Ultrasonic degradation of aqueous carboxymethylcellulose: effect of viscosity, molecular mass, and concentration

It is well established that prolonged exposure of solutions of macromolecules to high-energy ultrasonic waves produces a permanent reduction in viscosity. It is generally agreed as well and also this study proved the hydrodynamic forces to have the primary importance in degradation. According to this study the sonolytic degradation of aqueous carboxymethylcellulose polymer or polymer mixtures is mainly depended on the initial dynamic viscosity of the polymer solution when the dynamic viscosity values are in the area range enabling intense cavitation. The higher was the initial dynamic viscosity the faster was the degradation. When the initial dynamic viscosities of the polymer solutions were similar the sonolytic degradation was dependent on the molecular mass and on the concentration of the polymer. The polymers with high molecular mass or high polymer concentration degraded faster than the polymers having low molecular mass or low polymer concentration. The initial dynamic viscosities were adjusted using polyethyleneglycol.     

On generalized Fibonacci and Lucas polynomials

Let h(x) be a polynomial with real coefficients. We introduce h(x)-Fibonacci polynomials that generalize both Catalan’s Fibonacci polynomials and Byrd’s Fibonacci polynomials and also the k-Fibonacci numbers, and we provide properties for these h(x)-Fibonacci polynomials. We also introduce h(x)-Lucas polynomials that generalize the Lucas polynomials and present properties of these polynomials. In the last section we introduce the matrix Q_h(x) that generalizes the Q-matrix whose powers generate the Fibonacci numbers.     

A note on the exponentiality of total hazards before failure

It is well known that a univariate counting process with a given intensity function becomes Poisson, with unit parameter, if the original time parameter is replaced by the integrated intensity. P. A. Meyer (in Martingales (H. Dinges, Ed.), pp. 32–37. Lecture Notes in Mathematics, Vol. 190, Springer-Verlag, Berlin) showed that a similar result holds for multivariate counting processes which have continuous compensators. Even more is true in the multivariate case: If each coordinate process is transformed individually according to a convenient time change, the resulting Poisson processes become independent. Our aim is to show that the continuity assumption of the compensators can be relaxed and, when the jumps of the compensator become small, we obtain the independent Poisson processes as a limit. An application for testing goodness-of-fit in survival analysis is given.     

The evaporation of potassium from phlogopite

The evaporation of potassium from phlogopite was investigated by roasting phlogopite with different chemical reagents. The possible reactions between reactants and the sample at different temperatures were investigated by thermogravimetry. Gypsum, calcite, sodium chloride, activated carbon, calcium chloride and fluoride were used as chemical reactants. Similar tests were carried out by batch experiments using muffle furnace and tube oven and finally the sample mixtures were heated in a vacuum. The use of a vacuum enabled an almost complete extraction of potassium in solid state at the lowest temperature so far investigated. The structure of phlogopite was shown to be destroyed by raising the temperature. The extraction of potassium from feldspar, a sample from Lohja, Finland was also investigated.

---

Zusammenfassung Beim Abrösten von Phlogopit mit verschiedenen chemischen Stoffen wurde das Verdampfen von Kalium aus Phlogopit untersucht. Die möglichen Reaktionen zwischen der Probe und der Reaktionspartnern bei verschiedenen Temperaturen wurden mittels Thermogravimetrie untersucht. Als Reaktant wurden Gips, Kalzit, Natriumchlorid, Aktivkohle, Kalziumchlorid und -fluorid verwendet. Ähnliche Untersuchungen wurden in Reihenexperimenten mittels Muffel- und Röhrenofen und letztlich durch Erhitzen der Proben im Vakuum durchgeführt. Die Anwendung von Vakuum ermöglicht bei den niedrigsten der angewendeten Temperaturen einen fast vollständigen Auszug des Kaliums aus dem Feststoff, Durch Erhöhen der Temperatur wurde die Struktur von Phlogopit nachweislich zerstört. Die Extraktion von Kalium aus einer Feldspatprobe aus Lohja, Finnland, wurde ebenfalls untersucht.

---

. . , , , , . , , . , , . , . //.

     

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.     

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.     

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.