bluuebunny/crossref_metadata_2025 huggingface dataset:
Integrating a Path Planner and an Adaptive Motion Controller for Navigation in Dynamic Environments
Authors: Zeng Junjie , Qin Long , Hu Yue , Yin Quanjun , Hu Cong
Published: April 2019

Since an individual approach can hardly navigate robots through complex environments, we present a novel two-level hierarchical framework called JPS-IA3C (Jump Point Search improved Asynchronous Advantage Actor-Critic) in this paper for robot navigation in dynamic environments through continuous controlling signals. Its global planner JPS+ (P) is a variant of JPS (Jump Point Search), which efficiently computes an abstract path of neighboring jump points. These nodes, which are seen as subgoals, completely rid Deep Reinforcement Learning (DRL)-based controllers of notorious local minima. To satisfy the kinetic constraints and be adaptive to changing environments, we propose an improved A3C (IA3C) algorithm to learn the control policies of the robots’ local motion. Moreover, the combination of modified curriculum learning and reward shaping helps IA3C build a novel reward function framework to avoid learning inefficiency because of sparse reward. We additionally strengthen the robots’ temporal reasoning of the environments by a memory-based network. These improvements make the IA3C controller converge faster and become more adaptive to incomplete, noisy information caused by partial observability. Simulated experiments show that compared with existing methods, this JPS-IA3C hierarchy successfully outputs continuous commands to accomplish large-range navigation tasks at shorter paths and less time through reasonable subgoal selection and rational motions.
A Heterogeneous Robotic Swarm for Long-Term Monitoring of Marine Environments
Authors: Lončar Ivan , Babić Anja , Arbanas Barbara , Vasiljević Goran , Petrović Tamara , Bogdan Stjepan , Mišković Nikola
Published: April 2019

This paper describes an underwater acoustic sensor network consisting of a heterogeneous robotic swarm used for long-term monitoring of underwater environments. The swarm consists of a large number of underwater robots acting as sensor nodes with limited movement capabilities, and a few surface robots aiding them in accomplishing underwater monitoring scenarios. Main interactions between two types of robots include underwater sensor deployment and relocation, energy and data exchange, and acoustic localisation aiding. Hardware capabilities of each vehicle are described in detail. Inter-agent communication is split into two layers: surface and underwater communication. Surface communication utilises wireless communication using WiFi routers configured for decentralised routing. Underwater communication mainly uses acoustic communication which, when used within a large swarm, poses a challenging task because of high probability of interference and data loss. The acoustic communication protocol used to prevent these issues is presented in detail. Finally, more complex functionalities of the robotic swarm are presented, including several results from real-life experiments.
A Low-Complexity Resource Allocation Algorithm for Indoor Visible Light Communication Ultra-Dense Networks
Authors: Bai Xiangwei , Li Qing , Tang Yanqun
Published: April 2019

In this paper, a low-complexity multi-cell resource allocation algorithm with a near-optimal system throughput is proposed to resolve the conflict between the high system throughput and low complexity of indoor visible light communication ultra-dense networks (VLC-UDNs). First, by establishing the optimal model of the resource allocation problem in each cell, we concluded that the problem is a convex optimization problem. After this, the analytic formula of the normalized scaling factor of each terminal for resource allocation is derived after reasonable approximate treatment. The resource allocation algorithm is subsequently proposed. Finally, the complexity analysis shows that the proposed algorithm has polynomial complexity, which is lower than the classical optimal inter-point method. The simulation results show that the proposed method achieves a improvement of 57% in performance in terms of the average system throughput and improvement of 67% in performance in terms of the quality of service (QoS) guarantee against the required data rate proportion allocation (RDR-PA) method.
The Pederastic Gaze in Attic Vase-Painting
Authors: Brendle Ross
Published: April 2019

An image on an Attic red-figure kylix attributed to the Antiphon Painter, showing a single youth wrapped tightly in a mantle, represents a type of figure often found in pederastic courting scenes and scenes set in the gymnasium, where male bodies were on display. Subject to the gaze of older men, these youths hide their bodies in their cloaks and exhibit the modesty expected of a boy being courted. While many courting scenes show an erastês approaching a tightly-wrapped erômenos, in this scene, the boy stands alone with no source of modesty-inducing gaze within the image. Combined with the intimate manner in which the user of this cup would experience the image as he held it close to his face to drink, it would appear to the drinker that it is his own gaze that provokes the boy’s modesty. This vase is one of several in which we may see figures within an image reacting to the eroticizing gaze of the user of the vessel. As the drinker drains his cup and sees the boy, the image responds with resistance to the drinker’s gaze. Though seemingly unassuming, these pictures look deliberately outward and declare themselves to an anticipated viewer. The viewer’s interaction with the image is as important to its function as any element within the picture.
Increase Paclitaxel Sensitivity to Better Suppress Serous Epithelial Ovarian Cancer via Ablating Androgen Receptor/Aryl Hydrocarbon Receptor-ABCG2 Axis
Authors: Chung Wei-Min , Ho Yen-Ping , Chang Wei-Chun , Dai Yuan-Chang , Chen Lumin , Hung Yao-Ching , Ma Wen-Lung
Published: April 2019

Background: Epithelial ovarian cancer (EOC) is one of the most lethal gynecological malignancies and presents chemoresistance after chemotherapy treatment. Androgen receptor (AR) has been known to participate in proliferation. Yet the mechanisms of the resistance of this drug and its linkage to the AR remains unclear. Methods: To elucidate AR-related paclitaxel sensitivity, co-IP, luciferase reporter assay and ChIP assay were performed to identify that AR direct-regulated ABCG2 expression under paclitaxel treatment. IHC staining by AR antibody presented higher AR expression in serous-type patients than other types. AR degradation enhancer (ASC-J9) was used to examine paclitaxel-associated and paclitaxel-resistant cytotoxicity in vitro and in vivo. Results: We found AR/aryl hydrocarbon receptor (AhR)-mediates ABCG2 expression and leads to a change in paclitaxel cytotoxicity/sensitivity in EOC serous subtype cell lines. Molecular mechanism study showed that paclitaxel activated AR transactivity and bound to alternative ARE in the ABCG2 proximal promoter region. To identify AR as a potential therapeutic target, the ASC-J9 was used to re-sensitize paclitaxel-resistant EOC tumors upon paclitaxel treatment in vitro and in vivo. Conclusion: The results demonstrated that activation of AR transactivity beyond the androgen-associated biological effect. This novel AR mechanism explains that degradation of AR is the most effective therapeutic strategy for treating AR-positive EOC serous subtype.
Long-Term Storage and Use of Artificially Immobilized Anaerobic Sludge as a Powerful Biocatalyst for Conversion of Various Wastes Including Those Containing Xenobiotics to Biogas
Authors: Senko Olga , Gladchenko Marina , Maslova Olga , Efremenko Elena
Published: April 2019

The aim of this paper is to demonstrate the possibilities of anaerobic sludge cells immobilized into poly(vinyl alcohol) cryogel for the methanogenic conversion of various lignocellulosic waste and other media containing antibiotics (ampicillin, kanamycin, benzylpenicillin) or pesticides (chlorpyrifos or methiocarb and its derivatives). It was established that the immobilized cells of the anaerobic consortium can be stored frozen for at least three years while preserving a high level of metabolic activity. The cells after the long-term storage in an immobilized and frozen state were applied for the methanogenesis of a wide number of wastes, and an increase in both methane yield and methane portion in the produced biogas as compared to the conventionally used suspended anaerobic sludge cells, was ensured. It was shown that the “additional” introduction of bacterial Clostridium acetobutylicum, Pseudomonas sp., Enterococcus faecalis cells (also immobilized using same support) improves characteristics of methanogenesis catalyzed by immobilized anaerobic sludge.
Combined Targeted Omic and Functional Assays Identify Phospholipases A2 that Regulate Docking/Priming in Calcium-Triggered Exocytosis
Authors: Dabral Deepti , Coorssen Jens R
Published: April 2019

The fundamental molecular mechanism underlying the membrane merger steps of regulated exocytosis is highly conserved across cell types. Although involvement of Phospholipase A2 (PLA2) in regulated exocytosis has long been suggested, its function or that of its metabolites—a lyso-phospholipid and a free fatty acid—remain somewhat speculative. Here, using a combined bioinformatics and top-down discovery proteomics approach, coupled with lipidomic analyses, PLA2 were found to be associated with release-ready cortical secretory vesicles (CV) that possess the minimal molecular machinery for docking, Ca2+ sensing and membrane fusion. Tightly coupling the molecular analyses with well-established quantitative fusion assays, we show for the first time that inhibition of a CV surface calcium independent intracellular PLA2 and a luminal secretory PLA2 significantly reduce docking/priming in the late steps of regulated exocytosis, indicating key regulatory roles in the critical step(s) preceding membrane merger.
3D Telomere Structure Analysis to Detect Genomic Instability and Cytogenetic Evolution in Myelodysplastic Syndromes
Authors: Rangel-Pozzo Aline , de Souza Daiane Corrêa , Schmid-Braz Ana Teresa , Azambuja Ana Paula de , Ferraz-Aguiar Thais , Borgonovo Tamara , Mai Sabine
Published: April 2019

The disease course of myelodysplastic syndromes (MDS) features chromosome instability and clonal evolution, leading to the sequential acquisition of novel cytogenetic aberrations and the accumulation of these abnormalities in the bone marrow. Although clonal cytogenetic abnormalities can be detected by conventional cytogenetics in 50% of patients with MDS, such distinguishing patterns are lacking in the other 50%. Despite the increase in the prognostic value of some biomarkers, none of them is specific and able to discriminate between stable and unstable patients that subsequently progress to acute myeloid leukemia. This pilot study aimed to investigate the potential use of the 3D telomere profiling to detect genomic instability in MDS patients with or without clonal cytogenetic evolution. The comparison between different time points in patients with cytogenetic changes showed that in the CD34+ MDS cells, there was a significant decrease in the total number of telomeric signals, the average intensity of signals and the total intensity of telomeres. By contrast, the number of aggregates increased during cytogenetic evolution (p < 0.001). This pattern was observed only for MDS patients with cytogenetic evolution but was absent in patients without cytogenetic changes. In conclusion, we demonstrated that the 3D nuclear telomere organization was significantly altered during the MDS disease course, and may have contributed to cytogenetic clonal evolution.
Ice-Templating for the Elaboration of Oxygen Permeation Asymmetric Tubular Membrane with Radial Oriented Porosity
Authors: Gaudillere Cyril , Garcia-Fayos Julio , Plaza Jorge , Serra José M.
Published: April 2019

An original asymmetric tubular membrane for oxygen production applications was manufactured in a two-step process. A 3 mol% Y2O3 stabilized ZrO2 (3YSZ) porous tubular support was manufactured by the freeze-casting technique, offering a hierarchical and radial-oriented porosity of about 15 µm in width, separated by fully densified walls of about 2 µm thick, suggesting low pressure drop and boosted gas transport. The external surface of the support was successively dip-coated to get a Ce0.8Gd0.2O2−δ – 5mol%Co (CGO-Co) interlayer of 80 µm in thickness and an outer dense layer of La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF) with a thickness of 30 µm. The whole tubular membrane presents both uniform geometric characteristics and microstructure all along its length. Chemical reactivity between each layer was studied by coupling X-Ray Diffraction (XRD) analysis and Energy Dispersive X-Ray spectroscopy (EDX) mapping at each step of the manufacturing process. Cation interdiffusion between different phases was discarded, confirming the compatibility of this tri-layer asymmetric ceramic membrane for oxygen production purposes. For the first time, a freeze-cast tubular membrane has been evaluated for oxygen permeation, exhibiting a value of 0.31 mL·min−1·cm−2 at 1000 °C under air and argon as feed and sweep gases, respectively. Finally, under the same conditions and increasing the oxygen partial pressure to get pure oxygen as feed, the oxygen permeation reached 1.07 mL·min−1·cm−2.
From a Smoking Gun to Spent Fuel: Principled Subsampling Methods for Building Big Language Data Corpora from Monitor Corpora
Authors: Tidwell Jacqueline Hettel
Published: April 2019

With the influence of Big Data culture on qualitative data collection, acquisition, and processing, it is becoming increasingly important that social scientists understand the complexity underlying data collection and the resulting models and analyses. Systematic approaches for creating computationally tractable models need to be employed in order to create representative, specialized reference corpora subsampled from Big Language Data sources. Even more importantly, any such method must be tested and vetted for its reproducibility and consistency in generating a representative model of a particular population in question. This article considers and tests one such method for Big Language Data downsampling of digitally accessible language data to determine both how to operationalize this form of corpus model creation, as well as testing whether the method is reproducible. Using the U.S. Nuclear Regulatory Commission’s public documentation database as a test source, the sampling method’s procedure was evaluated to assess variation in the rate of which documents were deemed fit for inclusion or exclusion from the corpus across four iterations. After performing multiple sampling iterations, the approach pioneered by the Tobacco Documents Corpus creators was deemed to be reproducible and valid using a two-proportion z-test at a 99% confidence interval at each stage of the evaluation process–leading to a final mean rejection ratio of 23.5875 and variance of 0.891 for the documents sampled and evaluated for inclusion into the final text-based model. The findings of this study indicate that such a principled sampling method is viable, thus necessitating the need for an approach for creating language-based models that account for extralinguistic factors and linguistic characteristics of documents.
A K Nearest Neighborhood-Based Wind Estimation for Rotary-Wing VTOL UAVs
Authors: Wang Liyang , Misra Gaurav , Bai Xiaoli
Published: April 2019

Wind speed estimation for rotary-wing vertical take-off and landing (VTOL) UAVs is challenging due to the low accuracy of airspeed sensors, which can be severely affected by the rotor’s down-wash effect. Unlike traditional aerodynamic modeling solutions, in this paper, we present a K Nearest Neighborhood learning-based method which does not require the details of the aerodynamic information. The proposed method includes two stages: an off-line training stage and an on-line wind estimation stage. Only flight data is used for the on-line estimation stage, without direct airspeed measurements. We use Parrot AR.Drone as the testing quadrotor, and a commercial fan is used to generate wind disturbance. Experimental results demonstrate the accuracy and robustness of the developed wind estimation algorithms under hovering conditions.
Estimating Mangrove Forest Volume Using Terrestrial Laser Scanning and UAV-Derived Structure-from-Motion
Authors: Warfield Angus D. , Leon Javier X.
Published: April 2019

Mangroves provide a variety of ecosystem services, which can be related to their structural complexity and ability to store carbon in the above ground biomass (AGB). Quantifying AGB in mangroves has traditionally been conducted using destructive, time-consuming, and costly methods, however, Structure-from-Motion Multi-View Stereo (SfM-MVS) combined with unmanned aerial vehicle (UAV) imagery may provide an alternative. Here, we compared the ability of SfM-MVS with terrestrial laser scanning (TLS) to capture forest structure and volume in three mangrove sites of differing stand age and species composition. We describe forest structure in terms of point density, while forest volume is estimated as a proxy for AGB using the surface differencing method. In general, SfM-MVS poorly captured mangrove forest structure, but was efficient in capturing the canopy height for volume estimations. The differences in volume estimations between TLS and SfM-MVS were higher in the juvenile age site (42.95%) than the mixed (28.23%) or mature (12.72%) age sites, with a higher stem density affecting point capture in both methods. These results can be used to inform non-destructive, cost-effective, and timely assessments of forest structure or AGB in mangroves in the future.
Correction of Accounting Errors through Post Balance Sheet Event Analysis for Romanian Companies
Authors: Zlati Monica Laura , Antohi Valentin Marian , Cardon Petronela
Published: April 2019

The study scope is to present the typology of the events analyzed through our research and their impact on the quality of reported financial data. The objectives of the study are to analyze the vulnerability of enterprises according to methodological criteria such as risks and calculations of the risk profile, as well as to establish the necessary measures for correcting the accounting errors based on the conclusions drawn from the analysis. The method used is prospective, financial analysis of the data taken from the financial statements of the companies included in the sample, dynamic for a period of 6 years (2011–2016). Based on the method used, a risk model has been conceptualized to identify the vulnerabilities and risks reported in the financial statements and to define a company risk profile based on which error correction measures can be adopted. Considering the amplitude of the necessary check-ups and the methodology of the imposed accounting treatments, we believe that the topic addressed is a real area of interest for the professional accountants because it organizes the application procedures and limits the impact of errors on the quality of financial reporting in Romania.
Impact of Co-Channel Interference on Two-Way Relaying Networks with Maximal Ratio Transmission
Authors: Aladwani Awfa , Erdogan Eylem , Gucluoglu Tansal
Published: April 2019

Amplify-and-forward (AF) two-way relay networks (TWRNs) have become popular to provide spectrally efficient communication when range extension or energy efficiency is needed by utilizing a simple relay. However, their performance can be significantly degraded in practice due to co-channel interference (CCI) which is increasing due to growing number of wireless devices and recent cognitive and non-orthogonal multiple access techniques. With the motivation of improving the performance of AF-TWRNs, the use of maximal ratio transmission (MRT) is investigated to achieve high reliability while requiring low receiver complexity for the relay. First, the signal-to-interference-plus-noise ratio (SINR) expression is formulated and upper bounded. Then, tight lower bound expressions of outage probability (OP), sum symbol error rate (SSER), and upper bound ergodic sum rate (ESR) for each source and for the overall system are obtained. Besides, array and diversity gains are provided after deriving the asymptotic expressions of OP and SSER at high signal-to-noise ratio (SNR). Furthermore, the impact of channel estimation errors on the performance is also included. Finally, Monte Carlo simulation results which corroborate our theoretical findings are illustrated.
A Novel Arc Fault Detection Method Integrated Random Forest, Improved Multi-scale Permutation Entropy and Wavelet Packet Transform
Authors: Yin Zhendong , Wang Li , Zhang Yaojia , Gao Yang
Published: April 2019

Arc faults are one of the important causes of electric fires. In order to solve the problem of randomness, diversity, the concealment of series arc faults and to improve the detection accuracy, a novel arc fault detection method integrated random forest (RF), improved multi-scale permutation entropy (IMPE) and wavelet packet transform (WPT) are designed. Firstly, singular value decomposition (SVD) was applied to filter the current signal and then the high-dimensional fault features were constructed by extracting IMPE, the wavelet packet energy and the wavelet packet energy-entropy. Afterward, the high-dimensional fault features were employed to train the RF to realize the arc fault detection of different load types and the experimental results verify the effectiveness of the arc fault detection method designed in this paper. Finally, the comparative experiments demonstrates that the RF shows better performance in arc fault detection compared to the back-propagation neural network (BPNN) and least squares support vector machines (LSSVM), and that the experiments of transient events indicate that RF is able to effectively avoid incorrectly detecting different load types during the start operations and stop operations.
Stackelberg Game-Theoretic Low Probability of Intercept Performance Optimization for Multistatic Radar System
Authors: Shi Chenguang , Qiu Wei , Wang Fei , Salous Sana , Zhou Jianjiang
Published: April 2019

In this paper, the problem of Stackelberg game-theoretic low probability of intercept (LPI) performance optimization in multistatic radar system is investigated. The goal of the proposed LPI optimization strategy is to minimize the transmitted power of each radar while satisfying a predetermined signal-to-interference-plus-noise ratio (SINR) requirement for target detection. Firstly, a single-leader multi-follower Stackelberg game is adopted to formulate the LPI optimization problem of multistatic radar system. In the considered game model, the hostile intercept receiver plays a role of leader, who decides the prices of power resource first through the maximization of its own utility function. The multiple radars are followers to compete with each other in a non-cooperative game according to the imposed prices from the intercept receiver subsequently. Then, the Nash equilibrium (NE) for the considered game model is derived, and the existence and uniqueness of the NE are analytically proved. Furthermore, a pricing-based distributed iterative power control algorithm is proposed. Finally, some simulation examples are provided to demonstrate that the proposed scheme has remarkable potential to enhance the LPI performance of the multistatic radar system.
Real-Time Idle Time Cancellation by Means of Miniterm 4.0
Authors: Garcia Eduardo , Montés Nicolás
Published: April 2019

The paper presents how single-model robotized manufacturing lines are rebalanced to save energy. The key idea is to eliminate idle time that each robot has by means of adjusting the velocity. To do so, the proposed technique predicts the idle time for the next cycle time based on miniterm 4.0. This system measures in real-time the sub-cycle times (mini-terms) with the goal to detect disturbances that predict future machine failures. Mini-terms are used to compute the idle time and the allowed velocity reduction for the Industrial Robot without losing productivity. The proposed predictive control technique has been tested in a real production line located at Ford Almussafes plant (Valencia). The line has six stations where each one has an industrial robot. It is connected to miniterm 4.0 to perform a real test. A discussion, limitations of the technique, future implementations and conclusions are shown at the end of this paper.
Factors Affecting the Distribution of Pine Pitch Canker in Northern Spain
Authors: Blank Lior , Martín-García Jorge , Bezos Diana , Vettraino Anna Maria , Krasnov Helena , Lomba José M. , Fernández Mercedes , Diez Julio J.
Published: April 2019

Fusarium circinatum is the causal agent of pine pitch canker disease (PPC), affecting Pinus species and other conifers (i.e., Pseudotsuga menziesii (Mirb.) Franco.), forming resinous cankers on the main stem and branches and causing dieback in the terminal guide. This pathogen is spreading worldwide, causing economic losses by converting plantations into standing timber without any potential for future production. The disease was recently detected in Northern Spain in plantations of Pinus radiata and forest nurseries. The aim of the work reported here was to study the role of climatic and topographic variables, soil properties, and stand characteristics on PPC. For this purpose, we surveyed 50 pine stands in Cantabria and quantified the percentage of trees showing three symptoms in each stand: canker, defoliation, and dieback. We investigated the predictive power of 30 variables using generalized linear models and hierarchical partitioning. Both approaches yielded similar results. We found that the three symptoms correlated with different explanatory variables. In addition, more trees exhibited cankers in the proximity of the coast and the Basque Country. Additionally, our results showed that low canopy cover is related to a high level of the dieback symptom. Overall, this study highlights the important variables affecting the distribution of PPC in Cantabria.
Detailed Research on the Turbulent Kinetic Energy’s Distribution in Fishways in Reference to the Bolt Fishway
Authors: Puzdrowska Marta , Heese Tomasz
Published: April 2019

Turbulent kinetic energy (TKE) and its distribution and volume remain—with the exception of flow velocity—the most important cause of the low efficiency of fish passes. Thus, it is important to define the reasons and mechanisms that explain the distribution of characteristic features of this parameter, as presented in the paper. This publication presents the spatial distribution of TKE for two models of bolt-type fishways. The paper shows details related to characteristic features of TKE distribution and intensity scale in a bolt fishway. The presented research results for the bolt fishway were obtained from laboratory tests using a physical model. Measurements were taken of three temporary components of flow velocity in the indicated measurement sections. It was established that differences in the TKE volume and distribution are a consequence of the state of the stream that leaves the slot’s section or the orifice’s section. This state is defined by the determination of the stream’s potential. A low potential results in high TKE values in the area of the main flow. Thus, considering various structural features of fish passes, one can assert that the potential remains a characteristic feature attributable to a particular type of facility.
Facebook and WhatsApp as Elements in Transnational Care Chains for the Trinidadian Diaspora
Authors: Plaza Dwaine , Plaza Lauren
Published: April 2019

Despite being separated by great geographical distances, the Trinidadian Diaspora community has managed to stay in regular communication with those back “home” using the latest available technologies. Trinidadian migrants living abroad have established multi-directional care chains with family, kin, and friends that have endured for decades. This social connection has evolved from letter writing, telegrams, telephones, emails, and most recently, internet-based social media which includes: Facebook, WhatsApp, Skype, Facetime, Snapchat, Twitter, and Google Hangout. This paper examines how social media, focusing on Facebook and WhatsApp, are tools being used by the Trinidadian Diaspora to provide transnational care-giving to family and friends kin left behind in the “home” country and beyond. The analysis is based on the results of two online Qualtrics surveys, one implemented in 2012 (n = 150) and another in 2015 (n = 100) of Trinidadian Diaspora participants and in-depth interviews with (n = 10) Canadian-Trinidadians. This paper explores how social media have become a virtual transnational bridge that connects the Trinidadian Diaspora across long distances and provides family members with a feeling of psychological well-being.
Analysis of DNA Methylation Patterns Associated with In Vitro Propagated Globe Artichoke Plants Using an EpiRADseq-Based Approach
Authors: Cerruti Elisa , Comino Cinzia , Acquadro Alberto , Marconi Gianpiero , Repetto Anna Maria , Pisanu Anna Barbara , Pilia Roberto , Albertini Emidio , Portis Ezio
Published: April 2019

Globe artichoke represents one of the main horticultural species of the Mediterranean basin, and ‘Spinoso sardo’ is the most widespread and economically relevant varietal type in Sardinia, Italy. In the last decades, in vitro culture of meristematic apices has increased the frequency of aberrant plants in open-field production. These off-type phenotypes showed highly pinnate-parted leaves and late inflorescence budding, and emerged from some branches of the true-to-type ‘Spinoso sardo’ plants. This phenomenon cannot be foreseen and is reversible through generations, suggesting the occurrence of epigenetic alterations. Here, we report an exploratory study on DNA methylation patterns in off-type/true-to-type globe artichoke plants, using a modified EpiRADseq technology, which allowed the identification of 2897 differentially methylated loci (DML): 1998 in CG, 458 in CHH, and 441 in CHG methylation contexts of which 720, 88, and 152, respectively, were in coding regions. Most of them appeared involved in primary metabolic processes, mostly linked to photosynthesis, regulation of flower development, and regulation of reproductive processes, coherently with the observed phenotype. Differences in the methylation status of some candidate genes were integrated with transcriptional analysis to test whether these two regulation levels might interplay in the emergence and spread of the ‘Spinoso sardo’ non-conventional phenotype.
The Complex Interplay between Metabolic Reprogramming and Epigenetic Alterations in Renal Cell Carcinoma
Authors: Lameirinhas Ana , Miranda-Gonçalves Vera , Henrique Rui , Jerónimo Carmen
Published: April 2019

Renal cell carcinoma (RCC) is the most common malignancy affecting the kidney. Current therapies are mostly curative for localized disease, but do not completely preclude recurrence and metastization. Thus, it is imperative to develop new therapeutic strategies based on RCC biological properties. Presently, metabolic reprograming and epigenetic alterations are recognized cancer hallmarks and their interactions are still in its infancy concerning RCC. In this review, we explore RCC biology, highlighting genetic and epigenetic alterations that contribute to metabolic deregulation of tumor cells, including high glycolytic phenotype (Warburg effect). Moreover, we critically discuss available data concerning epigenetic enzymes’ regulation by aberrant metabolite accumulation and their consequences in RCC emergence and progression. Finally, we emphasize the clinical relevance of uncovering novel therapeutic targets based on epigenetic reprograming by metabolic features to improve treatment and survival of RCC patients.
Stakes and Challenges for Underwater Cultural Heritage in the Era of Blue Growth and the Role of Spatial Planning: Implications and Prospects in Greece
Authors: Papageorgiou Marilena
Published: April 2019

Underwater cultural heritage (UCH) constitutes an invaluable asset, which is lately being challenged by the blue growth trend that cannot be easily reconciled with the goal of UCH preservation and promotion. Maritime spatial planning (MSP)—under a place-based approach—creates better chances for UCH to receive more attention in the future compared to other resources, since it is considered to be the key procedure for tackling growing competition among sea users (user-user conflicts) and for mitigating the pressure these users put on the marine environment (natural and cultural). In Greece, a country with great insularity, extensive marine space, and a long and glorious past, UCH resources are in abundance. According to the official Ministry of Culture data-base, there are 88 designated UCH sites throughout the national waters, the majority of which are found very close to the shore. They usually concern ancient cities and built monuments that were eventually submerged (due to earthquakes, geological processes, etc.), so they usually have a mixed nature—terrestrial and marine. These sites, however, constitute a very small part of what is actually lying on the Greek seabed. Estimations for the future identify a rise in accidental discoveries of UCH, due to the blue growth trend and an increase in access to and work in the sea. In this event, much controversy is expected, concerning the appropriate type of management for UCH. The role of MSP in this decision-making process will be decisive, being about “when” and “where” human activities take place at sea, to ensure these are as efficient and sustainable as possible.
Accelerated Silicosis—An Emerging Epidemic Associated with Engineered Stone. Comment on Leso, V. et al. Artificial Stone Associated Silicosis: A Systematic Review. Int. J. Environ. Res. Public Health 2019, 16 (4), 568, doi:10.3390/ijerph16040568
Authors: Edwards Graeme
Published: April 2019

The systematic review by Leso et al. (16 February 2019) is a timely contribution to the body of knowledge concerning silicosis. It highlights the lack of quality data necessary to inform both occupational health risk management and the clinical management of workers exposed to respirable crystalline silica. This communication highlights current activity being undertaken in Queensland, Australia, that will further inform our knowledge concerning this entirely preventable disease. We are about half-way through a government-funded, case-finding program involving over 800 workers from the engineered stone bench-top fabrication industry. As of 15 February 2019, 99 confirmed cases of silicosis associated with engineered stone work were identified; nearly all were asymptomatic. The empirically observed false negative rate of ILO CXRs in this high-risk group appeared significantly greater than 10%. From pooled data, we hope to develop an appropriate index of exposure to trigger health surveillance using low-dose chest HRCT. Once a worker develops symptoms of silicosis, apart from lung transplantation, there are no treatment options currently available.
Kelvin-Helmholtz Billows Induced by Shear Instability along the North Passage of the Yangtze River Estuary, China
Authors: Shi Jian , Tong Chaofeng , Zheng Jinhai , Zhang Chi , Gao Xiangyu
Published: April 2019

Kelvin-Helmholtz (K-H) instability plays a significant role in mixing. To investigate the existence of K-H instability along the North Passage of the Yangtze River Estuary, the non-hydrostatic model NHWAVE is utilized to simulate the fresh-salt water mixing process along the North Passage of the Yangtze River Estuary. Using high horizontal resolution, the structure of K-H billows have been successfully captured within the Lower Reach of the North Passage. The K-H instability occurs between the max flood and high-water slack. The duration and length scale of the K-H billows highly depends on the local interaction between fresh-water discharge and tide. The horizontal length scale of the instability is about 60 m, similar to the observations in other estuaries. In the vertical direction, the K-H billows exist within the pycnocline with length scale ranging from 6 to 7 m. The timescale of the billows is approximate 6 min. By analyzing the changes of potential energy during the mixing process, results show that the existence of K-H instability induces intense vertical mixing, which can greatly increase mixing efficiency in the North Passage of the Yangtze River Estuary.
Wear Evolution of the Glass Fiber-Reinforced PTFE under Dry Sliding and Elevated Temperature
Authors: Huang Ruoxuan , Ma Siqi , Zhang Meidi , Yang Jie , Wang Dehong , Zhang Liang , Xu Jiujun
Published: April 2019

The wear evolution of the glass fiber reinforced Polytetrafluoroethylene (PTFE) sliding against duplex steel at elevated temperature was investigated using the interrupted wear tests coupling with the worn surface observations. The morphological changes of the PTFE composite during the sliding were related to the variation of the tribological properties to analyze the underlying wear mechanisms. Results show that the coefficient of friction and wear rate change with the increase of temperature. During the sliding, three regions can be identified regardless of the temperature. The high temperature is beneficial to the formation of tribo-film. The sequence of wear evolution is PTFE removal, load transfer to glass fiber, and minor formation of tribo-film for the low temperature condition. For high temperatures, the wear behaviors are more complicated. The different phenomena include the third body abrasion, flake delamination of PTFE matrix, scratching and reformation of transfer film on the counterface, and the filling of the large scale PTFE groove. These behaviors may dominate the different stages in the stable region, but occur simultaneously and cause the dynamic steady wear. As a result, the wear rate at 200 °C is slightly fluctuant.
Role of Polymeric Coating on Metallic Foams to Control the Aeroacoustic Noise Reduction of Airfoils with Permeable Trailing Edges
Authors: Hedayati Reza , Rubio Carpio Alejandro , Luesutthiviboon Salil , Ragni Daniele , Avallone Francesco , Casalino Damiano , van der Zwaag Sybrand
Published: April 2019

Studies on porous trailing edges, manufactured with open-cell Ni-Cr-Al foams with sub-millimeter pore sizes, have shown encouraging results for the mitigation of turbulent boundary-layer trailing-edge noise. However, the achieved noise mitigation is typically dependent upon the pore geometry, which is fixed after manufacturing. In this study, a step to control the aeroacoustics effect of such porous trailing edges is taken, by applying a polymeric coating onto the internal foam structure. Using this method, the internal topology of the foam is maintained, but its permeability is significantly affected. This study opens a new possibility of aeroacoustic control, since the polymeric coatings are temperature responsive, and their thickness can be controlled inside the foam. Porous metallic foams with pore sizes of 580, 800, and 1200 μm are (internally) spray-coated with an elastomeric coating. The uncoated and coated foams are characterized in terms of reduced porosity, average coating thickness and air-flow resistance. Subsequently, the coated and uncoated foams are employed to construct tapered inserts installed at the trailing edge of an NACA 0018 airfoil. The noise mitigation performances of the coated metal foams are compared to those of uncoated metal foams with either similar pore size or permeability value, and both are compared to the solid trailing edge reference case. Results show that that the permeability of the foam can be easily altered by the application of an internal coating on the metallic foams. The noise reduction characteristics of the coated foams are similar to equivalent ones with metallic materials, provided that the coating material is rigid enough not to plastically deform under flow conditions.
Improved DC Dielectric Performance of cPP-g-MAH/iPP/SEBS Composite with Chemical Graft Modification
Authors: Zhou Yu , Yang Jiaming , Zhao Hong , Sun Weifeng , Gao Mingze , Zhao Xindong , Hu Ming , Xie Shuhong
Published: April 2019

In order to achieve both high toughness and favorable dielectric properties of polypropylene materials, a styrene–butadiene–styrene block copolymer (SEBS) was employed as a toughening filler, in addition to a copolymerized polypropylene grafted by maleic anhydride (cPP-g-MAH) as a compatibilization modifier, to develop a novel isotactic polypropylene (iPP) composite (cPP-g-MAH/iPP/SEBS composite) with significantly improved direct-current (DC) dielectric performance and tenacity. The underlying physical and chemical mechanisms of modifying electric insulation were studied utilizing micro-structure characterization methods in combination with multiple thermal–mechanic–electric tests. The SEBS phase islands are uniformly distributed in the PP matrix with evidently improved dispersion due to cPP-g-MAH compatibilization. Compared with iPP, the elastic modulus of cPP-g-MAH/iPP/SEBS composites can be reduced by 58% with doubled thermal elongation, which is still superior to that of cross-linked polyethylene (XLPE), implying that the composites are qualified in terms of mechanical properties for use as power cables. The space charge accumulation and electric conduction are considerably suppressed in comparison with pure iPP and the iPP/SEBS composite. In the interest of charge-trapping characteristics modified by chemically grafting MAH, the deep traps introduced into polypropylene by grafting MAH were measured with a thermal stimulation current experiment to be 1.2 and 1.6 eV of energy level in trapping depth, verified through the first-principles electronic structure calculations with an all-electron numerical orbital scheme. It was concluded that the acquired high density of deep traps can effectively restrict the carrier transport and suppress the injection of space charge, resulting in a remarkable improvement of DC dielectric properties for the MAH grafted composites. The present work demonstrates that the cPP-g-MAH/iPP/SEBS composites are eligible to be applied to polypropylene-based high-voltage DC cables due to their excellent DC insulation performance, together with the appropriate mechanical properties.
Multiblock Mortar Mixed Approach for Second Order Parabolic Problems
Authors: Arshad Muhammad , Sana Madiha , Mustahsan Muhammad
Published: April 2019

In this paper, the multiblock mortar mixed approximation of second order parabolic partial differential equations is considered. In this method, the simulation domain is decomposed into the non-overlapping subdomains (blocks), and a physically-meaningful boundary condition is set on the mortar interface between the blocks. The governing equations hold locally on each subdomain region. The local problems on blocks are coupled by introducing a special approximation space on the interfaces of neighboring subdomains. Each block is locally covered by an independent grid and the standard mixed finite element method is applied to solve the local problem. The unique solvability of the discrete problem is shown, and optimal order convergence rates are established for the approximate velocity and pressure on the subdomain. Furthermore, an error estimate for the interface pressure in mortar space is presented. The numerical experiments are presented to validate the efficiency of the method.
Nonenzymatic Serum Antioxidant Capacity in IBD and Its Association with the Severity of Bowel Inflammation and Corticosteroids Treatment
Authors: Neubauer Katarzyna , Kempinski Radoslaw , Matusiewicz Malgorzata , Bednarz-Misa Iwona , Krzystek-Korpacka Malgorzata
Published: April 2019

Background and objectives: Oxidative stress signalling plays a monumental role in inflammatory bowel disease (IBD). Reduction of oxidative stress might control inflammation, block tissue damage, and reverse natural history of IBD. We assessed the serum concentrations of free thiols (FT) and uric acid (SUA), together constituting a large part of nonenzymatic serum antioxidant capacity, as well as total antioxidant status (TAS) with reference to IBD phenotype, activity, co-occurrence of anemia, and treatment with azathioprine (AZA) and corticosteroids (CS). Additionally, we appraised the potential of uric acid, thiol stress, and TAS as mucosal healing (MH) markers in ulcerative colitis. Materials and methods: SUA, FT, and TAS were measured colorimetrically using, respectively, uricase, Ellman’s and 2,2′-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS) methods. Results: The study group consisted of 175 individuals: 57 controls, 71 ulcerative colitis (UC), and 47 Crohn’s disease (CD) patients. When compared to controls, SUA levels were significantly lower in patients with CD, and FT and TAS levels were significantly lower in patients with CD and UC. In UC patients, SUA, FT, and TAS inversely correlated with the severity of bowel inflammation. As MH markers, SUA displayed better overall accuracy and higher specificity than FT. In active CD, FT, and SUA were significantly lower in patients with anemia. FT was significantly lower in patients treated with corticosteroids. Conclusions: IBD patients, regardless the disease phenotype, have systemic thiol stress, depleted total antioxidant capacity, and reduced concentrations of uric acid, reflecting, to various degrees, clinical and local disease activity as well as presence of anaemia, the most common extraintestinal manifestation of IBD. Evaluation of systemic total antioxidant status may be useful in noninvasive assessment of mucosal healing. Our findings on thiol stress provide an additional aspect on adverse effects of corticosteroids therapy.
Optimization, by Means of a Design of Experiments, of Heat Processes to Increase the Erosive Wear Resistance of White Hypoeutectic Cast Irons Alloyed with Cr and Mo
Authors: Gonzalez-Pociño Alejandro , Alvarez-Antolin Florentino , Asensio-Lozano Juan
Published: April 2019

To identify the design parameters in heat treatments that have a significant effect on the erosive wear resistance of hypoeutectic high chromium white cast irons, a design of experiment was applied to a white cast iron with 18wt.% Cr and 2wt.% Mo. The analyzed factors were the destabilization heat treatment of austenite (1000 or 1100 °C, for 4 or 8 h), different quench cooling media (in air or oil), different tempering treatments (200 or 500 °C, for 3 or 6 h), and the application of an ionic nitriding treatment. Despite what was expected, the nitriding treatment was not found to have a significant effect on said wear resistance. However, it is concluded that the highest wear resistance is obtained with the shortest dwell time at the destabilization temperature (4 h), quenching in oil, and with the shortest tempering times (3 h). Among the nitrided samples, the highest nitrided layer thicknesses were obtained when the destabilization temperature of the austenite was 1000 °C and the tempering temperature was 200 °C.
γ-Radiation Enhanced Luminescence of Thiol-Capped Quantum Dots in Aqueous Solution
Authors: Chang Shuquan , Wu Xian , Lan Jianzhang , Li Zheng , Zhang Xiaohong , Zhang Haiqian
Published: April 2019

Quantum dots (QDs) have attracted great attention due to their unique optical properties. High fluorescence efficiency is very important for their practical application. In this study, we report a simple and efficient strategy to enhance the photoluminescence of water-dispersed thiol-capped QDs using γ-radiation. Three kinds of QDs with different surface ligands and cores (MPA-CdTe, MPA-CdSe and Cys-CdTe) were fabricated and irradiated by high-energy γ-ray in an aqueous solution. Their photoluminescence intensities were significantly enhanced after irradiation, which were closely related to the radiation dose and the structure of QDs. The positions of the fluorescence emission peaks did not shift obviously after irradiation. The mechanism of photoluminescence enhancement was discussed based on the results of photoluminescence (PL) spectra, UV-visible light absorption (UV-vis) spectra, transmission electron microscope (TEM), X-ray diffraction (XRD) patterns, Fourier transform infrared (FT-IR) spectra and X-ray photoelectron spectroscopy (XPS). This method can be employed to uniformly treat large batches of QDs at room temperature and without other chemicals.