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Al-Hada M, Peters S, Gregoratti L, Amati M, Sezen H, Parisse P, Selve S, Niermann T, Berger D, Neeb M, Eberhardt W. Nanoparticle formation of deposited Ag -clusters on free-standing graphene. Surface Science 2017. [DOI: 10.1016/j.susc.2017.06.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Peredkov S, Peters S, Al-Hada M, Erko A, Neeb M, Eberhardt W. Structural investigation of supported Cun clusters under vacuum and ambient air conditions using EXAFS spectroscopy. Catal Sci Technol 2016. [DOI: 10.1039/c6cy00436a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Structural analysis of deposited nanoclusters using extended X-ray absorption fine structure (EXAFS) spectroscopy.
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Affiliation(s)
- S. Peredkov
- IOAP
- Technische Universität Berlin
- 10623 Berlin
- Germany
| | - S. Peters
- IOAP
- Technische Universität Berlin
- 10623 Berlin
- Germany
| | - M. Al-Hada
- Department of Physics
- College of Education and Linguistics
- University of Amran
- Yemen
| | - A. Erko
- Helmholtz-Zentrum Berlin
- 12489 Berlin
- Germany
| | - M. Neeb
- Helmholtz-Zentrum Berlin
- 12489 Berlin
- Germany
| | - W. Eberhardt
- IOAP
- Technische Universität Berlin
- 10623 Berlin
- Germany
- DESY
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Peters S, Peredkov S, Neeb M, Eberhardt W, Al-Hada M. Size-dependent Auger spectra and two-hole Coulomb interaction of small supported Cu-clusters. Phys Chem Chem Phys 2013. [PMID: 23666087 DOI: 10.1016/j.susc.2012.09.024] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/30/2023]
Abstract
Auger (L3M4,5M4,5) and X-ray photoionization spectra (2p, 3d) of mass-selected CuN-clusters supported by a thin natural silica layer are presented in the size range N = 8-55 atoms per cluster. The Auger spectra of all clusters are shifted to a lower kinetic energy with respect to the spectrum of the bulk. Furthermore the Auger energy decreases systematically with decreasing cluster size. The binding energies of the 2p and 3d valence states are higher than the corresponding bulk values. Using the energy of the Auger main line, the corresponding core hole peak and the centroid of the self-convoluted 3d valence band the on-site Coulomb interaction energy Udd of the two-hole final state as a function of cluster size has been determined.
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Affiliation(s)
- S Peters
- Helmholtz-Zentrum Berlin, Wilhelm-Conrad-Röntgen-Campus Adlershof, Elektronenspeicherring BESSY II, Berlin, Germany
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Peters S, Peredkov S, Neeb M, Eberhardt W, Al-Hada M. Size-dependent Auger spectra and two-hole Coulomb interaction of small supported Cu-clusters. Phys Chem Chem Phys 2013; 15:9575-80. [DOI: 10.1039/c3cp00109a] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Peredkov S, Neeb M, Eberhardt W, Meyer J, Tombers M, Kampschulte H, Niedner-Schatteburg G. Spin and orbital magnetic moments of free nanoparticles. Phys Rev Lett 2011; 107:233401. [PMID: 22182086 DOI: 10.1103/physrevlett.107.233401] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Indexed: 05/31/2023]
Abstract
The determination of spin and orbital magnetic moments from the free atom to the bulk phase is an intriguing challenge for nanoscience, in particular, since most magnetic recording materials are based on nanostructures. We present temperature-dependent x-ray magnetic circular dichroism measurements of free Co clusters (N=8-22) from which the intrinsic spin and orbital magnetic moments of noninteracting magnetic nanoparticles have been deduced. An exceptionally strong enhancement of the orbital moment is verified for free magnetic clusters which is 4-6 times larger than the bulk value. Our temperature-dependent measurements reveal that the spin orientation along the external magnetic field is nearly saturated at ~20 K and 7 T, while the orbital orientation is clearly not.
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Affiliation(s)
- S Peredkov
- Institut für Optik und Atomare Physik, Technische Universität Berlin, Hardenbergstrasse 36, 10623 Berlin, Germany
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Peters S, Peredkov S, Balkaya B, Ferretti N, Savci A, Vollmer A, Neeb M, Eberhardt W. Inner-shell photoionization spectroscopy on deposited metal clusters using soft x-ray synchrotron radiation: an experimental setup. Rev Sci Instrum 2009; 80:125106. [PMID: 20059169 DOI: 10.1063/1.3267193] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Exploration of mass-selected clusters by soft x-ray synchrotron radiation is well suited to receive element specific information on clusters in contact with a support and to systematically follow the evolution of size-dependent electronic and geometrical properties from the smallest clusters toward the bulk. Here we describe an experimental setup, which combines cluster synthesis, mass selection, soft landing, ultrahigh vacuum transfer, and photoionization experiments such as x-ray photoelectron spectroscopy, x-ray absorption, and Auger electron spectroscopy. First spectroscopic results and experimental conditions are briefly discussed for Cu(19) deposited onto the natural oxide layer of a Si-wafer surface.
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Affiliation(s)
- S Peters
- Helmholtz-Zentrum Berlin für Materialien und Energie, Wilhelm-Conrad-Röntgen-Campus Adlershof, Elektronenspeicherring BESSY II, Albert-Einstein Strasse 15, D-12489 Berlin, Germany
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Senz V, Fischer T, Oelssner P, Tiggesbäumker J, Stanzel J, Bostedt C, Thomas H, Schöffler M, Foucar L, Martins M, Neville J, Neeb M, Möller T, Wurth W, Rühl E, Dörner R, Schmidt-Böcking H, Eberhardt W, Ganteför G, Treusch R, Radcliffe P, Meiwes-Broer KH. Core-hole screening as a probe for a metal-to-nonmetal transition in lead clusters. Phys Rev Lett 2009; 102:138303. [PMID: 19392409 DOI: 10.1103/physrevlett.102.138303] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2008] [Indexed: 05/27/2023]
Abstract
Metal clusters serve as model systems to study basic problems of electronic correlation. Vacuum ultraviolet light from the free-electron laser FLASH ionizes 5d electrons from mass-separated negatively charged clusters, thus transiently leading to core-ionized neutral systems. Shielding of the core hole affects the electron binding energy. From the strong deviation from expectations of the metallic droplet and jellium models we conclude on reduced electronic shielding once the cluster size falls below about 20 atoms. This suggests a metal-to-nonmetal transition, in agreement with previous local density approximation calculations.
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Affiliation(s)
- V Senz
- Institut für Physik, Universität Rostock, 18051 Rostock, Germany.
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Moreh E, Meiner Z, Neeb M, Hiller N, Schwartz I. Spinal decompression sickness presenting as partial brown-sequard syndrome and treated with robotic-assisted body-weight support treadmill training. J Rehabil Med 2009; 41:88-9. [DOI: 10.2340/16501977-0279] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Mitzner R, Siemer B, Neeb M, Noll T, Siewert F, Roling S, Rutkowski M, Sorokin AA, Richter M, Juranic P, Tiedtke K, Feldhaus J, Eberhardt W, Zacharias H. Spatio-temporal coherence of free electron laser pulses in the soft x-ray regime. Opt Express 2008; 16:19909-19919. [PMID: 19030078 DOI: 10.1364/oe.16.019909] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The temporal coherence properties of soft x-ray free electron laser pulses at FLASH are measured at 23.9 nm by interfering two time-delayed partial beams directly on a CCD camera. The partial beams are obtained by wave front beam splitting in an autocorrelator operating at photon energies from h nu = 30 to 200 eV. At zero delay a visibility of (0.63+/- 0.04) is measured. The delay of one partial beam reveals a coherence time of 6 fs at 23.9 nm. The visibility further displays a non-monotonic decay, which can be rationalized by the presence of multiple pulse structure.
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Affiliation(s)
- R Mitzner
- Physikalisches Institut, Westfälische Wilhelms-Universität, 48149 Münster, Germany
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Neeb M, Kunz P, Karg A, Kreitner KF, Thelen M, Schreiber WG. Optimierung von MRT-Sequenzen für die Absolutquantifizierung der Lungenperfusion. ROFO-FORTSCHR RONTG 2005. [DOI: 10.1055/s-2005-863994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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11
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Nyska M, Shabat S, Simkin A, Neeb M, Matan Y, Mann G. Dynamic force distribution during level walking under the feet of patients with chronic ankle instability. Br J Sports Med 2004; 37:495-7. [PMID: 14665586 PMCID: PMC1724712 DOI: 10.1136/bjsm.37.6.495] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
OBJECTIVES To examine changes in the pattern of force transfer between the foot and the floor associated with chronically sprained ankles by measuring the peak forces and their timing under several regions of the feet during level walking. METHODS Twelve young male subjects (mean (SD) age 21 (2) years) with recurrent ankle sprains were studied. Seven of them had unilateral and bilateral chronic instability and laxity, and five had bilateral instability. Twelve healthy men (without orthopaedic or medical disease) served as a control group. Subjects walked at their own pace along a 7 m walkway, which included a Mini-EMED pressure distribution measuring system. The variables measured were relative peak force (fraction of body weight) and relative timing (fraction of stance time). These variables were measured under six regions of interest in each foot print: heel, midfoot, medial, central, and lateral forefoot, and toes. RESULTS (a) A significant delay to the time of peak force under the central and lateral forefoot and toes in subjects with chronic ankle instability. (b) A significant decrease in the relative forces under the heel and toes and an increase in the relative forces under the midfoot and lateral forefoot in subjects with chronic ankle instability. (c) In the patients with unilateral instability, there were no significant differences in any of the variables between the injured and non-injured foot. CONCLUSIONS In patients with chronic ankle instability, there is a slowing down of weight transfer from heel strike to toe off, a reduced impact at the beginning and end of the stance phase, and a lateral shift of body weight.
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Affiliation(s)
- M Nyska
- Department of Orthopaedic Surgery, Foot and Ankle Service, Sapir Medical Center, Kfar-Saba and Tel-Aviv Sackler Medical Faculty, Israel
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Lüttgens G, Pontius N, Bechthold PS, Neeb M, Eberhardt W. Photon-induced thermal desorption of CO from small metal-carbonyl clusters. Phys Rev Lett 2002; 88:076102. [PMID: 11863916 DOI: 10.1103/physrevlett.88.076102] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2001] [Indexed: 05/23/2023]
Abstract
Thermal CO desorption from photoexcited free metal-carbonyl clusters has been resolved in real time using two-color pump-probe photoelectron spectroscopy. Sequential energy dissipation steps between the initial photoexcitation and the final desorption event, e.g., electron relaxation and thermalization, have been resolved for Au2(CO)(-) and Pt2(CO)5-. The desorption rates for the two clusters differ considerably due to the different numbers of vibrational degrees of freedom. The unimolecular CO-desorption thresholds of Au2(CO)(-) and Pt2(CO)5- have been approximated by means of a statistical Rice-Ramsperger-Kassel calculation using the experimentally derived desorption rate constants.
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Affiliation(s)
- G Lüttgens
- Institut für Festkörperforschung, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
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Brem R, Certa U, Neeb M, Nair AP, Moroni C. Global analysis of differential gene expression after transformation with the v-H-ras oncogene in a murine tumor model. Oncogene 2001; 20:2854-8. [PMID: 11420697 DOI: 10.1038/sj.onc.1204403] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2000] [Revised: 02/14/2001] [Accepted: 02/19/2001] [Indexed: 11/09/2022]
Abstract
Mouse PB-3c mast cells stably transfected with the v-H-ras oncogene induce tumor formation in vivo when implanted into mice. Such tumor cells are characterized by an autocrine IL-3 loop. DNA microarrays allow simultaneous transcript imaging of several thousand genes and the technique was applied in this tumor model to analyse gene expression following malignant transformation. Using three independent tumor lines derived from the same precursor the expression of about 400 out of 11 000 genes was modulated in each tumor. A subset of only 75 genes (0.68%) is shared and up- or downregulated in all three lines. A significant portion of this gene pool possesses functions related to tumorigenesis such as cell adhesion, signaling or transcriptional regulation. Apart from a number of expressed sequence tags (EST's) we find downregulation of four interferon-inducible genes in the tumor lines. Finally, when we extrapolate our data to the complete mouse genome, we estimate that about 500 genes are differentially expressed in tumor cells compared to the precursor cell PB-3c.
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Affiliation(s)
- R Brem
- Department of Roche Genetics, F. Hoffmann La-Roche Ltd., CH-4070 Basel, Switzerland
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Lüttgens G, Pontius N, Friedrich C, Klingeler R, Bechthold PS, Neeb M, Eberhardt W. Chemisorption of benzene on metal dimer anions: A study by photoelectron detachment spectroscopy. J Chem Phys 2001. [DOI: 10.1063/1.1366333] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Pontius N, Lüttgens G, Bechthold PS, Neeb M, Eberhardt W. Size-dependent hot-electron dynamics in small Pd[sub n][sup −]-clusters. J Chem Phys 2001. [DOI: 10.1063/1.1415449] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Rogge L, Bianchi E, Biffi M, Bono E, Chang SY, Alexander H, Santini C, Ferrari G, Sinigaglia L, Seiler M, Neeb M, Mous J, Sinigaglia F, Certa U. Transcript imaging of the development of human T helper cells using oligonucleotide arrays. Nat Genet 2000; 25:96-101. [PMID: 10802665 DOI: 10.1038/75671] [Citation(s) in RCA: 189] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Many pathological processes, including those causing allergies and autoimmune diseases, are associated with the presence of specialized subsets of T helper cells at the site of inflammation. Understanding the genetic program that controls the functional properties of T helper type 1 (Th1) versus T helper type 2 (Th2) cells may provide insight into the pathophysiology of inflammatory diseases. We compared the gene-expression profiles of human Th1 and Th2 cells using high-density oligonucleotide arrays with the capacity to display transcript levels of 6,000 human genes. Here we analyse the data sets derived from five independent experiments using statistical algorithms. This approach resulted in the identification of 215 differentially expressed genes, encoding proteins involved in transcriptional regulation, apoptosis, proteolysis, and cell adhesion and migration. A subset of these genes was further upregulated by exposure of differentiated Th1 cells to interleukin-12 (IL-12), as confirmed by kinetic PCR analysis, indicating that IL-12 modulates the effector functions of Th1 cells in the absence of antigenic stimulation. Functional assays and in vivo expression of selected genes have validated the biological relevance of our study. Our results provide new insight into the transcriptional program controlling the functional diversity of subsets of T helper cells.
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Affiliation(s)
- L Rogge
- Roche Milano Ricerche, Milano, Italy.
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Neeb M, Kivimäki A, Kempgens B, Köppe H, Maier K, Bradshaw A, Kosugi N. Partial electron yield spectrum of N2: doubly excited states at the K-shell threshold. Chem Phys Lett 2000. [DOI: 10.1016/s0009-2614(00)00229-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Pontius N, Bechthold PS, Neeb M, Eberhardt W. Ultrafast hot-electron dynamics observed in Pt( -)(3) using time-resolved photoelectron spectroscopy. Phys Rev Lett 2000; 84:1132-1135. [PMID: 11017461 DOI: 10.1103/physrevlett.84.1132] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/1999] [Indexed: 05/23/2023]
Abstract
Time-resolved two-photon photoelectron spectra have been measured for free Pt( -)(3) using femtosecond pulses of 1.5 eV photon energy in a pump-probe configuration. The time-dependent photoelectron distribution reveals a lifetime of optically excited states of less than 70 fs. Such an unexpected fast electron relaxation in Pt( -)(3) suggests the existence of inelastic electron-electron scattering processes in a triatomic cluster which result in a lifetime similar to those of bulk metals.
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Affiliation(s)
- N Pontius
- Institut fur Festkorperforschung, Forschungszentrum Julich GmbH, D-52425 Julich, Germany
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21
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Kempgens B, Kivimäki A, Köppe HM, Neeb M, Bradshaw AM, Feldhaus J. One-electron versus multielectron effects in the near-threshold C 1s photoionization of acetylene. J Chem Phys 1997. [DOI: 10.1063/1.474796] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Piancastelli MN, Neeb M, Kivimäki A, Kempgens B, Köppe HM, Maier K, Bradshaw AM. Variation of Cross-Section Enhancement in Decay Spectra of CO under Resonant Raman Conditions. Phys Rev Lett 1996; 77:4302-4305. [PMID: 10062504 DOI: 10.1103/physrevlett.77.4302] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Kivimäki A, Neeb M, Kempgens B, Köppe HM, Bradshaw AM. Angle-resolved Auger spectrum of the N2 molecule. Phys Rev A 1996; 54:2137-2141. [PMID: 9913704 DOI: 10.1103/physreva.54.2137] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/11/2023]
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Rubensson JE, Neeb M, Bringer A, Biermann M, Eberhardt W. Electronic state-lifetime interference observed at Ne K inter-resonance excitation. Chem Phys Lett 1996. [DOI: 10.1016/0009-2614(96)00596-9] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Köppe HM, Itchkawitz BS, Kilcoyne AL, Feldhaus J, Kempgens B, Kivimäki A, Neeb M, Bradshaw AM. High-resolution C 1s photoelectron spectra of methane. Phys Rev A 1996; 53:4120-4126. [PMID: 9913376 DOI: 10.1103/physreva.53.4120] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Rubensson J, Lüning J, Neeb M, Küpper B, Eisebitt S, Eberhardt W. Photoelectron soft x-ray fluorescence coincidence spectroscopy on free molecules. Phys Rev Lett 1996; 76:3919-3922. [PMID: 10061146 DOI: 10.1103/physrevlett.76.3919] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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27
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Neeb M, Kivimäki A, Kempgens B, Köppe HM, Feldhaus J, Bradshaw AM. Core hole double-excitation and atomiclike Auger decay in N2. Phys Rev Lett 1996; 76:2250-2253. [PMID: 10060650 DOI: 10.1103/physrevlett.76.2250] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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28
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Neeb M, Kivimäki A, Kempgens B, Köppe HM, Bradshaw AM, Feldhaus J. Conjugate shake-up-enhanced Auger transitions in N2. Phys Rev A 1995; 52:1224-1228. [PMID: 9912362 DOI: 10.1103/physreva.52.1224] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Neeb M, Rubensson J, Biermann M, Eberhardt W. Determination of the exchange splitting of the shape resonance of O2 using the core hole decay spectrum as a "fingerprint.". Phys Rev Lett 1993; 71:3091-3094. [PMID: 10054855 DOI: 10.1103/physrevlett.71.3091] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Krummacher S, Biermann M, Neeb M, Liebsch A, Eberhardt W. Close similarity of the electronic structure and electron correlation in gas-phase and solid C60. Phys Rev B Condens Matter 1993; 48:8424-8429. [PMID: 10007039 DOI: 10.1103/physrevb.48.8424] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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31
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Rubensson J, Neeb M, Biermann M, Xu Z, Eberhardt W. Electronic decay of vibrationally selected core excited states in molecular N2. J Chem Phys 1993. [DOI: 10.1063/1.465332] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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32
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Haas-Lauterbach S, Scharf M, Sprunkel B, Neeb M, Koller KP, Engels JW. High yield fermentation and purification of Tendamistat disulphide analogues secreted by Streptomyces lividans. Appl Microbiol Biotechnol 1993; 38:719-27. [PMID: 7763532 DOI: 10.1007/bf00167134] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
In our studies of structure-function correlation of polypeptides we used Tendamistat (TM), an alpha-amylase-inhibitor of Streptomyces tendae, as a model to investigate the influence of different mutants on the expression and secretion of the protein. In addition, we examined the influence of replacing the two disulphide-bridges that stabilize the two-loop structure of the whole protein. The single mutants C27S, C27T, C45A, the double mutants C11A/C27A, C11A/C27S, C11A/C27T, C11A/C27L, C45/C73A and the fourfold mutant C11A/C27A/C45A/C73A were prepared. The mutated TM gene was expressed in S. lividans TK 24, which secretes the active form of the inhibitor into the culture medium. Compared with the wild-type, the double-mutated TM derivatives show an increase in secreted protein by a factor of two to ten. In contrast, the single-mutated inhibitor analogues show the reverse effect. In order to examine the influence of temperature and culture media on the production of protein derivative we used the most unstable C11A analogue. Our expression studies at 10, 19, 28 and 37 degrees C established 19 degrees C as the optimal temperature for production of the protein derivatives. The correlation between the stability and secretion of TM is discussed in the context of our knowledge of protein translocation in bacteria. Based on these experiments we optimized the fermentation parameters, isolated TM analogous on a large scale, and verified them.
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Affiliation(s)
- S Haas-Lauterbach
- Institut für Organische Chemie, Johann Wolfgang Goethe Universität, Frankfurt am Main, Federal Republic of Germany
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Neeb M, Kunz U, Koepsell H. Identification of D-glucose-binding polypeptides which are components of the renal Na+-D-glucose cotransporter. J Biol Chem 1987; 262:10718-27. [PMID: 3611086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
D-Glucose-binding polypeptides in the Na+-D-glucose cotransporter from pig renal cortex were identified by affinity labeling with two D-glucose analogs, 10-N-(N-[4-azido-2-nitrophenyl]-beta-alanyl)amino-1-decyl-beta-D- glucopyranoside (NapADG) and 10-N-(bromoacetyl)amino-1-decyl-beta-D-glucopyranoside (BADG). During short-term incubation in the dark, NapADG and BADG are reversible inhibitors of Na+ gradient-dependent D-glucose uptake and Na+-dependent phlorizin binding with Ki values of about 40 and 400 microM, respectively. Irreversible inhibition of Na+-dependent phlorizin binding, which was prevented by D-glucose or phlorizin, was measured after a 1-h incubation with BADG. Both NapADG and BADG selectively labeled polypeptides with apparent molecular weights of 82,000, 75,000, 64,000, and 47,000. Since labeling of the Mr 82,000 and 75,000 polypeptides by both analogs was partially dependent on the presence of Na+ and was partially protected by D-glucose or phlorizin but not by L-glucose or D-mannose, these polypeptides are thought to be components of the renal Na+-D-glucose cotransporter which contain D-glucose-binding sites. For the Mr 64,000 and 47,000 polypeptides, Na+ dependence and D-glucose protection were not constantly observed. However, also, these polypeptides are thought to be components or proteolytic splitting products of the Na+-D-glucose cotransporter since we observed that three monoclonal antibodies showed cross-reaction with the BADG-labeled Mr 82,000, 64,000, and 47,000 polypeptides (K. Korn, A. Raszeja-Specht, S. Bernotat-Danielowski, and H. Koepsell, manuscript in preparation). When the BADG-labeled Mr 82,000 and 75,000 polypeptides were analyzed after two-dimensional separation by isoelectric focusing and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, three-labeled, D-glucose-protectable polypeptides with the respective molecular weights and isoelectric points of 82,000 and 5.6, 75,000 and 5.4, and 75,000 and 6.9 were distinguished. The data indicate that renal brush-border membranes contain several polypeptides which are components of the Na+-D-glucose cotransporter and contain D-glucose-binding sites.
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Neeb M, Fasold H, Koepsell H. Identification of the D-glucose binding polypeptide of the renal Na+-D-glucose cotransporter with a covalently binding D-glucose analog. FEBS Lett 1985; 182:139-44. [PMID: 3838282 DOI: 10.1016/0014-5793(85)81171-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The covalently binding D-glucose analog 10-N-(bromoacetyl)amino-1-decyl-beta-D-glucopyranoside (BADG) was synthesised and shown to be a high-affinity inhibitor of the renal Na+-D-glucose contransporter. From renal brush-border membranes a protein fraction was isolated, in which the concentration of Na+-dependent phlorizin binding sites per mg protein was enriched 7-fold. In labeling experiments with this protein fraction a polypeptide of Mr approximately 79000 was identified as containing the D-glucose binding site of the renal Na+-D-glucose cotransporter.
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Ficher M, Zuckerman M, Fishkin RE, Goldman A, Neeb M, Fink PJ, Cohen SN, Jacobs JA, Weisberg M. Do endocrines play an etiological role in diabetic and nondiabetic sexual dysfunctions? J Androl 1984; 5:8-16. [PMID: 6423596 DOI: 10.1002/j.1939-4640.1984.tb00771.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Sexually dysfunctional diabetic and nondiabetic males were compared with a group of normal controls using different endocrinological, psychophysiological, and psychological parameters. One hundred male subjects participated in this study: 47 diabetics with sexual dysfunction (DD), 31 nondiabetics with sexual dysfunction (NDD), and 22 normal controls (C). They were evaluated by an internist (physical examination and medical history), a psychologist (psychological and sexual functioning tests), a psychiatrist (psychiatric history and mental status examination), a urologist (genitourinary physical examination), and an endocrine biochemist (evaluation of endocrine factors). Additionally, subjects were evaluated for nocturnal penile tumescence (NPT) during three nights in the sleep laboratory to obtain a differential diagnosis of impotence, that is, psychogenic vs. organic. Both sexually dysfunctional groups showed significant differences on several measures in the psychological and psychophysiological evaluations. There were also significant differences between these two groups and the control group. Plasma levels of total testosterone and serum levels of prolactin, luteinizing hormone (LH) and follicle-stimulating hormone (FSH) showed no significant differences among the three groups, but there were some significant correlations between the endocrine and psychological measures. No significant correlations were found between the endocrine and psychophysiological measures.
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Ficher IV, Zuckerman M, Neeb M. Marital compatibility in sensation seeking trait as a factor in marital adjustment. J Sex Marital Ther 1981; 7:60-69. [PMID: 7345150 DOI: 10.1080/00926238108403441] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
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Abstract
A sample of 2,115 persons responded to an article in a popular magazine by taking the Sensation Seeking Scale (SSS) and supplying personal information by mail, including data about past treatment, hospitalization, and diagnosis of psychiatric disorders. Subjects falling into certain diagnostic categories were closely matched with controls from the same sample who reported no history, treatment, or diagnosis of disorder. SSS scores were not related to general psychopathology, unipolar depression, schizophrenia, or neurosis, but were found to be elevated in persons reporting a history of manic-depressive or sociopathic spectrum (including alcoholism and drug abuse) disorder.
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