114 research outputs found

    Effective interactions, structure, and pressure in charge-stabilized colloidal suspensions: Critical assessment of charge renormalization methods

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    Charge-stabilized colloidal suspensions display a rich variety of microstructural and thermodynamic properties, which are determined by electro-steric interactions between all ionic species. The large size asymmetry between molecular-scale microions and colloidal macroions allows the microion degrees of freedom to be integrated out, leading to an effective one-component model of microion-dressed colloidal quasi-particles. For highly-charged colloids with strong macroion-microion correlations, nonlinear effects can be incorporated into effective interactions by means of charge renormalization methods. Here, we compare and partially extend several practical mean-field methods of calculating renormalized colloidal interaction parameters, including effective charges and screening constants, as functions of concentration and ionic strength. Within the one-component description, we compute structural and thermodynamic properties from the effective interactions and assess the accuracy of the different methods by comparing predictions with elaborate primitive-model simulations [P. Linse, J. Chem. Phys. 113, 4359 (2000)]. We also compare various prescriptions for the osmotic pressure of suspensions in Donnan equilibrium with a salt ion reservoir, and analyze instances where the macroion effective charge becomes larger than the bare one. The methods assessed include single-center cell, jellium, and multi-center mean-field theories. The strengths and weaknesses of the various methods are critically assessed, with the aim of guiding optimal and accurate implementations.Comment: 27 pages, 15 figure

    The axis IL-10/claudin-10 is implicated in the modulation of aggressiveness of melanoma cells by B-1 lymphocytes

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    B-1 lymphocytes are known to increase the metastatic potential of B16F10 melanoma cells via the extracellular signal-regulated kinase (ERK) pathway. Since IL-10 is associated with B-1 cells performance, we hypothesized that IL-10 could be implicated in the progression of melanoma. In the present work, we found that the C57BL/6 mice, inoculated with B16F10 cells that were co-cultivated with B-1 lymphocytes from IL-10 knockout mice, developed fewer metastatic nodules than the ones which were injected with the melanoma cells that were cultivated in the presence of wild-type B-1 cells. The impairment of metastatic potential of the B16F10 cells was correlated with low activation of the ERK signaling pathway, supporting the idea that the production of IL-10 by B-1 cells influences the behavior of the tumor. A microarray analysis of the B-1 lymphocytes revealed that IL-10 deficiency is associated with down-regulation of the genes that code for claudin-10, a protein that is involved in cell-to-cell contact and that has been linked to lung adenocarcinoma. In order to determine the impact of claudin-10 in the cross-talk between B-1 lymphocytes and the B16F10 tumor cells, we took advantage of small interfering RNA. The silencing of claudin-10 gene in B-1 lymphocytes inhibited activation of the ERK pathway and abrogated the B-1-induced aggressive behavior of the B16F10 cells. Thus, our findings suggest that the axis IL-10/claudin-10 is a promising target for the development of therapeutic agents against aggressive melanoma.Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)Univ Paulista, Environm & Expt Pathol Program, Sao Paulo, SP, BrazilUniv Fed Sao Paulo Escola Paulista Med UNIFESP EPM, Dept Microbiol Immunol & Parasitol, Sao Paulo, SP, BrazilUniv Fed Sao Paulo, Dept Pharmaceut Sci, Campus Diadema, Diadema, SP, BrazilCtr Univ Sao Camilo, Sao Paulo, SP, BrazilUniv Fed Sao Paulo Escola Paulista Med UNIFESP EPM, Nephrol Div, Dept Med, Sao Paulo, SP, BrazilUniv Fed Sao Paulo Escola Paulista Med UNIFESP EPM, Dept Microbiol Immunol & Parasitol, Sao Paulo, SP, BrazilUniv Fed Sao Paulo, Dept Pharmaceut Sci, Campus Diadema, Diadema, SP, BrazilUniv Fed Sao Paulo Escola Paulista Med UNIFESP EPM, Nephrol Div, Dept Med, Sao Paulo, SP, BrazilFAPESP: 11/50256-6FAPESP: 08/50632-5FAPESP: 2016/02189-1CNPq: 472035/2011-8CNPq: 308374/2016-9Web of Scienc

    Occurrence of B chromosomes in Tetragonisca Latreille, 1811 (Hymenoptera, Apidae, Meliponini): A new contribution to the cytotaxonomy of the genus

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    Tetragonisca angustula and Tetragonisca fiebrigi have recently been listed as valid species. This study aimed to cytogenetically investigate both species, emphasizing the new registry of B chromosomes in the tribe Meliponini. We analyzed colonies of T. angustula and T. fiebrigi collected at Tangará da Serra, Mato Grosso, Brazil, through conventional Giemsa staining, C-banding, and base-specific fluorochrome staining (CMA3/DAPI). T. angustula showed 2n = 34 chromosomes in females and n = 17 in males, with karyotype formula 2K = 34AM. T. fiebrigi showed numeric variation, with chromosome number varying from 2n = 34 to 2n = 36 in females and from n = 17 to n = 18 in males, with karyotype formula 2K = 32AM+2AMc and 2K = 32AM+2AMc + 1 or 2 B-chromosomes. The B chromosomes are heterochromatic. In T. fiebrigi, the CMA3/DAPI staining revealed four chromosomes with a CMA3 positive band. All individuals from the same colony showed the same number of B chromosomes. T. angustula and T. fiebrigi showed karyotype divergence, principally due to the presence of B chromosomes, which are found only in T. fiebrigi. Our data corroborate the status of valid species for both T. angustula and T. fiebrigi, as recently proposed

    Violence Against the Elderly: Social Representations of Portuguese and Brazilian Caregivers

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    The increase in life expectancy and elderly people in society, coupled with changes in family structure, have highlighted the importance of formal and informal caregivers of elderly people. Objective: To analyse the social representations of violence against the elderly, of two groups of formal and informal caregivers. Methods: Exploratory, quantitative and qualitative research, supported by the theoretical-methodological reference of the Social Representations Theory and in the context of this, the Central Core Theory. The sample was participated in by 81 formal caregivers from the project “Aging in Safety in the Alentejo - Understanding to Act, of the University of Évora” and 20 informal caregivers from the project “Qualification of caregivers and aspects related to the quality of life of the elderly people dependent on primary and tertiary care: Implementation and protocol evaluation, of the State University of Southwest of Bahia”. We used the Free Word Association Technique. The data was analysed by prototypical analysis based on two matrices by the software IRAMUTEQ (Interface de R pour les Analyses Multidimensionnelles de Textes et de Questionnaires) 0.7 alpha 2. Results: In Portugal, the elements “bad, mistreatment, I will be, sad, anger, patience, physical, injustice, irritation and meanness” stood out in the central core. In Brazil the mention of “hitting” was emphasized. Conclusions: In both Portugal and Brazil, physical violence takes on particular significance in the social representations of caregivers, rather than verbal and psychological violence, which is not present in the central core of social representations of violence against the elderly in either of the countries

    Adjuvant Effect of Killed Propionibacterium acnes on Mouse Peritoneal B-1 Lymphocytes and Their Early Phagocyte Differentiation

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    B-1 lymphocytes are the predominant cells in mouse peritoneal cavity. They express macrophage and lymphocyte markers and are divided into B-1a, B-1b and B-1c subtypes. The role of B-1 cells is not completely clear, but they are responsible for natural IgM production and seem to play a regulatory role. An enriched B-1b cell population can be obtained from non-adherent peritoneal cell cultures, and we have previously demonstrated that these cells undergo differentiation to acquire a mononuclear phagocyte phenotype upon attachment to the substrate in vitro. Nevertheless, the B-1 cell response to antigens or adjuvants has been poorly investigated. Because killed Propionibacterium acnes exhibits immunomodulatory effects on both macrophages and B-2 lymphocytes, we analyzed whether a killed bacterial suspension or its soluble polysaccharide (PS) could modulate the absolute number of peritoneal B-1 cells in BALB/c mice, the activation status of these cells and their ability to differentiate into phagocytes in vitro. In vivo, P. acnes treatment elevated the absolute number of all B-1 subsets, whereas PS only increased B-1c. Moreover, the bacterium increased the number of B-1b cells that were positive for MHC II, TLR2, TLR4, TLR9, IL-4, IL-5 and IL-12, in addition to up-regulating TLR9, CD80 and CD86 expression. PS increased B-1b cell expression of TLR4, TLR9, CD40 and CD86, as well as IL-10 and IL-12 synthesis. Both of the treatments decreased the absolute number of B-1b cells in vitro, suggesting their early differentiation into B-1 cell-derived phagocytes (B-1CDP). We also observed a higher phagocytic activity from the phagocytes that were derived from B-1b cells after P. acnes and PS treatment. The adjuvant effect that P. acnes has on B-1 cells, mainly the B-1b subtype, reinforces the importance of B-1 cells in the innate and adaptive immune responses

    Perfil epidemiológico dos fatores de risco para hipertensão e diabetes em idosos na região centro-oeste entre janeiro de 2003 e abril de 2013 / Epidemiological profile of risk factors for hypertension and diabetes in the elderly in the mid-western region between january 2003 and april 2013

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    O processo de envelhecimento populacional aumenta de forma exponencial e esse curso com os fatores de risco envolvendo a gênese das Doenças Crônicas Não Transmissíveis (DCNT), dentre elas destacam-se a hipertensão arterial sistêmica e diabetes mellitus, sendo esses grandes problemas de saúde pública do país: Foi realizado um estudo epidemiológico transversal e descritivo, com abordagem quantitativa, sobre hipertensão e diabetes em idosos (maiores de 60 anos até 80 +) entre janeiro de 2003 e abril de 2013 na região Centro-Oeste, que está composta pelos seguintes estados: Goiás (GO), Mato Grosso (MT), Mato Grosso do Sul (MS) e o Distrito Federal (DF); por meio do Hipertensão e Diabetes (HIPERDIA) do Sistema Epidemiológicas e Morbidade no Departamento de Informática do Sistema Único de Saúde do Brasil (DATASUS). A amostra colhida, a partir da população idosa, mostrou os coeficientes de prevalência de hipertensão com diabetes, segundo sexo e faixa etária, visto que é imprescindível salientar que entre todos os estados avaliados foi possível perceber que a maior prevalência no sexo feminino (64,32%) em detrimento do masculino (35,68%). Em relação à faixa etária, o perfil predominante foram os intervalos etários de 60 a 64 anos (31, 05%) e 65 a 69 anos (27,08%). Observou-se a seguinte disposição dos fatores de risco na população idosa da Região Centro-Oeste durante janeiro de 2003 a abril 2013: sedentarismo com 31.718 casos, que alcançou o maior número de notificações; sobrepeso com 30.055; tabagismo com 12.497; doença renal com 8.596; outras doenças coronarianas com 7.582; acidente vascular cerebral 7.170; e infarto agudo do miocárdio com 7.105, que obteve o menor número de casos. É imperioso que medidas de profilaxia sejam propostas com maior ênfase juntamente ao desenvolvimento de políticas públicas voltadas a essa temática em conjunto ao aperfeiçoamento das que já existem. As quais podem ser desenvolvidas mediante a implementação de ações voltadas a diligências e orientações de cunho educativo para evidenciar a importância da adesão ao tratamento e da manutenção de práticas que fortaleçam a preservação da qualidade de vida do grupo supramencionado

    J-PLUS: Detecting and studying extragalactic globular clusters. The case of NGC 1023.

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    Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Context. Extragalactic globular clusters (GCs) are key objects in studies of galactic histories. The advent of wide-field surveys, such as the Javalambre Photometric Local Universe Survey (J-PLUS), offers new possibilities for the study of these systems. Aims. We performed the first study of GCs in J-PLUS to recover information on the history of NGC 1023, taking advantage of wide-field images and 12 filters. Methods. We developed the semiautomatic pipeline GCFinder for detecting GC candidates in J-PLUS images, which can also be adapted to similar surveys. We studied the stellar population properties of a sub-sample of GC candidates using spectral energy distribution (SED) fitting. Results. We found 523 GC candidates in NGC 1023, about 300 of which are new. We identified subpopulations of GC candidates, where age and metallicity distributions have multiple peaks. By comparing our results with the simulations, we report a possible broad age-metallicity relation, supporting the notion that NGC 1023 has experienced accretion events in the past. With a dominating age peak at 1010 yr, we report a correlation between masses and ages that suggests that massive GC candidates are more likely to survive the turbulent history of the host galaxy. Modeling the light of NGC 1023, we find two spiral-like arms and detect a displacement of the galaxy’s photometric center with respect to the outer isophotes and center of GC distribution (~700pc and ~1600pc, respectively), which could be the result of ongoing interactions between NGC 1023 and NGC 1023A. Conclusions. By studying the GC system of NGC 1023 with J-PLUS, we showcase the power of multi-band surveys for these kinds of studies and we find evidence to support the complex accretion history of the host galaxy. © D. de Brito Silva et al. 2022.D.B.S. also acknowledges Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) process number 2017J00204-6 for the financial support provided for the development of this project. P.C. acknowledges support from Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) under grant 310041/2018-0 and from Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) process number 2018J05392-8. A.C.S. acknowledges funding from CNPq and the Rio Grande do Sul Research Foundation (FAPERGS) through grants CNPq-403580/2016-1, CNPq-11153/2018-6, PqG/FAPERGS-17/2551-0001, FAPERGS/CAPES 19/2551-0000696-9 and L’Oréal UNESCO ABC Para Mulheres na Ciência and the Chinese Academy of Sciences (CAS) President’s International Fellowship Initiative (PIFI) through grant E085201009. G.B. acknowledges financial support from the National Autonomous University of México (UNAM) through grant DGAPA/PAPIIT IG100319 and from CONACyT through grant CB2015-252364. J.V. acknowledges the technical members of the UPAD for their invaluable work: Juan Castillo, Tamara Civera, Javier Hernández, Ángel López, Alberto Moreno, and David Muniesa. J.A.H.J. acknowledges Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP), process number 2021J08920-8. A.E. acknowledges the financial support from the Spanish Ministry of Science and Innovation and the European Union – NextGenerationEU through the Recovery and Resilience Facility project ICTS-MRR-2021-03-CEFCA and from Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) under grant 313285/2020-9 D.A.F. thanks the ARC for financial assistance via DP170102344. Y.J.-T has received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement No 898633. Y.J-T. also acknowledges financial support from the State Agency for Research of the Spanish MCIU through the “Center of Excellence Severo Ochoa” award to the Instituto de Astrofísica de Andalucía (SEV-2017-0709). Based on observations made with the JAST80 telescope telescope/s at the Observatorio Astrofísico de Javalambre, in Teruel, owned, managed, and operated by the Centro de Estudios de Física del Cosmos de Aragón. We thank the Centro de Estudios de Física del Cosmos de Aragón for the allocation of the Director’s Discretionary Time to this program. We thank the OAJ Data Processing and Archiving Unit (UPAD) for reducing and calibrating the OAJ data used in this work. Funding for the J-PLUS Project has been provided by the Governments of Spain and Aragón through the Fondo de Inversiones de Teruel; the Aragón Government through the Research Groups E96, E103, and E16_17R; the Spanish Ministry of Science, Innovation, and Universities (MCIU/AEI/FEDER, UE) with grants PGC2018-097585-B-C21 and PGC2018-097585-B-C22; the Spanish Ministry of Economy and Competitiveness (MINECO) under AYA2015-66211-C2-1-P, AYA2015-66211-C2-2, AYA2012-30789, and ICTS-2009-14; and European FEDER funding (FCDD10-4E-867, FCDD13-4E-2685). The Brazilian agencies FINEP, FAPESP, and the National Observatory of Brazil have also contributed to this project. This work has made use of the computing facilities of the Laboratory of Astroinformatics (IAG/USP, NAT/Unicsul), whose purchase was made possible by the Brazilian agency FAPESP (grant 2009/54006-4) and the INCT-A.Peer reviewe
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