137 research outputs found
Self identified research needs of New York organic farmers
A survey of organic farmers in New York State identified problems in need of university research. Weed management was the most frequently mentioned problem by far, identified as significant by two-thirds of the organic farmers. Only a few other problems were listed as significant, including insufficient time for farm work, lack of markets, low prices, and lack of appropriate tools. These were cited by more than a third of the farmers. Drought, insect management, and a lack of a dependable supply of labor were cited by about one-third of the respondents. The survey also examined organic farmers' information sources. They do not use conventional sources of agricultural information, such as the extension service and conventional agricultural media, as much as books, magazines, and newsletters on organic f arming, other organic f armers, and on-farm experiments. Many respondents noted that local extension agents did not know very much about non-chemical solutions to organic production problems. They considered University Extension to be accessible, but not very useful in solving problems specific to organic farming, and had many suggestions to improve Land Grant research in organic agriculture
Three-dimensionally Ordered Macroporous Structure Enabled Nanothermite Membrane of Mn2O3/Al
Mn2O3 has been selected to realize nanothermite membrane for the first time in the literature. Mn2O3/Al nanothermite has been synthesized by magnetron sputtering a layer of Al film onto three-dimensionally ordered macroporous (3DOM) Mn2O3 skeleton. The energy release is significantly enhanced owing to the unusual 3DOM structure, which ensures Al and Mn2O3 to integrate compactly in nanoscale and greatly increase effective contact area. The morphology and DSC curve of the nanothermite membrane have been investigated at various aluminizing times. At the optimized aluminizing time of 30 min, energy release reaches a maximum of 2.09 kJ∙g−1, where the Al layer thickness plays a decisive role in the total energy release. This method possesses advantages of high compatibility with MEMS and can be applied to other nanothermite systems easily, which will make great contribution to little-known nanothermite research
Hypocholesterolemic effect of \u3ci\u3eNostoc commune\u3c/i\u3e var. \u3ci\u3esphaeroides\u3c/i\u3e Kützing, an edible blue-green alga
Background Intake of an edible blue-green alga Nostoc commune var. sphaeroides Kützing (N. commune) has been shown to lower plasma total cholesterol concentration, but the mechanisms behind the hypocholesterolemic effect have not been elucidated. Aim of the study To elucidate the mechanisms underlying the cholesterol-lowering effect of N. commune in mice. Methods Male C57BL/6J mice were fed the AIN-93 M diet supplemented with 0 or 5% (wt/wt) dried N. commune for 4 weeks. Lipid levels in the plasma and liver, intestinal cholesterol absorption, and fecal sterol excretion were measured. Expression of hepatic and intestinal genes involved in cholesterol metabolism was evaluated by quantitative realtime PCR. Results N. commune supplementation significantly reduced total plasma cholesterol and triglyceride concentrations by ~20% compared to controls. Intestinal cholesterol absorption was significantly decreased, while fecal neutral sterol output was significantly increased in N. commune–fed mice. mRNA levels of the cholesterol transporters such as Niemann Pick C1 Like 1, scavenger receptor class B type 1, ATP-binding cassette transporters G5 and A1 in small intestine were not significantly different between two groups. Hepatic lipid contents including total cholesterol, triglyceride and free cholesterol in N. commune–fed mice were not significantly altered. However, the expression of cholesterol-modulating genes including sterol regulatory element binding protein-2 and 3-hydroxy-3-methylglutaryl coenzyme A reductase were significantly increased in mice fed N. commune. Conclusions N. commune supplementation exerted a hypocholesterolemic effect in mice, largely in part, by reducing intestinal cholesterol absorption and promoting fecal neutral sterol excretion
Repression of Proinflammatory Gene Expression by Lipid Extract of \u3ci\u3eNostoc commune\u3c/i\u3e var \u3ci\u3esphaeroides\u3c/i\u3e Kützing, a Blue-green Alga, via Inhibition of Nuclear Factor-κB in RAW 264.7 Macrophages
We investigated whether lipid extract from a blue-green alga, N. commune, modulates proinflammatory gene expression in RAW 264.7 macrophages. The cells were incubated with N. commune lipid extract (0–100 μg/mL) and subsequently activated by LPS (100 ng/mL). Quantitative real-time PCR analysis showed that mRNA abundance of proinflammatory mediators, including TNF-α, COX-2, IL-1β, IL-6, and iNOS, was significantly reduced by N. commune lipid extract in a dose-dependent manner. Secretion of TNF-α and IL-1β into cell culture medium was also significantly decreased by N. commune lipid extract. Thin-layer chromatography-densitometry analysis showed that N. commune lipid extract contained approximately 15% of fatty acids. To determine whether the inhibition of proinflammatory mediator production by N. commune lipid extract is primarily conferred by fatty acids in the lipid extract, macrophages were incubated with 100 μg/mL of N. commune lipid extract or 15 μg/mL of a fatty acid mixture, which was formulated to reflect the fatty acid composition of N. commune lipid extract. The fatty acid mixture significantly reduced RNA abundance of TNF-α and COX-2, but to a lesser extent than did the N. commune lipid extract, suggesting the presence of additional bioactive compounds with an anti-inflammatory property in the lipid extract. As NF-κB is a major regulator for the proinflammatory gene expression, we measured its DNA-binding activity. DNA-binding activity of NF-κB was significantly reduced by N. commune lipid extract. In conclusion, our study suggests that N. commune lipid extract represses the expression of proinflammatory genes in RAW 264.7 macrophages, at least in part, by inhibiting the activation of NF-κB pathway
Adsorption and dissociation of molecular oxygen on the (0001) surface of double hexagonal close packed americium
In our continuing attempts to understand theoretically various surface
properties such as corrosion and potential catalytic activity of actinide
surfaces in the presence of environmental gases, we report here the first ab
initio study of molecular adsorption on the double hexagonal packed (dhcp)
americium (0001) surface. Dissociative adsorption is found to be energetically
more favorable compared to molecular adsorption. The most stable configuration
corresponds to a horizontal approach molecular dissociation with the oxygen
atoms occupying neighboring h3 sites, with chemisorption energies at the NSOC
and SOC theoretical levels being 9.395 eV and 9.886 eV, respectively. The
corresponding distances of the oxygen molecule from the surface and
oxygen-oxygen distance were found to be 0.953 Ang. and 3.731 Ang.,
respectively. Overall our calculations indicate that chemisorption energies in
cases with SOC are slightly more stable than the cases with NSOC in the
0.089-0.493 eV range. The work functions and net magnetic moments respectively
increased and decreased in all cases compared with the corresponding quantities
of the bare dhcp Am (0001) surface. The adsorbate-substrate interactions have
been analyzed in detail using the partial charges inside the muffin-tin
spheres, difference charge density distributions, and the local density of
states. The effects, if any, of chemisorption on the Am 5f electron
localization-delocalization characteristics in the vicinity of the Fermi level
are also discussed.Comment: 6 tables, 10 figure
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Local Structure and Vibrational Properties of α'-Pu Martensitein Ga-Stabilized δ-Pu
Extended x-ray absorption fine structure spectroscopy (EXAFS) is used to investigate the local atomic environment and vibrational properties of plutonium and gallium atoms in the {alpha}{prime} and {delta} phases of a mixed phase Pu-Ga alloy. EXAFS results measured at low temperature compare the structure of the mixed phase sample with a single-phase {delta}-Pu sample. EXAFS spectral components attributed to both {alpha}{prime}-Pu and {delta}-Pu were observed in the mixed phase sample. Ga K-edge EXAFS spectra indicate local atomic environments similar to the Pu LIII-edge EXAFS results, which suggests that Ga is substitutional for Pu atoms in both the monoclinic {alpha}{prime}-Pu and the fcc {delta}-Pu structures. In {delta}-Pu, we measure a Ga-Pu bond length contraction of 0.11 Angstroms with respect to the Pu-Pu bond length. The corresponding bond-length contraction around Ga in {alpha}{prime}-Pu is only 0.03 Angstroms. Results from temperature-dependent Pu LIII-edge EXAFS measurements are fit to a correlated Debye model, and a large difference in the Pu-Pu bond Debye temperature is observed for the {alpha}{prime} and {delta} phases: {theta}{sub cD}({alpha}{prime})=159{+-}13 K versus {theta}{sub cD}({delta})=120{+-}3 K. The corresponding analysis for the Ga K EXAFS determines a Ga-Pu bond Debye temperature of {theta}{sub cD}({delta})=188{+-}12 K in the {delta}-Pu phase. These results are related to the observed solubility of Ga in {delta}-Pu, the ''stabilization'' of {delta}-Pu by Ga at room temperature, and the insolubility of Ga in {alpha}{prime}-Pu
Interfacial Chemistry in Al/CuO Reactive Nanomaterial and Its Role in Exothermic Reaction.
Interface layers between reactive and energetic materials in nanolaminates or nanoenergetic materials are believed to play a crucial role in the properties of nanoenergetic systems. Typically, in the case of Metastable Interstitial Composite nanolaminates, the interface layer between the metal and oxide controls the onset reaction temperature, reaction kinetics, and stability at low temperature. So far, the formation of these interfacial layers is not well understood for lack of in situ characterization, leading to a poor control of important properties. We have combined in situ infrared spectroscopy and ex situ X-ray photoelectron spectroscopy, differential scanning calorimetry, and high resolution transmission electron microscopy, in conjunction with firstprinciples calculations to identify the stable configurations that can occur at the interface and determine the kinetic barriers for their formation. We find that (i) an interface layer formed during physical deposition of aluminum is composed of a mixture of Cu, O, and Al through Al penetration into CuO and constitutes a poor diffusion barrier (i.e., with spurious exothermic reactions at lower temperature), and in contrast, (ii) atomic layer deposition (ALD) of alumina layers using trimethylaluminum (TMA)produces a conformal coating that effectively prevents Al diffusion even for ultrathin layer thicknesses (∼0.5 nm), resulting in better stability at low temperature and reduced reactivity. Importantly, the initial reaction of TMA with CuO leads to the extraction of oxygen from CuO to form an amorphous interfacial layer that is an important component for superior protection properties of the interface and is responsible for the high system stability. Thus, while Al e-beam evaporation and ALD growth of an alumina layer on CuO both lead to CuO reduction, the mechanism for oxygen removal is different, directly affecting the resistance to Al diffusion. This work reveals that it is the nature of the monolayer interface between CuO and alumina/Al rather than the thickness of the alumina layer that controls the kinetics of Al diffusion, underscoring the importance of the chemical bonding at the interface in these energetic materials
Altered spin state equilibrium in the T309V mutant of cytochrome P450 2D6: a spectroscopic and computational study
Cytochrome P450 2D6 (CYP2D6) is one of the most important cytochromes P450 in humans. Resonance Raman data from the T309V mutant of CYP2D6 show that the substitution of the conserved I-helix threonine situated in the enzyme’s active site perturbs the heme spin equilibrium in favor of the six-coordinated low-spin species. A mechanistic hypothesis is introduced to explain the experimental observations, and its compatibility with the available structural and spectroscopic data is tested using quantum-mechanical density functional theory calculations on active-site models for both the CYP2D6 wild type and the T309V mutant
Characteristics of the Energetic Igniters Through Integrating Al/NiO Nanolaminates on Cr Film Bridge
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