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11.
12.
El-Temtamy S. A. Khalil S. A. Nour-El-Din A. A. Gaber A. 《Applied microbiology and biotechnology》1984,19(6):376-381
Summary Liquid-phase volumetric oxygen transfer coefficients were evaluated in a bubble column containing yeast suspensions, using the instationary oxygen absorption method and a polarographic oxygen electrode. The electrode time lag was found to be independent of both the system studied and the operating conditions. The volumetric oxygen mass transfer coefficients k
L
a could be reasonably predicted by calculating k
L from the equation derived by Bhavaraju et al. or the empirical equation of Calderbank and Moo-Young and a from the experimental gas hold-up values.Nomenclature
a
Exponent in Eq.6 or specific gas-liquid interfacial area based on reactor volume m
-
b
Exponent in Eq. 6
-
C
Constant in Eq 6 or oxygen concentration in the liquid phase g/ml
-
C
*
Equilibrium oxygen concentration g/ml
-
C
0
Oxygen concentration in the liquid phase at t=0 g/ml
-
C
E
Oxygen concentration as determined by the polarographic electrode g/ml
-
D
B
Bubble equivalent diameter mm
-
D
l
Oxygen diffusivity in the liquid phase m2/s
-
g
Acceleration of gravity m/s2
-
K
Consistency index Pasn
-
K
L
Liquid-phase mass transfer coefficient m/s
-
n
Power law exponent
-
Pe
sw
Peclet number based on bubble swarm velocity
-
S
C
Schmidt number
-
Sh
Sherwood number
-
i
Time s
-
U
B
Bubble rise velocity in infinite medium m/s
-
U
g
Superficial air velocity based on column cross-sectional area m/s
-
U
sw
Bubble swarm velocity defined by Eq.15 m/s
-
Y
MSW
Mass transfer coeficient correction factor for mobile interfaces in pseudo-plastic fluids Eq. 7
-
Y
MSW
Mass transfer coefficient correction factor for immobile interface in pseudo-plastic fluids Eq. 8
Greek letters
l
Density of liquid g/ml
- sus
Density of unaerated suspension g/ml
- wet cell
Density of yeast wet cells g/ml
-
l
Viscosity of the liquid Pas
- app
Apparent viscosity of power law fluid Pas
-
E
Electrode time lag s
-
l
Time lag due to resistance of the gas-liquid interface
s
-
g
Gas hold-up, volume fraction occupied by the gas phase
-
l
Liquid hold-up
-
c
Wet cell volume fraction 相似文献
13.
N. Kiger J. Schulz A. Khalil B. Caillou G. Mathé 《Cancer immunology, immunotherapy : CII》1978,5(3):207-210
Summary Sera from mice treated i.v. with 1 mg BCG, followed 14 days later by 0.1 ml (108 killed organisms) of Pseudomonas aeruginosa have shown the capacity to induce tumor necrosis when injected into mice bearing subcutaneous transplants either of a methyl-cholanthrene-induced sarcoma or of the P815 mastocytoma. Furthermore, immunotherapeutic trials were performed in mice bearing a subcutaneous transplanted sarcoma by combining BCG and low doses (0.01 to 0.05 ml) of Pseudomonas. Tumor necrosis was detectable 24 hours later only in the group treated by both BCG and Pseudomonas. In this group, we have also observed a significant decrease of tumor size in comparison with the groups of mice receiving BCG or Pseudomonas alone or no treatment. 相似文献
14.
The Nile catfish, Clarias lazera was found to concentrate radioactive cesium-134 and cobalt-6o from the aquatic environment. For cesium-134 the rate of uptake increased by increase of exposure time, while for cobalt-6o maximum uptake occurred after one day of exposure. The corresponding concentration factors at maximum uptake levels were 0.37 and 0.36 for cesium and cobalt respectively.The internal distribution of these radionuclides in the different tissues and organs of the fish due to uptake from the aquatic environment followed the decreasing order:For 134Cs: muscle, bone, gills, stomach, kidneys, intestine and liver.For 60Co: bone, muscle, gills, intestine, kidneys, stomach and liver.The internal distribution due to ingestion of these radionuclides followed nearly the same order as was found in case of uptake from the aquatic environment. 相似文献
15.
From the mycelium of Penicillium cyclopium a biologically active fraction (P-factor) was isolated, which increases conidiation and the formation of the benzodiazepine alkaloids cyclopenin and cyclopenol. Its activity was determined by measuring the increase of alkaloid formation in strain SM 72. On a preparative scale P-factor preparations were obtained from fermenter-grown hyphae of mutant dev 63 by extraction with water at 120°. P-factor is strongly hydrophilic but it is not a protein. It was active if added during conidiospore germination and early growth phase, causing an acceleration of protein biosynthesis. The action on alkaloid biosynthesis and sporulation is indirect and resembles that of a developmental hormone. 相似文献
16.
In the infested skin of tick-resistant guinea pigs, indirect immunofluorescence techniques have revealed that antigens from the ticks' salivary glands are associated with discrete dendritic cells in the epidermis. Evidence is presented to support the suggestion that these antigen-retaining cells are Langerhans cells. 相似文献
17.
The sugarbeet cultivar Kaumera was found to be highly susceptible to infection by the root-rot pathogens Rhizoctonia solani and Sclerotium rolfsii in the absence of salinity stress. Under this environmental condition, R. solani was more efficient than S. rolfsii in producing cell wall-degrading enzymes in infected hypocotyls. Xylanase and galactanase were most effective. The rate of cell wall degradation by R. solani was nearly 2.5 times that of S. rolfsii when cells walls of healthy hypocotyls were used as sole carbon substrate for the in vitro produced crude enzymes.Under salinity stress the pathogenicity and the performance of cell wall-degrading enzymes of R. solani and S. rolfsii varied profoundly. Pathogenicity studies showed that R. solani appeared to be more tolerant than S. rolfsii of the salinity stresses applied, and relatively more virulent to cv Kaumera. The activities of cell wall enzymes of R. solani decreased and those of S. rolfsii increased with increased salt concentration when cell wall material was used as a sole carbon source. The metabolic products produced under salinity stress by R. solani and R. solani in the cell wall amended culture media shifted the initial pH towards neutrality or slight alkalinity for R. solani and to high acidity for S. rolfsii.When model substrates were used, xyland and galactan were the most responsive substrates for degradation by the cell wall enzymes of the two fungi studied. The rate of degradation was higher for S. rolfsii than for R. solani. The excessive acidity in salt stressed S. rolfsii culture media suggested reduced activities of the enzymes involved in cell wall degradation in vivo. This may explain the decreased virulence potentialities. 相似文献
18.
O S Khalil T F Zurek C Pepe K Genger D G Huff C Coleman C Hanna R Hu J Mackowiack L Bennett 《Analytical biochemistry》1991,196(1):61-68
We describe an apparatus for measuring signals emanated from two heterogeneous chemiluminescence immunoassay (CLIA) configurations: antibody-coated polystyrene beads, in reaction tray wells, and microparticles captured by a porous matrix. An optics and fluidics design which allows the use of a common detection head for these two different assay configurations is described. The detection head moves along three Cartesian coordinates to create a localized light-tight compartment around each individual disposable reaction vessel. Reproducibility of the light seal, trigger solution delivery, and mixing is achieved for acridinium-labeled CLIA. The coated polystyrene beads configuration is tested using beta HCG, CEA, and TSH assays. The microparticle-capture configuration is tested using beta HCG and HBsAg assays. The microparticle capture CLIA has shorter incubation times and the potential for ease of automation. 相似文献
19.
Khalil Ahmed Alan T. Davis Said A. Goueli Michael J. Wilson 《Biochemical and biophysical research communications》1980,96(1):326-332
32P-labelled chromatin proteins from rat liver and ventral prostate were fractionated according to the procedure designed to enrich high-mobility-group (HMG) nonhistone proteins. This fraction, however, reproducibly demonstrated small amounts of apparently basic nonhistone proteins other than HMG nonhistone proteins. These proteins appeared to be tissue specific and were highly labelled with 32P. The 32P-labelled phosphoproteins were soluble in trichloroacetic or perchloric acid, migrated in acid-urea polyacrylamide gels, and demonstrated pI values ranging from 6.8 to 7.5. The HMG proteins 1 and 2 showed no incorporation of radioactivity under these experimental conditions. 相似文献
20.
Protein phosphokinase activity of rat liver nuclear membrane 总被引:3,自引:0,他引:3
The presence of protein phosphokinase activity in a purified nuclear-membrane preparation from adult rat liver was demonstrated by measuring the incorporation of 32P from γ-32P-ATP into endogenous nuclear-membrane proteins as well as into the exogenous protein substrates, dephosphophosvitin (DPV) and lysine-rich histone (LRH). The activity of this enzyme toward DPV was 60 times greater than that toward LRH. cAMP and cGMP did not appear to affect the phosphorylation of endogenous-membrane proteins. 相似文献