96 research outputs found
Coboundary Lie bialgebras and commutative subalgebras of universal enveloping algebras
We solve a functional version of the problem of twist quantization of a
coboundary Lie bialgebra (g,r,Z). We derive from this the following results:
(a) the formal Poisson manifolds g^* and G^* are isomorphic; (b) we construct a
subalgebra of U(g^*), isomorphic to S(g^*)^g. When g can be quantized, we
construct a deformation of the morphism S(g^*)^g subset U(g^*). When g is
quasitriangular and nondegenerate, we compare our construction with
Semenov-Tian-Shansky's construction of a commutative subalgebra of U(g^*). We
also show that the canonical derivation of the function ring of G^* is
Hamiltonian
Formality theorems for Hochschild chains in the Lie algebroid setting
In this paper we prove Lie algebroid versions of Tsygan's formality
conjecture for Hochschild chains both in the smooth and holomorphic settings.
In the holomorphic setting our result implies a version of Tsygan's formality
conjecture for Hochschild chains of the structure sheaf of any complex manifold
and in the smooth setting this result allows us to describe quantum traces for
an arbitrary Poisson Lie algebroid. The proofs are based on the use of
Kontsevich's quasi-isomorphism for Hochschild cochains of R[[y_1,...,y_d]],
Shoikhet's quasi-isomorphism for Hochschild chains of R[[y_1,...,y_d]], and
Fedosov's resolutions of the natural analogues of Hochschild (co)chain
complexes associated with a Lie algebroid.Comment: 40 pages, no figure
Differential Regulation of the Period Genes in Striatal Regions following Cocaine Exposure
Several studies have suggested that disruptions in circadian rhythms contribute to the pathophysiology of multiple psychiatric diseases, including drug addiction. In fact, a number of the genes involved in the regulation of circadian rhythms are also involved in modulating the reward value for drugs of abuse, like cocaine. Thus, we wanted to determine the effects of chronic cocaine on the expression of several circadian genes in the Nucleus Accumbens (NAc) and Caudate Putamen (CP), regions of the brain known to be involved in the behavioral responses to drugs of abuse. Moreover, we wanted to explore the mechanism by which these genes are regulated following cocaine exposure. Here we find that after repeated cocaine exposure, expression of the Period (Per) genes and Neuronal PAS Domain Protein 2 (Npas2) are elevated, in a somewhat regionally selective fashion. Moreover, NPAS2 (but not CLOCK (Circadian Locomotor Output Cycles Kaput)) protein binding at Per gene promoters was enhanced following cocaine treatment. Mice lacking a functional Npas2 gene failed to exhibit any induction of Per gene expression after cocaine, suggesting that NPAS2 is necessary for this cocaine-induced regulation. Examination of Per gene and Npas2 expression over twenty-four hours identified changes in diurnal rhythmicity of these genes following chronic cocaine, which were regionally specific. Taken together, these studies point to selective disruptions in Per gene rhythmicity in striatial regions following chronic cocaine treatment, which are mediated primarily by NPAS2. © 2013 Falcon et al
Deletion of the GABAA α2-subunit does not alter self dministration of cocaine or reinstatement of cocaine seeking
Rationale
GABAA receptors containing α2-subunits are highly represented in brain areas that are involved in motivation and reward, and have been associated with addiction to several drugs, including cocaine. We have shown previously that a deletion of the α2-subunit results in an absence of sensitisation to cocaine.
Objective
We investigated the reinforcing properties of cocaine in GABAA α2-subunit knockout (KO) mice using an intravenous self-administration procedure.
Methods
α2-subunit wildtype (WT), heterozygous (HT) and KO mice were trained to lever press for a 30 % condensed milk solution. After implantation with a jugular catheter, mice were trained to lever press for cocaine (0.5 mg/kg/infusion) during ten daily sessions. Responding was extinguished and the mice tested for cue- and cocaine-primed reinstatement. Separate groups of mice were trained to respond for decreasing doses of cocaine (0.25, 0.125, 0.06 and 0.03 mg/kg).
Results
No differences were found in acquisition of lever pressing for milk. All genotypes acquired self-administration of cocaine and did not differ in rates of self-administration, dose dependency or reinstatement. However, whilst WT and HT mice showed a dose-dependent increase in lever pressing during the cue presentation, KO mice did not.
Conclusions
Despite a reported absence of sensitisation, motivation to obtain cocaine remains unchanged in KO and HT mice. Reinstatement of cocaine seeking by cocaine and cocaine-paired cues is also unaffected. We postulate that whilst not directly involved in reward perception, the α2-subunit may be involved in modulating the “energising” aspect of cocaine’s effects on reward-seeking
Capacitance free generation and detection of subpicosecond electrical pulses on coplanar transmission lines
Based on a reanalysis of previous work and new experimental measurements, we conclude that the parasitic capacitance at the generation site is negligible for sliding contact excitation of small dimension coplanar transmission lines.Peer reviewedElectrical and Computer Engineerin
Barriers and solutions for global access to osteoporosis management: a position paper from the international osteoporosis foundation
Our ability to optimally manage bone health across the lifecourse, and so minimise the risk of fractures, has advanced substantially in recent decades. Whilst fractures and osteoporosis in older age were historically viewed simply as inherent in normal ageing, they are now recognised as manifestations of age-related disease. Key to advancing the field was the development of conceptual (relating to impaired bone mass and microarchitecture with increased propensity to fracture), and subsequent World Health Organization densitometric definitions of osteoporosis, cementing the role of dual-energy X-ray absorptiometry in bone health management. However, whilst low bone mineral density is a strong risk factor for fracture, many individuals who do fracture have normal or only modestly reduced bone mineral density. Furthermore, the existence of two definitions constituting a condition called “osteoporosis”, one based on a measurement, and the other conceptual, has led to uncertainty in clinical practice. The field is therefore moving towards calculation of an individual’s absolute fracture risk, based on clinical risk factors, with the option to incorporate bone mineral density (if available) as a risk factor rather than as an indication for treatment. Uptake of this new direction has been variable internationally, with many parts of the world, particularly low- and middle-income countries, still predicating treatment (where osteoporosis services exist) on bone mineral density, despite poor availability of densitometry in many such settings. In this Position Paper, on behalf of the International Osteoporosis Foundation, we review the current barriers which prevent equitable access to optimal bone health management worldwide and recommend potential solutions which might be implemented to overcome them
Effects of vitamin D3, omega-3s, and a simple home exercise program on incident vertebral fractures: the DO-HEALTH randomized controlled trial
Vertebral fractures (VFs) are among the most common osteoporotic fractures. The effect of vitamin D3, omega-3s or a simple home exercise program (SHEP) on VFs is unclear. We examined whether vitamin D3, omega-3s, or SHEP, alone or in combination, over 3 years, reduce the incidence rate of VFs among European older adults. DO-HEALTH is a multi-center, 2 × 2 × 2 factorial design, randomized controlled trial, which included older adults (≥70 years) free from major health events in the 5 years prior to enrollment. The study interventions were vitamin D3 (2000IU/d), omega-3s (1 g/d), and SHEP (3 × 30 min/wk), applied alone or in combination. Quantitative and qualitative VF assessment was determined from lateral thoracolumbar DXA scans. The primary outcome for this analysis was the incidence rate (IR) of total VFs, defined as the number of any new and progressed VFs over the 3-year follow-up. Sensitivity analyses were conducted for only new VFs and only VF progressions. Negative binomial regression models were fit, adjusted for age, sex, prior fall, BMI, study site and participants' follow-up time. 1488 participants (mean age 74.9 years; 77% had low bone mass or osteoporosis; 43.8% had 25(OH)D levels <20 ng/mL) were included. There were 93 incident VFs, of which 58 were new VFs and 35 were progressions. None of the three treatments reduced the IR of total VFs overall, however, the IR was reduced with SHEP compared to the control exercise program in women (IR ratio 0.52, 95% CI 0.28, 0.98). In the sensitivity analysis for VF progressions, SHEP reduced the IR (IR ratio 0.34, 95% CI 0.16, 0.75). Among generally healthy older adults, vitamin D3 and omega-3s supplementation did not reduce the incidence rate of VFs. SHEP reduced the incidence rate of total VFs in women and of VF progressions overall. Exercise may play a role in the prevention of VFs
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