Transition from Arrhenius to non-Arrhenius temperature dependence of structural relaxation time in glass-forming liquids: continuous versus discontinuous scenario.

The temperature dependences of α relaxation time τ(α)(T) of three glass-forming liquids (salol, o-terphenyl, and α-picoline) were investigated by a depolarized light scattering technique. A detailed description of τ(α)(T) near T(A), the temperature of the transition from the Arrhenius law at high temperatures to a non-Arrhenius behavior of τ(α)(T) at lower temperatures, was done. It was found that this transition is quite sharp. If the transition is described as switching from the Arrhenius law to the Vogel-Fulcher-Tammann law, it occurs within the temperature range of about 15 K or less. Most of the known expressions for τ(α)(T) cannot describe this sharp transition. Our analysis revealed that this transition can be described either as a discontinuous transition in the spirit of the frustration-limited domain theory [D. Kivelson, G. Tarjus, X. Zhao, and S. A. Kivelson, Phys. Rev. E 53, 751 (1996)], implying a phase transition, or by a phenomenological expression recently suggested [B. Schmidtke, N. Petzold, R. Kahlau, M. Hofmann, and E. A. Rössler, Phys. Rev. E 86, 041507 (2012)], where the activation energy includes the term depending exponentially on temperature.

Temperature dependence of the Landau-Placzek ratio in glass forming liquids.

Here, we studied Rayleigh-Brillouin light scattering in ten different glass-forming liquids (α-picoline, toluene, o-toluidine, ethanol, salol, glycerol, dibutyl phthalate, o-terphenyl, propylene carbonate, and propylene glycol). For each of these liquids it was found that the Landau-Placzek ratio is in a good agreement with the theory at high temperatures and significantly exceeds the theoretical prediction below a certain temperature. Transition between the two temperature regimes occurs near T(A), where T(A) is crossover point from an Arrhenius-like to a non-Arrhenius behavior for the α-relaxation time dependence on temperature. Increase of the Landau-Placzek ratio relative to the theoretical prediction below T(A) seems to be the universal feature of glass-formers. We suggest that formation of locally favored structures in liquids below T(A) causes observed excess of the Landau-Placzek ratio.

Rayleigh-Brillouin light-scattering study of a simple glass former: evidence of locally favored structures.

The Rayleigh-Brillouin light scattering is studied in the glass-forming picoline with emphasis to the temperature dependence of the Landau-Placzek ratio. It was found that the Landau-Placzek ratio is in good agreement with the theoretical prediction at T>T(A), where TA is the temperature of transition from an Arrhenius-like to a non-Arrhenius behavior for the α-relaxation time dependence on temperature. Below T(A) the Landau-Placzek ratio exceeds significantly the theoretical prediction. The finding is interpreted as the evidence of the locally favored structures, which presence in an equilibrium glass-forming liquid below T(A).

[Development of enzyme immunoassay for the herbicide chlorsulfuron]. / Rasrabotka immunofermentnykh metodov opredeleniia gerbitsida khlorosul'furona.

Antibodies against the herbicide chlorsulfuron have been raised and characterized. Enzyme immunoassays (EIAs) for chlorsulfuron, involving labeled antigen or labeled antibodies, have been developed. The kinetics of antigen-antibody interactions in the EIA systems developed has been studied. Both systems exhibit equal sensitivity (1 ng/ml). The values of the coefficient of variation (CV), determined within the range of chlorsulfuron concentrations 1-100 ng/ml to be measured by the systems, are not in excess of 8%. The possibility of using glucose oxidase as a label in EIAs for chlorsulfuron has been demonstrated. Lack of cross-reactivity with a series of sulfonyl- and arylurea derivatives and triazines makes it possible to recommend the EIA systems developed for chlorsulfuron determination in the environment.

[Thyroid pathology in the population living in regions with a high technogenic load]. / Tireoidnaia patologiia u naseleniia, prozhivaiushchego v raionakh s vysokoi tekhnogennoi nagruzkoi.

Epidemiologic studies helped to disclose peculiarities of thyroid diseases prevalence in several districts of Rostov Province. High prevalence of thyroid diseases appeared to be proportional to degree of anthropogenic accumulation of industrial waste in the area. Intensity of the prevalence was independent on iodine deficiency. The materials collected prove technogenic factors to play an important role in development of thyroid diseases, so the prophylactics should consider not only correction of iodine intake.

[Clinico-diagnostic significance of fibronectin determination in diabetes mellitus in children]. / Kliniko-diagnosticheskoe znachenie issledovaniia fibronektina pri sakharnom diabete u detei.

Immunoelectrophoresis was used to measure fibronectin content in blood plasma of 111 children with insulin-dependent diabetes mellitus and in 20 normal children. In patients with diabetes mellitus, the content of plasma fibronectin turned out to be higher depending on the disease standing, the presence of microangiopathies, and status of compensation. It has been noted that fibronectin was detectable in urine in diabetic angionephropathy.

[The effect of the type of agar on the growth of the fungus Blakeslea trispora]. / Vliianie vida agara na rost griba Blakeslea trispora.

The relationship between the type of agar used to prepare solid nutrient media and the growth of Bl. trispora strains (+)8A and (-)8A was under study. Bl. trispora culture virtually failed to grow in the media prepared with powder agar, GOST 16280-70: it died after 2-month storage with 2 reinoculations. Bl. trispora grew fairly well in culture media with white frozen lamellar agar (GOST 16280-70) or with white frozen microbiologic agar, GOST 17206-71; the characteristic features of the culture were preserved after 10 monthly reinoculations.

[The fibronectin level in children with diabetes mellitus]. / Soderzhanie fibronektina pri sakharnom diabete u detei.

A study was made of the level of fibronectin in 42 pediatric patients with insulin dependent diabetes mellitus. Blood plasma fibronectin was determined by an immunoturbidometric method. A raised concentration of fibronectin was established in patients with a period of disease over 5 yrs., in decompensation of 3rd degree, and the presence of microangiopathies.