bluuebunny/crossref_metadata_2025 huggingface dataset:
On the Convergence of Asynchronous Parallel Iteration with Unbounded Delays
Authors: Peng Zhimin , Xu Yangyang , Yan Ming , Yin Wotao
Published: December 2017

Recent years have witnessed the surge of asynchronous parallel (async-parallel) iterative algorithms due to problems involving very large-scale data and a large number of decision variables. Because of asynchrony, the iterates are computed with outdated information, and the age of the outdated information, which we calldelay, is the number of times it has been updated since its creation. Almost all recent works prove convergence under the assumption of a finite maximum delay and set their stepsize parameters accordingly. However, the maximum delay is practically unknown. This paper presents convergence analysis of an async-parallel method from a probabilistic viewpoint, and it allows for large unbounded delays. An explicit formula of stepsize that guarantees convergence is given depending on delays’ statistics. With$$p+1$$p+1identical processors, we empirically measured that delays closely follow the Poisson distribution with parameterp, matching our theoretical model, and thus, the stepsize can be set accordingly. Simulations on both convex and nonconvex optimization problems demonstrate the validness of our analysis and also show that the existing maximum-delay-induced stepsize is too conservative, often slows down the convergence of the algorithm.
Bigger, stronger, faster… pushing the envelope of 3D printers to turn them into true production tools
Authors: Mathijsen Django
Published: December 2017

The 3D printer has already matured into a useful and versatile tool for making models, mock-ups and prototypes. But researchers, engineers and designers are working hard to eliminate the limitations of 3D-printing and take the next step. The goal is to take the machine out of the lab and into the factory, from rapid prototyping to additive manufacturing. Reinforced Plastics talks to people on this new frontier, pushing out the boundaries of 3D printing.
Intact striatal dopaminergic modulation of reward learning and daily-life reward-oriented behavior in first-degree relatives of individuals with psychotic disorder
Authors: Kasanova Zuzana , Ceccarini Jenny , Frank Michael J. , van Amelsvoort Thérèse , Booij Jan , van Duin Esther , Steinhart Henrietta , Vaessen Thomas , Heinzel Alexander , Mottaghy Felix , Myin-Germeys Inez
Published: December 2017

Background

Abnormalities in reward learning in psychotic disorders have been proposed to be linked to dysregulated subcortical dopaminergic (DA) neurotransmission, which in turn is a suspected mechanism for predisposition to psychosis. We therefore explored the striatal dopaminergic modulation of reward processing and its behavioral correlates in individuals at familial risk for psychosis.

Methods

We performed a DA D2/3receptor [18F]fallypride positron emission tomography scan during a probabilistic reinforcement learning task in 16 healthy first-degree relatives of patients with psychosis and 16 healthy volunteers, followed by a 6-day ecological momentary assessment study capturing reward-oriented behavior in the everyday life.

Results

We detected significant reward-induced DA release in bilateral caudate, putamen and ventral striatum of both groups, with no group differences in its magnitude nor spatial extent. In both groups alike, greater extent of reward-induced DA release in all regions of interest was associated with better performance in the task, as well as in greater tendency to be engaged in reward-oriented behavior in the daily life.

Conclusions

These findings suggest intact striatal dopaminergic modulation of reinforcement learning and reward-oriented behavior in individuals with familial predisposition to psychosis. Furthermore, this study points towards a key link between striatal reward-related DA release and pursuit of ecologically relevant rewards.
ESP teacher education needs
Authors: Basturkmen Helen
Published: December 2017

Teaching English for academic purposes (EAP) and for specific purposes (ESP) are demanding areas in which to work. Teaching in these areas typically includes a range of tasks, such as investigating learner needs and specialist discourse, developing courses and materials in addition to classroom teaching. Therefore, teachers face a range of tasks which often require additional knowledge and skills. To date, the literature in EAP and ESP has tended to foreground the needs of learners and background the learning and knowledge needs of teachers. This plenary reviews themes in the literature on teacher education in ESP and reports on two research studies that investigated the practices and perspectives of experienced ESP and EAP teachers. Findings from the studies are discussed in relation to teacher education needs in this field.
Incorporating Observatory Data into Oceanography Courses
Authors: Hunter-Thomson Kristin , Lichtenwalner Sage , McDonnell Janice
Published: December 2017

OOI Teaching with Data Workshops; New Brunswick, New Jersey, 19–21 May 2017 (chemistry) and 2–4 June 2017 (geology)
Probing the Grain-Scale Processes That Drive Plate Tectonics
Authors: Cook Terri
Published: December 2017

New experimental data suggest that rock composition may play a critical role in forming and perpetuating shear zones.
Application of optimal band-limited control protocols to quantum noise sensing
Authors: Frey V. M. , Mavadia S. , Norris L. M. , de Ferranti W. , Lucarelli D. , Viola L. , Biercuk M. J.
Published: December 2017

Essential to the functionality of qubit-based sensors are control protocols, which shape their response in frequency space. However, in common control routines out-of-band spectral leakage complicates interpretation of the sensor’s signal. In this work, we leverage discrete prolate spheroidal sequences (a.k.a. Slepian sequences) to synthesize provably optimal narrowband controls ideally suited to spectral estimation of a qubit’s noisy environment. Experiments with trapped ions demonstrate how spectral leakage may be reduced by orders of magnitude over conventional controls when a near resonant driving field is modulated by Slepians, and how the desired narrowband sensitivity may be tuned using concepts from RF engineering. We demonstrate that classical multitaper techniques for spectral analysis can be ported to the quantum domain and combined with Bayesian estimation tools to experimentally reconstruct complex noise spectra. We then deploy these techniques to identify previously immeasurable frequency-resolved amplitude noise in our qubit’s microwave synthesis chain.
Identification of long non-coding RNAs in the immature and mature rat anterior pituitary
Authors: Han Dong-Xu , Sun Xu-Lei , Fu Yao , Wang Chang-Jiang , Liu Jian-Bo , Jiang Hao , Gao Yan , Chen Cheng-Zhen , Yuan Bao , Zhang Jia-Bao
Published: December 2017

Many long non-coding RNAs (lncRNAs) have been identified in several types of human pituitary adenomas and normal anterior pituitary, some of which are involved in the pathogenesis of pituitary adenomas. However, a systematic analysis of lncRNAs expressed at different developmental stages of normal pituitary, particularly in rats, has not been performed. Therefore, we contrasted two cDNA libraries of immature (D15) and mature (D120) anterior pituitary in rat that were sequenced on an Illumina HiSeq Xten platform, and a total of 29,568,806,352 clean reads were identified. Notably, 7039 lncRNA transcripts corresponded to 4442 lncRNA genes, and 1181 lncRNA transcripts were significantly differentially expressed in D15 and D120. In addition, 6839 protein-coding genes (<100 kb upstream and downstream) were the nearest neighbors of 4074 lncRNA genes. An interaction network of lncRNAs and the follicle-stimulating hormone beta-subunit (FSHb) gene was constructed using the lncRNATargets platform, and three novel lncRNAs were obtained. Furthermore, we detected the expression of the novel lncRNAs and ten highly expressed lncRNAs that were randomly selected through quantitative PCR (qPCR). The rat anterior pituitary lncRNA content identified in this study provides a more in-depth understanding of the roles of these lncRNAs in hormone and reproduction development and regulation in mammals.
Cardiovascular disease progression in female Zucker Diabetic Fatty rats occurs via unique mechanisms compared to males
Authors: Lum-Naihe Kelly , Toedebusch Ryan , Mahmood Abuzar , Bajwa Jamal , Carmack Terry , Kumar Senthil A. , Ardhanari Sivakumar , DeMarco Vincent G. , Emter Craig A. , Pulakat Lakshmi
Published: December 2017

Population studies have shown that compared to diabetic men, diabetic women are at a higher risk of cardiovascular disease. However, the mechanisms underlying this gender disparity are unclear. Our studies in young murine models of type 2 diabetes mellitus (T2DM) and cardiovascular disease show that diabetic male rats develop increased cardiac fibrosis and suppression of intracardiac anti-fibrotic cytokines, while premenopausal diabetic female rats do not. This protection from cardiac fibrosis in female rats can be an estrogen-related effect. However, diabetic female rats develop early subclinical myocardial deformation, cardiac hypertrophy via elevated expression of pro-hypertrophic miR-208a, myocardial damage, and suppression of cardio-reparative Angiotensin II receptor 2 (Agtr2). Diabetic rats of both sexes exhibit a reduction in cardiac capillary density. However, diabetic female rats have reduced expression of neuropilin 1 that attenuates cardiomyopathy compared to diabetic male rats. A combination of cardiac hypertrophy and reduced capillary density likely contributed to increased myocardial structural damage in diabetic female rats. We propose expansion of existing cardiac assessments in diabetic female patients to detect myocardial deformation, cardiac hypertrophy and capillary density via non-invasive imaging, as well as suggest miR-208a, AT2R and neuropilin 1 as potential therapeutic targets and mechanistic biomarkers for cardiac disease in females.
Photoreceptor metabolic reprogramming provides survival advantage in acute stress while causing chronic degeneration
Authors: Wubben Thomas J. , Pawar Mercy , Smith Andrew , Toolan Kevin , Hager Heather , Besirli Cagri G.
Published: December 2017

Photoreceptor death is the root cause of vision loss in many retinal disorders, and there is an unmet need for neuroprotective modalities to improve photoreceptor survival. The biosynthetic requirement of photoreceptors is among the highest in the body, and to meet this demand, photoreceptors maintain their ability to perform aerobic glycolysis. This highly regulated form of glycolysis allows cells to efficiently budget their metabolic needs and may be a critical link between photoreceptor function and survival. Pyruvate kinase muscle isozyme 2 (PKM2) is a key regulator of aerobic glycolysis. In the present study, we characterized the effect of PKM2 deletion on baseline functioning and survival of photoreceptors over time by utilizing a photoreceptor-specific, PKM2 knockout mouse model. We found that upon PKM2 deletion, PKM1 is upregulated in the outer retina and there is increased expression of genes involved in glucose metabolism, which led to chronic degenerative changes in the outer retina of these mice. We also discovered that this metabolic reprogramming provided a survival advantage to photoreceptors in an experimental model of retinal detachment. This study strongly supports the hypothesis that reprogramming metabolism may be a novel therapeutic strategy for photoreceptor neuroprotection during acute stress.
Structure and Interactions of A Host Defense Antimicrobial Peptide Thanatin in Lipopolysaccharide Micelles Reveal Mechanism of Bacterial Cell Agglutination
Authors: Sinha Sheetal , Zheng Liangzhen , Mu Yuguang , Ng Wun Jern , Bhattacharjya Surajit
Published: December 2017

Host defense cationic Antimicrobial Peptides (AMPs) can kill microorganisms including bacteria, viruses and fungi using various modes of action. The negatively charged bacterial membranes serve as a key target for many AMPs. Bacterial cell death by membrane permeabilization has been well perceived. A number of cationic AMPs kill bacteria by cell agglutination which is a distinctly different mode of action compared to membrane pore formation. However, mechanism of cell agglutinating AMPs is poorly understood. The outer membrane lipopolysaccharide (LPS) or the cell-wall peptidoglycans are targeted by AMPs as a key step in agglutination process. Here, we report the first atomic-resolution structure of thanatin, a cell agglutinating AMP, in complex with LPS micelle by solution NMR. The structure of thanatin in complex with LPS, revealed four stranded antiparallel β-sheet in a ‘head-tail’ dimeric topology. By contrast, thanatin in free solution assumed an antiparallel β-hairpin conformation. Dimeric structure of thanatin displayed higher hydrophobicity and cationicity with sites of LPS interactions. MD simulations and biophysical interactions analyses provided mode of LPS recognition and perturbation of LPS micelle structures. Mechanistic insights of bacterial cell agglutination obtained in this study can be utilized to develop antibiotics of alternative mode of action.
Dysregulation of Mir-196b in Head and Neck Cancers Leads to Pleiotropic Effects in the Tumor Cells and Surrounding Stromal Fibroblasts
Authors: Álvarez-Teijeiro Saúl , Menéndez Sofía T. , Villaronga M. Ángeles , Rodrigo Juan P. , Manterola Lorea , de Villalaín Lucas , de Vicente Juan C. , Alonso-Durán Laura , Fernández M. Pilar , Lawrie Charles H. , García-Pedrero Juana M.
Published: December 2017

The miR-196 family members have been found dysregulated in different cancers. Therefore, they have been proposed as promising biomarkers and therapeutic targets. This study is the first to investigate the role of miR-196b in the development and progression of head and neck squamous cell carcinomas (HNSCC), and also the impact on the surrounding tumor microenvironment. Increased miR-196b levels were detected in 95% of primary tumors and precancerous lesions, although no significant differences were observed between non-progressing versus progressing dysplasias. Furthermore, increased levels of both miR-196a and miR-196b were successfully detected in saliva samples from HNSCC patients. The functional consequences of altered miR-196 expression were investigated in both HNSCC cell lines and cancer-associated fibroblasts (CAFs) by transfection with specific pre-miR precursors. Results showed that both miR-196a and miR-196b elicit cell-specific responses in target genes and downstream regulatory pathways, and have a distinctive impact on cell proliferation, migration and invasion. These data reveal the early occurrence and prevalence of miR-196b dysregulation in HNSCC tumorigenesis, suggesting its utility for early diagnosis and/or disease surveillance and also as a non-invasive biomarker in saliva. The pleiotropic effects of miR-196a/b in HNSCC cell subpopulations and surrounding CAFs may complicate a possible therapeutic application.
Broadband absorption and enhanced photothermal conversion property of octopod-like Ag@Ag2S core@shell structures with gradually varying shell thickness
Authors: Jiang Qian , Zeng Wenxia , Zhang Canying , Meng Zhaoguo , Wu Jiawei , Zhu Qunzhi , Wu Daxiong , Zhu Haitao
Published: December 2017

Photothermal conversion materials have promising applications in many fields and therefore they have attracted tremendous attention. However, the multi-functionalization of a single nanostructure to meet the requirements of multiple photothermal applications is still a challenge. The difficulty is that most nanostructures have specific absoprtion band and are not flexible to different demands. In the current work, we reported the synthesis and multi-band photothermal conversion of Ag@Ag2S core@shell structures with gradually varying shell thickness. We synthesized the core@shell structures through the sulfidation of Ag nanocubes by taking the advantage of their spatially different reactivity. The resulting core@shell structures show an octopod-like mopgorlogy with a Ag2S bulge sitting at each corner of the Ag nanocubes. The thickness of the Ag2S shell gradually increases from the central surface towards the corners of the structure. The synthesized core@shell structures show a broad band absorption spectrum from 300 to 1100 nm. Enhanced photothermal conversion effect is observed under the illuminations of 635, 808, and 1064 nm lasers. The results indicate that the octopod-like Ag@Ag2S core@shell structures have characteristics of multi-band photothermal conversion. The current work might provide a guidance for the design and synthesis of multifunctional photothermal conversion materials.
Palladium pincer-type complexes and zwitterionic sulfur adducts of pyridine-bridged bis(1,2,3-triazolin-5-ylidenes): syntheses, characterizations and catalytic applications
Authors: Wang Haiying , Zhang Bo , Yan Xuechao , Guo Shuai
Published: December 2017

Different reactivities of pincer-type pyridine-bridged bis(mesoionic carbenes) towards palladium(ii) and elemental sulfur have been revealed.
Insulin degrading enzyme contributes to the pathology in a mixed model of Type 2 diabetes and Alzheimer’s disease: possible mechanisms of IDE in T2D and AD
Authors: Li Huajie , Wu Jian , Zhu Linfeng , Sha Luolin , Yang Song , Wei Jiang , Ji Lei , Tang Xiaochun , Mao Keshi , Cao Liping , Wei Ning , Xie Wei , Yang Zhilong
Published: December 2017

Insulin degrading enzyme (IDE) is believed to act as a junction point of Type 2 diabetes (T2D) and Alzheimer's disease (AD); however, the underlying mechanism was not completely clear yet. Transgenic APPSwe/PS1 mice were used as the AD model and were treated with streptozocin/streptozotocin (STZ) to develop a mixed mice model presenting both AD and T2D. Morris Water Maze (MWM) and recognition task were performed to trace the cognitive function. The detection of fasting plasma glucose (FPG) and plasma insulin concentration, and oral glucose tolerance test (OGTT) were used to trace the metabolism evolution. Aβ40 and Aβ42 were quantified by colorimetric ELISA kits. The mRNA or protein expression levels were determined by quantitative real-time RT-PCR and Western blotting analysis respectively. T2D contributes to the AD progress by accelerating and worsening spatial learning and recognition impairments. Metabolic parameters and glucose tolerance were significantly changed in the presence of the AD and T2D. The expression levels of IDE, PPARγ, and AMPK were down-regulated in mice with AD and T2D. PPARγ activator rosiglitazone (RSZ) or AMPK activator AICAR increased the expression level of IDE and decreased Aβ levels in mice with AD and T2D. RSZ or AICAR treatment also alleviated the spatial learning and recognition impairments in AD and T2D mice. Our results found that, in the mice with T2D and AD, the activators of PPARγ/AMPK signaling pathway significantly increased the expression level of IDE, and decreased the accumulation of Aβ40 and Aβ42, as well as alleviated the spatial learning and recognition impairments.
Targeted disruption of the Kcnj5 gene in the female mouse lowers aldosterone levels
Authors: Hardege Iris , Long Lu , Al Maskari Raya , Figg Nicola , O’Shaughnessy Kevin M.
Published: December 2017

Aldosterone is released from adrenal zona glomerulosa (ZG) cells and plays an important role in Na and K homoeostasis. Mutations in the human inwardly rectifying K channel CNJ type (KCNJ) 5 (KCNJ5) gene encoding the G-coupled inwardly rectifying K channel 4 (GIRK4) cause abnormal aldosterone secretion and hypertension. To better understand the role of wild-type (WT) GIRK4 in regulating aldosterone release, we have looked at aldosterone secretion in a Kcnj5 knockout (KO) mouse. We found that female but not male KO mice have reduced aldosterone levels compared with WT female controls, but higher levels of aldosterone after angiotensin II (Ang-II) stimulation. These differences could not be explained by sex differences in aldosterone synthase (Cyp11B2) gene expression in the mouse adrenal. Using RNAseq analysis to compare WT and KO adrenals, we showed that females also have a much larger set of differentially expressed adrenal genes than males (395 compared with 7). Ingenuity Pathway Analysis (IPA) of this gene set suggested that peroxisome proliferator activated receptor (PPAR) nuclear receptors regulated aldosterone production and altered signalling in the female KO mouse, which could explain the reduced aldosterone secretion. We tested this hypothesis in H295R adrenal cells and showed that the selective PPARα agonist fenofibrate can stimulate aldosterone production and induce Cyp11b2. Dosing mice in vivo produced similar results. Together our data show that Kcnj5 is important for baseline aldosterone secretion, but its importance is sex-limited at least in the mouse. It also highlights a novel regulatory pathway for aldosterone secretion through PPARα that may have translational potential in human hyperaldosteronism.
Design of LPF with UW stopband and sharp roll‐off rate using transfer function analysis
Authors: Vaezi A. , Geran Gharakhili F.
Published: December 2017

A novel microstrip lowpass filter with outstanding features is designed, simulated, fabricated and analysed. The proposed structure has the capability to improve frequency response in transition band and remove the 13th unwanted harmonics in the stopband. The proposed design comprises many resonators and cell attenuators. It features an UW stopband, high suppression factor and high sharp roll‐off. To adjust the cut‐off frequency, the transfer function and LC equivalent circuit of the main resonator are calculated. Results show that cut‐off frequency and relative bandwidth of stopband of the filter are 2 GHz and 171%, respectively. Also, insertion loss <0.11 dB and return loss more than 18 dB have obtained for filter form DC to 2 GHz. The fabricated filter reaches a high figure of merit of 72,093.
Modified concentric power swing blocker applicable in UPFC compensated line
Authors: Khodaparast Jalal , Khederzadeh Mojtaba
Published: December 2017

Flexible AC transmission systems (FACTS) devices have adverse impacts on the performance of distance relays (DRs) due to the fast intervention of the controllers of these devices during power swing. Power swing blocker (PSB) as the complementary part in a DR is designed to distinguish a fault from a power swing; meanwhile its performance in compensated lines needs to be investigated. The performance of concentric PSB (CPSB) is studied in transmission lines compensated by unified power flow controller (UPFC). It is shown that fast responses of proportional‐integral (PI) controllers of UPFC, reduce recorded time by CPSB significantly (it decreases by 90% of uncompensated condition) which makes DR to issue trip command during power swing condition. Detailed model of UPFC is simulated in three‐machine and New England power systems to show the deficiency of CPSB in compensated condition. In order to overcome the deficiency of the CPSB in UPFC‐compensated line, two remedial actions are proposed. The first method is based on modifying CPSB to solve the problem and the second method is based on modifying control loop of UPFC to prevent the problem. Both methods show their efficiency to overcome the deficiency.
Automatic segmentation and reconstruction of historical manuscripts in gradient domain
Authors: Baig Asim , Al‐Ma'adeed Somaya A.S. , Bouridane Ahmed , Cheriet Mohamed
Published: December 2017

Separating content from noise in historical manuscripts is a fundamental task in digital palaeography. This study presents a fully automated segmentation approach based on the response of Harris corner detectors. The strength and clustering efficiency of the detected corners in the manuscripts are evaluated and used to segment the content from the background and noise. In addition, a manuscript reconstruction technique is proposed from the gradient field using the Poisson method to guide the interpolation. This reconstruction is able to remove noise significantly and hence enhances the contrast of the content thus making it easier for users to read and process these documents. The proposed approaches are evaluated using various standard databases to highlight their effectiveness and robustness to a multitude of noise and writing styles. Subjective and objective evaluations of the experimental results show that these techniques are able to successfully segment and reconstruct a very diverse set of scanned documents. An analysis of the results has also shown that the proposed technique compares favourably against similar counterparts.
Towards an accurate and fast computation of discrete Tchebychev moments for binary and grey‐level images
Authors: Benrais Lamine , Baha Nadia
Published: December 2017

The discrete Tchebychef moments (DTMs) are a set of discrete orthogonal moments applied in the field of objects description and image analysis. They show great precision in providing precise features representation capability for any given image. While using these models seems to be the preferred way for object description, the trade‐off is the considerable calculation time they require. The goal is to explore the feasibility of preparing and using a pre‐calculated data structure for the computation of the DTMs. To make the pre‐calculated data structure possible, the sizing property of the DTMs is used. Experimental results show the equal accuracy of the calculated moments compared with the classic calculation process while realising a significant decrease in calculation time.
Clutter and terrain effects on path loss in the VHF/UHF bands
Authors: Faruk Nasir , Bello Olayiwola W. , Oloyede Abdulkarim A. , Surajudeen‐Bakinde Nazmat T. , Obiyemi Obiseye , Olawoyin Lukman A. , Ali Maaruf , Jimoh Abdulhameed
Published: December 2017

Path loss models are essential in the planning of wireless networks. However, the peculiar ambient characteristics of geographical locations necessitate a wide range of these models to take into consideration the different terrain dielectric, scattering irregularities, and clutter. This study investigates the effects of terrain and clutter on frequency‐dependent path loss models in the very high frequency (VHF) and ultra high frequency (UHF) bands using multi‐transmitter scenarios. Seven transmitters and 15 measurement routes were covered using an Agilent N9342C spectrum analyser. The measured results show that the models' prediction errors (PEs) follow the terrain profile and also that the clutter effects are noticeable along each route with varying degrees of impact. Near constant standard deviation errors (SDEs) were observed across all the models for the specific routes as well as a strong dependency on the terrain profile and clutters along the measurement routes. The UHF and VHF bands have average SDEs of 10.5 and 7.5 dB, respectively. A three‐dimensional digital elevation model (DEM) showing the terrain and PE was also developed. Contour lines were extracted from the advanced spaceborne thermal emission radiometer and global DEM data sets. Visualisation of the terrain profile was achieved in the ArcScene software environment.
Reconfigurable band‐rejection antenna for ultra‐wideband applications
Authors: Alam Md Shahidul , Abbosh Amin
Published: December 2017

A low‐profile, low cost reconfigurable antenna with on‐demand single‐ or dual‐band rejection capability for ultra‐wideband (UWB) applications is presented. A modified monopole structure is integrated with an arc‐shaped slot and two open‐ended L‐shaped stubs to realise the band rejection. The antenna operates in four modes: a full UWB (3.1–10.6 GHz) coverage antenna, a UWB antenna with a single‐band WiMax or wide local area network (WLAN) rejection, and a UWB antenna with dual‐band WiMax/WLAN rejection. On‐demand individual and simultaneous band‐rejections are implemented by controlling the arc‐slot and L‐stubs using three PIN diodes. Thus, the adopted control technique is quite easy and requires low operational power (approximately 40 mW max.). Details of the design process and reconfiguration mechanism are presented. The band‐rejection function is explained using equivalent circuits and surface current distribution at each mode. A prototype is built on the FR4 substrate and tested to validate the performances. The antenna exhibits stable radiation characteristics and almost flat gain (average 4 dBi) responses across the whole band, while significantly weak radiation and gain reduction (;7 dB) are achieved at the rejected bands. Therefore, this antenna is suitable for high‐performance UWB systems in WiMax/WLAN dense environments with the aim to improve signal quality, system capacity, and communication link efficiency.
Load‐independent harmonic mitigation in SCR‐fed three‐phase multiple adjustable speed drive systems with deliberately dispatched firing angles
Authors: Yang Yongheng , Davari Pooya , Blaabjerg Frede , Zare Firuz
Published: December 2017

Adjustable speed drives (ASD) are widely used in industry for energy savings, where low‐cost diode rectifiers are still employed as the front‐ends, also for simplicity in control and reliability in operation. However, significant harmonics appear at the grid, which should be tackled according to standards and/or grid‐connection rules. If not, a poor power quality will cause the efficiency of the entire system drop. Currently, communication technologies are still not very cost‐effective for industrial harmonic control in multiple parallel motor‐drive systems. Therefore, this study proposes a harmonic mitigation strategy for multiple ASD systems, where silicon‐controlled rectifiers (SCR) with boost converters in the dc‐link have been adopted to increase the harmonic‐current controllability. More specific, the SCR firing angles are deliberately dispatched among the drive units, which results in certain phase shifts of the SCR currents on purpose. Consequently, the harmonics appearing in the grid current can be mitigated to some extent without communication. The effectiveness is independent of an individual SCR system loading when a number of drives are connected. Simulations are carried out to verify the discussion. Furthermore, to maximize the harmonic cancellation, a customised modulation scheme has been experimentally demonstrated. Both simulation and experimental results have confirmed the analysis.
Gain‐scheduled constrained state feedback control of DC–DC buck power converter
Authors: Tarczewski Tomasz , Niewiara Łukasz J. , Skiwski Michał , Grzesiak Lech M.
Published: December 2017

A gain‐scheduled constrained state feedback controller (SFC) for a SiC MOSFET direct current (DC)–DC buck power converter with a non‐synchronous control strategy is presented. First, the synthesis process of a gain‐scheduled SFC for a control system with a state‐dependent parameter is proposed. Next, constraints of important states and control variables are a posteriori introduced into control algorithm to provide satisfactory dynamic behaviour and safe operation of the plant. The boundary values of control signals which provide permissible values of the future state‐space variables are derived from the models of power converters that take into account two modes of operation (i.e. charging and discharging mode). The novelty of the proposed approach lies in efficient control algorithm that utilises the gain‐scheduled SFC with the parameter‐dependent constraint handling method. The designed control algorithm is extensively tested through simulation and experiments at a switching frequency of 36 kHz. The proposed solution is further compared with a conventional cascade control structure based on two proportional integral controllers for voltage and current loops as well as with a non‐constrained state feedback control structure to illustrate its performance and low computational complexity.
Circuit model of transient cross‐coupling
Authors: Darney Ian Brook
Published: December 2017

Using a signal generator and an oscilloscope, measurements were made of the differential‐mode current and the common‐mode current in a twin‐conductor cable installed on a test rig, over a range of frequencies which included half‐wave resonances. Test data was used to assign component values to a Triple‐T circuit model of the assembly. This model was then transformed into a transient coupling model. The signal generator was reset to generate square waves, and photographs were taken of the waveforms of the input voltage and the common‐mode current. A close correlation was achieved between these waveforms and those of the transient coupling model. This demonstrates that the technique of circuit modelling and bench testing is reliable and accurate, in both the frequency domain and the time domain. The technique allows potential hazards due to transient interference to be analysed, tested, and quantified during the design process. Electromagnetic interference can be analysed without recourse to the mathematics of full‐field modelling. It is also shown that, from the point of view of Electromagnetic Compatibility, the concepts of the single‐point ground and the equipotential ground are both misleading and counter‐productive.
Representational learning approach for power system transient stability assessment based on convolutional neural network
Authors: Tan Bendong , Yang Jun , Pan Xueli , Li Jun , Xie Peiyuan , Zeng Ciling
Published: December 2017

The transient stability assessment (TSA) problem can be mapped into a two‐class classification problem in machine learning, which estimates the dynamic security boundary of the power system by learning from large amount samples. A representational learning approach is proposed to solve the problem based on big data collected from Phasor Measurement Units (PMUs), which includes four stages: (i) Construct original input features by using PMUs data to describe the dynamic characteristics of the power system. (ii) Unsupervised representational feature learning by using the original features. Stacked autoencoders (SAEs) perform representational learning for crucial features. (iii) Supervised classifier training. A powerful deep learning model, convolutional neural network, which is added to SAE, is trained and tested with the learned representation. (iv) Online application, the trained model is applied to the online evaluation for TSA. Simulation on the New England 39‐bus test system shows that the proposed approach has high accuracy, rare misclassification of the unstable sample and excellent robustness with noise in PMUs for TSA.
Optimal demand response aiming at enhancing the economy of high wind power penetration system
Authors: Zhou Xiao , Shi Jing , Kang Gong
Published: December 2017

Wind power, with its non‐polluting characteristic and free access, has been widely developed in the grid, and this trend is expected to continue in the future. However, the high penetration of wind energy brings challenges to the operation of power system. Demand response (DR) provides a better way for electric utility customers to match the power demand and supply. This article aims at enhancing the economy of high wind power penetration system operation. Firstly, the principle and characteristic of demand response is analyzed. Then a system operating cost optimization scheme considering the demand response is proposed. With the demand response, simulations proved that the capacity of system for accepting wind energy is improved, and the operating cost of system is reduced.
Research on dc infeed ratio of receiving grids with renewable energy under frequency stability constraint
Authors: Si Dajun , Qian Yingchun , Xing Facai , Dong Huanfeng , Guan Minyuan , Xu Zheng
Published: December 2017

With the rising renewable energy penetration and large capacity power infeed, receiving grids are challenged by the decreasing rotational inertia as well as primary frequency regulation ability and the increasing single dc infeed power. Based on the steady‐state and transient‐state frequency stability constraints, this study proposes a method to calculate the critical single dc infeed ratio with different renewable energy penetration and dc infeed ratio. Taking into consideration the renewable energy penetration and dc infeed ratio, the study first modified the traditional frequency deviation index. Then, the electromagnetic transient model of the receiving grid with renewable energy is established in PSCAD/EMTDC, and the influence of the gain coefficient in emulation inertia controllers, the installed capacity of wind farms, and the hydro power ratio on critical single dc infeed ratio were studied. The critical single dc infeed ratio is one of the operating requirements of the receiving grid, and it provides reference for installed capacity in power system planning.
Framework planning of active distribution network considering active management
Authors: Gao Peng , Chen Hongkun , Zheng Xu , Wu Bin
Published: December 2017

Taking active management measures and considering operating characteristics of distributed generation (DG) in the planning stage, a bi‐layer model on framework planning for active distribution network is built. The minimum annual total cost is regarded as the objective function for the upper layer of the built model while the minimum active management cost is taken as the objective function of lower layer of the built planning model. The upper and lower layers of the planning model are solved by tree structure coding partheno‐genetic algorithm and primal‐dual interior point method, respectively. Considering operating characteristics of DGs, a probability density function is obtained in accordance with historical data, and representative scenes are constructed based on Wasserstein distance. The test system demonstrates the validity and rationality of the bi‐layer planning model as well as the positive effect on DG's reducing network loss and improvements on system operations.
One‐step synthesis and characterisation of LuAG nanoparticles via solvothermal route
Authors: Xing Lin , Wang Conghui , Wang Xiujie , Ding Xingxing
Published: December 2017

Lutetium aluminium garnet (Lu3Al5O12, LuAG) nanoparticles were well prepared via a facile and low temperature one‐step solvothermal route using aluminium nitrate and lutetium nitrate as raw materials and ethylenediamine (en) solution as the reaction medium. Here, en was employed both as the chelating agent and structure‐directing agent. Influences of the reaction medium, temperature, time and dispersant on the synthesis of crystalline LuAG nanoparticles were investigated. Characterisation of LuAG nanoparticles was performed using X‐ray diffraction, Fourier transform infrared, transmission electron microscopy and selected area electron diffraction. Optimum synthesis conditions of single‐phase LuAG nanoparticles have been determined. The addition of citric acid as a dispersant can effectively decrease the particle size and increase dispersion of crystalline LuAG nanoparticles.
Multi‐binding biotinylated iron oxide nanoparticles as a promising versatile material for magnetic biomedical applications
Authors: Du Yimeng , Pong Philip W.T.
Published: December 2017

The tetrameric streptavidin and avidin both have four sites that can specifically bind with biotin. Taking advantage of this high affinity binding, it is possible to realise multi‐binding of biotinylated nanoparticles to avidin or streptavidin molecules. The iron oxide nanoparticles (IONPs) have been actively investigated in biomedical applications. In this work, biotinylated IONPs (biotin‐IONPs) with around 10.5 nm magnetic core size were synthesised. They exhibited long‐term hydrophilic stability, and the activity of the biotin content was verified by avidin‐horseradish peroxidase induced chromogenic experiment. These biotin‐IONPs were then studied as magnetic labels in substrate‐based and substrate‐free magnetic bio‐labelling scheme of alpha‐fetoprotein. The multi‐binding ability of these biotin‐IONPs with streptavidin functionalised detection antibody (streptavidin‐detection antibody) was proved both on microplate well surfaces and in solution. Consequently, biotin‐IONPs are promising magnetic label materials for the improvement of magnetic biodetection. In addition, the avidin‐induced biotin‐IONP assemblies were produced in MilliQ water solution and in water‐in‐oil microemulsion system. In summary, based on their multi‐binding nature, the biotin‐IONPs can be considered as a versatile material to improve the sensitivity of magnetic biodetection and to be further built into assemblies for future biomedical applications such as magnetic resonance imaging and target drug delivery.
Exploitation of semi‐sequential reactive ion etch processes to fabricate in‐plane Si structures
Authors: Zarei Sanaz , Mohajerzadeh Shams
Published: December 2017

The work reports on the exploitation of semi‐sequential deep reactive ion etching (RIE) processes for realisation of deep vertically etched Si structures on Si substrate applicable in fibre‐optic sensing systems. These processes employ different mixtures of gases including hexaflourosulphide, hydrogen and oxygen in a RIE system with a programmed passivation and etching sub‐cycles. In the so‐called semi‐sequential processes, the intermediate purging steps are eliminated, which results in remaining little trace of reactant gases from the previous sub‐cycle in the RIE machine's chamber, which can participate in the process of current sub‐cycle. For the sake of minimum optical losses, which are accomplished by highly smooth vertical sidewalls, several etching processes were applied. In these processes, by controlling the etching parameters such as the flow of gases, plasma power and timing of each subsequence, the process can be controlled for minimum under‐etch and surface roughness and maximum verticality of sidewalls. However, time and cost considerations should also be noted in the optimum fabrication process.
Effects of Co and Ni on visible light photocatalytic properties of layered double hydroxide films
Authors: Yu Huan , Wang Wei‐Wei , Li Jiao , Cong Ri‐Min
Published: December 2017

Altering the composition of layered double hydroxides (LDHs) is an effective method for changing their properties. In this study, LDH films with different compositions were fabricated on conductive cloth by using a hydrothermal method. Electron microscopy, X‐ray diffraction, and UV–vis diffuse reflectance spectroscopy were used to investigate the morphology, crystal structure, and optical properties of the LDH films. The photocatalytic activity of LDHs with different compositions in the degradation of methyl orange was investigated under visible light irradiation. Our experimental results show that the reductive sites (Ni(II) and Co(II)) of LDHs and the conductive substrate improve the separation of photogenerated charges and prevent the particle aggregation of LDHs. LDH films (NiAl‐LDHs, NiFe‐LDHs, and CoAl‐LDHs) with reductive sites (Ni(II) and Co(II)) exhibit higher visible light photocatalytic performance.
Efficiency of radial transport of ices in protoplanetary disks probed with infrared observations: the case of CO2
Authors: Bosman Arthur D. , Tielens Alexander G. G. M. , van Dishoeck Ewine F.
Published: December 2017

Context.Radial transport of icy solid material from the cold outer disk to the warm inner disk is thought to be important for planet formation. However, the efficiency at which this happens is currently unconstrained. Efficient radial transport of icy dust grains could significantly alter the composition of the gas in the inner disk, enhancing the gas-phase abundances of the major ice constituents such as H2O and CO2.

Aim.Our aim is to model the gaseous CO2abundance in the inner disk and use this to probe the efficiency of icy dust transport in a viscous disk. From the model predictions, infrared CO2spectra are simulated and features that could be tracers of icy CO2, and thus dust, radial transport efficiency are investigated.

Methods.We have developed a 1D viscous disk model that includes gas accretion and gas diffusion as well as a description for grain growth and grain transport. Sublimation and freeze-out of CO2and H2O has been included as well as a parametrisation of the CO2chemistry. The thermo-chemical code DALI was used to model the mid-infrared spectrum of CO2, as can be observed with JWST-MIRI.

Results.CO2ice sublimating at the iceline increases the gaseous CO2abundance to levels equal to the CO2ice abundance of ~10−5, which is three orders of magnitude more than the gaseous CO2abundances of ~10−8observed bySpitzer. Grain growth and radial drift increase the rate at which CO2is transported over the iceline and thus the gaseous CO2abundance, further exacerbating the problem. In the case without radial drift, a CO2destruction rate of at least 10−11s−1or a destruction timescale of at most 1000 yr is needed to reconcile model prediction with observations. This rate is at least two orders of magnitude higher than the fastest destruction rate included in chemical databases. A range of potential physical mechanisms to explain the low observed CO2abundances are discussed.

Conclusions.We conclude that transport processes in disks can have profound effects on the abundances of species in the inner disk such as CO2. The discrepancy between our model and observations either suggests frequent shocks in the inner 10 AU that destroy CO2, or that the abundant midplane CO2is hidden from our view by an optically thick column of low abundance CO2due to strong UV and/or X-rays in the surface layers. Modelling and observations of other molecules, such as CH4or NH3, can give further handles on the rate of mass transport.
Une analyse interdisciplinaire des vulnérabilités socioenvironnementales : le cas de falaises côtières urbanisées en Méditerranée
Authors: Claeys Cécilia , Giuliano Jérémy , Tepongning Megnifo Hervé , Fissier Laurent , Rouadjia Anna , Lizée Cécile , Geneys Cyril , Marçot Nathalie
Published: December 2017

Cet article présente une recherche interdisciplinaire associant sociologie et géologie. L'analyse porte sur la vulnérabilité urbaine vis-à-vis de l'érosion des falaises côtières. Le terrain d'étude est la commune de Carry-le-Rouet dont le littoral est constitué de falaises calcaires associées parfois à de la calcarénite, en alternance avec des niveaux sableux et argileux moins consolidés, d'une hauteur maximale de 40 m. L'analyse révèle que certains des quartiers les plus luxueux de la commune sont les plus exposés au risque d'érosion, échappant au « classique » cumul des vulnérabilités sociales et environnementales. Les riverains n'ignorent pas le risque, mais, attachés à une culture anthropocentrée et techniciste, ils occultent leur trajectoire de vulnérabilité. En outre, la capacité d'action de ces populations aisées leur permet de capter à leur profit les bénéfices de la solidarité territoriale, par l'obtention de travaux de renforcement financés par la puissance publique, tout en revendiquant un entre-soi socialement et ethniquement sélectif.