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Superconducting properties of ceramic samples Pb2Sr2Y1−xCaxCu3O8+δ have been investigated in the wide composition-range of 0≦x≦0.8 and 0≦0

Single crystals of Sr14-x Ca x Cu24O41 with dimensions on the order of 1×0.05×1.5 mm3 (x=0) and 0.3×0.05×2 mm3 (x=6.8) have been grown using NaCl as a flux. Anisotropic properties of the electrical resistivity and the thermoelectric power of these single crystals have also been investigated.

Single crystals of Pb2Sr2Ho0.5Ca0.5Cu3O8 have been grown in Pt, Al2O3 and Au crucibles by means of the flux method. The effect of contamination from the crucible on T c has been investigated by studing the effects of Cu-site substitution on T c and magnetic properties for sintered polycrystals of Pb2Sr2R0.5Ca0.5( Cu1- y M y )3O8 with R= Ho or Y and M= Pt or Al. Consequently, it has been found that use of a Pt crucible leads to growth of single crystals of the best quality with high T c values and that Al2O3 and Au crucibles contaminate the single crystals to decrease T c. Anisotropy in the electrical resistivity of the single-crystal Pb2Sr2Ho0.5Ca0.5Cu3O8 has been found to be comparable to that of YBa2Cu3O7 in spite of its thick blocking layer, suggesting that the wave functions of conduction electrons moderately overlap along the c-axis in Pb2Sr2Ho0.5Ca0.5Cu3O8.

Effects of the La substitution for Pr on the superconductivity and the electrical resistivity have been investigated in Pr2-y La y-x Ce x CuO4-δ of the T′-phase. For heavily La-substituted samples of 1.0≦y≦1.2, superconductivity of the bulk appears in the range of smaller x values, 0.10≦x\lesssim0.15. This is discussed in relation to the electrical resistivity and the carrier concentration in the CuO2 sheet.

Plasma membrane preparations were isolated from mononuclear leukocytes obtained from 18 children with IDDM (insulin-dependent diabetes mellitus), 9 healthy children, and 8 normal adults.Their β-adrenergic receptor (β-receptor) was studied using 125I-iodohydroxybenzylpindolol (125I-IHYP) as a radioligand. The β-receptor densiy in the mononuclear leukocytes of the IDDM patients was found to be decreased (Bmax = 27.6 ± 2.0 fmol 125I-IHYP/mg protein : mean ± SE) compared with those of normal children (40.4 ± 3.5) and normal adults (36.9 ± 2.1), while no significant difference was seen in the density between normal children and adults. There were no significant differences in the binding affinities among those groups. When the IDDM patients were divided into groups on the basis of their blood glycosylated hemoglobin (HbAl) levels, group B patients (HbAl≥10%, n=9) had smaller receptor densities in the leukocytes than group A patients (HbAl

The observation that N alpha,B1-biotinylinsulin binds firmly to resins in which succinoylavidin is covalently attached to AH Sepharose 4B and can be retrieved by exposure of the resins to 20 mM biotin provided the basis for the present investigations. Solubilized, partially purified insulin receptor from human placenta binds to affinity resins in which N alpha,B1-biotinylinsulin is noncovalently attached to AH Sepharose 4B-immobilized-succinolylavidin. Exposure of the receptor loaded resin to 20 mM biotin results in liberation of a high molecular weight material containing bound 125I-biotinylinsulin, which precipitates with polyethyleneglycol and cross reacts with human insulin receptor antibodies. The technique is biospecific and appears to be applicable to the purification of insulin receptors on a preparative scale. Crude solubilized insulin receptor from human placenta is contaminated with "insulinase" which is inhibited by N-ethylmaleimide. HPLC provides a tool to assess "insulinase" activity that is more sensitive than the TCA precipitation method.

The levels of corticotropin-releasing factor (CRF) in the cord blood from 34 infants were determined by radioimmunoassay. All infants were born by vaginal delivery after an uneventful pregnancy. Levels of cortisol, dehydroepiandrosterone sulfate and ACTH were high in the cord blood. CRF levels (mean ± SD) were 100.5 ± 31.7 and 44.5 ± 7.8 pg/ml, respectively, in cord blood and in controls (healthy prepubertal children, n = 10). Although the origin of CRF in peripheral circulation has not been clarified, we speculate that the high adrenocortical steroid synthesis of the fetus might be a consequence of high CRF levels in fetal circulation.

Epidermal growth factor (EGF) in human milk, cow's milk and 10 different milk formulas was measured by radioreceptor assay (RRA) using human placental membrane as an EGF receptor. The raw and pasteurized cow's milk contained 324.2 ng/ml and 155.0 ng/ml of RRA-EGF, respectively. These values were almost the same as that found in human milk, when the concentration was expressed as the proportion of protein contents in the samples. On the other hand, no trace of RRA-EGF was detected in 9 different milk formulas, and only one contained a very small amount of it.

We report the analytical results of Cu valence and the amount of oxygen deficiency in high T c superconductors, Sr x La2-x CuO4-y . These results show that for the sample with x=0, the valence state of all Cu ion is proved to be Cu2+. Amount of Cu3+ and oxygen deficiency linearly increase with increasing Sr. According to this, there is no clear correlation between the transition temperature and the oxygen deficiency.

The dependence of T c of the superconducting ceramics Sr x La2-x CuO4 was measured on the sintering conditions, temperature and time, on the cooling rate after annealing and on the depth from the initial surface of the sample. The sintering temperature 1050°C was better than 1000°C and the sintering for five hours was the best one. There was no difference between the superconductivity of the initial surface and of the inside of the sample.

Good quality samples of the high-T c superconductor Pb2Sr2Y0.5Ca0.5Cu3O8+δ have been prepared by solid-state reaction under low oxygen pressure and adequate post-annealing in flowing nitrogen gas. The best sample shows metallic temperature dependence of the resistivity above T c, an onset of the superconducting transition at 83 K and zero resistance at 75 K. The adequate post-annealing, which is considered to decrease crystalline disorder, is effective in attaining good superconducting quality.

High Tc superconductor M-La-Cu-O systems (M=Ba, Sr), with the composition (M x La1-x )2CuO4-y , have been prepared by a ceramic technique and the compositional change of Tc-value have been examined. Then in each of systems the partial substitution of Ag or Hg for Cu brought the increase of Tc-value.

A sort of the layered perovskite (Sr1-z Ca z )0.15La1.85CuO4-y was prepared by a ceramic technique. Electrical resistance was measured for the various substitution ratio z. It exhibited the highest T c value at z=0.03. The dependence of T c upon the composition of sintering atmosphere (N2-O2 mixed gas) was also studied. At the oxygen partial pressure of 530 Torr, T c exhibited the highest value.

High T c superconductors, YBa2(Ag x Cu1-x )3O9-y with composition of 0≦x≦0.6 were prepared by a ceramic technique, and the compositional change of T c was examined. Samples with nominal compositions of x2(Ag0.1Cu0.9)3O9-y and YBa2(Ag0.2Cu0.8)3O9-y , show sharp superconducting transitions with widths as narrow as about 1 K or less. The superconductivity is discussed in relation to the results of X-ray diffraction study.

We report results of substitution effect of Ag for Cu as a function of x (0.0≦x≦1.0) in high T c superconductors, (Ba0.1La1.9)Ag x Cu1-x O4-y compounds. Transition temperatures increased with a small amount of Ag and are nearly constant in a wide composition range of x (0.05

Superconducting properties in Sr-La-Cu-O system prepared by the coprecipitation method were studied. The highest T c of the samples was about 42 K, rather higher than that of the samples by a solid-state reaction. It was found that the composition (especially that of Sr) of the sintered samples was different from the nominal formation.

The concentration dependence of the transition temperature Tc has been studied in high-Tc Y1-xBaxCuO3-y and Y(Ba1-xSrx)2Cu3O7-y systems. In Y1-xBaxCuO3-y, Tc exhibits a maximum at x=0.67 compound with a stoichiometry YBa2Cu3O7-y. In Y(Ba1-xSrx)2Cu3O7-y, Tc decrease monotonically with an increase of Sr content.