Thermoelectric Control of Deep UV LED to Improve Optical Performance

A thermoelectric control system using thermoelectric cooler devices (TEC) combined with an aluminum heat dissipater and a fan heat extractor allows improving considerably the optical performance of deep UV LEDs (285 nm) operating at desired temperatures. A proportional, integral, and differential controller (PID) control technique was implemented to control the voltage in the TEC devices, and therefore, the desired range of temperatures can be achieved. The PID parameters are obtained with computational simulations based on physical models and experimental data recordings of the temperature, using a thermistor sensor for the temperature measurements and SiC photodiode with UV enhanced system for the optical power measurements. The experimental data show that decreasing the temperature of the UV-C LED light source using a TEC increases the optical output power, while it has been shown that the lifetime of the LED devices can be improved

Wavelet Design for Automatic Real-Time Eye Blink Detection and Recognition in EEG Signals

The blinking of an eye can be detected in electroencephalographic (EEG) recordings and can be understood as a useful control signal in some information processing tasks. The detection of a specific pattern associated with the blinking of an eye in real time using EEG signals of a single channel has been analyzed. This study considers both theoretical and practical principles enabling the design and implementation of a system capable of precise real-time detection of eye blinks within the EEG signal. This signal or pattern is subject to considerable scale changes and multiple incidences. In our proposed approach, a new wavelet was designed to improve the detection and localization of the eye blinking signal. The detection of multiple occurrences of the blinking perturbation in the recordings performed in real-time operation is achieved with a window giving a time-limited projection of an ongoing analysis of the sampled EEG signal

The one dimensional Hydrogen atom revisited

The one dimensional Schroedinger hydrogen atom is an interesting mathematical and physical problem to study bound states, eigenfunctions and quantum degeneracy issues. This 1D physical system gave rise to some intriguing controversy over more than four decades. Presently, still no definite consensus seems to have been reached. We reanalyzed this apparently controversial problem, approaching it from a Fourier transform representation method combined with some fundamental (basic) ideas found in self-adjoint extensions of symmetric operators. In disagreement with some previous claims, we found that the complete Balmer energy spectrum is obtained together with an odd parity set of eigenfunctions. Closed form solutions in both coordinate and momentum spaces were obtained. No twofold degeneracy was observed as predicted by the degeneracy theorem in one dimension, though it does not necessarily have to hold for potentials with singularities. No ground state with infinite energy exists since the corresponding eigenfunction does not satisfy the Schroedinger equation at the origin.Comment: Accepted for publication in the Canadian Journal of Physics, July 28th, 200

PNPLA3 gene polymorphism is associated with predisposition to and severity of alcoholic liver disease

The genetic polymorphism with an isoleucine-to-methionine substitution at position 148 (rs738409 C>G) in the patatin-like phospholipase domain protein 3 (PNPLA3) gene confers risk of steatosis. PNPLA3 polymorphism is shown to be associated with alcoholic liver disease (ALD). We performed a systematic review and meta-analysis to examine association of this genetic polymorphism with ALD spectrum and its severity.METHODS:Medline, Embase, and Cochrane Library were searched for studies on association of PNPLA3 polymorphism and ALD spectrum: alcoholic fatty liver (AFL), alcoholic liver injury (ALI), alcoholic cirrhosis (AC), and hepatocellular carcinoma (HCC). Pooled data are reported as odds ratio (OR) with 95% confidence interval. Heterogeneity was assessed using the I 2 statistics and publication bias using Egger's test and Begg and Mazumdar's test. Individual participant data obtained from five studies were used for subgroup analyses.RESULTS:Among 10 studies included in this pooled analysis, compared with controls, OR for rs738409 CG and GG among ALI patients was 1.45 (1.24-1.69) and 2.22 (1.50-3.28), respectively, compared with CC. Respective OR among AC patients was 2.09 (1.79-2.44) and 3.37 (2.49-4.58) and among AC patients with HCC was 2.87 (1.61-5.10) and 12.41 (6.99-22.03). Data for AFL were inconsistent. Among ALD patients, OR of CG and GG genotypes was 2.62 (1.73-3.97) and 8.45 (2.52-28.37), respectively, for AC compared with fatty liver (FL) patients. Similar OR for AC compared with ALI was 1.98 (1.24-3.17) and 3.86 (1.18-12.60). The OR for CG and GG genotypes among AC patients for HCC occurrence was 1.43 (0.76-2.72) and 2.81 (1.57-5.01), respectively. Individual participant data analysis showed age to predispose to AC among ALI patients.CONCLUSIONS:PNPLA3 genetic polymorphism (rs738409 C>G) is associated with increased risk for the entire spectrum of ALD among drinkers including ALI, AC, and HCC. Studies are needed to clarify association of PNPLA3 polymorphism and steatosis in alcoholics. PNPLA3 gene may potentially be a therapeutic target in ALD

Common themes in centriole and centrosome movements.

addresses: School of Life Sciences, Oxford Brookes University, Gipsy Lane, Oxford, OX3 0BP, UK.Copyright © 2011 Elsevier. NOTICE: this is the author’s version of a work that was accepted for publication in Trends in Cell Biology. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Trends in Cell Biology, 2011, Vol. 21, Issue 1, pp. 57 – 66 DOI: 10.1016/j.tcb.2010.09.004Centrioles are found in nearly all eukaryotic cells and are required for growth and maintenance of the radial array of microtubules, the mitotic spindle, and cilia and flagella. Different types of microtubule structures are often required at different places in a given cell; centrioles must move around to nucleate these varied structures. Here, we draw together recent data on diverse centriole movements to decipher common themes in how centrioles move. Par proteins establish and maintain the required cellular asymmetry. The actin cytoskeleton facilitates movement of multiple basal bodies. Microtubule forces acting on the cell cortex, and nuclear-cytoskeletal links, are important for positioning individual centrosomes, and during cell division. Knowledge of these common mechanisms can inform the study of centriole movements across biology

The Mother Centriole Plays an Instructive Role in Defining Cell Geometry

Centriole positioning is a key step in establishment and propagation of cell geometry, but the mechanism of this positioning is unknown. The ability of pre-existing centrioles to induce formation of new centrioles at a defined angle relative to themselves suggests they may have the capacity to transmit spatial information to their daughters. Using three-dimensional computer-aided analysis of cell morphology in Chlamydomonas, we identify six genes required for centriole positioning relative to overall cell polarity, four of which have known sequences. We show that the distal portion of the centriole is critical for positioning, and that the centriole positions the nucleus rather than vice versa. We obtain evidence that the daughter centriole is unable to respond to normal positioning cues and relies on the mother for positional information. Our results represent a clear example of “cytotaxis” as defined by Sonneborn, and suggest that centrioles can play a key function in propagation of cellular geometry from one generation to the next. The genes documented here that are required for proper centriole positioning may represent a new class of ciliary disease genes, defects in which would be expected to cause disorganized ciliary position and impaired function

Conceptualizing historical organization studies

© 2016 Academy of Management Review. The promise of a closer union between organizational and historical research has long been recognized. However, its potential remains unfulfilled: The authenticity of theory development expected by organization studies and the authenticity of historical veracity required by historical research place exceptional conceptual and empirical demands on researchers. We elaborate the idea of historical organization studies-organizational research that draws extensively on historical data, methods, and knowledge to promote historically informed theoretical narratives attentive to both disciplines. Building on prior research, we propose a typology of four differing conceptions of history in organizational research: History as evaluating, explicating, conceptualizing, and narrating. We identify five principles of historical organization studies-dual integrity, pluralistic understanding, representational truth, context sensitivity, and theoretical fluency-and illustrate our typology holistically from the perspective of institutional entrepreneurship. We explore practical avenues for a creative synthesis, drawing examples from social movement research and microhistory. Historically informed theoretical narratives whose validity derives from both historical veracity and conceptual rigor afford dual integrity that enhances scholarly legitimacy, enriching understanding of historical, contemporary, and future-directed social realities

Filters and Filter Design

En el presente texto se señala la importancia que adquiere el Procesamiento Digital de Imágenes en el área de la medicina. Para esto, el texto explica el desarrollo y uso de este tipo de procesamiento de imágenes, lo compara con otros tipos de procesamiento y expone los posibles usos que puede dar la medicina al Procesamiento Digital de Imágenes

Point Operations

En el presente texto se señala la importancia que adquiere el Procesamiento Digital de Imágenes en el área de la medicina. Para esto, el texto explica el desarrollo y uso de este tipo de procesamiento de imágenes, lo compara con otros tipos de procesamiento y expone los posibles usos que puede dar la medicina al Procesamiento Digital de Imágenes