bluuebunny/crossref_metadata_2025 huggingface dataset:
Enhanced-contrast optical readout in ultrafast broadband Raman quantum memories
Authors: Zheltikov A. M.
Published: September 2018

The signal-to-noise contrast of the optical readout in broadband Raman quantum memories is analyzed as a function of the pulse widths and phase properties of tailored optical field waveforms used to write in and read out broadband photon wave packets. Based on this analysis, we quantify the tradeoff between the readout contrast and the speed of such memories. Off-resonance coherent four-wave mixing is shown to provide a source of noise photons, lowering the readout contrast in broadband Raman quantum memories. This noise cannot be suppressed by phase matching, but can be radically reduced with a suitable polarization arrangement and proper field-waveform tailoring.
Innovative Biocatalysts as Tools to Detect and Inactivate Nerve Agents
Authors: Porzio Elena , Bettazzi Francesca , Mandrich Luigi , Del Giudice Immacolata , Restaino Odile F. , Laschi Serena , Febbraio Ferdinando , De Luca Valentina , Borzacchiello Maria G. , Carusone Teresa M. , Worek Franz , Pisanti Antonio , Porcaro Piero , Schiraldi Chiara , De Rosa Mario , Palchetti Ilaria , Manco Giuseppe
Published: September 2018

Pesticides and warfare nerve agents are frequently organophosphates (OPs) or related compounds. Their acute toxicity highlighted more than ever the need to explore applicable strategies for the sensing, decontamination and/or detoxification of these compounds. Herein, we report the use of two different thermostable enzyme families capable to detect and inactivate OPs. In particular, mutants of carboxylesterase-2 from Alicyclobacillus acidocaldarius and of phosphotriesterase-like lactonases from Sulfolobus solfataricus and Sulfolobus acidocaldarius, have been selected and assembled in an optimized format for the development of an electrochemical biosensor and a decontamination formulation, respectively. The features of the developed tools have been tested in an ad-hoc fabricated chamber, to mimic an alarming situation of exposure to a nerve agent. Choosing ethyl-paraoxon as nerve agent simulant, a limit of detection (LOD) of 0.4 nM, after 5 s of exposure time was obtained. Furthermore, an optimized enzymatic formulation was used for a fast and efficient environmental detoxification (>99%) of the nebulized nerve agent simulants in the air and on surfaces. Crucial, large-scale experiments have been possible thanks to production of grams amounts of pure (>90%) enzymes.
Hypophosphatemia Regulates Molecular Mechanisms of Circadian Rhythm
Authors: Noguchi Takashi , Hussein Amira I. , Horowitz Nina , Carroll Deven , Gower Adam C. , Demissie Serkalem , Gerstenfeld Louis C.
Published: September 2018

Transcriptomic analysis showed that the central circadian pathway genes had significantly altered expression in fracture calluses from mice fed a low phosphate diet. This led us to hypothesize that phosphate deficiency altered the circadian cycle in peripheral tissues. Analysis of the expression of the central clock genes over a 24–36 hour period in multiple peripheral tissues including fracture callus, proximal tibia growth plate and cardiac tissues after 12 days on a low phosphate diet showed higher levels of gene expression in the hypophosphatemia groups (p < 0.001) and a 3 to 6 hour elongation of the circadian cycle. A comparative analysis of the callus tissue transcriptome genes that were differentially regulated by hypophosphatemia with published data for the genes in bone that are diurnally regulated identified 1879 genes with overlapping differential regulation, which were shown by ontology assessment to be associated with oxidative metabolism and apoptosis. Network analysis of the central circadian pathway genes linked their expression to the up regulated expression of the histone methyltransferase gene EZH2, a gene that when mutated in both humans and mice controls overall skeletal growth. These data suggest that phosphate is an essential metabolite that controls circadian function in both skeletal and non skeletal peripheral tissues and associates its levels with the overall oxidative metabolism and skeletal growth of animals.
Critical steps in clinical shotgun metagenomics for the concomitant detection and typing of microbial pathogens
Authors: Couto Natacha , Schuele Leonard , Raangs Erwin C. , Machado Miguel P. , Mendes Catarina I. , Jesus Tiago F. , Chlebowicz Monika , Rosema Sigrid , Ramirez Mário , Carriço João A. , Autenrieth Ingo B. , Friedrich Alex W. , Peter Silke , Rossen John W.
Published: September 2018

High throughput sequencing has been proposed as a one-stop solution for diagnostics and molecular typing directly from patient samples, allowing timely and appropriate implementation of measures for treatment, infection prevention and control. However, it is unclear how the variety of available methods impacts the end results. We applied shotgun metagenomics on diverse types of patient samples using three different methods to deplete human DNA prior to DNA extraction. Libraries were prepared and sequenced with Illumina chemistry. Data was analyzed using methods likely to be available in clinical microbiology laboratories using genomics. The results of microbial identification were compared to standard culture-based microbiological methods. On average, 75% of the reads corresponded to human DNA, being a major determinant in the analysis outcome. None of the kits was clearly superior suggesting that the initial ratio between host and microbial DNA or other sample characteristics were the major determinants of the proportion of microbial reads. Most pathogens identified by culture were also identified through metagenomics, but substantial differences were noted between the taxonomic classification tools. In two cases the high number of human reads resulted in insufficient sequencing depth of bacterial DNA for identification. In three samples, we could infer the probable multilocus sequence type of the most abundant species. The tools and databases used for taxonomic classification and antimicrobial resistance identification had a key impact on the results, recommending that efforts need to be aimed at standardization of the analysis methods if metagenomics is to be used routinely in clinical microbiology.
The Atlantic salmon (Salmo salar) antimicrobial peptide cathelicidin-2 is a molecular host-associated cue for the salmon louse (Lepeophtheirus salmonis)
Authors: Núñez-Acuña Gustavo , Gallardo-Escárate Cristian , Fields David M. , Shema Steven , Skiftesvik Anne Berit , Ormazábal Ignacio , Browman Howard I.
Published: September 2018

Chemical signals are a key element of host-parasite interactions. In marine ecosystems, obligate ectoparasites, such as sea lice, use chemical cues and other sensory signals to increase the probability of encountering a host and to identify appropriate hosts on which they depend to complete their life cycle. The chemical compounds that underlie host identification by the sea lice are not fully described or characterized. Here, we report a novel compound - the Atlantic salmon (Salmo salar) antimicrobial peptide cathelicidin-2 (Cath-2) – that acts as an activation cue for the marine parasitic copepod Lepeophtheirus salmonis. L. salmonis were exposed to 0, 7, 70 and 700 ppb of Cath-2 and neural activity, swimming behaviour and gene expression profiles of animals in response to the peptide were evaluated. The neurophysiological, behavioural and transcriptomic results were consistent: L. salmonis detects Cath-2 as a water-soluble peptide released from the skin of salmon, triggering chemosensory neural activity associated with altered swimming behaviour of copepodids exposed to the peptide, and chemosensory-related genes were up-regulated in copepodids exposed to the peptide. L. salmonis are activated by Cath-2, indicating a tight link between this peptide and the salmon louse chemosensory system.
X-ray structure of full-length human RuvB-Like 2 – mechanistic insights into coupling between ATP binding and mechanical action
Authors: Silva Sara T. N. , Brito José A. , Arranz Rocío , Sorzano Carlos Óscar S. , Ebel Christine , Doutch James , Tully Mark D. , Carazo José-María , Carrascosa José L. , Matias Pedro M. , Bandeiras Tiago M.
Published: September 2018

RuvB-Like transcription factors function in cell cycle regulation, development and human disease, such as cancer and heart hyperplasia. The mechanisms that regulate adenosine triphosphate (ATP)-dependent activity, oligomerization and post-translational modifications in this family of enzymes are yet unknown. We present the first crystallographic structure of full-length human RuvBL2 which provides novel insights into its mechanistic action and biology. The ring-shaped hexameric RuvBL2 structure presented here resolves for the first time the mobile domain II of the human protein, which is responsible for protein-protein interactions and ATPase activity regulation. Structural analysis suggests how ATP binding may lead to domain II motion through interactions with conserved N-terminal loop histidine residues. Furthermore, a comparison between hsRuvBL1 and 2 shows differences in surface charge distribution that may account for previously described differences in regulation. Analytical ultracentrifugation and cryo electron microscopy analyses performed on hsRuvBL2 highlight an oligomer plasticity that possibly reflects different physiological conformations of the protein in the cell, as well as that single-stranded DNA (ssDNA) can promote the oligomerization of monomeric hsRuvBL2. Based on these findings, we propose a mechanism for ATP binding and domain II conformational change coupling.
A new method for discovering EMAST sequences in animal models of cancer
Authors: Bhaskaran Nitya , Luu Jennifer , Kelley Scott T. , Khan Mohammad W. , Mamindla Priyadarshini , McGuire Kathleen L.
Published: September 2018

Elevated Microsatellite Alterations at Selected Tetranucleotide repeats (EMAST) occur in up to 60% of colorectal cancers and may associate with aggressive and advanced disease in patients. Although EMAST occurs in many cancer types, current understanding is limited due to the lack of an animal model. Reported here is the design and implementation of an algorithm for detecting EMAST repeats in mice. This algorithm incorporates properties of known human EMAST sequences to identify repeat sequences in animal genomes and was able to identify EMAST-like sequences in the mouse. Seven of the identified repeats were analyzed further in a colon cancer mouse model and six of the seven displayed EMAST instability characteristic of that seen in human colorectal cancers. In conclusion, the algorithm developed successfully identified EMAST repeats in an animal genome and, for the first time, EMAST has been shown to occur in a mouse model of colon cancer.
Low survival of strongly footed pheasants may explain constraints on lateralization
Authors: Whiteside Mark A. , Bess Mackenzie M. , Frasnelli Elisa , Beardsworth Christine E. , Langley Ellis J. G. , van Horik Jayden O. , Madden Joah R.
Published: September 2018

Brain lateralization is considered adaptive because it leads to behavioral biases and specializations that bring fitness benefits. Across species, strongly lateralized individuals perform better in specific behaviors likely to improve survival. What constrains continued exaggerated lateralization? We measured survival of pheasants, finding that individuals with stronger bias in their footedness had shorter life expectancies compared to individuals with weak biases. Consequently, weak, or no footedness provided the highest fitness benefits. If, as suggested, footedness is indicative of more general brain lateralization, this could explain why continued brain lateralization is constrained even though it may improve performance in specific behaviors.
Noninvasive assessment of characteristics of novel anti-HER2 antibodies by molecular imaging in a human gastric cancer xenograft-bearing mouse model
Authors: Kuo Wei-Ying , Lin Jia-Jia , Hsu Hung-Ju , Chen Hong-Sen , Yang An-Suei , Wu Chun-Yi
Published: September 2018

Human epidermal growth factor receptor 2 (HER2) overexpression occurs in various types of cancers. Regarding the anti-HER2 targeted therapies showed superior treatment outcomes in several (pre)clinical studies, we used multimodality image to rapidly select novel HER2-targeting antibodies for further therapeutics development. The four anti-HER2 antibodies (H32 IgG, 75 IgG, 61 IgG, and trastuzumab) labeled with either In-111 or a DyLight680 fluorescent dye were applied to perform cellular uptake, endocytosis, optical/microSPECT/CT imaging and biodistribution studies. In vitro and in vivo relative effectiveness of these antibodies were also compared in an N87 gastric cancer xenograft model. The internalized radioactivity of [111In]61 IgG in N87 cells increased from 33% at 12 hr to 56% at 48 hr after incubation, while the majority of other antibodies stayed on the cell membranes. Among these antibodies, 61 IgG showed the highest accumulation in tumors with the tumor-to-muscle ratio (T/M) of 131 ± 61.4 and 19.13 ± 3.42 conducted by IVIS and microSPECT/CT, respectively. We demonstrated that multimodality imaging is a reliable approach for selecting potential antibodies and found that 61 IgG manifested significant tumor accumulation with elevated internalization rate thus could be a suitable candidate for further development of new HER2-targeted therapies.
Fabrication and Characterization of Glucose Biosensors by Using Hydrothermally Grown ZnO Nanorods
Authors: Ridhuan Nur Syafinaz , Abdul Razak Khairunisak , Lockman Zainovia
Published: September 2018

Highly oriented ZnO nanorod (NR) arrays were fabricated on a seeded substrate through a hydrothermal route. The prepared ZnO nanorods were used as an amperometric enzyme electrode, in which glucose oxidase (GOx) was immobilised through physical adsorption. The modified electrode was designated as Nafion/GOx/ZnO NRs/ITO. The morphology and structural properties of the fabricated ZnO nanorods were analysed using field-emission scanning electron microscope and X-ray diffractometer. The electrochemical properties of the fabricated biosensor were studied by cyclic voltammetry and amperometry. Electrolyte pH, electrolyte temperature and enzyme concentration used for immobilisation were the examined parameters influencing enzyme activity and biosensor performance. The immobilised enzyme electrode showed good GOx retention activity. The amount of electroactive GOx was 7.82 × 10−8mol/cm2, which was relatively higher than previously reported values. The Nafion/GOx/ZnO NRs/ITO electrode also displayed a linear response to glucose ranging from 0.05 mM to 1 mM, with a sensitivity of 48.75 µA/mM and a low Michaelis–Menten constant of 0.34 mM. Thus, the modified electrode can be used as a highly sensitive third-generation glucose biosensor with high resistance against interfering species, such as ascorbic acid, uric acid andL-cysteine. The applicability of the modified electrode was tested using human blood samples. Results were comparable with those obtained using a standard glucometer, indicating the excellent performance of the modified electrode.
Suppression of GPR56 expression by pyrrole-imidazole polyamide represents a novel therapeutic drug for AML with high EVI1 expression
Authors: Saha Hasi Rani , Kaneda-Nakashima Kazuko , Shimosaki Shunsuke , Suekane Akira , Sarkar Bidhan , Saito Yusuke , Ogoh Honami , Nakahata Shingo , Inoue Kentaro , Watanabe Takayoshi , Nagase Hiroki , Morishita Kazuhiro
Published: September 2018

G protein-coupled receptor 56 (GPR56) is highly expressed in acute myeloid leukemia (AML) cells with high EVI1 expression (EVI1high AML). Because GPR56 is a transcriptional target of EVI1 and silencing of GPR56 expression induces apoptosis, we developed a novel drug to suppress GPR56 expression in EVI1high AML cells. For this purpose, we generated pyrrole-imidazole (PI) polyamides specific to GPR56 (PIP/56-1 or PIP/56-2) as nuclease-resistant novel compounds that interfere with the binding of EVI1 to the GPR56 promoter in a sequence-specific manner. Treatment of EVI1high AML cell lines (UCSD/AML1 and Kasumi-3) with PIP/56-1 or PIP/56-2 effectively suppressed GPR56 expression by inhibiting binding of EVI1 to its promoter, leading to suppression of cell growth with increased rates of apoptosis. Moreover, intravenous administration of PIP/56-1 into immunodeficient Balb/c-RJ mice subcutaneously transplanted with UCSD/AML1 cells significantly inhibited tumor growth and extended survival. Furthermore, organ infiltration by leukemia cells in immunodeficient Balb/c-RJ mice, which were intravenously transplanted using UCSD/AML1 cells, was successfully inhibited by PIP/56-1 treatment with no apparent effects on murine hematopoietic cells. In addition, PIP treatment did not inhibit colony formation of human CD34+ progenitor cells. Thus, PI polyamide targeting of GPR56 using our compound is promising, useful, and safe for the treatment of EVI1high AML.
Iodine determination in table salts by digital images analysis
Authors: de O. Costa Geovanna , Feiteira Fernanda N. , de M. Schuenck Hanna , Pacheco Wagner F.
Published: September 2018

For human health reasons the World Health Organization (WHO) stated in 2014 that the amount of iodine present on table salts should lie within the range of 15 to 65 mg per kilogram of salt, depending on the salt intake levels presented in each population.
A biocompatible and cathepsin B sensitive nanoscale system of dendritic polyHPMA-gemcitabine prodrug enhances antitumor activity markedly
Authors: Dai Yan , Ma Xuelei , Zhang Yanhong , Chen Kai , Tang James Z. , Gong Qiyong , Luo Kui
Published: September 2018

A stimuli-responsive biodegradable dendritic prodrug synthesized via one-pot RAFT polymerization demonstrated a marked enhancement in antitumor efficacy and minimal side effects on 4T1 breast tumors.
Challenges, mitigation strategies and perspectives in development of zinc-electrode materials and fabrication for rechargeable zinc–air batteries
Authors: Yi Jin , Liang Pengcheng , Liu Xiaoyu , Wu Kai , Liu Yuyu , Wang Yonggang , Xia Yongyao , Zhang Jiujun
Published: September 2018

A comprehensive understanding of the challenges in zinc-electrode materials and fabrication that limit the continuous development of rechargeable zinc–air batteries.
Toward computational and experimental characterisation for risk assessment of metal oxide nanoparticles
Authors: Escorihuela Laura , Martorell Benjamí , Rallo Robert , Fernández Alberto
Published: September 2018

In silicomethods provide an alternative and reliable route for the toxicity evaluation of metal oxide nanoparticles.
Cd induces G2/M cell cycle arrest by up-regulating miR-133b via directly targeting PPP2R2D in L02 hepatocytes
Authors: Zhang Yujing , Xiao Fang , Zhong Caigao , Zeng Ming , Zou Lianhong
Published: September 2018

Previous research has shown that cadmium (Cd), which accumulates primarily in the liver and kidneys, could cause cell cycle arrest in various cell types. In the present study, the effect of Cd on the cell cycle progression of hepatocytes and the underlying mechanisms were investigated. Our results showed that Cd inhibited the growth and proliferation of L02 hepatocytes. Further study revealed that Cd significantly induced G2-phase cell cycle arrest accompanied by an overproduction of reactive oxygen species (ROS). Cd-induced G2-phase arrest could be prevented by inhibiting ROS with the use of antioxidant Trolox. Additionally, treatment with Cd induced an increase in the expression of miR-133b, which could be reversed with Trolox pretreatment. Moreover, miR-133b was shown to regulate PPP2R2D expression by binding to the 3′-untranslated region (UTR) of PPP2R2D mRNA. We also found that treatment with Cd decreased the expression of PPP2R2D, and inhibition of PPP2R2D expression by siRNA partially aggravated Cd-induced cell cycle arrest. By artificially increasing the expression of the protein phosphatase 2A-B55δ subunit (PP2A-B55δ, encoded by the PPP2R2D gene), we confirmed that PPP2R2D can be regulated by miR-133b in Cd-treated cells, and the G2-phase arrest effect could be suppressed by PP2A-B55δ. Collectively, these findings indicated that Cd increased ROS and induced the expression of miR-133b, which consequently inhibited the expression of PPP2R2D and led to G2-phase arrest in L02 hepatocytes. This study provides novel insights into the molecular mechanisms of Cd-induced cell cycle arrest.
Litchi-peel-like hierarchical hollow copper-ceria microspheres: aerosol-assisted synthesis and high activity and stability for catalytic CO oxidation
Authors: Li Wenge , Hu Yanjie , Jiang Hao , Jiang Nan , Bi Wei , Li Chunzhong
Published: September 2018

Litchi-peel-like hierarchical hollow copper-ceria microspheres with highly dispersed CuOx and steps exhibit remarkable catalytic activity and stability for CO oxidation.
“Transformed” Fe3S4 tetragonal nanosheets: a high-efficiency and body-clearable agent for magnetic resonance imaging guided photothermal and chemodynamic synergistic therapy
Authors: Guan Guoqiang , Wang Xin , Li Bo , Zhang Wenlong , Cui Zhe , Lu Xinwu , Zou Rujia , Hu Junqing
Published: September 2018

The PVP coated Fe3S4 tetragonal nanosheets could be employed to realize magnetic resonance imaging guided photothermal/chemodynamic therapy and body-clearance without appreciable toxic side effects.
Ruthenium-catalyzed tandem annulation/arylation for the synthesis of unsymmetrical bis(heteroaryl)methanes
Authors: Samanta Sadhanendu , Hajra Alakananda
Published: September 2018

A new Ru-catalyzed tandem annulation/arylation strategy has been developed to afford unsymmetrical bis(heteroaryl)methanes containing furan and indole as well as indole and imidazopyridine moieties in high yields.
Isocyanurate formation during rigid polyurethane foam assembly: a mechanistic study based on in situ IR and NMR spectroscopy
Authors: Al Nabulsi A. , Cozzula D. , Hagen T. , Leitner W. , Müller T. E.
Published: September 2018

Unravelling the role and working principle of the catalyst.
MALDI-LID-ToF/ToF analysis of statistical and diblock polyacrylate copolymers
Authors: Town James S. , Jones Glen R. , Haddleton David M.
Published: September 2018

We report the use of MALDI-LID-ToF/ToF utilising the laser induced dissociation (LID) fragmentation technique, which has been almost exclusively applied to protein/peptide analysis to date.
Macroscopic and microscopic investigation of uranium elimination by Ca–Mg–Al-layered double hydroxide supported nanoscale zero valent iron
Authors: Pang Hongwei , Wu Yihan , Huang Shuyi , Ding Congcong , Li Shun , Wang Xiangxue , Yu Shujun , Chen Zhongshan , Song Gang , Wang Xiangke
Published: September 2018

Ca–Mg–Al-LDH/nZVI nanocomposites showed excellent U(vi) removal performance from aqueous solutions through the coordination of reduction and adsorption reactions.
Synthesis of zeolitic imidazolate framework-8 on polyester fiber for PM2.5 removal
Authors: Zhang Yongyong , Jia Ying , Hou Li'an
Published: September 2018

Zeolitic imidazolate framework-8 (ZIF-8) was introduced on the surface of fibers of a non-woven fabric made of polyethylene terephthalate (PET).
Molecular engineering of the bio/nano-interface for enzymatic electrocatalysis in fuel cells
Authors: Le Goff Alan , Holzinger Michael
Published: September 2018

The fascinating topic of converting chemical energy into electric power using biological catalysts, called enzymes, and sustainable fuels motivates a large community of scientists to develop enzymatic fuel cells.
Role of Stefan–Maxwell fluxes in the dynamics of concentrated electrolytes
Authors: Balu Bhavya , Khair Aditya S.
Published: September 2018

This theoretical analysis quantifies the effect of coupled ionic fluxes on the charging dynamics of an electrochemical cell.
Super tough and strong self-healing elastomers based on polyampholytes
Authors: Peng Yan , Zhao Lijuan , Yang Changyue , Yang Yi , Song Cheng , Wu Qi , Huang Guangsu , Wu Jinrong
Published: September 2018

A high performance self-healing elastomer (HiSHE) is fabricated by copolymerization of a neutral monomer and a pair of oppositely charged monomers.
Plasma surface modification of polymers for sensor applications
Authors: Alemán Carlos , Fabregat Georgina , Armelin Elaine , Buendía Jorge J. , Llorca Jordi
Published: September 2018

Polymeric sensors play an increasingly important role in monitoring the environment we live in, providing relevant information for a host of applications.
A highly efficient and heat-resistant electromagnetic interference shielding carbon nanotube/poly(phenylene sulfide) composite via sinter molding
Authors: Zhang Xiao-Peng , Jia Li-Chuan , Zhang Gang , Yan Ding-Xiang , Li Zhong-Ming
Published: September 2018

A highly efficient electromagnetic interference shielding CNT/PPS composite is realized.
Experimental extreme high‐squint SAR target imaging
Authors: Burfeindt M. , Orgusaar R.
Published: September 2018

An experimental study of extreme high‐squint (i.e. forward‐looking) synthetic aperture radar (SAR) is presented. Experimental data collected against a distributed complex target are successfully focused using the backprojection algorithm. Interferometric SAR processing is then performed in order to overcome left‐right ambiguity and estimate constituent scatterer Cartesian coordinates.
Transient current control for a step load change in a dual‐active‐bridge converter
Authors: Sun Chuan , Li Xiaodong , Zhou Sheng‐Zhi
Published: September 2018

To deal with a command of step load change for a dual‐active‐bridge converter, a transient current control with a multi‐phase‐shift gating scheme is needed. By selecting a reference signal with a floating position, the effective transient current control can be achieved by moving multiple voltage edges in sequence, which would fulfil the step transition of the load level in a fast and smooth manner. Although the analysis is derived using triple‐phase‐shift schemes, the proposed control can also be applied to other multi‐phase‐shift schemes, such as extended‐phase‐shit and dual‐phase‐shift scheme. An experimental test validated the correctness and effectiveness of the proposed transient current control.
Event‐triggered sliding mode control for discrete‐time singular system
Authors: Fan Xiaofei , Zhang Qingling , Ren Junchao
Published: September 2018

This study focuses on the discrete‐time sliding mode control (SMC) based on event‐triggered approach for discrete‐time singular system. The purpose is to design a SMC law under event‐triggered to ensure that the discrete‐time singular system is admissible. A novel event‐triggered sliding mode surface is constructed, and a sufficient condition, in the form of linear matrix inequality (LMI), is investigated to guarantee the admissibility of the discrete‐time singular system. One can verify this condition by utilising the toolbox YALMIP of MATLAB. In addition, the expected controller gain matrix can be represented by a feasible solution of LMI. Then, based on the above solved sliding mode controller gain, a new discrete‐time event‐triggered SMC law is constructed to ensure that the discrete‐time singular system can be driven onto the sliding surface in finite time and then is maintained there for all subsequent time. Finally, three examples are presented to illustrate the effectiveness of the theoretical results.
Robust visual tracking with adaptive initial configuration and likelihood landscape analysis
Authors: Kim Guisik , Kwon Junseok
Published: September 2018

Here, the authors propose a novel tracking algorithm that can automatically modify the initial configuration of a target to improve the tracking accuracy in subsequent frames. To achieve this goal, the authors’ method analyses the likelihood landscape (LL) for the image patch described by the initial configuration. A good configuration has a unimodal distribution with a steep shape in the LL. Using the LL analysis, the authors’ method improves the initial configuration, resulting in more accurate tracking results. The authors improve the conventional LL analysis based on two ideas. First, the authors’ method analyses the LL in the RGB space rather than the grey space. Second, the method introduces an additional criterion for a good configuration: a high likelihood value at the mode. The authors further enhance their method through post‐processing of the visual tracking results at each frame, where the estimated bounding boxes are modified by the LL analysis. The experimental results demonstrate that the authors’ advanced LL analysis helps improve the tracking accuracy of several baseline trackers on a visual tracking benchmark data set. In addition, the authors’ simple post‐processing technique significantly enhances the visual tracking performance in terms of precision and success rate.
Dimensionality reduction based on determinantal point process and singular spectrum analysis for hyperspectral images
Authors: Chen Weizhao , Yang Zhijing , Cao Faxian , Yan Yijun , Wang Meilin , Qing Chunmei , Cheng Yongqiang
Published: September 2018

Dimensionality reduction is of high importance in hyperspectral data processing, which can effectively reduce the data redundancy and computation time for improved classification accuracy. Band selection and feature extraction methods are two widely used dimensionality reduction techniques. By integrating the advantages of the band selection and feature extraction, the authors propose a new method for reducing the dimension of hyperspectral image data. First, a new and fast band selection algorithm is proposed for hyperspectral images based on an improved determinantal point process (DPP). To reduce the amount of calculation, the dual‐DPP is used for fast sampling representative pixels, followed by k‐nearest neighbour‐based local processing to explore more spatial information. These representative pixel points are used to construct multiple adjacency matrices to describe the correlation between bands based on mutual information. To further improve the classification accuracy, two‐dimensional singular spectrum analysis is used for feature extraction from the selected bands. Experiments show that the proposed method can select a low‐redundancy and representative band subset, where both data dimension and computation time can be reduced. Furthermore, it also shows that the proposed dimensionality reduction algorithm outperforms a number of state‐of‐the‐art methods in terms of classification accuracy.
Spatialising uncertainty in image segmentation using weakly supervised convolutional neural networks: a case study from historical map processing
Authors: Uhl Johannes H. , Leyk Stefan , Chiang Yao‐Yi , Duan Weiwei , Knoblock Craig A.
Published: September 2018

Convolutional neural networks (CNNs) such as encoder–decoder CNNs have increasingly been employed for semantic image segmentation at the pixel‐level requiring pixel‐level training labels, which are rarely available in real‐world scenarios. In practice, weakly annotated training data at the image patch level are often used for pixel‐level segmentation tasks, requiring further processing to obtain accurate results, mainly because the translation invariance of the CNN‐based inference can turn into an impeding property leading to segmentation results of coarser spatial granularity compared with the original image. However, the inherent uncertainty in the segmented image and its relationships to translation invariance, CNN architecture, and classification scheme has never been analysed from an explicitly spatial perspective. Therefore, the authors propose measures to spatially visualise and assess class decision confidence based on spatially dense CNN predictions, resulting in continuous decision confidence surfaces. They find that such a visual‐analytical method contributes to a better understanding of the spatial variability of class score confidence derived from weakly supervised CNN‐based classifiers. They exemplify this approach by incorporating decision confidence surfaces into a processing chain for the extraction of human settlement features from historical map documents based on weakly annotated training data using different CNN architectures and classification schemes.
Automatic detection and segmentation of optic disc and fovea in retinal images
Authors: Chalakkal Renoh Johnson , Abdulla Waleed Habib , Thulaseedharan Sinumol Sukumaran
Published: September 2018

Feature extraction from retinal images is gaining popularity worldwide as many pathologies are proved having connections with these features. Automatic detection of these features makes it easier for the specialist ophthalmologists to analyse them without spending exhaustive time to segment them manually. The proposed method automatically detects the optic disc (OD) using histogram‐based template matching combined with the maximum sum of vessel information in the retinal image. The OD region is segmented by using the circular Hough transform. For detecting fovea, the retinal image is uniformly divided into three horizontal strips and the strip including the detected OD is selected. Contrast of the horizontal strip containing the OD region is then enhanced using a series of image processing steps. The macula region is first detected in the OD strip using various morphological operations and connected component analysis. The fovea is located inside this detected macular region. The proposed method achieves an OD detection accuracy over 95% upon testing on seven public databases and on our locally developed database, University of Auckland Diabetic Retinopathy database (UoA‐DR). The average OD boundary segmentation overlap score, sensitivity and fovea detection accuracy achieved are 0.86, 0.968 and 97.26% respectively.
Dynamic integration and online evaluation of vision‐based lane detection algorithms
Authors: Xing Yang , Lv Chen , Wang Huaji , Cao Dongpu , Velenis Efstathios
Published: September 2018

Lane detection techniques have been widely studied in the last two decades and applied in many advance driver assistance systems. However, the development of a robust lane detection system, which can deal with various road conditions and efficiently evaluate its detection results in real time, is still of great challenge. In this study, a vision‐based lane detection system with dynamic integration and online evaluation is proposed. To increase the robustness of the lane detection system, the integration system dynamically processes two lane detection modules. First, a primary lane detection module is designed based on the steerable filter and Hough transform algorithm. Then, a secondary algorithm, which combines the Gaussian mixture model for image segmentation and random sample consensus for lane model fitting, will be activated when the primary algorithm encounters a low detection confidence. To detect the colour and line style of the ego lanes and evaluate the lane detection system in real time, a lane sampling and voting technique is proposed. By combining the sampling and voting system system with prior lane geometry knowledge, the evaluation system can efficiently recognise the false detections. The system works robustly in various complex situations (e.g. shadows, night, and lane missing scenarios) with a monocular camera.
Driver intention based coordinate control of regenerative and plugging braking for electric vehicles with in‐wheel PMSMs
Authors: Li Wenfei , Du Haiping , Li Weihua
Published: September 2018

Electric vehicles have been the focus of the automotive industry in recent years. However, relatively small driving range of electric vehicles makes it not be broadly adopted in the market. Regenerative braking is one of the most effective ways to extend the endurance of electric vehicles. To sufficiently utilise the regenerative braking of electric vehicles and explore the potential of the electric motor plugging braking capability to simplify the braking system structure and reduce the cost, a new braking strategy based on the driver's braking intention and motor working characteristics is proposed. Driver's braking intention is classified as the emergency braking and the normal braking. In the case of normal braking, model predictive control (MPC) is used to express driver's braking intention. By adjusting the weight of the MPC cost function, different braking intentions can be achieved. This strategy is able to achieve as much as possible braking energy recovery without violating the driver's braking intention. In the case of the emergency braking, the sliding mode based optimal slip ratio control is adopted and it is able to obtain the shortest braking distance. In order to validate the effectiveness of the proposed approach, numerical simulations on a quarter‐vehicle braking model are tested.
Dielectric characterisation of Fe3 P nanoparticles based ester oil
Authors: Khan Qasim , Hussain Rashid , Khan Asfar Ali
Published: September 2018

The insulation as the root source of failure and ageing assessor makes it a crucial point for any power equipment design. The transformer's insulation requires an efficient dielectric fluid that acts as an ideal electrical insulant and better thermal transporter. The objective of attaining that idealism in dielectric medium leads to the addition of solvents (i.e. additive and other fluids) in the conventional medium as one of its approach. This study presents addition of new magnetic nanoparticle iron phosphide (Fe3 P) in insulating oil to achieve improved dielectric strength and withstand capability of the same conventional oil. A comparative study of nanofluids with different concentrations of nanofluids based on different insulating medium (i.e. synthetic ester and natural ester) has been performed. The concentration of additives and role of surfactant positively influences the dielectric characteristics of the base oil. The increase in breakdown strength is observed with a slight concentration of Fe3 P nanoparticles added in the insulating medium.
Single‐phase hybrid‐H6 transformerless PV grid‐tied inverter
Authors: Ma Lan , Xu Hongbing , Huang Alex Q. , Wang Xiaodong , Zou Jianxiao
Published: September 2018

Transformerless inverter for grid‐tied photovoltaic (PV) system has been widely used due to lower cost, higher efficiency and lighter weight. Various transformerless inverter topologies have been proposed to meet the safety requirement of low leakage current and obtain the reactive power capability. To get better performance, a novel transformerless hybrid‐H6 inverter with an improved modulation technique is proposed in this study. By adopting the improved modulation technique, two symmetry paths are realised to share the current during the freewheeling mode. Thus, without paralleling any additional capacitors to the switch, the inverter can reduce the influence of junction capacitance on common mode voltage naturally which results in mitigating the leakage current issue. Thanks to the dead time reduction through the improved modulation, the qualities of output waveforms are improved. Moreover, reactive power control is achieved without any modification of the inverter structure. Finally, a 1 kW prototype is simulated and tested to verify the theoretical analysis of this study. Not only the reactive power capability is obtained for the proposed inverter, but also the small common mode voltage fluctuation is achieved at the same time. In addition, the total harmonic distortion of the current is decreased by more than 1.7%.
Single chip design for detection and recovery of series LED open/short fault tolerance circuit
Authors: Hsia Shih‐Chang , Ciou Jyun‐Jia
Published: September 2018

Light emitting diode (LED) lighting is widely used in current. However, lighting robustness is low in a series loop since the lighting shuts down as one LED fails. This study proposes a power chip for fault detection and isolation for enhancement of LED's fault‐withstanding capability. The chip can automatically detect the failed LEDs and bypass them, and let others continue to work. The authors implemented four bypass loops using a power metal oxide semiconductor (MOS) on the single chip. This chip can drive 1 A with 4‐bit current dimming, which includes four bypass power P‐type MOSs, one power N‐type MOS, schedule controller, level shifter and over voltage protection. The schedule controller with a state machine can quickly find which one LED fail and recover it soon. The prototyping chip was designed using TSMC 0.25 μm, which is the second generator high‐voltage technology, and the resulting chip area with pads is only 1.3 × 1.7 mm2. The chip had been successfully implemented and measured to drive and bypass four LED components or modules.
Modified‐adaptive pulse compression repair algorithm based on post‐processing for eclipsing effects
Authors: Shokooh Reza Kayvan , Okhovvat Majid
Published: September 2018

The problem of resolving and detecting masked weak moving targets in the presence of fast strong targets is particularly difficult due to side lobes produced by ordinary signal processing techniques and becomes even harder when a partially returned signal is received. Where return signals coincide with the transmission of a pulse, pulse eclipsing can occur which results in detection performance loss. In this approach, the output of a matched filter (MF) was utilised as the input to the post‐processing reiterative minimum mean square error (RMMSE) algorithm. The mismatch created in the received signal by Doppler phase shift and pulse eclipsing degrades adaptive pulse compression (APC) filter performance. This study presents a new method to account for both Doppler phase shift and pulse eclipsing using the modified APC repair (MAPCR) algorithm. Simulation results show that the proposed MAPCR algorithm mitigates the eclipsing effect and reduces range side lobes significantly, in addition to providing improved range resolution. The authors compare their results for single point and extended targets placed in the eclipsed region with other algorithms such as the standard MF, pulse compression repair, APC‐eclipsing repair and MF‐RMMSE.
Research on pulse power based on saturable pulse transformer and magnetic switch
Authors: Rong Li , Rong Qi
Published: September 2018

A method of using saturable pulse transformer (SPT) in series with a magnetic switch is adopted in research on high power pulsed power miniaturisation and high repeat frequency in this study. SPT not only plays a part in boosting, but also plays a part in pulse compression. In this case, a stage magnetic pulse compression can be omitted, and the volume and weight of the system are both reduced. First, the topology of pulse power supply is presented, and working principle of the topology is introduced in detail. At the same time, the dynamic process of de‐magnetic saturation control circuit of magnetic switch is analysed. Second, the selection principle of magnetic core of SPT and magnetic switch is given, and the core used in this study is modelled in PSPICE. At last, the whole circuit is modelled and simulated in PSPICE. Simulation results show that the proposed scheme is feasible, which has a good theoretical guidance for the subsequent experimental work.
(121514) 1999 UJ7: A primitive, slow-rotating Martian Trojan
Authors: Borisov G. , Christou A. A. , Colas F. , Bagnulo S. , Cellino A. , Dell’Oro A.
Published: September 2018

Aims. The goal of this investigation is to determine the origin and surface composition of the asteroid (121514) 1999 UJ7, the only currently known L4 Martian Trojan asteroid.

Methods. We have obtained visible reflectance spectra and photometry of 1999 UJ7 and compared the spectroscopic results with the spectra of a number of taxonomic classes and subclasses. A light curve was obtained and analysed to determine the asteroid spin state.

Results. The visible spectrum of 1999 UJ7 exhibits a negative slope in the blue region and the presence of a wide and deep absorption feature centred around ~0.65 μm. The overall morphology of the spectrum seems to suggest a C-complex taxonomy. The photometric behaviour is fairly complex. The light curve shows a primary period of 1.936 d, but this is derived using only a subset of the photometric data. The asteroid may be in a non-principal axis rotational state, but our observational coverage is insufficient to draw definitive conclusions.

Conclusions. Although the observed spectral absorption is wider and deeper, this finding may be compatible with the 0.7 μm spectral feature exhibited by some Ch-type asteroids and could possibly be interpreted as diagnostic of the presence of hydrated minerals. The inferred composition of 1999 UJ7 as a primitive object can be consistent with a volatile-rich object originally accreted beyond the snow line of the solar system, and subsequently evolved to reach the inner regions of the solar system.
Recurring obscuration in NGC 3783
Authors: Kaastra J. S. , Mehdipour M. , Behar E. , Bianchi S. , Branduardi-Raymont G. , Brenneman L. , Cappi M. , Costantini E. , De Marco B. , di Gesu L. , Ebrero J. , Kriss G. A. , Mao J. , Peretz U. , Petrucci P.-O. , Ponti G. , Walton D.
Published: September 2018

Context. Obscuration of the continuum emission from active galactic nuclei by streams of gas with relatively high velocity (>1000 km s−1) and column density (>3 × 1025 m−2) has been seen in a few Seyfert galaxies. This obscuration has a transient nature. In December 2016 we witnessed such an event in NGC 3783.

Aims. The frequency and duration of these obscuration events is poorly known. Here we study archival data of NGC 3783 in order to constrain this duty cycle.

Methods. We use archival Chandra/NuSTAR spectra taken in August 2016. We also study the hardness ratio of all Swift XRT spectra taken between 2008 and 2017.

Results. In August 2016, NGC 3783 also showed evidence of obscuration. While the column density of the obscuring material is ten times lower than in December 2016, the opacity is still sufficient to block a significant fraction of the ionising X-ray and extreme ultraviolet photons. From the Swift hardness ratio behaviour we find several other epochs with obscuration. Obscuration with columns >1026 m−2 may take place about half of the time. Also, in archival X-ray data taken by the Advanced Satellite for Cosmology and Astrophysics (ASCA) in 1993 and 1996 we find evidence of obscuration.

Conclusions. Obscuration of the ionising photons in NGC 3783 occurs more frequently than previously thought. This may not always have been recognised due to low-spectral-resolution observations, overly limited spectral bandwidth or confusion with underlying continuum variations.
Evolutionary phases of merging clusters as seen by LOFAR
Authors: Wilber A. , Brüggen M. , Bonafede A. , Rafferty D. , Shimwell T. W. , van Weeren R. J. , Akamatsu H. , Botteon A. , Savini F. , Intema H. , Heino L. , Cuciti V. , Cassano R. , Brunetti G. , Röttgering H. J. A. , de Gasperin F.
Published: September 2018

Massive, merging galaxy clusters often host giant, diffuse radio sources that arise from shocks and turbulence; hence, radio observations can be useful for determining the merger state of a cluster. In preparation for a larger study, we selected three clusters – Abell 1319, Abell 1314, and RXC J1501.3+4220 (Z7215) – making use of the new LOFAR Two-Metre Sky Survey (LoTSS) at 120–168 MHz, and together with archival data, show that these clusters appear to be in pre-merging, merging, and post-merging states, respectively. We argue that Abell 1319 is likely in its pre-merging phase, where three separate cluster components are about to merge. There are no radio haloes nor radio relics detected in this system. Abell 1314 is a highly disturbed, low-mass cluster that is likely in the process of merging. This low-mass system does not show a radio halo, however, we argue that the merger activates mechanisms that cause electron re-acceleration in the large 800 kpc radio tail associated with IC 711. In the cluster Z7215 we discover diffuse radio emission at the cluster centre, and we classify this emission as a radio halo, although it is dimmer and smaller than expected by the radio halo power versus cluster mass correlation. We suggest that the disturbed cluster Z7215 is in its post-merging phase. Systematic studies of this kind over a larger sample of clusters observed with LoTSS will help to constrain the timescales involved in turbulent re-acceleration and the subsequent energy losses of the underlying electrons.