Optimal crossing-free Hamiltonian circuit drawings of Kn

The number of crossing-free Hamiltonian circuits in planar drawings of K_n is studied. In particular, it is shown that for planar drawings of K_n, (1) there are drawings having as many as $\text{(}\text{3}\text{20}\text{)·10}{}^{\mathrm{<mtext>[</mtext><mtext>n</mtext><mtext>3</mtext><mtext>]</mtext>}}$ such circuits and (2) no drawing contains more than $\text{2·6}{}^{\mathrm{n?2}}\text{([}\text{n}\text{2}\text{])!}$     

Numerical solutions for symmetric Bianchi type IX universes

We find numerical solutions for symmetic Bianchi type IX universes. These numerical solutions coincide almost exactly with diagrammatic solutions found previously.     

A correlation energy calculation of the 1s hole state in neon

The Bethe-Goldstone formalism for calculating correlation energy has been applied to the 1s hole state in neon. The binding energy of the 1s electron is computed to be 870.0 eV which is in excellent agreement with experiment.     

Differential inhibition of postnatal brain,spinal cord and body growth by a growth hormone antagonist

Background  

Growth hormone (GH) plays an incompletely understood role in the development of the central nervous system (CNS). In this study, we use transgenic mice expressing a growth hormone antagonist (GHA) to explore the role of GH in regulating postnatal brain, spinal cord and body growth into adulthood. The GHA transgene encodes a protein that inhibits the binding of GH to its receptor, specifically antagonizing the trophic effects of endogenous GH.     

Antimatter and matter production in heavy ion collisions at CERN (The NEWMASS experiment NA52)

Besides the dedicated search for strangelets NA52 measures light (anti)particle and (anti)nuclei production over a wide range of rapidity. Compared to previous runs the statistics has been increased in the 1998 run by more than one order of magnitude for negatively charged objects at different spectrometer rigidities. Together with previous data taking at a rigidity of ?20 GeV/c we obtained $10^6 \bar p, 10^3 \bar d$ and two $\overline {^3 He} $ without centrality requirements. We measured nuclei and antinuclei (p, d, $\bar p,\bar d$ ) near midrapidity covering an impact parameter range of b ～ 2–12 fm. Our results strongly indicate that nuclei and antinuclei are mainly produced via the coalescence mechanism. However, the centrality dependence of the antibaryon to baryon ratios shows that antibaryons are diminished due to annihilation and breakup reactions in the hadron dense environment. The volume of the particle source extracted from coalescence models agrees with results from pion interferometry for an expanding source. The chemical and thermal freeze-out of nuclei and antinuclei appear to coincide with each other and with the thermal freeze-out of hadrons.     

Vinylcarbonates and vinylcarbamates: Biocompatible monomers for radical photopolymerization

The last decade has seen a remarkable interest in the use of biocompatible and biodegradable polymers as scaffolds for tissue engineering. The fabrication of 3D scaffolds by lithography‐based additive manufacturing technology (AMT) represents an appealing approach. As poly(lactic acid), the state of the art biocompatible and biodegradable material, cannot be processed by these photopolymerization‐based techniques, it has so far been necessary to use selected (meth)acrylates. By developing new photopolymers based on vinyl carbonates and vinyl carbamates as a reactive group we have been able to avoid most of the disadvantages of classical (meth)acrylate‐based photopolymers. The new generation of biocompatible monomers show low cytotoxicity, have good storage stability, and are sufficiently photoreactive to be structured by lithography based AMT. The mechanical properties and rates of degradation of the polymers can be easily tuned over a broad range. Degradation results in the formation of nonacidic and nontoxic degradation products of low molecular weight that can be easily transported within the human body. Initial in vivo tests showed significant osseointegration of the 3D cellular scaffolds and no signs of implant rejection. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

A masked-alkene metathesis-based synthesis of isopulo’upone

A metathesis-based formal synthesis of (±)-isopulo’upone has been completed featuring a masked olefin metathesis/elimination sequence followed by an intramolecular Diels-Alder reaction to construct the 5,6-fused bicyclic core.     

Energy concentration for the Landau–Lifshitz equation

For the Landau–Lifshitz equation on a domain with three space dimensions, we consider energy concentration phenomena arising in the context of weakly convergent sequences of solutions. The concentration measure can be interpreted as a family of generalized curves. We establish a connection to a geometric flow.