bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and characterization of an Fe(i) cage complex with high stability towards strong H-acids
Authors: Voloshin Yan Z. , Novikov Valentin V. , Nelyubina Yulia V. , Belov Alexander S. , Roitershtein Dmitrii M. , Savitsky Anton , Mokhir Andriy , Sutter Jörg , Miehlich Matthias E. , Meyer Karsten
Published: January 2018

The new iron(i) dioximate showed an unrivaled stability towards strong acids. This calls for a reassessment of the electrocatalytic activity of similar low-valent Co and Fe cage complexes, which have shown to be effective HER electrocatalysts.
Ionic liquids in cross-coupling reactions: “liquid” solutions to a “solid” precipitation problem
Authors: Choudhary Hemant , Berton Paula , Gurau Gabriela , Myerson Allan S. , Rogers Robin D.
Published: January 2018

To alleviate the problem of solid salt precipitation when using inorganic bases in cross-coupling reactions, basic anions were combined with the trihexyl(tetradecyl)phosphonium ([P66614]+) cation to ensure an ionic liquid byproduct.
Origin of enhancement in Raman scattering from Ag-dressed carbon-nanotube antennas: experiment and modelling
Authors: Raziman T. V. , Duenas J. A. , Milne W. I. , Martin O. J. F. , Dawson P.
Published: January 2018

Isolating the role of global plasmonic response and local warm spots in Raman enhancement of silver-coated multi-walled carbon nanotubes.
An insight into the origin of room-temperature ferromagnetism in SnO2and Mn-doped SnO2quantum dots: an experimental and DFT approach
Authors: Manikandan Dhamodaran , Boukhvalov D. W. , Amirthapandian S. , Zhidkov I. S. , Kukharenko A. I. , Cholakh S. O. , Kurmaev E. Z. , Murugan Ramaswamy
Published: January 2018

Oxygen vacancies and multiple configurations of Mn (Mn2+and Mn3+) might be the cause of the observed room-temperature ferromagnetism in SnO2QDs.
Cl-Loss dynamics in the dissociative photoionization of CF3Cl with threshold photoelectron–photoion coincidence imaging
Authors: Wu Xiangkun , Tang Guoqiang , Zhang Hanhui , Zhou Xiaoguo , Liu Shilin , Liu Fuyi , Sheng Liusi , Yan Bing
Published: January 2018

Cl-loss dynamics in the dissociative photoionization of CF3Cl was investigated in the photon energy range of 12.30–18.50 eV.
Lifetime eco-nanotoxicology in an adult organism: where and when is the invertebrate C. elegans vulnerable?
Authors: von Mikecz Anna
Published: January 2018

This review addresses nanotoxicology in the nematode roundworm Caenorhabditis elegans throughout its entire life span, premature functional aging of the target organs and ecological considerations.
Inertial-ordering-assisted droplet microfluidics for high-throughput single-cell RNA-sequencing
Authors: Moon Hui-Sung , Je Kwanghwi , Min Jae-Woong , Park Donghyun , Han Kyung-Yeon , Shin Seung-Ho , Park Woong-Yang , Yoo Chang Eun , Kim Shin-Hyun
Published: January 2018

We developed a modified high-throughput droplet barcoding technique for single-cell Drop-Seq via introduction of hydrodynamic ordering in a spiral microchannel.
Chemical coatings relying on the self-polymerization of catechol for retrievable vena cava filters
Authors: Bao Songhao , Kang Jialin , Tu Chengzhao , Xu Chengfeng , Ye Lin , Zhang Huan , Zhao Hui , Zhang Aiying , Feng Zengguo , Zhang Fuxian
Published: January 2018

After covalent conjugation with catechol, heparin and paclitaxel can be chemically coated on a Ti–Ni alloy to endow anti-thrombosis and anti-intimal hyperplasia properties, respectively.
2D layered organic–inorganic heterostructures for clean energy applications
Authors: Azadmanjiri Jalal , Wang James , Berndt Christopher C. , Yu Aimin
Published: January 2018

2D layered organic–inorganic heterostructures are some of the most promising materials for a broad range of high-efficiency clean energy devices.
Mechanistic insights into the allosteric regulation of Pseudomonas aeruginosa aspartate kinase
Authors: Li Chang-Cheng , Yang Mei-Jia , Liu Li , Li Tao , Peng Cui-Ting , He Li-Hui , Song Ying-Jie , Zhu Yi-Bo , Shen Ya-Lin , Yang Jing , Zhao Ning-Lin , Zhao Chang , Zhou Qiao-Xia , Li Hong , Kang Mei , Tong Ai-Ping , Tang Hong , Bao Rui
Published: January 2018

In plants and microorganisms, aspartate kinase (AK) catalyzes an initial commitment step of the aspartate family amino acid biosynthesis. Owing to various structural organizations, AKs from different species show tremendous diversity and complex allosteric controls. We report the crystal structure of AK from Pseudomonas aeruginosa (PaAK), a typical α2β2 hetero-tetrameric enzyme, in complex with inhibitory effectors. Distinctive features of PaAK are revealed by structural and biochemical analyses. Essentially, the open conformation of Lys-/Thr-bound PaAK structure clarifies the inhibitory mechanism of α2β2-type AK. Moreover, the various inhibitory effectors of PaAK have been identified and a general amino acid effector motif of AK family is described.
The stellar content of the XMM-Newton slew survey
Authors: Freund S. , Robrade J. , Schneider P. C. , Schmitt J. H. M. M.
Published: January 2018

Aims. We present a detailed analysis of the stellar content of the current version of the XMM-Newton slew survey (XMMSL2).

Methods. Since stars emit only a small fraction of their total luminosity in the X-ray band, the stellar XMMSL2 sources ought to have relatively bright optical counterparts. Therefore the stellar identifications were obtained by an automatic crossmatch of the XMMSL2 catalog with the first Gaia data release (Gaia DR1), 2MASS, and Tycho2 catalogs. The reliability of this procedure was verified by a comparison with the individually classified Einstein Observatory medium sensitivity survey X-ray sources and by a crossmatch with the Chandra Source Catalog.

Results. We identify 6815 of the 23 252 unique XMMSL2 sources to be stellar sources, while 893 sources are flagged as unreliable. For every counterpart a matching probability is estimated based upon the distance between the XMMSL2 source and the counterpart. Given this matching probability the sample is expected to be reliable to 96.7 % and complete to 96.3 % . The sample contains stars of all spectral types and luminosity classes, and late-type dwarfs have the largest share. For many stellar sources the fractional contribution of the X-ray band to the total energy output is found above the saturation limit of previous studies (Lx/Lbol = 10−3), because the XMMSL2 sources are more affected by flares owing to their short exposure times of typically 6 s. A comparison with the second ROSAT all-sky survey (2RXS) source catalog shows that about 25 % of the stellar XMMSL2 sources are previously unknown X-ray sources. The results of our identification procedure can be accessed via VizieR.
The influence of drilling process automation on improvement of blasting works quality in open pit mining
Authors: Bodlak Maciej , Dmytryk Dominik , Mertuszka Piotr , Szumny Marcin , Tomkiewicz Grzegorz
Published: January 2018

The article describes the monitoring system of blasthole drilling process called HNS (Hole Navigation System), which was used in blasting works performed by Maxam Poland Ltd. Developed by Atlas Copco's, the HNS system – using satellite data – allows for a very accurate mapping of the designed grid of blastholes. The article presents the results of several conducted measurements of ground vibrations triggered by blasting, designed and performed using traditional technology and using the HNS system and shows first observations in this matter.
Analysis of rock mass dynamic impact influence on the operation of a powered roof support control system
Authors: Szurgacz Dawid , Brodny Jaroław
Published: January 2018

A powered roof support is a machine responsible for protection of an underground excavation against deformation generated by rock mass. In the case of dynamic impact of rock mass, the proper level of protection is hard to achieve. Therefore, the units of the roof support and its components are subject to detailed tests aimed at acquiring greater reliability, efficiency and efficacy. In the course of such test, however, it is not always possible to foresee values of load that may occur in actual conditions. The article presents a case of a dynamic load impacting the powered roof support during a high-energy tremor in an underground hard coal mine. The authors discuss the method for selecting powered roof support units proper for specific forecasted load conditions. The method takes into account the construction of the support and mining and geological conditions of an excavation. Moreover, the paper includes tests carried out on hydraulic legs and yield valves which were responsible for additional yielding of the support. Real loads impacting the support unit during tremors are analysed. The results indicated that the real registered values of the load were significantly greater than the forecasted values. The analysis results of roof support operation during dynamic impact generated by the rock mass (real life conditions) prompted the authors to develop a set of recommendations for manufacturers and users of powered roof supports. These include, inter alia, the need for innovative solutions for testing hydraulic section systems.
Analysis of conditions and the concept of multidirectional revitalization of the dolomite quarry in Siewierz
Authors: Pawełczyk Katarzyna
Published: January 2018

The development of mining of rock raw materials in Poland has significantly contributed to economic growth and the quality of life of local communities. However, mining activity, besides a number of positive effects, also implies broadly understood changes in the environment and the formation of brownfields. Reclamation and redevelopment of post-industrial areas, and especially post-mining areas, is currently a huge environmental and socio-economic challenge. Revitalization of post-mining areas is particularly important for small towns and municipalities, where mining was one of the main pillars of development and prosperity. An example of such a municipality is Siewierz in Silesian Voivodship. In the paper analysis the conditions have been conducted and the concept of revitalization of dolomite quarry Górnicze Zakłady Dolomitowe S.A. has been proposed. The AHP method has been used to analyse and select the optimal method of revitalization. As a result of the analysis, the concept of multidirectional revitalization with socially, economically and environmentally beneficial functions has been created, maximizing the potential of the quarry.
Primary law in medicine, its legal nature
Authors: Zarins K.
Published: January 2018

Thework will discuss the problems arising from the thesis that the economic opportunities are incompatible with the person's primary law - the right to life and equality of treatment. An actively maintained hypothesis claims that the country's economic opportunities and funding should not restrict or reduce a person's right to life and health. In this aspect, it will also study the role of the constitutional court.

The author points to the fact that the adoption of such, here the Supreme Court decision, successive constitutional court for a preliminary inaccurate claim and interpretation of the country's economic interests, could deny the right of people to life only after the consideration that they are of no use and financially expensive to be maintained.
Evaluation of healthcare policy in Latvia
Authors: Bikava I. , Skride A.
Published: January 2018

Performance of healthcare system of Latvia has been criticised for several years, due to the problems of accessibility, weak efficiency and insufficient funding. Politicians, foreign and local experts all agree upon the need of reforms to improve the performance of the healthcare system. The aims are defined in long-term policy documents, but there are no defined tasks to be made and aims to be achieved in mid-term and short-term policy.

The aim of the research was to make evaluation of performance of Latvia healthcare system as well as evaluation according to “Health 2020” framework recommendations.

The results showed that changes in the healthcare system in Latvia are made on ‘ad-hoc’ basis without a strategic long-term plan, and despite the fact that guidelines on the public health refear to “Health 2020”, the changes that are made and reforms that are planned are not in compliance with “Health 2020”. Work on social determinants (equity, universal coverage, accessibility) hasn’t been effective, the aim ‘health in all policies’ hasn’t been achieved and the primary healthcare due to its unaccessibility doesn’t provide expected efficiency in the whole healthcare system.
Adherence to treatment after CABG in terms of patients’ personality
Authors: Iakovleva M. , Shchelkova O. , Lubinskaya E. , Nikolaeva O.
Published: January 2018

The relevance of the problem is caused by the prevalence of cardiovascular diseases among the population, including coronary heart disease which requires surgical treatment, on the one hand, and low rates of treatment adherence among patients with chronic diseases, which reduce the effectiveness of the treatment and survival rates of patients, on the other hand. Patients after CABG were divided into groups according to the degree of their adherence to treatment and were examined by using the Big Five Questionnaire. Differences between the groups on the scales “conscientiousness” (p<0,001), “openness” (p<0,001), “agreeableness” (p<0,05), and “neuroticism” (p<0,05) were revealed. The study showed that the psychological factors are relevant in the definition of adherence to treatment and patients’ personality traits are potentially significant for the prediction of its degree among patients after CABG.
The role of cultural involvement of patients for their social welfare
Authors: Dromantiene L. , Staras K. , Uselyte M.
Published: January 2018

Cultural involvement takes a significant role on quality of life of patients (QoL) as namely culture is an important domain for health and QoL simultaneously. Paper analyzes the possible connection between culture and health, and, attendance of patients the cultural events as one of the important dimensions of QoL. Research is based on social project “Cultural prescription”, organized by public cultural institution “Mokytojų namai” (Eng. Teacher’s House) in Vilnius and dedicated to Outpatient Clinic “Centro poliklinika” (Vilnius) patients, who were suffering from chronic disease to improve their QoL. The aim of the paper is to explore the possibilities of innovative social measures to increase social cultural engagement of patients, to contribute to their well-being, and to present the approach of health care practitioners towards the expediency and usefulness of inter-sectorial cooperation for the patients’ social welfare.
Why the share of small amount pensions is so substantial in Latvia?
Authors: Rajevska O. , Rajevska F.
Published: January 2018

More than 70% of all old-age pensions in Latvia are smaller than 300 euro, which is close to the monetary value of the at-risk-of-poverty threshold. There is a number of reasons for it: the lack of non-contributory component and inadequately low minimum pensions, the absence of redistribution mechanisms in the mandatory notional defined contribution (pillar I) and funded (pillar II) schemes, an unfair conversion of pre-reform employment record into pension formula, and a high tax burden on pensioners. The authors proposed a package of measures to improve the situation: an introduction of basis pensions, linking minimum pensions to the country average wages, increasing income tax exempt for pensions, restoration of the supplements for pre-reform employment and their regular indexation, removal of the threshold in initial notional pension capital calculation or its reduction from 30 to 20 years.
Shaping effects on toroidal magnetohydrodynamic modes in the presence of plasma and wall resistivity
Authors: Rhodes Dov J. , Cole A. J. , Brennan D. P. , Finn J. M. , Li M. , Fitzpatrick R. , Mauel M. E. , Navratil G. A.
Published: January 2018

This study explores the effects of plasma shaping on magnetohydrodynamic mode stability and rotational stabilization in a tokamak, including both plasma and wall resistivity. Depending upon the plasma shape, safety factor, and distance from the wall, the β-limit for rotational stabilization is given by either the resistive-plasma ideal-wall (tearing mode) limit or the ideal-plasma resistive-wall (resistive wall mode) limit. In order to explore this broad parameter space, a sharp-boundary model is developed with a realistic geometry, resonant tearing surfaces, and a resistive wall. The β-limit achievable in the presence of stabilization by rigid plasma rotation, or by an equivalent feedback control with imaginary normal-field gain, is shown to peak at specific values of elongation and triangularity. It is shown that the optimal shaping with rotation typically coincides with transitions between tearing-dominated and wall-dominated mode behavior.
Suppression of persistent photo-conductance in solution-processed amorphous oxide thin-film transistors
Authors: Lee Minkyung , Kim Minho , Jo Jeong-Wan , Park Sung Kyu , Kim Yong-Hoon
Published: January 2018

This study offers a combinatorial approach for suppressing the persistent photo-conductance (PPC) characteristic in solution-processed amorphous oxide semiconductor (AOS) thin-film transistors (TFTs) in order to achieve rapid photo-recovery. Various analyses were used to examine the photo-instability of indium-gallium-zinc-oxide (IGZO) TFTs including negative-bias-illumination-stress (NBIS) and transient photo-response behaviors. It was found that the indium ratio in metallic components had a significant impact on their PPC and photo-recovery characteristics. In particular, when the indium ratio was low (51.5%), the PPC characteristic was significantly suppressed and achieving rapid photo-recovery was possible without significantly affecting the electrical performance of AOSs. These results imply that the optimization of the indium composition ratio may allow achieving highly photo-stable and near PPC-free characteristics while maintaining high electrical performance of AOSs. It is considered that the negligible PPC behavior and rapid photo-recovery observed in IGZO TFTs with a lower indium composition are attributed to the less activation energy required for the neutralization of ionized oxygen vacancies.
Self-consistent predictor/corrector algorithms for stable and efficient integration of the time-dependent Kohn-Sham equation
Authors: Zhu Ying , Herbert John M.
Published: January 2018

The “real time” formulation of time-dependent density functional theory (TDDFT) involves integration of the time-dependent Kohn-Sham (TDKS) equation in order to describe the time evolution of the electron density following a perturbation. This approach, which is complementary to the more traditional linear-response formulation of TDDFT, is more efficient for computation of broad-band spectra (including core-excited states) and for systems where the density of states is large. Integration of the TDKS equation is complicated by the time-dependent nature of the effective Hamiltonian, and we introduce several predictor/corrector algorithms to propagate the density matrix, one of which can be viewed as a self-consistent extension of the widely used modified-midpoint algorithm. The predictor/corrector algorithms facilitate larger time steps and are shown to be more efficient despite requiring more than one Fock build per time step, and furthermore can be used to detect a divergent simulation on-the-fly, which can then be halted or else the time step modified.
Experimental evidences of quantum confined 2D indirect excitons in single barrier GaAs/AlAs/GaAs heterostructure using photocapacitance at room temperature
Authors: Bhunia Amit , Singh Mohit Kumar , Galvão Gobato Y. , Henini Mohamed , Datta Shouvik
Published: January 2018

We investigated excitonic absorptions in a GaAs/AlAs/GaAs single barrier heterostructure using both photocapacitance and photocurrent spectroscopies at room temperature. Photocapacitance spectra show well defined resonance peaks of indirect excitons formed around the Γ-AlAs barrier. Unlike DC-photocurrent spectra, frequency dependent photocapacitance spectra interestingly red shift, sharpen up, and then decrease with increasing tunneling at higher biases. Such dissimilarities clearly point out that different exciton dynamics govern these two spectral measurements. We also argue why such quantum confined dipoles of indirect excitons can have thermodynamically finite probabilities to survive even at room temperature. Finally, our observations demonstrate that the photocapacitance technique, which was seldom used to detect excitons in the past, is useful for selective detection and experimental tuning of relatively small numbers (∼1011/cm2) of photo-generated indirect excitons having large effective dipole moments in this type of quasi-two dimensional heterostructures.
Simple relations for electron temperature and potential in dilute cold plasma flows
Authors: Zhang Kai , Cai Chunpei , Cooke David L.
Published: January 2018

This short note presents concise semi-analytical expressions for electron temperature and potential in unsteady dilute cold plasma flows. The analysis is based on the detailed fluid model for electrons. Ionizations and normalized electron number density gradients are neglected, and the transport properties are assumed as local constants. Flow is unsteady and Maxwell's equations are adopted in the analysis. With these treatments, the partial differential equations for unsteady electron temperature and potential degenerate as ordinary differential equations. Along an electron streamline, two simple formulas for unsteady electron temperature and plasma potential are obtained. These formulas offer some insights, for example, the electron temperature and plasma potential distributions along an electron streamline include two exponential functions: one for spatial distance along a streamline and the other for time.
Electron spin resonance study of surface and oxide interface spin-triplet centers on (100) silicon wafers
Authors: Saito H. , Hayashi S. , Kusano Y. , Itoh K. M. , Vlasenko M. P. , Vlasenko L. S.
Published: January 2018

Electron spin resonance (ESR) spectra of surface and interface recombination centers recently observed on (001) silicon wafers, labeled Pm and KU1, were studied using spin dependent microwave photoconductivity. Both ESR spectra, having the orthorhombic symmetry and spins S = 1/2 and S = 1 for Pm and KU1, respectively, were observed in the commercially available surface oxidized (001)-Si wafers. Systematic studies on annealing and oxidation conditions for the Pm and KU1 formation conclude that both ESR spectra arise from the same center that contains the interaction between the two nearest Si dangling bonds on the (001) Si surface.
Early stage aggregation of a coarse-grained model of polyglutamine
Authors: Haaga Jason , Gunton J. D. , Buckles C. Nadia , Rickman J. M.
Published: January 2018

In this paper, we study the early stages of aggregation of a model of polyglutamine (polyQ) for different repeat lengths (number of glutamine amino acid groups in the chain). In particular, we use the Large-scale Atomic/Molecular Massively Parallel Simulator to study a generic coarse-grained model proposed by Bereau and Deserno. We focus on the primary nucleation mechanism involved and find that our results for the initial self-assembly process are consistent with the two-dimensional classical nucleation theory of Kashchiev and Auer. More specifically, we find that with decreasing supersaturation, the oligomer fibril (protofibril) transforms from a one-dimensional β sheet to two-, three-, and higher layer β sheets as the critical nucleus size increases. We also show that the results are consistent with several predictions of their theory, including the dependence of the critical nucleus size on the supersaturation. Our results for the time dependence of the mass aggregation are in reasonable agreement with an approximate analytical solution of the filament theory by Knowles and collaborators that corresponds to an additional secondary nucleation arising from filament fragmentation. Finally, we study the dependence of the critical nucleus size on the repeat length of polyQ. We find that for the larger length polyglutamine chain that we study, the critical nucleus is a monomer, in agreement with experiment and in contrast to the case for the smaller chain, for which the smallest critical nucleus size is four.
Spectral effects in the propagation of chirped laser pulses in uniform underdense plasma
Authors: Pathak Naveen , Zhidkov Alexei , Hosokai Tomonao , Kodama Ryosuke
Published: January 2018

Propagation of linearly chirped and linearly polarized, powerful laser pulses in uniform underdense plasma with their duration exceeding the plasma wave wavelength is examined via 3D fully relativistic particle-in-cell simulations. Spectral evolution of chirped laser pulses, determined by Raman scattering, essentially depends on the nonlinear electron evacuation from the first wake bucket via modulation of the known parameter ne(r)ω02γ. Conversely, the relative motion of different spectral components inside a pulse changes the evolution of the pulse length and, therefore, the ponderomotive forces at the pulse rear. Such longitudinal dynamics of the pulse length provoke a parametric resonance in the laser wake with continuous electron self-injection for any chirped pulses. However, the total charge of accelerated electrons and their energy distribution essentially depends on the chirp. Besides, negatively chirped laser pulses are shown to be useful for spatially resolved measurements of the plasma density profiles and for rough estimations of the laser pulse intensity evolution in underdense plasma.
Electronic and magneto-transport in chirality sorted carbon nanotube films
Authors: Janas Dawid , Czechowski Nikodem , Adamus Zbigniew , Giżewski Tomasz
Published: January 2018

This research details electronic and magneto-transport in unsorted and chirality-enriched carbon nanotube (CNT) films. By measuring the electrical conductivity from 4 K to 297 K, we were able to assign the governing mechanism of electronic transport. Fluctuation-induced tunnelling was in accordance with the obtained data and very well matched the underlying physics. We demonstrated how a change in the type of CNT to make the film affects its electrical performance. As the temperature was decreased down to cryogenic conditions, up to a 56-fold increase in resistance was noted. Moreover, the measurement of magnetoresistance (MR) revealed a non-monotonic dependence on the applied magnetic field. The initial negative component of MR was eventually overpowered by the positive MR component as the field strength was increased beyond a certain threshold.
Piezospectroscopy and first-principles calculations of the nitrogen-vacancy center in gallium arsenide
Authors: Kovac Nicola , Künneth Christopher , Alt Hans Christian
Published: January 2018

The nitrogen-vacancy (NV) center occurs in GaAs bulk crystals doped or implanted with nitrogen. The local vibration of nitrogen gives rise to a sharp infrared absorption band at 638 cm–1, exhibiting a fine structure due to the different masses of neighboring 69Ga and 71Ga host isotopes. Piezospectroscopic investigations in the crystallographic ⟨100⟩ direction prove that the center has C3v point symmetry, which is weakly perturbed by the isotope effect. The stress-induced shifts of some band components show an unusual non-linear behavior that can be explained by coupling between the isotope and the stress splitting. First-principles density-functional theory calculations are in full accordance with the experiments and confirm the C3v symmetry, caused by relaxation of the nitrogen atom from the anion lattice site towards the nearest-neighbor Ga plane. Furthermore, the calculations indicate the –3 charge state of the center as the most stable one for nearly all Fermi level positions. The NV center in GaAs is structurally analogous to the same center in diamond.
Simulation of ultrafast bursts of subpicosecond pulses: In pursuit of efficiency
Authors: Povarnitsyn Mikhail E. , Levashov Pavel R. , Knyazev Dmitry V.
Published: January 2018

Using a hydrodynamic two-temperature model, we simulate multi-pulse laser ablation of an aluminum bulk target. The results of modeling demonstrate that the effectiveness of the multi-pulse ablation increases an order of magnitude in comparison to a single-pulse ablation of the same energy, while the repetition rate grows up to several GHz because the material surface does not cool down substantially between successive pulses. To prevent the shielding and suppression effects, the fluence of each pulse in the burst should have a subthreshold value to avoid the generation of slow moving ablated condensed-phase nanolayers. The obtained results are consistent with recent experiments on ablation by ultrafast bursts of ultrashort pulses.
Ab initio potential and rotational spectra of the CO–N2 complex
Authors: Surin L. A. , Tarabukin I. V. , Schlemmer S. , Kalugina Y. N. , van der Avoird A.
Published: January 2018

Ab initio calculations of the intermolecular potential energy surface (PES) of CO–N2 have been carried out using the closed-shell single- and double-excitation coupled cluster approach with a non-iterative perturbative treatment of triple excitations method and the augmented correlation-consistent quadruple-zeta (aug-cc-pVQZ) basis set supplemented with midbond functions. The global minimum (De = 117.35 cm−1) of the four-dimensional PES corresponds to an approximately T-shaped structure with the N2 subunit forming the leg and CO the top. The bound rovibrational levels of the CO–N2 complex were calculated for total angular momenta J = 0–8 on this intermolecular potential surface. The calculated dissociation energies D0 are 75.60 and 76.79 cm−1 for the ortho-N2 (A-symmetry) and para-N2 (B-symmetry) nuclear spin modifications of CO–N2, respectively. Guided by these bound state calculations, a new millimeter-wave survey for the CO–N2 complex in the frequency range of 110-145 GHz was performed using the intracavity OROTRON jet spectrometer. Transitions not previously observed were detected and assigned to the subbands connecting the K = 0 and 1, (jCO, jN2) = (1, 0) states with a new K = 1, (jCO, jN2) = (2, 0) state. Finally, the measured rotational energy levels of the CO–N2 complex were compared to the theoretical bound state results, thus providing a critical test of the quality of the PES presented. The computed rovibrational wave functions were analyzed to characterize the nature of the different bound states observed for the two nuclear spin species of CO–N2.
Determination of current and rotational transform profiles in a current-carrying stellarator using soft x-ray emissivity measurements
Authors: Ma X. , Cianciosa M. R. , Ennis D. A. , Hanson J. D. , Hartwell G. J. , Herfindal J. L. , Howell E. C. , Knowlton S. F. , Maurer D. A. , Traverso P. J.
Published: January 2018

Collimated soft X-ray (SXR) emissivity measurements from multi-channel cameras on the Compact Toroidal Hybrid (CTH) tokamak/torsatron device are incorporated in the 3D equilibrium reconstruction code V3FIT to reconstruct the shape of flux surfaces and infer the current distribution within the plasma. Equilibrium reconstructions of sawtoothing plasmas that use data from both SXR and external magnetic diagnostics show the central safety factor to be near unity under the assumption that SXR iso-emissivity contours lie on magnetic flux surfaces. The reconstruction results are consistent with those using the external magnetic data and a constraint on the location of q = 1 surfaces determined from the sawtooth inversion surface extracted from SXR brightness profiles. The agreement justifies the use of approximating SXR emission as a flux function in CTH, at least within the core of the plasma, subject to the spatial resolution of the SXR diagnostics. This improved reconstruction of the central current density indicates that the current profile peakedness decreases with increasing external transform and that the internal inductance is not a relevant measure of how peaked the current profile is in hybrid discharges.
Electron heating in the laser and static electric and magnetic fields
Authors: Zhang Yanzeng , Krasheninnikov S. I.
Published: January 2018

A 2D slab approximation of the interactions of electrons with intense linearly polarized laser radiation and static electric and magnetic fields is widely used for both numerical simulations and simplified semi-analytical models. It is shown that in this case, electron dynamics can be conveniently described in the framework of the 3/2 dimensional Hamiltonian approach. The electron acceleration beyond a standard ponderomotive scaling, caused by the synergistic effects of the laser and static electro-magnetic fields, is due to an onset of stochastic electron motion.
A parametrically modulated dual-axis atomic spin gyroscope
Authors: Jiang Liwei , Quan Wei , Li Rujie , Fan Wenfeng , Liu Feng , Qin Jie , Wan Shuangai , Fang Jiancheng
Published: January 2018

We describe a dual-axis atomic spin gyroscope based on an alkali metal-noble gas comagnetometer. Alkali metal vapor is optically pumped, and then the noble gas is hyperpolarized along the z axis. When sensing a transverse rotation, the polarized noble gas will be induced to precess and produce an effective magnetic field in the x – y plane for alkali metals to precess under. Operating in the spin-exchange relaxation-free regime, alkali atoms are modulated by the z axis magnetic field and serve as an integrated in-situ dual-axis magnetometer to detect the gyroscopic precession in the x and y axes simultaneously, using a single probe beam. By using the parametric modulation technique, the low frequency drift is effectively suppressed and a bias instability of less than 0.05 deg/h has been achieved in our dual-axis atomic spin gyroscope.
A photoionization model considering lifetime of high excited states of N2 for PIC-MCC simulations of positive streamers in air
Authors: Jiang Ming , Li Yongdong , Wang Hongguang , Zhong Pengfeng , Liu Chunliang
Published: January 2018

Photoionization plays an important role in the mechanism of positive streamer discharges in air. The photoelectron production rate at high pressures is significantly overestimated in the widely used quantitative photoionization model in nitrogen-oxygen mixtures. A new photoionization model is proposed to surmount this disadvantage approximately by tracking the generation and deactivation of high excited states of N2. Implementation, validation, and discussion of the new photoionization model are presented in this paper. The photoionization coefficient, the fraction of nitrogen ionization events that leads to oxygen photoionization events without quenching, is computed in the new model. It decreases with the increasing pressure when E/p is constant, which agrees with the early experimental results and corrects the overestimation of the photoionization coefficients at high pressures to some extent. Simulations of positive streamers show that the generation and deactivation of high excited states of N2 weaken the discharge of nitrogen and enhance the nonlocal discharge of oxygen with a time delay in the new model. The time delay slows down the positive streamer discharges in our simulations.
Model using curved shore boundaries show shape’s influence on vortex interactions
Authors: Cockbill Louisa
Published: January 2018

Simulations of a simplified interaction between stationary vortices, trapped within a bay’s curved coastline, and incident vortices demonstrate numerous complexities that can result.
A silver fibre prepared by a facile method for solid-phase microextraction of polycyclic aromatic hydrocarbons
Authors: Tian Yu , Zhou Jie , Feng Juanjuan , Wang Xiuqin , Luo Chuannan , Sun Min
Published: January 2018

Environmental contextPolycyclic aromatic hydrocarbons are widespread environmental contaminants of human health concern because of their carcinogenicity. The compounds have low water solubility and thus their measurement in water requires an efficient preconcentration step. We report a simple method for concentrating polycyclic aromatic hydrocarbons from environmental water samples based on their absorption onto a silver fibre. AbstractThe development of highly efficient fibres by a simple preparation method is still a research focus for solid-phase microextraction (SPME). A facile reaction was used to generate a silver coating on silver wire for SPME. The reaction of silver with hydrogen peroxide is very slow, but the formation of [Ag(NH3)2]+ by adding ammonia reduces the electrode potential and increases the reaction rate. The silver fibre was characterised by scanning electron microscopy. Using gas chromatography, the silver fibre was evaluated using polycyclic aromatic hydrocarbons as model analytes. Under optimised extraction conditions, an analysis method was established. A wide linear range (0.06–100 μg L−1) with a good linear coefficient (0.9896–0.9995) and a low detection limit (0.02–0.10 μg L−1) were achieved. The analysis method was used to analyse rainwater and lake water, and achieved a satisfactory recovery (86.3–119 %). The results indicate that the proposed silver fibre has practical applications in environmental analysis.
Metapopulation vicariance in the Pacific genus Coprosma (Rubiaceae) and its Gondwanan relatives
Authors: Heads Michael
Published: January 2018

Coprosma is perhaps the most ubiquitous plant genus in New Zealand. It belongs to the tribe Anthospermeae, which is distinctive in the family Rubiaceae through its small, simple, wind-pollinated flowers and its southern hemisphere distribution. The tribe comprises four main clades found respectively in South Africa, Africa, Australia and the Pacific. The high level of allopatry among the four subtribes is attributed here to their origin by vicariance. The Pacific clade, subtribe Coprosminae, is widespread around the margins of the South Pacific and also occurs on most of the high islands. Distributions of the main clades in the subtribe are mapped here and are shown to be repeated in other groups. The distribution patterns also coincide with features of regional geology. Large-scale volcanism has persisted in the central Pacific region since at least the Jurassic. At that time, the oldest of the Pacific large igneous provinces, the Shatsky Rise, began to be erupted in the region now occupied by French Polynesia. Large-scale volcanism in the central Pacific continued through the Cretaceous and the Cenozoic. The sustained volcanism, along with details of the clade distributions, both suggest that the Coprosminae have persisted in the central Pacific by survival of metapopulations on individually ephemeral islands. It is also likely that vicariance of metapopulations has taken place, mediated by processes such as the subsidence of the Pacific seafloor by thousands of metres, and rifting of active arcs by transform faults. It is sometimes argued that a vicariance origin is unlikely for groups on young, oceanic islands that have never been connected by continuous land, but metapopulation vicariance does not require physical contact between islands.
Biogeographical units matter
Authors: Ferrari Augusto
Published: January 2018

One of the recurrent themes in historical biogeography relates to the units of analysis, their definition and identification. Although areas of endemism are usually accepted as the standard units of study, other units have been suggested, as well as several methods for identifying them. There is no consensus on which units are best suited for the studies; however, the effect of the units and area schemes on analytical results is acknowledged. Here, I review the literature on biogeographic units, their uses and recommendations, highlighting the relevance of the use of more than one area-classification scheme in empirical studies.
Environmental factors related to biogeographical transition zones of areas of endemism of Neotropical mammals
Authors: Noguera-Urbano Elkin Alexi , Ferro Ignacio
Published: January 2018

Biogeographical transition zones are areas of a complex biotic mixture located at the borders between biogeographical units. Climatic, physical and ecological factors should play an important role in allowing coexistence of different biotic elements in the transition zone. Here, we explore the relationship between environmental factors and biogeographical transition zones, defined by Neotropical mammal distributions, by a model selection approach based on the Akaike information criterion and accounting for the spatial structure in the data. We detected three areas of high overlap between mammalian areas of endemism. Two of them corresponded to the well-established regional-level transition zones, namely Mexican (MTZ) and South American (SATZ) transition zones; the third was one located in south-eastern Brazil, approximately between the Paraná and Chacoan dominion that we call The Atlantic Forest integration zone (AF). Only one explicative variable was shared by the three transitions zones (precipitation of the warmest quarter). However, shared variables with great explanatory power indicated two environmental aspects as facilitators for the coexistence of different biotic components in a given geographical area. The first one was the heterogeneity component, either topographic for the SATZ and MTZ or climatic for the AF. The second one was related non-extreme thermal conditions: precipitation of the warmest quarter, interpreted as a thermal buffer, shared by AF and SATZ, and isothermality shared by MTZ and SATZ.
Robust kinase- and age-dependent dopaminergic and norepinephrine neurodegeneration in LRRK2 G2019S transgenic mice
Authors: Xiong Yulan , Neifert Stewart , Karuppagounder Senthilkumar S. , Liu Qinfang , Stankowski Jeannette N. , Lee Byoung Dae , Ko Han Seok , Lee Yunjong , Grima Jonathan C. , Mao Xiaobo , Jiang Haisong , Kang Sung-Ung , Swing Deborah A. , Iacovitti Lorraine , Tessarollo Lino , Dawson Ted M. , Dawson Valina L.
Published: January 2018

Significance

The lack of a robust transgenic mouse model of loss of dopamine (DA) neurons has greatly hindered the study of Parkinson’s disease caused by
LRRK2
mutations. In this manuscript, we report the development of catecholaminergic neuron-specific Tet-inducible conditional transgenic LRRK2 G2019S and LRRK2 G2019S kinase-dead transgenic mice, and show that LRRK2-induced DA and norepinephrine neurodegeneration is kinase-dependent and can occur in a cell-autonomous manner. Moreover, these models reveal that α-synuclein pathology is LRRK2 kinase-dependent and that there are LRRK2 kinase-dependent defects in clathrin-dependent endocytic trafficking that accompany mutant LRRK2-mediated neurodegeneration. These LRRK2 models have the potential to advance our understanding of mutant LRRK2-mediated degeneration of DA neurons.
Anti–PD-1/anti–CTLA-4 efficacy in melanoma brain metastases depends on extracranial disease and augmentation of CD8+T cell trafficking
Authors: Taggart David , Andreou Tereza , Scott Karen J. , Williams Jennifer , Rippaus Nora , Brownlie Rebecca J. , Ilett Elizabeth J. , Salmond Robert J. , Melcher Alan , Lorger Mihaela
Published: January 2018

Inhibition of immune checkpoints programmed death 1 (PD-1) and cytotoxic T lymphocyte-associated protein 4 (CTLA-4) on T cells results in durable antitumor activity in melanoma patients. Despite high frequency of melanoma brain metastases (BrM) and associated poor prognosis, the activity and mechanisms of immune checkpoint inhibitors (ICI) in metastatic tumors that develop within the “immune specialized” brain microenvironment, remain elusive. We established a melanoma tumor transplantation model with intracranial plus extracranial (subcutaneous) tumor, mimicking the clinically observed coexistence of metastases inside and outside the brain. Strikingly, intracranial ICI efficacy was observed only when extracranial tumor was present. Extracranial tumor was also required for ICI-induced increase in CD8+T cells, macrophages, and microglia in brain tumors, and for up-regulation of immune-regulatory genes. Combined PD-1/CTLA-4 blockade had a superior intracranial efficacy over the two monotherapies. Cell depletion studies revealed that NK cells and CD8+T cells were required for intracranial anti–PD-1/anti–CTLA-4 efficacy. Rather than enhancing CD8+T cell activation and expansion within intracranial tumors, PD-1/CTLA-4 blockade dramatically (∼14-fold) increased the trafficking of CD8+T cells to the brain. This was mainly through the peripheral expansion of homing-competent effector CD8+T cells and potentially further enhanced through up-regulation of T cell entry receptors intercellular adhesion molecule 1 and vascular adhesion molecule 1 on tumor vasculature. Our study indicates that extracranial activation/release of CD8+T cells from PD-1/CTLA-4 inhibition and potentiation of their recruitment to the brain are paramount to the intracranial anti–PD-1/anti–CTLA-4 activity, suggesting augmentation of these processes as an immune therapy-enhancing strategy in metastatic brain cancer.
Identification of Wiskott-Aldrich syndrome protein (WASP) binding sites on the branched actin filament nucleator Arp2/3 complex
Authors: Luan Qing , Zelter Alex , MacCoss Michael J. , Davis Trisha N. , Nolen Brad J.
Published: January 2018

Significance

Arp2/3 complex is a macromolecular machine that nucleates branched actin filaments in response to cellular signals. WASP family proteins regulate the nucleation activity of Arp2/3 complex, providing a way for cells to assemble branched actin filament networks with the spatiotemporal precision required to orchestrate cellular processes such as cellular motility and endocytosis. Despite its importance, how WASP activates filament nucleation by Arp2/3 complex is still unknown, largely because it has been uncertain how WASP binds to Arp2/3 complex. Here we use a combination of biophysical, biochemical, and computational methods to map the binding of WASP to the complex. These results have important implications for understanding how cells regulate the assembly of actin filaments.
De novo mutation in
RING1
with epigenetic effects on neurodevelopment
Authors: Pierce Sarah B. , Stewart Mikaela D. , Gulsuner Suleyman , Walsh Tom , Dhall Abhinav , McClellan Jon M. , Klevit Rachel E. , King Mary-Claire
Published: January 2018

Significance

As part of the polycomb repressive complex 1, RING1 contributes to epigenetic regulation of gene expression during development. We identified a de novo mutation in
RING1
in a patient with neurological, skeletal, and immunological abnormalities. The mutation disrupts the ability of RING1 to ubiquitylate histone H2A in nucleosomes, without disrupting its ability to catalyze ubiquitin chain formation. The comparable mutation in
Caenorhabditis elegans
causes defects in neuronal development that are as severe as defects caused by a complete loss of gene function. These results identify
RING1
as critical to neurodevelopment via its involvement in chromatin modification and epigenetic transcriptional regulation.
Spatial aspects of olfactory experience
Authors: Aasen Solveig
Published: January 2018

Several theorists argue that one does not experience something as being at or coming from a distance or direction in olfaction. In contrast to this, I suggest that there can be a variety of spatial aspects of both synchronic and diachronic olfactory experiences, including spatial distance and direction. I emphasise, however, that these are not aspects of every olfactory experience. Thus, I suggest renouncing the widespread assumption there is a uniform account of the nature, including the spatial nature, of what is experienced in olfactory experience.