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1.
The problem of calculating the thermodynamic properties of two-dimensional semiclassical hard-body fluids is studied. Explicit expressions are given for the first-order quantum corrections to the free energy, equation of state, and virial coefficients. The numerical results are calculated for the planar hard dumbbell fluid. Significant features are the increase in quantum corrections with increasing eta and increasing L*=L/sigma(0). 相似文献
2.
Cytochrome P-450 isozymes represent a critical component of nature’s spectrum of detoxification catalysts that could be exploited
for bioremediation. The ethanol-inducible human cytochrome P-450 2E1 serves as a model eukaryotic P-450 that complements the
bacterial P-450 cam in dehalogenation and detoxification of environmental pollutants. We explored the construction of novel
chimeric P-450s using cytochrome P-450 camC and 2E1 genes. For construction of chimera 1 (478 amino acids, 55.14 kDa), 145 amino acids from the N-terminus of P-450 2E1 protein
(493 amino acids, 56.84 kDa) were replaced with 130 amino acids from the N-terminus of P-450 camC protein (415 amino acids,
46.66 kDa). In chimera 2 (525 amino acids, 60.24 kDa) the strategy involves replacement of 28 amino acids in the C-terminus
of chimera 1 with 75 amino acids from the C-terminus of P-450 camC gene. Homology models of both the chimeric proteins were
developed using SWISS-MODEL based on the known crystal structure of cytochrome P-450 camC, BM-3, 1DT6A, and 2C17A. The models
indicated that the proposed heme-binding site was intact, which is inevitable for catalytic activity of cytochrome P-450s.
The expression of chimera 1 and 2 genes in Escherichia coli DH5α was evident from light-pink cell pellets, protein band in sodium dodecyl sulfate polyacrylamide gel electrophoresis,
and diagnostic carbon monoxide-difference spectra. Our studies show that strategies can be developed to exploit the natural
diversity of the P-450 superfamily to generate chimeric biocatalysts that would provide new templates amenable to directed
evolution. 相似文献
3.
Summary The coagulation concentration for a titania sol decreases if the concentration of a mixture of electrolytes and papain decreases. If the concentration of papain is increased then lesser amount of electrolytes is needed to coagulate the sol. If glycine is added as an additional substance then the value decreases more rapidly. There is no significant change in the pH and the electrical conductance of the sol by the addition of papain or electrolytes. There is a little change, when glycine is added as an additional substance. These observations are explained due to the formation of negative papain ions in a low pH region. The possibility of the adsorption or the release of the counter ions is ruled out.The authors wish to thank Dr.R. C. Mehrotra, Professor and the Head of the Chemistry Department for providing all the facilities for this work. We are also thankful to the Ministry of Education, Government of India, for the award of a research scholarship to one of us (V.K.S.). 相似文献
4.
Development of a new method for the estimation of substituted phosphates such as dibutyl phosphate (DBP) and monobutyl phosphate (MBP) is described in this paper. The method is based on the decolouration of lanthanum-Xylenol Orange complex by DBP and MBP at pH 5. 相似文献
5.
The method for determination of chlorpyrifos is validated and dissipation behaviour of residue in scented rose and percent transfer in different products is described. GC-electron-capture detection with a HP-1, 30 m x 0.53 mm, 3.0 microm capillary column and nitrogen at 1 ml/min was used in the study. Plant matrices studied were: leaves, flowers, soil, rose water, absolute and concrete. Detector response linearity and sensitivity, limit of detection and determination, percent recovery were determined based on area response (mm2) of the standard. Analytical field and laboratory samples (rose water by hydro-distillation of the flowers, concrete and absolute by hexane extraction and condensation) were analysed for evaluation of the method. Samples were extracted with acetone, partitioned with water, saturated sodium chloride solution and dichloromethane. The organic layer was rotary-evaporated to 2 ml for cleanup with silica-carbon column. The column was eluted with dichloromethane-toluene-acetone (10:2:2, v/v/v) and the derived solution was rotary-evaporated to 5 ml for end analysis. Matrix enhancement effect was observed for leaf and soil samples for which corrective approach was followed to compensate for overestimation of the residue. Limit of detection for chlorpyrifos standard was 0.05 mg/l with good linearity of detector response (R2 = 0.99). Percent recovery ranged from 78 to 117% in different plant matrices (fortification level 1, 4 and 8 mg/l). Dissipation behaviour showed that chlorpyrifos was below detection limit by the 12th day of application on the scented rose with half life of 3.40 days on leaves and 3.10 days on flowers at 0.1% dosage. Percent transfer studies showed that 5.71, 46.91 and 38.80% of the residue from flowers was transferred to rose water, concrete and absolute, respectively. 相似文献
6.
Summary The coagulation concentration for silver iodide sol, both in presence of pyridine and dioxane, increases for mono- and bivalent
coagulating electrolyte. In presence of a mixture of pyridine and dioxane in equal volume, the coagulation concentration assumes
an intermediate value, which is nearer to dioxane. However, in presence of dioxane more bivalent electrolyte is needed than
in presence of pyridine. If a bivalent coagulating electrolyte is added to a sol containing a mixture of pyridine and dioxane,
the amount of electrolyte required to coagulate is less than pyridine and greater than dioxane. Thus silver iodide sol is
more stable toward mono- and bivalent coagulating electrolytes. The degree of stabilization increases with the decrease of
the dielectric constant of the dispersing medium. The intermediate values for dioxane pyridine mixture is accountable by the
fact that dioxane acts as a solvent for pyridine. The PH value of the sol increases up to the coagulation point. Beyond this,
there is an abrupt decrease. When the particles settle down completely a rise in PH is again noted on the further addition
of electrolytes. The increase in the electrical conductance is more significant after coagulation. These changes have been
explained by adsorption of the ions and due to the release of ions from the electrical double layer.
Our thanks are due to Prof. R. C. Mehrotra for providing all the facilities for this work and to Prof. S. Ghosh of Allahabad University for helpful discussions. Thanks are also due to the University Grants Commission, Government of India, for the award of a research scholarship to one of us (V. K. S.). 相似文献
Zusammenfassung Die Koagulationskonzentration für Silberjodidsol in Gegenwart von Pyridin und Dioxan steigt für ein- und zweiwertige Elektrolyte an. In Gegenwart einer Mischung zu gleichen Volumen erh?lt man mittlere Werte, n?her denen zu Dioxan. Für Koagulation in Gegenwart von Dioxan ist jedoch mehr zweiwertiger Elektrolyt notwendig als in Gegenwart von Pyridin. Bei Koagulation mit zweiwertigem Elektrolyt verbraucht ein Sol mit der Mischung von Pyridin und Dioxan weniger als für Pyridin und mehr als für Dioxan. Daher ist das Silbersol gegenüber ein- und zweiwertigen Elektrolyten stabiler. Der Grad der Stabilisierung w?chst mit abnehmender Dielektrizit?tskonstante des Dispersionsmediums. Die Zwischenwerte der Dioxan-Pyridin-Mischungen lassen sich verstehen durch die Tatsache, da? Dioxan als L?sungsmittel für Pyridin wirkt. Der PH-Wert des Sols w?chst bis zum Koagulationspunkt, darüberhinaus erfolgt ein steiler Abfall. Wenn die Teilchen vollst?ndig absetzen, ist bei weiterer Zugabe von Elektrolyt ein erneuter Anstieg im PH feststellbar. Der Anstieg der elektrolytischen Leitf?higkeit wird nach der Koagulation ausgepr?gter. Diese ?nderungen lassen sich durch Ionenadsorption und Freiwerden von Ionen aus der elektrischen Doppelschicht erkl?ren.
Our thanks are due to Prof. R. C. Mehrotra for providing all the facilities for this work and to Prof. S. Ghosh of Allahabad University for helpful discussions. Thanks are also due to the University Grants Commission, Government of India, for the award of a research scholarship to one of us (V. K. S.). 相似文献
7.
8.
Mandal Prashanta Kumar Seth Gauri Shanker Sarkar Subharthi Chamkha Ali 《Journal of Thermal Analysis and Calorimetry》2021,143(3):1901-1916
Journal of Thermal Analysis and Calorimetry - Numerical simulation of a non-linear mathematical model governing an arbitrarily oblique slip flow of a nanofluid, with suspended carbon nanotubes in... 相似文献
9.
10.
JPC – Journal of Planar Chromatography – Modern TLC - Flavonoids and phenolic acids with a variety of biological activity are considered to be the main compounds in propolis–a... 相似文献