Procedural outcome and follow-up results of balloon angioplasty versus new device interventions for treatment of true bifurcation stenoses

Strategies for dilatation of bifurcation stenoses have continued to evolve over the past several years. However, there is limited experience on the efficacy of various nonballoon interventional devices and their results in comparison with balloon angioplasty. We, therefore, analysed our data in 72 patients of coronary artery disease with true bifurcation stenoses with balloon angioplasty or new device interventions (NDI). All patients underwent dilatation of both the primary vessel and side branch ostial stenosis. Balloon angioplasty using double guidewire with sequential or simultaneous (kissing balloon) balloon inflation in the two vessels was performed in 42 patients. Thirty patients underwent NDI, using directional coronary atherectomy (DCA) in 12, rotablation in 6 and elective coronary stents in 12 patients. There were no significant differences in the baseline clinical and angiographic variables between patients in the two groups. While the preprocedural luminal diameter stenosis was similar, the residual stenosis was significantly less, both in the primary vessel and side branch, after NDI compared to balloon angioplasty. The procedure was successful in 96.6 percent patients treated with NDI and 83.3 percent with balloon angioplasty (p < 0.01) with relief of obstruction in both branches without any major complications. Freedom from subsequent coronary events in the form of angina, myocardial infarction, PTCA, bypass graft surgery of death was significantly more, both at 6 months (92% versus 65.6%, p < 0.001) and 12 months (81.8% versus 53.1%, p < 0.001) in the group of patients treated with NDI compared to balloon angioplasty. It is, therefore, concluded that NDI including DCA, rotablation and elective stenting are associated with higher rate of success, lesser complications and better event-free survival in comparison to balloon angioplasty for treatment of true bifurcation stenoses.     

Isolation process dependence of channel mobility in thin-film SOIdevices

Degradation of NMOS and enhancement of PMOS I-V characteristics are found to be dependent on specific isolation processes in thin-film SOI devices. These variations are due to mobility decrease in NMOS and increase in PMOS, which can be attributed to the isolation-process-related compressive strain of the silicon film. Magnitudes of mobility variation as high as 40% are observed in the affected SOI devices     

Protein-induced vertical lipid dislocation in a model membrane system: spin-label relaxation studies on avidin-biotinylphosphatidylethanolamine interactions

The change in vertical location of spin-labeled N-biotinyl phosphatidylethanolamine in fluid-phase dimyristoyl phosphatidylcholine bilayer membranes, on binding avidin to the biotinyl headgroup, has been investigated by progressive saturation electron spin resonance measurements. Spin-labeled phospholipids were present at a concentration of 1 mol%, relative to total membrane lipids. For avidin-bound N-biotinyl phosphatidylethanolamine spin-labeled on the 8 C atom of the sn-2 chain, the relaxation enhancement induced by 30 mM Ni2+ ions confined to the aqueous phase was 2.5 times that induced by saturating molecular oxygen, which is preferentially concentrated in the hydrophobic core of the membrane. For phosphatidylcholine also spin-labeled at the 8 position of the sn-2 chain, this ratio was reversed: the relaxation enhancement by Ni2+ ions was half that induced by molecular oxygen. In the absence of avidin, the enhancement by either relaxant was the same for both spin-labeled phospholipids. For a double-labeled system, in which both N-biotinyl phosphatidylethanolamine and phosphatidylcholine were spin-labeled on the 12 C atom of the sn-2 chain, the relaxation rate in the absence of avidin was greater than that predicted from linear additivity of the corresponding singly labeled systems, because of mutual spin-spin interactions between the two labeled lipid species. On binding of avidin to the N-biotinyl phosphatidylethanolamine, this relaxation enhancement by mutual spin-spin interaction was very much decreased. These results indicate that, on binding of avidin to the lipid headgroup, N-biotinyl phosphatidylethanolamine is lifted vertically within the membrane, relative to the phosphatidylcholine host lipids. The specific binding of avidin to N-biotinyl phosphatidylethanolamine parallels the liftase activity proposed for activator proteins associated with the action of certain gangliosidases.     

Space charge limited conduction in a-Ge22Se68M10 (M = Cd,ln,Pb,Te)

The present paper reports the measurements on space charge limited conduction in vacuum evaporated amorphous thin films of Ge₂₂Se₇₈ and Ge₂₂Se₆₈M₁₀ (M = Cd,In, Pb, and Te). Current, at high fields (~ 10⁴ V/cm), could be fitted to the theory of space charge limited conduction in case of a uniform distribution of localized states in the mobility gap of these materials. The results indicate that the density of localized states increases when a third element is incorporated in binary Ge₂₂Se₇₈ alloy. The increase could be related to the electronegativity difference between the third element and seleneum in Ge-Se system.     

Effect of heat treatment on electron traps in n-type GaAs

Annealing of bulk and vapor phase epitaxial (VPE) n-type GaAs at about 600°C for one hour in an apparatus of fused quartz (GE 204 or vitrosil) is seen to cause considerable reduction in the free electron concentration (N_S) and the commonly observed 0.85 eV electron traps (N_T) in these materials. Heating at elevated temperatures in the same environment causes an n-type sample to convert to p-type. The reduction in N_S and N_T is found to be considerably smaller for comparable heat treatments in a vacuum system free from quartz. It is suggested that the observed reduction is caused by in-diffusion of impurities like Cu and Li which are present in the types of quartz used in the experiments.     

Differential scanning calorimetric investigation of curing of resins formed from furfural and various phenols

Curing reactions of adequately characterized phenol-furfural, o-chlorophenol-furfural, P-chlorophenol-furfural and p-tert-butyl phenol-furfural resins with hexamine were studied by differential scanning calorimetry. The data are analyzed by appropriate empirical relations with a view to examining their applicability to the present sets of data and to estimating kinetic parameters of the curing reactions.     

Performance degradation in fast frequency-scanned circular arrays

The performance deterioration that sets is when a circular array is scanned fast using the method of frequency scanning is considered. The high-speed effects are a loss in the main-beam amplitude and a change in sidelobe level. However, in contrast with the case of a linear array, the circular array is relatively free from variations in the beamwidth or generation of spurious frequencies. Specific examples in radar and sonar are discussed.     

Structural design sensitivity analysis with general boundary conditions: Static problem

This paper presents and analyses methods for design sensitivity analysis of static response for structural systems when general boundary conditions are used during the analysis phase. The design sensitivity analysis methods where the boundary conditions are used to reduce the equilibrium equation have been presented earlier. In such procedures, the reduced stiffness matrix is non-singular. This fact is used to show differentiability of the displacement vector. When reduction procedures are not used, the global structural stiffness matrix may be singular. In such a case, differentiability of the displacement vector may be questionable. However, it is shown that the displacement vector is still differentiable. Several forms of the structural design sensitivity equations are presented. Although these equations are derived with Lagrange multiplier treatment of general boundary conditions, it is shown that they are applicable with any treatment of general boundary conditions. For example, they can also be used with co-ordinate reduction schemes. Therefore, design sensitivity analysis can be carried out with any existing finite element analysis computer code. Moreover, the procedures presented can be used to calculate sensitivity of a force of constraint can that is desired. The formulations are kept quite general such that design dependent boundary conditions can be routinely treated. An example is used to illustrate the procedures.