26 research outputs found
Bohm potential is real and its effects are measurable
We analyze Bohm's potential effects both in the realms of Quantum Mechanics
and Optics, as well as in the study of other physical phenomena described in
terms of classical and quantum wave equations. We approach this subject by
using theoretical arguments as well as experimental evidence. We find that the
effects produced by Bohm's potential are both theoretically responsible for the
early success of Quantum Mechanics correctly describing atomic and nuclear
phenomena and, more recently, by confirming surprising accelerating behavior of
free waves and particles experimentally, for instance.Comment: 4 pages, no figures, Accepted in Opti
Propagation of light in linear and quadratic GRIN media: The Bohm potential
It is shown that field propagation in linear and quadratic gradient-index
(GRIN) media obeys the same rules of free propagation in the sense that a field
propagating in free space has a (mathematical) form that may be {\it exported}
to those particular GRIN media. The Bohm potential is introduced in order to
explain the reason of such behavior: it changes the dynamics by modifying the
original potential. The concrete cases of two different initials conditions for
each potential are analyzed
Interaction between VA-ECMO and the right ventricle.
The response of the right ventricle (RV) to the hemodynamic effects of veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is currently unpredictable. We hypothesized that the presence of uni- or bi-ventricular failure before implantation and the cannulation strategy may influence this interaction. We sought to assess the RV performance during VA-ECMO support and identify RV-related predictors of successful weaning.
Changes in RV size and function during VA-ECMO support by echocardiography were retrospectively analyzed in 87 consecutive adult patients between February 2008 and June 2017. Predictors of successful weaning due to myocardial recovery were evaluated by multivariable logistic regression.
RV echocardiographic parameters did not vary significantly during VA-ECMO support and neither after stratification by the type of cannulation or the presence of isolated or biventricular failure. Successful weaning was conditioned by the absence of RV dysfunction before implantation (OR, 14.7; 95% CI, 13.3-140.3; p = 0.025) or in the last day of support (OR, 9.5; 95% CI, 1.6-54; p = 0.011) and was favored by a total or partial recovery of RV function during the assistance (OR, 6.2; 95%CI, 1.7-22.4; p = 0.005). RV improvement was more often observed in patients with acute RV failure and longer support, while VA-ECMO configuration, additional mechanical support, or pharmacological therapy had no effect.
Preservation or improvement of RV function during VA-ECMO is essential for successful weaning. RV echocardiographic performance does not change significantly during VA-ECMO support and is not influenced by cannulation type or the presence of uni- or bi-ventricular failure before implantation.This work was supported by the Alfonso Martin Escudero
Foundation.S
Vascular Inflammation in Subclinical Atherosclerosis Detected by Hybrid PET/MRI
BACKGROUND: Atherosclerosis is a chronic inflammatory disease, but data on arterial inflammation at early stages is limited. OBJECTIVES: The purpose of this study was to characterize vascular inflammation by hybrid 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/magnetic resonance imaging (PET/MRI). METHODS: Carotid, aortic, and ilio-femoral 18F-FDG PET/MRI was performed in 755 individuals (age 40 to 54 years; 83.7% men) with known plaques detected by 2-/3-dimensional vascular ultrasound and/or coronary calcification in the PESA (Progression of Early Subclinical Atherosclerosis) study. The authors evaluated the presence, distribution, and number of arterial inflammatory foci (increased 18F-FDG uptake) and plaques with or without inflammation (coincident 18F-FDG uptake). RESULTS: Arterial inflammation was present in 48.2% of individuals (24.4% femorals, 19.3% aorta, 15.8% carotids, and 9.3% iliacs) and plaques in 90.1% (73.9% femorals, 55.8% iliacs, and 53.1% carotids). 18F-FDG arterial uptakes and plaques significantly increased with cardiovascular risk factors (p < 0.01). Coincident 18F-FDG uptakes were present in 287 of 2,605 (11%) plaques, and most uptakes were detected in plaque-free arterial segments (459 of 746; 61.5%). Plaque burden, defined by plaque presence, number, and volume, was significantly higher in individuals with arterial inflammation than in those without (p < 0.01). The number of plaques and 18F-FDG uptakes showed a positive albeit weak correlation (r = 0.25; p < 0.001). CONCLUSIONS: Arterial inflammation is highly prevalent in middle-aged individuals with known subclinical atherosclerosis. Large-scale multiterritorial PET/MRI allows characterization of atherosclerosis-related arterial inflammation and demonstrates 18F-FDG uptake in plaque-free arterial segments and, less frequently, within plaques. These findings suggest an arterial inflammatory state at early stages of atherosclerosis. (Progression of Early Subclinical Atherosclerosis [PESA]; NCT01410318).The PESA study is cofunded equally by the Centro Nacional de Investigaciones Cardiovasculares (CNIC) and Banco Santander. The study also receives funding from the Instituto de Salud Carlos III (PI15/02019) and the European Regional Development Fund (ERDF) “A way to make Europe.” The CNIC is supported by the Ministerio de Ciencia, Innovación y Universidades, and the Pro CNIC Foundation, and is a Severo Ochoa Center of Excellence (SEV-2015-0505). Dr. Sanchez-González is an employee of Philips Healthcare. Dr. Bueno has received research funding from the Instituto de Salud Carlos III, Spain (PIE16/00021 & PI17/01799), AstraZeneca, Bristol-Myers Squibb, Janssen, and Novartis; has received consulting fees from AstraZeneca, Bayer, Bristol-Myers Squibb-Pfizer, and Novartis; and has received speaking fees or support for attending scientific meetings from AstraZeneca, Bayer, Bristol-Myers Squibb-Pfizer, Novartis, and MEDSCAPE-the heart.org.S
Sensibilidad del test de valoración de la resistencia específica en el fútbol (TVREF) para evaluar la influencia del entrenamiento de pretemporada en la resistencia y capacidad aeróbica de futbolistas profesionales
El test TVREF ha sido utilizado en diferentes estudios científicos sobre valoración de la
condición física en fútbol. Ninguno de ellos ha comprobado la sensibilidad de este test a los efectos del
entrenamiento en fútbol, comparándolo con los resultados de un test continuo. 24 futbolistas de 1ª
División participaron en el estudio, siendo evaluados al inicio y final de una pretemporada de
entrenamiento mediante 2 tests de campo (TVREF y Course Navette) para valorar la velocidad aeróbica
máxima (VAM) y otros parámetros de resistencia aeróbica (umbral anaeróbico interválico y capacidad de
recuperación en el TVREF). La VAM mejoró 0.5 km/h en el TVREF (p<0.05), pero no en el Course
Navette (0.1 km/h y p>0.05), a pesar de que el nivel de esfuerzo (frecuencia cardiaca máxima) fue similar
en ambos tests. La velocidad en el umbral anaeróbico mejoró más que la VAM (0.9 km/h y p<0.001) en
el TVREF. La frecuencia cardiaca para la misma velocidad de carrera disminuyó en ambos tests, pero de
forma más significativa en el TVREF, lo que repercutió en una mejora de los porcentajes de recuperación
cardiaca en los estadíos previos al umbral anaeróbico. En conclusión, el test TVREF es más sensible que
el Course Navette para valorar los efectos del entrenamiento en fútbol, y ofrece más información que este
último (umbral anaeróbico y capacidad de recuperación). Futuros trabajos deben comprobar si se puede
estimar el VO2máx de los futbolistas al realizar este tes
ECMO in pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension as a bridge-to-therapy
Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries
Abstract
Background
Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres.
Methods
This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries.
Results
In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia.
Conclusion
This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries