we show that the orthorhombic phase of FeSi2 (stable at room temperature) displays a sizable anisotropy in the infrared spectra, with minor effects in the Raman data too. This fact is not trivial at all, since the crystal structure corresponds to a moderate distortion of the fluorite symmetry. Our analysis is carried out on small single crystals grown by flux transport, through polarization-resolved far-infrared reflectivity and Raman measurements. Their interpretation has been obtained by means of the simulated spectra with tight-binding molecular dynamics.
Resumo:
We obtained Ba3Yb(BO3)3 single crystals by the flux method with solutions of the BaB2O4Na2OYb2O3 system. The evolution of the cell parameters with temperature shows a slope change at temperatures near 873 K, which may indicate a phase transition that is not observed by changes appearing in the x-ray powder patterns or by differential thermal analysis (DTA). The evolution of the diffraction patterns with the temperature shows incongruent melting at temperatures higher than 1473 K. DTA indicates that there is incongruent melting and this process is irreversible. Ba3Yb(BO3)3 has a wide transparency window from 247 to 3900 nm. We recorded optical absorption and emission spectra at room and low temperature, and we determined the splitting of Yb3+ ions. We used the reciprocity method to calculate the maximum emission cross section of 0.28 10-20 cm2 at 966 nm. The calculated lifetime of Yb3+ in Ba3Yb(BO3)3 is trad = 2.62 ms, while the measured lifetime is t = 3.80 ms.
Resumo:
Single-valued solutions for the case of two-sided market games without product differentiation, also known as Böhm-Bawerk horse market games, are analyzed. The nucleolus is proved to coincide with the tau-value, and is thus the midpoint of the core. Moreover a characterization of this setof games in terms of the assignment matrix is provided.
Resumo:
[cat] En aquest treball caracteritzem les solucions puntuals de jocs cooperatius d'utilitat transferible que compleixen selecció del core i monotonia agregada. També mostrem que aquestes dues propietats són compatibles amb la individualitat racional, la propietat del jugador fals i la propietat de simetria. Finalment, caracteritzem les solucions puntuals que compleixen les cinc propietats a l'hora.
Resumo:
Adult-type rhabdomyosarcoma (RMS) has been classically defined as a pleomorphic sarcoma with desmin expression occurring in adult patients. To reevaluate this entity, we analyzed a series of 57 cases using immunohistochemistry for desmin, myogenin, alpha smooth muscle actin, h-caldesmon, pankeratin AE1/AE3, epithelial membrane antigen (EMA), S100 protein, CD34, MDM2, and CDK4. In this series, there were 36 men and 21 women aged from 22 to 87 years (median: 59). Tumors were mainly located in the lower limbs (27 cases), trunk wall (15 cases), and upper limbs (10 cases). Most tumors were deeply located (51/54) with a size from 1 to 30 cm (median: 8 cm). Cases were classified in 3 histologic categories: spindle cell RMS (25 cases), pleomorphic RMS (16 cases), and mixed type (16 cases). Forty-one tumors were grade 3 and 16 grade 2. Immunohistochemistry showed that every case was positive for desmin and myogenin. Alpha smooth muscle actin was positive in 21%, pankeratin AE1/AE3 in 20%, and CD34 in 13.2%. Treatment modalities and follow-up were available in 46 cases. Median follow-up was 60.9 months. Eight patients developed a local recurrence and 16 a distant metastasis with a 5-year overall survival rate of 52.6% and a 5-year metastasis-free survival of 62.9%. The only predictive factor for metastasis was histologic grade. In conclusion, adult-type RMS is a rare sarcoma occurring mainly in the extremities and trunk wall with 2 main histologic patterns, spindle cell, and pleomorphic patterns, which represent the end of the spectrum of a single entity.