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  • Nitrogen control  (2)
  • 71.00  (1)
  • Amyloidosis  (1)
  • Angiography  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 59 (1994), S. 245-251 
    ISSN: 1432-0630
    Keywords: 71.00 ; 61.70
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract An electron trap having an energy level of 0.14 eV from the conduction band edge was found in the bulk of copper-diffused VPE-grown n-GaAs0.6P0.4 by conventional DLTS measurements and by pulse-duration dependent capacitance amplitude measurements. The capture cross section at room temperature is about 1.0×10−21 cm2 and has a weak temperature dependence. These properties are attributed to a non-repulsive center having a capturing mechanism which involves multiphonon emission processes with hardly any lattice relaxation. Evolution of the spatial distributions of the traps with time under junction electric field were studied. The results suggest that the trap is positively charged and has a high diffusivity under electric field. The center can thus be identified as positively charged interstitial copper ion rather than some form of copper complexes.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0509
    Keywords: Amyloidosis ; Hamartoma ; Kidney ; Computed tomography ; Ultrasound
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We report two cases of renal amyloidosis associated with mesenteric and mediastinal Castleman disease of plasma cell type. Computed tomographic (CT) scan revealed a mesenteric mass with multiple nodal enlargement in one patient and a right paratracheal mass with irregular central calcifications in the second patient. Renal ultrasonography (US) showed increased echogenicity of the renal parenchyma with prominent medullas. Doppler waveform obtained in the kidney associated with mesenteric disease showed complete absence of diastolic flow signal, although it was normal in the patient with mediastinal disease. Recognition of Castleman disease as the cause of renal amyloidosis and the understanding of CT and US findings of this entity are important for the management, as well as its diagnosis.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-0509
    Keywords: Liver, neoplasms ; Sonography ; Angiography ; Computed tomography ; Oily contrast media
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract To evaluate the characteristics of combined hepatocellular and cholangiocarcinoma of the liver by imaging techniques, six patients (five male and one female), aged 46–60 years, with proved combined tumors were selected for this study from the review of 500 resected specimens of liver tumors. Images obtained from sonography, computed tomography (CT), angiography, and CT after intraarterial injection of iodized oil (iodized-oil CT) were retrospectively reviewed and correlated with the appearance of pathologic specimens. Sonographic findings were round or ovoid hypoechoic masses with central hyperechoic area (target appearance) in all patients. On CT scans, tumors were relatively well-defined low- and/or iso-attenuation masses in all patients. Angiography showed hypovascular masses in five patients. In one patient, the tumor appeared as a hypovascular mass with a central hypervascular area. On iodized-oil CT scans, all patients showed partial retention of iodized oil in tumors. Echogenicity in tumors at sonography or attenuation in tumors at CT could not be correlated with histologic difference in tumors at pathologic specimens. However, the hypervascular area at angiography and the compact retention areas of iodized oil at iodized-oil CT corresponded to portions of hepatocellular carcinoma within the combined tumor. On the basis of our results, imaging features, including target appearance at sonography, hypovascular mass with central hypervascular portions at angiography, and partial retention of iodized oil in tumors at iodized-oil CT, might be helpful in making accurate diagnosis of these rare tumors.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-072X
    Keywords: Nitrogen control ; Glutamate dehydrogenase ; Urease ; Histidase ; Glutamine auxotrophs ; Glutamine synthetase ; Pseudomonas aeruginosa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In Pseudomonas aeruginosa the formation of urease, histidase and some other enzymes involved in nitrogen assimilation is repressed by ammonia in the growth medium. The key metabolite in this process appears to be glutamine or a product derived from it, since ammonia and glutamate did not repress urease and histidase synthesis in a mutant lacking glutamine synthetase activity when growth was limited for glutamine. The synthesis of these enzymes was repressed in cells growing in the presence of excess glutamine. High levels of glutamine were also required for the derepression of NADP-dependent glutamate dehydrogenase formation in the glutamine synthetase-negative mutant.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-072X
    Keywords: Amidase ; Nitrogen control ; Glutamine synthetase ; Pseudomonas aeruginosa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The formation of amidase was studied in mutants from Pseudomonas aeruginosa PAO lacking glutamine synthetase activity. It appeared that catabolite repression of amidase synthesis by succinate was partially relieved when cellular growth was limited by glutamine. Under these conditions, a correlation between amidase and urease formation was observed. The results suggest that amidase formation in strain PAO is subject to nitrogen control and that glutamine or some compound derived from it mediates the nitrogen repression of amidase.
    Type of Medium: Electronic Resource
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