Tritium analytics by beta induced X-ray spectrometry

The aim of the Karlsruhe Tritium Neutrino (KATRIN) experiment is a neutrino mass measurement with a sensitivity of 0.2 eV/c2 (90% C.L.) by the investigation of the tritium beta-spectrum. This requires continuous activity monitoring of the windowless gaseous tritium source on the 0.1 % stability level. In this work, the suitability of the beta induced X-ray spectrometry (BIXS) method for high stability and high sensitivity activity monitoring of gaseous tritium sources has been shown

Convergent cascade catalyzed by monooxygenase - alcohol dehydrogenase fusion applied in organic media

With the aim of applying redox-neutral cascade reactions in organic media, fusions of a type II flavin-containing monooxy-genase (FMO-E) and horse liver alcohol dehydrogenase (HLADH) were designed. The enzyme orientation and expression vector were found to influence the overall fusion enzyme activity. The resulting bi-functional enzyme retained the catalytic properties of both individual enzymes. The lyophilized cell free extract containing the bifunctional enzyme was applied for the convergent cascade reaction consisting of cyclobutanone and 1,4-butanediol in different micro-aqueous media with only 5% (v/v) aqueous buffer without any addition of external cofactor. Methyl tert-butyl ether and cyclopentyl methyl ether were found to be the best organic media for the synthesis of γ-butyrolactone resulting in ~27% analytical yield

Kilogram scale throughput performance of the KATRIN tritium handling system

The Karlsruhe Tritium Neutrino (KATRIN) experiment aims to determine the effective mass of the electron antineutrino by investigating the tritium β-spectrum close to the energetic endpoint. To achieve this, there are stringent and challenging requirements on the stability of the gaseous tritium source. The tritium loop system has the task to provide the 95 %. KATRIN started full tritium operation in early 2019. This paper focusses on the observed radiochemical effects and confirms that non-negligible quantities during initial tritium operation have to be expected

A photon dominated region code comparison study

International audienceAims:We present a comparison between independent computer codes, modeling the physics and chemistry of interstellar photon dominated regions (PDRs). Our goal was to understand the mutual differences in the PDR codes and their effects on the physical and chemical structure of the model clouds, and to converge the output of different codes to a common solution. Methods: A number of benchmark models have been created, covering low and high gas densities n = 10^3,105.5 cm-3 and far ultraviolet intensities chi = 10, 105 in units of the Draine field (FUV: 6 Results: We investigated the impact of PDR geometry and agreed on the comparison of results from spherical and plane-parallel PDR models. We identified a number of key processes governing the chemical network which have been treated differently in the various codes such as the effect of PAHs on the electron density or the temperature dependence of the dissociation of CO by cosmic ray induced secondary photons, and defined a proper common treatment. We established a comprehensive set of reference models for ongoing and future PDR model bench-marking and were able to increase the agreement in model predictions for all benchmark models significantly. Nevertheless, the remaining spread in the computed observables such as the atomic fine-structure line intensities serves as a warning that there is still a considerable uncertainty when interpreting astronomical data with our models

First operation of the KATRIN experiment with tritium

The determination of the neutrino mass is one of the major challenges in astroparticle physics today. Direct neutrino mass experiments, based solely on the kinematics of β β -decay, provide a largely model-independent probe to the neutrino mass scale. The Karlsruhe Tritium Neutrino (KATRIN) experiment is designed to directly measure the effective electron antineutrino mass with a sensitivity of 0.2 eV 0.2 eV (90% 90% CL). In this work we report on the first operation of KATRIN with tritium which took place in 2018. During this commissioning phase of the tritium circulation system, excellent agreement of the theoretical prediction with the recorded spectra was found and stable conditions over a time period of 13 days could be established. These results are an essential prerequisite for the subsequent neutrino mass measurements with KATRIN in 2019

Improved Outcomes With Retinoic Acid and Arsenic Trioxide Compared With Retinoic Acid and Chemotherapy in Non-High-Risk Acute Promyelocytic Leukemia: Final Results of the Randomized Italian-German APL0406 Trial

The initial results of the APL0406 trial showed that the combination of all-trans-retinoic acid (ATRA) and arsenic trioxide (ATO) is at least not inferior to standard ATRA and chemotherapy (CHT) in first-line therapy of low- or intermediate-risk acute promyelocytic leukemia (APL). We herein report the final analysis on the complete series of patients enrolled onto this trial