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Metal Used (metal + used)

Distribution by Scientific Domains

Polymers and Materials Science	33%
Life Sciences	33%

Selected Abstracts

A Novel Macromolecular Complex: Fabrication of Monodisperse Colloidal Microspheres by Precipitation Polymerization of Imine Chains and Concomitant Transition Metal Binding

ADVANCED MATERIALS, Issue 17 2003
H. Houjou
A series of monodisperse colloidal microspheres has been fabricated by precipitation polymerization of imine chains and concomitant transition metal binding. The resulting metal-bound polyimine microspheres (M-PIMSs, M = Co, Ni, Cu, or Zn, see Figure, which shows Zn-PIMSs) have characteristic diameters in the range from 0.5 to 1.4 ,m, depending on the metal used, and are of interest for applications in photonic devices. [source]

Diastereochemical differentiation of bicyclic diols using metal complexation and collision-induced dissociation mass spectrometry

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 12 2009
Jaana M. H. Pakarinen
Metal complex formation was investigated for di- exo -, di- endo - and trans -2,3- and 2,5-disubstituted trinorbornanediols, and di- exo - and di- endo - 2,3-disubstituted camphanediols using different divalent transition metals (Co2+, Ni2+, Cu2+) and electrospray ionization quadrupole ion trap mass spectrometry. Many metal-coordinated complex ions were formed for cobalt and nickel: [2M+Met]2+, [3M+Met]2+, [M,H+Met]+, [2M,H+Met]+, [M+MetX]+, [2M+MetX]+ and [3M,H+Co]+, where M is the diol, Met is the metal used and X is the counter ion (acetate, chloride, nitrate). Copper showed the weakest formation of metal complexes with di- exo -2,3-disubstituted trinorbornanediol yielding only the minor singly charged ions [M,H+Cu]+, [2M,H+Cu]+ and [2M+CuX]+. No clear differences were noted for cobalt complex formation, especially for cis -2,3-disubstituted isomers. However, 2,5-disubstituted trinorbornanediols showed moderate diastereomeric differentiation because of the unidentate nature of the sterically more hindered exo -isomer. trans -Isomers gave rise to abundant [3M,H+Co]+ ion products, which may be considered a characteristic ion for bicyclo[221]heptane trans -2,3- and trans -2,5-diols. To differentiate cis -2,3-isomers, the collision-induced dissociation (CID) products for [3M+Co]2+, [M+CoOAc]+, [2M,H+Co]+ and [2M+CoOAc]+ cobalt complexes were investigated. The results of the CID of the monomeric and dimeric metal adduct complexes [M+CoOAc]+ and [2M,H+Co]+ were stereochemically controlled and could be used for stereochemical differentiation of the compounds investigated. In addition, the structures and relative energies of some complex ions were studied using hybrid density functional theory calculations. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Design of Affinity Tags for One-Step Protein Purification from Immobilized Zinc Columns

BIOTECHNOLOGY PROGRESS, Issue 1 2000
Richard S. Pasquinelli
Affinity tags are often used to accomplish recombinant protein purification using immobilized metal affinity chromatography. Success of the tag depends on the chelated metal used and the elution profile of the host cell proteins. Zn(II)-iminodiacetic acid (Zn(II)-IDA) may prove to be superior to either immobilized copper or nickel as a result of its relatively low binding affinity for cellular proteins. For example, almost all Escherichiacoli proteins elute from Zn(II)-IDA columns between pH 7.5 and 7.0 with very little cellular protein emerging at pH values lower than 7.0. Thus, a large portion of the Zn(II)-IDA elution profile may be free of contaminant proteins, which can be exploited for one-step purification of a target protein from raw cell extract. In this paper we have identified several fusion tags that can direct the elution of the target protein to the low background region of the Zn(II)-IDA elution profile. These tags allow targeting of proteins to different regions of the elution profile, facilitating purification under mild conditions. [source]

Abscheidung von Palladium und Palladiumlegierungen mit hohen Schichtdicken für die Mikrosystemtechnik

MATERIALWISSENSCHAFT UND WERKSTOFFTECHNIK, Issue 2 2007
E. Günther
Palladium and palladium alloys; Heavy deposits are used; Microsystems technology; Internal stress; Graph of current density vs. potential Abstract Die Abscheidung von Metallen und Legierungen in Mikrostrukturen erfordert meist eine Schichtdicke größer als 100 ,m, die der Strukturhöhe entspricht. Für die Nutzung von Edelmetallen in Mikrosystemen ist die Abscheidung von spannungsarmen, rissfreien, porenfreien und duktilen Schichten notwendig. Da die kommerziell abgeschiedenen Edelmetallschichten nur bis etwa 10 ,m qualitätsgerecht abgeschieden werden können, sind geeignete Zusätze und Variation der Abscheidungsbedingungen erforderlich, um mikrosystemtaugliche Elektrolyte zu entwickeln. Charakterisierung der Schichteigenschaften, Parameter der Abscheidungstechnologie und Anwendungsbeispiele werden aufgeführt. Erste Ergebnisse werden vorgestellt und diskutiert. Deposition of Thick Palladium and Palladium Alloy Layers for Microsystems Technology Layers of metals and alloys deposited in microstructures usually require to be thicker than the 100 ,m which is the approximate height of the structure. The deposited form of noble metals used in microsystems must be non-stressed, ductile and free of cracks and pores. As the thickness of layers deposited from commercial noble metal electrolytes will rarely exceed 10 ,m without loss of quality, developing an electrolyte system suitable for microsystems involves finding appropriate additives and deposition parameters. Details are given of deposit characterisation, the parameters of the deposition technology and some practical examples. Initial results are presented and discussed. [source]

Burning mouth syndrome: the role of contact hypersensitivity

ORAL DISEASES, Issue 4 2009
R Marino
Background:, Burning mouth syndrome is a burning sensation or stinging disorder affecting the oral mucosa in the absence of any clinical signs or mucosal lesions. Some studies have suggested that burning mouth syndrome could be caused by the metals used in dental prostheses, as well as by acrylate monomers, additives and flavouring agents, although others have not found any aetiologic role for hypersensitivity to dental materials. Objective:, To evaluate the extent and severity of adverse reactions to dental materials in a group of patients with burning mouth syndrome, and investigate the possible role of contact allergy in its pathogenesis. Materials and methods:, We prospectively studied 124 consecutive patients with burning mouth syndrome (108 males; mean age 57 years, range 41,83), all of whom underwent allergen patch testing between 2004 and 2007. Results:, Sixteen patients (13%) showed positive patch test reactions and were classified as having burning mouth syndrome type 3 or secondary burning mouth syndrome (Lamey's and Scala's classifications). Conclusion:, Although we did not find any significant association between the patients and positive patch test reactions, it would be advisable to include hypersensitivity to dental components when evaluating patients experiencing intermittent oral burning without any clinical signs. [source]

The properties of the Mn, Ni and Pb transport operating at plasma membranes of cucumber roots

PHYSIOLOGIA PLANTARUM, Issue 3 2007
Magdalena Migocka
To avoid metal toxicity, plants have developed mechanisms including efflux of metal ions from cells and their sequestration into cellular compartments. In this report, we present evidence for the role of plasma membrane efflux systems in metal tolerance of cucumber roots. We have identified the plasma membrane-transport system participating in Cd, Pb, Mn and Ni efflux from the cytosol. Kinetic characterization of this proton-coupled transport system revealed that it is saturable and has a different affinity for each of the metal ions used (with Km 5, 7.5 and 0.1 mM for Mn, Ni and Pb, respectively). Treatment of cucumber roots with 100 ,M Cd prior to the transport measurements caused a great increase (over 250%) in Cd antiport activity in plasmalemma vesicles. After decreasing the metal concentration to 50 ,M we still observed a large increase (over 150%) of this activity in comparison with the control. Moreover, the addition of 50 ,M Cd to the external solution stimulated not only Cd antiport in the plasmalemma vesicles but also the antiport of other metals used in the experiments. Treatment of cucumber roots with 50 ,M Ni revealed a similar effect: the antiport activity of Cd, Mn, Ni and Pb was stimulated, although to a lesser extent in comparison with stimulation by Cd. The data indicate that the root plasma membrane antiporter system is stimulated by the exogenous presence of heavy metals. [source]