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  • 1
    Publication Date: 2018-01-05
    Description: The ionized upper layer of Saturn’s atmosphere, its ionosphere, provides a closure of currents mediated by the magnetic field to other electrically charged regions (for example, rings) and hosts ion-molecule chemistry. In 2017, the Cassini spacecraft passed inside the planet’s rings, allowing in situ measurements of the ionosphere. The Radio and Plasma Wave Science instrument detected a cold, dense, and dynamic ionosphere at Saturn that interacts with the rings. Plasma densities reached up to 1000 cubic centimeters, and electron temperatures were below 1160 kelvin near closest approach. The density varied between orbits by up to two orders of magnitude. Saturn’s A- and B-rings cast a shadow on the planet that reduced ionization in the upper atmosphere, causing a north-south asymmetry.
    Keywords: Geochemistry, Geophysics, Planetary Science
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 2
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] To measure the -/-radiation of Mars the Phobos spacecraft was provided with a 7-ray spectrometer with a 100x100 mm CsI(Tl) crystal. This -y-ray spectrometer was more efficient than those used earlier. The energy range was 0.3-10.0 MeV. The energy resolution of the detector (with respect to Cs137) ...
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 109 (1998), S. 9958-9966 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We present the results of experimental studies of light scattering in the isotropic phase of two mesogens, p-n-pentyl-p′-cyanobiphenyl (5CB) and p-n-pentyl-(p′-cyanophenyl)-cyclohexane (5PCH) and in their solutions in CCl4, a globular molecules solvent. Integral intensities of various Raman bands and Rayleigh wing polarized spectra were studied. Dilution experiments have shown that in mesogen systems, due to molecular interactions, intensity of light scattering may be substantially (about 30%) reduced. Isotropic component of the scattered light is influenced by orientation-translational molecular correlations, while for anisotropic component pure orientational molecular correlations are also important. As a result, depolarization ratio in the condensed state may be substantially different from that for the isolated molecule and may vary through the mesomorphic phase transitions. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 4
    Publication Date: 2011-02-15
    Description: The TrkH/TrkG/KtrB proteins mediate K(+) uptake in bacteria and probably evolved from simple K(+) channels by multiple gene duplications or fusions. Here we present the crystal structure of a TrkH from Vibrio parahaemolyticus. TrkH is a homodimer, and each protomer contains an ion permeation pathway. A selectivity filter, similar in architecture to those of K(+) channels but significantly shorter, is lined by backbone and side-chain oxygen atoms. Functional studies showed that TrkH is selective for permeation of K(+) and Rb(+) over smaller ions such as Na(+) or Li(+). Immediately intracellular to the selectivity filter are an intramembrane loop and an arginine residue, both highly conserved, which constrict the permeation pathway. Substituting the arginine with an alanine significantly increases the rate of K(+) flux. These results reveal the molecular basis of K(+) selectivity and suggest a novel gating mechanism for this large and important family of membrane transport proteins.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3077569/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3077569/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Cao, Yu -- Jin, Xiangshu -- Huang, Hua -- Derebe, Mehabaw Getahun -- Levin, Elena J -- Kabaleeswaran, Venkataraman -- Pan, Yaping -- Punta, Marco -- Love, James -- Weng, Jun -- Quick, Matthias -- Ye, Sheng -- Kloss, Brian -- Bruni, Renato -- Martinez-Hackert, Erik -- Hendrickson, Wayne A -- Rost, Burkhard -- Javitch, Jonathan A -- Rajashankar, Kanagalaghatta R -- Jiang, Youxing -- Zhou, Ming -- DK088057/DK/NIDDK NIH HHS/ -- GM05026/GM/NIGMS NIH HHS/ -- GM05026-SUB0007/GM/NIGMS NIH HHS/ -- HL086392/HL/NHLBI NIH HHS/ -- K05 DA022413/DA/NIDA NIH HHS/ -- P30 EB009998/EB/NIBIB NIH HHS/ -- R01 DK088057/DK/NIDDK NIH HHS/ -- R01 DK088057-01/DK/NIDDK NIH HHS/ -- R01 HL086392/HL/NHLBI NIH HHS/ -- R01 HL086392-05/HL/NHLBI NIH HHS/ -- Howard Hughes Medical Institute/ -- England -- Nature. 2011 Mar 17;471(7338):336-40. doi: 10.1038/nature09731. Epub 2011 Feb 13.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Physiology & Cellular Biophysics, College of Physicians and Surgeons, Columbia University, 630 West 168th Street, New York, New York 10032, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21317882" target="_blank"〉PubMed〈/a〉
    Keywords: ATP-Binding Cassette Transporters/chemistry ; Amino Acid Sequence ; Crystallography, X-Ray ; Escherichia coli Proteins/chemistry ; Ion Channel Gating ; Ion Transport ; Models, Molecular ; Molecular Sequence Data ; Potassium/metabolism ; Potassium Channels/*chemistry/*metabolism ; Structure-Activity Relationship ; Substrate Specificity ; Vibrio parahaemolyticus/*chemistry
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 5
    Publication Date: 2013-07-28
    Description: The essential bacterial protein FtsZ is a guanosine triphosphatase that self-assembles into a structure at the division site termed the "Z ring". During cytokinesis, the Z ring exerts a constrictive force on the membrane by using the chemical energy of guanosine triphosphate hydrolysis. However, the structural basis of this constriction remains unresolved. Here, we present the crystal structure of a guanosine diphosphate-bound Mycobacterium tuberculosis FtsZ protofilament, which exhibits a curved conformational state. The structure reveals a longitudinal interface that is important for function. The protofilament curvature highlights a hydrolysis-dependent conformational switch at the T3 loop that leads to longitudinal bending between subunits, which could generate sufficient force to drive cytokinesis.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3816583/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3816583/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Li, Ying -- Hsin, Jen -- Zhao, Lingyun -- Cheng, Yiwen -- Shang, Weina -- Huang, Kerwyn Casey -- Wang, Hong-Wei -- Ye, Sheng -- 1F32GM100677-01A1/GM/NIGMS NIH HHS/ -- DP2 OD006466/OD/NIH HHS/ -- DP2OD006466/OD/NIH HHS/ -- F32 GM100677/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 2013 Jul 26;341(6144):392-5. doi: 10.1126/science.1239248.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Life Sciences Institute, Zhejiang University, Hangzhou, 310058 Zhejiang, P.R. China.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/23888039" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Bacterial Proteins/*chemistry/genetics/*metabolism ; Cell Membrane/physiology ; Crystallography, X-Ray ; *Cytokinesis ; Cytoskeletal Proteins/*chemistry/genetics/*metabolism ; Escherichia coli/chemistry ; Guanosine Diphosphate/chemistry/metabolism ; Guanosine Triphosphate/metabolism ; Hydrolysis ; Hydrophobic and Hydrophilic Interactions ; Models, Molecular ; Molecular Dynamics Simulation ; Molecular Sequence Data ; Mycobacterium tuberculosis/*chemistry/physiology ; Point Mutation ; Protein Conformation ; Protein Multimerization ; Protein Subunits/chemistry/metabolism ; Staphylococcus aureus/chemistry
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 6
    Publication Date: 2018-11-03
    Description: Bufalin is a major cardiotonic compound in the traditional Chinese medicine, Chansu, prepared from toad skin secretions. Cell culture studies have suggested an anticancer potential involving multiple cellular processes, including differentiation, apoptosis, senescence, and angiogenesis. In prostate cancer cell models, P53-dependent and independent caspase-mediated apoptosis and androgen receptor (AR) antagonism have been described for bufalin at micromolar concentrations. Because a human pharmacokinetic study indicated that single nanomolar bufalin was safely achievable in the peripheral circulation, we evaluated its cellular activity within range with the AR-positive and P53 wild-type human LNCaP prostate cancer cells in vitro . Our data show that bufalin induced caspase-mediated apoptosis at 20 nmol/L or higher concentration with concomitant suppression of AR protein and its best-known target, PSA and steroid receptor coactivator 1 and 3 (SRC-1, SRC-3). Bufalin exposure induced protein abundance of P53 (not mRNA) and P21CIP1 ( CDKN1A ), G 2 arrest, and increased senescence-like phenotype (SA-galactosidase). Small RNAi knocking down of P53 attenuated bufalin-induced senescence, whereas knocking down of P21CIP1 exacerbated bufalin-induced caspase-mediated apoptosis. In vivo , daily intraperitoneal injection of bufalin (1.5 mg/kg body weight) for 9 weeks delayed LNCaP subcutaneous xenograft tumor growth in NSG SCID mice with a 67% decrease of final weight without affecting body weight. Tumors from bufalin-treated mice exhibited increased phospho-P53 and SA-galactosidase without detectable caspase-mediated apoptosis or suppression of AR and PSA. Our data suggest potential applications of bufalin in therapy of prostate cancer in patients or chemo-interception of prostate precancerous lesions, engaging a selective activation of P53 senescence. Mol Cancer Ther; 17(11); 2341–52. ©2018 AACR .
    Print ISSN: 1535-7163
    Electronic ISSN: 1538-8514
    Topics: Medicine
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  • 7
    Publication Date: 2018-05-12
    Description: Laser-driven high-harmonic generation provides the only demonstrated route to generating stable, tabletop attosecond x-ray pulses but has low flux compared to other x-ray technologies. We show that high-harmonic generation can produce higher photon energies and flux by using higher laser intensities than are typical, strongly ionizing the medium and creating plasma that reshapes the driving laser field. We obtain high harmonics capable of supporting attosecond pulses up to photon energies of 600 eV and a photon flux inside the water window (284 to 540 eV) 10 times higher than previous attosecond sources. We demonstrate that operating in this regime is key for attosecond pulse generation in the x-ray range and will become increasingly important as harmonic generation moves to fields that drive even longer wavelengths.
    Electronic ISSN: 2375-2548
    Topics: Natural Sciences in General
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  • 8
    Publication Date: 2018-03-06
    Description: Ribosome biogenesis in eukaryotes is a complicated process that involves association and dissociation of numerous assembly factors and snoRNAs. The yeast small ribosomal subunit is first assembled into 90S pre-ribosomes in an ordered and dynamic manner. Efg1 is a protein with no recognizable domain that is associated with early 90S particles. Here, we determine the crystal structure of Efg1 from Chaetomium thermophilum at 3.3 Å resolution, revealing a novel elongated all-helical structure. Efg1 is not located in recently determined cryo-EM densities of 90S likely due to its low abundance in mature 90S. Genetic analysis in Saccharomyces cerevisiae shows that the functional core of Efg1 contains two helical hairpins composed of highly conserved residues. Depletion of Efg1 blocks 18S rRNA processing at sites A1 and A2, but not at site A0, and production of small ribosomal subunits. Efg1 is initially recruited by the 5′ domain of 18S rRNA. Its absence disturbs the assembly of the 5′ domain and inhibits release of U14 snoRNA from 90S. Our study shows that Efg1 is required for early assembly and reorganization of the 5′ domain of 18S rRNA.
    Print ISSN: 0305-1048
    Electronic ISSN: 1362-4962
    Topics: Biology
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  • 9
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    German Medical Science GMS Publishing House; Düsseldorf
    In:  130. Kongress der Deutschen Gesellschaft für Chirurgie; 20130430-20130503; München; DOC13dgch736 /20130426/
    Publication Date: 2013-04-27
    Keywords: ddc: 610
    Language: English
    Type: conferenceObject
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  • 10
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Chinese Astronomy and Astrophysics 14 (1990), S. 262-272 
    ISSN: 0275-1062
    Keywords: Sun-Prominences-Spectra
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
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