Stochastic model for the dynamics of interacting Brownian particles

Using the scheme of mesoscopic nonequilibrium thermodynamics, we construct the one- and two- particle Fokker-Planck equations for a system of interacting Brownian particles. By means of these equations we derive the corresponding balance equations. We obtain expressions for the heat flux and the pressure tensor which enable one to describe the kinetic and potential energy interchange of the particles with the heat bath. Through the momentum balance we analyze in particular the diffusion regime to obtain the collective diffusion coefficient in terms of the hydrodynamic and the effective forces acting on the Brownian particles.Comment: latex fil

Excessive Mechanotransduction in Sensory Neurons Causes Joint Contractures

Distal arthrogryposis (DA) is a collection of rare disorders that are characterized by congenital joint contractures. Most DA mutations are in muscle- and joint-related genes, and the anatomical defects originate cell-autonomously within the musculoskeletal system. However, gain-of-function mutations in PIEZO2, a principal mechanosensor in somatosensation, cause DA subtype 5 (DA5) through unknown mechanisms. We show that expression of a gain-of-function PIEZO2 mutation in proprioceptive sensory neurons that mainly innervate muscle spindles and tendons is sufficient to induce DA5-like phenotypes in mice. Overactive PIEZO2 causes anatomical defects through increased activity within the peripheral nervous system during postnatal development. Furthermore, botulinum toxin (Botox) and a dietary fatty acid that modulates PIEZO2 activity reduce DA5-like deficits. This reveals a role for somatosensory neurons: Excessive mechanosensation within these neurons disrupts musculoskeletal development

Elevated Plasma Endothelin-1 and Pulmonary Arterial Pressure in Children Exposed to Air Pollution

BackgroundControlled exposures of animals and humans to particulate matter (PM) or ozone air pollution cause an increase in plasma levels of endothelin-1, a potent vasoconstrictor that regulates pulmonary arterial pressure.ObjectivesThe primary objective of this field study was to determine whether Mexico City children, who are chronically exposed to levels of PM and O3 that exceed the United States air quality standards, have elevated plasma endothelin-1 levels and pulmonary arterial pressures.MethodsWe conducted a study of 81 children, 7.9 ± 1.3 years of age, lifelong residents of either northeast (n = 19) or southwest (n = 40) Mexico City or Polotitlán (n = 22), a control city with PM and O3 levels below the U.S. air quality standards. Clinical histories, physical examinations, and complete blood counts were done. Plasma endothelin-1 concentrations were determined by immunoassay, and pulmonary arterial pressures were measured by Doppler echocardiography.ResultsMexico City children had higher plasma endothelin-1 concentrations compared with controls (p < 0.001). Mean pulmonary arterial pressure was elevated in children from both northeast (p < 0.001) and southwest (p < 0.05) Mexico City compared with controls. Endothelin-1 levels in Mexico City children were positively correlated with daily outdoor hours (p = 0.012), and 7-day cumulative levels of PM air pollution < 2.5 μm in aerodynamic diameter (PM2.5) before endothelin-1 measurement (p = 0.03).ConclusionsChronic exposure of children to PM2.5 is associated with increased levels of circulating endothelin-1 and elevated mean pulmonary arterial pressure

Células cebadas en pulmón y nervio periférico en la intoxicación crónica con karwinskia humboldtiana en rata wistar: estudios histológico e histoquímico = Lung and peripheral nerve mast cells in chronic intoxication with karwinskia humboldtiana in wistar rat: histological and histochemical Studies

Karwinskia humboldtiana (Kh) es un arbusto venenoso responsable de numerosos casos de intoxicación accidental en humanos. En estudios previos en nuestro laboratorio reportamos un incremento de células cebadas en nervio periférico (NP) durante la intoxicación con Kh, este hallazgo no ha sido reportado previamente en otros órganos durante esta intoxicación por lo que en el presente estudio buscamos la presencia de estas células en otros órganos, además de distinguir subpoblaciones de células cebadas mediante reacciones histoquímicas para la identificación de los gránulos de secreción. El objetivo de este estudio fue evaluar la presencia de células cebadas en órganos distintos al NP y diferenciar histoquímicamente la composición de sus gránulos. Se utilizaron 32 ratas Wistar, se dividieron en cuatro grupos (n= 8) en donde 5 ratas de cada grupo fueron intoxicadas y 3 fueron control no intoxicadas. A las ratas intoxicadas se les administraron por vía oral 3,5 g/kg del fruto seco y molido de Kh fraccionados en 5 dosis de 1,5; 0,5, 0,5; 0,5 y 0,5 g/kg los días 0, 3, 7, 10 y 14 respectivamente. Las ratas control solo recibieron agua. Cada grupo fue sacrificado a diferentes tiempos según la evolución de la parálisis. Se obtuvieron muestras de Hígado, Riñón, Pulmón y SNP, se procesaron hasta obtener bloques de parafina, se obtuvieron cortes y se tiñeron con azul de toluidina, PAS, Azul alciano/PAS y Azul alciano/Safranina. Se identificó la presencia de células cebadas en NP y pulmón con la tinción de azul de toluidina y se realizo un estudio morfométrico observando un incremento progresivo del número de células cebadas por grupo así como variaciones histoquímicas en sus gránulos en cada etapa y órgano analizado, lo que sugiere la participación de las células cebadas y sus secreciones en cada una de las etapas de la intoxicación crónica con el fruto maduro de Kh

Reproductive and seminal characteristics of Pelibuey rams infected with Mycobacterium avium subsp. paratuberculosis in the subclinical stage

Objective: To evaluate the reproductive and seminal characteristics of Pelibuey rams infected with Mycobacterium avium subsp. paratuberculosis in the subclinical phase. Design/methodology/approach: In order to determine whether paratuberculosis (PTB) affects the reproductive variables and seminal quality in Pelibuey rams naturally infected with Mycobacterium avium subsp. paratuberculosis (MAP) in the subclinical phase, weekly evaluations were conducted, over a period of two months, of the variables live weight, scrotal circumference, ejaculation latency and seminal characteristics: volume, pH, masal motility and progressive individual motility, concentration, live spermatozoids and dead spermatozoids, in five rams infected by MAP and a further five uninfected rams, of average weight and age 53.58 kg (± 3.26) and 2.91 years (± 0.59), respectively. Results: PTB was not found to affect the reproductive and seminal variables evaluated. Limitations of the study/implications: It would have been convenient to carry out the evaluation of the seminal characteristics for a longer time, however, the sampling was stopped in order to ensure the animal welfare of the rams as far as possible, since they began to show signs of PTB. Findings/Conclusions: The Pelibuey rams diagnosed with PTB in subclinical phase did not present any effect on the reproductive and seminal characteristics. Meanwhile, reproductive management can be carried out with PTB-infected Pelibuey lambs in a subclinical phase.Objective: To evaluate the reproductive and seminal characteristics of Pelibuey rams infected with Mycobacterium avium subsp. paratuberculosis in the subclinical phase. Design/methodology/approach: In order to determine whether paratuberculosis (PTB) affects the reproductive variables and seminal quality in Pelibuey rams naturally infected with Mycobacterium avium subsp. paratuberculosis (MAP) in the subclinical phase, weekly evaluations were conducted, over a period of two months, of the variables live weight, scrotal circumference, ejaculation latency and seminal characteristics: volume, pH, masal motility and progressive individual motility, concentration, live spermatozoids and dead spermatozoids, in five rams infected by MAP and a further five uninfected rams, of average weight and age 53.58 kg (± 3.26) and 2.91 years (± 0.59), respectively. Results: PTB was not found to affect the reproductive and seminal variables evaluated. Limitations of the study/implications: It would have been convenient to carry out the evaluation of the seminal characteristics for a longer time, however, the sampling was stopped in order to ensure the animal welfare of the rams as far as possible, since they began to show signs of PTB. Findings/Conclusions: The Pelibuey rams diagnosed with PTB in subclinical phase did not present any effect on the reproductive and seminal characteristics. Meanwhile, reproductive management can be carried out with PTB-infected Pelibuey lambs in a subclinical phase

Search for the standard model Higgs boson in the H to ZZ to 2l 2nu channel in pp collisions at sqrt(s) = 7 TeV

A search for the standard model Higgs boson in the H to ZZ to 2l 2nu decay channel, where l = e or mu, in pp collisions at a center-of-mass energy of 7 TeV is presented. The data were collected at the LHC, with the CMS detector, and correspond to an integrated luminosity of 4.6 inverse femtobarns. No significant excess is observed above the background expectation, and upper limits are set on the Higgs boson production cross section. The presence of the standard model Higgs boson with a mass in the 270-440 GeV range is excluded at 95% confidence level.Comment: Submitted to JHE

Search for New Physics with Jets and Missing Transverse Momentum in pp collisions at sqrt(s) = 7 TeV

A search for new physics is presented based on an event signature of at least three jets accompanied by large missing transverse momentum, using a data sample corresponding to an integrated luminosity of 36 inverse picobarns collected in proton--proton collisions at sqrt(s)=7 TeV with the CMS detector at the LHC. No excess of events is observed above the expected standard model backgrounds, which are all estimated from the data. Exclusion limits are presented for the constrained minimal supersymmetric extension of the standard model. Cross section limits are also presented using simplified models with new particles decaying to an undetected particle and one or two jets

Search for anomalous t t-bar production in the highly-boosted all-hadronic final state

A search is presented for a massive particle, generically referred to as a Z', decaying into a t t-bar pair. The search focuses on Z' resonances that are sufficiently massive to produce highly Lorentz-boosted top quarks, which yield collimated decay products that are partially or fully merged into single jets. The analysis uses new methods to analyze jet substructure, providing suppression of the non-top multijet backgrounds. The analysis is based on a data sample of proton-proton collisions at a center-of-mass energy of 7 TeV, corresponding to an integrated luminosity of 5 inverse femtobarns. Upper limits in the range of 1 pb are set on the product of the production cross section and branching fraction for a topcolor Z' modeled for several widths, as well as for a Randall--Sundrum Kaluza--Klein gluon. In addition, the results constrain any enhancement in t t-bar production beyond expectations of the standard model for t t-bar invariant masses larger than 1 TeV.Comment: Submitted to the Journal of High Energy Physics; this version includes a minor typo correction that will be submitted as an erratu