Towers and fibered products of model categories

Given a left Quillen presheaf of localized model structures, we study the homotopy limit model structure on the associated category of sections. We focus specifically on towers and fibered products of model categories. As applications we consider Postnikov towers of model categories, chromatic towers of spectra and Bousfield arithmetic squares of spectra. For spectral model categories, we show that the homotopy fiber of a stable left Bousfield localization is a stable right Bousfield localization

Rigidity and exotic models for v1-local G-equivariant stable homotopy theory

We prove that the v1-local G-equivariant stable homotopy category for G a finite group has a unique G-equivariant model at p=2. This means that at the prime 2 the homotopy theory of G-spectra up to fixed point equivalences on K-theory is uniquely determined by its triangulated homotopy category and basic Mackey structure. The result combines the rigidity result for K-local spectra of the second author with the equivariant rigidity result for G-spectra of the first author. Further, when the prime p is at least 5 and does not divide the order of G, we provide an algebraic exotic model as well as a G-equivariant exotic model for the v1-local G-equivariant stable homotopy category, showing that for primes p≥5 equivariant rigidity fails in general

Mechanical properties and bioanalytical characterization for a novel non-toxic flexible photopolymer formulation class

We present herein a new class of resin formulations for stereolithography, named FlexSL, with a broad bandwidth of tunable mechanical properties. The novel polyether(meth)acrylate based material class has outstanding material characteristics in combination with the advantages of being a biocompatible (meth)acrylate based processing material. FlexSL shows very promising results in several initial biocompatibility tests. This emphasizes its non-toxic behavior in a biomedical environment, caused mainly by the (meth)acrylate based core components. A short overview of mechanical and processing properties will be given in the end. The herein presented novel FlexSL materials show a significant lower cytotoxicity in contrast to commercial applied acrylic stereolithography resins. Further biocompatibility tests according to ISO 10993 protocols are planned. On the one hand, there are technical applications for this material (e.g. flaps, tubes, hoses, cables, sealing parts, connectors and other technical rubber-like applications), and on the other hand, broad fields of potential biomedical applications in which the FlexSL materials can be beneficial are obvious. Especially these could be small series production of medical products with special flexible material requirements. In addition, the usage for individual soft hearing aid shells, intra-operative planning services and tools like intra-op cutting templates and sawing guides is very attractive. The possibility to modify the FlexSL resins also for high-resolution applications makes it possible to manufacture now very flexible micro-prototypes with outstanding material characteristics and very fine structures with a minimum resolution of 20 mym and a layer thickness of minimal 5 myrn. These resin formulations are applicable and adjustable to other stereolithographic equipment available on the market