Utility of Platelet Endothelial Cell Adhesion Molecule 1 in the Platelet Activity Assessment in Mouse and Human Blood

In our previous study, we introduced the platelet endothelial cell adhesion molecule 1 (PECAM-1)/thrombus ratio, which is a parameter indicating the proportion of PECAM-1 in laser-induced thrombi in mice. Because PECAM-1 is an antithrombotic molecule, the higher the PECAM-1/thrombus ratio, the less activated the platelets. In this study, we used an extracorporeal model of thrombosis (flow chamber model) to verify its usefulness in the assessment of the PECAM-1/thrombus ratio in animal and human studies. Using the lipopolysaccharide (LPS)-induced inflammation model, we also evaluated whether the PECAM-1/thrombus ratio determined in the flow chamber (without endothelium) differed from that calculated in laser-induced thrombosis (with endothelium). We observed that acetylsalicylic acid (ASA) decreased the area of the thrombus while increasing the PECAM-1/thrombus ratio in healthy mice and humans in a dose-dependent manner. In LPS-treated mice, the PECAM-1/thrombus ratio decreased as the dose of ASA increased in both thrombosis models, but the direction of change in the thrombus area was inconsistent. Our study demonstrates that the PECAM-1/thrombus ratio can more accurately describe the platelet activation status than commonly used parameters such as the thrombus area, and, hence, it can be used in both human and animal studies.     

Polarization-dependent angular-optical reflectance in solar-selective SnOx:F/Al2O3/Al reflector surfaces

Polarization-dependent angular-optical properties of spectrally selective reflector surfaces of fluorine-doped tin oxide (SnOx:F) deposited pyrolytically on anodized aluminum are reported. The angular-reflectance measurements, for which both s- and p-polarized light are used in the solar wavelength range 0.3-2.5 microm, reveal strong spectral selectivity, and the angular behavior is highly dependent on the polarizing component of the incident beam, the total film thickness, and the individual thickness of the Al2O3 and the SnO2:F layers. The anodic A12O3 layers were produced electrochemically and varied between 100 and 205 nm in thickness. The SnOx:F films were grown pyrolytically at a temperature of 400 degrees C with film thicknesses varying in the range 180-320 nm. The reflectors were aimed at silicon solar cells, and good spectrally selective reflector characteristics were achieved with these thinly preanodized, SnOx:F/Al samples; that is, high cell reflectance was obtained for wavelengths below 1.1 microm and low thermal reflectance for wavelengths above 1.1 microm, with the best samples having values of 0.80 and 0.42, respectively, at near-normal angles of incidence. This corresponds to an anodic layer thickness of 155 nm. Both the angular calculations and the experimental measurements show that the cell reflectance is relatively insensitive to the incidence angle, and a low thermal reflectance is maintained up to an angle of approximately 60 degrees.     

Sulphur-containing polyacrylates. III: UV-induced copolymerization of methyl methacrylate with some dimethacrylates containing ether or thioether linkage

The UV-induced copolymerization of methyl methacrylate (MM) with 2,2′-thiobisethanol dimethacrylate (TEDM) and MM with 2,2′-oxybisethanol dimethacrylate (OEDM) was investigated for a wide range of the diester content (6-80 mol%) in the initial mixture. The influence of the feed composition on the course of copolymerization was determined. It was found that there exists a minimum on the plot of maximum yield of soluble copolymer versus diester content at a diester content of 30 mol%. The total copolymer yields were lower in the case of mixtures containing TEDM comonomer. Determination of the reactivity ratios gave the following values: for MM + TEDM r_a = 0·21, r_b = 4·59 and for MM + OEDM r_a = 0·55. r_b = 4·42. A possible explanation of the results obtained is discussed.     

Examples of peptide-peptoid hybrid serine protease inhibitors based on the trypsin inhibitor SFTI-1 with complete protease resistance at the P1-P1' reactive site

Research in the field of protease inhibitors is focused on obtaining potent, specific and protease-resistant inhibitors. To our knowledge, there are no reports in the literature that consider the application of N-substituted glycine residues (peptoid monomers) for the design of peptidomimetic protease inhibitors. We hereby present the chemical synthesis and kinetic properties of two new analogues of the trypsin inhibitor SFTI-1 modified at the P1 position. Substitution of Lys5 in SFTI-1 by N-(4-aminobutyl)-glycine and N-benzylglycine, which mimic Lys and Phe, respectively, made these analogues completely protease-resistant at their P1-P1' reactive sites. The analogues synthesised appeared to be potent inhibitors of bovine beta-trypsin and alpha-chymotrypsin. These noncovalent, competitive and selective peptide-peptoid hybrid (peptomeric) inhibitors might open the way to targeting unwanted proteolysis.     

Identification of the major sources contributing to PM2.5 observed in Toronto

The chemical composition of Toronto PM2.5 was measured daily from Feb 2000 to Feb 2001, and source apportionment was undertaken using positive matrix factorization (PMF). In Toronto, PM2.5 levels were influenced both by local urban activities and also by regional-scale transport. Although several PMF solutions were possible, an eight-source model for explaining the observed Toronto PM2.5 was found to provide realistic results and interesting insights into sources. The four main sources were coal combustion related to regional transport and secondary sulfate (26%), secondary nitrate related to both local and upwind sources of NOx and NH3 (36%), secondary organic aerosols (SOA) formed from a variety of precursor organic emissions (15%), and motor vehicle traffic (10%). The other detectable sources were road salt (winter) and three types of primary PM2.5 hypothesized to be associated with smelters, coal and oil combustion, industry, and local construction. Overall, motor vehicle-related emissions (including road salt and nitrate) were estimated to be responsible for about 40% of the PM2.5. In the summer, the SOA mass was estimated to contribute approximately 20% to the PM2.5. Inclusion of water-soluble, low-molecular-weight organic acids led to identification of this component, thus providing a significant improvement in PMF's ability to resolve sources. Without organic acid measurements the SOA portion of the observed PM2.5 was assigned to the secondary coal component, increasing its contribution and resulting in a source profile with an unrealistic amount of organic mass. This suggests that in the northeastern part of North America, there are physical and/or chemical processes that lead to close interaction between secondary organic and inorganic aerosols.     

Computer mouse use in two different hand positions: exposure,comfort, exertion and productivity

The aim of this study was to determine whether there are differences in exposure, comfort, exertion and productivity between a neutral and a pronated hand position when using a computer mouse. Nineteen experienced VDU workers performed a standardised text editing task with each mouse hand position. The wrist positions and movements in the working arm were registered by an electrogoniometer and the muscle activity in the shoulder, two extensors in the forearm and the first dorsal interossei (FDI) was registered by electromyography. The subjects rated perceived exertion and comfort in work with each mouse hand position. Work with the neutral hand position, compared to the pronated, gave a decreased muscle activity in the extensors of the forearm and in the FDI and a trend indicating a decrease in the frequency of deviation movements in the wrist. At the same time, the subjects showed a decreased productivity and they rated less comfort in work with the neutral hand position.     

The use of information technology among young adults--experience, attitudes and health beliefs

The aim of this study was to explore attitudes, coherence and health beliefs among young adults, related to their use and experience of information technology (IT). A qualitative approach was used and the data were collected through individual thematised interviews with 25 young IT users, aged 18–24. The interviews were analysed in line with the grounded theory method with a constructivist approach. The main findings were the young adults’ experience of the two sides of being social, efficient and independent here and now. They described almost unlimited opportunities in connection with IT, but they also had misgivings, and perceived risks regarding IT use. Feelings of freedom and being efficient were countered by feelings of restrictions on living space and of intangibility. Knowledge concerning these attitudes, coherence and health beliefs can be considered when designing epidemiological and ergonomic studies aimed at risk identification.     

Biochemical evaluation of digoxin dosage in patients with heart failure

The investigations were carried out in 56 patients aged 54 to 84 years, treated with a supporting dosage 0.25 mg of digoxin because of chronical insufficiency of the heart, according to the NYHA classification II and III degree, in whom the functions of liver and kidneys have not been ascertained. A fourfold determination of digoxin concentrations in the blood was established in the time of distribution balance. From among the examined patients three groups were separated: receiving the drug chronically at 8.00 a.m. (group A), receiving it at 8.00 p.m. (group B) and group C, for which the sacral method was used. Depending on medical indications the patients received during the examination other drugs. In group C the therapy was limited to diuretic drugs. In no clinical symptoms of digitalism could be observed. Subtherapeutic levels of digoxin (< 0.8 ng/ml) were found in the three groups on an average in 50% of the patients. The high percentage of patients with nontherapeutic concentration in blood serum confirms once more, that treatment with digoxin without checking their concentration in the serum does not give the certainty of suitable dosage. The results of the studies show that the optimalization of digoxin therapy from the point of pharmacological view should be based on a penetrating estimation of the whole of the clinical image, the checking of the image with the help of the concentration determinations of the drug.     

Voltammetric investigation of the two step reduction process of hydrogen peroxide in alkaline hydroxide solutions on HMDE

The voltammetric behaviour of hydrogen peroxide has been studied at the hmde in alkaline medium. It has been confirmed that the first of the two reduction peaks of hydrogen peroxide is catalytic in nature; traces of ferric iron act under these conditions as a catalyst. In thoroughly purified potassium hydroxide solutions the height of this peak decreases and it can be also completely eliminated, even in the presence of Fe(III), if some agents capable of forming complexes with Fe(III) are added to a solution. The rate constant of the catalytic reaction proceeding between the hydroxo complex of Fe(II) and hydrogen peroxide in 1 M potassium hydroxide solution was estimated to be 5.6 × 10⁹ mol^?1 1.s^?1.     

Two flow network simplification algorithms

Flow network simplification can reduce the size of the flow network and hence the amount of computation performed by flow algorithms. We present the first linear time algorithm for the undirected network case. We also give an O(|E|∗(|V|+|E|)) time algorithm for the directed case, an improvement over the previous best O(|V|+²|E|log|V|) time solution. Both of our algorithms are quite simple.