GLORIA

GEOMAR Library Ocean Research Information Access

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
    Electronic Resource
    Electronic Resource
    Spectroscopic study of surfactant enhanced organometallic vapor phase epitaxy growth of GaInP (2001)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 90 (2001), S. 1040-1046 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Samples of GaxIn1−xP grown by organometallic vapor phase epitaxy on (001) GaAs substrates by addition of TESb demonstrating a lateral superlattice compositional modulation (CM) have been studied by low temperature polarized photoluminescence (PL), power dependent PL, and photoluminescence excitation (PLE) spectroscopy. Strong polarization is observed in the low temperature PL and PLE spectra at Sb concentrations below that where CuPtB ordering is removed and triple period ordering is produced. Low temperature polarized PL is shown to be the most sensitive optical technique for detecting the presence of CM. The radiative recombination mechanism at low temperature is excitonic, originating from the exponential tail of band gap states observed in the PLE spectra. From the measured band gaps, a continuum model of the band structure allows an estimate of an upper limit of the percent modulation present in the samples. Above Sb/III(v)=0.01, compositional modulation is the dominant factor determining the low temperature optical properties. The percent fluctuation of composition increases monotonically with increasing Sb during growth. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1378060
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    A new analytic approximation to atomic incoherent X-ray scattering intensities (1975)
    [S.l.] : International Union of Crystallography (IUCr)
    Acta crystallographica 31 (1975), S. 391-392 
    Details
    ISSN: 1600-5724
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: A new analytic approximation to atomic incoherent X-ray scattering intensities is proposed. Unlike other approximations in the literature, the present function has the correct asymptotic behaviour at both large and small values of s. Fits to the incoherent intensities calculated by Cromer are presented for all atoms from He through Am.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S056773947500085X
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Comparison of methods for conducting marine and estuarine sediment porewater toxicity tests—extraction, storage, and handling techniques (1995)
    Springer
    Archives of environmental contamination and toxicology 28 (1995), S. 69-77 
    Details
    ISSN: 1432-0703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Notes: Abstract A series of studies was conducted to compare different porewater extraction techniques and to evaluate the effects of sediment and porewater storage conditions on the toxicity of pore water, using assays with the sea urchin Arbacia punctulata. If care is taken in the selection of materials, several different porewater extraction techniques (pressurized squeezing, centrifugation, vacuum) yield samples with similar toxicity. Where the primary contaminants of concern are highly hydrophobic organic compounds, centrifugation is the method of choice for minimizing the loss of contaminants during the extraction procedure. No difference was found in the toxicity of pore water obtained with the Teflon® and polyvinyl chloride pressurized extraction devices. Different types of filters in the squeeze extraction devices apparently adsorbed soluble contaminants to varying degrees. The amount of fine suspended particulate material remaining in the pore water after the initial extraction varied among the methods. For most of the sediments tested, freezing and thawing did not affect the toxicity of porewater samples obtained by the pressurized squeeze extraction method. Pore water obtained by other methods (centrifugation, vacuum) and frozen without additional removal of suspended particulates by centrifugation may exhibit increased toxicity compared with the unfrozen sample. The toxicity of pore water extracted from refrigerated (4°C) sediments exhibited substantial short-term (days, weeks) changes. Similarly, sediment pore water extracted over time from a simulated amphipod solid-phase toxicity test changed substantially in toxicity. For the sediments tested, the direction and magnitude of change in toxicity of pore water extracted from both refrigerated and solid-phase test sediments was unpredictable.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00213971
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    facet.materialart.
    Unknown
    Cyclophilins and ER Redox Regulation [Protein Synthesis and Degradation] (2014)
    The American Society for Biochemistry and Molecular Biology (ASBMB)
    Details
    Publication Date: 2014-08-15
    Description: Protein folding within the endoplasmic reticulum is assisted by molecular chaperones and folding catalysts that include members of the protein-disulfide isomerase and peptidyl-prolyl isomerase families. In this report, we examined the contributions of the cyclophilin subset of peptidyl-prolyl isomerases to protein folding and identified cyclophilin C as an endoplasmic reticulum (ER) cyclophilin in addition to cyclophilin B. Using albumin and transferrin as models of cis-proline-containing proteins in human hepatoma cells, we found that combined knockdown of cyclophilins B and C delayed transferrin secretion but surprisingly resulted in more efficient oxidative folding and secretion of albumin. Examination of the oxidation status of ER protein-disulfide isomerase family members revealed a shift to a more oxidized state. This was accompanied by a 〉5-fold elevation in the ratio of oxidized to total glutathione. This “hyperoxidation” phenotype could be duplicated by incubating cells with the cyclophilin inhibitor cyclosporine A, a treatment that triggered efficient ER depletion of cyclophilins B and C by inducing their secretion to the medium. To identify the pathway responsible for ER hyperoxidation, we individually depleted several enzymes that are known or suspected to deliver oxidizing equivalents to the ER: Ero1αβ, VKOR, PRDX4, or QSOX1. Remarkably, none of these enzymes contributed to the elevated oxidized to total glutathione ratio induced by cyclosporine A treatment. These findings establish cyclophilin C as an ER cyclophilin, demonstrate the novel involvement of cyclophilins B and C in ER redox homeostasis, and suggest the existence of an additional ER oxidative pathway that is modulated by ER cyclophilins.
    Print ISSN: 0021-9258
    Electronic ISSN: 1083-351X
    Topics: Biology , Chemistry and Pharmacology
    Published by The American Society for Biochemistry and Molecular Biology (ASBMB)
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 5
    facet.materialart.
    Unknown
    Client Binding Sites of Calreticulin [Protein Synthesis and Degradation] (2016)
    The American Society for Biochemistry and Molecular Biology (ASBMB)
    Details
    Publication Date: 2016-09-10
    Description: Calreticulin is a lectin chaperone of the endoplasmic reticulum that interacts with newly synthesized glycoproteins by binding to Glc1Man9GlcNAc2 oligosaccharides as well as to the polypeptide chain. In vitro, the latter interaction potently suppresses the aggregation of various non-glycosylated proteins. Although the lectin-oligosaccharide association is well understood, the polypeptide-based interaction is more controversial because the binding site on calreticulin has not been identified, and its significance in the biogenesis of glycoproteins in cells remains unknown. In this study, we identified the polypeptide binding site responsible for the in vitro aggregation suppression function by mutating four candidate hydrophobic surface patches. Mutations in only one patch, P19K/I21E and Y22K/F84E, impaired the ability of calreticulin to suppress the thermally induced aggregation of non-glycosylated firefly luciferase. These mutants also failed to bind several hydrophobic peptides that act as substrate mimetics and compete in the luciferase aggregation suppression assay. To assess the relative contributions of the glycan-dependent and -independent interactions in living cells, we expressed lectin-deficient, polypeptide binding-deficient, and doubly deficient calreticulin constructs in calreticulin-negative cells and monitored the effects on the biogenesis of MHC class I molecules, the solubility of mutant forms of α1-antitrypsin, and interactions with newly synthesized glycoproteins. In all cases, we observed a profound impairment in calreticulin function when its lectin site was inactivated. Remarkably, inactivation of the polypeptide binding site had little impact. These findings indicate that the lectin-based mode of client interaction is the predominant contributor to the chaperone functions of calreticulin within the endoplasmic reticulum.
    Print ISSN: 0021-9258
    Electronic ISSN: 1083-351X
    Topics: Biology , Chemistry and Pharmacology
    Published by The American Society for Biochemistry and Molecular Biology (ASBMB)
    Location Call Number Limitation 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...