9 research outputs found

    Geometry Enhancement of Nanoscale Energy Deposition by X-rays

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    A theorem is established to show that nanoscale energy deposition in water by X-rays can be greatly enhanced via the geometry of nanostructures. The calculated results show that enhancement over background water can reach over 60 times for a single nanoshell made of gold. Other geometries and nanostructures are investigated, and it is found that a shell of gold nanoparticles can generate similar enhancement. The concepts of composition, matrix, and satellite effects are established and studied, all of which can further increase the enhancement of the effect of X-rays

    A sodium channel variant in Aedes aegypti as a candidate pathogen sensor for viral-associated molecular patterns.

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    Recent work demonstrated that a splice variant of a human macrophage voltage-gated sodium channel expressed on endosomes acts as an intracellular sensor for dsRNA, a viral-associated molecular pattern. Here our goal was to identify a candidate gene in a clinically relevant invertebrate model with related cellular and pattern recognition properties. The para gene in drosophila and other insects encodes voltage-gated sodium channels with similar electrophysiological properties to those found in vertebrate excitable membranes. A database search revealed that the AAEL006019 gene in Aedes aegypti, the yellow fever mosquito, encodes a voltage-gated sodium channel that is distinct from genes that encode para-like sodium channels. As compared to para-like channels, the protein products from this gene have deletions in the N-terminus and in the DII-DIII linker region. When over-expressed in an Aedes aegypti cell line, CCL-125, the AAEL006019 channel demonstrated cytoplasmic expression on vesicularlike organelles. Electrophysiologic analysis revealed that the channel mediates small inward currents that are enhanced by synthetic mimics of viral-derived ssRNA, R848 and ORN02, but not the dsRNA mimic, poly I:C. R848 treatment of CCL-125 cells that express high levels of the channels led to increased expression of RelA and Ago2, two mediators of insect innate immunity. These results suggest that the AAEL006019 channel acts as an intracellular pathogen sensor for ssRNA molecular patterns

    Nanoscale Dynamics versus Surface Interactions: What Dictates Osmotic Transport?

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    The classical paradigm for osmotic transport has long related the induced-flow direction to the solute membrane interactions, with the low-to-high concentration flow a direct consequence of the solute rejection from the semipermeable membrane. In principle, the same was thought to occur for the newly demonstrated membrane-free osmotic transport named diffusio-osmosis. Using a recently proposed nanofluidic setup, we revisit this cornerstone of osmotic transport by studying the diffusio-osmotic flows generated at silica surfaces by either poly­(ethylene)­glycol polymers or ethanol molecules in aqueous solutions. Strikingly, both neutral solutes yield osmotic flows in the usual low to high concentration direction, in contradiction with their propensity to adsorb on silica. Considering theoretically and numerically the intricate nature of the osmotic response that combines molecular-scale surface interaction and near-wall dynamics, these findings are rationalized within a generalized framework. These elements constitute a step forward toward a finer understanding of osmotically driven flows, at the core of rapidly growing fields ranging from energy harvesting to active matter

    Interregional correlations of glucose metabolism between the basal ganglia and different cortical areas: an ultra-high resolution PET/MRI fusion study using 18F-FDG

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    <div><p>Basal ganglia have complex functional connections with the cerebral cortex and are involved in motor control, executive functions of the forebrain, such as the planning of movement, and cognitive behaviors based on their connections. The aim of this study was to provide detailed functional correlation patterns between the basal ganglia and cerebral cortex by conducting an interregional correlation analysis of the 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) data based on precise structural information. Fifteen participants were scanned with 7-Tesla magnetic resonance imaging (MRI) and high resolution research tomography (HRRT)-PET fusion system using 18F-FDG. For detailed interregional correlation analysis, 24 subregions of the basal ganglia including pre-commissural dorsal caudate, post-commissural caudate, pre-commissural dorsal putamen, post-commissural putamen, internal globus pallidus, and external globus pallidus and 80 cerebral regions were selected as regions of interest on the MRI image and their glucose metabolism were calculated from the PET images. Pearson's product-moment correlation analysis was conducted for the interregional correlation analysis of the basal ganglia. Functional correlation patterns between the basal ganglia and cerebral cortex were not only consistent with the findings of previous studies, but also showed new functional correlation between the dorsal striatum (i.e., caudate nucleus and putamen) and insula. In this study, we established the detailed basal ganglia subregional functional correlation patterns using 18F-FDG PET/MRI fusion imaging. Our methods and results could potentially be an important resource for investigating basal ganglia dysfunction as well as for conducting functional studies in the context of movement and psychiatric disorders.</p></div

    Responsibility to Protect (R2P) in French Foreign Policy 2008 - 2013

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    This Master's thesis deals with the emerging international norm Responsibility to Protect (R2P) in French Foreign Policy between 2008 and 2013. Responsibility to Protect was created in 2001 by the International Commission on Intervention and State Sovereignty and endorsed by the UN World Summit in 2005. It has changed the understanding of state sovereignty in international relations by emphasizing the responsibility component of sovereignty. It gives priority to the security of individuals. France has been an active agenda-setter in the field of human protection norms in the 1980s and 1990s and it has showed a supportive approach towards R2P. The thesis examines whether the conceptualization of R2P in current French foreign policy is coherent with this tradition. The research is based on the concepts of ethical foreign policy and alternative national interest. The analysis of strategic documents setting the priorities of French foreign policy between 2008 and 2013 as well as an examination of the three military interventions based on R2P (Libya, Côte d'Ivoire and Central African Republic) in which France played an active role have shown that in the France's foreign policy is based on moral principles which it upholds in strategic documents. In practice ethical foreign policy also prevails over..

    In Situ Synthesis of Graphene/Polyselenophene Nanohybrid Materials as Highly Flexible Energy Storage Electrodes

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    A new class of graphene–polyselenophene (PSe) hybrid nanocomposite was successfully synthesized using an <i>in situ</i> synthetic method. The synthesized graphene–PSe nanocomposite exhibited unique properties including a large voltage window, high conductivity, and good mechanical properties. The graphene–PSe nanohybrid reduced the dynamic resistance of electrolyte ions and enabled high charge–discharge rates, thereby enabling high-performance supercapacitance. The results were attributed to synergetic effects between graphene and conducting polymers (CPs), which enhanced charge transport, surface area, and hybrid supercapacitance by combining the properties of electrolytic double-layer capacitors (EDLCs) with those of psedocapacitors. Additionally, a flexible supercapacitor based on the graphene–PSe nanohybrid was successfully demonstrated. To fabricate binder-free supercapacitors, chemical vapor deposition (CVD) and vapor deposition polymerization (VDP) methods were employed. The fabricated all-solid-state supercapacitor exhibited outstanding mechanical and electrochemical performance, even after several bending motions. The novel graphene–PSe nanocomposite material is promising for new energy storage and conversion applications

    Efficient Excitonic Photoluminescence in Direct and Indirect Band Gap Monolayer MoS<sub>2</sub>

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    We discuss the photoluminescence (PL) of semiconducting transition metal dichalcogenides on the basis of experiments and a microscopic theory. The latter connects ab initio calculations of the single-particle states and Coulomb matrix elements with a many-body description of optical emission spectra. For monolayer MoS<sub>2</sub>, we study the PL efficiency at the excitonic A and B transitions in terms of carrier populations in the band structure and provide a quantitative comparison to an (In)­GaAs quantum well-structure. Suppression and enhancement of PL under biaxial strain is quantified in terms of changes in the local extrema of the conduction and valence bands. The large exciton binding energy in MoS<sub>2</sub> enables two distinctly different excitation methods: above-band gap excitation and quasi-resonant excitation of excitonic resonances below the single-particle band gap. The latter case creates a nonequilibrium distribution of carriers predominantly in the K-valleys, which leads to strong emission from the A-exciton transition and a visible B-peak even if the band gap is indirect. For above-band gap excitation, we predict a strongly reduced emission intensity at comparable carrier densities and the absence of B-exciton emission. The results agree well with PL measurements performed on monolayer MoS<sub>2</sub> at excitation wavelengths of 405 nm (above) and 532 nm (below the band gap)

    Association Between Telomere Length and Risk of Cancer and Non-Neoplastic Diseases: A Mendelian Randomization Study

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    Importance: The causal direction and magnitude of the association between telomere length and incidence of cancer and non-neoplastic diseases is uncertain owing to the susceptibility of observational studies to confounding and reverse causation. Objective: To conduct a Mendelian randomization study, using germline genetic variants as instrumental variables, to appraise the causal relevance of telomere length for risk of cancer and non-neoplastic diseases. Data Sources: Genomewide association studies (GWAS) published up to January 15, 2015. Study Selection: GWAS of noncommunicable diseases that assayed germline genetic variation and did not select cohort or control participants on the basis of preexisting diseases. Of 163 GWAS of noncommunicable diseases identified, summary data from 103 were available. Data Extraction and Synthesis: Summary association statistics for single nucleotide polymorphisms (SNPs) that are strongly associated with telomere length in the general population. Main Outcomes and Measures: Odds ratios (ORs) and 95% confidence intervals (CIs) for disease per standard deviation (SD) higher telomere length due to germline genetic variation. Results: Summary data were available for 35 cancers and 48 non-neoplastic diseases, corresponding to 420 081 cases (median cases, 2526 per disease) and 1 093 105 controls (median, 6789 per disease). Increased telomere length due to germline genetic variation was generally associated with increased risk for site-specific cancers. The strongest associations (ORs [95% CIs] per 1-SD change in genetically increased telomere length) were observed for glioma, 5.27 (3.15-8.81); serous low-malignant-potential ovarian cancer, 4.35 (2.39-7.94); lung adenocarcinoma, 3.19 (2.40-4.22); neuroblastoma, 2.98 (1.92-4.62); bladder cancer, 2.19 (1.32-3.66); melanoma, 1.87 (1.55-2.26); testicular cancer, 1.76 (1.02-3.04); kidney cancer, 1.55 (1.08-2.23); and endometrial cancer, 1.31 (1.07-1.61). Associations were stronger for rarer cancers and at tissue sites with lower rates of stem cell division. There was generally little evidence of association between genetically increased telomere length and risk of psychiatric, autoimmune, inflammatory, diabetic, and other non-neoplastic diseases, except for coronary heart disease (OR, 0.78 [95% CI, 0.67-0.90]), abdominal aortic aneurysm (OR, 0.63 [95% CI, 0.49-0.81]), celiac disease (OR, 0.42 [95% CI, 0.28-0.61]) and interstitial lung disease (OR, 0.09 [95% CI, 0.05-0.15]). Conclusions and Relevance: It is likely that longer telomeres increase risk for several cancers but reduce risk for some non-neoplastic diseases, including cardiovascular diseases
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