Water pollution in Ukraine: the search for possible solutions

In Ukraine, average and maximum concentrations of certain pollutants in inland water bodies are unacceptably high, while the number of heavy pollution accidents (one‐out effluent discharges capable of causing health hazards) is increasing. Meanwhile, the transition from a centrally planned to a free market economy is associated with severe economic downturn and a marked industrial decline. However, no comprehensive analyses related to issues linking water pollution and socio‐economic situation during the period 1991–2003 have been done. It is considered unlikely that much can be achieved to improve water quality, at the state level, in the near future. Some improvement can be achieved through changes in the system of pollution control and in public attitude, as well as obtaining relevant expertise and funds from abroad.     

Simple purification methods for an alphagalactose-specific antibody from chicken eggs

For many applications avian antibody from egg yolk (IgY) offers advantages over the well-known mammalian antibodies. Different experimental techniques for the purification of IgY from chickens immunized with an alphagalactose-containing antigen (alphaGal-trisaccharide) were compared. These included ammonium sulfate precipitation, filtration with diatomaceous earth, treatment with deoxycholate, and thiophilic and affinity chromatography. Samples were tested for overall purity, protein and lipid content, and specific activity. Evaluated on the basis of these results and the simplicity of the process, the favored purification method is ammonium sulfate precipitation of diluted egg yolk directly followed by affinity chromatography. The high lipid content of IgY preparations is greatly reduced by either thiophilic or affinity chromatography. Affinity purification of ammonium sulfate precipitated material resulted in anti-alphaGal-trisaccharide IgY preparations with approximately 1% of the original protein content but approximately 100-fold higher specific activity for the alphaGal-trisaccharide epitope.     

Experimental Investigation of Friction Factor in the Transition Region for Water Flow in Minitubes and Microtubes

A systematic and careful experimental study of the friction factor in the transition region for single-phase water flow in mini- and microtubes has been performed for 12 stainless-steel tubes with diameters ranging from 2083 μ m to 337 μ m. The pressure drop measurements were carefully performed by paying particular attention to the sensitivity of the pressure-sensing diaphragms used in the pressure transducer. Experimental results indicated that the start and end of the transition region were influenced by the tube diameter. The friction factor profile was not significantly affected for the tube diameters between 2083 μ m and 1372 μm. However, the influence of the tube diameter on the friction factor profile became noticeable as the diameter decreased from 1372 μ m to 337 μm. The Reynolds number range for transition flow became narrower with decreasing tube diameter.     

High hydrostatic pressure treatment of finfish to inactivate Anisakis simplex

High hydrostatic pressure has been demonstrated to be a useful technique for treating food to reduce the number of pathogenic organisms and to extend shelf life. Most research in this area has focused on bacteria. However, a concern in the sashimi (raw fish) industry is that nematode worms such as Anisakis simplex occur naturally in cold-water marine fish. The objectives of this research were to perform a pilot study to determine the effect of high hydrostatic pressure on the viability of Anisakis simplex larvae, commonly found in king salmon and arrowtooth flounder, and to evaluate the effects of high hydrostatic pressure on the color and texture of the fish fillets. Pieces of fish (ca. 100 g per bag) containing 13 to 118 larvae were exposed to pressures of up to 80,000 lb/in2 (552 MPa) for up to 180 s. The times and pressures required to kill 100% of the larvae were as follows: 30 to 60 s at 60,000 lb/in2 (414 MPa), 90 to 180 s at 40,000 lb/in2 (276 MPa), and 180 s at 30,000 lb/in2 (207 MPa). For all salmon treatments that killed 100% of the larvae, a significant increase in the whiteness of the flesh was observed. Although high hydrostatic pressure was effective in killing A. simplex larvae in raw fish fillets, its significant effect on the color and overall appearance of the fillet may limit its application to the processing of fish for raw-fish markets.     

Shared book reading: When and how questions affect young children's word learning.

Shared book reading, and the conversation that accompanies it, can facilitate young children's vocabulary growth. To identify the features of extratextual questions that help 3-year-olds learn unfamiliar words during shared book reading, two experiments explored the impact of cognitive demand level, placement, and an approximation to scaffolding. Asking questions about target words improved children's comprehension and production of word–referent associations, and children with larger vocabularies learned more than children with smaller vocabularies. Neither the demand level nor placement of questions differentially affected word learning. However, an approximation to scaffolding, in which adults asked low demand questions when words first appeared and high demand questions later, did facilitate children's deeper understanding of word meanings as assessed with a definition task. These results are unique in experimentally demonstrating the value for word learning of shifting from less to more challenging input over time. Discussion focuses on why a scaffolding-like procedure improves children's acquisition of elaborated word meanings. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Summarization for termination: no return!

We propose a program analysis method for proving termination of recursive programs. The analysis is based on a reduction of termination to two separate problems: reachability of recursive programs, and termination of non-recursive programs. Our reduction works through a program transformation that modifies the call sites and removes return edges. In the new, non-recursive program, a procedure call may non-deterministically enter the procedure body (which means that it will never return) or apply a summary statement.     

The dispersion of some optical properties of vitrinite

The dispersion characteristics of some optical properties of vitrinites from a number of coals of differing coal rank and type were investigated using a microscope photometer. The properties studied were air and oil reflectances, refractive index and absorption index. The technique employed involved the measurement of air and oil reflectances at a number of wavelengths in the visible spectrum for selected points on the coal, as opposed to averaging the reflectances obtained in each immersion medium for each wavelength. The values of air and oil reflectances were then used to calculate the corresponding values of refractive index (n) and absorption index (κ) using a rearrangement of Beer's equation. Smooth dispersion curves were obtained for each selected field of vitrinite using this procedure. This method was preferred to the more widely used method of calculating n and κ from the average air and oil reflectances at each wavelength, because refractive and absorption indices are non-linear functions of reflectance, which makes the arithmetic mean of the reflectances unsuitable for the calculation of n and κ. The values of all parameters for the vitrinites were found to increase towards the blue region of the visible spectrum and to increase at all wavelengths with increasing coal rank. Some negative values of κ² were obtained and the significance of these values is discussed.     

Crosslinking of mixtures of diglycidylether of bisphenol‐A with 1,6‐dioxaspiro[4.4] nonan‐2,7‐dione initiated by tertiary amines: III. Effect of hydroxyl groups on network formation

BACKGROUND: Blends of epoxy resin oligomers, diglycidylether of bisphenol‐A (DGEBA), and a bislactone, 1,6‐dioxaspiro[4.4]nonan‐2,7‐dione (s(γBL)), were anionically copolymerized using two tertiary amines as anionic initiators. Their curing rheology and gelation behaviour were studied to provide a more comprehensive knowledge of the curing of these previously studied systems. RESULTS: The activation energy for gelation was found to be similar to that previously measured using differential scanning calorimetry and appeared to increase in the presence of the bislactone. The reaction rate during copolymerization of DGEBA with s(γBL) was slower than DGEBA homopolymerization alone because the alkoxide attack on the epoxide is faster than the reaction of the carboxylate ion and the epoxy group. The effect of the initiator type on the gel conversion was small and was presumably due to differences in the kinetic chain length caused by amine regeneration from the quaternary amine. For the same initiator and at a constant ratio of DGEBA/s(γBL), an increase in the hydroxyl concentration of the DGEBA oligomer raised the gel conversion. For a DGEBA oligomer with low hydroxyl levels, an increase in the concentration of s(γBL) increased the gel conversion; however, for a DGEBA oligomer with high hydroxyl levels, increasing s(γBL) concentration decreased the gel conversion. CONCLUSION: These results are interpreted in terms of the effect of initiation rate and chain transfer rate on the kinetic chain length. The glass transition temperature of the gel was found to be controlled by the fraction of the aliphatic s(γBL) and the amount of plasticizing sol in the matrix. Copyright © 2009 Society of Chemical Industry     

The theory of transient photoconductive processes in II–VI compounds with three deep trapping levels

The transient photoconductive rise and decay processes were studied quantitatively in a typical II–VI compound by solving the rate equations on a digital computer. The calculations were based on a model with three deep trapping levels, as proposed by Rose and by Bube. A study was made of the effect of changing the concentration, position, and capture asymmetry fo these levels. We have also considered the way in which the defect centers change their role from trapping to recombination (or vice versa) as a result of free carrier concentration changes. Our work confirms previous explanations of the relation between sensitizing level properties and the steady-state superlinear behavior exhibited by II–VI photoconductors. On the other hand, a different approach appears to be necessary to account for transient phenomena. We do not believe that the position or asymmetry of the trapping levels is crucial in determining photoconductive sensitivity and response times. Instead, we find that these material properties can be predicted from a knowledge of the equilibrium and the steady-state charge concentrations. In addition, we show that the dynamic changes in the function of the deep levels from trapping to recombination, or vice versa, are the consequence—rather than the cause—of the specific way in which the photoconductive rise and decay processes occur.