ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    facet.materialart.
    Unknown
    Compressional ULF wave modulation of energetic particles in the inner magnetosphere (2016)
    Wiley
    Details
    Publication Date: 2016-05-31
    Description: We present Van Allen Probes observations of modulations in the flux of very energetic electrons up to a few MeV and protons between 1200 − 1400 UT on February 19th, 2014. During this event the spacecraft were in the dayside magnetosphere at L ⋆ ≈5.5. The modulations extended across a wide range of particle energies, from 79.80 keV to 2.85 MeV for electrons and from 82.85 keV to 636.18 keV for protons. The fluxes of π /2 pitch angle particles were observed to attain maximum values simultaneously with the ULF compressional magnetic field component reaching a minimum. We use peak-to-valley ratios to quantify the strength of the modulation effect, finding that the modulation is larger at higher energies than at lower energies. It is shown that the compressional wave modulation of the particle distribution is due to the mirror effect, which can trap relativistic electrons efficiently for energies up to 2.85 MeV , and trap protons up to ≈600 keV . Larger peak-to-valley ratios at higher energies also attributed to the mirror effect. Finally, we suggest that protons with energies higher than 636.18 keV can not be trapped by the compressional ULF wave efficiently due to the finite Larmor radius effect.
    Print ISSN: 0148-0227
    Topics: Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 2
    facet.materialart.
    Unknown
    Calcium signaling by HBx protein in hepatitis B virus DNA replication (2001)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 2001-12-18
    Description: Hepatitis B virus (HBV) infects more than 300 million people and is a leading cause of liver cancer and disease. The HBV HBx protein is essential for infection; HBx activation of Src is important for HBV DNA replication. In our study, HBx activated cytosolic calcium-dependent proline-rich tyrosine kinase-2 (Pyk2), a Src kinase activator. HBx activation of HBV DNA replication was blocked by inhibiting Pyk2 or calcium signaling mediated by mitochondrial calcium channels, which suggests that HBx targets mitochondrial calcium regulation. Reagents that increased cytosolic calcium substituted for HBx protein in HBV DNA replication. Thus, alteration of cytosolic calcium was a fundamental requirement for HBV replication and was mediated by HBx protein.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Bouchard, M J -- Wang, L H -- Schneider, R J -- F32CA-4476/CA/NCI NIH HHS/ -- R0ICA-565633/CA/NCI NIH HHS/ -- New York, N.Y. -- Science. 2001 Dec 14;294(5550):2376-8.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/11743208" target="_blank"〉PubMed〈/a〉
    Keywords: Calcium/metabolism ; Calcium Channels/metabolism ; *Calcium Signaling ; Cyclosporine/pharmacology ; Cytosol/metabolism ; *DNA Replication ; DNA, Viral/biosynthesis ; Egtazic Acid/*analogs & derivatives/pharmacology ; Enzyme Activation ; Focal Adhesion Kinase 2 ; Genome, Viral ; Hepatitis B virus/genetics/*physiology ; Humans ; Mitochondria/metabolism ; Phosphorylation ; Plasmids ; Protein-Tyrosine Kinases/metabolism ; Signal Transduction ; Trans-Activators/genetics/*metabolism ; Transcription, Genetic ; Transfection ; Tumor Cells, Cultured ; Virus Replication ; src-Family Kinases/metabolism
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 3
    facet.materialart.
    Unknown
    Structural insights into the evolution of an antibody combining site (1997)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1997-06-13
    Description: The crystal structures of a germline antibody Fab fragment and its complex with hapten have been solved at 2.1 A resolution. These structures are compared with the corresponding crystal structures of the affinity-matured antibody, 48G7, which has a 30,000 times higher affinity for hapten as a result of nine replacement somatic mutations. Significant changes in the configuration of the combining site occur upon binding of hapten to the germline antibody, whereas hapten binds to the mature antibody by a lock-and-key fit mechanism. The reorganization of the combining site that was nucleated by hapten binding is further optimized by somatic mutations that occur up to 15 from bound hapten. These results suggest that the binding potential of the primary antibody repertoire may be significantly expanded by the ability of germline antibodies to adopt more than one combining-site configuration, with both antigen binding and somatic mutation stabilizing the configuration with optimal hapten complementarity.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Wedemayer, G J -- Patten, P A -- Wang, L H -- Schultz, P G -- Stevens, R C -- R01 AI39089/AI/NIAID NIH HHS/ -- New York, N.Y. -- Science. 1997 Jun 13;276(5319):1665-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, University of California, Berkeley, CA 94720, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/9180069" target="_blank"〉PubMed〈/a〉
    Keywords: Antibodies, Catalytic/*chemistry/genetics/immunology ; Antibody Affinity ; Antibody Diversity ; Antigen-Antibody Complex ; Antigen-Antibody Reactions ; Binding Sites ; *Binding Sites, Antibody ; Crystallography, X-Ray ; *Evolution, Molecular ; Haptens/immunology ; Hydrogen Bonding ; Immunoglobulin Fab Fragments/*chemistry/genetics/immunology ; Molecular Sequence Data ; Mutation ; Protein Conformation ; Protein Structure, Secondary
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 4
    facet.materialart.
    Unknown
    Domain topology and domain switching kinetics in a hybrid improper ferroelectric (2016)
    Springer Nature
    Details
    Publication Date: 2016-05-26
    Description: Article Charged ferroelectric domain walls show promise for two-dimensional conduction, but their abundance within (Ca,Sr) 3 Ti 2 O 7 crystals is poorly understood. Here, Huang et al . discover topology related domain structures in such materials, which reveal the rich nature of hybrid improper ferroelectricity. Nature Communications doi: 10.1038/ncomms11602 Authors: F. -T. Huang, F. Xue, B. Gao, L. H. Wang, X. Luo, W. Cai, X. -Z. Lu, J. M. Rondinelli, L. Q. Chen, S. -W. Cheong
    Electronic ISSN: 2041-1723
    Topics: Biology , Chemistry and Pharmacology , Natural Sciences in General , Physics
    Published by Springer Nature
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 5
    facet.materialart.
    Unknown
    Generating mechanism for higher-order rogue waves (2013)
    American Physical Society (APS)
    Details
    Publication Date: 2013-05-25
    Description: Author(s): J. S. He, H. R. Zhang, L. H. Wang, K. Porsezian, and A. S. Fokas We introduce a mechanism for generating higher-order rogue waves (HRWs) of the nonlinear Schrödinger (NLS) equation: the progressive fusion and fission of n degenerate breathers associated with a critical eigenvalue λ 0 creates an order- n HRW. By adjusting the relative phase of the breathers in the i... [Phys. Rev. E 87, 052914] Published Fri May 24, 2013
    Keywords: Nonlinear Dynamics and Chaos
    Print ISSN: 1539-3755
    Electronic ISSN: 1550-2376
    Topics: Physics
    Published by American Physical Society (APS)
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 6
    facet.materialart.
    Unknown
    Breather and rogue wave solutions of a generalized nonlinear Schrödinger equation (2013)
    American Physical Society (APS)
    Details
    Publication Date: 2013-05-31
    Description: Author(s): L. H. Wang, K. Porsezian, and J. S. He In this paper, using the Darboux transformation, we demonstrate the generation of first-order breather and higher-order rogue waves from a generalized nonlinear Schrödinger equation with several higher-order nonlinear effects representing femtosecond pulse propagation through nonlinear silica fiber.... [Phys. Rev. E 87, 053202] Published Thu May 30, 2013
    Keywords: Classical Physics
    Print ISSN: 1539-3755
    Electronic ISSN: 1550-2376
    Topics: Physics
    Published by American Physical Society (APS)
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 7
    facet.materialart.
    Unknown
    MMS observations of electron scale magnetic peak (2017)
    Wiley
    Details
    Publication Date: 2017-12-30
    Description: The sudden enhancements of magnetic strength, named magnetic peaks (MPs), are often observed in the magnetosheath of magnetized planets. They are usually identified as flux ropes (FRs) or magnetic mirror mode structures. Previous studies of MPs are mostly on the magnetohydrodynamics (MHD) scale. In this study, an electron scale MP is reported in the Earth magnetosheath. We present a typical case with a scale of ~7 electron gyroradii and a duration of ~0.18 s. A strong magnetic disturbance and associated electrical current are detected. Electron vortex is found perpendicular to the magnetic field line and is self-consist with the peak. We use multi-point spacecraft techniques to determine the propagation velocity of the MP structure, and find that the magnetic peak does propagate relative to the plasma (ion) flow. This is very different from the magnetic mirror mode that does not propagate relative to the plasma flow. Furthermore, we developed an efficient method that can effectively distinguish “magnetic bottle like” and “FRs like” structures. The MP presented in this study is identified as “magnetic bottle like” type. The mechanism to generate the electron scale “magnetic bottle like” structure is still unclear, suggesting that new theory needs to be developed to understand such small scale phenomena.
    Print ISSN: 0094-8276
    Electronic ISSN: 1944-8007
    Topics: Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 8
    facet.materialart.
    Unknown
    Single-crystal x-ray diffraction structures of covalent organic frameworks (2018)
    American Association for the Advancement of Science (AAAS)
    In: Science
    Details
    Publication Date: 2018-07-06
    Description: The crystallization problem is an outstanding challenge in the chemistry of porous covalent organic frameworks (COFs). Their structural characterization has been limited to modeling and solutions based on powder x-ray or electron diffraction data. Single crystals of COFs amenable to x-ray diffraction characterization have not been reported. Here, we developed a general procedure to grow large single crystals of three-dimensional imine-based COFs (COF-300, hydrated form of COF-300, COF-303, LZU-79, and LZU-111). The high quality of the crystals allowed collection of single-crystal x-ray diffraction data of up to 0.83-angstrom resolution, leading to unambiguous solution and precise anisotropic refinement. Characteristics such as degree of interpenetration, arrangement of water guests, the reversed imine connectivity, linker disorder, and uncommon topology were deciphered with atomic precision—aspects impossible to determine without single crystals.
    Keywords: Chemistry, Materials Science
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 9
    facet.materialart.
    Unknown
    Ion-scale spectral break in the normal plasma beta range in the solar wind turbulence (2018)
    Wiley
    Details
    Publication Date: 2018-01-04
    Description: The spectral break ( f b ) of magnetic fluctuations at the ion scale in the solar wind is considered to give important clue on the turbulence dissipation mechanism. Among several possible mechanisms, the most notable two are related respectively to proton thermal gyro-radius ρ i and proton inertial length d i . The corresponding frequencies of them are f ρ i = V S W /(2 π ρ i ) and f d i = V S W /(2 π d i ), respectively, where V S W is the solar wind speed. However, no definite conclusion has been given for which one is more reasonable because the two parameters have similar value when plasma beta β ∼ 1. Here, we do a statistical study to see if the two ratios f b / f ρ i and f b / f d i have different dependence on β in the solar wind turbulence with 0.1 〈 β 〈 1.3. From magnetic measurements by the WIND spacecraft, we select 141 data sets with each one longer than 13 hours. We find that the ratio f b / f d i is statistically not dependent on β , and the average value of it is 0.48 ± 0.06. However, f b / f ρ i increases with increasing β clearly, and is significantly smaller than f b / f d i when β 〈 0.8. These new results show that f b is statistically 0.48 f d i , and the influence of β could be negligible in the studied β range. It indicates a preference of the dissipation mechanism associated with d i in the solar wind with 0.1 〈 β 〈 0.8. Further theoretical studies are needed to give detailed explanation.
    Print ISSN: 0148-0227
    Topics: Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 10
    facet.materialart.
    Unknown
    Possible noise nature of Elsässer variable z− in highly Alfvénic solar wind fluctuations (2018)
    Wiley
    Details
    Publication Date: 2018-01-06
    Description: It has been a long-standing debate on the nature of Elsässer variable z − observed in the solar wind fluctuations. It is widely believed that z − represents inward-propagating Alfvén waves and interacts non-linearly with z + (outward-propagating Alfvén waves) to generate energy cascade. However, z − variations sometimes show a feature of convective structures. Here we present a new data analysis on auto-correlation functions of z − in order to get some definite information on its nature. We find that there is usually a large drop on the z − auto-correlation function when the solar wind fluctuations are highly Alfvénic. The large drop observed by Helios 2 spacecraft near 0.3 AU appears at the first non-zero time lag τ = 81 s, where the value of the auto-correlation coefficient drops to 25% − 65% of that at τ = 0 s. Beyond the first non-zero time lag, the auto-correlation coefficient decreases gradually to zero. The drop of z − correlation function also appears in the WIND observations near 1 AU. These features of the z − correlation function may suggest that z − fluctuations consist of two components: high-frequency white noise and low-frequency pseudo structures, which correspond to flat and steep parts of z − power spectrum, respectively. This explanation is confirmed by doing a simple test on an artificial time series, which is obtained from the superposition of a random data series on its smoothed sequence. Our results suggest that in highly Alfvénic fluctuations, z − may not contribute importantly to the interactions with z + to produce energy cascade.
    Print ISSN: 0148-0227
    Topics: Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...