Peroxidase activity of ferritin in aerosol OT reversed micelles in heptane

The aim of the present investigation was to determine spin lock (SL) relaxation parameters for the normal brain tissues and thus, to provide basis for optimizing the imaging contrast at 0.1 T. 68 healthy volunteers were included. On-resonance spin lock relaxation time (T1rho) and off-resonance spin lock relaxation parameters (T1rho(off), Me/Mo), MT parameters (T1sat, Ms/Mo), and T1, T2 were determined for the cortical gray matter, and for the frontal and parietal white matters. The T1rho for the frontal and parietal white matters ranged from 110 to 133 ms and from 122 to 155 ms with locking field strengths from 50 microT to 250 microT, respectively. Accordingly, the values for the gray matter ranged from 127 to 155 ms. With a locking field strength of 50 microT, T1rho(off) for the frontal and parietal white matters were from 114 to 217 ms and from 126 to 219 ms, and for the gray matter from 136 to 267 ms with the angle between the effective magnetic field (B(eff)) and the z-axis (theta) ranging from 60 degrees to 15 degrees, respectively. The T1rho of the white and gray matters increased significantly with increasing locking field amplitude (p < 0.001). The T1rho(off) decreased significantly with increasing theta (p < 0.001). T1rho and T1rho(off) with theta > or = 30 degrees were statistically significantly shorter in the frontal than in the parietal white matters (p < 0.05). The duration, amplitude and theta of the locking pulse provide additional parameters to optimize contrast in brain SL imaging.     

Analysis of the t(2;5) (p23;q35) translocation in CD30+ primary cutaneous lymphoproliferative disorders and Hodgkin''s disease

To observe the expression of p16, pRb, cdk4 and cyclinD1 in non-small cell lung cancers, 104 cases of resected lung cancers were collected, which included squamous cell carcinomas, adenocarcinomas and large cell carcinomas. Immunohistochemistry assay was carried out. The results showed that 67% of squamous cell carcinomas and 46% of adenocarcinomas expressed p16, 64% of squamous cell carcinomas and 85% of adenocarcinomas expressed pRb and 66% of cancers expressed p16 or pRb. About 70% of the tumors expressed cyclinD1. More than 90% of the tumors expressed cdk4 and there was an increased trend with decreasing differentiation of both squamous cell carcinomas and adenocarcinomas. Sixty-seven percent of the highly differentiated and 100% of the poorly differentiated squamous cell carcinomas expressed cdk4. The aberrant p16 and pRb gene product expression played a significant role in the development and histological subtype of lung cancers by conditioning the biological behavior of NSCLC. cdk4 was an important factor in histological differentiation.     

Fatigue life prediction for notched members

The first stage of a general solution for notch fatigue has been the prediction and verification of the stress levels required to cause failure in notched components.Simple design equations have been produced which predict the stress level required to initiate a crack and, in sharply notched components, the higher stress level which must be exceeded before the initiated crack will propagate to failure.A general design approach is to consider both the initiation and propagation phases of the fatigue process. However, as an aid to design, situations have been identified where the consideration of only one phase is adequate. These situations have been identified on charts relating life, notch acuity and stress range. Thus, in many cases, the general design approach can be greatly simplified.     

Correlation of histopathologic characteristics of primary tumor and uninvolved regional lymph nodes in Dukes' class C colonic carcinoma with prognosis

Ninety-two patients with Dukes' class C colonic carcinoma, divided equally into those who survived 5 years or more and those surviving less than 5 years after resection for cure, underwent evaluation of multiple histopathologic characteristics of the primary tumor and the uninvolved regional lymph nodes. These characteristics were analyzed by the chi-square test for correlation with survival. A statistically significant correlation (P less than 0.05) in the group who survived 5 years or more was observed for Broders' grades 1 and 2, tumor not involving serosa, and a pushing tumor margin. Of the 14 patients who had a pushing tumor margin and tumor not involving serosa, 12 (86%) survived 5 years or more. Seven patients had an infiltrating tumor margin and peritumor venous invasion, and of this group, only one (14%) survived 5 years or more. Histopathologic characteristics of host immune reaction at the tumor or in the uninvolved regional lymph nodes did not correlate with survival.     

Heat of adsorption and critical temperature studies of boundary lubricants on steel surfaces

The study of heat of desorption on sliding steel surfaces under boundary lubrication gave an optimum surface roughness value at which the total heat is minimum. This value is both quantitatively and qualitatively analysed and identified as heat of desorption of molecules of additives from the base oil on to the steel surface and the activation energy of the interface material due to dislocation movement.It is shown that the change in entropy (ΔS) of the boundary lubricant is a controlling factor for effective lubrication. Limiting value of coverage for a particular value of change in entropy is necessary to prevent scuffing of steel surfaces. The study also reveals that a minimum value of concentration of polar additives is necessary for effective boundary lubrication. These results help to elucidate the mechanism of scuffing of the steel surfaces.     

A technique for anodally blocking large nerve fibres through chronically implanted electrodes

If a spinal root of a baboon or rhesus monkey is trapped in an initially loose-fitting silicone rubber channel containing two or more platinum electrodes, electrical pulses sent through these electrodes can stimulate nerve fibres close to the cathode and block the resulting impulses close to the anode. We show (1) how anodal break excitation and excitation of fibres outside the silicone rubber channel can be avoided; (2) that an implant 26 months old behaves like a recent one; (3) that in a root containing somatic motor fibres and parasympathetic fibres, all somatic motor fibres can be blocked and most or all parasympathetic fibres excited but not blocked; (4) that provided that the electrodes pass no net direct current, prolonged stimulation with block can be harmless; (5) how block can be achieved in one direction only along a root; (6) that a peripheral nerve can be blocked by the same techniques.     

Effects of poor solvents on radical-radical termination of polymerization

It is shown that in poor solvents for the polymer the rate coefficient for radical-radical termination in the polymerization of styrene and methyl methacrylate is diminished compared with that in bulk monomer. It is suggested that this effect is due to the formation of tightly coiled macroradicals which hinder the radical-radical reaction process.     

Addition of sec-butyllithium to m-diisopropenylbenzene

The reaction of equivalent quantities of sec-butyllithium with m-diisopropenylbenzene in cyclohexane and benzene solution in the presence and absence of catalytic amounts of triethylamine, does not yield the diadduct quantitatively. Oligomer formation occurs to varying extents depending on the reaction conditions, and, contrary to claims in the literature, this may not be a good route to a difunctional initiator for anionic polymerization.