bluuebunny/crossref_metadata_2025 huggingface dataset:
Conformational changes in Chikungunya virus E2 protein upon heparan sulfate receptor binding explain mechanism of E2–E1 dissociation during viral entry
Authors: Sahoo Bibekananda , Chowdary Tirumala Kumar
Published: June 2019

Receptor binding is the first step in viral cell entry. In enveloped virus cell entry, viral and host membrane fusion follows receptor binding. Viral surface receptor-binding protein associates with membrane fusion protein and masks its structure, to prevent pre-mature fusion activity. Dissociation of receptor-binding protein from fusion protein is an essential step before membrane fusion. Mechanism of receptor binding leading to dissociation of receptor binding and fusion protein is poorly understood in alphaviruses. Chikungunya virus (CHIKV), an alphavirus, re-emerged as a global pathogen in recent past. CHIKV surface envelope proteins, E2 and E1, function as receptor binding and fusion protein, respectively. Site of heparan sulfate (HS) receptor binding on E2–E1 heterodimer and its effect on E2–E1 heterodimer conformation is not known. Using molecular docking, we mapped HS binding to a positively charged pocket on E2 that is structurally conserved in alphaviruses. Based on our results from docking and sequence analysis, we identified a novel HS-binding sequence motif in E2. Purified E2 binds to heparin and HS specifically through charge interactions. Binding affinity of E2 to HS is comparable with other known HS–protein interactions (Kd ∼ 1.8 μM). Mutation of charged residues in the predicted HS-binding motif of E2 to alanine resulted in reduction of HS binding. Molecular dynamics (MD) simulations on E2, after docking HS, predicted allosteric domain movements. Fluorescence spectroscopy, far-UV circular dichroism spectroscopy, fluorescence resonance energy transfer experiments on HS-bound E2 corroborate our findings from MD simulations. We propose a mechanism where receptor-binding results in allosteric domain movements in E2, explaining E2–E1 dissociation.
Carbon cycling and interior evolution of water-covered plate tectonics and stagnant-lid planets
Authors: Höning Dennis , Tosi Nicola , Spohn Tilman
Published: June 2019

Aims. The long-term carbon cycle for planets with a surface entirely covered by oceans works differently from that of the present-day Earth because inefficient erosion leads to a strong dependence of the weathering rate on the rate of volcanism. In this paper, we investigate the long-term carbon cycle for these planets throughout their evolution.

Methods. We built box models of the long-term carbon cycle based on CO2 degassing, seafloor-weathering, metamorphic decarbonation, and ingassing and coupled them with thermal evolution models of plate tectonics and stagnant-lid planets.

Results. The assumed relationship between the seafloor-weathering rate and the atmospheric CO2 or the surface temperature strongly influences the climate evolution for both tectonic regimes. For a planet with plate tectonics, the atmospheric CO2 partial pressure is characterized by an equilibrium between ingassing and degassing and depends on the temperature gradient in subduction zones affecting the stability of carbonates. For a stagnant lid planet, partial melting and degassing are always accompanied by decarbonation, such that the combined carbon content of the crust and atmosphere increases with time. While the initial mantle temperature on planets with plate tectonics only affects the early evolution, it influences the evolution of the surface temperature of stagnant-lid planets for much longer.

Conclusions. For both tectonic regimes, mantle cooling results in a decreasing atmospheric CO2 partial pressure. For a planet with plate tectonics this is caused by an increasing fraction of subduction zones that avoid crustal decarbonation, and for stagnant-lid planets this is caused by an increasing decarbonation depth. This mechanism may partly compensate for the increase of the surface temperature due to increasing solar luminosity with time, and thereby contribute to keeping planets habitable in the long-term.
Period spacings of gravity modes in rapidly rotating magnetic stars
Authors: Prat V. , Mathis S. , Buysschaert B. , Van Beeck J. , Bowman D. M. , Aerts C. , Neiner C.
Published: June 2019

Context.Stellar magnetic fields are often invoked to explain the missing transport of angular momentum observed in models of stellar interiors. However, the properties of an internal magnetic field and the consequences of its presence on stellar evolution are largely unknown.

Aims.We study the effect of an axisymmetric internal magnetic field on the frequency of gravity modes in rapidly rotating stars to check whether gravity modes can be used to detect and probe such a field.

Methods.Rotation is taken into account using the traditional approximation of rotation and the effect of the magnetic field is computed using a perturbative approach. As a proof of concept, we compute frequency shifts due to a mixed (i.e. with both poloidal and toroidal components) fossil magnetic field for a representative model of a known magnetic, rapidly rotating, slowly pulsating B-type star: HD 43317.

Results.We find that frequency shifts induced by the magnetic field scale with the square of its amplitude. A magnetic field with a near-core strength of the order of 150 kG (which is consistent with the observed surface field strength of the order of 1 kG) leads to signatures that are detectable in period spacings for high-radial-order gravity modes.

Conclusions.The predicted frequency shifts can be used to constrain internal magnetic fields and offer the potential for a significant step forward in our interpretation of the observed structure of gravity-mode period spacing patterns in rapidly rotating stars.
The essential elements of dust evolution
Authors: Jones A. P. , Ysard N.
Published: June 2019

Context. There remain many open questions relating to the depletion of elements into dust, e.g., exactly how are C and O incorporated into dust in dense clouds and, in particular, what drives the disappearance of oxygen in the denser interstellar medium?

Aims. This work is, in part, an attempt to explain the apparently anomalous incorporation of O atoms into dust in dense clouds.

Methods. We re-visit the question of the depletion of the elements incorporated into the carbonaceous component of interstellar dust, i.e., C, H, O, N and S, in the light of recent analyses of the organics in comets, meteorites and interplanetary dust particles.

Results. We find that oxygen could be combined with ≈10–20 % of the carbon in the dust in dense regions in the form of a difficult to observe, organic carbonate, (−O−O>C =O), which could explain the unaccounted for 170–255 ppm oxygen depletion.

Conclusions. We conclude that, while C, O and N atoms are depleted into an amorphous a-C:H:O:N phase, we posit that a significant fraction of C and O atoms could be sequestered into an organic carbonate, which provides a viable solution to the oxygen depletion problem. Further, the thermal or photolytic decomposition of this carbonate may have a bearing on the formation of CO2 in the ISM.
Summation Calculations for Reactor Antineutrino Spectra, Decay Heat and Delayed Neutron Fractions Involving New TAGS Data and Evaluated Databases
Authors: Estienne M. , Fallot M. , Giot L. , Guadilla-Gomez V. , Le Meur L. , Porta A. , Algora A. , Taìn J. -L. , Briz J. A. , Agramunt J. , Äystö J. , Cormon S. , Cucoanes A. , Eronen T. , Fraile L. M. , Ganogliu E. , Gelletly W. , Gorelov D. , Hakala J. , Jokinen A. , Jordan M. D. , Kankainen A. , Kolhinen V. S. , Koponen J. , Lebois M. , Martinez T. , Monserrate M. , Montaner-Pizá A. , Moore I. , Nácher E. , Orrigo S. E. A. , Penttilä H. , Pohjalainen I. , Reinikainen J. , Reponen M. , Rinta-Antila S. , Rytkönen K. , Rubio B. , Shiba T. , Sonnenschein V. , Sonzogni A. A. , Valencia E. , Vedia V. , Voss A. , Weber C. , Wilson J. N. , Zakari-Issoufou A. -A.
Published: June 2019

Three observables of interest for present and future reactors depend on the β decay properties of the fission products: antineutrinos from reactors, the reactor decay heat and delayed neutron emission. In these proceedings, we present new results from summation calculations of the first two quantities quoted above, performed with evolved independent yields coupled with fission product decay data, from various nuclear data bases or models. New TAGS results from the latest experiment of the TAGS collaboration at the JYFL facility of Jyväskylä will be displayed as well as their impact on the antineutrino spectra and the decay heat associated to fission pulses of the main actinides.
Energy Dependence of Delayed-Neutron Data
Authors: Foligno Daniela , Leconte Pierre
Published: June 2019

Delayed neutron data is essential in inherent reactor safety and in reactor control. The different sources and results of delayed neutron data in international databases will be discussed. In addition to direct measurement, these data can be obtained by calculations based on fission yields (FY) and radioactive decay data (RDD). Unfortunately, FY are only given at three energies in the European library JEFF. This works proposes to use GEF-FY energy dependence to extrapolate JEFF-FY at other energies. The preliminary results highlight that GEF energy dependence is not always suitable to reproduce experimental values and that more measurements are needed at high energies.
Study of the photon strength functions and level density in the gamma decay of the n + 234U reaction
Authors: Moreno-Soto J. , Berthoumieux E , Dupont E , Gunsing F , Serot O , Litaize O , Diakaki M , Chebboubi A , Dridi W , Valenta S , Krtiˇcka M. , Aberle O , Alcayne V , Andrzejewski J , Audouin L , Bécares V. , Babiano-Suarez V. , Bacak M , Barbagallo M , Benedikt Th , Bennett S , Billowes J , Bosnar D , Brown A , Busso M , Caamaño M. , Caballero-Ontanaya L. , Calviño F. , Calviani M , Cano-Ott D. , Casanovas A , Cerutti F , Chiaveri E , Colonna N , Cortés G. , Cortés-Giraldo M. A. , Cosentino L , Cristallo S , Damone L. A , Davies P. J , Dietz M , Domingo-Pardo C. , Dressler R , Ducasse Q , Durán I. , Eleme Z , Fernández-Domínguez B. , Ferrari A , Finocchiaro P , Furman V , Göbel K. , Gawlik A , Gilardoni S , Gonçalves I. F. , González-Romero E. , Guerrero C , Heinitz S , Heyse J , Jenkins D. G , Junghans A , Käppeler F. , Kadi Y , Kimura A , Knapova I , Kokkoris M , Kopatch Y , Kurtulgil D , Ladarescu I , Lederer-Woods C. , Lonsdale S. J , Macina D , Manna A , Martínez T. , Masi A , Massimi C , Mastinu P , Mastromarco M , Maugeri E. A , Mazzone A , Mendoza E , Mengoni A , Michalopoulou V , Milazzo P. M , Mingrone F , Musumarra A , Negret A , Ogállar F. , Oprea A , Patronis N , Pavlik A , Perkowski J , Persanti L , Petrone C , Pirovano E , Porras I , Praena J , Quesada J. M , Ramos-Doval D. , Rauscher T , Reifarth R , Rochman D , Sabaté-Gilarte M. , Saxena A , Schillebeeckx P , Schumann D , Sekhar A , Simone S , Smith A. G , Sosnin N. V , Sprung P , Stamatopoulos A , Tagliente G , Tain J. L , Tarifeño-Saldivia A. , Tassan-Got L. , Tsinganis A , Ulrich J , Urlass S , Vannini G , Variale V , Vaz P , Ventura A , Vescovi D , Vlachoudis V , Vlastou R , Wallner A , Woods P. J , Wright T , Žugec P. ,   and the n_TOF Collaboration
Published: June 2019

The accurate calculations of neutron-induced reaction cross sections are relevant for many nuclear applications. The photon strength functions and nuclear level densities are essential inputs for such calculations. These quantities for 235U are studied using the measurement of the gamma de-excitation cascades in radiative capture on 234U with the Total Absorption Calorimeter at n_TOF at CERN. This segmented 4π gamma calorimeter is designed to detect gamma rays emitted from the nucleus with high efficiency. This experiment provides information on gamma multiplicity and gamma spectra that can be compared with numerical simulations. The code DICEBOXC is used to simulate the gamma cascades while GEANT4 is used for the simulation of the interaction of these gammas with the TAC materials. Available models and their parameters are being tested using the present data. Some preliminary results of this ongoing study are presented and discussed.
High-resolution evaluation of the U5(n,f) cross section from 3 keV to 30 keV
Authors: Duran I. , Paradela C. , Caamaño M. , Cabanelas P. , Tassan-Got L. , Audouin L.
Published: June 2019

235U neutron-induced fission cross-section is commonly used as reference for determining other isotope fission cross-section. However, below 150 keV this cross section is only included as Standard at the thermal point and recently its integral value between 7.8 eV and 11 eV [1]. The resolved resonance region, spanning up to 2.25 keV, has been reevaluated with high resolution in the last ENDF/B-VIII release [2] and a SAMMY resonance analysis was done by L. Leal et al. [3] including the CERN-nTOF experimental work of Paradela el al. [4] up to 10 keV, taken into account the IAEA Reference file.

In this work the 235U(n,f) low-background and high-resolution experimental data obtained at the CERN-nTOF facility is combined with previous high-resolution experimental data, in order to produce a very fine grid dataset with normalisation to the IAEA Reference file. The extremelyhigh energy calibration required to reproduce the resonance sharp profiles is based on the nTOF DAQ system with a resolution below 0.1% with reference to the 8.78 eV resonance and to the sharp Al(n,g) capture dip at 5.904 keV.

The comparison of the so-evaluated profile with the experimental data and with the evaluated ones will be discussed.
An Experimental Programme optimized with Uncertainty Propagation: PETALE in the CROCUS Reactor
Authors: Lamirand Vincent , Laureau Axel , Rochman Dimitri , Perret Gregory , Gruel Adrien , Leconte Pierre , Blaise Patrick , Pautz Andreas
Published: June 2019

The PETALE experimental programme in the CROCUS reactor at EPFL intends to contribute to the validation and improvement of neutron nuclear data in the MeV energy range for stainless steel, particularly in the prospect of heavy reflector elements of pressurized water reactors. It mainly consists of several transmission experiments: first, through metallic sheets of nuclear-grade stainless steel interleaved with dosimeter foils, and, successively, through its elemental components of interest – iron, nickel, and chromium. The present article describes the study for optimizing the response of the dosimetry experiments to the nuclear data of interest.
Neutron inelastic scattering of 232Th: measurements and beyond
Authors: Party Eliot. , Borcea Catalin. , Dessagne Philippe. , Doligez Xavier. , Henning Grégoire. , Kerveno Maëlle. , Negret Alexandru. , Nyman Markus. , Olacel Adina. , Plompen Arjan.
Published: June 2019

Gamma production cross sections have been obtained for 81 transitions in 232Th from (n,n’γ), 11 in 231Th from (n,2nγ) and 7 in 230Th from (n,3nγ) reactions using prompt gamma spectroscopy. Incident neutron energies were determined using the neutron time-of-flight technique. Sources of uncertainty have been examined and their correlations have been computed. Total uncertainty on cross sections ranges from 4 to 20%. Obtained cross sections are in agreement with prior experiments, but are not well reproduced by the TALYS 1.8 reaction code using default parameters. During analysis, discrepancies between our findings and the Evaluated Nuclear Structure Data File (ENSDF) were noted. Future work related to the present experiment includes: improving theoretical models, quantifying the influence of the 232Th inelastic neutron cross section on reactor core parameters, and conducting additional measurements.
Influence of nuclear data parameters on integral experiment assimilation using Cook’s distance
Authors: Kumar D. , Alam S. B. , Sjöstrand H. , Palau J. M. , De Saint Jean C.
Published: June 2019

Nuclear data used in designing of various nuclear applications (e.g., core design of reactors) is improved by using integral experiments. To utilize the past critical experimental data to the reactor design work, a typical procedure for the nuclear data adjustment is based on the Bayesian theory (least-square technique or Monte-Carlo). In this method, the nuclear data parameters are optimized by the inclusion of the experimental information using a Bayesian inference. The selection of integral experiments is based on the availability of well-documented specifications and experimental data. Data points with large uncertainties or large residuals (outliers) may affect the accuracy of the adjustment. Hence, in the adjustment process, it is very important to study the influence of experiments as well as of the prior nuclear data on the adjusted results. In this work, the influence of each individual reaction (related to nuclear data) is analyzed using the concept of Cook’s distance. First, JEZEBEL (Pu239, Pu240 and Pu241) integral experiment is considered for data assimilation and then the transposition of results on ASTRID fast reactor concept is discussed.
Examples of Monte Carlo techniques applied for nuclear data uncertainty propagation
Authors: Cabellos Oscar , Fiorito Luca
Published: June 2019

The aim of this work is to review different Monte Carlo techniques used to propagate nuclear data uncertainties. Firstly, we introduced Monte Carlo technique applied for Uncertainty Quantification studies in safety calculations of large scale systems. As an example, the impact of nuclear data uncertainty of JEFF-3.3 235U, 238U and 239Pu is demonstrated for the main design parameters of a typical 3-loop PWR Westinghouse unit. Secondly, the Bayesian Monte Carlo technique for data adjustment is presented. An example for 235U adjustment using criticality and shielding integral benchmarks shows the importance of performing joint adjustment based on different set of integral benchmarks.
Die endoskopische Karpaltunnelspaltung im monoportalen Verfahren
Authors: Hessenauer Maximilian Emanuel Thomas , Horch Raymund E.
Published: June 2019

Das Karpaltunnelsyndrom stellt eines der häufigsten Beschwerdebilder in der Handchirurgie dar. Therapie der Wahl ist beim neurophysiologisch gesicherten Karpaltunnelsyndrom die operative Spaltung des Retinaculum musculorum flexorum. Die minimalinvasive endoskopische Karpaltunnelspaltung kann eine verbesserte Rekonvaleszenz bei gleichzeitig hoher Patientensicherheit gegenüber klassischen offenen Verfahren vorweisen. In der vorliegenden Videopublikation stellen wir das Operationsverfahren zur Karpaltunnelspaltung im monoportalen endoskopischen Vorgehen dar. Zudem berichten wir unsere Therapieerfahrungen in über 800 Fällen.
Kinder sollen mitentscheiden
Authors: Ufelmann Marina
Published: June 2019

Wenn eine Bezugsperson eines Kindes auf der Intensivstation liegt, sind Eltern
oft überfordert. Um das Kind zu schützen, werden Informationen vorenthalten und
Besuche verweigert. Aber ist das immer die beste Entscheidung? Haben Besuche auf
der Intensivstation wirklich negative Auswirkungen auf Kinder? Und was kann man
tun, damit eventuelle erschreckende Eindrücke keine negativen Erinnerungen
hinterlassen?
Halt geben oder festhalten?
Authors: Lanz Brigitte Wenger
Published: June 2019

Wie lassen sich Diagnostik und Therapien an Kindern möglichst bequem und angenehm
gestalten, auch wenn die Kinder dabei festgehalten werden müssen? Eine
Möglichkeit ist die sogenannte Comfort-Positionierung, die unter anderem am
Inselspital Bern in der Schweiz bereits seit 2014 Anwendung findet – und das mit
großem Erfolg.
Ablative Verfahren in der Therapie von Lebermetastasen
Authors: Schnitzbauer Andreas , Bechstein Wolf Otto , Vogl Thomas
Published: June 2019

Wenn keine extrahepatischen Metastasen vorliegen, kann ein verbessertes Überleben mit chirurgischen und interventionellen Techniken erreicht werden. Interventionelle Techniken sind entweder definiert als perkutane oder intraoperative Laparoskopie bzw. die Anwendung von thermischer Ablation. In diesem Review konzentrieren wir uns hierbei auf die beiden etablierten Techniken der Radiofrequenzablation (RFA) und der Mikrowellenablation (MWA) zur Therapie von kolorektalen Lebermetastasen. Diese beiden Techniken erlauben eine sichere Ablation von Metastasen bis zu 3 cm Größe und haben eine niedrige Komplikationsrate. In aktuellen Leitlinien haben beide Therapien ihren Stellenwert. Im Falle von schwierig zu resezierenden Metastasen stellen sie eine gute Alternative dar. Weiterhin können sie in Kombination mit Chirurgie eingesetzt werden, um das chirurgische Trauma zu reduzieren. Bei Rezidivmetastasen kann die Durchführung einer Intervention aufgrund des operativen Traumas niedrigere Morbidität für den Patienten bedeuten. Darüber hinaus sind die interventionellen Verfahren in Kombination mit einer systemischen Therapie der alleinigen Chemotherapie überlegen.
Röntgenstrahlenexposition in der Handchirurgie durch den
OrthoScan Mini-C-Arm: eine 1-Jahres Fallserie
Authors: Hohendorff Bernd , Sauer Henning , Biber Franz , Franke Jörg , Müller Lars Peter , Ries Christian
Published: June 2019

Hintergrund Mobile Röntgenbildgebungssysteme sind im Operationssaal
Standard. In der Handchirurgie haben sich Mini-C-Arme durchgesetzt. Leider wird
die Strahlenexposition durch einen Mini-C-Arm häufig verharmlost.

Methoden Während eines Jahres wurde die intraoperative Strahlenexposition
durch den OrthoScan High Definition Mini-C-Arm mit Flachbilddetektor bei allen
Operationen an der Hand und am Handgelenk, die von drei erfahrenen Handchirurgen
durchgeführt wurden, mittels Kopfband- und Fingerringdosimetern gemessen.

Ergebnisse Insgesamt wurden 213 Patienten unter Verwendung des OrthoScan
High Definition Mini-C-Arm operativ behandelt. Die von allen drei Handchirurgen
applizierte Gesamtstrahlendosis innerhalb von 12 Monaten betrug 9033,39 mGy bei
einer Gesamtstrahlungszeit von 376:38 min. Bei einem Operateur wurde während
eines Monats an beiden Fingerringdosimetern eine Strahlenexposition von jeweils
2,0 mSv nachgewiesen. Bei allen anderen Dosimetern lag die monatliche
Strahlenexposition unterhalb der Nachweisgrenze von < 0,3 mSv.

Schlussfolgerung Die Grenzwerte der jährlichen Strahlenexposition für
allgemein und beruflich exponierte Personen von 50 mSv für die Hand und 20 mSv
für die Augenlinse werden bei rund 100 Operationen/Operateur/Jahr unter
Verwendung des OrthoScan Mini-C-Arms nicht erreicht. Erst ab einer
Röntgenstrahlendosis von ca. 800–1000 mGy/Monat ist die Strahlenexposition mit
einem Fingerringdosimeter (Messbereich von 0,3 mSv–10 Sv) beim Handchirurgen
nachweisbar. Auf Grund des potentiellen Gesundheitsrisikos infolge einer
stochastischen Strahlenwirkung sollten alle möglichen Schutz- und
Verhaltensmaßnahmen konsequent befolgt werden.
Tricyanomethane and its Salts with Nitrogen Bases: A Correction of Sixteen Reports
Authors: Banert Klaus , Hagedorn Manfred
Published: June 2019

A series of 16 articles, dealing with formation of tricyanomethanide salts from nitrogen bases (amines) and tricyanomethane, turned out to be wrong because no tricyanomethane or similar compounds are used and no tricyanomethanide salts are prepared. This statement is based mainly on the recently published spectroscopic data and depicted spectra, which are completely incompatible with the claimed structures. Some of the tricyanomethanide salts are now synthesized from nitrogen heterocycles and tricyanomethane or other precursors. The corresponding products show plausible spectroscopic data and physical properties, which are entirely different to those previously reported.
Immunomodulatory Second-Line Therapies for Immune Thrombocytopenia
Authors: Lambert Michele P.
Published: June 2019

Management of immune thrombocytopenia (ITP) is complex requiring communication between patients and caregivers to establish a mutual understanding of the impact of the patient's disease on quality of life, the current symptoms and risk of morbidity/mortality and the goals of therapy. The currently available second-line therapies for ITP provide potential for management of thrombocytopenia and bleeding symptoms with medical therapy or surgical intervention potentially offering long-term remission. All therapies are associated with potential side effects and necessary monitoring or modifications/risks and careful discussion of these is necessary to determine the optimal therapy for each patient. This review covers second-line therapies for ITP and discusses the currently available information on immunomodulatory second-line treatments for ITP.
Oxidative DNA Damage and NOX4 Levels in Children with Undescended Testes
Authors: Avci Veli , Ayengin Kemal , Alp Hamit Hakan
Published: June 2019

Background Undescended testis (UDT) is a common urological disorder. Patients with UDT have a risk of malignancy and infertility. The development of these conditions may be due to oxidative stress mediated by reactive oxygen species. The aim of this study was to investigate the relationship between these parameters by detecting oxidative DNA damage (8-hydroxy 2 deoxyguanosine/106 deoxyguanosine), ischemia-modified albumin (IMA), malondialdehyde (MDA), and nicotinamide adenine dinucleotide phosphate oxidase 4 (NOX4) levels in children with UDT and healthy control group.

Materials and Methods The blood samples were obtained from 30 patients with UDT and 40 healthy male subjects. The levels of oxidative DNA damage were detected by high-pressure liquid chromatography method. We used commercially available kits that use enzyme-linked immunosorbent assay method to measure IMA, MDA, and NOX4 levels.

Results The levels of MDA, IMA, NOX4, and oxidative DNA damage in children with UDT were statistically significantly higher than control group. In addition, we found that the levels of NOX4, IMA, and oxidative DNA damage after 12 months of age was significantly higher than before 12 months of age.

Conclusion We identified increased lipid peroxidation, oxidative DNA damage, IMA, and NOX4 levels in children with UDT. Delay in the treatment of UDT may cause oxidative damage. That is why, according to us the antioxidant treatment may be beneficial in children with UDT.
Schrödinger operators with distributional potentials and boundary conditions dependent on the eigenvalue parameter
Authors: Guliyev Namig J.
Published: June 2019

We study various direct and inverse spectral problems for the one-dimensional Schrödinger equation with distributional potential and boundary conditions containing the eigenvalue parameter.
Laser-induced transverse voltage in (111)-oriented TiO1+δ epitaxial thin films with cubic structure
Authors: Fan Yunjie , Zhang Chao , Liu Xiang , Ma Chao , Zhou Xiaoguo , Li Yukun , Yin Yuewei , Li Xiaoguang
Published: June 2019

The laser-induced transverse voltage (LITV) was investigated systematically in (111)-oriented cubic TiO1+δ (1.08 ≤ 1 + δ ≤ 1.28) thin films grown on nontilted (0001)-oriented α-Al2O3 substrates. Utilizing the anisotropy between [001] and [110] directions, a feasible LITV measuring configuration was designed, and the peak voltage Up at room temperature reaches 0.92 V for the sample TiO1.08 irradiated by a laser with a wavelength of ∼248 nm and an energy density of ∼10 mJ/cm2. Both the voltage amplitude and the sensitivity of LITV decrease with the increasing oxygen content, probably due to the enhancement of disorder strength and the reduction of density of electronic states near the Fermi level. The Up value of the TiO1.08 film rises to 1.22 V upon increasing temperature to 450 K and then decreases upon further increasing the temperature. The LITV variations at different wavelengths indicate that the LITV should mainly come from a transverse thermoelectric effect when the photon energy is lower than the bandgap but may contain a contribution from a transverse photovoltaic effect when the photon energy is larger than the bandgap. These results provide considerable insight into LITV and offer a feasible method to explore more LITV materials.
Automatic basis-set adaptation in projection-based embedding
Authors: Bensberg Moritz , Neugebauer Johannes
Published: June 2019

Projection-based embedding (PbE) is an exact embedding method within density-functional theory (DFT) that has received increasing attention in recent years. Several different variants have been described in the literature, but no systematic comparison has been presented so far. The truncation of the basis is critical for the efficiency of this class of approaches. Here, we employ a basis-set truncation scheme previously used for level-shift embedding in a top-down fashion, and we present an own basis-set extension scheme for bottom-up type PbE. We compare its accuracy for the level-shift technique [Manby et al., J. Chem. Theory Comput. 8, 2564–2568 (2012)] and an empirically corrected variant, the external-orthogonality approach by Khait and Hoffmann [Annu. Rep. Comput. Chem. 8, 53–70 (2012)] and the approach based on the Huzinaga equation transferred to the DFT context [Hégely et al., J. Chem. Phys. 145, 064107 (2016)]. Concerning the reproduction in total energies, we show that the Huzinaga method yields the most stable results concerning a basis-set truncation in top-down embedding. For the practically more relevant calculation of energy differences, the efficient level-shift technique yields very promising results due to error cancellation. In bottom-up embedding, we observe convergence issues in cases where constraints in the Lagrange formalism cannot be fulfilled due to basis-set incompleteness.
Computationally efficient locally linearized constitutive model for magnetostrictive materials
Authors: Wahi Sajan K. , Kumar Manik , Santapuri Sushma , Dapino Marcelo J.
Published: June 2019

This paper presents a computationally efficient constitutive model for magnetostrictive materials. High computational efficiency is achieved through the use of local linearization (about easy axes) and discrete energy-averaging techniques. The model is applied to iron-gallium alloys (Galfenol) and tested for different magnetic field orientations relative to the easy axes. It is observed that the model accurately predicts both sensing and actuation characteristics while reducing the computation time by a large factor (>1000 times) when compared to the nonlinear energy minimization models. Furthermore, the average error observed in λ–H and B–H curves is less than 3.5% with the error increasing at magnetic field orientations farther from easy axes, particularly at large magnetic field values. Finally, the model is integrated with a finite element framework to predict the response of a Galfenol rod transducer system, and parametric studies are performed for different current and prestress conditions to optimize the device performance.
Closed-cycle, low-vibration 4 K cryostat for ion traps and other applications
Authors: Micke P. , Stark J. , King S. A. , Leopold T. , Pfeifer T. , Schmöger L. , Schwarz M. , Spieß L. J. , Schmidt P. O. , Crespo López-Urrutia J. R.
Published: June 2019

In vacuo cryogenic environments are ideal for applications requiring both low temperatures and extremely low particle densities. This enables reaching long storage and coherence times, for example, in ion traps, essential requirements for experiments with highly charged ions, quantum computation, and optical clocks. We have developed a novel cryostat continuously refrigerated with a pulse-tube cryocooler and providing the lowest vibration level reported for such a closed-cycle system with 1 W cooling power for a <5 K experiment. A decoupling system suppresses vibrations from the cryocooler by three orders of magnitude down to a level of 10 nm peak amplitudes in the horizontal plane. Heat loads of about 40 W (at 45 K) and 1 W (at 4 K) are transferred from an experimental chamber, mounted on an optical table, to the cryocooler through a vacuum-insulated massive 120 kg inertial copper pendulum. The 1.4 m long pendulum allows installation of the cryocooler in a separate, acoustically isolated machine room. At the experimental chamber, we measured the residual vibrations using an interferometric setup. The positioning of the 4 K elements is reproduced to better than a few micrometer after a full thermal cycle to room temperature. Extreme high vacuum on the 10−15 mbar level is achieved. In collaboration with the Max-Planck-Institut für Kernphysik, such a setup is now in operation at the Physikalisch-Technische Bundesanstalt for a next-generation optical clock experiment using highly charged ions.
Quantum interference of three dimensional plasmon excitations
Authors: Akbari-Moghanjoughi M.
Published: June 2019

In this paper, the quantum interference of plasmon excitations in the presence of charges or multipolar sources/sinks is investigated. The effective Schrödinger-Poisson system for dynamical description of the arbitrary degenerate fermi gas is reduced to a set of coupled linear pseudoforce system, and it is shown that this system admits a general multipolar solution in the 3D Cartesian coordinate. The obtained solution is then used to study well-known problems such as the double and quadruple charge interference effects. The double source interference produces patterns quite reminiscent of that of the double slit interference with the corresponding matter-wavelength matching that of the de Broglie wavelength of the electrons. It is found that the collective electrostatic interactions of quantum electron gas leads to the electrostatic energy depletion around the pole which causes electrostatic polar binding in the electron fluid. The later effect which has also been previously reported in some research seems to be an appropriate description of attractive metallic bindings. The current model is then extended to electronic interference effects in a crystal lattice with the quasiperiodic electronic states. The periodic arrangement of ionic cores in a crystal is shown to produce different density and electrostatic potential patterns for given energy eigenvalues of the fermi gas. Moreover, a generalized expression is obtained for electron probability current in the Schrödinger-Poisson model. The current model may provide a better platform for studying the quantum interference phenomenon in complex environments such as nanocompounds and plasmonic crystals.
Linear magnetoresistance in Cr-doped Bi2Se3 thin film
Authors: Ma Xiao Rong , Zhang Xing Hua , Wang Wen Jie , Gao Kuang Hong
Published: June 2019

This paper reports the magnetotransport property of a Cr-doped Bi2Se3 thin film. A linear magnetoresistance (MR) is observed in a high field region, while the weak antilocalization effect appears up near zero magnetic fields below 15 K, and it is transformed into a positive parabolic MR at high temperatures. It is found that the slope of the observed linear MR is proportional to the Hall mobility. Meanwhile, a crossover field from the parabolic MR to the linear MR is proportional to the inverse Hall mobility. These indicate that the observed linear MR can be explained by the classical mechanism. Most importantly, we find that the observed linear MR is suppressed with increasing time when the film is sealed in vacuum after growth. This indicates that the observed linear MR does not originate from a two-dimensional electron gas formed on the film surface. It is found that the observed linear MR is likely to arise from the bulk state.
Thermal transport in molecular beam epitaxy grown Si1 − xGex alloy films with a full spectrum of composition (x = 0–1)
Authors: Wang Yu-Sheng , Liu Zheng-Chang , Ye Jia-Jia , Zhang Wang-Wei , Gu Yu , Yan Xue-Jun , Lu Ming-Hui , Li Deyu , Lu Hong , Chen Yan-Feng
Published: June 2019

The thermal properties of Si1 – xGex alloys are important for two major reasons: one is their applications in high-temperature thermoelectrics and the other is the increasing heat dissipation demand for high power density devices. However, the large lattice mismatch between silicon and germanium leads to tremendous difficulties to obtain high-quality Si1 – xGex thin films, especially when x > 0.5. In this study, we obtained a series of high crystalline quality Si1 – xGex thin films with x covering all the way from 0 to 1 on Si substrates by molecular beam epitaxy. The out-of-plane thermal conductivities of these Si1 – xGex films were measured by the time-domain thermoreflectance approach. Results show that while the thermal conductivity can vary significantly with composition, it only changes marginally in the temperature range of 100 K–300 K for a specific Ge content x. A theoretical analysis indicates that alloy and boundary scatterings are the dominant mechanisms for the thermal transport in these Si1 – xGex (x = 0–1) alloy films.
Point defects in group III nitrides: A comparative first-principles study
Authors: Gao Yinlu , Sun Dan , Jiang Xue , Zhao Jijun
Published: June 2019

One of the main challenges in the development of wide bandgap semiconductor devices is to understand the behavior of defects and avoid their harm. Using density-functional theory calculations with hybrid functional, we systematically investigated the neutral and charged native point defects (vacancy, interstitial, and antisite defect) in GaN, AlN, and InN crystals in terms of local geometry relaxation, formation energies, and electronic and diffusion properties. By comparing the defect configuration and transition levels as a function of the Fermi level, we show that Ga interstitial (Gaoc, Gate) in GaN, N vacancy (VN), N interstitial (Ni), In antisite (InN), and In interstitial (Inte, Inoc) in InN can exist stably only in the positive charge states with donor level and VIn is stable in the neutral state, while the other defects exhibit both donor and acceptor behavior. Among them, the most stable defects are identified as VN for p-type nitrides and VGa, VAl for n-type nitrides. These results, providing a mechanism for self-compensation effects, explain the reduced doping efficiencies for both n-type and p-type nitrides due to defects. Moreover, it is also demonstrated that N interstitial diffuses faster than vacancy, which are mainly responsible for the low concentration of N interstitials and N-based defect complexes produced in nitrides. Significantly, the trends of formation energy, transition level, and migration barrier of nitrides are also consistent with their intrinsic atomic size and bandgap. Our study is important for the identification and control of point defects in nitrides, which have a profound impact on device performance and reliability.
A Bayesian approach for identification of ice Ih, ice Ic, high density, and low density liquid water with a torsional order parameter
Authors: Matsumoto Masakazu , Yagasaki Takuma , Tanaka Hideki
Published: June 2019

An order parameter is proposed to classify the local structures of liquid and solid water. The order parameter, which is calculated from the O–O–O–O dihedral angles, can distinguish ice Ih, ice Ic, high density, and low density liquid water. Three coloring schemes are proposed to visualize each of the coexisting phases in a system using the order parameter on the basis of Bayesian decision theory. The schemes are applied to a molecular dynamics trajectory in which ice nucleation occurs following spontaneous liquid-liquid separation in the deeply supercooled region as a demonstration.
Addition of SU(3) generators and its singlet Hilbert space
Authors: Anishetty Ramesh , Sreeraj T. P.
Published: June 2019

We construct the singlet Hilbert space associated with addition of SU(3) generators. This corresponds to the solution of Gauss law in lattice QCD. The normalized basis states are explicitly constructed using Schwinger bosons. Furthermore, we compute the action of basic singlet operators on these basis states.
Multi-state local complete active space second-order perturbation theory using pair natural orbitals (PNO-MS-CASPT2)
Authors: Kats Daniel , Werner Hans-Joachim
Published: June 2019

A multistate complete active space second-order perturbation theory (CASPT2) method is presented, which utilizes domains of pair natural orbitals and projected atomic orbitals for the virtual space to achieve linear scaling of the computational effort with the number of inactive orbitals. The method is applied to compute excitation energies of medium size aromatic molecules, and it is shown that the impact of the local approximations on the computed excitation energies is negligible. The applicability and efficiency of the method are demonstrated for two large molecular systems with up to 400 correlated electrons, nearly 3000 basis functions, and 45 electronic states. Furthermore, some approximations in the CASPT2 zeroth-order Hamiltonian, which decouple different configuration spaces, are proposed and tested. These approximations allow us to reuse many integrals and amplitudes from the ground state in the excited states, thereby significantly reducing the computational effort for calculations with many states. Using appropriate correction terms, the impact of these approximations is shown to be small.
Microfluidic analog of an opposed-jets device
Authors: Haward S. J. , Hopkins C. C. , Toda-Peters K. , Shen A. Q.
Published: June 2019

A fully three-dimensional (3D) stagnation point microfluidic device is fabricated that, similar to the classical opposed-jet apparatus, can be operated in either a uniaxial or a biaxial extensional flow mode with an easily controllable strain rate. The microchannel is etched inside fused silica and has optical access through all three planes. A detailed characterization of the Newtonian flow field by microparticle image velocimetry confirms the expected nature of the flow and compares well with the prediction of 3D numerical simulations. Flow-induced birefringence of a model polymer solution demonstrates the extension of macromolecules in both modes of operation and the potential use of the device for quantitative rheo-optical studies. This microfluidic opposed jet device could also be used for examining the deformation and dynamics of drops, cells, fibers, and single molecules in well-defined and relevant flow fields.
Large superelastic recovery and elastocaloric effect in as-deposited additive manufactured Ni50.8Ti49.2 alloy
Authors: Wan Xueman , Feng Yan , Lin Xin , Tan Hua
Published: June 2019

A Ni50.8Ti49.2 alloy is fabricated by the Laser Solid Forming (LSF) technique by using prealloyed powder in this work. Characterization of the microstructure, phase transformation, and shape recovery of the as-deposited alloy are explored. Columnar grains with ⟨110⟩ preferred orientation are well aligned with the building direction, and the martensitic transformation (MT) behavior shows spatial distribution characteristics. With the increase in the deposited height, MT varies from the two-stage B2 →R→ B19′ transformation to the one-stage B2 → B19′ transformation. Shape recovery properties are studied by compression tests. The as-deposited material without any further heat treatment shows a remarkably large superelastic recovery strain of 9.2% at room temperature, which is the largest value in the additive manufactured NiTi alloy. A negative adiabatic temperature change of –18.6 K induced by the elastocaloric effect during the unloading process is obtained. The shape memory effect (SME) of the as-deposited LSF Ni50.8Ti49.2 alloy is not only dependent on the detwinning of martensite but also associated with the partial superelasticity of the parent phase in the present work, demonstrating a unique two-stage yielding behavior. A residual strain up to 6% is recovered while heating, indicating an excellent SME.
The MgCO3–CaCO3–Li2CO3–Na2CO3–K2CO3 melts: Thermodynamics and transport properties by atomistic simulations
Authors: Desmaele Elsa , Sator Nicolas , Vuilleumier Rodolphe , Guillot Bertrand
Published: June 2019

Atomistic simulations provide a meaningful way to determine the physicochemical properties of liquids in a consistent theoretical framework. This approach takes on a particular usefulness for the study of molten carbonates, in a context where thermodynamic and transport data are crucially needed over a large domain of temperatures and pressures (to ascertain the role of these melts in geochemical processes) but are very scarce in the literature, especially for the calcomagnesian compositions prevailing in the Earth’s mantle. Following our work on Li2CO3–Na2CO3–K2CO3 melts, we extend our force field to incorporate Ca and Mg components. The empirical interaction potentials are benchmarked on the density data available in the experimental literature [for the crystals and the K2Ca(CO3)2 melt] and on the liquid structure issued from ab initio molecular dynamics simulations. Molecular dynamics simulations are then performed to study the thermodynamics, the microscopic structure, the diffusion coefficients, the electrical conductivity, and the viscosity of molten Ca,Mg-bearing carbonates up to 2073 K and 15 GPa. Additionally, the equation of state of a Na–Ca–K mixture representative of the lavas emitted at Ol Doinyo Lengai (Tanzania) is evaluated. The overall agreement between the MD results and the existing experimental data is very satisfactory and provides evidence for the ability of the force field to accurately model any MgCO3–CaCO3–Li2CO3–Na2CO3–K2CO3 melt over a large T–P range. Moreover, it is the first report of a force field allowing us to study the transport properties of molten magnesite (MgCO3) and molten dolomite [CaMg(CO3)2].
Unidirectional distributed acoustic reflection transducers for quantum applications
Authors: Dumur É. , Satzinger K. J. , Peairs G. A. , Chou Ming-Han , Bienfait A. , Chang H.-S. , Conner C. R. , Grebel J. , Povey R. G. , Zhong Y. P. , Cleland A. N.
Published: June 2019

Recent significant advances in coupling superconducting qubits to acoustic wave resonators have led to demonstrations of quantum control of surface and bulk acoustic resonant modes as well as Wigner tomography of quantum states in these modes. These advances were achieved through the efficient coupling afforded by piezoelectric materials combined with GHz-frequency acoustic Fabry-Perot cavities. Quantum control of “itinerant” surface acoustic waves appears in reach but is challenging due to the limitations of conventional transducers in the appropriate gigahertz-frequency band. In particular, gigahertz-frequency unidirectional transducers would provide an important addition to the desired quantum toolbox, promising unit efficiency with directional control over the surface acoustic wave emission pattern. Here, we report the design, fabrication, and experimental characterization of unidirectional distributed acoustic reflection transducers demonstrating a high transduction frequency of 4.8 GHz with a peak directivity larger than 25 dB and a directivity greater than 15 dB over a bandwidth of 17 MHz. A numerical model reproduces the main features of the transducer response quite well, with ten adjustable parameters (most of which are constrained by geometric and physical considerations). This represents a significant step toward quantum control of itinerant quantum acoustic waves.