Molecular motors robustly drive active gels to a critically connected state

Living systems often exhibit internal driving: active, molecular processes drive nonequilibrium phenomena such as metabolism or migration. Active gels constitute a fascinating class of internally driven matter, where molecular motors exert localized stresses inside polymer networks. There is evidence that network crosslinking is required to allow motors to induce macroscopic contraction. Yet a quantitative understanding of how network connectivity enables contraction is lacking. Here we show experimentally that myosin motors contract crosslinked actin polymer networks to clusters with a scale-free size distribution. This critical behavior occurs over an unexpectedly broad range of crosslink concentrations. To understand this robustness, we develop a quantitative model of contractile networks that takes into account network restructuring: motors reduce connectivity by forcing crosslinks to unbind. Paradoxically, to coordinate global contractions, motor activity should be low. Otherwise, motors drive initially well-connected networks to a critical state where ruptures form across the entire network.Comment: Main text: 21 pages, 5 figures. Supplementary Information: 13 pages, 8 figure

Self-sustained coherent phonon generation in optomechanical cavities

Optical forces can set tiny objects in states of mechanical self-sustained oscillation, spontaneously generating periodic signals by extracting power from steady sources. Miniaturized self-sustained coherent phonon sources are interesting for applications such as mass-force sensing, intra-chip metrology and intra-chip time-keeping among others. In this paper, we review several mechanisms and techniques that can drive a mechanical mode into the lasing regime by exploiting the radiation pressure force in optomechanical cavities, namely stimulated emission, dynamical back-action, forward stimulated Brillouin scattering and self-pulsing

Comparación en los resultados de pacientes con bronquiolitis manejados con dos diferentes métodos de administrar oxígeno. Informe preliminar de avance del Hospital General de Niños Dr. Pedro de Elizalde

Introducción: La oxigenoterapia en el tratamiento de niños con bronquiolitis puede ser administrada mediantes cánulas nasales con bajo o alto flujo (CNAF). Las CNAF podrían ser una alternativa a la ventilación no invasiva, requiriendo menos recursos que los cuidados intensivos (UCIP). Objetivo: Evaluar si existe diferencia en la proporción de sujetos hospitalizados por bronquiolitis que requiere UCIP o en la duración de su hospitalización, según oxigenoterapia (convencional o CNAF). Métodos: Estudio observacional incluyendo lactantes hospitalizados por bronquiolitis en los meses de junio a agosto de 2017. Los pacientes fueron tratados según el servicio donde se encontraban (las unidades 1, 2 y 3 con oxigenoterapia convencional, y las unidades 4 y 5 con CNAF), al que fueron asignados según disponibilidad de cama. Resultados: Se incluyeron 329 pacientes, con edad promedio de 7,2 meses, que permanecieron hospitalizados 5,9 días y recibieron 4,6 días de oxigenoterapia. Todos recibieron oxigenoterapia, 84 (25,5%) CNAF y 245 (74,5%) convencional. Sólo 10 (3,1%) requirieron UCIP. De los que ingresaron a UCIP 5/84 recibieron CNAF y 5/245 recibieron terapia convencional (OR: 3,1; IC 95%: 0,8-10,7; p=0,07). Los pacientes con CNAF permanecieron significativamente más tiempo hospitalizados (6,9 ± 3,9 días vs. 5,6 ±3,2; p=0,003), luego de controlar por edad, la etiología viral y requerimiento de UCIP. Conclusión: En la población analizada no se observó diferencia en la proporción de pacientes que requirieron UTIP según hubieran recibido oxigenoterapia por CNAF o en forma convencional.Background: Oxygen in bronchiolitis treatment can be delivered by nasal cannulas using low or high flow (HFNC). HFNC can be an alternative to non-invasive ventilation or intensive care (PICU). Objective: To evaluate PICU requirement and length of stay (LOS) according to oxygen delivery method in children hospitalized for bronchiolitis. Methods: Observational study including infants hospitalized for bronchiolitis from June to August 2017. Patients received oxygen based on to the unit in which they were hospitalized (units 1, 2 and 3 received conventional oxygen therapy, while units 4 and 5 received HFNC), assigned according to bed availability. Results: We included 329 patients, aged 7.2 months, with a LOS of 5.9 days, and receiving oxygen for 4.6 days. All of them received oxygen, 84 (25.5%) HFNC and 245 (74,5%) conventional therapy. Only 10 (3.1%) required PICU, 5 using HFNC and 5 on conventional therapy (OR: 3,1; 95%IC: 0.8-10.7; p=0.07). After controlling for age, viral etiology and PICU requirement, patients on HFNC showed a significantly longer LOS (6.9 ± 3.9 vs. 5.6 ± 3.2 days; p=0.003). Conclusion: Patients who received oxygen trough HFNC required PICU less frequently than those in conventional therapy but showed a longer length of stay.Fil: Potasnik, J.. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños Pedro Elizalde (ex Casa Cuna); ArgentinaFil: Golubicki, A.. Ministerio de Salud de la Nación; ArgentinaFil: Fernandez, A.. Gobierno de la Ciudad Autonoma de Buenos Aires. Hospital General de Agudos Carlos Durand.; ArgentinaFil: Raiden, Silvina Claudia. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños Pedro Elizalde (ex Casa Cuna); Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; ArgentinaFil: Sosa, R.. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños Pedro Elizalde (ex Casa Cuna); ArgentinaFil: Gonzalez, N.. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños Pedro Elizalde (ex Casa Cuna); ArgentinaFil: Cairoli, H.. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños Pedro Elizalde (ex Casa Cuna); ArgentinaFil: De Lillo, L.. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños Pedro Elizalde (ex Casa Cuna); ArgentinaFil: Sanluis Fenelli, G.. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños Pedro Elizalde (ex Casa Cuna); ArgentinaFil: Planovsky, H.. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños Pedro Elizalde (ex Casa Cuna); ArgentinaFil: Checacci, E.. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños Pedro Elizalde (ex Casa Cuna); ArgentinaFil: Lopez, M.. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños Pedro Elizalde (ex Casa Cuna); ArgentinaFil: Gigliotti, E.. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños Pedro Elizalde (ex Casa Cuna); ArgentinaFil: Torres, F.. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños Pedro Elizalde (ex Casa Cuna); ArgentinaFil: Ferrero, F.. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños Pedro Elizalde (ex Casa Cuna); Argentin

Search for squarks and gluinos in events with isolated leptons, jets and missing transverse momentum at s√=8 TeV with the ATLAS detector

The results of a search for supersymmetry in final states containing at least one isolated lepton (electron or muon), jets and large missing transverse momentum with the ATLAS detector at the Large Hadron Collider are reported. The search is based on proton-proton collision data at a centre-of-mass energy s√=8 TeV collected in 2012, corresponding to an integrated luminosity of 20 fb−1. No significant excess above the Standard Model expectation is observed. Limits are set on supersymmetric particle masses for various supersymmetric models. Depending on the model, the search excludes gluino masses up to 1.32 TeV and squark masses up to 840 GeV. Limits are also set on the parameters of a minimal universal extra dimension model, excluding a compactification radius of 1/R c = 950 GeV for a cut-off scale times radius (ΛR c) of approximately 30

Condiciones laborales de los pacientes con ERCnT que asisten a la Unidad Nacional de Atención al Enfermo renal Crónico (Unaerc)

La enfermedad renal crónica de causa no tradicional (ERCnT) es de etiología multifactorial y no se conoce con exactitud el factor que la provoca. Se asocia a factores como trabajo agrícola, estrés térmico, deshidratación y exposición a químicos. Este estudio transversal describe las condiciones laborales de pacientes con ERCnT que asisten a terapia de hemodiálisis en Unaerc (previo al inicio del tratamiento), y los factores que pudieron predisponer la enfermedad. Se utilizó un diseño de muestreo no probabilístico por cuotas, obteniendo una muestra de 107 pacientes sin antecedentes de diabetes mellitus y < 60 años. Los resultados mostraron que el 76.6 % (82/107) fueron de género masculino, el 26.2 % (28/107), diagnosticados entre 31-40 años y el 38.3 % (41/107) provenían del departamento de Guatemala. El 24.3 % (26/107) y el 15.9 % (17/107) se dedicaban a trabajos agrícolas y al comercio, respectivamente. La mayoría (26.9 %; 7/26) de los trabajadores agrícolas se dedicaban al corte de caña de azúcar; el 57.9 % (62/107) trabajaban para una institución, donde solamente un 17.8 % (19/107) tenían contrato escrito. El 43 % (46/107) trabajaban 6 días/semana, el 57.9 % (62/107) realizaban jornadas de > 8 h/día y el 56.1 % (60/107) no tenían horas extras remuneradas. El 68.2 % (73/107) ganaba menos del salario mínimo y el 70.1 % (75/107) no recibía prestaciones laborales. El 36.4 % (39/107) estuvo expuesto a químicos, el 91.5 % (98/107) se exponía 8 h/día al sol. Solamente 83.2 % (89/107) descansaba durante la jornada laboral

Mathematical model of a telomerase transcriptional regulatory network developed by cell-based screening: analysis of inhibitor effects and telomerase expression mechanisms

Cancer cells depend on transcription of telomerase reverse transcriptase (TERT). Many transcription factors affect TERT, though regulation occurs in context of a broader network. Network effects on telomerase regulation have not been investigated, though deeper understanding of TERT transcription requires a systems view. However, control over individual interactions in complex networks is not easily achievable. Mathematical modelling provides an attractive approach for analysis of complex systems and some models may prove useful in systems pharmacology approaches to drug discovery. In this report, we used transfection screening to test interactions among 14 TERT regulatory transcription factors and their respective promoters in ovarian cancer cells. The results were used to generate a network model of TERT transcription and to implement a dynamic Boolean model whose steady states were analysed. Modelled effects of signal transduction inhibitors successfully predicted TERT repression by Src-family inhibitor SU6656 and lack of repression by ERK inhibitor FR180204, results confirmed by RT-QPCR analysis of endogenous TERT expression in treated cells. Modelled effects of GSK3 inhibitor 6-bromoindirubin-3′-oxime (BIO) predicted unstable TERT repression dependent on noise and expression of JUN, corresponding with observations from a previous study. MYC expression is critical in TERT activation in the model, consistent with its well known function in endogenous TERT regulation. Loss of MYC caused complete TERT suppression in our model, substantially rescued only by co-suppression of AR. Interestingly expression was easily rescued under modelled Ets-factor gain of function, as occurs in TERT promoter mutation. RNAi targeting AR, JUN, MXD1, SP3, or TP53, showed that AR suppression does rescue endogenous TERT expression following MYC knockdown in these cells and SP3 or TP53 siRNA also cause partial recovery. The model therefore successfully predicted several aspects of TERT regulation including previously unknown mechanisms. An extrapolation suggests that a dominant stimulatory system may programme TERT for transcriptional stability

Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV

The polarizations of promptly produced χ_(c1) and χ_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8  TeV. The χ_c states are reconstructed via their radiative decays χ_c → J/ψγ, with the photons being measured through conversions to e⁺e⁻, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_(c2) to χ_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ → μ⁺μ⁻ decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum

Randomized Clinical Trials of obesity treatments in Mexican population. Systematic Review and Meta-Analysis

Background: Mexicans and Mexican Americans share similar culture, genetic background, and predisposition for obesity and diabetes. Randomized clinical trials (RCT) assessing obesity treatments (ObT) are reliable to assess efficacy. To date, there is no systematic review to investigate ObT tested by RCT in Mexican adults. Methods: We conducted systematic searches in Pubmed, Scopus, and Web of Science to retrieve ObT RCT from 1990 to 2019. The ObT included alternative medicine, pharmacological, nutritional, behavioral, and surgical interventions. The analyzed RCT were at least three months of duration, and reported: BMI, weight, waist circumference, triglycerides, glucose and blood pressure. Results: We found 634 entries; after removal of duplicates and exclusions based on eligibility criteria, we analyzed 43 and 2 multinational-collaborative studies. Most of the national studies had small sample sizes, and did not have replications from other studies. The nutrition/behavioral interventions were difficult to blind, and most studies had medium to high risk of bias. Random effects meta-analysis of nutritional/behavioral interventions and medications showed effects on BMI, waist circumference, and blood pressure. Simple measures like plain water instead of sweet beverages decreased triglycerides and systolic blood pressure. Participants with obesity and hypertension had beneficial effects with antioxidants, and the treatment with insulin increased weight in those with T2D. Conclusions: The RCT’s in Mexico reported effects on metabolic components despite small sample sizes and lack of replication. In the future we should analyze ObT in population living on the U.S.-Mexico border; therefore, bi-national collaboration is desirable to disentangle cultural effects on ObT response

Looking for Crumbs in the Obesity Forest: Anti-obesity Interventions and Obesity-Associated Cardiometabolic Traits in the Mexican Population. History and Systematic Review With Meta-Analyses

Mexicans and Mexican Americans share culture, genetic background, and predisposition for chronic complications associated with obesity and diabetes making imperative efficacious treatments and prevention. Obesity has been treated for centuries focused-on weight loss while other treatments on associated conditions like gout, diabetes (T2D), and hypertriglyceridemia. To date, there is no systematic review that synthesizes the origin of obesity clinics in Mexico and the efforts to investigate treatments for obesity tested by randomized clinical trials (RCT). We conducted systematic searches in Pubmed, Scopus, and Web of Science to retrieve anti-obesity RCT through 2019 and without an inferior temporal limit. The systematic review included RCT of anti-obesity treatments in the Mexican adult population, covering alternative medicine, pharmacological, nutritional, behavioral, and surgical interventions reporting metabolism-associated traits such as BMI, weight, waist circumference, triglycerides, glucose, among others. Only the studies with at least 3 months of treatment were included in the meta-analyses in order to reduce placebo effects. We found 634 entries, after removal of duplicates and screening the studies based on eligibility criteria, we analyzed 43 national, and 2 multinational-collaborative studies. Most of the national studies had small sample sizes, and the implemented strategies do not have replications in the population. The nutrition/behavioral interventions were difficult to blind, and most studies have medium-to-high risk of bias. Nutritional/behavioral interventions and medications showed effects on BMI, waist circumference, and blood pressure. Simple measures like pure water instead of sweet beverages decrease triglycerides and systolic blood pressure. Dark chocolate showed the highest effect for BMI and high blood pressure, and treatment with insulin increased weight in those with T2D. The study of obesity in Mexico has been on-going for more than four decades, the interest on RCT just increased until this millennium, but with small sample sizes and lack of replication. The interventions affect different cardiometabolic associated traits, which should be analyzed in detail in the population living near the Mexico-U.S. border; therefore, bi-national collaboration is desirable to disentangle the cultural effects on this population\u27s treatment response