Persistence of Covalent Bonding in Liquid Silicon Probed by Inelastic X-ray Scattering

Metallic liquid silicon at 1787K is investigated using x-ray Compton scattering. An excellent agreement is found between the measurements and the corresponding Car-Parrinello molecular dynamics simulations. Our results show persistence of covalent bonding in liquid silicon and provide support for the occurrence of theoretically predicted liquid-liquid phase transition in supercooled liquid states. The population of covalent bond pairs in liquid silicon is estimated to be 17% via a maximally-localized Wannier function analysis. Compton scattering is shown to be a sensitive probe of bonding effects in the liquid state.Comment: 5pages, 3 postscript figure

How the perceived neighbourhood environment influences active living in older dwellers of an Asian ultra-dense metropolis

The way older adults perceive their neighbourhood environment may determine their levels of physical activity. We examined the associations of perceived neighbourhood environmental attributes with accelerometry-assessed and self-reported physical activity and sedentary time in Hong Kong Chinese older adults. In doing so, we estimated the inter-relationships among perceived environmental attributes, the mediating role of physical activity in the environment-sedentary time nexus and the moderating role of sex. We used data from the Active Lifestyle and the Environment in Chinese Seniors (ALECS) project collected on older adults (N = 909; ≥65 years) living in neighbourhoods varying in walkability and socio-economic status (71 % response rate). Self-reported physical activity and perceived neighbourhood attributes were assessed with validated questionnaires. Accelerometer-based physical activity and sedentary time were collected in 402 participants. Older adults who perceived their neighbourhood to be walkable, safe, aesthetically pleasing and equipped with public sitting facilities engaged in more physical activity and less sedentary time. Curvilinear relations of perceived residential density and activity-friendly urban design features indicated that extreme levels of density may not be optimal for older adults to adopt an active lifestyle because they do not provide sufficient space for sitting facilities and greenery and do not result in better perceptions of neighbourhood walkability when compared to areas with moderate-to-high levels of density. Creative solutions for the incorporation of greenery and public places for sitting in megacities are needed

Effects of alpha-lactalbumin or whey protein isolate on muscle damage, muscle pain, and mood states following prolonged strenuous endurance exercise

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Polymer Light‐Emitting Transistors With Charge‐Carrier Mobilities Exceeding 1 cm2 V−1 s−1

The vast majority of conjugated polymer-based light emitting field-effect transistors (LEFETs) are characterized by low charge carrier mobilities typically in the range 10-5 to 10-3 cm2 V-1 s-1 range. Fast carrier transport is a highly desirable characteristic for high frequency LEFET operation and, potentially, for use in electrically-pumped lasers. Unfortunately, high mobility organic semiconductors are often characterised by strong intermolecular π-π interactions that reduce luminescence. Development of new materials and/or device concepts that overcome this hurdle are therefore required. We report single organic semiconductor layer, light-emitting transistors that combine the highest hole mobilities reported to date for any polymer-based LEFET, with encouraging light emission characteristics. We achieve this in a single polymer layer LEFET, which was further enhanced through the use of a small-molecule/conjugated polymer blend system that possesses a film microstructure which supports enhanced charge carrier mobility (3.2 cm2 V-1 s-1) and promising light emission characteristics (1600 cd m-2) as compared to polymer-only based LEFETs. This simple approach represents an attractive strategy to further advance the performance of solution-processed LEFETs

Effects of metallic spacer in layered superconducting Sr2(Mgy_yTi1−y_{1-y})O3FeAs

The highly two-dimensional superconducting system Sr2(Mg$_y$Ti$_{1-y}$)O3FeAs, recently synthesized in the range of 0.2 < y < 0.5, shows an Mg concentration-dependent $T_c$. Reducing the Mg concentration from y=0.5 leads to a sudden increase in $T_c$, with a maximum $T_c$ ~40 K at y=0.2. Using first principles calculations, the unsynthesized stoichiometric y=0 and the substoichiometric y=0.5 compounds have been investigated. For the 50% Mg-doped phase (y=0.5), Sr2(Mg$_y$Ti$_{1-y}$)O3 layers are completely insulating spacers between FeAs layers, leading to the fermiology such as that found for other Fe pnictides. At y=0, representing a phase with metallic Sr2TiO3 layers, the $\Gamma$-centered Fe-derived Fermi surfaces (FSs) considerably shrink or disappear. Instead, three $\Gamma$-centered Ti FSs appear, and in particular two of them have similar size, like in MgB2. Interestingly, FSs have very low Fermi velocity in large fractions: the lowest being 0.6$\times10^6$ cm/s. Furthermore, our fixed spin moment calculations suggest the possibility of magnetic ordering, with magnetic Ti and nearly nonmagnetic Fe ions. These results indicate a crucial role of Sr2(Mg$_y$Ti$_{1-y}$)O3 layers in this superconductivity.Comment: 7 pages; Proceedings of ICSM-201

Evaluation of the Sustaining Effects of Tai Chi Qigong in the Sixth Month in Promoting Psychosocial Health in COPD Patients: A Single-Blind, Randomized Controlled Trial

Objectives. To evaluate the sustaining effects of Tai Chi Qigong (TCQ) in improving the psychosocial health in chronic obstructive pulmonary disease (COPD) patients in the sixth month. Background. COPD affects both physical and emotional aspects of life. Measures to minimize patients' suffering need to be implemented. Methods. 206 COPD patients were randomly assigned into three groups: TCQ group, exercise group, and control group. The TCQ group completed a three-month TCQ program, the exercise group practiced breathing and walking exercise, and the control group received usual care. Results. Significant group-by-time interactions in quality of life (QOL) using St. George's respiratory questionnaire (P = 0.002) and the perceived social support from friends using multidimensional scale of perceived social support (P = 0.04) were noted. Improvements were observed in the TCQ group only. Conclusions. TCQ has sustaining effects in improving psychosocial health; it is also a useful and appropriate exercise for COPD patients

Global-local dynamics in the transformation of the Jakarta Metropolitan Area into a global city-region

This paper investigates the way in which factors at the global and local level interact in the emergence and development of “global city-regions”, which are deemed to be the contemporary growth machines of the global economy. To this end, this paper takes the Jakarta metropolitan area (JMA) as a case to investigate its evolution in the context of the intertwined dynamics of foreign direct investment (FDI) inflow and state intervention over the past three decades. The findings indicate that from a macro-level perspective the JMA has maintained its position as the country’s hotspot for manufacturing investment embedded in East Asian production networks. In addition, we find that the national state has continuously privileged the JMA as the main grounds for national economic development in spite of the country’s shifting political system. We reveal how the nexus between “global” forces (incoming FDI) and “local” conditions (the state’s strategic intervention) has led to the development and restructuring of the JMA as a global city-region

Pan-viral serology implicates enteroviruses in acute flaccid myelitis.

Since 2012, the United States of America has experienced a biennial spike in pediatric acute flaccid myelitis (AFM)1-6. Epidemiologic evidence suggests non-polio enteroviruses (EVs) are a potential etiology, yet EV RNA is rarely detected in cerebrospinal fluid (CSF)2. CSF from children with AFM (n = 42) and other pediatric neurologic disease controls (n = 58) were investigated for intrathecal antiviral antibodies, using a phage display library expressing 481,966 overlapping peptides derived from all known vertebrate and arboviruses (VirScan). Metagenomic next-generation sequencing (mNGS) of AFM CSF RNA (n = 20 cases) was also performed, both unbiased sequencing and with targeted enrichment for EVs. Using VirScan, the viral family significantly enriched by the CSF of AFM cases relative to controls was Picornaviridae, with the most enriched Picornaviridae peptides belonging to the genus Enterovirus (n = 29/42 cases versus 4/58 controls). EV VP1 ELISA confirmed this finding (n = 22/26 cases versus 7/50 controls). mNGS did not detect additional EV RNA. Despite rare detection of EV RNA, pan-viral serology frequently identified high levels of CSF EV-specific antibodies in AFM compared with controls, providing further evidence for a causal role of non-polio EVs in AFM

Thin-Film Metamaterials called Sculptured Thin Films

Morphology and performance are conjointed attributes of metamaterials, of which sculptured thin films (STFs) are examples. STFs are assemblies of nanowires that can be fabricated from many different materials, typically via physical vapor deposition onto rotating substrates. The curvilinear--nanowire morphology of STFs is determined by the substrate motions during fabrication. The optical properties, especially, can be tailored by varying the morphology of STFs. In many cases prototype devices have been fabricated for various optical, thermal, chemical, and biological applications.Comment: to be published in Proc. ICTP School on Metamaterials (Augsut 2009, Sibiu, Romania