Metabolic activity and symbiotic interactions of lactic acid bacteria and yeasts isolated from water kefir

Water kefir is a mildly sour and alcoholic drink fermented by a stable microbial multispecies community. With its high sugar content and low amino acid concentration water kefir medium represents a demanding habitat. In this ecological niche only well adapted microorganisms which are fit to the consortium are able to grow and mutually provide essential nutrients. The synergism between main representatives of water kefir yeasts and lactobacilli was studied in a co-culture model system. Co-cultivation of yeasts and lactobacilli in water kefir medium significantly increased cell yield of all interaction partners, delineating the interaction of these water kefir isolates as mutualism. The support of Zygotorulaspora (Z.) florentina was due to the acidification of the medium by the lactobacilli, whereas lactobacilli are improved in growth by the disposal of essential nutrients produced by yeasts. The trophic interaction between Lactobacillus (Lb.) hordei and yeasts is constituted by the release of amino acids and Vitamin B₆ from yeasts, whereas Lb. nagelii is supported in growth by their production of amino acids. The interaction of Z. florentina and Lb. nagelii was further examined to reveal that co-cultivation induced the yeast to release arginine, which was essential for Lb. nagelii.     

Digital shinrin-yoku: do nature experiences in virtual reality reduce stress and increase well-being as strongly as similar experiences in a physical forest?

Virtual Reality - Shinrin-yoku or forest bathing refers to a therapeutic, immersive nature experience that aids to improve well-being. The goal of the current research was to compare the effects of...     

Extending a brainiac prover to lambda-free higher-order logic

Decades of work have gone into developing efficient proof calculi, data structures, algorithms, and heuristics for first-order automatic theorem proving. Higher-order provers lag behind in terms of efficiency. Instead of developing a new higher-order prover from the ground up, we propose to start with the state-of-the-art superposition prover E and gradually enrich it with higher-order features. We explain how to extend the prover’s data structures, algorithms, and heuristics to \(\lambda \)-free higher-order logic, a formalism that supports partial application and applied variables. Our extension outperforms the traditional encoding and appears promising as a stepping stone toward full higher-order logic.

     

Countercurrent chromatography isolation of 11′-γ-tocomonoenol from pumpkin seed oil with detection of novel minor tocochromanols

A non-refined, organic pumpkin seed oil (PSO) was chosen for the isolation and structure verification of the rare vitamin E compound γ-tocomonoenol (γ-T1). Initial measurements indicated the presence of ~0.4 mg γ-T1 per 100 g PSO. Saponification of ~2 L of PSO, followed by repeated countercurrent chromatography (CCC) with the solvent system n-hexane/benzotrifluoride/acetonitrile (v/v/v) and silica gel column chromatography enabled the isolation of 6.8 mg γ-T1 with a purity of 96.0% according to gas chromatography with mass spectrometry (GC/MS) analysis. Structural analysis by ¹H nuclear magnetic resonance (NMR) spectroscopy and GC/MS of the γ-T1 isolate confirmed the presence of a double bond in C-11′-position (11′-γ-tocomonoenol). In addition, CCC fractionation enabled the detection of 18 different tocochromanols, many of which were reported for the first time in PSO. This unmatched variety included among others α-/γ-tocopherol, α-/γ-tocomonoenol, two α- and two γ-tocodienol isomers, α-/γ-tocotrienol as well as the rare 11′-β-tocomonoenol (β-T1) and δ-T1. Three uncommon tocochromanols were also detected whose origins and structure remained unclear.     

Emergence of Nontrivial Low-Energy Dirac Fermions in Antiferromagnetic EuCd2As2

Parity-time symmetry plays an essential role for the formation of Dirac states in Dirac semimetals. So far, all of the experimentally identified topologically nontrivial Dirac semimetals (DSMs) possess both parity and time reversal symmetry. The realization of magnetic topological DSMs remains a major issue in topological material research. Here, combining angle-resolved photoemission spectroscopy with density functional theory calculations, it is ascertained that band inversion induces a topologically nontrivial ground state in EuCd₂As₂. As a result, ideal magnetic Dirac fermions with simplest double cone structure near the Fermi level emerge in the antiferromagnetic (AFM) phase. The magnetic order breaks time reversal symmetry, but preserves inversion symmetry. The double degeneracy of the Dirac bands is protected by a combination of inversion, time-reversal, and an additional translation operation. Moreover, the calculations show that a deviation of the magnetic moments from the c-axis leads to the breaking of C3 rotation symmetry, and thus, a small bandgap opens at the Dirac point in the bulk. In this case, the system hosts a novel state containing three different types of topological insulator: axion insulator, AFM topological crystalline insulator (TCI), and higher order topological insulator. The results provide an enlarged platform for the quest of topological Dirac fermions in a magnetic system.     

Technical note: Evaluation of a sonographic overbagging edema scoring system for show cows: Comparison with visual inspection

Overbagged udders are commonly seen at dairy cow shows due to prolonged milking intervals. The aims of this study were to describe the prevalence of udder edema in dairy cows at shows as determined by sonography and to suggest a sonographic scoring system, which was evaluated for reproducibility and repeatability. At 4 highly competitive Swiss dairy cow shows, 319 cows of various breeds were examined. Sonographic scans—1 from each fore quarter and 1 from the rear, representing both hind quarters—were collected by 3 experienced veterinarians at defined positions predisposed to overbagging edema. Sonographic scans were scored with the aid of a newly suggested scoring system (score 0 = no edema, grade 1 = slight edema, grade 2 = moderate edema, grade 3 = severe edema). Further, 139 video sequences from behind while the cows were walking and the same number of photographs of the udder each from the left, right, and behind were selected. The photographs and video sequences were visually scored for different parameters as 0 = not present or 1 = present except for abduction, which was scored on a visual analog scale (0 = no abduction; 100 = maximal imaginable abduction). Visual scores were then compared with the sonographic scoring (Pearson's chi-squared). The prevalence of udder edema scores 1, 2, and 3 was 14.0, 6.5, and 2.3%, respectively. Interobserver reliability for objective sonographic scoring (κ = 0.815) and intraobserver agreement (κ = 0.90 and 0.85 for 2 different observers) was estimated as “almost perfect.” Interobserver agreements for visual parameters were κ = 0.40 or less except for teat shape (κ = 0.52). Classification of the videos resulted in better interobserver agreement; when rating hind limb abduction, Spearman correlation coefficient was 0.61, whereas κ = 0.61 for absence of udder movement. Udder movement and teat shape were significantly associated with the edema score. The higher inter- and intraobserver reliability of the sonographic edema scoring compared with the visual scoring system indicates that the newly suggested scoring system might be used in the future to objectively identify udder edema in cows at dairy shows.     

Geothermal Energy Potential of Active Northern Underground Mines: Designing a System Relying on Mine Water

Mine Water and the Environment - Mines in northern regions must heat underground workings, surface buildings, or process water due to frigid weather conditions. Mining companies commonly use fossil...     

Polyaluminum chloride with high Al30 content as removal agent for arsenic-contaminated well water

Polyaluminum chloride (PACl) is a well-established coagulant in water treatment with high removal efficiency for arsenic. A high content of Al₃₀ nanoclusters in PACl improves the removal efficiency over broader dosage and pH range. In this study we tested PACl with 75% Al₃₀ nanoclusters (PACl_Al30) for the treatment of arsenic-contaminated well water by laboratory batch experiments and field application in the geothermal area of Chalkidiki, Greece, and in the Pannonian Basin, Romania. The treatment efficiency was studied as a function of dosage and the nanoclusters’ protonation degree. Acid-base titration revealed increasing deprotonation of PACl_Al30 from pH 4.7 to the point of zero charge at pH 6.7. The most efficient removal of As(III) and As(V) coincided with optimal aggregation of the Al nanoclusters at pH 7-8, a common pH range for groundwater. The application of PACl_Al30 with an Al_tot concentration of 1-5 mM in laboratory batch experiments successfully lowered dissolved As(V) concentrations from 20 to 230 μg/L to less than 5 μg/L. Field tests confirmed laboratory results, and showed that the WHO threshold value of 10 μg/L was only slightly exceeded (10.8 μg/L) at initial concentrations as high as 2300 μg/L As(V). However, As(III) removal was less efficient (<40%), therefore oxidation will be crucial before coagulation with PACl_Al30. The presence of silica in the well water improved As(III) removal by typically 10%. This study revealed that the Al₃₀ nanoclusters are most efficient for the removal of As(V) from water resources at near-neutral pH.     

Sparse matrix operations on several multi-core architectures

This paper compares various contemporary multicore-based microprocessor architectures from different vendors with different memory interconnects regarding performance, speedup, and parallel efficiency. Sparse matrix decomposition is used as a benchmark application. The example matrix used in the experiments comes from an electrical engineering application, where numerical simulation of physical processes plays an important role in the design of industrial products.