101
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Yu XQ, Sun JP, Tang K, Li H, Huang XJ, Dupont L, Maier J. Reversible lithium storage in LiF/Ti nanocomposites. Phys Chem Chem Phys 2009; 11:9497-503. [DOI: 10.1039/b908149f] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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102
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Alexandrov VE, Kotomin EA, Maier J, Evarestov RA. Ab initio modeling of spin and charge ordering and lattice dynamics in CaFeO3 crystals. J Chem Phys 2008; 129:214704. [DOI: 10.1063/1.3030976] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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103
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Levi M, Aurbach D, Maier J. Electrochemically driven first-order phase transitions caused by elastic responses of ion-insertion electrodes under external kinetic control. J Electroanal Chem (Lausanne) 2008. [DOI: 10.1016/j.jelechem.2008.09.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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104
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Kotomin EA, Zhukovskii YF, Maier J. Atomistic Modeling of a New Storage. Z Anorg Allg Chem 2008. [DOI: 10.1002/zaac.200870093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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105
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Kaskhedikar NA, Karatas Y, Cui G, Wiemhoefer HD, Maier J. Electrochemical study of nanocomposite electrolytes based on borate esters. Z Anorg Allg Chem 2008. [DOI: 10.1002/zaac.200870085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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106
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Kaskhedikar NA, Federov V, Simon A, Maier J. Expanded graphite as anode for lithium ion battery. Z Anorg Allg Chem 2008. [DOI: 10.1002/zaac.200870084] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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107
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Cui G, Kaskhedikar N, Hu Y, Maier J. Nanocomposites of IV Element (Germanium and Silicon) and Carbon for a Li-Storage Material. CHEM-ING-TECH 2008. [DOI: 10.1002/cite.200750755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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108
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Hennig C, Werner A, Marquardt M, Bluhm T, Kroiss H, Kühner G, Heimann P, Maier J, Riemann H, Zilker M. Continuous data acquisition with online analysis for the Wendelstein 7-X magnetic diagnostics. FUSION ENGINEERING AND DESIGN 2008. [DOI: 10.1016/j.fusengdes.2007.09.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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109
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Bluhm T, Heimann P, Hennig C, Kroiss H, Kühner G, Maier J, Riemann H, Zilker M. Data access and its implementation at Wendelstein 7-X. FUSION ENGINEERING AND DESIGN 2008. [DOI: 10.1016/j.fusengdes.2007.11.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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110
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Heimann P, Bluhm T, Hennig C, Kroiss H, Kühner G, Maier J, Riemann H, Zilker M. Database structures and interfaces for W7-X. FUSION ENGINEERING AND DESIGN 2008. [DOI: 10.1016/j.fusengdes.2007.08.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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111
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Maier J, van Steeg H, van Oostrom C, Paschke R, Weiss RE, Krohn K. Iodine deficiency activates antioxidant genes and causes DNA damage in the thyroid gland of rats and mice. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2007; 1773:990-9. [PMID: 17467074 DOI: 10.1016/j.bbamcr.2007.03.011] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2007] [Revised: 03/16/2007] [Accepted: 03/19/2007] [Indexed: 01/17/2023]
Abstract
Because thyroid nodules are frequent in areas with iodine deficiency the aim of this study was to characterise molecular events during iodine deficiency that could explain mutagenesis and nodule formation. We therefore studied gene expression of catalytic enzymes prominent for H(2)O(2) detoxification and antioxidative defence, quantified DNA oxidation and damage as well as spontaneous mutation rates (SMR) in mice and rats fed an iodine controlled diet. Antioxidative enzymes such as superoxide dismutase 3, glutathione peroxidase 4 and the peroxiredoxins 3 and 5 showed increased mRNA expression, which indicates increased radical burden that could be the cause of additional oxidized base adducts found in thyroidal genomic DNA in our experiments of iodine deficiency. Furthermore, the uracil content of thyroid DNA was significantly higher in the iodine-deficient compared to the control group. While SMR is very high in the normal thyroid gland it is not changed in experimental iodine deficiency. Our data suggest that iodine restriction causes oxidative stress and DNA modifications. A higher uracil content of the thyroid DNA could be a precondition for C-->T transitions often detected as somatic mutations in nodular thyroid tissue. However, the absence of increased SMR would argue for more efficient DNA repair in response to iodine restriction.
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112
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De Souza RA, Maier J. Capacitance of single crystal and low-angle tilt bicrystals of Fe-doped SrTiO3. Faraday Discuss 2007; 134:235-45; discussion 315-29, 415-9. [PMID: 17326571 DOI: 10.1039/b602914k] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We used a.c. impedance spectroscopy to study the capacitance of single crystal and bicrystal Fe-doped SrTiO3. Measurements performed on a single crystal sample indicate unequivocally that the bulk dielectric permittivity is dependent on defect concentration. Three symmetrical [001] tilt bicrystals with misorientation angles theta = 2.3, 5.4 and 7.8 degrees were examined. The area specific capacitances obtained for the 5.4 and 7.8 degrees boundaries are consistent with values predicted from a one-dimensional double-Schottky-barrier model. For the 2.3 degrees boundary, more complex behaviour was observed. This is attributed to the electrical non-uniformity of the interface becoming significant at large dislocation separation. The effects of a d.c. bias on the impedance of the bicrystals was also investigated.
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113
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Maier J. Mass storage in space charge regions of nano-sized systems : (Nano-ionics. Part V). Faraday Discuss 2007; 134:51-66; discussion 103-18, 415-9. [PMID: 17326562 DOI: 10.1039/b603559k] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The consideration of space charge effects at interfaces results in the prediction of considerable storage anomalies in two-phase materials. They are particularly expected in nano-sized systems building a bridge between chemical and electrostatic storage. These effects are systematically treated in the model of an abrupt planar contact. Several examples of fundamental and/or practical interest are analysed in greater detail.
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114
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Steininger H, Schuster M, Kreuer KD, Kaltbeitzel A, Bingöl B, Meyer WH, Schauff S, Brunklaus G, Maier J, Spiess HW. Intermediate temperature proton conductors for PEM fuel cells based on phosphonic acid as protogenic group: A progress report. Phys Chem Chem Phys 2007; 9:1764-73. [PMID: 17415487 DOI: 10.1039/b618686f] [Citation(s) in RCA: 180] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The melting behaviour and transport properties of straight chain alkanes mono- and difunctionalized with phosphonic acid groups have been investigated as a function of their length. The increase of melting temperature and decrease of proton conductivity with increasing chain length is suggested to be the consequence of an increasing ordering of the alkane segments which constrains the free aggregation of the phosphonic acid groups. However, the proton mobility is reduced to a greater extent than the proton diffusion coefficient indicating an increasing cooperativity of proton transport with increasing length of the alkane segment. The results clearly indicate that the "spacer concept", which had been proven successful in the optimization of the proton conductivity of heterocycle based systems, fails in the case of phosphonic acid functionalized polymers. Instead, a very high concentration of phosphonic acid functional groups forming "bulky" hydrogen bonded aggregates is suggested to be essential for obtaining very high proton conductivity. Aggregation is also suggested to reduce condensation reactions generally observed in phosphonic acid containing systems. On the basis of this understanding, the proton conductivities of poly(vinyl phosphonic acid) and poly(meta-phenylene phosphonic acid) are discussed. Though both polymers exhibit a substantial concentration of phosphonic acid groups, aggregation seems to be constrained to such an extent that intrinsic proton conductivity is limited to values below sigma = 10(-3) S cm(-1) at T = 150 degrees C. The results suggest that different immobilization concepts have to be developed in order to minimize the conductivity reduction compared to the very high intrinsic proton conductivity of neat phosphonic acid under quasi dry conditions. In the presence of high water activities, however, (as usually present in PEM fuel cells) the very high ion exchange capacities (IEC) possible for phosphonic acid functionalized ionomers (IEC >10 meq g(-1)) may allow for high proton conductivities in the intermediate temperature range (T approximately 120 -160 degrees C).
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115
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Merkle R, Vracar M, Kuzmin A, Purans J, Kotomin EA, Maier J. SrFexTi1−xO3−δ: studies of local structure and (electro)chemical oxygen incorporation kinetics. Z Anorg Allg Chem 2006. [DOI: 10.1002/zaac.200670063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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116
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Hennig C, Bluhm T, Heimann P, Kroiss H, Kühner G, Kühntopf H, Maier J, Zilker M. Using the network as bus system for long discharge data acquisition and data processing. FUSION ENGINEERING AND DESIGN 2006. [DOI: 10.1016/j.fusengdes.2006.04.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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117
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Kühntopf H, Kroiss H, Bluhm T, Heimann P, Hennig C, Kühner G, Maier J, Zilker M. Specialized editor for processing objects in a database to prepare discharges for WENDELSTEIN 7-X. FUSION ENGINEERING AND DESIGN 2006. [DOI: 10.1016/j.fusengdes.2006.04.048] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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118
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Maier J, van Steeg H, van Oostrom C, Karger S, Paschke R, Krohn K. Deoxyribonucleic acid damage and spontaneous mutagenesis in the thyroid gland of rats and mice. Endocrinology 2006; 147:3391-7. [PMID: 16627585 DOI: 10.1210/en.2005-1669] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Thyroid tumors are a frequent finding not only in iodine-deficient regions. They are predominantly characterized by somatic genetic changes (e.g. point mutations or rearrangements). Because slow thyroid proliferation is a apparent contradiction to a high frequency of tumor initiation, we characterized mutational events in thyroid. First we studied the frequency of certain base exchanges in somatic TSH receptor (TSHR) mutations and determined the spontaneous mutation rate in thyroid and liver. Then we applied different protocols of the comet assay to quantify genomic DNA damage and conducted immunohistochemistry for 8-oxoguanine as a molecular marker for oxidative stress. Among 184 somatic mutations of the human TSHR found in thyroid tumors, C-->T transitions had a unexpectedly high frequency (>32%). The mutation rate in thyroid is 8-10 times higher than in other organs. The comet assay detected increased levels of oxidized pyrimidine (2- to 3-fold) and purine (2- to 4-fold) in thyroid, compared with liver and lung, and a 1.6-fold increase of oxidized purine, compared with spleen. Immunohistochemistry revealed high levels of 8-oxoguanine in thyroid epithelial cells. We have shown a strikingly high mutation rate in the thyroid. Furthermore, results of the comet assay as well as immunohistochemistry suggest that oxidative DNA modifications are a likely cause of the higher mutation rate. It is possible that free radicals resulting from reactive oxygen species in the thyroid generate mutations more frequently. This is also supported by the spectrum of somatic mutations in the TSHR because more frequent base changes could stem from oxidized base adducts that we detected in the comet assay and with immunohistochemistry.
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119
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Schröder A, Fleig J, Gryaznov D, Maier J, Sitte W. Quantitative Model of Electrochemical Ostwald Ripening and Its Application to the Time-Dependent Electrode Potential of Nanocrystalline Metals. J Phys Chem B 2006; 110:12274-80. [PMID: 16800548 DOI: 10.1021/jp060788t] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The contact of a metastable nanocrystalline metal ensemble with a metal ion electrolyte leads to an electrochemical Ostwald ripening. The kinetics is modeled on the level of irreversible thermodynamics for the case that the rate is controlled by the electrode/electrolyte transfer resistance. In particular, the kinetic behavior of medium-sized particles and the time dependence of the electromotive force is investigated. Even though it is expressed in electrochemical terms (mixed potential), the modeling is also applicable to chemical Ostwald ripening as long as it is interfacially controlled. Under these conditions, the kinetics exhibits, even though not self-accelerating, strong similarities to selection dynamics, with the competition stemming from the cannibalistic nature of the process.
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120
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Maier J, Paschke R, Krohn K. DNA modification and thyroid mutagenesis. Exp Clin Endocrinol Diabetes 2006. [DOI: 10.1055/s-2006-932910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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121
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Jamnik J, Kalnin JR, Kotomin EA, Maier J. Generalised Maxwell-Garnett equation: application to electrical and chemical transport. Phys Chem Chem Phys 2006; 8:1310-4. [PMID: 16633611 DOI: 10.1039/b514448p] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this paper we discuss the implementation of different equilibrium concentrations in each of the phases into the Maxwell-Garnett effective medium formula for diffusion in heterogeneous media. We put the derivation given by Kalnin et al., J. Phys. Chem. Solids, 2002, 63, 449, on safer grounds and extend it to non-dilute carrier concentrations. The relation to Maxwell's mixing rule is also elaborated. It is shown that the formula can not only successfully be applied to conductivity problems but also to describe steady state chemical diffusion in heterogeneous media such as polycrystalline samples. The comparison with the brick layer model corroborates these points but also shows that-in the case of heterogeneous media-one has to be cautious in applying steady state results to transient kinetics.
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122
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Kossoy A, Feldman Y, Wachtel E, Gartsman K, Lubomirsky I, Fleig J, Maier J. On the origin of the lattice constant anomaly in nanocrystalline ceria. Phys Chem Chem Phys 2006; 8:1111-5. [PMID: 16633592 DOI: 10.1039/b513764k] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The lattice parameter of nanocrystalline ceria films prepared by sputtering was monitored as a function of annealing temperature. Within the temperature range of 150-420 degrees C, an equilibrium with atmospheric oxygen is established within a few hours, whereas grain growth does not occur. On the basis of the experimental results and analysis of literature data, we present a model that posits the formation of a non-uniform grain structure with stoichiometric interiors and oxygen deficient boundaries. This model, based on defect thermodynamics, correctly describes the dependence of the lattice parameter of nanocrystalline ceria on annealing temperature and grain size and can be extended to other materials as well.
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123
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Maier J. Nanoionics: ion transport and electrochemical storage in confined systems. NATURE MATERIALS 2005; 4:805-15. [PMID: 16379070 DOI: 10.1038/nmat1513] [Citation(s) in RCA: 653] [Impact Index Per Article: 34.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The past two decades have shown that the exploration of properties on the nanoscale can lead to substantially new insights regarding fundamental issues, but also to novel technological perspectives. Simultaneously it became so fashionable to decorate activities with the prefix 'nano' that it has become devalued through overuse. Regardless of fashion and prejudice, this article shows that the crystallizing field of 'nanoionics' bears the conceptual and technological potential that justifies comparison with the well-acknowledged area of nanoelectronics. Demonstrating this potential implies both emphasizing the indispensability of electrochemical devices that rely on ion transport and complement the world of electronics, and working out the drastic impact of interfaces and size effects on mass transfer, transport and storage. The benefits for technology are expected to lie essentially in the field of room-temperature devices, and in particular in artificial self-sustaining structures to which both nanoelectronics and nanoionics might contribute synergistically.
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Maier J, Melzl H, Reischl U, Drubel I, Witte W, Lehn N, Linde H. Panton–Valentine leukocidin-positive methicillin-resistant Staphylococcus aureus in Germany associated with travel or foreign family origin. Eur J Clin Microbiol Infect Dis 2005; 24:637-9. [PMID: 16167136 DOI: 10.1007/s10096-005-0008-8] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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125
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Dyhrfjeld-Johnsen J, Maier J, Schubert D, Staiger J, Luhmann HJ, Stephan KE, Kötter R. CoCoDat: a database system for organizing and selecting quantitative data on single neurons and neuronal microcircuitry. J Neurosci Methods 2005; 141:291-308. [PMID: 15661312 DOI: 10.1016/j.jneumeth.2004.07.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2004] [Revised: 06/27/2004] [Accepted: 07/09/2004] [Indexed: 11/26/2022]
Abstract
We present a novel database system for organizing and selecting quantitative experimental data on single neurons and neuronal microcircuitry that has proven useful for reference-keeping, experimental planning and computational modelling. Building on our previous experience with large neuroscientific databases, the system takes into account the diversity and method-dependence of single cell and microcircuitry data and provides tools for entering and retrieving published data without a priori interpretation or summarizing. Data representation is based on the framework suggested by biophysical theory and enables flexible combinations of data on membrane conductances, ionic and synaptic currents, morphology, connectivity and firing patterns. Innovative tools have been implemented for data retrieval with optional relaxation of search criteria along the conceptual dimensions of brain region, cortical layer, cell type and subcellular compartment. The relaxation procedures help to overcome the traditional trade-off between exact, non-interpreted data representation in the original nomenclature and convenient data retrieval. We demonstrate the use of these tools for the construction, tuning and validation of a multicompartmental model of a layer V pyramidal cell from the rat barrel cortex. CoCoDat is freely available at . Its application is scalable from offline use by individual researchers via local laboratory networks to a federation of distributed web sites in platform-independent XML format using Axiope tools.
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