bluuebunny/crossref_metadata_2025 huggingface dataset:
Palladium complexes of N-heterocyclic carbenes displaying an unsymmetricalN-alkylfluorenyl/N′-aryl substitution pattern and their behaviour in Suzuki–Miyaura cross coupling
Authors: Almallah Hamzé , Brenner Eric , Matt Dominique , Harrowfield Jack , Jahjah Mohamad , Hijazi Akram
Published: September 2019

Pd–PEPPSI complexes with a mixedN-alkylfluorenyl/N′-aryl substitution pattern were found to be considerably more active in Suzuki–Miyaura cross coupling than the standard complexes [PdCl2(IMes)(Py)] and [PdCl2(IPr)(Py)].
Synthesis and biological properties of tetranuclear ruthenium complexes containing the bis[4(4′-methyl-2,2′-bipyridyl)]-1,7-heptane ligand
Authors: Sun Biyun , Sundaraneedi Madhu K. , Southam Hannah M. , Poole Robert K. , Musgrave Ian F. , Keene F. Richard , Collins J. Grant
Published: September 2019

The non-linear polypyridylruthenium(ii) complex (Rubb7-TNL) exhibited good antimicrobial activity, but surprisingly was also highly active against cancer cells. The results suggestRubb7-TNLmay have potential as a new anticancer agent.
Why is NanoSIMS elemental imaging of arsenic in seaweed (Laminaria digitata) important for understanding of arsenic biochemistry in addition to speciation information?
Authors: Ender E. , Subirana M. A. , Raab A. , Krupp E. M. , Schaumlöffel D. , Feldmann J.
Published: September 2019

Brown seaweed such as Laminaria digitata is known to accumulate arsenic at a concentration of more than 100 mg kg−1.
Neutrophil trafficking on-a-chip: an in vitro, organotypic model for investigating neutrophil priming, extravasation, and migration with spatiotemporal control
Authors: McMinn Patrick H. , Hind Laurel E. , Huttenlocher Anna , Beebe David J.
Published: September 2019

Her we report a new microfluidic technology designed to facilitate the study of neutrophil trafficking and priming using primary human cells with a high degree of spatiotemporal control.
Phase change thin films for non-volatile memory applications
Authors: Lotnyk A. , Behrens M. , Rauschenbach B.
Published: September 2019

The paper reviews materials science aspects of chalcogenide-based phase change thin films relevant for non-volatile memory applications.
Azido bridged binuclear copper(ii) Schiff base compound: synthesis, structure and electrical properties
Authors: Ghosh Mrinmoy , Saha Sandip , Banerjee Abhijit , Schollmeyer Dieter , Sarkar Ananda , Banerjee Saikat
Published: September 2019

The structure, FESEM, Al/complex/ITO microstructure and the current–voltage characteristics of the copper(ii) azido bridged dimer.
Binding of ellagic acid and urolithin metabolites to the CK2 protein, based on the ONIOM method and molecular docking calculations
Authors: Shahraki Asiyeh , Ebrahimi Ali
Published: September 2019

Using three-layer ONIOM and molecular docking calculations to investigate the binding of urolithins to the active site of the CK2 protein.
Two zinc(ii)-based coordination polymers with flexible dicarboxylate and pyridine mixed ligands: effect of π⋯π interactions on electrical activity
Authors: Akhtaruzzaman Akhtaruzzaman , Das Pubali , Khan Samim , Maity Suvendu , Naaz Sanobar , Islam Sakhiul , Ghosh Prasanta , Ray Partha Pratim , Mir Mohammad Hedayetullah
Published: September 2019

We synthesized two Zn(ii)-based 1D coordination polymers with paddle-wheel units using flexible 1,4-cyclohexanedicarboxylate linkers; these compounds exhibited electrical conductivity and Schottky barrier diode behavior.
Polyelectrolyte hydrogel capsules as stabilizers for reconfigurable complex emulsions
Authors: Balaj Rebecca V. , Cho Seung Wook , Singh Prachi , Zarzar Lauren D.
Published: September 2019

Polyelectrolyte capsules stabilize biphasic oil droplets while preserving droplet reconfigurability in the presence of surfactants.
In situ growth of copper(ii) phthalocyanine-sensitized electrospun CeO2/Bi2MoO6 nanofibers: a highly efficient photoelectrocatalyst towards degradation of tetracycline
Authors: Li Kang , Pang Yingping , Lu Qifang
Published: September 2019

Copper(ii) phthalocyanine-sensitized electrospun CeO2/Bi2MoO6 nanofibers (TNCuPc/CeO2/Bi2MoO6 nanofibers) were fabricated and applied as an efficient novel photocatalyst with enhanced photoelectrocatalytic activity.
A quinoline-based probe for effective and selective sensing of aspartic acid in aqueous medium: in vitro and in vivo live cell imaging
Authors: Elamathi C. , Butcher R. J. , Mohankumar A. , Sundararaj P. , Madankumar A. , Kalaivani P. , Prabhakaran R.
Published: September 2019

A highly sensitive and selective “on–off–on” chemosensor for aspartic acid in aqueous solution was established. In vitro live cell imaging against MCF 7 cells and in vivo imaging using C. elegans were successfully demonstrated.
Chiral-at-metal rhodium(iii) complex catalyzed enantioselective synthesis of C2-substituted benzofuran derivatives
Authors: Zhang Haoran , Li Shiwu , Kang Qiang , Du Yu
Published: September 2019

An enantioselective C2-nucleophilic functionalization of 3-aminobenzofurans has been realized under catalysis of chiral rhodium(iii) complexes, affording a large array of C2-substituted benzofuran derivatives in high yields and enantioselectivities.
Ultrathin nickel-metal–organic framework nanobelt based electrochemical sensor for the determination of urea in human body fluids
Authors: Bao Cancan , Niu Qiangqiang , Chen Zi-Ang , Cao Xiaowei , Wang Hui , Lu Wenbo
Published: September 2019

Ni-MOF ultrathin nanobelts in alkaline media can be used as an efficient catalyst for urea electrooxidation.
Electronic structures of bent lanthanide(III) complexes with two N-donor ligands
Authors: Nicholas Hannah M. , Vonci Michele , Goodwin Conrad A. P. , Loo Song Wei , Murphy Siobhan R. , Cassim Daniel , Winpenny Richard E. P. , McInnes Eric J. L. , Chilton Nicholas F. , Mills David P.
Published: September 2019

Halide abstraction chemistry is performed on a series of trigonal lanthanide(III) complexes to provide bent complexes that contain only two N-donor ligands.
Estimating the galaxy two-point correlation function using a split random catalog
Authors: Keihänen E. , Kurki-Suonio H. , Lindholm V. , Viitanen A. , Suur-Uski A.-S. , Allevato V. , Branchini E. , Marulli F. , Norberg P. , Tavagnacco D. , de la Torre S. , Valiviita J. , Viel M. , Bel J. , Frailis M. , Sánchez A. G.
Published: September 2019

The two-point correlation function of the galaxy distribution is a key cosmological observable that allows us to constrain the dynamical and geometrical state of our Universe. To measure the correlation function we need to know both the galaxy positions and the expected galaxy density field. The expected field is commonly specified using a Monte-Carlo sampling of the volume covered by the survey and, to minimize additional sampling errors, this random catalog has to be much larger than the data catalog. Correlation function estimators compare data–data pair counts to data–random and random–random pair counts, where random–random pairs usually dominate the computational cost. Future redshift surveys will deliver spectroscopic catalogs of tens of millions of galaxies. Given the large number of random objects required to guarantee sub-percent accuracy, it is of paramount importance to improve the efficiency of the algorithm without degrading its precision. We show both analytically and numerically that splitting the random catalog into a number of subcatalogs of the same size as the data catalog when calculating random–random pairs and excluding pairs across different subcatalogs provides the optimal error at fixed computational cost. For a random catalog fifty times larger than the data catalog, this reduces the computation time by a factor of more than ten without affecting estimator variance or bias.
Importance des microARN cellulaires dans la régulation des infections virales
Authors: López Paula , Girardi Erika , Pfeffer Sébastien
Published: September 2019

Parasites intracellulaires obligatoires, les virus dépendent d’un grand nombre de facteurs cellulaires pour accomplir leur cycle de multiplication. Parmi ceux-ci, les microARN (miARN) ont récemment émergé comme d’importants modulateurs des infections virales. Ces petites molécules régulatrices agissent comme des répresseurs de l’expression des gènes. Au cours de l’infection, ils peuvent agir sur des ARN cibles d’origine cellulaire mais aussi virale. Cette synthèse fait le point sur les différents mécanismes, directs et indirects, impliquant ces miARN dans la régulation des virus et aborde les possibles applications thérapeutiques qui peuvent en découler.
Les pièges de l’amélioration
Authors: Jordan Bertrand
Published: September 2019

Inactivation of the CCR5 gene by CRISPR editing in human embryos, as recently attempted in China, was touted as a positive change for the babies involved since it was expected to impart resistance to HIV infection. However, it turns out that the absence of CCR5 is not neutral but actually decreases fitness, as shown by survival analysis of population data in the UK biobank. This underlines the pitfalls of genetic enhancement, and emphasizes that any germline modification must be preceded by in-depth studies to exclude unforeseen negative effects. ‡
Arthrodesis of the Infected Knee Joint with the Ilizarov External Fixator: an Analysis of 13 Cases
Authors: Reinke Charlotte , Bäcker Hinnerk , Lotzien Sebastian , Schildhauer Thomas A. , Seybold Dominik , Gessmann Jan
Published: September 2019

Background Knee joint infections with pronounced joint destruction, soft tissue and bone involvement are serious diseases in which not only the joint but also the entire extremity are directly endangered. What results can be achieved with the Ilizarov external fixator for septic knee arthrodesis?

Patients and Methods Between 2005 and 2017, 13 patients (4 women and 9 men, mean age 46 years) with acute joint and concomitant bone and soft-tissue infections were treated with Ilizarov knee joint arthrodesis. In addition to demographic data, the time spent in the fixator, major and minor complications were retrospectively evaluated.

Results The average time spent in the Ilizarov external fixator was 27 weeks (min. 13, max. 68). Arthrodesis and infection repair were primarily achieved in 12 out of 13 patients. In one patient, a delayed healing of the arthrodesis zone could be cured by iliac crest bone grafting, so that eventually a bony knee arthrodesis was achieved in all patients. Pin infects as a minor complication during the time spent in the fixator were common and could be treated by stab incision and antibiotics. Major complications occurred in 3 cases (2 femoral fractures peri-implant, 1 nonunion in the arthrodesis area), which were treated by dilatation of the Ilizarov external fixator and finally plate osteosynthesis or by resection of the pseudarthrosis and iliac crest bone grafting.

Conclusion The knee joint arthrodesis with the Ilizarov external fixator is a salvage procedure for limb preservation in fulminant knee joint and concomitant soft tissue infections. The advantages lie in the possibility of osteosynthesis in the acute infection and/or chronic osteomyelitis and the direct full load capacity. Disadvantages are long and complicated treatment times in the fixator with limited patient comfort.
Infectious Myelitis
Authors: Asundi Archana , Cervantes-Arslanian Anna M. , Lin Nina H. , Barbosa Felipe
Published: September 2019

Myelitis refers to inflammation of the spinal cord which can result in a spectrum of neurologic impairment. Infectious pathogens are an important etiologic category, and can result in myelitis through direct pathogenic effect or through immune-mediated parainfection; this review focuses on the former category. The spectrum of clinical manifestations is summarized and a diagnostic workup provided to aid clinicians in developing an approach to patients presenting with symptoms suggestive of infectious myelitis. This is followed by an overview of the important viral, bacterial, parasitic, and fungal causes of infectious myelitis. The typical presentations, diagnostic modalities, and treatment approaches are outlined for key pathogens culprit in infectious myelitis to allow clinicians to promptly recognize and diagnose specific infectious etiologies of myelitis.
A Randomized Controlled Single-Blind Study Demonstrating Superiority of Amniotic Suspension Allograft Injection Over Hyaluronic Acid and Saline Control for Modification of Knee Osteoarthritis Symptoms
Authors: Farr Jack , Gomoll Andreas H. , Yanke Adam B. , Strauss Eric J. , Mowry Katie C. ,   ASA Study Group
Published: September 2019

Placental-derived tissues are a known source of anti-inflammatory and immune modulating factors. Published pilot data on amniotic suspension allograft (ASA) for the treatment of osteoarthritis (OA) demonstrated safety and trends for improved pain and function. A multicenter randomized controlled trial was designed to evaluate the efficacy of symptom modulation with ASA compared with saline and hyaluronic acid (HA) in subjects with knee OA. A total of 200 subjects were randomized 1:1:1 to ASA, HA, or saline, with subjects blinded to their allocation. Changes from baseline of patient-reported outcomes (PROs)—EQ-5D-5L, Knee Osteoarthritis Outcome Score (KOOS), visual analog scale (VAS), Tegner, and Single Assessment Numerical Evaluation (SANE)—were compared between groups. Patients reporting unacceptable pain at 3 months were considered treatment failures and withdrawn from the study. Statistical analysis was completed by comparing changes in PROs from baseline to 3 and 6 months for all groups. Comparison of demographics between treatment groups showed no significant differences between groups. Patients reporting unacceptable pain at 3 months in each group were ASA (13.2%), HA (68.8%), and saline (75%). Patients receiving ASA demonstrated significantly greater improvements from baseline for overall pain (VAS), KOOS pain, and KOOS-activities of daily living scores compared with those in the HA group (3 months) and both groups (6 months). ASA patients had significantly greater improvements in KOOS symptom scores compared with HA and saline at 3 and 6 months, respectively. OMERACT-OARSI responder rates for ASA, HA, and saline groups were 69.1, 39.1, and 42.6%, respectively (p = 0.0007). Subjects receiving ASA treatment showed greater improvements in PROs and fewer patients reported unacceptable pain compared with HA and saline. The evidence presented in this Level I Randomized Controlled Trial suggests that ASA injection is an effective treatment for the nonoperative management of symptomatic knee OA.
A unified modeling of wave mixing processes with the ray tracing method
Authors: Debayle A. , Ruyer C. , Morice O. , Masson-Laborde P.-E. , Loiseau P. , Benisti D.
Published: September 2019

The stationary ray tracing method, commonly used in hydrodynamic codes to describe the laser propagation and energy deposition, is reformulated to include energy exchanges between laser beams, referred to as cross-beam energy transfer (CBET), as well as laser beam backscatterings from acoustic (Brillouin) and electron (Raman) plasma waves. These energy exchanges and scatterings are described by a Monte Carlo method simulating the creation/annihilation of rays. The algorithm has been validated against other numerical solvers and, in the case of CBET, by means of kinetic simulations. The method is efficient and can be easily implemented in already existing ray tracing packages used in many hydrodynamic codes. It can be further extended to describe other kinds of wave mixing processes such as side-scatterings and collective scatterings.
Structural stability and mechanical property of Fe-W solid solutions from a constructed Fe-W potential
Authors: Mi S. T. , Gong H. R. , Fan J. L.
Published: September 2019

An Fe-W potential has been constructed by means of the embedded-atom method and has proven to be more realistic than the three published Fe-W potentials in the literature. Based on the constructed Fe-W potential, molecular dynamic simulation has been used to reveal structural stability, thermodynamic properties, and mechanical properties of BCC Fe-W solid solutions within the entire composition range. It is found that the Fe-W interaction in BCC Fe-W solid solutions should be weak and attractive with small and negative heats of formation, which agree well with those from the thermodynamic Miedema model and could clarify the controversy regarding heats of formation of Fe-W solid solutions in the literature. In addition, the derived coefficient of thermal expansion, heat capacity, elastic constants, and elastic moduli of Fe-W solid solutions from the present Fe-W potential are in good agreement with the corresponding data from ab initio calculation or experiments in the literature.
Theory of statistics of ties, loops, and tails in semicrystalline polymers
Authors: Adhikari Sabin , Muthukumar Murugappan
Published: September 2019

Polymer crystals grown from melts consist of alternating lamellar crystalline regions and amorphous regions. We study the statistics of ties: chains which bridge the adjacent lamellae, loops: chains which come out of one lamella and enter back into the same lamella before reaching the other lamellae, and tails: chains which end in an amorphous region. We develop a theory to calculate the probabilities of formation of ties, loops, and tails with consideration of finite chain length and cooperative incorporation of a chain into multiple lamellae. The results of our numerical calculations based on a field-theoretic formalism show that the fraction of ties increases with increasing chain length, and it decreases with increasing interlamellar separation. In the limiting case of an infinite chain confined between only two walls, we recover the classical results of the gambler’s ruin model. We show that the density anomaly encountered in previous theories is avoided naturally in the present theory without forcing the majority of stems to form tight loops. The derived results on the probability of tie chains in the amorphous regions are pertinent to the mechanical properties of semicrystalline polymers.
Competition of magnetic ordering and spin-phonon coupling in multiferroic hexagonal YMn1−xCrxO3
Authors: Cui J. Y. , Zhang A. M. , Shi J. Y. , Cao H. F. , Wu X. S. , Zhang Y. M.
Published: September 2019

Hexagonal yttrium manganite (YMnO3) and chromium doped yttrium manganite (YMn1 – xCrxO3) were prepared by the solid-state method. X-ray diffraction and Raman scattering were combined to explore the structural characterization. Structural analysis illustrates that the lattice is compressed and the tilt of the MO5 (M = Cr or Mn) bipyramid is decreased with an increase in Cr3+ concentration, leading to declining frustration. Magnetic measurement suggests both weak ferromagnetic (FM) and antiferromagnetic (AFM) orderings enhanced with the growth of doping concentration. Enhanced weak FM ordering may arise from breaking of the superexchange interaction and introduction of the double-exchange interaction inside the layers, and the increased AFM ordering is attributed to the improved coupling between neighboring planes that resulted from the structural distortion. Spin-phonon coupling is discussed to confirm the enhanced coupling between interplane Mn3+ moments.
Ultrafast carrier and phonon dynamics in few-layer 2H–MoTe2
Authors: Chi Zhen , Chen Hailong , Zhao Qing , Weng Yu-Xiang
Published: September 2019

By using femtosecond pump-probe spectroscopy with broadband detection from near-infrared to midinfrared, the carrier and phonon dynamics in few-layer 2H–MoTe2 after ultrafast excitation have been investigated in detail. Immediately following the photoexcitation, an ultrafast relaxation of the generated hot carriers by releasing phonons is observed within hundreds of femtoseconds. The subsequent electron-hole recombination with a time constant of ∼1.5 ps is clearly identified and demonstrated to be mediated through a defect-assisted process. Furthermore, we confirm that the observed redshift of the exciton resonance energy on longer time scales arises from the ultrafast thermalization of the 2H–MoTe2 lattice caused by the transfer of electronic excitation to the phonon system. As a result, the thermalization dynamics of the lattice within 2 ps and the following cooling process of the phonon system on the 100 ps time scale are directly monitored.
A memristor-based transient chaotic neural network model and its application
Authors: Liu Y. A. , Yu Q. , Hu S. G. , Qiao G. C. , Liu Y.
Published: September 2019

Transient chaotic neural networks (TCNNs) have shown promise in solving optimization problems but still suffer from slow convergence and being difficult to implement in hardware. In this paper, the HP memristor is introduced to a TCNN to develop a memristor-based transient chaotic neural network (MTCNN) model that is highly efficient, converges quickly, and has significant prospects for physical implementation. The proposed MTCNN makes full use of the nonlinearity and memory-related characteristics of memristors, and their conductance values are used as self-feedback connection weights that can be adjusted dynamically according to the annealing algorithm. The MTCNN model was applied to solve combinatorial optimization problems, including the channel assignment problem (CAP) of four cells and the traveling salesman problem (TSP) of 10 cities. In 500 runs, the MTCNN algorithm delivered a 5% higher optimal solution rate than the TCNN algorithm while using only 70% of its number of iterations in the CAP, and achieved a shorter average distance and a 40% higher convergence speed than the TCNN algorithm in the TSP.
Tuning the superconducting transition of SrTiO3-based 2DEGs with light
Authors: Arnold D. , Fuchs D. , Wolff K. , Schäfer R.
Published: September 2019

The resistivity of the two dimensional electron gas that forms at the interface of strontium titanate with various oxides is sensitive to irradiation from visible light. In this letter, we present data on the interface between the bandgap insulators LaAlO3 (LAO) and SrTiO3 (STO). We operate a light emitting diode at temperatures below 1 K and utilize it to irradiate the LAO/STO interface at ultralow temperatures. On irradiation, the resistance of this system is lowered continuously by a factor of five and the resistance change is persistent at low temperatures as long as the sample is kept in the dark. This makes the characterization of transport properties in different resistive states over extended time periods possible. Our pristine sample gets superconductive below 265 mK. The transition temperature Tc shifts downward on the persistent photo-induced lowering of the resistance. The persistent photoconductance can be completely reverted by heating the structure above 10 K, in which case, Tc takes on its original value. Thus, very similar to field-effect induced changes of the electron density, irradiation at low temperatures offers a versatile tuning knob for the superconducting state of STO-based interfaces which in addition has the advantage to be nonvolatile.
Extension distribution for DNA confined in a nanochannel near the Odijk regime
Authors: Chuang Hui-Min , Reifenberger Jeffrey G. , Bhandari Aditya Bikram , Dorfman Kevin D.
Published: September 2019

DNA confinement in a nanochannel typically is understood via mapping to the confinement of an equivalent neutral polymer by hard walls. This model has proven to be effective for confinement in relatively large channels where hairpin formation is frequent. An analysis of existing experimental data for Escherichia coli DNA extension in channels smaller than the persistence length, combined with an additional dataset for λ-DNA confined in a 34 nm wide channel, reveals a breakdown in this approach as the channel size approaches the Odijk regime of strong confinement. In particular, the predicted extension distribution obtained from the asymptotic solution to the weakly correlated telegraph model for a confined wormlike chain deviates significantly from the experimental distribution obtained for DNA confinement in the 34 nm channel, and the discrepancy cannot be resolved by treating the alignment fluctuations or the effective channel size as fitting parameters. We posit that the DNA-wall electrostatic interactions, which are sensible throughout a significant fraction of the channel cross section in the Odijk regime, are the source of the disagreement between theory and experiment. Dimensional analysis of the wormlike chain propagator in channel confinement reveals the importance of a dimensionless parameter, reflecting the magnitude of the DNA-wall electrostatic interactions relative to thermal energy, which has not been considered explicitly in the prevailing theories for DNA confinement in a nanochannel.
Sponge-templated production of ultra-thin ZnO nanosheets for printed ultraviolet photodetectors
Authors: Guo Qinglei , Zhao Yuting , Wang Gang , Chen Da , Zhao Haonan , Jiang Chengming , Huang Gaoshan , Di Zengfeng , Mei Yongfeng
Published: September 2019

This paper describes a simple and convenient approach to synthesize large amounts of ZnO nanosheets, which are suitable for producing a key component, i.e., colloidal nanoink, of printed ultraviolet photodetectors. ZnO nanosheets are produced by atomic layer deposition, where a three-dimensional polymer sponge with a large specific surface area is used as the template. Systematic studies including scanning electron microscopy, X-ray diffraction, and transmission electron microscopy reveal that the synthesized ZnO nanosheets have a good crystalline quality and mechanical flexibility. After dispersing ZnO nanosheets in a solvent to form a stable and colloidal nanoink, an ultraviolet photodetector is demonstrated through the printing method. Such a printed ultraviolet photodetector that utilizes ZnO nanosheets as the functional materials exhibits a high responsivity of ∼148 A/W and a response time of 19 s. Our present study may provide a practical method to produce large amounts of functional nanosheets for printing electronics, which paves the way for developing high-performance, low-cost, large-area printed, and flexible electronics.
Development of a questionnaire to assess listening difficulties in adults with auditory processing disorder
Authors: Obuchi Chie , Kaga Kimitaka
Published: September 2019

Purpose:

There are many requirements to assess and support individuals with auditory processing disorder (APD); however, there are a few questionnaires that can be employed to detect the listening difficulties experienced by adults who are suspected to have APD. In the present study, we developed a questionnaire to assess the specific listening difficulties of adults and examined the possibility of standardizing this questionnaire in clinical situations.

Method:

This study included 164 APD adults who had normal hearing, but who complained about listening difficulties encountered during everyday life, and 70 adults who had normal hearing and no complaints about listening difficulties during everyday life. We added four items of the psychological domain to the shortened versions of the Speech, Spatial, and Qualities of Hearing Scale (SSQ-12) for the purpose of assessing the psychological and social reactions to listening difficulties, and we administered it to subjects.

Results:

The results demonstrated that the questionnaire was a highly sensitive and specific approach and that it was useful in assessing adults with and without APD. This tendency especially increased by combining questions from the SSQ-12 with the psychological domain questions.

Conclusion:

We suggest that the questionnaire would be used to screen patients in clinical situations and that the results would provide useful information that can aid in understanding the auditory characteristics of people with APD.
Quantifying the magic of quantum channels
Authors: Wang Xin , Wilde Mark M , Su Yuan
Published: September 2019

To achieve universal quantum computation via general fault-tolerant schemes, stabilizer operations must be supplemented with other non-stabilizer quantum resources. Motivated by this necessity, we develop a resource theory for magic quantum channels to characterize and quantify the quantum ‘magic’ or non-stabilizerness of noisy quantum circuits. For qudit quantum computing with odd dimension d, it is known that quantum states with non-negative Wigner function can be efficiently simulated classically. First, inspired by this observation, we introduce a resource theory based on completely positive-Wigner-preserving quantum operations as free operations, and we show that they can be efficiently simulated via a classical algorithm. Second, we introduce two efficiently computable magic measures for quantum channels, called the mana and thauma of a quantum channel. As applications, we show that these measures not only provide fundamental limits on the distillable magic of quantum channels, but they also lead to lower bounds for the task of synthesizing non-Clifford gates. Third, we propose a classical algorithm for simulating noisy quantum circuits, whose sample complexity can be quantified by the mana of a quantum channel. We further show that this algorithm can outperform another approach for simulating noisy quantum circuits, based on channel robustness. Finally, we explore the threshold of non-stabilizerness for basic quantum circuits under depolarizing noise.
Universality of quantum diffractive collisions and the quantum pressure standard
Authors: Booth James L , Shen Pinrui , Krems Roman V , Madison Kirk W
Published: September 2019

This work demonstrates that quantum diffractive collisions are governed by a universal law characterized by a single parameter that can be determined experimentally. Specifically, we report a quantitative form of the universal, cumulative energy distribution transferred to initially stationary sensor particles by quantum diffractive collisions. The characteristic energy scale corresponds to the localization length associated with the collision-induced quantum measurement, and the shape of the universal function is determined only by the analytic form of the interaction potential at long range. Using cold 87Rb sensor atoms confined in a magnetic trap, we observe experimentally

p

QDU
6

, the universal function specific to van der Waals collisions, and use it to realize a self-defining particle pressure sensor that can be used for any ambient gas. This provides the first primary and quantum definition of the Pascal, applicable to any species and therefore represents a fundamental advance for vacuum and pressure metrology. The quantum pressure standard realized here is compared with a state-of-the-art orifice flow standard transferred by an ionization gauge calibrated for N2. The pressure measurements agree at the 0.5% level.
Temperature dependence of structural, dynamical, and electronic properties of amorphous Bi2Te3: an ab initio study
Authors: Guo Y R , Qiao Chong , Wang J J , Shen H , Wang S Y , Zheng Y X , Zhang R J , Chen L Y , Su Wan-Sheng , Wang C Z , Ho K M
Published: September 2019

Bismuth telluride (Bi2Te3) has garnered significant interest in thermoelectric applications and three-dimensional topological insulators due to its unique electronic, transport, and thermal properties. Bi2Te3 and Sb2Te3 chalcogenide compounds have the same crystal structure. While Sb2Te3 has been shown to be a prototypical phase change memory (PCM) compound along the pseudobinary tie-line of Ge-Sb-Te alloys, whether Bi2Te3 can also exhibit PCM functionality is still not well established. In this work, a systematic study on the structural, dynamical, and electronic properties of amorphous Bi2Te3 during the quenching process has been performed by using ab initio molecular dynamics simulations. Pair correlation function, coordination number, bond-angle distribution functions, and a novel atomistic cluster alignment method are used to explore the structural characteristics of Bi2Te3 as a function of temperature. Our study shows that there are many distorted octahedral clusters in amorphous Bi2Te3. In comparison with the local structures in Sb2Te3, we found that the degree of distortion of the octahedrons in the Bi2Te3 system is smaller than that in Sb2Te3 system. Moreover, the changes in the dynamical properties of Bi2Te3 from liquid to glassy state are also explored. The approximate range of liquid-to-glass transition temperature is determined to be between 673 and 723 K. The electronic properties of Bi2Te3 and Sb2Te3 are also analysed by density-of-states and Bader charge calculations, both of them in glass state are semiconductors. Our studies provide useful insights into the local structure and dynamical properties of Bi2Te3 at the atomistic level during the fast cooling process, and suggest that the compound can be a candidate for PCM materials.
A new quench detection method for HTS magnets: stray-capacitance change monitoring
Authors: Ravaioli E , Davis D , Marchevsky M , Sabbi GL , Shen T , Verweij A , Zhang K
Published: September 2019

Fast quench detection is a key requirement for the successful implementation of superconducting magnet technology. In high temperature superconductor magnets, this issue is especially challenging due to the low quench propagation velocity, and presently represents one of the main factors limiting their application. A new detection technique based on stray-capacitance monitoring is proposed. The capacitance between electrically-insulated magnet elements, such as magnet structure and end parts, is utilized as an indication of local heat deposition in the conductor. In fact, the relative permittivity of helium drops when it changes from the liquid to the gaseous phase. Thus, when heating occurs, part of the helium impregnating the insulation layers boils off, and the monitored stray-capacitance decreases. The proposed technique is successfully demonstrated on three small-scale Bi-2212 magnets manufactured at the Lawrence Berkeley National Laboratory. Results from the detection of thermal runaways and spot-heater induced quenches are reported and discussed. Advantages and limitations of the stray-capacitance method with respect to conventional quench detection methods are assessed.
Hunting down the ohmic contact of organic field-effect transistor*
Authors: Micjan M , Novota M , Telek P , Donoval M , Weis M
Published: September 2019

We report properties of contact resistances observed on pentacene organic field-effect transistors (OFET) with four different source/drain electrodes, namely, copper (Cu), gold (Au), silver (Ag), and germanium (Ge). The metals were selected to provide a wide range of energy barriers for charge injection, from blocking contact to smooth injection. All OFETs exhibited strong voltage dependence of the contact resistance, even for devices with smooth injection, which is in strong disagreement with the definition of ohmic contacts. A comparison with current crowding, resistive network, Fowler–Nordheim tunneling, and electric field enhanced thermionic injection (Schottky emission) pointed to importance of local electric fields and/or electrostatic field charges.
Trajectory equation of a lump before and after collision with line, lump, and breather waves for (2+1)-dimensional Kadomtsev–Petviashvili equation*
Authors: Zhang Zhao , Yang Xiangyu , Li Wentao , Li Biao
Published: September 2019

Based on the hybrid solutions to (2+1)-dimensional Kadomtsev–Petviashvili (KP) equation, the motion trajectory of the solutions to KP equation is further studied. We obtain trajectory equation of a single lump before and after collision with line, lump, and breather waves by approximating solutions of KP equation along some parallel orbits at infinity. We derive the mathematical expression of the phase change before and after the collision of a lump wave. At the same time, we give some collision plots to reveal the obvious phase change. Our method proposed to find the trajectory equation of a lump wave can be applied to other (2+1)-dimensional integrable equations. The results expand the understanding of lump, breather, and hybrid solutions in soliton theory.
Low drift nuclear spin gyroscope with probe light intensity error suppression*
Authors: Fan Wenfeng , Quan Wei , Liu Feng , Duan Lihong , Liu Gang
Published: September 2019

A nuclear spin gyroscope based on an alkali-metal–noble-gas co-magnetometer operated in spin-exchange relaxation-free (SERF) regime is a promising atomic rotation sensor for its ultra-high fundamental sensitivity. However, the fluctuation of probe light intensity is one of the main technical error sources that limits the bias stability of the gyroscope. Here we propose a novel method to suppress the bias error induced by probe light intensity fluctuations. This method is based on the inherent magnetic field response characteristics of the gyroscope. By the application of a bias magnetic field, the gyroscope can be tuned to a working point where the output signal is insensitive to probe light intensity variation, referred to herein as ‘zero point’, thus the bias error induced by intensity fluctuations can be completely suppressed. The superiority of the method was verified on a K–Rb–21Ne co-magnetometer, and a bias stability of approximately 0.01 °/h was obtained. In addition, the method proposed here can remove the requirement of the closed-loop control of probe light intensity, thereby facilitating miniaturization of the gyroscope volume and improvement of reliability.
The origin of distorted intensity pattern sensed by a lens and antenna coupled AlGaN/GaN-HEMT terahertz detector*
Authors: Li Xiang , Sun Jian-Dong , Huang Hong-Juan , Zhang Zhi-Peng , Jin Lin , Sun Yun-Fei , Popov V V , Qin Hua
Published: September 2019

Antenna-coupled field-effect-transistors (FETs) offer high sensitivity for terahertz detection. Both the magnitude and the polarity of the response signal are sensitive to the localized terahertz field under the gate. The ability of accurate sensing the intensity pattern is required for terahertz imaging systems. Here, we report artefacts in the intensity pattern of a focused terahertz beam around 1 THz by scanning a silicon-lens and antenna coupled AlGaN/GaN high-electron-mobility-transistor (HEMT) detector. The origin of the image distortion is found to be connected with one of the antenna blocks by probing the localized photocurrents as a function of the beam location and the frequency. Although the exact distortion is found with our specific antenna design, we believe similar artefacts could be commonplace in antenna-coupled FET terahertz detectors when the beam spot becomes comparable with the antenna size. To eliminate such artefacts, new antenna designs are welcomed to achieve strong asymmetry in the terahertz field distribution under the gate while maintaining a more symmetric radiation pattern for the whole antenna.
Experimental implementation of a continuous-time quantum random walk on a solid-state quantum information processor*
Authors: Tusun Maimaitiyiming , Wu Yang , Liu Wenquan , Rong Xing , Du Jiangfeng
Published: September 2019

There are some problems that quantum computers seem to be exponentially faster than classical computers, like factoring large numbers, machine learning, and simulation of quantum systems. Constructing an appropriate quantum algorithm becomes more important for solving these specific problems. In principle, any quantum algorithm can recast by a quantum random walk algorithm. Although quantum random walk with a few qubits has been implemented in a variety of systems, the experimental demonstration of solid-state quantum random walk remains elusive. Here we report the experimental implementation of the quantum continuous-time random walk algorithm by a two-qubit quantum processor in a nitrogen–vacancy center in diamond. We found that quantum random walk on a circle does not converge to any stationary distribution and exhibit a reversible property. Our results represent a further investigation of quantum walking dynamics in solid spin platforms, may also lead to other practical applications by the use of quantum continuous-time random walk for quantum algorithm design and quantum coherence transport.
High birefringence, low loss, and flattened dispersion photonic crystal fiber for terahertz application*
Authors: Wang Dou-Dou , Mu Chang-Long , Kong De-Peng , Guo Chen-Yu
Published: September 2019

A type of photonic crystal fiber based on Kagome lattice cladding and slot air holes in a rectangular core is investigated. Full vector finite element method is used to evaluate the modal and propagation properties of the designed fiber. High birefringence of 0.089 and low effective material loss of 0.055 cm−1 are obtained at 1 THz. The y-polarized fundamental mode of the designed fiber shows a flattened and near-zero dispersion of 0 ± 0.45 ps · THz−1 · cm−1 within a broad frequency range (0.5 THz–1.5 THz). Our results provide the theory basis for applications of the designed fiber in terahertz polarization maintaining systems.
High-magnetic-field induced charge order in high-Tc cuprate superconductors*
Authors: Zheng L X , Li J , Wu T
Published: September 2019

In the last few years, charge order and its entanglement with superconductivity are under hot debate in high-T
c community due to the new progress on charge order in high-T
c cuprate superconductors YBa2Cu3O6+x
. Here, we will briefly introduce the experimental status of this field and mainly focus on the experimental progress of high-field nuclear magnetic resonance (NMR) study on charge order in YBa2Cu3O6+x
. The pioneering high-field NMR work in YBa2Cu3O6+x
sets a new stage for studying charge order which has become a ubiquitous phenomenon in high-T
c cuprate superconductors.
Chemical vapor deposition growth of crystal monolayer SnS2with NaCl-assistant*
Authors: Liu Xiao-Xu , He Da-Wei , He Jia-Qi , Wang Yong-Sheng , Fu Ming
Published: September 2019

As an important member of the two-dimensional layers of metal dichalcogenides family, the two-dimensional (2D) group IV metal chalcogenides (GIVMCs) have been attracting intensive attention. However, the growth of monolayer tin disulfide (SnS2) remains a great challenge contrasted to transition metal dichalcogenides, which have been studied quite maturely. Till date, there have been scant reports on the growth of large-scale and large-size monolayer SnS2. Here, we successfully synthesized monolayer SnS2crystal on SiO2/Si substrates via NaCl-assisted CVD and the edge can be as long as 80 μm. Optical microscope, Raman spectroscopy, x-ray diffraction, atomic force microscopy (AFM), and energy-dispersion x-ray (EDX) were performed respectively to investigate the morphology, crystallographic structure, and optical property of the 2D SnS2nanosheets. In addition, we discussed the growing mechanism of the NaCl-assisted CVD method.
Giant enhancement of superconductivity in few layers MoTe2*
Authors: Gan Yuan , Cho Chang-Woo , Li Alei , Lyu Jian , Du Xu , Wen Jin-Sheng , Zhang Li-Yuan
Published: September 2019

Recently, the layered transition metal dichalcogenide 1T′ MoTe2 has attracted considerable attention due to its non-saturating magnetoresistance, type-II Weyl semimetal properties, superconductivity, and potential candidate for two-dimensional (2D) topological insulator in the single- and few-layer limit. Here in this work, we perform systematic transport measurements on thin flakes of MoTe2 prepared by mechanical exfoliation. We find that MoTe2 flakes are superconducting and have an onset superconducting transition temperature T
c up to 5.3 K, which significantly exceeds that of its bulk counterpart. The in-plane upper critical field (H

c2||) is much higher than the Pauli paramagnetic limit, implying that the MoTe2 flakes have Zeeman-protected Ising superconductivity. Furthermore, the T
c and H

c2 can be tuned by up to 320 mK and 400 mT by applying a gate voltage. Our result indicates that MoTe2 flake is a good candidate for studying exotic superconductivity with nontrivial topological properties.
Electro-optomechanical switch via tunable bistability and four-wave mixing
Authors: Ullah Kamran
Published: September 2019

We investigate the tunable bistable behavior of a hybrid nano-electro-optomechanical system (NEOMS) composed of S-shaped in the presence of two-level atoms, trapped inside a Fabry–Pérot cavity, and driven by a strong driving field and a weak probe field. The bistable behavior of the steady-state photon number and the mechanical steady-state positions are discussed. Further, we tune bistability by tuning all the coupling frequencies involved in the system and amplitude of the driving field. The present study provides the possibility of realization of a controllable optical switch depending on atom-field coupling, optomechanical coupling, electrostatic Coulomb coupling, and threshold power. In addition, we discuss that the non-linear effect of the hybrid NEOMS generates the four-wave mixing (FWM) process. Moreover, we show that the FWM process can be suppressed by the atom-field detuning and cavity-field detuning, which exhibits low photon transmission.
Dislocation neutralizing in a self-organized array of dislocation and anti-dislocation*
Authors: Deng Feng-Lin , Hu Xiang-Sheng , Wang Shao-Feng
Published: September 2019

A one-dimensional (1D) self-organized array composed of dislocation and anti-dislocation is analytically investigated in the frame of Peierls theory. From the exact solution of the Peierls equation, it is found that there exists strong neutralizing effect that makes the Burgers vector of each individual dislocation in the equilibrium array smaller than that of an isolated dislocation. This neutralizing effect is not negligible even though dislocations are well separated. For example, when the distance between the dislocation and the anti-dislocation is as large as ten times of the dislocation width, the actual Burgers vector is only about 80 % of an isolated dislocation. The neutralizing effect originates physically from the power-law asymptotic behavior that enables two dislocations interfere even though they are well separated.
Realization of the triple point of carbon dioxide evaluated by the ITS–90
Authors: Kawamura Yasuki , Matsumoto Nobuhiro , Nakano Tohru
Published: September 2019

We performed a precise temperature measurement of the triple point of carbon dioxide (CO2), which is one of the secondary reference points of the International Temperature Scale of 1990 (ITS–90), using an adiabatic calorimeter with five capsule-type standard platinum resistance thermometers (SPRTs). Impurity analyses showed that the purity of the CO2 sample was 99.999 37%. A thermal treatment process before the realization of the triple point reduced the width of the melting curve of the triple point of CO2 and increased the linearity of the melting curves with respect to the inverse of the melting fraction F. We determined the triple-point temperature of CO2 at the liquidus point by extrapolating the six melting curves obtained after the thermal treatment process. The triple-point temperature of CO2 measured in this work is 216.590 90 K

0.36 mK (k  =  1). This result indicates that the triple point of CO2 can potentially be used as a fixed point based on the ITS–90 to replace the triple point of mercury.
Calibration of free-space and fiber-coupled single-photon detectors*
Authors: Gerrits Thomas , Migdall Alan , Bienfang Joshua C , Lehman John , Nam Sae Woo , Splett Jolene , Vayshenker Igor , Wang Jack
Published: September 2019

We measure the detection efficiency of single-photon detectors at wavelengths near 851 nm and 1533.6 nm. We investigate the spatial uniformity of one free-space-coupled single-photon avalanche diode and present a comparison between fusion-spliced and connectorized fiber-coupled single-photon detectors. We find that our expanded relative uncertainty for a single measurement of the detection efficiency is as low as 0.70% for fiber-coupled measurements at 1533.6 nm and as high as 1.78% for our free-space characterization at 851.7 nm. The detection-efficiency determination includes corrections for afterpulsing, dark count, and count-rate effects of the single-photon detector with the detection efficiency interpolated to operation at a specified detected count rate.