bluuebunny/crossref_metadata_2025 huggingface dataset:
Simultaneous characterization of isoflavonoids and astragalosides in two Astragalus species by high‐performance liquid chromatography coupled with atmospheric pressure chemical ionization tandem mass spectrometry
Authors: Zhang Xi , Xiao Hong‐Bin , Xue Xing‐Ya , Sun Yan‐Guo , Liang Xin‐Miao
Published: July 2007

A method was developed for the simultaneous identification of astragalosides (AGs) and isoflavonoids (IFs) in the roots of Astragalus membranaceus and Astragalus mongholicus by HPLC coupled with atmospheric pressure chemical ionization MS/MS (HPLC‐APCI‐MS/MS). Diagnostic fragment ions of AGs and different group of IFs were obtained with one AG and eight IF standards analyzed by CID‐MS, which were adopted as characteristic MS/MS fingerprints for further identification of these compounds in the two Astragalus species by using HPLC‐APCI‐MS/MS. A total of 20 IFs and 10 AGs were identified or tentatively identified. Among them, six IFs were detected in A. membranaceus for the first time and five IFs were firstly identified in A. mongholicus. The results indicate that HPLC‐APCI‐MS/MS is a powerful tool for the simultaneous characterization of IFs and AGs in complex matrix.
A research agenda for the relationships between culture and knowledge management
Authors: King William R.
Published: July 2007

A preliminary research agenda for the relationship between culture, at several levels, and knowledge management (KM) practice and success is developed. The levels of culture that are considered are national culture (NC), overall organizational culture (OC), organizational climate, organizational subcultures, subunit cultures, and team climate. The national and organizational levels have previously been dealt with in largely separate research streams. The ubiquity of globalization demands that they be integrated into a single research agenda. Indicators that may serve as measures of the dependent variable in the culture–KM relationship are suggested as is a format that facilitates the formulation of specific research questions. While culture is usually thought of as the independent variable in the culture–KM dyad, the role of culture as the dependent variable in these relationships is also treated. Copyright © 2007 John Wiley & Sons, Ltd.
Multi‐band antenna applications in mobile phone
Authors: Huang Sheng‐Yi , Sun Jwo‐Shiun
Published: July 2007

This article proposes a compact novel 3‐dimension (3‐D) triple‐band antenna for mobile phone terminal equipments application. The first antenna, ANT 1, mainly contributes the regions of low frequency band. The second radiator; ANT 2, is to create the regions of high frequency band with the concept of coupling between the two antennas. The total volume of radiating element is 30 (L) × 5 (H) × 0.2 (W) mm3. The compact radiator has good characteristics of ratio of impedance bandwidth up to 33%. It is operated in three bands, 2.402–2 .4825 GHz, unlicensed NII—5 GHz UNII‐1 (5.125–5.25 GHz), and UNII‐2 (5.25–5.35 GHz) referring to the return loss −10 dB, respectively. The results of experiment are compared to numerical simulation can be agreement. The compact configuration as well as good electric characteristics of wide‐band can be achieved. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2498–2501, 2007; Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/mop.22726
Characterization of benign and malignant breast tissues using 2‐D microwave tomographic imaging
Authors: Bindu G. , Mathew K. T.
Published: July 2007

Dielectric permittivity studies and 2‐D microwave tomographic imaging are performed on benign and malignant breast tissues to characterize these tumors at the ISM band. Significant difference in the permittivity values is obtained and a distinct characterization is done based on the nature of the permittivity profiles. Also, it is observed that benign tumors exhibit sharp images with well‐defined borders, whereas malignant tumors show fuzzy and blurred boundaries. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2341–2345, 2007; Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/mop.22734
Actively mode‐locked fiber laser based on hybrid Raman and Erbium‐doped fiber gains
Authors: Chen Daru , Qin Shan
Published: July 2007

An actively mode‐locked fiber laser (AMLFL) based on the hybrid gain of a dispersion‐shifted fiber (as the Raman gain medium) and an Erbium‐doped fiber (EDF) is introduced. The fiber Raman gain mechanism can effectively suppress the gain competition of an EDF, which usually results into the supermode noise in an actively mode‐locked EDF laser. We experimentally demonstrated a stable AMLFL with the repetition of about 5 GHz, in which the supermode noise is believed to be suppressed by employing the hybrid gain medium. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2339–2341, 2007; Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/mop.22735
Pattern reconfigurable spiral antenna and its current distribution
Authors: Mehta Amit , Mirshekar‐Syahkal Dariush , Nakano Hisamatsu
Published: July 2007

Analysis of spiral antenna with open circuits on its arm is presented for beam adaptive applications. It is shown theoretically and experimentally that when the open circuits are appropriately positioned in the arm, the current distribution varies, causing the beam to steer. This effect can be exploited to design various novel beam switchable antennas. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2567–2570, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22738
Novel left‐handed transmission lines based on grounded spirals
Authors: Jokanovicé B. , Crnojevicé‐Bengin V.
Published: July 2007

Novel super‐compact (λg/13 by λg/13) left‐handed (LH) unit cell ForeS, based on grounded spirals, is analyzed in detail. ForeS exhibits low insertion losses and a large design flexibility: small changes of its inner dimensions, result in resonant frequency tuning range approximately equal to 67%. In the same time, the second harmonic is positioned at more then four times the first resonant frequency. By placing the diodes at the relevant positions, ForeS can be made electronically reconfigurable: 27% resonant frequency tuning range can be achieved, as well as different in‐ and out‐of‐band performances. Two LH transmission lines are designed using ForeS that offer a trade‐off between LH bandwidth and pass band ripple. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2561–2567, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22739
A 16‐GHz CMOS differential Colpitts VCO for DS‐UWB and 60‐GHz direct‐conversion receiver applications
Authors: Lee C.‐C. , Chuang H.‐R. , Lu C.‐L.
Published: July 2007

A 16‐GHz CMOS differential Colpitts VCO fabricated with the 0.18 μm 1P6M process is presented. The 16‐GHz VCO is a good choice for the local oscillator (LO) circuit of the UWB or 60‐GHz WPAN direct conversion receiver. The VCO is composed of a PMOS transistor‐pair core circuit and two source follower output buffers. The VCO can operate at 16.5 GHz, and the measured phase noise at 1‐MHz offset is −115 dBc/Hz. The power consumption of the VCO core is 12.6 mW. Compared with previous reported works, this VCO has an output power of −0.9 dBm and about 800‐mV output peak‐to‐peak voltage swing of the VCO core at 16.5 GHz. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2489–2492, 2007; Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/mop.22742
Effective dielectric constant and design of sliced Lüneberg lens
Authors: Zouganelis Georgios , Budimir Djuradj
Published: July 2007

In this article, a design of Lüneberg lens with slices made from low loss dielectric material with hemispherical air‐holes drilled appropriately on the top and bottom surface of each of them is presented. A formula to estimate the values of radial dependent effective dielectric constant of air‐holes dielectric composite material is suggested. The estimated values are compared with the ones calculated from finite difference time domain method electromagnetic simulations of a periodic lattice of spherical and cylindrical air‐holes embedded in a dielectric slab using Nicolson–Ross method. Calculation of S‐parameters and near field of lens with hemispherical air‐holes under an incident plane wave, using estimated effective constants by the suggested formula are compared with ones using precise theoretical values of dielectric constants. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2332–2337, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22751
Dielectric filter optimal design suitable for microwave communications by using multiobjective evolutionary algorithms
Authors: Goudos S. K. , Zaharis Z. D. , Salazar‐Lechuga M. , Lazaridis P. I. , Gallion P. B.
Published: July 2007

A multiobjective evolutionary technique is applied to design dielectric filters useful in microwave communications technology. The optimal geometry of the filters is derived by utilizing two different multiobjective optimization algorithms. The first one is the Nondominated Sorting Genetic Algorithm‐II (NSGA‐II), which is a popular multiobjective genetic algorithm. The second algorithm is based on multiobjective Particle Swarm Optimization with fitness sharing (MOPSO‐fs). MOPSO‐fs algorithm is a novel Pareto PSO algorithm that produces the Pareto front in a fast and efficient way. In the present work, MOPSO‐fs is compared with NSGA‐II to optimize the geometry of the filters under specific requirements concerning the frequency response of the filters. Several examples are studied to exhibit the efficiency of the multiobjective evolutionary optimizers and also the ability of the technique to derive optimal structures that can be used in practice. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2324–2329, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22755
Forward backward domain decomposition method for finite element solution of electromagnetic boundary value problems
Authors: Ozgun Ozlem , Kuzuoglu Mustafa
Published: July 2007

We introduce the forward–backward domain decomposition method (FB‐DDM), which is basically an improved version of the classical alternating Schwarz method with overlapping subdomains, for electromagnetic boundary value problems. The proposed method is noniterative in some cases involving smooth geometries, or it usually converges in a few iterations in other cases involving challenging geometries, via the utilization of the locally‐conformal PML method. We report some numerical results for two‐dimensional electromagnetic scattering problems. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2582–2590, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22757
ASK modulator for 900‐MHz RFID system with defected ground structure
Authors: Nae Kwan‐Kyu , Jung Jin‐Wook , Oh Ha‐Ryoung , Park Jun‐Seok
Published: July 2007

In this article, an amplitude shift keying (ASK) modulator with defected ground structure (DGS) is proposed for UHF radio frequency identification (RFID) system. Proposed variable DGS resonator with a varactor diode will be able to adjust the resonance frequency to achieve the ASK modulation. The variable resonance characteristics can be obtained by controlling capacitance of varactor diode, placed on the defected ground. To clarify corresponding method, we manufactured RFID system board using variable DGS resonator and measured the corresponding performance. As almost 93% of extracted data from modulation index characteristic is satisfied with both EPC class‐1 Gen2 Type‐B and Type‐C standard protocols, we obtained stable tag response of RFID system. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2513–2516, 2007; Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/mop.22760
Optimum dual‐resonant impedance matching of coupling element based mobile terminal antenna structures
Authors: Villanen Juha , Vainikainen Pertti
Published: July 2007

This article presents a theoretical study on optimum dual‐resonant impedance matching of coupling element based mobile terminal antenna structures. First, optimum tuning of the system of two series‐resonant circuits connected to each other with an ideal impedance transformer and an impedance inverter is studied. Simple, explicit equations are derived for optimum circuit parameters of the resonator system. After this, design rules are presented for a practical discrete‐component realization of a matching circuitry specifically optimized for nonresonant antenna structures. Special emphasis has been put on minimizing the complexity of the matching network. Discussion is also given on equivalent circuit modeling of the combination of chassis and a coupling element. The presented matching network design methodology is shown to work well when applied with a realistic coupling element based mobile terminal antenna structure. The results of this article also indicate that the combination of the chassis of a mobile terminal and a simple coupling element can be with a good enough accuracy approximated as a series‐RLC equivalent circuit. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2472–2477, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22762
An accurate scaling approach for small‐signal modeling of high‐power HBT devices
Authors: Bousnina Sami
Published: July 2007

This paper presents an accurate scaling approach for small‐signal modeling of high‐power multi‐cell heterojunction bipolar transistors (HBTs). This approach is mainly based on the characterization of an elementary‐cell device and a proper modeling of the metalwork structure surrounding the transistor intrinsic part. The determined elementary‐cell small‐signal model is then scaled up to generate the S‐parameters of the multi‐cell device. An experimental validation was performed on a single‐cell and three‐cells GaAsHBT devices and excellent agreement was obtained between measured and simulated S‐parameters over frequency range 1–15 GHz. This modeling approach is particularly useful for on‐wafer characterization and modeling of high power HBT devices. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2429–2434, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22765
A novel expression for effective radius in calculating the resonant frequency of circular microstrip patch antennas
Authors: Akdagli Ali
Published: July 2007

This letter presents a novel effective radius expression for determining the resonant frequency of circular microstrip patch antennas. The effective patch radius expression is constructed by using differential evolution algorithm and is valid for both electrically thin and thick circular microstrip antennas (MSAs). It is well suited to be used in the development of fast computer aided design algorithms. Numerical results obtained for the resonant frequencies of circular MSAs are in good agreement with the experimental results reported by several scientists. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2395–2398, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22767
A CPW‐fed staircase monopole UWB antenna with band‐notched frequency in the WLAN band
Authors: Kim Sang Joong , Lee Hyoung Sik , Kim Young‐Sik
Published: July 2007

A coplanar waveguide (CPW)‐fed ultra‐wideband staircase monopole antenna with a frequency‐notch characteristic is presented. The proposed antenna consists of a planar four‐step staircase rectangular monopole with a ground short‐circuited stub, open stubs at the ground part, and two‐step impedance transformer at the CPW‐fed line. The impedance bandwidth is increased due to an offset feeding technique and one‐side ground notch. The notched frequency band can be accomplished by means of the method that involves adding open stubs at the ground. The measured results are in good agreement with the simulated ones. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2545–2547, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22775
The design of printed rhomb‐shaped antenna with slits for WiMAX systems
Authors: Chen Wen‐Shan , Yu Yen‐Hao
Published: July 2007

The article proposed and studied a coplanar waveguide CPW‐feed antenna. In this design, broadband structure covers from 2.43 to 7.2 GHz, which has impedance bandwidth above of 100%. The resonant frequency was obtained by adjusting the length of notch and the distance between radiation patch and ground plane. Furthermore, embedded the symmetrical slits close to a quarter wavelength on the rhomb patch and ground plane, respectively. It plays a role as a filter to eliminate the useless band. The proposed antenna with band‐rejection characteristic is calibrated for WiMAX (worldwide interoperability for microwave access, IEEE 802.16a/d/e/2004) applications which cover the band from 2.495 to 2.69 GHz, 3.3 to 3.8 GHz, and 5.25 to 5.85 GHz. And, this antenna has advantages of good radiation characteristic, compact size, and omni‐directional patterns. Details of the proposed antenna configuration and the experimental results are discussed. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2503–2508, 2007; Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/mop.22777
Multilayer frequency selective surface with grating lobe suppression
Authors: Luo Guo Qing , Hong Wei , Lai Qing Hua , Sun Ling Ling
Published: July 2007

Conventional multilayer frequency selective surface combined with substrate‐integrated waveguide technique for grating lobe suppression is studied in this letter. Simulation and experiment results show that the grating lobe generated by middle dielectric layer can be greatly suppressed using this structure. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2501–2503, 2007; Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/mop.22778
A high‐performance 1–7 GHz UWB LNA using standard 0.18 μM CMOS technology
Authors: Yen Shu‐Hui , Chen Chang‐Zhi , Lin Yo‐Sheng , Chen Chi‐Chen
Published: July 2007

In this article, we demonstrate a high‐performance 1‐ to 7‐GHz ultra‐wideband (UWB) low‐noise amplifier (LNA) for UWB system applications implemented in a standard 0.18 μm CMOS technology. This LNA can also be applied to 1.8/1.9‐GHz‐band GSM systems, and 2.4/4.9/5.2/5.7‐GHz‐band WLAN systems. The LNA consists of two cascaded stages, in which the pole of the first stage is cancelled by the zero of the second stage over the 1–7 GHz of interest. In addition, the inductive peaking technique is adopted in the second stage for bandwidth enhancement. This LNA achieved input return loss (S11) of −10 to −15.3 dB, output return loss (S22) of −19.4 to −10.3 dB, voltage gain (AV) of 13.3 to 14.6 dB, reverse isolation (S12) of −37.7 to −27.1 dB over the 1‐ to 7‐GHz band of interest. The measured noise figure (NF) was 4.86–4.35 dB over the 2–8.5 GHz band. The measured 1‐dB compression point (P1dB) and third‐order inter‐modulation point (IIP3) were −13.5 dBm and −3 dBm, respectively, at 6 GHz. The chip area was only 500 μm × 582 μm excluding the test pads. This LNA drained 10.4 mA current at supply voltage of 1.5 V, i.e. it only consumed 15.6 mW power. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2458–2462, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22780
A fast physical optics method for planar scatters with arbitrary contour
Authors: Bondía Felipe Vico , Bataller Miguel Ferrando , Valero‐Nogueira Alejandro , Alos Esperanza Alfonso
Published: July 2007

A new 3D fast physical optics method is presented for computing the diffracted field by a conducting plate with arbitrary contour. This is a fast and accurate method both in low and high frequency. This method combines classical path deformation technique with Jacobi orthogonal polynomial approximation. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2613–2618, 2007; Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/mop.22787
An architecture for active metamaterial particles and experimental validation at RF
Authors: Popa Bogdan‐Ioan , Cummer Steven A.
Published: July 2007

We describe a class of metamaterial particle that employs active elements to overcome the inherent limitations of their passive counterparts, such as significant losses, high dispersion, and narrow bandwidth. The active unit cell can be designed to have either an electric or magnetic response. For a magnetic active metamaterial, we derive the design equations for the unit cell and validate them experimentally through the extraction of effective permittivity and permeability from S‐parameter measurements of a unit cell in a waveguide. We show that phase delay in the amplifier can be used to control losses and dispersion. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2574–2577, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22789
Analysis of time‐dependent cylindrical problems using Monte Carlo
Authors: Sadiku M. N. O. , Akujuobi C. M. , Musa S. M. , Nelatury Sudarshan R.
Published: July 2007

Monte Carlo method is well known for solving static problems such as Laplace's or Poisson's equation. In this article, we extend the applicability of the conventional Monte Carlo method to solve time‐dependent cylindrical problems. We present results in one‐dimensional and two‐dimensional regions that agree with the exact solutions. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2571–2573, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22790
A graphical tool for analysis and design of bi‐characteristic‐impedance transmission lines
Authors: Torrungrueng D. , Chou P. Y. , Krairiksh M.
Published: July 2007

The bi‐characteristic‐impedance transmission lines (BCITLs) are generally lossy transmission lines that possess different complex characteristic impedances for waves propagating in forward and reverse directions. Because of complicated equations associated with BCITLs, a graphical tool is necessary in the analysis and design. In this article, the standard T‐chart developed for conjugately characteristic‐impedance transmission lines (CCITLs) is generalized to treat BCITL problems, called a generalized T‐chart. It is found that the way of using this new graphical tool is similar to that of the standard T‐chart. However, the magnitude of the voltage reflection coefficient associated with BCITLs may be greater than unity for some passive load terminations. An example of using a generalized T‐chart is provided in this paper. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2368–2372, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22801
Altered expression ofPGK1in a family with phosphoglycerate kinase deficiency
Authors: Svaasand Eva K. , Aasly Jan , Landsem Veslemøy Malm , Klungland Helge
Published: July 2007

The X‐linked recessive disease phosphoglycerate kinase (PGK) deficiency is caused by altered expression of the PGK1 enzyme, which causes muscle stiffness, hemolytic anemia, and mental retardation. In this study we characterized thePGK1gene in a family of two brothers, two sisters, and their parents. A single mutation in exon 6, which was associated with the pattern of inheritance of PGK1 deficiency, was observed. This silentG213G;c.639C>Tmutation was localized to the conserved exon–intron boundary. We have developed a method for quantification of PGK1 mRNA and demonstrated a marked reduction in PGK1 mRNA in both brothers with the disease. A smaller decrease in PGK1 expression was observed in one sister with symptoms of PGK deficiency and in her mother. Only the normal PGK1 allele was expressed in the two heterozygous women. Whereas most known PGK1 mutations cause amino acid alterations, our study indicates that inhibition of the transcription mechanism is the cause of PGK deficiency. Muscle Nerve, 2007
Isotonic fatigue in laminin α2–deficient dy/dy dystrophic mouse diaphragm
Authors: Pollarine Jennifer , Moyer Michelle , Van Lunteren Erik
Published: July 2007

Laminin α2 deficiency causes ∼50% of human congenital muscular dystrophies. Muscle in the corresponding dy/dy mouse model has reduced force but increased fatigue resistance during isometric contractions. To determine whether a similar pattern of alterations is present during isotonic contractions, dy/dy diaphragm was studied in vitro. During 20% load, dystrophic diaphragm had significantly reduced shortening, shortening velocity, work and power deficits, which persisted during the fatigue‐inducing stimulation. In contrast, during 40% load, isotonic contractile performance of diseased muscle was impaired only mildly and only for some contractile parameters. At both loads, rate of isotonic fatigue when expressed relative to initial contractile values was similar for dystrophic and normal muscle, or in some instances slightly higher for dystrophic muscle. Therefore, fatigue resistance is considerably impaired during isotonic contractions relative to that reported previously for isometric contractions. This has important implications for increased susceptibility to respiratory failure in laminin α2–deficient muscular dystrophy. Muscle Nerve, 2007
Palaeocytology in skeletal remains: microscopic examination of putrefaction fluid deposits and dental calculus of skeletal remains from French archaeological sites
Authors: Blondiaux J. , Charlier P.
Published: July 2007

The relatively elusive nature of preserved human cells in fossilised tissues was recognised prior to the description of fossilised sickle cells by Maat (1991) and Maat & Baig (1991). Preserved neural cells were also noted in mummified brain tissues by Hauswirth et al. (1991) and Doran et al. (1986). Exceptional circumstances of preservation were used to explain these rare observations (Briggs & Kear, 1993). In this study, dental calculus and endocranial putrefaction fluid were rehydrated for 12 hours in 0.4 M acetic acid solution at room temperature, smear stained with May‐Grunwald‐Giemsa and examined using light microscopy. Remnants of leucocytes, epithelial cells and other cells are presented and discussed. Copyright © 2007 John Wiley & Sons, Ltd.
Ultra‐high long‐term stability of oxide‐TTFTs under current stress
Authors: Riedl T. , Görrn P. , Hölzer P. , Kowalsky W.
Published: July 2007

In this letter the stability of transparent thin‐film transistors (TTFTs) based on the ZnO–SnO2 (ZTO) material system is investigated. Bottom‐gate devices have been subject to electrical stress via a gate–source bias of 10 V and a drain‐source bias of 10 V leading to a drain–source current of 188 µA. In optimized TTFTs with a composition of [Zn]:[Sn] = 36:64 the relative change of the saturated field effect mobility was less than 1% and the threshold voltage shift was about 320 mV after 1000 hours of operation. This extraordinary stability of ZTO TTFTs underlines their suitability as drivers in active matrix OLED displays. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Aloe‐emodin suppressed NMDA‐induced apoptosis of retinal ganglion cells through regulation of ERK phosphorylation
Authors: Lin Hui‐Ju , Chao Pei‐Dawn Lee , Huang Shiuan‐Yi , Wan Lai , Wu Chen‐Ju , Tsai Fuu‐Jen
Published: July 2007

A high concentration of glutamate in the vitreous body and optic nerves of the eyes activatesN‐methyl‐d‐aspartate (NMDA) receptors and is toxic to retina ganglion cells (RGCs) in glaucomatous patients. Aloe‐emodin sulfates/glucuronides (s/g), the major metabolites of aloe‐emodin, was found to be effective in decreasing NMDA‐induced apoptosis in RGCs. In order to elucidate the mechanisms, anin vitrooptic neuropathy model adding NMDA to N18 RGCs was used in this study. The phosphorylation level of extra‐cellular signal‐regulated kinase1/2 (ERK1/2), c‐JunN‐terminal kinase (JNK) and p38 kinase (cytokines‐suppressive antiinflammatory drug binding protein kinase) were measured by western blotting and luciferase reporter assay. The results showed that aloe‐emodin metabolites significantly decreased the activation of three major mitogen‐activated protein (MAP) kinase pathways and the activation of downstream genes in nucleus induced by NMDA, which were verified by the addition of the respective inhibitors. Comparing the effect of the inhibitors of the three MAP kinase pathways, the ERK pathway was found to be the major route of aloe‐emodin metabolites in decreasing the apoptosis of NMDA‐treated RGCs. Besides, cfos rather then cjun was the target downstream gene. Aloe‐emodin emodin metabolites could regulate the phosphorylation of ERK kinases and it was a promising candidate for NMDA‐induced apoptosis of RGCs. Copyright © 2007 John Wiley & Sons, Ltd.
The effect of Echinacea purpurea, Astragalus membranaceus and Glycyrrhiza glabra on CD25 expression in humans: a pilot study
Authors: Zwickey Heather , Brush Julie , Iacullo Carolyn M. , Connelly Erin , Gregory William L. , Soumyanath Amala , Buresh Randal
Published: July 2007

This phase 0, double‐blind, repeated within subject, randomized pilot study examined CD25 expression on T cells after ingestion of three commonly used herbs: Echinacea purpurea, Astragalus membranaceus and Glycyrrhiza glabra, administered singly and in combination. CD25 expression on T cells was significantly increased for subjects ingesting Echinacea at 24 h with notable increases in activation from Astragalus and Glycyrrhiza. CD25 expression remains elevated with daily use of Echinacea for at least 7 days. Copyright © 2007 John Wiley & Sons, Ltd.
Antiproliferative activity of Hungarian Asteraceae species against human cancer cell lines. Part I
Authors: Réthy Borbála , Csupor‐Löffler Boglárka , Zupkó István , Hajdú Zsuzsanna , Máthé Imre , Hohmann Judit , Rédei Tamás , Falkay George
Published: July 2007

Aqueous and organic extracts of 25 selected species from four tribes of Hungarian Asteraceae were screened in vitro for antiproliferative activity against HeLa (cervix epithelial adenocarcinoma), A431 (skin epidermoid carcinoma) and MCF7 (breast epithelial adenocarcinoma) cells, using the MTT assay. Twenty five of the 228 tested extracts from different parts of the species of Astereae (6), Inuleae (3), Heliantheae (5) and Anthemideae (11) demonstrated a substantial antiproliferative effect (at least 50% inhibition of cell proliferation) at 10 µg/mL against one or more of the cell lines. Complete dose‐response curves were generated and IC50 values were calculated for these active extracts, and their direct cytotoxic effects were determined. In summary, 11 of the tested 25 plants were found to be active and 4 of them (Anthemis ruthenica, Erigeron canadensis, Erigeron annuus and Inula ensifolia) had not been studied previously for either active compounds or anticancer properties. Copyright © 2007 John Wiley & Sons, Ltd.
Protective effects of American ginseng (Panax quinquefolium) against mitomycin C induced micronuclei in mice
Authors: Pawar Amol Ashok , Tripathi Durga Nand , Ramarao Poduri , Jena Gopabandhu
Published: July 2007

Mitomycin C (MMC) is a highly active anticancer drug commonly used alone and in combination with other chemotherapeutic agents for the treatment of different cancers. Its bioactivated form critically damages the DNA present in both rapidly dividing cancerous cells as well as in normal cells. Genotoxicity in the normal cells makes this drug highly toxic; thereby decreasing its therapeutic index for clinical use. The study investigated the chemoprotective potential of American ginseng root extract against MMC by using the micronuclei test in a mouse test system. Pre‐treatment with ginseng at doses 50 mg/kg and 100 mg/kg, p.o. for 3 and 7 days significantly decreased the frequency of micronucleated polychromatic erythrocytes (PCEs). Similar protective effects were also observed during co‐treatment with ginseng at similar doses for 3 and 7 days. The present results indicate that American ginseng extract is capable of suppressing the chromosomal aberration induced by MMC in mice. Thus, American ginseng may be a potent chemoprotective agent against the toxicity of the anticancer drug, mitomycin C. Copyright © 2007 John Wiley & Sons, Ltd.
A novel extracellular protease with fibrinolytic activity from the culture supernatant of Cordyceps sinensis: purification and characterization
Authors: Li Hua‐ping , Hu Zheng , Yuan Jiang‐lan , Fan Han‐dong , Chen Wei , Wang Shi‐jia , Zheng Shan‐shan , Zheng Zhong‐liang , Zou Guo‐lin
Published: July 2007

A novel serine protease with fibrinolytic activity named CSP was purified from the culture supernatant of the fungus Cordyceps sinensis, a kind of Chinese herbal medicine. Analysis of the purified enzyme by SDS‐PAGE indicated that CSP was a single polypeptide chain with an apparent molecular weight of 31 kDa, and N‐terminal sequencing revealed that the first ten amino acid residues of the enzyme were Ala‐Leu‐Ala‐Thr‐Gln‐His‐Gly‐Ala‐Pro‐Trp‐. When casein was used as a substrate, the proteolytic activity of CSP reached its maximum at pH 7.0 and 40 °C. The effect of chemical agents on the enzyme activity indicated that CSP is a serine protease with a free cysteine residue near the active site. It hydrolysed fibrinogen, fibrin and casein with a high efficiency, while hydrolysing bovine serum albumin (BSA) and human serum albumin (HSA) to a lesser extent. CSP was found to be a plasmin‐like protease, but not a plasminogen activator, and it preferentially cleaved the Aα chain of fibrinogen and the α‐chain of fibrin. Therefore, the extracellular protein CSP may represent a potential new therapeutic agent for the treatment of thrombosis. Copyright © 2007 John Wiley & Sons, Ltd.
Presence of endogenous interferences in the urinary detection of selected anabolic steroids by liquid chromatography/electrospray tandem mass spectrometry
Authors: Pozo Oscar J. , Deventer Koen , Van Eenoo Peter , Delbeke Frans T.
Published: July 2007

The use of liquid chromatography/tandem mass spectrometry (LC/MS/MS) can give several benefits in the urinary detection of anabolic steroids (AS) such as avoiding the derivatization step or the possible direct detection of conjugated AS. However, the presence of endogenous compounds with similar structures can interfere with this detection, thus decreasing the reliability of the method. The circumvention of these interferences by the use of different MS/MS transitions has been studied. For 17α‐trenbolone, an unusual odd‐electron ion has been selected for detection. Using this approach, the interferences have been reduced drastically. The selection of a more specific precursor ion can also help in the circumvention of interferences. This has been shown for 1‐testosterone, 5β‐androst‐1‐ene‐17β‐ol‐3‐one and oxandrolone where the selection of the uncommon [M+H+MeOH]+ as the precursor ion increased the selectivity of the method. In addition, an approach to identify the endogenous interferences if they have corticosteroid or steroid structure has been evaluated. Precursor ion spectra can be used to define the molecular properties of the interferences and to predict whether it is an endogenous steroid or corticosteroid. The use of some restrictions for the structure can be helpful in outlining a feasible hypothesis. This data and the product ions from likely suspects can be used to identify AS. Using this approach, several endogenous interferences have been elucidated in this case study. The knowledge about the structures of these interferences has been found useful to circumvent their detection in the screening method for AS. Copyright © 2007 John Wiley & Sons, Ltd.
Characterization of metabolites of a NK1 receptor antagonist, CJ‐11,972, in human liver microsomes and recombinant human CYP isoforms by liquid chromatography/tandem mass spectrometry
Authors: Prakash Chandra , Lin Jinyan , Colizza Kevin , Miao Zhuang
Published: July 2007

The in vitro metabolism of CJ‐11,972, (2‐benzhydryl‐1‐aza‐bicyclo[2.2.2]oct‐3‐yl)‐(5‐tert‐butyl‐2‐methoxybenzyl)amine, an NK1 receptor antagonist, was studied in human liver microsomes and recombinant human CYP isoforms. Liquid chromatography/mass spectrometry (LC/MS) and tandem mass spectrometry (LC/MS/MS) coupled to radioactive detection were used to detect and identify the metabolites. CJ‐11,972 was extensively metabolized in human liver microsomes and recombinant human CYP 3A4/3A5 isoforms. A total of fourteen metabolites were identified by a combination of various MS techniques. The major metabolic pathways were due to oxidation of the tert‐butyl moiety to form an alcohol (M6) and/or O‐demethylation of the anisole moiety. The alcohol metabolite M6 was further oxidized to the corresponding aldehyde (M7) and carboxylic acid (M4). Two unusual metabolites (M13, M17), formed by C‐demethylation of the tert‐butyl group, were identified as 2‐{3‐[(2‐benzhydryl‐1‐aza‐bicyclo[2.2.2]oct‐3‐ylamino)methyl]‐4‐methoxyphenyl}propan‐2‐ol and (2‐benzhydryl‐1‐aza‐bicyclo[2.2.2]oct‐3‐yl)‐(5‐isopropenyl‐2‐methoxybenzyl)amine. A plausible mechanism for C‐demethylation may involve oxidation of M6 to form an aldehyde metabolite (M7), followed by cytochrome P450‐mediated deformylation leaving an unstable carbon‐centered radical, which would quickly form either the alcohol metabolite M13 and the olefin metabolite M17. Copyright © 2007 John Wiley & Sons, Ltd.
Instream restoration: its effects on lateral stream–subsurface water exchange in urban and agricultural streams in Southern Ontario
Authors: Kasahara Tamao , Hill Alan R.
Published: July 2007

Instream restoration strategies do not generally consider the subsurface environment. The study of recently restored stream reaches can provide an opportunity to assess the impacts of restoration on surface–subsurface exchange. In this study, lateral hyporheic zones occurring in a constructed gravel bar and re‐meandered stream reach were examined, using hydrometric data in combination with differences in background conservative ion and tracer injection experiments. Both the constructed gravel bar and the meander bends induced lateral hyporheic exchange flow. In the gravel bar, lateral hyporheic exchange increased after a riffle‐pool sequence was constructed in the channel adjacent to the bar. The substrate in the meander bends had low saturated hydraulic conductivity, and the stream–subsurface exchange was limited despite the large change in channel configuration. These results suggest that to enhance and maintain stream–subsurface water exchanges, restoration projects that modify horizontal geometry should involve construction of vertical morphologic features, and where floodplain sediments are fine‐grained, the addition of coarse sediments should also be incorporated in the design. Copyright © 2007 John Wiley & Sons, Ltd.
Seasonal variation in nutrient retention during inundation of a short‐hydroperiod floodplain
Authors: Noe Gregory B. , Hupp Cliff R.
Published: July 2007

Floodplains are generally considered to be important locations for nutrient retention or inorganic‐to‐organic nutrient conversions in riverine ecosystems. However, little is known about nutrient processing in short‐hydroperiod floodplains or seasonal variation in floodplain nutrient retention. Therefore, we quantified the net uptake, release or transformation of nitrogen (N), phosphorus (P) and suspended sediment species during brief periods (1–2 days) of overbank flooding through a 250‐m floodplain flowpath on the fourth‐order Mattawoman Creek, Maryland U.S.A. Sampling occurred during a winter, two spring and a summer flood in this largely forested watershed with low nutrient and sediment loading. Concentrations of NO increased significantly in surface water flowing over the floodplain in three of the four floods, suggesting the floodplain was a source of NO. The upper portion of the floodplain flowpath consistently exported NH, most likely due to the hyporheic flushing of floodplain soil NH, which was then likely nitrified to NO in floodwaters. The floodplain was a sink for particulate organic P (POP) during two floods and particulate organic N and inorganic suspended sediment (ISS) during one flood. Large releases of all dissolved inorganic N and P species occurred following a snowmelt and subsequent cold winter flood. Although there was little consistency in most patterns of nutrient processing among the different floods, this floodplain, characterized by brief inundation, low residence time and low nutrient loading, behaved oppositely from the conceptual model for most floodplains in that it generally exported inorganic nutrients and imported organic nutrients. Published in 2007 by John Wiley & Sons, Ltd.
Multi‐scale modelling of land‐use change and river training effects on floods in the Rhine basin
Authors: Bronstert A. , Bárdossy A. , Bismuth C. , Buiteveld H. , Disse M. , Engel H. , Fritsch U. , Hundecha Y. , Lammersen R. , Niehoff D. , Ritter N.
Published: July 2007

Land‐use changes effects on floods are investigated by a multi‐scale modelling study, where runoff generation in catchments of different sizes, different land uses and morphological characteristics are simulated in a nested manner. The macro‐scale covers the Rhine basin (excluding the alpine part), the upper meso‐scale covers various tributaries of the Rhine and three lower meso‐scale study areas (100–500 km2) represent different characteristic land‐use patterns. The main innovation is the combination of models at different scales and at different levels of process representation in order to account for the complexity of land‐use change impacts for a large river basin.

The results showed that the influence of land‐use on storm runoff generation is stronger for convective storm events with high precipitation intensities than for long advective storms with low intensities. The simulated flood increase at the lower meso‐scale for a scenario of rather strong urbanization is in the order of 0 and 4% for advective rainfall events, and 10–30% for convective rain storms with a return period of 2–10 years.

Convective storm events, however, are of hardly any relevance for the formation of floods in the large river basins of Central Europe, because the extent of convective rainstorms is restricted to local occurrence. Due to the dominance of advective precipitation for macro‐scale flooding, limited water retention capacity of antecedent wet soils and superposition of flood waves from different tributaries, the land‐use change effects at the macro‐scale are even smaller, for example at Cologne (catchment area 100 000 km2), land‐use change effects may result in not more than 1–5 cm water level of the Rhine. Water retention measures in polders along the Upper and Lower Rhine yield flood peak attenuation along the Rhine all the way down to the Dutch border between 1 and 15 cm. Copyright © 2007 John Wiley & Sons, Ltd.
Analysis of the SSI from an instrumented building response
Authors: Zaicenco A. , Alkaz V.
Published: July 2007

The long‐term project for seismic instrumentation of a 16‐storey reinforced concrete cast‐in‐place dwelling building (str. Roz 15, Chisinau, Republic of Moldova) has provided data on structural response during moderate‐magnitude (Gutenberg‐Richter MGR = 5·0–6·7) earthquakes since the late 1970s. The effect of soil–structure interaction (SSI) is clearly observed from the recorded response. SSI becomes more pronounced for higher level of ground shaking (larger magnitudes), amplifying and increasing the predominant period of the structure and slightly suppressing high frequencies on the foundation in comparison with the free‐field motion. Numerical examples which highlight the problem issues and support the conclusions are presented using finite element method and bidirectional lumped‐mass storey‐stiffness models. Copyright © 2007 John Wiley & Sons, Ltd.
Progressive collapse analysis of an RC structure
Authors: Sasani Mehrdad , Kropelnicki Jesse
Published: July 2007

Progressive collapse denotes a failure of a major portion of a structure that has been initiated by failure in a relatively small portion of the structure. One approach to evaluate progressive collapse of structures is to study the effects of instantaneous removal of a load‐bearing element such as a column. An experimental program is carried out to study the behavior of a 3/8 scaled model of a continuous perimeter beam in a reinforced concrete frame structure following the removal of a supporting column. A detailed finite element model (FEM) is developed and verified to capture the behavior of the beam subjected to large deformation. In order to avoid a detailed FEM of the whole building and to efficiently capture the system response, a three‐dimensional nonlinear model of the structure using beam–column and shell elements is also developed. The two models are integrated through hybrid (substructuring) simulations. The potential progressive collapse of the structure and the dynamic load redistributions following column removals are studied. Copyright © 2007 John Wiley & Sons, Ltd.
Measurement of lipid oxidation: A review
Authors: Gray J. I.
Published: July 2007

Lipids become rancid as a result of oxidation, and this oxidative rancidity is a major cause of food deterioration. The acceptability of a food product depends on the extent to which this deterioration has occurred. Thus some criterion for assessing the extent of oxidation is required. This paper reviews the experimental techniques for the measurement of lipid oxidation. The spectrum of tests ranges from simple organoleptic evaluations to chemical and physical methods. There is no ideal chemical method which correlates well with changes in organoleptic properties of oxidized lipids throughout the entire course of autoxidation. The methods discussed each give information about particular stages of the autoxidative process, and some are more applicable to certain lipid systems than others. The method of choice depends on a number of factors including the nature and history of the oxidized sample, the type of information required, the time available, and the test conditions. Clearly, there is a need for a more thorough assessment of the available methods so that unreliable, cumbersome methods may be discarded and modifications made to the remaining methods to maximize the information obtained. The ultimate criterion for the suitability of any test is its agreement with sensory perception of rancid flavors and odors.
Effects of ph on foam stability of dimethyldodecylamine oxide and n‐dodecyl‐2‐anninopropionic acid in aqueous solutions
Authors: Tsujii K. , Arai H.
Published: July 2007

Foam stability of aqueous solutions of dimethyl‐dodecylamine oxide (DMAO) and N‐dodecyl‐2‐aminopropionic acid (DAPA) has been studied in relation to pH by means of the dynamic method. The foam of DMAO solution is stabilized in the acidic pH region, while with the DAPA solution, the foam is stable in either the acidic or basic pH range and unstable between them. The results suggest that the foam stability of the solutions of these two surfactants is governed by the formation of ionic species of the surfactants. It can be presumed that the adsorption of the ionic species of the surfactant molecules at the surface of foam films establishes an electric double‐layer which makes the foams stable.