A distinct phase effect was observed on the formation of13NH3, H13NOx and [13N]-amide in pile-irradiated butyric-d7 acid, although the magnitude of the effect was rather smaller than that in deuterated trifluoroacetic, acetic and propionic acids previously reported. In frozen butyric-d7 acid, most of13N was found in the forms such as13NH3 (54.8±0.7%), H13NOx (26.8±0.6%). and [13N]amide (15.9±1.8%). The yields of HC13N and [13N]aminobutyric acid were only 0.6±0.3 and 1.2±0.3% even in the liquid, respectively. The scavenger effect of acetic anhydride-d6 on the formation of13NH3, H13NOx and [13N]amide was examined. In liquid and frozen carboxylic acids, the yields of13NH3 and H13NOx were proportional and inversely proportional to the number of hydrogen atoms in a target molecule in the region of the number of hydrogen from unity to eight.
Authors:A. Lichnova, I. Marova, R. Valentova and P. Matouskova
The aim of this work was to study antimutagenic and antioxidant properties of water extracts of various types of rice. Antioxidant activity, total phenolic andflavonoid contents were measured spectrophotometrically. Individual phenolics — catechins, catechin gallates, ferulic acid — were analysed by HPLC/PDA. Antimutagenic activity of rice extracts was tested using unicellular eukaryotic yeast strain Saccharomyces cerevisiae D7 the first time.Non-processed rice types contained substantially higher amount of soluble total and individual phenolics and had higher antioxidant activity than peeled rice. Parboiled rice, in which technological processing helps to maintain active substances inside the grains, exhibited also relatively high phenolic levels. The highest antimutagenic effect was proved in Indian Rice, Arborio, Jasmine Rice and Three Colours Rice independently of rice extract concentration. Because of relatively high values of phenolics and high antioxidant activity, the antimutagenic activity of these samples could be attributed to biologically active phenolics present mainly in the bran layer of whole rice grain.
A comparative study of the deuterium kinetic isotope effect in the oxidation of the deuteriated butyric acid-D7 with Cr(VI) in 85% orthophosphoric acid has been carried out.The (kHH/kDD) KIE values between 5.7 and 7.0 indicate that the tunnelling is not involved in oxidation of deuteriated aliphatic carboxylic acids with chromium trioxide in acidic media and the oxidation KIE is determined by the zero point energy difference corresponding to the C-H/C-D stretching vibrations lost in the transition state.The results were compared with the large D-KIE observed in the oxidation of butyrate-D7 with alkaline manganate caused by the simultaneous operation of zeropoint energy effect and tunnelling.
The starting point of this paper is the idea that trade unions and individual workers pay attention to wage settlements in similar sectors of the economy. The foundations of the concept of comparison wage can be found in other social sciences and also in the literature of psychological economics. Despite the fact, however, that comparison — or reference — wage enters the decision making of the union (i.e. the union utility function), the concept has not received much attention in connection with union decision making. In this paper, a union utility function is employed incorporating the concept of comparison wage. The analysis is conducted in a bargaining framework and the results show the effects on the optimal wage of important variables like comparison wage, unemployment benefit, union power and of the weight that the union places on the comparison wage.
Since the first publication of Economics of Shortage in 1980, an entire economist generation has grown up, whose members are well-versed in numerous sub-themes of the economic sciences. They find their way around the most modern methodological schools, yet they know significantly less about the workings of the social systems. To the younger generations, the socialist system, whose heritage still lives with us and whose characteristic behavioural forms and attitudes have not yet disappeared at all from the economic practices of the post-socialist countries, seems like the distant past, just like the Turkish occupation or the Austro-Hungarian Monarchy.The target audience of Kalligram Publishing House is this generation, to the majority of whom János Kornai’s works will probably come as a revelation. The years of crisis — whose end is still far off — has made even those uncertain about the workings of economic systems, who have personal experiences of the decades of socialism. Therefore, it would be quite important for them to re-read Kornai’s works written during the socialist era in order to be able to grasp the workings of economic systems through the help of balanced and objective analyses. Moving beyond the momentary shocks and nostalgias, the older ones also have a great need to evaluate the roles of the market and the state in a bias-free manner resting on a solid theoretical foundation, to realistically see the mechanisms of shortage and surplus economies. This way it is perhaps possible to avoid “going down the same river twice”, which disappears somewhere underground and never reaches the sea.
Authors:Ayman Hammoudeh, Riyadh Saymeh and Sabri Mahmoud
The kinetics of the liquid-phase hydrogenation of cinnamyl alcohol over Ir/Al2O3 catalyst (d ≈ 7 nm) was investigated in toluene under mild conditions (T = 25–95 °C, hydrogen pressure = 3–8 bar and cinnamyl
alcohol concentration = 0.0075–0.375 M). The kinetic results could be successfully modeled based on the assumption that the
Langmuir–Hinshelwood surface reaction between competitively adsorbed cinnamyl alcohol and hydrogen is the rate determining
step. The model predicts that cinnamyl alcohol requires two metallic sites to adsorb on with an adsorption constant of 1.4 M−1. The apparent activation energy of the reaction was experimentally determined to be ~26 kJ mol−1.
Authors:Andrzej Stańczak, Krystyna Rzeszowska-Modzelewska and Wiesława Lewgowd
The lipophilicity of new bioactive pyrimido[5,4-
)-ones and 1,2,3,4-tetrahydropyrimido[5,4-
]quinolin-2,4-diones has been determined by reversed-phase thin-layer chromatography with DMF-TRIS buffer as mobile phase. The
values of the compounds were linearly dependent on the concentration of DMF in the mobile phase. Experimental lipophilicity (log
) was determined by use of a calibration curve prepared by chromatography of six standards. The partition coefficients (log
) were calculated by use of software and compared with experimental values of log
) and log
, for the non-ionized molecules. The dissociation constant (p
) was calculated for all the compounds by use of the pKalc 3.1 prediction module of the Pallas system and used to define the partition coefficient (log
) of the compounds which can ionize under the experimental conditions. To evaluate the validity of the p
values obtained, experimental p
values were determined for the quinoline nitrogen atom of the compounds by UV-visible spectroscopic measurements.
The yield and average cross section for the reactions11B(p, n)11C,12C(p, )13N,13C(p, n)13N,
C(d, n)13N,14N(p, )11C,16O(p, )13N,16O(d, n)17F,16O(t, n)18F, and18O(p, n)18F have been measured in different compounds. The charged particles were created in the samples themselves either through recoil by scattering of 14 MeV neutrons off hydrogen and deuterium, or by the (n, t) reaction on6Li using thermal neutrons. The yields of reactions12C(d, n);16O(p, );16O(t, n) and18O(p, n) have been measured using proton, deuteron and triton spectra generated by 14 MeV neutrons in the reactions D(n, p)2n;6Li(n, d);7Li(n, d) and10B(n, d);7Li(n, t) and10B(n, t), respectively.
The most important limitations of DSC use in kinetics or in experimental study of heat sources comes from errors in heat flux
measurements in isothermal conditions. The 3 precision indicators which are proposed in this work are: the time constantK of entrance into the isotherm, the heat flux noiseB and the heat flux driftD. The characterize respectively the dynamics of heating, the short wave oscillations and the long waves ones. Common values
for standard devices are:K=1.5–15 s,B=0.5–5 μW,D=7–70 nW/s. A noise reduction is possible by regulation, but it leads to an increase of time constant.
Authors:Costas Giaginis, Demetris Dellis and Anna Tsantili-Kakoulidou
The reversed-phase TLC retention behavior of a series of structurally diverse drugs, mostly basic compounds, has been investigated with different aqueous mobile-phase components. Phosphate buffer, phosphate-buffered saline, and morpholinepropanesulfonic acid, with or without addition of
-decylamine, at pH 7.4, and phosphate buffer at pH 11.0 were used with different proportions of methanol as the mobile phase. The effect of the buffer constituents on extrapolated
values and the corresponding slopes,
, and their interrelationship, was evaluated. The different sets of
values were correlated with lipophilicity log
. MOPS was found to be more suitable than phosphate buffer for assessment of lipophilicity. Use of log
instead of log
, combined with use of the ionization-correction term
, led to improved correlation and revealed a reduced net effect of ionization on retention.