The oxygen diffusion coefficient of YBa
2Cu
3O
y
(YBCO) single crystals was determined by secondary ion mass spectrometry in a wide temperature range from 628 to 1073 K. It was found that the slope ...of the Arrhenius plot of the diffusion coefficient changes at the transition temperature from the orthorhombic to the tetragonal phase (TP). The activation energies of oxygen in the TP and the orthorhombic phase (OP) are 89.1±1.4 and
114.6±1
kJ
mol
−1
in the
ab plane, and 284±2.8 and
126.9±0.5
kJ
mol
−1
in the
c axis direction, respectively. In the OP, the activation energies in the
ab plane and the
c axis direction are almost the same, but the diffusion coefficients in the
ab plane are larger than that in the
c axis direction by more than three orders of magnitude. At higher temperatures of the TP, the slope of the Arrhenius plot in the
c axis direction becomes larger and the diffusion coefficient of the
c axis becomes closer to that of the
ab plane towards the incongruent melting point of YBCO compounds.
We have prepared Bi-2201 thin films of Bi
2Ln
x
Ca
2−
x
Cu
1O
z
systems (Ln=La, Pr, Nd, Sm, Eu and Gd) by the laser ablation method. In the Bi
2La
x
Ca
2−
x
Cu
1O
z
system, the Bi-2201 films have ...been obtained in a wide composition range of
0.4
≦
x
≦
0.8
, and the films with
x<0.7 have been of the metastable phase, which has never been reported to be synthesized by the solid state reaction method. The film with
x=0.4 has shown the lowest resistivity in the Bi
2La
x
Ca
2−
x
Cu
1O
z
system, and in the Bi
2Ln
x
Ca
2−
x
Cu
1O
z
systems (Ln=La, Pr, Nd, Sm, Eu and Gd), when
x is fixed to 0.4, the film with Ln=Nd has shown the lowest resistivity. From the results of resistivity and magnetic measurements, however, none of these films have been found to be superconductive.
We report that mechanical stimulation of human neutrophils results in their accumulation in isolated rat lungs and in an increase in pulmonary vascular permeability. To determine whether reactive ...oxygen species were involved in this increase and, if so, whether it is mediate by xanthine oxidase metabolites, we assessed the effect of stimulated and unstimulated neutrophils, and of a superoxide scavenger, superoxide dismutase (SOD), and a xanthine oxidase inhibitor, allopurinol (ALLO) on pulmonary vascular permeability in isolated perfused lungs from Sprague-Dawley rats. Pulmonary vascular permeability in isolated rat lungs was assessed using a filtration coefficient determined by gravimetry. To quantify neutrophil accumulation in the lung, we measured myeloperoxydase (MPO). Neutrophils were stimulated by gentle agitation in a glass container for 10 s and Mac-1 was subsequently upregulated on the surface of the neutrophils. In lungs that received stimulated neutrophils, the pulmonary vascular filtration coefficient was about 5 times higher than in lungs that received unstimulated neutrophils. An increase in filtration coefficient was almost completely blocked by pretreatment with SOD or ALLO. However, the accumulation of stimulated neutrophils was not, or only partly, blocked by SOD or ALLO, respectively. We conclude that the increase in pulmonary vascular permeability caused by mechanically stimulated neutrophils was partly mediated by reactive oxygen species generated via the xanthine oxidase system.
To determine the systolic characteristics of the hypertrophied myocardium in patients with hypertrophic cardiomyopathy (HCM), we evaluated the left ventricular left ventricle (LV) myocardial velocity ...profile (MVP) and gradient obtained from tissue Doppler imaging (TDI). Transmural wall‐motion velocities in the ventricular septum and LV posterior wall were recorded in 12 patients with asymmetric septal hypertrophy and 12 healthy volunteers, and their profiles and gradients were determined. The maximum systolic myocardial velocity gradient in the ventricular septum was significantly lower in the HCM group than in the control group (0.88 ± 0.35 versus 2.24 ± 0.41; P < 0.001), whereas the gradient in the LV posterior wall was only slightly lower in the HCM group than in the control group (2.69 ± 0.82 versus 3.45 ± 0.96). In the control group, the MVPs in the ventricular septum and LV posterior wall were closely linear, suggesting that the transmural velocity is uniform during systole. MVPs in the ventricular septum and LV posterior wall in the HCM group also were closely linear, whereas the distribution of velocities in the ventricular septum was fairly dispersed compared with the control group. The myocardial velocity gradient on the right ventricular side of the ventricular septum decreased or disappeared in the patients with HCM, suggesting a nonuniform distribution of velocities. In conclusion, the MVP and gradient obtained from TDI may represent new indices for evaluating regional LV contractile abnormality in patients with HCM.
Apatite ceramics composed of synthetic hydroxyapatite, Ca10(PO4)6(OH)2 were implanted in mandibles of adults dogs. The histological observations indicated that the apatite ceramic was closely ...contacted with newly formed bone tissue without any rejection phenomenon up to 2 weeks. An electron micrograph of non-decalcified ultra-thin section at 8 weeks showed that the apatite ceramic was directly bonded to newly formed bone and the mineralized bone tissue was grown into the micro pores of the ceramics independent on the pore size. It seemed that the outer surface of the apatite was exchanged by bone tissue. From these results it was considered that the apatite ceramic was a successful implant material in dental and surgical fields.
The localization of T and B lymphocytes in frozen sections of human tonsils was determined using E and EAC binding techniques. It was revealed that there were thymus-dependent areas with E binding ...lymphocytes in peri- and interfollicular zones. EAC binding lymphocytes were found mainly in the follicles. This suggests that B cells are produced in germinal centres. The present experiment confirmed that human tonsils contain two different kinds of lymphocytes demonstrating selective localizations in the tissues as similar to the lymph nodes.
Range distributions of electrons in elemental solids of atomic number between 4 and 92 (Be, C, Al, Cu, Ag, Au and U) have been computed with the ITS Monte Carlo system version 3.0. Incident energies ...of electrons considered are from 0.1 to 100 MeV. Values of the projected range
r
pr the relative deviation of
r
pr from the average depth of charge deposition and the detour factor have been obtained; the last parameter is defined as the ratio of the continuous slowing-down approximation range to
r
pr. Present values of the detour factor are compared with other authors' results as well as the semiempirical equation proposed by Tabata et al. J Appl. Phys. 42 (1971) 3361. Prospective use of the equation in the field of therapeutic electron beams is suggested.
Angiographic findings of the cerebral atrophy in children are discussed. Cerebral angiographies were performed on 20 patients, ranging from 6 months to 16 years of age. Their clinical diagnoses were ...H-H-E syndrome (4 cases), sequelae of meningoencephalitis (2), sequelae of head trauma (3), infantile spasms (2) and others (9). Final radiological diagnoses of these cases were hemiatrophy (14 cases), generalized atrophy (2) and focal atrophy (4). Circulation time, caliber of arteries, degree of opacification in cortical and deep veins and early filling of deep veins were investigated on angiogram. Slow circulation of cerebral blood flow was shown in 10 cases and normal circulation in 10 cases. Arterial narrowing was observed more frequently in slow circulation group. In cases with hemiatrophy, small caliber of the middle cerebral arteries and slow circulation on the atrophic hemisphere were demonstrated, but no abnormality on the normal side. Deep veins were prominently opacified in cases which showed poor cortical veins, the other way cortical veins were prominent in cases which showed poor visualization of deep veins. Cortical veins and deep veins may compensate each other in cerebral venous drainage. In most cases of slow circulation, dominant opacification of deep veins were visualized and these veins already appeared in arterial phase, but cortical veins had a tendency of poor opacification. These venous drainage patterns are similar to those of Sturge-Weber syndrome. Causes of these vascular changes are unknown. But they may play an important role in cerebral atrophic disorders.(ABSTRACT TRUNCATED AT 250 WORDS)
