Quantum Phase Transitions and Heat Capacity in a two-atoms Bose-Hubbard Model

We show that a two-atoms Bose-Hubbard model exhibits three different phases in the behavior of thermal entanglement in its parameter space. These phases are demonstrated to be traceable back to the existence of quantum phase transitions in the same system. Significant similarities between the behaviors of thermal entanglement and heat capacity in the parameter space are brought to light thus allowing to interpret the occurrence and the meaning of all these three phases.Comment: 6 pages, 3 figure

Heat Capacity and Entanglement Measure in a simple two-qubit model

A simple two-qubit model showing Quantum Phase Transitions as a consequence of ground state level crossings is studied in detail. Using the Concurrence of the system as an entanglement measure and heat capacity as a marker of thermodynamical properties, an analytical expression giving the latter in terms of the former is obtained. A protocol allowing an experimental measure of entanglement is then presented and compared with a related proposal recently reported by Wie\'sniak, Vedral and BruknerComment: 7 pages, 3 figure

Entropy production and information fluctuations along quantum trajectories

Employing the stochastic wave function method, we study quantum features of stochastic entropy production in nonequilibrium processes of open systems. It is demonstarted that continuous measurements on the environment introduce an additional, non-thermal contribution to the entropy flux, which is shown to be a direct consequence of quantum fluctuations. These features lead to a quantum definition of single trajectory entropy contributions, which accounts for the difference between classical and quantum trajectories and results in a quantum correction to the standard form of the integral fluctuation theorem.Comment: 9 pages, 5 figure

Tomographic approach to the violation of Bell's inequalities for quantum states of two qutrits

The tomographic method is employed to investigate the presence of quantum correlations in two classes of parameter-dependent states of two qutrits. The violation of some Bell's inequalities in a wide domain of the parameter space is shown. A comparison between the tomographic approach and a recent method elaborated by Wu, Poulsen and Molmer shows the better adequacy of the former method with respect to the latter one.Comment: 9 pages, 4 figure

Effects of oral, smoked, and vaporized cannabis on endocrine pathways related to appetite and metabolism: a randomized, double-blind, placebo-controlled, human laboratory study.

As perspectives on cannabis continue to shift, understanding the physiological and behavioral effects of cannabis use is of paramount importance. Previous data suggest that cannabis use influences food intake, appetite, and metabolism, yet human research in this regard remains scant. The present study investigated the effects of cannabis administration, via different routes, on peripheral concentrations of appetitive and metabolic hormones in a sample of cannabis users. This was a randomized, crossover, double-blind, placebo-controlled study. Twenty participants underwent four experimental sessions during which oral cannabis, smoked cannabis, vaporized cannabis, or placebo was administered. Active compounds contained 6.9 ± 0.95% (~50.6 mg) ∆9-tetrahydrocannabinol (THC). Repeated blood samples were obtained, and the following endocrine markers were measured: total ghrelin, acyl-ghrelin, leptin, glucagon-like peptide-1 (GLP-1), and insulin. Results showed a significant drug main effect (p = 0.001), as well as a significant drug × time-point interaction effect (p = 0.01) on insulin. The spike in blood insulin concentrations observed under the placebo condition (probably due to the intake of brownie) was blunted by cannabis administration. A significant drug main effect (p = 0.001), as well as a trend-level drug × time-point interaction effect (p = 0.08) was also detected for GLP-1, suggesting that GLP-1 concentrations were lower under cannabis, compared to the placebo condition. Finally, a significant drug main effect (p = 0.01) was found for total ghrelin, suggesting that total ghrelin concentrations during the oral cannabis session were higher than the smoked and vaporized cannabis sessions. In conclusion, cannabis administration in this study modulated blood concentrations of some appetitive and metabolic hormones, chiefly insulin, in cannabis users. Understanding the mechanisms underpinning these effects may provide additional information on the cross-talk between cannabinoids and physiological pathways related to appetite and metabolism

The Effects of Naltrexone Among Alcohol Non-Abstainers: Results from the COMBINE Study

These analyses of the COMBINE Study examined the effects of naltrexone among non-abstainers. Given that one of the most well-established mechanisms of action of naltrexone involves blunting of alcohol reward, it is hypothesized that naltrexone should be more effective among individuals who drank during treatment. Participants were 952 (78% of the total COMBINE Study sample) treatment-seeking alcohol-dependent men and women who received pharmacotherapy for alcoholism and drank at least once during the 16-week trial. Mixed model analyses revealed that individuals who drank more regularly during the trial seemed to benefit most from naltrexone and the effects of naltrexone on heavy drinking was significant in treatment months 2 through 4 among individuals who reported drinking on 81, 68, and 60% or more of days, respectively. Those drinking frequencies were observed in 11, 15, and 19% of the sample. Similar effects were not observed for drinks per drinking day. These results suggest that a small subgroup of non-abstainers, composed primarily of very regular drinkers, appears to benefit from naltrexone in reducing heavy drinking days. Naltrexone may be effective in the context of controlled-drinking approaches, even among very frequent drinkers

Identification of dysregulated microRNA networks in schwann cell-like cultures exposed to immune challenge: Potential crosstalk with the protective VIP/PACAP neuropeptide system

© 2018 by the authors. Licensee MDPI, Basel, Switzerland. Following peripheral nerve injury, dysregulations of certain non-coding microRNAs (miRNAs) occur in Schwann cells. Whether these alterations are the result of local inflammation and/or correlate with perturbations in the expression profile of the protective vasoactive intestinal peptide (VIP)/pituitary adenylate cyclase-activating polypeptide (PACAP) system is currently unknown. To address these issues, we aimed at profiling the expression of selected miRNAs in the rat RT4 Schwann cell line. Cells exposed to lipopolysaccharide (LPS), to mimic the local inflammatory milieu, were appraised by real-time qPCR, Western blot and ELISAs. We found that upon LPS treatment, levels of pro-inflammatory cytokines (IL-1β, -6, -18, -17A, MCP-1 and TNFα) increased in a time-dependent manner. Unexpectedly, the expression levels of VIP and PACAP were also increased. Conversely, levels of VPAC1 and VPAC2 receptors were reduced. Downregulated miRNAs included miR-181b, -145, -27a, -340 and -132 whereas upregulated ones were miR-21, -206, -146a, -34a, -155, -204 and -29a, respectively. Regression analyses revealed that a subset of the identified miRNAs inversely correlated with the expression of VPAC1 and VPAC2 receptors. In conclusion, these findings identified a novel subset of miRNAs that are dysregulated by immune challenge whose activities might elicit a regulatory function on the VIP/PACAP system

Tackling dipeptidyl peptidase IV in neurological disorders

© 2018, Medknow Publications. All rights reserved. Dipeptidyl peptidase IV (DPP-IV) is a serine protease best known for its role in inactivating glucagon-like peptide-1 (GLP-1), pituitary adenylate cyclase-activating polypeptide (PACAP) and glucose-dependent insulinotropic peptide (GIP), three stimulators of pancreatic insulin secretion with beneficial effects on glucose disposal. Owing to the relationship between DPP-IV and these peptides, inhibition of DPP-IV enzyme activity is considered as an attractive treatment option for diabetic patients. Nonetheless, increasing studies support the idea that DPP-IV might also be involved in the development of neurological disorders with a neuroinflammatory component, potentially through its non-incretin activities on immune cells. In this review article, we aim at highlighting recent literature describing the therapeutic value of DPP-IV inhibitors for the treatment of such neurological conditions. Finally, we will illustrate some of the promising results obtained using berberine, a plant extract with potent inhibitory activity on DPP-IV

Solid-Phase Synthesis and In-Silico Analysis of Iron-Binding Catecholato Chelators

Siderophores are iron-complexing compounds synthesized by bacteria and fungi. They are low molecular weight compounds (500-1500 Daltons) possessing high affinity for iron(III). Since 1970 a large number of siderophores have been characterized, the majority using hydroxamate or catecholate as functional groups. The biosynthesis of siderophores is typically regulated by the iron levels of the environment where the organism is located. Because of their exclusive affinity and specificity for iron(III), natural siderophores and their synthetic derivatives have been exploited in the treatment of human iron-overload diseases, as both diagnostic and therapeutic agents. Here, solid-phase approach for the preparation of hexadentate, peptide-based tricatecholato containing peptides is described. The versatility of the synthetic method allows for the design of a common scaffolding structure whereby diverse ligands can be conjugated. With so many possibilities, a computational approach has been developed which will facilitate the identification of those peptides which are capable of providing a high affinity iron(III) binding site. This study reports an integrated computational/synthetic approach towards a rational development of peptide-based siderophores