Estimation of formation mechanism of spherical fine ZrO2-SiO2 particles by ultrasonic spray pyrolysis

Spherical fine ZrO₂-SiO₂ (11) particles were synthesized from a hydrolysed mix-solution of Si(OC₂H₅)₄ and ZrOCI₂ · 8H₂O by ultrasonic spray pyrolysis, and the formation mechanism of the particles discussed. All of the resultant particles identified as t-ZrO₂ and amorphous SiO₂ with an atomic order dispersion were spherical, and mainly of diameter 0.8 to 1.0m. It was estimated that the three-dimensional ladder siloxane chains containing an equimolar Zr⁴⁺ homogeneously dispersed were formed by hydrolysis, and an atomized droplet itself converted into an isolated ZrO₂-SiO₂ (11) particle without aggregation.     

Molecular analysis of glucose phosphate isomerase deficiency associated with hereditary hemolytic anemia

We report here two new cases of glucose phosphate isomerase (GPI) deficiency associated with hemolytic anemia and present the results of molecular analysis of the five Japanese GPI variants. A Japanese girl (GPI Fukuoka) had an episode of prolonged neonatal jaundice and at 3 years of age was admitted due to acute hemolytic crisis occurring with upper respiratory tract infection. Red blood cell (RBC) GPI activity was decreased to 11.8% of normal and the reduced glutathione (GSH) level of RBCs was slightly decreased. A 54-year-old Japanese man (GPI Iwate) was hospitalized due to chronic active hepatitis, and compensated hemolysis was noted. RBC GPI activity of the proband was decreased to 18.8%, and the GSH content was about half of the normal mean value. Sequencing of the reticulocyte GPIcDNA showed homozygous missense mutations 1028CAG-->CGG (343Gln-->Arg), 14ACC-->A7C (5Thr-->lle), 671ACG-->A7G (224Thr-->Met), and 1615GAC-->AAC (539Asp-->Asn) in GPI Narita, GPI Matsumoto, GPI Iwate, and GPI Fukuoka, respectively. We also identified GPI Kinki as a compound heterozygote of 1124ACA-->AGA(375Thr-->Arg)/ 1615GAC-->AAC(539Asp-->Asn). Our findings, together with the previous results of other investigators, showed that the GPI gene mutations so far identified were heterogeneous, although most GPI variants had common biochemical characteristics such as heat instability and normal kinetics. Several amino acid substitutions were identified in the proximity of the catalytically important amino acid residues such as Ser/Asp 159/160, Asp341, and Lys518, which have been identified in the structural analysis of the pig GPI. The molecular characterization of human GPI variants, therefore, may provide new insights into the genotype-phenotype correlation of GPI deficiency as well as the structure-function relationship of this enzyme.     

Contribution of Na+/Ca2+ exchanger in maintaining [Ca2+]c at a stable state in rat pancreatic islets

The effects of lowering extracellular Na+ concentration [Na+]o, on cytosolic Ca2+ concentration, [Ca2+]c were examined by a microfluorimetric method using fura-2 in perifused preparations of isolated rat pancreatic islets. The total replacement of extracellular Na+ (Na+o) by equimolar N-methyl-D-(--)-glucamine caused a rapid rise in [Ca2+]c, and partial replacement of Na+o resulted in correlative rises in [Ca2+]c in accordance with the magnitude of reduced [Na+]o. The rise in [Ca2+]c induced by Na+o removal was strongly inhibited in the Ca2+o-deficient environment or by Ni2+. The [Ca2+]c rise, however, remained almost unchanged in the presence of nifedipine or SK&F 96365, and was enhanced by the addition of ouabain. The electrochemical gradients for Ca2+ (delta mu Ca2+) and Na+ (delta mu Na+) were calculated to be 39.08 and 12.8 kJ/mol, respectively, in this study, indicating a stoichiometry of 3Na+: 1 Ca2+. These results indicate that, in rat pancreatic islets, the rise in [Ca2+]c induced by lowering [Na+]o is mainly due to Ca2+ entry medicated by the Na+/Ca2+ exchanger operating with the stoichiometry of 3Na+:1 Ca2+, and that the Na+/Ca2+ exchanger plays an important role in maintaining stable-state [Ca2+]c.     

Immunoreactivity of neoplastic and non-neoplastic monocytoid B lymphocytes for DBA.44 and other antibodies

AIMS--To evaluate the immunoreactivities of neoplastic and non-neoplastic monocytoid B cells (MBC) and compare them with hairy cell leukemia (HCL) and mantle cell lymphoma (MCL). METHODS--An immunohistochemical study of paraffin wax embedded sections was done on surgically resected specimens of spleens with MBC clusters from patients with gastric cancer (14 cases), tonsils (five cases), and lymph node (two cases) showing lymphoid follicular hyperplasia (LFH), submandibular lymph nodes containing MBC in Sj?gren's syndrome (one case). Extranodal organs affected by MCL (three cases) and monocytoid B cell lymphoma (MBCL) (seven cases), and spleens from HCL (four cases) were also studied. These specimens were fixed in 10% formalin and routinely processed for paraffin wax embedding. Fresh spleen specimens from patients with liver cirrhosis (one case) and gastric cancer (seven cases) were snap frozen. RESULTS--Mantle zone lymphocytes were DBA.44, CD74 positive and showed a weaker reaction for CDw75 than marginal zone lymphocytes and MBC, which were almost DBA negative. In neoplastic diseases tumour cells in MCL were DBA.44, CD74, and CDw75 positive. MBCL showed a positive reaction for CD74 and CDw75, but positivity for DBA.44 was observed in only one of seven cases. The HCL specimens, all positive for DBA.44, showed a weaker reaction for CD74 and a stronger reaction for CDw75 than either MCL and MBCL specimens. CONCLUSION--These results show that mantle zone lymphocytes and MCL more closely matched HCL for reactivity to DBA.44 than MBC and MBCL. Reactivities for DBA.44 and CDw75 were greater in MBCL compared with its non-neoplastic counterpart, MBC.     

Effects of fullerene C60 on the friction and wear characteristics of ceramics in ethanol

For the combinations of a pin of Si₃N₄ and five kinds of disk, the friction and wear test was carried out in ethanol, and in ethanol containing C₆₀ particles (1 wt%). A topographical analysis was also performed on the micro-asperities of the wear surfaces to estimate the behavior of C₆₀ particles, and the degree of surface damage. As a results, the following facts were found. (1) The addition of C₆₀ particles in ethanol decreased the wear rates of such ceramic disks as Al₂O₃, SiC and TiC and of the mating Si₃N₄ pins. (2) The addition of C₆₀ particles decreased the mean coefficient of friction for SiC, Si₃N₄, and TiC disks. (3) The wear rates of pin and disk depended on the topographies of worn surfaces such as the mean depth of micro-grooves, the mean tip radius of micro-asperities and so on.     

8-[2-(2-Pentyl-Cyclopropylmethyl)-Cyclopropyl]-Octanoic Acid and Its Diastereomers Improve Age-Related Cognitive Deterioration

Racemic 8-[2-(2-pentyl-cyclopropylmethyl)-cyclopropyl]-octanoic acid (DCP-LA), a linoleic acid derivative with cyclopropane rings instead of cis-double bonds, contains possible four diastereomers such as α,α-, α,β-, β,α-, and β,β-DCP-LA. The present study examined the effect of racemic and diastereomeric DCP-LA on age-related learning and memory disorders using accelerated-senescence-prone mice 8 (SAMP8) and accelerated-senescence-resistant mice 1 (SAMR1). In the water maze test, the acquisition and retention latencies for SAMP8 mice were significantly longer than the latency for SAMR1 mice, indicating spatial learning and memory impairment for SAMP8 mice. All the racemic (1?mg/kg, per os) and diastereomeric DCP-LA (0.25?mg/kg, per os) significantly shortened the acquisition latency for SAMP8 mice, and racemic, α,α- and α,β-DCP-LA significantly shortened the retention latency, with the advantage greater than the acetylcholine (ACh) esterase inhibitor galanthamine. The results of the present study show that all the racemic and diastereomeric DCP-LA, has the potential to improve age-related learning and memory deterioration, the potential varying among them.     

Piezoelectric properties of microfabricated (K,Na)NbO3 thin films

A novel microfabrication method of lead-free piezoelectric sodium potassium niobate [(K,Na)NbO₃, KNN] thin films was proposed, and the piezoelectric characteristics of the KNN microactuators were evaluated. The KNN thin films were directly deposited on microfabricated Si microcantilevers. The transverse piezoelectric coefficient d₃₁ of the KNN films was calculated as −53.5 pm/V at 20 V_pp from the tip displacement of the microcantilevers. However, the tip displacement showed large electric-field dependence because of the extrinsic piezoelectric effect, and the intrinsic piezoelectric effect of the KNN microcantilevers was smaller than that of KNN on unprocessed thick substrates. In contrast, the extrinsic piezoelectric effect was almost independent of the microfabrication of the KNN films.     

Strategy for kinetic parameter estimation—Thermal degradation of polyurethane elastomers

The kinetics of the thermal degradation of polyurethane (PU) elastomers based on poly(ether polyol) soft segments and an aromatic type of diisocyanate were investigated by thermogravimetric analysis (TGA) under a nitrogen atmosphere employing four heating rates. The corresponding kinetic parameters of the two degradation stages were estimated by minimizing the output error functional and by the Kissinger method. In evaluating the kinetic parameters of the two‐step PU thermal decomposition, a differential thermogravimetry curve was applied as an objective functional in a regression procedure. Parameter estimation was obtained by minimizing the weighted quadratic output error functional with the modified Nelder–Mead simplex search algorithm. The confidence regions in the preexponential factor‐activation energy space were established for both the first and second stages of degradation. The effect of the molecular weight of the soft segment and the content of the hard segment on the activation energy of the degradation process was constructed by response surface methodology. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 764–772, 2007