Vol. 1 Issue 2
Mohamed I. Naguib, AJeya A. Hamed and Nahed Z. Haikal
In absence of external carbon source, the loss in weight from 6-day old mycelial felts was greater with Fusarium oxysporum than with Cunninghamella echinulata when supplied with nitrate, though carbon dioxide output was almost similar.
Although the three tin compounds seemed to exert no effect on growth of Cunninghamella when supplied with nitrate alone, stannous ions stimulated growth on either urea or peptone media . On the other hand, the three compounds were toxic to Fusarium when supplied with urea. With an adequate supply of carbon, the inorganic tins enhanced, but Plictran inhibited, growth of Cunninghamella. Nitrate favored
greater absorption of sugar than either urea or peptone. Stannic and Plictran were suppressive to glucose uptake by Cunninghamella when supplied with either nitrogen sources, whereas stannous exerted almost no effect with nitrate or urea but was suppressive with peptone. The tin compounds also hindered glucose uptake by Fusarium, a phenomenon that was alleviated or even reversed with urea feeding.
Inorganic tin stimulated respiration of Cunninghamella in the presence of nitrate, while respiration was inhibited in the presence of urea. Plictran inhibited respiration in media containing either nitrate or urea. On the other hand, the three tin containing compounds enhanced respiration of Fusarium regardless of the nitrogen source. Further, the presence of glucose in media containing tin attenuated respiration of
Cunninghamella, regardless of the nitrogen source.
The results show that glucose slightly suppressed nitrogen absorption from urea or peptone , but remarkably increased nitrogen uptake from nitrate media. In most cases, the various tin compounds inhibited nitrogen absorption by Cunninghamella when glucose was supplied to the media. In the absence of glucose, the tin compounds stimulated urea and peptone absorption.
F.A. Abou-Elfotouh, M.A. AI-mass'ari, A. Felimban and M.K. Katib
The practical utilization of the photovoltaic effect in hybrid junctions between p-Si substrates and n- (Znx -Cd1-x) S was observed. The performance of junctions prepared on hot substrates (Tsb > 200⁰C) and annealed in sulfur and air atmosphere for 20 minutes at temperature Ta> 350⁰C is given by 0.57 V for Voc , 15 mA/cm2 for Isc and 7 percent for conversion efficiency. A proper cleaning method to get rid of oxygen contaminating the Si surface is necessary.
Hussain M. Rizk
The inner and outer Magnetohydrodynamic equilibrium equations of the circular toroidal plasma Tokamak cross section solved to the first order of the inverse aspect ratio. The toroidal current density is of arbitrary profile. The shape of the conducting shell surrounding the plasma is determined.
M.A. Abdulmomen, H.H. Aly and H.M.M. Mansour
We study various short range potentials and calculate their eigenvalues for both s- and p-waves using a wide range of coupling constants. We obtain these eigenvalues, first by perturbation methods, then compare these values with the ones obtained numerically and when it is possible by exact methods. Good agreements are obtained for s-waves eigenvalues and the implications for higher angular momenta eigenvalues are discussed.
S. AI-Barrak and G. Hussain
A study into the climatic conditions of Central and Eastern regions in the Kingdom of Saudi Arabia over a period of 236 years indicated both drought and without drought periods. The duration of drought varied from 1 to 7 years whereas that of without drought varied from 8 to 44 years. Study of the agro-climatic conditions usually gives a good approximation of the existing crop growth conditions. In general, it also shows promising areas of research in plant breeding for drought resistance, water management for better moisture conservation and future project planning.
A.M.A. Ismail
A comparison of the germination capacity of seeds of three cultivars of Medicago sativa L. of diverse geographic origin in water of different sources, solutions of sodium chloride and mannitol was investigated. The degree of germination retardation varies in the same species with the variation of the medium. The results indicate that salinity affects the rate of germination adversely and the presence of sodium chloride in the germination culture inhibited germination significantly more or less than that due to moisture stress [mannitol]. Kinetin applied simultaneously with NaCl or mannitol to seeds altered the stress response and the stressed seeds responded to kinetin more than did unstressed seeds. It is concluded that kinetin plays and important role in plant response to stress and that Hassawi and AS-49R appear to be very similar as salt tolerant cultivars and cv. Diabloverd is a little more tolerant at the highest salt levels.
A.R. Gourlay and J.LI. Morris
The extrapolated Backward Euler method described by the authors in a previous paper is generalized to apply to both variable coefficient and inhomogeneous partial differential equations of parabolic type. Methods of orders two, three and four are discussed.