bluuebunny/crossref_metadata_2025 huggingface dataset:
Nonstationary Teleconnection Between the Pacific Ocean and Arctic Sea Ice
Authors: Bonan D. B. , Blanchard‐Wrigglesworth E.
Published: January 2020

Over the last 40 years observations show a teleconnection between summertime Pacific Ocean sea surface temperatures and September Arctic sea ice extent. However, the short satellite observation record has made it difficult to further examine this relationship. Here, we use 30 fully coupled general circulation models (GCMs) participating in Phase 5 of the Coupled Model Intercomparison Project to assess the ability of GCMs to simulate this teleconnection and analyze its stationarity over longer timescales. GCMs can temporarily simulate the teleconnection in continuous 40‐year segments but not over longer, centennial timescales. Each GCM exhibits considerable teleconnection variability on multidecadal timescales. Further analysis shows that the teleconnection depends on an equally nonstationary atmospheric bridge from the subequatorial Pacific Ocean to the upper Arctic troposphere. These findings indicate that the modulation of Arctic sea ice loss by subequatorial Pacific Ocean variability is not fixed in time, undermining the assumption of teleconnection stationarity as defined by the satellite record.
La Niña's Diminishing Fingerprint on the Central Indian Summer Monsoon
Authors: Samanta Dhrubajyoti , Rajagopalan Balaji , Karnauskas Kristopher B. , Zhang Lei , Goodkin Nathalie F.
Published: January 2020

La Niña years tend to provide increased Indian summer monsoon (ISM) rainfall. However, observations show 6–8% reduction in ISM rainfall during post‐1980 La Niñas relative to pre‐1980. Using a suite of atmospheric general circulation model experiments, we replicate this observed phenomenon and attribute it to a combination of weakening La Niña events themselves plus strongly warming tropical Indian Ocean. We demonstrate that half of the ISM rainfall reduction during post‐1980 La Niñas can be attributed to changes in the spatial pattern and intensity of La Niña within the tropical Pacific Ocean. Warmer eastern‐equatorial Pacific Ocean temperatures during post‐1980 La Niñas weaken the Walker circulation, resulting in large‐scale anomalous subsidence over the Indian subcontinent, thereby inhibiting the deep convection that drives ISM rainfall. Further, we demonstrate the declining central ISM rainfall during La Niña years with increasing tropical Indian Ocean warming, which has several serious concerns for regional water resources and stability.
Climate Adaptation as a Control Problem: Review and Perspectives on Dynamic Water Resources Planning Under Uncertainty
Authors: Herman Jonathan D. , Quinn Julianne D. , Steinschneider Scott , Giuliani Matteo , Fletcher Sarah
Published: January 2020

Climate change introduces substantial uncertainty to water resources planning and raises the key question: when, or under what conditions, should adaptation occur? A number of recent studies aim to identify policies mapping future observations to actions—in other words, framing climate adaptation as an optimal control problem. This paper uses the control paradigm to review and classify recent dynamic planning studies according to their approaches to uncertainty characterization, policy structure, and solution methods. We propose a set of research gaps and opportunities in this area centered on the challenge of characterizing uncertainty, which prevents the unambiguous application of control methods to this problem. These include exogenous uncertainty in forcing, model structure, and parameters propagated through a chain of climate and hydrologic models; endogenous uncertainty in human‐environmental system dynamics across multiple scales; and sampling uncertainty due to the finite length of historical observations and future projections. Recognizing these challenges, several opportunities exist to improve the use of control methods for climate adaptation, namely, how problem context and understanding of climate processes might assist with uncertainty quantification and experimental design, out‐of‐sample validation and robustness of optimized adaptation policies, and monitoring and data assimilation, including trend detection, Bayesian inference, and indicator variable selection. We conclude with a summary of recommendations for dynamic water resources planning under climate change through the lens of optimal control.
Patch‐Based Multiscale Algorithm for Flow and Reactive Transport in Fracture‐Microcrack Systems in Shales
Authors: Wang Ziyan , Battiato Ilenia
Published: January 2020

A major challenge in modeling reactive transport in shales is the multiscale nature of the fractured rock system. Shales may contain a few main fractures and thousands of microcracks whose length and aperture are orders of magnitude smaller than the former. This renders fully resolved simulations too expensive, while traditional upscaling methods cannot accurately capture fracture clogging dynamics due to precipitation. We develop a fully coupled patch‐based multiscale algorithm to address this issue: We solve reactive transport only in a few selected microcracks, while evaluating the others by interpolation and ensuring top‐down bottom‐up coupling between the main fracture and the microcracks. Specifically, we consider a fracture system with an array of hundreds of microcracks connected to a main fracture. The patch‐based multiscale algorithm is validated against fully resolved pore‐scale simulations and a steady‐state analytical solution. We find the reaction rate can have a great impact on the concentration profiles after breakthrough, even if the profiles before breakthrough are similar. Also, the breakthrough curves exhibit three dynamic regimes when microcrack aperture alterations are accounted for.
Deep-Channel uses deep neural networks to detect single-molecule events from patch-clamp data
Authors: Celik Numan , O’Brien Fiona , Brennan Sean , Rainbow Richard D. , Dart Caroline , Zheng Yalin , Coenen Frans , Barrett-Jolley Richard
Published: January 2020

Single-molecule research techniques such as patch-clamp electrophysiology deliver unique biological insight by capturing the movement of individual proteins in real time, unobscured by whole-cell ensemble averaging. The critical first step in analysis is event detection, so called “idealisation”, where noisy raw data are turned into discrete records of protein movement. To date there have been practical limitations in patch-clamp data idealisation; high quality idealisation is typically laborious and becomes infeasible and subjective with complex biological data containing many distinct native single-ion channel proteins gating simultaneously. Here, we show a deep learning model based on convolutional neural networks and long short-term memory architecture can automatically idealise complex single molecule activity more accurately and faster than traditional methods. There are no parameters to set; baseline, channel amplitude or numbers of channels for example. We believe this approach could revolutionise the unsupervised automatic detection of single-molecule transition events in the future.
A novel immobilization fluorescence capillary analysis method and its applications
Authors: Li Yong-Sheng , Li Qiao-Jing , Gao Xiu-Feng
Published: January 2020

Fluorescence capillary analysis (FCA) realizes trace-level analysis of micro-volume samples; it is easy to operate, extremely low in analytical cost and can significantly lessen environmental pollution from analytical chemistry waste.
Emulsification solidified floating organic drop microextraction assisted by ultrasound for the determination of nickel, cobalt and copper in oyster and fish samples
Authors: de S. Dias Fabio , de S. R. Neto Salvador C. , de N. Pires Laís , Lemos Valfredo A.
Published: January 2020

In the present work, solidified floating organic drop microextraction assisted by ultrasound is proposed as the preconcentration system for the determination of trace amounts of nickel, cobalt and copper by FAAS.
Optimization of a heterogeneous Pd–Cu/zeolite Y Wacker catalyst for ethylene oxidation
Authors: Imbao Jerick , van Bokhoven Jeroen A. , Nachtegaal Maarten
Published: January 2020

A heterogeneous catalyst based on palladium- and copper-exchanged zeolite Y is optimized for stable Wacker oxidation.
Synthesis of aryl-substituted 2-methoxyphenol derivatives from maltol-derived oxidopyrylium cycloadducts through an acid-mediated ring contraction cascade
Authors: Bejcek Lauren P. , Murelli Ryan P.
Published: January 2020

Maltol-derived oxidopyrylium cycloadducts undergo two different types of acid-mediated rearrangements to form 2-methoxyphenol derivatives.
A novel water-soluble quinoline–indole derivative as a three-photon fluorescent probe for identifying nucleolus RNA and mitochondrial DNA
Authors: Elhussin Imad Elddin Haj , Zhang Sijing , Liu Jiejie , Li Dandan , Zhang Qiong , Li Shengli , Tian Xiaohe , Wu Jieying , Tian Yupeng
Published: January 2020

We present the design and synthesis of water-soluble quinoline–indole-based derivatives (IM-1, IM-2, and IM-3) with three-photon absorption activity.
Active centre and reactivity descriptor of a green single component imidazole catalyst for acetylene hydrochlorination
Authors: Zhao Chaoyue , Qiao Xianliang , Yi Zenghuimin , Guan Qingxin , Li Wei
Published: January 2020

The mechanisms and reactivities of imidazole-catalyzed acetylene hydrochlorination have been investigated by combined computational and experimental studies.
NiO nanocomposites/rGO as a heterogeneous catalyst for imidazole scaffolds with applications in inhibiting the DNA binding activity
Authors: Kumar Gyanendra , Mogha Navin Kumar , Kumar Manish , Subodh  , Masram Dhanraj T.
Published: January 2020

NiO nanocomposites immobilized over surface-functionalized rGO sheets for catalytic synthesis of trisubstituted imidazoles with applications in inhibiting DNA binding activity.
Harnessing the active site triad: merging hemilability, proton responsivity, and ligand-based redox-activity
Authors: Baumgardner Douglas F. , Parks Wyatt E. , Gilbertson John D.
Published: January 2020

Metalloenzymes catalyze important reactions by managing the proton and electron flux at the active site. In synthetic systems; hemilability, proton responsivity, and ligand-based redox-activity can be utilized as a bridge to harness this reactivity.
Effect of metal ion substitution on the catalytic activity of a pentanuclear metal complex
Authors: Akai Takuya , Kondo Mio , Lee Sze Koon , Izu Hitoshi , Enomoto Takafumi , Okamura Masaya , Saga Yutaka , Masaoka Shigeyuki
Published: January 2020

A pentanuclear cobalt complex that consists of five cobalt ions and six bpp− ligands (Co5, Hbpp = 3,5-bis(2-pyridyl)pyrazole) was newly developed. The obtained complex can catalyze CO2 reduction under electrochemical and photochemical conditions.
Shedding light on the aqueous synthesis of silicon nanoparticles by reduction of silanes with citrates
Authors: Ddungu John L. Z. , Silvestrini Simone , Tassoni Alessandra , De Cola Luisa
Published: January 2020

The synthesis in water of silicon nanoparticles yields to an emissive carbon/silica composite.
Freeze–thaw repetition as an auxiliary method to promote efficient separation of hemicellulose from poplar
Authors: Zhu Huixia , Ma Qianli , Sheng Jie , Yang Rendang
Published: January 2020

The application of freeze–thaw repetition as a pretreatment method in hydrothermal treatment and green upgradation of poplar biomass has been investigated.
Extraction of phenylurea herbicides from rice and environmental water utilizing MIL-100(Fe)-functionalized magnetic adsorbents
Authors: Zhang Hongyuan , Jieying Wang , Zhengji Liang , Fan Rong , Chen Qian , Shan Xueru , Jiang Chunzhu , Sun Guoying
Published: January 2020

In this paper, a novel method is reported for the extraction and enrichment of phenylurea herbicides (PUHs) from rice and environmental water samples using MIL-100(Fe)-functionalized magnetic nanoparticles as adsorbents.
Tuned structure and DNA binding properties of metal complexes based on a new 4-acylpyrazolone derivative
Authors: Xi Wei , Song Fu-Qiang , Xia Xue-Li , Song Xue-Qin
Published: January 2020

The structure and DNA binding performance of three transition metal compounds based on a new pyrazolone ligand were tuned effectively by changing both metal cations and anions.
Magnetic vortex nucleation and annihilation in bi-stable ultra-small ferromagnetic particles
Authors: Martínez-Pérez M. J. , Müller B. , Lin J. , Rodriguez L. A. , Snoeck E. , Kleiner R. , Sesé J. , Koelle D.
Published: January 2020

We nucleate and manipulate magnetic vortices in ultrasmall magnetic nanoparticles and provide the full picture of their thermal and temporal stability.
Penetration of the blood–brain barrier and the anti-tumour effect of a novel PLGA-lysoGM1/DOX micelle drug delivery system
Authors: Yin Ying , Wang Jun , Yang Meng , Du Ruolin , Pontrelli Giuseppe , McGinty Sean , Wang Guixue , Yin Tieying , Wang Yazhou
Published: January 2020

a) Diagram depicting the preparation of drug delivery system of PLGA-lysoGM1/DOX micelles. b) Schematic illustration of micelles elicited antitumor. c) Micelles cross BBB via micropinocytosis and autophagy/lysosomal pathways.
A layered Ge2Sb2Te5phase change material
Authors: Zhang Bo , Cicmancova Veronika , Kupcik Jaroslav , Slang Stanislav , Rodriguez Pereira Jhonatan , Svoboda Roman , Kutalek Petr , Wagner Tomas
Published: January 2020

In this study, a universal Ge2Sb2Te5phase change material was sputtered to obtain a layered structure.
A single-molecule study reveals novel rod-like structures formed by a thrombin aptamer repeat sequence
Authors: Liu Jianyu , Feng Wei , Zhang Wenke
Published: January 2020

Single-molecule magnetic tweezers and AFM imaging studies reveal novel rod-like structures formed by a thrombin aptamer repeat sequence.
Single-atom transition metals supported on black phosphorene for electrochemical nitrogen reduction
Authors: Liu Kang , Fu Junwei , Zhu Li , Zhang Xiaodong , Li Hongmei , Liu Hui , Hu Junhua , Liu Min
Published: January 2020

Electrochemical nitrogen reduction reaction (NRR) is a promising route to produce ammonia under mild conditions. Single-atom W supported on BP was screened as a promising electrocatalyst with high catalytic activity, stability, and selectively for NRR.
An ultraflexible polyurethane yarn-based wearable strain sensor with a polydimethylsiloxane infiltrated multilayer sheath for smart textiles
Authors: Li Xiaoting , Koh Keng Huat , Farhan Musthafa , Lai King Wai Chiu
Published: January 2020

This paper proposes an ultraflexible polyurethane yarn-based strain sensor. It demonstrates superior performance and enormous potential in monitoring full-range human motions and manipulate a hand robot to move, catch, and grasp some objects.
N-Doped-carbon/cobalt-nanoparticle/N-doped-carbon multi-layer sandwich nanohybrids derived from cobalt MOFs having 3D molecular structures as bifunctional electrocatalysts for on-chip solid-state Zn–air batteries
Authors: Zhao Juanjuan , Hu Haibo , Wu Mingzai
Published: January 2020

Based on well-designed N-doped-carbon/cobalt-nanoparticle/N-doped-carbon nanohybrids of unique thousand-layer-cake porous structure with excellent bifunctional electrocatalytic activity, on-chip all-solid-state flexible rechargeable Zn–air batteries are developed.
A bifunctional nanoporous Ni–Co–Se electrocatalyst with a superaerophobic surface for water and hydrazine oxidation
Authors: Feng Zhongbao , Wang Enping , Huang Shuai , Liu Jiming
Published: January 2020

The superaerophobic nature induced by the porous structure of Ni0.6Co0.4Se results in its superior electrocatalytic performance towards both HzOR and OER.
Probing the helical integrity of multivicinal all-syn-fluoro alkanes
Authors: Al-Maharik Nawaf , Cordes David B. , Slawin Alexandra M. Z. , Bühl Michael , O'Hagan David
Published: January 2020

The synthesis and conformation of an all-syn 2,3,4.7.8,9 hexafluoro alkane is explored by X-ray, NMR and DFT.
Natural phenolic compound–iron complexes: sustainable solar absorbers for wood-based solar steam generation devices
Authors: Gao He , Yang Mingming , Dang Ben , Luo Xiongfei , Liu Shouxin , Li Shujun , Chen Zhijun , Li Jian
Published: January 2020

Natural phenolic compound–iron complexes were used as sustainable solar absorbers for wood-based solar steam generation devices.
Collective and contractile filament motions in the myosin motility assay
Authors: Jung Wonyeong , Fillenwarth Luke A. , Matsuda Atsushi , Li Jing , Inoue Yasuhiro , Kim Taeyoon
Published: January 2020

In this computational study of the myosin motility assay, we demonstrated that volume-exclusion effects lead to distinct collective behaviors of actin filaments, whereas actin cross-linking proteins induce contractile behaviors of actin filaments.
N-Heterocyclic carbene-ended polymers as surface ligands of plasmonic metal nanoparticles
Authors: Thanneeru Srinivas , Ayers Kaitlynn M. , Anuganti Murali , Zhang Lei , Kumar Challa V. , Ung Gaël , He Jie
Published: January 2020

A facile methodology to prepare N-heterocyclic carbene (NHC)-terminated polymers as surface ligands to functionalize gold nanoparticles (AuNPs) is reported.
Molecular design featuring carbazole-decorated 15H-diindolo[2,3-b:1′,2′,3′-lm]carbazole for improved efficiency and lifetime of thermally activated delayed fluorescence emitters
Authors: Konidena Rajendra Kumar , Lee Kyung Hyung , Lee Jun Yeob
Published: January 2020

In this report, we developed a novel electron donor named 12-(9-phenyl-9H-carbazol-3-yl)-15H-diindolo[2,3-b:1′,2′,3′-lm]carbazole (CzDICz) for efficient TADF emitters with long operational lifetime.
MgB2for MRI applications: dual sintering induced performance variations inin situand IMD processed MgB2conductors
Authors: Patel Dipak , Matsumoto Akiyoshi , Kumakura Hiroaki , Maeda Minoru , Kim Su-Hun , Al Hossain Md Shahriar , Choi Seyong , Kim Jung Ho
Published: January 2020

Dual sintering induced performance variations in MgB2superconductors are studied in detail in relation to MRI applications.
Double peak emission in lead halide perovskites by self-absorption
Authors: Schötz Konstantin , Askar Abdelrahman M. , Peng Wei , Seeberger Dominik , Gujar Tanaji P. , Thelakkat Mukundan , Köhler Anna , Huettner Sven , Bakr Osman M. , Shankar Karthik , Panzer Fabian
Published: January 2020

We demonstrate that the often observed double peak emission in lead halide perovskites is caused by an extensive self-absorption effect.
Point‐selection and multi‐level‐point‐feature fusion‐based 3D point cloud classification
Authors: Zhang Qieshi , Cheng Jun , Wang Shengwen , Xu Chengjun , Gao Xiangyang
Published: January 2020

Recent years, the research on object classification based on three‐dimensional (3D) point cloud pays more attention to extract the features from point sets directly. PointNet++ is the latest network structure for 3D classification which has achieved acceptable results. Although it has achieved acceptable results, there are still two problems: (i) The farthest point sampling (FPS) algorithm in PointNet++ ignores the fact that the feature of each point contributes differently to the classification and segmentation tasks. Therefore, FPS cannot guarantee that the selected point sets can correctly represent the main features of the object. (ii) The multi‐scale grouping and multi‐resolution grouping in PointNet++ do not consider the features between different levels of the same point. In order to solve these problems, the authors propose the point‐selection structure which can calculate the importance of each point's feature. In addition, multi‐level‐point‐feature fusion module is proposed to extract the features of the point at all levels and fuse them as a new feature of that point. In this Letter, they make some experiments on ModelNet40 and ScanNet datasets, which achieves better results compared to the state‐of‐the‐art methods.
Polarimetric SAR image despeckling using bandelet transform based on additive–multiplicative speckle model
Authors: Roy T. , Sethunadh R. , Ameer P.M.
Published: January 2020

Efficient speckle filtering algorithms are required for the effective use of polarimetric synthetic aperture radar (SAR) technology in remote sensing and surveillance applications. Nevertheless many techniques have been proposed over the past two decades to decrease the speckle noise in polarimetric SAR images, they are all based on the multiplicative speckle noise model. In order to fully utilise the advantages of polarimetry of these images, an additive–multiplicative noise model is explored. Coupled with this, bandelet based Bayesian thresholding is used to tap the advantages of transform domain filtering. Here the elements of the covariance matrix are processed differently for diagonal and off‐diagonal elements to achieve maximum benefits. The proposed filtering scheme is evaluated using airborne and spaceborne polarimetric images and compared against state‐of‐the‐art techniques. Results indicate that the proposed method reduces the speckle content while retaining the geometrical features in these images.
Methodological approach for workspace boundary determination in joint space using support vector machine
Authors: Seol W. , Kim K.‐S. , Kim S.
Published: January 2020

For most industrial robots using position control, self‐collision is a headache. Without well‐defined constraints at a joint level, self‐collision can lead to damage to a robot or even injury to the operator. In this study, a new methodological approach is proposed that is different from the traditional methods of using sensors or analysing kinematics. The proposed method uses a support vector machine to construct a joint boundary map based on the robot's movement in the workspace. To verify its feasibility and performance, simulations are conducted. The proposed method is believed to help reduce the cost and computational burden. It is expected to be utilised even in applications where the existing methods are difficult to use.
Investigation of radiation recovery effect on sensing fibre in BOTDR
Authors: Li Mi , Zhang Yizhuo , Chen Zhang , Guo You , Zhang Xinyu , Zhang Xuping
Published: January 2020

The radiation recovery effect on sensing fibre in Brillouin optical time‐domain reflectometer (BOTDR) has been experimentally investigated. In the experiment, three kinds of commercial single‐mode G.652.D fibres: Yangtze Optical Fibre and Cable, Corning and Fujikura have been used as sensing fibre in BOTDR system. After 200 Gy dose gamma‐ray radiation absorbed by sensing fibre, the performance of BOTDR at different time intervals has been tested. Moreover, by analysing Brillouin gain spectra along with fibre sample, the recovery in radiation‐induced attenuation, the variation of Brillouin frequency shift and the variation of stress coefficient are characterised. The results will be helpful for the error correction in the simulation experiment and are a reliable basis for the introduction of BOTDR into the space station.
Robust second‐order finite‐time formation control of heterogeneous multi‐agent systems on directed communication graphs
Authors: Mei Feng , Wang He , Yao Yiyang , Fu Junjie , Yuan Xiang , Yu Wenwu
Published: January 2020

This study concentrates on the finite‐time (FT) formation control problem for a class of heterogeneous second‐order (SO) multi‐agent systems (MASs), where disturbance may exist in the dynamics of each agent and the communication graph is directed. First of all, a basic FT formation control protocol is proposed for the nominal SO MAS and the finite convergence time is calculated. To solve the FT formation control for a class of heterogeneous SO MASs without using global information, an adaptive FT formation control is then proposed. Finally, two numerical examples are presented to validate the theoretical results.
Robust tracking and model following of uncertain non‐linear systems with time‐varying delays and dead‐zone inputs
Authors: Wu Hansheng
Published: January 2020

The problem of robust tracking and model following is considered for a class of uncertain non‐linear systems with any time‐varying delays and completely unknown dead‐zone input non‐linearity. Here, time‐varying delays are assumed to be any continuous and bounded non‐negative functions, and any information on their derivatives need not known. In the study, the system uncertainties assumed to be any continuous and bounded non‐linear functions, and their non‐linear upper bounds do not need also to be known. Based on Wu inequality, a novel design method is presented by which some simple and direct robust tracking control schemes can be easily constructed. It is shown that the tracking error between the output of an actual dynamical system and the dynamical signals of the given reference model can be guaranteed to be uniformly exponentially bounded. A numerical example is also given to describe the design procedure of the presented method, and the simulations of this numerical example are implemented to demonstrate the validity of the theoretical results.
Design of a robust current controller for grid‐connected photovoltaic systems based on cascaded multilevel inverter
Authors: Felicio de Sousa Silva Andre , Pires Pimentel Sergio , Marra Enes Goncalves , Pinheiro de Alvarenga Bernardo
Published: January 2020

This work proposes a design method for robust state feedback grid current controller applied to single‐phase grid‐connected photovoltaic (PV) systems. The proposed method achieved high system reliability even dealing with grid distorted voltages and other power quality issues. The robustness of the controller was verified in the face of parametric uncertainties at the first‐order output filter, and also a satisfactory disturbance rejection performance was achieved. The proposed design is based on linear matrix inequalities associated with constraints involving optimisation and a pole placement analysis on the continuous‐time domain. A discrete‐time analysis is also presented in order to indicate the simplicity of its implementation by a microcontroller or similar devices. Based on the presented results and in order to validate the proposed controller, its robust performance was compared with two linear and well‐known control methods: a classical PI controller, in terms of robustness; and a robust resonant controller, regarding the power quality at the connection point with the grid‐utility. Although the conclusions were listed regarding a low voltage PV grid‐interactive multilevel power converter, the proposed control design (and its concepts) can be applied to a great variety of renewable energy resources systems.
Investigation on distribution of electro‐thermal coupled field and improved design of ±1100 kV converter valve‐side bushing
Authors: Liu Xuandong , Chen Ming , Liang Chengjun , Tang Hao , Zhang Qiaogen
Published: January 2020

Compared to bushings with lower voltage levels, the ±1100 kV converter valve‐side bushing has thicker radial insulation and longer axial insulation resulting in a more uneven temperature distribution and more severe electric field distortion, especially under high‐ambient‐temperature and high‐current conditions. Improving the distribution of the electro‐thermal coupled field of the bushing is critical for the safe operation of converter transformers. This study discusses the distribution of electro‐thermal coupled field of a typical bushing and proposes a new method to evaluate the conductivity of multiple capacitor layers under inhomogeneous axial temperatures. The effects of four bushing designs are investigated as per the adjustment of the capacitor screen structure, the replacement of the current‐carrying structure, and the modification of resin‐impregnated paper material. The results show that merely adjusting the capacitor screens is not feasible due to size limitations. By decreasing heat accumulation, adopting a single‐tube structure and increasing the thermal conductivity of resin‐impregnated paper material can reduce electric field distortion to a certain extent. Unlike the other three methods, hierarchically controlling the material resistance effectively balances the internal and external electric fields. Simulation results demonstrate the feasibility of these methods to improve the distribution of the electro‐thermal coupled field in the bushing.
Accumulative effect of partial discharges at impulse voltage wave tail
Authors: Florkowski Marek
Published: January 2020

This study describes a technique for evaluating partial discharges at fast impulse voltages. Fast transient voltages are increasingly present in power equipment and industrial environments due to the ubiquitous application of power electronics switching devices. Special attention should be paid to the dangers caused by the accumulative effect of repetitive impulse voltages on electrical insulation. This study describes a method of analysing partial discharges occurring during impulse voltage stimuli. A repetitive train of pulses is applied to a dielectric specimen and the accumulated PD pattern is obtained. This study focuses on the reverse discharges which occur during the tail part of the impulse voltage waveform acquired in time‐resolved mode. Investigations of the partial discharges in the wave tail can potentially lead to greater degradation of the insulation due to the formation of longer, repetitive sequence occurring along the decaying impulse voltage tail. Experiments were performed which investigated the influence of rise time, fall time and peak voltage on discharge pattern reshaping, intensity and time to inception on the tail. In the future, such an approach might be further developed for diagnostic applications and for extended factory tests.
Some aspects of medium voltage switchgear designing with aid of numerical analysis
Authors: Krajewski Wojciech , Krasuski Krzysztof , Błażejczyk Tomasz
Published: January 2020

Numerical analysis has been applied to estimate the electric and electromagnetic fields in a medium voltage compact switchgear. The electric field evaluation enables to establish proper dimensions of the switchgear inner devices, e.g. bushing insulators. The electromagnetic field estimation with proposed (by the authors) models of main circuit connections leads to more accurate identification of Joule heating sources. These heat sources can be applied in the further thermo‐ventilation analysis.
Effects of voltage forms, pressure, and adsorbent on the SF6 decomposition characteristics under corona discharge
Authors: Zhong Lipeng , Liu Kai , Ji Shengchang , Wang Feng , Sun Qiuqin , Chen She , Liu Jie
Published: January 2020

An experimental and testing platform was established to comparative study the decomposition characteristic of SF6 under different voltage waveform (negative direct current (DC) voltage, positive DC voltage, and alternating voltage), and investigate the influence of pressure and adsorbent. Content variation of typical products under different conditions and the influence mechanism were observed and analysed in detail. The results indicate that SF6 decomposition characteristics are closely related to a voltage waveform, pressure, and adsorbent. Concentrations of by‐products under AC voltage are higher than those under DC voltage and SF6 decomposes more easily under positive voltage than negative voltage, which can be explained by different discharge energy and distribution characteristic of space charges. The values of typical products show an obvious downward trend with pressure due to falling discharge energy, volume of active region and dissociation rate of SF6. Concentrations of typical products including SOF2, SO2F2, and SO2 decrease dramatically after adding adsorbents because of physical absorption and chemisorption.
Contribution to the study of fission products release from nuclear fuels in severe accident conditions: effect of the pO2 on Cs, Mo and Ba speciation
Authors: Le Gall Claire , Audubert Fabienne , Léchelle Jacques , Pontillon Yves , Hazemann Jean-Louis
Published: January 2020

The objective of this work is to experimentally investigate the effect of the oxygen potential on the fuel and FP chemical behaviour in conditions representative of a severe accident. More specifically, the speciation of Cs, Mo and Ba is investigated. These three highly reactive FP are among the most abundant elements produced through 235U and 239Pu thermal fission and may have a significant impact on human health and environmental contamination in case of a light water reactor severe accident. This work has set out to contribute to the following three fields: providing experimental data on Pressurized Water Reactor (PWR) MOX fuel behaviour submitted to severe accident conditions and related FP speciation; going further in the understanding of FP speciation mechanisms at different stages of a severe accident; developing a method to study volatile FP behaviour, involving the investigation of SIMFuel samples manufactured at low temperature through SPS. In this paper, a focus is made on the impact of the oxygen potential towards the interaction between irradiated MOX fuels and the cladding, the interaction between Mo and Ba under oxidizing conditions and the assessment of the oxygen potential during sintering.
An efficient method for estimating the damping ratio of a vibration isolation system
Authors: Yu Qiang , Xu Dengfeng , Zhu Yu , Guan Gaofeng
Published: January 2020

As the damping ratio determines the response of a vibration isolation system at resonance, it is very necessary to estimate the damping ratio quickly and economically for an evaluation of the effectiveness to adjust the damping in practical engineering applications. An efficient method named the “ζ-Tr” method with the characteristics of simple operation and a high accuracy is introduced to estimate the damping ratio in this paper. According to the transmissibility curve, the specific mathematical relationship in which the value of the resonance peak corresponds to the value of the damping ratio is analysed theoretically. In this case, the recognition of the resonance peak can be used to directly estimate the damping ratio without an approximation or simplification. The “ζ-Tr” method is faster, more accurate and less costly than other estimation methods. Finally, the correctness of the “ζ-Tr” method is verified by a simulation and an experiment.
Adjuvant Radiotherapy and/or Chemotherapy for Endometrial Cancer, Status as at 2019
Authors: Emons Günter , Tempfer Clemens , Battista Marco Johannes , Mustea Alexander , Vordermark Dirk ,   for the Uterus Commission of the AGO
Published: January 2020

The role of adjuvant radiotherapy and/or chemotherapy in the primary treatment of endometrial cancer with a high risk of recurrence has still not been conclusively determined. The results of 3 large randomized controlled studies on different aspects of this issue have been published in full in recent months, and the relevant results are analyzed here.
Circulating and Disseminated Tumor Cells in Breast Carcinoma
Authors: Banys-Paluchowski Malgorzata , Fehm Tanja , Janni Wolfgang , Solomayer Erich-Franz , Hartkopf Andreas
Published: January 2020

Hematogenous dissemination of single tumor cells from the primary tumor is a common phenomenon in most solid malignancies. In breast cancer, presence of circulating tumor cells (CTCs) in the peripheral blood and disseminated tumor cells (DTCs) in bone marrow predicts poor clinical outcome, both in early and metastatic setting. Beyond that, persistence of CTCs/DTCs is associated with shorter relapse-free interval as well. Numerous studies have shown that these cells differ from tumor cells in the primary tumor with regard to hormone and HER2 receptor status and it has been hypothesized that some of them might be in fact cancer stem cells. Recently, the first positive study on CTC-based therapy interventions has been presented at the San Antonio Breast Cancer Symposium 2018, demonstrating that detection of CTCs may guide treatment decisions in metastatic HR-positive HER2-negative disease. In this review, we present the current state of evidence of tumor cell dissemination and discuss the implications for future trials.
Fortgeschrittenes Magenkarzinom
Authors: Schmale Ine
Published: January 2020

Bei Patienten mit fortgeschrittenem Magenkarzinom bzw. Karzinomen des gastroösophagealen Übergangs (GE/GEJC) zeigte eine Erstlinientherapie mit einer anti-PD-1-gerichteten Immuntherapie plus Chemotherapie keinen Überlebensvorteil versus Chemotherapie, obwohl die Kombination Immun- plus Chemotherapie bei Kopf-Hals-Krebs und NSCLC erfolgreich waren. Für die Therapie des fortgeschrittenen Magenkarzinoms kristallisiert sich jetzt möglicherweise ein Patientenkollektiv heraus, das von einer Immuntherapie in der ersten Therapielinie profitieren könnte. Dass auch in der Ära der zielgerichteten und immunonkologischen Therapien die Optimierung der Chemotherapie weiterhin zur Überlebensverlängerung beitragen kann, zeigen aber auch die Ergebnisse der asiatischen Studie SOLAR.
ER-positives Mammakarzinom
Authors: Krome Susanne
Published: January 2020

Bei Frauen mit Östrogenrezeptor-positiven Mammakarzinomen besteht über Jahrzehnte ein Metastasierungsrisiko. Die endokrine Therapie mit Tamoxifen reduziert die Rezidivrate und die Mortalität. Die Effektivität ist unbestritten, aber der langfristige Nutzen in Abhängigkeit vom Hormonrezeptorstatus war bisher unbekannt. Die Sekundäranalyse der STO-3-Studie nach 25 Jahren ergab Unterschiede für Luminal-A- und Luminal-B-Tumoren.
Deutscher Schmerzkongress 2019
Authors: Kretzschmar Alexander
Published: January 2020

Auf dem Deutschen Schmerzkongress 2019 wurde die neue S2k-Leitlinie zur Diagnose und nicht-interventionellen Therapie neuropathischer Schmerzen vorgestellt. Ebenfalls in Mannheim gezeigt wurden die Ergebnisse einer großen Online-Befragung der Deutschen Gesellschaft für Schmerzmedizin (DGS) und der Deutschen Schmerzliga (DSL) unter mehreren tausend Betroffenen. „Die Auswertung deckt schmerzmedizinische Versorgungslücken auf, die alle Beteiligten zum Umdenken motivieren sollten“, mahnte Priv.-Doz. Dr. Michael Überall die Kongressteilnehmer.
The Use of Intravenous Prostaglandins in Extremity Ischemia
Authors: Samuel Vimalin , Selvaraj Dheepak , Kota Albert Abhinay , Stephen Edwin
Published: January 2020

Introduction Prostaglandins are potent vasoactive agents with other properties of vasodilatation, fibrinolysis and inhibition of platelet aggregation. Prostaglandin E1 (PGE1) has been used in the treatment of peripheral vascular diseases (PVD), mainly in patients with nonreconstructable PVD and also as an adjunct when there is residual ischemia after revascularization. Our experience in using PGE1 at a tertiary care center in South India is presented here along with a review of literature.

Materials and Methods Patients presenting to us with nonreconstructable critical limb ischemia underwent prostaglandin infusion after meeting selection criteria.

Results Of the 142 patients enrolled into the study, 48 completed the study. There was a shift in the profile of patients from critical limb ischemia to claudicants or minor tissue loss.

Discussion In the absence of options to treat patients with nonreconstructable critical limb ischemia, prostaglandin infusion offers a viable option for treatment.

Conclusion PGE1 infusion is an option for patients with nonreconstructable critical limb ischemia.
Ceftolozane/Tazobactam in Neonates and Young Infants: The Challenges of Collecting Pharmacokinetics and Safety Data in This Vulnerable Patient Population
Authors: Ang Jocelyn Y. , Arrieta Antonio , Bradley John S. , Zhang Zufei , Yu Brian , Rizk Matthew L. , Johnson Matthew G. , Rhee Elizabeth G.
Published: January 2020

Objective New treatments are needed for multidrug-resistant (MDR) gram-negative infections in neonates. Ceftolozane/tazobactam is a β-lactam/β-lactamase inhibitor combination that has broad-spectrum activity against most common gram-negative bacteria, including MDR strains. We evaluated pharmacokinetics (PK) and safety of ceftolozane/tazobactam in term and premature neonates and young infants.

Study Design This is a subgroup analysis of a phase 1, noncomparative, open-label, multicenter study that characterized the PK, safety, and tolerability of a single intravenous (IV) dose of ceftolozane/tazobactam in pediatric patients with proven/suspected gram-negative infection or receiving perioperative prophylaxis.

Results Seven patients were enrolled in Group A (birth [7 days postnatal] to < 3 months, > 32 weeks gestation) and six patients were enrolled in Group B (birth [7 days postnatal] to < 3 months, ≤ 32 weeks gestation). PK profiles in neonates and young infants were generally comparable to those of older children receiving a single IV dose of ceftolozane/tazobactam. No serious adverse events (AEs), treatment-related AEs, severe AEs, or clinically significant laboratory abnormalities were reported.

Conclusion Among term and premature neonates and young infants, PK was comparable to older children and ceftolozane/tazobactam was generally well tolerated. An adaptable and flexible study design is necessary for enrollment in neonatal PK trials.
Characterizing the complexity of time series networks of dynamical systems: A simplicial approach
Authors: Chutani Malayaja , Rao Nithyanand , Nirmal Thyagu N. , Gupte Neelima
Published: January 2020

We analyze the time series obtained from different dynamical regimes of evolving maps and flows by constructing their equivalent time series networks, using the visibility algorithm. The regimes analyzed include periodic, chaotic, and hyperchaotic regimes, as well as intermittent regimes and regimes at the edge of chaos. We use the methods of algebraic topology, in particular, simplicial complexes, to define simplicial characterizers, which can analyze the simplicial structure of the networks at both the global and local levels. The simplicial characterizers bring out the hierarchical levels of complexity at various topological levels. These hierarchical levels of complexity find the skeleton of the local dynamics embedded in the network, which influence the global dynamical properties of the system and also permit the identification of dominant motifs. We also analyze the same networks using conventional network characterizers such as average path lengths and clustering coefficients. We see that the simplicial characterizers are capable of distinguishing between different dynamical regimes and can pick up subtle differences in dynamical behavior, whereas the usual characterizers provide a coarser characterization. However, the two taken in conjunction can provide information about the dynamical behavior of the time series, as well as the correlations in the evolving system. Our methods can, therefore, provide powerful tools for the analysis of dynamical systems.
Swing equation in power systems: Approximate analytical solution and bifurcation curve estimate
Authors: Qiu Qi , Ma Rui , Kurths Jurgen , Zhan Meng
Published: January 2020

The swing equation plays a central role in the model and analysis of power system dynamics, including small-signal stability and transient stability. As it has the same form as that in a variety of different disciplines, such as the forced pendulum in mechanics, the classical mechanistic description of superconducting Josephson junctions in physics, and the classical second-order phase-locking loop in electronics, it has aroused general interest in science and engineering. In this paper, its approximate solution of the limit cycle is obtained by means of the incremental harmonic balance (IHB) method. It is found that the trouble of a more distorted limit cycle when the parameters are closer to the homoclinic bifurcation curve can be easily solved by incorporating higher order harmonics in the IHB method. In this way, we can predict the homoclinic bifurcation curve perfectly. In addition, the method is extended to study a generalized swing equation including excitation voltage dynamics.
Simultaneously estimating the thermal conductivity and thermal diffusivity of a poorly conducting solid material using single surface measurements
Authors: Malheiros Fernando Costa , Gomes do Nascimento Jefferson , Fernandes Ana Paula , Guimarães Gilmar
Published: January 2020

This paper presents a new experimental method that simultaneously obtains the thermal conductivity and thermal diffusivity of a solid. This technique uses a new surface probe with a resistance heater, two thermocouples, and a heat flux sensor. In this method, part of the top of the sample is heated, and two regions on this surface (one heated and the other not) are used to estimate the thermal properties of the material. This technique minimizes two distinct functions that are defined from surface temperature measurements, using, however, different thermal concepts. The first uses the gain ratio between two surface temperatures to determine the thermal diffusivity. The second uses the well-known square quadratic error function calculated with the same experimental and theoretical values of the temperatures of the surface to estimate the thermal conductivity.
Emergent dynamics of the Lohe matrix ensemble on a network under time-delayed interactions
Authors: Ha Seung-Yeal , Kim Doheon , Kim Dohyun , Park Hansol , Shim Woojoo
Published: January 2020

We study emergent dynamics of the Lohe matrix model on the unitary group in the presence of several external factors. First, we consider how the static network structure can affect the emergent dynamics for the identical ensemble. To be more precise, we present a sufficient framework leading to the completely aggregated state and improve asymptotic dynamics on the all-to-all network case. Second, we investigate the uniform time-delay structure effect on the emergent dynamics of the Lohe matrix model and show that complete aggregation can occur when the size of the time-delay is sufficiently small. Finally, we study the interplay between the network structure and time-delayed interactions in the asymptotic dynamics of the Lohe matrix model. In this case, we cannot expect complete synchronous behavior. Instead, we show that the system exhibits weak aggregation, namely, practical aggregation, when the coupling strength is sufficiently large.
Pulsed power technology based on semiconductor opening switches: A review
Authors: Rukin S. N.
Published: January 2020

This paper presents a systematized review of the research on the production of nanosecond high-power pulses using solid-state generators based on an inductive energy store and a semiconductor opening switch that have been performed in the past 25 years. This research has been underway since 1992–1993 when the nanosecond cutoff of ultrahigh-density currents in semiconductor diodes was discovered and named the SOS (Semiconductor Opening Switch) effect. The discovery of the SOS effect provided a breakthrough in the development of semiconductor generators, as their most important characteristics, such as pulse power and output voltage, were increased tens and hundreds of times compared with previously known semiconductor generators. In particular, in the nanosecond semiconductor technology, megavolt voltages combined with gigawatt peak powers have been achieved. This review considers the main physical processes that determine the mechanism of operation of a SOS based on the SOS effect. The principle of operation, design, and characteristics of SOS diodes and SOS generators is described, and prospects for their further development are discussed. Examples are given of using SOS generators in various pulsed power applications such as electron accelerators, X-ray pulse devices, high-power microwave electronics, pumping of gas lasers, and ignition of electrical discharges.