Detection and Classification of Volatile Organic Amines and Carboxylic Acids Using Arrays of Carbon Black-Dendrimer Composite Vapor Detectors

Carbon black-insulator composite chemiresistive vapor detectors have been prepared using dendrimers as the polymeric constituent of the composite. Amino-terminated dendrimer-carbon black composites exhibited an enhancement in detection sensitivity of ∼10^3 for volatile carboxylic acids as compared to nondendrimeric insulating polymer-carbon black composites. Similarly, protonated carboxylato-terminated and protonated amino-terminated dendrimer-carbon black composites showed an ∼10^3−10^4 increase in sensitivity for detection of volatile amines relative to the response of nondendrimeric insulating polymer-carbon black composites. The protonated amino-terminated dendrimer carbon black composite detectors exhibited a signal-to-noise ratio (S/N) of 22.4 ± 0.9 upon exposure to 2.7 ppb of butylamine in air, whereas poly(ethylene oxide)-carbon black composites exhibited a S/N of 3.5 ± 1.2 at 54 ppm of butylamine. The protonated amino-terminated dendrimer-carbon black detectors additionally exhibited relatively small responses to water vapor. Compositional diversity in an array of protonated amino-terminated dendrimeric vapor detectors was obtained by varying the type and generation of the dendrimer, and the type and concentration of the acid dopant. Fifteen analytes chosen from primary amines, branched amines, anilines, and non-amine organic analyte vapors were all robustly discriminated from each other by their different response patterns on the dendrimer-containing detector array. The signals produced by these 15 analytes additionally clustered into groups based on the chemical class of the analyte

Effects of Co substitution on thermodynamic and transport properties and anisotropic Hc2H_{c2} in Ba(Fe1−x_{1-x}Cox_x)2_2As2_2 single crystals

Single crystalline samples of Ba(Fe$_{1-x}$Co$_x$)$_2$As$_2$ with $x < 0.12$ have been grown and characterized via microscopic, thermodynamic and transport measurements. With increasing Co substitution, the thermodynamic and transport signatures of the structural (high temperature tetragonal to low temperature orthorhombic) and magnetic (high temperature non magnetic to low temperature antiferromagnetic) transitions are suppressed at a rate of roughly 15 K per percent Co. In addition, for $x \ge 0.038$ superconductivity is stabilized, rising to a maximum $T_c$ of approximately 23 K for $x \approx 0.07$ and decreasing for higher $x$ values. The $T - x$ phase diagram for Ba(Fe$_{1-x}$Co$_x$)$_2$As$_2$ indicates that either superconductivity can exist in both low temperature crystallographic phases or that there is a structural phase separation. Anisotropic, superconducting, upper critical field data ($H_{c2}(T)$) show a significant and clear change in anisotropy between samples that have higher temperature structural phase transitions and those that do not. These data show that the superconductivity is sensitive to the suppression of the higher temperature phase transition

Vulture-Cattle Interactions at a Central Florida Ranch

Black vulture depredations to newborn livestock, poultry, and other captive animals have been reported from at least 15 states, and during the 1990s, reports of depredations increased annually by an average of 18%. In response to this issue, we initiated a study at Buck Island Ranch of the MacArthur Agro-Ecology Research Center in central Florida to examine interactions between cattle and vultures. Based on previous reports, we hypothesized that vulture predation selectively targets calves of young, inexperienced cows. To document vulture activity, we conducted point counts of vultures in pastures throughout the ranch from January 2000 to March 2001. During point counts, turkey vultures accounted for 78% of the observations compared to 22% for black vultures. We noted that vultures used certain pastures preferentially, with over 70% of the vultures in 3 pastures where heifers were calving and the remainder spread among 7 pastures containing yearling heifers only or cows and calves. Turkey and black vultures were often present during the 19 calving events we observed, but usually neither species exhibited threatening behavior toward calves or calving heifers. Instead, the birds seemed intent on gaining access to the afterbirth. On one occasion, however, we observed an attempted depredation by black vultures on a calf as it was being born. The cow was able to chase the buds off, however, and the birth proceeded successfully. We conclude that predation by black vultures occurs when the buds identify and then exploit vulnerable animals, although there is still much to be learned regarding the circumstances that promote such activity. b e n t management recommendations include dispersing nearby black vulture roosts and providing careful oversight to protect inexperienced cows that are first-time breeders

Estimating Taxonomic Diversity Using Centrum Growth Profiles and Stinger Morphology of 36 Million Year Old Stingrays From North Dakota

Stingrays are a diverse and popular group of vertebrates; however, nothing is known about the relationships between growth biology and climate change. Freshwater stingrays once inhabit the United States and Canada during very warm times in the geologic record. No stingray material has been recorded from the northern part of the United States for the last 33 million years. The Earth’s climate cooled from 50 to 33 million year ago when many warm adapted organisms were relegated to warmer, southern latitudes in North America. Today, freshwater stingrays only inhabit subtropical and tropical environments. We are interested in the freshwater stingrays that lived just prior to the climatic cooling that changed the area of what is now North Dakota 33 million years ago. Our goal was to estimate alpha diversity of stingrays from a fluvial fossil deposit that existed 34 million years ago. We predicted the fossil stingrays from North Dakota to grow very slow compared to their modern counterparts. Fossil elements of stingrays are represented by their individual vertebral centra, stingers, and teeth. No complete specimens have been identified. We examined 36 isolated vertebral centra and estimated the number of growth cessation marks on each centrum. Centrum radial distance (mm) was measured from the notochord foramen to each annulus and plotted. We could not find any published data on age and growth of extant freshwater stingrays for comparison. The growth profiles were compared to marine Dasyatis pastinaca, Common Stingray, which are found in Northeastern Atlantic Ocean. There is complete overlap in the von Bertalanffy growth curves and parameters of the two datasets with no evidence for slow growth rates from ages 1-7 years old. Stingers were described morphologically and stinger thickness and median ridge thickness (mm) was measured for each specimen. Chronological ages for individual specimens ranged from 0 to 8 years old with two significantly distinct growth profiles; small and large profiles. Three stinger morphotypes were recognized. Measurements of stinger median ridge thickness indicated there were two small morphotypes and one significantly larger morphotype. Our data suggest there were three taxa of stingrays that lived in the river channels of North Dakota 36 million years ago. Two taxa were small and one taxon was somewhat larger. Our next goal is to determine whether there are three distinct morphologies in the vertebral centra. There is little evidence of old individuals in the fossil dataset suggesting two hypotheses; 1) older individuals did not exist in the population, and 2) older individuals lived in another habitat (habitat partitioning). The use of fossils stands to provide great insight into the effects of climate change on the age and growth biology of fishes. Our research indicates that diversity of freshwater stingrays was higher than expected. Climatic cooling may have caused regional extinctions of freshwater stingrays because freshwater stingrays are found in tropical and subtropical areas today

Pharmacologic Treatment for Pediatric Gastroparesis: A Review of the Literature

There have been a number of agents that have been tried for treatment of gastroparesis over the past 3 decades, with varying levels of success. Guidelines exist for the management of gastroparesis in adults; however, even though the cause of gastroparesis in children is similar to that in adults, no guidelines exist for treating pediatric gastroparesis as studies on the topic are limited. With what little information we have on pediatric gastroparesis, medications used in children's studies do not seem to demonstrate the same results as in adult patients with gastroparesis; thus, future studies of whether certain medications are effective for treating pediatric gastroparesis and at what dose still need to be conducted. Pharmacological treatment options for pediatric gastroparesis do not show a clear correlation of resolving or even maintaining gastroparesis-associated symptoms or disease state. This article reviews the available studies of drugs that have shown some efficacy, with an emphasis on pediatric studies

The role of life cycle assessment in evaluating alternatives for electrification of roads and long haul trucks in Sweden

In September 2012, the Swedish Government presented a 1.3 billion SEK investment for the years 2013-2016 targeted on improving the infrastructure for transportation of iron ore powder between the mine in Kaunisvaara and Svappavaara, where it is transferred to train. This decision was preceded by an official report from the Swedish Transport Administration investigating necessary road reconstruction along with alternatives for electrification of the vehicles used. As a result, a new road of 140 kilometers will be constructed and at the same time serve as test project for electric road technologies in Sweden, with the initial focus set on heavy duty trucks.Scania CV AB is the supplier of the 90 ton long haul trucks which will transport the iron ore powder, and also an active part in the rapidly evolving area of electric roads in Sweden. In August 2012, the company’s Hybrid Systems Development Department initiated a life cycle assessment (LCA) on this case, set up in the form of a master’s thesis.The LCA study compares three different drivetrain alternatives for the heavy long haul trucks. In essence, the cradle to grave cycle impact of a set of additional components is compared with the effect of the reduced total energy use of fuel and electricity in the well-to-wheel phase, for a conventional truck, a hybrid (made more efficient by integrating electric propulsion) and a hybrid with external power supply from the road. The aim of the study is to evaluate the environmental impact of the three alternatives and to demonstrate how it changes over the different life cycle phases.The motive of Scania has been to increase their knowledge of the environmental impacts of drivetrain electrification, and also to provide support for internal decisions and future strategies on how to meet energy efficiency targets. The idea is also to present the results within the test project working group and thereby contribute to the overall project evaluation.The aim of this presentation is to point out that the increased governmental focus on electric roads in Sweden and Scania’s need to understand the effect of this technology in an environmental systems perspective, has given LCA a role in the evaulation. Hence, the results and conclusions of the LCA will be presented. Finally, the opportunities and limitations of LCA as a learning tool when applied on this type of emerging technology at a department with no prior LCA experience will be discussed

Bright betatron x-ray radiation from a laser-driven-clustering gas target

Hard X-ray sources from femtosecond (fs) laser-produced plasmas, including the betatron X-rays from laser wakefield-accelerated electrons, have compact sizes, fs pulse duration and fs pump-probe capability, making it promising for wide use in material and biological sciences. Currently the main problem with such betatron X-ray sources is the limited average flux even with ultra-intense laser pulses. Here, we report ultra-bright betatron X-rays can be generated using a clustering gas jet target irradiated with a small size laser, where a ten-fold enhancement of the X-ray yield is achieved compared to the results obtained using a gas target. We suggest the increased X-ray photon is due to the existence of clusters in the gas, which results in increased total electron charge trapped for acceleration and larger wiggling amplitudes during the acceleration. This observation opens a route to produce high betatron average flux using small but high repetition rate laser facilities for applications

The Two-Stage Ipsilateral Fibular Transfer for Tibial Defect Following Tumour Excision

Method. We performed a two-stage vascularized ipsilateral fibular graft transfer for segmental tibial defect following excision of malignant bone tumours

Momentum dependence of the superconducting gap in NdFeAsO1-xFx single crystals measured by angle resolved photoemission spectroscopy

We use angle resolved photoemission spectroscopy (ARPES) to study the momentum dependence of the superconducting gap in NdFeAsO1-xFx single crystals. We find that the Gamma hole pocket is fully gapped below the superconducting transition temperature. The value of the superconducting gap is 15 +- 1.5 meV and its anisotropy around the hole pocket is smaller than 20% of this value. This is consistent with an isotropic or anisotropic s-wave symmetry of the order parameter or exotic d-wave symmetry with nodes located off the Fermi surface sheets. This is a significant departure from the situation in the cuprates, pointing to possibility that the superconductivity in the iron arsenic based system arises from a different mechanism.Comment: 4 pages, 3 figure