67 research outputs found

    AA--Dependence of ΛΛ\Lambda\Lambda Bond Energies in Double---Λ\Lambda Hypernuclei

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    The AA-dependence of the bond energy ΔBΛΛ\Delta B_{\Lambda\Lambda} of the ΛΛ{\Lambda\Lambda} hypernuclear ground states is calculated in a three-body Λ+Λ+AZ{\Lambda + \Lambda + {^{A}Z}} model and in the Skyrme-Hartree-Fock approach. Various ΛΛ{\Lambda\Lambda} and Λ\Lambda-nucleus or ΛN{\Lambda N} potentials are used and the sensitivity of ΔBΛΛ\Delta B_{\Lambda\Lambda} to the interactions is discussed. It is shown that in medium and heavy ΛΛ{\Lambda\Lambda} hypernuclei, ΔBΛΛ\Delta B_{\Lambda\Lambda} is a linear function of rΛ3r_{\Lambda}^{-3}, where rΛr_\Lambda is rms radius of the hyperon orbital. It looks unlikely that it will be possible to extract ΛΛ{\Lambda\Lambda} interaction from the double-Λ\Lambda hypernuclear energies only, the additional information about the Λ\Lambda-core interaction, in particular, on rΛr_{\Lambda} is needed.Comment: 11 pages, LaTex, 3 figure

    Faddeev calculations for the A=5,6 Lambda-Lambda hypernuclei

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    Faddev calculations are reported for Lambda-Lambda-5H, Lambda-Lambda-5He and Lambda-Lambda-6He in terms of two Lambda hyperons plus the respective nuclear clusters, using Lambda-Lambda central potentials considered in past non-Faddeev calculations of Lambda-Lambda-6He. The convergence with respect to the partial-wave expansion is studied, and comparison is made with some of these Lambda-Lambda hypernuclear calculations. The Lambda-Lambda Xi-N mixing effect is briefly discussed.Comment: submitted for publicatio

    Risk of chronic arthralgia and impact of pain on daily activities in a cohort of patients with chikungunya virus infection from Brazil

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    Objectives: To investigate risk factors for persistent arthralgia in patients with chikungunya, and describe its impact on daily activities. Methods: From September 2014 to July 2016, a surveillance study enrolled patients with acute febrile illness in Salvador, Brazil, and detected those with chikungunya virus infection using IgM enzyme-linked immunosorbent assay or reverse transcriptase polymerase chain reaction. Telephone follow-ups were performed to ascertain the progression of disease. Results: Of 153 followed cases, 65 (42.5%) reported chronic arthralgia that lasted >3 months, and 47 (30.7%) were still symptomatic at the time of the interview (approximately 1.5 years after symptom onset). Limitations in daily activities and mental distress were reported by 93.8% and 61.5% of those with chronic arthralgia, respectively. Female sex [risk ratio (RR) 1.79, 95% confidence interval (CI) 1.95–2.69] and age (RR 1.02 for each 1-year increase, 95% CI 1.01–1.03) were independent risk factors for chronic arthralgia. Chronic arthralgia was not associated with co-infection with dengue virus (RR 0.97, 95% CI 0.48–1.94) or chikungunya viral load at diagnosis (median chikungunya virus RNA of 5.60 and 5.52 log10 copies/μL for those with and without chronic arthralgia, respectively; P = 0.75). Conclusions: These findings reinforce the high frequency of chronic chikungunya arthralgia, and highlight the substantial disability associated with the persistence of pain. Development of novel strategies to mitigate the transmission of chikungunya virus and to provide long-term medical assistance for patients with chikungunya are needed urgently.Fil: Silva, Monaíse M. O.. Fundación Oswaldo Cruz; BrasilFil: Kikuti, Mariana. Universidade Federal da Bahia; Brasil. Fundación Oswaldo Cruz; BrasilFil: Anjos, Rosângela O.. Fundación Oswaldo Cruz; BrasilFil: Portilho, Moyra M.. Fundación Oswaldo Cruz; BrasilFil: Santos, Viviane C.. Fundación Oswaldo Cruz; BrasilFil: Gonçalves, Thaiza S.F.. Fundación Oswaldo Cruz; BrasilFil: Tauro, Laura Beatriz. Fundación Oswaldo Cruz; Brasil. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú; ArgentinaFil: Moreira, Patrícia S. S.. Fundación Oswaldo Cruz; BrasilFil: Jacob Nascimento, Leile C.. Fundación Oswaldo Cruz; BrasilFil: Santana, Perla M.. Fundación Oswaldo Cruz; BrasilFil: Campos, Gúbio S.. Universidade Federal da Bahia; BrasilFil: Siqueira, André M.. Fundación Oswaldo Cruz; BrasilFil: Kitron, Uriel D.. University of Emory; Estados Unidos. Fundación Oswaldo Cruz; BrasilFil: Reis, Mitermayer G.. University of Yale; Estados Unidos. Fundación Oswaldo Cruz; Brasil. Universidade Federal da Bahia; BrasilFil: Ribeiro, Guilherme S.. Fundación Oswaldo Cruz; Brasil. Universidade Federal da Bahia; Brasi

    Synchronous and proportional deglacial changes in Atlantic meridional overturning and northeast Brazilian precipitation

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    Changes in heat transport associated with fluctuations in the strength of the Atlantic meridional overturning circulation (AMOC) are widely considered to affect the position of the Intertropical Convergence Zone (ITCZ), but the temporal immediacy of this teleconnection has to date not been resolved. Based on a high-resolution marine sediment sequence over the last deglaciation, we provide evidence for a synchronous and near-linear link between changes in the Atlantic interhemispheric sea surface temperature difference and continental precipitation over northeast Brazil. The tight coupling between AMOC strength, sea surface temperature difference, and precipitation changes over northeast Brazil unambiguously points to a rapid and proportional adjustment of the ITCZ location to past changes in the Atlantic meridional heat transport

    Evaluation of HBV-Like circulation in wild and farm animals from Brazil and Uruguay.

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    The origin of the hepatitis B virus is a subject of wide deliberation among researchers. As a result, increasing academic interest has focused on the spread of the virus in different animal species. However, the sources of viral infection for many of these animals are unknown since transmission may occur from animal to animal, human to human, animal to human, and human to animal. The aim of this study was to evaluate hepadnavirus circulation in wild and farm animals (including animals raised under wild or free conditions) from different sites in Brazil and Uruguay using serological and molecular tools. A total of 487 domestic wild and farm animals were screened for hepatitis B virus (HBV) serological markers and tested via quantitative and qualitative polymerase chain reaction (PCR) to detect viral DNA. We report evidence of HBsAg (surface antigen of HBV) and total anti-HBc (HBV core antigen) markers as well as low-copy hepadnavirus DNA among domestic and wild animals. According to our results, which were confirmed by partial genome sequencing, as the proximity between humans and animals increases, the potential for pathogen dispersal also increases. A wider knowledge and understanding of reverse zoonoses should be sought for an effective One Health response

    Transmission of Chikungunya Virus in an Urban Slum, Brazil

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    After a chikungunya outbreak in Salvador, Brazil, we performed a cross-sectional, community-based study of 1,776 inhabitants to determine chikungunya virus (CHIKV) seroprevalence, identify factors associated with exposure, and estimate the symptomatic infection rate. From November 2016 through February 2017, we collected sociodemographic and clinical data by interview and tested serum samples for CHIKV IgG. CHIKV seroprevalence was 11.8% (95% CI 9.8%–13.7%), and 15.3% of seropositive persons reported an episode of fever and arthralgia. Infections were independently and positively associated with residences served by unpaved streets, a presumptive clinical diagnosis of chikungunya, and recall of an episode of fever with arthralgia in 2015–2016. Our findings indicate that the chikungunya outbreak in Salvador may not have conferred sufficient herd immunity to preclude epidemics in the near future. The unusually low frequency of symptomatic disease points to a need for further longitudinal studies to better investigate these findings

    Antitumor activity of photodynamic therapy performed with nanospheres containing zinc-phthalocyanine

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    Abstract\ud \ud Background\ud The increasing incidence of cancer and the search for more effective therapies with minimal collateral effects have prompted studies to find alternative new treatments. Among these, photodynamic therapy (PDT) has been proposed as a very promising new modality in cancer treatment with the lowest rates of side effects, revealing itself to be particularly successful when the photosensitizer is associated with nanoscaled carriers. This study aimed to design and develop a new formulation based on albumin nanospheres containing zinc-phthalocyanine tetrasulfonate (ZnPcS4-AN) for use in the PDT protocol and to investigate its antitumor activity in Swiss albino mice using the Ehrlich solid tumor as an experimental model for breast cancer.\ud \ud \ud Methods\ud Ehrlich tumor’s volume, histopathology and morphometry were used to assess the efficacy of intratumoral injection of ZnPcS4-AN in containing tumor aggressiveness and promoting its regression, while the toxicity of possible treatments was assessed by animal weight, morphological analysis of the liver and kidneys, hemogram, and serum levels of total bilirubin, direct bilirubin, indirect bilirubin, aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma glutamyl transferase (GGT), alkaline phosphatase, creatinine and urea. In order to evaluate the efficacy of PDT, groups of animals treated with intratumoral injection of doxorubicin (Dox) were also investigated.\ud \ud \ud Results\ud Intratumoral injection of ZnPcS4-AN was found to be efficient in mediating PDT to refrain tumor aggressiveness and to induce its regression. Although tumor volume reduction was not significant, PDT induced a remarkable increase in the necrosis area seen in the tumor’s central region, as in other experimental groups, including tumor and Dox treated groups, but also in the tumor’s peripheral region. Further, PDT showed minimal adverse effects. Indeed, the use of ZnPcS4-AN in mediating PDT revealed anti-neoplastic activity similar to that obtained while using intratumoral Dox therapy.\ud \ud \ud Conclusions\ud PDT mediated by the new formulation ZnPcS4-AN enhanced the inhibition of tumor growth while producing practically no adverse effects and thus emerges as a very promising nanotechnology-based strategy for solid cancer treatment.We are grateful to the Sabin Institute/Sabin Laboratories for technical\ud support and to the Brazilian National Council for Technological and Scientific\ud Development (CNPq), the Foundation to Support Research in the Federal\ud District (FAPDF), the Coordination for Further Training of Graduate Staff\ud (CAPES), the Nanobiotechnology-Network CON-NANO (CAPES), INCTNanobiotecnologia\ud (MCTI, CNPq, CAPES), CNANO-UnB, the São Paulo\ud Research Foundation (FAPESP) #08/53719-4 ACT, and the DPP-University of\ud Brasília, for financial support
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