1,472 research outputs found

    The conservation of energy-momentum and the mass for the graviton

    Full text link
    In this work we give special attention to the bimetric theory of gravitation with massive gravitons proposed by Visser in 1998. In his theory, a prior background metric is necessary to take in account the massive term. Although in the great part of the astrophysical studies the Minkowski metric is the best choice to the background metric, it is not possible to consider this metric in cosmology. In order to keep the Minkowski metric as background in this case, we suggest an interpretation of the energy-momentum conservation in Visser's theory, which is in accordance with the equivalence principle and recovers naturally the special relativity in the absence of gravitational sources. Although we do not present a general proof of our hypothesis we show its validity in the simple case of a plane and dust-dominated universe, in which the `massive term' appears like an extra contribution for the energy density.Comment: 9 pages, accepted for publishing in GR

    The improvement of emotion and attention regulation after a 6-week training of focused meditation :

    Get PDF
    Self-regulatory trainings can be an effective complementary treatment for mental health disorders. We investigated the effects of a six-week-focused meditation training on emotion and attention regulation in undergraduates randomly allocated to a meditation, a relaxation, or a wait-list control group. Assessment comprised a discrimination task that investigates the relationship between attentional load and emotional processing and self-report measures. For emotion regulation, results showed greater reduction in emotional interference in the low attentional load condition in meditators, particularly compared to relaxation. Only meditators presented a significant association between amount of weekly practice and the reduction in emotion interference in the task and significantly reduced image ratings of negative valence and arousal, perceived anxiety and difficulty during the task, and state and trait-anxiety. For attention regulation, response bias during the task was analyzed through signal detection theory. After training, meditation and relaxation significantly reduced bias in the high attentional load condition. Importantly, there was a doseresponse effect on general bias: the lowest in meditation, increasing linearly across relaxation and wait-list. Only meditators reduced omissions in a concentrated attention test. Focused meditation seems to be an effective training for emotion and attention regulation and an alternative for treatments in the mental health context

    Suppression of the hemolytic effect of mesoporous silica nanoparticles after protein corona interaction: independence of the surface microchemical environment

    Get PDF
    Mesoporous silica nanoparticles are known to induce the hemolysis of human red blood cells (RBCs) when citotoxicity assays are performed in a phosphate buffer solution (PBS). However, in a more realistic approach, the presence of blood plasma biomolecules must be considered in any nanotoxicological evaluation of porous SiO2 nanoparticles when biomedical applications through intravenous administration are aimed. In this context, it is demonstrated in this work that porous silica nanoparticles do not induce any cytotoxic effect on RBCs when hemolysis assay is done in the presence of blood plasma, regardless the surface charge (positive or negative) of the nanoparticle. The absence of hemolysis is mainly associated with the adsorption of plasma proteins on the nanoparticle surface, which leads to the formation of a stable protein coating (called protein corona or PC) that shields the original microchemical environment of bare nanoparticles.Nanopartículas mesoporosas de sílica são conhecidas por induzirem hemólise de células vermelhas do sangue (RBCs) humano quando ensaios de citotoxicidade são feitos em solução-tampão de fosfato (PBS). Entretanto, em uma abordagem mais realista, a presença de biomoléculas do plasma sanguíneo precisa ser considerada em qualquer avaliação nanotoxicológica de nanopartículas porosas de SiO2 quando se objetiva a sua utilização em aplicações biomédicas através de administração intravenosa. Nesse contexto, demonstrou-se neste trabalho que nanopartículas porosas de sílica não induzem nenhum efeito citotóxico em células vermelhas do sangue quando ensaios de hemólise são feitos na presença de plasma sanguíneo, independentemente da carga superficial (positiva ou negativa) da nanopartícula. A ausência de hemólise está principalmente associada à adsorção de proteínas do plasma sobre a superfície das nanopartículas, levando à formação de um recobrimento proteico estável (denominado protein corona ou PC) que blinda o ambiente microquímico original das nanopartículas.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Universidade Estadual de Campinas Instituto de Química Laboratório de Química do Estado SólidoUniversidade Federal de São Paulo (UNIFESP) Departamento de BioquímicaUniversidade Federal do Ceará Departamento de FísicaUNIFESP, Depto. de BioquímicaSciEL

    Spontaneous vesicle formation in catanionic mixtures of amino acid-based surfactants: Chain length symmetry effects

    Get PDF
    The use of amino acids for the synthesis of novel surfactants with vesicle-forming properties potentially enhances the biocompatibility levels needed for a viable alternative to conventional lipid vesicles. In this work, the formation and characterization of catanionic vesicles by newly synthesized lysine- and serine-derived surfactants have been investigated by means of phase behavior mapping and PFG-NMR diffusometry and cryo-TEM methods. The lysine-derived surfactants are double-chained anionic molecules bearing a pseudogemini configuration, whereas the serine-derived amphiphile is cationic and single-chained. Vesicles form in the cationic-rich side for narrow mixing ratios of the two amphiphiles. Two pairs of systems were studied: one symmetric with equal chain lengths, 2C(12)/C(12), and the other highly asymmetric with 2C(8)/C(16) chains, where the serine-based surfactant has the longest chain. Different mechanisms of the vesicle-to-micelle transition were found, depending on symmetry: the 2C12/C12 system entails limited micellar growth and intermediate phase separation, whereas the 2C(8)/C(16) system shows a continuous transition involving large wormlike micelles. The results are interpreted on the basis of currently available models for the micelle-vesicle transitions and the stabilization of catanionic vesicles (energy of curvature vs mixing entropy)

    COST-EFFECTIVENESS ANALYSIS OF TRASTUZUMAB IN THE TREATMENT OF METASTATIC BREAST CANCER

    Get PDF
    Objective: To perform a cost-effectiveness analysis of pharmacological treatments for MBC in the context of the Brazilian Unified Health System (Sistema Único de Saúde - SUS) by comparing the drugs docetaxel and paclitaxel in isolation and in combination with trastuzumab. Methods: The results for each treatment were simulated using a Markov model and a hypothetical cohort of 1000 women aged 50 years diagnosed with MBC with overexpression of HER2. The progression of MBC was simulated for 48 months and the transitions between health states occurred monthly. A sensitivity analysis was performed. The discount rate considered was 5% per year. Results: The addition of trastuzumab allowed a gain of eight to ten months in the average lifespan after a four-year treatment. The increased threshold allows the increased use of trastuzumab combined with paclitaxel in the treatment of MBC. The combination of trastuzumabwith docetaxel and paclitaxel achieved an effective gain in the survival of patients with MBC, and the average survival time doubled compared with monotherapy. Conclusion: Considering that the costs per quality-adjusted life year (QALY) of these treatment strategies were below the threshold of 3 times the per capita GDP recommended by WHO, both strategies can be considered cost-effective

    Sequence-aware multimodal page classification of Brazilian legal documents

    Full text link
    The Brazilian Supreme Court receives tens of thousands of cases each semester. Court employees spend thousands of hours to execute the initial analysis and classification of those cases -- which takes effort away from posterior, more complex stages of the case management workflow. In this paper, we explore multimodal classification of documents from Brazil's Supreme Court. We train and evaluate our methods on a novel multimodal dataset of 6,510 lawsuits (339,478 pages) with manual annotation assigning each page to one of six classes. Each lawsuit is an ordered sequence of pages, which are stored both as an image and as a corresponding text extracted through optical character recognition. We first train two unimodal classifiers: a ResNet pre-trained on ImageNet is fine-tuned on the images, and a convolutional network with filters of multiple kernel sizes is trained from scratch on document texts. We use them as extractors of visual and textual features, which are then combined through our proposed Fusion Module. Our Fusion Module can handle missing textual or visual input by using learned embeddings for missing data. Moreover, we experiment with bi-directional Long Short-Term Memory (biLSTM) networks and linear-chain conditional random fields to model the sequential nature of the pages. The multimodal approaches outperform both textual and visual classifiers, especially when leveraging the sequential nature of the pages.Comment: 11 pages, 6 figures. This preprint, which was originally written on 8 April 2021, has not undergone peer review or any post-submission improvements or corrections. The Version of Record of this article is published in the International Journal on Document Analysis and Recognition, and is available online at https://doi.org/10.1007/s10032-022-00406-7 and https://rdcu.be/cRvv

    Pharmacokinetic and local toxicity studies of liposome-encapsulated and plain mepivacaine solutions in rats

    Get PDF
    FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOThe pharmacokinetics and the local toxicity of commercial and liposome-encapsulated mepivacaine formulations injected intra-orally in rats were studied. Animals were divided in groups (n=4-6) and treated with 0.1 mL of the formulations: 2% mepivacaine with 1:100,000 epinephrine (MVC(2%EPI)), 3% mepivacaine (MVC(3%)), and 2% liposome-encapsulated mepivacaine (MVC(LUV)). The results showed that the 2% liposome-encapsulated mepivacaine reduced C(max), prolonged AUC(0-infinity) and t(1/2) compared with 3% plain and 2% vasoconstritor-associated mepivacaine, after intraoral injection. In addition, it was also observed that liposomal mepivacaine might protect the tissue against local inflammation evoked by plain or vasoconstrictors-associated mepivacaine, giving supporting evidence for its safety and possible clinical use in dentistry1726876FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP [Proc 06/00121-9]2006/00121-9sem informaçã

    Late Aptian paleoclimate reconstruction of the Brazilian equatorial margin: inferences from palynology

    Get PDF
    This study conducted high-resolution paleoclimatic analyses based on the identification of palynological groups of late Aptian age (biozone Sergipea veriverrucata) in the Bragança and Codó formations within the Bragança–Viseu, São Luís, and Parnaíba basins. The analysis comprised 40 palynological samples, with 200 palynomorphs per slide counted when possible. Bioclimatic analysis was mainly supported by the identification of botanical affinities, and ecological and climatic parameters such as the wet/arid trend (Fs/X), Shannon–Wiener diversity, and indicator species analysis (IndVal) were used. Statistical analyses such as principal component and cluster analyses were employed to support the paleoclimatic interpretations. The study recognized 69 genera distributed among the main groups of living plants, including bryophytes, ferns, lycophytes, gymnosperms, and angiosperms. It was possible to attribute botanical affinity in 94.2 % of the taxa, and nine genera occurred in all sections studied: Afropollis, Araucariacites, Callialasporites, Cicatricosisporites, Classopollis, Cyathidites, Deltoidospora, Equisetosporites, and Verrucosisporites, with Classopollis being the most abundant. The stratigraphic distribution of the bioclimatic groups (hydrophytes, hygrophytes, lowland tropical flora, upland flora, and xerophytes) allowed for the identification of climatic phases: pre-evaporitic, evaporitic, and post-evaporitic. In the pre-evaporitic phase, the most significant abundances were between the hygrophytes and upland flora, indicating a certain level of humidity. Xerophytes were the most abundant in all phases, with a conspicuous increase in the evaporitic phase, reflecting an increase in aridity. In the post-evaporitic phase, there was a significant increase in the upland flora with the return of wetter conditions. This study confirmed an increasing humidity trend in the analyzed sections, probably owing to the influence of the Intertropical Convergence Zone that was already operating during the late Aptian.</p

    Unraveling Vitamin B 12

    Full text link
    corecore