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Matthias Wagner

Publications and source records attributed to Matthias Wagner.

29 records · Page 2Linked to original sources
PubMed2004

ELERA: a WWW application for evaluating and developing radiologic skills and knowledge.

RATIONALE AND OBJECTIVES: To provide an online facility for evaluating, comparing, and building expertise in radiologic anatomy and clinical radiology. MATERIALS AND METHODS: Project participants were recruited from an experienced special interest group of students at the local medical school. A rigid protocol was agreed upon, defining and assigning the tasks of case selection, data entry, test task creation, and peer review. The presentation of test tasks and evaluation of user input was implemented as a custom web application. RESULTS: ELERA, an online assessment and learning resource based on 1,650 pathologic cases and 550 anatomy cases, was created and made publicly accessible as a world wide web application. CONCLUSION: The project design facilitated the creation of a free, highly accessible and user-friendly resource that offers capabilities for individual longitudinal and intersubject comparative assessment.

Computer-Assisted Instruction↗
PubMed2004

Lack of sensitivity of primary Fanconi's anemia fibroblasts to UV and ionizing radiation.

Clinical observations and theoretical considerations suggest some degree of radiosensitivity in Fanconi's anemia (FA), but experimental evidence remains controversial. We tested the sensitivity of primary skin fibroblast cultures from all known FA complementation groups to ionizing radiation and ultraviolet light using conventional cell growth and colony formation assays. In contrast to previous studies, and because FA fibroblasts grow and clone poorly at ambient oxygen, we performed our sensitivity tests under hypoxic cell culture conditions. Fibroblast strains from healthy donors served as negative controls and those from patients with ataxia telangiectasia (AT) and Cockayne syndrome (CS) as positive controls. We observed interstrain variation but no systematic difference in the response of FA and non-FA control fibroblasts to ionizing radiation. After exposure to UV radiation, only complementation group A, G and D2 strains displayed values for colony formation EC50 that were intermediate between those for the negative and positive controls. Because of considerable interstrain variation, minor alterations of the response of individual FA strains to ionizing and UV radiation should be interpreted with caution and should not be taken as evidence for genotype-specific sensitivities of primary FA fibroblasts. All together, our data indicate neither systematic nor major sensitivities of primary FA fibroblast cultures of any complementation group grown under hypoxic cell culture conditions to ionizing or UV radiation.

Cell Division↗
PubMed2003

The twinned structure of ferricenyltrifluoroborate.

Crystals of the title compound, [Fe(C(5)H(5))(C(5)H(4)BF(3))], are monoclinic and twinned. The twinning initially resulted in a misleading unit-cell assignment. The formal oxidation state of Fe is 3+, and the crystal packing consists of intermolecular C--H...F and pi-pi interactions.

Journal Article↗
PubMed2003

A novel type of phosphide: synthesis and X-ray crystal structure analysis of (tBu3Si)3P4Li3.

The tetraphosphides (tBu3Si)3P4M3 (M = Li, Na) and (tBu2PhSi)3P4Na3 have been synthesized in high yield from the reaction of 3 equivalents of the silanides tBu3SiM (M = Li, Na) and tBu2PhSiNa with P4 in benzene. (tBu3Si)3P4M3 (M = Li, Na) are transformed into the unsaturated triphosphides (tBu3Si)2P3M (M = Li, Na) and tBu3SiPM2 in tetrahydrofuran at ambient temperature.

Journal Article↗
PubMed2003

One- and three-dimensional infinite arrays of Cu(I) ions exhibited by [Cu(NH3)2]Br and [Cu(NH3)Cl] in the solid state.

In the solid state, [Cu(NH3)Cl] forms a three-dimensional network with each Cu(I) ion being surrounded by three other Cu(I) centres in a trigonal-planar fashion [Cu...Cu = 2.979(1) A; cubic space group I2(1)3], whereas in [Cu(NH3)2]Br the cations establish infinite linear (Cu...Cu) chains spanning the crystal lattice [Cu...Cu = 2.931(1) A; monoclinic space group C2/c].

Journal Article↗
PubMed2002

Isomorphism and phase transition in triferrocenylboroxine and triferrocenylborazine.

The crystal structures of triferrocenylboroxine, [Fe(3)(C(5)H(5))(3)(C(15)H(12)B(3)O(3))], (I), and triferrocenylborazine, [Fe(3)(C(5)H(5))(3)(C(15)H(15)B(3)N(3))], (II), are isomorphous. At room temperature, the space group is Cmc2(1) and the molecules have crystallographic m symmetry. A reversible phase transition occurs at 283(2)K for (I) and at 263(5)K for (II). In the low-temperature phase, the space group of both compounds is P2(1) and the molecules no longer have internal symmetry. Intermolecular C-H...pi interactions are enhanced in the low-temperature phase.

Journal Article↗
PubMed2002

[Multi-slice CT of aortocoronary venous bypasses and mammary artery bypasses: evaluation of bypasses and their anastomoses].

OBJECTIVE: To assess aortocoronary grafts and internal mammary artery bypasses by means of EKG-triggered contrast-enhanced multi-slice spiral CT, and to evaluate the diagnostic accuracy of this new imaging modality. MATERIAL AND METHODS: 59 patients with up to 5 aortocoronary grafts and/or internal mammary artery bypasses per patient were examined with regard to bypass morphology, the free passage, and the proximal as well as the distal anastomoses using multislice computed tomography. Axial source images were calculated by means of retrospective triggering at different diastolic delay times, and were postprocessed in several planes with the multiplanar volume reconstruction (MPVR) software. RESULTS: On the pre-condition that data sets were acquired at sinus rhythm and at a heart rate lower than 65/min, aortocoronary grafts and internal mammary artery bypasses could be depicted in adequate diagnostic quality in about 80% of all cases with contrast-enhanced multi-slice spiral CT. Both, the free passage of the bypasses as well as the morphology of the proximal anastomoses were sufficiently assessed with multiplanar volume reconstruction (MPVR), whereas the distal anastomoses couldn't be depicted sufficiently in 20% of all cases. CONCLUSION: As a non-invasive method, contrast-enhanced and ECG-triggered multi-slice spiral computed tomography has gained diagnostic potential for the accurate visualization of aortocoronary grafts and the internal mammary artery bypasses.

Aged↗
PubMed1997

Ferrocene-Based Tris(1-pyrazolyl)borates: A New Approach to Heterooligometallic Complexes and Organometallic Polymers Containing Transition Metal Atoms in the Backbone.

Starting from mono- and bifunctional ferrocene-based tris(1-pyrazolyl)borates, a novel route to oligonuclear complexes is presented, which incorporates transition metal centers differing substantially in their chemical nature. Both binuclear organometallics FcB(pz)(3)ML(n)() (Fc: ferrocenyl. pz: 1-pyrazolyl. ML(n)(): Tl, 1-Tl; Mo(CO)(3)Li, 1-MoLi; Mo(CO)(2)(eta(3)-methylallyl), 1-Mo; ZrCl(3), 1-Zr) and trinuclear complexes 1,1'-fc[B(pz)(3)ML(n)()](2) (fc: ferrocenylene. ML(n)(): Tl, 2-Tl; Mo(CO)(3)Li, 2-MoLi; Mo(CO)(2)(eta(3)-methylallyl), 2-Mo) have been prepared. The trinuclear compound [FcB(4-SiMe(3)pz)(3)](2)Fe, 1-FeSi, has been investigated as a model system for organometallic coordination polymers, consisting of the bifunctional linker 1,1'-fc[B(pz)(3)](2)(2)(-) and transition metal ions M(n)()(+). X-ray crystallography shows 1-Tl to establish a polymeric structure in the solid state, while 1-Mo features the usual tridentate coordination mode of the scorpionate ligand (C(25)H(25)BFeMoN(6)O(2); a = 8.756(1) Å, b = 12.154(1) Å, c = 12.927(1) Å, alpha = 105.26(1) degrees, beta = 102.29(1) degrees, gamma = 105.09(1) degrees; triclinic space group P&onemacr;; Z = 2). With the exception of 1,2-Tl, the anodic oxidation of the ferrocene moiety is generally reversible; cyclic voltammetry measurements indicate the two Mo centers in 2-Mo and the two Fc moieties in 1-FeSi to be noncommunicating.

Journal Article↗