Some analogues of smith's determinant

We calculate the determinants of the greatest common divisor (GCD) and the least common multiple (LCM) matrices associated with an arithmetical function on gcd-closed and lcm-closed sets. We also consider some unitary analogues of these determinants.     

Studies on the reaction of 2-aminoacetophenone with thiophosgene

The reaction of 3- and 4-aminoacetophenone with thiophosgene in a chloroform-water-calcium carbonate mixture at room temperature results in good yields of the related, known isothiocyanates. At first, however, we failed in all our attempts to produce 2-isothiocyanatoacetophenones with this reaction. Closer inspection of the reaction showed, that the product distribution depends upon the concentration of hydrogen ions pro-ducted and on the reaction time. When the reaction was followed with thin-layer chromatography, it was observed that the isothiocyanates formed first. In the further course of the reaction, they were converted to the 4-methylene-2-oxo-3,1-benzothiazines by the action of protons. The final products of the reaction were the 4-(3,1-benzothiazin-4-yl)-methylene-3,1-benzothiazines, formed from the monomer in a dimerization process. Depending upon the time the protons were removed from the reaction mixture, different products could be isolated.     

The Quality of Statistical Reporting and Data Presentation in Predatory Dental Journals Was Lower Than in Non-Predatory Journals

Proper peer review and quality of published articles are often regarded as signs of reliable scientific journals. The aim of this study was to compare whether the quality of statistical reporting and data presentation differs among articles published in ‘predatory dental journals’ and in other dental journals. We evaluated 50 articles published in ‘predatory open access (OA) journals’ and 100 clinical trials published in legitimate dental journals between 2019 and 2020. The quality of statistical reporting and data presentation of each paper was assessed on a scale from 0 (poor) to 10 (high). The mean (SD) quality score of the statistical reporting and data presentation was 2.5 (1.4) for the predatory OA journals, 4.8 (1.8) for the legitimate OA journals, and 5.6 (1.8) for the more visible dental journals. The mean values differed significantly (p < 0.001). The quality of statistical reporting of clinical studies published in predatory journals was found to be lower than in open access and highly cited journals. This difference in quality is a wake-up call to consume study results critically. Poor statistical reporting indicates wider general lower quality in publications where the authors and journals are less likely to be critiqued by peer review.     

Accurate tracer diffusion coefficients of Na+ and Cl− ions in dilute aqueous sodium chloride solutions measured with the closed capillary method

A simple and absolute closed capillary method is introduced for measuring tracer diffusion coefficients in liquids with both - and -active tracers. In this method a narrow capillary is partially filled with a labelled solution and an unlabelled solution is used to fill the rest of the capillary. The diffusion coefficient is obtained from the time dependence of the monitored activity when the length of the capillary is known. The method has been tested by remeasuring the tracer diffusion coefficients of²²NaCl and Na³⁶Cl for solutions covering a wide range of total NaCl concentration. The average precision of the measurements was about 0.3%. The results obtained for Na³⁶Cl tracer diffusion are in good agreement with the data found in literature. The²²NaCl tracer diffusion coefficients that were measured in dilute solutions agree well with those obtained using the continuous open-ended capillary method but differ from results for solutions between 0.1 and 1M obtained with the diaphragm cell method.     

Preparation of multilayer plasma protein films on silicon by EDC/NHS coupling chemistry

Crosslinked multilayer protein films were prepared from fibrinogen, albumin, IgG, a combination of fibrinogen and catalase, and blood plasma on silicon by ethyl-dimethyl-aminopropylcarbodiimide and N-hydroxy-succinimide coupling chemistry. The 4–70 nm thick films were placed in blood plasma and the additional protein deposition measured by null ellipsometry after 5 or 60 min of incubation. The activation of the complement system and intrinsic pathway of coagulation were indicated through the subsequent binding of anti-C3c, anti-C3d, anti-properdin and anti-HMWK on top of the surface bound blood plasma. The proportion of Annexin V, Propidium Iodide and 4,6-diamidino-2-phenylindole positive cells, and the secretion of tumor necrosis factor (TNF-) and interleukin-10 (IL-10) were analysed in a monocyte culture. The results show that well known protein coupling techniques can be used for the preparation of protein layers with well controlled thickness. The layers possess low contact activation of blood plasma and induce different release of TNF- and IL-10 in monocyte cultures.     

Application of partial least-squares modelling in the optimization of a waste-water treatment plant

The partial least-squares method was applied to data collected at a municipal waste-water treatment plant to estimate the relationship between the process parameters and effluent quality. The main reason for poor treatment efficiency was the so-called bulking phenomemon of the activated sludge. The PLS model of the data presenting a normal period of operation and the bulking period thereafter showed that high temperature and decreasing concentrations of carbon and phosphorus contributed to the bulking state.     

Adsorption of albumin and IgG to porous and smooth titanium

The possibility to load submicrometer porous titanium surfaces with relatively small proteins, albumin and immunoglobulin G (IgG) was investigated. The loading ability is of interest due to the possibility of slow release of molecules from biomaterial surfaces, and may be important for the manipulation of wound healing around prostheses. Iodine-125 (125I) labeled albumin and IgG were adsorbed onto smooth and to porous titanium with a pore diameter of 200-300 nm. The smooth and porous surfaces were divided into three groups: hydrophilic, hydrophobic, or to amine-terminated silane (3-aminopropyltriethoxysilane) that bound proteins via glutaraldehyde. The protein solution pH and protein concentrations were varied, and the adsorption experiments made without or in the presence of calcium and magnesium ions. The adsorbed amounts were quantified with a gamma counter. Two to eleven times more proteins adsorbed onto porous than smooth surfaces and the adsorbed amounts increased with increasing protein concentration (0.1-10 mg/ml) during a constant incubation time. The elutability by sodium dodecyl sulphate (SDS) was incomplete on porous surfaces.     

Glycerol monooleate-blood interactions

In the present study the initial blood compatibility of glycerol monooleate (GMO)-coated surfaces was evaluated after deposition to surfaces and in bulk. The model surface was silica onto which multiple layers of fibrinogen or human serum albumin (HSA) was immobilized. The protein-coated surfaces were subsequently dip-coated in GMO in ethanol and used for blood plasma and whole blood experiments. The characterization methods included null ellipsometry, scanning electron microscopy, imaging of coagulation, hemolysis test and whole blood coagulation time by free oscillation rheometry. The results showed a GMO film thickness of approximately 350 A (approximately 4 microg/cm(2)) upon dip-coating in ethanolic solution. A major part of the deposited layer detached in aqueous solutions, especially during shear conditions. The coagulation time on GMO was significantly prolonged compared to that on HSA coated silica. Whole blood tests showed that GMO is a very weak hemolytic agent. Deposited GMO detached easily from surfaces upon rinsing or shearing, although a stable layer with undefined phase structure and a thickness of 50-70 A remained on HSA and fibrinogen precoated surfaces. This indicates that GMO has stronger adhesive forces to its substrate compared to the cohesive forces acting within the bulk GMO. The ability of GMO to detach from itself and tentatively form micelles or lipid bilayers when subjected to flowing blood may be of use in extravascular applications. It is concluded that GMO results in weak blood activation, and the material may in spite of this be suitable in selected biomaterial applications, especially as a biosealant and in colloidal dispersions.