A new modulation technique for high data rate low power UWB wireless optical communication in implantable biotelemetry systems

We report on the development of a novel modulation technique for UWB wireless optical communication systems for application in a transcutaneous biotelemetry. The solution, based on the generation of short laser pulses, allows for a high data rate link whilst achieving a significant power reduction (energy per bit) compared to the state-of-the-art. These features make this particularly suitable for emerging biomedical applications such as implantable neural/biosensor systems. The relatively simple architecture consists of a transmitter and receiver that can be integrated in a standard CMOS technology in a compact Silicon footprint. These parts include circuits for bias and drive current generation, conditioning and processing, optimised for low-volt age/low-power operation. Preliminary experimental findings validate the new paradigm and show good agreement with expected results. The complete system achieves a BER less than 10-7, with maximum data rate of 125Mbps and estimated total power consumption of less than 3mW

Analysis of the inner collection efficiency in hybrid silicon solar cells

The collection of photogenerated carriers in hybrid silicon solar cells structures were determined by the DICE (dynamic inner collection efficiency) technique. The hybrid solar cells have a microcrystalline n-type emitter and a crystalline p-type base. Cells with amorphous buffers of several thickness and p+ back surface field microcrystalline layers were also studied. Spectral response and reflectivity were measured for each sample in order to obtain the internal spectral response or quantum efficiency. These data are the input to DICE analysis, together with the optical parameters of each layer. We observed that the emitter thickness is the most important parameter which defines the solar cell photovoltaic behavior. DICE profiles show that cells with emitter thickness of 80 Å have better collection efficiency than cells with higher thickness values mainly near the surface (until 1 μm below the ITO/microcrystalline interface). The efficacy of the back surface field can be observed with this technique by determining the DICE values near the back metalization and the minority carriers diffusion length can be calculated using the DICE profile in the bulk.The collection of photogenerated carriers in hybrid silicon solar cells structures were determined by the DICE (dynamic inner collection efficiency) technique. The hybrid solar cells have a microcrystalline n-type emitter and a crystalline p-type base. Cells with amorphous buffers of several thickness and p+ back surface field microcrystalline layers were also studied. Spectral response and reflectivity were measured for each sample in order to obtain the internal spectral response or quantum efficiency. These data are the input to DICE analysis, together with the optical parameters of each layer. We observed that the emitter thickness is the most important parameter which defines the solar cell photovoltaic behavior. DICE profiles show that cells with emitter thickness of 80 Å have better collection efficiency than cells with higher thickness values mainly near the surface (until 1 μm below the ITO/microcrystalline interface). The efficacy of the back surface field can be observed with this technique by determining the DICE values near the back metalization and the minority carriers diffusion length can be calculated using the DICE profile in the bulk.The collection of photogenerated carriers in hybrid silicon solar cells structures were determined by the DICE (dynamic inner collection efficiency) technique. The hybrid solar cells have a microcrystalline n-type emitter and a crystalline p-type base. Cells with amorphous buffers of several thickness and p+ back surface field microcrystalline layers were also studied. Spectral response and reflectivity were measured for each sample in order to obtain the internal spectral response or quantum efficiency. These data are the input to DICE analysis, together with the optical parameters of each layer. We observed that the emitter thickness is the most important parameter which defines the solar cell photovoltaic behavior. DICE profiles show that cells with emitter thickness of 80 Å have better collection efficiency than cells with higher thickness values mainly near the surface (until 1 μm below the ITO/microcrystalline interface). The efficacy of the back surface field can be observed with this technique by determining the DICE values near the back metalization and the minority carriers diffusion length can be calculated using the DICE profile in the bulk

Alessandro Mancuso, Altre persone: Antropologia, visioni del mondo e ontologie indigene, Milano, Mimesis, 2018, pp. 307

Book review of Alessandro Mancuso, Altre persone: Antropologia, visioni del mondo e ontologie indigene, Milano, Mimesis, 2018, pp. 307.Recensione di Alessandro Mancuso, Altre persone: Antropologia, visioni del mondo e ontologie indigene, Milano, Mimesis, 2018, pp. 307

A new optical UWB modulation technique for 250Mbps wireless link in implantable biotelemetry systems

We propose a new UWB modulation technique for wireless optical communications in transcutaneous biotelemetry. The solution, based on the generation of sub-nanoseconds laser pulses, allows for a high data rate link whilst achieving a significant power reduction (energy per bit) compared to the state-ofthe- art. These features make this particularly suitable for emerging biomedical applications such as implantable neural/biosensor systems. The relatively simple architecture consists of a transmitter and receiver that can be integrated in a standard CMOS technology in a compact Silicon footprint (lower than 1mm^2 in a 0.18μm technology). These parts, optimised for low-voltage/low-power operation, include coding and decoding digital systems, biasing and driving analogue circuits for laser pulse generation and photodiode signal conditioning. Experimental findings with prototype PCBs have validated the new paradigm showing the system capabilities to achieve a BER less than 10^-9 with data rate up to 250Mbps and estimated total power consumption lower than 5mW

Sunrise to sunset optimization of thin film antireflective coatings for encapsulated, planar silicon solar cells

We present an approach for the optimization of thin film antireflective coatings for encapsulated planar silicon solar cells in which the variations in the incident spectra and angle of incidence (AOI) over a typical day are fully considered. Both the angular and wavelength dependences of the reflectance from the surface, absorptance within the coating, and transmittance into the device are calculated for both single- and doublelayer antireflection coatings with and without thin silicon oxide passivation layers. These data are then combined with spectral data as a function of time of day and internal quantum efficiency to estimate the average short-circuit current produced by a fixed solar cell during a day. This is then used as a figure of merit for the optimization of antireflective layer thicknesses for modules placed horizontally at the equator and on a roof in the UK. Our results indicate that only modest gains in average short-circuit current could be obtained by optimizing structures for sunrise to sunset irradiance rather than AM15 at normal incidence, and fabrication tolerances and uniformities are likely to be more significant. However, we believe that this overall approach to optimization will be of increasing significance for new, potentially asymmetric, antireflection schemes such as those based on subwavelength texturing or other photonic or plasmonic technologies currently under development especially when considered in combination with modules fixed at locations and directions that result in asymmetric spectral conditions

Epithelial and stromal remodelling following femtosecond laser–assisted stromal lenticule addition keratoplasty (SLAK) for keratoconus

The purpose of this study was to evaluate corneal epithelium and stromal remodelling with anterior segment optical coherence tomography in patients who have undergone stromal lenticule addition keratoplasty (SLAK) for advanced keratoconus. This was a prospective non-comparative observational study. Fifteen eyes of 15 patients with advanced keratoconus underwent implantation with a cadaveric, donor negative meniscus-shaped intrastromal lenticule, produced with a femtosecond laser, into a stromal pocket dissected in the recipient cornea at a depth of 120 μm. Simulated keratometry, central corneal thickness (CTT), corneal thinnest point (CTP), central epithelial thickness (CET), central and peripheral lenticule thickness, anterior and posterior stromal thickness were measured. Regional central corneal epithelial thickness (CET) and variations in the inner annular area (IAT) and outer annular area (OAT) were also analysed. All parameters were measured preoperatively and 1, 3, and 6 months postoperatively. The average anterior Sim-k decreased from 59.63 ± 7.58 preoperatively to 57.19 ± 6.33 D 6 months postoperatively. CCT, CTP, CET, and OAT increased and IAT decreased significantly after 1 month. All parameters appeared unchanged at 6-months except that of OAT that further increased. Lenticule thickness was stable. In conclusion we observed that SLAK reshapes the cornea by central flattening with stromal thickening and epithelial thickness restoration

O discurso de beleza de digital influencers

Com a popularização da internet e das redes sociais surgem novas configurações políticas, formas de comunicação e processos de subjetivação. Geralmente, a rede mundial de comunicação é democrática, possibilitando que grupos historicamente excluídos da mídia tradicional criem e divulguem seu conteúdo, visibilizando suas narrativas. Ressalta-se o fato de a internet estar inserida na sociedade capitalista, reproduzindo valores e estruturas de dominação característicos. Assim, cabe identificar aspectos de opressão e de empoderamento feminino, assim como sua coexistência. O objetivo deste artigo reside em lançar um olhar sobre como as mulheres se posicionam dentro do espaço online ao analisar dois vídeos do YouTube. O método utilizado foi o das intervenções psicanalíticas clínico-políticas. Conclui-se que aspectos opressores encontrados nos discursos online estão alinhados com a reafirmação de valores de consumo, enquanto o conteúdo empoderador está vinculado à inclusão e à visibilização de grupos fora dos padrões estéticos inseridos nos espaços de poder