bluuebunny/crossref_metadata_2025 huggingface dataset:
Linking in silico MS/MS spectra with chemistry data to improve identification of unknowns
Authors: McEachran Andrew D. , Balabin Ilya , Cathey Tommy , Transue Thomas R. , Al-Ghoul Hussein , Grulke Chris , Sobus Jon R. , Williams Antony J.
Published: August 2019

Confident identification of unknown chemicals in high resolution mass spectrometry (HRMS) screening studies requires cohesive workflows and complementary data, tools, and software. Chemistry databases, screening libraries, and chemical metadata have become fixtures in identification workflows. To increase confidence in compound identifications, the use of structural fragmentation data collected via tandem mass spectrometry (MS/MS or MS2) is vital. However, the availability of empirically collected MS/MS data for identification of unknowns is limited. Researchers have therefore turned to in silico generation of MS/MS data for use in HRMS-based screening studies. This paper describes the generation en masse of predicted MS/MS spectra for the entirety of the US EPA’s DSSTox database using competitive fragmentation modelling and a freely available open source tool, CFM-ID. The generated dataset comprises predicted MS/MS spectra for ~700,000 structures, and mappings between predicted spectra, structures, associated substances, and chemical metadata. Together, these resources facilitate improved compound identifications in HRMS screening studies. These data are accessible via an SQL database, a comma-separated export file (.csv), and EPA’s CompTox Chemicals Dashboard.
TGF-β signaling promotes tube-structure-forming growth in pancreatic duct adenocarcinoma
Authors: Yamaguchi Takashi , Ikehara Sanae , Akimoto Yoshihiro , Nakanishi Hayao , Kume Masahiko , Yamamoto Kazuo , Ohara Osamu , Ikehara Yuzuru
Published: August 2019

Tube-forming growth is an essential histological feature of pancreatic duct adenocarcinoma (PDAC) and of the pancreatic duct epithelium; nevertheless, the nature of the signals that start to form the tubular structures remains unknown. Here, we showed the clonal growth of PDAC cell lines in a three-dimensional (3D) culture experiment that modeled the clonal growth of PDAC. At the beginning of this study, we isolated the sphere- and tube-forming clones from established mouse pancreatic cancer cell lines via limiting dilution culture using collagen gel. Compared with cells in spherical structures, the cells in the formed tubes exhibited a lower CK19 expression in 3D culture and in the tumor that grew in the abdominal cavity of nude mice. Conversely, the expression of the transforming growth factor β (TGF-β)-signaling target mRNAs was higher in the formed tube vs the spherical structures, suggesting that TGF-β signaling is more active in the tube-forming process than the sphere-forming process. Treatment of sphere-forming clones with TGF-β1 induced tube-forming growth, upregulated the TGF-β-signaling target mRNAs, and yielded electron microscopic findings of a fading epithelial phenotype. In contrast, the elimination of TGF-β-signaling activation by treatment with inhibitors diminished the tube-forming growth and suppressed the expression of the TGF-β-signaling target mRNAs. Moreover, upregulation of the Fn1, Mmp2, and Snai1 mRNAs, which are hallmarks of tube-forming growth in PDAC, was demonstrated in a mouse model of carcinogenesis showing rapid progression because of the aggressive invasion of tube-forming cancer. Our study suggests that the tube-forming growth of PDAC relies on the activation of TGF-β signaling and highlights the importance of the formation of tube structures.
Enhanced Depth Navigation Through Augmented Reality Depth Mapping in Patients with Low Vision
Authors: Angelopoulos Anastasios Nikolas , Ameri Hossein , Mitra Debbie , Humayun Mark
Published: August 2019

Patients diagnosed with Retinitis Pigmentosa (RP) show, in the advanced stage of the disease, severely restricted peripheral vision causing poor mobility and decline in quality of life. This vision loss causes difficulty identifying obstacles and their relative distances. Thus, RP patients use mobility aids such as canes to navigate, especially in dark environments. A number of high-tech visual aids using virtual reality (VR) and sensory substitution have been developed to support or supplant traditional visual aids. These have not achieved widespread use because they are difficult to use or block off residual vision. This paper presents a unique depth to high-contrast pseudocolor mapping overlay developed and tested on a Microsoft Hololens 1 as a low vision aid for RP patients. A single-masked and randomized trial of the AR pseudocolor low vision aid to evaluate real world mobility and near obstacle avoidance was conducted consisting of 10 RP subjects. An FDA-validated functional obstacle course and a custom-made grasping setup were used. The use of the AR visual aid reduced collisions by 50% in mobility testing (p = 0.02), and by 70% in grasp testing (p = 0.03). This paper introduces a new technique, the pseudocolor wireframe, and reports the first significant statistics showing improvements for the population of RP patients with mobility and grasp.
Unstable, Super Critical CO2–Water Displacement in Fine Grained Porous Media under Geologic Carbon Sequestration Conditions
Authors: Gooya R. , Silvestri A. , Moaddel A. , Andersson M. P. , Stipp S. L. S. , Sørensen H. O.
Published: August 2019

In this study we investigated fluid displacement water with supercritical (sc) CO2 in chalk under conditions close to those used for geologic CO2 sequestration (GCS), to answer two main questions: How much volume is available for scCO2 injection? And what is the main mechanism of displacement over a range of temperatures? Characterization of immiscible scCO2 displacement, at the pore scale in the complex microstructure in chalk reservoirs, offers a pathway to better understand the macroscopic processes at the continuum scale. Fluid behavior was simulated by solving the Navier-Stokes equations, using finite-volume methods within a pore network. The pore network was extracted from a high resolution 3D image of chalk, obtained using X-ray nanotomography. Viscous fingering dominates scCO2 infiltration and pores remain only partially saturated. The unstable front, developed with high capillary number, causes filling of pores aligned with the flow direction, reaching a maximum of 70% scCO2 saturation. The saturation rate increases with temperature but the final saturation state is the same for all investigated temperatures. The higher the saturation rate, the higher the dynamic capillary pressure coefficient. A higher dynamic capillary pressure coefficient indicates that scCO2 needs more time to reach capillary equilibrium in the porous medium.
Metabolites of type I, II, III, and IV collagen may serve as markers of disease activity in axial spondyloarthritis
Authors: Hušáková Markéta , Bay-Jensen Anne-C. , Forejtová Šárka , Zegzulková Kateřina , Tomčík Michal , Gregová Monika , Bubová Kristýna , Hořínková Jana , Gatterová Jindra , Pavelka Karel , Siebuhr Anne Sofie
Published: August 2019

Local inflammation in axial spondyloarthritis (axSpA) leads to the release of collagen metabolites from the disease-affected tissue. We investigated whether collagen metabolites were associated with disease activity and could distinguish non-radiographic(nr)-axSpA from ankylosing spondylitis (AS). A total of 193 axSpA patients (nr-axSpA, n = 121 and AS, n = 72) and asymptomatic controls (n = 100) were included. Serum levels of metalloproteinase (MMP)-degraded collagen type I (C1M), type II (C2M), type III (C3M) and type IV (C4M2) were quantified by enzyme-linked immunosorbent assay (ELISA). All metabolites were higher in axSpA than in controls (all p < 0.001). Serum levels of C1M, C3M, and C4M2 were increased in AS compared to nr-axSpA (43.4 ng/mL vs. 34.6; p < 0.001, 15.4 vs. 12.8; p = 0.001, and 27.8 vs. 22.4; p < 0.001). The best metabolite to differentiate between axSpA and controls was C3M (AUC 0.95; specificity 92.0, sensitivity 83.4). C1M correlated with ASDAS-CRP in nr-axSpA (ρ = 0.37; p < 0.001) and AS (ρ = 0.57; p < 0.001). C1M, C3M, and C4M2 were associated with ASDAS-CRP in AS and nr-axSpA after adjustment for age, gender, and disease duration. Serum levels of collagen metabolites were significantly higher in AS and nr-axSpA than in controls. Moreover, the present study indicates that collagen metabolites reflect disease activity and are useful biomarkers of axSpA.
Chain length-dependent luminescence in acceptor-doped conjugated polymers
Authors: Scheer Pieter van der , Laar Ties van de , Sprakel Joris
Published: August 2019

Semiconducting polymers doped with a minority fraction of energy transfer acceptors feature a sensitive coupling between chain conformation and fluorescence emission, that can be harnessed for advanced solution-based molecular sensing and diagnostics. While it is known that chain length strongly affects chain conformation, and its response to external cues, the effects of chain length on the emission patterns in chromophore-doped conjugated polymers remains incompletely understood. In this paper, we explore chain-length dependent emission in two different acceptor-doped polyfluorenes. We show how the binomial distribution of acceptor incorporation, during the probabilistic polycondensation reaction, creates a strong chain-length dependency in the optical properties of this class of luminescent polymers. In addition, we also find that the intrachain exciton migration rate is chain-length dependent, giving rise to additional complexity. Both effects combined, make for the need to develop sensoric conjugated polymers of improved monodispersity and chemical homogeneity, to improve the accuracy of conjugated polymer based diagnostic approaches.
Engineering genetically encoded FRET-based nanosensors for real time display of arsenic (As3+) dynamics in living cells
Authors: Soleja Neha , Manzoor Ovais , Khan Parvez , Mohsin Mohd.
Published: August 2019

Arsenic poisoning has been a major concern that causes severe toxicological damages. Therefore, intricate and inclusive understanding of arsenic flux rates is required to ascertain the cellular concentration and establish the carcinogenetic mechanism of this toxicant at real time. The lack of sufficiently sensitive sensing systems has hampered research in this area. In this study, we constructed a fluorescent resonance energy transfer (FRET)-based nanosensor, named SenALiB (Sensor for Arsenic Linked Blackfoot disease) which contains a metalloregulatory arsenic-binding protein (ArsR) as the As3+ sensing element inserted between the FRET pair enhanced cyan fluorescent protein (ECFP) and Venus. SenALiB takes advantage of the ratiometic FRET readout which measures arsenic with high specificity and selectivity. SenALiB offers rapid detection response, is stable to pH changes and provides highly accurate, real-time optical readout in cell-based assays. SenALiB-676n with a binding constant (Kd) of 0.676 × 10−6 M is the most efficient affinity mutant and can be a versatile tool for dynamic measurement of arsenic concentration in both prokaryotes and eukaryotes in vivo in a non-invasive manner.
Differential gene expression analysis reveals novel genes and pathways in pediatric septic shock patients
Authors: Mohammed Akram , Cui Yan , Mas Valeria R. , Kamaleswaran Rishikesan
Published: August 2019

Septic shock is a devastating health condition caused by uncontrolled sepsis. Advancements in high-throughput sequencing techniques have increased the number of potential genetic biomarkers under review. Multiple genetic markers and functional pathways play a part in development and progression of pediatric septic shock. We identified 53 differentially expressed pediatric septic shock biomarkers using gene expression data sampled from 181 patients admitted to the pediatric intensive care unit within the first 24 hours of their admission. The gene expression signatures showed discriminatory power between pediatric septic shock survivors and nonsurvivor types. Using functional enrichment analysis of differentially expressed genes, we validated the known genes and pathways in septic shock and identified the unexplored septic shock-related genes and functional groups. Differential gene expression analysis revealed the genes involved in the immune response, chemokine-mediated signaling, neutrophil chemotaxis, and chemokine activity and distinguished the septic shock survivor from non-survivor. The identification of the septic shock gene biomarkers may facilitate in septic shock diagnosis, treatment, and prognosis.
N-Substituted Auxiliaries for Aerobic Dehydrogenation of Tetrahydro-isoquinoline: A Theory-Guided Photo-Catalytic Design
Authors: Jayaraj Savithra , Badu-Tawiah Abraham K.
Published: August 2019

Visible-light mediated aerobic dehydrogenation of N-heterocyclic compounds is a reaction with enormous potential for application. Herein, we report the first complete aerobic dehydrogenation pathway to large-scale production of isoquinolines. The discovery of this visible light photoredox reaction was enabled through the combination of mathematical simulations and real-time quantitative mass spectrometry screening. The theoretical calculations showed that hyper-conjugation, the main underlying factor hindering the aerobic oxidation of tetrahydroisoquinolines, is relieved both by π- and σ-donating substituents. This mechanistic insight provided a novel photocatalytic route based on N-substituted auxiliaries that facilitated the conversion of tetrahydroisoquinolines into the corresponding isoquinolines in just three simple steps (yield 71.7% in bulk-solution phase), using unmodified Ru(bpy)3Cl2 photocatalyst, sun energy, atmospheric O2, and at ambient temperature.
Independent effect of physical activity and resting heart rate on the incidence of atrial fibrillation in the general population
Authors: Choi Yeon Woo , Park Minsu , Lim Young-Hyo , Myung Jisun , Kim Byung Sik , Lee Yonggu , Shin Jeong-Hun , Park Hwan-Cheol , Shin Jinho , Kim Chun Ki , Park Jin-Kyu
Published: August 2019

While physical activity (PA) may influence resting heart rate (RHR), and a low RHR may be a risk factor for atrial fibrillation (AF), controversy exists regarding the association between PA and development of AF. Using data from a Korean, prospective population cohort, we investigated the independent effect of PA and RHR on the incidence of AF in the general population. A total of 8,811 participants aged 40–69 years were analyzed. Total PA assessed based on questionnaires was divided into quartiles, with the lowest to the highest being Q1, Q2, Q3, and Q4. During a median follow-up of 139 months, AF developed in 167 participants (1.9%). Q3 of total PA was associated with a significantly lower risk of AF than Q1 even after adjusting for RHR as a covariate, but Q4 was not. The risk of AF was higher in participants with RHR < 60 bpm than in those with RHR 70–85 bpm, and the significance persisted after adjusting for PA as a covariate. This study showed that a moderate amount of total PA was associated with a lower risk of incident AF independent of RHR and that low RHR was an independent risk factor for AF in the general Korean population.
NOVA1 induction by inflammation and NOVA1 suppression by epigenetic regulation in head and neck squamous cell carcinoma
Authors: Kim Eun Kyung , Cho Yoon Ah , Seo Mi-kyoung , Ryu Hyunmi , Cho Byoung Chul , Koh Yoon Woo , Yoon Sun Och
Published: August 2019

Neuro-oncological ventral antigen 1 (NOVA1) is known as a neuron-specific pre-mRNA binding splicing factor. Previously, it was shown to be highly upregulated in T lymphocytes, as well as fibroblasts/stromal spindle cells, in tertiary lymphoid tissues formed by the benign immune-inflammatory process, while it was frequently downregulated in tumor cells and other cells within the tumor microenvironment. Here, we sought to identify the mechanisms of NOVA1 modulation in head and neck squamous cell carcinoma (HNSCC). NOVA1 was induced by inflammatory-immune signals within the tumor microenvironment and was suppressed by epigenetic dysregulation, such as that with miR-146. We found attenuated expression of NOVA1 to be associated with non-oropharynx sites such as oral cavity, hypopharynx, and larynx, human papilloma virus (HPV)-negative SCC defined by immunohistochemistry for p16INK4a expression, fewer tumor infiltrating lymphocytes, and poor patient outcomes. Moreover, changes were discovered in epithelial mesenchymal transition-associated markers according to NOVA1 status. This study provides some insights to the underlying mechanism of NOVA1 regulation and suggests that NOVA1 may serve as a prognostic biomarker and potential therapeutic target for HNSCC in the future.
Effect of flavor on neuronal responses of the hypothalamus and ventral tegmental area
Authors: van Opstal A. M. , van den Berg-Huysmans A. A. , Hoeksma M. , Blonk C. , Pijl H. , Rombouts S. A. R. B. , van der Grond J.
Published: August 2019

Although it is well known that food intake is affected by the palatability of food, the actual effect of flavoring on regulation of energy-homeostasis and reward perception by the brain, remains unclear. We investigated the effect of ethyl-butyrate (EB), a common non-caloric food flavoring, on the blood oxygen level dependent (BOLD) response in the hypothalamus (important in regulating energy homeostasis) and ventral tegmental area (VTA; important in reward processes). The 16 study participants (18–25 years, BMI 20–23 kg/m2) drank four study stimuli on separate visits using a crossover design during an fMRI setup in a randomized order. The stimuli were; plain water, water with EB, glucose solution (50gram/300 ml) and glucose solution with EB. BOLD responses to ingestion of the stimuli were determined in the hypothalamus and VTA as a measure of changes in neuronal activity after ingestion. In the hypothalamus and VTA, glucose had a significant effect on the BOLD response but EB flavoring did not. Glucose with and without EB led to similar decrease in hypothalamic BOLD response and glucose with EB resulted in a decrease in VTA BOLD response. Our results suggest that the changes in neuronal activity in the hypothalamus are mainly driven by energy ingestion and EB does not influence the hypothalamic response. Significant changes in VTA neuronal activity are elicited by energy combined with flavor.
A QSP Model for Predicting Clinical Responses to Monotherapy, Combination and Sequential Therapy Following CTLA-4, PD-1, and PD-L1 Checkpoint Blockade
Authors: Milberg Oleg , Gong Chang , Jafarnejad Mohammad , Bartelink Imke H. , Wang Bing , Vicini Paolo , Narwal Rajesh , Roskos Lorin , Popel Aleksander S.
Published: August 2019

Over the past decade, several immunotherapies have been approved for the treatment of melanoma. The most prominent of these are the immune checkpoint inhibitors, which are antibodies that block the inhibitory effects on the immune system by checkpoint receptors, such as CTLA-4, PD-1 and PD-L1. Preclinically, blocking these receptors has led to increased activation and proliferation of effector cells following stimulation and antigen recognition, and subsequently, more effective elimination of cancer cells. Translation from preclinical to clinical outcomes in solid tumors has shown the existence of a wide diversity of individual patient responses, linked to several patient-specific parameters. We developed a quantitative systems pharmacology (QSP) model that looks at the mentioned checkpoint blockade therapies administered as mono-, combo- and sequential therapies, to show how different combinations of specific patient parameters defined within physiological ranges distinguish different types of virtual patient responders to these therapies for melanoma. Further validation by fitting and subsequent simulations of virtual clinical trials mimicking actual patient trials demonstrated that the model can capture a wide variety of tumor dynamics that are observed in the clinic and can predict median clinical responses. Our aim here is to present a QSP model for combination immunotherapy specific to melanoma.
Functions of hydroxyapatite in fabricating N-doped carbon for excellent catalysts and supercapacitors
Authors: Chu Minzhe , Zhai Yingying , Shang Ningzhao , Zhang Xiaoyu , Wang Chun , Zhang Yunrui , Wang Haijun , Gao Yongjun
Published: August 2019

N-doped carbon derived from 1,10-phenanthroline with hydroxyapatite (HAP) as template exhibits excellent catalytic activity for the oxidative coupling of amines to imines and remarkable electrochemical performance for supercapacitors.
Construction of a hollow structure in La0.9K0.1CoO3−δ nanofibers via grain size control by Sr substitution with an enhanced catalytic performance for soot removal
Authors: Fang Fan , Zhao Peng , Feng Nengjie , Chen Chong , Li Xue , Liu Geng , Wan Hui , Guan Guofeng
Published: August 2019

The hollow structure is formed by Sr2+ doping in La0.9K0.1CoO3−δ nanofibers for decreasing the grain size, which can improve the contact efficiency of soot–catalyst–gas as well as the intrinsic activity, responsible for the enhancement in activity.
[3 + 2] cycloaddition of azido-bridged molybdenum(ii) complex with nitriles and alkynes
Authors: Chen You-Xuan , Yang Hsueh-Hui , Lin Yu-Liang , Hou Ji-Kuan , Chu Yong-Jui , Liu Fu-Chen , Lee Gene-Hsiang
Published: August 2019

[3 + 2] cycloaddition products of bridging tetrazolato- and triazolato-complexes were isolated from the reactions of [N(CH3)4][(μ1,1-N3)3{Mo(η3-C3H5)(CO)2}2] with various nitriles and alkynes.
Influence of different sequences of l-proline dipeptide derivatives in the pendants on the helix of poly(phenylacetylene)s and their enantioseparation properties
Authors: Zhou Yanli , Zhang Chunhong , Zhou Zhengjin , Zhu Ruiqi , Liu Lijia , Bai Jianwei , Dong Hongxing , Satoh Toshifumi , Okamoto Yoshio
Published: August 2019

Novel helical poly(phenylacetylene)s bearing different sequences of l-proline dipeptide derivative pendants were prepared and used as CSPs in HPLC for enantioseparation.
Optimization and characterization of magnetite–reduced graphene oxide nanocomposites for demulsification of crude oil in water emulsion
Authors: Wai Mun Mun , Khe Cheng Seong , Yau Xin Hui , Liu Wei Wen , Sokkalingam Rajalingam , Jumbri Khairulazhar , Lwin Nilar
Published: August 2019

Magnetite reduced graphene oxide were synthesized for separation of crude oil in water emulsion.
A graphene-based hybrid material with quantum bits prepared by the double Langmuir–Schaefer method
Authors: Hrubý Jakub , Santana Vinicius T. , Kostiuk Dmytro , Bouček Martin , Lenz Samuel , Kern Michal , Šiffalovič Peter , van Slageren Joris , Neugebauer Petr
Published: August 2019

Graphene-based hybrid material with array of copper(ii)-based quantum bits was prepared by a wet-chemistry protocol and characterised by HF-ESR, XPS, Raman, and AFM.
Single-phase Ni5P4–copper foam superhydrophilic and aerophobic core–shell nanostructures for efficient hydrogen evolution reaction
Authors: Das Manisha , Jena Nityasagar , Purkait Taniya , Kamboj Navpreet , De Sarkar Abir , Dey Ramendra Sundar
Published: August 2019

A facile route for electrochemical synthesis of single-phase Ni5P4 on copper foam results in a core-shell nanostructures catalyst for the efficient generation of hydrogen with a very less overpotential and excellent stability at high current density.
Understanding the role of functional groups of thiolate ligands in electrochemical CO2 reduction over Au(111) from first-principles
Authors: Li Fuhua , Tang Qing
Published: August 2019

The functional groups of thiolates strongly affect the catalytic activity and product selectivity of CO2 electroreduction on Au(111).
A borate decorated anion-immobilized solid polymer electrolyte for dendrite-free, long-life Li metal batteries
Authors: Ma Cheng , Feng Yiming , Xing Fangzhou , Zhou Lin , Yang Ying , Xia Qingbing , Zhou Liangjun , Zhang Lijun , Chen Libao , Ivey Douglas G. , Sadoway Donald R. , Wei Weifeng
Published: August 2019

A borate decorated anion-immobilized solid polymer electrolyte effectively integrates high ionic conductivity, high Li+ transference number and reasonably mechanical integrity, enabling long-term cycling stability for dendrite-free lithium metal batteries.
Stiff micelle-crosslinked hyaluronate hydrogels with low swelling for potential cartilage repair
Authors: Ren Penggang , Zhang Hua , Dai Zhong , Ren Fang , Wu Yidong , Hou Ruixia , Zhu Yabin , Fu Jun
Published: August 2019

Pluronic F127 diacrylate (F127DA) micelle-crosslinked methacrylated hyaluronic acid (MeHA) hydrogel with low-swelling and strong compressive properties was successfully synthesized for the regeneration of cartilages in vivo.
New experimental study on the DC flashover voltage of polymer insulators: combined effect of surface charges and air humidity
Authors: Amer Mohammed , Laninga Jeff , McDermid William , Swatek David R. , Kordi Behzad
Published: August 2019

This research provides conclusions that can partially cover the lack of knowledge related to the effects of ambient atmospheric conditions on DC electric power transportation. Two polymer insulating materials are used for completing this research study. Inside a climate chamber, the relative humidity is controlled and adjusted from 20% to 80% RH. Then, the samples are charged with positive or negative charges by applying to the corona‐generating ring of needles. The surface potential is measured using an electrostatic voltmeter and is converted into surface charge density later by applying the probe response matrix method. The pre‐charged samples are then stressed with high‐voltage negative or positive DC values inside the climate chamber over a range of controlled values of the surrounding air humidity until flashover takes place. The space charges, which can drift in the air gap to reach the solid surface, are highly affected by the level of the relative humidity of the surrounding air. Also, increasing humidity results in a reduction of the DC flashover inception voltage and a shorter time to flashover regardless of the voltage polarity. Moreover, the positive or negative flashover inception voltage of both materials increases with pre‐deposited negative charges while it decreases with pre‐deposited positive charges.
mixed‐sensitivity robust control design for damping low‐frequency oscillations with DFIG wind power generation
Authors: Isbeih Younes J. , El Moursi Mohamed Shawky , Xiao Weidong , El‐Saadany Ehab
Published: August 2019

This study presents a mixed‐sensitivity robust control design to improve the overall damping performance of low‐frequency oscillations for power systems with doubly fed induction generator‐based (DFIG) wind power generation. The supplementary damping controller is designed in the linear matrix inequality framework which allows the placement of the closed‐loop poles inside a pre‐defined region for improved stability. The damping signal is implemented at the reactive power modulation of the rotor‐side converter of the DFIG wind turbine (DFIG‐WT). The damping contribution of the power oscillator damper is compared with that provided by the power system stabiliser (PSS) of the synchronous generator (SG). State‐space system analysis and time‐domain simulations show the capability of DFIG‐WT to enhance the overall damping of the oscillatory modes even if PSSs are not installed at SG s. Also, the designed controller shows a robust performance to wind speed variations. The performance evaluation is based on the revised two‐area four machines system and the revised New England 39‐bus system.
Restoration duration estimation applying generally distributed transition stochastic Petri nets considering the switching failure of breakers
Authors: Abbaszadeh Amir , Abedi Mehrdad , Doustmohammadi Ali , Ebrahimi Mohammad Reza
Published: August 2019

Once blackouts occur the system operators should re‐energise the affected system in the shortest time. To attain this, restoration plans should be developed beforehand. A deliberate restoration plan considers the supply duration of the cranking power to non‐black‐start units (NBSUs), besides the static and dynamic constraints of the power system. Hence, there should be a method to estimate the restoration duration of NBSUs considering the failure in breakers operating mechanism and the stochastic nature of restoration actions. Accordingly, in this study, generally distributed transition stochastic Petri net is employed to calculate the supply duration of NBSUs, critical loads and the execution time of restoration actions. This is significant because the planners can validate their restoration plans from the NBSUs critical times’ point of view or determine energisation time of critical loads. The proposed method has been applied in three test cases, two of these are used for benchmarking, and the other one is a part of Iran bulk power system, which includes a real black‐start test. The results show the effectiveness of the method in estimating the restoration duration.
Cloud computing in the smart grid context: an application to aid fault location in distribution systems concerning the multiple estimation problem
Authors: de Sousa Jeovane V. , Reche Evandro A. , Coury Denis V. , Fernandes Ricardo A.S.
Published: August 2019

Cloud computing has been envisioned as the main technology capable of integrating and managing many systems in a smart grid (SG). Thus, this research aims to develop a cloud computing infrastructure to store and manipulate smart distribution system data. To do this, extensible architecture with essential services was proposed to be integrated into an advanced metering infrastructure to host new applications in smart distribution systems. Based on this proposition, a cloud computing platform was developed using open source tools. A new application to reduce multiple estimation for fault location in radial distribution systems using data mining techniques over smart meter data was implemented. An optimised version of the data mining tool known as DAMICORE (DAta MIning of COde REpositories) was implemented as an extension to the proposed architecture basic services. The new cloud application was tested using hundreds of fault simulations on a test feeder and was able to reduce multiple estimation by more than 90% in the simulated fault cases. The results show that the proposed cloud computing architecture and infrastructure enable new smart distribution system applications, contributing to the development of SGs and diffusion of cloud computing in this context.
Assessment of PMU‐based wide‐area angle criterion for fault detection in microgrid
Authors: Sharma Nikhil Kumar , Samantaray Subhransu Ranjan
Published: August 2019

The penetration of distributed generation in the power distribution system has increased significantly in recent years, bringing serious protection challenges. Hence, it is mandated to develop effective and reliable fault detection scheme for present‐day microgrid environment. This study presents a phasor measurement unit‐based (PMU) wide‐area phase angle criterion for building a protection system for the microgrid. The absolute value of the rate of change of voltage phase angle difference between the point of common coupling and the bus closest to the fault point is utilised for fault detection in grid connected as well as in the islanded modes of operation. C37.118.1 complied PMUs are employed at the appropriate locations for accurate and faithful measurement of voltage phase angle and the rate of angle difference (RAD) for detecting faulted conditions. PMUs are connected to phasor data concentrator, which receives the time synchronised phasor data and acts as a centralised processing unit. The proposed protection index has been extensively validated on MATLAB/Simulink environment as well as the real‐time digital simulator with external PMUs. The test results show that the proposed RAD is a potential candidate for providing effective fault detection measure for microgrid including large variations in operating conditions.
New method for calculating voltage dip/swell types based on six‐dimensional vectors and Euclidean distance
Authors: Wang Ying , Yu Hua‐Xi , Xiao Xian‐Yong , Ma Ming , Zhou Yuan
Published: August 2019

The type of voltage dip or swell is an important information for utilities and customers to reduce the negative impact by voltage dip/swell. This study proposes a method to calculate the voltage dip/swell type, by transforming the three‐phase voltage vector to a six‐dimensional vector, generating a whole‐range database and calculating the Euclidean distances between the measured voltage dip/swell and the synthetic voltage vectors in database. The voltage dip/swell type is determined by the minimum Euclidean distance. The accuracy of the proposed method is verified by the tens of thousands of synthetic dips/swells and 203 sets of measured voltage dips/swells. Extensive comparison has been done, including the comparison between the proposed method and the typical algorithms. It is proved that the proposed method can overcome the shortcomings of the typical algorithms and shows good performance in two scenarios. Finally, a practical dip type chart is proposed for evaluating the event type quickly for the engineers who are interested in quick evaluation of the potential dip type.
Improved neural network classification of hyperspectral imagery using weighted genetic algorithm and hierarchical segmentation
Authors: Akbari Davood
Published: August 2019

This study proposes a modified spectral–spatial classification approach for improving the spectral–spatial classification of hyperspectral images. The spatial information is obtained by an enhanced marker‐based hierarchical segmentation (MHS) algorithm. The weighted genetic (WG) algorithm is first employed to obtain the subspace of hyperspectral data. The obtained features are then fed into the multi‐layer perceptron (MLP) neural network classification algorithm. Afterwards, the MHS algorithm is applied in order to increase the accuracy of less‐accurately classified land‐cover types. In the proposed approach, namely MLP‐MHS, the markers are extracted from the classification maps obtained by MLP and support vector machine classifiers. Experiments on two benchmark hyperspectral datasets, Pavia University and Berlin, validate the soundness of the proposed approach compared to the MLP and the original MHS algorithms.
Appearance model update based on online learning and soft‐biometrics traits for people re‐identification in multi‐camera environments
Authors: Moctezuma Daniela , Tellez Eric S. , Miranda‐Jiménez Sabino , Graff Mario
Published: August 2019

Intelligent surveillance systems in multi‐camera environments pose a hard‐open problem for computer vision. The way the people look changes inside and also among cameras, so people re‐identification task can be largely improved collecting data about people already identified and take advantage of it as time advances in surveillance video. Furthermore, a camera change or a slight change in the objective traits may require the complete re‐formulation of the appearance models. In this paper, we propose several heuristics for updating the appearance model in a multi‐camera surveillance environment. Through these heuristics, the subject's appearance model is updated across different time and environmental conditions. The update process is carried out primarily in three different aspects: 1) based on time lapses, 2) based on the change of camera, and 3) based on the automatic selection of the most representative samples selected through decision functions of the classifier. The proposed system focuses on video surveillance environments, that is, the objective is to identify an individual across the set of cameras in the surveillance area, the comparison considers only those people that share time and space. We used four public benchmarks to test our claims; the results confirm the importance of continuous appearance model's updating.
DDLA: dual deep learning architecture for classification of plant species
Authors: Sundara Sobitha Raj Anubha Pearline , Vajravelu Sathiesh Kumar
Published: August 2019

Plant species recognition is performed using a dual deep learning architecture (DDLA) approach. DDLA consists of MobileNet and DenseNet‐121 architectures. The feature vectors obtained from individual architectures are concatenated to form a final feature vector. The extracted features are then classified using machine learning (ML) classifiers such as linear discriminant analysis, multinomial logistic regression (LR), Naive Bayes, classification and regression tree, k‐nearest neighbour, random forest classifier, bagging classifier and multi‐layer perceptron. The dataset considered in the studies is standard (Flavia, Folio, and Swedish Leaf) and custom collected (Leaf‐12) dataset. The MobileNet and DenseNet‐121 architectures are also used as a feature extractor and a classifier. It is observed that the DDLA architecture with LR classifier produced the highest accuracies of 98.71, 96.38, 99.41, and 99.39% for Flavia, Folio, Swedish leaf, and Leaf‐12 datasets. The observed accuracy for DDLA + LR is higher compared with other approaches (DDLA + ML classifiers, MobileNet + ML classifiers, DenseNet‐121 + ML classifiers, MobileNet + fully connected layer (FCL), DenseNet‐121 + FCL). It is also observed that the DDLA architecture with LR classifier achieves higher accuracy in comparable computation time with other approaches.
Optimal placement of heterogeneous distributed generators in a grid‐connected multi‐energy microgrid under uncertainties
Authors: Li Zhengmao , Xu Yan , Fang Sidun , Mazzoni Stefano
Published: August 2019

The multi‐energy microgrid (MEMG) comprises heterogeneous distributed generators (DGs) such as wind turbines, diesel generators, combined cooling, heat and power plants etc. Proper placement of these DGs is critical for the system energy efficiency and network reliability performance. This study proposes a two‐stage coordinated method for optimally placing heterogeneous DGs in an MEMG project considering the uncertainties from renewable energy sources (RESs). Apart from optimising the traditional DG size and location, this method considers the optimal DG type and investment year simultaneously by maximising the project net present value (NPV), which consists of investment costs and operation costs. The whole problem is modelled as a two‐stage coordinated stochastic optimisation model, where the long‐term DG investment is determined at the first stage and operation decisions are determined at the second stage. The proposed method is verified on a test MEMG system. The simulation results show that its NPV is positive, which means the method is effective and should be implemented. Compared with the conventional DG placement approaches, the proposed method is more robust against the RES uncertainties and can better coordinate the heterogeneous energies with higher dispatch flexibility and economic profits.
Precision 500/√3 kV three‐stage VT with double excitation
Authors: Yin Xiaodong , Liu Hao , Lan Lei , Zhou Feng , Lei Min , Jiang Chunyang
Published: August 2019

To develop the highest standard for high‐voltage ratio at power frequency, this study describes a three‐stage voltage transformer (VT) with high‐ and low‐voltage double excitation. In this high‐voltage VT, all primary windings are wound as a ‘pyramid’ structure, making it work at higher‐voltage possible. Moreover, the two high excitation and ratio coils are located as vertically symmetrical distribution, good for solving the insulation problem between two primary windings. On the basis of this scheme, a precision 500/√3 kV three‐stage VT has been developed. Calibration based on ‘series summation’ indicates that in the range of 20–120% rated voltage, the error of the three‐stage VT is as follows: (−17.2 to + 7.1) × 10−6 for the ratio error and −5.1 to −1.3 µrad for the phase error, which reaches accuracy class 0.002. Moreover, the uncertainty of this three‐stage VT is 8.7 × 10−6 for ratio and 8.7 µrad for phase (k = 2).
Enhanced electrocaloric effect in a Si-doped PbZr0.95Ti0.05O3 film deposited on FTO substrate
Authors: Wang Jinxin , Jiang Guicheng , Huang Weicheng , Liu Danqing , Yang Bin , Cao Wenwu
Published: August 2019

Materials with an electrocaloric effect (ECE) have been extensively studied for their cooling applications. Most ECE films are oriented and are difficult to integrate into industrial production processes. Here, an ECE (ΔS = 4.48 J K−1 kg−1 and ΔT = 6.4 °C at ΔE = 390 kV cm−1) is obtained in an unoriented PbZr0.95Ti0.05O3 (PZT) film fabricated on an FTO substrate using an improved sol-gel method. To improve the ECE, Si-doped PZT films with 1–4 mol. % of Si are deposited. X-ray diffraction and X-ray photoelectron spectroscopy results confirm that Si was doped into the PZT lattice. The orthorhombic and tetragonal antiferroelectric phases coexist in the PZT/0.01 Si film. A large ECE (ΔS = 5.89 J K−1 kg−1 and ΔT = 8.5 °C at ΔE = 390 kV cm−1) is acquired in the PZT/0.01 Si film, which was measured by an indirect method. This work demonstrates that ECE of unoriented PZT antiferroelectric films on FTO substrates can be improved by a certain amount of Si doping.
Controlling the thermal conductance of silicon nitride membranes at 100 mK temperatures with patterned metal features
Authors: Zhang X. , Duff S. M. , Hilton G. C. , Lowell P. J. , Morgan K. M. , Schmidt D. R. , Ullom J. N.
Published: August 2019

Freestanding micromachined membranes are often used for thermal isolation in electronic devices such as photon sensors. The degree of thermal isolation plays an important role in determining device performance, and so the ability to suppress the thermal conductance of a membrane without increasing its size or decreasing its mechanical strength is of practical importance. We present a simple method that controllably reduces the thermal conductance of silicon nitride membranes by as much as 56% at temperatures near 100 mK. The thermal conductance suppression is achieved by depositing one additional metal layer patterned into islands or rings onto the membrane surface. Complex impedance and noise measurements of superconducting transition-edge sensors fabricated using this technique show that their noise performance is not degraded.
Condensation of ground state from a supercooled phase in the Si(111)-(4 × 1) → (8 × 2)-indium atomic wire system
Authors: Hafke B. , Witte T. , Janoschka D. , Dreher P. , Meyer zu Heringdorf F.-J. , Horn-von Hoegen M.
Published: August 2019

Strong optical irradiation of indium atomic wires on a Si(111) surface causes the nonthermal structural transition from the (8 × 2) reconstructed ground state to an excited (4 × 1) state. The immediate recovery of the system to the ground state is hindered by an energy barrier for the collective motion of the indium atoms along the reaction coordinate from the (4 × 1) to the (8 × 2) state. This metastable, supercooled state can only recover through nucleation of the ground state at defects like adsorbates or step edges. Subsequently, a recovery front propagates with constant velocity across the surface and the (8 × 2) ground state is reinstated. In a combined femtosecond electron diffraction and photoelectron emission microscopy study, we determined—based on the step morphology—a velocity of this recovery front of ∼100 m/s.
An analytical model for predicting residual stresses in multiple layers by plasma cladding process
Authors: Chu Yajie , Hao Benxing , Li Zhenhong , Zhu Jun , He Xiunan
Published: August 2019

An analytical model is developed to predict residual stresses formed during plasma cladding process. This is based on the force and moment balances and misfit strain caused by differential coefficient of thermal expansion (CTE) of substrate and cladding layers during cooling. The model can be implemented by a simple programming. Residual stresses can be predicted from a knowledge of material properties, temperature of substrate and layers and specimen dimensions. Residual stresses are calculated after each layer rather than as a whole. Specific results can be obtained for the distribution of residual stresses within Co-based layers system. The effect of temperature of substrate and layers, the number of layers, the curvature of a composite beam on the residual stresses are discussed. It has been found that the residual stresses decrease with the increase of preheating temperature of substrate and inter-layer temperature of layers. The curvature increase with increasing layer number.
Geminal-based configuration interaction
Authors: Henderson Thomas M. , Scuseria Gustavo E.
Published: August 2019

The antisymmetrized geminal power (AGP) wave function has a long history and considerable conceptual appeal, but in many situations its accuracy is wanting. Here, we consider a form of configuration interaction (CI) based upon the AGP wave function and take advantage of its killing operators to construct an excitation manifold. Our geminal CI reduces to standard single-determinant-based CI in the limit in which AGP reduces to a single determinant. It substantially improves upon AGP in the reduced BCS Hamiltonian, which serves as a prototype for the kinds of strong pairing correlations relevant in Bardeen-Cooper-Schrieffer-style superconductivity. Moreover, our geminal CI naturally generalizes to add correlation to more general geminal-based wave functions than AGP.
Sequence-dependent RNA helix conformational preferences predictably impact tertiary structure formation
Authors: Yesselman Joseph D. , Denny Sarah K. , Bisaria Namita , Herschlag Daniel , Greenleaf William J. , Das Rhiju
Published: August 2019

Significance

Structured RNAs fold into complex tertiary structures to perform critical roles in a multitude of biological functions. Over half the nucleotides in structured RNAs form simple Watson–Crick (WC) double helices, which can then assemble through non-WC interactions into elaborate tertiary structures. Here, we report the serendipitous discovery that sequence changes in WC base pairs impact the energetics of RNA tertiary folding. These observations led to a computational model for helix conformational fluctuations that then blindly predicted the results of thousands of high-throughput experiments with surprisingly high accuracy. Our study reveals that sequence-specific helix structure preferences are needed for understanding RNA folding quantitatively and outlines a route for dissecting the impact of helix conformational fluctuations across general RNA biophysical events.
p120-catenin regulates WNT signaling and EMT in the mouse embryo
Authors: Hernández-Martínez Rocío , Ramkumar Nitya , Anderson Kathryn V.
Published: August 2019

Significance

p120-catenin, an armadillo-repeat protein, regulates the stability of classical cadherins, but its cellular functions in vivo remain unclear. Here, we show that genetic deletion ofp120-cateninin the mouse embryo causes developmental arrest at midgestation with a bifurcation of the posterior body axis. This morphological defect is associated with an expanded primitive streak, p53-dependent cell death, and abnormal mesoderm migration. The expanded primitive streak inp120-cateninmutants is caused by ectopic activation of the canonical WNT signaling pathway, and the bifurcation of the axis is associated with accumulation of mesoderm cells that migrate without direction. The functions of p120-catenin in the early mouse embryo are likely to be important during other developmental epithelial-to-mesenchymal transitions (EMTs) and in tumor metastasis.