133 research outputs found
Cortical Surface Area and Cortical Thickness Demonstrate Differential Structural Asymmetry in Auditory-Related Areas of the Human Cortex
This investigation provides an analysis of structural asymmetries in 5 anatomically defined regions (Heschl's gyrus, HG; Heschl's sulcus, HS; planum temporale, PT; planum polare, PP; superior temporal gyrus, STG) within the human auditory-related cortex. Volumetric 3-dimensional T1-weighted magnetic resonance imaging scans were collected from 104 participants (52 males). Cortical volume (CV), cortical thickness (CT), and cortical surface area (CSA) were calculated based on individual scans of these anatomical traits. This investigation demonstrates a leftward asymmetry for CV and CSA that is observed in the HG, STG, and PT regions. As regards CT, we note a rightward asymmetry in the HG and HS. A correlation analysis of asymmetry indices between measurements for distinct regions of interest (ROIs) yields significant correlations between CT and CV in 4 of 5 ROIs (HG, HS, PT, and STG). Significant correlation values between CSA and CV are observed for all 5 ROIs. The findings suggest that auditory-related cortical areas demonstrate larger leftward asymmetry with respect to the CSA, while a clear rightward asymmetry with respect to CT is salient in both the primary and the secondary auditory cortex only. In addition, we propose that CV is not an ideal neuromarker for anatomical measurements. CT and CSA should be considered independent traits of anatomical asymmetries in the auditory-related corte
Tuning the mobility of a driven Bose-Einstein condensate via diabatic Floquet bands
We study the response of ultracold atoms to a weak force in the presence of a
temporally strongly modulated optical lattice potential. It is experimentally
demonstrated that the strong ac-driving allows for a tailoring of the mobility
of a dilute atomic Bose-Einstein condensate with the atoms moving ballistically
either along or against the direction of the applied force. Our results are in
agreement with a theoretical analysis of the Floquet spectrum of a model
system, thus revealing the existence of diabatic Floquet bands in the atom's
band spectra and highlighting their role in the non-equilibrium transport of
the atoms
Quantum creep and quantum creep transitions in 1D sine-Gordan chains
Discrete sine-Gordon (SG) chains are studied with path-integral molecular
dynamics. Chains commensurate with the substrate show the transition from
collective quantum creep to pinning at bead masses slightly larger than those
predicted from the continuous SG model. Within the creep regime, a field-driven
transition from creep to complete depinning is identified. The effects of
disorder in the external potential on the chain's dynamics depend on the
potential's roughness exponent , i.e., quantum and classical fluctuations
affect the current self-correlation functions differently for .Comment: 4 pages, 3 figure
Targeting High Mobility Group Box 1 in Subarachnoid Hemorrhage: A Systematic Review
Aneurysmal subarachnoid hemorrhage (aSAH) is a complex and potentially deadly disease. Neurosurgical clipping or endovascular coiling can successfully obliterate ruptured aneurysms in almost every case. However, despite successful interventions, the clinical outcomes of aSAH patients are often poor. The reasons for poor outcomes are numerous, including cerebral vasospasm (CVS), post-hemorrhagic hydrocephalus, systemic infections and delayed cerebral ischemia. Although CVS with subsequent cerebral ischemia is one of the main contributors to brain damage after aSAH, little is known about the underlying molecular mechanisms of brain damage. This review emphasizes the importance of pharmacological interventions targeting high mobility group box 1 (HMGB1)-mediated brain damage after subarachnoid hemorrhage (SAH) and CVS. We searched Pubmed, Ovid medline and Scopus for “subarachnoid hemorrhage” in combination with “HMGB1”. Based on these criteria, a total of 31 articles were retrieved. After excluding duplicates and selecting the relevant references from the retrieved articles, eight publications were selected for the review of the pharmacological interventions targeting HMGB1 in SAH. Damaged central nervous system cells release damage-associated molecular pattern molecules (DAMPs) that are important for initiating, driving and sustaining the inflammatory response following an aSAH. The discussed evidence suggested that HMGB1, an important DAMP, contributes to brain damage during early brain injury and also to the development of CVS during the late phase. Different pharmacological interventions employing natural compounds with HMGB1-antagonizing activity, antibody targeting of HMGB1 or scavenging HMGB1 by soluble receptors for advanced glycation end products (sRAGE), have been shown to dampen the inflammation mediated brain damage and protect against CVS. The experimental data suggest that HMGB1 inhibition is a promising strategy to reduce aSAH-related brain damage and CVS. Clinical studies are needed to validate these findings that may lead to the development of potential treatment options that are much needed in aSAH
Targeting High Mobility Group Box 1 in Subarachnoid Hemorrhage: A Systematic Review
Aneurysmal subarachnoid hemorrhage (aSAH) is a complex and potentially deadly disease. Neurosurgical clipping or endovascular coiling can successfully obliterate ruptured aneurysms in almost every case. However, despite successful interventions, the clinical outcomes of aSAH patients are often poor. The reasons for poor outcomes are numerous, including cerebral vasospasm (CVS), post-hemorrhagic hydrocephalus, systemic infections and delayed cerebral ischemia. Although CVS with subsequent cerebral ischemia is one of the main contributors to brain damage after aSAH, little is known about the underlying molecular mechanisms of brain damage. This review emphasizes the importance of pharmacological interventions targeting high mobility group box 1 (HMGB1)-mediated brain damage after subarachnoid hemorrhage (SAH) and CVS. We searched Pubmed, Ovid medline and Scopus for “subarachnoid hemorrhage” in combination with “HMGB1”. Based on these criteria, a total of 31 articles were retrieved. After excluding duplicates and selecting the relevant references from the retrieved articles, eight publications were selected for the review of the pharmacological interventions targeting HMGB1 in SAH. Damaged central nervous system cells release damage-associated molecular pattern molecules (DAMPs) that are important for initiating, driving and sustaining the inflammatory response following an aSAH. The discussed evidence suggested that HMGB1, an important DAMP, contributes to brain damage during early brain injury and also to the development of CVS during the late phase. Different pharmacological interventions employing natural compounds with HMGB1-antagonizing activity, antibody targeting of HMGB1 or scavenging HMGB1 by soluble receptors for advanced glycation end products (sRAGE), have been shown to dampen the inflammation mediated brain damage and protect against CVS. The experimental data suggest that HMGB1 inhibition is a promising strategy to reduce aSAH-related brain damage and CVS. Clinical studies are needed to validate these findings that may lead to the development of potential treatment options that are much needed in aSAH
Stochastic kinetics of viral capsid assembly based on detailed protein structures
We present a generic computational framework for the simulation of viral
capsid assembly which is quantitative and specific. Starting from PDB files
containing atomic coordinates, the algorithm builds a coarse grained
description of protein oligomers based on graph rigidity. These reduced protein
descriptions are used in an extended Gillespie algorithm to investigate the
stochastic kinetics of the assembly process. The association rates are obtained
from a diffusive Smoluchowski equation for rapid coagulation, modified to
account for water shielding and protein structure. The dissociation rates are
derived by interpreting the splitting of oligomers as a process of graph
partitioning akin to the escape from a multidimensional well. This modular
framework is quantitative yet computationally tractable, with a small number of
physically motivated parameters. The methodology is illustrated using two
different viruses which are shown to follow quantitatively different assembly
pathways. We also show how in this model the quasi-stationary kinetics of
assembly can be described as a Markovian cascading process in which only a few
intermediates and a small proportion of pathways are present. The observed
pathways and intermediates can be related a posteriori to structural and
energetic properties of the capsid oligomers
Developmental dyscalculia: a dysconnection syndrome?
Numerical understanding is important for everyday life. For children with developmental dyscalculia (DD), numbers and magnitudes present profound problems which are thought to be based upon neuronal impairments of key regions for numerical understanding. The aim of the present study was to investigate possible differences in white matter fibre integrity between children with DD and controls using diffusion tensor imaging. White matter integrity and behavioural measures were evaluated in 15 children with developmental dyscalculia aged around 10years and 15 matched controls. The main finding, obtained by a whole brain group comparison, revealed reduced fractional anisotropy in the superior longitudinal fasciculus in children with developmental dyscalculia. In addition, a region of interest analysis exhibited prominent deficits in fibres of the superior longitudinal fasciculus adjacent to the intraparietal sulcus, which is thought to be the core region for number processing. To conclude, our results outline deficient fibre projection between parietal, temporal and frontal regions in children with developmental dyscalculia, and therefore raise the question of whether dyscalculia can be seen as a dysconnection syndrome. Since the superior longitudinal fasciculus is involved in the integration and control of distributed brain processes, the present results highlight the importance of considering broader domain-general mechanisms in the diagnosis and therapy of dyscalculia
Gliding dislocations in a driven vortex lattice
The dynamics of dislocations in a two-dimensional vortex lattice is studied
in the presence of a pinning potential and a transport current. In a vortex
lattice drifting with velocity a glide velocity of the dislocation
with respect to the vortex lattice is found to decay like for
large drive. From this result the velocity for the crossover between a regime
of coherent elastic motion and a regime of incoherent plastic motion of
vortices is estimated.Comment: 4 pages Revte
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