1,390 research outputs found

    Peptídeos antimicrobianos de mamíferos: potencial e limitaçÔes para o tratamento de infecçÔes por Staphylococcus aureus.

    Get PDF
    Antimicrobial peptides (AMPs) are small molecules produced by virtually all living organisms as a part of the innate immune system. They present a broad spectrum antimicrobial activity against a myriad of microorganisms, but also anti-inflammatory, immunomodulatory and antitumor effects, among others. Therefore, it was our objective to compile and analyze the current information about natural and synthetic AMPs, regarding their general mechanisms of action, potentials, and limitations for clinical use, especially for the treatment of Staphylococcus aureus infections. Furthermore, we intended to briefly discuss new routes of administration and the emergence of bacterial resistance to AMPs. To do so, two databases, PubMed and Scopus, and the keywords “Staphylococcus aureus”, “antimicrobial peptide” and “novel antibiotics” were used, and the articles were filtered by the English language for the period between 2011 and 2016. We found that AMPs possess different properties, with characteristic antimicrobial activities and secondary effects. Moreover, we also pointed some modifications that could be used to design new AMPs and different routes of administration that could be used to improve AMP capacity or to adapt it to a specific purpose, such as preventing biofilm formation in catheters or treating a specific disease. On the other hand, they also present limitations that include: development of bacterial resistance, cytotoxicity, and reduced stability, sometimes lower efficacy when compared to the actual treatment, high costs of production and also some inconsistent results between articles, which we believe that may be related to differences in methods and/or strains of S. aureus investigated.PeptĂ­deos antimicrobianos (AMPs) sĂŁo pequenas molĂ©culas conservadas evolutivamente e encontradas virtualmente em todos os organismos vivos como parte de sua imunidade inata. Eles possuem um amplo espectro de atividade antimicrobiana contra diversos microrganismos, mas tambĂ©m ação anti-inflamatĂłria, imunomodulatĂłria, antitumoral, dentre outros efeitos. Desse modo, nosso objetivo foi compilar e analisar as informaçÔes mais atuais sobre AMPs naturais e sintĂ©ticos, considerando seus mecanismos gerais de ação, bem como seu potencial e limitaçÔes para uso clĂ­nico, especialmente no tratamento de infecçÔes por Staphylococcus aureus. AlĂ©m disso, discutimos brevemente o uso de novas vias de administração e a possibilidade do desenvolvimento de resistĂȘncia bacteriana aos AMPs. Para tanto, foram usadas duas bases de dados, PubMed e Scopus e os descritores “Staphylococcus aureus”, “peptĂ­deos antimicrobianos” e “novos antibiĂłticos”. Os artigos foram filtrados para a lĂ­ngua inglesa e foram selecionadas publicaçÔes entre 2011 e 2016. Os resultados foram em sua maioria compatĂ­veis com o que se obteve em revisĂ”es prĂ©vias, a saber, que existe uma grande variedade de AMPs, cada qual com caracterĂ­sticas, atividades antimicrobianas e efeitos secundĂĄrios especĂ­ficos. Ademais, tambĂ©m foram apontadas modificaçÔes que podem ser usadas para o planejamento de novos AMPs e diferentes vias de administração que podem ser usadas para aprimorar os potenciais de um AMP, ou adaptĂĄ-lo para um propĂłsito especĂ­fico, como a prevenção de formação de biofilmes em cateteres ou no tratamento de uma doença especĂ­fica. Por outro lado, eles tambĂ©m possuem limitaçÔes, que incluem: desenvolvimento de resistĂȘncia bacteriana, citotoxicidade e reduzida estabilidade, eventualmente baixa eficĂĄcia quando comparados ao tratamento atual, elevados custos de produção, e mesmo inconsistĂȘncias de resultados entre artigos, o que acreditamos estar relacionado a diferenças no mĂ©todo e/ou a cepa de S. aureus usados

    Non epileptogenic Rasmussen`s encephalitis: a case report

    Get PDF
    Introduction: Rasmussen's encephalitis (RE) is a very rare chronic inflammatory unilateral encephalopathy with still unknown etiology. It predominantly affects children under the age of 10, but can also affect adolescents and adults. Current evidence on possible etiologies are divided in two main theories. The first one is based on brain inflammation caused by a reaction to a foreign antigen. The second one is based on an autoimmune disease that is limited to a single hemisphere of the brain. The common presentation is intractable and frequent focal motor seizures, often associated with progressive neurological decline, and progressive unilateral focal cortical atrophy. Progression of the inflammatory process in MRI is considered a good biomarker in RE. Objectives: Report a rare case of a female infant presenting atypical manifestations of uncommon symptoms without seizures caused by Rasmussen's encephalitis. Case Report: A ten-year-old right-handed female presented to the emergency department with sudden onset of abnormal involuntary movements of the right upper and lower limbs, face paresia of the same side and loss of attention without loss of consciousness. The involuntary contractions were brief, random, irregular, and worsened with activity, along with a positive milkmaid grip sign. She also displayed reduced movement speed and hyperactive biceps, triceps, patellar and ankle jerk reflexes. Associated with the motor abnormalities, the girl presented with a recent but progressive decrease in cognitive functions, which caused a decline in school performance and impaired reasoning, and affective blunting. She had no sign of previous neuropsychomotor development abnormality. She was taken to a quaternary hospital where a MRI and a CT of the brain were performed. MRI showed atrophy of the left cerebral hemisphere, predominantly in the operculum and head of the caudate nucleus, hypersignal in the insular cortex and adjacent white matter. CT presented with hypoattenuation of the left frontal lobe and parieto-occipital white matter associated with atrophy of the head of the caudate nucleus of the same side and enlargement of the adjacent fissures and sulcus. A subsequent PET-CT showed a left cerebral hemisphere hypometabolism, predominantly in the basal ganglia, temporal, frontal and insular lobes. Functional evaluation detected diffuse unilateral disorganization of brain electric activity, but no epileptic paroxysmal discharges were found on the electroencephalogram. After hospitalization, human immunoglobulin at the dose 2g/kg/day was used for five days. The girl remained stable, with no complications. After sixteen days, she was discharged with a rehabilitation program and follow-up care

    Optimasi Portofolio Resiko Menggunakan Model Markowitz MVO Dikaitkan dengan Keterbatasan Manusia dalam Memprediksi Masa Depan dalam Perspektif Al-Qur`an

    Full text link
    Risk portfolio on modern finance has become increasingly technical, requiring the use of sophisticated mathematical tools in both research and practice. Since companies cannot insure themselves completely against risk, as human incompetence in predicting the future precisely that written in Al-Quran surah Luqman verse 34, they have to manage it to yield an optimal portfolio. The objective here is to minimize the variance among all portfolios, or alternatively, to maximize expected return among all portfolios that has at least a certain expected return. Furthermore, this study focuses on optimizing risk portfolio so called Markowitz MVO (Mean-Variance Optimization). Some theoretical frameworks for analysis are arithmetic mean, geometric mean, variance, covariance, linear programming, and quadratic programming. Moreover, finding a minimum variance portfolio produces a convex quadratic programming, that is minimizing the objective function ðð„with constraintsð ð ð„ „ ðandðŽð„ = ð. The outcome of this research is the solution of optimal risk portofolio in some investments that could be finished smoothly using MATLAB R2007b software together with its graphic analysis

    Search for new particles in events with energetic jets and large missing transverse momentum in proton-proton collisions at root s=13 TeV

    Get PDF
    A search is presented for new particles produced at the LHC in proton-proton collisions at root s = 13 TeV, using events with energetic jets and large missing transverse momentum. The analysis is based on a data sample corresponding to an integrated luminosity of 101 fb(-1), collected in 2017-2018 with the CMS detector. Machine learning techniques are used to define separate categories for events with narrow jets from initial-state radiation and events with large-radius jets consistent with a hadronic decay of a W or Z boson. A statistical combination is made with an earlier search based on a data sample of 36 fb(-1), collected in 2016. No significant excess of events is observed with respect to the standard model background expectation determined from control samples in data. The results are interpreted in terms of limits on the branching fraction of an invisible decay of the Higgs boson, as well as constraints on simplified models of dark matter, on first-generation scalar leptoquarks decaying to quarks and neutrinos, and on models with large extra dimensions. Several of the new limits, specifically for spin-1 dark matter mediators, pseudoscalar mediators, colored mediators, and leptoquarks, are the most restrictive to date.Peer reviewe

    Measurement of t(t)over-bar normalised multi-differential cross sections in pp collisions at root s=13 TeV, and simultaneous determination of the strong coupling strength, top quark pole mass, and parton distribution functions

    Get PDF
    Peer reviewe

    Combined searches for the production of supersymmetric top quark partners in proton-proton collisions at root s=13 TeV

    Get PDF
    A combination of searches for top squark pair production using proton-proton collision data at a center-of-mass energy of 13 TeV at the CERN LHC, corresponding to an integrated luminosity of 137 fb(-1) collected by the CMS experiment, is presented. Signatures with at least 2 jets and large missing transverse momentum are categorized into events with 0, 1, or 2 leptons. New results for regions of parameter space where the kinematical properties of top squark pair production and top quark pair production are very similar are presented. Depending on themodel, the combined result excludes a top squarkmass up to 1325 GeV for amassless neutralino, and a neutralinomass up to 700 GeV for a top squarkmass of 1150 GeV. Top squarks with masses from 145 to 295 GeV, for neutralino masses from 0 to 100 GeV, with a mass difference between the top squark and the neutralino in a window of 30 GeV around the mass of the top quark, are excluded for the first time with CMS data. The results of theses searches are also interpreted in an alternative signal model of dark matter production via a spin-0 mediator in association with a top quark pair. Upper limits are set on the cross section for mediator particle masses of up to 420 GeV

    Search for heavy resonances decaying to two Higgs bosons in final states containing four b quarks

    Get PDF
    A search is presented for narrow heavy resonances X decaying into pairs of Higgs bosons (H) in proton-proton collisions collected by the CMS experiment at the LHC at root s = 8 TeV. The data correspond to an integrated luminosity of 19.7 fb(-1). The search considers HH resonances with masses between 1 and 3 TeV, having final states of two b quark pairs. Each Higgs boson is produced with large momentum, and the hadronization products of the pair of b quarks can usually be reconstructed as single large jets. The background from multijet and t (t) over bar events is significantly reduced by applying requirements related to the flavor of the jet, its mass, and its substructure. The signal would be identified as a peak on top of the dijet invariant mass spectrum of the remaining background events. No evidence is observed for such a signal. Upper limits obtained at 95 confidence level for the product of the production cross section and branching fraction sigma(gg -> X) B(X -> HH -> b (b) over barb (b) over bar) range from 10 to 1.5 fb for the mass of X from 1.15 to 2.0 TeV, significantly extending previous searches. For a warped extra dimension theory with amass scale Lambda(R) = 1 TeV, the data exclude radion scalar masses between 1.15 and 1.55 TeV

    An embedding technique to determine ττ backgrounds in proton-proton collision data

    Get PDF
    An embedding technique is presented to estimate standard model tau tau backgrounds from data with minimal simulation input. In the data, the muons are removed from reconstructed mu mu events and replaced with simulated tau leptons with the same kinematic properties. In this way, a set of hybrid events is obtained that does not rely on simulation except for the decay of the tau leptons. The challenges in describing the underlying event or the production of associated jets in the simulation are avoided. The technique described in this paper was developed for CMS. Its validation and the inherent uncertainties are also discussed. The demonstration of the performance of the technique is based on a sample of proton-proton collisions collected by CMS in 2017 at root s = 13 TeV corresponding to an integrated luminosity of 41.5 fb(-1).Peer reviewe

    MUSiC : a model-unspecific search for new physics in proton-proton collisions at root s=13TeV

    Get PDF
    Results of the Model Unspecific Search in CMS (MUSiC), using proton-proton collision data recorded at the LHC at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb(-1), are presented. The MUSiC analysis searches for anomalies that could be signatures of physics beyond the standard model. The analysis is based on the comparison of observed data with the standard model prediction, as determined from simulation, in several hundred final states and multiple kinematic distributions. Events containing at least one electron or muon are classified based on their final state topology, and an automated search algorithm surveys the observed data for deviations from the prediction. The sensitivity of the search is validated using multiple methods. No significant deviations from the predictions have been observed. For a wide range of final state topologies, agreement is found between the data and the standard model simulation. This analysis complements dedicated search analyses by significantly expanding the range of final states covered using a model independent approach with the largest data set to date to probe phase space regions beyond the reach of previous general searches.Peer reviewe

    Measurement of prompt open-charm production cross sections in proton-proton collisions at root s=13 TeV

    Get PDF
    The production cross sections for prompt open-charm mesons in proton-proton collisions at a center-of-mass energy of 13TeV are reported. The measurement is performed using a data sample collected by the CMS experiment corresponding to an integrated luminosity of 29 nb(-1). The differential production cross sections of the D*(+/-), D-+/-, and D-0 ((D) over bar (0)) mesons are presented in ranges of transverse momentum and pseudorapidity 4 < p(T) < 100 GeV and vertical bar eta vertical bar < 2.1, respectively. The results are compared to several theoretical calculations and to previous measurements.Peer reviewe
    • 

    corecore