170 research outputs found
Five and Six Coordinated Complexes of Di and Trivalent Iron with Ligands Derived from Acidhydrazides and Acetylacetone
Picolinic acid hydrazide(PH) and isonicotinic acidhydrazide
(INH) react with acetylacetone in the presence of iron(II) and iron .
(III) salts and give complexes of open chain tetradentate ligands
through a template effect. The complexes are isolated and characterised
as five and six-coordinated by the help of analyses,
conductance, molecular weight, magnetic, Mossbauer, electronic
and infrared spectral studies. Two molecules of PH or INH condense
with a single acetylacetone moiety giving open chain tetradentate
ligands. Attempts to isolate the ligand in the free state are,
however, unsuccessful. The Ac(PH)2 coordinates through azomethine
and pyridine nitrogens, while Ac(INHh does so through
azomethine nitrogens and amide oxygens. Mossbauer spectra are
consistent with their proposed geometries and reveal that iron is
in the high-spin state. Various ligand field parameters are calculated
using normalised spherical harmonic Hamiltonian theory and
the amount of distortion is calculated in terms of DT/DQ. Metal-
ligand vibrations in the far IR region are discussed
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Market penetration of new energy systems estimated by econometric and stochastic methodology
A methodology was developed to evaluate the market potential of new energy technologies and systems in today's fast changing US economic and energy environment. An econometric and stochastic model approach is used to analyze the technical, economic, and market factors influencing the possible market penetration of new energy systems. The market model methodology includes four phases: Phase I - Segment the new technology/end-use market; Phase II - Estimate the technical market; Phase III - Estimate the economic market; and Phase IV - Estimate the market penetration. The market penetration of new Integrated Community Energy Systems (ICES) was estimated by this methodology. To illustrate the methodology, highlights of the ICES application are included in this paper
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Macroeconomic impacts of clean diesel engines -- phase 2 report : U.S.-produced clean diesel engines and SIDI gasoline engines for selected light trucks.
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A desiccant/steam-injected gas-turbine industrial cogeneration system
An integrated desiccant/steam-injected gas-turbine system was evaluated as an industrial cogenerator for the production of electricity and dry, heated air for product drying applications. The desiccant can be regenerated using the heated, compressed air leaving the compressor. The wet stream leaves the regenerator at a lower temperature than when it entered the desiccant regenerator, but with little loss of energy. The wet stream returns to the combustion chamber of the gas-turbine system after preheating by exchanging heat with the turbine exhaust strewn. Therefore, the desiccant is regenerated virtually energy-free. In the proposed system, the moisture-laden air exiting the desiccant is introduced into the combustion chamber of the gas-turbine power system. This paper discusses various possible design configurations, the impact of increased moisture content on the combustion process, the pressure drop across the desiccant regenerator, and the impact of these factors on the overall performance of the integrated system. A preliminary economic analysis including estimated potential energy savings when the system is used in several drying applications, and equipment and operating costs are also presented
A computational-based update on microRNAs and their targets in barley (Hordeum vulgare L.)
<p>Abstract</p> <p>Background</p> <p>Many plant species have been investigated in the last years for the identification and characterization of the corresponding miRNAs, nevertheless extensive studies are not yet available on barley (at the time of this writing). To extend and to update information on miRNAs and their targets in barley and to identify candidate polymorphisms at miRNA target sites, the features of previously known plant miRNAs have been used to systematically search for barley miRNA homologues and targets in the publicly available ESTs database. Matching sequences have then been related to Unigene clusters on which most of this study was based.</p> <p>Results</p> <p>One hundred-fifty-six microRNA mature sequences belonging to 50 miRNA families have been found to significantly match at least one EST sequence in barley. As expected on the basis of phylogenetic relations, miRNAs putatively orthologous to those of <it>Triticum </it>are significantly over-represented inside the set of identified barley microRNA mature sequences. Many previously known and several putatively new miRNA/target pairs have been identified. When the predicted microRNA targets were grouped into functional categories, biological processes previously known to be regulated by miRNAs, such as development and response to biotic and abiotic stress, have been highlighted and most of the target molecular functions were related to transcription regulation. Candidate microRNA coding genes have been reported and genetic variation (SNPs/indels) both in functional regions of putative miRNAs (mature sequence) and at miRNA target sites has been found.</p> <p>Conclusions</p> <p>This study has provided an update of the information on barley miRNAs and their targets representing a foundation for future studies. Many of previously known plant microRNAs have homologues in barley with expected important roles during development, nutrient deprivation, biotic and abiotic stress response and other important physiological processes. Putative polymorphisms at miRNA target sites have been identified and they can represent an interesting source for the identification of functional genetic variability.</p
Chemical PARP Inhibition Enhances Growth of Arabidopsis and Reduces Anthocyanin Accumulation and the Activation of Stress Protective Mechanisms
Poly-ADP-ribose polymerase (PARP) post-translationally modifies proteins through the addition of ADP-ribose polymers, yet its role in modulating plant development and stress responses is only poorly understood. The experiments presented here address some of the gaps in our understanding of its role in stress tolerance and thereby provide new insights into tolerance mechanisms and growth. Using a combination of chemical and genetic approaches, this study characterized phenotypes associated with PARP inhibition at the physiological level. Molecular analyses including gene expression analysis, measurement of primary metabolites and redox metabolites were used to understand the underlying processes. The analysis revealed that PARP inhibition represses anthocyanin and ascorbate accumulation under stress conditions. The reduction in defense is correlated with enhanced biomass production. Even in unstressed conditions protective genes and molecules are repressed by PARP inhibition. The reduced anthocyanin production was shown to be based on the repression of transcription of key regulatory and biosynthesis genes. PARP is a key factor for understanding growth and stress responses of plants. PARP inhibition allows plants to reduce protection such as anthocyanin, ascorbate or Non-Photochemical-Quenching whilst maintaining high energy levels likely enabling the observed enhancement of biomass production under stress, opening interesting perspectives for increasing crop productivity
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