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  • Analytical Chemistry and Spectroscopy  (2,665)
  • Cell & Developmental Biology  (1,529)
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  • 1
    Electronic Resource
    Electronic Resource
    Total reflection x-ray fluorescence spectrometry of metal samples using synchrotron radiation at SSRLPresented at the European Conference on EDXRS. Myconos, Greece, 30 May-6 June 1992. (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    X-Ray Spectrometry 22 (1993), S. 277-280 
    Details
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: It was demonstrated that a total reflection x-ray fluorescence spectrometer, using monoenergetic synchrotron radiation as the primary x-ray source, is suitable to measure the concentration of transmutational elements in Cu and Fe metal matrices. In a typical irradiation of copper with 590 MeV protons or with spallation neutrons, where the damage dose is 0.4 dpa (displacement per atom), the calculated concentration of transmutational elements is Ni 25, Co 8 and Fe 8 μg g-1. The results show that the minimum detectable concentrations were lower than these values. The energy of the sychrotron radiation was set just below the K-edge energy of the matrix element, eliminating the large peak due to the matrix. As an example, in the case of a Cu (Z = 29) matrix, the minimum detectable concentration for Ni (Z = 28) was as low as 3 μg g-1. In order to check systematically the possible geometric arrangements of beam direction-reflector position-detector position, a new vacuum chamber was designed and tested. It provides all technical components for remote control of the adjustment procedure to align the reflector in total reflection geometry. Two ways of positioning the reflector in the beam, vertical to the plane of polarization and parallel to that plane, were investigated, to find the best excitation conditions and lowest limits of detection. A few pg corresponding to a concentration of ng g-1 of samples where the matrix can be easily removed as in aqueous or acidic solutions and 50 ng g-1 concentration of metals in a light matrix as in oil were found as detection limits.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/xrs.1300220419
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  • 2
    Electronic Resource
    Electronic Resource
    Comparison of 252californium plasma desorption and fast atom bombardment mass spectrometry for analysis of small peptides (1985)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 12 (1985), S. 380-387 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The data obtained with 252Cf plasma desorption (PD) and fast atom bombardment mass spectrometry of eight tri-, tetra- and pentapeptides were compared. Good spectra were obtained with 1-10 nmol of peptide. In both techniques molecular weight information was obtained. The PD mass spectra are often dominated by the cationized molecular ions in contrast to the fast atom bombardment (FAB) mass spectra, where cationization is rarely observed. Amino acid content is reflected in the immonium ions equally well in both techniques. The fragmentation patterns observed with the two techniques are almost identical. However, practical sequencing of peptides based on either FAB or PD mass spectrometry of underivatized peptides alone is difficult. This is due to the unpredictable and sometimes absent cleavage yield at certain peptide bonds. Another difficulty is the many simultaneous fragmentation pathways. However, for many peptides enough information is present to allow sequence determination for at least a major part of the molecule.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200120805
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  • 3
    Electronic Resource
    Electronic Resource
    Preparation of biological tissue sections for correlative ion, electron, and light microscopy (1984)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 1 (1984), S. 299-309 
    Details
    ISSN: 0741-0581
    Keywords: Electron microscopy ; Ion microscopy ; Correlative microscopy ; Electron probe microanalysis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: In order to correctly interpret the chemical images obtained using ion microscopy (IM), it is useful to correlate them with the information provided by conventional light microscopy (LM), secondary electron imaging (SEI), backscattered electron imaging (BEI), and electron probe microanalysis (EPMA). Accordingly, we have devised a technique of specimen preparation which allows for the application of several different microanalytical techniques to a single histologic section mounted on the same substrate. Sections are cut onto polyester plastic coverslips (devoid of peaks for any element with atomic number 〉 9 using EPMA) and studied by LM. After a light rotary coating with carbon (to prevent charging), the section can then be examined by SEI, BEI, and EPMA. Specific areas can be marked for IM study either with an objective-mounted pin tissue microlocater, or by placing small pieces of metal foil, cut in specific geometric shapes, over features of interest. After sputter-coating the sample with platinum, metal-free shadows are visible using a low-power reflected light microscope available on a typical IM sample chamber as a guide for ion beam placement. The conductive coatings also minimize specimen charging during IM. Post-IM light microscopy, SEI, and BEI are used to confirm the location of specific areas probed in the IM experiments and to provide information on differential ion-sputtering artifacts and tissue contaminants. This new correlative technique should permit better understanding of the images obtained with these diverse instruments.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1060010309
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  • 4
    Electronic Resource
    Electronic Resource
    Fast-atom bombardment mass spectrometry of new polydentate schiff bases. 1. The case of variously substituted mono-and bis-salicylaldimine derivatives (1994)
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 8 (1994), S. 111-119 
    Details
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: The mass spectrometric behaviour of ten variously substituted mono- and bis-salicylaldimine derivatives has been studied by fast-atom bombardment and metastable-ion studies. In general, well detectable protonated molecules are present and fragmentation processes mainly related to aldimine chain cleavages are evidenced. Interesting cyclization reactions leading to particularly stable product ions are discussed.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/rcm.1290080121
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  • 5
    Electronic Resource
    Electronic Resource
    Mass spectrometric studies on some macrocyclic, macrobicyclic and macroacyclic Schiff bases (1992)
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 6 (1992), S. 741-746 
    Details
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: The mass spectrometric behaviour of four macrocyclic, one macrobicyclic and one macroacyclic Schiff bases, obtained by one-step multiple condensation reactions of 2,6-diformyl-4-methylpropane, 1,3-diamino- 2,2-dimethylpropene, 1,5-diamino-3-oxapentane or tris-(2-aminoethyl) amine under fast-atom bombardment conditions, was studied in detail with the aid of mass-analyzed ion kinetic energy spectrometry. The mass spectrometric behaviour of a mononuclear macrobicy La(III) complex is also described.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/rcm.1290061206
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  • 6
    Electronic Resource
    Electronic Resource
    Plasma desorption time-of-flight mass spectrometric elucidation of the mechanisms of adhesion enhancement between plasma-treated PEEK-carbon composite and an epoxyamine adhesive (1995)
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 9 (1995), S. 1566-1571 
    Details
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Plasma desorption time-of-flight mass spectrometry (PD-TOFMS) using accelerated argon ions (9 MeV) has been successfully used for characterizing the surface modifications induced at the surface of poly(ether etherketone) (PEEK) by cold plasma treatments. While the intact polymer structure leads to the emission of negative ions from fragmentation of the repeat unit, the degradation of such a structure under plasma exposure gives rise to production of oxidized fragments. It is demonstrated that this production is highest for a plasma using a mixture of O2 and N2 (20:80), and that as a function of treatment duration, the rate of oxidation of the modified surface layer correlates with adhesive strength, at least in a first step. PD-TOFMS is used for analysis of the failure patterns of epoxyamine adhesive/PEEK/carbon composite in order to localize the fracture position. It is concluded that the increase of the cohesion of the interphase layer as a function of the plasma treatment duration leads to a shift from the interphase/PEEK interface to the bulk of the matrial.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/rcm.1290091520
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  • 7
    Electronic Resource
    Electronic Resource
    252Cf-plasma desorption and cesium-ion liquid secondary-ion mass spectrometric analysis of recombinant proteins (1991)
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 5 (1991), S. 81-85 
    Details
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: The keV Cs+ liquid secondary-ion mass spectrometry (LSIMS) and 252Cf-plasma desorption (PD) mass spectra of recombinant proteins in the 10-25 kDa mass range are compared. Both techniques showed comparable mass accuracy and sensitivity, and in the case of LSIMS, remarkably short analysis time. Analysis by the PD/nitrocellulose method demonstrated slightly higher sensitivity and relativity lower dependence on the salt and buffer content of the protein sample.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/rcm.1290050208
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  • 8
    Electronic Resource
    Electronic Resource
    Major influence of cell differentiation status on characteristics of proteoglycans synthesized by cultured rabbit renal proximal tubule cells: Role of insulin and dexamethasone (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 154 (1993), S. 175-191 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: To analyze the influence of epithelial cell differentiation and the effects of hormones on the characteristics of cell-associated and secreted proteoglycans (PGs), we studied their distribution, synthesis, and biochemical features in a model of renal proximal tubule cells in primary culture in which cell differentiation could be controlled by medium composition. In cells cultured in serum-free, hormonally defined medium supplemented with insulin and dexamethasone that exhibited a high degree of morphological and functional proximal differentiation (Ronco et al., 1990), cell-associated PGs were similar to those extracted in vivo by their size estimated by Sepharose CL-6B chromatography (Kav = 0.27, vs. 0.26), composition (heparan-sulfate), and localization in a continuous basal layer of extra-cellular matrix (ECM). In contrast, major quantitative and qualitative anomalies of cell-associated PGs were observed in poorly differentiated cells grown in 1% fetal calf serum-supplemented medium (FCS). PGs alterations included: (1) reduced and irregular expression of PGs at the cell basal pole, (2) a 2.8-fold decrease in [35S]-incorporation into cell-associated PGs, (3) a 3.1-fold increase in trypsin-releasable PGs, and (4) the emergence of a high MW PG composed exclusively of chondroitin-sulfate (CS) (Kav = 0.09 on Sepharose CL-6B) as well as of putative free CS-glycosaminoglycan (GAG) chains (Kav = 0.49 on Sepharose CL-6B). The same alterations were identified in the basal defined medium devoid of hormones but were partially or totally abolished by addition of insulin and dexamethasone, respectively. At variance with cell-associated PGs, production and biochemical features of secreted PGs were not influenced by cell differentiation status and medium composition. © 1993 Wiley-Liss, Inc.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041540121
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  • 9
    Electronic Resource
    Electronic Resource
    Middle ear cell line that maintains vectorial electrolyte transport (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 154 (1993), S. 615-622 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The middle ear epithelium plays a major role in keeping the temporal bone cavities fluid-free and air-filled, which is a mandatory condition to allow optimum transmission of the sound vibrations from the tympanic membrane to the inner ear. Previous works have recently established the absorptive function of the middle ear epithelium, using primary cultures derived from Mongolian gerbil (Meriones unguiculatus). Because of the paucity of cells as obtained by enzymatic digestion, we developed a middle ear cell line (MESV) using wild-type SV40 infection of primary culture of Mongolian gerbil's middle ear epithelial cells. Transformation was attested by nuclear expression of SV40 large T antigen, prolonged in vitro passages (presently beyond 50 passages), and tumor-inducing ability when subcutaneously injected in athymic mice. Transport properties were evaluated after the fifteenth passage. MESV cells retained most cardinal properties of the original middle ear epithelial cells: cell polarization was evidenced by the presence of mature junctional complexes that separate the cell membrane in two distinct domains, with apical microvilli at the luminal side, and by vectorial sodium transport responsible for the transepithelial lumen-negative potential difference (-9.3 ± 0.14 mV in culture conditions (n=9), -2.1 ± 0.25 mV after overnight growth factors and serum deprivation). Short-circuit current was, like in primary cultures, mainly related to a sodium transport occuring through amiloride-sensitive apical sodium channels, since apical addition of amiloride (10-5 M) reduced Isc from 7.0 = 1.4 to 0.6 ± 0.1 μA/cm2 (P 〈 0.01, n = 6). Cellular cAMP content was increased by isoproterenol and prostaglandin E2 from 40.5 ± 5.6 to 258.5 ± 17.3 and 55.6 ± 6.2 pmol/mg protein per 5 min, respectively (P 〈 0.05, n = 10). Isoproterenol and prostaglandin E2 increased Isc with very similar maximal effects: isoproterenol (10-4 M) increased Isc from 5.73 ± 0.31 to 12.77 ± 0.39 μA/cm2, while prostaglandin E2 increased Isc from 5.47 ± 0.21 to 12.87 ± 0.42 (n = 3). Since amiloride (10-5 M) abolished this stimulation, this may be related to an increase of the electrogenic sodium transepithelial transport. The MESV cell line could provide an interesting tool as a model of middle ear epithelial cells for the study of pathophysiological modulations of ion transport. © 1993 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041540321
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  • 10
    Electronic Resource
    Electronic Resource
    Cytogenetic study of parthenogenetically activated bovine oocytes matured in vivo and in vitro (1988)
    New York, NY : Wiley-Blackwell
    Gamete Research 20 (1988), S. 265-274 
    Details
    ISSN: 0148-7280
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Three experiments were performed to evaluate the potential for parthenogenetic activation of bovine oocytes in in vitro fertilization systems and to determine the chromosome complement of the resulting parthenogenotes. In the first experiment, immature oocytes from slaughtered cattles were matured in vitro in Defined Medium (DM) for 24 h to simulate in vitro fertilization conditions. Subsequently, a portion was fixed, and the remainder were transferred to rabbit oviducts. Oocytes were then cultured for 6-8 h or for 24 h with Colcemid present during the last 6 to 8 h and fixed on slides and examined. In the second experiment, mature oocytes were collected from the preovulatory follicles, and the oocytes were subjected to the same culture as in experiment I. In the third experiment, oocytes were treated as in experiment II, except that instead of transfer to rabbit oviducts, they were cultured an additional 48 h in vitro. In experiment I, 131 oocytes were fixed after culture in DM. Of the 79 oocytes analyzed in the pre-rabbit group, 71 (90%) were at the second meiotic metaphase (MII), and 8 (10%) were at pre-MII stage; none were activated. After transfer to rabbits, 291 were fixed. Of these, 80 were analyzed; 37 (46.3%) were MII, 7 (8.6%) were pre-MII, and 36 (45%) were activated. Of the 36 activated oocytes, 26 (72.2%) were haploid, 4 (11.1%) were diploid, 1 (12.8%) was tetraploid, and 5 (13.8%) were in the process of endoreduplication. In experiment II, 51 oocytes were fixed after culture in DM of which 36 (70.6%) could be analyzed; 30 (83.3%) were MII, and 6 (16.7%) were pre-MII. After culture in the rabbit, 68 were fixed of which 27 (39.7%) could be analyzed. Of these 27, 20 (74.1%) were MII, and 7 (25.9%) were activated; 6 were haploid, and 1 was endoreduplicating. In experiment III, 30 oocytes were fixed at the end of the culture period; only 10 could be analyzed of which 8 (80%) were MII and 2 (20%) were pre-MII. In all, 46% of in vitro and 26% of in vivo matured oocytes were activated, based on chromosomal analysis. Of those activated, the majority (74.4%) were haploid, suggesting that activation occurs at or after completion of MII. Endoreduplication appears to be one of the mechanisms leading to the formation of diploid and polyploid parthenogenotes.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1120200303
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