359 research outputs found
On EPR paradox, Bell's inequalities and experiments which prove nothing
This article shows that the there is no paradox. Violation of Bell's
inequalities should not be identified with a proof of non locality in quantum
mechanics. A number of past experiments is reviewed, and it is concluded that
the experimental results should be re-evaluated. The results of the experiments
with atomic cascade are shown not to contradict the local realism. The article
points out flaws in the experiments with down-converted photons. The
experiments with neutron interferometer on measuring the "contextuality" and
Bell-like inequalities are analyzed, and it is shown that the experimental
results can be explained without such notions. Alternative experiment is
proposed to prove the validity of local realism.Comment: 27 pages, 8 figures. I edited a little the text and abstract I
corrected equations (49) and (50
Quantification of pulmonary perfusion using LSIM-CT correlates with pulmonary hemodynamics in patients with CTEPD
BackgroundLung subtraction iodine mapping (LSIM)-CT is a clinically useful technique that can visualize pulmonary mal-perfusion in patients with chronic thromboembolic pulmonary disease (CTEPD). However, little is known about the associations of LSIM images with hemodynamic parameters of patients with CTEPD. This study investigates a parameter of LSIM images associated with mean pulmonary arterial pressure (mPAP) and validates the association between pulmonary vascular resistance, right atrial pressure, cardiac index, and exercise capacity in patients with CTEPD.MethodsThis single-center, prospective, observational study involved 30 patients diagnosed with CTEPD using lung perfusion scintigraphy. To examine the correlation of decreased pulmonary perfusion area (DPA) with mPAP, areas with 0â10, 0â15, 0â20, and 0â30â
HU in lung subtraction images were adopted in statistical analysis. The DPA to total lung volume ratio (DPA ratio, %) was calculated as the ratio of each DPA volume to the total lung volume. To assess the correlation between DPA ratios of 0â10, 0â15, 0â20, and 0â30â
HU and mPAP, Spearman's rank correlation coefficient was used.ResultsThe DPA ratio of 0â10â
HU had the most preferable correlation with mPAP than DPA ratios of 0â15, 0â20, and 0â30â
HU (Ďâ=â0.440, Pâ=â0.015). The DPA ratio of 0â10â
HU significantly correlates with pulmonary vascular resistance (Ďâ=â0.445, Pâ=â0.015). The receiver operating characteristic curve analysis indicated that the best cutoff value of the DPA ratio of 0â10â
HU for the prediction of an mPAP of âĽ30â
mmHg was 8.5% (AUC, 0.773; 95% CI, 0.572â0.974; sensitivity, 83.3%; specificity, 75.0%). Multivariate linear regression analysis, which was adjusted for the main pulmonary arterial to ascending aortic diameter ratio and right ventricular to left ventricular diameter ratio, indicated that the DPA ratio of 0â10â
HU was independently and significantly associated with mPAP (Bâ=â89.7; 95% CI, 46.3â133.1, Pâ<â0.001).ConclusionThe DPA ratio calculated using LSIM-CT is possibly useful for estimating the hemodynamic status in patients with CTEPD
Gravitational Waves from Gravitational Collapse
Gravitational wave emission from the gravitational collapse of massive stars
has been studied for more than three decades. Current state of the art
numerical investigations of collapse include those that use progenitors with
realistic angular momentum profiles, properly treat microphysics issues,
account for general relativity, and examine non--axisymmetric effects in three
dimensions. Such simulations predict that gravitational waves from various
phenomena associated with gravitational collapse could be detectable with
advanced ground--based and future space--based interferometric observatories.Comment: 68 pages including 13 figures; revised version accepted for
publication in Living Reviews in Relativity (http://www.livingreviews.org
A taste sensor device for unmasking admixing of rancid or winey-vinegary olive oil to extra virgin olive oil
Electrochemical sensor devices have gathered great attention in food analysis namely for olive oil evaluation. The adulteration of extra-virgin olive oil with lower-grade olive oil is a common worldwide fraudulent practice, which detection is a challenging task. The potentiometric fingerprints recorded by lipid polymeric sensor membranes of an electronic tongue, together with linear discriminant analysis and simulated annealing meta-heuristic algorithm, enabled the detection of extra-virgin olive oil adulterated with olive oil for which an intense sensory defect could be perceived, specifically rancid or winey-vinegary negative sensations. The homemade designed taste device allowed the identification of admixing of extra-virgin olive oil with more than 2.5% or 5% of rancid or winey-vinegary olive oil, respectively. Predictive mean sensitivities of 84Âą4% or 92Âą4% and specificities of 79Âą6% or 93Âą3% were obtained for rancid or winey-vinegary adulterations, respectively, regarding an internal-validation procedure based on a repeated K-fold cross-validation variant (4 foldsĂ10 repeats, ensuring that the dataset was forty times randomly split into 4 folds, leaving 25% of the data for validation purposes). This performance was satisfactory since, according to the legal physicochemical and sensory analysis, the intentionally adulterated olive oil with percentages of 2.510%, could still be commercialized as virgin olive oil. It could also be concluded that at a 5% significance level, the trained panelists could not distinguish extra-virgin olive oil samples from those adulterated with 2.5% of rancid olive oil or up to 5% of winey-vinegary olive oil. Thus, the electronic tongue proposed in this study can be foreseen as a practical and powerful tool to detect this kind of worldwide common fraudulent practice of high quality olive oil.This work was ďŹnancially supported by Project POCI-01â0145FEDER-006984 â Associate Laboratory LSRE-LCM, Project UID/QUI/ 00616/2013 â CQ-VR, Project UID/BIO/04469/2013 â CEB and strategic project PEst-OE/AGR/UI0690/2014 â CIMO all funded by FEDER - Fundo Europeu de Desenvolvimento Regional through COMPETE2020 - Programa Operacional Competitividade e Internacionalização (POCI) â and by national funds through FCT - Fundação para a CiĂŞncia e a Tecnologia, Portugal. Nuno Rodrigues thanks FCT, POPH-QREN and FSE for the Ph.D. Grant (SFRH/BD/104038/2014). Souheib Oueslati is also grateful for the support of the Tunisian Ministry of Agriculture.info:eu-repo/semantics/publishedVersio
Cdk5 Is Required for Memory Function and Hippocampal Plasticity via the cAMP Signaling Pathway
Memory formation is modulated by pre- and post-synaptic signaling events in neurons. The neuronal protein kinase Cyclin-Dependent Kinase 5 (Cdk5) phosphorylates a variety of synaptic substrates and is implicated in memory formation. It has also been shown to play a role in homeostatic regulation of synaptic plasticity in cultured neurons. Surprisingly, we found that Cdk5 loss of function in hippocampal circuits results in severe impairments in memory formation and retrieval. Moreover, Cdk5 loss of function in the hippocampus disrupts cAMP signaling due to an aberrant increase in phosphodiesterase (PDE) proteins. Dysregulation of cAMP is associated with defective CREB phosphorylation and disrupted composition of synaptic proteins in Cdk5-deficient mice. Rolipram, a PDE4 inhibitor that prevents cAMP depletion, restores synaptic plasticity and memory formation in Cdk5-deficient mice. Collectively, our results demonstrate a critical role for Cdk5 in the regulation of cAMP-mediated hippocampal functions essential for synaptic plasticity and memory formation.Norman B. Leventhal FellowshipUnited States. National Institutes of Health (NIH T32 MH074249)United States. National Institutes of Health (NIH RO1 NS051874
Chitosan Modification and Pharmaceutical/Biomedical Applications
Chitosan has received much attention as a functional biopolymer for diverse applications, especially in pharmaceutics and medicine. Our recent efforts focused on the chemical and biological modification of chitosan in order to increase its solubility in aqueous solutions and absorbability in the in vivo system, thus for a better use of chitosan. This review summarizes chitosan modification and its pharmaceutical/biomedical applications based on our achievements as well as the domestic and overseas developments: (1) enzymatic preparation of low molecular weight chitosans/chitooligosaccharides with their hypocholesterolemic and immuno-modulating effects; (2) the effects of chitin, chitosan and their derivatives on blood hemostasis; and (3) synthesis of a non-toxic ion ligandâD-Glucosaminic acid from Oxidation of D-Glucosamine for cancer and diabetes therapy
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