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Efficient Process (efficient + process)
Selected AbstractsEnvironmentally Friendly and Efficient Process for the Preparation of ,-Hydroxyl Ketones.CHEMINFORM, Issue 23 2004Guan-Wu Wang Abstract For Abstract see ChemInform Abstract in Full Text. [source] ChemInform Abstract: An Efficient Process for the Synthesis of ,-Arylbutanals via Copper-Mediated Grignard Coupling.CHEMINFORM, Issue 42 2001William T. Monte Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Practical and Efficient Processes for the Preparation of 4-(4-Aminophenyl)morpholin-3-ones on a Larger Scale: Precursor of Factor Xa Inhibitors.CHEMINFORM, Issue 24 2008Werner W. K. R. Mederski Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Tafoni development in a cryotic environment: an example from Northern Victoria Land, AntarcticaEARTH SURFACE PROCESSES AND LANDFORMS, Issue 10 2008Andrea Strini Abstract Tafoni are a type of cavernous weathering widespread around the world. Despite the extensive distribution of the tafoni, their genesis is not clear and is still a matter of debate, also because they occur in such different climatic conditions and on so many different types of substrate. Geomorphological characterization of more than 60 tafoni in three different Antarctic sites (two coastal and one inland) between 74 and 76° S with sampling of weathering products and salt occurrences are described together with thermal data (on different surfaces) and wind speed recorded in different periods of the year in a selected tafone close to the Italian Antarctic station. The aim of this present study is to provide further information to help understand the processes involved in the growth of tafoni in a cryotic environment, and the relationship of these processes to climate, with particular attention to the thermal regime and the role of wind. The new data presented in this paper suggest that there is no single key factor that drives the tafoni development, although thermal stress seems the most efficient process, particularly if we consider the short-term fluctuations. The data also confirm that other thermal processes, such as freezing,thawing cycles and thermal shock, are not really effective for the development of tafoni in this area. The wind speed measured within the tafoni is half that recorded outside, thus favouring snow accumulation within the tafoni and therefore promoting salt crystallization. On the other hand, the wind effect on the thermal regime within the tafoni seems negligible. While both salt weathering and thermal stress appear active in this cryotic environment, these are azonal processes and are therefore active in other climatic areas where tafoni are widespread (such as the Mediterranean region). Copyright © 2007 John Wiley & Sons, Ltd. [source] Synthesis, Functionalization, and Bioconjugation of Monodisperse, Silica-Coated Gold Nanoparticles: Robust Bioprobes,ADVANCED FUNCTIONAL MATERIALS, Issue 6 2005S. H. Liu Abstract Herein, we report an efficient process for preparing monodisperse Au@SiO2 nanoparticles using homogeneous shaking and without the use of surface-coupling silane agents or large stabilizers. The resulting pure-silica surface of the Au@SiO2 nanoparticles is very important for straightforward surface functionalization with different functional groups via well-established silica surface chemistry. Subsequent covalent bioconjugation of the aldehyde-functionalized Au@SiO2 nanoparticles with various biomolecules is successfully employed to make robust nanoprobes for fast, colorimetric DNA and protein detection based on the sequence-specific hybridization properties of DNA and the specific binding affinity between proteins, respectively. [source] An examination of exergy destruction in organic Rankine cyclesINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 10 2008P. J. Mago Abstract The exergy topological method is used to present a quantitative estimation of the exergy destroyed in an organic Rankine cycle (ORC) operating on R113. A detailed roadmap of exergy flow is presented using an exergy wheel, and this visual representation clearly depicts the exergy accounting associated with each thermodynamic process. The analysis indicates that the evaporator accounts for maximum exergy destroyed in the ORC and the process responsible for this is the heat transfer across a finite temperature difference. In addition, the results confirm the thermodynamic superiority of the regenerative ORC over the basic ORC since regenerative heating helps offset a significant amount of exergy destroyed in the evaporator, thereby resulting in a thermodynamically more efficient process. Parameters such as thermodynamic influence coefficient and degree of thermodynamic perfection are identified as useful design metrics to assist exergy-based design of devices. This paper also examines the impact of operating parameters such as evaporator pressure and inlet temperature of the hot gases entering the evaporator on ORC performance. It is shown that exergy destruction decreases with increasing evaporator pressure and decreasing turbine inlet temperatures. Finally, the analysis reveals the potential of the exergy topological methodology as a robust technique to identify the magnitude of irreversibilities associated with real thermodynamic processes in practical thermal systems. Copyright © 2008 John Wiley & Sons, Ltd. [source] Composite coating of bonelike apatite particles and collagen fibers on poly L-lactic acid formed through an accelerated biomimetic coprecipitation processJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2006Yun Chen Abstract Collagen and apatite were coprecipitated as a composite coating on poly L-lactic acid (PLLA) in an accelerated biomimetic process. The incubation solution contained collagen (1 g/L) and simulated body fluid with 5 times inorganic ionic concentrations as human blood plasma. The coating formed on PLLA films and scaffolds after a 24-h incubation was characterized by using energy-dispersive X-ray spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy (SEM). It was shown that the coating contained carbonated bonelike apatite and collagen, which was similar in composition to natural bone. SEM showed a complex composite coating of submicron bonelike apatite particulates combined with collagen fibrils. It is expected that such biocomposite coating may better facilitate cell interaction and osteoconductivity. This work provided an efficient process to obtain bonelike apatite/collagen composite coating, which is potentially useful in bone tissue engineering. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006 [source] Inhibition of sulfide on the simultaneous removal of nitrate and p -cresol by a denitrifying sludgeJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 3 2008Edna R Meza-Escalante Abstract BACKGROUND: Many industrial discharges, such as those generated from petrochemical refineries, contain large amounts of sulfurous, nitrogenous and organic contaminants. Denitrification has emerged as a suitable technology for the simultaneous removal of these pollutants in a single reactor unit; however, more evidence is demanded to clarify the limitations of denitrification on the simultaneous removal of sulfide and phenolic contaminants and to optimize the biological process. The aim of this study was to evaluate the capacity of a denitrifying sludge to simultaneously convert sulfide and p -cresol via denitrification. RESULTS: Sulfide was the preferred electron donor over p -cresol, imposing a 5 h lag phase (required for complete sulfide removal) on organotrophic denitrification. Addition of sulfide (20 mg S2, L,1) to p -cresol-amended denitrifying cultures also decreased the reduction rate of nitrate and nitrite, as well as the production rate of nitrogen gas. Nitrite reduction rate was the most affected step by sulfide, decreasing from 35 to 21 mg N (g VSS d),1. A synergistic inhibitory effect of nitrate and sulfide was also observed on nitrite reduction. Despite the effects of sulfide on the respiratory rates monitored, complete removal of nitrate, sulfide and p -cresol could be achieved after 48 h of incubation. CONCLUSION: Our results suggest that simultaneous removal of sulfide and p -cresol could be achieved in denitrifying reactors, but a large hydraulic residence time may be required to sustain an efficient process due to inhibitory effects of sulfide. Copyright © 2008 Society of Chemical Industry [source] ADSORPTION CHARACTERISTICS OF CROCIN IN THE EXTRACT OF GARDENIA FRUITS (GARDENIA JASMINOIDES ELLIS) ON MACROPOROUS RESINSJOURNAL OF FOOD PROCESS ENGINEERING, Issue 1 2009BIN YANG ABSTRACT To study resin adsorptions and investigate the differences between processes in crude extracts and microfiltrates, the adsorption characteristics of crocin in the extract of Gardenia jasminoides Ellis on 10 macroporous styrene-divinylbenzene (SDVB) resins were investigated. Ground gardenia fruit was extracted with water and the crude extract was partially purified by microfiltration. The crude extract and microfiltrate were mixed with the 10 resins until the adsorption of crocin reached equilibrium on resins. The adsorption followed the pseudo-second-order kinetics closely, but the data also fitted the first-order and intraparticle diffusion models. Furthermore, the Freundlich isotherm was found suitable for describing the equilibrate adsorption data. XAD-1180, HP20, HPD-100A and AB-8 stood out as the best performing resins in terms of their adsorptive capacities and selectivities for crocin. The thermodynamics of the adsorption process was shown to be spontaneous and exothermal in nature, and controlled by physical rather than chemical mechanisms. Adsorption with SDVB resins in conjunction with microfiltration was found to be an efficient process for the purification of crocin in gardenia extract. PRACTICAL APPLICATIONS Macroporous resins have been industrially applied in the recovery and purification of some products from plant extracts. However, there is a lack of understanding of the adsorption process and many of the applications are based on empirical data rather than on predicable models. Therefore, the development of reliable mathematical models that can accurately describe and predicate experimental data of adsorption would be extremely helpful in understanding the adsorption process as well as optimizing the design of adsorption systems. [source] An efficient process for synthesizing and hydrolyzing a phosphonated methacrylate: Investigation of the adhesive and anticorrosive propertiesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 14 2008Zhor El Asri Abstract A new phosphonated methacrylate, namely dimethyl(methacryloyloxy)methyl phosphonate (MAPC1), has been synthesized using paraformaldehyde and potassium carbonate according to the Pudovik reaction. The quantitative synthesis of MAPC1 was followed by selective hydrolysis of the ester group with sodium bromide to replace NaI (imparting non-negligible ecological impact). Pure MAPC1(OH) was obtained in high yield and efficiently copolymerized with MMA. The r1 for MAPC1(OH)) and r2 (for MMA) values are 0.99 and 1.02, respectively, which indicates that the monophosphonic groups are statistically linked to the methacrylate backbone. When blended with PVDF, MMA/MAPC1(OH) copolymers show very good adhesion promoters in both dry and wet conditions and subsequently provide good anticorrosive properties. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4794,4803, 2008 [source] Threading a peptide through a peptide: Protein loops, rotaxanes, and knotsPROTEIN SCIENCE, Issue 7 2007John W. Blankenship Abstract Proteins adopt complex folds in nature that typically avoid conformations that are knotted or "threaded" through closed loops. Is this the result of fundamental barriers to folding, or have proteins simply evolved to avoid threaded conformations? Organic synthesis has been used in supramolecular chemistry to install topological links in small molecules. By following these principles, we now show that it is possible to assemble a topologically linked protein complex by threading a linear protein through a cyclic protein to form a [2]pseudo-rotaxane. Subsequent ring closure using native chemical ligation cyclizes the linear protein, forming a [2]heterocatenane. Although the kinetics of protein threading are slower than the folding kinetics of the native protein, threading appears to be a highly efficient process. [source] Cover Picture: Biotechnology Journal 5/2006BIOTECHNOLOGY JOURNAL, Issue 5 2006Article first published online: 11 MAY 200 Cover illustration: Chirality is omnipresent in nature: Many compounds contain an asymmetric center and thus can occur in two non-superimposable mirror-image forms (enantiomers). The two enantiomers of a chiral compound often have dramatically different effects, as exemplified by the thalidomid catastrophe. Therefore, only one enantiomer is needed for the production of active substances in the pharmaceutical or agricultural industry. It is an important aspect in white biotechnology, to take advantage of highly specific catalysts of (micro-) biological origin for the synthesis of enantiopure compounds. Biocatalysis indeed is a highly efficient process and an example of environmentally friendly, ,green' chemistry, requiring relatively low energy inputs, mild solvents and generating minimal byproducts. Image © Wacker. [source] Arachidonic acid-mediated cooxidation of all- trans -retinoic acid in microsomal fractions from human liverBRITISH JOURNAL OF PHARMACOLOGY, Issue 4 2000Louise Nadin The quantitative importance of prostaglandin H synthase (PGHS)-mediated cooxidation of all- trans -retinoic acid (ATRA) was evaluated in human liver microsomes (n=17) in relation to CYP-dependent ATRA 4-hydroxylation. Observed rates of ATRA cooxidation (4.6,20 pmol mg protein,1 min,1) and 4-hydroxylation (8.7,45 pmol mg protein,1 min,1) were quantitatively similar and exhibited similar individual variation (4 and 5 fold, respectively). From kinetic studies cooxidation was an efficient process in human hepatic microsomes (VmaxKm,1=0.25) compared with NADPH- and NADH-mediated 4-hydroxylation by CYP (VmaxKm,1=0.14 and 0.02, respectively). The capacity of lipid hydroperoxide metabolites of arachidonic acid to mediate ATRA oxidation was established directly, but downstream products (D, E, F and I-series prostaglandins) were inactive. cDNA-expressed CYPs supported ATRA oxidation by lipid hydroperoxides. Whereas CYPs 2C8, 2C9 and 3A4, but not CYPs 1A2 or 2E1, were effective catalysts of the NADPH-mediated reaction, cooxidation supported by 15(S)-hydroperoxyeicosatetraenoic acid was mediated by all five CYPs. The cooxidation reaction in human hepatic microsomes was inhibited by the CYP inhibitor miconazole. These findings indicate that ATRA oxidation is quantitatively significant in human liver. Lipid hydroperoxides generated by intracellular enzymes such as prostaglandin synthase and lipoxygenases are sources of activated oxygen for CYP-mediated deactivation of ATRA to polar products. British Journal of Pharmacology (2000) 131, 851,857; doi:10.1038/sj.bjp.0703579 [source] Supercritical water for environmental technologiesJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 5 2010Dr Anne Loppinet-Serani Abstract OVERVIEW: Supercritical water is a great medium in which to perform chemical reactions and to develop processes. Due to its unique thermo-physico-chemical properties, supercritical water is able to play the role of solvent of organic compounds and/or to react with them. These specific properties have been used since the 1990s to develop new technologies dedicated to the environment and energy. IMPACT: Supercritical water based technologies are innovative and efficient processes having a strong impact on society, the environment and the economy, and is termed a sustainable technology. APPLICATIONS: Three main applications for supercritical water technology are under development: (i) supercritical water oxidation (SCWO); (ii) supercritical water biomass gasification (SCBG); and (iii) hydrolysis of polymers in supercritical water (HPSCW) for composites/plastics recycling. In this paper some fundamentals of supercritical water are first presented to introduce the above three major developments. Then these technologies are reviewed in terms of their present and future industrial development and their impact on the environment and on energy production. Copyright © 2010 Society of Chemical Industry [source] | |||||||||||||