1,465 research outputs found
Pre-hospital management, procedural performance and outcomes for primary percutaneous coronary intervention in st-elevation myocardial infarction in the netherlands: Insights from the dutch cohort of the apposition-III trial
Interrogating cortical function with transcranial magnetic stimulation: insights from neurodegenerative disease and stroke
Transcranial magnetic stimulation (TMS) is an accessible, non-invasive technique to study cortical function in vivo. TMS studies have provided important pathophysiological insights across a range of neurodegenerative disorders and enhanced our understanding of brain reorganisation after stroke. In neurodegenerative disease, TMS has provided novel insights into the function of cortical output cells and the related intracortical interneuronal networks. Characterisation of cortical hyperexcitability in amyotrophic lateral sclerosis and altered motor cortical function in frontotemporal dementia, demonstration of cholinergic deficits in Alzheimer's disease and Parkinson's disease are key examples where TMS has led to advances in understanding of disease pathophysiology and potential mechanisms of propagation, with the potential for diagnostic applications. In stroke, TMS methodology has facilitated the understanding of cortical reorganisation that underlie functional recovery. These insights are critical to the development of effective and targeted rehabilitation strategies in stroke. The present review will provide an overview of cortical function measures obtained using TMS and how such measures may provide insight into brain function. Through an improved understanding of cortical function across a range of neurodegenerative disorders, and identification of changes in neural structure and function associated with stroke that underlie clinical recovery, more targeted therapeutic approaches may now be developed in an evolving era of precision medicine
Nanoelectromechanical coupling in fullerene peapods probed via resonant electrical transport experiments
Fullerene peapods, that is carbon nanotubes encapsulating fullerene
molecules, can offer enhanced functionality with respect to empty nanotubes.
However, the present incomplete understanding of how a nanotube is affected by
entrapped fullerenes is an obstacle for peapods to reach their full potential
in nanoscale electronic applications. Here, we investigate the effect of C60
fullerenes on electron transport via peapod quantum dots. Compared to empty
nanotubes, we find an abnormal temperature dependence of Coulomb blockade
oscillations, indicating the presence of a nanoelectromechanical coupling
between electronic states of the nanotube and mechanical vibrations of the
fullerenes. This provides a method to detect the C60 presence and to probe the
interplay between electrical and mechanical excitations in peapods, which thus
emerge as a new class of nanoelectromechanical systems.Comment: 7 pages, 3 figures. Published in Nature Communications. Free online
access to the published version until Sept 30th, 2010, see
http://www.nature.com/ncomms/journal/v1/n4/abs/ncomms1034.htm
Mapping the optimal route between two quantum states
A central feature of quantum mechanics is that a measurement is intrinsically
probabilistic. As a result, continuously monitoring a quantum system will
randomly perturb its natural unitary evolution. The ability to control a
quantum system in the presence of these fluctuations is of increasing
importance in quantum information processing and finds application in fields
ranging from nuclear magnetic resonance to chemical synthesis. A detailed
understanding of this stochastic evolution is essential for the development of
optimized control methods. Here we reconstruct the individual quantum
trajectories of a superconducting circuit that evolves in competition between
continuous weak measurement and driven unitary evolution. By tracking
individual trajectories that evolve between an arbitrary choice of initial and
final states we can deduce the most probable path through quantum state space.
These pre- and post-selected quantum trajectories also reveal the optimal
detector signal in the form of a smooth time-continuous function that connects
the desired boundary conditions. Our investigation reveals the rich interplay
between measurement dynamics, typically associated with wave function collapse,
and unitary evolution of the quantum state as described by the Schrodinger
equation. These results and the underlying theory, based on a principle of
least action, reveal the optimal route from initial to final states, and may
enable new quantum control methods for state steering and information
processing.Comment: 12 pages, 9 figure
Experimental and theoretical investigation of ligand effects on the synthesis of ZnO nanoparticles
ZnO nanoparticles with highly controllable particle sizes(less than 10 nm) were synthesized using organic capping ligands in Zn(Ac)2 ethanolic solution. The molecular structure of the ligands was found to have significant influence on the particle size. The multi-functional molecule tris(hydroxymethyl)-aminomethane (THMA) favoured smaller particle distributions compared with ligands possessing long hydrocarbon chains that are more frequently employed. The adsorption of capping ligands on ZnnOn crystal nuclei (where n = 4 or 18 molecular clusters of(0001) ZnO surfaces) was modelled by ab initio methods at the density functional theory (DFT) level. For the molecules examined, chemisorption proceeded via the formation of Zn...O, Zn...N, or Zn...S chemical bonds between the ligands and active Zn2+ sites on ZnO surfaces. The DFT results indicated that THMA binds more strongly to the ZnO surface than other ligands, suggesting that this molecule is very effective at stabilizing ZnO nanoparticle surfaces. This study, therefore, provides new insight into the correlation between the molecular structure of capping ligands and the morphology of metal oxide nanostructures formed in their presence
Chronic ileocolic intussusception due to transmural infiltration of diffuse large B cell lymphoma in a 14-year-old boy: a case report
Human embryonic stem cell-derived neurons establish region-specific, long-range projections in the adult brain
While the availability of pluripotent stem cells has opened new prospects for generating neural donor cells for nervous system repair, their capability to integrate with adult brain tissue in a structurally relevant way is still largely unresolved. We addressed the potential of human embryonic stem cell-derived long-term self-renewing neuroepithelial stem cells (lt-NES cells) to establish axonal projections after transplantation into the adult rodent brain. Transgenic and species-specific markers were used to trace the innervation pattern established by transplants in the hippocampus and motor cortex. In vitro, lt-NES cells formed a complex axonal network within several weeks after the initiation of differentiation and expressed a composition of surface receptors known to be instrumental in axonal growth and pathfinding. In vivo, these donor cells adopted projection patterns closely mimicking endogenous projections in two different regions of the adult rodent brain. Hippocampal grafts placed in the dentate gyrus projected to both the ipsilateral and contralateral pyramidal cell layers, while axons of donor neurons placed in the motor cortex extended via the external and internal capsule into the cervical spinal cord and via the corpus callosum into the contralateral cortex. Interestingly, acquisition of these region-specific projection profiles was not correlated with the adoption of a regional phenotype. Upon reaching their destination, human axons established ultrastructural correlates of synaptic connections with host neurons. Together, these data indicate that neurons derived from human pluripotent stem cells are endowed with a remarkable potential to establish orthotopic long-range projections in the adult mammalian brain
A Systematic Review of Online Sex Addiction and Clinical Treatments Using CONSORT Evaluation
Researchers have suggested that the advances of the Internet over the past two decades have gradually eliminated traditional offline methods of obtaining sexual material. Additionally, research on cybersex and/or online sex addictions has increased alongside the development of online technology. The present study extended the findings from Griffiths’ (2012) systematic empirical review of online sex addiction by additionally investigating empirical studies that implemented and/or documented clinical treatments for online sex addiction in adults. A total of nine studies were identified and then each underwent a CONSORT evaluation. The main findings of the present review provide some evidence to suggest that some treatments (both psychological and/or pharmacological) provide positive outcomes among those experiencing difficulties with online sex addiction. Similar to Griffiths’ original review, this study recommends that further research is warranted to establish the efficacy of empirically driven treatments for online sex addiction
Macroalgal responses to ocean acidification depend on nutrient and light levels
Ocean acidification may benefit algae that are able to capitalize on increased carbon availability for photosynthesis, but it is expected to have adverse effects on calcified algae through dissolution. Shifts in dominance between primary producers will have knock-on effects on marine ecosystems and will likely vary regionally, depending on factors such as irradiance (light vs. shade) and nutrient levels (oligotrophic vs. eutrophic). Thus experiments are needed to evaluate interactive effects of combined stressors in the field. In this study, we investigated the physiological responses of macroalgae near a CO2 seep in oligotrophic waters off Vulcano (Italy). The algae were incubated in situ at 0.2 m depth using a combination of three mean CO2 levels (500, 700-800 and 1200 μatm CO2), two light levels (100 and 70% of surface irradiance) and two nutrient levels of N, P, and K (enriched vs. non-enriched treatments) in the non-calcified macroalga Cystoseira compressa (Phaeophyceae, Fucales) and calcified Padina pavonica (Phaeophyceae, Dictyotales). A suite of biochemical assays and in vivo chlorophyll a fluorescence parameters showed that elevated CO2 levels benefitted both of these algae, although their responses varied depending on light and nutrient availability. In C. compressa, elevated CO2 treatments resulted in higher carbon content and antioxidant activity in shaded conditions both with and without nutrient enrichment-they had more Chla, phenols and fucoxanthin with nutrient enrichment and higher quantum yield (Fv/Fm) and photosynthetic efficiency (αETR) without nutrient enrichment. In P. pavonica, elevated CO2 treatments had higher carbon content, Fv/Fm, αETR, and Chla regardless of nutrient levels-they had higher concentrations of phenolic compounds in nutrient enriched, fully-lit conditions and more antioxidants in shaded, nutrient enriched conditions. Nitrogen content increased significantly in fertilized treatments, confirming that these algae were nutrient limited in this oligotrophic part of the Mediterranean. Our findings strengthen evidence that brown algae can be expected to proliferate as the oceans acidify where physicochemical conditions, such as nutrient levels and light, permit
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