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  • 1
    Digitale Medien
    Digitale Medien
    Shattering of SiMe3+ during surface-induced dissociation (1998)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 109 (1998), S. 10976-10983 
    Details
    ISSN: 1089-7690
    Quelle: AIP Digital Archive
    Thema: Physik , Chemie und Pharmazie
    Notizen: We provide experimental evidence that upon hyperthermal impact of Si(CD3)3+ ions with an organic surface, a portion of the ions undergo dissociation while still in contact with the surface. We use a tandem configuration of quadrupole mass spectrometers along with an energy analyzer to measure the kinetic energy distributions of the fragments that form as a result of the surface scattering of 25 eV Si(CD3)3+. These distributions are different for scattering from a clean Au(111) surface versus scattering from an organic surface composed of a self-assembled monolayer of hexanethiolate on Au(111). Parent and fragment ions recoil from the clean Au(111) surface with the same velocity, as is expected for fragmentation away from the surface. However, the same scattering products recoil from the organic surface with different velocities but similar energies, suggesting that the fragmentation dynamics are modified by surface interactions. We perform molecular dynamics simulations which predict residence times of ∼210 fs at the organic surface and ∼20 fs at the Au surface. The simulations also predict that 13% and 31% of the ions fragment within 1.1 ps of surface impact at the organic and Au surfaces, respectively. Thus, the experimental observation of dissociation at only the organic surface results from its longer ion-surface interaction time. The fragmentation time scale predicted by Rice–Ramsperger-Kassel–Marcus calculations is yet longer, suggesting that at least a portion of the surface-induced dissociation of Si(CD3)3+ may occur via a nonstatistical mechanism. Our interpretation draws heavily from an analogous "shattering" mechanism previously proposed for cluster-surface scattering [E. Hendell, U. Even, T. Raz, and R. D. Levine, Phys. Rev. Lett. 75, 2670 (1995)]. © 1998 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.477737
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  • 2
    Digitale Medien
    Digitale Medien
    Energy transfer and surface-induced dissociation for SiMe3+ scattering off clean and adsorbate covered metals (1997)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 106 (1997), S. 10329-10336 
    Details
    ISSN: 1089-7690
    Quelle: AIP Digital Archive
    Thema: Physik , Chemie und Pharmazie
    Notizen: We scatter 10–70 eV SiMe3+ from clean Au(111), a hexanethiolate self-assembled monolayer on Au(111) (C6), and a NiO(111) layer grown on top of Ni(111). We examine both the scattered ion fragmentation patterns and the kinetic energy distribution spectra (KEDS) as a function of the incident ion energy E. Surface infrared and KEDS data indicate that we have prepared a saturated monolayer of hexanethiolate (C6) on Au(111) where the C6 carbon backbone is predominantly upright on the surface. C6 monolayers with a mixture of prone and upright C6 can also be prepared, but only the upright C6 monolayers are used for ion scattering experiments. The fragment ion distributions and the KEDS are then used to determine the channeling of the incident SiMe3+ion energy into the scattered ion internal energy Eint, and the scattered ion kinetic energy Escat. Overall, we find the order of Eint/E for SiMe3+ to be Au(111)(very-much-greater-than)NiO(111)〉C6. From the Escat values, we find that MiSe3+ scattering off C6 is highly inelastic while scattering off Au is much more elastic. We use this information to calculate the energy (Esurf) which is channeled into the surface as a result of the collision for C6 and Au(111). By comparing the KEDS for the parent and fragment ions, we determine the importance of unimolecular dissociation off the various surfaces. In the accompanying paper, we present a series of classical dynamics simulations to explain and supplement these experimental results. © 1997 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.474103
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  • 3
    Digitale Medien
    Digitale Medien
    Classical dynamics simulations of SiMe3+ ion–surface scattering (1997)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 106 (1997), S. 10337-10348 
    Details
    ISSN: 1089-7690
    Quelle: AIP Digital Archive
    Thema: Physik , Chemie und Pharmazie
    Notizen: This paper presents classical dynamics simulations of Si(CD3)3+scattering from a hexanethiolate self-assembled monolayer on Au(111) and from a clean Au(111) surface. Simulations are performed with a united atom model using purely repulsive scattering potentials. These simulations predict the partitioning of the incident ion kinetic energy into the scattered ion kinetic energy and the internal modes of both the surface and the ion. For the organic surface, the simulations predict energy transfer to surface, ion internal, and ion kinetic energies of 0.78, 0.11, and 0.12 of the collision energy. The corresponding transfer efficiencies of 0.12, 0.21, and 0.65 were calculated for the Au(111) surface. These computational results compare well with the experimental results on the same systems which are reported in the preceding paper. The simulations predict near specular scattering for both surfaces. They also demonstrate that the ion penetrates only the topmost two to three layers of Me atoms of the organic surface and that it spends up to 250 fs in contact with the surface. Finally, these calculations determine the dependence of energy transfer on the incident ion angle. © 1997 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.474069
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  • 4
    Digitale Medien
    Digitale Medien
    Boys’ Maladaptive Social Information Processing, Family Emotional Climate, and Pathways to Early Conduct Problems (2003)
    Oxford, UK : Blackwell Publishing Ltd.
    Social development 12 (2003), S. 0 
    Details
    ISSN: 1467-9507
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Psychologie
    Notizen: Maladaptive social information processing characterizes many children with behavioral adjustment difficulties. Yet, we know little about the antecedents of maladaptive social information processing. The present study examined the relations between early family risk and later maladaptive social information processing and conduct problems in a sample of 178 economically disadvantaged boys. Early childhood assessments of socioeconomic disadvantage (low SES, single parent status, low maternal education) and maternal depression predicted boys’ maladaptive response generation and conduct problems at age 10, accounting for 6% and 14% of the variances, respectively, but not hostile attribution bias. Maladaptive response generation also fit a model of significant partial mediation of the effects of socioeconomic disadvantage on conduct problems. Results suggest the importance of the family's emotional climate during children's early development for their later adjustment.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/1467-9507.00242
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  • 5
    Digitale Medien
    Digitale Medien
    Children’s Anger Attribution Bias: Relations to Family Environment and Social Adjustment (2000)
    Oxford, UK and Boston, USA : Blackwell Publishers Ltd.
    Social development 9 (2000), S. 0 
    Details
    ISSN: 1467-9507
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Psychologie
    Notizen: We examined the relations of caregiver depression and family instability to preschool children’s anger attribution bias and emotion attribution accuracy on a test of emotion situation knowledge. After controlling for age, gender, and verbal ability, caregiver depression and family instability predicted children’s anger attribution bias but not the overall accuracy of their emotion attributions. We also divided children into groups low and high on teacher reports of aggression and groups low and high on teacher reports of peer rejection and examined the anger attribution bias of these groups. For boys but not girls, greater anger attribution bias predicted higher levels of aggression. For all children, greater anger attribution bias predicted higher levels of peer rejection. Results suggest that the misattribution of anger to others may be an important component of some children’s early emotional and social difficulties.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/1467-9507.00126
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  • 6
    Digitale Medien
    Digitale Medien
    Acceleration of activation and inactivation by the β subunit of the skeletal muscle calcium channel (1991)
    [s.l.] : Nature Publishing Group
    Nature 352 (1991), S. 159-162 
    Details
    ISSN: 1476-4687
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Notizen: [Auszug] LCa.ll cells9 were cotransfected with various combinations of expression plasmids for a2, ft and y subunit cDNAs. Northern blot analyses of poly(A)+ RNA preparations from the various transfected cell lines (Fig. la, b) confirmed that the parental LtkT cells expressed no transcripts for the skeletal ...
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1038/352159a0
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  • 7
    Digitale Medien
    Digitale Medien
    A mechanosensory complex that mediates the endothelial cell response to fluid shear stress (2005)
    [s.l.] : Nature Publishing Group
    Nature 437 (2005), S. 426-431 
    Details
    ISSN: 1476-4687
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Notizen: [Auszug] Shear stress is a fundamental determinant of vascular homeostasis, regulating vascular remodelling, cardiac development and atherogenesis, but the mechanisms of transduction are poorly understood. Previous work showed that the conversion of integrins to a high-affinity state mediates a subset ...
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1038/nature03952
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  • 8
    Digitale Medien
    Digitale Medien
    Parental investment in temporally varying environments (1991)
    Springer
    Evolutionary ecology 5 (1991), S. 415-427 
    Details
    ISSN: 1573-8477
    Schlagwort(e): Parental investment ; egg size ; environmental uncertainty ; phenotypic variance ; life history variation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Using a model that allows the mean and variance of investment by parents in offspring to evolve in response to change in degree of temporal environmental variation, this paper shows that both parental investment parameters should increase with increases in temporal variation. If offspring receiving greater parental investment are viable over a broader range of environmental conditions, then increased temporal environmental variation can select for increases in parental investment. The variance in parental investment also may increase with increases in temporal variation, but there is a threshold level of temporal variation that must be exceeded before variance in parental investment is adaptive. Thus phenotypic variance in parental investment is not adaptive in all temporally varying environments. Further, increased overlap among generations reduces the expected effects of temporal variation on the mean and variance in parental investment. Thus a negative correlation between length of reproductive life and both measures of investment is expected. There is support for the predictions of this model in some animal groups, but not among plants. Possible reasons for the lack of support among plants are discussed and directions for future research aimed at distinguishing adaptive and maladaptive phenotypic variance in parental investment are suggested.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02214158
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  • 9
    Digitale Medien
    Digitale Medien
    Combination chemotherapy with cyclophosphamide, vincristine, procarbazine, and prednisone (COPP) in children with brain tumors (1985)
    Springer
    Journal of neuro-oncology 3 (1985), S. 263-269 
    Details
    ISSN: 1573-7373
    Schlagwort(e): COPP chemotherapy ; brain tumors ; cyclophosphamide ; vincristine ; procarbazine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The chemotherapeutic combination of cyclophosphamide, vincristine, procarbazine, and prednisone (COPP) was used to treat 15 children with recurrent central nervous system tumors and seven children with newly diagnosed brainstem tumors. In patients with recurrent tumors, marginal activity was seen in various histologic types. COPP chemotherapy was clearly ineffective in patients with brainstem tumors. Toxicity consisted of mild to moderate myelosuppression and neurotoxicity.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00165188
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  • 10
    Digitale Medien
    Digitale Medien
    Tomographic renal cortical scintigraphy: Correlation with intravenous urography, computed tomography, ultrasonography, angiography, and nuclear magnetic resonance imaging (1985)
    Springer
    European journal of nuclear medicine 11 (1985), S. 217-220 
    Details
    ISSN: 1619-7089
    Schlagwort(e): Hypernephromas ; Renal cortex imaging ; Columns of Bertin ; Renal tumors
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract This study evaluates single-photon renal tomoscintigraphy (SPECT) in the evaluation of renal masses and correlates this modality, where indicated, with computed tomography (CT), ultrasonography (US), angiography (ANGIO) and nuclear magnetic resonance imaging (NMR). Eight patients with renal cortical lesions detected on intravenous urography (IVP) were evaluated by SPECT and planar nuclear imaging using Tc-99m glucoheptonate (GH). Three of these patients were felt particularly likely to have renal tumors and were additionally evaluated with US, CT, ANGIO and NMR. The five patients with nodules on IVP that were not particularly suggestive of malignancy had functioning, benign, renal tissue accounting for their IVP lesions. Four of five were found by planar-GH nuclear imaging, five/five by SPECT-GH. In addition, SPECT-GH allowed better “confidence” in the normal renal tissue diagnosis in three/five cases. Of the three renal lesions that were highly suggestive of malignancy, two were hypernephromas and one was hypertrophied functioning cortical tissue. All three were correctly identified prospectively on SPECT-GH; however, one hypernephroma was missed on planar-GH. NMR, CT, and ANGIO detected only one of two hypernephromas prospectively (US detected both); all four modalities incorrectly diagnosed the hypertrophied tissue suggestive of malignancy.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00279072
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