1,103 research outputs found
Considerations about the incompleteness of the Ehrenfest's theorem in quantum mechanics
We describe a study motivated by our interest to examine the incompleteness
of the Ehrenfest's theorem in quantum mechanics and to resolve a doubt
regarding whether or not the hermiticity of the hamiltonian operator is
sufficient to justify a simplification of the expression of the
macroscopic-observable time derivative that promotes the one usually found in
quantum-mechanics textbooks. The study develops by considering the simple
quantum system "particle in one-dimensional box". We propose theoretical
arguments to support the incompleteness of the Ehrenfest's theorem in the
formulation he gave, in agreement with similar findings already published by a
few authors, and corroborate them with the numerical example of an electric
charge in an electrostatic field.Comment: 28 pages, 5 figures, 1 table. To be submitted to European Journal of
Physics (https://iopscience.iop.org/journal/0143-0807
Edge and cluster computing as enabling infrastructure for Internet of Medical Things
(c) 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.The continuous adoption of fitness and medical smart sensors are boosting the development of Internet of Medical Things (IoMT), reshaping and revolutionizing Healthcare. This digital transformation is paving the way to new forms of care based on real-time analysis of huge amounts of data produced by sensors, which is seen as a basis for improving clinical efficiency and helping to save lives. A medical sensor typically produces several KBs of data per second so the collection and analysis of these data can be approached with Big Data technologies. The aim of this paper is to present and evaluate a hybrid architecture for real-time anomaly detection from data streams coming from sensors attached to patients. The architecture includes an edge computing data staging platform based on Raspberry Pi 3 for data logging, data transformation in RDF triple and data streaming towards a cluster computing running Apache Kafka for collecting RDFStreams, Apache Flink for running a parallel version of the Hierarchical Temporal Memory algorithm and Cassandra for data storing. The different layers of the architecture have been evaluated in terms of both CPU performance and memory usage using the REALDISP dataset.Peer ReviewedPostprint (author's final draft
Mathematical aspects relative to the fluid statics of a self-gravitating perfect-gas isothermal sphere
In the present paper we analyze and discuss some mathematical aspects of the
fluid-static configurations of a self-gravitating perfect gas enclosed in a
spherical solid shell. The mathematical model we consider is based on the
well-known Lane-Emden equation, albeit under boundary conditions that differ
from those usually assumed in the astrophysical literature. The existence of
multiple solutions requires particular attention in devising appropriate
numerical schemes apt to deal with and catch the solution multiplicity as
efficiently and accurately as possible. In sequence, we describe some
analytical properties of the model, the two algorithms used to obtain numerical
solutions, and the numerical results for two selected cases.Comment: Revision accepted for publication in "Communications in Computational
Physics"; 23 pages, 9 figure
The PTK7 and ROR2 Protein Receptors Interact in the Vertebrate WNT/Planar Cell Polarity (PCP) Pathway *
International audienceBackground: The planar cell polarity pathway plays important roles in morphogenetic processes. Results: PTK7 and ROR2 form a heterodimeric complex and bind to WNT5A, promoting JNK phosphorylation and regulating expression of paraxial protocadherin. Conclusion: PTK7 and ROR2 promote cell movement in mammalian cells and coordinate cell polarity during morphogenetic movements. Significance: We reveal new mechanisms of action of PTK7 in WNT/PCP signaling. The non-canonical WNT/planar cell polarity (WNT/PCP) pathway plays important roles in morphogenetic processes in vertebrates. Among WNT/PCP components, protein tyrosine kinase 7 (PTK7) is a tyrosine kinase receptor with poorly defined functions lacking catalytic activity. Here we show that PTK7 associates with receptor tyrosine kinase-like orphan receptor 2 (ROR2) to form a heterodimeric complex in mammalian cells. We demonstrate that PTK7 and ROR2 physically and functionally interact with the non-canonical WNT5A ligand, leading to JNK activation and cell movements. In the Xenopus embryo, Ptk7 functionally interacts with Ror2 to regulate protocadherin papc expression and morphogenesis. Furthermore , we show that Ptk7 is required for papc activation induced by Wnt5a. Interestingly, we find that Wnt5a stimulates the release of the tagged Ptk7 intracellular domain, which can translocate into the nucleus and activate papc expression. This study reveals novel molecular mechanisms of action of PTK7 in non-canonical WNT/PCP signaling that may promote cell and tissue movements
Molecular Sensing by Nanoporous Crystalline Polymers
Chemical sensors are generally based on the integration of suitable sensitive layers and transducing mechanisms. Although inorganic porous materials can be effective, there is significant interest in the use of polymeric materials because of their easy fabrication process, lower costs and mechanical flexibility. However, porous polymeric absorbents are generally amorphous and hence present poor molecular selectivity and undesired changes of mechanical properties as a consequence of large analyte uptake. In this contribution the structure, properties and some possible applications of sensing polymeric films based on nanoporous crystalline phases, which exhibit all identical nanopores, will be reviewed. The main advantages of crystalline nanoporous polymeric materials with respect to their amorphous counterparts are, besides a higher selectivity, the ability to maintain their physical state as well as geometry, even after large guest uptake (up to 10–15 wt%), and the possibility to control guest diffusivity by controlling the orientation of the host polymeric crystalline phase. The final section of the review also describes the ability of suitable polymeric films to act as chirality sensors, i.e., to sense and memorize the presence of non-racemic volatile organic compounds
erythema multiforme like rash in a patient sensitive to ofloxacin
and increase matrix metalloproteinases-1 of dermal 10. Farrell AM. Acquired perforating dermatosis in renal and broblasts in three-dimensional cultures. J Dermatol Sci diabetic patients. Lancet 1997; 349: 895–896. 2000; 24: 99–104. 11. Golub LM, Ramamurthy NS, McNamara TF, Greenwald 9. Ryan ME, Usman A, Ramamurthy NS, Golub LM, RA, Rifkin BR. Tetracyclines inhibit connective tissue Greenwald RA. Excessive matrix metalloproteinase activbreakdown: new therapeutic implications for an old family ity in diabetes: inhibition by tetracycline analogues with of drugs. Crit Rev Oral Biol Med 1991; 2: 297–321. zinc reactivity. Curr Med Chem 2001; 8: 305–316
Assessment of DNA damages in lymphocytes of agricultural workers exposed to pesticides by comet assay in a cross-sectional study
Purpose: To assess the predictive power of the comet assay in the context of occupational exposure to pesticides.
Materials and methods: The recruited subjects completed a structured questionnaire and gave a blood sample. Exposure to pesticides was measured by means of an algorithm based on Dosemeci’s work (Agricultural Health Study). Approximately 50 images were analyzed for each sample via fluores- cence microscopy. The extent of DNA damage was estimated by tail moment (TM) and is the product of tail DNA (%) and tail Length.
Results: Crude significant risks (odds ratios, ORs) for values higher than the 75th percentile of TM were observed among the exposed subjects (score>1). The frequency of some confounding factors (sex, age and smoking) was significantly higher among the exposed workers. A significant dose–effect relationship was observed between TM and exposure score. Significant high-risk estimates (ORs), adjusted by the studied confounding factors, among exposure to pesticides and TM, % tail DNA and tail length were confirmed using unconditional logistic regression models.
Conclusions: The adjusted associations (ORs) between the comet parameters and exposure to pesti- cides were significant. The sensitivity of the comet test was low (41%), the specificity (89%) and the predictive positive value (0.77) were found acceptable
Dietary essential amino acids for the treatment of heart failure with reduced ejection fraction
Aims: Heart failure with reduced ejection fraction (HFrEF) is a leading cause of mortality worldwide, requiring novel therapeutic and lifestyle interventions. Metabolic alterations and energy production deficit are hallmarks and thereby promising therapeutic targets for this complex clinical syndrome. We aim to study the molecular mechanisms and effects on cardiac function in rodents with HFrEF of a designer diet in which free essential amino acids - in specifically designed percentages - substituted for protein. Methods and results: Wild-type mice were subjected to transverse aortic constriction (TAC) to induce left ventricle (LV) pressure overload or sham surgery. Whole body glucose homeostasis was studied with glucose tolerance test, while myocardial dysfunction and fibrosis were measured with echocardiogram and histological analysis. Mitochondrial bioenergetics and morphology were investigated with oxygen consumption rate measurement and electron microscopy evaluation. Circulating and cardiac non-targeted metabolite profiles were analyzed by ultrahigh performance liquid chromatography-tandem mass spectroscopy, while RNA sequencing was used to identify signalling pathways mainly affected. The amino acid-substituted diet shows remarkable preventive and therapeutic effects. This dietary approach corrects the whole-body glucose metabolism and restores the unbalanced metabolic substrate usage - by improving mitochondrial fuel oxidation - in the failing heart. In particular, biochemical, molecular, and genetic approaches suggest that renormalization of branched-chain amino acid oxidation in cardiac tissue, which is suppressed in HFrEF, plays a relevant role. Beyond the changes of systemic metabolism, cell-autonomous processes may explain at least in part the diet's cardioprotective impact. Conclusion: Collectively, these results suggest that manipulation of dietary amino acids, and especially essential amino acids, is a potential adjuvant therapeutic strategy to treat systolic dysfunction and HFrEF in humans
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