bluuebunny/crossref_metadata_2025 huggingface dataset:
Inducible Nitric Oxide Expression Correlates with the Level of Inflammation in Periapical Cysts
Authors: Matsumoto Mariza Akemi , Ribeirob Daniel Araki
Published: October 2019

Objectives: In an attempt to elucidate if inducible nitric oxide expression (iNOS) is correlated with the level of inflammation in periapical cysts with accuracy, the goal of this study was to evaluate the expression of iNOS in these ones.

Methods: 30 cases were included in this study being iNOS evaluated by means of immunohistochemistry. Statistical analysis was performed by Kruskal-Wallis non-parametric test followed by the post-hoc Dunn’s test.

Results: iNOS stain was detected throughout the epithelium, subepithelial fibroblasts and macrophages in all cases, indistinctly. Nevertheless, iNOS immunostaining in periapical cysts was different according to the levels of inflammation, being the strongest effect associated with intense inflammatory infiltrate.

Conclusions: Taken together, our results indicate that immunoreactivity of iNOS was expressed in several cellular types present in periapical cyst, being positively correlated with the level of inflammation. Therefore, iNOS expression plays an important role in the pathogenesis of periapical cysts. (Eur J Dent 2007;1:212-215)
Bond strength of one-step self-etch adhesives and their predecessors to ground versus unground enamel
Authors: Yazici A. Ruya , Yildirim Zeren , Ertan Atila , Ozgunaltay Gül , Dayangac Berrin , Antonson Sibel A , Antonson Donald E
Published: October 2019

Objectives: The aim of this study was to compare the shear bond strength of several self-etch adhesives to their two-step predecessors to ground and unground enamel.

Methods: Seventy-five extracted, non-carious human third molar teeth were selected for this study. The buccal surfaces of each tooth were mechanically ground to obtain flat enamel surfaces (ground enamel), while the lingual surfaces were left intact (unground enamel). The teeth were randomly divided into five groups according to the adhesive systems (n=15): one-step self-etch adhesive - Clearfil S3 Bond, its two-step predecessor - Clearfil SE Bond, one-step self-etch adhesive - AdheSE One, and its two-step predecessor - AdheSE, and a two-step etch-and-rinse adhesive - Adper Single Bond 2(control). After application of the adhesives to the buccal and lingual enamel surfaces of each tooth, a cylindrical capsule filled with a hybrid composite resin (TPH) was seated against the surfaces. The specimens were stored in distilled water at 37°C for 24 hours, followed by thermocycling (5°C-55°C/500 cycles). They were subjected to shear bond strength test in a universal testing machine at a crosshead speed of 1.0 mm/minute. The data were compared using a two-way ANOVA, followed by Bonferroni test at P<.05

Results: All adhesives exhibited statistically similar bond strengths to ground and unground enamel except for the etch-and-rinse adhesive that showed significantly higher bond strengths than the self-etch adhesives (P<.05). No significant differences in bond strength values were observed between ground and unground enamel for any of the adhesives tested (P=.17).

Conclusions:Similar bond strengths to ground and unground enamel were achieved with one-step self-etch adhesives and their predecessors. Enamel preparation did not influence the bonding performance of the adhesives tested. (Eur J Dent 2012;6:280-286)
Cone-beam computed tomography analysis of the vestibular surgical pathway to the palatine root of the maxillary first molar
Authors: Kalender Atakan , Aksoy Umut , Basmaci Fatma , Orhan Kaan , Isil Orhan Ayse
Published: October 2019

Objective: The aim of this study was to evaluate the anatomical distance between apices of the palatine root of the maxillary first molars to the buccal bone plate to identify the vestibular surgical pathway in a Turkish adult population using cone-beam computed tomography (CBCT) images.

Methods: CBCT scans of 107 (48 male and 59 female) patients were retrospectively analyzed. The overall mean age was 38.6 years. The distance between the vestibular cortex and vestibular side of the palatine root was measured for 192 maxillary first molars both on axial images parallel to the palatal plane and on reformatted cross-sectional images. A Pearson’s chi square test and Mann- Whitney U-test were performed to evaluate differences among age, localization, and measurements. Differences were considered statistically significant at P<.05.

Results: The mean distance between the buccal cortex and the buccal side of the palatine root of the superior first molar in both male and female patients was 10.13 and 9.70 mm, respectively. The incidence of interposition of the lateral recess of the maxillary sinus between the roots was 42.2% and 49% in men and women, respectively. Statistically significant sex-related differences were found in the vestibular surgical pathway (P<.05).

Conclusions: For precise planning of endodontic surgery, it is crucial to determine the exact dimensions and location of the periapical lesion, as well as its relationship with the roots and other neighboring anatomical structures. CBCT can be a powerful tool for the evaluation of surgical cases in three dimensions with less ionizing radiation and better avoidance of complications during surgery. (Eur J Dent 2013;7:35-40)
Treponema diversity in root canals with endodontic failure
Authors: Nóbrega Leticia M. M. , Delboni Maraisa G. , Martinho Frederico C. , Zaia Alexandre A , Ferraz Caio C. R. , Gomes Brenda P. F. A.
Published: October 2019

Objective: This study sought to investigate the prevalence of eight oral Treponemas (Treponema denticola, T. amylovorum, T. maltophilum, T. medium, T. pectinovorum, T. socranskii, T. vicentii and T. lecithinolyticum) in teeth with endodontic treatment failure and periapical lesion.

Methods: Samples were taken from 40 root canals presenting endodontic failure and periapical lesion. DNA extraction was performed and Nested-PCR technique was used for the detection of Treponema species using specific primers.

Results: Treponemas was detected in 56.5% of the samples analyzed (22/39). Individual root canals yielded a maximum of 6 target Treponema species. T. denticola (30.8%) and T. maltophilum (30.8%) were the most frequently detected species followed by T. medium (20.5%), T. socranskii (20.5%), T. pectinovorum (17.9%) and T. vicentii (17.9%). Positive association was verified between T. denticola and T. maltophilum such as T. medium (P<.05). T. lecithinolyticum was positively associated with intraradicular post (P<.05).

Conclusion: The present study revealed that a wide variety of Treponema species plays a role in persistent/secondary infection turning the root canal microbiota even more complex than previously described by endodontic literature. (Eur J Dent 2013;7:61-68)
Distinction between super-cooled water and ice with high duty cycle time-of-flight neutron imaging
Authors: Siegwart M. , Woracek R. , Márquez Damián J. I. , Tremsin A. S. , Manzi-Orezzoli V. , Strobl M. , Schmidt T. J. , Boillat P.
Published: October 2019

We report on measured neutron cross section data for super-cooled water and ice by time-of-flight (TOF) neutron transmission imaging. In particular, we demonstrate the use of high duty cycle (HDC)-TOF measurements to determine the local aggregate state of water with spatial resolution, by exploiting the neutron cross section dependence on the mobility of hydrogen atoms for long neutron wavelengths (>4 Å). While one can envision many different applications for this method, one example is to provide insights into the freezing mechanism during the start-up of polymer electrolyte fuel cells from below zero degrees. Unlike for other wavelength selective measurements (e.g., Bragg edge imaging), only a limited wavelength resolution is required for this method. With a chopper setup with HDC (30%), we reached a high contrast-to-noise ratio (CNR) with a contrast between ice and super-cooled water of 8%. To maximize the CNR, we optimized the duty cycle, pulse period, and image processing parameters. Moreover, we present a theoretical framework for performing such optimization calculations, which can be used to maximize CNR for any beam line and any substances. For the optimization procedure presented in this publication, we used cross section values for ice and super-cooled water measured with high wavelength resolution using wavelength frame multiplication choppers. Our results show that the aggregate state of water of a sufficiently thick layer of water (>0.5 mm) can be reliably determined for a small area (1 mm2) and with a reasonable short acquisition time of 5 min.
Experimental study of forward-facing cavity with energy deposition in hypersonic flow conditions
Authors: Sudarshan B. , Deep Sneh , Jayaram V. , Jagadeesh G. , Saravanan S.
Published: October 2019

Controlling nose surface peak heat fluxes is crucial to the design of hypersonic vehicles. In this study, we report a novel technique of convective heat flux reduction on the nose surface of a spherically blunted cone by employing a forward-facing cavity combined with heat energy deposition inside the cavity. The heat deposition is achieved by the exothermic reaction of a chromium film coated on the cavity surface. The experiments are performed in hypersonic shock tunnels using air as the test gas at free stream stagnation enthalpy conditions of 2.2 ± 0.08 MJ/kg (H1), 3.2 ± 0.018 MJ/kg (H2), and 5.4 ± 0.02 MJ/kg (H3), for a geometry of cavity length to diameter ratio of 1. Schlieren images of the flow are captured using a high-speed camera and a high-power pulsed diode laser light source. The surface heat flux measurements were performed using calibrated platinum thin film sensors. We observed that the heat deposition altered the cavity flow field significantly by lowering the flow oscillation frequency and increasing the shock standoff distances with higher oscillation amplitudes. The overall surface mean heat flux reduction is increased from ≈13% to ≈49% compared to the blunt body geometry, whose nose radius is 30 mm and enhanced with reference to the cavity without heat deposition from ≈15% to ≈35%. Chromium film surface reactions are studied using X-ray Photoelectron spectroscopy, and the results confirm that the exothermic surface reactions of the Cr thin film are attributed to the formation of oxides and nitrides of Cr.
Unsupervised learning for local structure detection in colloidal systems
Authors: Boattini Emanuele , Dijkstra Marjolein , Filion Laura
Published: October 2019

We introduce a simple, fast, and easy to implement unsupervised learning algorithm for detecting different local environments on a single-particle level in colloidal systems. In this algorithm, we use a vector of standard bond-orientational order parameters to describe the local environment of each particle. We then use a neural-network-based autoencoder combined with Gaussian mixture models in order to autonomously group together similar environments. We test the performance of the method on snapshots of a wide variety of colloidal systems obtained via computer simulations, ranging from simple isotropically interacting systems to binary mixtures, and even anisotropic hard cubes. Additionally, we look at a variety of common self-assembled situations such as fluid-crystal and crystal-crystal coexistences, grain boundaries, and nucleation. In all cases, we are able to identify the relevant local environments to a similar precision as “standard,” manually tuned, and system-specific, order parameters. In addition to classifying such environments, we also use the trained autoencoder in order to determine the most relevant bond orientational order parameters in the systems analyzed.
One-step growth of wafer-scale monolayer tungsten disulfide via hydrogen sulfide assisted chemical vapor deposition
Authors: Jia Zhiyan , Dong Jiyu , Liu Lixuan , Xiang Jianyong , Nie Anmin , Wen Fusheng , Mu Congpu , Wang Bochong , Zhai Kun , Yu Zhipeng , Kang Mengke , Liu Zhongyuan
Published: October 2019

Wafer-scale monolayer WS2 has been widely investigated. Here, we report a repeatable and low-cost one-step chemical vapor deposition method for the direct growth of a 4-in. monolayer WS2 film on a thermal oxide silicon wafer by using WO3 and H2S gas as precursors. H2S gas exhibits a high vulcanization ability and can effectively reduce the growth temperature of WS2 to 825 °C. The growth process follows a self-limiting growth to form a monolayer polycrystalline film, which is merged via many stable small-angle grain boundaries. The wafer-scale monolayer WS2 film shows uniform and high-quality electrical properties. This method helps promote the future production and application of wafer-scale monolayer sulfide.
Eighth-order virial equation of state and speed-of-sound measurements for krypton
Authors: El Hawary Ahmed , Hellmann Robert , Meier Karsten , Busemann Henner
Published: October 2019

An eighth-order virial equation of state (VEOS) for krypton, valid for temperatures up to 5000 K, was developed using the accurate potential functions proposed by Jäger et al. [J. Chem. Phys. 144, 114304 (2016)] for the pair interactions and nonadditive three-body interactions between krypton atoms. While the second and third virial coefficients were already calculated by Jäger et al., the fourth- to eighth-order coefficients were determined in the present work. A simple analytical function was fitted individually to the calculated values of each virial coefficient to obtain the VEOS in an easy-to-use analytical form. To enable a stringent test of the quality of the new VEOS, we measured the speed of sound in krypton in the temperature range from 200 K to 420 K and at pressures up to 100 MPa with a very low uncertainty (at the 0.95 confidence level) of 0.005%–0.018% employing the pulse-echo technique. In order to verify that the isotopic composition of the krypton sample conforms to that of natural krypton in air, high-precision measurements of krypton isotope ratios using a high-sensitivity noble gas mass spectrometer were performed. The extensive comparison with the new speed-of-sound data as well as with experimental p-ρ-T and speed-of-sound data from the literature indicates that pressures and speeds of sound calculated using our new VEOS have uncertainties (at the 0.95 confidence level) of less than 0.1% at state points at which the VEOS is sufficiently converged.
New approach probes vibrational modes of solutions that cause singlet fission
Authors: Liebendorfer Adam
Published: October 2019

Examing carbon-hydrogen stretch of side groups of TIPS-pentacene provides signatures for the formation of triplet excited states.
Photo-Nernst effect used to detect cyclotron resonance in graphene
Authors: Frank Jodi Ackerman
Published: October 2019

The photo-thermoelectric approach could facilitate the development of far-infrared and other types of light detectors.
Harmonic analysis on the rank-

value group of a two-dimensional local field
Authors: Osipov D. V. , Parshin A. N.
Published: October 2019

In this work we construct a harmonic analysis on free Abelian groups of rank

, namely: we construct and investigate spaces of functions and distributions, Fourier transforms and actions of discrete and extended discrete Heisenberg groups. In the case of the rank-

value group of a two-dimensional local field with finite last residue field we connect this harmonic analysis with harmonic analysis on the two-dimensional local field, where the latter harmonic analysis was constructed in earlier works by the authors.

Bibliography: 15 titles.
Aggregatibacter actinomycetemcomitans
colonization and persistence in a primate model
Authors: Velusamy Senthil Kumar , Sampathkumar Vandana , Ramasubbu Narayanan , Paster Bruce J. , Fine Daniel H.
Published: October 2019

Significance

Aggregatibacter actinomycetemcomitans
, a microorganism associated with aggressive periodontitis, can result in tooth loss and systemic complications. The hyperleukotoxin-producing
A. actinomycetemcomitans
strain demonstrates up-regulation of attachment genes, permitting it to attach better than the wild-type strain in competition with commensal bacteria for space on tooth surfaces. Further, the availability of lactate provided by streptococci and other members of the indigenous plaque microbiota consorting with
A. actinomycetemcomitans
reduces its competition for glucose as a main carbon source and assists already-attached strains in growth and persistence in the developing plaque biofilm. Data derived from in vivo and in vitro studies illustrate functional strategies that allow
A. actinomycetemcomitans
to colonize and survive in the competitive and stressful environment of the oral cavity.
Wnt activator FOXB2 drives the neuroendocrine differentiation of prostate cancer
Authors: Moparthi Lavanya , Pizzolato Giulia , Koch Stefan
Published: October 2019

Significance

Aberrant activation of the homeostatic Wnt signaling pathway is a hallmark of various types of cancer. In many cases, it is unclear how elevated Wnt levels are maintained in the absence of activating pathway mutations. Here we find that the uncharacterized transcription factor FOXB2, whose expression is usually restricted to the developing brain, is induced in aggressive prostate cancer. FOXB2 strongly activates Wnt signaling via the induction of multiple pathway agonists, particularly the neurogenic ligand WNT7B. Accordingly, our analyses suggest that FOXB2 imposes a neuronal differentiation program on prostate cancer cells, which is associated with treatment failure and poor prognosis. Thus, our work identifies FOXB2 as a tissue-specific Wnt activator that may play a role in prostate cancer progression.
A tetrapeptide class of biased analgesics from an Australian fungus targets the µ-opioid receptor
Authors: Dekan Zoltan , Sianati Setareh , Yousuf Arsalan , Sutcliffe Katy J. , Gillis Alexander , Mallet Christophe , Singh Paramjit , Jin Aihua H. , Wang Anna M. , Mohammadi Sarasa A. , Stewart Michael , Ratnayake Ranjala , Fontaine Frank , Lacey Ernest , Piggott Andrew M. , Du Yan P. , Canals Meritxell , Sessions Richard B. , Kelly Eamonn , Capon Robert J. , Alewood Paul F. , Christie MacDonald J.
Published: October 2019

Significance

Agonists of the μ-opioid receptor (MOPr) are currently the gold standard for pain treatment. However, their therapeutic usage is greatly limited by side effects including respiratory depression, constipation, tolerance, and dependence. Functionally selective MOPr agonists that mediate their effects preferentially through G proteins rather than β-arrestin signaling are believed to produce fewer side effects. Here, we present the discovery of 3 unusual tetrapeptides with a unique stereochemical arrangement of hydrophobic amino acids from an Australian estuarine isolate of
Penicillium
species. Building on these natural templates we developed bilorphin, a potent and selective highly G protein-biased agonist of the MOPr. Further, through the addition of a simple sugar moiety, we generated bilactorphin that is an effective analgesic in vivo.
A mesophilic cysteine-less split intein for protein
trans
-splicing applications under oxidizing conditions
Authors: Bhagawati Maniraj , Terhorst Tobias M. E. , Füsser Friederike , Hoffmann Simon , Pasch Tim , Pietrokovski Shmuel , Mootz Henning D.
Published: October 2019

Significance

Protein
trans
-splicing catalyzed by split inteins is a powerful tool for traceless posttranslational protein modification. For example, it can be used to reconstitute a protein from 2 fragments, append a peptide tag to a protein, or cyclize a polypeptide. We report the first cysteine-less (CL) split intein that is high yielding under native and physiological conditions. In contrast to cysteine-containing inteins, the split CL intein is fully operational under oxidizing conditions, i.e., in the absence of reducing agents. Leveraging this property, we utilize the CL intein to selectively conjugate fluorophores to disulfide-containing antibody fragments, and to target membrane receptors on living cells. Carrying out the experimental protocol under oxidizing conditions avoids protein damage due to reduction of disulfide bonds.
Structure of
Pseudomonas aeruginosa
ribosomes from an aminoglycoside-resistant clinical isolate
Authors: Halfon Yehuda , Jimenez-Fernandez Alicia , La Rosa Ruggero , Espinosa Portero Rocio , Krogh Johansen Helle , Matzov Donna , Eyal Zohar , Bashan Anat , Zimmerman Ella , Belousoff Matthew , Molin Søren , Yonath Ada
Published: October 2019

Resistance to antibiotics has become a major threat to modern medicine. The ribosome plays a fundamental role in cell vitality by the translation of the genetic code into proteins; hence, it is a major target for clinically useful antibiotics. We report here the cryo-electron microscopy structures of the ribosome of a pathogenic aminoglycoside (AG)-resistant
Pseudomonas aeruginosa
strain, as well as of a nonresistance strain isolated from a cystic fibrosis patient. The structural studies disclosed defective ribosome complex formation due to a conformational change of rRNA helix H69, an essential intersubunit bridge, and a secondary binding site of the AGs. In addition, a stable conformation of nucleotides A1486 and A1487, pointing into helix h44, is created compared to a non-AG-bound ribosome. We suggest that altering the conformations of ribosomal protein uL6 and rRNA helix H69, which interact with initiation-factor IF2, interferes with proper protein synthesis initiation.
Myelin sheath structure and regeneration in peripheral nerve injury repair
Authors: Liu Bin , Xin Wang , Tan Jian-Rong , Zhu Rui-Ping , Li Ting , Wang Dan , Kan Sha-Sha , Xiong Ding-Kui , Li Huan-Huan , Zhang Meng-Meng , Sun Huan-Huan , Wagstaff William , Zhou Chan , Wang Zhi-Jian , Zhang Yao-Guang , He Tong-Chuan
Published: October 2019

Significance

Afferent and efferent nerve fibers cannot be distinguished based on the axonal diameter or the presence of the Remark bundle. The compaction of the myelin sheath involves 2 steps: 1) The distance between the 2 layers of cell membranes in the double-bilayer decreases; 2) the adjacent double-bilayers close to form MDL. The expression of MBP is positively correlated with the formation of the MDL. Anchoring of the myelin sheath by lipophilin particles might be required for the formation of a compacted myelin sheath. The abnormalities in nerve fiber structure observed in autologous nerve grafts do not appear to be related to either MBP or lipophilin, so further research is needed to determine their causes.
Population-based neuroimaging reveals traces of childbirth in the maternal brain
Authors: de Lange Ann-Marie G. , Kaufmann Tobias , van der Meer Dennis , Maglanoc Luigi A. , Alnæs Dag , Moberget Torgeir , Douaud Gwenaëlle , Andreassen Ole A. , Westlye Lars T.
Published: October 2019

Significance

Pregnancy is one of the most dynamic periods in a woman’s life, involving a remarkable potential for brain plasticity that promotes cognitive and emotional adjustments to the newborn. We provide evidence for a relationship between number of childbirths and brain aging in 12,021 middle-aged women, suggesting that potential parity-related brain changes may endure beyond the postpartum period and influence the course of neurobiological aging.
Synergistic boost of output power density and efficiency in In-Li–codoped SnTe
Authors: Guo Fengkai , Wu Haijun , Zhu Jianbo , Yao Honghao , Zhang Yang , Cui Bo , Zhang Qian , Yu Bo , Pennycook Stephen J. , Cai Wei , Chu Ching-Wu , Sui Jiehe
Published: October 2019

Significance

In the search for high-performance thermoelectric materials, in addition to conversion efficiency, output power density is also an important consideration for practical applications in generating electrical energy from solar or waste heat. We designed and fabricated an SnTe-based material that exhibits both high conversion efficiency and high output power density by indium and lithium codoping. Indium doping realizes the resonant state in the compound, while lithium doping further increases its carrier concentration by acting as an acceptor as well as dramatically reducing its lattice thermal conductivity by forming disperse precipitates. This work provides an example for finding high-performance thermoelectric materials that are suitable for practical application and provides guidance for future research.
PRC2 engages a bivalent H3K27M-H3K27me3 dinucleosome inhibitor
Authors: Diehl Katharine L. , Ge Eva J. , Weinberg Daniel N. , Jani Krupa S. , Allis C. David , Muir Tom W.
Published: October 2019

Significance

A subset of deadly pediatric brain tumors called diffuse intrinsic pontine gliomas express a mutant histone H3 with a lysine-to-methionine substitution at position 27 (H3K27M), which has been shown to drive tumorigenesis in these cancers. While there is evidence that H3K27M inhibits the H3K27 methyltransferase known as polycomb repressive complex 2 (PRC2), the precise mechanisms by which H3K27M acts remain a matter of debate. In this work, we used biochemical and in cell assays to characterize the dependence of PRC2 binding to H3K27M on other PRC2 ligands, including H3K27me3. We synthesized designer chromatin inhibitors containing H3K27M and H3K27me3 nucleosomes and found that PRC2 is inhibited by a dinucleosome, suggesting that PRC2 is sequestered on chromatin by these bivalent inhibitors.
Tunable corrugated patterns in an active nematic sheet
Authors: Senoussi Anis , Kashida Shunnichi , Voituriez Raphael , Galas Jean-Christophe , Maitra Ananyo , Estevez-Torres André
Published: October 2019

Significance

To what extent can we engineer matter that shapes itself? To investigate this question we study an aqueous solution containing molecular motors that walk on protein filaments. When the filaments are long and attract each other, bundles of filaments are parallelly oriented. We show that such a nematic solution in the presence of multimers of motors has an unexpected behavior: It forms a fluid film that autonomously wrinkles. The observed wrinkles have a well-defined wavelength that decreases with increasing motor concentration. The wrinkles either are stable or break into a chaotic flowing state at high motor concentration, providing insights into how to engineer static or dynamic materials with this class of active matter.
Electrostatic shape control of a charged molecular membrane from ribbon to scroll
Authors: Gao Changrui , Kewalramani Sumit , Valencia Dulce Maria , Li Honghao , McCourt Joseph M. , Olvera de la Cruz Monica , Bedzyk Michael J.
Published: October 2019

Bilayers of amphiphiles can organize into spherical vesicles, nanotubes, planar, undulating, and helical nanoribbons, and scroll-like cochleates. These bilayer-related architectures interconvert under suitable conditions. Here, a charged, chiral amphiphile (palmitoyl-lysine, C
16
-K
1
) is used to elucidate the pathway for planar nanoribbon to cochleate transition induced by salt (NaCl) concentration. In situ small- and wide-angle X-ray scattering (SAXS/WAXS), atomic force and cryogenic transmission electron microscopies (AFM and cryo-TEM) tracked these transformations over angstrom to micrometer length scales. AFM reveals that the large length (L) to width (W) ratio nanoribbons (L/W > 10) convert to sheets (L/W → 1) before rolling into cochleates. A theoretical model based on electrostatic and surface energies shows that the nanoribbons convert to sheets via a first-order transition, at a critical Debye length, with 2 shallow minima of the order of thermal energy at L/W >> 1 and at L/W = 1. SAXS shows that interbilayer spacing (
D
) in the cochleates scales linearly with the Debye length, and ranges from 13 to 35 nm for NaCl concentrations from 100 to 5 mM. Theoretical arguments that include electrostatic and elastic energies explain the membrane rolling and the bilayer separation–Debye length relationship. These models suggest that the salt-induced ribbon to cochleate transition should be common to all charged bilayers possessing an intrinsic curvature, which in the present case originates from molecular chirality. Our studies show how electrostatic interactions can be tuned to attain and control cochleate structures, which have potential for encapsulating, and releasing macromolecules in a size-selective manner.
III–V/Si Hybrid Laser Array with DBR on Si Waveguide*
Authors: Li Yan-Ping , Yuan Li-Jun , Tao Li , Chen Wei-Xi , Wang Bao-Jun , Pan Jiao-Qing
Published: October 2019

We report an eight-channel silicon evanescent laser array operating at continuous wave under room temperature conditions using the selective-area metal bonding technique. The laser array is realized by evanescently coupling the optical gain of InGaAsP multi-quantum wells to the silicon waveguides of varying widths and patterned with distributed Bragg reflector gratings. The lasers have emission peak wavelengths in a range of 1537–1543 nm with a wavelength spacing of about 1.0 nm. The thermal impedances Z
T
of these hybrid lasers are evidently lower than those DFB counterparts
Dramatic Spectral Broadening of Ultrafast Laser Pulses in Molecular Nitrogen Ions*
Authors: Chen Jin-Ming , Yao Jin-Ping , Liu Zhao-Xiang , Xu Bo , Zhang Fang-Bo , Wan Yue-Xin , Chu Wei , Wang Zhen-Hua , Qiao Ling-Ling , Cheng Ya
Published: October 2019

We investigate nonlinear interaction of nitrogen molecules with a two-color laser field composed by an intense 800 nm laser pulse and a weak 400 nm laser pulse. It is demonstrated that the spectrum of 400 nm pulses is dramatically broadened when the two beams temporally overlap. In comparison, the spectral broadening in argon is less pronounced, although argon atoms and nitrogen molecules have comparable ionization potentials. We reveal that the dramatic spectral broadening originates from the greatly enhanced nonlinear optical effects in the near-resonant condition of interaction between the 400 nm pulses and the nitrogen molecular ions.
Charge Transport Properties of the Majorana Zero Mode Induced Noncollinear Spin Selective Andreev Reflection*
Authors: Shang Xin , Liu Hai-Wen , Xia Ke
Published: October 2019

We study the charge transport properties of the spin-selective Andreev reflection (SSAR) effect between a spin polarized scanning tunneling microscope (STM) tip and a Majorana zero mode (MZM). Considering both the MZM and the excited states, we calculate the conductance and the shot noise power of the noncollinear SSAR using scattering theory. We find that the excited states give rise to inside peaks. Moreover, we numerically calculate the shot noise power and the Fano factor of the SSAR effect. Our calculation shows that the shot noise power and the Fano factor are related to the angle between the spin polarization direction of the STM tip and that of the MZM, which provide additional characteristics to detect the MZM via SSAR.
Roles of Nano-Domain Switching and Non-180° Domains in Enhancing Local Piezoelectric Responses of Highly (100)-Oriented Pb(Zr0.60Ti0.40)O3 Thin Films*
Authors: Jin Chen-Fei , Zhang Si-Qi , Shen Zhi-Qiang , Li Wei-Li
Published: October 2019

Ferroelectric Pb(Zr
0.60
Ti
0.40
)O
3
thin films deposited on the niobium-doped SrTiO
3
and Pt (111)/Ti/SiO
2
/Si substrates are fabricated by a sol-gel method. X-ray diffraction indicates that the films have a ‘cube-on-cube’ growth with highly (100) preferred orientation and good surface qualities. Using piezoelectric force microscopy, we investigate domain structures and butterfly amplitude loops of ferroelectric thin films. The results indicate that the film deposited on Nb:SrTiO
3
has both kinds of 180° polarizations perpendicular or parallel to the surface while the film deposited on Pt/Ti/SiO
2
/Si has irregular phase differences. Excellent piezoelectric polarization are observed in the films on niobium-doped SrTiO
3
with local

d

33

∗

values around 45 pm/V three times more than that of the films around 13 pm/V deposited on Pt (111)/Ti/SiO
2
/Si. Our findings emphasize that nano-domain switching ability and non-180° domains will contribute significantly to enhance piezoelectric responses of ferroelectric thin films.
Superconductivity in Weyl Semimetal NbP: Bulk vs. Surface
Authors: Baenitz M , Schmidt M , Suess V , Felser C , Lüders K
Published: October 2019

Transition metal monopnictides belong to the new class of semimetals where the bulk properties are determined by the presence of pairs of nodes with different chirality formed by linear dispersive states in the k-space. Beside the anomaly in the bulk magnetotransport superconductivity is frequently found in some Weyl semimetals. We found signatures of superconductivity in ac and dc magnetization measurements of highly pure and stoichiometric NbP powder. We determined the lower and upper critical field and the Ginzburg-Landau parameter. The relative small superconducting volume fraction is related to either effect of finite grain size and/or surface superconductivity. The last mentioned may originate from either off stoichiometric (Nb-rich) surface layers or a strained surface with different electronic properties. Furthermore the intrinsic normal state susceptibility is determined taking into account a paramagnetic contribution of a few ppm of magnetic impurities.
Effect of non-magnetic rare earth substitution for Zr on mixed anion Zr(P, Se)2 superconductors II
Authors: Iwakiri K , Nishio T , Kawashima K , Ishida S , Oka K , Fujihisa H , Gotoh Y , Hase I , Iyo A , Ogino H , Eisaki H , Yoshida Y , Kitô H
Published: October 2019

In ZrP1.25Se0.75, the superconducting transition temperature T
c is increased from 5.8 K to 7.6 K when Sc atoms are partially substituted for Zr atoms having almost the same atomic radius as Sc atoms. Transport measurements show that holes are doped with substituting Sc atoms. The density of states in (Zr, Sc)P1.25Se0.75 is derived from band structure calculations and its implication in the doping behaviour and the increase of T
c is discussed.
Transmission EBSD (t-EBSD) to determine grain and grain boundary properties on nanostructured superconductor samples
Authors: Koblischka-Veneva A. , Koblischka M. R. , Schmauch J. , Murakami M.
Published: October 2019

The knowledge of the properties of the grains and their grain boundaries is essential for the further optimization of sample performance of various high-T
c samples (YBa2Cu3O
y
(YBCO), Bi-based cuprates, MgB2, iron-based materials). In these materials either the grains are of nanometer dimensions or the various additions of secondary phase(s) to improve the flux pinning are required to be of nanometer dimensions, so a high achievable resolution and better imaging properties are important to obtain reasonably high image quality of the recorded Kikuchi patterns to enable automated orientation mapping using the EBSD technique. Therefore, the newly developed transmission-EBSD (t-EBSD) technique is the method of choice to analyze the grain and the grain boundary properties in such nanostructured superconducting materials. Several results obtained on MgB2, melt-textured, infiltration-growth processed YBCO and electrospun Bi2Sr2CaCu2O8 nanowires are presented.
Optimization of YbBa2Cu3Oy Thick Film Formation on MgO Substrates using Yb2BaO5 and liquid phase
Authors: Hattori A. , Muralidhar M. , Sai Srikanth A. , Murakami M.
Published: October 2019

The production of best thick YbBa2Cu3Oy (Yb123) films on MgO substrates are crucial for the utilization of this technology in silver sheeted wire as similar to Bi-2223. In this work, in order to optimize YbBa2Cu3Oy films on MgO substrates, a mixture of alpha-terpineol and 2-ethyl acetate was utilized as a solvent to which 100 nm sized stoichiometric powder mixture of Yb2BaO5, BaCuO2 and CuO was added and grinded for several hours to form a highly dense paste. Thick film precursors were prepared by spreading the paste over MgO substrates with a screen printing technique and various sintered and quench studies are done. Growth temperature is systematically varied between 800 and 950 °C for 30 minutes in air and quenched in liquid nitrogen. Similarly, sintering durations are varied systematically from 15 minutes to 8 hours. XRD reveals conformed that large Yb123 grains are formed when the thick films are sintered at 825 °C for 1 hour on MgO substrate. SEM micrographs are also in congruence with the XRD results depicting the giant Yb123 crystals. The present results clearly demonstrate that optimization of the growth temperature and time is crucial to obtain the large thick YbBa2Cu3Oy films on MgO substrates.
Effects of vicinal substrates on the orientation of Bi2Sr2CaCu2O8+x thin films when the metal-organic decomposition method is used
Authors: Yamada Y , Okamoto T
Published: October 2019

We have prepared (010) (or (100)) oriented Bi2Sr2CaCu2O8+x
(Bi2212) thin films by metal-organic decomposition (MOD) method which is one kind of solution method. The flat and vicinal (100) substrate (the miscut angle φ = 5° toward the direction [001]) of NdGaO3 (NGO) was used. When using vicinal substrates, the Bi2212 (020) (or (200)) peak appeared clearly in the XRD patterns. From the SEM image, it was found that elongated plate-like crystal grains of Bi2212 were grown. From the viewpoint of lattice matching, this elongated crystal grain is considered to be (010) (or (100)) oriented Bi2212 crystal grains.
Dynamics of a vortex system in a layered high-temperature superconductor under a pulsed current impact
Authors: Rudnev I A , Maksimova A N , Moroz A N , Kashurnikov V A
Published: October 2019

By using the Monte Carlo method, electric field relaxation has been numerically studied in a 2D layered HTS with defects. Time dependences of the electric field strength inside the sample for an instantaneous rise of electric current have been calculated for different temperatures. The influence of temperature on the shape of such dependences has been demonstrated. The impact of a rectangular current pulse on the vortex system has been studied. The value of the response field strength and its dependence on the amplitude and duration of the pulse have been calculated as well as the impact of pulse duration on the shape of the response.
Critical states in two overlapped rectangular superconducting plates
Authors: Ooi Shinsuke , Kato Masaru
Published: October 2019

We study vortex penetration into two-layer structures of superconducting plates under a perpendicular magnetic field. We solve the heat transport equation and the Maxwell equations with the current-voltage relation for superconductor, simultaneously, and obtain magnetic flux and current densities. We show how magnetic flux structure depends on the structure, especially distance of two-layer of superconductors.
Impurity induced insulator-to-metal transitions in half-filled Mott insulators
Authors: Yokoyama Hisatoshi , Sato Ryo , Kobayashi Kenji
Published: October 2019

In view of cuprate superconductors, effects of point-type impurity potential (V) on half-filled antiferromagnetic and paramagnetic states are studied for a strongly correlated square-lattice Hubbard model (U/t = 12) with a diagonal transfer (t′), using a variational Monte Carlo method. In the trial states, we introduce a Rice-Brinkman-type one-body projector for V, which enables us to treat the whole range of V (− ∞ < V/t < ∞) with small statistical errors. Filling-control-type Mott (insulator-to-metal) transitions are found to occur at

V
=

V
U

(
±
)

(∼ ±U). In the metallic states

(

|
V
|

>

|

V
U

(
±
)

|

)

, charge carriers are holes (electrons) in the case of attractive (repulsive) potential. The mechanism of the transitions is intuitively understood.
Antiferromagnetism, superconductivity and phase diagram in the three-band model of high-temperature cuprates
Authors: Yanagisawa Takashi
Published: October 2019

We investigate the ground state of the two-dimensional three-band d-p model for for high-temperature superconductors on the basis of a variational Monte Carlo method. We employ an optimization variational Monte Carlo method that we have developed recently. The many-body wave function is improved beyond the Gutzwiller ansatz by adopting the wave function in the form ψ = exp(−S)ψG
where ψG
represents the Gutzwiller function and S is a kinetic operator. The strong magnetic correlation and also superconductivity (SC) are induced by the on-site Coulomb repulsive interaction. It is important to clarify the phase diagram that includes superconductive phase and antiferromagnetic phase. We show the phase diagram to show the antiferromagnetic region in the parameter space. High-temperature superconductivity may occur in the strongly correlated region near the antiferromagnetic boundary.
Evaluation of superconducting properties for YBa2Cu3Oy coated conductors fabricated by self-heating technique in Pulsed Laser Deposition method
Authors: Sato W. , Tsuchiya Y. , Ichino Y. , Yoshida Y.
Published: October 2019

We fabricated YBa2Cu3O
y
coated conductors with 0.4 - 4.0 μm in the thickness on IBAD-MgO template deposited on Hastelloy metal substrates which were heated by a self-heating (S-H) technique in pulsed laser deposition method. The self-heating (S-H) technique is a method to heat a metal substrate by the Joule heat. In addition, preset substrate temperature (T
s) was gradually changed during the film deposition. It is possible to suppress a-axis grains even in a thick film by the S-H technique. Critical current density (J
c) and critical current (I
c) reached 2.0 MA/cm2 and 800 A/cm-width in a film with the thickness of 4.0 μm at 77 K and self-field.
Development of multi-filamentated long EuBCO coated conductors with BHO doping by plane-plume PLD method
Authors: Ibi A , Machi T , Nakaoka K , Sato M , Izumi T , Higashikawa K , Kiss T
Published: October 2019

Long REBa2Cu3Ox (REBCO, RE: rare earth element) coated conductors with BaMO3 (BMO, M: metal) doping have been expected for the industrial and commercial applications. It is known that critical current (I
c) of REBCO coated conductors (with or without artificial pinning centers doping) in magnetic field at high temperature is superior to the other superconducting wires. Especially, we have found that EuBa2Cu3Ox (EuBCO) coated conductors with BaHfO3 (BHO) doping show higher critical current density (J
c) and I
c at high temperature in self and magnetic fields than those of YBa2Cu3Ox and GdBa2Cu3Ox coated conductors with BHO doping. However, in order to realize EuBCO coated conductors with BHO doping for various applications such as an armature coil, the much higher uniformity of not only longitudinal and but transversal I
c distributions of long REBCO coated conductors with high in-field performance for filamentary structure is required. The plane-plume PLD (pulsed laser deposition) method is performed by shortening the target-substrate distance and increasing the number of plumes with scan of X-Y axes directions to increase the deposition rate and averaging the deposition conditions which should relate to obtain the uniformity I
c distributions. We fabricated the EuBCO coated conductors with BHO doping (of 0.6 m length and 10 mm in width) by the combination of the ion-beam assisted deposition (IBAD) and the plane-plume PLD method and then we processed the multi-filamentary structure EuBCO coated conductors with BHO doping (of 8 filaments of 440 μm, 0.6 m in length and 5 mm in width) by using the excimer laser scribing to reduce the AC loss and to control the shielding current. I
c distributions in a width direction of this EuBCO coated conductor with BHO doping was improved as an uniformity of filament-I
c of 4.3 %.

Recently, we fabricated the 16 filamentary and 3 m long EuBCO coated conductor with BHO doping by IBAD / plane-plume PLD method. We confirmed that the hysteresis loss was reduce to 1/16 by a 16 filamentary EuBCO coated conductor with BHO doping comparing with EuBCO coated conductor with BHO doping without filamentation.
Dependences of AC Loss in Stacked REBa2Cu3Oy Superconducting Tapes on the Interval among Tapes under Perpendicular Magnetic Field
Authors: Sasa H , Kawasaki G , Miura S , Iwakuma I , Izumi T , Machi T , Ibi A
Published: October 2019

In this study, we focused on the dependence of the AC loss in REBa2Cu3O
y
(REBCO, RE = rare earth, Y, Eu, Gd) superconducting tapes stacked perpendicular to the tape face on the interval between the superconducting layers. The AC loss of the 2-layer stacked tapes with various interval in perpendicular field was investigated by pickup-coil method. The AC loss for external applied magnetic field, B
m, below the penetration field, B
p, increases with increasing the interval. In the case that the ratio of the distance between the neighboring superconducting layer, D, to the width of the tape, w, (D/w) is smaller than 0.1, the AC loss of 2-layer tapes decreased to 1/2 of that of 1-layer tape. On the other hand, in the case of D/w being larger than 0.1, the AC loss of 2-layer tapes was larger than 1/2 and it approached the AC loss of 1-layer tape with increasing D/w. From the result obtained in this study, it is predicted that, for B
m below B
p, the AC loss of stacked REBCO tapes with large D/w, such as multifilamentary tapes, is larger than the AC loss of stacked non-scribed REBCO tapes. However, for B
m above B
p: a large AC loss region, it is known that the AC loss of the multifilamentary tapes decreases compared with that of non-scribed tapes. Next step, AC loss of the multifilamentary tapes for B
m below B
p will be investigated experimentally and theoretically.
Fabrication of a Compact High-field Magnet by Coated Conductor Stacks
Authors: Hashimoto T , Pyon S , Iijima Y , Sugiura S , Uji S , Terashima T , Tamegai T
Published: October 2019

A bulk magnet was fabricated by stacking coated conductors with enhanced J
c by introducing nanorods. The fabricated CC stack consists of 100 pieces of CCs, and it was magnetized by field-cooling method in an applied field of 14.5 T down to 4.2 K. By reducing the magnetic field down to zero at a ramp of rate 1 T/min, we have succeeded in trapping 12.6 T at the center of the CC stack. We also confirmed that the CC stack can sustain the high trapped field for more than 20 min, which demonstrates the practical usefulness of such a staked CC magnet.
Study of the superconducting layer microstructure and (Nb,Ti,Ta)3Sn bronze strands properties
Authors: Abdyukhanov I M , Pantsyrny V I , Silaev A G , Tsapleva A S , Konovalova N V , Alekseev M V , Dergunova E A , Mareev K A , Nasibulin M N , Drobyshev V A , Kravtsova M V , Lykianov P A , Krylova M V
Published: October 2019

Superconducting materials with high current carrying capacity operating in magnetic fields up to 18 T at 4.2 K are required for promising applications in magnetic systems of high-energy physics devices, NMR-spectroscopes and others. The paper presents the study results of the Nb3Sn strands manufactured by the bronze route differed in the filament composition. The filaments were made from the alloys Nb-3.5 wt. %Ta and Nb-7.0wt.%Ta and the matrix was produced from the Cu-15.5wt.%Sn-0.25wt.%Ti alloy. To form the superconducting Nb3Sn phase a series of reaction heat treatments of conductor samples were carried out by two-stage regimes with the temperature of the second stage varying from 650 to 720 °C. The microstructure of the Nb3Sn layer was studied by scanning electron microscopy and their electro-physical characteristics were also measured. It was shown that after reaction at 575 °C, 100 h + 650 °C, 200 h samples with different Ta content had almost the same current -carrying capacity in the field range 12-18 T at 4.2 K. The critical temperature of superconductors decreased from 17.5 to 16.5 K with an increase of the second stage of reaction temperature from 650 to 720 °C.