Exact relaxation in a class of nonequilibrium quantum lattice systems

A reasonable physical intuition in the study of interacting quantum systems says that, independent of the initial state, the system will tend to equilibrate. In this work we introduce an experimentally accessible setting where relaxation to a steady state is exact, namely, for the Bose-Hubbard model quenched from a Mott quantum phase to the free strong superfluid regime. We rigorously prove that the evolving state locally relaxes to a steady state with maximum entropy constrained by second moments--thus maximizing the entanglement. Remarkably, for this to be true, no time average is necessary. Our argument includes a central limit theorem and exploits the finite speed of information transfer. We also show that for all periodic initial configurations (charge density waves) the system relaxes locally, and identify experimentally accessible signatures in optical lattices as well as implications for the foundations of statistical mechanics.

Statistics dependence of the entanglement entropy

The entanglement entropy of a distinguished region of a quantum many-body system reflects the entanglement in its pure ground state. Here we establish scaling laws for this entanglement in critical quasifree fermionic and bosonic lattice systems, without resorting to numerical means. We consider the setting of D-dimensional half-spaces which allows us to exploit a connection to the one-dimensional case. Intriguingly, we find a difference in the scaling properties depending on whether the system is bosonic-where an area law is proven to hold-or fermionic where we determine a logarithmic correction to the area law, which depends on the topology of the Fermi surface. We find Lifshitz quantum phase transitions accompanied with a nonanalyticity in the prefactor of the leading order term.

[Health-related quality of life in dermatologists compared to other physicians]

BACKGROUND

According to recent studies, there may be differences in quality of life for physicians depending on gender and field of medicine. Presently, there are hardly any data with respect to health-related quality of life in dermatologists.

METHODS

Using the SF-36 Health Survey, 112 dermatologists and 113 physicians in other fields of medicine were studied in a cross-sectional study.

RESULTS

Dermatologists' mental health level averaged lower than their physical health level (chi2=28.49; p<.001). The mental and physical health level were higher in female dermatologists than in their male colleagues (e.g., GH: chi2=6.15; p<.05 and MH: chi2=6.83; p<.05). These findings are the opposite of results in other medical specialists. The differences between mental and physical health dimensions on the one hand, and between women and men on the other hand, were found in all age groups.

CONCLUSIONS

In comparison to other medical specialists, dermatologists differ only slightly in their health-related quality of life. Therefore, it may be advisable to implement preventive measures concerning their comparatively low mental health status.

Biphenyl-indanones: allosteric potentiators of the metabotropic glutamate subtype 2 receptor

We have identified and synthesized a series of biphenyl-carboxylic acid indanones as allosteric potentiators of the metabotropic glutamate receptor 2. Structure-activity relationship studies directed toward improving the potency and the brain to plasma ratio of the initial lead led to the discovery of 5 and 23 (EC50=111 and 5 nM, respectively).

3-[Substituted]-5-(5-pyridin-2-yl-2H-tetrazol-2-yl)benzonitriles: Identification of highly potent and selective metabotropic glutamate subtype 5 receptor antagonists

Structure-activity relationship studies on the phenyl ring of 3-(5-pyridin-2-yl-2H-tetrazol-2-yl)benzonitrile 2 led to the discovery that small, non-hydrogen bond donor substituents at the 3-position led to a substantial increase in in vitro potency. In particular, 3-fluoro-5-(5-pyridin-2-yl-2H-tetrazol-2-yl)benzonitrile (7) is a highly potent and selective mGlu5 receptor antagonist with good rat pharmacokinetics, brain penetration, and in vivo receptor occupancy.

Water soluble prodrug of a COX-2 selective inhibitor suitable for intravenous administration in models of cerebral ischemia

A water soluble choline prodrug (17) of a COX-2 selective inhibitor (16) suitable for intravenous dosing in models of cerebral ischemia has been developed. Constant infusion studies using 17 demonstrate that extrapolated brain levels of 16 may be maintained for over 24h in rats.

Cyclohexenyl- and dehydropiperidinyl-alkynyl pyridines as potent metabotropic glutamate subtype 5 (mGlu5) receptor antagonists

Structure-activity relationship studies leading to the discovery of novel mGlu5 receptor antagonists are described. These compounds show high in vitro potency, have good in vivo receptor occupancy, and a reasonable intravenous pharmacokinetic profile.

In vitro metabolic studies on the selective metabotropic glutamate receptor sub-type 5 (mGluR5) antagonist 3-[(2-methyl-1,3-thiazol-4-yl) ethynyl]-pyridine (MTEP)

Metabotropic glutamate receptors (mGluR) are G-protein-coupled receptors that play a major role in modulatory pathways in the CNS and have been suggested to have pharmacological implications in pain, psychiatric disorders and other neurological states. 3-[(2-Methyl-1,3-thiazol-4-yl) ethynyl]-pyridine (MTEP) is a specific and selective antagonist for the mGluR sub-type 5. Previous studies using rat liver microsomes showed that the major oxidative metabolites of MTEP are a hydroxymethyl metabolite (M1), two oxides (M2 and M4), a thiazole-ring opened metabolite (M3) and CO(2) (M5). In the present study, we examined the metabolism of MTEP in liver microsomes and expressed rat and human CYP isoforms. In rat liver microsomes, metabolic stability studies accurately predicted the in vivo clearance for MTEP. Incubation of MTEP with expressed rat and human CYP isoforms showed that CYP1A and CYP2C isoforms are primarily responsible for the metabolism of this compound. The results suggest that species differences in MTEP metabolism is possible and could contribute to specie-differences in biological effects of the compound.

Influence of acid surrogates toward potency of VLA-4 antagonist

A series of VLA-4 antagonist were synthesized wherein carboxylic acid was replaced by various acid surrogates. The effect of these acid surrogates toward potency was evaluated in a binding assay. A number of acid surrogates were potent antagonist of VLA-4, albeit significantly less potent than the corresponding carboxylic acid. Heterocyclic acid surrogate, oxadiazolidinone 3, demonstrated an improved pharmacokinetic property when dosed intravenously.

METABOLISM AND DISPOSITION OF A POTENT GROUP II METABOTROPIC GLUTAMATE RECEPTOR AGONIST, IN RATS, DOGS, AND MONKEYS

Metabolism and disposition of MGS0028 [(1R,2S,5S,6S)-2-amino-6-fluoro-4-oxobicyclo[3.1.0]hexane-2,6-dicarboxylic acid monohydrate], a potent group II metabotropic glutamate receptor agonist, were examined in three preclinical species (Sprague-Dawley rats, beagle dogs, and rhesus monkeys). In rats, MGS0028 was widely distributed and primarily excreted in urine as parent and as a single reductive metabolite, identified as the 4R-isomer MGS0034 [(1R,2S,4R,5S,6S)-2-amino-6-fluoro-4-hydroxybicyclo[3.1.0]-hexane-2,6-dicarboxylic acid]. MGS0028 had a low brain to plasma ratio at efficacious doses in rats and was eliminated more slowly in rat brain than in plasma. Exposure increased proportionally (1--10 mg/kg p.o.) in rats, with bioavailability>60% at all doses. However, bioavailability was only approximately 20% in monkeys, and MGS0034 was found in relatively high abundance in plasma. In dogs, oral bioavailability was >60%, and the metabolite was not detected. In vitro metabolism was examined in liver subcellular fractions (microsomes and cytosol) from rat, dog, monkey, and human. Reductive metabolism was observed in rat, monkey, and human liver cytosol incubations, but not in dog liver cytosol incubations. No metabolism of MGS0028 was detected in incubations with liver microsomes from any species. Similar to in vivo results, MGS0028 was reduced in cytosol stereospecifically to MGS0034. The rank order of in vitro metabolite formation (monkey >> rat approximately human >> dog) was in agreement with in vivo observations in rats, dogs, and monkeys. Based on the observation of species difference in reductive metabolism, rat and monkey were recommended to be the preclinical species for further characterization prior to testing in humans. Finally, allometric scaling predicts that human pharmacokinetic parameters would be acceptable for further development.

5-[(2-Methyl-1,3-thiazol-4-yl)ethynyl]-2,3'-bipyridine: a highly potent, orally active metabotropic glutamate subtype 5 (mGlu5) receptor antagonist with anxiolytic activity

Structure-activity relationship studies leading to the discovery of a new, orally active mGlu5 receptor antagonist are described. The title compound, 5-[(2-methyl-1,3-thiazol-4-yl)ethynyl]-2,3'-bipyridine, is highly potent in vitro, has good in vivo receptor occupancy, and is efficacious in the rat fear-potentiated startle model of anxiety following oral dosing.

Entropy, entanglement, and area: analytical results for harmonic lattice systems

We revisit the question of the relation between entanglement, entropy, and area for harmonic lattice Hamiltonians corresponding to discrete versions of real free Klein-Gordon fields. For the ground state of the d-dimensional cubic harmonic lattice we establish a strict relationship between the surface area of a distinguished hypercube and the degree of entanglement between the hypercube and the rest of the lattice analytically, without resorting to numerical means. We outline extensions of these results to longer ranged interactions, finite temperatures, and for classical correlations in classical harmonic lattice systems. These findings further suggest that the tools of quantum information science may help in establishing results in quantum field theory that were previously less accessible.

Inhomogeneous atomic Bose-Fermi mixtures in cubic lattices

We determine the ground state properties of inhomogeneous mixtures of bosons and fermions in cubic lattices and parabolic confining potentials. For finite hopping we determine the domain boundaries between Mott-insulator plateaux and hopping-dominated regions for lattices of arbitrary dimension within mean-field and perturbation theory. The results are compared with a new numerical method that is based on a Gutzwiller variational approach for the bosons and an exact treatment for the fermions. The findings can be applied as a guideline for future experiments with trapped atomic Bose-Fermi mixtures in optical lattices.

3-[3-Fluoro-5-(5-pyridin-2-yl-2H-tetrazol-2-yl)phenyl]-4-methylpyridine: a highly potent and orally bioavailable metabotropic glutamate subtype 5 (mGlu5) receptor antagonist

Structure-activity relationship studies performed around 3-fluoro-5-(5-pyridin-2-yl-2H-tetrazol-2-yl)benzonitrile for the purpose of developing novel mGlu5 receptor antagonists are described. Synthesis of a series of four-ring tetrazoles led to the discovery of 3-[3-fluoro-5-(5-pyridin-2-yl-2H-tetrazol-2-yl)phenyl]-4-methylpyridine, a highly potent, brain penetrant, azole-based mGlu5 receptor antagonist.

2-{2-[3-(Pyridin-3-yloxy)phenyl]-2H-tetrazol-5-yl}pyridine: a highly potent, orally active, metabotropic glutamate subtype 5 (mGlu5) receptor antagonist

Structure-activity relationship studies on 3-(5-pyridin-2-yl-2H-tetrazol-2-yl)benzonitrile 2 led to the discovery of 2-(2-[3-(pyridin-3-yloxy)phenyl]-2H-tetrazol-5-yl)pyridine (10)-a highly potent and selective mGlu5 receptor antagonist with good brain penetration and in vivo receptor occupancy in rat and cross-species oral bioavailability.

Discovery of highly potent, selective, orally bioavailable, metabotropic glutamate subtype 5 (mGlu5) receptor antagonists devoid of cytochrome P450 1A2 inhibitory activity

Structure-activity relationship studies focused on bio-isosteric replacements of 2-pyridyl resulted in mGlu5 receptor antagonists with reduced inhibition of cytochrome P450 1A2. This led to highly potent, selective and orally bioavailable 2-imidazolyl tetrazoles such as (10) that are devoid of cytochrome P450 inhibitory activity.

Synthesis and biological evaluation of 6-aryl-6 H -pyrrolo[3,4- d ]pyridazine derivatives: high-affinity ligands to the α 2 δ subunit of voltage gated calcium channels

A novel class of 6-aryl-6H-pyrrolo[3,4-d]pyridazine ligands for the alpha2delta subunit of voltage-gated calcium channels has been described. Substitutions in the aryl ring of the molecule were generally not tolerated, and resulted in diminished binding to the alpha2delta subunit. Modifications to the pyridazine ring revealed numerous permissive substitutions, and detailed SAR studies were carried out in this portion of the molecule. Replacement of the pyridazine ring methyl group with an aminomethyl functionality provided greatly improved potency over the initial lead. The initial lead compound displayed good rat pharmacokinetic properties, and was shown to be efficacious in the Chung model for neuropathic pain in rats.

[Multislice CT of the pelvis: dose reduction with regard to image quality]

PURPOSE

To optimize the examination protocols of multislice CT (MSCT) of the pelvis for dose reduction with regard to image quality.

MATERIALS AND METHODS

MSCT of the pelvis was performed on 5 cadaver specimens with stepwise reduction of the tube current at 140 kV (250, 200, 150, 100, 75, 50, 35, 25 mAs) and 120 kV (50, 27 mAs). The remaining scan parameters like collimation (4 x 1 mm) and table speed of 4 mm per rotation remained unchanged. Axial sections and coronal reconstructions were used to evaluate cortex, trabecular structures, subjective image quality, image noise and detail detectability (pelvis and SI joint), with evaluation performed independently by four blinded experienced radiologists on a 5-point scale. Kappa coefficient, accuracy of the observers to sort the films with regard to dose reduction and mean scores of image evaluation were determined for statistical analysis.

RESULTS

The deterioration of the image quality was most pronounced for all criteria between 75 mAs and 50 mAs at 140 kV. Good results with adequate image quality were obtained for detail detectability at 50 mAs and 140 kV (effective dose [E]: 3.3 mSv) and for the remaining four criteria at 75 mAs (E: 4.9 mSv). There was a moderate agreement between the four observers (kappa coefficient: 0.27). All observers were excellent in arranging the images according to the increasing dose reduction.

CONCLUSIONS

Image quality of MSCT of the pelvis appears to be acceptable at 75 mAs and 140 kV with the dose reduced to 46% of the average value of the nation-wide survey of the German Roentgen Society in 1999 for this type of examination.

Prospective assessment of falls in Parkinson's disease

We studied prospectively the epidemiology, clinical impact and prediction of falls in 59 moderately affected patients with Parkinson's disease (PD) (mean UPDRS motor score 31.5; mean age 61 years) and 55 controls (mean age 60 years). At baseline, balance and gait were evaluated extensively. The retropulsion test (response to sudden shoulder pull) was executed first unexpectedly and five more times following prior warning. All persons used standardised scoring forms to document their falls during six months. Thirty patients (50.8 %) and eight controls (14.5%) fell at least once (relative risk [RR] 6.1; 95% confidence interval [CI] 2.5-15.1, p < 0.001). Recurrent (> or = 2) falls occurred in 15 patients (25.4%), but in only two controls (RR 9.0; 95 % CI 2.0-41.7; p=0.001). Recurrent falls were more common among persons taking benzodiazepines (RR 5.0; 95% CI 1.6-15.5; p < 0.01). Sixty-two percent of the falls in patients caused soft tissue injuries, but no fractures occurred. A fear of future falls was common (45.8 % of patients) and was accompanied by restriction of daily activities (44.1 % of patients). Seventy percent of falls reported by patients were'intrinsic' (due to patient-related factors), but falls in controls were mainly (50%) 'extrinsic' (due to environmental factors). None of the baseline posture and gait variables predicted falls adequately. The first 'unexpected' retropulsion test was more often abnormal than all subsequent (predictable) tests. Irrespective of its method of execution, the retropulsion test did not predict falls. A combination of asking for prior falls, disease severity and the Romberg test yielded the best overall diagnostic utility (sensitivity 65 % and specificity 98 %). Recurrent fallers were best predicted by disease severity (RR for Hoehn and Yahr stage 3 was > 100; 95% CI 3.1-585) and asking for prior falls (RR 5.0; 95% CI 1.2-20.9). We conclude that falls are common and disabling, even in relatively early stage PD. Recurrent fallers were best predicted by disease severity and presence of prior falls. Strategies to prevent falls in PD should particularly focus at intrinsic (patient-related) factors, such as minimising the use of benzodiazepines.

Perceived health needs of urban African American church congregants

Theory-based assessment of congregant expectations and needs should be conducted prior to beginning a parish nurse program. However, no such assessments are found in the literature. Using Andersen's Health Access Model as a framework, investigators conducted interviews with 117 randomly selected congregants in five urban African American churches to describe their perceived needs and expectations. Causing most concern were the following: (a) symptoms of illness--high blood pressure (50.4%), dental problems (43.6%), and back pain (41%); and (b) health habits/risks--weight (75%), exercise (63%), and diet (63%). Younger adults were significantly more concerned about all aspects of their health than their older counterparts. Women were significantly more likely to express concern about health habits and health risks than males. No significant relationship was found between perceived need and access to care. Although terming health care services "adequate", congregants expressed many unmet health needs. This seemingly contradictory finding may illuminate a concrete role for the parish nurse, i.e., addressing personal health care concerns not alleviated by the current "adequate" health care delivery system. This study's significance lies not only in providing programming guidance, but also in theoretical insights into the role of the parish nurse.