Ultraviolet influence on catalase activity and mineral content in eyeballs of gibel carp (Carassius auratus gibelio)

UV radiation present in the environment may induce several eye disorders including inflammation and cataract. The aim of this work was to study catalase activity and Mg, Cu, Ca and Zn contents in the eyeballs of gibel carp exposed to ecologically relevant doses of UV radiation (0.09 kJ/m2 for UV-A and 0.98 kJ/m2 for UV-B) simulated in laboratory conditions. Ultraviolet exposure resulted in significant reduction of catalase activity in the eyeballs of tested fish. Reductions in Mg, Cu and Ca contents after UV exposure were also observed. The differences in Mg and Cu levels between control and UV exposed animals were statistically significant, whereas the reduction of Ca level was insignificant. Zinc level in the eyeballs of UV-exposed fish was significantly higher than in non-irradiated specimens. The results suggest that ultraviolet radiation affects prooxidant/antioxidant balance and Mg, Cu, Zn contents in the eyes of fish living in shallow habitats. These may lead to cataract formation.     

A Compendium of Continuous Lattices in MIZAR

This paper reports on the MIZAR formalization of the theory of continuous lattices as presented in Gierz et al.: A Compendium of Continuous Lattices, 1980. By a MIZAR formalization we mean a formulation of theorems, definitions, and proofs written in the MIZAR language whose correctness is verified by the MIZAR processor. This effort was originally motivated by the question of whether or not the MIZAR system was sufficiently developed for the task of expressing advanced mathematics. The current state of the formalization – 57 MIZAR articles written by 16 authors – indicates that in principle the MIZAR system has successfully met the challenge. To our knowledge it is the most sizable effort aimed at mechanically checking some substantial and relatively recent field of advanced mathematics. However, it does not mean that doing mathematics in MIZAR is as simple as doing mathematics traditionally (if doing mathematics is simple at all). The work of formalizing the material of the Gierz et al. compendium has (i) prompted many improvements of the MIZAR proof checking system, (ii) caused numerous revisions of the the MIZAR data base, and (iii) contributed to the to do list of further changes to the MIZAR system.     

The application of solid electrolytes to the thermodynamic study of some alkaline earths silicates

Solid electrolytes based on stabilized zirconia (or thoria) cannot be used to the construction of the solid galvanic cells for the study of thermodynamic properties of the alkaline earths silicates. They become a partially electronic conductors of low chemical potentials of oxygen, as those in the coexisting alkaline earths silicate phases.It was attempted to use as the solid electrolyte a mixture of small amounts of alkaline earth fluoride in the corresponding silicate. Then, the solid galvanic cells consisting of such electrolytes were applied to the determination of the standard Gibbs free energies of formation of some magnesium, strontium and barium silicates.     

Thermal decomposition of methylene-4,4'-di(ethylphenyl-carbamate) to methylene-4,4'-di(phenylisocyanate)

During thermal decomposition of methylene-4,4'-di(ethylphenylcarbamate) (MDU), methylene-4,4'-di(phenylisocyanate) (MDI) appears to be the main product, provided that the ethanol formed in the reaction is carried away. Polycarbodiimides are the main by-products along with small amounts of 4,4'-di(aminophenyl)methane and its derivatives. Under the reaction conditions used in these studies, the latter compound together with its derivatives, reacts both with MDI and MDU. At 220-310 degrees C and a reaction time of 80-110 min, the selectivity of the MDU transformation to MDI in relation to consumed MDU is 60-87 mol.%. The selectivity of the transformation to polycarbodiimides is 7-20 mol.%, and that to amines and urea derivatives is about 1-2 mol.%.     

How ciliates manipulate their own DNA – A splendid example of natural computing

DNA computing is a novel and vivid researcharea which is genuinely interdisciplinary –computer scientists and molecular scientistscollaborate to investigate the use of DNAmolecules for the purpose of computing. DNAcomputing in vivo is the investigation ofcomputations taking place naturally in a livingcell, with the goal of understandingcomputational properties of DNA molecules intheir native environment. Gene assembly inciliates (single cell organisms) is perhaps themost involved process of DNA manipulation yetknown in living organisms. The computationalnature of this process has attracted muchattention in recent years. The resultsobtained so far demonstrate that this processof gene assembly is a splendid example ofcomputing taking place in nature, i.e., NaturalComputing. Indeed, DNA computing in vivomay be far more widespread in nature than wecurrently recognize. This paper is a tutorialon (computational nature of the) gene assemblyin ciliates, which is intended for a broadaudience of researchers interested in NaturalComputing. In particular, no knowledge ofmolecular biology is assumed on the part of themotivated reader.     

Egotism versus generalization-of-uncontrollability explanations of helplessness: Reply to Snyder and Frankel (1989).

M. L. Snyder and A. Frankel (see record 1990-09504-001) argue that our experiments (M. Kofta and G. S?dek; see record 1989-24900-001) were inadequate for testing the egotism theory of helplessness because they did not directly address the role of threat to self-esteem, the process held responsible for helplessness deficits by this theory. We reply that failure experience—the chief manipulation in these experiments—is critical for arousing threat to self-esteem. Therefore, our findings—that (a) noncontingency, not ego-threatening failure, is specifically responsible for helplessness deficits, and (b) availability of excuse for failure in the test phase augments performance deficits instead of mitigating them—call into question the validity of the egotism explanation of helplessness. We conclude that by and large, our study lends support to the original learned helplessness theory of Seligman and his associates. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The investigation of aggregate grain size effect on fracture toughness of ordinary concrete structures

The material under investigation was ordinary conerete of B 20 class, different in the sizes of coarse aggregate and water-cement ratio of the same value w/c=0.55. It was found during the tests that there were two kinds of sample cracking mechanisms. Some samples cracked at the moment of the initiation of slit (when P _Q=P _max); in others the decohesion force P _max exceeded P _Q, which was identified as a minor deflection or relative extremum of the curve. The frequency of the second type of cracking increased with the growing size of coarse aggregate grains. Together with the growth of the grain size, the angle of curve inclination also became smaller. This phenomenon can be explained by the fact that, in the process of decohesion, the aggregate grains are relocated and the system of contact between them changes, so the K _Hc depends on coarse aggregate.     

Repeated failure: A source of helplessness or a factor irrelevant to its emergence?

Tested the validity of the egotism model of human helplessness (HE). In contrast to the original theoretical approach of M. E. P. Seligman (1975) and his associates, which points to response–outcome noncontingency as the main source of HE, the egotism alternative proposes that repeated failure itself is the critical determinant of HE symptoms. Repeated failure threatens the self-esteem of the S, who supposedly engages in a least-effort strategy during the test phase of a typical learned HE study, which results in performance impairment. To examine the egotism explanation, we gave Ss noncontingent-feedback training with or without repeated failure on 5 consecutive discrimination problems. In 2 experiments, noncontingent-feedback preexposure produced HE deficits in performance on avoidance learning, whereas repeated failure appeared irrelevant to HE. This and our other findings from research are inconsistent with the egotism explanation and support instead Seligman's original proposal, in which HE is attributed to prolonged experience with noncontingency. (PsycINFO Database Record (c) 2010 APA, all rights reserved)