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Author Guedje, F.K.; Giloan, M.; Potara, M.; Hounkonnou, M.N.; Astilean, S. file  url
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  Title Optical properties of single silver triangular nanoprism Type Journal Article
  Year 2012 Publication Physica Scripta Abbreviated Journal Phys. Scr.  
  Volume 86 Issue 5 Pages (down) 055702  
  Keywords  
  Abstract The ability to provide large electric field enhancements renders triangular nanoprisms and branched nanoparticles very attractive for applications in surface-enhanced Raman spectroscopy (SERS). Theoretical studies on the optical properties of triangular prisms in a water solution are presented in this paper to determine how structural modifications and incident field polarization affect the extinction spectrum and enhanced local electric fields (E-field) around particles in the wavelength range of 300 to 1000 nm. The near-field properties, such as the E-field close to the particle, determine the electromagnetic enhancements in SERS. The optical response of a triangular nanoprism can be fully characterized using three different orientations of the incident field polarization. The orientations where the polarization vector is parallel to the triangular cross section are the most important for the overall extinction, rather than those where the polarization vector is perpendicular to the plane. The extinction spectrum presents three distinct localized surface plasmon resonances (LSPRs) for a silver triangular nanoprism. These are assigned as in-plane dipolar and quadrupolar plasmon excitations using electrodynamic modeling based on the finite difference time domain. The dipole resonance is found to be very intense, and its peak wavelength is extremely sensitive to the thickness and edge length of the nanoprism. In contrast, the intensity of the quadrupole resonances is much weaker relative to the dipole resonance. The distribution of the local field around the particle at specified wavelengths, showing the values of the peak field, is presented. All the LSPRs are clearly resolved in the visible. The experimental data are used for comparison. These new spectral features are very promising in the field of nano-optics and for bio-sensing applications.

Subject headings: Nanoprisms; Nanoparticles; Raman spectroscopy (SERS)

Keywords: Optical properties of single silver triangular nanoprism
 
  Call Number Serial 2454  
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Author Zaharieva, I.; Chernev, P.; Risch, M.; Klingan, K.; Kohlhoff, M.; Fischer, A.; Dau, H. file  url
openurl 
  Title Electrosynthesis, functional, and structural characterization of a water-oxidizing manganese oxide Type Journal Article
  Year 2012 Publication Energy & Environmental Science Abbreviated Journal Energy Environ. Sci.  
  Volume 5 Issue 5 Pages (down) 7081  
  Keywords  
  Abstract In the sustainable production of non-fossil fuels, water oxidation is pivotal. Development of efficient catalysts based on manganese is desirable because this element is earth-abundant, inexpensive, and largely non-toxic. We report an electrodeposited Mn oxide (MnCat) that catalyzes electrochemical water oxidation at neutral pH at rates that approach the level needed for direct coupling to photoactive materials. By choice of the voltage protocol we could switch between electrodeposition of inactive Mn oxides (deposition at constant anodic potentials) and synthesis of the active MnCat (deposition by voltage-cycling protocols). Electron microscopy reveals that the MnCat consists of nanoparticles (100 nm) with complex fine-structure. X-ray spectroscopy reveals that the amorphous MnCat resembles the biological paragon, the water-splitting Mn4Ca complex of photosynthesis, with respect to mean Mn oxidation state (ca. +3.8 in the MnCat) and central structural motifs. Yet the MnCat functions without calcium or other bivalent ions. Comparing the MnCat with electrodeposited Mn oxides inactive in water oxidation, we identify characteristics that likely are crucial for catalytic activity. In both inactive Mn oxides and active ones (MnCat), extensive di-oxo bridging between Mn ions is observed. However in the MnCat, the voltage-cycling protocol resulted in formation of MnIII sites and prevented formation of well-ordered and unreactive MnIVO2. Structure-function relations in Mn-based water-oxidation catalysts and strategies to design catalytically active Mn-based materials are discussed. Knowledge-guided performance optimization of the MnCat could pave the road for its technological use.

Subject Headings: Characterization; Manganese oxide; Electrosynthesis

Keywords: Electrosynthesis, functional, and structural characterization of a water-oxidizing manganese oxide
 
  Call Number Serial 2631  
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Author Berglund, S.P.; Rettie, A.J.E.; Hoang, S.; Mullins, C.B. file  url
openurl 
  Title Incorporation of Mo and W into nanostructured BiVO4 films for efficient photoelectrochemical water oxidation Type Journal Article
  Year 2012 Publication Physical Chemistry Chemical Physics : PCCP Abbreviated Journal Phys Chem Chem Phys  
  Volume 14 Issue 19 Pages (down) 7065-7075  
  Keywords BiV04; Simultaneous evaporation  
  Abstract Porous, nanostructured BiVO4 films are incorporated with Mo and W by simultaneous evaporation of Bi, V, Mo, and W in vacuum followed by oxidation in air. Synthesis parameters such as the Bi : V : Mo : W atomic ratio and deposition angle are adjusted to optimize the films for photoelectrochemical (PEC) water oxidation. Films synthesized with a Bi : V : Mo : W atomic ratio of 46 : 46 : 6 : 2 (6% Mo, 2% W) demonstrate the best PEC performance with photocurrent densities 10 times higher than for pure BiVO4 and greater than previously reported for Mo and W containing BiVO4. The films consist of a directional, nanocolumnar layer beneath an irregular surface structure. Backside illumination utilizes light scattering off the irregular surface structure resulting in 30-45% higher photocurrent densities than for frontside illumination. To improve the kinetics for water oxidation Pt is photo-deposited onto the surface of the 6% Mo, 2% W BiVO4 films as an electrocatalyst. These films achieve quantum efficiencies of 37% at 1.1 V vs. RHE and 50% at 1.6 V vs. RHE for 450 nm light.  
  Call Number Serial 1433  
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Author Howard, D.M.; Wylie, B.K.; Tieszen, L.L. file  url
openurl 
  Title Crop classification modelling using remote sensing and environmental data in the Greater Platte River Basin, USA Type Journal Article
  Year 2012 Publication International Journal of Remote Sensing Abbreviated Journal International Journal of Remote Sensing  
  Volume 33 Issue 19 Pages (down) 6094-6108  
  Keywords Crop Classification Modelling; Remote Sensing; Platte River Basin  
  Abstract With an ever expanding population, potential climate variability and an increasing demand for agriculture-based alternative fuels, accurate agricultural land-cover classification for specific crops and their spatial distributions are becoming critical to researchers, policymakers, land managers and farmers. It is important to ensure the sustainability of these and other land uses and to quantify the net impacts that certain management practices have on the environment. Although other quality crop classification products are often available, temporal and spatial coverage gaps can create complications for certain regional or time-specific applications. Our goal was to develop a model capable of classifying major crops in the Greater Platte River Basin (GPRB) for the post-2000 era to supplement existing crop classification products. This study identifies annual spatial distributions and area totals of corn, soybeans, wheat and other crops across the GPRB from 2000 to 2009. We developed a regression tree classification model based on 2.5 million training data points derived from the National Agricultural Statistics Service (NASS) Cropland Data Layer (CDL) in relation to a variety of other relevant input environmental variables. The primary input variables included the weekly 250 m US Geological Survey Earth Observing System Moderate Resolution Imaging Spectroradiometer normalized differential vegetation index, average long-term growing season temperature, average long-term growing season precipitation and yearly start of growing season. An overall model accuracy rating of 78% was achieved for a test sample of roughly 215 000 independent points that were withheld from model training. Ten 250 m resolution annual crop classification maps were produced and evaluated for the GPRB region, one for each year from 2000 to 2009. In addition to the model accuracy assessment, our validation focused on spatial distribution and county-level crop area totals in comparison with the NASS CDL and county statistics from the US Department of Agriculture (USDA) Census of Agriculture. The results showed that our model produced crop classification maps that closely resembled the spatial distribution trends observed in the NASS CDL and exhibited a close linear agreement with county-by-county crop area totals from USDA census data (R 2 = 0.90).  
  Call Number Serial 907  
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Author Baytekin, H.T.; Baytekin, B.; Incorvati, J.T.; Grzybowski, B.A. file  url
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  Title Material transfer and polarity reversal in contact charging Type Journal Article
  Year 2012 Publication Angewandte Chemie (International ed. in English) Abbreviated Journal Angew Chem Int Ed Engl  
  Volume 51 Issue 20 Pages (down) 4843-4847  
  Keywords Electric Conductivity; Energy Transfer; Microscopy, Atomic Force; Molecular Structure; Polystyrenes--chemistry; Polytetrafluoroethylene--chemistry; Spectrum Analysis, Raman; Static Electricity; Surface Properties  
  Abstract In touch: the outcome of contact electrification between dielectrics depends not only on the transfer of charge but also on the transfer of material. Although only minute quantities of materials are being exchanged during contact, they can reverse the polarity of dielectrics. The reported results corroborate the mosaic model and suggest that the observations are because of the mechanical softness/hardness of the materials.  
  Call Number Serial 425  
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Author Clemson, L.; Fiatarone Singh, M.A.; Bundy, A.; Cumming, R.G.; Manollaras, K.; O'Loughlin, P.; Black, D. file  url
openurl 
  Title Integration of balance and strength training into daily life activity to reduce rate of falls in older people (the LiFE study): randomised parallel trial Type Journal Article
  Year 2012 Publication BMJ (Clinical Research ed.) Abbreviated Journal Bmj  
  Volume 345 Issue Pages (down) e4547  
  Keywords Accidental Falls--prevention & control; Activities of Daily Living; Aged; Aged, 80 and over; Female; Humans; Life Style; Male; Patient Compliance; Postural Balance--physiology; Resistance Training--methods; Treatment Outcome  
  Abstract OBJECTIVES: To determine whether a lifestyle integrated approach to balance and strength training is effective in reducing the rate of falls in older, high risk people living at home. DESIGN: Three arm, randomised parallel trial; assessments at baseline and after six and 12 months. Randomisation done by computer generated random blocks, stratified by sex and fall history and concealed by an independent secure website. SETTING: Residents in metropolitan Sydney, Australia. PARTICIPANTS: Participants aged 70 years or older who had two or more falls or one injurious fall in past 12 months, recruited from Veteran's Affairs databases and general practice databases. Exclusion criteria were moderate to severe cognitive problems, inability to ambulate independently, neurological conditions that severely influenced gait and mobility, resident in a nursing home or hostel, or any unstable or terminal illness that would affect ability to do exercises. INTERVENTIONS: Three home based interventions: Lifestyle integrated Functional Exercise (LiFE) approach (n=107; taught principles of balance and strength training and integrated selected activities into everyday routines), structured programme (n=105; exercises for balance and lower limb strength, done three times a week), sham control programme (n=105; gentle exercise). LiFE and structured groups received five sessions with two booster visits and two phone calls; controls received three home visits and six phone calls. Assessments made at baseline and after six and 12 months. MAIN OUTCOME MEASURES: Primary measure: rate of falls over 12 months, collected by self report. Secondary measures: static and dynamic balance; ankle, knee and hip strength; balance self efficacy; daily living activities; participation; habitual physical activity; quality of life; energy expenditure; body mass index; and fat free mass. RESULTS: After 12 months' follow-up, we recorded 172, 193, and 224 falls in the LiFE, structured exercise, and control groups, respectively. The overall incidence of falls in the LiFE programme was 1.66 per person years, compared with 1.90 in the structured programme and 2.28 in the control group. We saw a significant reduction of 31% in the rate of falls for the LiFE programme compared with controls (incidence rate ratio 0.69 (95% confidence interval 0.48 to 0.99)); the corresponding difference between the structured group and controls was non-significant (0.81 (0.56 to 1.17)). Static balance on an eight level hierarchy scale, ankle strength, function, and participation were significantly better in the LiFE group than in controls. LiFE and structured groups had a significant and moderate improvement in dynamic balance, compared with controls. CONCLUSIONS: The LiFE programme provides an alternative to traditional exercise to consider for fall prevention. Functional based exercise should be a focus for interventions to protect older, high risk people from falling and to improve and maintain functional capacity. TRIAL REGISTRATION: Australia and New Zealand Clinical Trials Registry 12606000025538.  
  Call Number Serial 404  
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Author Prince, A. file  url
openurl 
  Title The bitter taste of infection Type Journal Article
  Year 2012 Publication The Journal of Clinical Investigation Abbreviated Journal J Clin Invest  
  Volume 122 Issue 11 Pages (down) 3847-3849  
  Keywords Female; Genetic Predisposition to Disease; Humans; Male; Nasal Mucosa; Paranasal Sinuses; Polymorphism, Genetic; Pseudomonas Infections; Pseudomonas aeruginosa; Receptors, G-Protein-Coupled; Rhinitis  
  Abstract The human innate immune response to pathogens is complex, and it has been difficult to establish the contribution of epithelial signaling in the prevention of upper respiratory tract infection. The prevalence of chronic sinusitis in the absence of systemic immune defects indicates that there may be local defects in innate immunity associated with such mucosal infections. In this issue of the JCI, Cohen and colleagues investigate the role of the bitter taste receptors in airway epithelial cells, and find that these are critical to sensing the presence of invading pathogens.  
  Call Number Serial 543  
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Author Batchu, H.; Batra, S. file  url
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  Title Versatile Synthesis of 2-(Substituted phenyl)-6,7-dihydro-1H-indol-4(5H)-ones from Morita-Baylis-Hillman Acetates of 2-Oxo-2-(substituted phenyl)acetaldehyde Type Journal Article
  Year 2012 Publication European Journal of Organic Chemistry Abbreviated Journal Eur. J. Org. Chem.  
  Volume 2012 Issue 15 Pages (down) 2935-2944  
  Keywords Nitrogen Heterocycles; Synthetic Methods; Indole Derivatives; Morita–Baylis–Hillman  
  Abstract A versatile synthesis of 2-(substituted phenyl)-6,7-dihydro-1H-indol-4(5H)-ones from adducts of the Morita–Baylis–Hillman reaction between 2-oxo-2-(substituted phenyl)acetaldehydes and cyclohex-2-enone under mild conditions is described.  
  Call Number Serial 910  
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Author Metcalfe, R.S.; Babraj, J.A.; Fawkner, S.G.; Vollaard, N.B.J. file  url
openurl 
  Title Towards the minimal amount of exercise for improving metabolic health: beneficial effects of reduced-exertion high-intensity interval training Type Journal Article
  Year 2012 Publication European Journal of Applied Physiology Abbreviated Journal Eur J Appl Physiol  
  Volume 112 Issue 7 Pages (down) 2767-2775  
  Keywords  
  Abstract High-intensity interval training (HIT) has been proposed as a time-efficient alternative to traditional cardiorespiratory exercise training, but is very fatiguing. In this study, we investigated the effects of a reduced-exertion HIT (REHIT) exercise intervention on insulin sensitivity and aerobic capacity. Twenty-nine healthy but sedentary young men and women were randomly assigned to the REHIT intervention (men, n = 7; women, n = 8) or a control group (men, n = 6; women, n = 8). Subjects assigned to the control groups maintained their normal sedentary lifestyle, whilst subjects in the training groups completed three exercise sessions per week for 6 weeks. The 10-min exercise sessions consisted of low-intensity cycling (60 W) and one (first session) or two (all other sessions) brief 'all-out' sprints (10 s in week 1, 15 s in weeks 2-3 and 20 s in the final 3 weeks). Aerobic capacity ([Formula: see text]) and the glucose and insulin response to a 75-g glucose load (OGTT) were determined before and 3 days after the exercise program. Despite relatively low ratings of perceived exertion (RPE 13 +/- 1), insulin sensitivity significantly increased by 28% in the male training group following the REHIT intervention (P < 0.05). [Formula: see text] increased in the male training (+15%) and female training (+12%) groups (P < 0.01). In conclusion we show that a novel, feasible exercise intervention can improve metabolic health and aerobic capacity. REHIT may offer a genuinely time-efficient alternative to HIT and conventional cardiorespiratory exercise training for improving risk factors of T2D.

Subject headings: Adult; Exercise Tolerance/*physiology; Female; Humans; Insulin/*blood; Insulin Resistance/*physiology; Male; Oxygen Consumption/*physiology; Physical Exertion/*physiology; Physical Fitness/*physiology; Young Adult
 
  Call Number Serial 2268  
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Author Stirling, I.; Derocher, A.E. file  url
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  Title Effects of climate warming on polar bears: a review of the evidence Type Journal Article
  Year 2012 Publication Global Change Biology Abbreviated Journal Glob Chang Biol  
  Volume 18 Issue 9 Pages (down) 2694-2706  
  Keywords Arctic; Climate warming; Habitat loss; Polar bear; Sea ice  
  Abstract Climate warming is causing unidirectional changes to annual patterns of sea ice distribution, structure, and freeze-up. We summarize evidence that documents how loss of sea ice, the primary habitat of polar bears (Ursus maritimus), negatively affects their long-term survival. To maintain viable subpopulations, polar bears depend on sea ice as a platform from which to hunt seals for long enough each year to accumulate sufficient energy (fat) to survive periods when seals are unavailable. Less time to access to prey, because of progressively earlier breakup in spring, when newly weaned ringed seal (Pusa hispida) young are available, results in longer periods of fasting, lower body condition, decreased access to denning areas, fewer and smaller cubs, lower survival of cubs as well as bears of other age classes and, finally, subpopulation decline toward eventual extirpation. The chronology of climate-driven changes will vary between subpopulations, with quantifiable negative effects being documented first in the more southerly subpopulations, such as those in Hudson Bay or the southern Beaufort Sea. As the bears' body condition declines, more seek alternate food resources so the frequency of conflicts between bears and humans increases. In the most northerly areas, thick multiyear ice, through which little light penetrates to stimulate biological growth on the underside, will be replaced by annual ice, which facilitates greater productivity and may create habitat more favorable to polar bears over continental shelf areas in the short term. If the climate continues to warm and eliminate sea ice as predicted, polar bears will largely disappear from the southern portions of their range by mid-century. They may persist in the northern Canadian Arctic Islands and northern Greenland for the foreseeable future, but their long-term viability, with a much reduced global population size in a remnant of their former range, is uncertain.  
  Call Number Serial 480  
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