Measuring Device and Material ZT in a Thin-Film Si-Based Thermoelectric Microgenerator.

Thermoelectricity (TE) is proving to be a promising way to harvest energy for small applications and to produce a new range of thermal sensors. Recently, several thermoelectric generators (TEGs) based on nanomaterials have been developed, outperforming the efficiencies of many previous bulk generators. Here, we presented the thermoelectric characterization at different temperatures (from 50 to 350 K) of the Si thin-film based on Phosphorous (n) and Boron (p) doped thermocouples that conform to a planar micro TEG. The thermocouples were defined through selective doping by ion implantation, using boron and phosphorous, on a 100 nm thin Si film. The thermal conductivity, the Seebeck coefficient, and the electrical resistivity of each Si thermocouple was experimentally determined using the in-built heater/sensor probes and the resulting values were refined with the aid of finite element modeling (FEM). The results showed a thermoelectric figure of merit for the Si thin films of z T = 0.0093, at room temperature, which was about 12% higher than the bulk Si. In addition, we tested the thermoelectric performance of the TEG by measuring its own figure of merit, yielding a result of ZT = 0.0046 at room temperature.

Thermoelectric Photosensor Based on Ultrathin Single-Crystalline Si Films †.

Ultrathin Si films have a reduced thermal conductivity in comparison to Si bulk due to phonon scattering at the surfaces. Furthermore, the small thickness guarantees a reduced thermal mass (in the µJ/K range), which opens up the possibility of developing thermal sensors with a high sensitivity. Based on these premises, a thermoelectric (TE) microsensor based on ultrathin suspended Si films was developed and used as a thermal photosensor. The photoresponse of the device was evaluated with an argon laser (λ = 457 nm) with a variable power ranging from 0 to 10 mW in air at atmospheric pressure, with laser diodes at 406 nm, 520 nm and 638 nm wavelengths, and fixed powers in high vacuum conditions. The responsivity per unit area, response time (τ) and detectivity (D*) of the device were determined in air at ambient pressure, being 2.6 × 107 V/Wm², ~4.3 ms and 2.86 × 10 7   c m H z ( 1 / 2 ) W - 1 , respectively. Temperature differences up to 30 K between the central hot region and the Si frame were achieved during open-circuit voltage measurements, with and without laser diodes. During illumination, the photogeneration of carriers caused a slight reduction of the Seebeck coefficient, which did not significantly change the sensitivity of the device. Moreover, the measurements performed with light beam chopped at different frequencies evidenced the quick response of the device. The temperature gradients applied to the thermoelectric Si legs were corrected using finite element modeling (FEM) due to the non-flat temperature profile generated during the experiments.

Polymorphisms associated with everolimus pharmacokinetics, toxicity and survival in metastatic breast cancer.

PURPOSE: Metastatic breast cancer (MBC) progressing after endocrine therapy frequently activates PI3K/AKT/mTOR pathway. The BOLERO-2 trial showed that everolimus-exemestane achieves increased progression free survival (PFS) compared with exemestane. However, there is great inter-patient variability in toxicity and response to exemestane-everolimus treatment. The objective of this study was to perform an exploratory study analyzing the implication of single nucleotide polymorphisms (SNPs) on outcomes from this treatment through a pharmacogenetic analysis. PATIENTS AND METHODS: Blood was collected from 90 postmenopausal women with hormone receptor-positive, HER2-negative MBC treated with exemestane-everolimus following progression after prior treatment with a non-steroidal aromatase inhibitor. Everolimus pharmacokinetics was measured in 37 patients. Twelve SNPs in genes involved in everolimus pharmacokinetics and pharmacodynamics were genotyped and associations assessed with drug plasma levels, clinically relevant toxicities (non-infectious pneumonitis, mucositis, hyperglycemia and hematological toxicities), dose reductions or treatment suspensions due to toxicity, progression free survival (PFS) and overall survival. RESULTS: We found that CYP3A4 rs35599367 variant (CYP3A4*22 allele) carriers had higher everolimus blood concentration compared to wild type patients (P = 0.019). ABCB1 rs1045642 was associated with risk of mucositis (P = 0.031), while PIK3R1 rs10515074 and RAPTOR rs9906827 were associated with hyperglycemia and non-infectious pneumonitis (P = 0.016 and 0.024, respectively). Furthermore, RAPTOR rs9906827 was associated with PFS (P = 0.006). CONCLUSIONS: CYP3A4*22 allele influenced plasma concentration of everolimus and several SNPs in PI3K/AKT/mTOR pathway genes were associated with treatment toxicities and prognosis. These results require replication, but suggest that germline variation could influence everolimus outcomes in MBC.

Simultaneous nanocalorimetry and fast XRD measurements to study the silicide formation in Pd/a-Si bilayers.

The use of a membrane-based chip nanocalorimeter in a powder diffraction beamline is described. Simultaneous wide-angle X-ray scattering and scanning nanocalorimetric measurements are performed on a thin-film stack of palladium/amorphous silicon (Pd/a-Si) at heating rates from 0.1 to 10 K s(-1). The nanocalorimeter works under a power-compensation scheme previously developed by the authors. Kinetic and structural information of the consumed and created phases can be obtained from the combined techniques. The formation of Pd2Si produces a broad calorimetric peak that contains overlapping individual processes. It is shown that Pd consumption precedes the formation of the crystalline Pd2Si phase and that the crystallite size depends on the heating rate of the experiment.

Highly efficient crossing structure for silicon-on-insulator waveguides.

A compact waveguide crossing structure with low transmission losses and negligible crosstalk is demonstrated for silicon-on-insulator circuits. The crossing structure is based on a mode expander optimized by means of a genetic algorithm leading to transmission losses lower than 0.2 dB and crosstalk and reflection losses below 40 dB in a broad bandwidth of 20 nm. Furthermore, the resulting crossing structure has a footprint of only 6x6 microm(2) and does not require any additional fabrication steps.

Amputacion digital de Syme / Syme`s method for the amputation of a phalanx

Introduccion: La amputacion digital de Syme fue descrita en 1874 por Hukill y dada a conocer en 1933 por Lapidus; en la bibliografia no abundan sus presentaciones y hay pocas publicaciones de su ejecucion. Materiales y metodos: Se presentan 28 cirugias efectuadas en 16 pacientes con una edad promedio de 47,5 años, efectuadas y seguidas desde 1989 hasta 2003, con una media del seguimiento de 2,5 años. La cirugia consiste en abordar la ultima falange de un dedo del pie, se reseca la matriz ungular en forma completa, se escinde la mitad distal de la falange distal, se rebate hacia dorsal el colgajo tallado y se lo sutura en un plano. Resultados: Hemos obtenido buenos resultados, en cuanto a la confeccion de la tecnica y el seguimiento de los pacientes. Describimos una prueba para la evaluacion de la tecnica. No hemos tenido complicaciones de indole biomecanica ni estetica. Conclusiones: Promovemos el uso de esta tecnica siempre que se haya efectuado la eleccion correcta del paciente de acuerdo con la patologia que lo aqueja