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91.
Abou-Zeid A. Abou-Zeid Abd El-Wahab I. Eissa Hassan M. Salem 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1976,26(6):318-322
Production of gentamicin antibiotics by Micromonospora purpurea was carried out successfully on a synthetic medium which contained the following ingredients (g/litre): glucose 10.0, NaNO3 2.0, KH2PO4 1.0, and CaCO3 1.0. The initial pH value of the fermentation medium was adjusted to 7.2. Effects of certain amino acids, organic acids, vitamins, purine and pyrimidine bases on the fermentative production of gentamicins were revealed. The ingredients which increased the antibiotic yields were phenylalanine, isoleucine, lysine, methionine, leucine, arginine, glycine, β′-alanine, cystine, tryptophan, malic acid, maleic acid, cobalamin, folic acid, riboflavin, vitamin B1, vitamin B6, biotin, nicotinamide, uracil, adenine, guanine and adenosine. Trace elements (Co, Mo, Fe, Cu, Zn and Mn) exhibited their important role on the biosynthesis and formation of gentamicins by Micromonospora purpurea. 相似文献
92.
93.
Heat transfer from five horizontal copper plates with different surface finish to boiling refrigerants R11 (CFCI3) and R115 (C2F5Cl) was measured at saturation pressures between 0.4 and 91% of the critical pressure. Although the relative pressure dependence of the heat transfer coefficient α is similar for the plates with different surface treatment, a detailed comparison of the experimental results shows that the influence of the different surface conditions achieved by mechanical and chemical treatment on the absolute value of α cannot be correlated by one of the roughness parameters used in the literature, within the whole range of pressures investigated. 相似文献
94.
Titanium substrates were ion plated with aluminium, producing under certain conditions a graded interface 5 μm deep. The graded interface consists of a solid solution of aluminium in titanium together with TiAl3. The solid solution has a near perfect hexagonal close-packed structure and the hardness of the interface is about 850 VHN. The combination of increased hardness and modified structure results in low friction coefficients and wear rates, and the ion-plated aluminium film provides excellent corrosion resistance. Thus the method has immense practical application in preventing seizure and corrosion in aircraft fasteners. 相似文献
95.
S.A.L. Salem S.T.S. Al-Hassani W. Johnson 《International Journal of Mechanical Sciences》1975,17(3):211-225
For nail driving, some aspects of the effect on penetration of the hammer mass, the speed at impact, the nail size and section shape and the driving direction in relation to the wood grain are reported.A 6 in. long, 0·236 in. dia., round nail was strain gauged to show how the strain in the nail varies with time during an impact.An analysis, which reasonably accounts for the experimental results, is developed for predicting the strain pulse in the nail, the amount of penetration by the nail and its time under strain.Maintaining the same kinetic energy input at each blow, it is found that the larger the initial penetration, the smaller is the further penetration.The effect on penetration depth of the material backing to the piece of wood is reported.The variation of the Euler buckling load with the nail penetration for a specific type of wood and nail dimensions is given. 相似文献
96.
When the cost of reducing the duration of activities is convex and nonlinear, it may be advisable (to reduce the computing burden) to seek a “satisficing” answer, in which the project is compressed to a desired completion time with a prespecified tolerable relative error. We treat the problem of constructing the optimal first degree interpolating linear spline that guarantees such maximal error and consider various possible refinements. 相似文献
97.
The sugars in the dried Iraqi figs (Wazeri Variety) were examined by paper chromatographic analysis. Glucose comprised (34.30%), and fructose (31.20%) together with (7.82 %) of the fruit. Polysaccharides were found to be arabogalactans. Iron, calcium and phosphorus were found to be 14, 145 and 150 mg per 100 g dry weight respectively. Hydrolysis showed the presence of all the essential amino acids with adequate lysin and sulphur amino acids but relatively little tryptophan. 相似文献
98.
R. S. Farag H. El-Oksh M. H. Salem A. A. M. El-Sharabasy 《European Journal of Lipid Science and Technology》1982,84(8):313-317
The protective effect of egg yolk citrate, egg yolk skimmed milk, and egg yolk lactose extenders on the sperm cell against freezing injury was studied using Ossimi and Rahmani rams. Advanced motility, dead and coiled tail percentages of fresh spermatozoa did not differ significantly between the two breeds. Freezing caused a highly significant increase in dead and coiled tail percentages of spermatozoa diluted with various extenders. Unsaponifiable matter of fresh spermatozoa of both breeds contained various hydrocarbons and sterols with C 26, C 24 and cholesterol being the basic compounds. The unsaponifiables distribution could be used to characterize the spermatozoal origin. Changes in total sterols/total hydrocarbons ratios of the unsaponifiables were occurred after freezing of both breeds using the three extenders. Cholesterol content of fresh spermatozoa and the changes in physical properties of spermatozoa of both breeds indicated that the freezability of Ossimi semen was better than that of Rahmani. Also, the changes occurred in physical properties and total sterols/total hydrocarbons ratios showed that egg yolk lactose extender was better than egg yolk skimmed milk and egg yolk citrate extenders for sperm protection against freezing injury. 相似文献
99.
E. M. S. Salem A. M. El-Naggar M. A. Zewail 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1974,24(12):745-749
Sixteen copper complexes of di-, tri- and hexapeptides containing N2, N4-diaminobutyric acid are studied spectrophotometrically. The λmax, and colour of the complex is independent of the sequence of the amino acid in any of these peptides. The N4-amino group of the A2bu-residues do not participate in complex formation. However, the hydrazide group of di- and tripeptide hydrazides participates in complex formation. 相似文献
100.