2,117 research outputs found

    Microplastic abundance in beach sediments of the Kiel Fjord, Western Baltic Sea

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    We assessed the abundance of microplastics (0.2–5 mm) in drift line sediments from three sites in Kiel Fjord, Western Baltic Sea. The first site is intensively used by beach visitors, the second is in close proximity to a sewage plant and the third is polluted with large-sized plastic litter. Samples were split into three grain size classes (0.2–0.5, 0.5–1, 1–5 mm), washed with calcium chloride solution, and filtered at 0.2 mm. Filters were then visually inspected, and a total of 180 fragments was classified as microplastics, of which 39% were analyzed using Raman spectroscopy. At the site that is close to a sewage plant as well as at the site with intense beach use, 1.8 and 4.5 particles (fibers plus fragments) per kg of dry sediment were found, respectively, while particle abundances reached 30.2 per kg of dry sediment at the site with high litter loads. Our data suggest that the fragmentation of large plastic debris at site seems to be a relevant source for microplastics in Western Baltic Sea beach sediments

    Alcohols as a Means to Inhibit the Formation of Precipitates in Blends of Biodiesel and Fossil Diesel Fuel

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    The European diesel fuel specification limits the biodiesel content to 7 %. It is, however, desirable to increase the amount of renewables in the transport sector; therefore blending with a higher biogenic fuel content is of interest. Blending of fuels can lead to chemical reactions between fuel components and may result in undesired products. In detail, aged biodiesel from unsaturated FAME and fossil diesel fuels can form oligomers and precipitations with a maximum in the range of B10 to B20. Precursors are oligomers that can be separated from the biodiesel or the blends in an amount of up to 20 %. These oligomers seem to have potency for chemical reactions with fuel components or the engine oil. To prevent tentative problems in the fuel filter, the injecting system and the combustion process itself, the formation of oligomers should be disabled in blends. Alcohols have been proven and tested to dis-solve precipitations in the fuel. However, flash point problems occur, in case the alcohols have too low boiling points. In our tests, some alcohols could be identified to reach the demands of the diesel fuel standard EN 590. As acceptable monovalent alcohols, the longer-chained alcohols 1-octanol, 3-methyl-1-butanol (isoamyl alcohol) and 2-hexyldecan-1-ol were found. The blends with these alcohols both showed acceptable flashpoints according to DIN EN 590 and could prevent the occurrence of precipi-tates when added in a rather low concentration of about 6 to 8 %. Additionally, engine tests were carried out to monitor regulated and non-regulated emissions. The emissions of selected blends (B10+6OctOH, B10+8IsoamylOH, B10+8HexdecOH) were analyzed by using a single cylinder test engine (Farymann Diesel 18W, TIER 4, agricultural 5-mode test). All of these blends showed less NOx emissions than the pure B10 blend without addition of alcohol. For the CO, HC and PM emissions, no remarkable changes could be found. In the case of non-regulated emis-sions, no relevant changes were observed in carbonyl and PAH emissions, relative to the B10 blend without addition of alcohol. In the result, some blends from biodiesel, diesel fuel and alcohols tend to be appropriate to suppress chemical reactions in the fuel and probably in the engine oil. Further research is necessary to explain the chemical interactions that are responsible for the formation of oligomers and their reaction products. Not only chemical but physical bonds can play important roles and are in the focus of current research

    Comparative genome analysis and gene finding in Candida species using CGOB.

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    The Candida Gene Order Browser (CGOB) was developed as a tool to visualize and analyze synteny relationships in multiple Candida species, and to provide an accurate, manually curated set of orthologous Candida genes for evolutionary analyses. Here, we describe major improvements to CGOB. The underlying structure of the database has been changed significantly. Genomic features are now based directly on genome annotations rather than on protein sequences, which allows non-protein features such as centromere locations in Candida albicans and tRNA genes in all species to be included. The data set has been expanded to 13 species, including genomes of pathogens (C. albicans, C. parapsilosis, C. tropicalis, and C. orthopsilosis), and those of xylose-degrading species with important biotechnological applications (C. tenuis, Scheffersomyces stipitis, and Spathaspora passalidarum). Updated annotations of C. parapsilosis, C. dubliniensis, and Debaryomyces hansenii have been incorporated. We discovered more than 1,500 previously unannotated genes among the 13 genomes, ranging in size from 29 to 3,850 amino acids. Poorly conserved and rapidly evolving genes were also identified. Re-analysis of the mating type loci of the xylose degraders suggests that C. tenuis is heterothallic, whereas both Spa. passalidarum and S. stipitis are homothallic. As well as hosting the browser, the CGOB website (http://cgob.ucd.ie) gives direct access to all the underlying genome annotations, sequences, and curated orthology data

    Locally critical quantum phase transitions in strongly correlated metals

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    When a metal undergoes a continuous quantum phase transition, non-Fermi liquid behaviour arises near the critical point. It is standard to assume that all low-energy degrees of freedom induced by quantum criticality are spatially extended, corresponding to long-wavelength fluctuations of the order parameter. However, this picture has been contradicted by recent experiments on a prototype system: heavy fermion metals at a zero-temperature magnetic transition. In particular, neutron scattering from CeCu6x_{6-x}Aux_x has revealed anomalous dynamics at atomic length scales, leading to much debate as to the fate of the local moments in the quantum-critical regime. Here we report our theoretical finding of a locally critical quantum phase transition in a model of heavy fermions. The dynamics at the critical point are in agreement with experiment. We also argue that local criticality is a phenomenon of general relevance to strongly correlated metals, including doped Mott insulators.Comment: 20 pages, 3 figures; extended version, to appear in Natur

    Acupuncture in Patients with Diabetic Peripheral Neuropathy-Related Complaints: A Randomized Controlled Clinical Trial

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    Background: Diabetic polyneuropathy (DPN) is a common complication of diabetes, which presents with a loss of sensorimotor function or pain. This study assessed the effectiveness and safety of acupuncture as a treatment for DPN-related complaints. Methods: In this randomized controlled trial, patients with type II diabetes and symptoms of neuropathy in the lower limbs were included. A total of 12 acupuncture treatments were administered over 8 weeks. The waitlist control group received the same acupuncture treatment starting at week 16 (after baseline). Results: A total of 62 patients were randomized (acupuncture group n = 31; control group n = 31). The primary outcome was overall complaints, and it was reduced with a significant difference of 24.7 on a VAS (CI 95% 14.8;34.7, p < 0.001) between both groups in favor of acupuncture. Reductions were recorded for the secondary outcomes VAS pain, neuropathic pain symptom inventory (NPSI), emotional dimensions of pain, SF-12, and diabetic peripheral neuropathic pain impact (DPNPI) after the intervention and at the follow-ups in the acupuncture group. Adverse reactions were minor and transient. Conclusions: Acupuncture leads to a significant and lasting reduction in DPN-related complaints when compared to routine care and is well tolerated, with minor side effects

    Local fluctuations in quantum critical metals

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    We show that spatially local, yet low-energy, fluctuations can play an essential role in the physics of strongly correlated electron systems tuned to a quantum critical point. A detailed microscopic analysis of the Kondo lattice model is carried out within an extended dynamical mean-field approach. The correlation functions for the lattice model are calculated through a self-consistent Bose-Fermi Kondo problem, in which a local moment is coupled both to a fermionic bath and to a bosonic bath (a fluctuating magnetic field). A renormalization-group treatment of this impurity problem--perturbative in ϵ=1γ\epsilon=1-\gamma, where γ\gamma is an exponent characterizing the spectrum of the bosonic bath--shows that competition between the two couplings can drive the local-moment fluctuations critical. As a result, two distinct types of quantum critical point emerge in the Kondo lattice, one being of the usual spin-density-wave type, the other ``locally critical.'' Near the locally critical point, the dynamical spin susceptibility exhibits ω/T\omega/T scaling with a fractional exponent. While the spin-density-wave critical point is Gaussian, the locally critical point is an interacting fixed point at which long-wavelength and spatially local critical modes coexist. A Ginzburg-Landau description for the locally critical point is discussed. It is argued that these results are robust, that local criticality provides a natural description of the quantum critical behavior seen in a number of heavy-fermion metals, and that this picture may also be relevant to other strongly correlated metals.Comment: 20 pages, 12 figures; typos in figure 3 and in the main text corrected, version as publishe

    Protomers of Benzocaine: Solvent and Permittivity Dependence

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    The immediate environment of a molecule can have a profound influence on its properties. Benzocaine, the ethyl ester of para-aminobenzoic acid, which finds an application as a local anesthetic (LA), is found to adopt in its protonated form at least two populations of distinct structures in the gas phase and their relative intensities strongly depend on the properties of the solvent used in the electrospray ionization (ESI) process. Here we combine IR-vibrational spectroscopy with ion mobility-mass spectrometry (IM-MS) to yield gas-phase IR spectra of simultaneously m/z and drift-time resolved species of benzocaine. The results allow for an unambiguous identification of two protomeric species - the N- and O-protonated form. Density functional theory (DFT) calculations link these structures to the most stable solution and gas-phase structures, respectively, with the electric properties of the surrounding medium being the main determinant for the preferred protonation site. The fact that the N-protonated form of benzocaine can be found in the gas phase is owed to kinetic trapping of the solution phase structure during transfer into the experimental setup. These observations confirm earlier studies on similar molecules where N- and O-protonation has been suggested

    Zukunftsbild Hochschullehre 2025

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    Das Diskussionspapier zur Hochschullehre 2025 zeichnet sich methodisch durch seine partizipative Entstehung aus: In einem der HFDcon 2022 zeitlich vorgelagerten Prozess trafen sich 21 angemeldete Teilnehmer:innen aus dem deutschen Hoch- schulumfeld, um den Wandel der Hochschullehre für das Jahr 2025 zu skizzieren und Thesen für eine neue Denkkultur zu formu- lieren. In mehreren virtuellen Sitzungen wurden zunächst die Ziele des Papiers definiert, Themen geclustert und erste Forderungen ent- wickelt. Innerhalb der folgenden vier Wochen wurde dann – teils in Kleingruppen – kontrovers diskutiert, formuliert und überarbeitet, bis das Papier am 30. Juni 2022 in seiner ersten Fassung auf der Konferenz HFDcon 2022 vorgestellt wurde
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