bluuebunny/crossref_metadata_2025 huggingface dataset:
Hybrid preprocessing aided spatial modulation in multi‐user massive MIMO systems
Authors: Maleki Marjan , Mohamed‐Pour Kamal
Published: May 2018

Massive multiple‐input multiple‐output (MIMO) as a promising technology to achieve high spectral efficiency encounters the problem of high cost and complexity of hardware implementation for digital signal processing. One proposed solution is hybrid analogue–digital processing to reduce the number of radio‐frequency (RF) chains required at massive antenna arrays. In this study, hybrid analogue–digital preprocessing aided spatial modulation is introduced to the downlink of multi‐user massive MIMO systems. Linear zero‐forcing (ZF) and regularised ZF preprocessors which are near‐optimal in massive MIMO systems and a low‐complexity two‐stage preprocessing scheme based on block‐diagonalisation are proposed. These full‐digital schemes are implemented in hybrid RF‐baseband domain through a low‐dimensional processor based on the baseband effective channel and phase controllers at the RF domain. The spatially correlated and sparsely scattered millimetre wave channels are adopted to consider the proposed preprocessing schemes. Under an imperfect channel state information at the transmitter, the robust design of full digital and hybrid analogue‐digital preprocessors is presented using stochastic robust approximation. Furthermore, the hybrid RF‐baseband preprocessors are realised using heavily quantised angles and the preprocessing schemes are investigated from the data rate point of view. The simulation results show desirable performance and close to that of full digital preprocessing is achieved by proper configuration of system.
New approach of automatic generation control based on absolute rotor angle droop control
Authors: Wei Qiang , Guo Moufa , Han Xueshan , Guo Weimin , Yang Ming
Published: May 2018

It is being increasingly recognised that the decentralised secondary frequency regulation (SFR) is more suitable for the expanding power systems. Decentralised SFR can more rapidly restore system frequency and damp generator rotor oscillations, as well as relieve the information‐exchange stress between the control centre and widespread generators. Compared to other previously proposed methods, rotor angle droop (RAD) control is simpler and more straightforward. Similar to primary frequency control, the RAD controllers mainly distribute load variance among generators based on their rated capacity. However, they can rapidly and autonomously restore the system frequency without the intervention of a dispatching centre, which makes it more convenient for distributed generation (such as photovoltaic) to participate in frequency regulation. This study shows that the unbalance value between load forecast and real demand can be calculated through absolute rotor angle deviation. This calculated amount can then be reallocated to achieve more economical results. By calculating the area control error and changing the generation in different areas, the tie‐line power flow (PF) can be controlled similarly. However, the fluctuation on the tie‐line PF can be decreased since generators near the loads bear slightly more burden. This is helpful for tie‐line control in large interconnected power systems.
Centralised busbar differential and wavelet‐based line protection system for multi‐terminal direct current grids, with practical IEC‐61869‐compliant measurements
Authors: Tzelepis Dimitrios , Dyśko Adam , Blair Steven M. , Rousis Anastasios Oulis , Mirsaeidi Sohrab , Booth Campbell , Dong Xinzhou
Published: May 2018

This study presents a method for discriminative detection of direct current (DC) faults on voltage source converter‐powered multi‐terminal high‐voltage direct current transmission systems using two fundamental guiding principles, namely instantaneous current‐differential and travelling waves. The proposed algorithm utilises local voltage and current measurements from all transmission lines connected to a DC busbar, and current measurement from the DC side of the converter. The scheme operates at a sampling frequency of 96 kHz, which conforms with IEC 61869‐9. No long distance communication is involved while measurements and signal exchange within DC substations are enabled by the utilisation of IEC 61850. Performance is assessed firstly through detailed transient simulation, using verified models of modular multi‐level converters, hybrid DC circuit breakers and inductive DC‐line terminations. Furthermore, practical performance and feasibility of the scheme are evaluated through laboratory testing, using the real‐time Opal‐RT hardware prototyping platform. Simulation and experimental results demonstrate that the proposed protection algorithm can effectively, and within a very short period of time (i.e. <1 ms), discriminate between busbar and line faults (internal faults), while remaining stable during external faults. Additionally, it has been demonstrated that IEC 61869‐9 is suitable for enabling fast DC protection schemes incorporating travelling waves.
Short‐term planning model for distribution network restructuring based on heat maps
Authors: Wang Qianggang , Wang Jian , Lei Chao , Zhou Niancheng
Published: May 2018

A short‐term planning model for restructuring distribution network based on heat maps is proposed here. A heat map, as the analytical tool of population density in a geographical map, is used to estimate the maximum air‐conditioning load. Furthermore, the maximum load of each distribution transformer can be obtained. Two criteria for evaluating distribution network planning schemes are suggested. The first criterion is reflecting on the adequacy of the total transforming capacity of substations in a region. The second criterion is reflecting on the qualification of the structure of a 10 kV distribution network. A short‐term planning model of the 10 kV restructuring distribution network is established when the first criterion is satisfied, whereas the second criterion is unsatisfied. The objective function is the minimum restructuring cost, and the constraints are the total and self‐capacity requirements and the connectivity and radial structure of the 10 kV distribution network. Ultimately, a practical 10 kV distribution network is used to verify the effectiveness of the model.
Partial discharge ultrasonic detection based on EULER‐MUSIC algorithm and conformal array sensor
Authors: Pang Xianhai , Wu Han , Li Xiaofeng , Qi Yanxun , Jing Hao , Zhang Jiantao , Xie Qing
Published: May 2018

A conformal array sensor suitable for partial discharge (PD) detection of electrical equipment was designed which displays multiple characteristics including compatibility with the surface of any carrier without affecting the performance of the carrier. Taking a cylindrical conformal array as an example, the simulation model was given and the array flow pattern of the cylindrical conformal array sensor was determined. Based on the Euler transform, the algorithm of multiple signal classification (MUSIC) was improved. An algorithm of array signal direction finding suitable for conformal array sensors was proposed and its performance under different signal‐to‐noise ratios and different array elements was simulated. The improved algorithm and conformal array sensor were used to simulate and test the PD signal. The results show that the algorithm and the conformal array sensor are suitable for PD detection of electrical equipment.
Digital coordination strategy of protection and frequency stability for an islanded microgrid
Authors: Mohamed Emad A. , Magdy Gaber , Shabib Gaber , Elbaset Adel A. , Mitani Yasunori
Published: May 2018

This study presents a digital coordination strategy of load frequency control (LFC) and Over/Under Frequency Relay (OUFR) protection for an isolated microgrid (MG) considering high penetration of renewable energy sources (RESs). In such MGs, the reduction in system inertia due to the replacement of traditional generating units with a large amount of RESs causes undesirable influence to MG frequency stability, leading to weakening of the MG. Furthermore, sudden load change and short circuits caused large frequency fluctuations which threaten the system security. In order to handle these challenges, this study proposes a specific design of the digital OUFR, which will operate for both conditions of over and under frequency in coordination with digital PID controller based on mapping technique in discretization process to protect the MG against high‐frequency variations. To prove the effectiveness of the proposed digital coordination strategy, a small MG was investigated for the simulation considering load change, varying the penetration level of RESs and the system inertia. The results reveal the robustness of the proposed coordination to maintain the MG frequency stability and security. In addition, the superiority of the digital OUFR has been approved in terms of accuracy and speed response during high disturbances.
New protection scheme for power transformer based on superimposed differential current
Authors: Shah Ashesh M. , Bhalja Bhavesh R. , Patel Rajesh M.
Published: May 2018

This study presents a new power transformer protection scheme based on extraction of positive and negative sequence components of superimposed differential currents. Different types of internal faults, magnetising inrush, and over‐excitation conditions have been generated by modelling in service power transformer of power transmission system of India using PSCAD/EMTDC software package. The simulation results clearly indicate the efficacy of the proposed scheme in detecting different types of internal faults like turn‐to‐turn, inter‐winding, line‐to‐ground, line‐to‐line, and line‐to‐line‐to‐ground. Together, the proposed scheme is competent to achieve effective discrimination between various external events (over‐excitation condition and various magnetising inrushes) and internal faults. Moreover, it provides equally promising results during current transformer (CT) saturation condition as well as for different connection and rating of the power transformer. Further, it remains stable during errors in the CT and tap change condition. Additionally, authenticity of the proposed scheme has been evaluated using internal fault and magnetising inrush data recorded in the real field. At the end, comparative assessment of the proposed scheme with the existing and conventional techniques clearly indicate its superiority in terms of better sensitivity for internal faults and higher stability during external events.
Distributed implementation of Kalman object tracker with discrete asynchronous measurements
Authors: Rahmanian Shahabuddin , Bateni Mohammad Hossein , Najafi Majdeddin
Published: May 2018

Typical tracking systems employ tracking filters in order to consecutively estimate the kinematics of a moving object, based on some limited observations of its position and/or velocity which are contaminated by different types of uncertainties. The Kalman filter is the optimal filter for some simple cases. However, in practical scenarios, designing more complicated filters or making modifications to the Kalman filter may be necessary, in order to provide the tracking process with adequate reliability and accuracy. An appropriate design should consider the discipline under which measurements are gathered and the type of disturbances to which the measurement process is exposed. This study investigates the case of quantised, unreliable, asynchronous velocity and position measurements, and proposes an effective design which realises a distributed Kalman filter with two‐ or three‐dimensional state vectors. It is shown via simulations that the proposed design not only smooths the output and combats the effects of quantisation but also keeps on tracking when the measurements are lost for a quite long duration of time.
First‐order ocean surface cross‐section for shipborne HFSWR incorporating a horizontal oscillation motion model
Authors: Yao Guowei , Xie Junhao , Huang Weimin
Published: May 2018

To investigate the characteristic of ocean surface backscatter echo, the first‐order ocean surface cross‐section for shipborne high‐frequency surface wave radar (HFSWR) incorporating a horizontal oscillation motion model is mathematically derived. The horizontal oscillation motion includes yaw, sway and surge. Simulation results show that the horizontal oscillation motion can induce more additional peaks in Doppler spectrum due to combined oscillation motions, and the amplitudes as well as frequency locations of these motion‐induced peaks are determined by the amplitude and frequency of the oscillation motion. Furthermore, the Bragg and motion‐induced peaks are spread due to the forward movement of the ship. These spreading peaks overlap each other as the ship speed increases, which may severely influence moving target detection and ocean remote sensing. However, different characteristics of the first‐order cross‐sections for the true and ambiguous wind directions provide a new idea to measure ocean surface wind direction by shipborne HFSWR with a single receiving antenna.
Virtual energy storage capacity estimation using ANN‐based kWh modelling of refrigerators
Authors: Kumar Kandasamy Nandha , Vijayakumar Krishnasamy , Kalpesh Chaudhari
Published: May 2018

Prolific integration of renewable energy sources (RESs) such as solar photovoltaic systems into the distribution network will result in various issues associated with their intermittent nature. Energy storage is a vital component for overcoming issues associated with the intermittent nature of such RES. Though stationary battery systems are used as energy storage for such applications, smart energy storage (SES) systems are also becoming popular owing to various advantages and advent of smart grid systems. SES can be achieved by aggregating electric vehicles (EVs) or by using demand response management for loads with large time constants. Aggregated residential refrigerators are potential candidates for creating SES which has virtual storage capacity, unlike EVs. In this study, residential refrigerators are modelled analogously to energy capacity and self‐discharge of electro‐chemical batteries using the artificial neural network based kWh modelling. The model is further extended to estimate the virtual energy storage (VES) capacity with aggregated residential refrigerators; particularly in high‐rise residential buildings. Simulation results are presented for scenarios covering the complete range of thermal capacity of typical refrigerators applicable in Singapore's climatic condition. Furthermore, a brief description of the possible applications for the estimated VES, pertaining to smart grid architecture and cyber‐attack is also presented.
Using Internet of Things and biosensors technology for health applications
Authors: Hamidi Hodjat , Fazeli Kimia
Published: May 2018

The growing trend of ageing has created many challenges. One of these challenges is the rehabilitation of individuals who take time, resources and manpower. The motivation for this study is to propose an ontology‐based automatic design methodology for use in intelligent rehabilitation systems in the Internet of things (IoTs). For interconnection, all health system resources in a network use IoT technology. In order to provide fast and effective rehabilitation for different patients, IoT is combined with ontology. The experimental results obtained from rehabilitation of the lower limbs show that the IoT‐based rehabilitation system works properly and an ontology‐based approach can help create an effective rehabilitation strategy, configure and quickly deploy all available resources with the requirements given. In this study, three types of biosensors have been selected. These biosensors are used for blood, saliva and breathing tests. The expansion of the growth and maturity of technology based on the Fisher‐Pry model is based on patent and bibliometrics analysis. The analysis of intellectual property rights according to their number indicates that blood vital sensors reached their turning point in 2009, but the vital sensors of saliva and respiration will reach their turning point and maturity with a delay of 8–14 years.
Stampacchia–Caldéron–Zygmund theory for linear elliptic equations with discontinuous coefficients and singular drift
Authors: Boccardo Lucio
Published: May 2018

In this paper, the existence and properties of solutions of the boundary value problem (1.4) are studied. No regularity assumptions on the coefficients of the matrixM(x) are used (in particular we do not require that the principal part is −Δ), no assumptions on the size of ||E||LNare needed.
Multilinear Stockwell transforms
Authors: Catană Viorel
Published: May 2018

The main aim of this paper is to introduce multilinear versions of the Stockwell transforms (also named S-transforms) by using the fact that S-transforms can be written as convolution products. Further on we extend the multilinear S-transforms from the Schwartz class of rapidly decreasing functions to the space of tempered distributions. In the sequel we give a relation between multilinear S-transforms and multilinear pseudo-differential operators.

We also state and prove some boundedness results regarding multilinear S-transforms on the Lebegue’s spaces Lp(Rn) and also on the Hörmander’s spaces Bp,k(Rn), where p ≥ 1 and k is a temperate weight function. In the end, a weak uncertainty principle for multilinear S-transforms and for its adjoint is also given.
Net reproduction functions for nonlinear structured population models
Authors: Farkas József Z.
Published: May 2018

The goal of this note is to present a general approach to define the net reproduction function for a large class of nonlinear physiologically structured population models. In particular, we are going to show that this can be achieved in a natural way by reformulating a nonlinear problem as a family of linear ones; each of the linear problems describing the evolution of the population in a different, but constant environment. The reformulation of a nonlinear population model as a family of linear ones is a new approach, and provides an elegant way to study qualitative questions, for example the existence of positive steady states. To define the net reproduction number for any fixed (constant) environment, i.e. for the linear models, we use a fairly recent spectral theoretic result, which characterizes the connection between the spectral bound of an unbounded operator and the spectral radius of a corresponding bounded operator. For nonlinear models, varying the environment naturally leads to a net reproduction function.
The Effect of Fulminant Hepatic Failure on Protein C Antigen and Activity
Authors: Langley P G , Williams Roger
Published: May 2018

In eighteen patients with fulminant hepatic failure (FHF), ingrade III or IV coma, both protein C antigen and activity weresignificantly decreased (0.35 ± 0.03 u/ml and 0.35 ± 0.03 u/ml respectively). There was a significant correlation between pro-tein C antigen and activity (r = 0.61, p <0.01). Protein C antigenlevels were inversely correlated with prothrombin time (r =−0.57, p <0.05) as were protein C activity levels (r = —0.57, p<0.05). There was also significant correlations between fibrinogen and protein C antigen (r = 0.69, p <0.01) and protein Cactivity (r = 0.61, p <0.01). These results demonstrate that thenaturally occurring inhibitor of coagulation, protein C, is presentat low levels in FHF and this is probably due to the lack ofsynthesis of the protein in the damaged liver. The low levels ofprotein C may make these patients more susceptible to thedisseminated intravascular coagulation which is known to occur inFHF and this in turn will lead to a further reduction in protein Clevels.
Daytime Fluctuations in Blood of Tissue-Type Plasminogen Activator (t-PA) and Its Fast-Acting Inhibitor (PAI-1)
Authors: Kluft C , Jie A F H , Rijken D C , Verheijen J H
Published: May 2018

Circadian fluctuation in blood fibrinolytic activity was studiedin 10 volunteers in the day-time period at 09.00, 12.00 and15.0 h. Activity of tissue-type plasminogen activator (t-PA) wasfound to increase from 09.00 to 15.00 h in accordance with knownresults with global assays of blood activity.
Generation of magneto-immersed electron beams
Authors: Pikin A. , Raparia D.
Published: May 2018

There are many applications of electron beams in accelerator facilities: for electron coolers, electron lenses, and electron beam ion sources (EBIS) to mention a few. Most of these applications require magnetic compression of the electron beam to reduce the beam radius with the goal of either matching the circulating ion beam (electron lenses and electron coolers) or increasing the ionization capability for the production of highly charged ions (EBIS). The magnetic compression of the electron beam comes at a cost of increasing share of the transverse component of energy and therefore increased angles of the electron trajectories to the longitudinal axis. Considering the effect of the magnetic mirror, it is highly desirable to produce a laminar electron beam in the electron gun. The analysis of electron guns with different configurations is given in this paper with emphasis on generating laminar electron beams.
In situ high-pressure measurement of crystal solubility by using neutron diffraction
Authors: Chen Ji , Hu Qiwei , Fang Leiming , He Duanwei , Chen Xiping , Xie Lei , Chen Bo , Li Xin , Ni Xiaolin , Fan Cong , Liang Akun
Published: May 2018

Crystal solubility is one of the most important thermo-physical properties and plays a key role in industrial applications, fundamental science, and geoscientific research. However, high-pressure in situ measurements of crystal solubility remain very challenging. Here, we present a method involving high-pressure neutron diffraction for making high-precision in situ measurements of crystal solubility as a function of pressure over a wide range of pressures. For these experiments, we designed a piston-cylinder cell with a large chamber volume for high-pressure neutron diffraction. The solution pressures are continuously monitored in situ based on the equation of state of the sample crystal. The solubility at a high pressure can be obtained by applying a Rietveld quantitative multiphase analysis. To evaluate the proposed method, we measured the high-pressure solubility of NaCl in water up to 610 MPa. At a low pressure, the results are consistent with the previous results measured ex situ. At a higher pressure, more reliable data could be provided by using an in situ high-pressure neutron diffraction method.
Influence of 20 MeV electron irradiation on the optical properties and phase composition of SiOx thin films
Authors: Hristova-Vasileva Temenuga , Petrik Peter , Nesheva Diana , Fogarassy Zsolt , Lábár János , Kaschieva Sonia , Dmitriev Sergei N. , Antonova Krassimira
Published: May 2018

Homogeneous films from SiO1.3 (250 nm thick) were deposited on crystalline Si substrates by thermal evaporation of silicon monoxide. A part of the films was further annealed at 700 °C to grow amorphous Si (a-Si) nanoclusters in an oxide matrix, thus producing composite a-Si-SiO1.8 films. Homogeneous as well as composite films were irradiated by 20-MeV electrons at fluences of 7.2 × 1014 and 1.44 × 1015 el/cm2. The film thicknesses and optical constants were explored by spectroscopic ellipsometry. The development of the phase composition of the films caused by the electron-beam irradiation was studied by transmission electron microscopy. The ellipsometric and electron microscopy results have shown that the SiOx films are optically homogeneous and the electron irradiation with a fluence of 7.2 × 1014 el/cm2 has led to small changes in the optical constants and the formation of very small a-Si nanoclusters. The irradiation of the a-Si-SiOx composite films caused a decrease in the effective refractive index and, at the same time, an increase in the refractive index of the oxide matrix. Irradiation induced increase in the optical band gap and decrease in the absorption coefficient of the thermally grown amorphous Si nanoclusters have also been observed. The obtained results are discussed in terms of the formation of small amorphous silicon nanoclusters in the homogeneous layers and electron irradiation induced reduction in the nanocluster size in the composite films. The conclusion for the nanoparticle size reduction is supported by infrared transmittance results.
Molecular transport through membranes: Accurate permeability coefficients from multidimensional potentials of mean force and local diffusion constants
Authors: Sun Rui , Han Yining , Swanson Jessica M. J. , Tan Jeffrey S. , Rose John P. , Voth Gregory A.
Published: May 2018

Estimating the permeability coefficient of small molecules through lipid bilayer membranes plays an important role in the development of effective drug candidates. In silico simulations can produce acceptable relative permeability coefficients for a series of small molecules; however, the absolute permeability coefficients from simulations are usually off by orders of magnitude. In addition to differences between the lipid bilayers used in vitro and in silico, the poor convergence of permeation free energy profiles and over-simplified diffusion models have contributed to these discrepancies. In this paper, we present a multidimensional inhomogeneous solubility-diffusion model to study the permeability of a small molecule drug (trimethoprim) passing through a POPC (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine) lipid bilayer. Our approach improves the permeation model in three ways: First, the free energy profile (potential of mean force, PMF) is two-dimensional in two key coordinates rather than simply one-dimensional along the direction normal to the bilayer. Second, the 2-D PMF calculation has improved convergence due to application of the recently developed transition-tempered metadynamics with randomly initialized replicas, while third, the local diffusivity coefficient was calculated along the direction of the minimum free energy path on the two-dimensional PMF. The permeability is then calculated as a line integral along the minimum free energy path of the PMF. With this approach, we report a considerably more accurate permeability coefficient (only 2–5 times larger than the experimental value). We also compare our approach with the common practice of computing permeability coefficients based only on the translation of the center of mass of the drug molecule. Our paper concludes with a discussion of approaches for minimizing the computational cost for the purpose of more rapidly screening a large number of drug candidate molecules.
Non-local electron transport through normal and topological ladder-like atomic systems
Authors: Kurzyna Marcin , Kwapiński Tomasz
Published: May 2018

We propose a locally protected ladder-like atomic system (nanoconductor) on a substrate that is insensitive to external perturbations. The system corresponds to coupled atomic chains fabricated on different surfaces. Electron transport properties of such conductors are studied theoretically using the model tight-binding Su-Schriffer-Hegger (SSH) Hamiltonian and Green's function formalism. We have found that the conductance of the system is almost insensitive to single adatoms and oscillates as a function of the side chain length with very large periods. Non-local character of the electron transport was observed also for topological SSH chains where nontrivial end states survive in the presence of disturbances as well as for different substrates. We have found that the careful inspection of the density of states or charge waves can provide the information about the atom energy levels and hopping amplitudes. Moreover, the ladder-like geometry allows one to distinguish between normal and topological zero-energy states. It is important that topological chains do not reveal Friedel oscillations which are observed in non-topological chains.
Nonequilibrium thermodynamics and boundary conditions for reaction and transport in heterogeneous media
Authors: Gaspard Pierre , Kapral Raymond
Published: May 2018

Nonequilibrium interfacial thermodynamics is formulated in the presence of surface reactions for the study of diffusiophoresis in isothermal systems. As a consequence of microreversibility and Onsager-Casimir reciprocal relations, diffusiophoresis, i.e., the coupling of the tangential components of the pressure tensor to the concentration gradients of solute species, has a reciprocal effect where the interfacial currents of solutes are coupled to the slip velocity. The presence of surface reactions is shown to modify the diffusiophoretic and reciprocal effects at the fluid-solid interface. The thin-layer approximation is used to describe the solution flowing near a reactive solid interface. Analytic formulas describing the diffusiophoretic and reciprocal effects are deduced in the thin-layer approximation and tested numerically for the Poiseuille flow of a solution between catalytic planar surfaces.
Amplitude mediated chimera states with active and inactive oscillators
Authors: Mukherjee Rupak , Sen Abhijit
Published: May 2018

The emergence and nature of amplitude mediated chimera states, spatio-temporal patterns of co-existing coherent and incoherent regions, are investigated for a globally coupled system of active and inactive Ginzburg-Landau oscillators. The existence domain of such states is found to shrink and shift in parametric space with the increase in the fraction of inactive oscillators. The role of inactive oscillators is found to be twofold—they get activated to form a separate region of coherent oscillations and, in addition, decrease the common collective frequency of the coherent regions by their presence. The dynamical origin of these effects is delineated through a bifurcation analysis of a reduced model system that is based on a mean field approximation. Our results may have practical implications for the robustness of such states in biological or physical systems where age related deterioration in the functionality of components can occur.
Thermally activated delayed fluorescence organic dots for two-photon fluorescence lifetime imaging
Authors: He Tingchao , Ren Can , Li Zhuohua , Xiao Shuyu , Li Junzi , Lin Xiaodong , Ye Chuanxiang , Zhang Junmin , Guo Lihong , Hu Wenbo , Chen Rui
Published: May 2018

Autofluorescence is a major challenge in complex tissue imaging when molecules present in the biological tissue compete with the fluorophore. This issue may be resolved by designing organic molecules with long fluorescence lifetimes. The present work reports the two-photon absorption (TPA) properties of a thermally activated delayed fluorescence (TADF) molecule with carbazole as the electron donor and dicyanobenzene as the electron acceptor (i.e., 4CzIPN). The results indicate that 4CzIPN exhibits a moderate TPA cross-section (∼9 × 10−50 cm4 s photon−1), high fluorescence quantum yield, and a long fluorescence lifetime (∼1.47 μs). 4CzIPN was compactly encapsulated into an amphiphilic copolymer via nanoprecipitation to achieve water-soluble organic dots. Interestingly, 4CzIPN organic dots have been utilized in applications involving two-photon fluorescence lifetime imaging (FLIM). Our work aptly demonstrates that TADF molecules are promising candidates of nonlinear optical probes for developing next-generation multiphoton FLIM applications.
Epigenetic switch from repressive to permissive chromatin in response to cold stress
Authors: Park Junghoon , Lim Chae Jin , Shen Mingzhe , Park Hee Jin , Cha Joon-Yung , Iniesto Elisa , Rubio Vicente , Mengiste Tesfaye , Zhu Jian-Kang , Bressan Ray A. , Lee Sang Yeol , Lee Byeong-ha , Jin Jing Bo , Pardo Jose M. , Kim Woe-Yeon , Yun Dae-Jin
Published: May 2018

Significance

Phenotypic adaptations of plants in response to changes in climate are well known to be mediated by molecular mechanisms, including activation or suppression of transcription factors that control target gene expression. However, the chromatin changes that are essential for the binding of transcription factors are much less understood. Gene derepression at the chromatin level is considered to be the starting point for gene transcription. We report a mechanism of gene derepression through which HOS15 promotes the degradation of histone deacetylase HD2C in a cold-dependent manner that correlates with increased levels of acetylated histones on
COR
gene chromatin. Moreover, HOS15 directly promotes
COR
gene transcription by association of CBF transcription factors with the “open” state of the target
COR
chromatin.
Direct evidence of a large Northern European Roman period martial event and postbattle corpse manipulation
Authors: Holst Mads Kähler , Heinemeier Jan , Hertz Ejvind , Jensen Peter , Løvschal Mette , Mollerup Lene , Odgaard Bent Vad , Olsen Jesper , Søe Niels Emil , Kristiansen Søren Munch
Published: May 2018

Significance

Here we present direct archaeological evidence in the form of human remains of a large-scale battle in Northern Europe in the first century AD, in the wake of the northern expansion of the Roman Empire. The deposited population is estimated to 380 individuals. The relative absence of traces of healed sharp force trauma suggests that they had relatively little previous battle experience. Evidence of the systematic treatment of the human corpses, including stripping of bodies, disarticulation of bones, crushing of crania, and arrangement of body parts, points to a new form of postbattle activities, with implications for the interpretation of contemporary battlefields and later ritual traditions with regard to depositions of the spoils of war.
Structural basis of O-GlcNAc recognition by mammalian 14-3-3 proteins
Authors: Toleman Clifford A. , Schumacher Maria A. , Yu Seok-Ho , Zeng Wenjie , Cox Nathan J. , Smith Timothy J. , Soderblom Erik J. , Wands Amberlyn M. , Kohler Jennifer J. , Boyce Michael
Published: May 2018

Significance

O-GlcNAc is an abundant, reversible posttranslational modification (PTM) of nuclear and cytoplasmic proteins in animals and plants. O-GlcNAc regulates a wide range of biological processes, and aberrant O-GlcNAcylation is implicated in numerous human diseases. However, key aspects of O-GlcNAc signaling remain poorly understood. For example, it is not known whether “reader” proteins exist to recognize and bind to O-GlcNAc, as is true for many other PTMs. We used a biochemical method to identify candidate human O-GlcNAc reader proteins, and then characterized them at the biochemical and biophysical levels. Our results address a significant gap in the cell signaling field by revealing the biochemical and structural basis for the recognition of O-GlcNAc by conserved human proteins.
Structure of an EIIC sugar transporter trapped in an inward-facing conformation
Authors: Ren Zhenning , Lee Jumin , Moosa Mahdi Muhammad , Nian Yin , Hu Liya , Xu Zhichun , McCoy Jason G. , Ferreon Allan Chris M. , Im Wonpil , Zhou Ming
Published: May 2018

Significance

The phosphoenolpyruvate-dependent phosphotransferase system (PTS) is a multiprotein system unique to bacteria. The PTS transports sugars into bacteria and then phosphorylates the sugars. Phosphorylation prevents sugars from escaping the cell and primes them for metabolic consumption. As a major component of the PTS, Enzyme IIC (EIIC) transports sugar across the membrane and assists the phosphorylation process, but the molecular mechanism of EIIC-mediated sugar transport is unclear. Results from this study allow visualization of conformational changes during sugar transport and establish the mechanism of transport at the atomic level. The knowledge will facilitate development of inhibitors against EIIC and provide a foundation for understanding the phosphorylation process.
Acoustic evolution of old Italian violins from Amati to Stradivari
Authors: Tai Hwan-Ching , Shen Yen-Ping , Lin Jer-Horng , Chung Dai-Ting
Published: May 2018

Significance

Amati and Stradivari violins are highly appreciated by musicians and collectors, but the objective understanding of their acoustic qualities is still lacking. By applying speech analysis techniques, we found early Italian violins to emulate the vocal tract resonances of male singers, comparable to basses or baritones. Stradivari pushed these resonance peaks higher to resemble the shorter vocal tract lengths of tenors or altos. Stradivari violins also exhibit vowel qualities that correspond to lower tongue height and backness. These properties may explain the characteristic brilliance of Stradivari violins. The ideal for violin tone in the Baroque era was to imitate the human voice, and we found that Cremonese violins are capable of producing the formant features of human singers.
Prediction of the behaviour of copper alloy components under complex loadings by electro-thermomechanical coupled simulations
Authors: Weber M. , Helm D.
Published: May 2018

Electronic devices must be served with electric power for different reasons. A robust and reliable electric connectivity is often realised by electric connectors. For its leading properties, precipitation hardened copper alloys are widely used for designing connectors with high level mechanical or conductance properties. However, copper alloys show a characteristic stress relaxation under mechanical or thermal loads. Finite element analysis is a standard method to design and optimise components with respect to reliability and performance. Hence, a material model considering the characteristic of the mechanical properties and allowing for the simulation of time and temperature dependent elasto-viscoplastic material behavior was developed at the Fraunhofer IWM. The parameters of the model were determined using tensile and relaxation test data of a C19010 alloy. The material model is applied to electro-thermomechanical coupled finite element simulations of connectors with different load histories. The goal of the simulations is the analysis of the impact of stress relaxation on the mechanical properties of systems over time. From the numerical results with the new model it is shown, how stress relaxation influences the connector clamping forces or contact pressure, respectively, in dependence with time or temperature. The simulation results documents that stress relaxation has to be taken into account in finite element simulations during the designing process of electrical devices.

This paper is part of a Thematic Issue on Copper and its Alloys.
Part-time work and gender inequality in Europe: a comparative analysis of satisfaction with work–life balance
Authors: Beham Barbara , Drobnič Sonja , Präg Patrick , Baierl Andreas , Eckner Janin
Published: May 2018

Part-time work is an increasingly common strategy for handling work and family – but is it an effective strategy everywhere and for everyone? To answer this question, we examine satisfaction with work–life balance (SWLB) of workers in 22 European countries. Our results show that part-time workers have higher SWLB than full-time workers; the more so, the fewer hours they put in. Yet, we find an important gender difference: women in marginal part-time work are more satisfied than men in a similar situation, and conversely men in full-time work have higher SWLB than women working full-time. Further, the societal context plays an important role: substantial part-time work is more conducive to SWLB in more gender-egalitarian countries than in countries with low gender equality. Hence, a supportive gender climate and institutional support may entice workers to reduce working hours moderately, which results in markedly increased levels of SWLB.
Processing ‘Gender-neutral’ Pronouns: A Self-paced Reading Study of Learners of English
Authors: Speyer Lydia Gabriela , Schleef Erik
Published: May 2018

This article explores the online processing of singular he and she and singular they by learners of English to discover whether singular they presents a processing problem for non-native speakers (NNSs). It also examines the extent to which such issues may vary as a function of L2 proficiency at B2, C1, and C2 levels. A self-paced reading study was conducted with 51 students at an Austrian university. Results were compared with a similar study based on data collected from native speakers. We found advanced NNSs matching those of native speakers in almost all respects, and we present some evidence for developmental progression in how he, she, and they are processed. Pronoun-specific details are built up over time, and we suggest their relative strength depends on the robustness of the input. We provide self-reported production data to support this argument. This study paints a very optimistic picture of the acquisition of singular they at B2 and higher proficiency levels, as it can be acquired even under circumstances of later familiarization.
The Composite Spreader Flap
Authors: Bitik Ozan , Kamburoğlu Haldun Onuralp , Uzun Hakan
Published: May 2018

Background

The effect of a spreader flap on the keystone area and the upper bony vault depends on the structural strength and cephalic extent of upper lateral cartilages, both of which can be significantly variable among individuals.

Objectives

The authors present a novel cephalically extended osseocartilaginous composite spreader flap technique that was designed to overcome the limitations of a conventional spreader flap on the keystone area upper bony vault, in patients with cephalically short and structurally weak upper lateral cartilages and thin nasal bones.

Methods

This study was a retrospective review of the recorded perioperative information to investigate the frequency of the use of the composite spreader flap technique and perioperative parameters that relate to postoperative dorsal deformities. One-hundred-seventy-six consecutive primary open approach rhinoplasty cases performed by the first author (O.B.) between November 2015 and February 2017 were included in the study. Patient data were obtained from rhinoplasty data sheets, standardized photographs, and postoperative physical examinations.

Results

Of the 176 cases who underwent primary open approach rhinoplasty whose data were reviewed for the purpose of this study, 38 (32 females, 6 males) had dorsal reconstruction with the use of a composite spreader flap. Seventeen patients had a deviated nose with an asymmetric bony pyramid. In 8 patients, the composite spreader flap was used unilaterally. No patients in the composite spreader flap group had a postoperative dorsal deformity or required surgical revision.

Conclusions

Composite flap preparation extends the reliability and the reach of the spreader flap technique beyond its previous borders.

Level of Evidence: 4
Identification of serum glycoprotein ligands for the immunomodulatory receptor blood dendritic cell antigen 2
Authors: Kim Jong-won , Budzak James , Liu Yu , Jégouzo Sabine A F , Drickamer Kurt , Taylor Maureen E
Published: May 2018

Blood dendritic cell antigen 2 (BDCA-2) is a C-type lectin found on the surface of plasmacytoid dendritic cells. It functions as a glycan-binding receptor that downregulates the production of type I interferons and thus plays a role in oligosaccharide-mediated immunomodulation. The carbohydrate recognition domain in BDCA-2 binds selectively to galactose-terminated bi-antennary glycans. Because the plasmacytoid dendritic cells function in a plasma environment rich in glycoproteins, experiments have been undertaken to identify endogenous ligands for blood dendritic cell antigen 2. A combination of blotting, affinity chromatography and proteomic analysis reveals that serum glycoprotein ligands for BDCA-2 include IgG, IgA and IgM. Compared to binding of IgG, which was previously described, IgA and IgM bind with higher affinity. The association constants for the different subclasses of immunoglobulins are below and roughly proportional to the serum concentrations of these glycoprotein ligands. Binding to the other main serum glycoprotein ligand, α2-macroglobulin, is independent of whether this protease inhibitor is activated. Binding to all of these glycoprotein ligands is mediated predominantly by bi-antennary glycans in which each branch bears a terminal galactose residue. The different affinities of the glycoprotein ligands reflect the different numbers of these galactose-terminated glycans and their degree of exposure on the native glycoproteins. The results suggest that normal serum levels of immunoglobulins could downmodulate interferon stimulation of further antibody production.
Insights into Electroreceptor Development and Evolution from Molecular Comparisons with Hair Cells
Authors: Baker Clare V H , Modrell Melinda S
Published: May 2018

The vertebrate lateral line system comprises a mechanosensory division, with neuromasts containing hair cells that detect local water movement (“distant touch”); and an electrosensory division, with electrosensory organs that detect the weak, low-frequency electric fields surrounding other animals in water (primarily used for hunting). The entire lateral line system was lost in the amniote lineage with the transition to fully terrestrial life; the electrosensory division was lost independently in several lineages, including the ancestors of frogs and of teleost fishes. (Electroreception with different characteristics subsequently evolved independently within two teleost lineages.) Recent gene expression studies in a non-teleost actinopterygian fish suggest that electroreceptor ribbon synapses employ the same transmission mechanisms as hair cell ribbon synapses, and show that developing electrosensory organs express transcription factors essential for hair cell development, including Atoh1 and Pou4f3. Previous hypotheses for electroreceptor evolution suggest either that electroreceptors and hair cells evolved independently in the vertebrate ancestor from a common ciliated secondary cell, or that electroreceptors evolved from hair cells. The close developmental and putative physiological similarities implied by the gene expression data support the latter hypothesis, i.e., that electroreceptors evolved in the vertebrate ancestor as a “sister cell-type” to lateral line hair cells.
Finite-region boundedness and stabilization for 2D continuous-discrete systems in Roesser model
Authors: Hua Dingli , Wang Weiqun , Yu Weiren , Wang Yixiang
Published: May 2018

This paper investigates the finite-region boundedness (FRB) and stabilization problems for two-dimensional continuous-discrete linear Roesser models subject to two kinds of disturbances. For two-dimensional continuous-discrete system, we first put forward the concepts of finite-region stability and FRB. Then, by establishing special recursive formulas, sufficient conditions of FRB for two-dimensional continuous-discrete systems with two kinds of disturbances are formulated. Furthermore, we analyze the finite-region stabilization issues for the corresponding two-dimensional continuous-discrete systems and give generic sufficient conditions and sufficient conditions that can be verified by linear matrix inequalities for designing the state feedback controllers which ensure the closed-loop systems FRB. Finally, viable experimental results are demonstrated by illustrative examples.
Semi-infinite Plücker Relations and Weyl Modules
Authors: Feigin Evgeny , Makedonskyi Ievgen
Published: May 2018

The goal of this paper is two-fold. First, we write down the semi-infinite Plücker relations, describing the Drinfeld–Plücker embedding of the (formal version of) semi-infinite flag varieties in type A. Second, we study the homogeneous coordinate ring, that is, the quotient by the ideal generated by the semi-infinite Plücker relations. We establish the isomorphism with the algebra of dual global Weyl modules and derive a new character formula.
Connectedness and Lyubeznik Numbers
Authors: Núñez-Betancourt Luis , Spiroff Sandra , Witt Emily E
Published: May 2018

We investigate the relationship between connectedness properties of spectra and the Lyubeznik numbers, numerical invariants defined via local cohomology. We prove that for complete equidimensional local rings, the Lyubeznik numbers characterize when connectedness dimension equals 1. More generally, these invariants determine a bound on connectedness dimension. Additionally, our methods imply that the Lyubeznik number $\lambda _{1,2}(A)$ of the local ring $A$ at the vertex of the affine cone over a projective variety is independent of the choice of its embedding into projective space.