Canonical multi-valued input Reed-Muller trees and forms

There is recently an increased interest in logic synthesis using EXOR gates. The paper introduces the fundamental concept of Orthogonal Expansion, which generalizes the ring form of the Shannon expansion to the logic with multiple-valued (mv) inputs. Based on this concept we are able to define a family of canonical tree circuits. Such circuits can be considered for binary and multiple-valued input cases. They can be multi-level (trees and DAG's) or flattened to two-level AND-EXOR circuits. Input decoders similar to those used in Sum of Products (SOP) PLA's are used in realizations of multiple-valued input functions. In the case of the binary logic the family of flattened AND-EXOR circuits includes several forms discussed by Davio and Green. For the case of the logic with multiple-valued inputs, the family of the flattened mv AND-EXOR circuits includes three expansions known from literature and two new expansions

Measurement of the 70Ge(n,γ) cross section up to 300 keV at the CERN n_TOF facility

Neutron capture data on intermediate mass nuclei are of key importance to nucleosynthesis in the weak component of the slow neutron capture processes, which occurs in massive stars. The (n,γ) cross section on 70Ge, which is mainly produced in the s process, was measured at the neutron time-of-flight facility n_TOF at CERN. Resonance capture kernels were determined up to 40 keV neutron energy and average cross sections up to 300 keV. Stellar cross sections were calculated from kT =5 keV tokT =100 keV and are in very good agreement with a previous measurement by Walter and Beer (1985) and recent evaluations. Average cross sectionsareinagreementwithWalterandBeer(1985)overmostoftheneutronenergyrangecovered,whilethey aresystematicallysmallerforneutronenergiesabove150keV.Wehavecalculatedisotopicabundancesproduced in s-process environments in a 25 solar mass star for two initial metallicities (below solar and close to solar). While the low metallicity model reproduces best the solar system germanium isotopic abundances, the close to solar model shows a good global match to solar system abundances in the range of mass numbers A=60–80.Austrian Science Fund J3503Adolf Messer Foundation ST/M006085/1European Research Council ERC2015-StGCroatian Science Foundation IP-2018-01-857

Radiative neutron capture cross-section measurement of ge isotopes at n_TOF CERN facility and its importance for stellar nucleosynthesis

This manuscript summarizes the results of radiative neutron capture cross-section measurements on two stable germanium isotopes, 70Ge and 73Ge. Experiments were performed at the n_TOF facility at CERN via the time-of-flight technique, over a wide neutron energy range, for all stable germanium isotopes (70,72,73,74, and 76). Results for 70Ge [Phys. Rev. C 100, 045804 (2019)] and 73Ge [Phys. Lett. B 790, 458 (2019)] are already published. In the field of nuclear structure, such measurements allow to study excited levels close to the neutron binding energy and to obtain information on nuclear properties. In stellar nucleosynthesis research, neutron induced reactions on germanium are of importance for nucleosynthesis in the weak component of the slow neutron capture processes. © 2021 Polish Academy of Sciences. All rights reserved.Austrian Science Fund FWFUK Science and Facilities Council ST/M006085/1European Research Council (ERC) ERC-2015-StG No. 677497National Science Center. Poland UMO2016/22/M/ST2/00183MSMT of the Czech Republic IP-2018-01-8570Croatian Science Foundation IP-2018-01-857

Reversible acetylation regulates acetate and propionate metabolism in Mycobacterium smegmatis

Carbon metabolic pathways are important to the pathogenesis of Mycobacterium tuberculosis, the causative agent of tuberculosis. However, extremely little is known about metabolic regulation in mycobacteria. There is growing evidence for lysine acetylation being a mechanism of regulating bacterial metabolism. Lysine acetylation is a post-translational modification in which an acetyl group is covalently attached to the side chain of a lysine residue. This modification is mediated by acetyltransferases, which add acetyl groups, and deacetylases, which remove the acetyl groups. Here we set out to test whether lysine acetylation and deacetylation impact acetate metabolism in the model mycobacteria Mycobacterium smegmatis, which possesses 25 candidate acetyltransferases and 3 putative lysine deacetylases. Using mutants lacking predicted acetyltransferases and deacetylases we showed that acetate metabolism in M. smegmatis is regulated by reversible acetylation of acetyl-CoA synthetase (Ms-Acs) through the action of a single pair of enzymes: the acetyltransferase Ms-PatA and the sirtuin deacetylase Ms-SrtN. We also confirmed that the role of Ms-PatA in regulating Ms-Acs regulation depends on cAMP binding. We additionally demonstrated a role for Ms-Acs, Ms-PatA and Ms-SrtN in regulating the metabolism of propionate in M. smegmatis. Finally, along with Ms-Acs, we identified a candidate propionyl-CoA synthetase, Ms5404, as acetylated in whole-cell lysates. This work lays the foundation for studying the regulatory circuit of acetylation and deacetylation in the cellular context of mycobacteria

Tat–Dependent Translocation of an F420–Binding Protein of Mycobacterium tuberculosis

F420 is a unique cofactor present in a restricted range of microorganisms, including mycobacteria. It has been proposed that F420 has an important role in the oxidoreductive reactions of Mycobacterium tuberculosis, possibly associated with anaerobic survival and persistence. The protein encoded by Rv0132c has a predicted N–terminal signal sequence and is annotated as an F420–dependent glucose-6-phosphate dehydrogenase. Here we show that Rv0132c protein does not have the annotated activity. It does, however, co–purify with F420 during expression experiments in M. smegmatis. We also show that the Rv0132c–F420 complex is a substrate for the Tat pathway, which mediates translocation of the complex across the cytoplasmic membrane, where Rv0132c is anchored to the cell envelope. This is the first report of any F420–binding protein being a substrate for the Tat pathway and of the presence of F420 outside of the cytosol in any F420–producing microorganism. The Rv0132c protein and its Tat export sequence are essentially invariant in the Mycobacterium tuberculosis complex. Taken together, these results show that current understanding of F420 biology in mycobacteria should be expanded to include activities occurring in the extra-cytoplasmic cell envelope

The 33S(n,α)30Si cross section measurement at n-TOF-EAR2 (CERN) : From 0.01 eV to the resonance region

The 33S(n,α)30Si cross section measurement, using 10B(n,α) as reference, at the n-TOF Experimental Area 2 (EAR2) facility at CERN is presented. Data from 0.01 eV to 100 keV are provided and, for the first time, the cross section is measured in the range from 0.01 eV to 10 keV. These data may be used for a future evaluation of the cross section because present evaluations exhibit large discrepancies. The 33S(n,α)30Si reaction is of interest in medical physics because of its possible use as a cooperative target to boron in Neutron Capture Therapy (NCT)

Cross section measurements of 155,157Gd(n, γ) induced by thermal and epithermal neutrons

© SIF, Springer-Verlag GmbH Germany, part of Springer Nature 2019Neutron capture cross section measurements on 155Gd and 157Gd were performed using the time-of-flight technique at the n_TOF facility at CERN on isotopically enriched samples. The measurements were carried out in the n_TOF experimental area EAR1, at 185 m from the neutron source, with an array of 4 C6D6 liquid scintillation detectors. At a neutron kinetic energy of 0.0253 eV, capture cross sections of 62.2(2.2) and 239.8(8.4) kilobarn have been derived for 155Gd and 157Gd, respectively, with up to 6% deviation relative to values presently reported in nuclear data libraries, but consistent with those values within 1.6 standard deviations. A resonance shape analysis has been performed in the resolved resonance region up to 181 eV and 307 eV, respectively for 155Gd and 157Gd, where on average, resonance parameters have been found in good agreement with evaluations. Above these energies and up to 1 keV, the observed resonance-like structure of the cross section has been analysed and characterised. From a statistical analysis of the observed neutron resonances we deduced: neutron strength function of 2. 01 (28) × 10 - 4 and 2. 17 (41) × 10 - 4; average total radiative width of 106.8(14) meV and 101.1(20) meV and s-wave resonance spacing 1.6(2) eV and 4.8(5) eV for n + 155Gd and n + 157Gd systems, respectively.Peer reviewedFinal Accepted Versio

Characterization of the n-TOF EAR-2 neutron beam

The experimental area 2 (EAR-2) at CERNs neutron time-of-flight facility (n-TOF), which is operational since 2014, is designed and built as a short-distance complement to the experimental area 1 (EAR-1). The Parallel Plate Avalanche Counter (PPAC) monitor experiment was performed to characterize the beam prole and the shape of the neutron 'ux at EAR-2. The prompt γ-flash which is used for calibrating the time-of-flight at EAR-1 is not seen by PPAC at EAR-2, shedding light on the physical origin of this γ-flash

Measurement of the 240Pu(n,f) cross-section at the CERN n-TOF facility : First results from experimental area II (EAR-2)

The accurate knowledge of the neutron-induced fission cross-sections of actinides and other isotopes involved in the nuclear fuel cycle is essential for the design of advanced nuclear systems, such as Generation-IV nuclear reactors. Such experimental data can also provide the necessary feedback for the adjustment of nuclear model parameters used in the evaluation process, resulting in the further development of nuclear fission models. In the present work, the 240Pu(n,f) cross-section was measured at CERN's n-TOF facility relative to the well-known 235U(n,f) cross section, over a wide range of neutron energies, from meV to almost MeV, using the time-of-flight technique and a set-up based on Micromegas detectors. This measurement was the first experiment to be performed at n-TOF's new experimental area (EAR-2), which offers a significantly higher neutron flux compared to the already existing experimental area (EAR-1). Preliminary results as well as the experimental procedure, including a description of the facility and the data handling and analysis, are presented