34 research outputs found
Features of Buildings Made of Soil Materials in Seismic Areas
The article discusses the technology of producing thermoelectric materials under inert gas pressure, which makes it possible to provide reproducible results from melting to melting and to synthesize sufficiently large amounts of a working substance
Optimum control strategies for maximum thrust production in underwater undulatory swimming
Fish, cetaceans and many other aquatic vertebrates undulate their bodies to
propel themselves through water. Numerous studies on natural, artificial or
analogous swimmers are dedicated to revealing the links between the kinematics
of body oscillation and the production of thrust for swimming. One of the most
open and difficult questions concerns the best kinematics to maximize this
later quantity for given constraints and how a system strategizes and adjusts
its internal parameters to reach this maximum. To address this challenge, we
exploit a biomimetic robotic swimmer to determine the control signal that
produces the highest thrust. Using machine learning techniques and intuitive
models, we find that this optimal control consists of a square wave function,
whose frequency is fixed by the interplay between the internal dynamics of the
swimmer and the fluid-structure interaction with the surrounding fluid. We then
propose a simple implementation for autonomous robotic swimmers that requires
no prior knowledge of systems or equations. This application to aquatic
locomotion is validated by 2D numerical simulations
Toward verification of the Riemann hypothesis: Application of the Li criterion
We substantially apply the Li criterion for the Riemann hypothesis to hold.
Based upon a series representation for the sequence \{\lambda_k\}, which are
certain logarithmic derivatives of the Riemann xi function evaluated at unity,
we determine new bounds for relevant Riemann zeta function sums and the
sequence itself. We find that the Riemann hypothesis holds if certain
conjectured properties of a sequence \eta_j are valid. The constants \eta_j
enter the Laurent expansion of the logarithmic derivative of the zeta function
about s=1 and appear to have remarkable characteristics. {\em On our
conjecture}, not only does the Riemann hypothesis follow, but an inequality
governing the values \lambda_n and inequalities for the sums of reciprocal
powers of the nontrivial zeros of the zeta function.Comment: to appear in Math. Physics, Analysis and Geometry; 1 figur
Report on the results of the household budget survey in 1999
Available from Latvian Academic Library / LAL - Latvian Academic LibrarySIGLELVLatvi
Effects of cobra venom cytotoxins CTII and CTI on isolated mitochondria and large unilamellar liposomes.
<p><sup>31</sup>P-NMR spectra of mitochondria or large unilamellar liposomes with different lipid compositions were monitored at 10°C. (<b>A</b>) <sup>31</sup>P-NMR spectrum of a mitochondrial sample. (<b>B)</b><sup>31</sup>P-NMR spectrum of mitochondria treated with 9 × 10<sup>−4</sup> M of CTII. (<b>C</b>) <sup>31</sup>P-NMR spectrum of mitochondria treated with 9 × 10<sup>−4</sup> M of CTI. Broken lines in A and B are saturation spectra observed after applying a DANTE train of saturation pulses at the high-field side of the lamellar spectrum (see arrow with letter <b>S</b>). <sup>31</sup>P-NMR spectra of large unilamellar liposomes of PC+ 10 mol% CL (<b>D</b>) and of PC+ 10 mol% PS (<b>E</b>) monitored at 18°C and treated with the indicated cytotoxin-lipid ratios of CTII and CTI. All <sup>31</sup>P-NMR data shown in this figure from isolated mitochondria and large unilamellar liposomes is representative of two independent experiments that showed similar results. Each sample was measured in triplicate readings. <b>F-H.</b><sup>31</sup>P-NMR spectra after applying a DANTE train of saturation pulses at the high-field peak of the lamellar spectrum of large unilamellar liposomes of PC+10 mol% CL treated with CTII (<b>F</b>) and CTI (<b>G</b>) and of PC+10 mol% PS treated with CTII (<b>H</b>) at the cytotoxin/lipid molar ratios of 0.01 (bottom spectra) and 0.02 (top spectra). Position of the signals in saturation spectra in <b>F</b>-<b>H</b> coincides with the position of <sup>31</sup>P-NMR signal B.</p
Visual summary of residues in cytotoxins that interact and do not interact with lipids.
<p>Ribbon diagrams of CTI and CTII depicting the charged amino residues (ball and stick representations) that are predicted to interact with phospholipid head groups CL (top two panels), with PS (middle panels) or with PC (bottom two panels) based on the top ranked docking conformations identified by AutoDock simulations. Interacting charged amino acid residues are marked in yellow symbols and numbers and represented in stick mode. Charged amino acid residues in CTI and CTII that do not interact with PC, PS or CL are depicted in sphere mode representations and marked in white symbols and numbers. For a complete list of interactive residues and type of bonds produced with chemical groups of lipids. (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0129248#pone.0129248.s003" target="_blank">S1</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0129248#pone.0129248.s002" target="_blank">S2</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0129248#pone.0129248.s005" target="_blank">S3</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0129248#pone.0129248.s006" target="_blank">S4</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0129248#pone.0129248.s007" target="_blank">S5</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0129248#pone.0129248.s008" target="_blank">S6</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0129248#pone.0129248.s009" target="_blank">S7</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0129248#pone.0129248.s010" target="_blank">S8</a>, and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0129248#pone.0129248.s011" target="_blank">S9</a> Tables).</p
Cell permeabilizing activities of CTI and CTII on lipid bilayers.
<p><sup>1</sup>H-NMR spectra derived from the N<sup>+</sup>(CH<sub>3</sub>)<sub>3</sub> groups of PC in large unilamellar liposomes composed of PC+ 10 mol% CL (<b>A</b> and <b>B</b>) or in PC+ 10 mol% PS (<b>C</b> and <b>D</b>) in the presence of potassium ferricyanide at 18°C and in the presence of CTII (<b>A</b> and <b>C,</b> top spectra) or of CTI (<b>B</b> and <b>D,</b> top spectra) at a cytotoxin/lipid molar ratio of 0.02. This figure shows a representative <sup>1</sup>H-NMR traces from three independent experiments that showed similar results. Each sample (<b>A-D</b>) was measured in triplicate.</p
CLUSTAL 2.1 multiple amino acid sequence alignment of cobra venom cytotoxins.
<p><b>A.</b> Amino acid sequence alignment of cobra venom cytotoxins, with resolved crystal structures, include 2CDX from <i>Naja naja atra</i>, 1ZAD (CTI/Vc1, underlined): <i>Naja naja oxiana</i>, 1CDT: <i>Naja mossambica mossambica</i>, 1CRE from <i>Naja naja atra</i>, 4OM5 from <i>Naja naja atra</i>, 2CRT from <i>Naja naja atra</i>, 1CB9 (CTII/Vc5, underlined) from <i>Naja naja oxiana</i>, 1UG4 from <i>Naja naja atra</i>, 2CCX from <i>Naja mossambica mossambica</i>, 1CVO from <i>Naja naja atra</i>. Conserved Cys residues are highlighted in yellow. Basic and acidic residues are highlighted in red and blue respectively. The amino acid residues located within each of the three loops (I-III) are highlighted in gray below the amino acid sequences. The variable residues Ser28 and Pro30 in loop 2, characteristic of S and P-type cytotoxins respectively, are highlighted in green. The hydrophobic residues of the three loops are bolded. The overall charge and isoelectric point (PI) value for each cytotoxin are shown in two columns to the right of the amino acid alignment. <b>B.</b> Ribbon diagrams of the crystal structures of CTI (PDB#1ZAD) and CTII (PDB#1CB9). All basic amino acid residues are represented as stick representations and labeled accordingly (Lys: lysine, Arg: arginine).</p