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11.
Marko Hölbl Tatjana Welzer Boštjan Brumen 《Journal of Computer and System Sciences》2012,78(1):142-150
Two-party authenticated key agreement protocols using pairings have gained much attention in the cryptographic community. Several protocols of this type where proposed in the past of which many were found to be flawed. This resulted in attacks or the inability to conform to security attributes. In this paper, we propose an efficient identity-based authenticated key agreement protocol employing pairings which employs a variant of a signature scheme and conforms to security attributes. Additionally, existing competitive and the proposed protocol are compared regarding efficiency and security. The criteria for efficiency are defined in this paper, whereas the criteria for security are defined by the fulfilment of security attributes from literature. 相似文献
12.
Henny M. Borsboom Tatjana Claasen-Vujčić Harry J. G. Gaykema Toon Mehlkopf 《Magma (New York, N.Y.)》1997,5(1):33-37
The birdcage resonator is frequently used in conventional MRI because of its excellent attributes. Its use in low-field MRI
is restricted to field strengths higher than, for example, 0.1 T, dependent on the size of the coil. This is because of the
intrinsically low inductance value of the birdcage coils. Furthermore, the sensitivity of the birdcage at low field strengths
is significantly lower when compared to, for example, the solenoid. Both problems can be overcome with the multiturn technique
and a novel wound birdcage coil. The quadrature mode wound birdcage coil presented in this paper can be used at frequencies
as low as 100 kHz. Its sensitivity is also increased when compared to the conventional strip-ring birdcage. Homogeneity effective
volume, and methods to increase the resonator bandwidth to match the signal bandwidth are left intact. The latter is a typical
low-field problem. 相似文献
13.
Stefan Alexander Tennigkeit Raziye Karapinar Till Rudack Max-Aylmer Dreier Philipp Althoff Dennis Eickelbeck Tatjana Surdin Michelle Grömmke Melanie D. Mark Katharina Spoida Mathias Lübben Udo Höweler Prof. Dr. Stefan Herlitze Prof. Dr. Klaus Gerwert 《Chembiochem : a European journal of chemical biology》2019,20(14):1766-1771
The primary goal of optogenetics is the light-controlled noninvasive and specific manipulation of various cellular processes. Herein, we present a hybrid strategy for targeted protein engineering combining computational techniques with electrophysiological and UV/visible spectroscopic experiments. We validated our concept for channelrhodopsin-2 and applied it to modify the less-well-studied vertebrate opsin melanopsin. Melanopsin is a promising optogenetic tool that functions as a selective molecular light switch for G protein-coupled receptor pathways. Thus, we constructed a model of the melanopsin Gq protein complex and predicted an absorption maximum shift of the Y211F variant. This variant displays a narrow blue-shifted action spectrum and twofold faster deactivation kinetics compared to wild-type melanopsin on G protein-coupled inward rectifying K+ (GIRK) channels in HEK293 cells. Furthermore, we verified the in vivo activity and optogenetic potential for the variant in mice. Thus, we propose that our developed concept will be generally applicable to designing optogenetic tools. 相似文献
14.
Tatjana N. Basharina Elena N. Danilovtseva Stanislav N. Zelinskiy Igor V. Klimenkov Yelena V. Likhoshway Vadim V. Annenkov 《SILICON》2012,4(4):239-249
The effect of three Group IV metals (titanium, zirconium and tin) on the growth, morphology and chemical composition of the freshwater diatom Synedra acus subsp. radians (Kützing) Skabichevsky was studied and compared with germanium. The elements in their highest oxidation states were introduced into the culture medium in the form of hydroxides. Germanium was found to be toxic at ??5?mol. % of the total Ge-Si content in the culture medium. In the presence of other elements, a slight decrease in the cell division rate was observed independent of the element within 1?C15% content interval. The analysis of the obtained biomass and silica valves revealed the presence of all the added elements within the cells. However, only germanium was incorporated into the valves in considerable amounts. S. acus cultivation with the addition of 5% Group IV elements resulted in cells having the following aberrations in the structure of the silica valves: changes in valve shape, thickening of valves, alterations of the areolae rows, irregularity or absence of the areolae and a decrease in the mechanical strength of valves. Moreover, the effect of Group IV elements on silica formation was simulated in vitro using a synthetic polymer bearing polyamine and phosphate groups found in silaffines (proteins from diatom frustules). The studied elements were observed to provoke the formation of unstable silica particles in solution. We propose that the observed effects of germanium, titanium, zirconium and tin on diatom growth and structure are due to uncontrollable silica condensation. 相似文献
15.
Bipedal animals experience ground reaction forces (GRFs) that pass close to the centre of mass (CoM) throughout stance, first decelerating the body, then re-accelerating it during the second half of stance. This results in fluctuations in kinetic energy, requiring mechanical work from the muscles. However, here we show analytically that, in extreme cases (with a very large body pitch moment of inertia), continuous alignment of the GRF through the CoM requires greater mechanical work than a maintained vertical force; we show numerically that GRFs passing between CoM and vertical throughout stance are energetically favourable under realistic conditions; and demonstrate that the magnitude, if not the precise form, of actual CoM-torque profiles in running is broadly consistent with simple mechanical work minimization for humans with appropriate pitch moment of inertia. While the potential energetic savings of CoM-torque support strategies are small (a few per cent) over the range of human running, their importance increases dramatically at high speeds and stance angles. Fast, compliant runners or hoppers would benefit considerably from GRFs more vertical than the zero-CoM-torque strategy, especially with bodies of high pitch moment of inertia—suggesting a novel advantage to kangaroos of their peculiar long-head/long-tail structure. 相似文献
16.
Joseph Berry Tonio Buonassisi David A. Egger Gary Hodes Leeor Kronik Yueh‐Lin Loo Igor Lubomirsky Seth R. Marder Yitzhak Mastai Joel S. Miller David B. Mitzi Yaron Paz Andrew M. Rappe Ilan Riess Boris Rybtchinski Oscar Stafsudd Vladan Stevanovic Michael F. Toney David Zitoun Antoine Kahn David Ginley David Cahen 《Advanced materials (Deerfield Beach, Fla.)》2015,27(35):5102-5112
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20.
Thermal and elastic properties of poly(vinyl chloride) (PVC) + chlorinated polyethylene (CPE) blends
Robert?D.?MaksimovEmail author Tatjana?Ivanova Janis?Zicans Sophia?N.?Negreeva Egils?Plume 《Materials Research Innovations》2003,7(5):326-330
Eight types of PVC + CPE blends with different weight ratios (PVC/CPE = 100/0, 90/10, 80/20, 60/40, 40/60, 20/80, 10/90, and 0/100) are tested. Data on the heat conductivity, thermal diffusivity, and heat capacity of the blends investigated are reported. Primary attention is paid to the structural approach for effective elastic constants: bulk, shear, and Young's modulae. The blends are considered as random mixtures of two isotropic constituents. It is found that the elastic moduli may be well represented by the Kerner and Budiansky equations. 相似文献