Topology conserving gauge action and the overlap-Dirac operator

We apply the topology conserving gauge action proposed by Luescher to the four-dimensional lattice QCD simulation in the quenched approximation. With this gauge action the topological charge is stabilized along the hybrid Monte Carlo updates compared to the standard Wilson gauge action. The quark potential and renormalized coupling constant are in good agreement with the results obtained with the Wilson gauge action. We also investigate the low-lying eigenvalue distribution of the hermitian Wilson-Dirac operator, which is relevant for the construction of the overlap-Dirac operator.Comment: 27pages, 11figures, accepted versio

Simulation of Transitions between "Pasta" Phases in Dense Matter

Calculations of equilibrium properties of dense matter predict that at subnuclear densities nuclei can be rodlike or slablike. To investigate whether transitions between phases with non-spherical nuclei can occur during the collapse of a star, we perform quantum molecular dynamic simulations of the compression of dense matter. We have succeeded in simulating the transitions between rodlike and slablike nuclei and between slablike nuclei and cylindrical bubbles. Our results strongly suggest that non-spherical nuclei can be formed in the inner cores of collapsing stars.Comment: 4 pages, 4 figures, final version published in Phys. Rev. Lett., high-res figures can be seen at http://www.nordita.dk/~gentaro/research/fig

Associations between purine metabolites and clinical symptoms in schizophrenia

Background: The antioxidant defense system, which is known to be dysregulated in schizophrenia, is closely linked to the dynamics of purine pathway. Thus, alterations in the homeostatic balance in the purine pathway may be involved in the pathophysiology of schizophrenia. Methodology/Principal Findings: Breakdown products in purine pathway were measured using high-pressure liquid chromatography coupled with a coulometric multi-electrode array system for 25 first-episode neuroleptic-naïve patients with schizophrenia at baseline and at 4-weeks following initiation of treatment with antipsychotic medication. Associations between these metabolites and clinical and neurological symptoms were examined at both time points. The ratio of uric acid and guanine measured at baseline predicted clinical improvement following four weeks of treatment with antipsychotic medication. Baseline levels of purine metabolites also predicted clinical and neurological symtpoms recorded at baseline; level of guanosine was associated with degree of clinical thought disturbance, and the ratio of xanthosine to guanosine at baseline predicted degree of impairment in the repetition and sequencing of actions. Conclusions/Significance: Findings suggest an association between optimal levels of purine byproducts and dynamics in clinical symptoms and adjustment, as well as in the integrity of sensory and motor processing. Taken together, alterations in purine catabolism may have clinical relevance in schizophrenia pathology

Fluvoxamine for aripiprazole-associated akathisia in patients with schizophrenia: a potential role of sigma-1 receptors

<p>Abstract</p> <p>Background</p> <p>Second-generation antipsychotic drugs have been reported to cause fewer incidences of extrapyramidal side effects (EPSs) than typical antipsychotic drugs, but adverse events such as akathisia have been observed even with atypical antipsychotic drugs. Although understanding of the pathophysiology of akathisia remains limited, it seems that a complex interplay of several neurotransmitter systems might play a role in its pathophysiology. The endoplasmic reticulum protein sigma-1 receptors are shown to regulate a number of neurotransmitter systems in the brain.</p> <p>Methods</p> <p>We report on two cases in which monotherapy of the selective serotonin reuptake inhibitor and sigma-1 receptor agonist fluvoxamine was effective in ameliorating the akathisia of patients with schizophrenia treated with the antipsychotic drug aripiprazole.</p> <p>Results</p> <p>The global score on the Barnes Akathisia Scale in the two patients with schizophrenia treated with aripiprazole decreased after fluvoxamine monotherapy.</p> <p>Conclusion</p> <p>Doctors may wish to consider fluvoxamine as an alternative approach in treating akathisia associated with antipsychotic drugs such as aripiprazole.</p

Pharmacological Characterization of [3H]CHIBA-3007 Binding to Glycine Transporter 1 in the Rat Brain

Glycine transporter-1 (GlyT-1) in glial cells regulates extracellular levels of glycine, which acts as an obligatory co-agonist at the N-methyl-D-aspartate (NMDA) receptors in the brain. In the present study, we developed a novel radioligand, [3H]3-chloro-N-((S)-((R)-1-methylpiperidin-2-yl)(thiophen- 3-yl)methyl)-4- (trifluoromethyl)picolinamide ([3H]CHIBA-3007), for studying GlyT-1 in the brain. The presence of a single saturable high-affinity binding component for [3H]CHIBA-3007 binding to the rat brain membranes was detected. Scatchard analysis revealed an apparent equilibrium dissociation constant (Kd) of 1.61±0.16 nM and a maximal number of binding sites (Bmax) of 692.8±22.8 fmol/mg protein (mean ± SEM, n = 3). The specific binding of [3H]CHIBA-3007 was inhibited by a number of GlyT-1 inhibitors, such as CHIBA-3007, desmethyl-CHIBA-3007, CHIBA-3008, SSR504734, NFPS/ALX5407, LY2365109 and Org24598, consistent with the pharmacological profiles of GlyT-1 inhibitors. Interestingly, the potency of eight GlyT-1 inhibitors (CHIBA-3007, desmethyl-CHIBA-3007, NFPS/ALX5407, LY2365109, Org24598, SSR504734, sarcosine, and glycine) for blocking in vitro specific binding of [3H]CHIBA-3007 was significantly correlated with the potency of these inhibitors for inhibiting [14C]glycine uptake in the rat brain membranes. In contrast, the GlyT-2 inhibitor ALX1393 exhibited very weak for [3H]CHIBA-3007 binding. Furthermore, the regional distribution of [3H]CHIBA-3007 binding in the rat brain was similar to the previously reported distribution of GlyT-1. The present findings suggest that [3H]CHIBA-3007 would be a useful new radioligand for studying GlyT-1 in the brain

Kondo model for the "0.7 anomaly" in transport through a quantum point contact

Experiments on quantum point contacts have highlighted an anomalous conductance plateau at $0.7 (2e^2/h)$, with features suggestive of the Kondo effect. Here we present an Anderson model for transport through a point contact which we analyze in the Kondo limit. Hybridization to the band increases abruptly with energy but decreases with valence, so that the background conductance and the Kondo temperature $T_K$ are dominated by different valence transitions. This accounts for the high residual conductance above $T_K$. A spin-polarized current is predicted for Zeeman splitting $g^* \mu_B B > k_B T_K,k_BT$.Comment: 4 page

Sigma-1 receptor agonist fluvoxamine for postoperative delirium in older adults: report of three cases

<p>Abstract</p> <p>Background</p> <p>Postoperative delirium is a topic of great importance in the geriatric surgical specialty. Although antipsychotic drugs are the medications most frequently used to treat this syndrome, these drugs are associated with a variety of adverse events, including sedation, extrapyramidal side effects, and cardiac arrhythmias. Drug treatment for postoperative delirium requires careful consideration of the balance between the effective management of symptoms and potential adverse effects.</p> <p>Methods</p> <p>We report on a Japanese woman (an 86-year-old (open reduction and internal fixation of the right femoral neck fracture), and two Japanese men (an 86-year-old (abdominal aortic aneurysm stent grafting), and a 77-year-old (right upper lobectomy due to lung tumour)) in which the selective serotonin reuptake inhibitor and sigma-1 receptor agonist fluvoxamine was effective in ameliorating the postoperative delirium of these patients.</p> <p>Results</p> <p>Delirium Rating Scale scores in these patients dramatically decreased after treatment with fluvoxamine.</p> <p>Conclusions</p> <p>Doctors should consider fluvoxamine as an alternative approach to treating postoperative delirium in older patients in order to avoid the risk of side effects and increased mortality by antipsychotic drugs.</p

Microscopic Study of Slablike and Rodlike Nuclei: Quantum Molecular Dynamics Approach

Structure of cold dense matter at subnuclear densities is investigated by quantum molecular dynamics (QMD) simulations. We succeeded in showing that the phases with slab-like and rod-like nuclei etc. can be formed dynamically from hot uniform nuclear matter without any assumptions on nuclear shape. We also observe intermediate phases, which has complicated nuclear shapes. Geometrical structures of matter are analyzed with Minkowski functionals, and it is found out that intermediate phases can be characterized as ones with negative Euler characteristic. Our result suggests the existence of these kinds of phases in addition to the simple ``pasta'' phases in neutron star crusts.Comment: 6 pages, 4 figures, RevTex4; to be published in Phys. Rev. C Rapid Communication (accepted version