The point and line space of a compact projective plane are homeomorphic

The local Hopf bundles at the points and lines of a compact projective plane with manifold lines are all weakly equivalent. In particular, the point space and the line space of such a projective plane are homeomorphic. This is a consequence of the following topological result. Theorem. Let $\xi,\xi'$ be orientable topological $\mathbb{R}^n$ -bundles over an n-dimensional CW-complex. If $\xi$ and $\xi'$ are fibre homotopy equivalent and stably equivalent, then $\xi$ and $\xi'$ are equivalent. Received: 10 December 1998 / Accepted: 18 May 1999     

Processing of Three-Dimensional Laser Sintered Polyetheretherketone Composites and Testing of Osteoblast Proliferation in vitro

Summary: The following investigation focuses on polyetheretherketone (PEEK) for bone substitutes intended for maxillofacial surgery. Different three-dimensional discs with a diameter of 12 mm and a height of 3 mm were laser sintered. As filler materials nano-sized carbon black and β-tricalciumphosphate powder with an average grain size of 35 µm were used. Human osteoblasts were cultivated on the discs and examined with scanning electron microscopy. Cell vitality and cell growth was investigated. The data shows that PEEK surfaces does not suppress osteoblast proliferation.     

Are formalin‐fixed and paraffin‐embedded tissues fit for proteomic analysis?

Formalin‐fixed and paraffin‐embedded (FFPE)–tissue archives are potential treasure troves in the search for clinically interesting specimens. However, while the FFPE‐treatment provides excellent conservation of the three‐dimensional structure of the tissue and prevents degradation over decades, it also introduces numerous nonspecific and irreversible protein modifications. In this study, we have evaluated several published workflows for FFPE‐tissue by fit‐for‐purpose proteomics technologies. We demonstrate that many protein modifications and cross‐links remain after treatment and conclude that the proteomics of FFPE‐tissue is of value, but clear‐cut limitations must be kept in mind. The analysis of abundant proteins in FFPE is straightforward, but confident identification of low‐level proteins and/or biologically relevant modifications is seriously hampered by the FFPE‐treatment. Peptide assignment should only be performed on high‐quality spectra, even if this is at the cost of lower numbers of protein IDs. As Yergey and Coorssen stated in 2015: “Data quality is considered the primary criterion, and we thus emphasize that the standards of Analytical Chemistry must apply throughout any proteomic analysis.”     

Synthesis of Air‐Stable,Volatile Uranium(IV) and (VI) Compounds and Their Gas‐Phase Conversion To Uranium Oxide Films

Four air‐stable, volatile uranium heteroarylalkenolates have been synthesized and characterized by three synthetic approaches and their gas phase deposition to uranium oxide films has been examined.     

Kohle und Koks

Ohne Zusammenfassung     

Implicit representation of generalized variable upper bounds in linear programming

In certain linear programs, especially those derived from integer programs, large numbers of constraints may have very simple form. Examples are:x _ij 1 (simple upper bounds [SUB]), _i x _ij = 1 (generalized upper bounds [GUB]) andx _ij y _i (variable upper bounds [VUB]). A class of constraints called generalized VUB [GVUB] is introduced which includes GUB and VUB as special cases. Also introduced is a method for representing GVUB constraints implicitly within the mechanics of the simplex method.Research supported in part by the Mobil Oil Corporation.