bluuebunny/crossref_metadata_2025 huggingface dataset:
Towards improved post‐processing of hydrologic forecast ensembles
Authors: Madadgar Shahrbanou , Moradkhani Hamid , Garen David
Published: September 2012

Forecast ensembles of hydrological and hydrometeorologial variables are prone to various uncertainties arising from climatology, model structure and parameters, and initial conditions at the forecast date. Post‐processing methods are usually applied to adjust the mean and variance of the ensemble without any knowledge about the uncertainty sources. This study initially addresses the drawbacks of a commonly used statistical technique, quantile mapping (QM), in bias correction of hydrologic forecasts. Then, an auxiliary variable, the failure index (γ), is proposed to estimate the ineffectiveness of the post‐processing method based on the agreement of adjusted forecasts with corresponding observations during an analysis period prior to the forecast date. An alternative post‐processor based on copula functions is then introduced such that marginal distributions of observations and model simulations are combined to create a multivariate joint distribution. A set of 2500 hypothetical forecast ensembles with parametric marginal distributions of simulated and observed variables are post‐processed with both QM and the proposed multivariate post‐processor. Deterministic forecast skills show that the proposed copula‐based post‐processing is more effective than the QM method in improving the forecasts. It is found that the performance of QM is highly correlated with the failure index, unlike the multivariate post‐processor. In probabilistic metrics, the proposed multivariate post‐processor generally outperforms QM. Further evaluation of techniques is conducted for river flow forecast of Sprague River basin in southern Oregon. Results show that the multivariate post‐processor performs better than the QM technique; it reduces the ensemble spread and is a more reliable approach for improving the forecast. Copyright © 2012 John Wiley & Sons, Ltd.
Neuronal and extraneuronal release of ATP and NAD+ in smooth muscle
Authors: Mutafova‐Yambolieva Violeta N.
Published: September 2012

Adenosine 5′‐triphosphate (ATP) and nicotinamide adenine dinucleotide (NAD+) are key intracellular constituents involved in energy transfer and redox homeostasis in the cell. ATP is also released in the extracellular space and in the past half century it has been assumed to be the purinergic neurotransmitter in many systems including smooth muscle. In some smooth muscles (i.e., the human urinary bladder detrusor muscle), ATP does appear to be primarily released from nerves upon action potential firings, but in other smooth muscles (i.e., the human large intestine), ATP does not mimic the endogenous purine neurotransmitter. It was recently found that NAD+, another ubiquitous intracellular adenine nucleotide, also follows a regulated release in neurosecretory cells, vascular and visceral smooth muscles, and the brain. In some cases, NAD+ fulfills presynaptic and postsynaptic criteria for a neurotransmitter better than ATP. Therefore, the purine hypothesis of neural regulation in smooth muscle is in need of reevaluation. This article will briefly review the current understanding of neuronal and extraneuronal release of purines in smooth muscle with emphasis on the roles of extracellular ATP and NAD+ and, further, will discuss more recent information about the likely involvement of multiple purines in smooth muscle neurotransmission. © 2012 IUBMB IUBMB Life, 2012
COMPARING ALTERNATIVE MODELS OF HETEROGENEITY IN CONSUMER CHOICE BEHAVIOR
Authors: Keane Michael , Wasi Nada
Published: September 2012

When modeling demand for differentiated products, it is vital to adequately capture consumer taste heterogeneity, But there is no clearly preferred approach. Here, we compare the performance of six alternative models. Currently, the most popular are mixed logit (MIXL), particularly the version with normal mixing (N‐MIXL), and latent class (LC), which assumes discrete consumer types. Recently, several alternative models have been developed. The 'generalized multinomial logit' (G‐MNL) extends N‐MIXL by allowing for heterogeneity in the logit scale coefficient. Scale heterogeneity logit (S‐MNL) is a special case of G‐MNL with scale heterogeneity only. The 'mixed‐mixed' logit (MM‐MNL) assumes a discrete mixture‐of‐normals heterogeneity distribution. Finally, one can modify N‐MIXL by imposing theoretical sign constraints on vertical attributes. We call this 'T‐MIXL'. We find that none of these models dominates the others, but G‐MNL, MM‐MNL and T‐MIXL typically outperform the popular N‐MIXL and LC models. Copyright © 2012 John Wiley & Sons, Ltd.
Delineating breast ductal carcinoma using combined dye‐enhanced wide‐field polarization imaging and optical coherence tomography
Authors: Patel Rakesh , Khan Ashraf , Kamionek Michal , Kandil Dina , Quinlan Robert , Yaroslavsky Anna N.
Published: September 2012

Intra‐operative delineation of breast cancer is a challenging problem. We used dye‐enhanced wide‐field polarization imaging for rapid demarcation of en face cancer margins and optical coherence tomography (OCT) for cross‐sectional evaluation. Ductal carcinoma specimens were stained with methylene blue. Wide‐field reflectance images were acquired at 440 and 640 nm. Wide‐field fluorescence images were excited at 640 nm and registered between 660 nm and 750 nm. OCT images were acquired using a 1310 nm swept‐source system. The results were validated against histopathology. Both imaging modalities provided diagnostic information on cancer margins. Combined OCT and wide‐field polarization imaging shows promise for intra‐operative detection of ductal breast carcinoma (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Global and local indices for characterizing biomolecular flexibility and rigidity
Authors: Pfleger Christopher , Radestock Sebastian , Schmidt Elena , Gohlke Holger
Published: September 2012

Understanding flexibility and rigidity characteristics of biomolecules is a prerequisite for understanding biomolecular structural stability and function. Computational methods have been implemented that directly characterize biomolecular flexibility and rigidity by constraint network analysis. For deriving maximal advantage from these analyses, their results need to be linked to biologically relevant characteristics of a structure. Such links are provided by global and local measures (“indices”) of biomolecular flexibility and rigidity. To date, more than 14 indices are available with sometimes overlapping or only vague definitions. We present concise definitions of these indices, analyze the relation between, and the scope and limitations of them, and compare their informative value. For this, we probe the structural stability of the calcium binding protein α‐lactalbumin as a showcase, both in the “ground state” and after perturbing the system by changing the network topology. In addition, we introduce three indices for the first time that extend the application domain of flexibility and rigidity analyses. The results allow us to provide guidelines for future studies suggesting which of these indices could best be used for analyzing, understanding, and quantifying structural features that are important for biomolecular stability and function. Finally, we make suggestions for proper index notations in future studies to prevent the misinterpretation and to facilitate the comparison of results obtained from flexibility and rigidity analyses. © 2012 Wiley Periodicals, Inc.
Trace analysis of polycyclic aromatic hydrocarbons using calixarene layered gold colloid film as substrates for surface‐enhanced Raman scattering
Authors: Shi Xiaofeng , Kwon Yong‐Hyok , Ma Jun , Zheng Ronger , Wang Chunyan , Kronfeldt H.‐D.
Published: September 2012

A surface‐enhanced Raman scattering (SERS) active substrate for the detection of polycyclic aromatic hydrocarbons (PAHs) was developed, which used 25, 27‐dimercaptoacetic acid‐26, 28‐dihydroxy‐4‐terbutyl calix[4]arene (DMCX) to functionalize a gold colloid film. This SERS‐active substrate prepared by self‐assembly method exhibits a high sensitivity, especially for the detection of PAHs. With the use of this SERS‐active substrate and with the application of the shifted excitation Raman difference spectroscopy (SERDS) technique, Raman signals of pyrene and anthracene in aqueous solutions at low concentration level (500 pM) can be obtained. Moreover, because PAHs are blocked from being directly adsorbed on gold colloid by DMCX and the photochemical reactions of adsorbates are avoided, the Raman bands of PAHs adsorbed on DMCX‐fuctionalized gold colloid film can be one‐to‐one correspondence with those of solid PAHs, and additionally, this SERS‐active substrate can be easily cleaned and reused. The obtained results demonstrate that the DMCX‐functionalized gold colloid films prepared by self‐assembly method have great potential to be developed to an in situ PAHs detection substrate. Copyright © 2012 John Wiley & Sons, Ltd.
Micro‐spectroscopic Raman investigation on the canvas oil painting ‘Rebecca at the well’ of Neapolitan anonymous
Authors: Cazzanelli E. , Platania E. , De Santo G. , Fasanella A. , Castriota M.
Published: September 2012

In this work, a micro‐Raman spectroscopic investigation was carried out in order to identify the pigments used in the canvas oil painting ‘Rebecca at the well’, which is preserved in MAON museum in Rende, southern Italy. The artwork's history is unknown, and no scientific investigation was performed on it before. Art historians believe that the painting was created in the XVIII century by an artist of the Neapolitan school. Raman spectra were collected by a Jobin Yvon micro‐Raman LABRAM apparatus, with a He–Ne laser (632.8 nm) as excitation source. The main original pigments were identified and modern pigments like yellow–orange chrome and phthalocyanine were also found, providing important information about the restoration works and the painting's history. Copyright © 2012 John Wiley & Sons, Ltd.
Analysis of global components in Ganoderma using liquid chromatography system with multiple columns and detectors
Authors: Qian Zhengming , Zhao Jing , Li Deqiang , Hu Dejun , Li Shaoping
Published: September 2012

In present study, a multiple columns and detectors liquid chromatography system for analysis of global components in traditional Chinese medicines was developed. The liquid chromatography system was consist of three columns, including size exclusion chromatography column, hydrophilic interaction chromatography column, and reversed phase chromato‐graphy column, and three detectors, such as diode array detector, evaporative light scattering detector, and mass spectrometry detector, based on column switching technique. The developed multiple columns and detectors liquid chromatography system was successfully applied to the analysis of global components, including macromolecular (polysaccharides), high (nucleosides and sugars)‐, and low (triterpenes)‐polarity small molecular compounds in Ganoderma, a well‐known Chinese medicinal mushroom. As a result, one macromolecular chromatographic peak was found in two Ganoderma species, 19 components were identified in Ganoderma lucidum (two sugars, three nucleosides, and 14 triterpenes), and four components (two sugars and two nucleosides) were identified in Ganoderma sinense. The developed multiple columns and detectors liquid chromatography system was helpful to understand comprehensive chemical characters in TCMs.
Influence of oil polarity and material combination on the tribological response of greases formulated with biodegradable oils and bentonite and highly dispersed silica acid
Authors: Fiedler M. , Sanchez R. , Kuhn E. , Franco J. M.
Published: September 2012

Different biodegradable lubricating greases formulated with esters of fatty acids, as base oils, and bentonite and highly dispersed silica acid, as thickener agents, were tribologically investigated in a nanotribometer and compared with polyalpha olefin greases with equal thickeners. Material combinations of steel ball on steel disc and sapphire ball on steel disc were used with different normal loads. Several friction and wear effects were found depending on the thickener and the base oil. The influence of grease components is also different in both material combinations evaluated. On the one hand, the base oil exerts a much higher impact on friction and wear in grease systems thickened with highly dispersed silica acid than in those thickened with bentonite. On the other hand, the latter reacts more sensitively to a change in material combination. Results were discussed and explained on the basis of polarity influences of the base oils and solid surfaces. Copyright © 2012 John Wiley & Sons, Ltd.
High‐Mechanical‐Strength Flame‐Retardant Nanocomposites Based on Novel Al(III)‐ and Zr(IV)‐Melamine Phosphates and Sulfates
Authors: Khalil Hazem , Gläsel Hans‐Jürgen , Buchmeiser Michael R.
Published: September 2012

Nanoparticles based on Al(III) and Zr(IV) melamine phosphate and sulfate, respectively, are prepared. Cone calorimeter measurements reveal that compared to an unfilled polyacrylate matrix the polyacrylate‐based nanocomposites containing the novel nanoparticles display significantly improved flame‐retardant properties as evidenced by the corresponding values for the peak heat release rate, the time‐to‐ignition, the values for the peak rate of heat release, the total heat evolved, the time to the CO peak and the CO yield. Concomitantly, the mechanical properties of the acrylate‐based composite coatings, i.e., the Martens and surface hardness, can also be significantly improved.

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Handling material discontinuities in a nonconforming generalized finite element method to solve wave propagation problems
Authors: Facco Werley G. , Silva Elson J. , Adriano Ricardo , Moura Alex S. , Lima Naísses Z.
Published: September 2012

To solve wave propagation problems over large domains composed by different media, many authors use the generalized finite element method (GFEM) with a geometrically conforming partition and plane wave enrichment.Such analysis is often accomplished by decomposing the entire domain into several subdomains and performing the analysis individually on each one. Then, the global analysis can be realized by using Lagrange multipliers to ensure the interface constraints. In this article, the GFEM with plane wave enrichment is extended to nonconforming discrete cases where the interface between the media can be handled as piecewise linear segments. Results for problems for which the analytical solution is known are presented to demonstrate the efficiency of the proposed technique. The convergence of the method is also presented as a function of the number of plane wave directions. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2709–2716, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27166
Two layer LTCC substrate integrated to rectangular waveguide transition and its application for millimeter‐wave LTCC characterization
Authors: Peters Florian D. L. , Denidni Tayeb A. , Tatu Serioja O.
Published: September 2012

In this letter, a new practical approach for designing a millimeter‐wave transition at 76.5 GHz from substrate integrated waveguide (SIW) line on two low temperature cofired ceramics (LTCC) layers to a rectangular waveguide is proposed. To the best of our knowledge, this is the first feasible planar solution to couple a top‐layer SIW exclusively. A very small probe is cut in both layers and inserted into a milled clearance in the metallic waveguide. Shrinkage tolerance is addressed in particular in our design procedure. In addition, multiple back‐to‐back transitions are milled into one fixture and applied to obtain the actual LTCC loss tangent and permittivity. The latter undergoes a strong dispersion. Fabricated circuits are optically analyzed and exhibit a higher shrinkage than expected. Simulation and measurement results show good performances in terms of reflection and transmission. With these features, the proposed solution is able to handle electrically large substrates of around 12λg. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2675–2679, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27167
Implementation and performance investigation of radio‐over‐fiber systems in wireless sensor networks
Authors: Lona Daniel G. , Assumpção Raphael M. , Branquinho Omar C. , Abbade Marcelo L.F. , Hernández‐Figueroa H. E. , Sodré Arismar Cerqueira
Published: September 2012

We report the performance investigation and implementation of four different radio‐over‐fiber (ROF) systems as backhaul for wireless sensor networks based on frequency shift keying modulation at 915 MHz. Its applicability was experimentally verified as a function of packet error rate, received signal strength indicator, and system reach. Furthermore, a performance noise analysis was carried out by taking into account the optical transmitter and receiver parameters, such as: equivalent input noise, noise figure, relative intensity noise, laser wavelength, and output power. The implementation of the proposed technical solution implies in a outstanding enhancement in the system reach, management, and flexibility. It has been achieved an improvement of 17.45 dB in the system performance by using high‐quality pieces of equipment of ROF technology. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2669–2675, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27168
Planar magneto‐dielectric metasubstrate for miniaturization of a microstrip patch antenna
Authors: Kim Dongho
Published: September 2012

A practically realizable planar‐type magneto‐dielectric metasubstrate to miniaturize a microstrip patch antenna is presented. The metasubstrate consists of two twisted metallic striplines, which provides inherently high effective permittivity (εeff) in a low frequency region together with strong magnetic resonance presenting high effective permeability (μeff) in a high frequency range. We suggest using the unusual properties of both high εeff and μeff of the proposed metasubstrate to reduce the overall antenna size, which has been proven to be effective in dropping an antenna resonant frequency to lower than a half of the original resonant frequency. Moreover, we have shown that a fictitious metasubstrate entirely composed of a homogeneous material filled with frequency‐dependent εeff and μeff also provides very similar antenna characteristics that are obtained using the fabricated inhomogeneous metasubstrate consisting of the twisted striplines. Therefore, we could confirm that the proposed metasubstrate indeed works as an effective material with high εeff and μeff just as we intended. Predicted results have shown good agreement with experimental data, which proves the validity of our approach. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2871–2874, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27172
PIFA with optimized ground shape and capacitive feeding for broadband applications
Authors: Bulla G. , Salles A. , Vuong T. P.
Published: September 2012

In this work, genetic algorithm is used to optimize the ground plane shape of planar inverted F antenna on FR‐4 substrate designed for broadband applications. Novel optimized antennas were presented. A relative bandwidth about 88% was obtained with the optimized antenna. With this procedure the total bandwidth increased more than 2.5 times relatively the total bandwidth of the not optimized antenna. However, the dimensions and the cost did not increase. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2842–2845, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27174
Low‐profile circularly polarized GNSS antenna
Authors: Silva Pimenta M. , Ferrero F. , Staraj R. , Ribero J.M.
Published: September 2012

In this article, we present a low‐profile and low cost antenna for GPS (L1–L2–L5), Galileo (E5–E1–E2), and Glonass (G1–G2) standard. This antenna is a dual‐feed planar patch antenna with four slots to achieve dual‐band operation. The radiating element is fed by a wideband 90° quadrature hybrid coupler to obtain circular polarization on the both bands. The quadrature feeding is achieved using a three‐branch‐line hybrid coupler. The return loss bandwidth of the system (S11 ≤ −10 dB) is 22% in the lower band and 14% in the upper one. The axial ratio (AR) bandwidth in broadside direction (AR= 3 dB) is 20% in the lower band and 11.3% at the upper one. The antenna gain is 6 and 8.4 dBi in the normal direction at the central frequency of 1.23 and 1.6 GHz, respectively. The total dimensions of the antenna are 170 mm2 with a thickness of 7.524 mm. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2811–2814, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27175
FDTD computational study of nanoplasmonic guiding structures for non‐paraxial spatial solitons
Authors: Lubin Zachary , Greene Jethro H. , Taflove Allen
Published: September 2012

Spatial solitons with beamwidths on the order of a wavelength are studied numerically in the context of their propagation paths being modified by planar nanoplasmonic structures.The prospect of such media in certain configurations used as soliton guiding devices is quantitatively assessed. A finite‐difference time‐domain model is used that incorporates a Kerr nonlinearity and linear dispersion, and solves for the vector components of the fields. A soliton effective beamsplitter, collimator, and dual‐beam waveguide are demonstrated. Interesting aspects of the reflection and transmission properties of gold films is discussed, including first‐time reporting of the Goos‐Hänchen effect in the nonlinear regime for a transverse magnetic, ultra‐narrow spatial soliton incident on a gold slab. The results provided herein are significant for nonlinear switching and routing applications toward future all‐optical computing devices. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2679–2684, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27182
A compact ultra‐wideband antenna with four band‐notched characteristics
Authors: Li Tong , Zhai Huiqing , Li Guihong , Li Long , Liang Changhong
Published: September 2012

A coplanar waveguide fed ultra‐wideband antenna with four band‐notched characteristics is proposed in this letter.Two split ring slots are etched on the patch and two inverted L‐shaped slots on the ground to generate four notched bands at 2.4, 3.5, 5.2, and 5.8 GHz, respectively, thus contribute good rejection of interference with WiFi (2.4 GHz), WiMax (3.5 GHz), and wireless local area network (5.2 GHz/5.8 GHz). The simulation and measurement show that the proposed antenna can guarantee a wide bandwidth from 2 to 12 GHz with stable gain and omnidirectional radiation pattern. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2862–2865, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27184
Left‐handed metamaterial structure incorporated with microstrip antenna
Authors: Rahim M. K. A. , Ibrahim N. , Majid H.A. , Murad N. A
Published: September 2012

This article presents the design, simulation, and fabrication of a new planar left‐handed metamaterial (LHM), which consist of a combination of a modified square rectangular split ring resonator and strip wire. Both structures are on the same plane. The structure is simulated and measured with the microstrip antenna operating at frequency 5.8 GHz. The LHM has been analyzed using Nicolson–Ross–Weir approach to obtain the negative permeability and permittivity at 5.8 GHz. The fabrication of the LHM is on FR‐4 board substrate. From the simulation and measurement results, the gain of the microstrip antenna with LHM has increased by 4.0 dB. The return loss of the antenna with LHM is improved to 15.7 dB compare without LHM structure. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2828–2832, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27186
Microwave frequency selective surface with controllable high Q‐factor transmission resonance
Authors: Dmitriev Victor , Kawakatsu Marcelo N.
Published: September 2012

A thin layer with a high quality factor trapped‐mode resonance and control of its resonance frequency is investigated.The structure consists of array of two metal concentric rings in a unit cell supported by a ferrite substrate. We consider magnetization normal to the array plane and two orthogonal in‐plane directions. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2762–2766, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27194
Design of graded index flat lenses with integrated antireflective properties
Authors: Good Brandon , Ransom Paul , Simmons Shaun , Good Austin , Mirotznik Mark S.
Published: September 2012

We describe a new methodology for designing graded index lenses at microwave wavelengths with integrated antireflective properties. The method leads to a flat lens with minimal reflection losses at a frequency of interest. Both numerical and experimental results for two different design goals are shown to demonstrate the capabilities of the methodology. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2774–2781, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27198
Generation of quaternary‐amplitude microwave signals by using a new optical heterodyne technique
Authors: Villena A. T. P. , Arismar Cerqueira S. , Abbade Marcelo L.F. , Hernandez‐Figueroa H. E. , Fragnito Hugo L.
Published: September 2012

We propose and experimentally investigate a new technique, based on optical heterodyne generation, which converts two optical binary amplitude‐shift keyed (2‐ASK) into a single microwave quaternary ASK (4‐ASK) one. Results show that 4‐ASK signals are properly generated even when the 2‐ASK signals are propagated through 40 km optical links from a geographically distributed optical network under real conditions of temperature, pressure, humidity, and wind. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2738–2743, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27199
Textile patch antennas using double layer fabrics for wrist‐wearable applications
Authors: Ha Sang‐jun , Jung Young‐Bae , Kim Dong ho , Jung Chang Won
Published: September 2012

This article introduces a performance investigation of textile patch antennas using double layer fabrics for wrist‐wearable applications. Two fabric substrates [top layer: conducting part (CP), bottom layer: fabric part (FP)] are used for an antenna design, and these are assembled using an adhesive. We chose polyester (PES) as the top fabric layer (CP) because the PES is a cloth of fine texture, which is useful for the steady screen printing of the antenna geometry. Four fabric samples (Fabric 1–4) were selected from actual clothes (i.e., pants and shirts), and these were used for the bottom fabric layer (FP). The textile antennas were simulated and measured to verify their performance and to compare this with that of the common microwave substrate. Moreover, a textile antenna was tested under various bent conditions as well as regarding its specific absorption rate for on‐body environments, such as the wrist and ankle. Based on the measurement results, it was confirmed that the textile antennas with double layer fabrics have good electrical performance, even in bent conditions, and can be used in wearable‐fabric applications, including body centric communications. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2697–2702, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27200
A differential BiCMOS divide‐by‐4 injection‐locked frequency divider
Authors: Chang Chia‐Wei , Jang Sheng‐Lyang
Published: September 2012

A low power wide locking range divide‐by‐4 injection‐locked frequency divider (ILFD) is proposed in the letter and was implemented in the TSMC 0.18 μm SiGe BiCMOS process. The divide‐by‐4 ILFD uses a cross‐coupled voltage‐controlled oscillator with an active inductor and a three‐transistor composite consisted of two nMOSFETs and one pMOSFET to serve as an injection device with the function of linear and nonlinear mixers. At the supply voltage of 1.5 V and at the incident power of 0 dBm, the operation range of the divide‐by‐4 is 2.3 GHz, from the incident frequency 14.5 to 16.8 GHz, the percentage is 14.7%. The locking range of the divide‐by‐4 is 1.7 GHz, from the incident frequency from 14.6 to 16.3 GHz, the percentage is 11%. The core power consumption is 1.5 mW. The die area is 0.465 × 0.317 mm2. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2825–2828, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27204
A switch controlled dual‐band band pass ΔΣ modulator
Authors: Park Bonghyuk , Jang Seunghyun , Jung Jaeho
Published: September 2012

A switch controlled fourth‐order dual‐band bandpass delta‐sigma modulator (BPDSM) is proposed. It consists of two stage second‐order resonator, high‐speed comparator, multifeedback current digital‐to‐analog converter, and clock distributer. The band selection is controlled by capacitor bank, and fine frequency tuning is done by varactor. The implemented BPDSM shows a peak signal‐to‐noise‐ratio is 41.6 dB, 42.5 dB, an error vector magnitude is 3.06%, 2.4% in 882 MHz, 955 MHz, respectively, and a differential output voltage swing is 1.32Vp‐p with dc power consumption of 389 mW. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2784–2787, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27207
1‐6 GHz 4 W MMIC GaAs high power amplifier
Authors: Pingue Massimiliano , Orobello Barbara , Diciomma Rossella , Pisa Stefano
Published: September 2012

This article presents the design of a monolithic high power amplifier with 4 W output power in the 1–6 GHz band (2.5 octave).The amplifier uses two gain stages composed by four and eight transistors. Power united monolithic semiconductor PPH25x process, on GaAs substrate with 70 μm thickness, has been used. The Montecarlo analysis shows a small‐signal gain's average value of 24 dB and output power levels higher than 36 dBm. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2747–2751, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27208
Compact and high selectivity dual‐mode dual‐band microstrip BPF with QWR and SLR
Authors: Deng Hong‐wei , Zhao Yong‐jiu , Fu Yong , Zhou Xiao‐jun , Liu Yan‐yun
Published: September 2012

In this letter, a novel compact and high selectivity dual‐mode dual‐band microstrip bandpass filter (BPF) with quarter‐wavelength resonator and stub‐loaded resonator is proposed using extended feed lines.Either of the SIRs cannot only separately generate one passband but also mainly control the passband performance. Due to the extended feed lines, parasitic coupling and intrinsic characteristics of the resonators, multiple transmission zeros can be created to improve the selectivity. Meanwhile, the BPF can obtain compact size due to the folded resonators and feed lines. A dual‐mode dual‐band BPF with the fractional bandwidth 15.6 and 6.4% is designed and fabricated. The simulated and measured results show a better agreement and validate the proposed theory. The size is only 0.185λg × 0.130λg in which λgis the guided wavelength at the first passband center frequency. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 2702:2705, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27211
Frequency of Complete Cleft Sacra in a Native American Sample
Authors: Mulhern D. M. , Wilczak C. A.
Published: September 2012

The purpose of this paper is to contribute to the current understanding of the variability of complete sacral clefts in human populations by presenting new data on a large prehistoric and historic Native American skeletal sample (n = 1943). Results are examined by age, sex, time period, and regional distribution and compared with reported frequencies of complete sacral clefts in other modern, historic, and ancient populations.

In all, 1.6% of the sample exhibited complete sacral clefts, including 2.1% of males and 1.1% of females. Although males exhibit a frequency twice as high as females, this difference is not statistically significant. However, within the Alaskan sample, the sex difference was significant (p = 0.002), with 3.4% of males and 0.5% of females exhibiting complete clefts; these differences may be related to mechanical influences during growth and development in males. Differences among age groups are not significant. Regional comparisons among Alaska, Eastern Woodlands, Great Basin/Northwest/California, Great Plains, and Southwest showed no significant differences overall, but Alaska (2.2%) and Great Plains (0.5%) do show a significant difference (p = 0.024). No significant differences were found between prehistoric, protohistoric, and historic/recent samples, suggesting a lack of a secular trend in frequency of complete sacral clefts in Native American populations. One individual exhibited an enlarged canal, which may be indicative of a more severe condition. Copyright © 2012 John Wiley & Sons, Ltd.
New advances in polysilicon processes correlating feedstock properties and good crystal and wafer performances
Authors: Ceccaroli Bruno , Lohne Otto , Øvrelid Eivind J.
Published: September 2012

Metallurgical purification routes to solar grade silicon have gained a respectable success for the manufacture of standard multicrystalline solar cells. However, gas phase chemically refined silicon (commonly designated as polysilicon) remains unchallenged for semiconductor applications and for the manufacture of monocrystalline solar cells, particularly the most popular high efficiency cell architectures. Therefore, in the medium term future virgin polysilicon should keep a predominant share of the silicon feedstock to electronic and photovoltaic wafers. For photovoltaic to meet the grid parity cost target, significant efforts have been deployed during the past years aiming at drastically reducing the cost of polysilicon. This has been achieved not only through massive capacity expansions but also through simplifying the process as well as developing new gas/solid purification and deposition processes. The replacement of the historical Siemens by the Fluidized Bed Reactor is the most accomplished example of such attempts. Worth noting is also the replacement of chlorine by other halogens in the volatile silicon bearing compound or hydrogen by metal in the deposition/reduction process. However, such cost efficient progress might have been on the expense of the ultimately desirable purity. This contribution will review the most accomplished and promising attempts to develop the polysilicon process. The potential and the limitations of the emerging polysilicon products will be illustrated with respect to their ability to produce high quality wafers for semiconductor or high efficiency solar cells (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The effect of thermal annealing on the properties of PECVD hydrogenated silicon nitride
Authors: Bousbih Rabaa , Dimassi Wissem , Haddadi Ikbel , Ezzaouia Hatem
Published: September 2012

Silicon nitride (SiNx) thin films were grown on silicon by plasma‐enhanced chemical vapor deposition (PECVD) method at low temperature by varying the silane (SiH4) to nitrogen (N2) ratio in the plasma. As‐deposited samples were investigated by varying annealing temperature from 400 °C to 950 °C in infrared (IR) heated belt furnace, in order to study their properties and correlate them to the chemical composition of the layers to find the optimized condition for application in silicon solar cells (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ginsenosides Rb1 and Rd Regulate Proliferation of Mature Keratinocytes Through Induction of p63 Expression in Hair Follicles
Authors: Li Zheng , Li Jing‐Jie , Gu Li‐Juan , Zhang Dong‐Liang , Wang Yun‐Bo , Sung Chang‐Keun
Published: September 2012

Ginsenosides Rb1 and Rd are the two main types of ginsenosides in Panax ginseng and have been used as an additive to against alopecia. However, the mechanisms involved are largely unknown. To determine how ginsenosides prevent hair loss, we topically applied protopanaxadiol‐type ginsenosides Rb1 and Rd over the shaved skin of B57CL/6 mice, and monitored and assessed them for 35 days. We then investigated the effects of ginsenosides on cell genesis in different phases of adult hair follicles (HFs), using 5‐bromo‐2′‐deoxyuridine as a marker for dividing cells. Moreover, p63, a specific marker and a major regulator of keratinocyte progenitor cells of the multi‐layered epithelia, was detected in epidermis. Results indicated that treatment with ginsenosides Rb1 and Rd increased cell proliferation in both anagen and telogen of HFs. However, it had no significant effect on the survival of cells in the bulge and upper follicle region. Investigation of p63 demonstrated that up‐regulation of p63 expression in the matrix and outer root sheath might be one of the mechanisms by which ginsenosides Rb1 and Rd promote cell proliferation in HFs. Our study reveals a novel mechanism by which ginsenoside promotes hair growth through p63 induction in follicular keratinocytes and indicates that ginsenosides Rb1 and Rd might be developed as a therapeutic agent for the prevention of hair loss. Copyright © 2012 John Wiley & Sons, Ltd.
Gingerol‐Induced Hypoxia‐Inducible Factor 1 Alpha Inhibits Human Prion Peptide‐Mediated Neurotoxicity
Authors: Jeong Jae‐Kyo , Moon Myung‐Hee , Park Yang‐Gyu , Lee Ju‐Hee , Lee You‐Jin , Seol Jae‐Won , Park Sang‐Youel
Published: September 2012

Prion diseases are a family member of neurodegenerative disorders caused by the accumulation of misfolded‐prion proteins (scrapie form of PrP, PrPSc). The accumulation of PrPSc in the brain leads to neurotoxicity by the induction of mitochondrial‐apoptotic pathways. Recent studies implicated gingerol in protection against neurodegeneration. However, the basis of the neuroprotection in prion disease remains unclear. Thus, we investigated the influence of gingerol on prion peptide‐induced neuronal damage. Gingerol blocked PrP(106‐126)‐mediated neurotoxicity by protecting mitochondrial function. Moreover, the protective effect of gingerol against PrP(106‐126)‐induced mitochondrial damage was associated with hypoxia‐inducible factor 1 alpha (HIF‐1α) expression. Gingerol‐induced HIF‐1α expression inhibited the PrP(106‐126)‐induced mitochondrial dysfunction. On the other hand, inhibition of gingerol‐induced HIF‐1 α expression attenuated the gingerol‐mediated neuroprotective effect. Here, we demonstrate for the first time that treatment with gingerol prevents prion peptide‐mediated neuronal cell death and that the neuroprotection is induced by HIF‐1α‐mediated signals. This study suggests that treatment with gingerol may provide a novel therapeutic strategy for prion‐mediated neurotoxicity. Copyright © 2012 John Wiley & Sons, Ltd.
An orbital localization criterion based on the topological analysis of the electron localization function
Authors: Oña Ofelia B. , Alcoba Diego R. , Tiznado William , Torre Alicia , Lain Luis
Published: September 2012

This work proposes a new molecular orbital localization procedure. The approach is based on the decomposition of the overlap matrix in accordance with the partitioning of the three‐dimensional physical space into basins with clear chemical meaning arising from the topological analysis of the electron localization function. The procedure is computationally inexpensive, provides a straightforward interpretation of the resulting orbitals in terms of their localization indices and basin occupancies, and preserves the σ/π‐separability in planar N‐electron systems. The localization algorithm is tested on selected molecular systems. © 2012 Wiley Periodicals, Inc.
Quantum chemistry studies of adenosine 2503 methylation by S‐adenosylmethionine‐dependent enzymes
Authors: Wang Chunling , Yang Xiaoke , Wang Endong , Li Baiqing
Published: September 2012

Ribosome methylation is important for life processes and is mainly catalyzed by radical S‐Adenosylmethionine (SAM) enzymes. Two SAM molecules serve as the cofactor by providing the 5 ′‐deoxyadenosyl radical for substrate activation and the methyl. Recently, Booker and coworkers (Science 2011, 332, 604) proposed an alternative mechanism for a pair of radical SAM enzymes, RlmN and Cfr, which respectively methylate the C2 and C8 of adenosine 2503. Their deuterium labeling experiments reveal that methyl group does not transfer directly from SAM to adenosine, instead it passes to Cys355 first, then onto adenosine. In this article, this new reaction mechanism is studied using density functional theory with B3LYP hybrid functional. The reaction system is simulated using small model compounds in the gas phase, and the protein environment is approximated using polarizable continuum model. The structures of the transition states and the intermediates are identified, and their free energies are calculated. The activation barriers indicate that the proposed reaction mechanism is plausible. The formation of a disulfide bond is found to be the rate‐limiting step. © 2012 Wiley Periodicals, Inc.
Analysis of the differentially expressed low molecular weight peptides in human serum via an N‐terminal isotope labeling technique combining nano‐liquid chromatography/matrix‐assisted laser desorption/ionization mass spectrometry
Authors: Leng Jiapeng , Zhu Dong , Wu Duojiao , Zhu Tongyu , Zhao Ningwei , Guo Yinlong
Published: September 2012

RATIONALE

Peptidomics analysis of human serum is challenging due to the low abundance of serum peptides and interference from the complex matrix. This study analyzed the differentially expressed (DE) low molecular weight peptides in human serum integrating a DMPITC‐based N‐terminal isotope labeling technique with nano‐liquid chromatography and matrix‐assisted laser desorption/ionization mass spectrometry (nano‐LC/MALDI‐MS).

METHODS

The workflow introduced a [d6]‐4,6‐dimethoxypyrimidine‐2‐isothiocyanate (DMPITC)‐labeled mixture of aliquots from test samples as the internal standard. The spiked [d0]‐DMPITC‐labeled samples were separated by nano‐LC then spotted on the MALDI target. Both quantitative and qualitative studies for serum peptides were achieved based on the isotope‐labeled peaks.

RESULTS

The DMPITC labeling technique combined with nano‐LC/MALDI‐MS not only minimized the errors in peptide quantitation, but also allowed convenient recognition of the labeled peptides due to the 6 Da mass difference. The data showed that the entire research procedure as well as the subsequent data analysis method were effective, reproducible, and sensitive for the analysis of DE serum peptides.

CONCLUSIONS

This study successfully established a research model for DE serum peptides using DMPITC‐based N‐terminal isotope labeling and nano‐LC/MALDI‐MS. Application of the DMPITC‐based N‐terminal labeling technique is expected to provide a promising tool for the investigation of peptides in vivo, especially for the analysis of DE peptides under different biological conditions. Copyright © 2012 John Wiley & Sons, Ltd.
Tandem mass spectrometric analysis and density functional theory calculations on the fragmentation behavior of two tetradecanoylingenol regioisomers from Euphorbia wallichii
Authors: Xia Bing , Xu Kaijie , Liu Xin , Chai Yunfeng , Sun Cuirong , Gu Yucheng , Ding Lisheng , Zhou Yan
Published: September 2012

RATIONALE

Two structurally similar bioactive regioisomers, 3‐O‐tetradecanoylingenol and 20‐O‐tetradecanoylingenol, from Euphorbia wallichii presented quite different fragmentation behaviors. Revealing the related fragmentation pathways may improve the efficiency of characterization and identification of such type of compounds.

METHODS

The two regioisomers were subjected to collision‐induced dissociation (CID) on Finnigan LCQDECA and LTQ Orbitrap XL instruments. Based on the CID results, the possible fragmentation pathways were proposed and investigated with density functional theory (DFT) calculations.

RESULTS

Elimination of C14H28O2 (tetradecanoic acid) for 3‐O‐tetradecanoylingenol and the sequential losses of C4H8 (butylene) for 20‐O‐tetradecanoylingenol were observed in ESI‐MS/MS, witnessed also by HR‐ESI‐MS/MS. The fragmentation pathways were proposed and verified by calculating the activation energy of their transition states by DFT calculations.

CONCLUSIONS

Based on the observations, fragmentation pathways for the two regioisomers were proposed and verified by calculating the energy of the reactants, products and the corresponding transition states using DFT. This report should have value in rapid identification of the derivatives of ingenol and other regioisomers in natural products. Copyright © 2012 John Wiley & Sons, Ltd.
Approximate controllability of stochastic nonlinear third‐order dispersion equation
Authors: Muthukumar P. , Rajivganthi C.
Published: September 2012

In this work, we consider a class of control systems governed by the stochastic nonlinear third‐order dispersion equation in Hilbert spaces. We first prove the existence of mild solutions of stochastic nonlinear third‐order dispersion equation by using fixed point theory, infinite dimensional semigroup properties, stochastic analysis techniques, and then a new set of sufficient conditions are formulated which guarantees the approximate controllability of the main problem. Finally, an example is provided to illustrate the application of the obtained results.Copyright © 2012 John Wiley & Sons, Ltd.
SPAWNING OF THE ENDANGERED AUSTRALIAN LUNGFISH (NEOCERATODUS FORSTERI) IN A HEAVILY REGULATED RIVER: A PULSE FOR LIFE
Authors: Espinoza T. , Marshall S. M. , McDougall A. J.
Published: September 2012

The Australian lungfish is an endangered native species currently protected under various state, federal and international agreements. Scarce information on their early life history is available due to the absence of juveniles collected in the wild. This has led to concerns about the sustainability of the species and become a driver for the conservation effort for Australian lungfish. This study aimed to consolidate knowledge on the critical hydraulic habitat requirements of this species within a water resource management context. In this study, spawning of Australian lungfish was found to be a seasonal strategy that is highly reliant on a variable low‐flow regime within riverine habitat. Suitable conditions for spawning were characterized by small flow events in early‐to‐mid spring when water temperatures are between 18 and 28 °C, leading to oviposition on short dense macrophytes in shallow water. Importantly, many of the key environmental factors driving the ecological response are manageable through existing water resource infrastructure. Specifically, releases from water storages within the current distribution of Australian lungfish should mimic the natural inflow and temperature regime within the spawning period, and also provide suitable riverine habitat within projected full supply limits. Copyright © 2012 John Wiley & Sons, Ltd.