52 research outputs found
Magnetization and dimerization profiles of the cut two-leg spin ladder and spin-1 chain
The physical properties of the edge states of the cut two-leg spin ladder are
investigated by means of the bosonization approach. By carefully treating
boundary conditions, we derive the existence of spin-1/2 edge states in the
spin ladder with a ferromagnetic rung exchange and for the open spin-1
Heisenberg chain. In contrast, such states are absent in the antiferromagnetic
rung coupling case. The approach, based on a mapping onto decoupled
semi-infinite off-critical Ising models, allows us to compute several physical
quantities of interest. In particular, we determine the magnetization and
dimerization profiles of the cut two-leg spin ladder and of the open
biquadratic spin-1 chain in the vicinity of the SU(2) WZNW critical point.Comment: RevTeX 4, no figure, 26 page
Aligning the CMS Muon Chambers with the Muon Alignment System during an Extended Cosmic Ray Run
Peer reviewe
New insights into the genetic etiology of Alzheimer's disease and related dementias
Characterization of the genetic landscape of Alzheimer's disease (AD) and related dementias (ADD) provides a unique opportunity for a better understanding of the associated pathophysiological processes. We performed a two-stage genome-wide association study totaling 111,326 clinically diagnosed/'proxy' AD cases and 677,663 controls. We found 75 risk loci, of which 42 were new at the time of analysis. Pathway enrichment analyses confirmed the involvement of amyloid/tau pathways and highlighted microglia implication. Gene prioritization in the new loci identified 31 genes that were suggestive of new genetically associated processes, including the tumor necrosis factor alpha pathway through the linear ubiquitin chain assembly complex. We also built a new genetic risk score associated with the risk of future AD/dementia or progression from mild cognitive impairment to AD/dementia. The improvement in prediction led to a 1.6- to 1.9-fold increase in AD risk from the lowest to the highest decile, in addition to effects of age and the APOE ε4 allele
Synthesis, Stereochemistry, and Biological Activity of the 1-(1-Phenyl-2-methylcyclohexyl)piperidines and the 1-(1-Phenyl-4-methylcyclohexyl)piperidines. Absolute Configuration of the Potent trans-(-)-1-(1-Phenyl-2-methylcyclohexyl)piperidine.
The (-)- and (+)-isomers of the cis- and trans-Ph/Me 1-(1-Phenyl-2-methylcyclohexyl)piperidines have been sinthesized and the achiral cis- and trans-Ph/Me 1-(1-Phenyl-4-methylcyclohexyl)piperidines were prepared, and their in vitro and in vivo activities determined
Sliding Mode Model Semantics and Simulation for Hybrid Systems
We describe model semantics and develop a simulation algorithm for characterizing a class of dynamic physical systems operating in the so-called sliding regimes. Complex continuous system behavior combines effects that occur at multiple temporal and spatial scales. Behavior generation is simplified by creating system models that employ time scale and parameter abstraction techniques. The resultant hybrid systems possess discrete and continuous behaviors, which manifest as piecewise continuous behaviors interspersed with discontinuous changes between the continuous operating modes. Mode transitions are induced by internal state changes and external control signals. Sometimes hybrid systems exhibit chattering behaviors at the discontinuous transition boundaries. This presents computational challenges to conventional numerical simulation methods. We develop an efficient, adaptive algorithm for simulating this class of systems, based on a careful analysis of the model semantics at the discontinuous boundaries. Simulation results show that the algorithm is more efficient and accurate than conventional integration methods for sliding-mode systems
GSK‐3 inhibition by adenoviral FRAT1 overexpression is neuroprotective and induces Tau dephosphorylation and β‐catenin stabilisation without elevation of glycogen synthase activity
Glycogen synthase kinase 3 (GSK-3) has previously
been shown to play an important role in the regulation of
apoptosis. However, the nature of GSK-3 effector pathways that
are relevant to neuroprotection remains poorly defined. Here, we
have compared neuroprotection resulting from modulation of
GSK-3 activity in PC12 cells using either selective small
molecule ATP-competitive GSK-3 inhibitors (SB-216763 and
SB-415286), or adenovirus overexpressing frequently rearranged
in advanced T-cell lymphomas 1 (FRAT1), a protein proposed as
a negative regulator of GSK-3 activity towards Axin and
Glycogen synthase kinase 3 (GSK-3) has previously
been shown to play an important role in the regulation of
apoptosis. However, the nature of GSK-3 effector pathways that
are relevant to neuroprotection remains poorly defined. Here, we
have compared neuroprotection resulting from modulation of
GSK-3 activity in PC12 cells using either selective small
molecule ATP-competitive GSK-3 inhibitors (SB-216763 and
SB-415286), or adenovirus overexpressing frequently rearranged
in advanced T-cell lymphomas 1 (FRAT1), a protein proposed as
a negative regulator of GSK-3 activity towards Axin and
β-catenin. Our data demonstrate that cellular overexpression
of FRAT1 is sufficient to confer neuroprotection and correlates
with inhibition of GSK-3 activity towards Tau and β-catenin,
but not modulation of glycogen synthase (GS) activity. By
comparison, treatment with SB-216763 and SB-415286 proved
more potent in terms of neuroprotection, and correlated with
inhibition of GSK-3 activity towards GS in addition to Tau and
β-catenin-catenin. Our data demonstrate that cellular overexpression
of FRAT1 is sufficient to confer neuroprotection and correlates
with inhibition of GSK-3 activity towards Tau and β-catenin,
but not modulation of glycogen synthase (GS) activity. By
comparison, treatment with SB-216763 and SB-415286 proved
more potent in terms of neuroprotection, and correlated with
inhibition of GSK-3 activity towards GS in addition to Tau and
β-cateni
Response of quaking aspen genotypes to enriched CO2: foliar chemistry and tussock moth performance
1 Genetic variation in the phytochemical responses of plants to CO2 enrichment is likely to alter trophic dynamics, and to shift intraspecific selection pressures on plant populations. We evaluated the independent and interactive effects of atmospheric CO2 and quaking aspen (Populus tremuloides Michx.) genotype on chemical composition of foliage and performance of the whitemarked tussock moth (Orgyia leucostigma J. E. Sm.)
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