Direct <i>Q</i> -Value Determination of the <i>β^-</i> Decay of ¹⁸⁷Re

The cyclotron frequency ratio of 187Os29+ to 187Re29+ ions was measured with the Penning-trap mass spectrometer PENTATRAP. The achieved result of R=1.000 000 013 882(5) is to date the most precise such measurement performed on ions. Furthermore, the total binding-energy difference of the 29 missing electrons in Re and Os was calculated by relativistic multiconfiguration methods, yielding the value of ΔE=53.5(10)  eV. Finally, using the achieved results, the mass difference between neutral 187Re and 187Os, i.e., the Q value of the β-− decay of 187Re, is determined to be 2470.9(13) eV

An Organic Metal/Silver Nanoparticle Finish on Copper for Efficient Passivation and Solderability Preservation

For the first time, a complex formed by polyaniline (in its organic metal form) and silver has been deposited on copper in nanoparticulate form. When depositing on Cu pads of printed circuit boards it efficiently protects against oxidation and preserves its solderability. The deposited layer has a thickness of only nominally 50 nm, containing the Organic Metal (conductive polymer), polyaniline, and silver. With >90% (by volume), polyaniline (PAni) is the major component of the deposited layer, Ag is present equivalent to a 4 nm thickness. The Pani–Ag complex is deposited on Cu in form of about 100 nm small particles. Morphology, electrochemical characteristics, anti-oxidation and solderability results are reported

Electrostatic immobilization of antimicrobial peptides on polyethylenimine and their antibacterial effect against Staphylococcus epidermidis

Staphylococcus epidermidis is a gram-positive bacterium, and one of the most prevalent causes of nosocomial infections due to its strong ability to form biofilms on catheters and surgical implants. Here we explore the antimicrobial properties of Tet-124 peptides, which are part of the innate defense against different multicellular organisms in nature. Two different Tet-124 peptides were immobilized on a polyethylenimine (PEI) film to determine their impact on the antimicrobial properties: KLWWMIRRW (Tet-124), which contains only natural amino acids, and KLWWMIRRWG-(F-Br)-G (F-Br- 4-Bromophenylalanine), a modified Tet-124 sequence with the addition of an unnatural amino acid. The immobilization was obtained as a result of the electrostatic interaction between PEI amino groups and the C-terminal carboxylic groups of tryptophan and glycine amino acids of Tet-124 and Tet-124-Br peptides, respectively. The process was monitored and studied by water contact angle, Atomic Force Microscopy (AFM), X-ray Photoelectron Spectroscopy (XPS) and Quartz Crystal Microbalance with Dissipation (QCM-D) measurements. The antibacterial effect of our samples against S. epidermis was evaluated by the spread plate counting method, and cytotoxicity was tested using fibroblast cultures. Our results indicate the feasibility to immobilize electrostatically both Tet-124 peptides for biomedical application

High-resolution and low-background 163^{163}Ho spectrum: interpretation of the resonance tails

The determination of the effective electron neutrino mass via kinematic analysis of beta and electron capture spectra is considered to be model-independent since it relies on energy and momentum conservation. At the same time the precise description of the expected spectrum goes beyond the simple phase space term. In particular for electron capture processes, many-body electron-electron interactions lead to additional structures besides the main resonances in calorimetrically measured spectra. A precise description of the $^{163}$Ho spectrum is fundamental for understanding the impact of low intensity structures at the endpoint region where a finite neutrino mass affects the shape most strongly. We present a low-background and high-energy resolution measurement of the $^{163}$Ho spectrum obtained in the framework of the ECHo experiment. We study the line shape of the main resonances and multiplets with intensities spanning three orders of magnitude. We discuss the need to introduce an asymmetric line shape contribution due to Auger–Meitner decay of states above the auto-ionisation threshold. With this we determine an enhancement of count rate at the endpoint region of about a factor of 2, which in turn leads to an equal reduction in the required exposure of the experiment to achieve a given sensitivity on the effective electron neutrino mass

The electron capture in 163^{163}Ho experiment – ECHo

Neutrinos, and in particular their tiny but non-vanishing masses, can be considered one of the doors towards physics beyond the Standard Model. Precision measurements of the kinematics of weak interactions, in particular of the $^{3}$H β-decay and the $^{163}$Ho electron capture (EC), represent the only model independent approach to determine the absolute scale of neutrino masses. The electron capture in $^{163}$Ho experiment, ECHo, is designed to reach sub-eV sensitivity on the electron neutrino mass by means of the analysis of the calorimetrically measured electron capture spectrum of the nuclide $^{163}$Ho. The maximum energy available for this decay, about 2.8 keV, constrains the type of detectors that can be used. Arrays of low temperature metallic magnetic calorimeters (MMCs) are being developed to measure the $^{163}$Ho EC spectrum with energy resolution below 3 eV FWHM and with a time resolution below 1 μs. To achieve the sub-eV sensitivity on the electron neutrino mass, together with the detector optimization, the availability of large ultra-pure $^{163}$Ho samples, the identification and suppression of background sources as well as the precise parametrization of the $^{163}$Ho EC spectrum are of utmost importance. The high-energy resolution $^{163}$Ho spectra measured with the first MMC prototypes with ion-implanted $^{163}$Ho set the basis for the ECHo experiment. We describe the conceptual design of ECHo and motivate the strategies we have adopted to carry on the present medium scale experiment, ECHo-1K. In this experiment, the use of 1 kBq $^{163}$Ho will allow to reach a neutrino mass sensitivity below 10 eV/c$^{2}$. We then discuss how the results being achieved in ECHo-1k will guide the design of the next stage of the ECHo experiment, ECHo-1M, where a source of the order of 1 MBq $^{163}$Ho embedded in large MMCs arrays will allow to reach sub-eV sensitivity on the electron neutrino mass

An innovative, preventive acting “bioinspired” antimicrobial surface based on peptides for space and Earth

Antimicrobial surfaces are a well suited technology to prevent and reduce microbial loads in sensitive areas, where high humidity and temperature levels are causing increased microbial loads. These can endanger human health, health of organisms e.g. in bioregenerative life-support systems as well as technical equipment. Antimicrobial surfaces are preventively beneficial • in spaceflight – e.g. in confined environments in LEO and during exploration activities, to support breeding activities of e.g. algae in bioreactors and for biological experiments, and furthermore to meet the COSPAR planetary protection policy • as well as also on Earth - in hygiene areas during medical activities and food handling, in swimming baths, bathrooms, public transportation, submarines, greenhouses etc. For its dedicated use in space as well as on Earth, antimicrobial surfaces must be free of any toxic substance, otherwise higher non-target organisms would be affected. That means, that synthetic chemicals, silver, copper etc., as used until now, are not a suited solution - which in addition might lead to resistances of the bacteria to these toxic substances and are acting rather unspecific. A suited alternative to overcome these problems are bioinspired technologies as using antimicrobial peptides from nature (e.g. from frog skin etc.), immobilized on surfaces. High flexibility concerning the microbial target, acting specifically, low toxicity and an absence of resistances are the main advantages. As a logical step, the goal of the ESA-funded project BALS (Bioinspired antimicrobial lacquer for space) was the development of a new innovative antimicrobial acting lacquer based on peptides. Project partners were OHB System, Fraunhofer Institute for Manufacturing Technology and Advanced Materials (IFAM) (both Bremen, Germany) as well as the German Aerospace Center, Institute of Aerospace Medicine (Cologne, Germany). The developed antimicrobial lacquer with immobilized peptides showed an antimicrobial activity against S. cohnii and E. coli, compared to a reference lacquer without peptides. Its adhesion strength on space relevant substrates was demonstrated in a ECSS-Q-70-13A-test series, measuring the peel and pull-off strength using pressure-sensitive tapes. In addition, the absence of effects on higher organisms and the environment was shown in a laboratory aquatic biological multispecies test system (AquaHab®). With the successful demonstration of feasibility and use (TRL 4) of such a bioinspired antimicrobial lacquer and including these promising test results, all preconditions are now given for the further development and qualification until a full commercial exploitation, ready to be used in application fields in space and on Earth

A NEW PREVENTIVE ACTING BIOINSPIRED ANTIMICROBIAL SURFACE - ACTUAL STATUS AND FIRST RESULTS

Antimicrobial surfaces are a highly promising approach in preventing/ reducing microbial loads in sensitive areas. There, high humidity and temperature levels are causing microbial contamination - endangering human health, health of organisms e.g. in bioregenerative life-support systems as well as technical equipment. Antimicrobial surfaces are beneficial • in spaceflight - w.r.t. activities in confined environments in LEO and during exploration activities - to support breeding activities of e.g. algae in bioreactors, biological experiments and to meet the COSPAR planetary protection policy • as well as on Earth - in hygiene areas during medical activities and food handling, in swimming baths, bathrooms etc.. For confined environments in space as well as on Earth, antimicrobial surfaces must be free of any toxic substance, otherwise higher non-target organisms would be affected. Thus, synthetic chemicals, silver, copper etc., as used until now, are not a suited solution, which in addition might lead to resistances of the bacteria to these toxic substances and are acting rather unspecific. Bioinspired technologies as using antimicrobial peptides from nature (e.g. from frog skin etc.), immobilised on surfaces, are a suited alternative. High flexibility concerning the microbial target, low toxicity and an absence of resistances are the main advantages. As a consequence, the goal of the ESA-funded project BALS (Bio-inspired antimicrobial lacquer for space) was the development of a new innovative antimicrobial acting lacquer based on peptides. Project partners were OHB System, Fraunhofer Institute for Manufacturing Technology and Advanced Materials (IFAM) (both Bremen, Germany) as well as the German Aerospace Center, Institute of Aerospace Medicine (Cologne, Germany). An overview about goals, technology and test results (w.r.t. antimicrobial activity, adhesion on substrates as well as absence of effects on higher organisms) of the BALS activity will be given at the symposium. Furthermore, an outlook about the next development and qualification steps until routine application in space and on Earth will be part of the presentation

Multi-step fractionation as a tool for enhanced valorization of technical lignins

The valorisation of lignin obtained as a by-product of the pulping and biofuel industries is one of the most promising topics in the bioresource field. Despite its potential value as the only massively available aromatic biopolymer feedstock, technical lignin is nowadays mostly burnt as low cost energy source because of its chemical recalcitrance. The high heterogeneity of this material, largely dependent on the different vegetal sources and the specific biomass recovery methods, restricts its direct use and hinders also the optimization of depolymerisation approaches. The development of effective technical lignin fractionation strategies is therefore today one of the most challenging topic in the green chemistry field. In this study, the fractionation of two industrial commercial lignins was performed by a three step procedure set-up either in aqueous or in environmentally friendly organic solvents in order to obtain sustainable and scalable processes. The first step consisted in a microfiltration or a Soxhlet extraction in function of the solvent used. Then a cascade membrane ultrafiltration allowed to obtain at the end three refined lignin fractions (see Figure below) which were fully characterized, presenting better defined physico-chemical properties compared to the starting raw material. The availability of technical lignin fractions with tailored and reproducible characteristics allows the set-up of enhanced lignin valorization strategies for the development of bio-based polymers and preparation of key platform chemicals, thereby paving the way for an effective exploitation and valorization of this remarkable resource. Allegretti, A.; Fontanay, S.; Krauke, Y.; Luebbert, M.; Strini, A.; Troquet, J.; Turri, S.; Griffini, G.; D’Arrigo, P. ACS Sustainable Chem. Eng. 2018, 6, 9056-9064. Acknoledgements: ValorPlus Project (grant agreement no FP7-KBBE-2013-7-613802)