Theory and Application of the Chapman Heartbar Horseshoe for Laminitis

In the past fifteen years great advances have been made in understanding the pathogenesis and treatment of laminitis. One of these advances is the use of the heartbar shoe. In theory the Chapman heart bar should work well for the treatment of laminitis, however, in practice favorable results depend on the proper application of the shoe along with supportive care of the foot

Atmospheric fates of Criegee intermediates in the ozonolysis of isoprene

We use a large laboratory, modeling, and field dataset to investigate the isoprene + O_3 reaction, with the goal of better understanding the fates of the C_1 and C_4 Criegee intermediates in the atmosphere. Although ozonolysis can produce several distinct Criegee intermediates, the C_1 stabilized Criegee (CH_2OO, 61 ± 9%) is the only one observed to react bimolecularly. We suggest that the C_4 Criegees have a low stabilization fraction and propose pathways for their decomposition. Both prompt and non-prompt reactions are important in the production of OH (28% ± 5%) and formaldehyde (81% ± 16%). The yields of unimolecular products (OH, formaldehyde, methacrolein (42 ± 6%) and methyl vinyl ketone (18 ± 6%)) are fairly insensitive to water, i.e., changes in yields in response to water vapor (≤4% absolute) are within the error of the analysis. We propose a comprehensive reaction mechanism that can be incorporated into atmospheric models, which reproduces laboratory data over a wide range of relative humidities. The mechanism proposes that CH_2OO + H_2O (k_((H_2O)) ∼ 1 × 10^(−15) cm^3 molec^(−1) s^(−1)) yields 73% hydroxymethyl hydroperoxide (HMHP), 6% formaldehyde + H_2O_2, and 21% formic acid + H_2O; and CH_2OO + (H_2O)_2 (k_((H_2O)_2) ∼ 1 × 10^(−12) cm^3 molec^(−1) s^(−1)) yields 40% HMHP, 6% formaldehyde + H_2O_2, and 54% formic acid + H_2O. Competitive rate determinations (k_(SO_2/k(H_2O)n=1,2) ∼ 2.2 (±0.3) × 10^4) and field observations suggest that water vapor is a sink for greater than 98% of CH2OO in a Southeastern US forest, even during pollution episodes ([SO_2] ∼ 10 ppb). The importance of the CH_2OO + (H_2O)n reaction is demonstrated by high HMHP mixing ratios observed over the forest canopy. We find that CH_2OO does not substantially affect the lifetime of SO_2 or HCOOH in the Southeast US, e.g., CH_2OO + SO_2 reaction is a minor contribution (<6%) to sulfate formation. Extrapolating, these results imply that sulfate production by stabilized Criegees is likely unimportant in regions dominated by the reactivity of ozone with isoprene. In contrast, hydroperoxide, organic acid, and formaldehyde formation from isoprene ozonolysis in those areas may be significant

U.S. Billion-ton Update: Biomass Supply for a Bioenergy and Bioproducts Industry

The Report, Biomass as Feedstock for a Bioenergy and Bioproducts Industry: The Technical Feasibility of a Billion-Ton Annual Supply (generally referred to as the Billion-Ton Study or 2005 BTS), was an estimate of “potential” biomass within the contiguous United States based on numerous assumptions about current and future inventory and production capacity, availability, and technology. In the 2005 BTS, a strategic analysis was undertaken to determine if U.S. agriculture and forest resources have the capability to potentially produce at least one billion dry tons of biomass annually, in a sustainable manner—enough to displace approximately 30% of the country’s present petroleum consumption. To ensure reasonable confidence in the study results, an effort was made to use relatively conservative assumptions. However, for both agriculture and forestry, the resource potential was not restricted by price. That is, all identified biomass was potentially available, even though some potential feedstock would more than likely be too expensive to actually be economically available. In addition to updating the 2005 study, this report attempts to address a number of its shortcoming

Testing Atmospheric Oxidation in an Alabama Forest

The chemical species emitted by forests create complex atmospheric oxidation chemistry and influence global atmospheric oxidation capacity and climate. The Southern Oxidant and Aerosol Study (SOAS) provided an opportunity to test the oxidation chemistry in a forest where isoprene is the dominant biogenic volatile organic compound. Hydroxyl (OH) and hydroperoxyl (HO_2) radicals were two of the hundreds of atmospheric chemical species measured, as was OH reactivity (the inverse of the OH lifetime). OH was measured by laser-induced fluorescence (LIF) and by taking the difference in signals without and with an OH scavenger that was added just outside the instrument’s pinhole inlet. To test whether the chemistry at SOAS can be simulated by current model mechanisms, OH and HO_2 were evaluated with a box model using two chemical mechanisms: Master Chemical Mechanism, version 3.2 (MCMv3.2), augmented with explicit isoprene chemistry and MCMv3.3.1. Measured and modeled OH peak at about 10^6 cm^(−3) and agree well within combined uncertainties. Measured and modeled HO_2 peak at about 27 pptv and also agree well within combined uncertainties. Median OH reactivity cycled between about 11 s^(−1) at dawn and about 26 s^(−1) during midafternoon. A good test of the oxidation chemistry is the balance between OH production and loss rates using measurements; this balance was observed to within uncertainties. These SOAS results provide strong evidence that the current isoprene mechanisms are consistent with measured OH and HO_2 and, thus, capture significant aspects of the atmospheric oxidation chemistry in this isoprene-rich forest

CMS physics technical design report : Addendum on high density QCD with heavy ions

Peer reviewe

Dry matter losses and methane emissions during wood chip storage: the impact on full life cycle greenhouse gas savings of short rotation coppice willow for heat

A life cycle assessment (LCA) approach was used to examine the greenhouse gas (GHG) emissions and energy balance of short rotation coppice (SRC) willow for heat production. The modelled supply chain includes cutting multiplication, site establishment, maintenance, harvesting, storage, transport and combustion. The relative impacts of dry matter losses and methane emissions from chip storage were examined from a LCA perspective, comparing the GHG emissions from the SRC supply chain with those of natural gas for heat generation. The results show that SRC generally provides very high GHG emission savings of over 90 %. The LCA model estimates that a 1, 10 and 20 % loss of dry matter during storage causes a 1, 6 and 11 % increase in GHG emissions per MWh. The GHG emission results are extremely sensitive to emissions of methane from the wood chip stack: If 1 % of the carbon within the stack undergoes anaerobic decomposition to methane, then the GHG emissions per MWh are tripled. There are some uncertainties in the LCA results, regarding the true formation of methane in wood chip stacks, non-CO2 emissions from combustion, N2O emissions from leaf fall and the extent of carbon sequestered under the crop, and these all contribute a large proportion of the life cycle GHG emissions from cultivation of the cro

Immunogenicity of RNA Replicons Encoding HIV Env Immunogens Designed for Self-Assembly into Nanoparticles

Self-replicating RNAs derived from alphaviruses have high potential for vaccine applications. Utilizing lipid nanoparticle-formulated RNA replicons as a vaccine platform to deliver self-assembling protein immunogens, Melo et al. demonstrate robust anti-HIV Env antibody production and significantly improved antigen-specific B cell activation in vaccinated mice when compared with protein immunization.NIAID (Awards UM1AI100663, AI104715, EB025854 and AI048240)National Cancer Institute (Grant P30-CA14051

Testing atmospheric oxidation in an Alabama forest

The chemical species emitted by forests create complex atmospheric oxidation chemistry and influence global atmospheric oxidation capacity and climate. The Southern Oxidant and Aerosol Study (SOAS) provided an opportunity to test the oxidation chemistry in a forest where isoprene is the dominant biogenic volatile organic compound. Hydroxyl (OH) and hydroperoxyl (HO2) radicals were two of the hundreds of atmospheric chemical species measured, as was OH reactivity (the inverse of the OH lifetime). OH was measured by laser-induced fluorescence (LIF) and by taking the difference in signals without and with an OH scavenger that was added just outside the instrument's pinhole inlet. To test whether the chemistry at SOAS can be simulated by current model mechanisms, OH and HO2 were evaluated with a box model using two chemical mechanisms: Master Chemical Mechanism, version 3.2 (MCMv3.2), augmented with explicit isoprene chemistry and MCMv3.3.1. Measured and modeled OH peak at about 106 cm-3 and agree well within combined uncertainties. Measured and modeled HO2 peak at about 27 pptv and also agree well within combined uncertainties. Median OH reactivity cycled between about 11 s-1 at dawn and about 26 s-1 during midafternoon. A good test of the oxidation chemistry is the balance between OH production and loss rates using measurements; this balance was observed to within uncertainties. These SOAS results provide strong evidence that the current isoprene mechanisms are consistent with measured OH and HO2 and, thus, capture significant aspects of the atmospheric oxidation chemistry in this isoprene-rich forest