Search results for "synthesis"
showing 10 items of 2844 documents
Optimum design of two-level MCML gates
2008
In this paper, we address the problem of the optimum design of two-level MOS Current Mode Logic (MCML) gates. In particular, we describe a design methodology based on the concept of crossing-point current already introduced for the optimum design of single-level MCML gates. This methodology is suited both for automated implementation and graphic estimate of the optimum design. Moreover, it clearly shows how some important design parameters affect the optimum values of delay and power consumption. Several gates were designed in an IBM 130 nm CMOS technology. The results of SPICE simulations, reported here, demonstrate the effectiveness of the proposed design methodology.
Preparation of photocatalysts by chemical methodologies
2021
Abstract The synthesis of photocatalytic materials is an important task for obtaining better results in terms of activity and/or selectivity in photocatalysis. This chapter reports an overview of the main methodologies using physical techniques to obtain bulky, supported powders or films and coatings to be used as heterogeneous photocatalysts. The classical chemical methodologies for the preparation of photocatalytic materials are presented in the previous chapter, so the information presented here complements the aforementioned one. Materials scientists and engineers have made significant progresses in the improvement of methods of synthesis of nanomaterial solids by developing different a…
Electro-organic synthesis – a 21st century technique
2020
The severe limitations of fossil fuels and finite resources influence the scientific community to reconsider chemical synthesis and establish sustainable techniques. Several promising methods have emerged, and electro-organic conversion has attracted particular attention from international academia and industry as an environmentally benign and cost-effective technique. The easy application, precise control, and safe conversion of substrates with intermediates only accessible by this method reveal novel pathways in synthetic organic chemistry. The popularity of electricity as a reagent is accompanied by the feasible conversion of bio-based feedstocks to limit the carbon footprint. Several mi…
Ethylene-biosynthesis in conifers: Investigations on the emission of ethylene and the content of ACC and MACC in Norway Spruce (Picea abies) and silv…
1998
Abstract The assessment of forest damage is carried out throughout the European Community by evaluation of the loss and yellowing of leaves or needles. The results of this ocular damage diagnosis can be confirmed and stated more precisely by applying biochemical criteria, e.g. by monitoring ethylene, its precursor ACC (1-amino-cyclopropane-carboxylate) and the malonyl conjugate of ACC malonyl-amino-cyclopropane-carboxylate (MACC). Therefore we investigated ethylene emissions well as ACC and MACC contents in six Norway Spruce trees (Picea abies) each of eleven permanently monitored sites in the southwest of Germany. The same examinations were applied with silver fir at two additional sites. …
A parsimonious dynamic model for river water quality assessment
2010
Water quality modelling is of crucial importance for the assessment of physical, chemical, and biological changes in water bodies. Mathematical approaches to water modelling have become more prevalent over recent years. Different model types ranging from detailed physical models to simplified conceptual models are available. Actually, a possible middle ground between detailed and simplified models may be parsimonious models that represent the simplest approach that fits the application. The appropriate modelling approach depends on the research goal as well as on data available for correct model application. When there is inadequate data, it is mandatory to focus on a simple river water qua…
Trimeprazine is enantioselectively degraded by an activated sludge in ready biodegradability test conditions
2018
[EN] A great number of available pharmaceuticals are chiral compounds. Although they are usually manufactured as racemic mixtures, they can be enantioselectively biodegraded as a result of microbial processes. In this paper, a biodegradability assay in similar conditions to those recommended in OECD tests of enantiomers of trimeprazine (a phenothiazine employed as a racemate) is carried out. Experiments were performed in batch mode using a minimal salts medium inoculated with an activated sludge (collected from a Valencian Waste Water Treatment Plant, WWTP) and supplemented with the racemate. The concentration of the enantiomers of trimeprazine were monitored by means of a chiral HPLC metho…
Biochemical indicators for novel forest decline in spruce
1998
Abstract The impact of air pollution on 24 stands of spruce trees in several regions in Germany was investigated. We looked for evidence of biochemical and physiological change at the level of the photosynthetic thylakoid membranes as well as for changes in the antioxidative system in two year old needles. We observed that, as the chlorophyll content decreases in the needles, the amoung of D1 protein declines far more rapidly in relation to the redox components P700 and cytochrome f. Consequently, the PSII/PSI stoichiometry keeps dropping to pregressively lower, meaning unfavorable, values at the chlorophyll content diminishes. This is particularly the case in the higher elevation character…
Iron-based metal-organic framework: Synthesis, structure and current technologies for water reclamation with deep insight into framework integrity.
2021
Water is a supreme requirement for the existence of life, the contamination from the point and non-point sources are creating a great threat to the water ecosystem. Advance tools and techniques are required to restore the water quality and metal-organic framework (MOFs) with a tunable porous structure, striking physical and chemical properties are an excellent candidate for it. Fe-based MOFs, which developed rapidly in recent years, are foreseen as most promising to overcome the disadvantages of traditional water depolluting practices. Fe-MOFs with low toxicity and preferable stability possess excellent performance potential for almost all water remedying techniques in contrast to other MOF…
Effects of Indole-3-Carbinol and Flavonoids Administered Separately and in Combination on Nitric Oxide Production and iNOS Expression in Rats
2010
Beneficial effects of natural compounds are often attributed to modulation of NO production; however effects produced by plant extracts do not correlate with effects of purified components. The goal of our work was to study ability of flavonoids and indole-3-carbinol, as well as their combinations to modify NO production, iNOS gene and protein expression in rat tissues. Baicalein and luteolin decreased NO concentration in both intact and LPS-treated animals. Baicalein decreased iNOS gene expression. Luteolin decreased NO production in the liver and heart and number of iNOS-positive cells in the liver of LPS-treated animals. Combination of the two substances did not decrease the NO synthesis…
Microwave-assisted synthesis of PHEA-oligoamine copolymers as potential gene delivery systems
2009
Aims - Copolymers bearing oligoamines and having buffering capacity in the endosomal pH range seems very promising as non viral vectors in gene delivery, due to the great importance of endosomal escaping for an efficient endocellular DNA release. Aim of this paper was to prepare new copolymers based on α,β-poly-(N-2-hydroxyethyl)-D,L-aspartamide (PHEA) as polymeric backbone and bearing an oligoamine, such as diethylentriamine (DETA) in the side chain and useful for gene delivery. Moreover in order to reduce solvent volume and to make faster the reaction, microwave-assisted has been used. Materials and methods - PHEA copolymers bearing different amount of DETA were prepared by using bis(4-ni…