2,629 research outputs found

    Tunable beam displacer

    Get PDF
    We report the implementation of a tunable beam displacer, composed of a polarizing beam splitter (PBS) and two mirrors, that divides an initially polarized beam into two parallel beams whose separation can be continuously tuned. The two output beams are linearly polarized with either vertical or horizontal polarization and no optical path difference is introduced between them. The wavelength dependence of the device as well as the maximum separation between the beams achievable is limited mainly by the PBS characteristics.Comment: 3 pages, 2 figure

    Ultrasound potentialities on the determination of the pesticide carbaryl using diamond electrodes

    Get PDF
    The potentiality of the use of ultrasound radiation in association with a boron-doped diamond electrode was evaluated on the voltammetric determination of the pesticide carbaryl. Improvements in the sensitivity, limit of detection and reproducibility of the measurements were observed due to both, the enhancement of mass transport and the cleaning of the electrode surface provided by ultrasound. Satisfactory recovery levels for carbaryl in pure water (96-98%) and pineapple juice (89-92%) for quiescent and sonovoltammetric methodologies were obtained. These methodologies can be alternative tools for the analyses of pesticides in fruit samples, mainly the insonated condition that improve the analytical performance and dispense intermediary cleanings of the electrode surface.CNPqFapes

    Editorial: Human rights and inequity in health access of Central American Migrants

    Get PDF
    Frontiers in Public Health is very pleased to publish this journal issue focusing on the health access of immigrants. Contributions to this journal issue include five articles that rely on different methodologies while focusing on diverse geographic world regions and target populations. This editorial summarizes these features while also highlighting the unique contributions of each article

    Depressive Symptoms and Resilience among Pregnant Adolescents: A Case-Control Study

    Get PDF
    Background. Data regarding depression and resilience among adolescents is still lacking. Objective. To assess depressive symptoms and resilience among pregnant adolescents. Method. Depressive symptoms and resilience were assessed using two validated inventories, the 10-item Center for Epidemiologic Studies Short Depression Scale (CESD-10) and the 14-item Wagnild and Young Resilience Scale (RS), respectively. A case-control approach was used to compare differences between adolescents and adults. Results. A total of 302 pregnant women were enrolled in the study, 151 assigned to each group. Overall, 56.6% of gravids presented total CESD-10 scores 10 or more indicating depressed mood. Despite this, total CESD-10 scores and depressed mood rate did not differ among studied groups. Adolescents did however display lower resilience reflected by lower total RS scores and a higher rate of scores below the calculated median (P < .05). Logistic regression analysis could not establish any risk factor for depressed mood among studied subjects; however, having an adolescent partner (OR, 2.0 CI 95% 1.06–4.0, P = .03) and a preterm delivery (OR, 3.0 CI 95% 1.43–6.55, P = .004) related to a higher risk for lower resilience. Conclusion. In light of the findings of the present study, programs oriented at giving adolescents support before, during, and after pregnancy should be encouraged

    Acute hepatic and renal toxicity assessment of Euphorbia huanchahana (Klotzsch & Garcke) Boissier (Huachangana) in Holtzman rats

    Get PDF
    Background: Euphorbia huachahana (Klotzch & Garcke) Boissier (Huachangana) (EhKGBh) has been used for over a century for medicinal purposes in the Peruvian population; however, its safety and possible toxic effects of use have not been reported. The purpose of this study was to determine the acute hepatic and renal toxicity of EhKGBh in Holtzman rats. Methods: Analytical and experimental study. The population consisted of 52 rats of both sexes weighing between 300 and 350 g divided into four groups: G1 and G2 EhKGBh groups (26 rats each) and two control groups (10 rats each). The experimental group was administered EhKGBh at a single dose of 2000 mg/kg P.O. to demonstrate toxicity during the 14-day follow-up. A daily assessment of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), total bilirubin (TBIL), and conjugated bilirubin (CBIL) was performed. Results: Evaluation of the liver tissue showed mild changes in inflammation, predominantly vascular, with small clots. Kidney tissue did not show inflammatory or necrotic changes. However, we showed differences in the weight of the rats between both groups (p < 0.004) and significant increases in TBIL (0.98–1.07 mg/dL), CBIL (0.43–0.45 mg/dL), AST (126.4–141.8 U/L), and ALP (254–298 U/L) but not ALT (39.7–41.1 U/L) (p < 0.05). Conclusion: The single dose of EhKGBh extract at 2000 mg/kg has no toxicity, and there is no change in tissue toxicity during the 14-day follow-up.Campus Lima Centr

    Incidence of Histoplasmosis in a Cohort of People with HIV: From Estimations to Reality

    Get PDF
    Among people with HIV, histoplasmosis represents an important cause of mortality. Previous studies provided estimates of the disease incidence. Here, we compared those estimates with the results obtained from a screening program implemented in Guatemala, which included histoplasmosis detection for people with HIV. To compare the results of this program with previous estimations, a literature search was performed and reports concerning histoplasmosis incidence were analyzed. The screening program enrolled 6366 patients. The overall histoplasmosis incidence in the screening program was 7.4%, which was almost double that estimated in previous studies. From 2017 to 2019, the screening program showed an upward trend in histoplasmosis cases from 6.5% to 8.8%. Histoplasmosis overall mortality among those who were newly HIV diagnosed showed a decrease at 180 days from 32.8% in 2017 to 21.2% in 2019. The screening approach using rapid diagnostic assays detects histoplasmosis cases more quickly, allowing a specific treatment to be administered, which decreases the mortality of the disease. Therefore, the use of these new techniques, especially in endemic areas of histoplasmosis, must be implemented.This work was supported by Global Action Fund for Fungal Infections and JYLAG, a charity Foundation based in Switzerland (E.A. received this funding under the proposal: “Minimising HIV deaths through rapid fungal diagnosis and better care in Guatemala”). Other contributions came from Intrahealth International and the Ministry of health in Guatemala (MSPAS).S

    Genomes-based phylogeny of the genus Xanthomonas

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>The genus <it>Xanthomonas </it>comprises several plant pathogenic bacteria affecting a wide range of hosts. Despite the economic, industrial and biological importance of <it>Xanthomonas</it>, the classification and phylogenetic relationships within the genus are still under active debate. Some of the relationships between pathovars and species have not been thoroughly clarified, with old pathovars becoming new species. A change in the genus name has been recently suggested for <it>Xanthomonas albilineans</it>, an early branching species currently located in this genus, but a thorough phylogenomic reconstruction would aid in solving these and other discrepancies in this genus.</p> <p>Results</p> <p>Here we report the results of the genome-wide analysis of DNA sequences from 989 orthologous groups from 17 <it>Xanthomonas </it>spp. genomes available to date, representing all major lineages within the genus. The phylogenetic and computational analyses used in this study have been automated in a Perl package designated Unus, which provides a framework for phylogenomic analyses which can be applied to other datasets at the genomic level. Unus can also be easily incorporated into other phylogenomic pipelines.</p> <p>Conclusions</p> <p>Our phylogeny agrees with previous phylogenetic topologies on the genus, but revealed that the genomes of <it>Xanthomonas citri </it>and <it>Xanthomonas fuscans </it>belong to the same species, and that of <it>Xanthomonas albilineans </it>is basal to the joint clade of <it>Xanthomonas </it>and <it>Xylella fastidiosa</it>. Genome reduction was identified in the species <it>Xanthomonas vasicola </it>in addition to the previously identified reduction in <it>Xanthomonas albilineans</it>. Lateral gene transfer was also observed in two gene clusters.</p

    Overexpression of wild-type human APP in mice causes cognitive déficits and pathological features unrelated to Abeta levels

    Get PDF
    Transgenic mice expressing mutant human amyloid precursor protein (APP) develop an age-dependent amyloid pathology and memory deficits, but no overt neuronal loss. Here, in mice overexpressing wild-type human APP (hAPPwt) we found an early memory impairment, particularly in the water maze and to a lesser extent in the object recognition task, but ÎČ-amyloid peptide (AÎČ42) was barely detectable in the hippocampus. In these mice, hAPP processing was basically non-amyloidogenic, with high levels of APP carboxy-terminal fragments, C83 and APP intracellular domain. A tau pathology with an early increase in the levels of phosphorylated tau in the hippocampus, a likely consequence of enhanced ERK1/2 activation, was also observed. Furthermore, these mice presented a loss of synapse-associated proteins: PSD95, AMPA and NMDA receptor subunits and phosphorylated CaMKII. Importantly, signs of neurodegeneration were found in the hippocampal CA1 subfield and in the entorhinal cortex that were associated to a marked loss of MAP2 immunoreactivity. Conversely, in mice expressing mutant hAPP, high levels of AÎČ42 were found in the hippocampus, but no signs of neurodegeneration were apparent. The results support the notion of AÎČ- independent pathogenic pathways in Alzheimer's disease

    Efecto de sustratos foliares sobre la Sigatoka Negra( Mycosphaerella fijiensis Morelet) en banano ( Musa x paradisiaca L.)Y PL\uc1TANO ( Musa acuminata Colla)

    Get PDF
    The Black Sigatoka caused by the fungus Mycosphaerella fijiensis Morelet, is the most destructive foliar disease in the banana (Musa 7 paradisiaca L.) and plantain (Musa acuminata Colla) production around the world. Chemical fungicides are the main control tactics; however, fungicide resistance had increased control costs, besides environmental contamination and consumers demands for a fruit free of pesticide residues. The enhancement of populations of native bacteria through selective substrates, with lytic activity on M. fijiensis, is a management alternative. Application of two foliar substrates, that had a mineral solution plus urea, barley flour and colloidal chitin known to built-up biocontrol bacteria, allowed to decrease fungicide applications from 43 to 46%, when sprayed in rotation with conventional fungicides.La Sigatoka Negra, causada por el hongo Mycosphaerella fijiensis Morelet, es la enfermedad foliar m\ue1s destructora para la producci\uf3n de los cultivos de ba-nano (Musa 7 paradisiaca L.) y pl\ue1tano (Musa acuminata Colla) en el mundo. Actualmente el control de esta enfermedad se centra en la aplicaci\uf3n de fungicidas qu\uedmicos; sin embargo, el pat\uf3geno ha desarrollado resistencia, aumentando los costos de control, el impacto negativo sobre el ambiente y la exigencia de los consumidores por una fruta cada vez m\ue1s libre del uso de plaguicidas. Se ha desarrollado investigaci\uf3n para promover el incremento de poblaciones na-tivas de bacterias con actividad l\uedtica sobre M. fijiensis a trav\ue9s de sustratos foliares selectivos de esta microbiota. La aplicaci\uf3n de sustratos foliares con base en quitina coloidal, harina de cebada como fuente de glucano, urea y una soluci\uf3n mineral base, dise\uf1ados para fomentar poblaciones de bacterias quitinol\uedticas y glucanol\uedticas de ocurrencia natural, mostr\uf3 una reducci\uf3n entre un 43 y 46% en el n\ufamero de ciclos de fungicidas convencionales, al ser aplicados en rotaci\uf3n con estos \ufaltimos, con relaci\uf3n al sistema convencional basado en la aplicaci\uf3n de fungicidas
    • 

    corecore