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1.
Rev Gastroenterol Mex (Engl Ed) ; 89(1): 144-162, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38600006

RESUMO

Coagulation management in the patient with cirrhosis has undergone a significant transformation since the beginning of this century, with the concept of a rebalancing between procoagulant and anticoagulant factors. The paradigm that patients with cirrhosis have a greater bleeding tendency has changed, as a result of this rebalancing. In addition, it has brought to light the presence of complications related to thrombotic events in this group of patients. These guidelines detail aspects related to pathophysiologic mechanisms that intervene in the maintenance of hemostasis in the patient with cirrhosis, the relevance of portal hypertension, mechanical factors for the development of bleeding, modifications in the hepatic synthesis of coagulation factors, and the changes in the reticuloendothelial system in acute hepatic decompensation and acute-on-chronic liver failure. They address new aspects related to the hemorrhagic complications in patients with cirrhosis, considering the risk for bleeding during diagnostic or therapeutic procedures, as well as the usefulness of different tools for diagnosing coagulation and recommendations on the pharmacologic treatment and blood-product transfusion in the context of hemorrhage. These guidelines also update the knowledge regarding hypercoagulability in the patient with cirrhosis, as well as the efficacy and safety of treatment with the different anticoagulation regimens. Lastly, they provide recommendations on coagulation management in the context of acute-on-chronic liver failure, acute liver decompensation, and specific aspects related to the patient undergoing liver transplantation.


Assuntos
Insuficiência Hepática Crônica Agudizada , Transtornos da Coagulação Sanguínea , Humanos , Insuficiência Hepática Crônica Agudizada/complicações , Transtornos da Coagulação Sanguínea/complicações , Transtornos da Coagulação Sanguínea/terapia , Cirrose Hepática/complicações , Cirrose Hepática/terapia , Coagulação Sanguínea , Hemostasia
2.
Sci Total Environ ; 818: 151854, 2022 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-34826482

RESUMO

A recent paper by Beretta-Blanco and Carrasco-Letelier (2021) claims that agricultural eutrophication is not one of the main causes for cyanobacterial blooms in rivers and artificial reservoirs. By combining rivers of markedly different hydrological characteristics e.g., presence/absence and number of dams, river discharge and geological setting, the study speculates about the role of nutrients for modulating phytoplankton chlorophyll-a. Here, we identified serious flaws, from erratic and inaccurate data manipulation. The study did not define how erroneous original dataset values were treated, how the variables below the detection/quantification limit were numerically introduced, lack of mandatory variables for river studies such as flow and rainfall, arbitrary removal of pH > 7.5 values (which were not outliers), and finally how extreme values of other environmental variables were included. In addition, we identified conceptual and procedural mistakes such as biased construction/evaluation of model prediction capability. The study trained the model using pooled data from a short restricted lotic section of the (large) Uruguay River and from both lotic and reservoir domains of the Negro River, but then tested predictability within the (small) Cuareim River. Besides these methodological considerations, the article shows misinterpretations of the statistical correlation of cause and effect neglecting basic limnological knowledge of the ecology of harmful algal blooms (HABs) and international research on land use effects on freshwater quality. The argument that pH is a predictor variable for HABs neglects overwhelming basic paradigms of carbon fluxes and change in pH because of primary productivity. As a result, the article introduces the notion that HABs formation are not related to agricultural land use and water residence time and generate a great risk for the management of surface waterbodies. This reply also emphasizes the need for good practices of open data management, especially for public databases in view of external reproducibility.


Assuntos
Negro ou Afro-Americano , Rios , Monitoramento Ambiental , Eutrofização , Proliferação Nociva de Algas , Humanos , Fósforo/análise , Reprodutibilidade dos Testes , Uruguai
3.
Mikrochim Acta ; 188(9): 302, 2021 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-34417662

RESUMO

An electroanalytical platform capable to take and dilute the sample has been designed in order to fully integrate the different steps of the analytical process in only one device. The concept is based on the addition of glass-fiber pads for sampling and diluting to an electrochemical cell combining a paper-based working electrode with low-cost connector headers as counter and reference electrodes. In order to demonstrate the feasibility of this all-in-one platform for biosensing applications, an enzymatic sensor for glucose determination (requiring a potential as low as -0.1 V vs. gold-plated wire by using ferrocyanide as mediator) was developed. Real food samples, such as cola beverages and orange juice, have been analyzed with the bioelectroanalytical lab-on-paper platform. As a proof-of-concept, and trying to go further in the integration of steps, sucrose was successfully detected by depositing invertase in the sampling strip. This enzyme hydrolyzes sucrose into fructose and glucose, which was determined using the enzymatic biosensor. This approach opens the pathway for the development of devices applying the lab-on-paper concept, saving costs and time, and making possible to perform decentralized analysis with high accuracy.


Assuntos
Técnicas Biossensoriais/métodos , Técnicas Eletroquímicas/métodos , Glucose/análise , Papel , Armoracia/enzimologia , Técnicas Biossensoriais/instrumentação , Bebidas Gaseificadas/análise , Citrus sinensis/química , Técnicas Eletroquímicas/instrumentação , Ferrocianetos/química , Sucos de Frutas e Vegetais/análise , Glucose/química , Glucose Oxidase/química , Peroxidase do Rábano Silvestre/química , Estudo de Prova de Conceito , Sacarose/análise , Sacarose/química , beta-Frutofuranosidase/química
4.
Rev Neurol ; 72(5): 151-156, 2021 Mar 01.
Artigo em Espanhol | MEDLINE | ID: mdl-33616197

RESUMO

INTRODUCTION: The Wada test consists of the selective and reversible inhibition of a cerebral hemisphere by intracarotid injection of amobarbital in order to evaluate the laterality of language and memory. However, there are other anesthetic drugs such as propofol, as an alternative for the test. OBJECTIVE: The objective of the study was to describe the tolerability and adverse effects (AE) of the use of propofol for the Wada test, during the presurgical study of patients with drug-resistant epilepsy. METHODS: Consecutive patients with a diagnosis of drug-resistant structural epilepsy were selected who underwent the Wada test during the pre-surgical study in the period from June 2012 to May 2019. The patients were retrospectively evaluated. The AE were described according to the Mikuni classification, modified by Curot. The variables of sex, age, epileptic foci laterality, language laterality, lesional substrate, etiology and dose of administered Propofol were analyzed for any statistical significance. RESULTS: A total of 74 patients, 40 men (54%), were studied. Forty-seven patients (63.5%) had at least one AE. The mean dose of propofol was 9.23 mg. The most frequent AE were tearing, sweating and red eye, corresponding to group I (57%). One patient developed convulsive status epilepticus, an important AE not previously described during the Wada test. CONCLUSION: Performing the Wada test with propofol causes frequent mild adverse effects, which do not prevent its completion. We describe a case of convulsive status epilepticus as the only serious AE.


TITLE: Tolerabilidad y efectos adversos del propofol en la prueba de Wada.Introducción. La prueba de Wada consiste en la inhibición selectiva y reversible de un hemisferio cerebral mediante la inyección intracarotídea de amobarbital con el objetivo de evaluar la lateralidad del lenguaje y la memoria. Existen otros fármacos anestésicos, como el propofol, como alternativa para la prueba. Objetivo. El objetivo del estudio fue describir la tolerabilidad y los efectos adversos (EA) del uso de propofol para la prueba de Wada durante el estudio prequirúrgico de pacientes con epilepsia farmacorresistente. Pacientes y métodos. Se seleccionó a pacientes con diagnóstico de epilepsia estructural farmacorresistente consecutivos, quienes se sometieron a la prueba de Wada durante el estudio prequirúrgico en el período de junio de 2012 a mayo de 2019. Los pacientes fueron evaluados de manera retrospectiva. Los EA se describieron según la clasificación de Mikuni, modificada por Curot. Se analizaron las variables de sexo, edad, lateralidad del foco epiléptico, lateralidad del lenguaje, sustrato lesional, etiología y dosis de propofol administrada en busca de significación estadística. Resultados. Se estudió a un total de 74 pacientes, de los cuales 40 eran hombres (54%). Cuarenta y siete pacientes (63,5%) tuvieron al menos un EA. La dosis media de propofol fue de 9,23 mg. Los EA más frecuentes fueron lagrimeo, sudoración y ojo rojo, correspondientes al grupo I (57%). Un paciente desarrolló estado epiléptico convulsivo, EA importante no descrito anteriormente durante la prueba de Wada. Conclusión. La realización de la prueba de Wada con propofol ocasiona frecuentes efectos adversos leves, los cuales no impiden su finalización. Describimos un caso de estado epiléptico convulsivo como único EA grave.


Assuntos
Anestésicos Intravenosos/efeitos adversos , Testes Neuropsicológicos , Propofol/efeitos adversos , Adolescente , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Adulto Jovem
7.
Mater Sci Eng C Mater Biol Appl ; 103: 109773, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31349438

RESUMO

The incorporation of nanoparticles inside polymeric matrices has led to the development of multifunctional composites necessary to repair human tissues. The addition of nanoparticles may improve the properties of the composite materials such as surface area, mechanical properties, flexibility, hydrophilicity, electrical conductivity, etc. These properties can help in cellular growth, proliferation and/or differentiation. In this work, scaffolds of polycaprolactone (PCL) and reduced graphite oxide (rGO) were built by electrospinning technique. The ratios of rGO/PCL employed were 0.25, 0.5, 0.75 and 1 wt%. Two different voltage setup (10 and 15 kV) and distance of 10 cm were used for electrospinning. Thermal, mechanical, morphological, electrical, porosity and absorption water tests were made to the scaffolds. Samples electrospun at 10 kV with rGO showed improvement in mechanical properties with an increase of 190% of Young's Modulus in comparison with sample without rGO. Furthermore, samples electrospun at 15 kV showed an important deterioration with the addition of rGO but had an increase in the electrical conductivity and porosity. Overall, the addition of 0.75 and 1 wt% of rGO led to a detriment on properties due to formation of aggregates. The voltage on the electrospinning process plays a very important role in the final properties of the nanocomposites scaffolds of PCL-rGO.


Assuntos
Grafite/química , Nanocompostos/química , Poliésteres/química , Módulo de Elasticidade , Porosidade
8.
Biosens Bioelectron ; 135: 64-70, 2019 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-30999242

RESUMO

In this work, we present a multiplexed (eight simultaneous measurements) paper-based electrochemical device developed in a very simple way and using low-cost materials, such as paper, carbon ink and multifunctional connector headers. Meanwhile, we have also combined the paper-based electrochemical platform with a glass-fiber strip in order to integrate easily a sampling step. Both approaches, simultaneous measuring and sampling, have been applied to the determination of glucose using bienzymatic biosensors. They are fabricated by adsorbing the mixture of enzymes (glucose oxidase and horseradish peroxidase), as well as the ferrocyanide, mediator of the electron transfer, on the paper-based electrode. After drying, the measuring solution (containing either glucose standards or samples) is added and the eight corresponding chronoamperograms are recorded. In the case of the microfluidic approach for sampling purposes, the glass-fiber pad (sampler) is immersed in a container with the solution, which flows by capillarity until it reaches the working electrode. The integration of one more step of the analytical process advances towards real and useful lab-on-a-chip devices. With these designs, a linear range comprised between 0.5 and 15 mM was achieved for glucose determination, with an excellent precision. If the sampler is employed, it is not necessary to use micropipettes and, nevertheless, precise measurements are obtained. The RSD of the slopes obtained for different calibrations performed in different days, with different arrays of electrochemical cells and different solutions is ca. 1%. Accurate results are obtained in the determination of glucose in real samples (orange fruit and cola beverages).


Assuntos
Técnicas Biossensoriais/instrumentação , Glucose/análise , Dispositivos Lab-On-A-Chip , Bebidas/análise , Técnicas Biossensoriais/economia , Técnicas Eletroquímicas/economia , Técnicas Eletroquímicas/instrumentação , Eletrodos , Análise de Alimentos/economia , Análise de Alimentos/instrumentação , Dispositivos Lab-On-A-Chip/economia , Limite de Detecção , Papel
9.
Am J Transplant ; 17(10): 2640-2649, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28371433

RESUMO

Cardiovascular risk remains high in kidney transplant recipients (KTRs) despite improved kidney function after transplant. Urinary markers of kidney fibrosis and injury may help to reveal mechanisms of this risk. In a case-cohort study among stable KTRs who participated in the FAVORIT trial, we measured four urinary proteins known to correlate with kidney tubulointerstitial fibrosis on biopsy (urine alpha 1 microglobulin [α1m], monocyte chemoattractant protein-1 [MCP-1], procollagen type I [PINP] and type III [PIIINP] N-terminal amino peptide) and evaluated associations with cardiovascular disease (CVD) events (n = 300) and death (n = 371). In adjusted models, higher urine α1m (hazard ratio [HR] per doubling of biomarker 1.40 [95% confidence interval [CI] 1.21, 1.62]), MCP-1 (HR 1.18 [1.03, 1.36]), and PINP (HR 1.13 [95% CI 1.03, 1.23]) were associated with CVD events. These three markers were also associated with death (HR per doubling α1m 1.51 [95% CI 1.32, 1.72]; MCP-1 1.31 [95% CI 1.13, 1.51]; PINP 1.11 [95% CI 1.03, 1.20]). Higher concentrations of urine α1m, MCP-1, and PINP may identify KTRs at higher risk for CVD events and death. These markers may identify a systemic process of fibrosis involving both the kidney and cardiovascular system, and give new insights into mechanisms linking the kidney with CVD.


Assuntos
Biomarcadores/urina , Doenças Cardiovasculares/urina , Transplante de Rim , Nefrite Intersticial/urina , Idoso , Doenças Cardiovasculares/epidemiologia , Doenças Cardiovasculares/prevenção & controle , Estudos de Casos e Controles , Feminino , Fibrose , Ácido Fólico/administração & dosagem , Humanos , Transplante de Rim/mortalidade , Masculino , Pessoa de Meia-Idade , Fatores de Risco
10.
Phys Rev Lett ; 118(2): 022003, 2017 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-28128595

RESUMO

The first full amplitude analysis of B^{+}→J/ψϕK^{+} with J/ψ→µ^{+}µ^{-}, ϕ→K^{+}K^{-} decays is performed with a data sample of 3 fb^{-1} of pp collision data collected at sqrt[s]=7 and 8 TeV with the LHCb detector. The data cannot be described by a model that contains only excited kaon states decaying into ϕK^{+}, and four J/ψϕ structures are observed, each with significance over 5 standard deviations. The quantum numbers of these structures are determined with significance of at least 4 standard deviations. The lightest has mass consistent with, but width much larger than, previous measurements of the claimed X(4140) state.

11.
Phytochemistry ; 135: 24-33, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27964835

RESUMO

Water deficiency has become a major issue for modern agriculture as its effects on crop yields and tuber quality have become more pronounced. Potato genotypes more tolerant to water shortages have been identified through assessment of yield and dry matter. In the present study, a combination of metabolite profiling and physiological/agronomical measurements has been used to explore complex system level responses to non-lethal water restriction. The metabolites identified were associated with physiological responses in three different plant tissues (leaf, root and tuber) of five different potato genotypes varying in susceptibility/tolerance to drought. This approach explored the potential of metabolite profiling as a tool to unravel sectors of metabolism that react to stress conditions and could mirror the changes in the plant physiology. The metabolite results showed different responses of the three plant tissues to the water deficit, resulting either in different levels of the metabolites detected or different metabolites expressed. The leaf material displayed the most changes to drought as reported in literature. The results highlighted genotype-specific signatures to water restriction over all three plant tissues suggesting that the genetics can predominate over the environmental conditions. This will have important implications for future breeding approaches.


Assuntos
Solanum tuberosum/química , Estresse Fisiológico , Água/metabolismo , Desidratação , Secas , Regulação da Expressão Gênica de Plantas , Folhas de Planta/metabolismo , Proteínas de Plantas/metabolismo , Raízes de Plantas/metabolismo , Tubérculos/metabolismo , Plantas Geneticamente Modificadas/metabolismo , Solanum tuberosum/genética
12.
Biosens Bioelectron ; 93: 40-45, 2017 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-27856164

RESUMO

In this work we have developed an amperometric enzymatic biosensor in a paper-based platform with a mixed electrode configuration: carbon ink for the working electrode (WE) and metal wires (from a low-cost standard electronic connection) for reference (RE) and auxiliary electrodes (AE). A hydrophobic wax-defined paper area was impregnated with diluted carbon ink. Three gold-plated pins of the standard connection are employed, one for connecting the WE and the other two acting as RE and AE. The standard connection works as a clip in order to support the paper in between. As a proof-of-concept, glucose sensing was evaluated. The enzyme cocktail (glucose oxidase, horseradish peroxidase and potassium ferrocyanide as mediator of the electron transfer) was adsorbed on the surface. After drying, glucose solution was added to the paper, on the opposite side of the carbon ink. It wets RE and AE, and flows by capillarity through the paper contacting the carbon WE surface. The reduction current of ferricyanide, product of the enzymatic reaction, is measured chronoamperometrically and correlates to the concentration of glucose. Different parameters related to the bioassay were optimized, adhering the piece of paper onto a conventional screen-printed carbon electrode (SPCE). In this way, the RE and the AE of the commercial card were employed for optimizing the paper-WE. After evaluating the assay system in the hybrid paper-SPCE cell, the three-electrode system consisting of paper-WE, wire-RE and wire-AE, was employed for glucose determination, achieving a linear range between 0.3 and 15mM with good analytical features and being able of quantifying glucose in real food samples.


Assuntos
Técnicas Biossensoriais , Enzimas Imobilizadas/química , Glucose Oxidase/química , Glucose/isolamento & purificação , Técnicas Eletroquímicas , Glucose/química , Ouro/química , Peroxidase do Rábano Silvestre/química , Papel
13.
Langmuir ; 32(45): 11799-11812, 2016 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-27797530

RESUMO

Dilute isotropic collagen solutions are usually flow processed into monodomain chiral nematic thin films for obtaining highly ordered materials by a multistep process that starts with complex inhomogeneous flow kinematics. Here we present rigorous theory and simulation of the initial precursors during flow steps in cholesteric collagen film formation. We first extract the molecular shape parameter and rotational diffusivity from previously reported simple shear data of dilute collagen solutions, where the former leads the reactive parameter (tumbling function) which determines the net effect of vorticity and strain rate on the average orientation and where the latter establishes the intensity of strain required for flow-birefringence, both crucial quantities for controlled film formation flow. We find that the tumbling function is similar to those of rod-like lyotropic liquid crystalline polymers and hence it is predicted that they would tumble in the ordered high concentration state leading to flow-induced texturing. The previously reported experimental data is well fitted with rotational diffusivities whose order of magnitude is consistent to those of other biomacromolecules. We then investigate the response of the tensor order parameter to complex flow kinematics, ranging from pure vorticity, through simple shear, to extensional flow, as may arise in typical flow casting and film flows. The chosen control variable to produce precursor cholesteric films is the director or average orientation, since the nematic order is set close to typical values found in concentrated cholesteric type I collagen solutions. Using the efficient four-roll mill kinematics, we summarize the para-nematic structure-flow process diagram in terms of the director orientation and flow type. Using analysis and computation, we provide a parametric envelope that is necessary to eventually produce well-aligned cholesteric films. We conclude that extensional flow is an essential ingredient of well-ordered film precursors with required Deborah numbers on the order of unity.


Assuntos
Colágeno/química , Modelos Teóricos , Birrefringência , Simulação por Computador , Reprodutibilidade dos Testes , Soluções/química
14.
Phys Rev Lett ; 117(15): 152003, 2016 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-27768360

RESUMO

The B_{s}^{0}π^{±} invariant mass distribution is investigated in order to search for possible exotic meson states. The analysis is based on a data sample recorded with the LHCb detector corresponding to 3 fb^{-1} of pp collision data at sqrt[s]=7 and 8 TeV. No significant excess is found, and upper limits are set on the production rate of the claimed X(5568) state within the LHCb acceptance. Upper limits are also set as a function of the mass and width of a possible exotic meson decaying to the B_{s}^{0}π^{±} final state. The same limits also apply to a possible exotic meson decaying through the chain B_{s}^{*0}π^{±}, B_{s}^{*0}→B_{s}^{0}γ where the photon is excluded from the reconstructed decays.

15.
Phys Rev Lett ; 117(8): 082003, 2016 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-27588849

RESUMO

A full amplitude analysis of Λ_{b}^{0}→J/ψpπ^{-} decays is performed with a data sample acquired with the LHCb detector from 7 and 8 TeV pp collisions, corresponding to an integrated luminosity of 3 fb^{-1}. A significantly better description of the data is achieved when, in addition to the previously observed nucleon excitations N→pπ^{-}, either the P_{c}(4380)^{+} and P_{c}(4450)^{+}→J/ψp states, previously observed in Λ_{b}^{0}→J/ψpK^{-} decays, or the Z_{c}(4200)^{-}→J/ψπ^{-} state, previously reported in B^{0}→J/ψK^{+}π^{-} decays, or all three, are included in the amplitude models. The data support a model containing all three exotic states, with a significance of more than three standard deviations. Within uncertainties, the data are consistent with the P_{c}(4380)^{+} and P_{c}(4450)^{+} production rates expected from their previous observation taking account of Cabibbo suppression.

16.
Phys Rev Lett ; 117(8): 082002, 2016 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-27588848

RESUMO

The data sample of Λ_{b}^{0}→J/ψpK^{-} decays acquired with the LHCb detector from 7 and 8 TeV pp collisions, corresponding to an integrated luminosity of 3 fb^{-1}, is inspected for the presence of J/ψp or J/ψK^{-} contributions with minimal assumptions about K^{-}p contributions. It is demonstrated at more than nine standard deviations that Λ_{b}^{0}→J/ψpK^{-} decays cannot be described with K^{-}p contributions alone, and that J/ψp contributions play a dominant role in this incompatibility. These model-independent results support the previously obtained model-dependent evidence for P_{c}^{+}→J/ψp charmonium-pentaquark states in the same data sample.

17.
Rev. méd. Chile ; 144(9): 1226-1229, set. 2016. ilus
Artigo em Espanhol | LILACS | ID: biblio-830633

RESUMO

Neuromyelitis optica (NMO) is a severe demyelinating disease of the central nervous system, which preferentially attacks the optic nerve and spinal cord. It is associated with antibodies against aquaporin 4. Morbidity and mortality are higher than in multiple sclerosis and its treatment focuses on immunosuppressive drugs. Immunomodulators are contraindicated. We report a previously healthy 35-year-old man, presenting with NMO concomitantly with systemic lupus erythematosus. His evolution was torpid with three outbreaks in the 10 months after the diagnosis, requiring a first-line therapy with methylprednisolone and cyclophosphamide and then a second-line therapy with rituximab.


Assuntos
Humanos , Masculino , Adulto , Neuromielite Óptica/complicações , Lúpus Eritematoso Sistêmico/complicações , Paresia/complicações , Paresia/tratamento farmacológico , Espasmo/complicações , Espasmo/tratamento farmacológico , Metilprednisolona/uso terapêutico , Neuromielite Óptica/tratamento farmacológico , Antirreumáticos/uso terapêutico , Ciclofosfamida/uso terapêutico , Rituximab/uso terapêutico , Glucocorticoides/uso terapêutico , Lúpus Eritematoso Sistêmico/tratamento farmacológico
18.
Phys Rev Lett ; 117(6): 061803, 2016 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-27541460

RESUMO

The CP asymmetry in the mixing of B_{s}^{0} and B[over ¯]_{s}^{0} mesons is measured in proton-proton collision data corresponding to an integrated luminosity of 3.0 fb^{-1}, recorded by the LHCb experiment at center-of-mass energies of 7 and 8 TeV. Semileptonic B_{s}^{0} and B[over ¯]_{s}^{0} decays are studied in the inclusive mode D_{s}^{∓}µ^{±}ν[over (-)]_{µ}X with the D_{s}^{∓} mesons reconstructed in the K^{+}K^{-}π^{∓} final state. Correcting the observed charge asymmetry for detection and background effects, the CP asymmetry is found to be a_{sl}^{s}=(0.39±0.26±0.20)%, where the first uncertainty is statistical and the second systematic. This is the most precise measurement of a_{sl}^{s} to date. It is consistent with the prediction from the standard model and will constrain new models of particle physics.

19.
Phys Rev Lett ; 116(24): 241801, 2016 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-27367383

RESUMO

Charm meson oscillations are observed in a time-dependent analysis of the ratio of D^{0}→K^{+}π^{-}π^{+}π^{-} to D^{0}→K^{-}π^{+}π^{-}π^{+} decay rates, using data corresponding to an integrated luminosity of 3.0 fb^{-1} recorded by the LHCb experiment. The measurements presented are sensitive to the phase-space averaged ratio of doubly Cabibbo-suppressed to Cabibbo-favored amplitudes r_{D}^{K3π} and the product of the coherence factor R_{D}^{K3π} and a charm mixing parameter y_{K3π}^{'}. The constraints measured are r_{D}^{K3π}=(5.67±0.12)×10^{-2}, which is the most precise determination to date, and R_{D}^{K3π}y_{K3π}^{'}=(0.3±1.8)×10^{-3}, which provides useful input for determinations of the CP-violating phase γ in B^{±}→DK^{±}, D→K^{∓}π^{±}π^{∓}π^{±} decays. The analysis also gives the most precise measurement of the D^{0}→K^{+}π^{-}π^{+}π^{-} branching fraction, and the first observation of D^{0}-D[over ¯]^{0} oscillations in this decay mode, with a significance of 8.2 standard deviations.

20.
Phys Rev Lett ; 116(24): 241601, 2016 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-27367382

RESUMO

Violations of CPT symmetry and Lorentz invariance are searched for by studying interference effects in B^{0} mixing and in B_{s}^{0} mixing. Samples of B^{0}→J/ψK_{S}^{0} and B_{s}^{0}→J/ψK^{+}K^{-} decays are recorded by the LHCb detector in proton-proton collisions at center-of-mass energies of 7 and 8 TeV, corresponding to an integrated luminosity of 3 fb^{-1}. No periodic variations of the particle-antiparticle mass differences are found, consistent with Lorentz invariance and CPT symmetry. Results are expressed in terms of the standard model extension parameter Δa_{µ} with precisions of O(10^{-15}) and O(10^{-14}) GeV for the B^{0} and B_{s}^{0} systems, respectively. With no assumption on Lorentz (non)invariance, the CPT-violating parameter z in the B_{s}^{0} system is measured for the first time and found to be Re(z)=-0.022±0.033±0.005 and Im(z)=0.004±0.011±0.002, where the first uncertainties are statistical and the second systematic.

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