bluuebunny/crossref_metadata_2025_split huggingface dataset:
A domain decomposition semianalytical finite element scheme for electromagnetic simulations in layered media and waveguide discontinuities
Authors: Chen Jiefu 
Published: November 2016

ABSTRACTA novel domain decomposition semianalytical finite element method is proposed for modeling of electromagnetic wave propagation in layered media. A layered structure is decomposed into several domains. Conventional finite elements are used to discretize subdomains with inhomogeneous material or structural distributions. A recently developed high precision semianalytical finite element scheme is applied to layers with homogeneity along a specific direction. Domain decomposition based on Robin transmission conditions is used to hybridize subdomains with different discretization schemes, allowing nonconforming meshes on interfaces between subdomains. Numerical examples demonstrate that the proposed method is flexible and efficient in electromagnetic modeling of layered media and waveguide discontinuities. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:101–105, 2017
Integrated lens antenna array with full azimuth plane beam scanning capability at 60 GHz
Authors: Saleem Muhammad Kamran , Alkanhal Majeed A. S. , Sheta Abdel Fattah , Abdel‐Rahman M. , Himdi Mohammed 
Published: November 2016

ABSTRACTAn antenna array operating at 60 GHz is proposed. The proposed array covers impedance bandwidth of 5 GHz (57.5–62.5 GHz) with maximum gain of 16.25 dBi at 61. 5 GHz. With the proposed array 15 distinct radiation patterns in azimuth plane can be achieved, each having 3‐dB beamwidth of 24° and 3‐dB cross over. The beam scanning capability can be achieved by activating each array element one by one. Each array element consists of a conventional microstrip patch antenna (MPA) integrated with extended hemispherical Teflon lens. The Teflon lens is utilized to enhance the gain of conventional MPA as well as to achieve the desired elementary radiation pattern of array to cover full azimuth plane. A very good agreement between the measured and simulated results is observed. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:116–120, 2017
A low insertion loss, wideband and compact Wilkinson power divider/combiner with lumped components in 65 nm CMOS
Authors: Oh Hyun‐Myung , Lee Eun‐Gyu , Lim Jeong‐Taek , Lee Jae‐Eun , Woo Byeon Chul , Son JuHo , Ho Lee Jeong , Kim Choul‐Young 
Published: November 2016

ABSTRACTIn this article, a new design of a Wilkinson power divider is presented that offers substantially improved amplitude and reduced size characteristics over a broad frequency range compared to a conventional Wilkinson power divider. The improvement in bandwidth is obtained by reducing inductance and number of lumped components in even mode. The analytical design equations for this proposed power divider are obtained using even and odd mode analysis. This power divider with a compact size is fabricated using 65 nm 1P9M CMOS technology. The measurement results show an operation bandwidth 26–40 GHz with 15 dB input, output return loss, and 0.7 dB insertion loss. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:128–131, 2017
Nonlinear modeling method for DC trans‐conductance determination of GaAs MHEMTs
Authors: Nguyen Tung The‐Lam , Kim Sam‐Dong 
Published: November 2016

ABSTRACTWe propose in this study an empirical nonlinear model to extract DC intrinsic transconductance (gmDC) and output conductance (gdsDC) from the high frequency intrinsic parameter set. The proposed method based on a nonlinear equation show a very good agreement in DC I–V characteristics between the calculations and measurements with a fitting error of 0.25% and enables us successfully extract the gmDC and gdsDC. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:131–134, 2017
Log periodic slot‐loaded circular vivaldi antenna for 5–40 GHz UWB applications
Authors: Mazhar Waqas , Klymyshyn David , Qureshi Aqeel 
Published: November 2016

ABSTRACTA compact antipodal log periodic slot‐loaded circular Vivaldi antenna with dimension (L × W) 45 × 60mm is presented. Structural modification to the conventional antipodal Vivaldi antenna results in miniaturization, improved impedance and pattern bandwidth performance. Proposed designs are prototyped and measured to validate wide‐impedance bandwidths from 5 to 40 GHz. These are compared to measurements on similarly fabricated traditional antipodal and circular Vivaldi antennas which shows a bandwidth only up to 26 GHz. In addition, the measured antenna gain and radiation efficiency of the log periodic slot‐loaded circular Vivaldi antenna are also found higher than the conventional designs. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:159–163, 2017
A differential‐fed Yagi–Uda antenna with enhanced bandwidth via addition of parasitic resonator
Authors: Luo Yu , Chu Qing‐Xin , Bornemann Jens 
Published: November 2016

ABSTRACTA printed‐circuit differential‐fed Yagi–Uda antenna is presented that features enhanced bandwidth by employing a parasitic quarter‐wavelength coplanar stripline (CPS) resonator which adds one more resonant mode within the operating bandwidth. The proposed antenna is designed, fabricated and measured. Experimental results are in good agreement with simulations. In the band of 2.27–2.58 GHz, the return loss is better than 10 dB and the gain better than 6 dBi. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:156–159, 2017
Design and performance analysis of pattern reconfigurable MIMO antennas for mobile smartphones
Authors: Shoaib Sultan , Shoaib Nosherwan , Shoaib Imran , Chen Xiaodong 
Published: November 2016

ABSTRACTThis paper presents compact pattern reconfigurable antennas for mobile handsets in MIMO configuration. Each antenna of the MIMO configuration being coupled fed monopole in meandered form is capable of covering several cellular frequency bands in the range of 1.75–2.67 GHz including 4G‐LTE, 2G‐GSM, 3G‐UMTS, and WLAN. The MIMO antennas are printed diagonally at the left and right no‐ground portions on the top layer of the substrate to enhance the isolation performance. The substrate used is FR‐4 with relative permittivity of 4.35 and loss tangent of 0.02. The volume of the substrate is 120 × 65 × 1.6 mm3 with each antenna occupying an area of 26.5 × 14.5 mm2. The pattern reconfigurability is achieved by connecting and disconnecting a 4.5 × 2 mm2 metallic strip using the p‐i‐n diode switch. The antennas are pattern reconfigurable in the frequency range of 1.9–2.1 GHz. The isolation achieved is better than 16 dB over all the frequency bands covered by each antenna. A prototype has been fabricated and tested. The simulated and measured results show a good performance of the MIMO antennas. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:148–156, 2017
Compact octa‐band monopole antenna with independently tuning for WWAN/LTE mobile phones
Authors: Huang Daiwei , Du Zhengwei , Wang Yan 
Published: November 2016

ABSTRACTA compact octa‐band monopole antenna with the size of 70 mm × 8 mm × 4.8 mm for WWAN/LTE mobile phones is proposed in this letter. It consists of two branches and a match circuit. The two branches radiate at the lower and higher bands, respectively. Thus, the lower and higher bands can be tuned independently. The match circuit composed of a shorting strip which is used as a distributed inductance and a lumped capacitance of 3 pF that can make the lower band matched and enhance the bandwidth. The fascinating merits of the proposed antenna are that the lower and higher bands can be tuned independently and the non‐ground portion height is only 8 mm. A prototype is manufactured and measured. The measured −6 dB impedance bandwidths are 313 MHz (0.697–1.01 GHz) and 1.66 GHz (1.59–3.25 GHz) at the lower and higher bands, respectively, which can cover the LTE700, GSM850, GSM900, GSM1800, GSM1900, UMTS, LTE2300, and LTE2500 bands. The measured radiation patterns, gain, and efficiency are presented. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:208–214, 2017
Ultra‐compact switchable microstrip band‐pass filter–low‐pass filter with improved characteristics
Authors: Kumar Singh Prashant , Kumar Tiwary Anjini , Gupta Nisha 
Published: November 2016

ABSTRACTA novel, ultra‐compact switchable microstrip band‐pass filter–low‐pass filter (BPF–LPF) showing wide stop band and good attenuation characteristics is proposed in this paper. Both BPF and LPF operation utilizes a common geometrical filter section, and individual filter operation is realized by means of the switches operated in “ON” or “OFF” mode. The proposed filter is designed for the dual mode BPF for wireless local area network (5.15–5.35 GHz) application with all four switches in OFF condition and for the LPF at 3 GHz cut‐off frequency with all switches in ON condition. The insertion loss (S21) in the stop band region is below −20 dB extending up to 12 GHz for both the filters. The proposed reconfigurable filter is ultra‐compact having the circuit size of only 5.952 mm × 8 mm = 47.616 mm2. The simulation result is validated experimentally. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:197–201, 2017
Particle swarm optimization for numerical bifurcation analysis in computational inelasticity
Authors: Lai Zhengshou , Chen Qiushi 
Published: November 2016

SummaryAn efficient and robust algorithm to numerically detect material instability or bifurcation is of great importance to the understanding and simulation of material failure in computational and applied mechanics. In this work, an intelligence optimizer, termed the particle swarm optimization, is introduced to the numerical solution of material bifurcation problem consisting of finding the bifurcation time as well as the corresponding bifurcation directions. The detection of material bifurcation is approached as a constrained minimization problem where the determinant of the acoustic tensor is minimized. The performance of the particle swarm optimization method is tested through numerical bifurcation analysis on both small and finite deformation material models in computational inelasticity with increasing complexity. Compared with conventional numerical approaches to detect material bifurcation, the proposed method demonstrates superior performance in terms of both computational efficiency and robustness. Copyright © 2016 John Wiley & Sons, Ltd.
On an Uzawa smoother in multigrid for poroelasticity equations
Authors: Luo P. , Rodrigo C. , Gaspar F. J. , Oosterlee C. W. 
Published: November 2016

SummaryA poroelastic saturated medium can be modeled by means of Biot's theory of consolidation. It describes the time‐dependent interaction between the deformation of porous material and the fluid flow inside of it. Here, for the efficient solution of the poroelastic equations, a multigrid method is employed with an Uzawa‐type iteration as the smoother. The Uzawa smoother is an equation‐wise procedure. It shall be interpreted as a combination of the symmetric Gauss‐Seidel smoothing for displacements, together with a Richardson iteration for the Schur complement in the pressure field. The Richardson iteration involves a relaxation parameter which affects the convergence speed, and has to be carefully determined. The analysis of the smoother is based on the framework of local Fourier analysis (LFA) and it allows us to provide an analytic bound of the smoothing factor of the Uzawa smoother as well as an optimal value of the relaxation parameter. Numerical experiments show that our upper bound provides a satisfactory estimate of the exact smoothing factor, and the selected relaxation parameter is optimal. In order to improve the convergence performance, the acceleration of multigrid by iterant recombination is taken into account. Numerical results confirm the efficiency and robustness of the acceleration scheme.
Response sensitivity of material and geometric nonlinear force‐based Timoshenko frame elements
Authors: Scott Michael H. , Jafari Azad Vahid 
Published: November 2016

SummaryResponse sensitivity is an essential component to understanding the complexity of material and geometric nonlinear finite element formulations of structural response. The direct differentiation method (DDM), a versatile approach to computing response sensitivity, requires differentiation of the equations that govern the state determination of an element and it produces accurate and efficient results. The DDM is applied to a force‐based element formulation that utilizes curvature‐shear‐based displacement interpolation (CSBDI) in its state determination for material and geometric nonlinearity in the basic system of the element. The response sensitivity equations are verified against finite difference computations, and a detailed example shows the effect of parameters that control flexure–shear interaction for a stress resultant plasticity model. The developed equations make the CSBDI force‐based element available for gradient‐based applications such as reliability and optimization where efficient computation of response sensitivities is necessary for convergence of gradient‐based search algorithms. Copyright © 2016 John Wiley & Sons, Ltd.
NMR study of the comonomer effect in metallocene poly(propylene‐co‐1‐pentene) copolymers synthesized at low temperature
Authors: García‐Peñas Alberto , Martínez Carmen , Cerrada María L. , Pérez Ernesto , Gómez‐Elvira José M. 
Published: November 2016

ABSTRACTThe influence of the comonomer in the synthesis of poly(propylene‐co−1‐pentene) copolymers, with rac‐(dimethylsilylbis(1‐indenyl))ZrCl2/Methylaluminoxane at low temperature, has been studied. Changes in the catalyst activity and molecular weight have been analyzed as a function of copolymer composition, and associated with both content and nature of chain defects. The thorough characterization of chain‐end double bonds by means of the 1H NMR technique highlights the particular chain termination pathway, which underlies the so‐called comonomer effect. A specific termination mechanism is proposed based on the preferential regio‐irregular interaction of the active site with 1‐pentene molecules, instead of the one related to the β‐H atom of the last regular inserted unit, either propene or 1‐pentene. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 843–854
Concise Review: Stem Cell-Based Treatment of Pelizaeus-Merzbacher Disease
Authors: Osorio M. Joana , Rowitch David H. , Tesar Paul , Wernig Marius , Windrem Martha S. , Goldman Steven A. 
Published: November 2016

Abstract
Pelizaeus-Merzbacher disease (PMD) is an X-linked disorder caused by mutation in the proteolipid protein-1 (PLP1) gene, which encodes the proteolipid protein of myelinating oligodendroglia. PMD exhibits phenotypic variability that reflects its considerable genotypic heterogeneity, but all forms of the disease result in central hypomyelination, associated in most cases with early neurological dysfunction, progressive deterioration, and ultimately death. PMD may present as a connatal, classic and transitional forms, or as the less severe spastic paraplegia type 2 and PLP-null phenotypes. These disorders are most often associated with duplications of the PLP1 gene, but can also be caused by coding and noncoding point mutations as well as full or partial deletion of the gene. A number of genetically-distinct but phenotypically-similar disorders of hypomyelination exist which, like PMD, lack any effective therapy. Yet as relatively pure CNS hypomyelinating disorders, with limited involvement of the PNS and relatively little attendant neuronal pathology, PMD and similar hypomyelinating disorders are attractive therapeutic targets for neural stem cell and glial progenitor cell transplantation, efforts at which are now underway in a number of research centers.
The cellular and molecular basis of cnidarian neurogenesis
Authors: Rentzsch Fabian , Layden Michael , Manuel Michaël 
Published: November 2016

Neurogenesis initiates during early development and it continues through later developmental stages and in adult animals to enable expansion, remodeling, and homeostasis of the nervous system. The generation of nerve cells has been analyzed in detail in few bilaterian model organisms, leaving open many questions about the evolution of this process. As the sister group to bilaterians, cnidarians occupy an informative phylogenetic position to address the early evolution of cellular and molecular aspects of neurogenesis and to understand common principles of neural development. Here we review studies in several cnidarian model systems that have revealed significant similarities and interesting differences compared to neurogenesis in bilaterian species, and between different cnidarian taxa. Cnidarian neurogenesis is currently best understood in the sea anemone Nematostella vectensis, where it includes epithelial neural progenitor cells that express transcription factors of the soxB and atonal families. Notch signaling regulates the number of these neural progenitor cells, achaete‐scute and dmrt genes are required for their further development and Wnt and BMP signaling appear to be involved in the patterning of the nervous system. In contrast to many vertebrates and Drosophila, cnidarians have a high capacity to generate neurons throughout their lifetime and during regeneration. Utilizing this feature of cnidarian biology will likely allow gaining new insights into the similarities and differences of embryonic and regenerative neurogenesis. The use of different cnidarian model systems and their expanding experimental toolkits will thus continue to provide a better understanding of evolutionary and developmental aspects of nervous system formation. WIREs Dev Biol 2017, 6:e257. doi: 10.1002/wdev.257This article is categorized under:

Gene Expression and Transcriptional Hierarchies > Cellular Differentiation
Signaling Pathways > Cell Fate Signaling
Comparative Development and Evolution > Organ System Comparisons Between Species
Current progress on microRNAs‐based therapeutics in neurodegenerative diseases
Authors: Pereira Patrícia , Queiroz João A. , Figueiras Ana , Sousa Fani 
Published: November 2016

MicroRNAs (miRNAs)‐based therapy has recently emerged as a promising strategy in the treatments of neurodegenerative diseases. Thus, in this review, the most recent and important challenges and advances on the development of miRNA therapeutics for brain targeting are discussed. In particular, this review highlights current knowledge and progress in the field of manufacturing, recovery, isolation, purification, and analysis of these therapeutic oligonucleotides. Finally, the available miRNA delivery systems are reviewed and an analysis is presented in what concerns to the current challenges that have to be addressed to ensure their specificity and efficacy. Overall, it is intended to provide a perspective on the future of miRNA‐based therapeutics, focusing the biotechnological approach to obtain miRNAs. WIREs RNA 2017, 8:e1409. doi: 10.1002/wrna.1409This article is categorized under:

RNA Processing > Processing of Small RNAs
Regulatory RNAs/RNAi/Riboswitches > Regulatory RNAs
RNA in Disease and Development > RNA in Disease
Phylogeny-guided (meta)genome mining approach for the targeted discovery of new microbial natural products
Authors: Kang Hahk-Soo 
Published: November 2016

AbstractGenomics-based methods are now commonplace in natural products research. A phylogeny-guided mining approach provides a means to quickly screen a large number of microbial genomes or metagenomes in search of new biosynthetic gene clusters of interest. In this approach, biosynthetic genes serve as molecular markers, and phylogenetic trees built with known and unknown marker gene sequences are used to quickly prioritize biosynthetic gene clusters for their metabolites characterization. An increase in the use of this approach has been observed for the last couple of years along with the emergence of low cost sequencing technologies. The aim of this review is to discuss the basic concept of a phylogeny-guided mining approach, and also to provide examples in which this approach was successfully applied to discover new natural products from microbial genomes and metagenomes. I believe that the phylogeny-guided mining approach will continue to play an important role in genomics-based natural products research.
Soil water extraction patterns of lucerne grown on stony soils
Authors: Sim Richard E. , Brown Hamish E. , Teixeira Edmar I. , Moot Derrick J. 
Published: November 2016

Abstract

Background and aims
Lucerne (Medicago sativa L.) is often grown under water-limited production conditions due to its capacity to extract water from deep soil layers through an extensive taproot system. These soils often contain stones which cause the roots to become unevenly distributed due to displacement by rock fragments. To improve the estimation of water use by lucerne grown in stony soils, we investigated the temporal pattern of water supply and demand, and how this influences crop growth.

Methods
Naturally occurring stones in the silt loam soil profile were used to reduce the plant available water capacity for three lucerne crops. The Monteith model was fitted against observed soil water to obtain estimates of the extraction rate constant (kl, day−1) and extraction front velocity (EFV, mm day−1) of lucerne roots. Crop water demand was represented by transpiration losses driven by intercepted solar radiation based on the “canopy conductance” approach.

Results
The Monteith model described the pattern of water extraction for lucerne grown on stony soils. However, a single, constant kl and EFV were inappropriate for characterising water extraction. The main physiological responses to water stress were (i) a reduction in canopy conductance, (ii) a reduction in canopy expansion and (iii) the rearrangement of leaves into a more vertical position.

Conclusion
This study validated frameworks to quantify lucerne water extraction and transpiration demand which can be used to improve the estimation of water use by lucerne crops.
Unsaturated shear strength properties of a compacted expansive soil from Regina, Canada
Authors: Chowdhury Rashedul H. , Azam Shahid 
Published: November 2016

AbstractThe main objective of this research was to investigate the unsaturated shear strength properties of the compacted expansive soil from Regina (Saskatchewan, Canada). Laboratory investigations on a typical expansive clay (liquid limit of 77% and plastic limit of 27%) were conducted using both saturated and unsaturated samples. Results indicated that the SWCC had one AEV of 10 kPa forwandθand two AEVs forS: 10 and 7000 kPa due to drainage through inter-clod pores and soil matrix, respectively. Most of the shrinkage occurred aroundS ≈ 80%, whereas desaturation before and after this value was associated with small changes in void ratio. Likewise, the peak stress on the dry side of optimum along with the initial gradient of the stress-displacement curve of up to 250 kPa and 13,350 kPa/mm, respectively, decreased to 170 kPa and 5670 kPa/mm on the wet side of optimum. The variation in cohesion followed the compaction curve and increased from 24 kPa on dry side to 65 kPa at optimum and then decreased to 33 kPa on wet side. The friction angle followed an L-shaped trend and decreased from 44° on dry side to 29° at optimum and to 27° on wet side. Finally, the S-shapedϕbcurve was in agreement with compaction characteristics and the SWCC. Theϕbcurve comprised 1° increase on dry side (and approaching residual suction), 12° increase around optimum (between AEV and residual suction), and 2° increase on wet side that tended to approach ϕ near saturation.