425 research outputs found

    Potential ring of Dirac nodes in a new polymorph of Ca3_3P2_2

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    We report the crystal structure of a new polymorph of Ca3_3P2_2, and an analysis of its electronic structure. The crystal structure was determined through Rietveld refinements of powder synchrotron x-ray diffraction data. Ca3_3P2_2 is found to be a variant of the Mn5_5Si3_3 structure type, with a Ca ion deficiency compared to the ideal 5:3 stoichiometry to yield a charge-balanced compound. We also report the observation of a secondary phase, Ca5_5P3_3H, in which the Ca and P sites are fully occupied and the presence of interstitial hydride ions creates a closed-shell electron-precise compound. We show via electronic structure calculations of Ca3_3P2_2 that the compound is stabilized by a gap in the density of states compared to the hypothetical compound Ca5_5P3_3. Moreover, the calculated band structure of Ca3_3P2_2 indicates that it should be a three-dimensional Dirac semimetal with a highly unusual ring of Dirac nodes at the Fermi level. The Dirac states are protected against gap opening by a mirror plane in a manner analogous to graphene. The results suggest that further study of the electronic properties of Ca3_3P2_2 will be of interest

    Peptide inhibition of human cytomegalovirus infection

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    <p>Abstract</p> <p>Background</p> <p>Human cytomegalovirus (HCMV) is the most prevalent congenital viral infection in the United States and Europe causing significant morbidity and mortality to both mother and child. HCMV is also an opportunistic pathogen in immunocompromised individuals, including human immunodeficiency virus (HIV)- infected patients with AIDS, and solid organ and allogeneic stem cell transplantation recipients. Current treatments for HCMV-associated diseases are insufficient due to the emergence of drug-induced resistance and cytotoxicity, necessitating novel approaches to limit HCMV infection. The aim of this study was to develop therapeutic peptides targeting glycoprotein B (gB), a major glycoprotein of HCMV that is highly conserved across the <it>Herpesviridae </it>family, that specifically inhibit fusion of the viral envelope with the host cell membrane preventing HCMV entry and infection.</p> <p>Results</p> <p>Using the Wimley-White Interfacial Hydrophobicity Scale (WWIHS), several regions within gB were identified that display a high potential to interact with lipid bilayers of cell membranes and hydrophobic surfaces within proteins. The ability of synthetic peptides analogous to WWIHS-positive sequences of HCMV gB to inhibit viral infectivity was evaluated. Human foreskin fibroblasts (HFF) were infected with the Towne-GFP strain of HCMV (0.5 MOI), preincubated with peptides at a range of concentrations (78 nm to 100 μM), and GFP-positive cells were visualized 48 hours post-infection by fluorescence microscopy and analyzed quantitatively by flow cytometry. Peptides that inhibited HCMV infection demonstrated different inhibitory concentration curves indicating that each peptide possesses distinct biophysical properties. Peptide 174-200 showed 80% inhibition of viral infection at a concentration of 100 μM, and 51% and 62% inhibition at concentrations of 5 μM and 2.5 μM, respectively. Peptide 233-263 inhibited infection by 97% and 92% at concentrations of 100 μM and 50 μM, respectively, and 60% at a concentration of 2.5 μM. While peptides 264-291 and 297-315, individually failed to inhibit viral infection, when combined, they showed 67% inhibition of HCMV infection at a concentration of 0.125 μM each.</p> <p>Conclusions</p> <p>Peptides designed to target putative fusogenic domains of gB provide a basis for the development of novel therapeutics that prevent HCMV infection.</p

    Etiopathogenesis of Burkitt's lymphoma: a lesson from a BL-like in CD1 mouse immune to Plasmodium yoelii yoelii

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    <p>Abstract</p> <p>Introduction</p> <p>There is a jaw cancer that develops in children five to eight years old in holoendemic malaria regions of Africa, associated to malaria and Epstein Barr virus infections (EBV). This malignancy is known as endemic Burkitt's lymphoma, and histopatologically is characterized by a starry sky appearance. To date, no histopathologic expression of Burkitt's lymphoma has been reported in non-genetically manipulated experimental animals. The purpose of the study is to describe the case of a mouse immune to <it>Plasmodium yoelii yoelii </it>(Pyy) that developed a Burkitt's lymphoma-like neoplasm after repeated malaria infections.</p> <p>Results</p> <p>Immune mouse 10 (IM-10) developed neoplasms at eight months of age, after receiving three Pyy inoculations. At autopsy eight subcutaneous tumors were found of which the right iliac fosse tumor perforated the abdominal wall and invaded the colon. The histopathologic study showed that all neoplasms were malignant lymphomas of large non-cleaved cells also compatible with variants or previous states of development of a Burkitt's lymphoma-like. The thymus, however, showed a typical starry sky Burkitt's lymphoma-like neoplasm.</p> <p>Conclusions</p> <p>Neoplasm development in CD1 mouse is associated to both, immunity against malaria and continuous antigenic stimulation with living parasites.</p> <p>It is the first observation of a histopathologically expressed Human Burkitt's lymphoma-like neoplasm in a non-genetically manipulated mouse.</p> <p>Chronic immune response associated to neoplasms development could probably be not an exclusive expression of malaria-host interaction but, it could be a pattern that can bee applied also to other agent-host interactions such as host-bacteria, fungus, virus and other parasites.</p

    MEDIATION AS ALTERNATIVE DISPUTE RESOLUTION: LEGAL ANALYSIS, FOREIGN PRACTICE, AND PERSPECTIVES IN RUSSIA

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    Purposes: The article is devoted to the analysis of legal problems of mediation as an alternative way to resolve disputes. The article examines the Russian and foreign experience in the legal regulation of mediation. Methodology: The use and adaptation of foreign experience in applying the mediation procedure are aimed at increasing the speed of dispute resolution, the level of confidentiality and the ability to maintain partnerships. The authors suggest ways to improve the effectiveness and applicability of this procedure in practice. According to Sungatullina L.A., it seems efficient and promising to use alternative methods for resolving disputes in general and to apply the mediation procedure in particular. Izmailov R.R. He believes that the experience of using mediation techniques has shown its effectiveness in resolving various categories of disputes: labor, family, corporate, business conflicts, as well as in the field of housing relations. Mikhailov A.V. notes that the effectiveness of the mediation process largely depends on the implementation at all stages of the basic principles. Results: The authors conclude that it is advisable to apply mediation to disputes arising from administrative and other public relations. As one of the ways to improve the legislative regulation of mediation, it is proposed to consider the possibility of introducing a notarial certification of mediation agreements. Implications/Applications: Alternative dispute resolution is a set of procedures that facilitate non-judicial dispute resolution. In English practice, it is indicated by the steady turnover of Alternative dispute resolution (hereinafter - ADR). Different non-judicial forms of resolution of a case are referred to ADR in different countries. As a rule, three well-known forms are called: arbitration, mediation, and negotiations. Novelty/Originality: The novelty of this study in classifying the mediation techniques

    Arbovirus emergence in the temperate city of Córdoba, Argentina, 2009-2018

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    The distribution of arbovirus disease transmission is expanding from the tropics and subtropics into temperate regions worldwide. The temperate city of Córdoba, Argentina has been experiencing the emergence of dengue virus, transmitted by the mosquito Aedes aegypti, since 2009, when autochthonous transmission of the virus was first recorded in the city. The aim of this work is to characterize the emergence of dengue and related arboviruses (Zika and chikungunya) in Córdoba since 2009. Herein, we present a data set with all known information about transmission of dengue, Zika, and chikungunya viruses in Córdoba, Argentina from 2009-2018, including what information is known of dengue virus (DENV) serotypes in circulation and origins of imported cases. The data presented in this work will assist researchers in investigating drivers of arbovirus emergence and transmission in Córdoba, Argentina and contribute to a better understanding of the global problem of the expanding distribution of arbovirus disease transmission.Fil: Robert, Michael A.. University Of The Sciences; Estados UnidosFil: Tinunin, Daniela T.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Biológicas y Tecnológicas. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto de Investigaciones Biológicas y Tecnológicas; ArgentinaFil: Benitez, Elisabet Marina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Biológicas y Tecnológicas. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto de Investigaciones Biológicas y Tecnológicas; ArgentinaFil: Ludueña Almeida, Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Biológicas y Tecnológicas. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto de Investigaciones Biológicas y Tecnológicas; ArgentinaFil: Romero, Moory. State University of New York; Estados UnidosFil: Stewart-Ibarra, Anna M.. State University of New York; Estados UnidosFil: Estallo, Elizabet Lilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Biológicas y Tecnológicas. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto de Investigaciones Biológicas y Tecnológicas; Argentin

    Electromagnetic scattering of two-dimensional electronic systems

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    Pearson syndrome, a rare mitochondriopathy - case report / Síndrome de Pearson, uma mitocondriopatia rara - relato de caso

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    Pearson's Syndrome (PS) is a rare multisystemic mitochondriopathy caused by deletions and/or duplications in mitochondrial DNA (mtDNA). We describe a girl, age 3 years and 10 months, who was diagnosed with PS.  The case highlights two main characteristics of PS: dysfunction in the hematopoietic system, and pancreatic exocrine insufficiency. The PS diagnosis in the present case was confirmed via molecular diagnosis, specifically mtDNA analysis, which revealed the presence of heterozygosis deletions in the MT-ND4, MT-ND5, MT-ND6 and MT-TM genes. The patient is dependent on erythropoietin to maintain hemoglobin levels, and pancreatin to manage pancreatic dysfunction. She has surpassed the average longevity of Pearson's Syndrome patients, who usually die before age three. The PS case described here also highlights the importance of molecular diagnosis in patients exhibiting multisystemic symptoms of unknown etiology.

    Fecal contamination of drinking water within peri-urban households, Lima, Peru.

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    We assessed fecal contamination of drinking water in households in 2 peri-urban communities of Lima, Peru. We measured Escherichia coli counts in municipal source water and, within households, water from principal storage containers, stored boiled drinking water, and water in a serving cup. Source water was microbiologically clean, but 26 (28%) of 93 samples of water stored for cooking had fecal contamination. Twenty-seven (30%) of 91 stored boiled drinking water samples grew E. coli. Boiled water was more frequently contaminated when served in a drinking cup than when stored (P < 0.01). Post-source contamination increased successively through the steps of usage from source water to the point of consumption. Boiling failed to ensure safe drinking water at the point of consumption because of easily contaminated containers and poor domestic hygiene. Hygiene education, better point-of-use treatment and storage options, and in-house water connections are urgently needed

    Beyond birth-weight: early growth and adolescent blood pressure in a Peruvian population

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    Background. Longitudinal investigations into the origins of adult essential hypertension have found elevated blood pressure in children to accurately track into adulthood, however the direct causes of essential hypertension in adolescence and adulthood remains unclear.Methods. We revisited 152 Peruvian adolescents from a birth cohort tracked from 0 to 30 months of age, and evaluated growth via monthly anthropometric measurements between 1995 and 1998, and obtained anthropometric and blood pressure measurements 11–14 years later. We used multivariable regression models to study the effects of infantile and childhood growth trends on blood pressure and central obesity in early adolescence.Results. In regression models adjusted for interim changes in weight and height, each 0.1 SD increase in weight for length from 0 to 5 months of age, and 1 SD increase from 6 to 30 months of age, was associated with decreased adolescent systolic blood pressure by 1.3 mm Hg (95% CI −2.4 to −0.1) and 2.5 mm Hg (95% CI −4.9 to 0.0), and decreased waist circumference by 0.6 (95% CI −1.1 to 0.0) and 1.2 cm (95% CI −2.3 to −0.1), respectively. Growth in infancy and early childhood was not significantly associated with adolescent waist-to-hip ratio.Conclusions. Rapid compensatory growth in early life has been posited to increase the risk of long-term cardiovascular morbidities such that nutritional interventions may do more harm than good. However, we found increased weight growth during infancy and early childhood to be associated with decreased systolic blood pressure and central adiposity in adolescence

    Epidemiologic Differences Between Cyclosporiasis and Cryptosporidiosis in Peruvian Children

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    We compared the epidemiologic characteristics of cyclosporiasis and cryptosporidiosis in data from a cohort study of diarrhea in a periurban community near Lima, Peru. Children had an average of 0.20 episodes of cyclosporiasis/year and 0.22 episodes of cryptosporidiosis/year of follow-up. The incidence of cryptosporidiosis peaked at 0.42 for 1-year-old children and declined to 0.06 episodes/child-year for 5- to 9-year-old children. In contrast, the incidence of cyclosporiasis was fairly constant among 1- to 9-year-old children (0.21 to 0.28 episodes/child-year). Likelihood of diarrhea decreased significantly with each episode of cyclosporiasis; for cryptosporidiosis, this trend was not statistically significant. Both infections were more frequent during the warm season (December to May) than the cooler season (June to November). Cryptosporidiosis was more frequent in children from houses without a latrine or toilet. Cyclosporiasis was associated with ownership of domestic animals, especially birds, guinea pigs, and rabbits
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