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Papers by Ahmed Adem
Urological Research, 2003
Collagen and blood vessels of the urethral submucosa of ovariectomized rats were studied followin... more Collagen and blood vessels of the urethral submucosa of ovariectomized rats were studied following 28 daily subcutaneous injections of 17-ß estradiol (n=6, group 1), medroxy-progesterone acetate (n=6, group 2), both drugs (n=6, group 3) or vehicle (n=6, control) and after sham surgery without castration or injection (n=6). Investigations included the immunohistochemistry of estrogen and progesterone receptors and collagen fibres, Western blot analysis of collagen types I and III and counting periurethral vessels by light microscopy. Our results showed positive immunostaining with estrogen, progesterone and collagen types I and III in all samples. Collagen type I and III levels were lower in the controls than in the sham group. The other groups showed increases (2>3>1) over the controls with a relatively higher increase in type III. The type I/III collagen ratio progressively decreased (control>1>2>3) below sham levels. The mean vessel count was significantly lower in control than in sham animals (P<0.00001). However, only estrogen treatment significantly increased the vessel number compared to controls (P=0.04). Our results indicate that estrogen and progesterone, alone or in combination, have an effect on collagen types I and III, and that estrogen has an effect on blood vessels of the urethral submucosa in female rats.
Annals of Nuclear Energy, 2009
Prospective fuels for a new reactor type, the so called fixed bed nuclear reactor (FBNR) are inve... more Prospective fuels for a new reactor type, the so called fixed bed nuclear reactor (FBNR) are investigated with respect to reactor criticality. These are ① low enriched uranium (LEU); ② weapon grade plutonium + ThO2; ③ reactor grade plutonium + ThO2; and ④ minor actinides in the spent fuel of light water reactors (LWRs) + ThO2. Reactor grade plutonium and minor actinides are considered as highly radio-active and radio-toxic nuclear waste products so that one can expect that they will have negative fuel costs.The criticality calculations are conducted with SCALE5.1 using S8–P3 approximation in 238 neutron energy groups with 90 groups in thermal energy region. The study has shown that the reactor criticality has lower values with uranium fuel and increases passing to minor actinides, reactor grade plutonium and weapon grade plutonium.Using LEU, an enrichment grade of 9% has resulted with keff = 1.2744. Mixed fuel with weapon grade plutonium made of 20% PuO2 + 80% ThO2 yields keff = 1.2864. Whereas a mixed fuel with reactor grade plutonium made of 35% PuO2 + 65% ThO2 brings it to keff = 1.267. Even the very hazardous nuclear waste of LWRs, namely minor actinides turn out to be high quality nuclear fuel due to the excellent neutron economy of FBNR. A relatively high reactor criticality of keff = 1.2673 is achieved by 50% MAO2 + 50% ThO2.The hazardous actinide nuclear waste products can be transmuted and utilized as fuel in situ. A further output of the study is the possibility of using thorium as breeding material in combination with these new alternative fuels.
Urological Research, 2003
Collagen and blood vessels of the urethral submucosa of ovariectomized rats were studied followin... more Collagen and blood vessels of the urethral submucosa of ovariectomized rats were studied following 28 daily subcutaneous injections of 17-ß estradiol (n=6, group 1), medroxy-progesterone acetate (n=6, group 2), both drugs (n=6, group 3) or vehicle (n=6, control) and after sham surgery without castration or injection (n=6). Investigations included the immunohistochemistry of estrogen and progesterone receptors and collagen fibres, Western blot analysis of collagen types I and III and counting periurethral vessels by light microscopy. Our results showed positive immunostaining with estrogen, progesterone and collagen types I and III in all samples. Collagen type I and III levels were lower in the controls than in the sham group. The other groups showed increases (2>3>1) over the controls with a relatively higher increase in type III. The type I/III collagen ratio progressively decreased (control>1>2>3) below sham levels. The mean vessel count was significantly lower in control than in sham animals (P<0.00001). However, only estrogen treatment significantly increased the vessel number compared to controls (P=0.04). Our results indicate that estrogen and progesterone, alone or in combination, have an effect on collagen types I and III, and that estrogen has an effect on blood vessels of the urethral submucosa in female rats.
Annals of Nuclear Energy, 2009
Prospective fuels for a new reactor type, the so called fixed bed nuclear reactor (FBNR) are inve... more Prospective fuels for a new reactor type, the so called fixed bed nuclear reactor (FBNR) are investigated with respect to reactor criticality. These are ① low enriched uranium (LEU); ② weapon grade plutonium + ThO2; ③ reactor grade plutonium + ThO2; and ④ minor actinides in the spent fuel of light water reactors (LWRs) + ThO2. Reactor grade plutonium and minor actinides are considered as highly radio-active and radio-toxic nuclear waste products so that one can expect that they will have negative fuel costs.The criticality calculations are conducted with SCALE5.1 using S8–P3 approximation in 238 neutron energy groups with 90 groups in thermal energy region. The study has shown that the reactor criticality has lower values with uranium fuel and increases passing to minor actinides, reactor grade plutonium and weapon grade plutonium.Using LEU, an enrichment grade of 9% has resulted with keff = 1.2744. Mixed fuel with weapon grade plutonium made of 20% PuO2 + 80% ThO2 yields keff = 1.2864. Whereas a mixed fuel with reactor grade plutonium made of 35% PuO2 + 65% ThO2 brings it to keff = 1.267. Even the very hazardous nuclear waste of LWRs, namely minor actinides turn out to be high quality nuclear fuel due to the excellent neutron economy of FBNR. A relatively high reactor criticality of keff = 1.2673 is achieved by 50% MAO2 + 50% ThO2.The hazardous actinide nuclear waste products can be transmuted and utilized as fuel in situ. A further output of the study is the possibility of using thorium as breeding material in combination with these new alternative fuels.