189 research outputs found

    Disentangling superconducting and magnetic orders in NaFe_1-xNi_xAs using muon spin rotation

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    Muon spin rotation and relaxation studies have been performed on a "111" family of iron-based superconductors NaFe_1-xNi_xAs. Static magnetic order was characterized by obtaining the temperature and doping dependences of the local ordered magnetic moment size and the volume fraction of the magnetically ordered regions. For x = 0 and 0.4 %, a transition to a nearly-homogeneous long range magnetically ordered state is observed, while for higher x than 0.4 % magnetic order becomes more disordered and is completely suppressed for x = 1.5 %. The magnetic volume fraction continuously decreases with increasing x. The combination of magnetic and superconducting volumes implies that a spatially-overlapping coexistence of magnetism and superconductivity spans a large region of the T-x phase diagram for NaFe_1-xNi_xAs . A strong reduction of both the ordered moment size and the volume fraction is observed below the superconducting T_C for x = 0.6, 1.0, and 1.3 %, in contrast to other iron pnictides in which one of these two parameters exhibits a reduction below TC, but not both. The suppression of magnetic order is further enhanced with increased Ni doping, leading to a reentrant non-magnetic state below T_C for x = 1.3 %. The reentrant behavior indicates an interplay between antiferromagnetism and superconductivity involving competition for the same electrons. These observations are consistent with the sign-changing s-wave superconducting state, which is expected to appear on the verge of microscopic coexistence and phase separation with magnetism. We also present a universal linear relationship between the local ordered moment size and the antiferromagnetic ordering temperature TN across a variety of iron-based superconductors. We argue that this linear relationship is consistent with an itinerant-electron approach, in which Fermi surface nesting drives antiferromagnetic ordering.Comment: 20 pages, 14 figures, Correspondence should be addressed to Prof. Yasutomo Uemura: [email protected]

    Immunogenicity of influenza H1N1 vaccination in mixed connective tissue disease: effect of disease and therapy

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    OBJECTIVE: To assess the potential acute effects regarding the immunogenicity and safety of non-adjuvanted influenza A H1N1/2009 vaccine in patients with mixed connective tissue disease and healthy controls. METHODS: Sixty-nine mixed connective tissue disease patients that were confirmed by Kasukawa's classification criteria and 69 age- and gender-matched controls participated in the study; the participants were vaccinated with the non-adjuvanted influenza A/California/7/2009 (H1N1) virus-like strain. The percentages of seroprotec-tion, seroconversion, geometric mean titer and factor increase in the geometric mean titer were calculated. The patients were clinically evaluated, and blood samples were collected pre- and 21 days post-vaccination to evaluate C-reactive protein, muscle enzymes and autoantibodies. Anti-H1N1 titers were determined using an influenza hemagglutination inhibition assay. ClinicalTrials.gov: NCT01151644. RESULTS: Before vaccination, no difference was observed regarding the seroprotection rates (p = 1.0) and geometric mean titer (p = 0.83) between the patients and controls. After vaccination, seroprotection (75.4% vs. 71%, (p = 0.7), seroconversion (68.1% vs. 65.2%, (p = 1.00) and factor increase in the geometric mean titer (10.0 vs. 8.0, p = 0.40) were similar in the two groups. Further evaluation of seroconversion in patients with and without current or previous history of muscle disease (p = 0.20), skin ulcers (p = 0.48), lupus-like cutaneous disease (p = 0.74), secondary Sjogren syndrome (p = 0.78), scleroderma-pattern in the nailfold capillaroscopy (p = 1.0), lymphopenia #1000/mm³ on two or more occasions (p = 1.0), hypergammaglobulinemia $1.6 g/d (p = 0.60), pulmonary hypertension (p = 1.0) and pulmonary fibrosis (p = 0.80) revealed comparable rates. Seroconversion rates were also similar in patients with and without immunosuppressants. Disease parameters, such as C-reactive protein (p = 0.94), aldolase (p = 0.73), creatine phosphokinase (p = 0.40) and ribonucleoprotein antibody levels (p = 0.98), remained largely unchanged pre and post-vaccination. No severe side effects were reported. CONCLUSIONS: The non-adjuvanted influenza A/H1N1 vaccination immune response in mixed connective tissue disease patients is adequate and does not depend on the disease manifestations and therapy

    Ordered mesoporous silica materials for protein adsorption

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    Lysozyme and BSA were used, as model proteins of considerably different dimensions, in order to evaluate the influence of the distinct pore structural characteristics of three types of ordered mesoporous silica materials (MCF, SBA-15 and MCM-41) on protein adsorption. Characterisation by X ray diffraction and nitrogen adsorption at 77K revealed the typical pore structural features of each type of material. The maximum of the pore size distributions indicated that the width of the windows of MCF (2) (mesitylene/P123 of 2) was larger than the pore diameter of the unidirectional tubular pores of SBA-15. All the materials presented similar small external surface areas but high pore volumes, with that of MCF (2) being the highest. The adsorption of lysozyme at pH=8 increased in the order MCM-41<< SBA-15< MCF (2), and the uptakes were well above those of BSA at pH=5. Although BSA is not completely excluded from the mesopores of SBA-15 and MCF (2), as happens with MCM-41, the adsorption occurs to a very limited extent. The overall behaviour of these SBA-15 and MCF (2) samples was not significantly different and both revealed potential for the separation of these proteins

    Juvenile onset systemic lupus erythematosus: a possible role for vitamin D in disease status and bone health

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    Purpose: In juvenile onset systemic lupus erythematosus (JoSLE), evidence for the association between vitamin D status, lupus activity, and bone health is very limited and not conclusive. The aim of this study was, therefore, to assess in JoSLE patients the possible relevance of vitamin D deficiency in disease and bone parameters. Methods: Fifty-seven JoSLE patients were initially compared to 37 age, race and body mass index (BMI) -matched healthy controls. The serum concentration of 25 hydroxyvitamin D (25OHD) was determined by radioimmunoassay. Patients with 25OHD deficiency (acurrency sign20 ng/mL) were compared to those with levels &gt; 20 ng/mL. Disease activity was evaluated by SLE Disease Activity Index (SLEDAI). Bone mineral density (BMD) and body composition (BC) were measured using dual-energy X-ray absorptiometry (DXA). Results: 25OHD levels were similar in patients and controls (21.44 +/- 7.91 vs 22.54 +/- 8.25 ng/mL, p = 0.519), regardless of supplementation (65% of patients and none in controls). Thirty-one patients with 25OHD deficiency (acurrency sign20 ng/mL) were further compared to the 26 JoSLE patients with levels &gt; 20 ng/mL. These two groups were well-balanced regarding vitamin D confounding variables: age (p = 0.100), ethnicity (p = 1.000), BMI (p = 0.911), season (p = 0.502), frequency of vitamin D supplementation (p = 0.587), creatinine (p = 0.751), renal involvement (p = 0.597), fat mass (p = 0.764), lean mass (p = 0.549), previous/current use of glucocorticoids(GC) (p = 1.0), immunosuppressors (p = 0.765), and mean current daily dose of GC (p = 0.345). Patients with vitamin D deficiency had higher SLEDAI (3.35 +/- 4.35 vs 1.00 +/- 2.48, p = 0.018), lower C4 levels (12.79 +/- 6.78 vs 18.38 +/- 12.24 mg/dL, p = 0.038), lower spine BMD (0.798 +/- 0.148 vs 0.880 +/- 0.127 g/cm2, p = 0.037) and whole body BMD (0.962 +/- 0.109 vs 1.027 +/- 0.098 g/cm2, p = 0.024). Conclusion: JoSLE vitamin D deficiency, in spite of conventional vitamin D supplementation, affects bone and disease activity status independent of therapy and fat mass reinforcing the recommendation to achieve adequate levels. Lupus (2012) 21, 1335-1342.Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) [2010/08312-3]Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)Conselho Nacional de Desenvolvimento Cientifico e Tecnologico [301411/2009-3, 300559/2009-7]Conselho Nacional de Desenvolvimento Cientifico e TecnologicoFederico FoundationFederico Foundatio

    Isogeometric analysis for fluid shear stress in cancer cells

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    Este trabalho foi financiado pelo Concurso Anual para Projetos de Investigação, Desenvolvimento, Inovação e Criação Artística (IDI&CA) 2018 do Instituto Politécnico de Lisboa. Código de referência IPL/2018/IGACFC_ISELThe microenvironment of the tumor is a key factor regulating tumor cell invasion and metastasis. The effects of physical factors in tumorigenesis is unclear. Shear stress, induced by liquid flow, plays a key role in proliferation, apoptosis, invasion, and metastasis of tumor cells. The mathematical models have the potential to elucidate the metastatic behavior of the cells’ membrane exposed to these microenvironment forces. Due to the shape configuration of the cancer cells, Non-uniform Rational B-splines (NURBS) lines are very adequate to define its geometric model. The Isogeometric Analysis allows a simplified transition of exact CAD models into the analysis avoiding the geometrical discontinuities of the traditional Galerkin traditional techniques. In this work, we use an isogeometric analysis to model the fluid-generated forces that tumor cells are exposed to in the vascular and tumor microenvironments, in the metastatic process. Using information provided by experimental tests in vitro, we present a suite of numerical experiments which indicate, for standard configurations, the metastatic behavior of cells exposed to such forces. The focus of this paper is strictly on geometrical sensitivities to the shear stress’ exhibition for the cell membrane, this being its innovation.info:eu-repo/semantics/publishedVersio

    Anti-SARS-CoV-2 inactivated vaccine in patients with ANCA-associated vasculitis: Immunogenicity, safety, antibody decay and the booster dose

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    Objective: To evaluate inactivated CoronaVac prime vaccination, antibody decay, booster dose, and safety in ANCA-Associated Vasculitis (AAV) patients. Methods: Fifty-three AAV patients and 106 Controls (CG) received CoronaVac on days: D0 (first dose), D28(second dose), and D210 (booster dose, 32 AAV: 32 CG). The primary outcome was immunogenicity after the second vaccine dose (day 69) assessed by Seroconversion Rates (SC) of anti-SARS-CoV-2 S1/S2 IgG and Neutralizing Antibodies (NAb). Secondary outcomes were safety, immunogenicity (D28/D240), 6-months antibody decay (D210) and the booster dose response (D240). Results: At D69 SC (65.1% vs. 96.8%, p&nbsp;=&nbsp;0.0001), GMT (21.3&nbsp;UA/mL vs. 67.7&nbsp;UA/mL, p&nbsp;&lt;&nbsp;0.001) and NAb- positivity (53.7% vs. 80.6%, p&nbsp;=&nbsp;0.001) were moderate but lower in naïve-AAV patients than CG. Patients without SC used more often IS (93.3% vs. 53.3%, p&nbsp;=&nbsp;0.015), mycophenolate mofetil (20% vs. 0%, p&nbsp;=&nbsp;0.037) and prednisone (60.0% vs. 28.6%, p&nbsp;=&nbsp;0.057) than seroconverted. NAb negativity in AAV patients was associated with prednisone treatment (57.9% vs. 18.2%, p&nbsp;=&nbsp;0.015) and IS (84.2% vs. 55.0%, p&nbsp;=&nbsp;0.046). Logistic regression analysis models showed that only prednisone was associated with lower seroconversion (OR&nbsp;=&nbsp;0.2, 0,95% CI 0.05‒0.86, p&nbsp;=&nbsp;0.030) and with lower NAb positivity (OR&nbsp;=&nbsp;0.2, 0,95% CI 0.05‒0.88, p&nbsp;=&nbsp;0.034). After six months (D69‒D210) a decrease in IgG positivity occurred in 32 AAV patients (15.7%, p&nbsp;=&nbsp;0.074) and 32 CG (18.7%, p&nbsp;=&nbsp;0.041). For the NAb positivity, the 6-month decrease was not significant (p&nbsp;=&nbsp;0.114) whereas a major reduction occurred for CG (p&nbsp;&lt;&nbsp;0.001). A booster dose (D240) resulted in an increment in IgG-positivity (21.9%, p&nbsp;=&nbsp;0.023) and NAb-positivity (34.4%, p&nbsp;=&nbsp;0.006) in AAV patients. No moderate/severe adverse events attributable to the vaccine were observed. Conclusion: This study provides novel data on the excellent safety and moderate immunogenicity of CoronaVac in AAV patients. A six-month mild antibody waning was observed with a good response to the booster dose, although levels remained lower than CG (CoronavRheum-NCT04754698)

    Physical activity: a strategy to improve antibody response to a SARS-CoV-2 vaccine booster dose in patients with autoimmune rheumatic diseases.

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    Physical activity associates with improved immunogenicity following a 2-dose schedule of CoronaVac (Sinovac's inactivated SARS-CoV-2 vaccine) in patients with autoimmune rheumatic diseases (ARD). This study evaluates whether physical activity impacts vaccine-induced antibody responses to a booster dose in this population. This was a phase-4 trial conducted in Sao Paulo, Brazil. Patients with ARD underwent a 3-dose schedule of CoronaVac. One month after the booster, we assessed seroconversion rates of anti-SARS-CoV-2 S1/S2 IgG, geometric mean titers of anti-S1/S2 IgG, frequency of positive neutralizing antibodies, and neutralizing activity. Physical activity was assessed through questionnaire. Physically active (n = 362) and inactive (n = 278) patients were comparable for most characteristics; however, physically active patients were younger (P<.01) and had a lower frequency of chronic inflammatory arthritis (P<.01). Adjusted models showed that physically active patients had -2 times odds of seroconversion rates (OR: 2.09; 95% confidence interval, 1.22 to 3.61), -22% greater geometric mean titers of anti-S1/S2 IgG (22.09%; 95% confidence interval, 3.91 to 65.60), and -7% greater neutralizing activity (6.76%; 95% confidence interval, 2.80 to 10.72) than inactive patients. Patients with ARD who are physically active have greater odds of experiencing better immunogenicity to a booster dose of CoronaVac. These results support the recommendation of physical activity to improve vaccination responses, particularly for immunocompromised individuals

    No associations between physical activity and immunogenicity in SARS-CoV-2 seropositive patients with autoimmune rheumatic diseases prior to and after vaccination.

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    To investigate the association between physical activity and immunogenicity among SARS-CoV-2 seropositive patients with autoimmune rheumatic diseases prior to and following a 2-dose schedule of CoronaVac (Sinovac inactivated vaccine). This was a prospective cohort study within an open-label, single-arm, phase 4 vaccination trial conducted in Sao Paulo, Brazil. In this substudy, only SARS-CoV-2 seropositive patients were included. Immunogenicity was assessed by seroconversion rates of total anti-SARS-CoV-2 S1/S2 immunoglobulin G (IgG), geometric mean titers of anti-S1/S2 IgG, frequency of positive neutralizing antibodies, and neutralizing activity before and after vaccination. Physical activity was assessed through a questionnaire. Model-based analyses were performed controlling for age (30 kg/m2), and use of prednisone, immunosuppressants, and biologics. A total of 180 seropositive autoimmune rheumatic disease patients were included. There was no association between physical activity and immunogenicity before and after vaccination. This study suggests that the positive association between physical activity and greater antibody responses seen in immunocompromised individuals following vaccination is overridden by previous SARS-CoV-2 infection, and does not extend to natural immunity

    A framework for remission in SLE: consensus findings from a large international task force on definitions of remission in SLE (DORIS)

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    Objectives Treat-to-target recommendations have identified 'remission' as a target in systemic lupus erythematosus (SLE), but recognise that there is no universally accepted definition for this. Therefore, we initiated a process to achieve consensus on potential definitions for remission in SLE. Methods An international task force of 60 specialists and patient representatives participated in preparatory exercises, a face-to-face meeting and follow-up electronic voting. The level for agreement was set at 90%. Results The task force agreed on eight key statements regarding remission in SLE and three principles to guide the further development of remission definitions: 1. Definitions of remission will be worded as follows: remission in SLE is a durable state characterised by . (reference to symptoms, signs, routine labs). 2. For defining remission, a validated index must be used, for example, clinical systemic lupus erythematosus disease activity index (SLEDAI)=0, British Isles lupus assessment group (BILAG) 2004 D/E only, clinical European consensus lupus outcome measure (ECLAM)=0; with routine laboratory assessments included, and supplemented with physician's global assessment. 3. Distinction is made between remission off and on therapy: remission off therapy requires the patient to be on no other treatment for SLE than maintenance antimalarials; and remission on therapy allows patients to be on stable maintenance antimalarials, low-dose corticosteroids (prednisone ≤5 mg/day), maintenance immunosuppressives and/or maintenance biologics. The task force also agreed that the most appropriate outcomes (dependent variables) for testing the prognostic value (construct validity) of potential remission definitions are: death, damage, flares and measures of health-related quality of life. Conclusions The work of this international task force provides a framework for testing different definitions of remission against long-term outcomes
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