bluuebunny/crossref_metadata_2025 huggingface dataset:
Screening of metabolic modulators identifies new strategies to target metabolic reprogramming in melanoma
Authors: Abildgaard Cecilie , Rizza Salvatore , Christiansen Helle , Schmidt Steffen , Dahl Christina , Abdul-Al Ahmad , Christensen Annette , Filomeni Giuseppe , Guldberg Per
Published: February 2021

The prognosis of metastatic melanoma remains poor due to de novo or acquired resistance to immune and targeted therapies. Previous studies have shown that melanoma cells have perturbed metabolism and that cellular metabolic pathways represent potential therapeutic targets. To support the discovery of new drug candidates for melanoma, we examined 180 metabolic modulators, including phytochemicals and anti-diabetic compounds, for their growth-inhibitory activities against melanoma cells, alone and in combination with the BRAF inhibitor vemurafenib. Two positive hits from this screen, 4-methylumbelliferone (4-MU) and ursolic acid (UA), were subjected to validation and further characterization. Metabolic analysis showed that 4-MU affected cellular metabolism through inhibition of glycolysis and enhanced the effect of vemurafenib to reduce the growth of melanoma cells. In contrast, UA reduced mitochondrial respiration, accompanied by an increase in the glycolytic rate. This metabolic switch potentiated the growth-inhibitory effect of the pyruvate dehydrogenase kinase inhibitor dichloroacetate. Both drug combinations led to increased production of reactive oxygen species, suggesting the involvement of oxidative stress in the cellular response. These results support the potential use of metabolic modulators for combination therapies in cancer and may encourage preclinical validation and clinical testing of such treatment strategies in patients with metastatic melanoma.
A streamlined clinical metagenomic sequencing protocol for rapid pathogen identification
Authors: Jia Xiaofang , Hu Lvyin , Wu Min , Ling Yun , Wang Wei , Lu Hongzhou , Yuan Zhenghong , Yi Zhigang , Zhang Xiaonan
Published: February 2021

Metagenomic next-generation sequencing (mNGS) holds promise as a diagnostic tool for unbiased pathogen identification and precision medicine. However, its medical utility depends largely on assay simplicity and reproducibility. In the current study, we aimed to develop a streamlined Illumina and Oxford Nanopore-based DNA/RNA library preparation protocol and rapid data analysis pipeline. The Illumina sequencing-based mNGS method was first developed and evaluated using a set of samples with known aetiology. Its sensitivity for RNA viruses (influenza A, H1N1) was < 6.4 × 102 EID50/mL, and a good correlation between viral loads and mapped reads was observed. Then, the rapid turnaround time of Nanopore sequencing was tested by sequencing influenza A virus and adenoviruses. Furthermore, 11 respiratory swabs or sputum samples pre-tested for a panel of pathogens were analysed, and the pathogens identified by Illumina sequencing showed 81.8% concordance with qPCR results. Additional sequencing of cerebrospinal fluid (CSF) samples from HIV-1-positive patients with meningitis/encephalitis detected HIV-1 RNA and Toxoplasma gondii sequences. In conclusion, we have developed a simplified protocol that realizes efficient metagenomic sequencing of a variety of clinical samples and pathogen identification in a clinically meaningful time frame.
EXACT: a collaboration toolset for algorithm-aided annotation of images with annotation version control
Authors: Marzahl Christian , Aubreville Marc , Bertram Christof A. , Maier Jennifer , Bergler Christian , Kröger Christine , Voigt Jörn , Breininger Katharina , Klopfleisch Robert , Maier Andreas
Published: February 2021

In many research areas, scientific progress is accelerated by multidisciplinary access to image data and their interdisciplinary annotation. However, keeping track of these annotations to ensure a high-quality multi-purpose data set is a challenging and labour intensive task. We developed the open-source online platform EXACT (EXpert Algorithm Collaboration Tool) that enables the collaborative interdisciplinary analysis of images from different domains online and offline. EXACT supports multi-gigapixel medical whole slide images as well as image series with thousands of images. The software utilises a flexible plugin system that can be adapted to diverse applications such as counting mitotic figures with a screening mode, finding false annotations on a novel validation view, or using the latest deep learning image analysis technologies. This is combined with a version control system which makes it possible to keep track of changes in the data sets and, for example, to link the results of deep learning experiments to specific data set versions. EXACT is freely available and has already been successfully applied to a broad range of annotation tasks, including highly diverse applications like deep learning supported cytology scoring, interdisciplinary multi-centre whole slide image tumour annotation, and highly specialised whale sound spectroscopy clustering.
Quantifying cell death induced by doxorubicin, hyperthermia or HIFU ablation with flow cytometry
Authors: Lyon Paul Christopher , Suomi Visa , Jakeman Philip , Campo Leticia , Coussios Constantin , Carlisle Robert
Published: February 2021

Triggered release and targeted drug delivery of potent anti-cancer agents using hyperthermia-mediated focused-ultrasound (FUS) is gaining momentum in the clinical setting. In early phase studies, tissue biopsy samples may be harvested to assess drug delivery efficacy and demonstrate lack of instantaneous cell death due to FUS exposure. We present an optimised tissue cell recovery method and a cell viability assay, compatible with intra-cellular doxorubicin. Flow cytometry was used to determine levels of cell death with suspensions comprised of: (i) HT29 cell line exposed to hyperthermia (30 min at 47 °C) and/or doxorubicin, or ex-vivo bovine liver tissue exposed to (ii) hyperthermia (up to 2 h at 45 °C), or (iii) ablative high intensity FUS (HIFU). Flow cytometric analysis revealed maximal cell death in HT29 receiving both heat and doxorubicin insults and increases in both cell granularity (p < 0.01) and cell death (p < 0.01) in cells recovered from ex-vivo liver tissue exposed to hyperthermia and high pressures of HIFU (8.2 MPa peak-to-peak free-field at 1 MHz) relative to controls. Ex-vivo results were validated with microscopy using pan-cytokeratin stain. This rapid, sensitive and highly quantitative cell-viability method is applicable to the small masses of liver tissue typically recovered from a standard core biopsy (5–20 mg) and may be applied to tissues of other histological origins including immunostaining.
Using protein turnover to expand the applications of transcriptomics
Authors: Smail Marissa A. , Reigle James K. , McCullumsmith Robert E.
Published: February 2021

RNA expression and protein abundance are often at odds when measured in parallel, raising questions about the functional implications of transcriptomics data. Here, we present the concept of persistence, which attempts to address this challenge by combining protein half-life data with RNA expression into a single metric that approximates protein abundance. The longer a protein’s half-life, the more influence it can have on its surroundings. This data offers a valuable opportunity to gain deeper insight into the functional meaning of transcriptome changes. We demonstrate the application of persistence using schizophrenia (SCZ) datasets, where it greatly improved our ability to predict protein abundance from RNA expression. Furthermore, this approach successfully identified persistent genes and pathways known to have impactful changes in SCZ. These results suggest that persistence is a valuable metric for improving the functional insight offered by transcriptomics data, and extended application of this concept could advance numerous research fields.
Factors associated with fear of childbirth among Polish pregnant women
Authors: Ilska Michalina , Brandt-Salmeri Anna , Kołodziej-Zaleska Anna , Banaś Ewa , Gelner Hanna , Cnota Wojciech
Published: February 2021

The purpose of our study was to elucidate the association between obstetric and psychological factors and fear of childbirth (FOC) during the third trimester of pregnancy and to identify women at risk of severe FOC in Poland. An additional goal of the study was to verify the Polish version of the Wijma Delivery Expectancy Questionnaire (W-DEQ) and to establish its psychometric characteristics. Cross-sectional study with a total of 359 women recruited during routine visits to an antenatal clinic in Poland during the third trimester (≥ 27 weeks gestation). The survey included obstetric details (parity, obstetric history and preferred mode of delivery), and standardized psychological measures: the W-DEQ (fear of childbirth) and the EPDS (depressive symptoms). We demonstrated the satisfactory psychometric properties of the Polish version of the W-DEQ. Our findings confirm the one-factor structure found by the authors of the original version of the scale. A greater FOC was reported by women with unplanned pregnancies, women whose preferred mode of delivery was a cesarean section, and women who had previously undergone psychiatric treatment. The risk factors for severe FOC were depression, unplanned pregnancy or parity, and disagreement with the birth plan proposed by the obstetrician. The W-DEQ is a widely used, valid instrument for the assessment of FOC in pregnant women and can be used in Poland. Findings support the key role of obstetric and psychological variables in predicting fear of childbirth.
Pterostilbene inhibits gallbladder cancer progression by suppressing the PI3K/Akt pathway
Authors: Tong Chenhao , Wang Yali , Li Jiandong , Cen Wenda , Zhang Weiguang , Zhu Zhiyang , Yu Jianhua , Lu Baochun
Published: February 2021

Gallbladder cancer is the most common malignant tumor of the biliary system and is characterized by difficulty to diagnose in early stages, a high degree of malignancy, and poor prognosis. Finding new drugs may improve the prognosis for this dismal cancer. Herein, we investigated the potential application of pterostilbene (PTS) against gallbladder cancer in vivo and in vitro. PTS potently inhibited cell proliferation, migration and invasion of gallbladder cancer cells. Moreover, PTS also had a function of inducing apoptosis in vitro. Meanwhile, PTS reversed EMT with a correlated inhibition of PI3K/Akt activation. Tumor xenograft models showed that PTS inhibited tumor growth and had low toxicity in vivo, which were consistent with the in vitro data. These findings indicate that PTS arrests cell growth through inhibition of PI3K/AKT signaling and is a potential drug for the therapy of gallbladder cancer.
Anterior distal tibial plafond-plasty for the treatment of posttraumatic ankle osteoarthritis with anterior translation of the talus
Authors: Li Xingchen , Xu Yang , Guo Changjun , Yang Chonglin , Zhu Yuan , Xu Xiangyang
Published: February 2021

Posttraumatic ankle osteoarthritis (OA) represents a significant challenge to orthopedic surgeons, especially in cases of anterior talar translation and concomitant impaction of the anterior distal tibial plafond. The aim of this study was to evaluate the clinical outcomes of an intra-articular osteotomy for the management of these patients. A total of 21 patients meeting our criteria were retrospectively reviewed. Sixteen patients sustained initial pilon fractures, while five patients had Weber type C ankle fractures. Anterior distal tibial plafond-plasty was performed to address the impaction and anterior translation of the talus. The American Orthopedic Foot and Ankle Society (AOFAS) hindfoot score and visual analog scale (VAS) score were utilized as clinical outcomes. The lateral talar station (LTS), tibial lateral surface (TLS) angle, tibial anterior surface angle and talocrural angle were evaluated pre- and postoperatively. The modified Kellgren-Lawrence score was used for the evaluation of sagittal ankle OA. The average age at surgery was 35 years, and the average follow-up duration was 34 months. The AOFAS hindfoot score increased from 26 to 71 (p < 0.01), and the VAS score improved from 7 to 2 (p < 0.01). The LTS improved from 9.0 to 2.3 mm (p < 0.01), and the TLS angle improved from 72° to 81° (p < 0.01). Of the 21 patients, 18 showed improvement in or no worsening of ankle OA on the sagittal plane, while 3 developed advanced ankle OA. A congruent ankle joint on the sagittal plane could be achieved by anterior distal tibial plafond-plasty. This is a valuable treatment option for the salvage of posttraumatic ankle OA with anterior translation of the talus.
Clinical correlates of anti-SARS-CoV-2 antibody profiles in Spanish COVID-19 patients from a high incidence region
Authors: Markewitz Robert , Torge Antje , Wandinger Klaus-Peter , Pauli Daniela , Franke Andre , Bujanda Luis , Marimón José Maria , Banales Jesus M. , Gutierrez-Stampa María A. , Nafría Beatriz , Junker Ralf
Published: February 2021

Laboratory testing for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) consists of two pillars: the detection of viral RNA via rt-PCR as the diagnostic gold standard in acute cases, and the detection of antibodies against SARS-CoV-2. However, concerning the latter, questions remain about their diagnostic and prognostic value and it is not clear whether all patients develop detectable antibodies. We examined sera from 347 Spanish COVID-19 patients, collected during the peak of the epidemic outbreak in Spain, for the presence of IgA and IgG antibodies against SARS-CoV-2 and evaluated possible associations with age, sex and disease severity (as measured by duration of hospitalization, kind of respiratory support, treatment in ICU and death). The presence and to some degree the levels of anti-SARS-CoV-2 antibodies depended mainly on the amount of time between onset of symptoms and the collection of serum. A subgroup of patients did not develop antibodies at the time of sample collection. Compared to the patients that did, no differences were found. The presence and level of antibodies was not associated with age, sex, duration of hospitalization, treatment in the ICU or death. The case-fatality rate increased exponentially with older age. Neither the presence, nor the levels of anti-SARS-CoV-2 antibodies served as prognostic markers in our cohort. This is discussed as a possible consequence of the timing of the sample collection. Age is the most important risk factor for an adverse outcome in our cohort. Some patients appear not to develop antibodies within a reasonable time frame. It is unclear, however, why that is, as these patients differ in no respect examined by us from those who developed antibodies.
Colonization by arbuscular mycorrhizal fungi improves salinity tolerance of eucalyptus (Eucalyptus camaldulensis) seedlings
Authors: Klinsukon Chaiya , Lumyong Saisamorn , Kuyper Thomas W. , Boonlue Sophon
Published: February 2021

Soil salinity affects soil quality and reduces plant performance. Arbuscular mycorrhizal fungi (AMF) can enhance the tolerance of plants under salinity stress. Cultivation of eucalyptus (Eucalyptus camaldulensis), which exhibits high water use efficiency, is possible in saline areas to produce raw materials for the pulp industry. We determined the effects of arbuscular mycorrhizal fungi (AMF) on the growth and survival of eucalyptus seedlings under saline conditions. Three different clones of eucalyptus seedlings were pre-inoculated with three salt-tolerant AMF species, namely Glomus sp.2, Gigaspora albida and G. decipiens, and without pre-inoculation. The seedlings were grown in a greenhouse for 45 days. They were then transferred to individual pots, filled with field soil and subsequently treated with NaCl solution until electro-conductivity (EC) reached 10, 15 and 20 dS m−1. They were watered for 90 days under nursery conditions. The results show that increased salinity levels reduced plant performance, fractional AMF root colonization, spore number, and eucalypt K/Na ratio. AMF significantly increased chlorophyll and decreased leaf proline concentrations by more than 50% and 20% respectively and increased the K/Na ratio three- to six-fold compared with non-inoculated plants. Pre-inoculation with AMF before outplanting also improved plant performance by more than 30% under salinity stress compared to non-inoculated plants. We conclude that AMF can alleviate the negative impacts of salinity on plant physiological and biochemical parameters.
Apigenin protects mice against 3,5-diethoxycarbonyl-1,4-dihydrocollidine-induced cholestasis
Authors: Zheng Shihong , Cao Peichang , Yin Zequn , Wang Xuerui , Chen Yuanli , Yu Maoyun , Xu Baocai , Liao Chenzhong , Duan Yajun , Zhang Shuang , Han Jihong , Yang Xiaoxiao
Published: February 2021

Apigenin prevented the DDC-induced abnormal lipid metabolism, liver damage and liver fibrosis by reducing inflammation and oxidative stress. Apigenin might be a potential drug for the treatment of cholestatic liver diseases.
Effects of a Myrciaria jaboticaba peel extract on starch and triglyceride absorption and the role of cyanidin-3-O-glucoside
Authors: Alves Castilho Pamela , Bracht Lívia , Barros Lillian , Albuquerque Bianca R. , Dias Maria Inês , Ferreira Isabel C. F. R. , Comar Jurandir Fernando , Barlati Vieira da Silva Tamires , Peralta Rosane Marina , Sá-Nakanishi Anacharis Babeto de , Bracht Adelar
Published: February 2021

Inhibition of triglyceride absorption by Myrciaria jaboticaba is strongly dependent on the participation of cyanidin-3-O-glucoside, which inhibits free fatty acid absorption.
Caffeine promotes the expression of telomerase reverse transcriptase to regulate cellular senescence and aging
Authors: Tao Li , Zhang Wei , Zhang Yaxin , Zhang Mei , Zhang Yueying , Niu Xing , Zhao Qing , Liu Zhenxing , Li Yuyin , Diao Aipo
Published: February 2021

Caffeine promotes expression of TERT, consequently increases telomere length, prevents cellular senescence and delays aging phenotypes in mice.
A strategy for programming the regulation of in vitro transcription with application in molecular circuits
Authors: Hu Yingxin , Xie Chun , Xu Fei , Pan Linqiang
Published: February 2021

A strategy for programming the regulation of in vitro transcription with a variable number of inputs was proposed. Based on this strategy, various circuits such as logic circuits, parallel transcription circuits, and cascading circuits were constructed.
Understanding charge transport in wavy 2D covalent organic frameworks
Authors: Martínez-Abadía Marta , Strutyński Karol , Stoppiello Craig T. , Lerma Berlanga Belén , Martí-Gastaldo Carlos , Khlobystov Andrei N. , Saeki Akinori , Melle-Franco Manuel , Mateo-Alonso Aurelio
Published: February 2021

A new wavy 2D covalent organic framework shines light on the structural factors that dominate charge transport.
Photoresponsive dynamic covalent bond based on addition–fragmentation chain transfer of allyl selenides
Authors: Chen Sisi , Liu Ming , Zhang Jiandong , Zhang Zhengbiao , Zhu Jian , Pan Xiangqiang , Zhu Xiulin
Published: February 2021

A new dynamic covalent bond allyl selenide that can undergo a reversible addition–fragmentation chain transfer reaction under ultraviolet irradiation.
A facile approach for the preparation of liquid crystalline polyurethane for light-responsive actuator films with self-healing performance
Authors: Shen Wenbo , Du Bin , Liu Jiaoshi , Zhuo Haitao , Yang Chuluo , Chen Shaojun
Published: February 2021

A facile approach was developed to prepare liquid crystalline polyurethane by quaternization between ordinary polyurethane and liquid crystalline monomers to yield a fast light-responsive actuator film with self-healing performance.
Facile syntheses of tetrahydroquinolines and 1,2-dihydroquinolines via vinylogous cascade hydride transfer/cyclization
Authors: Guo Mengzhu , Dong Fengying , Yin Xiangcong , Xu Lubin , Wang Liang , Li Shuai-Shuai
Published: February 2021

The medicinally significant 3-monosubstituted tetrahydroquinolines and 1,2-dihydroquinolines were controllably constructed via redox-neutral vinylogous cascade condensation/[1,5]-hydride transfer/cyclization in EtOH.
Metabolomic profiling to reveal the therapeutic potency of Posidonia oceanica nanoparticles in diabetic rats
Authors: Ammar Naglaa M. , Hassan Heba A. , Mohammed Mona A. , Serag Ahmed , Abd El-Alim Sameh Hosam , Elmotasem Heba , El Raey Mohamed , El Gendy Abdel Nasser , Sobeh Mansour , Abdel-Hamid Abdel-Hamid Z.
Published: February 2021

The potential of P. oceanica butanol extract encapsulated in gelatin nanoparticles as a promising and effective antidiabetic therapy has been investigated via metabolomics.
Demonstration of the photothermal catalysis of the Sabatier reaction using nickel nanoparticles and solar spectrum light
Authors: Steeves Timothy McCormick , Esser-Kahn Aaron P.
Published: February 2021

The promise of light-to-chemical energy conversion has led researchers to explore photo-thermal processes for chemical reactivity of nanoparticles.
Regenerating heavily biofouled dissolved oxygen sensors using bacterial viruses
Authors: Bayat Fereshteh , Maddiboina Dhanyasri , Didar Tohid F. , Hosseinidoust Zeinab
Published: February 2021

Lytic bacteriophages can be utilized as a non-invasive method for removing bacterial biofilms formed on the surface of gas permeable membranes of dissolved oxygen sensors.
Insight into single-element nobel metal anisotropic silver nanoparticle shape-dependent selective ROS generation and quantification
Authors: Ahmad Jabran , Memon Abdul Ghaffar , Shaikh Asif Ahmed , Ismail Tariq , Giwa Abdulmoseen S. , Mahmood Awais
Published: February 2021

Study investigated single element noble metal nanoparticle shape-dependent ROS generation and quantification, and investigated selective ROS species action on microbes.
Light driven molecular lock comprises a Ru(bpy)2(hpip) complex and cucurbit[8]uril
Authors: Yang Xiaona , Li Jie , Jiang Song , Xie Puhui , Liu Guoxing , Zheng Xin , Cao Zhanqi , Zheng Xianfu , Zou Dapeng , Wu Yangjie , An Wankai
Published: February 2021

Upon light irradiation, complex 1 was transformed from a U-shaped conformation to an interlocked complex.
Hierarchical hollow structured NixCo3−xO4 particles for high-performance hybrid supercapacitors with ultralong cyclic stability
Authors: Li Fanggang , Zheng Maojun , Zhang Wenlan , You Yuxiu , Jiang Dongkai , Yuan Hao , Ma Li , Shen Wenzhong
Published: February 2021

Hierarchical hollow NixCo3−xO4 particles possess sufficient active sites and exhibit superhigh energy density and ultralong cyclic stability.
From 3D hierarchical microspheres to 1D microneedles: the unique role of water in the morphology control of ferrocenylpyrrolidine C60 microcrystals
Authors: Peng Zhiyao , Su Mingming , Jiang Jintian , Ma Guoming , Zhang Ruiling , Yu Ao , Peng Ping , Li Fang-Fang
Published: February 2021

Water-regulated morphology engineering of a fullerene derivative was investigated. The addition of water promotes the morphological evolution from 3D hierarchical microspheres to 1D microneedles, and enhances the photoelectric performance.
Stencil mask defined doctor blade printing of organic single crystal arrays for high-performance organic field-effect transistors
Authors: Xi Yue , Wang Tao , Mu Qi , Huang Congcong , Duan Shuming , Ren Xiaochen , Hu Wenping
Published: February 2021

A novel printing method to realize a solution processed large-area, high-resolution organic single crystal array for OFET applications.
Synthesis of core–shell Ce-modified mixed metal oxides derived from P123-templated layered double hydroxides
Authors: Wang Kaijun , Mao Qifan , Fei Weimin , Kong Lingxin , Cao Xiaoyan , Gu Zhenggui
Published: February 2021

A shell of P123-templated CeMgAl-LDO was distributed in transverse and longitudinal directions on spheres of SiO2. The composites displayed high catalytic activity in the synthesis of propylene glycol methyl ether.
Tuning energy landscapes and metal–metal interactions in supramolecular polymers regulated by coordination geometry
Authors: Bäumer Nils , Kartha Kalathil K. , Buss Stefan , Maisuls Iván , Palakkal Jasnamol P. , Strassert Cristian A. , Fernández Gustavo
Published: February 2021

In this article, we exploit coordination geometry as a new tool to control the energy landscape and photophysical properties (red vs. blue luminescence) of supramolecular polymers.
A gill-mimicking thermoelectric generator (TEG) for waste heat recovery and self-powering wearable devices
Authors: Zhu Yuxiang , Xu Weiheng , Ravichandran Dharneedar , Jambhulkar Sayli , Song Kenan
Published: February 2021

This research studies the thermoelectric properties and the interface quality of polyaniline/MWNT composites. A gill-mimicking structured fTEG was developed to harvest body temperature and to power a biosensing system.
Relationship and Social Network Change in People With Impaired Social Cognition Post Right Hemisphere Stroke
Authors: Hewetson Ronelle , Cornwell Petrea , Shum David H. K.
Published: February 2021

Purpose

This article investigated relationship and social network change in the presence of a social cognition impairment post right hemisphere (RH) stroke. Impaired emotion perception and inferential reasoning are sources of interpersonal difficulty in people with social cognition impairment after traumatic brain injury. People with an RH stroke have also been identified as vulnerable to interpersonal relationship change. However, the influence of impairments in particular domains of communication or cognition on relationship and social network maintenance is yet to be explored.

Method

A multiple-case study methodology allowed for testing of theoretically developed propositions by exploring social networks and relationships within and between seven participant–proxy dyads. Purposeful recruitment was based on first-onset RH stroke and impaired social cognition, as determined by The Awareness of Social Inference Test.

Results

Social network size reduction (71.4%,n= 5) and interpersonal relationship change (85.7%,n= 6) were attributed to altered communication style, impairments in social cognition, and reduced insight and/or motivation. The spouse emerged as a facilitator of social engagement.

Conclusion

This study contributes to our understanding of the challenges experienced by people with impaired social cognition post RH stroke in maintaining relationships and their social networks.
Microwave functionality of spintronic devices implemented in a hybrid complementary metal oxide semiconductor and magnetic tunnel junction technology
Authors: Ma Rui , Sidi El Valli Ahmed , Kreißig Martin , Di Pendina Gregory , Protze Florian , Ebels Ursula , Prenat Guillaume , Chavent Antoine , Iurchuk Vadym , Sousa Ricardo , Vila Laurent , Ellinger Frank , Langer Jürgen , Wrona Jerzy , Prejbeanu Ioan‐Lucian
Published: February 2021

This letter presents magnetic tunnel junction based spintronic devices completely implemented in a hybrid semiconductor process that comprises a complementary metal oxide semiconductor and a magnetic tunnel junction technology. To demonstrate the coexistence of both complementary metal oxide semiconductor circuits and magnetic tunnel junction based spintronic devices, a proof‐of‐concept circuit prototype comprising 40 spintronic devices and a digital complementary metal oxide semiconductor serial peripheral interface is fabricated. According to measurement results, a selected spintronic device from the magnetic tunnel junction array, when surrounded by an external out‐of‐plane magnetic field of 1 kOe, emitted microwave signals from 2.235 to 2.464 GHz with an output power from 0.88 to 0.72 nW, when the DC current was increased from 0.6 to 1.0 mA. To the authors' best knowledge, this is the first work demonstrating the functionality of spintronic oscillators fully integrated in complementary metal oxide semiconductor circuit implemented in a hybrid complementary metal oxide semiconductor and magnetic tunnel junction process.
Self‐supervised learning with randomised layers for remote sensing
Authors: Jung Heechul , Jeon Taegyun
Published: February 2021

This letter presents a new self‐supervised learning approach based on randomised layers for remote sensing. Our method is basically based on the Tile2Vec approach, which is one of the state‐of‐the‐art self‐supervised learning approaches for remote sensing. Unlike the original Tile2Vec algorithm, we reformulate the triplet loss as a classification loss. We use several fully connected layers with binary cross‐entropy loss instead of no fully connected layers with triplet loss of the original Tile2Vec. We observe that not updating the fully connected layers is more helpful in obtaining more robust representations. The proposed algorithm is verified and evaluated by applying it to a cropland data layer classification task. The experimental results show that our approach is superior to the original Tile2Vec approach in all experiments based on random forest, logistic regression, and multi‐layer classifiers.
Spatial attention model‐modulated bi‐directional long short‐term memory for unsupervised video summarisation
Authors: Zhong Rui , Xiao Diyang , Dong Shi , Hu Min
Published: February 2021

Compared with surveillance video, user‐created videos contain more frequent shot changes, which lead to diversified backgrounds and a wide variety of content. The high redundancy among keyframes is a critical issue for the existing summarising methods in dealing with user‐created videos. To address the critical issue, we designed a salient‐ area‐size‐based spatial attention model (SAM) on the observation that humans tend to focus on sizable and moving objects in videos. Moreover, the SAM is taken as guidance to refine frame‐wise soft selected probability for the bi‐directional long short‐term memory model. The reinforcement learning framework, trained by the deep deterministic policy gradient algorithm, is adopted to do unsupervised training. Extensive experiments on the SumMe and TVSum datasets demonstrate that our method outperforms the state‐of‐the‐art in terms of F‐score.
Analysis of feasibility and advantages of multi‐source image registration using regional features
Authors: Zeng Liang , Lu Danwei , Zhu Qingtao , Xing Cheng , Yin Junjun , Yang Jian
Published: February 2021

Automatic registration of multi‐source remote sensing data is a challenging task due to the high non‐linearity of radiometric differences among various data. Feature extraction is a key enabling technique in registration algorithm design. In this letter, we prove the feasibility of using extracted regional features for multi‐source image registration. In particular, regional features can be extracted through pixel‐level image classification, and existing off‐the‐shelf algorithms can be directly adopted. Experiment results demonstrate the robustness of the regional‐feature‐based registration method.
Analysing the relationship between weather, built environment, and public transport ridership
Authors: Lin Pengfei , Weng Jiancheng , Brands Devi K. , Qian Huimin , Yin Baocai
Published: February 2021

For a sustainable public transport system, it is important to unveil the spatiotemporal characteristics of ridership and identify the influence mechanisms. Some studies analysed the effects of weather and built environment separately, however, their effects when incorporated remains to be determined. Using smart card data, weather information, and point of interest data from Beijing, the Light Gradient Boosted Machine was employed to investigate the relative importance of weather and built environment variables contributing to daily ridership at the traffic analysis zone level, and investigate the non‐linear relationship and interaction effects between them. Weather conditions and built environment contribute 30.22 and 55.83% to ridership fluctuations, respectively. Most variables show complex non‐linear and threshold effects on ridership. The interaction effects of weather and weekend/public holiday have a more substantial influence on ridership than weekdays, indicating weather conditions have less impact on regular commuting trips than discretionary trips. The ridership fluctuations in response to changing weather conditions vary with spatial locations. Adverse weather, such as strong wind, high humidity, or heavy rainfall, has a more disruptive impact on leisure‐related areas than on residence and office areas. This study can benefit stakeholders in making decisions about optimising public transport networks and scheduling service frequency.
Geometric correction code‐based robust image watermarking
Authors: Zhou Zhili , Zhu Jianyu , Su Yuecheng , Wang Meimin , Sun Xingming
Published: February 2021

Digital image watermarking is one of the effective schemes to protect the copyrights of still images. However, the existing watermarking schemes are still not robust enough to the common geometric transformation attacks such as arbitrary rotation, scaling and shifting with desirable hiding capacity. To address this issue, we propose a robust watermarking scheme based on geometric correction codes (GCCs). In this scheme, the watermark and pre‐set GCCs are combined and embedded into a cover image to obtain the watermarked image. At the stage of watermark extraction, the watermarked image, under a variety of geometric transformation attacks, can be geometrically corrected by minimising the difference between the extracted and the original GCCs, then the watermark is extracted from the watermarked image. The experiments demonstrate that, compared to the typical watermarking schemes, the proposed scheme achieves much higher robustness to the common geometric transformation attacks and comparable invisibility with the same embedding capacity.
Cellulose nanocrystals/water‐based polyurethane nanocomposite films with excellent wear resistance and softness
Authors: Liu Rongrong , Zhu Feichao , Hu Jinqing , Li Jinzhe , Han Jian
Published: February 2021

Waterborne polyurethane (WBPU) has the advantages of environmental, excellent film‐forming property and high bonding strength. However, the mechanical strength of waterborne polyurethane in coating products is not enough, and its wear resistance and softness are poor. In this paper, the Cellulose Nanocrystals (CNC) AQ3 obtained by acid hydrolysis of microcrystalline cellulose was successfully dispersed in the waterborne polyurethane matrix to prepare nanocomposite films with different contents. The mechanical properties, thermal properties, wear resistance and softness of the nanocomposite films were studied by Thermogravimetric (TG), tensile test, dry friction test and KES test. The morphology of CNC dispersed in waterborne polyurethane matrix was studied by Scanning electron microscope (SEM). The results show that the lower content of CNC was uniformly dispersed in the waterborne polyurethane matrix and the interaction between the two forms hydrogen bonds. Compared with waterborne polyurethane, the initial degradation temperature of the nanocomposite films made by adding only 1 wt% CNC increased by 50°C, the tensile strength increased by 179.3%, the wear resistance increased by 19%, and the minimum bending stiffness B reached 0.161 (gf·cm2). The results of this study can be used for textile coating applications, such as polyurethane synthetic leather.
Study on adsorption of Cd2+ by Ti‐pillared montmorillonite‐mixed activated carbon
Authors: Zhao Xuxia , Tuo Biyang , Long Sen , Song Xiang , Wan Li , Xiang Haichun
Published: February 2021

In this study, the composite of Ti‐pillared montmorillonite‐mixed activated carbon (TPM‐AC) was prepared by the water immersion method, and the adsorption of Cd2+ was studied under static conditions. A series of single experiments were conducted to determine the effects of the solution pH, adsorption time, initial Cd2+ concentration, and solution temperature on adsorption performance. The adsorption kinetics, isotherms, and thermodynamics behaviours of Cd2+ onto TPM‐AC were investigated. The results showed that the Brunauer–Emmett–Teller specific surface area and pore volume of TPM‐AC are increased, the crystallinity is greatly improved, and porous structural material with a large specific surface area is formed. The adsorption of Cd2+ by TPM‐AC is excellent and better than that of AC and TPM. The adsorption of Cd2+ by TPM‐AC, AC, and TPM can be described by the pseudo‐second‐order kinetic equation, and the adsorption isotherm is more consistent with the Langmuir isotherm model. The RL values of the dimensionless separation constants are all between 0 and 1, indicating that adsorption of Cd2+ is a relatively easy adsorption process. The values of thermodynamic parameters indicated that the adsorption is a reverse spontaneous and endothermic process.
Preparation of 2D ultrathin titanium dioxide nanosheets with enhanced visible‐light photocatalytic activity
Authors: Dai Zideng , Song Xue‐Zhi , Tang Fan , Kang Xiaolan , Liu Sihang , Abe Hiroya , Ohara Satoshi , Tan Zhenquan
Published: February 2021

The two‐dimensional (2D) ultrathin titanium dioxide (TiO2) nanosheets with large specific surface area and fast electron transfer are successfully fabricated by using P123 as a soft template during a conventional hydrothermal process. Ultrathin structure improves the lifetime of the photogenerated electron and hole. The bandgap of the 2D materials is reduced with the calcination treatment. The TiO2 nanosheets calcined at 300°C exhibit higher photocatalytic activity in degradation of methylene blue and rhodamine B under visible light irradiation, and excellent photoelectrochemical performance allow them a wide use in energy and environmental applications.
DC–DC Series‐resonant converter with multi‐stage current‐driven for balance charger of series‐connected lithium‐ion batteries
Authors: Farahani Gholamreza
Published: February 2021

Here, a novel DC–DC converter based on a series‐resonant inverter and a multi‐stage current‐driven rectifier for the active balance charger of lithium‐ion series batteries is proposed. In the proposed topology, diodes are placed in a current‐driven half‐wave rectifier to regulate the voltage at the terminals of the batteries. The proposed balance charger has been compared with the Cockcroft–Walton voltage multiplier, DC–DC multilevel boost converter, chain structure using an additional capacitor, and series‐resonant voltage multiplier topologies. The cost of the proposed topology has not increased in comparison to other topologies and can be made modularly and more stages can be increased by adding capacitors and diodes. The experimental results are obtained from charging six lithium‐ion series batteries, of which one of them has been damaged. All topologies balance and charge the rest of the batteries despite the damaged battery. The results show that the proposed topology for the converter has reduced the average balancing and charging time by 40.77% and 13.33%, respectively, compared to other topologies. Therefore, the energy losses of the proposed topology are less than the other topologies. Also, the higher energy efficiency of the proposed topology is expected due to the faster‐balancing speed.
Modified natural frame control of single‐phase cascaded H‐bridge multilevel converter under distorted grid voltage
Authors: Yang Daliang , Chen Shuang , Zhang Xuan , Yang Linhang , Liu Jinbao , Shao Dashuai
Published: February 2021

Cascaded H‐bridge multilevel converter is widely applied in flexible AC transmission and grid connection of renewable energy, but its current quality decreases as the grid voltage distortion continues to deteriorate. A modified natural frame control method to enhance the harmonic elimination ability of converters is proposed in this paper. A single‐phase cascaded delayed signal cancellation operator is applied to deal with the distorted grid voltage signals. Benefit from a system structure without any feedback loops or integral items, the transient response of single‐phase cascaded delayed signal cancellation operator is faster than commonly‐used second‐order generalised integrator. The settling time of single‐phase cascaded delayed signal cancellation operator facing grid voltage phase jump is less than one grid period. After immunising the synchronisation reference against harmonic distortion by using the single‐phase cascaded delayed signal cancellation operator, the modified natural frame control method can then generate high‐quality sinusoidal current. Phase‐locked loop and coordinate transformation are unnecessary for the proposed method, which decreases the system complexity. Various simulations and experimental tests based on a down‐scaled platform demonstrate the performance of the proposed modified natural frame control method under distorted grid voltage.
Bidirectional DC–DC converter based multilevel battery storage systems for electric vehicle and large‐scale grid applications: A critical review considering different topologies, state‐of‐charge balancing and future trends
Authors: Eroǧlu Fatih , Kurtoǧlu Mehmet , Vural Ahmet Mete
Published: February 2021

The expanding share of renewable energy sources (RESs) in power generation and rise of electric vehicles (EVs) in transportation industry have increased the significance of energy storage systems (ESSs). Battery is considered as the most suitable energy storage technology for such systems due to its reliability, compact size and fast response. Power converters are vital for the integration of batteries into power grid and EVs as they play an active role in both power conversion and battery management. Multilevel converters (MLCs) are types of power converters and attract widespread interest due to their improved power quality, reliability and modularity. There are two main challenges in MLC based battery storage systems (BSSs) which are selecting a proper MLC topology and balancing state‐of‐charges (SOCs) of batteries. Although some research has been carried out on either MLCs or SOC balancing, no single study exists which presents a comprehensive review on MLC based BSSs for large‐scale grid and EV applications. This paper begins by reviewing several major battery storage technologies that are utilised in MLC based BSSs. Later on, a systematical review of commonly used and recently proposed MLC topologies for BSSs are provided along with different control schemes for MLCs by specifically focusing on SOC balancing techniques. Finally, potential challenges and suggestions for future improvement of MLC based BSSs are addressed.
Comprehensive coordinated control strategy of PMSG‐based wind turbine for system inertia support
Authors: Zhu Ying , Liu Sheng , Wang Wei
Published: February 2021

With the increasing proportion of wind energy in the power system, wind turbines (WTs) need to have a certain system inertia support capability. This paper proposes a comprehensive coordinated control strategy of permanent magnet synchronous generators (PMSGs) based wind turbines for the system inertia support. Firstly, a variable coefficient integrated inertial control method is proposed to adjust the output of the wind turbine with the size of the disturbance. Secondly, a virtual capacitor control strategy is added and then the generator‐side converter can provide a much larger virtual capacitance than the DC‐side capacitance to provide fast, transient additional power support. Furthermore, the pitch angle de‐loading control is adopted when the wind speed exceeds the rated value for maintaining the stability of the system frequency. The comprehensive coordinated control strategy proposed in this paper can effectively give the system inertia support by realizing certain frequency regulation of wind turbines under various wind conditions and frequency fluctuations. The frequency response characteristics of PMSGs based wind turbines are studied in MATLAB/Simulink and the simulation results are presented to verify the effectiveness of the comprehensive coordinated control strategy.
Performance characteristics and reliability assessment of self‐excited induction generator for wind power generation
Authors: Varshney Lokesh , Vardhan Aanchal Singh S. , Vardhan Akanksha Singh S. , Kumar Sachin , Saket R.K. , Sanjeevikumar P.
Published: February 2021

The
paper presents the performance analysis‐based reliability
estimation of a self‐excited induction
generator (SEIG) using the Monte‐Carlo simulation (MCS)
method with data obtained from a self‐excited induction
motor operating as a generator. The global acceptance of a SEIG depends on its
capability to improve the system's poor voltage regulation and frequency
regulation. In the grid‐connected induction
generator, the magnetizing current is drawn from the grid, making the grid
weak. In contrast, in the SEIG stand‐alone operation, an external capacitor
arrangement is implemented to render the reactive power support. This capacitor
arrangement is connected across the stator terminals during the stand‐alone configuration of SEIG. The capacitor serves two purposes,
which include voltage build‐up and power factor
improvement. Therefore, the paper deals with obtaining the minimum capacitor
value required for SEIG excitation in isolated mode applications, including
stand‐alone wind power generation. The SEIG performance
characteristics have been evaluated for different SEIG parameters. The
simulation and experimental results are then compared and found satisfactory.
Then, SEIG reliability is estimated considering the MCS method utilizing SEIG
excitation's failure and success rates during experimental work in the
laboratory. Finally, the SEIG reliability evaluation is performed considering
different wind speeds.
Controller design for DFIG‐based WT using gravitational search algorithm for wind power generation
Authors: Bharti Om Prakash , Sarita Kumari , Vardhan Aanchal Singh S. , Vardhan Akanksha Singh S. , Saket R. K.
Published: February 2021

This paper describes the controller design aspects of DFIG‐based wind turbine system (WTS) using gravitational search algorithm (GSA). The appropriate control schemes are required for efficient and reliable functioning of the DFIG‐based wind energy conversion system (WECS). The control algorithms are implemented in converters which are placed in the rotor end and grid side of the WECS. The controller design schemes are optimized for accurate, reliable and stable operations of WECS using GSA. The most commonly used other design techniques are bacterial foraging optimization (BFO), and particle swarm optimization (PSO). Moreover, the transfer function modeling of DFIG is also described in this paper. The results show that the proposed GSA technique with sixths order transfer function model of DFIG improves the transient performance including time of rising the response to 90%, settling time, and amplitude of peak overshoot. The proposed GSA technique is compared with the techniques already implemented in the previous research works including PSO and BFO. The DFIG‐based WTS's output waveforms of voltage at dc‐link, reactive power, and active power are improved using GSA based design technique. Finally, it is concluded that the GSA technique gives better results as compared with the PSO and BFO techniques.
Fizeau et l’entraÎnement partiel de l’éther
Authors: Mathevet Renaud , Labastie Pierre , Lahaye Thierry
Published: February 2021

Entre 1849 et 1851, Hippolyte Fizeau a réalisé successivement trois expériences fondamentales relatives à la vitesse de la lumière. Ce sont toutes trois de véritables tours de force expérimentaux qui ont eu des conséquences majeures dans l’évolution de nos conceptions de la lumière et, comme l’a attesté Albert Einstein lui-même, dans l’avènement de la relativité restreinte. Nous présentons à la fois le contexte et les conséquences historiques ainsi que la réplique moderne que nous avons réalisée de l’expérience de 1851 dite « d’entraînement partiel de l’éther ».
L’imagerie optique de nanoparticules luminescentes : de la détection de biomolécules au diagnostic in vitro
Authors: Mousseau Fanny , Yu Chao , Alexandrou Antigoni , Bouzigues Cédric
Published: February 2021

Pour détecter des biomolécules et pathogènes (protéines, virus, bactéries, …) avec des sensibilités satisfaisantes, il est actuellement nécessaire d’utiliser des appareils de laboratoires coûteux. En combinant les remarquables propriétés optiques des ions lanthanides à un lecteur simple couplé à un smartphone, nous démontrons comment développer un système de détection portable, rapide et ultrasensible.