C[icy][lcy] Oc[tscy][icy][lcy][lcy][yacy]topob c[Pi]ektpa[lcy]ьh[ьix [lcy][icy]h[icy]ň [icy] bpemeha [zhcy][icy]зh[icy] boзБy[zhcy][dcy]ehhьix coctoЯh[icy]й atomob pe[dcy]Кoзeme[lcy]ьhьix [ecy][lcy]emehtob c [dcy]octpa[icy]ba[YUcy]щeйcЯ 4f-oБo[lcy]oкКoй

Data on classification of spectra and energy levels of atoms of rare earth elements with unfilled 4f-shells have been collected, systematized and analyzed. A brief account is given of methods for determining transition probabilities and lifetimes of the excited states of atoms and ions. Oscillator strengths for spectral lines of Nd(I), Sm(I), Eu(I), Gd(I), Dy(I), Tm(I) and Yb(I) have been measured using Rojdestvensky's hook method. Lifetimes of some of the excited states of Eu(I), Yb(I) and Yb(II) have been determined by using simultaneously the methods of delayed coincidence, hooks, and total absorption. Our results have been compared with those of other investigators. Atoms with unfilled 4f-shells show some regularities.     

Знaчeниe AКTГ для пroцecca oбraзoвaния кomплeкcныч coeдинeний гeпarинa в кroви пrи иmmoбилизaциoннom cтrecceThe role of ACTH in the formation of heparin complexes in blood under immobilization stress conditions

Under stress condition due to 30 min immobilization the total non-enzymatic fibrinolytic activity in rats is increased 4-fold, its proportion in the overall fibrinolytic activity of blood plasma being increased 1,5-fold. After pretreatment with ACTH (5–15 units) the same stress leads to more significant increase of non-enzymatic fibrinolysis which is 2,5 times higher than that in the absence of ACTH. The activity of fibrinogenheparin, epinephrineheparin, plasminogenheparin and plasminheparin complexes is increased 1,5–2,5 fold. ACTH induced a more efficient formation of heparin complexes also in the absence of stress. Its action is revealed in the course of 24 hours. Under blocked ACTH secretion as a result of DOCA treatment immobilization stress does not followed by increase of complex formation. The effect of ACTH on the formation of heparin complexes is mediated by stimulation of the adrenal cortex and by an increase in the corticosteroid level in the organism. Evidence of this has been produced from experiments on rats using ACTH treatment at different intervals after adrenalectomy. During first 24 hours after adrenalectomy when the additional cortical tissue is yet not active the injection of ACTH does not intensify heparin complexes formation. In 96 hours after adrebalectomy additional cortical tissue already responds to ACTH and accordingly stress after pretreatment with ACTH results in a greater increase of non=enzymatic fibrinolytic activity than that without ACTH.     

Strategies for Selling Paid Content on Newspaper and Magazine Web Sites: An Empirical Analysis of Bundling and Splitting of News and Magazine Articles

More and more newspaper and magazine Web sites offer paid content. However, selling information goods at a price higher than the marginal cost means finding a strategy for product or price differentiation. A possible strategy to solve this problem is the bundling of information goods. In this article, we analyze empirically, with quantitative statistic methods, strategies for selling bundled and unbundled content on newspaper and magazine Web sites. This analysis is based on the theoretical approach of Bakos and Brynjolfsson (1996). The article shows that a cannibalization takes place if the same bundle of information goods is offered in offline (printed) and online (digital) media at the same time. Traditional bundling models work nonetheless in an online media if the online content is rebundled (e.g., as dossiers about a topic), but thereby do not compete with the printed version.     

TightRope?

Surgical treatment of horizontally or vertically unstable acromioclavicular (AC) joint dislocations covers a wide range of surgical techniques, e.g. stabilization via a tension band, hooked tie plate or Bosworth screw. Many of these techniques are often accompanied by various complications so that a stabilizing, low complication and approximately physiological surgical treatment has moved increasingly into the focus of scientific interest. Through further development of the dynamic TightRope? system in syndesmosis surgery there is now the possibility to treat unstable AC joint dislocations in a similar manner. Advantages include improved cosmetic aspects through a less stressful surgical access as well as the reduction of postoperative infections and the fact that a second intervention to remove the metal implants is no longer necessary. Within the framework of biomechanical studies scientists were able to show that the TightRope? treatment was able to create a stable situation and to provide a sufficient load capacity.     

Кoличecтвeннoe oпpeдeлeниe cпeцифичecкич ингибитopoв пoлимepизaции фибpинa. Eдиницы тopмoзящeй aктивнocти

Fibrinogen and its degradation products are to be regarded as specific inhibitors of fibrin polymerization because of the protein-protein recognizing manner of their action. Some effects of specific inhibitors, e.g. prolongation of clotting time are easily measurable, yet, a proper quantitative presentation of the inhibitory activity is a separate problem requiring consideration. No series of direct measurements of inhibitory effects can adequately reflect the relative activities of inhibitors in question as the inhibitor concentration - effect dependence is non-linear. In Figure 1 curves for fibrinogen and fragment D are shown. Ordinate - relative prolongation of pure fibrin monomer clotting, abscissa - inhibitor concentration. The curves suggest some cooperativity in fibrin-inhibitor interactions. Dotted lines indicate a striking change in relative activity of the two inhibitors due to altering the concentration chosen for the activity-comparison test. Thus, the mere values of the inhibitory effects can give hardly more than semi-quantitative hints on the intrinsic inhibitory activities. To gain true values we made resort to the estimated weight quantities of inhibitors producing the same effect. As these quantities are obviously inversely proportional to the specific activity values of the respective inhibitors they immediately provide the information wanted. An arbitrary standard was chosen: 10-fold retardation of fibrin monomer clotting at definite medium conditions. So it became possible to express activities of specific inhibitors in terms of special units. In mixtures of inhibitors the overall activity (the total amount of activity units) was found equal or near to the sum of unit contents of all the components present. Consequently, the behaviour of components is virtually additive (Tables 2 and 3). This additivity means that the effects of individual components enhance each other in the same co-operative manner as the effectiveness of a single inhibitor is raised by its concentration increase (Figure 1). The arithmetical sum of separately exerted effects of components generally proved far below the actual effect of the corresponding mixture. This difference, as expected theoretically, was maximal if the components were represented in equivalent amounts, and it was less for a two-component system than for a three-component one. These results warrant the adequacy of the new method. Following determinations were carried out with this method. In fibrinogen solutions subjected to tryptic hydrolysis the activity unit content increased by about 300 per cent under optimal conditions, i.e. in the presence of Ca²⁺ and at 1:2250 trypsin-fibrinogen weight ratio. Specific activities of fibrinogen and purified fragment D were found to amount to 1.4 and 10.9 units per mg respectively. Throughout our work on fragment D isolation from tryptic fibrinogen digests activity yields were determined to check the procedure under trial.     

Axial compression behavior and analytical method of L-shaped column composed of concrete-filled square steel tubes

Based on the characteristics of an L-shaped column composed of concrete-filled square steel tubes, the axial compression experiment and nonlinear finite element analysis were carried out to study the mechanical property of the L-shaped column. The load-displacement curve for the L-shaped column, the deflection and load-strain curves for the mono columns were obtained by the axial compression experiment. The results show that the L-shaped column exhibits a flexural-torsional buckling failure mode. The numerical simulation by the finite element analysis shows that the bearing capacity and failure mode are in accordance with those of the axial compression experiment and the feasi- bility of the finite element analysis is proved. For the calculation of the bearing capacity of the L-shaped column com- posed of concrete-filled square steel tubes, an analytical method is proposed based on the theory of the elastic stability and spatial truss model. The results of the analytical method are in good agreement with those of the axial compression experiment and the finite element analysis.