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
Filter
Collection
Keywords
Publisher
Years
  • 1
    facet.materialart.
    Unknown
    A chirped-pulse Fourier-transform microwave/pulsed uniform flow spectrometer. II. Performance and applications for reaction dynamics (2014)
    American Institute of Physics (AIP)
    Details
    Publication Date: 2014-12-06
    Description: This second paper in a series of two reports on the performance of a new instrument for studying chemical reaction dynamics and kinetics at low temperatures. Our approach employs chirped-pulse Fourier-transform microwave (CP-FTMW) spectroscopy to probe photolysis and bimolecular reaction products that are thermalized in pulsed uniform flows. Here we detail the development and testing of a new K a -band CP-FTMW spectrometer in combination with the pulsed flow system described in Paper I [J. M. Oldham, C. Abeysekera, B. Joalland, L. N. Zack, K. Prozument, I. R. Sims, G. B. Park, R. W. Field, and A. G. Suits, J. Chem. Phys.141, 154202 (2014)]. This combination delivers broadband spectra with MHz resolution and allows monitoring, on the μs timescale, of the appearance of transient reaction products. Two benchmark reactive systems are used to illustrate and characterize the performance of this new apparatus: the photodissociation of SO 2 at 193 nm, for which the vibrational populations of the SO product are monitored, and the reaction between CN and C 2 H 2 , for which the HCCCN product is detected in its vibrational ground state. The results show that the combination of these two well-matched techniques, which we refer to as chirped-pulse in uniform flow, also provides insight into the vibrational and rotational relaxation kinetics of the nascent reaction products. Future directions are discussed, with an emphasis on exploring the low temperature chemistry of complex polyatomic systems.
    Print ISSN: 0021-9606
    Electronic ISSN: 1089-7690
    Topics: Chemistry and Pharmacology , Physics
    Published by American Institute of Physics (AIP)
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 2
    facet.materialart.
    Unknown
    Transcriptionally repressed genes become aberrantly methylated and distinguish tumors of different lineages in breast cancer [Genetics] (2011)
    National Academy of Sciences
    Details
    Publication Date: 2011-03-16
    Description: Aberrant promoter hypermethylation is frequently observed in cancer. The potential for this mechanism to contribute to tumor development depends on whether the genes affected are repressed because of their methylation. Many aberrantly methylated genes play important roles in development and are bivalently marked in ES cells, suggesting that their aberrant methylation may reflect developmental processes. We investigated this possibility by analyzing promoter methylation in 19 breast cancer cell lines and 47 primary breast tumors. In cell lines, we defined 120 genes that were significantly repressed in association with methylation (SRAM). These genes allowed the unsupervised segregation of cell lines into epithelial (EPCAM+ve) and mesenchymal (EPCAM−ve) lineages. However, the methylated genes were already repressed in normal cells of the same lineage, and 〉90% could not be derepressed by treatment with 5-aza-2′-deoxycytidine. The tumor suppressor genes APC and CDH1 were among those methylated in a lineage-specific fashion. As predicted by the epithelial nature of most breast tumors, SRAM genes that were methylated in epithelial cell lines were frequently aberrantly methylated in primary tumors, as were genes specifically repressed in normal epithelial cells. An SRAM gene expression signature also correctly identified the rare claudin-low and metaplastic tumors as having mesenchymal characteristics. Our findings implicate aberrant DNA methylation as a marker of cell lineage rather than tumor progression and suggest that, in most cases, it does not cause the repression with which it is associated.
    Print ISSN: 0027-8424
    Electronic ISSN: 1091-6490
    Topics: Biology , Medicine , Natural Sciences in General
    Published by National Academy of Sciences
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 3
    facet.materialart.
    Unknown
    A chirped-pulse Fourier-transform microwave/pulsed uniform flow spectrometer. I. The low-temperature flow system (2014)
    American Institute of Physics (AIP)
    Details
    Publication Date: 2014-10-21
    Description: We report the development of a new instrument that combines chirped-pulse microwave spectroscopy with a pulsed uniform supersonic flow. This combination promises a nearly universal detection method that can deliver isomer and conformer specific, quantitative detection and spectroscopic characterization of unstable reaction products and intermediates, product vibrational distributions, and molecular excited states. This first paper in a series of two presents a new pulsed-flow design, at the heart of which is a fast, high-throughput pulsed valve driven by a piezoelectric stack actuator. Uniform flows at temperatures as low as 20 K were readily achieved with only modest pumping requirements, as demonstrated by impact pressure measurements and pure rotational spectroscopy. The proposed technique will be suitable for application in diverse fields including fundamental studies in spectroscopy, kinetics, and reaction dynamics.
    Print ISSN: 0021-9606
    Electronic ISSN: 1089-7690
    Topics: Chemistry and Pharmacology , Physics
    Published by American Institute of Physics (AIP)
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 4
    facet.materialart.
    Unknown
    Global patterns of marine megafauna bycatch [Ecology] (2014)
    National Academy of Sciences
    Details
    Publication Date: 2014-04-09
    Description: Recent research on ocean health has found large predator abundance to be a key element of ocean condition. Fisheries can impact large predator abundance directly through targeted capture and indirectly through incidental capture of nontarget species or bycatch. However, measures of the global nature of bycatch are lacking for air-breathing...
    Print ISSN: 0027-8424
    Electronic ISSN: 1091-6490
    Topics: Biology , Medicine , Natural Sciences in General
    Published by National Academy of Sciences
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 5
    facet.materialart.
    Unknown
    The thermodynamics of the elusive HO3 radical (2010)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 2010-06-05
    Description: The role of HO3 as a temporary reservoir of atmospheric OH radicals remains an open question largely because of the considerable uncertainty in the value of the dissociation energy of the HO-O2 bond (D0) or, equivalently, the standard enthalpy of formation of HO3 (Delta(f)H;{overline{);circ }}$$). Using a supersonic flow apparatus, we have observed by means of laser-induced fluorescence the decay of OH radicals in the presence of O2 at temperatures between 55.7 and 110.8 kelvin (K). Between 87.4 and 99.8 K, the OH concentration approached a nonzero value at long times, allowing equilibrium constants for the reaction with O2 to be calculated. Using expressions for the equilibrium constant from classical and statistical thermodynamics, and values of partition functions and standard entropies calculated from spectroscopic data, we derived values of D0 = (12.3 +/- 0.3) kilojoules per mole and Delta(f)H;{overline{);circ }}$$ (298 K) = (19.3 +/- 0.5) kilojoules per mole. The atmospheric implications of HO3 formation are therefore very slight.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Le Picard, Sebastien D -- Tizniti, Meryem -- Canosa, Andre -- Sims, Ian R -- Smith, Ian W M -- New York, N.Y. -- Science. 2010 Jun 4;328(5983):1258-62. doi: 10.1126/science.1184459.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Institut de Physique de Rennes, Equipe Astrochimie Experimentale, UMR 6251 du CNRS, Batiment 11c, Universite de Rennes 1, Campus de Beaulieu, 35042 Rennes Cedex, France. sebastien.le-picard@univ-rennes1.fr〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20522771" target="_blank"〉PubMed〈/a〉
    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
  • 6
    facet.materialart.
    Unknown
    Ocean-wide hotspots of shark and longliner overlap [Ecology] (2016)
    National Academy of Sciences
    Details
    Publication Date: 2016-02-10
    Description: Overfishing is arguably the greatest ecological threat facing the oceans, yet catches of many highly migratory fishes including oceanic sharks remain largely unregulated with poor monitoring and data reporting. Oceanic shark conservation is hampered by basic knowledge gaps about where sharks aggregate across population ranges and precisely where they overlap...
    Print ISSN: 0027-8424
    Electronic ISSN: 1091-6490
    Topics: Biology , Medicine , Natural Sciences in General
    Published by National Academy of Sciences
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 7
    facet.materialart.
    Unknown
    G1/S transition in normal human T-lymphocytes requires the nuclear protein encoded by c-myb (1989)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1989-07-14
    Description: Exposure of peripheral blood mononuclear cells (PBMC) to an 18-base c-myb antisense oligomer before mitogen or antigen stimulation resulted in almost complete inhibition of c-myb messenger RNA and protein synthesis and blockade of T lymphocyte proliferation. Expression of early and late activation markers, interleukin-2 receptor and transferrin receptor, respectively, by PBMC was unaffected by antisense oligomer exposure as was the expression of c-myc messenger RNA. In contrast, histone H3 messenger RNA levels and DNA content were selectively decreased. These results suggest that c-myb protein deprivation does not perturb T lymphocyte activation or early molecular events that may prepare the cell for subsequent proliferation. Rather, it appears to specifically block cells in late G1 or early S phase of the cell cycle.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Gewirtz, A M -- Anfossi, G -- Venturelli, D -- Valpreda, S -- Sims, R -- Calabretta, B -- CA01324/CA/NCI NIH HHS/ -- CA36896/CA/NCI NIH HHS/ -- CA46782/CA/NCI NIH HHS/ -- New York, N.Y. -- Science. 1989 Jul 14;245(4914):180-3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Medicine, Temple University School of Medicine, Philadelphia, PA 19140.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2665077" target="_blank"〉PubMed〈/a〉
    Keywords: Cell Division/drug effects ; DNA/biosynthesis ; Fluorescent Antibody Technique ; Gene Expression Regulation ; Humans ; Image Processing, Computer-Assisted ; *Interphase ; *Lymphocyte Activation/drug effects ; Oligonucleotides/pharmacology ; Oligonucleotides, Antisense ; Proto-Oncogene Proteins/biosynthesis/*genetics/physiology ; Proto-Oncogene Proteins c-myb ; Proto-Oncogenes ; RNA, Messenger/biosynthesis/*genetics ; Receptors, Interleukin-2/biosynthesis ; Receptors, Transferrin/biosynthesis ; T-Lymphocytes/*cytology/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
  • 8
    facet.materialart.
    Unknown
    Understanding reactivity at very low temperatures: the reactions of oxygen atoms with alkenes (2007)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 2007-07-07
    Description: A remarkable number of reactions between neutral free radicals and neutral molecules have been shown to remain rapid down to temperatures as low as 20 kelvin. The rate coefficients generally increase as the temperature is lowered. We examined the reasons for this temperature dependence through a combined experimental and theoretical study of the reactions of O(3P) atoms with a range of alkenes. The factors that control the rate coefficients were shown to be rather subtle, but excellent agreement was obtained between the experimental results and microcanonical transition state theory calculations based on ab initio representations of the potential energy surfaces describing the interaction between the reactants.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Sabbah, Hassan -- Biennier, Ludovic -- Sims, Ian R -- Georgievskii, Yuri -- Klippenstein, Stephen J -- Smith, Ian W M -- New York, N.Y. -- Science. 2007 Jul 6;317(5834):102-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Institut de Physique de Rennes, Laboratoire PALMS, UMR 6627 du CNRS-Universite de Rennes 1, Equipe Astrochimie Experimentale, Bat. 11c, Campus de Beaulieu, 35042 Rennes Cedex, France.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/17615352" target="_blank"〉PubMed〈/a〉
    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
  • 9
    facet.materialart.
    Unknown
    Chemistry. Arranging reactive meetings of cold radicals (2011)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 2011-12-17
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Sims, Ian R -- New York, N.Y. -- Science. 2011 Dec 16;334(6062):1506-7. doi: 10.1126/science.1215318.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Institut de Physique de Rennes, UMR CNRS-UR1 6251, Universite de Rennes 1, Rennes, France. ian.sims@univ-rennes1.fr〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22174238" target="_blank"〉PubMed〈/a〉
    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
  • 10
    facet.materialart.
    Unknown
    Science in Congress: Deceptive statistics-Response (2015)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 2015-08-01
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Rosenberg, Andrew A -- Branscomb, L M -- Eady, V -- Frumhoff, P C -- Goldman, G T -- Halpern, M -- Kimmell, K -- Kothari, Y -- Kramer, L D -- Lane, N F -- McCarthy, J J -- Phartiyal, P -- Rest, K -- Sims, R -- Wexler, C -- New York, N.Y. -- Science. 2015 Jul 31;349(6247):487. doi: 10.1126/science.349.6247.487-a.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Center for Science and Democracy, Union of Concerned Scientists, Cambridge, MA 02138, USA. arosenberg@ucsusa.org. ; University of California, San Diego, La Jolla, CA 92093, USA. ; Conservation Law Foundation, Boston, MA 02110, USA. ; Union of Concerned Scientists, Cambridge, MA 02138, USA. ; Center for Science and Democracy, Union of Concerned Scientists, Cambridge, MA 02138, USA. ; William and Flora Hewlett Foundation, Menlo Park, CA 94025, USA. ; Baker Institute of Public Policy, Rice University, Houston, TX 77005, USA. ; Harvard University, Cambridge, MA 02138, USA. ; Seattle, WA 98101, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26228136" target="_blank"〉PubMed〈/a〉
    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
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...