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  • 1
    Electronic Resource
    Electronic Resource
    Organometallic Complexes with Biological Molecules: VIII. Synthesis, Solid State and in vivo Investigation of Triorganotin(IV) Derivatives of L-Homocysteic Acid (1997)
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 11 (1997), S. 601-616 
    Details
    ISSN: 0268-2605
    Keywords: triorganotin(IV) ; L-homocysteic acid ; infrared ; Mössbauer ; NMR ; sea urchin ; Paracentrotus lividus (Echinodermata) ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Several new triorganotin(IV) derivatives of L-homocysteic acid (L-HCAH) with formula R3Sn(L-HCA) (R=Me, nBu, Ph) have been synthesized. Their solid-state configurations were determined by IR and Mössbauer spectroscopy. The tin(IV) atom is five-coordinated in all the complexes, with the L-homocysteic acid behaving as a monoanionic bidentate ligand coordinating the tin(IV) atom through a chelating or bridging carboxylate group. The sulfonate (SO3-) and NH3+ groups of L-homocysteic acid maintain their free acid configuration and hence do not participate to the coordination of the tin(IV) atom. Coordination hypotheses have been checked through the correlation between the Mössbauer parameter isomer shift, δ, and partial atomic charge on the tin atoms, QSn, performed, for all the new organotin(IV) compounds, on the basis of an equalization procedure applied to idealized trigonal-bipyramidal structures for R3Sn(L-HCA).1H and 13C NMR spectra of the complexes show that pentacoordination of the tin atom, with R groups in the equatorial plane of a trigonal bipyramid, is retained in DMSO solution. The NMR data confirm also that the uncoordinated NH3+ group of the ligand is still present in solution.Results gathered after exposure of two- to four-cell embryos of the sea urchin Paracentrotus lividus (Echinodermata) to the triorganotin(IV) L-homocysteate derivatives as well as to the parent triorganotin(IV) chlorides document cytotoxicity of the complexes, while free L-homocysteic acid exerts no significant toxic activity. The trimethyltin(IV) L-homocysteate derivative seems to exert a lower cytotoxicity than the tributyl- and triphenyl-tin(IV) ones. Different structural lesions have been identified by comparative analysis of mitotic chromosomes from untreated embryos (negative controls) and embryos treated with triorganotin(IV) L-homocysteate derivatives, such as (1) suppression of the stretch among sister chromatids at the beginning of anaphase stage; (2) deeply stained zones mainly located at the telomeric regions of chromosomes; (3) arm breakages; and (4) chromosome bridges among daughter chromosomes at anaphase stage. A colchicine-like effect of triorganotin(IV) L-homocysteate derivatives was observed. © 1997 John Wiley & Sons, Ltd.
    Additional Material: 20 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    Identifying human platelet glycoproteins IIb and IIIa by capillary electrophoresis (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 1468-1474 
    Details
    ISSN: 0173-0835
    Keywords: Glycoproteins ; Capillary electrophoresis ; Glanzmann's thrombasthenia ; Platelet membrane ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Glanzmann thrombasthenia (GT) is an inherited hemorrhagic defect due to a failure of the platelet membrane glycoprotein (GP) IIb-IIIa complex. Capillary electrophoresis (CE) analysis of solubilized platelet membranes from normal individuals showed the presence of two peaks with a migration time of 27 and 29 min, respectively. An excellent run-to-run and day-to-day reproducibility of the technique (〈 1% variation of the retention time) was documented. Using an automated Ferguson method, the apparent molecular masses were 100.0 kDa and 138.5 kDa, respectively. Immunoprecipitation with monoclonal antibodies anti-GP IIIa (B59.2.1) and anti-IIb (61.9.1.3) showed the two peaks as IIIa and IIb, respectively. Electropherograms of a GT young man showed the lack of both peaks. Less than 50% of each peak was present in his parents. Polyacrylamide gel electrophoresis (PAGE), immunoblotting, and flow cytometry analyses showed that GP IIb and IIIa were undetectable in the platelet membranes from the propositus, half of the normal amount being present in both parents. These findings indicate CE to be a rapid, sensitive and reliable tool to investigate patients with abnormalities of the GP IIb-IIIa complex.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150190842
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  • 3
    Electronic Resource
    Electronic Resource
    Organometallic complexes with biological molecules. IX. Diorgano- and triorgano-tin(IV)[meso-tetra (4-sulfonatophenyl)porphinate] derivatives: solid-state and solution-phase structural aspects and in vivo effects (1997)
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 11 (1997), S. 707-719 
    Details
    ISSN: 0268-2605
    Keywords: organotin(IV) ; porphine ; Mössbauer ; NMR ; development ; Ascidiaceae ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Diorgano- and triorgano-tin(IV) derivatives of meso-tetra(4-sulfonatophenyl)porphine (H4TPPS) with general formula (R2Sn)2TPPS and (R3Sn)4TPPS (TPPS4-=[meso-tetra(4-sulfonatophenyl)porphinate]4-, R=Me, Bu, Ph) have been obtained and their solid-state configuration inferred on the basis of IR and Mössbauer spectroscopy, while solution-phase studies have been carried out by 1H and 13C NMR in DMSO-d6, together with determination of the in vivo cytotoxicity of the new derivatives towards embryonic development of Ciona intestinalis. In particular, octahedral and trigonal-bipyramidal eq-R3Sn polymeric configurations are proposed, in the solid state, respectively for (R2Sn)2TPPS and (R3Sn)4TPPS complexes, with the arylsulfonate groups behaving as monoanionic bidentate bridging ligands.The 1H and 13C NMR data lead to the conclusion that the metal-to-ligand ratio (2:1 or 4:1), binding site (the sulfonato-group oxygens), and the coordination polyhedron around the metal (trans-octahedral or trigonal-bipyramidal) found in the solid state are preserved in solution. © 1997 John Wiley & Sons, Ltd.
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  • 4
    Electronic Resource
    Electronic Resource
    Tetramethylthiuram disulfide and 2-mercaptobenzothiazole as binary accelerators in sulfur vulcanization. II. Exchange reactions between the accelerators and their zinc salts in the absence of rubber (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 58 (1995), S. 1053-1061 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Exchange reactions between tetramethylthiuram disulfide, 2-mercaptobenzothiazole, and sulfur in the presence of ZnO were studied by heating powdered mixes to vulcanization temperatures at a preprogrammed rate in a DSC. The reaction was stopped at points along the thermal curve and the mixture was analyzed. Sulfide exchange reactions between the accelerators leads to a mixed accelerator and dimethyldithiocarbamic acid that is trapped by ZnO to give the zinc accelerator complex bis(dimethyldithiocarbamato)zinc (II). Exchange also occurs between the accelerators and ligands on both the thiuram and benzothiazole zinc accelerator complexes. Zinc complexes containing ligands of both accelerators were synthesized. These showed little interaction on being heated with sulfur, but on dissolution yielded a spectrum of products similar to that obtained in the other system containing zinc. Reactions to account for changes in the spectrum of products on heating different mixes of these curatives to different temperatures are discussed. © 1995 John Wiley & Sons, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1995.070580612
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  • 5
    Electronic Resource
    Electronic Resource
    Tetramethylthiuram disulfide and 2-mercaptobenzothiazole as binary accelerators in sulfur vulcanization. IV. Vulcanization of polyisoprene in the presence of ZnO (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 62 (1996), S. 647-653 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Polyisoprene was vulcanized with binary accelerator systems comprising mixtures of the zinc salts of tetramethylthiuram disulfide (TMTD) and 2-mercaptobenzothiazole (MBT). Samples were heated in a DSC at a programmed rate, the reaction was stopped at points along the thermal curve, and the system was analyzed. Extractable curatives and reaction intermediates were analyzed by HPLC and the crosslink density of samples measured by swelling. DSC curves for the different systems displayed similar characteristics and their similarity to the curve obtained with the zinc salt of TMTD rather than to the curve obtained with the zinc salt of MBT suggested that the reaction was dominated by the former accelerator. This conclusion was supported by HPLC analyses of extractable curatives. A reaction mechanism for the binary system is discussed. © 1996 John Wiley & Sons, Inc.
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  • 6
    Electronic Resource
    Electronic Resource
    Tetramethylthiuram disulfide and 2-mercaptobenzothiazole as binary accelerators in sulfur vulcanization. I. Exchange reactions between the accelerators and sulfur in the absence of rubber (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 57 (1995), S. 1391-1407 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Exchange reactions between tetramethylthiuram disulfide, 2-mercaptobenzothizole, and sulfur were studied by heating powdered mixes to vulcanization temperatures at a programmed rate in a DSC. The reaction was stopped at points along the thermal curve and the mixture was analyzed by HPLC. On dissolution, even unheated samples undergo a sulfide exchange reaction leading to a mixed accelerator, while polysulfides of the thiuram and mixed accelerator form in low concentrations. On heating, higher concentrations of these polysulfides are formed, particularly in the presence of elemental sulfur. Dimethyldithiocarbamic acid, formed in the exchange, influences the product spectrum if it remains trapped in the DSC pan. Tetramethylthiourea is formed only at elevated temperatures when dimethylamine, a degradation product of the acid, is trapped in the DSC pan. A series of reactions is proposed to explain the product spectrum obtained under different conditions. © 1995 John Wiley & Sons, Inc.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1995.070571115
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  • 7
    Electronic Resource
    Electronic Resource
    Tetramethylthiuram disulfide and 2-mercaptobenzothiazole as binary accelerators in sulfur vulcanization. III. Vulcanization of polyisoprene in the absence of ZnO (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 62 (1996), S. 1057-1066 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Polyisoprene was vulcanized with the binary accelerator system tetramethylthiuram disulfide-2-mercaptobenzothiazole (TMTD-MBT) in the absence of ZnO. Samples were heated in a DSC at a programmed rate, the reaction was stopped at points along the thermal curve, and the system was analyzed. Extractable curatives and reaction intermediates were analyzed by HPLC and the crosslink density of samples measured by swelling. Two cross-linking reaction sequences were identified, the first being initiated by polysulfides of the mixed accelerator N,N-dimethyldithiocarbamylbenzothiazole disulfide, and the second by MBT. All the TMTD is consumed in the first reaction sequence. Synergism of the reaction is discussed in terms of recent work detailing a reaction mechanism for TMTD-accelerated vulcanization. © 1996 John Wiley & Sons, Inc.
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  • 8
    Electronic Resource
    Electronic Resource
    Silicone breast implants: The role of immune system on capsular contracture formation (1995)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 29 (1995), S. 197-202 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: We evaluated the role of the immune system in the pathogenesis of the periprosthetic capsular contracture, the most frequently occurring complication following the implant of silicone prostheses. Peripheral blood samples from 22 patients with silicone-gel-filled implants were examined. In all cases a capsule was felt by palpation, and it was classified according to the Baker scale. Ten patients (group 1) had a Baker 2 contracture, and 12 (group 2) had severe contracture rated 3 and 4. The cells positive to antigens CD3, CD4, CD8, HLA-DR, CD19, CD25, CD57, CD16, and CD14, and the cytotoxic activity of the lymphocytes on target cells K562 were assessed by cytofluorimetric analysis. At time 0 there were no statistically significant differences between patients and normal subjects, nor between the two groups. At 48 h, the group 2 patients had a number/mm3 of cells CD57 + significantly higher than both group 1 and control group (P 〈 .05). In group 1 patients, the cytotoxic activity was similar to that of normal subjects, whereas in group 2 it was significantly increased, in respect to both the controls (P 〈 .05) and group 1 (P 〈 .001). In all groups, the contact of the lymphocytes with the silicone extract did not modify either the antigen expression or the lymphocyte functional activity. On the basis of these results we hypothesize the involvement of the immune system in the formation of the capsular contracture around the prosthesis. © 1995 John Wiley & Sons, Inc.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820290209
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  • 9
    Electronic Resource
    Electronic Resource
    Assessment of viability and proliferation of in vivo silicone-primed lymphocytes after in vitro re-exposure to silicone (1995)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 29 (1995), S. 583-590 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The functional response of peripheral blood lymphocytes isolated from 22 patients with silicone gel-filled breast implants was assessed after in vitro re-exposure to silicone. Using cell culture test methods to quantify proliferation and viability and/or activation of lymphocyte microcultures, i.e., the uptake of tritiated thymidine (3H-TdR uptake test) and the reduction of formazan salts (MTT assay), interesting data were obtained. Peripheral blood lymphocytes purified from patients wearing silicone gel-filled breast implants react in vitro to silicone showing a statistically significant increase of both proliferation and viability, while healthy subjects do not respond on in vitro exposure to silicone. Differences resulted even more statistically significant when patients were divided into two groups depending on the type of surgery they underwent: patients with breast augmentation for aesthetic reasons seem to have an increased responsiveness in vitro to silicone compared to patients who experienced a reconstructive surgery of the breast. Although they are still preliminary, being referred to a limited population, these results suggest that the lymphocytes of patients with silicone gel-filled breast implants could be sensitized in vivo toward silicone; the re-exposure of these cells to silicone leads to a higher functional response which could be looked for by using quantitative in vitro test methods. © 1995 John Wiley & Sons, Inc.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820290505
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  • 10
    Electronic Resource
    Electronic Resource
    Tin(IV), Monomethyltin(IV), and Dimethyltin(IV) Complexes with thiol sulfur and heterocyclic nitrogen donors: Molecular dynamics and structure by 119Sn mössbauer spectroscopyDedicated to Professor Friedo Huber on his 65th Birthday (1995)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 621 (1995), S. 89-96 
    Details
    ISSN: 0044-2313
    Keywords: Tin complexes ; thiolated ligands ; 119Sn Mössbauer spectra ; molecular dynamics ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zinn(IV)-, Monomethylzinn(IV)- und Dimethylzinn(IV)-Komplexe mit Thiolschwefel- und heterocyclischen Stickstoff-Donatoren: Moleküldynamik und Struktur bei 119Sn-Mössbauer-SpektrenDie Moleküldynamik der Komplexe Sn(SPyN)4 (1), SnCl2(SPyN)2 (2), MeSn(SPy)3 (3), MeSnCl(SPyN)2 (4), Me2Sn(TCy)2 (5), Me2SnCl(TOx) (6) und Me2Sn(TUr) (7) (HSPy = 2-Mercaptopyridin; HSPyN = 2-Mercaptopyrimidin; HTCy = 2-Thiocytosin; HTOx = 8-Thiochinolin; H2TUr = 2-Thiouracil) wurde mit 119Sn-Mössbauer-Spektroskopie bei verschiedenen Temperaturen untersucht. Die Flächen unter den Resonanzlinien wurden als Funktion der Temperatur bestimmt und daraus die Debye-Temperaturen, die cut-off-Frequenzen wie auch die rückstoßfreien Anteile (Lamb-Mössbauer-Faktor) und die mittleren quadratischen Auslenkungen der 119Sn-Atome berechnet. Durch Fingerprintvergleiche auf Grund von Literaturdaten wurden monomere Strukturen den Komplexen (1) bis (4) und (6) zugeordnet, während (5) und (7) an der Grenze monomer eindimensionaler Polymerer liegen. Die Ergebnisse werden auf der Basis bekannter Kristall- und Molekülstrukturen diskutiert. Die Umgebung der Zinnatome wird durch Punktladungsmodell-Berechnungen von Kernquadrupolaufspaltungs-Parametern simuliert; Molekülstrukturen für die Komplexe (5) bis (7), von denen keine Röntgendaten verfügbar sind, werden vorgeschlagen.
    Notes: The molecular dynamics of the complexes Sn(SPyN)4 (1), SnCl2(SPyN)2 (2), MeSn(SPy)3 (3), MeSnCl(SPyN)2 (4), Me2Sn(TCy)2 (5), Me2SnCl(TOx) (6), and Me2Sn(TUr) (7) [HSPy = 2-mercaptopyridine; HSPyN = 2-mercaptopyrimidine; HTCy = 2-thiocytosine; HTOx = 8-thioquinoline; H2TUr = 2-thiouracil] has been investigated by variable temperature 119Sn Mössbauer spectroscopy. The area under the resonant peaks has been determined as function of temperature, from which Debye temperatures and cut-off frequencies, as well as recoil-free fractions (Lamb Mössbauer factor) and mean square displacements of 119Sn, have been calculated. By fingerprint procedures on the basis of literature data, monomeric structures are attributed to complexes (1)-(4) and (6), while (5) and (7) lie in the borderline monomersmonodimensional polymers. The results are discussed on the basis of known crystal and molecular structures. The nature of the environment of tin atoms has been simulated by point-charge model calculations of nuclear quadrupole splitting parameters; molecular structures are proposed for complexes (5)-(7), where no X-ray diffractometric data are available.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19956210116
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