Laser Additive Manufacturing of Gas Permeable Structures

Laser additive manufacturing offers a variety of new design possibilities. In mold making laser additive manufactured inserts with conformal cooling channels are already state of the art. Pneumatic ejectors for injection molds are a new application for laser additive manufacturing. The pneumatic ejectors require a durable gas permeable material. This material is produced by placing the scan vectors for the laser additive manufacturing process in a defined pattern. Trials with different plastics proofed the function and reliability of the pneumatic ejector concept in the injection molding cycle

Synthesis of an Antimicrobial Enterobactin-Muraymycin Conjugate for Improved Activity Against Gram-Negative Bacteria

Overcoming increasing antibiotic resistance requires the development of novel antibacterial agents that address new targets in bacterial cells. Naturally occurring nucleoside antibiotics (such as muraymycins) inhibit the bacterial membrane protein MraY, a clinically unexploited essential enzyme in peptidoglycan (cell wall) biosynthesis. Even though a range of synthetic muraymycin analogues has already been reported, they generally suffer from limited cellular uptake and a lack of activity against Gram-negative bacteria. We herein report an approach to overcome these hurdles: a synthetic muraymycin analogue has been conjugated to a siderophore, i. e. the enterobactin derivative EntKL, to increase the cellular uptake into Gram-negative bacteria. The resultant conjugate showed significantly improved antibacterial activity against an efflux-deficient E. coli strain, thus providing a proof-ofconcept of this novel approach and a starting point for the future optimisation of such conjugates towards potent agents against Gram-negative pathogens

Influence of the Additive Manufacturing System on the Design of a Microrectification Apparatus [Einfluss des additiven Fertigungsverfahrens auf die Gestalt einer Mikrorektifikationsapparatur]

Die additive Fertigung eröffnet auch in der Verfahrenstechnik neue Möglichkeiten. In der Entwicklung kompakter Rektifikationsapparate sind Vorteile für die Herstellung ebenso wie für die Trennleistung denkbar. Der Designprozess für kompakte, fertigungsgerechte Mikrorektifikationsapparate für zwei Metall-3D-Druck-Verfahren wird gezeigt: Binder-Jetting (BJT/M) und pulverbettbasiertes Schmelzen von Metallen mittels Laser (PBF-LB/M). Restriktionen der Verfahren, z. B. in Bezug auf Überhänge und die Entpulverungs- und Sinterschritte, werden erklärt. Die erste Charakterisierung der gedruckten Teile zeigt, dass die Entwürfe vielversprechend sind

Cyrhetrenylaniline and new organometallic phenylimines derived from 4- and 5-nitrothiophene: Synthesis, characterization, X-Ray structures, electrochemistry and in vitro anti-T. brucei activity

A novel series of cyrhetrenyl (3a-4a) and ferrocenyl (3b-4b) Schiff bases were synthesized through a condensation reaction, between the known 4-ferrocenylaniline (2b) or the unreported 4-cyhretrenylaniline (2a) with 4- or 5-nitrothiophenecarboxaldehyde. The structure of 2a and the new Schiff bases have been elucidated using conventional spectroscopic techniques (FT-IR, 1H and 13C NMR), mass spectrometry, and single-crystal X-ray diffraction analysis of compounds 2a, 4a and 3b. Cyclic voltammetry of organometallic phenylimines derived from 5-nitrothiophene showed NO2 group reduction potentials (E1/2z 0.575 V) that were more anodic than those registered for their 4-nitro analogues (E1/2z 0.981 V). All organometallic imines were tested against the bloodstream form of Trypanosoma brucei. Evaluation indicated that the most active complexes are the 5-nitrothiophene derivatives, 4a, which were remarkably more active than nifurtimox. In addition, complex 4b resulted in less toxicity to host L6 cells than nifurtimox. The results revealed that the electronic effects of cyrhetrene and ferrocene are not an influential factor in E1/2 and anti-Trypanosoma brucei activity for these new imines, which is probably due to the non-coplanarity of the [(h5-C5H4)-C6H4-N=CH-(C4H2S)] system

(Z)-3-(4-Bromo­anilino)-1-ferrocenylbut-2-en-1-one

In the title compound, [Fe(C5H5)(C15H13BrNO)], formed from the reaction of ferrocenoylacetone and 4-bromo­aniline, the mol­ecular structure is stabilized by an intra­molecular N—H⋯O hydrogen bond between the amine and carbonyl groups

Constraints on the high-density nuclear equation of state from the phenomenology of compact stars and heavy-ion collisions

A new scheme for testing nuclear matter equations of state (EsoS) at high densities using constraints from neutron star phenomenology and a flow data analysis of heavy-ion collisions is suggested. An acceptable EoS shall not allow the direct Urca process to occur in neutron stars with masses below $1.5~M_{\odot}$, and also shall not contradict flow and kaon production data of heavy-ion collisions. Compact star constraints include the mass measurements of 2.1 +/- 0.2 M_sun (1 sigma level) for PSR J0751+1807, of 2.0 +/- 0.1 M_sun from the innermost stable circular orbit for 4U 1636-536, the baryon mass - gravitational mass relationships from Pulsar B in J0737-3039 and the mass-radius relationships from quasiperiodic brightness oscillations in 4U 0614+09 and from the thermal emission of RX J1856-3754. This scheme is applied to a set of relativistic EsoS constrained otherwise from nuclear matter saturation properties with the result that no EoS can satisfy all constraints simultaneously, but those with density-dependent masses and coupling constants appear most promising.Comment: 15 pages, 8 figures, 5 table

Diquark Condensates and Compact Star Cooling

The effect of color superconductivity on the cooling of quark stars and neutron stars with large quark cores is investigated. Various known and new quark-neutrino processes are studied. As a result, stars being in the color flavor locked (CFL) color superconducting phase cool down extremely fast. Quark stars with no crust cool down too rapidly in disagreement with X-ray data. The cooling of stars being in the N_f =2 color superconducting (2SC) phase with a crust is compatible with existing X-ray data. Also the cooling history of stars with hypothetic pion condensate nuclei and a crust does not contradict the data.Comment: 10 pages, 5 figures, accepted for publication in Ap

Phase diagrams in nonlocal PNJL models constrained by Lattice QCD results

Based on lattice QCD-adjusted SU(2) nonlocal Polyakov--Nambu--Jona-Lasinio (PNJL) models, we investigate how the location of the critical endpoint in the QCD phase diagram depends on the strenght of the vector meson coupling, as well as the Polyakov-loop (PL) potential and the form factors of the covariant model. The latter are constrained by lattice QCD data for the quark propagator. The strength of the vector coupling is adjusted such as to reproduce the slope of the pseudocritical temperature for the chiral phase transition at low chemical potential extracted recently from lattice QCD simulations. Our study supports the existence of a critical endpoint in the QCD phase diagram albeit the constraint for the vector coupling shifts its location to lower temperatures and higher baryochemical potentials than in the case without it.Comment: 23 pages, 10 figures. Version accepted in Phys. Part. Nucl. Lett. (to appear), references adde