653 research outputs found

    On the 2D Dirac oscillator in the presence of vector and scalar potentials in the cosmic string spacetime in the context of spin and pseudospin symmetries

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    The Dirac equation with both scalar and vector couplings describing the dynamics of a two-dimensional Dirac oscillator in the cosmic string spacetime is considered. We derive the Dirac-Pauli equation and solve it in the limit of the spin and the pseudo-spin symmetries. We analyze the presence of cylindrical symmetric scalar potentials which allows us to provide analytic solutions for the resultant field equation. By using an appropriate ansatz, we find that the radial equation is a biconfluent Heun-like differential equation. The solution of this equation provides us with more than one expression for the energy eigenvalues of the oscillator. We investigate these energies and find that there is a quantum condition between them. We study this condition in detail and find that it requires the fixation of one of the physical parameters involved in the problem. Expressions for the energy of the oscillator are obtained for some values of the quantum number nn. Some particular cases which lead to known physical systems are also addressed.Comment: 15 pages, 8 figures, matches published versio

    Local roughness exponent in the nonlinear molecular-beam-epitaxy universality class in one-dimension

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    We report local roughness exponents, αloc\alpha_{\text{loc}}, for three interface growth models in one dimension which are believed to belong the non-linear molecular-beam-epitaxy (nMBE) universality class represented by the Villain-Lais-Das Sarma (VLDS) stochastic equation. We applied an optimum detrended fluctuation analysis (ODFA) [Luis et al., Phys. Rev. E 95, 042801 (2017)] and compared the outcomes with standard detrending methods. We observe in all investigated models that ODFA outperforms the standard methods providing exponents in the narrow interval αloc[0.96,0.98]\alpha_{\text{loc}}\in[0.96,0.98] consistent with renormalization group predictions for the VLDS equation. In particular, these exponent values are calculated for the Clarke-Vvdensky and Das Sarma-Tamborenea models characterized by very strong corrections to the scaling, for which large deviations of these values had been reported. Our results strongly support the absence of anomalous scaling in the nMBE universality class and the existence of corrections in the form αloc=1ϵ\alpha_{\text{loc}}=1-\epsilon of the one-loop renormalization group analysis of the VLDS equation

    Synbiotic therapy decreases microbial translocation and inflammation and improves immunological status in HIV-infected patients: a double-blind randomized controlled pilot trial

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    BACKGROUND: HIV-infection results in damage and dysfunction of the gastrointestinal system. HIV enteropathy includes pronounced CD4+ T-cell loss, increased intestinal permeability, and microbial translocation that promotes systemic immune activation, which is implicated in disease progression. A synbiotic is the combination of probiotics and prebiotics that could improve gut barrier function. Our study goal was to determine whether the use of a synbiotic, probiotics or a prebiotic can recover immunological parameters in HIV-infected subjects through of a reduction of microbial translocation and pro-inflammatory cytokine production. METHODS: A randomized, double-blind controlled study was performed; twenty Antiretroviral treatment-naïve HIV-infected subjects were subgrouped and assigned to receive a synbiotic, probiotics, a prebiotic, or a placebo throughout 16 weeks. RESULTS: We had no reports of serious adverse-events. From baseline to week 16, the synbiotic group showed a reduction in bacterial DNA concentrations in plasma (p = 0.048). Moreover, the probiotic and synbiotic groups demonstrated a decrease in total bacterial load in feces (p = 0.05). The probiotic group exhibited a significant increment of beneficial bacteria load (such as Bifidobacterium; p = 0.05) and a decrease in harmful bacteria load (such as Clostridium; p = 0.063). In the synbiotic group, the CD4+ T-cells count increased (median: +102 cells/μL; p = 0.05) and the level of Interleukin 6 cytokine decreased significantly (p = 0.016). CONCLUSIONS: Our study showed a significant increase in CD4+ T lymphocyte levels in the synbiotic group, which could delay the initiation of antiretroviral therapy and decrease costs in countries with limited resources

    ULTRASOUND-ASSISTED EXTRACTION OF OIL FROM KIWIFRUIT (Actinidia Deliciosa) SEEDS

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    This study reports experimental kinetic data and modeling for the extraction of oil from kiwifruit seeds by ultrasound-assisted extraction (UAE) with ethanol. The fatty acid profile, tocopherol and total lipids content in the oil obtained were determined. The variables temperature and ultrasonic power were investigated based on the oil extraction yields using a central composite experimental design. The overall yields obtained were compared to conventional Soxhlet extraction with n-hexane and with ethanol. The extractions presented high extraction rates with overall yield ranged between 19 and 33%, and the extraction yields increased with the temperature. The fatty acid profile showed a high content of omega-3 fatty acids (63.20%) and the Vitamin E content was 14.97 ± 0.38 mg/100 g oil, with ɤ-tocopherol constituting 49% of the total tocopherol. A second-order kinetic model was applied to describe the ultrasound extraction process under different conditions. The numerical results were compared with the experimental extraction yields and presented a good correlation. The extraction technique investigated was found to be suitable for extraction of oil from kiwifruit seeds, in which the great potential of kiwifruit oil obtained from UAE was demonstrate

    The preference for and tolerance of exercise intensity: an exploratory analysis of intensity discrepancy in health clubs settings

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    Health clubs are considered one of the most relevant contexts of exercise. However, they suffer from high dropout rates and struggle to keep exercisers enrolled in the long run. Considering the exercise intensity-affect relation, the main objective of this exploratory study was to test the relation of the discrepancy between the intensity traits and current exercise training intensity, and possible differences in subjective vitality, habit, and weekly exercise frequency. A total of 485 participants (female = 274) aged between 18 and 63 years (M = 39.9) enrolled in several activities participated in this study. Descriptive, correlational, and group comparison analyses were developed for study hypothesis testing. Results tend to support that different levels of agreement between the intensity traits and current training intensity have differentiated outcomes. Particularly, having both intensity traits in agreement with current training intensity depicted the most relevant scores for vitality, habit, and exercise frequency. Both traits in disagreement presented the worst scores.info:eu-repo/semantics/publishedVersio

    Lidocaine for systemic sclerosis: a double-blind randomized clinical trial

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    Background: Systemic sclerosis (scleroderma; SSc) is an orphan disease with the highest case-specific mortality of any connective-tissue disease. Excessive collagen deposit in affected tissues is a key for the disease's pathogenesis and comprises most of the clinical manifestations. Lidocaine seems to be an alternative treatment for scleroderma considering that: a) the patient's having excessive collagen deposits in tissues affected by scleroderma; b) the patient's demonstrating increased activity of the enzyme prolyl hydroxylase, an essential enzyme for the biosynthesis of collagen; and c) lidocaine's reducing the activity of prolyl hydroxylase. the aim of this study was to evaluate the efficacy and safety of lidocaine in treating scleroderma.Methods: A randomized double-blind clinical trial included 24 patients with scleroderma randomized to receive lidocaine or placebo intravenously in three cycles of ten days each, with a one-month interval between them. Outcomes: cutaneous (modified Rodnan skin score), oesophageal (manometry) and microvascular improvement (nailfold capillaroscopy); improvement in subjective self-assessment and in quality of life (HAQ).Results: There was no statistically significant difference between the groups for any outcome after the treatment and after 6-months follow-up. Improvement in modified Rodnan skin score occurred in 66.7% and 50% of placebo and lidocaine group, respectively (p = 0.408). Both groups showed an improvement in subjective self-assessment, with no difference between them.Conclusions: Despite the findings of a previous cohort study favouring the use of lidocaine, this study demonstrated that lidocaine at this dosage and means of administration showed a lack of efficacy for treating scleroderma despite the absence of significant adverse effects. However, further similar clinical trials are needed to evaluate the efficacy of lidocaine when administered in different dosages and by other means.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Universidade Federal de São Paulo, Escola Paulista Med UNIFESP EPM, Brazilian Cochrane Ctr, São Paulo, BrazilUniversidade Federal de São Paulo, Escola Paulista Med UNIFESP EPM, Discipline Emergency Med & Evidence Based Med, São Paulo, BrazilUniversidade Federal de São Paulo, Escola Paulista Med UNIFESP EPM, Discipline Rheumatol, São Paulo, BrazilUniv Santo Amaro, Discipline Rheumatol, São Paulo, BrazilUniversidade Federal de São Paulo, Escola Paulista Med UNIFESP EPM, Brazilian Cochrane Ctr, São Paulo, BrazilUniversidade Federal de São Paulo, Escola Paulista Med UNIFESP EPM, Discipline Emergency Med & Evidence Based Med, São Paulo, BrazilUniversidade Federal de São Paulo, Escola Paulista Med UNIFESP EPM, Discipline Rheumatol, São Paulo, BrazilFAPESP: 01-13895-9Web of Scienc

    Polyurethanes from modified castor oil and chitosan. Synthesis, characterization, in vitro degradation, and cytotoxicity

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    [EN] Polyurethanes (PUs) from castor oil (CO), modified CO (MCO) by transesterification reaction, isophorone diisocyanate (IPDI) in an NCO/OH ratio equal to 1, and chitosan (CS) were synthesized to assess their potential as biomaterials. PUs were characterized by Fourier transform infrared spectroscopy, hydroxyl value (ASTM D1957), thermogravimetric analysis, Shore A hardness (ASTM D2240), and scanning electronic microscopy (SEM). Also, contact angle, water retention and in vitro degradation in PBS, and cell viability on fibroblast were performed. The hydroxyl value confirms CO modification, and IR analysis confirms urethane bond formation. The thermal assay does not show new degradation stages and polyol with a high functionality had better hardness performance due to the increase in cross-linking. The micrograph shows micro-phase separation of both polymers. The contact angle shows the hydrophobic surface with an angle over 65°, and the CS and polyol type do not affect swelling and in vitro degradation due to phase separation between both polymers. The cell viability was over 70% in all cases, and solid polymers and degradation products involve non-cytotoxic effects on the samples. The results suggest a potential for these formulations in the biomedical field.The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by Universidad de La Sabana under Grant number ING-160-2015. Also, Jose A. Gomez-Tejedor and Ana Valles-Lluch acknowledge the support of the Spanish Ministry of Economy and Competitiveness (MINECO) through the project DPI2015-65401-C3-2-R (including the FEDER financial support).Arévalo-Alquichire, S.; Ramírez, C.; Andrade, L.; Uscategui, Y.; Diaz, LE.; Gómez-Tejedor, JA.; Vallés Lluch, A.... (2018). Polyurethanes from modified castor oil and chitosan. Synthesis, characterization, in vitro degradation, and cytotoxicity. Journal of Elastomers and Plastics. 50(5):419-434. https://doi.org/10.1177/0095244317729578S41943450

    The Psychedelic State Induced by Ayahuasca Modulates the Activity and Connectivity of the Default Mode Network

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    The experiences induced by psychedelics share a wide variety of subjective features, related to the complex changes in perception and cognition induced by this class of drugs. A remarkable increase in introspection is at the core of these altered states of consciousness. Self-oriented mental activity has been consistently linked to the Default Mode Network (DMN), a set of brain regions more active during rest than during the execution of a goal-directed task. Here we used fMRI technique to inspect the DMN during the psychedelic state induced by Ayahuasca in ten experienced subjects. Ayahuasca is a potion traditionally used by Amazonian Amerindians composed by a mixture of compounds that increase monoaminergic transmission. In particular, we examined whether Ayahuasca changes the activity and connectivity of the DMN and the connection between the DMN and the task-positive network (TPN). Ayahuasca caused a significant decrease in activity through most parts of the DMN, including its most consistent hubs: the Posterior Cingulate Cortex (PCC)/Precuneus and the medial Prefrontal Cortex (mPFC). Functional connectivity within the PCC/Precuneus decreased after Ayahuasca intake. No significant change was observed in the DMN-TPN orthogonality. Altogether, our results support the notion that the altered state of consciousness induced by Ayahuasca, like those induced by psilocybin (another serotonergic psychedelic), meditation and sleep, is linked to the modulation of the activity and the connectivity of the DMN.The Brazilian Federal Agencies: CNPq, CAPES; FINEP; The Sao Paulo State financial agency (FAPESP)
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