Search

Tubular solid oxide fuel cells (SOFCs) composed of Ni- yttria- stabilized zirconia (YSZ) supported scandia-stabilized zirconia (SSZ) electrolyte film, doped ceria interlayer and strontium-doped cobaltile electrodes were successfully developed for reduced-temperature operation. The SOFCs were fabricated by adopting a slurry coating technique, which allows to prepare a ceramic layer with a thickness varied between 1~ca. 150um, and a co-fire process. The fabrication process was investigated in detail for realizing low cost SOFCs with high degree of straight, round, high reproductive quality, and high electrochemical performance. Flawless dense electrolyte thin film less than 10um was achieved on porous tubular Ni-YSZ substrate with the thickness that thicker than 500um. Primary results of electrochemical performance test show that the a fabricated cells with (Sm0.6Sr0.4)CoO3 electrode could produce ca. 0.4 Wcm-2 of power density at H2 utilization of 60% at 800oC.

Summary: Biochemical studies on human prolidase (EC 3.4.13.9) and prolidase deficiency are described. The urine sample from a 32-year-old female with prolidase deficiency was examined. Diagnosis was based on clinical features and defects of prolidase in her erythrocytes. She excreted massive amounts of iminopeptides, where three major peptides were identified; aspartyl-proline, glutamyl-proline and glycyl-proline. The prolidase was purified approximately 10,000-fold from the normal human erythrocytes through an eight step procedure. The purified enzyme consisted of two identical subunits of which the molecular weight was calculated to be 55,000. The relative cleavage rates of the enzyme for glycyl-L-proline, L-alanyl-L-proline, L-leucyl-L-proline, L-prolyl-L-proline, and glycyl-hydroxy-L-proline were 100%, 53%, 27%, 31% and 2%, respectively. The relative substrate specificity of the enzyme offers a reasonable explanation for the presence of a higher level of urinary imidodipeptides in a patient with prolidase deficiency. An attempt at erythrocyte transfusion was performed, aimed at enzyme replacement therapy. After the transfusion (erythrocytes from 800 ml of whole blood), the prolidase activity of the peripheral erythrocyte was elevated to approximately 35% of the normal values and gradually decresed (half-life, 41 days). During this period urinary peptide-bound proline was monitored, but no significant change was observed.Speculation: The prolidase activity of transfused erythrocytes is relatively stable; however, intracellular enzyme activity has no effect on net proline loss and skin lesions. Enzyme replacement may be a possible attempt at therapy of the disease, but other forms of replacement should be tried.

• Three patients had prolidase deficiencies. The family pedigree of these three patients suggests that this rare disorder is inherited through an autosomal recessive gene. This genodermatosis is characterized by a number of signs and symptoms referable to the skin, CNS, teeth, ears, nose, throat, eyes, bones, and joints. Among the skin changes, recalcitrant leg ulcers are the most characteristic. At this time, there is no established method of treatment of this rare disorder, but the use of dapsone was helpful in the treatment of one of our patients.(Arch Dermatol 1981;117:689-694)

Tubular solid oxide fuel cells (SOFCs) composed of Ni- yttria- stabilized zirconia (YSZ) supported scandia-stabilized zirconia (SSZ) electrolyte film, doped ceria interlayer and strontium-doped cobaltile electrodes were successfully developed for reduced-temperature operation. The SOFCs were fabricated by adopting a slurry coating technique, which allows to prepare a ceramic layer with a thickness varied between 1~ca. 150μm, and a co-fire process. The fabrication process was investigated in detail for realizing low cost SOFCs with high degree of straight, round, high reproductive quality, and high electrochemical performance. Flawless dense electrolyte thin film less than 10μm was achieved on porous tubular Ni-YSZ substrate with the thickness that thicker than 500μm. Primary results of electrochemical performance test show that the a fabricated cells with (Sm0.6Sr0.4)CoO3 electrode could produce ca. 0.4 Wcm-2 of power density at H2 utilization of 60% at 800oC.