bluuebunny/crossref_metadata_2025_split huggingface dataset:
A bioinspired hybrid optimization algorithm for designing broadband frequency selective surfaces
Authors: de Araújo Wellington C. , Lins Hertz W. C. , D'Assunção Adaildo G. , Medeiros Joêmia L. G. , D'Assunção Adaildo G. 
Published: December 2013

ABSTRACTA hybrid optimization technique is used to synthesize frequency selective surface (FSS) structures composed of periodic arrays of integrated rings and dipole patch elements, printed on dielectric substrates, for microwave filtering applications. The optimization technique is based on the combination of genetic algorithms and neural networks. This hybrid optimization technique is used to determine specific values for the resonant frequency and bandwidth from variations of the FSS structural parameters, such as patch element and periodic array dimensions. The synthesized FSS structure is also analyzed using a fast and accurate wave concept iterative procedure for comparison purpose. Thereafter, prototypes are built and measured. A good agreement is observed between simulated and measured results. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:329–333, 2014
Temperature insensitive fiber optical displacement sensors based on double fiber Bragg gratings
Authors: Jiang Ming , Cui Liuzhu , Liu Rong 
Published: December 2013

ABSTRACTA temperature insensitive fiber optical displacement sensor based on double Bragg gratings is presented and experimentally demonstrated. The sensor is constructed by a trapezoid slid block and two isosceles cantilevered beams, and two fiber Bragg gratings (FBG) that are glued on the two beams. The displacement can be measured by interrogating the wavelength difference of the two FBGs, and the temperature dependence is greatly reduced. Experimental results show that a displacement sensitivity of 120 pm/mm and a temperature dependence of 2.1 pm/°C are achieved. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:304–306, 2014
A compact broadband spiral antenna for millimeter wave applications
Authors: Chernobrovkin Roman , Ivanchenko D. , Ivanchenko I. , Popenko N. , Pishikov V. 
Published: December 2013

ABSTRACTThe planar spiral antenna being connected with the waveguide and operating in the long‐wave region of the millimeter range is proposed. The antenna has the bandwidth of 6 GHz and the axial ration which does not exceed −3dB in the frequency band 32–36.5 GHz. The radiation pattern shape is slightly changed within the operational frequency band. The results of simulations and experimental data are in good agreement. The nature of radiation pattern and axial ration changing within the operational frequency band is explained from the analysis of near‐field distributions measured at two orthogonal polarizations. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:293–297, 2014
A tunable photonic RF phase shifter using single semiconductor optical amplifier
Authors: Chen Han , Sun Mingming , Ding Yi , Sun Xiaohan 
Published: December 2013

ABSTRACTA continuously tunable linear radio frequency phase shifter based on polarization interference in single semiconductor optical amplifier is presented, and the theoretical fundamentals of the design are explained. A prototype of the phase shifter with 10‐GHz bandwidth and far beyond 360° tuning range is experimentally demonstrated. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:340–343, 2014
A pneumatically controlled capacitive switch
Authors: Wu Billy , Okoniewski Michal , Hayden Chris 
Published: December 2013

ABSTRACTThe design and fabrication process of a unique pneumatically controlled capacitive switch is described. The switch, developed for reconfigurable antennas, presents a low‐loss alternative switching mechanism, and avoids the issue of a complicated biasing layout associated with electrostatic actuation in the conducting layer. The closed state of the switch is created by a movable copper‐coated solid slug that bridges a gap in a microstrip line with capacitive coupling. The basis of the switching mechanism is pressurized air causing the physical displacement of the slug inside a confining dielectric channel. Repeatable switching between open and closed states by pneumatically controlling the position of the slug was demonstrated with the fabricated switch. The minimum pressure required to move the slug was measured. This switch was measured from 0.5 to 15 GHz using a Thru‐Reflect‐Line calibration to de‐embed the coax‐to‐microstrip transitions. Insertion loss of 0.2 dB and isolation of 25 dB have been achieved at 5 GHz. The successful fabrication and measurement of the switch demonstrates the viability of applying this technology in reconfigurable antenna designs. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:489–493, 2014
Plasmonic narrow band pass filter based on planner Lange coupler
Authors: Andrawis Robert 
Published: December 2013

ABSTRACTIn this article, a new plasmonic narrow band pass filter is introduced and optimized versus different dimensions. The filter is based on Lange coupler with open circuit termination in two of its ports. The results are validated by two full‐wave solvers. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:446–448, 2014
A compact band‐notched ultrawideband dielectric‐loaded antenna
Authors: Tseng Ching‐Fang , Lu Shu‐Cheng 
Published: December 2013

ABSTRACTA compact ultrawideband (UWB) dielectric‐loaded antenna with band notched characteristics is presented. The antenna consists of the circular metal radiation patch fed by a 50‐Ω microstrip transmission line and a rectangular ground plane with cutting a notch to achieve UWB application. By etching a modified U‐shaped slot in the radiating patch and properly tuning its location and form, band rejected filtering properties in the WiMAX/WLAN bands can be achieved easily. The compact size of the proposed DRA can be reduced to 14.5 × 29 mm2 using a dielectric resonator (DR) above the modified circular radiation patch and possess band‐notched UWB characteristics. A good agreement has been obtained between simulation and measurement and it has good omnidirectional radiation patterns in H‐plane. Especially, the proposed band‐notched UWB loaded with GYA DR has excellent surrounding environment temperature stability. Base on these desirable features of the proposed band‐notched UWB dielectric‐loaded antenna, it is shown that it is a good candidate for various UWB applications. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:456–462, 2014
Microstrip multistopband filter based on prefractal space‐filling curve
Authors: Caramanica Federico 
Published: December 2013

ABSTRACTIn this letter, a method for the design of miniaturized multistopband filters is presented. This methodology exploits multiple resonance behavior of a small‐size prefractal geometries. The considered fractal structures based on space‐filling curve geometry and then, after recasting the design problem as an optimization one by defining a suitable cost function, is optimized by an unsupervised procedure, the gravitational search algorithm, which is a recent and interesting stochastic optimization method. To assess the effectiveness of this approach, a filter with three stopbands has been designed, numerically assessed, and realized. The obtained results are in good agreement with the numerical simulations and this confirms the capabilities of the proposed method as a microwave Computer Aided Design (CAD) tool. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:450–455, 2014
Frequency selective surface with switchable polarization
Authors: Du Guohong , Yu Chengyang , Liu Changjun 
Published: December 2013

ABSTRACTThis article presents a novel frequency selective surface (FSS) with switchable polarization, which is realized using the improved cross slots with embedded strips and isolated island structure. The transmission characteristics of FSS unit cell for both horizontal polarization and vertical polarization are simulated with CST. And a FSS made of an array of 20 × 20 cells is implemented on the substrate Rogers RO4003. The experiment results show that the proposed FSS can obtain polarization switching through short and open circuits for X‐band application. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:515–518, 2014
Design of an ultrawideband conformal metal antenna
Authors: Mondal S. , Sarkar P. P. 
Published: December 2013

ABSTRACTIn this article, a novel design of volcano smoke antenna is proposed as an ultrawideband (UWB) conformal antenna. The radiating element and CPW feed line are in the same plane that makes the antenna completely planar. The proposed planar metal antenna is bent on a cylindrical surface, and the characteristics of the antenna for different bent conditions are studied. This study shows no significant change of reflection coefficient and radiation pattern characteristics of the bent antenna compared to that of flat position. The impedance bandwidth for S11 < −10 dB of the bent antenna covers the UWB (3.1–10.6 GHz). Variation of absolute gain and group delay of the antenna under flat and bent conditions are shown in this article. The measured reflection coefficient agrees with the simulated results. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:430–434, 2014
Quantitative cerebral blood flow with bolus tracking perfusion MRI: Measurements in porcine model and comparison with PET
Authors: Kellner Elias , Mix Michael , Reisert Marco , Förster Katharina , Nguyen‐Thanh Thao , Splitthoff Daniel Nico , Gall Peter , Kiselev Valerij G. , Mader Irina 
Published: December 2013

PurposeWe recently presented a method for the quantitative measurement of the arterial input function which allows for determination of absolute cerebral blood flow (CBF) values without adjustable parameters. The aim of the present work is to estimate absolute CBF values by using this new technique and to compare it with the gold standard for cerebral perfusion,
positron emission tomography.MethodsPigs (13) were comparatively investigated by each method performing multiple measurement runs. The reproducibility of both methods was assessed by a voxel‐wise correlation of repeated measurements. An intersubject evaluation was performed on median whole‐brain CBF estimates.ResultsThe mean CBF (MRI) was
for gray matter, the mean CBF (positron emission tomography) was
for gray and white matter. The reproducibility for MRI correlated with r = 0.85 and
, for positron emission tomography with r = 0.76 and
. The correlation for the median whole‐brain CBF in MRI and positron emission tomography was r = 0.60 and P = 0.04.ConclusionsThe proposed method allows for determination of quantitative CBF without normalization factors. The relatively low estimates of absolute CBF most likely results from the higher age of the pigs as compared to other studies. The intermediate correlation between both methods is caused by physiological intraindividual fluctuations of the CBF and by a limited reproducibility of both methods. Magn Reson Med 72:1723–1734, 2014. © 2013 Wiley Periodicals, Inc.
Can the adrenergic system be implicated in the pathophysiology of bladder pain syndrome/interstitial cystitis? A clinical and experimental study
Authors: Charrua Ana , Pinto Rui , Taylor Anna , Canelas André , Ribeiro‐da‐Silva Alfredo , Cruz Célia D. , Birder Lori Ann , Cruz Francisco 
Published: December 2013

AbstractAimsTo evaluate sympathetic system activity in bladder pain syndrome/interstitial cystitis (BPS/IC) patients and to investigate if chronic adrenergic stimulation in intact rats induces BPS/IC‐like bladder modifications.MethodsClinical study—In BPS/IC patients and aged and body mass index matched volunteers TILT test was undertaken and catecholamines were measured in plasma and 24 hr urine samples. Experimental study—Phenylephrine was injected subcutaneously (14 days) to female Wistar rats. Pain behavior, spinal Fos expression, urinary spotting, number of fecal pellets expelled, frequency of reflex bladder contractions, and urothelial height were analyzed. Urothelium permeability was investigated by trypan blue staining. Immunoreactivity against caspase 3 and bax were studied in the urothelium and against alpha‐1‐adrenoreceptor and TRPV1 in suburothelial nerves. Mast cell number was determined in the sub‐urothelium. In rats with lipopolysaccharide‐induced cystitis, urinary catecholamines, and Vesicular Monoamine Transporter 2 (VMAT2) expression in bladder nerves were analyzed.ResultsThe TILT test showed an increase of sympathetic activity. Noradrenaline levels in blood at resting conditions and in 24‐hr urine samples were higher in BPS/IC patients. Phenylephrine administration increased visceral pain, spinal Fos expression, bladder reflex activity, urinary spotting and the number of expelled fecal pellets. The mucosa showed urothelial thinning and increased immunoreactivity for caspase 3 and bax. Trypan blue staining was only observed in phenylephrine treated animals. Suburothelial nerves co‐expressed alpha1 and TRPV1. Mastocytosis was present in the suburothelium. Cystitis increased sympathetic nerve density and urinary noradrenaline levels.ConclusionsExcessive adrenergic stimulation of the bladder may contribute to the pathophysiological mechanisms of BPS/IC. Neurourol. Urodynam. 34:489–496, 2015. © 2013 Wiley Periodicals, Inc.
Apparent diffusion coefficient measurements of the fetal brain during the third trimester of pregnancy: how reliable are they in clinical practice?
Authors: Sartor Agnès , Arthurs Owen , Alberti Corinne , Belarbi Nadia , Tilea Bogdana , Boizeau Priscilla , Oury Jean‐Francois , Elmaleh‐Berges Monique , Gressens Pierre , Sebag Guy , Alison Marianne 
Published: December 2013

ABSTRACTObjectiveThe objective of this study was to determine the reproducibility, the inter‐hemispheric difference and the reference apparent diffusion coefficient (ADC) values of the fetal brain according to gestational age.MethodOne hundred and one normal fetal brain (29.4–38.4 weeks) were analysed with diffusion‐weighted MR imaging. ADC was measured in frontal white matter (FWM), occipital white matter (OWM), centrum semi‐ovale (CSO), basal ganglia (BG), cerebellar hemisphere (CBM) and pons. ADC ratios (fronto‐occipital, fronto‐cerebellar and occipito‐cerebellar) were calculated. Inter‐observer reproducibility was assessed on 27 studies, using intra‐class correlation coefficient and Bland–Altman plot. Inter‐hemispheric difference was evaluated with Bland–Altman plot. Gestation‐specific reference intervals were estimated for each brain region.ResultsInter‐observer bias was near zero. Limits of agreement (LOA) were clinically acceptable (−0.17; 0.20 to −0.38; 0.31 × 10−3 mm2/s) for all brain regions except for CSO and pons. Inter‐hemispheric bias was near zero. Smallest LOA were for FWM (±0.09 mm2/s) and BG (±0.019 mm2/s). ADC values decreased, whereas ADC ratio increased with gestational age, reflecting normal maturation. Fronto‐occipital, fronto‐cerebellar and occipito‐cerebellar ratios were consistently above 0.8, 1 and 1, respectively.ConclusionThe fetal brain regions with the highest reproducibility and smallest inter‐hemispheric differences are the frontal, occipital, cerebellar white matter and BG. ADC ratio could be useful to assess differential temporo‐spatial maturation. © 2013 John Wiley & Sons, Ltd.
Effect of alkane chain segment length on the crystallization kinetics of nylon 1010, 1013 and 1014
Authors: Zhang Long , Zhang Xingyuan , Wu Lijun , Deng Yipeng , Liu Ruijie 
Published: December 2013

AbstractIsothermal and non‐isothermal crystallization kinetics of long alkane chain segment nylon 1010, 1013 and 1014 were investigated by differential scanning calorimetry. The commonly used Avrami equation and that modified by Jeziorny were employed to fit the isothermal and non‐isothermal crystallizations of nylon 1010, 1013 and 1014, respectively. It was found that the crystallization rate of nylon with a longer alkane chain segment was slower than that of nylon with a shorter one at a given cooling rate. The activation energies for the isothermal and non‐isothermal crystallizations determined by the Arrhenius and the Kissinger methods, respectively, decreased with increase of the alkane chain segment length of nylon 1010, 1013 and 1014. Furthermore, the activation energy of the non‐isothermal crystallization process of these nylons, determined by the isoconversional methods of Flynn and Wall and Ozawa, was found to be a decreasing function of the relative degree of crystallinity. © 2014 Society of Chemical Industry
Synthesis and properties of new polyamide/multiwalled carbon nanotube nanocomposites containing a pyridine group
Authors: Shabanian Meisam , Basaki Nemat , Khonakdar Hossein Ali , Kianipour Shokat , Wagenknecht Udo 
Published: December 2013

AbstractThe effects of multiwalled carbon nanotubes (MWCNTs) on the thermal properties and flame retardancy of a new polyamide (PA) derived from glutaric acid and aromatic diamine were investigated in this work. The synthesized PA containing pyridine and trialkylamine groups was characterized by 1H NMR and SEC. The PA unit structure was geometrically optimized at the B3LYP/6‐311++G(d, p) level of theory. PA showed a glass transition temperature of 151 ºC. PA nanocomposites containing two different amounts of MWCNTs were prepared via the solution intercalation technique with the solvent N,N‐dimethylacetamide. Transmission electron microscopy showed that MWCNTs were exfoliated in the polymer matrix, resulting in well‐dispersed morphologies at 3 wt% MWCNT content. The redox behaviors of PA and the nanocomposites were examined using cyclic voltammetry (CV). PA showed a reversible oxidation process in the CV scan. Thermal and flammability properties of the nanocomposites were studied by TGA in nitrogen and air, DSC and with a microscale combustion calorimeter. The TGA results showed that the addition of MWCNTs resulted in a substantial increase in the thermal stability and char yields of the nanocomposites compared with neat PA. The heat release rate and total heat release were significantly reduced in the presence of MWCNTs. © 2013 Society of Chemical Industry
MALDI imaging and in‐source decay for top‐down characterization of glioblastoma
Authors: Ait‐Belkacem Rima , Berenguer Caroline , Villard Claude , Ouafik L'Houcine , Figarella‐Branger Dominique , Chinot Olivier , Lafitte Daniel 
Published: December 2013

Glioblastoma multiforme is one of the most common intracranial tumors encountered in adults. This tumor of very poor prognosis is associated with a median survival rate of approximately 14 months. One of the major issues to better understand the biology of these tumors and to optimize the therapy is to obtain the molecular structure of glioblastoma. MALDI molecular imaging enables location of molecules in tissues without labeling. However, molecular identification in situ is not an easy task. In this paper, we used MALDI imaging coupled to in‐source decay to characterize markers of this pathology. We provided MALDI molecular images up to 30 μm spatial resolution of mouse brain tissue sections. MALDI images showed the heterogeneity of the glioblastoma. In the various zones and at various development stages of the tumor, using our top‐down strategy, we identified several proteins. These proteins play key roles in tumorigenesis. Particular attention was given to the necrotic area with characterization of hemorrhage, one of the most important poor prognosis factors in glioblastoma.
The versatility of the αβ T‐cell antigen receptor
Authors: Bhati Mugdha , Cole David K. , McCluskey James , Sewell Andrew K. , Rossjohn Jamie 
Published: December 2013

AbstractThe T‐cell antigen receptor is a heterodimeric αβ protein (TCR) expressed on the surface of T‐lymphocytes, with each chain of the TCR comprising three complementarity‐determining regions (CDRs) that collectively form the antigen‐binding site. Unlike antibodies, which are closely related proteins that recognize intact protein antigens, TCRs classically bind, via their CDR loops, to peptides (p) that are presented by molecules of the major histocompatibility complex (MHC). This TCR‐pMHC interaction is crucially important in cell‐mediated immunity, with the specificity in the cellular immune response being attributable to MHC polymorphism, an extensive TCR repertoire and a variable peptide cargo. The ensuing structural and biophysical studies within the TCR‐pMHC axis have been highly informative in understanding the fundamental events that underpin protective immunity and dysfunctional T‐cell responses that occur during autoimmunity. In addition, TCRs can recognize the CD1 family, a family of MHC‐related molecules that instead of presenting peptides are ideally suited to bind lipid‐based antigens. Structural studies within the CD1‐lipid antigen system are beginning to inform us how lipid antigens are specifically presented by CD1, and how such CD1‐lipid antigen complexes are recognized by the TCR. Moreover, it has recently been shown that certain TCRs can bind to vitamin B based metabolites that are bound to an MHC‐like molecule termed MR1. Thus, TCRs can recognize peptides, lipids, and small molecule metabolites, and here we review the basic principles underpinning this versatile and fascinating receptor recognition system that is vital to a host's survival.
Comparative susceptibility of Bemisia tabaci to imidacloprid in field‐ and laboratory‐based bioassays
Authors: Castle Steven J , Merten Paul , Prabhaker Nilima 
Published: December 2013

AbstractBACKGROUNDBemisia tabaci biotype B is a resistance‐prone pest of protected and open agriculture. Systemic uptake bioassays used in resistance monitoring programs have provided important information on susceptibility to neonicotinoid insecticides, but have remained decoupled from field performance. Simultaneous bioassays conducted in field and laboratory settings were compared and related to concentrations of imidacloprid in plant tissue for clearer interpretation of resistance monitoring data.RESULTSMean mortalities of adult whiteflies confined on cantaloupe leaves field‐treated with three rates of imidacloprid did not exceed 40% in two trials. In contrast, laboratory bioassays conducted on different subsets of the same whitefly populations yielded concentration–response curves suggestive of susceptibility to imidacloprid in five populations (LC50 values from 1.02 to 6.4) relative to a sixth population (LC50 = 13.8). In the field, densities of eggs and nymphs were significantly lower on the imidacloprid‐treated cantaloupes compared with the untreated control, but the margin of control was greater in 2006 than in 2007. The potential impact of imidacloprid on whitefly eggs was explored in a greenhouse test that showed egg mortality occurring in both early (one‐day‐old) and late (three‐day‐old) eggs on cotton leaves systemically treated with imidacloprid. Quantification of imidacloprid residues in cotton leaves used routinely in systemic uptake bioassays revealed concentrations that greatly exceeded concentrations found in the field‐treated cantaloupe leaves, at least at the three highest solution concentrations used for uptake.CONCLUSIONSystemic uptake bioassays have been widely used for monitoring B. tabaci resistance to imidacloprid, but without knowledge of imidacloprid concentrations that occur in test leaves relative to field concentrations. Higher mortality observed in systemic uptake bioassays relative to field‐treated cantaloupes in this study suggests that field rates of imidacloprid are only partially effective against B. tabaci adults, in contrast to systemic uptake bioassays that showed susceptibility to imidacloprid. The discrepancy between field‐ and laboratory‐based mortalities is probably due to extraordinarily high concentrations of imidacloprid that can occur in leaves of systemic uptake bioassays, potentially skewing perception of susceptibility to imidacloprid. Published 2013. This article is a U.S. Government work and is in the public domain in the USA