The Use of a Lock-In Amplifier to Stabilize the Frequency of a Laser Diode

We have designed, constructed, and tested a lock-in amplifier with readily available electronic components and homebuilt analog circuits. Its performance is comparable to that of a commercial unit, but it costs significantly less and is much more compact. The various components of our lock-in amplifier are discussed and the basic principles behind the function and operation of this versatile device are explained. We have also assembled a laser system and used the output signal of our lock-in amplifier in a negative feedback loop to stabilize the frequency of our laser to an atomic reference frequency

Case-base maintenance with multi-objective evolutionary algorithms.

Case-Base Reasoning is a problem-solving methodology that uses old solved problems, called cases, to solve new problems. The case-base is the knowledge source where the cases are stored, and the amount of stored cases is critical to the problem-solving ability of the Case-Base Reasoning system. However, when the case-base has many cases, then performance problems arise due to the time needed to find those similar cases to the input problem. At this point, Case-Base Maintenance algorithms can be used to reduce the number of cases and maintain the accuracy of the Case-Base Reasoning system at the same time. Whereas Case-Base Maintenance algorithms typically use a particular heuristic to remove (or select) cases from the case-base, the resulting maintained case-base relies on the proportion of redundant and noisy cases that are present in the case-base, among other factors. That is, a particular Case-Base Maintenance algorithm is suitable for certain types of case-bases that share some indicators, such as redundancy and noise levels. In the present work, we consider Case-Base Maintenance as a multi-objective optimization problem, which is solved with a Multi-Objective Evolutionary Algorithm. To this end, a fitness function is introduced to measure three different objectives based on the Complexity Profile model. Our hypothesis is that the Multi-Objective Evolutionary Algorithm performing Case-Base Maintenance may be used in a wider set of case-bases, achieving a good balance between the reduction of cases and the problem-solving ability of the Case-Based Reasoning system. Finally, from a set of the experiments, our proposed Multi-Objective Evolutionary Algorithm performing Case-Base Maintenance shows regularly good results with different sets of case-bases with different proportion of redundant and noisy cases

A genome-wide 20 K citrus microarray for gene expression analysis

<p>Abstract</p> <p>Background</p> <p>Understanding of genetic elements that contribute to key aspects of citrus biology will impact future improvements in this economically important crop. Global gene expression analysis demands microarray platforms with a high genome coverage. In the last years, genome-wide EST collections have been generated in citrus, opening the possibility to create new tools for functional genomics in this crop plant.</p> <p>Results</p> <p>We have designed and constructed a publicly available genome-wide cDNA microarray that include 21,081 putative unigenes of citrus. As a functional companion to the microarray, a web-browsable database <abbrgrp><abbr bid="B1">1</abbr></abbrgrp> was created and populated with information about the unigenes represented in the microarray, including cDNA libraries, isolated clones, raw and processed nucleotide and protein sequences, and results of all the structural and functional annotation of the unigenes, like general description, BLAST hits, putative Arabidopsis orthologs, microsatellites, putative SNPs, GO classification and PFAM domains. We have performed a Gene Ontology comparison with the full set of Arabidopsis proteins to estimate the genome coverage of the microarray. We have also performed microarray hybridizations to check its usability.</p> <p>Conclusion</p> <p>This new cDNA microarray replaces the first 7K microarray generated two years ago and allows gene expression analysis at a more global scale. We have followed a rational design to minimize cross-hybridization while maintaining its utility for different citrus species. Furthermore, we also provide access to a website with full structural and functional annotation of the unigenes represented in the microarray, along with the ability to use this site to directly perform gene expression analysis using standard tools at different publicly available servers. Furthermore, we show how this microarray offers a good representation of the citrus genome and present the usefulness of this genomic tool for global studies in citrus by using it to catalogue genes expressed in citrus globular embryos.</p

WASPSS: A Clinical Decision Support System for Antimicrobial Stewardship

The increase of infections caused by resistant bacteria has become one of the major health-care problems worldwide. The creation of multidisciplinary teams dedicated to the implementation of antimicrobial stewardship programmes (ASPs) is encouraged by all clinical institutions to cope with this problem. In this chapter, we describe the Wise Antimicrobial Stewardship Program Support System (WASPSS), a CDSS focused on providing support for ASP teams. WASPSS gathers the required information from other hospital systems in order to provide decision support in antimicrobial stewardship from both patient-centered and global perspectives. To achieve this, it combines business intelligence techniques with a rule-based inference engine to integrate the data and knowledge required in this scenario. The system provides functions such as alerts, recommendations, antimicrobial prescription support and global surveillance. Furthermore, it includes experimental modules for improving the adoption of clinical guidelines and applying prediction models related with antimicrobial resistance. All these functionalities are provided through a multi-user web interface, personalized for each role of the ASP team

Delayed Corneal Epithelial Healing after Intravitreal Bevacizumab: A Clinical and Experimental Study

Purpose: To report corneal epithelial defects (CEDs) and delayed epithelial healing after intravitreal bevacizumab (IVB) injection and to describe delayed corneal epithelial healing with topical administration of bevacizumab in an experimental rabbit model. Methods: A retrospective chart review was performed on 850 eyes of 850 patients with neovascular eye disease and diabetic macular edema who had received 1.25 to 2.5 mg IVB. In the experimental arm of the study, photorefractive keratectomy was used to create a 3 mm CED in the right eyes of 18 New Zealand rabbits which were then randomized to three equal groups. All rabbits received topical antibiotics, additionally those in group A received topical bevacizumab and animals in group B were treated with topical corticosteroids. The rate of epithelial healing was assessed at different time points using slitlamp photography. Results: In the clinical study, seven eyes of seven subjects developed CEDs the day after IVB injection. All of these eyes had preexisting corneal edema. The healing period ranged from 3 to 38 days (average 11 days) despite appropriate medical management. In the experimental study, topical bevacizumab and corticosteroids both significantly hindered corneal epithelial healing at 12 and 24 hours. Conclusion: Bevacizumab was demonstrated to cause CEDs in clinical settings. Moreover, corneal epithelial healing was delayed by topical application of bevacizumab, in the experimental model. These short-term results suggest that corneal edema may be considered as a risk factor for epithelial defects after IVB

Recombination reduction on lead halide perovskite solar cells based on low temperature synthesized hierarchical TiO2 nanorods

Intensive research on the electron transport material (ETM) has been pursued to improve the efficiency of perovskite solar cells (PSCs) and decrease their cost. More importantly, the role of the ETM layer is not yet fully understood, and research on new device architectures is still needed. Here, we report the use of three-dimensional (3D) TiO2 with a hierarchical architecture based on rutile nanorods (NR) as photoanode material for PSCs. The proposed hierarchical nanorod (HNR) films were synthesized by a two-step low temperature (180 °C) hydrothermal method, and consist of TiO2 nanorod trunks with optimal lengths of 540 nm and TiO2 nanobranches with lengths of 45 nm. Different device configurations were fabricated with TiO2 structures (compact layer, NR and HNR) and CH3NH3PbI3, using different synthetic routes, as the active material. PSCs based on HNR-CH3NH3PbI3 achieved the highest power conversion efficiency compared to PSCs with other TiO2 structures. This result can be ascribed mainly to lower charge recombination as determined by impedance spectroscopy. Furthermore, we have observed that the CH3NH3PbI3 perovskite deposited by the two-step route shows higher efficiency, surface coverage and infiltration within the structure of 3D HNR than the one-step CH3NH3PbI3−xClx perovskite.This work was supported by the Universitat Jaume I (project 12I361.01/1), the Spanish MINECO (project MAT2013-47192- C3-1-R), CONACYT-México (project CB-2010/153270) and UNAM (PAPIIT-IN1030

Bioinformatic analysis of gene regulation in Geobacter sulfurreducens

Background Geobacteraceae are a family of microorganisms from the delta subdivision of Proteobacteria. They have potential for environmental bioremediation and electricity generation. In this presentation, we describe our recent bioinformatic analyses of gene regulation in Geobacter sulfurreducens, a model representative of this family. Results and conclusion We have developed an online database, GSEL (Geobacter Sequence Elements), which compiles regulatory information for G. sulfurreducens. We have recently completed the development of a new, significantly expanded and updated, relational version 2 of the GSEL database and its accompanying online query system, which compiles manually curated information on operon organization and transcription regulatory elements in the genome of G. sulfurreducens. GSEL v. 2 incorporates a graphical browser and provides significantly expanded search capabilities. It also includes new information on predicted and/or experimentally validated genome regulatory sites and provides links to information from microarray experiments stored in public gene expression databases, and to original publications describing how particular regulatory interactions were identified. Using sequence and gene expression analyses, we investigated target genes and promoters regulated by RpoN, an alternative RNA polymerase sigma factor, which regulates a variety of important cellular processes in G. sulfurreducens. Our current studies are focusing on an investigation of several transcription regulatory systems involved in RpoN-dependent regulatory pathways. We have investigated target regulatory sites for an enhancer binding protein, PilR, which participates in RpoN-dependent transcriptional regulation of the pilA gene encoding structural pilin. We predicted multiple PilR-regulated sites upstream of operons related to biosynthesis, assembly, and function of pili and flagella, type II secretory pathways, and cell wall biogenesis. We also investigated sequence changes and molecular classification of the TetR family of transcriptional regulators. In G. sulfurreducens, we identified RpoN-regulated promoters upstream of several operons containing tetR family genes. The genome of G. sulfurreducens contains nine tetR family genes. Some of them are located upstream of operons encoding functionally important c-type cytochromes. In order to better understand the roles of TetR family members in the ability of Geobacteraceae to participate in electron transfer, we investigated phylogenetic relationships among TetR proteins in Geobacteraceae and in other microbial species. We identified their conserved and variable domains, which may be important for the diversity of their functional roles, and classified them into subgroups based on sequence similarities

Developing capacity in health informatics in a resource poor setting: lessons from Peru

The public sectors of developing countries require strengthened capacity in health informatics. In Peru, where formal university graduate degrees in biomedical and health informatics were lacking until recently, the AMAUTA Global Informatics Research and Training Program has provided research and training for health professionals in the region since 1999. The Fogarty International Center supports the program as a collaborative partnership between Universidad Peruana Cayetano Heredia in Peru and the University of Washington in the United States of America. The program aims to train core professionals in health informatics and to strengthen the health information resource capabilities and accessibility in Peru. The program has achieved considerable success in the development and institutionalization of informatics research and training programs in Peru. Projects supported by this program are leading to the development of sustainable training opportunities for informatics and eight of ten Peruvian fellows trained at the University of Washington are now developing informatics programs and an information infrastructure in Peru. In 2007, Universidad Peruana Cayetano Heredia started offering the first graduate diploma program in biomedical informatics in Peru