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41.
Warren L. Baker 《Journal of the Institute of Brewing》1991,97(6):457-462
An enzymic method has been developed for analysis of glucose. Glucose oxidase acts on glucose to produce hydrogen peroxide which acts to directly reduce the green Cu(II) 2–2′-bicinchoninate complex to a violet complex without horseradish peroxidase. A concentration range of 20–200 μM glucose was used but the reaction shows a linear range of 20–800 μM glucose. Interference is controlled by using a blank determination which has not been treated with glucose oxidase. The reaction has been used to estimate glucose levels in Saccharomyces cerevisiae fermentation and α-amylase, invertase and β-galactosidase reactions and coloured corn-steep fermentation media. 相似文献
42.
Sergej Gamburzev Plamen Atanasov Ebtisam Wilkins 《Sensors and actuators. B, Chemical》1996,30(3):179-183
A potentially implantable glucose biosensor for continuous monitoring of glucose levels in diabetic patients has been developed. The glucose biosensor is based on an amperometric oxygen electrode and glucose oxidase immobilized on carbon powder held in the form of a liquid suspension. The enzyme material can be replaced (the sensor recharged) without sensor disassembly. Diffusion membranes made of silastic coatings over a microporous polycarbonate membrane are used. Calibration curves of the sensors in phosphate buffer solution and in undiluted blood plasma at body temperature have been obtained. The reproducibility of the sensor response in serum at body temperature is demonstrated. The sensors have a stable signal during storage and continuous operation at body temperature for a period of at least one month. 相似文献
43.
The rate of anaerobic glucose fermentation by baker's yeast is found to be altered when tap water is replaced with "levitated" (i.e., hydrodynamically processed) water. To analyze the effect in more detail, we developed a fermentation kinetics model that differentiates between (i) nutrient transport into the cell, (ii) the "catabolic" and (iii) the "anabolic" reactions. As a result, the levitated water affects specifically the glucose uptake kinetics, whereas the other kinetic parameters remain unchanged. Remarkably, the sign of the effect changes with the water used to prepare the culture. When levitated water is used for both the culture preparation and the fermentation, the rate constant of glucose transport is increased by (67+/-25)%, relative to ordinary tap-water. When the culture is prepared in ordinary water and only the fermentation is performed in levitated water, the rate constant of glucose transport decreased by (50+/-12)%. Three-week old levitated water has no discernable effect any more. 相似文献
44.
45.
M. Werner A. Baars F. Werner C. Eder A. Delgado 《International Journal of Thermophysics》2007,28(4):1161-1180
Molecular energy transport in aqueous sucrose and glucose solutions of different mass fractions and temperatures is investigated
up to 400 MPa, using the transient hot-wire method. The results reveal an increasing thermal conductivity with increasing
pressure and decreasing mass fraction of sugar. No significant differences between sucrose and glucose solutions were observed.
Different empirical and semi-empirical relations from the literature are discussed to describe and elucidate the behavior
of the solutions with pressure. The pressure-induced change of the thermal conductivity of sugar solutions is mainly caused
by an increase of the thermal conductivity and the decrease of molar volume of the water fraction. A simple pressure adapted
mass fraction model permits an estimation of the thermal conductivity of the investigated solutions within an uncertainty
of about 3%.
An erratum to this article can be found at 相似文献
46.
Reviews the book, Brain and psyche: The biology of the unconscious by Jonathan Winson (1985). Winson offers a "biology of the unconscious," based on his reading of psychoanalysis and his research in experimental neurophysiology. Given Winson's main area of professional activity, it is not surprising that the slant of this book is one of a neuroscientist. But Winson is no slouch in the Freud department either; he devotes 3 of 10 chapters to a well-expounded, somewhat selective, chronological account of the main events leading to the development of psychoanalytic thought. In tackling the challenge of such an integration, Brain and psyche makes a unique and valuable theoretical contribution. Many different types of experiences, along with their associated cognitive and emotional concomitants, will form relatively permanent traces in the brain and thus exert subsequent effects on behavior, by virtue of their being consolidated during critical periods. This is why, says Winson, so many patterns of behavior, adaptive or maladaptive, appear so fixed and immutable in an individual's personality. Dreams allow us to glimpse at the neurobehavioral process whereby, from early childhood on, behavioral strategies are laid down, modified, or consulted, a process that Winson calls the unconscious personality. But it is Winson's account of repression that is the most intriguing. Repression is a process that intervenes in the temporal space between the generation of an idea, emotional feeling, or sensory impression, and the subjective apperception of that experience. Winson makes the conceptual leap from experimental neurophysiology (he works mainly with the rat) to human psychodynamics. What seems to be missing is a middle step, some evidence from human brain research that could link the two domains. Winson has taken an important first step in bridging the chasm between laboratory and consulting room. What we need now is more data from the human side of the brain and behavioral sciences to bring these domains closer still. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
47.
The current dispute regarding the existence of repression has mainly focused on whether people remember or forget trauma. Repression, however, is a multidimensional construct, which, in addition to the memory aspect, consists of pathogenic effects on adjustment and the unconscious. Accordingly, in order to arrive at a more accurate decision regarding the existence of repression, studies relevant to all three areas are reviewed. Moreover, since psychoanalysis regards repression as a key factor in accounting for the development and treatment of neurotic disorders, relevant research from these two domains are also taken into account. This comprehensive evaluation reveals little empirical justification for maintaining the psychoanalytic concept of repression. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
48.
Hydrogen production and metabolic flux analysis of metabolically engineered Escherichia coli strains
Seohyoung Kim Eunhee Seol You-Kwan Oh G.Y. Wang Sunghoon Park 《International Journal of Hydrogen Energy》2009,34(17):7417-7427
Escherichia coli can produce H2 from glucose via formate hydrogen lyase (FHL). In order to improve the H2 production rate and yield, metabolically engineered E. coli strains, which included pathway alterations in their H2 production and central carbon metabolism, were developed and characterized by batch experiments and metabolic flux analysis. Deletion of hycA, a negative regulator for FHL, resulted in twofold increase of FHL activity. Deletion of two uptake hydrogenases (1 (hya) and hydrogenase 2 (hyb)) increased H2 production yield from 1.20 mol/mol glucose to 1.48 mol/mol glucose. Deletion of lactate dehydrogenase (ldhA) and fumarate reductase (frdAB) further improved the H2 yield; 1.80 mol/mol glucose under high H2 pressure or 2.11 mol/mol glucose under reduced H2 pressure. Several batch experiments at varying concentrations of glucose (2.5–10 g/L) and yeast extract (0.3 or 3.0 g/L) were conducted for the strain containing all these genetic alternations, and their carbon and energy balances were analyzed. The metabolic flux analysis revealed that deletion of ldhA and frdABdirected most of the carbons from glucose to the glycolytic pathway leading to H2 production by FHL, not to the pentose phosphate pathway. 相似文献
49.
Glucose oxidase (GOD) immobilized in nanogold particles (NAs)-N,N-dimethylformamide (DMF) composite film on glassy carbon (GC) electrode exhibits a pair of quasi-reversible and unstable peaks due to the redox of flavin adenine dinucleotide (FAD) of GOD. When ionic liquids (ILs) 1-butyl-3-methylimidazolium tetrafluoroborate (BMIMBF4) or trihexyltetradecylphosphorium bis (trifluoromethylsulfony) (P666,14 NTf2) is introduced in the film, the peaks become small. But ILs 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6) and 1-octyl-3-methylimidazolium hexafluorophate (OMIMPF6) make the peaks large and stable. In different composite films the formal potential (E0′) of GOD is different. UV-vis spectra show that the GOD dispersed in these films almost retains its native structure and there are weak interactions between ILs and GOD. Electrochemical impedance spectra display that NAs can promote the electron transfer between FAD and GC electrode; and ILs can affect the electron transfer through interacting with GOD. The thermal stability of GOD entrapped in NAs-DMF-ILs composite films is also influenced by ILs, and it follows such order as: in NAs-DMF-OMIMPF6 > in NAs-DMF-BMIMPF6 ≈ in NAs-DMF-BMIMBF4 > in NAs-DMF. In addition, GOD immobilized in NAs-DMF-OMIMPF6 and NAs-DMF-BMIMPF6 films shows good catalytic activity to the oxidation of glucose. The Imax of H2O2 and the apparent Km (Michaelis-Menten constant) for the enzymatic reaction are calculated. 相似文献
50.
Nikolaos Dimitratos Jose Antonio Lopez-Sanchez Graham J. Hutchings 《Topics in Catalysis》2009,52(3):258-268
The use of renewable feedstocks, derived from biomass, for the chemical industry is discussed. The modern chemical industry
is based around platform chemicals, e.g. ethene, propene, benzene and xylenes, which are readily derived from oil, and using
these intermediates a broad range of finished products can be derived. While it is feasible that biomass can be converted
to syngas and hence to existing key platform chemicals, this loses all of the chemical complexity that is inherent in bio-derived
molecules. In this paper some of the options are considered and, in particular, the oxidation of glucose and glycerol using
gold nanoparticles supported on carbon is described. We also contrast the oxidation of glycerol using supported gold and gold–palladium
alloys prepared using an impregnation technique, since the gold–palladium alloys have been shown to be highly effective for
the oxidation of alcohols and the synthesis of hydrogen peroxide. 相似文献