bluuebunny/crossref_metadata_2025 huggingface dataset:
Rapid colorimetric loop-mediated isothermal amplification for hypersensitive point-of-care Staphylococcus aureus enterotoxin A gene detection in milk and pork products
Authors: Srimongkol Grittaya , Ditmangklo Boonsong , Choopara Ilada , Thaniyavarn Jiraporn , Dean Deborah , Kokpol Sirirat , Vilaivan Tirayut , Somboonna Naraporn
Published: May 2020

Staphylococcus aureus strains carrying enterotoxin A gene (sea) causes food poisoning and cannot be distinguished from non-pathogenic strains by the culture method. Here, we developed a rapid, specific and sensitive visual detection of sea using loop-mediated isothermal amplification (LAMP) combined with nanogold probe (AuNP) or styryl dye (STR). LAMP-AuNP and LAMP-STR can detect as low as 9.7 fg (3.2 sea copies) and 7.2 sea copies, respectively, which were lower than PCR (97 fg or 32 sea copies). The excellent performance of these new assays was demonstrated in food samples using crude DNA lysates. While the culture method detected 104 CFU/g in ground pork and 10 CFU/mL in milk in 5–7 days, LAMP-AuNP could detect down to 10 CFU/g for both samples in 27 minutes. Analyzing 80 pork and milk samples revealed that the LAMP-AuNP showed 100% sensitivity, 97–100% specificity and 97.5–100% accuracy, which were superior to the culture method, and comparable to PCR but without requirement of a thermal cycler. Furthermore, our LAMP-AuNP detect sea at a range below the food safety control (<100 CFU/g). The LAMP-STR quantitated sea in 10–1,000 CFU (7.2–720 copies). Our crude DNA lysis combined with LAMP-AuNP/STR present effective point-of-care detection and facilitate appropriate control strategies.
A reconciliation of genome-scale metabolic network model of Zymomonas mobilis ZM4
Authors: Nouri Hoda , Fouladiha Hamideh , Moghimi Hamid , Marashi Sayed-Amir
Published: May 2020

Zymomonas mobilis ZM4 has recently been used for a variety of biotechnological purposes. To rationally enhance its metabolic performance, a reliable genome-scale metabolic network model (GEM) of this organism is required. To this end, we reconstructed a genome-scale metabolic model (iHN446) for Z. mobilis, which involves 446 genes, 859 reactions, and 894 metabolites. We started by first reconciling the existing GEMs previously constructed for Z. mobilis to obtain a draft network. Next, recent gene annotations, up-to-date literature, physiological data and biochemical databases were used to upgrade the network. Afterward, the draft network went through a curative and iterative process of gap-filling by computational tools and manual refinement. The final model was evaluated using experimental data and literature information. We next applied this model as a platform for analyzing the links between transcriptome-flux and transcriptome-metabolome. We found that experimental observations were in agreement with the predicted results from our final GEM. Taken together, this comprehensive model (iHN446) can be utilized for studying metabolism in Z. mobilis and finding rational targets for metabolic engineering applications.
Novel approach for effective removal of methylene blue dye from water using fava bean peel waste
Authors: Bayomie Omar S. , Kandeel Haitham , Shoeib Tamer , Yang Hu , Youssef Noha , El-Sayed Mayyada M. H.
Published: May 2020

Fava bean peels, Vicia faba (FBP) are investigated as biosorbents for the removal of Methylene Blue (MB) dye from aqueous solutions through a novel and efficient sorption process utilizing ultrasonic-assisted (US) shaking. Ultrasonication remarkably enhanced sorption rate relative to conventional (CV) shaking, while maintaining the same sorption capacity. Ultrasonic sorption rate amounted to four times higher than its conventional counterpart at 3.6 mg/L initial dye concentration, 5 g/L adsorbent dose, and pH 5.8. Under the same adsorbent dose and pH conditions, percent removal ranged between 70–80% at the low dye concentration range (3.6–25 mg/L) and reached about 90% at 50 mg/L of the initial dye concentration. According to the Langmuir model, maximum sorption capacity was estimated to be 140 mg/g. A multiple linear regression statistical model revealed that adsorption was significantly affected by initial concentration, adsorbent dose and time. FBP could be successfully utilized as a low-cost biosorbent for the removal of MB from wastewater via US biosorption as an alternative to CV sorption. US biosorption yields the same sorption capacities as CV biosorption, but with significant reduction in operational times.
Label-free plasma proteomics identifies haptoglobin-related protein as candidate marker of idiopathic pulmonary fibrosis and dysregulation of complement and oxidative pathways
Authors: Saraswat Mayank , Joenväärä Sakari , Tohmola Tiialotta , Sutinen Eva , Vartiainen Ville , Koli Katri , Myllärniemi Marjukka , Renkonen Risto
Published: May 2020

Idiopathic pulmonary fibrosis (IPF) is a lung parenchymal disease of unknown cause usually occurring in older adults. It is a chronic and progressive condition with poor prognosis and diagnosis is largely clinical. Currently, there exist few biomarkers that can predict patient outcome or response to therapies. Together with lack of markers, the need for novel markers for the detection and monitoring of IPF, is paramount. We have performed label-free plasma proteomics of thirty six individuals, 17 of which had confirmed IPF. Proteomics data was analyzed by volcano plot, hierarchical clustering, Partial-least square discriminant analysis (PLS-DA) and Ingenuity pathway analysis. Univariate and multivariate statistical analysis overlap identified haptoglobin-related protein as a possible marker of IPF when compared to control samples (Area under the curve 0.851, ROC-analysis). LXR/RXR activation and complement activation pathways were enriched in t-test significant proteins and oxidative regulators, complement proteins and protease inhibitors were enriched in PLS-DA significant proteins. Our pilot study points towards aberrations in complement activation and oxidative damage in IPF patients and provides haptoglobin-related protein as a new candidate biomarker of IPF.
Fluconazole resistance in Candida albicans is induced by Pseudomonas aeruginosa quorum sensing
Authors: Bandara H. M. H. N. , Wood D. L. A. , Vanwonterghem I. , Hugenholtz P. , Cheung B. P. K. , Samaranayake L. P.
Published: May 2020

Microorganisms employ quorum sensing (QS) mechanisms to communicate with each other within microbial ecosystems. Emerging evidence suggests that intraspecies and interspecies QS plays an important role in antimicrobial resistance in microbial communities. However, the relationship between interkingdom QS and antimicrobial resistance is largely unknown. Here, we demonstrate that interkingdom QS interactions between a bacterium, Pseudomonas aeruginosa and a yeast, Candida albicans, induce the resistance of the latter to a widely used antifungal fluconazole. Phenotypic, transcriptomic, and proteomic analyses reveal that P. aeruginosa’s main QS molecule, N-(3-Oxododecanoyl)-L-homoserine lactone, induces candidal resistance to fluconazole by reversing the antifungal’s effect on the ergosterol biosynthesis pathway. Accessory resistance mechanisms including upregulation of C. albicans drug-efflux, regulation of oxidative stress response, and maintenance of cell membrane integrity, further confirm this phenomenon. These findings demonstrate that P. aeruginosa QS molecules may confer protection to neighboring yeasts against azoles, in turn strengthening their co-existence in hostile polymicrobial infection sites.
Sero-epidemiological study of the rotavirus VP8* protein from different P genotypes in Valencia, Spain
Authors: Vila-Vicent Susana , Gozalbo-Rovira Roberto , Rubio-Del-Campo Antonio , Santiso-Bellón Cristina , Navarro-Lleó Noemí , Muñoz Carlos , Buesa Javier , Rodríguez-Díaz Jesús
Published: May 2020

The aims of the present work were to determine the prevalence and titer of serum antibodies against several rotavirus VP8* proteins from different P genotypes in children and adults in Valencia, Spain; and to determine the role of the secretor status (FUT2G428A polymorphism) in the antibody response. The VP8* protein from the P[4], P[6], P[8], P[9], P[11], P[14] and P[25] genotypes were produced in E. coli. These proteins were tested with 88 serum samples from children (n = 41, 3.5 years old in average) and from adults (n = 47, 58 years old in average) by ELISA. A subset of 55 samples were genotyped for the FUT2G428A polymorphism and the antibody titers compared. The same subset of samples was also analysed by ELISA using whole rotavirus Wa particles (G1P[8]) as antigen. Ninety-three per cent of the samples were positive for at least one of the VP8* antigens. Differences in the IgG seroprevalence were found between children and adults for the P[4], P[8] and P[11] genotypes. Similarly, significant differences were found between adults and children in their antibody titers against the P[4], P[8], and P[11] VP8* genotypes, having the children higher antibody titers than adults. Interestingly, positive samples against rare genotypes such as P[11] (only in children), P[14] and P[25] were found. While no statistical differences in the antibody titers between secretors and non-secretors were found for any of the tested P genotypes studied, a higher statistic significant prevalence for the P[25] genotype was found in secretors compared to non-secretors. Significant differences in the antibody titers between secretors and non-secretors were found when the whole viral particles from the Wa rotavirus strain (G1P[8]) were used as the antigen.
Direct exposure of the head to solar heat radiation impairs motor-cognitive performance
Authors: Piil Jacob F. , Christiansen Lasse , Morris Nathan B. , Mikkelsen C. Jacob , Ioannou Leonidas G. , Flouris Andreas D. , Lundbye-Jensen Jesper , Nybo Lars
Published: May 2020

Health and performance impairments provoked by thermal stress are societal challenges geographically spreading and intensifying with global warming. Yet, science may be underestimating the true impact, since no study has evaluated effects of sunlight exposure on human brain temperature and function. Accordingly, performance in cognitively dominated and combined motor-cognitive tasks and markers of rising brainstem temperature were evaluated during exposure to simulated sunlight (equal to ~1000 watt/m2). Acute exposure did not affect any performance measures, whereas prolonged exposure of the head and neck provoked an elevation of the core temperature by 1 °C and significant impairments of cognitively dominated and motor task performances. Importantly, impairments emerged at considerably lower hyperthermia levels compared to previous experiments and to the trials in the presents study without radiant heating of the head. These findings highlight the importance of including the effect of sunlight radiative heating of the head and neck in future scientific evaluations of environmental heat stress impacts and specific protection of the head to minimize detrimental effects.
Relative abundance of derelict fishing gear in the Hawaii-based pelagic longline fishery grounds as estimated from fishery observer data
Authors: Uhrin Amy V. , Walsh William A. , Brodziak Jon
Published: May 2020

Derelict fishing gear (DFG) is abundant across the remote North Pacific Ocean, accumulating in convergence zones that coincide with the fishing grounds of the Hawai’i-based pelagic longline fishery. Longlines are prone to snagging DFG, providing an opportunistic, yet regular, reporting mechanism by longline fishery observers (fishery-dependent data). We apply a zero-inflated negative binomial model previously used to standardize catch per unit effort (CPUE) for bycatch and incidentally caught species in this fishery to estimate DFG relative abundance and qualitative trends within the longline fishing grounds. During 2008–2016, observers reported 1326 marine debris items intercepted by longlines, dominated by DFG at nearly 90%. Modeling results suggest that the relative abundance of DFG has declined ~66% from 2008–2016. DFG standardized CPUE was higher for longlines fished inside the North Pacific Subtropical Convergence Zone (versus outside) and increased moving eastward and northward toward the Great Pacific Garbage Patch. Despite substantially less effort in the shallow-set sector of the fishery (∼60 m depth), DFG standardized CPUE was four-fold greater than that of the deep-set sector (∼250 m) suggesting that marine debris observer reporting focused in this sector may be most effective. Some fishermen voluntarily stow snagged debris; incentivizing at-sea removal may elicit further cooperation.
Longitudinal optical imaging technique to visualize progressive axonal damage after brain injury in mice reveals responses to different minocycline treatments
Authors: Pernici Chelsea D. , Rowe Rachel K. , Doughty P. Timothy , Madadi Mahboubeh , Lifshitz Jonathan , Murray Teresa A.
Published: May 2020

A high-resolution, three-dimensional, optical imaging technique for the murine brain was developed to identify the effects of different therapeutic windows for preclinical brain research. This technique tracks the same cells over several weeks. We conducted a pilot study of a promising drug to treat diffuse axonal injury (DAI) caused by traumatic brain injury, using two different therapeutic windows, as a means to demonstrate the utility of this novel longitudinal imaging technique. DAI causes immediate, sporadic axon damage followed by progressive secondary axon damage. We administered minocycline for three days commencing one hour after injury in one treatment group and beginning 72 hours after injury in another group to demonstrate the method’s ability to show how and when the therapeutic drug exerts protective and/or healing effects. Fewer varicosities developed in acutely treated mice while more varicosities resolved in mice with delayed treatment. For both treatments, the drug arrested development of new axonal damage by 30 days. In addition to evaluation of therapeutics for traumatic brain injury, this hybrid microlens imaging method should be useful to study other types of brain injury and neurodegeneration and cellular responses to treatment.
Enzymatic and genetic characterization of lignin depolymerization by Streptomyces sp. S6 isolated from a tropical environment
Authors: Riyadi Fatimah Azizah , Tahir Analhuda Abdullah , Yusof Nurtasbiyah , Sabri Nurul Syazwani Ahmad , Noor Megat Johari Megat Mohd , Akhir Fazrena Nadia M. D. , Othman Nor’azizi , Zakaria Zuriati , Hara Hirofumi
Published: May 2020

The conversion of lignocellulosic biomass into bioethanol or biochemical products requires a crucial pretreatment process to breakdown the recalcitrant lignin structure. This research focuses on the isolation and characterization of a lignin-degrading bacterial strain from a decaying oil palm empty fruit bunch (OPEFB). The isolated strain, identified as Streptomyces sp. S6, grew in a minimal medium with Kraft lignin (KL) as the sole carbon source. Several known ligninolytic enzyme assays were performed, and lignin peroxidase (LiP), laccase (Lac), dye-decolorizing peroxidase (DyP) and aryl-alcohol oxidase (AAO) activities were detected. A 55.3% reduction in the molecular weight (Mw) of KL was observed after 7 days of incubation with Streptomyces sp. S6 based on gel-permeation chromatography (GPC). Gas chromatography-mass spectrometry (GC-MS) also successfully highlighted the production of lignin-derived aromatic compounds, such as 3-methyl-butanoic acid, guaiacol derivatives, and 4,6-dimethyl-dodecane, after treatment of KL with strain S6. Finally, draft genome analysis of Streptomyces sp. S6 also revealed the presence of strong lignin degradation machinery and identified various candidate genes responsible for lignin depolymerization, as well as for the mineralization of the lower molecular weight compounds, confirming the lignin degradation capability of the bacterial strain.
Soy and Arabidopsis receptor-like kinases respond to polysaccharide signals from Spodoptera species and mediate herbivore resistance
Authors: Uemura Takuya , Hachisu Masakazu , Desaki Yoshitake , Ito Ayaka , Hoshino Ryosuke , Sano Yuka , Nozawa Akira , Mujiono Kadis , Galis Ivan , Yoshida Ayako , Nemoto Keiichirou , Miura Shigetoshi , Nishiyama Makoto , Nishiyama Chiharu , Horito Shigeomi , Sawasaki Tatsuya , Arimura Gen-ichiro
Published: May 2020

Plants respond to herbivory by perceiving herbivore danger signal(s) (HDS(s)), including “elicitors”, that are present in herbivores’ oral secretions (OS) and act to induce defense responses. However, little is known about HDS-specific molecules and intracellular signaling. Here we explored soybean receptor-like kinases (RLKs) as candidates that might mediate HDS-associated RLKs’ (HAKs’) actions in leaves in response to OS extracted from larvae of a generalist herbivore, Spodoptera litura. Fractionation of OS yielded Frα, which consisted of polysaccharides. The GmHAKs composed of their respective homomultimers scarcely interacted with Frα. Moreover, Arabidopsis HAK1 homomultimers interacted with cytoplasmic signaling molecule PBL27, resulting in herbivory resistance, in an ethylene-dependent manner. Altogether, our findings suggest that HAKs are herbivore-specific RLKs mediating HDS-transmitting, intracellular signaling through interaction with PBL27 and the subsequent ethylene signaling for plant defense responses in host plants.
Phase diagram of the two-dimensional Hubbard-Holstein model
Authors: Costa Natanael C. , Seki Kazuhiro , Yunoki Seiji , Sorella Sandro
Published: May 2020

The electron–electron and electron–phonon interactions play an important role in correlated materials, being key features for spin, charge and pair correlations. Thus, here we investigate their effects in strongly correlated systems by performing unbiased quantum Monte Carlo simulations in the square lattice Hubbard-Holstein model at half-filling. We study the competition and interplay between antiferromagnetism (AFM) and charge-density wave (CDW), establishing its very rich phase diagram. In the region between AFM and CDW phases, we have found an enhancement of superconducting pairing correlations, favouring (nonlocal) s-wave pairs. Our study sheds light over past inconsistencies in the literature, in particular the emergence of CDW in the pure Holstein model case.
Fragmentation of polymer nanocomposites: modulation by dry and wet weathering, fractionation, and nanomaterial filler
Authors: Zepp Richard , Ruggiero Emmanuel , Acrey Brad , Davis Mary J. B. , Han Changseok , Hsieh Hsin-Se , Vilsmeier Klaus , Wohlleben Wendel , Sahle-Demessie Endalkachew
Published: May 2020

Weathering and fragmentation of polymer nanocomposites.
Monitoring protein ubiquitination and SUMOylation in real-time by NMR
Authors: Habibullah Batul Ismail , Tripathi Vasvi , Surana Parag , Das Ranabir
Published: May 2020

A new tag-free method detects ubiquitination and SUMOylation of proteins in real time by NMR under physiological conditions.
Platinum complexes of a boron-rich diphosphine ligand
Authors: Drover Marcus W. , Bowes Eric G. , Dufour Maeve C. , Lesperance-Nantau Lindsay A.
Published: May 2020

Herein, we describe the preparation, characterization, and reactivity of two PtII bis-hydrocarbyl complexes containing the 1,2-bis(di(3-dicyclohexylboraneyl)propylphosphino)ethane (P2BCy4) ligand.
Liquid–liquid–liquid three-phase microsystem: hybrid slug flow–laminar flow
Authors: Wang Tao , Xu Cong
Published: May 2020

Hybrid slug flow–laminar flow: spontaneous aqueous–organic–aqueous three-phase mass transfer with easy phase separation and chaotic advection.
Unexpectedly high stability and surface reconstruction of PdAuAg nanoparticles for formate oxidation electrocatalysis
Authors: Pan Bowei , Chen Fuyi , Kou Bo , Wang Junpeng , Tang Quan , Guo Longfei , Wang Qiao , Li Zhen , Bian Weiqi , Wang Jiali
Published: May 2020

Pd3Au3Ag1 NPs on carbon nanotubes undergo a potential-driven surface reconstruction that improves the activity and durability for the electrocatalytic formate oxidation reaction.
An ultrathin two-dimensional vertical ferroelectric tunneling junction based on CuInP2S6 monolayer
Authors: Zhao Min , Gou Gaoyang , Ding Xiangdong , Sun Jun
Published: May 2020

A 1 nm-thick 2D vertical ferroelectric tunneling junction composed of a van der Waals stacked graphene/CuInP2S6 monolayer/graphene heterostructure.
A topological semimetal Li2CrN2 sheet as a promising hydrogen storage material
Authors: Ma Li-Juan , Sun Qiang
Published: May 2020

The hydrogen storage performance of topological quantum materials is explored for the first time.
A MnV2O6/graphene nanocomposite as an efficient electrocatalyst for the oxygen evolution reaction
Authors: Kim Kyeong-Ho , Choi Yun-Hyuk , Hong Seong-Hyeon
Published: May 2020

A MnV2O6/graphene nanocomposite is a promising candidate as an OER electrocatalyst for water splitting with superior performance and cost-effectiveness.
Modulation engineering of in situ cathodic activation of FePx based on W-incorporation for the hydrogen evolution reaction
Authors: Yang Min , Zhu Yu-Ran , Lin Zhong-Yuan , Yan Xin-Tong , Dong Bin , Zhou Ya-Nan , Li Qing-Zhong , Zhou Yu-Lu , Nan Jun , Chai Yong-Ming
Published: May 2020

In situ electrochemical activation as a new pretreating method to adjust electrocatalytic performance attracts extensive attention.
Synthesis of monodisperse water-stable surface Pb-rich CsPbCl3 nanocrystals for efficient photocatalytic CO2 reduction
Authors: Zhu Jingrun , Zhu Yihua , Huang Jianfei , Hou Lu , Shen Jianhua , Li Chunzhong
Published: May 2020

Monodisperse water-stable surface Pb-rich lead halide perovskite nanocrystals (NCs) were obtained by the liquid–solid interpenetration method. The maximum CO2 photoreduction rate of the obtained NCs is as high as 169.37 μmol g−1 h−1.
Ring-opening copolymerization of cyclic epoxide and anhydride using a five-coordinate chromium complex with a sterically demanding amino triphenolate ligand
Authors: Ryu Ho Kyun , Bae Dae Young , Lim Hyeongi , Lee Eunsung , Son Kyung-sun
Published: May 2020

This work describes polyester synthesis via alternating ring-opening copolymerization of epoxides and anhydrides using a trigonal bipyramidal chromium complex containing a sterically demanding ligand.
Catalyst-controlled formal [4 + 1] annulation of N-vinyl fluorenone nitrones and allenoates to prepare spirofluorenylpyrrolines
Authors: Wei Cui , Zhang Jin-Qi , Zhang Jia-Jie , Liang Cui , Mo Dong-Liang
Published: May 2020

A simple gimeracil-controlled formal [4 + 1] annulation was developed to prepare various spirofluorenylpyrrolines in good yields with high diastereoselectivity from N-vinyl fluorenone nitrones and allenoates.
Nanoporous materials with predicted zeolite topologies
Authors: Blatov Vladislav A. , Blatova Olga A. , Daeyaert Frits , Deem Michael W.
Published: May 2020

Topological exploration of crystal structures demonstrates the presence of known zeolites, inorganics, and MOFs in a database of predicted materials.
Lanthanide-based inorganic–organic hybrid materials for photon-upconversion
Authors: Safdar Muhammad , Ghazy Amr , Lastusaari Mika , Karppinen Maarit
Published: May 2020

Photon-upconversion materials are capable of converting low energy infrared light into higher energy visible or ultraviolet light.
Incentive framework for mobile data offloading market under QoE‐aware users
Authors: Song Xin , Qin Lei , Qi Haoyang , Li Suyuan , Qian Haijun , Dong Li , Ni Yue
Published: May 2020

Mobile data offloading enables the mobile network operator (MNO) to deal with the explosive growth of cellular data by leasing third‐party access points (APs) to partially deliver the mobile traffic. This study proposes a novel incentive framework for the mobile data offloading market under QoE‐aware users. Considering user satisfaction, the authors formulate the interaction among the MNO, APs, and offloaded users as a three‐stage Stackelberg game. Through the Stackelberg game, the APs determine their optimal contributions via the best response method and the offloaded users determine their optimal accepted prices via the proposed dynamic pricing mechanism. Then the MNO makes its decision for profit maximisation. Furthermore, based on contract theory, an optimal dynamic scheme between the MNO and the remaining users is established. Under the dynamic scheme, they prove the personal rationality and incentive compatibility properties. Moreover, the optimisation contract problem is transformed into a relaxed contract problem, and the proposed dynamic algorithm is subsequently used to handle non‐feasible solutions. Thus, the proposed framework can improve user satisfaction without affecting MNO profits. Simulation results show that the proposed framework can achieve better performances in terms of user satisfaction and MNO profits compared with traditional algorithms.
Approximate expressions for BER performance in downlink mmWave MU‐MIMO hybrid systems with different data detection approaches
Authors: Ortega Alvaro Javier , Sampaio‐Neto Raimundo , David Rodrigo Pereira
Published: May 2020

Millimetre‐wave (mmWave) communications have been regarded as a key technology for the next‐generation cellular systems since the huge available bandwidth can potentially provide the rates of multiple gigabits per second. Conventional precoding and combining techniques are impractical at mmWave scenarios due to manufacturing costs and power consumption. Hybrid alternatives have been considered as a promising technology to provide a compromise between hardware complexity and system performance. This study examines, using a semi‐analytic approach, the downlink performance of massive MU‐MIMO mmWave systems in terms of the bit error rate (BER). Also, a general expression is derived to estimate an upper bound/approximation to the BER performance via the Monte Carlo method, which can be used for any hybrid precoder/combiner, modulation and different data detectors. Numerical results evidence that the approximate BER expressions provide values very close to the ones obtained through simulation using only two statistical moments related to parameters of the system, mean and variance.
Analysis of optimal performance of MIMO networked control systems with encoding and packet dropout constraints
Authors: Hu Jun‐Wei , Zhan Xi‐Sheng , Wu Jie , Yan Huai‐Cheng
Published: May 2020

In this study, optimal performance of the multi‐input multi‐output networked control systems (NCSs) is analysed. The systems are with a time‐delay and channel noise constraints in the forward network channel, and encoding–decoding and quantisation constraints, and packet dropouts in the feedback network channel. By using the Youla parameterisation of a two‐degree‐of‐freedom controller, a new and explicit expression of the optimal performance is derived. The optimal performance is obtained using the method of norm technique. The results show that the positions and directions of the non‐minimum phase zeros and unstable poles of a given plant are related to the optimal tracking error. On the other hand, the optimal tracking error is dependent on channel noise, quantisation noise, encoding–decoding, time‐delay, packet dropout probability and other correction factors. Finally, simulation results demonstrate the effectiveness of the proposed control scheme.
Composite anti‐disturbance control for semi‐Markovian jump systems with time‐varying delay and generally uncertain transition rates via disturbance observer
Authors: Xu Tianbo , Gao Xianwen , Pang Guochen , Qi Wenhai , Kao Yonggui
Published: May 2020

The problem of composite anti‐disturbance control for semi‐Markovian jump systems (S‐MJSs) with time‐varying delay via disturbance observer is analysed in this study. Unlike the existing methods, generally uncertain transition rates, time‐varying delay, multiple disturbances, the performance and disturbance‐observer‐based control (DOBC) are all considered in S‐MJSs. The method which combines DOBC and control is used to guarantee the system performance level of time‐varying delay S‐MJSs. Firstly, a sufficient condition of stochastic stability in the performance level for the composite control system is given by using piecewise Lyapunov–Krasovskii functional. Secondly, the optimal value of disturbance suppression level for the system is solved by an optimisation algorithm. Thirdly, variation interval of time‐delay has been divided into equal small intervals for reducing the conservatism of the method which addresses the mode‐dependent time‐delay problem. Furthermore, the composite controller and disturbance observer which satisfy the proposed stability condition are designed to address the composite anti‐disturbance control problem of the closed‐loop system. Finally, two practical systems are provided to testify the accuracy of research methods.
Performance analysis and temperature field study of IPMSM for electric vehicles based on winding transformation strategy
Authors: Xu Xuefeng , Zhang Guoqiang , Li Guangkuo , Zhang Bingyi
Published: May 2020

Recently, the high‐performance and high‐reliability permanent‐magnet synchronous machine (PMSM) has attached intensive attention due to development of electric vehicles (EVs). In this study, in order to improve the capability of output torque, an improved method of interior PMSM (IPMSM) for EV based on winding transformation (WT) strategy is proposed. In the proposed method, the power electronics technology, the vector control algorithm, and the multiple‐field analysis including electromagnetic field, fluid field, and temperature field are combined. Therefore, the steady‐state and dynamic performances of WT‐IPMSM are analysed comprehensively. The accuracy of the temperature field calculation is improved by the electromagnetic–thermal iterative method. Meanwhile, the influence of pulse‐width modulation time harmonics caused by inverter on the eddy current loss of PMs and related laws is summarised. Finally, the effectiveness and feasibility of the proposed method is verified by the prototype test.
Investigation of rotor strength and rotor dynamics for high‐speed high‐power switched reluctance machines
Authors: Gan Chun , Chen Yu , Cui Xiupeng , Sun Jianbo , Ni Kai , Qu Ronghai
Published: May 2020

This study proposes an investigation scheme of the rotor strength and rotor dynamic characteristics for high‐speed high‐power switched reluctance machines (SRMs). The analytical model and finite element analysis model are established to predict the maximum stress and deformation in the rotor. The Mises yield criterion is employed to verify the strength of the rotor at 1.2 times the rated speed. For the rotor dynamics, critical speed, unbalance response, and stability of the shaft system are analysed in detail. In the developed critical speed calculation scheme, the gyroscopic effect and the impact of the rotation speed on the stiffness and damping are considered. Then, the critical speeds acquired by the developed scheme are compared with those derived by using the conventional method. The unbalance response curves at different nodes are adopted for the unbalance response calculation, while the stability of the shaft system is verified by calculating the logarithmic decrement rates. The critical speed measurement experiment is performed on a 160 kW and 18,000 r/min SRM prototype, and the proposed critical speed calculation scheme is proved to be effective and accurate. The effectiveness of the unbalance response calculation method and the stability judgement technique are also verified by experiment.
Parameter identification and modelling of photovoltaic power generation systems based on LVRT tests
Authors: Jia Jiaoxin , Yan Xiangwu , Wang Yuke , Aslam Waseem , Liu Wenzhuo
Published: May 2020

With the increasing usage of photovoltaic (PV) generation systems, it is of great relevance to develop effective models to characterise the dynamic behaviours of actual PV systems under different failures and operation modes. In general, three test items are required to identify the three types of parameters, namely, the low‐voltage ride‐through (LVRT) control parameters, PV array parameters, and DC voltage loop parameters. To simplify the test items and steps needed for parameter identification, an appropriate identification and modelling method for a PV generation system is proposed on the basis of an LVRT test. This LVRT field test is conducted on a large PV system in North China. The three groups of parameters are identified with the test data. Specifically, the equivalent resistance of the collection line of a PV array is considered to accurately simulate the dynamic process of DC voltage. Lastly, the effectiveness of the proposed method is verified through a comparison of simulation results and field test results.
Quantitative analysis of cell morphology based on the contourlet transform
Authors: Huang Yali , Hu Xuefang , Hao Lei , Gao Yuehua , Liu Zhiwen , Wang Peiguang
Published: May 2020

Cellular morphology analysis has been widely used to detect abnormalities in biological processes. Clinicians have observed that lymphocytes become highly deformable under special conditions, particularly when graft rejection occurs. The characterisation of lymphocyte boundary deformation provides important quantitative parameters to assist clinical rejection diagnosis. To evaluate the dynamic features of the boundaries of target lymphocyte when a graft rejection occurs, a contourlet transform‐based method is proposed to extract the characteristics of cell boundary variation. First, the lymphocyte is segmented and tracked to obtain their edge‐to‐centroid distance signals. Subsequently, a contourlet transform is performed on these signals, during which the edge‐to‐centroid distance signals of the lymphocyte is decomposed at multiple scales using the Laplacian pyramid; a multi‐directional decomposition is then performed using a direction filter to merge the singularities distributed along the same direction and obtain the contourlet transform coefficients. Finally, statistical parameters of the cell dynamic boundaries are calculated, then fed into the support vector machine for classification of the cell deformation. Our findings demonstrate that contourlet transform has better performance in representing image features such as cell boundaries than wavelet transform for its prosperities of multi‐scale and multi‐directional decomposition for cell images.
Seed picking crossover optimisation algorithm for semantic segmentation from images
Authors: Arunkumar Manonmani , Pushparaj Vijayakumari
Published: May 2020

Semantic image segmentation treats the issues involved in the object recognition and image segmentation as a combined task. The chief notion of semantic segmentation is to partition the image into visually uniform regions and to discriminate the class of the partitioned regions. Pixel classification is done over the segmented regions by assigning semantic labels. In general, inference frameworks are fed with the combination of low‐level features and high‐level contextual cues to segment an image. Since these combinations are rarely object consistent, result with minimum classification accuracy because of choosing non‐influencing features and cues to track specific objects. To overcome this problem, a nature‐inspired meta‐heuristic optimization algorithm called Seed Picking Crossover Optimization (SPCO) is proposed to optimize i.e. train the CRF (Conditional Random Field) for choosing relevant feature to segment the object with high accuracy. To meritoriously recognize the objects, a semi‐segmentation process is initially performed using Simple Linear Iterative Clustering (SLIC) algorithm. For pixel transformation and pixel association, Dirichlet process mixture model and CRF are employed. Optimized CRFs are used where the parametric optimization is done using the proposed SPCO algorithm. The proposed work results with 84% on classification accuracy and the performance evaluations are done using MSRC‐21 dataset.
Unified deep learning approach for prediction of Parkinson's disease
Authors: Wingate James , Kollia Ilianna , Bidaut Luc , Kollias Stefanos
Published: May 2020

The study presents a novel approach, based on deep learning, for diagnosis of Parkinson's disease through medical imaging. The approach includes analysis and use of the knowledge extracted by deep convolutional and recurrent neural networks when trained with medical images, such as magnetic resonance images and dopamine transporters scans. Internal representations of the trained DNNs constitute the extracted knowledge which is used in a transfer learning and domain adaptation manner, so as to create a unified framework for prediction of Parkinson's across different medical environments. A large experimental study is presented illustrating the ability of the proposed approach to effectively predict Parkinson's, using different medical image sets from real environments.
Underwater sonar image classification using generative adversarial network and convolutional neural network
Authors: Xu Yichao , Wang Xingmei , Wang Kunhua , Shi Jiahao , Sun Wei
Published: May 2020

This study presents a generative adversarial network (GAN) called conditional Wasserstein GAN‐gradient penalty (CWGAN‐GP)&DenseNet and ResNet, and a convolutional neural network (CNN) called improved CNN to complete underwater sonar image classification. Specifically, to solve the problem of insufficient underwater sonar image data, the CWGAN‐GP&DR is developed to expand underwater sonar image data set. Besides, to improve the analysis and utilisation of the feature map and reduce the misclassification rate of categories with similar probabilities, improved CNN is proposed to complete the final underwater sonar image classification. Finally, compared with other methods, the CWGAN‐GP&DR generate better underwater sonar images and effectively expand the underwater sonar image data set. Moreover, compared with the original data set and other expanded data set, the highest accuracy rate of 85.00% can be obtained on the CWGAN‐GP&DR expanded data set by CNN. Furthermore, CNN, CNN‐bais and improved CNN are used to perform classification experiments on each data set, and the accuracy of the improved CNN is the highest on all data sets and reached the highest accuracy of 87.71% on CWGAN‐GP&DR expanded data set. The experimental results demonstrate that the proposed method can effectively improve the performance of underwater sonar image classification.
Sectorised base stations for FSO ground‐to‐train communications
Authors: Mohan Nithin , Abadi Mojtaba Mansour , Ghassemlooy Zabih , Zvanovec Stanislav , Hudson Ralph , Bhatnagar Manav R.
Published: May 2020

Evolution and accessibility of smart‐phones have led to a huge demand in network bandwidth. The ubiquitous use of smart‐phones in high‐speed trains poses a unique challenge in delivering high‐speed internet service on board. This challenge can be overcome by employing free‐space optics, an alternative to radio‐frequency technology. Previous coverage models for ground–train communications employed single laser systems with a larger divergence angle to cover a larger distance. Larger divergence angles lead to larger geometric losses, which may result in a non‐reliable communication link. This study proposes a sectorised multi‐beam coverage model with a smaller divergence angle to reduce the impact of geometric losses in the system. This study also proposes two receiver (Rx) architectures for Rxs deployed on the train. Along with geometric losses, the atmospheric attenuation is taken into consideration for the FSO link. The performance of the ground–train communications system in terms of bit‐error‐rate is evaluated under weak turbulence conditions via numerical simulation.
Adaptive repetitive controller for an active power filter in three‐ phase four‐ wire systems
Authors: Santiprapan Phonsit , Booranawong Apidet , Areerak Kongpol , Saito Hiroshi
Published: May 2020

Load changing behaviour significantly affects the compensating current control performance of active power filters (APFs). Owing to this effect, harmonic currents at the source can significantly degrade the power quality of the system. This work proposes an adaptive repetitive controller based on a fuzzy logic algorithm to improve current control performance. In addition, a new design approach to fuzzy membership functions is also proposed. The design concept for the adaptive repetitive controller follows a stability analysis of the compensating current control and a mathematical model of the APF. In experimental testing, a power system was implemented with the proposed controller using the processor‐ in‐ the‐ loop technique on an eZdsp™ F28335 board and the MATLAB/ Simulink programme. The experimental results indicated that the proposed adaptive repetitive controller would provide better harmonic current‐tracking performance compared with conventional repetitive controllers. Also, the APF used in conjunction with the proposed controller would efficiently mitigate harmonic currents even where non‐linear loads changed. Moreover, the percentage of total harmonic distortion would be maintained within the IEEE standard 519–2014.
High‐dimensional sparse recovery using modified generalised SL0 and its application in 3D ISAR imaging
Authors: Nazari Milad , Mehrpooya Ali , Bastani Muhammad Hassan , Nayebi Mehdi , Abbasi Zahra
Published: May 2020

Sparse representation can be extended to high dimensions and can be used in many applications, including three‐dimensional (3D) Inverse synthetic aperture radar (ISAR) imaging. In this study, the high‐dimensional sparse representation problem and a recovery method called high‐dimensional smoothed least zero‐norm (HDSL0) are formulated. In this method, the theory and computation of tensors and approximating L0 norm using Gaussian functions are used for sparse recovery of high‐dimensional data. To enhance the performance of HDSL0, modified regularised high‐dimensional SL0 (MRe‐HDSL0) algorithm, which benefits from the regularised form of SL0 and an additional hard thresholding step, is proposed. According to the numerical simulations, the recovery signal to noise ratio for MRe‐HDSL0 compared to HDSL0, under the same experimental conditions, is 10, 9, and 8 dB higher in 1D, 2D, and 3D cases, respectively. The proposed algorithm also maintains the benefits of high speed and low computational cost of SL0. Besides, the formulation of compressed sensing‐based 3D ISAR imaging is expressed. Finally, the proposed algorithm is applied to reconstruct 3D ISAR images of two synthetic targets, which are created based on the scattering point model. Based on the achieved results, the quality of reconstructed images using MRe‐HDSL0 is better than other simulated methods.
Comparison of radar signatures based on flight morphology for large birds and small birds
Authors: Gong Jiangkun , Yan Jun , Li Deren , Chen Ruizhi
Published: May 2020

The identification of bird size from radar echoes is a mission in radar ornithology. Yet, neither radar cross‐section nor wingbeat frequency measured from radar signals of birds is good recognition discriminant. In this study, the authors propose that large birds habitually carry their feet stretched out behind them during flight, leaving their feet apart from the body and being recognisable to both human observation and radar detection, while small birds tend to carry their feet drawn up in front, clinging to the body, thus hiding their feet from detection. The 23 most common bird species groups involved in bird strike hazards are consistent with this classification criterion. The visibility of a bird's feet will register radar signatures on bird echoes, and these signatures contribute to the classification of radar echoes from different sized birds in relatively short data sampling time. Their Ku‐band avian radar data indicated that those radar signatures, including distribution of scattering centres and the modulation in radar echoes from small birds and large birds, do differ in radar echoes from large birds and small birds.
A Lyαnebula atz ∼ 3.3
Authors: Hibon P. , Tang F. , Thomas R.
Published: May 2020

Context.Searching for high-redshift galaxies is a field of intense activity in modern observational cosmology that will continue to grow with future ground-based and sky observatories. Over the last few years, a lot has been learned about the high-zUniverse.

Aims.Despite extensive Lyαblobs (LAB) surveys from low to high redshifts, giant LABs over 100 kpc have been found mostly atz ∼ 2–4. This redshift range is coincident with the transition epoch of galactic gas-circulation processes from inflows to outflows atz ∼ 2.5–3. This suggests that the formation of giant LABs may be related to a combination of gas inflows and outflows. Their extreme youth makes them interesting objects in the study of galaxy formation as they provide insight into some of the youngest known highly star forming galaxies, with only modest time investments using ground-based telescopes.

Methods.Systematic narrow-band Lyαnebula surveys are ongoing, but they are limited in their covered redshift range and their comoving volume. This poses a significant problem when searching for such rare sources. To address this problem, we developed a systematic searching tool, ATACAMA (A Tool for seArChing for lArge LyMan Alpha nebulae) designed to find large Lyαnebulae at any redshift within deep multi-wavelength broad-band imaging.

Results.We identified a Lyαnebula candidate atzphot ∼ 3.3 covering an isophotal area of 29.4arcsec2. Its morphology shows a bright core and a faint core which coincides with the morphology of previously known Lyαblobs. A first estimation of the Lyαequivalent width and line flux agree with the values from the study led by several groups.
The nature of the companion in the Wolf-Rayet system EZ Canis Majoris
Authors: Koenigsberger G. , Schmutz W.
Published: May 2020

Context. EZ Canis Majoris is a classical Wolf-Rayet star whose binary nature has been debated for decades. It was recently modeled as an eccentric binary with a periodic brightening at periastron of the emission originating in a shock heated zone near the companion.

Aims. The focus of this paper is to further test the binary model and to constrain the nature of the unseen close companion by searching for emission arising in the shock-heated region.

Methods. We analyze over 400 high resolution International Ultraviolet Explorer spectra obtained between 1983 and 1995 and XMM-Newton observations obtained in 2010. The light curve and radial velocity (RV) variations were fit with the eccentric binary model and the orbital elements were constrained.

Results. We find RV variations in the primary emission lines with a semi-amplitude K1 ∼ 30 km s−1 in 1992 and 1995, and a second set of emissions with an anti-phase RV curve with K2 ∼ 150 km s−1. The simultaneous model fit to the RVs and the light curve yields the orbital elements for each epoch. Adopting a Wolf-Rayet mass M1 ∼ 20 M⊙ leads to M2 ∼ 3−5 M⊙, which implies that the companion could be a late B-type star. The eccentric (e = 0.1) binary model also explains the hard X-ray light curve obtained by XMM-Newton and the fit to these data indicates that the duration of maximum is shorter than the typical exposure times.

Conclusions: The anti-phase RV variations of two emission components and the simultaneous fit to the RVs and the light curve are concrete evidence in favor of the binary nature of EZ Canis Majoris. The assumption that the emission from the shock-heated region closely traces the orbit of the companion is less certain, although it is feasible because the companion is significantly heated by the WR radiation field and impacted by the WR wind.