177,140 research outputs found
The role of iron and copper on the oligomerization dynamics of DR_2577, the main S-layer protein of deinococcus radiodurans
No full textSurface (S)-layers are cryptic structures that coat the external surface of the bacterial cell in many species. The paracrystalline regularity of the S-layer is due to the self-assembling of one or more protein units. The property of self-assembling seems to be mediated by specific topologies of the S-layer proteins as well as the presence of specific ions that provide support in building and stabilizing the bi-dimensional S-layer organization. In the present study, we have investigated the self-assembling mechanism of the main S-layer protein of Deinococcus radiodurans (DR_2577) finding an unusual role played by Fe3+ and Cu2+ in the oligomerization of this protein. These findings may trace a structural and functional metallo-mediated convergence between the role of these metals in the assembling of the S-layer and their well-known roles in protecting against oxidative stress in D. radiodurans
Preparation Rapide et Simplifiee de l’Echantillon sous Champ Micro-ondes pour la Speciation des Metaux
No full textAppropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
Characterization of the aerosol produced by infrared femtosecond laser ablation of polyacrylamide gels for the sensitive inductively coupled plasma mass spectrometry detection of selenoproteins
No full textA 2D high repetition rate femtosecondlaserablation strategy (2-mm wide lane) previously developed for the detection of selenoproteins in gel electrophoresis by inductively coupled plasma mass spectrometry was found to increase signal sensitivity by a factor of 40 compared to conventional nanosecond ablation (0.12-mm wide lane) [G. Ballihaut, F. Claverie, C. Pécheyran, S. Mounicou, R. Grimaud and R. Lobinski, Sensitive Detection of Selenoproteins in Gel Electrophoresis by High Repetition Rate FemtosecondLaserAblation-Inductively Coupled Plasma Mass Spectrometry, Anal. Chem. 79 (2007) 6874–6880]. Such improvement couldn't be explained solely by the difference of amount of material ablated, and then, was attributed to the aerosol properties. In order to validate this hypothesis, the characterization of the aerosolproduced by nanosecond and high repetition rate femtosecondlaserablation of polyacrylamidegels was investigated. Our 2D high repetition rate femtosecondlaserablation strategy of 2-mm wide lane was found to produce aerosols of similar particle size distribution compared to nanosecond laserablation of 0.12-mm wide lane, with 38% mass of particles < 1 µm. However, at high repetition rate, when the ablated surface was reduced, the particle size distribution was shifted toward thinner particle diameter (up to 77% for a 0.12-mm wide lane at 285 µm depth). Meanwhile, scanning electron microscopy was employed to visualize the morphology of the aerosol. In the case of larger ablation, the fine particles ejected from the sample were found to form agglomerates due to higher ablation rate and then higher collision probability. Additionally, investigations of the plasma temperature changes during the ablation demonstrated that the introduction of such amount of polyacrylamidegel particles had very limited impact on the ICP source (ΔT~ 25 ± 5 K). This suggests that the cohesion forces between the thin particles composing these large aggregates were weak enough to have negligible impact on the ICPMS detection
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Reactivity of anticancer metallodrugs with serum proteins: New insights from size exclusion chromatography-ICP-MS and ESI-MS
No full textA method based on the coupling of high resolution size-exclusion liquid chromatography using a polymer stationary phase with inductively coupled plasma mass spectrometry was developed to study the interactions of two metallodrugs - cisplatin and RAPTA-T - with the serum proteins albumin and transferrin. In contrast to previous approaches, the technique allowed the total recovery of the metals from the column and was able to discriminate between the different species of the metallodrugs and their complexes with the proteins at femtomolar detection levels. Metal binding was found to be dependent on the protein concentration and on the incubation time of the sample. Cisplatin was found to bind the serum proteins to the same extent, whereas RAPTA-T showed marked preference for transferrin. The affinity of the ruthenium complex for holo-transferrin was higher than for the apo-form suggesting a cooperative iron-mediated metal binding mechanism. RAPTA-T binding to holo-transferrin was further investigated by electrospray mass spectrometry using both the intact protein and a model peptide mimicking the iron-binding pocket. © 2010 The Royal Society of Chemistry
Accuracy and precision of lead isotope ratios in wines measured by axial inductively coupled plasma time of flight mass spectrometry. [Erratum to document cited in CA133:192180].
No full textInternational audienceThe order of the authors has been cor. The addresses of the authors are as follows: Xiaodan Tian, Hakan Emteborg, and Freddy C. Adams: Micro and Trace Anal. Center, (MiTAC), University of Antwerp (UIA), Universiteitsplein 1, B-2610 Antwerp, Belgium; Mireille Barbaste: DGCC RF, 351 Cours de la Liberation, 33405 Talence Cedex, France; Ryszard Lobinski: CNRS 5034, Helioparc 2, av. Pr. Angot, 64053 Pau, France; Ludwik Halicz: Department of Earth Sciences, University of Oxford, UK OX1 3PR and Geol. Survey of Israel, 30 Malkhey Israel St., 95501 Jerusalem, Israel; and Albert Galy: Department of Earth Sciences, University of Oxford, UK OX1 3PR. [on SciFinder(R)
Letter from R. R. Zellick, Assistant Trust Officer, Anglo California National Bank of San Francisco, to Joseph R. Goodman, October 2, 1942
No full textLetter from R. R. Zellick, Assistant Trust Officer at The Anglo California National Bank of San Francisco, to Joseph R. Goodman, regarding property owned by Dave Tatsuno. Zellick mentions a dispute between current tenants and Tatsuno, and that Tatsuno has asked Goodman to help locate trustworthy tenants.Personal correspondence, organizational records, government documents, publications, and other papers created or collected by Joseph R. Goodman documenting the forced removal and incarceration of Japanese Americans during World War II, as well as organized resistance to incarceration. Included in the collection are records of the Japanese Young Men's Christian Association and the Japanese American Citizens' League in San Francisco, including papers of the Japanese YMCA's executive secretary Lincoln Kanai; Sakai family papers; Goodman's correspondence to and from Japanese American incarcerees, organizations opposing forced removal and incarceration of Japanese Americans, the War Relocation Authority, and others; publications, photographs, and ephemera from the Topaz Relocation Center, where Goodman taught high school; War Relocation Authority records and publications; and newspaper clippings, pamphlets, and reports about forced removal and incarceration created by various government, religious, and civic organizations, in California and nationwide
Advanced Techniques for Bioinorganic and Environmental Speciation Analysis for Heavy Metals
No full textInternational audienceA review with 33 refs. concerning advanced techniques for bio-inorg. and environmental speciation anal. for heavy metals is given. Topics discussed include: metals and species of interest ( Sb, Cd, Cu, Zn, Cr, Pb, Hg); instrumental aspects (purge-and-trap thermal desorption, gas chromatog.-based, liq. chromatog.-based, and electrophoretic techniques); sample pretreatment for speciation anal. (sepn. from sample matrix, derivatization, pre-concn.); and speciation of individual elements (Cr, Pb, Hg, Sn, porphyrin-bound elements, metalloprotein-bound elements). [on SciFinder(R)
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