bluuebunny/crossref_metadata_2025 huggingface dataset:
Lyapunov Functions to Caputo Fractional Neural Networks with Time-Varying Delays
Authors: Agarwal Ravi , Hristova Snezhana , O’Regan Donal
Published: May 2018

One of the main properties of solutions of nonlinear Caputo fractional neural networks is stability and often the direct Lyapunov method is used to study stability properties (usually these Lyapunov functions do not depend on the time variable). In connection with the Lyapunov fractional method we present a brief overview of the most popular fractional order derivatives of Lyapunov functions among Caputo fractional delay differential equations. These derivatives are applied to various types of neural networks with variable coefficients and time-varying delays. We show that quadratic Lyapunov functions and their Caputo fractional derivatives are not applicable in some cases when one studies stability properties. Some sufficient conditions for stability of equilibrium of nonlinear Caputo fractional neural networks with time dependent transmission delays, time varying self-regulating parameters of all units and time varying functions of the connection between two neurons in the network are obtained. The cases of time varying Lipschitz coefficients as well as nonLipschitz activation functions are studied. We illustrate our theory on particular nonlinear Caputo fractional neural networks.
Final Value Problems for Parabolic Differential Equations and Their Well-Posedness
Authors: Christensen Ann-Eva , Johnsen Jon
Published: May 2018

This article concerns the basic understanding of parabolic final value problems, and a large class of such problems is proved to be well posed. The clarification is obtained via explicit Hilbert spaces that characterise the possible data, giving existence, uniqueness and stability of the corresponding solutions. The data space is given as the graph normed domain of an unbounded operator occurring naturally in the theory. It induces a new compatibility condition, which relies on the fact, shown here, that analytic semigroups always are invertible in the class of closed operators. The general set-up is evolution equations for Lax–Milgram operators in spaces of vector distributions. As a main example, the final value problem of the heat equation on a smooth open set is treated, and non-zero Dirichlet data are shown to require a non-trivial extension of the compatibility condition by addition of an improper Bochner integral.
Large Scale Product Recommendation of Supermarket Ware Based on Customer Behaviour Analysis
Authors: Kanavos Andreas , Iakovou Stavros Anastasios , Sioutas Spyros , Tampakas Vassilis
Published: May 2018

In this manuscript, we present a prediction model based on the behaviour of each customer using data mining techniques. The proposed model utilizes a supermarket database and an additional database from Amazon, both containing information about customers’ purchases. Subsequently, our model analyzes these data in order to classify customers as well as products, being trained and validated with real data. This model is targeted towards classifying customers according to their consuming behaviour and consequently proposes new products more likely to be purchased by them. The corresponding prediction model is intended to be utilized as a tool for marketers so as to provide an analytically targeted and specified consumer behavior. Our algorithmic framework and the subsequent implementation employ the cloud infrastructure and use the MapReduce Programming Environment, a model for processing large data-sets in a parallel manner with a distributed algorithm on computer clusters, as well as Apache Spark, which is a newer framework built on the same principles as Hadoop. Through a MapReduce model application on each step of the proposed method, text processing speed and scalability are enhanced in reference to other traditional methods. Our results show that the proposed method predicts with high accuracy the purchases of a supermarket.
Layered Indium Selenide under High Pressure: A Review
Authors: Segura Alfredo
Published: May 2018

This paper intends a short review of the research work done on the structural and electronic properties of layered Indium Selenide (InSe) and related III–VI semiconductors under high pressure conditions. The paper will mainly focus on the crucial role played by high pressure experimental and theoretical tools to investigate the electronic structure of InSe. This objective involves a previous revision of results on the pressure dependence of the InSe crystal structure and related topics such as the equation of state and the pressure-temperature crystal phase diagram. The main part of the paper will be devoted to reviewing the literature on the optical properties of InSe under high pressure, especially the absorption experiments that led to the identification of the main optical transitions, and their assignment to specific features of the electronic structure, with the help of modern first-principles band structure calculations. In connection with these achievements we will also review relevant results on the lattice dynamical, dielectric, and transport properties of InSe, as they provided very useful supplementary information on the electronic structure of the material.
Optical Absorption and Reflectivity of a Molecular Cluster of Lithium Niobate Adsorbed on a Graphene Layer
Authors: Salas Osiris , Garces Eric , Magana Luis Fernando
Published: May 2018

We used density functional theory to study the adsorption of a molecular cluster of lithium niobate (LiNbO3) on a graphene layer. The cluster size is about 1.2 nm, and it has 11 molecules. We optimized the cluster, and then we calculated its interaction with the optimized graphene layer. We found that the cluster is adsorbed on the graphene layer with an adsorption energy of −2.2213 eV (−0.068 eV/atom). Afterwards, we calculated the reflectivity, and the optical absorption coefficients of the system cluster-graphene and of a graphene layer alone, to make a comparison. We found large differences in the values of these properties of the new system, with respect to the corresponding ones of graphene. We performed our calculations using the general gradient approximation (GGA), and the GGA modified for van der Waals interactions in order to take into account the long-range correlations.
Machine Learning with Applications in Breast Cancer Diagnosis and Prognosis
Authors: Yue Wenbin , Wang Zidong , Chen Hongwei , Payne Annette , Liu Xiaohui
Published: May 2018

Breast cancer (BC) is one of the most common cancers among women worldwide, representing the majority of new cancer cases and cancer-related deaths according to global statistics, making it a significant public health problem in today’s society. The early diagnosis of BC can improve the prognosis and chance of survival significantly, as it can promote timely clinical treatment to patients. Further accurate classification of benign tumours can prevent patients undergoing unnecessary treatments. Thus, the correct diagnosis of BC and classification of patients into malignant or benign groups is the subject of much research. Because of its unique advantages in critical features detection from complex BC datasets, machine learning (ML) is widely recognised as the methodology of choice in BC pattern classification and forecast modelling. In this paper, we aim to review ML techniques and their applications in BC diagnosis and prognosis. Firstly, we provide an overview of ML techniques including artificial neural networks (ANNs), support vector machines (SVMs), decision trees (DTs), and k-nearest neighbors (k-NNs). Then, we investigate their applications in BC. Our primary data is drawn from the Wisconsin breast cancer database (WBCD) which is the benchmark database for comparing the results through different algorithms. Finally, a healthcare system model of our recent work is also shown.
Cancer Diagnosis Using a Liquid Biopsy: Challenges and Expectations
Authors: Castro-Giner Francesc , Gkountela Sofia , Donato Cinzia , Alborelli Ilaria , Quagliata Luca , Ng Charlotte K. Y. , Piscuoglio Salvatore , Aceto Nicola
Published: May 2018

The field of cancer diagnostics has recently been impacted by new and exciting developments in the area of liquid biopsy. A liquid biopsy is a minimally invasive alternative to surgical biopsies of solid tissues, typically achieved through the withdrawal of a blood sample or other body fluids, allowing the interrogation of tumor-derived material including circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA) fragments that are present at a given time point. In this short review, we discuss a few studies that summarize the state-of-the-art in the liquid biopsy field from a diagnostic perspective, and speculate on current challenges and expectations of implementing liquid biopsy testing for cancer diagnosis and monitoring in the clinical setting.
Multi-Scroll Chaotic Attractors in SC-CNN via Hyperbolic Tangent Function
Authors: Günay Enis , Altun Kenan
Published: May 2018

A State Controlled-Cellular Neural Network (SC-CNN) based chaotic model for generating multi-scroll attractors via hyperbolic tangent function series is proposed in this paper. After presenting the double scroll generation, the presented SC-CNN system is used in multi-scroll chaotic attractor generation by adding hyperbolic tangent function series. By using equilibrium analysis and their stability such as Lyapunov exponent analysis, bifurcation diagrams and Poincaré map, the dynamical behaviors of the proposed system are theoretically analyzed and numerically investigated.
Evolution of Thermoelectric Properties of Zn4Sb3 Prepared by Mechanical Alloying and Different Consolidation Routes
Authors: Lee Pee-Yew , Lin Pei-Ho
Published: May 2018

In this research, a method combining the mechanical alloying with the vacuum sintering or hot pressing was adopted to obtain the compact of β-Zn4Sb3. Pure zinc and antimony powders were used as the starting material for mechanical alloying. These powders were mixed in the stoichiometry ratio of 4 to 3, or more Zn-rich. Single phase Zn4Sb3 was produced using a nominally 0.6 at. % Zn rich powder. Thermoelectric Zn4Sb3 bulk specimens have been fabricated by vacuum sintering or hot pressing of mechanically alloyed powders at various temperatures from 373 to 673 K. For the bulk specimens sintering at high temperature, phase transformation of β-Zn4Sb3 to ZnSb and Sb was observed due to Zn vaporization. However, single-phase Zn4Sb3 bulk specimens with 97.87% of theoretical density were successfully produced by vacuum hot pressing at 473 K. Electric resistivity, Seebeck coefficient, and thermal conductivity were evaluated for the hot pressed specimens from room temperature to 673 K. The results indicate that the Zn4Sb3 shows an intrinsic p-type behavior. The increase of Zn4Sb3 phase ratio can increase Seebeck coefficient but decrease electric conductivity. The maximum power factor and figure of merit (ZT) value were 1.31 × 10−3 W/mK2 and 0.81 at 600 K, respectively. The ZT value was lower than that reported in the available data for materials prepared by conventional melt growth and hot pressed methods, but higher than the samples fabricated by vacuum melting and heat treatment techniques.
Flame-Front Rate of Spread Estimates for Moderate Scale Experimental Fires Are Strongly Influenced by Measurement Approach
Authors: Johnston Joshua M. , Wheatley Melanie J. , Wooster Martin J. , Paugam Ronan , Davies G. Matt , DeBoer Kaitlin A.
Published: May 2018

Understanding wildfire rate of spread (RoS) is often a key objective of many fire behavior modelling and measurement exercises. Using instrumented moderate scale laboratory burns we provide an assessment of eight different methods of flame front RoS determination, including visible imagery (VIS) analysis techniques, use of thermocouple arrays, and four thermal infrared (IR) image analysis approaches. We are able to (1) determine how measurement approach influences derived RoS, and (2) recommend the best method to reproduce the accepted standard (Thermocouple Grid Array measurement) RoS without ground sampling. We find that derived RoS is statistically significantly influenced by the measurement approach, and that failing to fully account for directionality of the RoS may result in significant error. We identify one of the thermal infrared imaging methods (described in Paugam et al. 2013), as the most appropriate for providing rate and direction of spread at these scales of measurement.
Columbite-Group Minerals from New York Pegmatites: Insights from Isotopic and Geochemical Analyses
Authors: Lupulescu Marian V. , Chiarenzelli Jeffrey R. , Pecha Mark E. , Singer Jared W. , Regan Sean P.
Published: May 2018

Columbite crystals from niobium-yttrium-fluorine (NYF) pegmatites lacking zircon or containing metamict cyrtolite were analyzed for major and minor elements (Electron Microprobe (EMP)), trace elements (Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS)), and U-Pb geochronology (Laser AblationMulti-Collector-Inductively Coupled Plasma-Mass Spectrometry (LA-MC-ICP-MS)). All four pegmatite localities sampled are hosted by the Proterozoic Fordham gneiss and/or Paleozoic Bedford gneiss (Columbite-(Fe); Kinkel and Baylis localities) and the Manhattan Schist of Lower Paleozoic age (Columbite-(Mn); Fort George and Harlem River Drive localities) and yield Neoacadian ages. The weighted average U-Pb ages are 372.2 ± 8.2 Ma (Baylis Quarry), 371.3 ± 7.3 and 383.4 ± 8.9 Ma (Kinkel Quarry); 383 ± 15 Ma (185th St. and Harlem River Drive); and 372 ± 10 Ma (Fort George). A partial metamict zircon (“cyrtolite”) from the Kinkel Quarry yielded a weighted average U-Pb age of 376.9 ± 4.3 Ma. The Neoacadian ages obtained agree with those determined by thermal ionization mass spectrometry (TIMS) for zircon from Lithium-Cesium-Tantalum (LCT) pegmatites from Connecticut and Maine. No pegmatites temporally associated with the Taconic orogeny were found. The size, lack of common Pb, uniform U concentrations across crystal cross-sections, sufficient but moderate uranium concentrations, lack of metamictization, and consistency in U-Pb isotopic ratios for columbite samples BCB-COL, NYSM #25232, and NYSM #525.8 suggests they show promise as potential standards for oxide mineral LA-MC-ICP-MS geochronological analyses, however, additional characterization using ID-TIMS would be necessary to develop as such.
Multicamera, Multimethod Measurements for Hydromorphologic Laboratory Experiments
Authors: Radice Alessio , Zanchi Barbara
Published: May 2018

The realization of hydromorphologic laboratory experiments on the propagation of aggrading or degrading sediment fronts requires simultaneous measurements of the sediment feeding rate, the profile of the free surface, and the flume bed elevation. In this study, five action cameras and different image-processing techniques were employed to measure all the needed quantities automatically and with adequate temporal resolution. The measurement of the sediment feeding rate was determined by particle image velocimetry as a surrogate, correlated quantity: the surface velocity of the sediment flow along a vibrating channel was used as an upstream feeder. The profile of the free surface was measured by shooting an array of piezometers connected to the flume. Each piezometer pipe contained a buoyant black sphere that could be recognized by using tools for particle identification, thus determining the elevation of the free surface above the piezometric probe. Finally, the bed profile along the flume was measured at any instant by edge detection, locating the transition from a water layer to a sediment layer in images taken from the side of the flume. The paper describes the instrumentation and the methods, finally presenting the results obtained from a prototypal experiment. Potentialities and limitations of the proposed methods are discussed, together with some prospects on future use in systematic experimental campaigns.
2DPR-Tree: Two-Dimensional Priority R-Tree Algorithm for Spatial Partitioning in SpatialHadoop
Authors: Elashry Ahmed , Shehab Abdulaziz , Riad Alaa M. , Aboul-Fotouh Ahmed
Published: May 2018

Among spatial information applications, SpatialHadoop is one of the most important systems for researchers. Broad analyses prove that SpatialHadoop outperforms the traditional Hadoop in managing distinctive spatial information operations. This paper presents a Two Dimensional Priority R-Tree (2DPR-Tree) as a new partitioning technique in SpatialHadoop. The 2DPR-Tree employs a top-down approach that effectively reduces the number of partitions accessed to answer the query, which in turn improves the query performance. The results were evaluated in different scenarios using synthetic and real datasets. This paper aims to study the quality of the generated index and the spatial query performance. Compared to other state-of-the-art methods, the proposed 2DPR-Tree improves the quality of the generated index and the query execution time.
A Low-Cost Collaborative Location Scheme with GNSS and RFID for the Internet of Things
Authors: Jing Changfeng , Wang Shouqing , Wang Mingshu , Du Mingyi , Zhou Lei , Sun Tiancheng , Wang Jian
Published: May 2018

The emergence and development of the Internet of Things (IoT) has attracted growing attention to low-cost location systems when facing the dramatically increased number of public infrastructure assets in smart cities. Various radio frequency identification (RFID)-based locating systems have been developed. However, most of them are impractical for infrastructure asset inspection and management on a large scale due to their high cost, inefficient deployment, and complex environments such as emergencies or high-rise buildings. In this paper, we proposed a novel locating system by combing the Global Navigation Satellite System (GNSS) with RFID, in which a target tag was located with one RFID reader and one GNSS receiver with sufficient accuracy for infrastructure asset management. To overcome the cost challenge, one mobile RFID reader-mounted GNSS receiver is used to simulate multiple location known reference tags. A vast number of reference tags are necessary for current RFID-based locating systems, which means higher cost. To achieve fine-grained location accuracy, we utilize a distance-based power law weight algorithm to estimate the exact coordinates. Our experiment demonstrates the effectiveness and advantages of the proposed scheme with sufficient accuracy, low cost and easy deployment on a large scale. The proposed scheme has potential applications for location-based services in smart cities.
Multilevel Cloud Detection for High-Resolution Remote Sensing Imagery Using Multiple Convolutional Neural Networks
Authors: Chen Yang , Fan Rongshuang , Bilal Muhammad , Yang Xiucheng , Wang Jingxue , Li Wei
Published: May 2018

In high-resolution image data, multilevel cloud detection is a key task for remote sensing data processing. Generally, it is difficult to obtain high accuracy for multilevel cloud detection when using satellite imagery which only contains visible and near-infrared spectral bands. So, multilevel cloud detection for high-resolution remote sensing imagery is challenging. In this paper, a new multilevel cloud detection technique is proposed based on the multiple convolutional neural networks for high-resolution remote sensing imagery. In order to avoid input the entire image into the network for cloud detection, the adaptive simple linear iterative clustering (A-SCLI) algorithm was applied to the segmentation of the satellite image to obtain good-quality superpixels. After that, a new multiple convolutional neural networks (MCNNs) architecture is designed to extract multiscale features from each superpixel, and the superpixels are marked as thin cloud, thick cloud, cloud shadow, and non-cloud. The results suggest that the proposed method can detect multilevel clouds and obtain a high accuracy for high-resolution remote sensing imagery.
Vector Spatial Big Data Storage and Optimized Query Based on the Multi-Level Hilbert Grid Index in HBase
Authors: Jiang Hua , Kang Junfeng , Du Zhenhong , Zhang Feng , Huang Xiangzhi , Liu Renyi , Zhang Xuanting
Published: May 2018

Faced with the rapid growth of vector data and the urgent requirement of low-latency query, it has become an important and timely challenge to effectively achieve the scalable storage and efficient access of vector big data. However, a systematic method is rarely seen for vector polygon data storage and query taking spatial locality into account in the storage schema, index construction and query optimization. In the paper, we focus on the storage and topological query of vector polygon geometry data in HBase, and the rowkey in the HBase table is the concatenation of the Hilbert value of the grid cell to which the center of the object entity’s MBR belongs, the layer identifier and the order code. Then, a new multi-level grid index structure, termed Q-HBML, that incorporates the grid-object spatial relationship and a new Hilbert hierarchical code into the multi-level grid, is proposed for improving the spatial query efficiency. Finally, based on the Q-HBML index, two query optimization strategies and an optimized topological query algorithm, ML-OTQ, are presented to optimize the topological query process and enhance the topological query efficiency. Through four groups of comparative experiments, it has been proven that our approach supports better performance.
A New Alien Invasive Longhorn Beetle, Xylotrechus chinensis (Cerambycidae), Is Infesting Mulberries in Catalonia (Spain)
Authors: Sarto i Monteys Víctor , Torras i Tutusaus Glòria
Published: May 2018

In this paper, the invasion of a new alien beetle species to Europe, the longhorn Xylotrechus chinensis (Chevrolat) (Cerambycidae), originating from East Asia, is revealed. It has settled in Catalonia (Spain), occupying at present an area of at least 44.1 km2, where it has been shown to severely infest (ca. 10 to 45%) and eventually kill mulberry trees in private and public grounds. The main objective of this study was to evaluate its impact and provide new significant insights into its life history, seasonality, reproductive capacity (females produce an average of 83.4 ± 9.02 eggs) and the type of damage produced to mulberries. Such damage was thoroughly described to facilitate inspection by others. At least in laboratory conditions, X. chinensis has not used common grape vines as an alternative hostplant. Both plants, mulberries and grape vines, are important in Catalonia and Spain, the former providing shade and ornament to many streets and avenues, and the latter having great economic significance in Mediterranean wine production areas. Possible control methods to hinder its spread are suggested and one local wasp, Stephanus serrator (Stephanidae), was identified as a likely parasitoid. We believe the risk of this beetle widely spreading in Europe is very real.
Current Role of Lipoprotein Apheresis in the Treatment of High-Risk Patients
Authors: Julius Ulrich
Published: May 2018

Lipoprotein apheresis (LA) is a therapeutic approach to save the lives of patients who are at an extremely high risk of developing cardiovascular events (CVE), especially after all other therapeutic options were not tolerated, or appeared not to be effective enough. Homozygous familial hypercholesterolemia represents a clear indication to start LA therapy. Another recognized indication is a severe hypercholesterolemia, which induced CVE, often in association with other risk factors. In the last years, an expressive elevation of lipoprotein(a) (Lp(a)) emerged as an indication for LA. In Germany, progress of atherosclerosis should have been documented before the permission to start LA therapy is given in these patients. Usually, all LA methods acutely decrease both LDL-C and Lp(a). However, specific columns which reduce only Lp(a) are available. Case reports and prospective observations comparing the situation before and during LA therapy clearly show a high efficiency with respect to the reduction of CVE, especially in patients with high Lp(a) levels. PCSK9 inhibitors may reduce the need for LA in patients with heterozygous or polygenetic hypercholesterolemia, but in some patients, a combination of these drugs with LA will be necessary. In the future, an antisense oligonucleotide against apolipoprotein(a) may offer an alternative therapeutic approach.
Non-Local Sparse Image Inpainting for Document Bleed-Through Removal
Authors: Hanif Muhammad , Tonazzini Anna , Savino Pasquale , Salerno Emanuele
Published: May 2018

Bleed-through is a frequent, pervasive degradation in ancient manuscripts, which is caused by ink seeped from the opposite side of the sheet. Bleed-through, appearing as an extra interfering text, hinders document readability and makes it difficult to decipher the information contents. Digital image restoration techniques have been successfully employed to remove or significantly reduce this distortion. This paper proposes a two-step restoration method for documents affected by bleed-through, exploiting information from the recto and verso images. First, the bleed-through pixels are identified, based on a non-stationary, linear model of the two texts overlapped in the recto-verso pair. In the second step, a dictionary learning-based sparse image inpainting technique, with non-local patch grouping, is used to reconstruct the bleed-through-contaminated image information. An overcomplete sparse dictionary is learned from the bleed-through-free image patches, which is then used to estimate a befitting fill-in for the identified bleed-through pixels. The non-local patch similarity is employed in the sparse reconstruction of each patch, to enforce the local similarity. Thanks to the intrinsic image sparsity and non-local patch similarity, the natural texture of the background is well reproduced in the bleed-through areas, and even a possible overestimation of the bleed through pixels is effectively corrected, so that the original appearance of the document is preserved. We evaluate the performance of the proposed method on the images of a popular database of ancient documents, and the results validate the performance of the proposed method compared to the state of the art.
A Minimum Cross-Entropy Approach to Disaggregate Agricultural Data at the Field Level
Authors: Xavier António , Fragoso Rui , De Belém Costa Freitas Maria , Do Socorro Rosário Maria , Valente Florentino
Published: May 2018

Agricultural policies have impacts on land use, the economy, and the environment and their analysis requires disaggregated data at the local level with geographical references. Thus, this study proposes a model for disaggregating agricultural data, which develops a supervised classification of satellite images by using a survey and empirical knowledge. To ensure the consistency with multiple sources of information, a minimum cross-entropy process was used. The proposed model was applied using two supervised classification algorithms and a more informative set of biophysical information. The results were validated and analyzed by considering various sources of information, showing that an entropy approach combined with supervised classifications may provide a reliable data disaggregation.
N-(1-Deoxy-α-d-tagatopyranos-1-yl)-N-methylaniline (“d-Tagatose-N-methylaniline”)
Authors: Mossine Valeri , Barnes Charles , Mawhinney Thomas
Published: May 2018

Tagatosamines form in thermally-processed dairy products and contribute to the foods’ organoleptic and nutritional value. d-Tagatose-N-methylaniline (N-(1-deoxy-d-tagatos-1-yl)-N-methylaniline, 1-deoxy-1-(N-methylphenylamino)-d-tagatose) was synthesized from d-galactose via the Amadori rearrangement. In aqueous solution, it established an anomeric equilibrium consisting of 62.8% α-pyranose, 21.3% β-pyranose, 1.5% α-furanose, 8.1% β-furanose, and 6.2% acyclic keto tautomer. The crystalline α-pyranose anomer of d-tagatose-N-methylaniline adopted the 5C2 chair conformation. All hydroxyl and ring oxygen atoms and the amino nitrogen are involved in an extensive H-bonding network dominated by infinite homodromic chains. The Hirshfeld surface analysis suggests a significant contribution of non-polar intermolecular contacts to the crystal structure.
Chain Compounds Based on Paddle-wheel Copper(II) Carboxylate Bearing Four Nitroxide Radicals
Authors: Mikuriya Masahiro , Indrawati Renny , Hashido Rieko , Matsubara Shizuka , Nakamura Chizu , Yoshioka Daisuke , Yokota Kazuyuki , Fukuzaki Masafumi , Handa Makoto
Published: May 2018

Chain compounds of paddle-wheel Cu2-clusters of 3-carboxy-2,2,5,5-tetramethyl-1-pyrrolidinyloxy (Hcaproxy) and 4-carboxy-2,2,6,6-tetramethylpiperidinyloxy (Hcatempo) and N,N’-bidentate ligands (L = 4,4′-bipyridine (4,4′-bpy), 1,2-bis(4-pyridyl)ethane (bpe), trans-1,2-bis(4-pyridyl)ethylene (bpel), 4,4′-dipyridyl disulfide (pds), 1,4-diazabicyclo[2.2.2]octane (dabco), and pyrazine (pyz)), [Cu2(caproxy)4(L)]n, and [Cu2(catempo)4(L)]n, were synthesized and characterized by elemental analysis, infrared and UV-vis spectra and temperature dependence of magnetic susceptibilities (4.5–300 K). The crystal structures of [Cu2(caproxy)4(pds)]n, [Cu2(catempo)4(4,4′-bpy)]n, and [Cu2(catempo)4(bpe)]n revealed zigzag or linear chains consisting of alternate arrangement of the dinuclear cluster bearing four nitroxide radicals and N,N’-bidentate ligand. Temperature dependence of magnetic susceptibilities showed a considerable antiferromagnetic interaction between the two copper(II) ions within the dinuclear cluster, and weak antiferromagnetic interaction between the dinuclear clusters and/or the radical and dinuclear cluster.
On the Semigroup Whose Elements Are Subgraphs of a Complete Graph
Authors: Chaiya Yanisa , Pookpienlert Chollawat , Nupo Nuttawoot , Panma Sayan
Published: May 2018

Let K n be a complete graph on n vertices. Denote by S K n the set of all subgraphs of K n . For each G , H ∈ S K n , the ring sum of G and H is a graph whose vertex set is V ( G ) ∪ V ( H ) and whose edges are that of either G or H, but not of both. Then S K n is a semigroup under the ring sum. In this paper, we study Green’s relations on S K n and characterize ideals, minimal ideals, maximal ideals, and principal ideals of S K n . Moreover, maximal subsemigroups and a class of maximal congruences are investigated. Furthermore, we prescribe the natural order on S K n and consider minimal elements, maximal elements and covering elements of S K n under this order.
Methods to Evaluate Corrosion in Buried Steel Structures: A Review
Authors: Arriba-Rodriguez Lorena-de , Villanueva-Balsera Joaquin , Ortega-Fernandez Francisco , Rodriguez-Perez Fernando
Published: May 2018

Around the world, there are thousands of metal structures completely or partially buried in the soil. The main concern in their design is corrosion. Corrosion is a mechanism that degrades materials and causes structural failures in infrastructures, which can lead to severe effects on the environment and have direct impact on the population health. In addition, corrosion is extremely complex in the underground environment due to the variability of the local conditions. The problem is that there are many methods to its evaluation but none have been clearly established. In order to ensure the useful life of such structures, engineers usually consider an excess thickness that increases the economic cost of manufacturing and does not satisfy the principles of efficiency in the use of resources. In this paper, an extended revision of the existing methods to evaluate corrosion is carried out to optimize the design of buried steel structures according to their service life. Thus, they are classified into two categories depending on the information they provide: qualitative and quantitative methods. As a result, it is concluded that the most exhaustive methodologies for estimating soil corrosion are quantitative methods fed by non-electrochemical data based on experimental studies that measure the mass loss of structures.
Thermodynamic Considerations for a Pyrometallurgical Extraction of Indium and Silver from a Jarosite Residue
Authors: Steinlechner Stefan , Antrekowitsch Jürgen
Published: May 2018

Indium and silver are technologically important, critical metals, and in the majority of cases, they are extracted as a by-product of another carrier metal. The importance of indium has seen recent growth, and for technological reasons, these metals can be found in industrial residues from primary zinc production, such as the iron precipitate—jarosite. To secure the supply of such metals in Europe, and with the idea of a circular economy and the sustainable use of raw materials, the recycling of such industrial residues is coming into focus. Due to the low value of jarosite, the focus must lie simultaneously on the recovery of valuable metals and the production of high-quality products in order to pursue an economical process. The objective of this article is to give the fundamentals for the development of a successful process to extract the minor elements from roasted jarosite. As such, we use thermodynamic calculations to show the behavior of indium and silver, leading to a recommendation for the required conditions for a successful extraction process. In summary, the formation of chlorine compounds shows high potential to meet the challenge of simultaneously recovering these metals together with zinc at the lowest possible energy input.
Theoretical and Experimental Research on Bubble Actuated Micro-Pumps
Authors: Qu Yang , Zhou Junjie , Wu Wei
Published: May 2018

Bubble actuated micro-pumps have great potential to be integrated into microfluidic systems to allow the independence of peripheral equipment. Previous studies on bubble actuated valveless micro-pumps have been mainly limited to experimental studies and numerical simulations due to the complex behavior of bubbles. In this paper, the construction of a mathematical model for a bubble actuated valveless micro-pump considering fluid dynamics, heat and mass transfer and bubble dynamics is described. A prototype was fabricated and tested to verify this theoretical model. The morphological evolution of the driving bubbles during the heating process was observed by a high-speed charge-coupled device (CCD) camera, the flow rate produced by the micro-pump under different working conditions was recorded and the test results were explained by the heat dissipation model. The model in this study was able to precisely predict the flow of micro-pumps in different drive modes. The principle behind defining the heating frequency and the duty cycle based on the pump chamber volume was determined. The study shows the mechanism of bubble controlling and the good prospects of bubble actuated valveless micro-pumps.
Effect of Selective Encapsulation of Hydroxypropyl-β-cyclodextrin on Components and Antibacterial Properties of Star Anise Essential Oil
Authors: Zhang Guangjie , Yuan Chao , Sun Yonghai
Published: May 2018

Star anise essential oil (SAEO) is a plant essential oil with good antibacterial activity, but its applications are limited due to its high volatility, strong smell, and unstable physical and chemical properties. The effect of selective encapsulation of SAEO by hydroxypropyl-β-cyclodextrin (HPCD) on its compositions, volatility stability and antibacterial activity was investigated. The GC-MS results indicated that the compositions reduced and content of the compositions of SAEO changed after encapsulation. Most of the components in SAEO were successfully encapsulated by HPCD, which can be supported by data from FTIR and 1H NMR. According to the molecular modeling results, the three guest molecules (trans-anethole, estragole and trans-foeniculin) were all docked in the cavity of HPCD on the isoallyl (or allyl) side. The volatile stability of SAEO before and after encapsulation was evaluated by electronic nose, and the results confirmed that encapsulation significantly reduced the irritating smell of SAEO and makes the clathrate have a sustained release effect. Furthermore, in the antibacterial test, the selective encapsulation of HPCD improved the inhibition effect of SAEO on Rhizopus stolonoifer, Saccharomyces cerevisiae, and E. coli and its antibacterial stability in 24 h.
Short-Range Correlated Magnetic Core-Shell CrO2/Cr2O3 Nanorods: Experimental Observations and Theoretical Considerations
Authors: Gandhi Ashish , Li Tai-Yue , Chan Ting , Wu Sheng
Published: May 2018

With the evolution of synthesis and the critical characterization of core-shell nanostructures, short-range magnetic correlation is of prime interest in employing their properties to develop novel devices and widespread applications. In this regard, a novel approach of the magnetic core-shell saturated magnetization (CSSM) cylinder model solely based on the contribution of saturated magnetization in one-dimensional CrO2/Cr2O3 core-shell nanorods (NRs) has been developed and applied for the determination of core-diameter and shell-thickness. The nanosized effect leads to a short-range magnetic correlation of ferromagnetic core-CrO2 extracted from CSSM, which can be explained using finite size scaling method. The outcome of this study is important in terms of utilizing magnetic properties for the critical characterization of core-shell nanomagnetic materials.
Iron Oxide Colloidal Nanoclusters as Theranostic Vehicles and Their Interactions at the Cellular Level
Authors: Kostopoulou Athanasia , Brintakis Konstantinos , Fragogeorgi Eirini , Anthousi Amalia , Manna Liberato , Begin-Colin Sylvie , Billotey Claire , Ranella Anthi , Loudos George , Athanassakis Irene , Lappas Alexandros
Published: May 2018

Advances in surfactant-assisted chemical approaches have led the way for the exploitation of nanoscale inorganic particles in medical diagnosis and treatment. In this field, magnetically-driven multimodal nanotools that perform both detection and therapy, well-designed in size, shape and composition, are highly advantageous. Such a theranostic material—which entails the controlled assembly of smaller (maghemite) nanocrystals in a secondary motif that is highly dispersible in aqueous media—is discussed here. These surface functionalized, pomegranate-like ferrimagnetic nanoclusters (40–85 nm) are made of nanocrystal subunits that show a remarkable magnetic resonance imaging contrast efficiency, which is better than that of the superparamagnetic contrast agent Endorem©. Going beyond this attribute and with their demonstrated low cytotoxicity in hand, we examine the critical interaction of such nanoprobes with cells at different physiological environments. The time-dependent in vivo scintigraphic imaging of mice experimental models, combined with a biodistribution study, revealed the accumulation of nanoclusters in the spleen and liver. Moreover, the in vitro proliferation of spleen cells and cytokine production witnessed a size-selective regulation of immune system cells, inferring that smaller clusters induce mainly inflammatory activities, while larger ones induce anti-inflammatory actions. The preliminary findings corroborate that the modular chemistry of magnetic iron oxide nanoclusters stimulates unexplored pathways that could be driven to alter their function in favor of healthcare.
High-Switching-Ratio Photodetectors Based on Perovskite CH3NH3PbI3 Nanowires
Authors: Zhang Xin , Liu Caichi , Ren Gang , Li Shiyun , Bi Chenghao , Hao Qiuyan , Liu Hui
Published: May 2018

Hybrid organic-inorganic perovskite materials have attracted extensive attention due to their impressive performance in photovoltaic devices. One-dimensional perovskite CH3NH3PbI3 nanomaterials, possessing unique structural features such as large surface-to-volume ratio, anisotropic geometry and quantum confinement, may have excellent optoelectronic properties, which could be utilized to fabricate high-performance photodetectors. However, in comparison to CH3NH3PbI3 thin films, reports on the fabrication of CH3NH3PbI3 nanowires for optoelectrical application are rather limited. Herein, a two-step spin-coating process has been utilized to fabricate pure-phase and single-crystalline CH3NH3PbI3 nanowires on a substrate without mesoporous TiO2 or Al2O3. The size and density of CH3NH3PbI3 nanowires can be easily controlled by changing the PbI2 precursor concentration. The as-prepared CH3NH3PbI3 nanowires are utilized to fabricate photodetectors, which exhibit a fairly high switching ratio of ~600, a responsivity of 55 mA/W, and a normalized detectivity of 0.5 × 1011 jones under 532 nm light illumination (40 mW/cm2) at a very low bias voltage of 0.1 V. The as-prepared perovskite CH3NH3PbI3 nanowires with excellent optoelectronic properties are regarded to be a potential candidate for high-performance photodetector application.
Zinc, Magnesium, Selenium and Depression: A Review of the Evidence, Potential Mechanisms and Implications
Authors: Wang Jessica , Um Phoebe , Dickerman Barbra A. , Liu Jianghong
Published: May 2018

Micronutrient deficiency and depression are major global health problems. Here, we first review recent empirical evidence of the association between several micronutrients—zinc, magnesium, selenium—and depression. We then present potential mechanisms of action and discuss the clinical implications for each micronutrient. Collectively, empirical evidence most strongly supports a positive association between zinc deficiency and the risk of depression and an inverse association between zinc supplementation and depressive symptoms. Less evidence is available regarding the relationship between magnesium and selenium deficiency and depression, and studies have been inconclusive. Potential mechanisms of action involve the HPA axis, glutamate homeostasis and inflammatory pathways. Findings support the importance of adequate consumption of micronutrients in the promotion of mental health, and the most common dietary sources for zinc and other micronutrients are provided. Future research is needed to prospectively investigate the association between micronutrient levels and depression as well as the safety and efficacy of micronutrient supplementation as an adjunct treatment for depression.
Chemopreventive Activities of Sulforaphane and Its Metabolites in Human Hepatoma HepG2 Cells
Authors: Liu Peng , Wang Wei , Zhou Zhigang , Smith Andrew J. O. , Bowater Richard P. , Wormstone Ian Michael , Chen Yuqiong , Bao Yongping
Published: May 2018

Sulforaphane (SFN) exhibits chemopreventive effects through various mechanisms. However, few studies have focused on the bioactivities of its metabolites. Here, three metabolites derived from SFN were studied, known as sulforaphane glutathione, sulforaphane cysteine and sulforaphane-N-acetylcysteine. Their effects on cell viability, DNA damage, tumorigenicity, cell migration and adhesion were measured in human hepatoma HepG2 cells, and their anti-angiogenetic effects were determined in a 3D co-culture model of human umbilical vein endothelial cells (HUVECs) and pericytes. Results indicated that these metabolites at high doses decreased cancer cell viability, induced DNA damage and inhibited motility, and impaired endothelial cell migration and tube formation. Additionally, pre-treatment with low doses of SFN metabolites protected against H2O2 challenge. The activation of the nuclear factor E2-related factor 2 (Nrf2)-antioxidant response element (ARE) pathway and the induction of intracellular glutathione (GSH) played an important role in the cytoprotective effects of SFN metabolites. In conclusion, SFN metabolites exhibited similar cytotoxic and cytoprotective effects to SFN, which proves the necessity to study the mechanisms of action of not only SFN but also of its metabolites. Based on the different tissue distribution profiles of these metabolites, the most relevant chemical forms can be selected for targeted chemoprevention.
Intestinal Absorption and Antioxidant Activity of Grape Pomace Polyphenols
Authors: Chedea Veronica Sanda , Palade Laurentiu Mihai , Marin Daniela Eliza , Pelmus Rodica Stefania , Habeanu Mihaela , Rotar Mircea Catalin , Gras Mihail Alexandru , Pistol Gina Cecilia , Taranu Ionelia
Published: May 2018

The absorption and antioxidant activity of polyphenols from grape pomace (GP) are important aspects of its valorization as a feed additive in the diet of weaned piglets. This study aimed to evaluate the presence of polyphenols from GP both in vitro in IPEC cells and in vivo in the duodenum and colon of piglets fed with diets containing or not 5% GP and also to compare and correlate the aspects of their in vitro and in vivo absorption. Total polyphenolic content (TPC) and antioxidant status (TAS, CAT, SOD and GPx enzyme activity, and lipid peroxidation-TBARS level) were assessed in duodenum and colon of piglets fed or not a diet with 5% GP. The results of UV-Vis spectroscopy demonstrated that in cellular and extracellular medium the GP polyphenols were oxidized (between λmax = 276 nm and λmax = 627.0 nm) with the formation of o-quinones and dimers. LC-MS analysis indicated a procyanidin trimer possibly C2, and a procyanidin dimer as the major polyphenols identified in GP, 12.8% of the procyanidin trimer and 23% of the procyanidin dimer respectively being also found in the compound feed. Procyanidin trimer C2 is the compound accumulated in duodenum, 73% of it being found in the colon of control piglets, and 62.5% in the colon of GP piglets. Correlations exist between the in vitro and in vivo investigations regarding the qualitative evaluation of GP polyphenols in the cells (λmax at 287.1 nm) and in the gut (λmax at 287.5 nm), as oxidated metabolic products. Beside the presence of polyphenols metabolites this study shows also the presence of the unmetabolized procyanidin trimers in duodenum and colon tissue, an important point in evaluating the benefic actions of these molecules at intestinal level. Moreover the in vivo study shows that a 5% GP in piglet’s diet increased the total antioxidant status (TAS) and decreased lipid peroxidantion (TBARS) in both duodenum and colon, and increased SOD activity in duodenum and CAT and GPx activity in colon. These parameters are modulated by the different polyphenols absorbed, mainly by the procyanidin trimers and catechin on one side and the polyphenols metabolites on the other side.
Some Theoretical Aspects of Magnetars
Authors: Sinha Monika
Published: May 2018

Magnetars have been observationally determined to have surface magnetic fields of order of 10 14 – 10 15 G, and the implied internal field strength may be even larger. We discuss the effect of strong field on the dense matter expected to be inside neutron stars. We describe the microphysics, phenomenology, and astrophysical implications of strong field induced unpairing effect that may occur in magnetars, if the local magnetic field in the core of a magnetar exceeds a critical value. The density dependence of the pairing of proton condensate implies that the critical value required for the unpairing effect to occur is maximal at the crust–core interface and decreases towards the center of the star. As a consequence, magnetar cores with homogeneous constant fields will be partially superconducting for “medium-field” magnetars, whereas “strong-field” magnetars will be void of superconductivity. We also discuss its effect on some observational phenomena which depend on the nature and composition of matter inside neutron stars.
Sustained Release Drug Delivery Applications of Polyurethanes
Authors: Lowinger Michael B. , Barrett Stephanie E. , Zhang Feng , Williams Robert O.
Published: May 2018

Since their introduction over 50 years ago, polyurethanes have been applied to nearly every industry. This review describes applications of polyurethanes to the development of modified release drug delivery. Although drug delivery research leveraging polyurethanes has been ongoing for decades, there has been renewed and substantial interest in the field in recent years. The chemistry of polyurethanes and the mechanisms of drug release from sustained release dosage forms are briefly reviewed. Studies to assess the impact of intrinsic drug properties on release from polyurethane-based formulations are considered. The impact of hydrophilic water swelling polyurethanes on drug diffusivity and release rate is discussed. The role of pore formers in modulating drug release rate is examined. Finally, the value of assessing mechanical properties of the dosage form and approaches taken in the literature are described.