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Annexins are proteins that bind lipids in the presence of calcium. Though multiple functions have been proposed for annexins, there is no general agreement on what annexins do or how they do it. We have used the well-studied conductance probes nonactin, alamethicin, and tetraphenylborate to investigate how annexins alter the functional properties of planar lipid bilayers. We found that annexin XII reduces the nonactin-induced conductance to approximately 30% of its original value. Both negative lipid and approximately 30 microM Ca(2+) are required for the conductance reduction. The mutant annexin XIIs, E105K and E105K/K68A, do not reduce the nonactin conductance even though both bind to the membrane just as wild-type does. Thus, subtle changes in the interaction of annexins with the membrane seem to be important. Annexin V also reduces nonactin conductance in nearly the same manner as annexin XII. Pronase in the absence of annexin had no effect on the nonactin conductance. But when added to the side of the bilayer opposite that to which annexin was added, pronase increased the nonactin-induced conductance toward its pre-annexin value. Annexins also dramatically alter the conductance induced by a radically different probe, alamethicin. When added to the same side of the bilayer as alamethicin, annexin has virtually no effect, but when added trans to the alamethicin, annexin dramatically reduces the asymmetry of the I-V curve and greatly slows the kinetics of one branch of the curve without altering those of the other. Annexin also reduces the rate at which the hydrophobic anion, tetraphenylborate, crosses the bilayer. These results suggest that annexin greatly reduces the ability of small molecules to cross the membrane without altering the surface potential and that at least some fraction of the active annexin is accessible to pronase digestion from the opposite side of the membrane.

The authors continue to report about results they have obtained in the process of creating a special introductory one-semester Laboratory Physics course «Search for Physics laws». It is known that the teaching experience and the results of the performed tests show that most students do not acquire the basic skills for conducting an experimental research. This course was built on the basis of the algorithm of systematic construction of students’ skills for carrying out an experimental research. The authors have used Galperin’s stepwise teaching procedure which was developed on the assumption that learning any kind of knowledge involves different kinds of actions. The authors have analysed different ways of how to expound the basic ideas of data analysis, and shown their connection with the point, syncretic and training-interval paradigms. Action diagrams are provided for each type of expounding. As an example of using the training-interval paradigm for teaching first-year students of a technical university, a specially designed lab session is presented in the article. The topic of the session is “The concept of a confidence interval”. Laboratory Work 1 “The Buffon-de Morgan Experiment”. This lab session meets several important requirements: a) the number of computations is minimised; b) a directly measurable quantity is considered; c) students are provided with a “fulcrum” in the form of a priori known true value of a quantity. A general view on measuring physics quantities is summarised in four quite unexpected for students “unpleasant axioms”: 1) none of measured values coincides with the true value of a quantity; 2) the mean of measured values does not coincide with the true value of a quantity; 3) even if, by a lucky chance, one of measured values or the mean coincided with the true value of a quantity, we would never know about it; 4) a confidence interval catches the true value of a measured quantity only in 68% of cases. The authors claim that the presented lab lesson allows demonstrating the equity of these “axioms” clearly and vividly, and that the organised laboratory sessions in the new way are significantly more successful in improving students’ basic skills of error analysis than traditional laboratory sessions.

The article considers the peculiarities of load formation in the continuous welded railroad tracks depending on temperature factors, geometric parameters and local curvature. The approach is proposed to determine the risk of distortion of the railway track depending on a combination of force and geometric factors on the ability of the ballast to keep the rail sleepers from moving laterally in relation to the direction of the track.

The article considers the problem of development of power loss minimization system in asynchronous motors with asymmetric voltage supply. The subject of the research is a continuous run of asynchronous motor based on artificial adjusting of characteristics in the area of nominal slipping with better energy indicators than at a operational segment of natural mechanical characteristics. The artificial control characteristic of a drive corresponding to power loss minimization mode is calculated in advance using the solution of extreme control concern. The paper demonstrates that under conditions of electric drive supplied by an asymmetric voltage source the one should apply a phase-by-phase control. The feedback action logic is as follows: reduction of the output voltage of thyristor converter and motor currents as a reducing of the load on the asynchronous motor shaft occurs. As a result, there appears the possibility to maintain the load angle equality of all the phases of asynchronous motor to an optimal value. This allows to solve the problem of power loss minimization in an asynchronous motor due to the load angle equality to the optimal value, and the problem of symmetrization due to the load angle equality in motor phases. The most significant result of the research is the developed automated scheme of symmetrization which is not only efficient with power source voltage asymmetry, but also with asymmetry of asynchronous motor parameters themselves. The proposed functional scheme of microprocessor control and the algorithm of control increase the possibilities of automated loss minimization system.

Dependence of the fracture-resistance of a PowerTrench MOSFET device on its topography in Cu bonding process was investigated. Two different topographies, namely dimple and round, have been tested. A significantly higher cratering rate has been clearly observed on dimple topography. The dimple topography exhibited a cratering rate of 371 k ppm levels compared to 0 ppm in round topographies. Three-dimensional nonlinear finite-element analysis has shown that the largest compressive and shear stresses and their locations were identified, respectively, in borophosphosilicate glass (BPSG)/barrier metal layers of the dimple topography. The round topography had the smallest stress in BPSG/barrier metal layers. The higher compressive stress transferred to silicon in the dimple topography during the bonding process can induce a local crack, consequently causing silicon fracturing during the shearing processes. A significant improvement in the cratering performance was observed when the Al bond pad metal layer was reinforced by adding a barrier layer sandwiched in the Al metal layers. The cratering rate decreased to 1300 ppm levels. Additionally, the change in composition of a BPSG layer caused cratering was briefly discussed and an oxygen rich BPSG film in round topography was confirmed by the energy dispersive spectroscopy (EDS) of a cross-sectional TEM sample. It has been found that the cratering rate on dimple topography significantly increased from 1 k ppm to 100 k ppm levels, when the resulting residual Al pad thickness is less than 0.65 μm for Cu bonding performed with different ultrasonic (US) power and bond forces. [ABSTRACT FROM AUTHOR]

Based on the experience of managing coastal marine, and limans ecosystems of Ukraine, the theoretical scheme of Integrative Ecological Management is considered. The scheme includes the “Basic Diagnostic” block for which the key tools are: Basin Assessment, Ecosystem Approach and Ecosystem Services. Geo-information Technologies are demonstrated in order to assess the catchment areas of some limans and coastal marine ecosystems of Ukraine. With the ecosystem approach, it is necessary to use functional indicators for assessing autotrophic, heterotrophic and decomposer communities of the ecosystem, the bind of which is associated with Ecological Status of the water body. It is indicated that an important goal of environmental management is reducing the intensity of anthropogenic flows of substance and energy, which cause destruction of the ecological balance and devaluation of ecosystem services. For the second block of the scheme - “Decision Making” it is proposed to use Priority Management Algorithm principle as an effective tool which allows to achieve the target maximum at minimal cost. At the final stage of the “Target Result”, recommendations that are offered to stakeholders at the local, regional and national level must achievement the main objectives of the Integrative Ecological Management of coastal marine ecosystems and limans.

Material fatigue damage accumulation is recognized as one of the least inspectable and controllable operational damage mechanisms of crane structures. The scope method measures electro-magnetic properties of steels being in service, to assess their relative changes induced by the fatigue damage accompanying microstructural effects. The authors’ theoretical and experimental research suggested that the most relevant magnetic parameter to measure is the coercive force Hc, which is a characteristic of ferritic steels’ magnetization-demagnetization hysteresis loop. The authors proposed and developed a correction factor to normalize changes in Hc for various carbon steel thicknesses in the practical range from 5mm to 20mm, and drawn the coercive force nomograms which quantify the extent of damage for typical structural steels used in cranes. This research provided a scientifically justified basis for structures remnant resource assessments. Application of the Coercimetric method contributes into the risk control and promotes industrial safety in lifting equipment operations. The method itself can be practically useful for resolving integrity management challenges in a wide range of industries.