Probability of osteoporotic vertebral fractures assessment based on DXA measurements and finite element simulation

Osteoporotic vertebral fractures represent major cause of disability, loss of quality of life and even mortality among the elderly population. Decisions on drug therapy are based on the assessment of risk factors for fracture, from bone mineral density measurements. The combination of biomechanical models with clinical studies could better estimate bone strength and support the specialists in their decision. A model to assess the probability of fracture, based on the Damage and Fracture Mechanics has been developed, evaluating the mechanical magnitudes involved in the fracture process from clinical bone mineral density measurements. The model is intended for simulating the degenerative process in the skeleton, with the consequent lost of bone mass and hence the decrease of its mechanical resistance which enables the fracture due to different traumatisms. Clinical studies were chosen, both in non-treatment conditions and receiving drug therapy, and fitted to specific patients according their actual bone mineral density measures. The predictive model is applied in a finite element simulation of the lumbar spine. The fracture zone would be determined according loading scenario (fall, impact, accidental loads, etc.), using the mechanical properties of bone obtained from the evolutionary model corresponding to the considered time. Bone mineral density evolution in untreated patients and in those under different treatments was analyzed. Evolutionary curves of fracture probability were obtained from the evolution of mechanical damage. The evolutionary curve of the untreated group of patients presented a marked increase of the fracture probability, while the curves of patients under drug treatment showed variable decreased risks, depending on the therapy type. The finite element model allowed obtaining detailed maps of damage and fracture probability, identifying high-risk local zones at vertebral body, which are the usual localization of osteoporotic vertebral fractures. The developed model is suitable for being used in individualized cases. The model might better identify at-risk individuals in early stages of osteoporosis and might be helpful for treatment decisions

Cementless Hydroxyapatite Coated Hip Prostheses

More than twenty years ago, hydroxyapatite (HA), calcium phosphate ceramics, was introduced as a coating for cementless hip prostheses. The choice of this ceramic is due to its composition being similar to organic apatite bone crystals. This ceramic is biocompatible, bioactive, and osteoconductive. These qualities facilitate the primary stability and osseointegration of implants. Our surgical experience includes the implantation of more than 4,000 cementless hydroxyapatite coated hip prostheses since 1990. The models implanted are coated with HA in the acetabulum and in the metaphyseal area of the stem. The results corresponding to survival and stability of implants were very satisfactory in the long-term. From our experience, HA-coated hip implants are a reliable alternative which can achieve long term survival, provided that certain requirements are met: good design selection, sound choice of bearing surfaces based on patient life expectancy, meticulous surgical technique, and indications based on adequate bone quality

Patients with acute heart failure discharged from the emergency department and classified as low risk by the MEESSI score (multiple risk estimate based on the Spanish emergency department scale): prevalence of adverse events and predictability

Objetivo. Investigar la tasa de eventos adversos en pacientes con insuficiencia cardiaca aguda (ICA) clasificados de bajo riesgo por la escala MEESSI y dados de alta desde urgencias, la capacidad discriminativa de dicha escala para estos eventos en dichos pacientes y las variables asociadas. Método. Se estratificó el riesgo de los pacientes del Registro EAHFE (cohortes 2-5) mediante la escala MEESSI y se analizaron los clasificados de bajo riesgo dados de alta desde urgencias. Se investigó la mortalidad por cualquier causa a 30 días (M-30d), la revisita a urgencias por ICA a 7 días (REV-7d) y la revisita a urgencias u hospitalización por ICA a 30 días (REV-H-30d). Se calculó el área bajo la curva (ABC) de la característica operativa del receptor (COR) de la escala MEESSI para estos eventos. Se analizó la relación entre 42 variables y RV-7d y RV-H-30d mediante regresión logística multivariable. Resultados. Se incluyeron 1028 pacientes. La M-30d fue 1,6% (IC 95%: 0,9-2,5), la REV-7d fue 8,0% (6,4-9,8) y la REV-H-30d fue 24,7% (22,1-25,7). El ABC ROC de la puntuación MEESSI para discriminar estos eventos adversos fue 0,69 (0,58-0,80), 0,56 (0,49-0,63) y 0,54 (0,50-0,59), respectivamente. Se asociaron con RV-7d: tratamiento diurético crónico (OR 2,45; 1,01-5,98), hemoglobina < 110 g/L (1,68; 1,02-2,75) y tratamiento diurético intravenoso en urgencias (0,53; 0,31-0,90). Se asociaron con REV-H-30d: arteriopatía periférica (1,74; 1,01-3,00), episodios previos de ICA (1,42; 1,02-1,98), tratamiento crónico con inhibidores de receptores mineralocorticoides (1,71; 1,09-2,67), índice de Barthel en urgencias < 90 puntos (1,48; 1,07-2,06) y tratamiento diurético intravenoso en urgencias (0,58; 0,40-0,84). Conclusiones. Los pacientes con ICA de bajo riesgo dados de alta desde urgencias presentan tasas de eventos adversos cercanas a los estándares recomendados internacionalmente. La escala MEESSI, diseñada para predecir M-30d, tiene escasa capacidad predictiva para REV-7d y REV-H-30d en los pacientes de bajo riesgo. Este estudio describe otros factores asociados a tales eventos

Measurement of the top quark forward-backward production asymmetry and the anomalous chromoelectric and chromomagnetic moments in pp collisions at √s = 13 TeV

Abstract The parton-level top quark (t) forward-backward asymmetry and the anomalous chromoelectric (d̂ t) and chromomagnetic (μ̂ t) moments have been measured using LHC pp collisions at a center-of-mass energy of 13 TeV, collected in the CMS detector in a data sample corresponding to an integrated luminosity of 35.9 fb−1. The linearized variable AFB(1) is used to approximate the asymmetry. Candidate t t ¯ events decaying to a muon or electron and jets in final states with low and high Lorentz boosts are selected and reconstructed using a fit of the kinematic distributions of the decay products to those expected for t t ¯ final states. The values found for the parameters are AFB(1)=0.048−0.087+0.095(stat)−0.029+0.020(syst),μ̂t=−0.024−0.009+0.013(stat)−0.011+0.016(syst), and a limit is placed on the magnitude of | d̂ t| &lt; 0.03 at 95% confidence level. [Figure not available: see fulltext.

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

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

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

Peer reviewe

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

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