Direct Visualization of Independent Ta Centers Supported on Two-Dimensional TiO2 Nanosheets

Highly-dispersed, supported oxides are ubiquitous solid catalysts, but they can be challenging to characterize with atomic precision. Here it is shown that crystalline anatase TiO2 nanosheets (~5 nm thick) are ideal supports for imaging highly-dispersed active sites. Ta cations are deposited by several routes, and high-resolution high angle annular dark-field (HAADF) scanning transmission electron microscopy (STEM) is used to determine the location of Ta with respect to the TiO2 lattice and to quantify Ta-Ta distances. In the best case, it is shown that >80% of Ta atoms are isolated from one another, whereas other techniques are blind to this critical catalytic property or give only qualitative estimates. TiO2 nanosheets may prove to be a useful platform for other types of catalysis studies

A miniaturised autonomous sensor based on nanowire materials platform: the SiNAPS mote

A micro-power energy harvesting system based on core(crystalline Si)-shell(amorphous Si) nanowire solar cells together with a nanowire-modified CMOS sensing platform have been developed to be used in a dust-sized autonomous chemical sensor node. The mote (SiNAPS) is augmented by low-power electronics for power management and sensor interfacing, on a chip area of 0.25mm2. Direct charging of the target battery (e.g., NiMH microbattery) is achieved with end-to-end efficiencies up to 90% at AM1.5 illumination and 80% under 100 times reduced intensity. This requires matching the voltages of the photovoltaic module and the battery circumventing maximum power point tracking. Single solar cells show efficiencies up to 10% under AM1.5 illumination and open circuit voltages, Voc, of 450-500mV. To match the battery’s voltage the miniaturised solar cells (~1mm2 area) are connected in series via wire bonding. The chemical sensor platform (mm2 area) is set up to detect hydrogen gas concentration in the low ppm range and over a broad temperature range using a low power sensing interface circuit. Using Telran TZ1053 radio to send one sample measurement of both temperature and H2 concentration every 15 seconds, the average and active power consumption for the SiNAPS mote are less than 350nW and 2.1 μW respectively. Low-power miniaturised chemical sensors of liquid analytes through microfluidic delivery to silicon nanowires are also presented. These components demonstrate the potential of further miniaturization and application of sensor nodes beyond the typical physical sensors, and are enabled by the nanowire materials platform

Role of surface reconstruction on Cu/TiO2 nanotubes for CO2 conversion

Carbon dioxide hydrogenation to CO via the reverse water gas shift (RWGS) reaction is one route to integrate CO2 utilization into the chemical industry. TiO2 supported Cu catalysts are known to be active for RWGS, but Cu is shown here to behave differently on TiO2 nanotubes (TiNT) vs TiO2 nanoparticles (TiNP). Whereas nanoparticle supports give low rates that are hardly changed by added Cu, the nanotube supports yield much higher activity and three distinct behaviors as the Cu surface density increases. At low surface densities (0.3 Cu/nm2), active Cu-O-Ti sites are created that have low apparent activation energies. At high surface densities (6 Cu/nm2), Cu nanoparticles on TiNT are formed, and reaction barriers are lowered when both Cu and TiNT surfaces are accessible. At intermediate surface densities, metallic Cu domains are engulfed by a TiOx overlayer formed during H2 pretreatment, akin to those formed by classical strong metal support interactions (SMSI). These reduced layers are markedly more active for RWGS than the initial TiNT surfaces, but have similar activation barriers, which are higher than those for which both Cu and TiNP surfaces are exposed. These catalytic findings are supported by computational modeling, in situ IR, UV–vis, and X-ray absorption spectroscopies, and they provide insight into an important reaction for CO2 utilization

Association Between Hospital Cardiac Catheter Laboratory Status, Use of an Invasive Strategy, and Outcomes After NSTEMI

The authors gratefully acknowledge the contributions of all of the hospitals and health professionals who participate in the MINAP registry.Peer reviewedPostprin

Highly stable PEGylated gold nanoparticles in water: applications in biology and catalysis

Here we report the synthesis of well dispersed gold nanoparticles (Au NPs), with diameters ranging between 5 and 60 nm, in water and demonstrate their potential usefulness in catalysis and biological applications. Functionalised polyethylene glycol-based thiol polymers (mPEG-SH) were used to stabilise the pre-synthesised NPs. Successful PEGylation of the NPs was confirmed by Dynamic Light Scattering (DLS) and zeta potential measurements. PEG coating of the NPs was found to be key to their colloidal stability in high ionic strength media, compared to bare citrate-stabilised NPs. Our results show that PEG–Au NPs with diameters <30 nm were useful as catalysts in the homocoupling of arylboronic acids in water. Additionally, PEG–Au NPs were also shown to be stable in biological fluids, non-cytotoxic to B16.F10 and CT-26 cell lines and able to successfully deliver siRNA to CT-26 cells, achieving a significant reduction (p < 0.05) in the expression levels of luciferase protein; making these NPs attractive for further biological studies

A scalable, fully automated process for construction of sequence-ready human exome targeted capture libraries

Genome targeting methods enable cost-effective capture of specific subsets of the genome for sequencing. We present here an automated, highly scalable method for carrying out the Solution Hybrid Selection capture approach that provides a dramatic increase in scale and throughput of sequence-ready libraries produced. Significant process improvements and a series of in-process quality control checkpoints are also added. These process improvements can also be used in a manual version of the protocol

Monolayer doping of germanium with arsenic: A new chemical route to achieve optimal dopant activation

Reported here is a new chemical route for the wet chemical functionalization of germanium (Ge), whereby arsanilic acid is covalently bound to a chlorine (Cl)-terminated surface. This new route is used to deliver high concentrations of arsenic (As) dopants to Ge, via monolayer doping (MLD). Doping, or the introduction of Group III or Group V impurity atoms into the crystal lattice of Group IV semiconductors, is essential to allow control over the electronic properties of the material to enable transistor devices to be switched on and off. MLD is a diffusion-based method for the introduction of these impurity atoms via surface-bound molecules, which offers a nondestructive alternative to ion implantation, the current industry doping standard, making it suitable for sub-10 nm structures. Ge, given its higher carrier mobilities, is a leading candidate to replace Si as the channel material in future devices. Combining the new chemical route with the existing MLD process yields active carrier concentrations of dopants (>1 × 1019 atoms/cm3) that rival those of ion implantation. It is shown that the dose of dopant delivered to Ge is also controllable by changing the size of the precursor molecule. X-ray photoelectron spectroscopy (XPS) data and density functional theory (DFT) calculations support the formation of a covalent bond between the arsanilic acid and the Cl-terminated Ge surface. Atomic force microscopy (AFM) indicates that the integrity of the surface is maintained throughout the chemical procedure, and electrochemical capacitance voltage (ECV) data shows a carrier concentration of 1.9 × 1019 atoms/cm3 corroborated by sheet resistance measurements

Cognition, culture and utility:Plant classification by Paraguayan immigrant farmers in Misiones, Argentina

Background: This study was conducted in three rural communities of small farmers of Paraguayan origin living in the province of Misiones, Argentina. These Criollos (Mestizos) hail chiefly from departments located in the east of Paraguay, where the climate and flora have similar characteristics as those in Misiones. These ecological features contribute to the continuation and maintenance of knowledge and practices related to the use of plants. Methods: Fieldwork was conducted between September 2014 and August 2015. Forty five informants from three rural localities situated along the Parana River participated in an ethno-classification task. For the classification event, photographs of 30 medicinal and edible plants were chosen, specifically those yielding the highest frequency of mention among the members of that community (based on data obtained in the first stage of research in 2014). Variation in local plant classifications was examined and compared using principal component analysis and cluster analysis. Results: We found that people classify plants according to application or use (primarily medicinal, to a lesser extent as edible). Morphology is rarely taken into account, even for very similar and closely-related species such as varieties of palms. In light of our findings, we highlight a dominant functionality model at work in the process of plant cognition and classification among farmers of Paraguayan origin. Salient cultural beliefs and practices associated with rural Paraguayan plant-based medicine are described. Additionally, the manner by which residents’ concepts of plants articulate with local folk epistemology is discussed. Conclusions: Culturally constructed use patterns ultimately override morphological variables in rural Paraguayans’ ethnobotanical classification.Antecedentes: Este trabajo se realizó con pequeños agricultores de origen paraguayo, que habitan en la provincia de Misiones, Argentina. Los criollos (mestizos) en su mayoría provienen de departamentos ubicados al oriente del Paraguay, donde el clima y la flora presentan características similares a la provincia de Misiones. Estas características ecológicas contribuyen a la continuación y el mantenimiento de los conocimientos y las prácticas relacionados al uso de las plantas. Métodos El trabajo de campo se realizó entre septiembre de 2014 y agosto de 2015. En la etnoclasificación participaron 45 informantes, provenientes de tres localidades rurales, situadas a lo largo del río Paraná, frontera entre los dos países. Para la clasificación se utilizaron imágenes fotográficas de 30 especies -comestibles y medicinales- preseleccionadas como las de mayor frecuencia de mención entre los habitantes de la región (a partir de los datos obtenidos en una primera etapa de investigación en el año 2014). Por medio del análisis de componentes principales y el análisis de agrupamiento (cluster) se contrastaron y compararon las variaciones en las etnoclasificaciones locales de plantas. Resultados Se encontró que los pobladores clasifican sus plantas según su aplicación y uso (mayormente asociadas a la categoría medicinal y en menor medida a la comestible). Mientras, la morfología rara vez se tiene en cuenta, incluso en aquellas especies muy similares y estrechamente relacionadas como las palmeras. A la luz de los hallazgos, se destaca un modelo de funcionalidad dominante en el proceso de cognición y de clasificación de las plantas entre los agricultores de origen paraguayo. Se describen las principales creencias y prácticas culturales asociadas a la medicina rural paraguaya. Adicionalmente, se discuten algunos de los conceptos de las plantas que mantienen los paraguayos y su articulación con la epistemología local. Conclusiones En la clasificación etnobotánica de los pobladores de origen paraguayo los patrones de uso construidos culturalmente tienen mayor peso que las variables morfológicas.Fil: Kujawska, Monika. University Of Lodz; ArgentinaFil: Jiménez Escobar, Néstor David. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Antropología de Córdoba. Universidad Nacional de Córdoba. Facultad de Filosofía y Humanidades. Instituto de Antropología de Córdoba; ArgentinaFil: Nolan, Justin M.. University Of Arkansas; Estados UnidosFil: Arias Mutis, Daniel. University of Groningen; Países Bajo

Fermi Large Area Telescope Constraints on the Gamma-ray Opacity of the Universe

The Extragalactic Background Light (EBL) includes photons with wavelengths from ultraviolet to infrared, which are effective at attenuating gamma rays with energy above ~10 GeV during propagation from sources at cosmological distances. This results in a redshift- and energy-dependent attenuation of the gamma-ray flux of extragalactic sources such as blazars and Gamma-Ray Bursts (GRBs). The Large Area Telescope onboard Fermi detects a sample of gamma-ray blazars with redshift up to z~3, and GRBs with redshift up to z~4.3. Using photons above 10 GeV collected by Fermi over more than one year of observations for these sources, we investigate the effect of gamma-ray flux attenuation by the EBL. We place upper limits on the gamma-ray opacity of the Universe at various energies and redshifts, and compare this with predictions from well-known EBL models. We find that an EBL intensity in the optical-ultraviolet wavelengths as great as predicted by the "baseline" model of Stecker et al. (2006) can be ruled out with high confidence.Comment: 42 pages, 12 figures, accepted version (24 Aug.2010) for publication in ApJ; Contact authors: A. Bouvier, A. Chen, S. Raino, S. Razzaque, A. Reimer, L.C. Reye

First Things First: Effectiveness and Scalability of a Basic Prehospital Trauma Care Program for Lay First-Responders in Kampala, Uganda

BACKGROUND: We previously showed that in the absence of a formal emergency system, lay people face a heavy burden of injuries in Kampala, Uganda, and we demonstrated the feasibility of a basic prehospital trauma course for lay people. This study tests the effectiveness of this course and estimates the costs and cost-effectiveness of scaling up this training. METHODS AND FINDINGS: For six months, we prospectively followed 307 trainees (police, taxi drivers, and community leaders) who completed a one-day basic prehospital trauma care program in 2008. Cross-sectional surveys and fund of knowledge tests were used to measure their frequency of skill and supply use, reasons for not providing aid, perceived utility of the course and kit, confidence in using skills, and knowledge of first-aid. We then estimated the cost-effectiveness of scaling up the program. At six months, 188 (62%) of the trainees were followed up. Their knowledge retention remained high or increased. The mean correct score on a basic fund of knowledge test was 92%, up from 86% after initial training (n = 146 pairs, p = 0.0016). 97% of participants had used at least one skill from the course: most commonly haemorrhage control, recovery position and lifting/moving and 96% had used at least one first-aid item. Lack of knowledge was less of a barrier and trainees were significantly more confident in providing first-aid. Based on cost estimates from the World Health Organization, local injury data, and modelling from previous studies, the projected cost of scaling up this program was $0.12 per capita or$25-75 per life year saved. Key limitations of the study include small sample size, possible reporter bias, preliminary local validation of study instruments, and an indirect estimate of mortality reduction. CONCLUSIONS: Lay first-responders effectively retained knowledge on prehospital trauma care and confidently used their first-aid skills and supplies for at least six months. The costs of scaling up this intervention to cover Kampala are very modest. This may be a cost-effective first step toward developing formal emergency services in Uganda other resource-constrained settings. Further research is needed in this critical area of trauma care in low-income countries