Instrumented Force Platform for Postural Sway Studies

A force platform has been developed, which is capable of measuring postural sway in humans in two orthogonal directions. For each direction, output data consist of total average sway in two frequency bands centered on 0.57 and 2.9 Hz. The device is suitable for use in research or in a clinical setting.     

In Vitro Bioactivity Behavior of Some Borophosphate Glasses Containing Dopant of ZnO,CuO or SrO Together with their Glass-Ceramic Derivatives and their Antimicrobial Activity

Silicon - Glasses based on the soda lime borophosphate system together with samples doped with SrO, ZnO or CuO were prepared. Glass – ceramic derivatives were prepared by controlled thermal...     

High-molecular-mass and low-molecular-mass kininogens block plasmin-induced platelet aggregation by forming a complex with kringle 5 of plasminogen/plasmin

We have previously demonstrated a low-affinity (0.8 microM, non-covalent complex formation between high-molecular-mass kininogen (HK) and plasminogen (Plg) which prevented Plg interaction with glioma and endothelial cells. We have now extended our previous observations by exploring the potential complex formation between Plg and low-molecular-mass kininogen (LK) and between LK and HK with Plg cleaved with human neutrophil elastase (HNE). Plg cleavage by HNE (PlgHNE) yielded kringles 1-3, kringle 4 and mini-plasminogen. PlgHNE was subjected to SDS/PAGE under non-reducing conditions, followed by western blotting, and incubated with either 125I-HK or 125I-LK. Autoradiograms revealed that 125I-HK bound to miniplasminogen and to kringles 1-3 but not to kringle 4 and the presence of 10 mM 6-aminohexanoic acid (Ahx) disrupted only the interaction with kringles 1-3. In contrast, 125I-LK bound to miniplasminogen but not to kringles 1-3 or 4 and Ahx had no effect at all. The complex formation of either HK (0.67 microM) or LK (3 microM) with Plg (1.5 microM) did not affect its conversion to plasmin by tissue plasminogen activator (t-PA) (10 U/ml) in the presence of a tissue plasminogen stimulator (0.14 microM). However, the rate of conversion of plasminogen to plasmin by t-PA was affected when platelets were added to the reaction mixture. Since HK (0.83 microM) has been shown to inhibit plasmin-induced platelet aggregation, we investigated whether this inhibitory property is found within the heavy chain shared by HK and LK. We found that LK inhibited plasmin-induced platelet aggregation, but a 4-fold molar excess was required when compared to HK. Compared to plasmin, 3-5-fold molar excess of miniplasmin is required to induce platelet aggregation, indicating the important role of kringles 1-3 for plasmin interactions with these cells. These results indicate that HK and LK-mediated inhibition of plasmin-induced platelet aggregation is likely due to complex formation with kringle 5 without interfering with plasmin's active site. We found an additional interaction between HK and kringles 1-3 enhancing the inhibitory effect, presumably by interfering with plasmin's interaction with platelets. This HK and LK-associated modulation of plasmin-induced platelet aggregation may serve as a template to develop synthetic peptides as novel therapeutic agents to prevent some of the plasmin-associated thrombocytopenia seen during thrombolytic therapy.     

Evaluation of the DRM and the Time for Preventive Maintenance for Aging Software

An attempt to capture software aging and specify when to do preventive maintenance (PM) is presented in this paper. A composite measure termed the DRM, Deteriorating Response Measure, is defined. It is based on the analysis of the deteriorating speed of the software against time and load. This speed is characterized as follows: (1) It decays with increased load. (2) It does not increase again when the load decreases, this indicates loss of elasticity. The DRM is mathematically formulated based on a queueing system model.Specifying when to do preventive maintenance depends on the decision maker's perspective of the manifestation of aging. It is tried here to formalize this dependence. Three degrading performance metrics are defined for a DRM: (1) Decaying restored speed value. (2) Increasing speed offset ratio (recoverability index). (3) Increasing operation interval offset. These metrics can be used singly or aggregately in a DRM to specify when to do preventive maintenance. Results of model testing are also shown.This work can be part of an on-line procedure that calculates performance indexes for a server type software system like a web browser, an operating system, a database, and helps in the decision to do preventive maintenance for aging software.     

Effect of hydrothermal treatment and ammonium ion incorporation in platinum-mordenite catalysis for n-hexane hydroconversion

Hydroconversion of n-hexane was studied on catalysts containing 0.25% Pt supported on H-mordenite (H-M) and NH₄-M. The H-M containing catalysts were Pt/H-M, Pt on steamed H-M (Pt/St H-M) and steamed Pt/H-M (StPt/H-M), whereas the NH₄-M containing catalysts were Pt/NH₄-M and StPt/NH₄-M. Steam-treatment of H-M containing catalysts enhanced the hydroconversion activity, whereas such treatment decreased the activity of the Pt/NH₄-M catalyst. The diffusion resistance parameter, i.e., the Thiele modulus, Φ_L, estimated for the reaction on the catalysts under study was found to increase with the increase in the catalytic activity, and both were found to decrease in the order:

Pt dispersion in the zeolite was not comparable with the catalytic activities of the H-M containing catalysts. The higher activity of the Pt/NH₄-M catalyst could be attributed to a higher Pt dispersion in the zeolitic channels, higher strength of the acid sites (determined by temperature programmed desorption (TPD) of ammonia) and higher diffusion limitation of the reactant in the catalyst pores.     

Polarography of eosin and erythrosin in solutions of varying pH at the DME

The polarographic behaviour of eosin and erythrosin in buffer solutions of pH 4–11 is discussed. The observed waves are assigned to the reduction of furan and pyrone rings of the molecule of erythrosin at pH 4–11 and for eosin at pH ?7. The nature of the waves is also investigated. In alkaline media the electrode reaction is essentially diffusion controlled whereas at pH < 8 adsorption of the reduction products contributes in the electrodes process.