bluuebunny/crossref_metadata_2025 huggingface dataset:
Eccentric core single‐mode fiber optical attenuator
Authors: Fan Linyong , Jiang Weiwei , Zhao Ruifeng , Pei Li , Jian Shuisheng
Published: March 2011

An all‐fiber optical attenuator is fabricated by splicing an eccentric core single‐mode fiber (ECSMF) between two single‐mode fibers (SMFs).The attenuation is mainly caused by the core offset between the ECSMF and the SMFs. Attenuators with different attenuations were fabricated. The device is simple, reliable, economical, and temperature independent. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1236–1238, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26003
Comparison of precorrected FFT/adaptive integral method matching schemes
Authors: Yang Kai , Yilmaz Ali E.
Published: March 2011

This article presents a detailed comparison of the moment, near‐field, and far‐field matching schemes that are used in precorrected FFT/adaptive integral method solvers to anterpolate currents (interpolate fields) on the nonuniform mesh of a structure of interest in terms of sources (observers) on an auxiliary regular grid. A general error measure is developed to evaluate the matching schemes in free space or layered media and for the high‐ or low‐frequency regime of operation. It is shown that moment matching is the most robust scheme, that far‐field matching is the most accurate scheme for high‐frequency regime but breaks down for low‐frequency regime, and that near‐field matching is more accurate than moment matching but requires the most preprocessing operations. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1368–1372, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26006
Modeling of compact microstrip resonator using neural network: Application to design of compact low‐pass filter with sharp cut‐off frequency
Authors: Hayati Mohsen , Lotfi Ali
Published: March 2011

In this article, S‐parameters of compact microstrip resonator cell are predicted using artificial neural network (ANN) to design class of elliptic function compact low‐pass filter with sharp cut‐off frequency. The ANN structure used in this work is multilayer perceptron (MLP) neural network. The data used for training the network is obtained using electromagnetic (EM) simulator. We compared measurement results and simulation results of filter by EM‐simulator and ANN. The results show accurate attenuation at cut off frequency. In comparison with EM‐simulator, simulation results by ANN have merits such as: mitigated consumption time, efficient performance and good accuracy. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1323–1328, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26008
High‐Q frequency shifting recirculating delay line bandpass photonic filter
Authors: Pulikkaseril C. , Chan E. H. W. , Minasian R.A.
Published: March 2011

An all‐optical photonic bandpass filter which achieves a very high‐Q performance while simultaneously exhibiting low noise operation, is presented. It can generate a large number of taps without the problem of lasing thus enabling the realisation of high‐resolution bandpass filtering. Experimental results for a photonic filter demonstrate a Q factor of 407, together with low noise and a stopband rejection of 50 dB. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1284–1286, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26011
Single probe‐fed circularly polarized patch antennas with U‐slots
Authors: Fong Lee Kai , Man Luk Kwai , Chi Mok Wing , Nayeri Payam
Published: March 2011

Detailed studies were presented for two recent designs of single probe‐fed circularly polarized patch antennas with U‐slots. In one design, a square patch with truncated corners is used to generate circular polarization, while a symmetric U‐slot is etched on the patch to increase the usable bandwidth of the antenna. In the second design, both these functions are accomplished by means of an asymmetric U‐slot in a square patch. Previously published studies were on air substrate only. One of the purposes of this article is to extend the study of the two designs for material substrates. The second purpose is to compare the performances of the two designs. It was found that, for the same substrate thickness, both the bandwidth and the gain of the symmetric design are somewhat better than the asymmetric design. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1245–1253, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26012
Doubly miniaturized rat‐race hybrid coupler
Authors: Kurgan P. , Kitlinski M.
Published: March 2011

Two complementary miniaturization techniques have been applied to reduce the size of a rat‐race hybrid coupler: (i) conventional microstrip sections have been replaced with their diminished low‐impedance counterparts as the first step of size reduction and (ii) novel fractal‐shaped compact microstrip resonant cells dedicated to efficiently shorten low‐impedance transmission line segments have been implemented as the second step of circuit miniaturization.The experimental results are in excellent agreement with theoretical characteristics. Moreover, the application of the proposed complementary miniaturization methods enabled the achievement of ∼73% scale of size reduction, which illustrates the attractive possibilities of the approach. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1242–1244, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26013
Channel capacity study of polarization reconfigurable slot antenna for indoor MIMO system
Authors: Li Yue , Zhang Zhijun , Zheng Jianfeng , Feng Zhenghe
Published: March 2011

This article presents a polarization reconfigurable slot antenna with compact feed.Fed by dual modes of coplanar waveguide, a dual orthogonal linear polarization is excited in the slot and controlled by two PIN diodes. The proposed antenna has been built and its reflection coefficient, radiation pattern, gain were tested. The capacity performance in an indoor wireless local area network scenario was measured by using two proposed antennas as access point in a 2 × 2 multi‐input multi‐output system. The results show the advantage of polarization reconfigurable antennas in channel capacity, especially at the condition of non‐line‐of‐sight. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1209–1213, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26014
Electromagnetic modeling of massively coupled through silicon vias for 3D interconnects
Authors: Wu Boping , Gu Xiaoxiong , Tsang Leung , Ritter Mark B.
Published: March 2011

This article presents a full‐wave electromagnetic approach for analyzing the electrical performance of massively coupled through silicon vias (TSV). The TSVs are modeled with SiO2 insulation coating and are placed in the sandwiched SiO2‐Si‐SiO2 substrate. The planar guided wave is analyzed to determine the fundamental mode and high order modes in stratified media. Cylindrical wave expansions and Foldy–Lax equations for multiple scattering techniques are adapted to the TSV problems. The effect of SiO2 coating around the via is modeled by the general expression of T‐matrix coefficients. Both dispersive silicon loss and copper loss are included in this approach. Numerical simulation of a 4‐by‐4 TSV array is demonstrated to show the signal performance and crosstalk. It shows that the coupling issues among the TSVs will become significant beyond 15 GHz. The results are in excellent agreement with general purpose field solver. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1204–1206, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26021
Compact LTCC bandpass filter with vertically folded structure
Authors: Chin Kuo‐Sheng , Hung Jian‐Luen , Huang Chun‐Wei , Fu Jeffrey S. , Karmakar Nemai C.
Published: March 2011

This work designs miniaturized stub‐type microstrip bandpass filters and develops a novel vertical interconnection scheme in a multilayer structure to design vertically folded filters for size reduction. The current study exploits the fabrication process of low‐temperature cofired ceramic (LTCC) for filter realization and fabricates two LTCC Chebyshev stub‐type filters at 28 GHz and 5.8 GHz to verify effectiveness of the proposed structure with a maximum size reduction of 50%. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1389–1394, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26024
Experimental performance evaluation of multi‐echo ICNE pulse sequence in magnetic resonance electrical impedance tomography
Authors: Minhas Atul S. , Jeong Woo Chul , Kim Young Tae , Han Yeqing , Kim Hyung Joong , Woo Eung Je
Published: March 2011

Latest experimental results in magnetic resonance electrical impedance tomography (MREIT) demonstrated high‐resolution in vivo conductivity imaging of animal and human subjects using imaging currents of 5 to 9 mA. Externally injected imaging currents induce magnetic flux density distributions, which are affected by a conductivity distribution. Since we extract the induced magnetic flux density images from MR phase images, it is essential to reduce noise in the phase images. In vivo human and disease model animal experiments require reduction of imaging current amplitudes and scan times. In this article, we investigate a multi‐echo based MREIT pulse sequence where we utilize a remaining time after the first echo within one TR to obtain more echo signals. It also allows us to prolong the total current injection time. From phantom and animal imaging experiments, we found that this method significantly reduces the noise level in measured magnetic flux density images. We describe experimental validation of the multi‐echo sequence by comparing its performance with a single‐echo method using 3 mA imaging currents. The proposed method will be advantageous for an imaging region with long T2 values such as the brain and knee. Depending on T2 values, we suggest using two or three echoes in future experimental studies. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Simulation and optimization of pulsed radio frequency irradiation scheme for chemical exchange saturation transfer (CEST) MRI—demonstration of pH‐weighted pulsed‐amide proton CEST MRI in an animal model of acute cerebral ischemia
Authors: Sun Phillip Zhe , Wang Enfeng , Cheung Jerry S. , Zhang Xiaoan , Benner Thomas , Sorensen A. Gregory
Published: March 2011

Chemical exchange saturation transfer (CEST) magnetic resonance imaging (MRI) is capable of measuring dilute labile protons and microenvironmental properties. However, the CEST contrast is dependent upon experimental conditions—particularly, the radiofrequency (RF) irradiation scheme. Although continuous‐wave RF irradiation has been used conventionally, the limited RF pulse duration or duty cycle of most clinical systems requires the use of pulsed RF irradiation. Here, the conventional numerical simulation is extended to describe pulsed‐CEST MRI contrast as a function of RF pulse parameters (i.e., RF pulse duration and flip angle) and labile proton properties (i.e., exchange rate and chemical shift). For diamagnetic CEST agents undergoing slow or intermediate chemical exchange, simulation shows a linear regression relationship between the optimal mean RF power of pulsed‐CEST MRI and continuous‐wave‐CEST MRI. The optimized pulsed‐CEST contrast is approximately equal to that of continuous‐wave‐CEST MRI for exchange rates less than 50 s−1, as confirmed experimentally using a multicompartment pH phantom. In the acute stroke animals, we showed that pulsed‐ and continuous‐wave‐amide proton CEST MRI demonstrated similar contrast. In summary, our study elucidated the RF irradiation dependence of pulsed‐CEST MRI contrast, providing useful insights to guide its experimental optimization and quantification. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
In vivo noninvasive 4D pressure difference mapping in the human aorta: Phantom comparison and application in healthy volunteers and patients
Authors: Bock Jelena , Frydrychowicz Alex , Lorenz Ramona , Hirtler Daniel , Barker Alex J. , Johnson Kevin M. , Arnold Raoul , Burkhardt Hans , Hennig Juergen , Markl Michael
Published: March 2011

In this work, we present a systematic phantom comparison and clinical application of noninvasive pressure difference mapping in the human aorta based on time‐resolved 3D phase contrast data. Relative pressure differences were calculated based on integration and iterative refinement of pressure gradients derived from MR‐based three‐directional velocity vector fields (flow‐sensitive 4D MRI with spatial/temporal resolution ∼ 2.1 mm3/40 ms) using the Navier‐Stokes equation. After in vitro study using a stenosis phantom, time‐resolved 3D pressure gradients were systematically evaluated in the thoracic aorta in a group of 12 healthy subjects and 6 patients after repair for aortic coarctation. Results from the phantom study showed good agreement with expected values and standard methods (Bernoulli). Data of healthy subjects showed good intersubject consistency and good agreement with the literature. In patients, pressure waveforms showed elevated peak values. Pressure gradients across the stenosis were compared with reference measurements from Doppler ultrasound. The MRI findings demonstrated a significant correlation (r = 0.96, P < 0.05) but moderate underestimation (14.7% ± 15.5%) compared with ultrasound when the maximum pressure difference for all possible paths connecting proximal and distal locations of the stenosis were used. This study demonstrates the potential of the applied approach to derive additional quantitative information such as pressure gradients from time‐resolved 3D phase contrast MRI. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Numerical modeling and neural networks to identify model parameters from piezocone tests: II. Multi‐parameter identification from piezocone data
Authors: Obrzud Rafał F. , Truty Andrzej , Vulliet Laurent
Published: March 2011

This paper completes the study presented in the accompanying paper, and demonstrates a numerical algorithm for parameter prediction from the piezocone test (CPTU) data. This part deals with a development of neural network (NN) models which are able to map multi‐variable input data onto typical geotechnical characteristics and constitutive parameters of the modified Cam clay model, which has been applied in this study. The identification procedure is designed for the coupled hydro‐mechanical boundary value problem in normally‐and lightly overconsolidated clayey soils including partially drained conditions that may appear during cone penetration. The NN models are trained with pseudo‐experimental measurements derived with the aid of the numerical model of the piezocone test, presented in the accompanying paper. Different input configurations containing CPTU measurements and some complementary data are studied with respect to the accuracy of predicted parameter values. Finally, the performance of the developed NN predictors is tested with field CPTU data which are derived from three well‐documented characterization sites, and the obtained predictions are compared with benchmark laboratory results. Copyright © 2011 John Wiley & Sons, Ltd.
Reinforcement of hydrogel by addition of fiber‐like nanofiller
Authors: Shikinaka Kazuhiro , Koizumi Yumi , Osada Yoshihito , Shigehara Kiyotaka
Published: March 2011

Reinforcement of acrylamide (AAm) gel was achieved by addition of imogolite (IG), rigid tube‐like nanofiller. The obtained gel exhibits high mechanical strength depending on cross‐linking density of AAm. Especially, when cross‐linker is 0.5 mol% to AAm, the compressive fracture stress of gel is 17 MPa which is approximately 60 times higher than conventional AAm gels. Copyright © 2011 John Wiley & Sons, Ltd.
Photo‐reversible oxygen binding of a cobalt schiff‐base complex with an axially coordinating photo‐isomerizable polymer ligand
Authors: Suzuki Takayuki , Suzuki Yosuke , Hachisu Kiyozumi , Shinozaki Hiraku
Published: March 2011

The reversible binding of oxygen to N,N′‐ethylene bis(salicylideneiminato) cobalt(II) (CoS), to which a photo‐isomerizable naphthalenyl vinylpyridine residue of copolymer 1 coordinated, was investigated. The E form of the naphthalenyl vinylpyridine residues coordinating to CoS, (E)‐1‐CoS, showed photo‐reversible isomerization into the Z form, (Z)‐1‐CoS, on direct ultraviolet (UV) irradiation in a range of 335–345 nm and vice versa on another UV irradiation in a range of 285–295 nm. Reversible change of oxygen‐binding affinity of 1‐CoS corresponding to the photo‐reversible E/Z isomerization of the naphthalenyl vinylpyridine residues was also observed in absorption spectra. Steric hindrance of the polymer chain of 1 on the coordination of the naphthalenyl vinylpyridine residue of (Z)‐1 to CoS was thought to cause the decrease of oxygen‐binding affinity of (Z)‐1‐CoS. Copyright © 2011 John Wiley & Sons, Ltd.
Synthesis of high performance, conductive PEDOT‐coated polyester yarns by OCVD technique
Authors: Bashir Tariq , Skrifvars Mikael , Persson Nils‐Krister
Published: March 2011

Production of high performance conductive textile yarn fibers for different electronic applications has become a prominent area of many research groups throughout the world. We have used oxidative chemical vapor deposition (OCVD) technique to coat flexible and high strength polyester yarns with conjugated polymer, poly(3,4‐ethylenedioxythiophene) (PEDOT) in presence of ferric (III) chloride (FeCl3) oxidant. OCVD is an efficient solvent free technique used to get uniform, thin, and highly conductive polymer layers on different substrates. In this paper, PEDOT‐coated polyester (PET) yarns were prepared under specific reaction conditions, and the electrical, mechanical and thermal properties were compared to previously studied PEDOT‐coated viscose yarns. Scanning electron microscopy (SEM) and FT‐IR analysis revealed that polymerization of PEDOT on the surface of the polyester yarns has been taken place successfully and structural analysis showed that PEDOT has strong interactions with viscose yarns as compared to PET yarns. The voltage–current (V–I) characteristics showed that PET yarns are more conductive than PEDOT‐coated viscose yarns. The variation in the conductivity of PEDOT‐coated yarns and the heat generation properties during the flow of current through coated yarns for longer period of time, was studied by time–current (t–I) characteristics. Thermogravimeteric analysis (TGA) was employed to investigate the thermal properties and the amount of PEDOT in PEDOT‐coated PET yarns compared to PEDOT‐coated viscose. The effect of PEDOT coating and ferric (III) chloride concentration on the mechanical properties of coated yarns was evaluated by tensile testing. The obtained PEDOT‐coated conductive polyester yarns could be used in smart clothing for medical and military applications. Copyright © 2011 John Wiley & Sons, Ltd.
Paradoxical effects of T‐cadherin on squamous cell carcinoma: up‐ and down‐regulation increase xenograft growth by distinct mechanisms
Authors: Pfaff Dennis , Philippova Maria , Kyriakakis Emmanouil , Maslova Kseniya , Rupp Katharina , Buechner Stanislaw A , Iezzi Giandomenica , Spagnoli Giulio C , Erne Paul , Resink Therese J
Published: March 2011

Mechanisms underlying cutaneous squamous cell carcinoma (SCC) tumour growth and invasion are incompletely understood. Our previous pathological and in vitro studies suggest that cell surface glycoprotein T‐cadherin (T‐cad) might be a controlling determinant of the behaviour of SCC. Here we used a murine xenograft model to determine whether T‐cad modulates SCC tumour progression in vivo. Silencing or up‐regulation of T‐cad in A431 (shTcad or Tcad+, respectively) both resulted in increased tumour expansion in vivo. To explain this unanticipated outcome, we focused on proliferation, apoptosis and angiogenesis/lymphangiogenesis, which are important determinants of the progression of solid tumours in vivo. shTcad exhibited enhanced proliferation potential in vitro and in vivo, and their signalling response to EGF was characterized by a higher Erk1/2:p38MAPK activity ratio, which has been correlated with more aggressive tumour growth. T‐cad over‐expression did not affect proliferation but staining for cleaved caspase 3 revealed a minimal occurrence of extensive apoptosis in Tcad+ tumours. Immunofluoresence staining of xenograft sections revealed increased intra‐tumoural total microvessel (CD31+) and lymphatic vessel (LYVE‐1+) densities in Tcad+ tumours. shTcad tumours exhibited decreased microvessel and lymphatic densities. Tcad+ expressed higher levels of transcripts for VEGF‐A, VEGF‐C and VEGF‐D in vitro and in vivo. Culture supernatants collected from Tcad+ enhanced sprout outgrowth from spheroids composed of either microvascular or lymphatic endothelial cells, and these in vitro angiogenic and lymphangiogenic responses were abrogated by inclusion of neutralizing VEGF antibodies. We conclude that T‐cad can exert pleiotropic effects on SCC progression; up‐ or down‐regulation of T‐cad can promote SCC tumour expansion in vivo but through distinct mechanisms, namely enhancement of angio/lymphangiogenic potential or enhancement of proliferation capacity. Copyright © 2011 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Active site mutant dimethylarginine dimethylaminohydrolase 1 expression confers an intermediate tumour phenotype in C6 gliomas
Authors: Boult Jessica KR , Walker‐Samuel Simon , Jamin Yann , Leiper James M , Whitley Guy St J , Robinson Simon P
Published: March 2011

Dimethylarginine dimethylaminohydrolase (DDAH) metabolizes the endogenous inhibitor of nitric oxide synthesis, asymmetric dimethylarginine (ADMA). Constitutive over‐expression of DDAH1, the isoform primarily associated with neuronal nitric oxide synthase (nNOS) results in increased tumour growth and vascularization, and elevated VEGF secretion. To address whether DDAH1‐mediated tumour growth is reliant upon the enzymatic activity of DDAH1, cell lines expressing an active site mutant of DDAH1 incapable of metabolizing ADMA were created. Xenografts derived from these cell lines grew significantly faster than those derived from control cells, yet not as fast as those over‐expressing wild‐type DDAH1. VEGF expression in DDAH1 mutant‐expressing tumours did not differ from control tumours but was significantly lower than that of wild‐type DDAH1‐over‐expressing tumours. Fluorescence microscopy for CD31 and pimonidazole adduct formation demonstrated that DDAH1 mutant‐expressing tumours had a lower endothelial content and demonstrated less hypoxia, respectively, than wild‐type DDAH1‐expressing tumours. However, there was no difference in uptake of the perfusion marker Hoechst 33342. Non‐invasive multiparametric quantitative MRI, including the measurement of native T1 and T2 relaxation times and apparent water diffusion coefficient, was indicative of higher cellularity in DDAH1‐expressing xenografts, which was confirmed by histological quantification of necrosis. C6 xenografts expressing active site mutant DDAH1 displayed an intermediate phenotype between tumours over‐expressing wild‐type DDAH1 and control tumours. These data suggest that enhanced VEGF expression downstream of DDAH1 was dependent upon ADMA metabolism, but that the DDAH1‐mediated increase in tumour growth was only partially dependent upon its enzymatic activity, and therefore must involve an as‐yet unidentified mechanism. DDAH1 is an important mediator of tumour progression, but appears to have addition roles independent of its metabolism of ADMA, which need to be considered in therapeutic strategies targeted against the NO/DDAH pathway in cancer. Copyright © 2011 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Risk of recurrence and survival after relapse in patients with Ewing sarcoma
Authors: Stahl Martin , Ranft Andreas , Paulussen Michael , Bölling Tobias , Vieth Volker , Bielack Stefan , Görtitz Irene , Braun‐Munzinger Gabriele , Hardes Jendrik , Jürgens Heribert , Dirksen Uta
Published: March 2011

Background

The prognosis in patients with relapsed Ewing sarcoma is unfavorable. Our investigation identifies factors predicting for the outcome following relapse.

Procedure

We analyzed type of relapse, time to relapse and overall survival after relapse (OSr) in 714 patients with first recurrence. All patients had been treated within the Cooperative Ewing Sarcoma Studies (CESS) 81 or 86, or the European Intergroup CESS (EICESS 92). OSr time was calculated from diagnosis of first relapse to last follow‐up or death.

Results

Median follow‐up time from diagnosis of primary disease was 2.2 years (mean = 4.0; range: 0.2–24.9). Relapse sites were local in 15%, combined local and systemic in 12%, and systemic in 73%. Among patients with a localized primary tumor, 20% relapsed locally, while 12% showed combined and 68% systemic relapse. When the primary disease was disseminated, 82% developed systemic, 13% combined, and 5% local relapse. Five‐year OSr was 0.13 (SE = 0.01). Outcome following local relapse, with a 5‐year survival rate of 0.24 (P < 0.001), was superior to outcome after systemic or combined recurrence. Five‐year OSr was 0.07 (SE = 0.01) in patients who relapsed 0–2 years after the diagnosis of primary disease, as compared to a 5‐year OSr of 0.29 (SE = 0.03) when relapse occurred later.

Conclusions

5‐year OSr in Ewing sarcoma is poor (<0.2). Prognostically favorable factors are: late onset (>2 years) and strictly localized relapse. Pediatr Blood Cancer 2011; 57: 549–553. © 2011 Wiley‐Liss, Inc.
Determination of carbohydrates in medicinal plants‐comparison between TLC, mf‐MELDI‐MS and GC‐MS
Authors: Qureshi Muhammad Nasimullah , Stecher Guenther , Sultana Tahira , Abel Gudrun , Popp Michael , Bonn Guenther K.
Published: March 2011

Introduction – Quality control in the pharmaceutical and phytopharmaceutical industries requires fast and reliable methods for the analysis of raw materials and final products.

Objective – This study evaluates different analytical approaches in order to recognise the most suitable technique for the analysis of carbohydrates in herbal drug preparations.

Methodology – The specific focus of the study is on thin‐layer chromatography (TLC), gas chromatography (GC), and a newly developed mass spectrometric method, i.e. matrix free material enhanced laser desorption/ionisation time of flight mass spectrometry (mf‐MELDI‐MS). Samples employed in the study were standards and microwave‐assisted water extracts from Quercus.

Results – TLC analysis proved the presence of mono‐, di‐ and trisaccharides within the biological sample and hinted at the existence of an unknown carbohydrate of higher oligomerisation degree. After evaluation of different derivatisation techniques, GC‐MS confirmed data obtained via TLC for mono‐ to trisaccharides, delivering additionally quantified values under a considerable amount of time. A carbohydrate of higher oligomerisation degree could not be found. The application of mf‐MELDI‐MS further confirmed the presence of carbohydrates up to trisaccharides, also hinting at the presence of a form of tetrasaccharide. Besides this information, mf‐MELDI‐MS delivered further data about other substances present in the extract. Quantitative determination resulted in 1.750, 1.736 and 0.336 mg/mL for glucose, sucrose and raffinose respectively.

Conclusion – Evaluation of all three techniques employed, clearly proved the heightened performance of mf‐MELDI‐MS for the qualitative analysis of complex mixtures, as targets do not need modification and analysis requires only a few minutes. In addition, GC‐MS is suitable for quantitative analysis. Copyright © 2011 John Wiley & Sons, Ltd.
Design, synthesis and characterization of a peptide able to bind proteins of the KCTD family: implications for KCTD—cullin 3 recognition
Authors: Pirone Luciano , Correale Stefania , Paola Ivan de , Zaccaro Laura , Simone Giuseppina De , Vitagliano Luigi , Pedone Emilia , Gaetano Sonia Di
Published: March 2011

Pox virus Zinc/Bric‐à‐brac, Tramtrack and Broad (POZ/BTB) is a widespread domain detected in proteins involved in a variety of biological processes. Human genome analyses have unveiled the presence of POZ/BTB domain in a class of proteins (KCTD) whose role as important players in crucial biological processes is emerging. The development of new molecular entities able to interact with these proteins and to modulate their activity is a field of relevant interest. By using molecular modeling and literature mutagenesis analyses, we here designed and characterized a peptide that is able to interact with submicromolar affinities with two different members (KCTD11 and KCTD5) of this family. This finding suggests that the tetrameric KCTD11 and the pentameric KCTD5 are endowed with a similar cavity at the subunit–subunit interface deputed to the Cul3 binding, despite their different oligomeric states. Copyright © 2011 European Peptide Society and John Wiley & Sons, Ltd.
Comparative Study of Spasmolytic Properties, Antioxidant Activity and Phenolic Content of Arbutus unedo from Montenegro and Greece
Authors: Pavlović Dragana R. , Branković Suzana , Kovačević Nada , Kitić Dušanka , Veljković Slavimir
Published: March 2011

Arbutus unedo leaf is used traditionally for gastrointestinal complaints. Ethanol extracts from Arbutus unedo collected in both Montenegro (AuM) and Greece (AuG) were found to decrease the ileal basal tonus, with AuG producing a significantly higher (p < 0.05) reduction in contractile response to acetylcholine. AuM and AuG relaxed 80 mm K+ induced contractions and shifted the Ca++ concentration–response curves to the right, similar to that caused by verapamil, suggesting that the spasmolytic effect was induced through calcium channel inhibition. The antioxidant activity of AuM and AuG and the phenolic content of the extracts and dry plant material were studied, and both extracts were found to possess considerable antioxidant properties. AuG showed a stronger in vitro antioxidative activity in the DPPH assay and in the TBA test. Polyphenol, tannin and flavonoid levels were higher in AuG, supporting the more potent spasmolytic and antioxidative effects, whereas the arbutin content was higher in dry plant material collected in Montenegro. Copyright © 2011 John Wiley & Sons, Ltd.
Antiproliferative Alkaloids from Crinum zeylanicum
Authors: Berkov Strahil , Romani Stefania , Herrera Maria , Viladomat Francesc , Codina Carles , Momekov Georgi , Ionkova Iliana , Bastida Jaume
Published: March 2011

Crinum zeylanicum is used in folk medicine as a rubefacient in rheumatism, a treatment for malaria or as a poison. Complex alkaloid profiles in C. zeylanicum plant organs were revealed by GC‐MS analysis, including several bioactive compounds. Crinine, lycorine, 11‐O‐acetoxyambelline, ambelline, 6‐hydroxybuphanidrine and 6‐ethoxybuphanidrine (an artefact of the isolation procedure) were isolated. Crinine, 6‐hydroxybuphanidrine and 6‐ethoxybuphanidrine showed antiproliferative effects against human tumor cell lines, crinine being the most active (IC50 14.04 μm against HL‐60/Dox). The latter compound induced apoptosis in a dose‐dependent manner in HL‐60 and MDA‐MB‐231 cell lines. Structure‐activity relationships in the studied molecules indicated that the hydrogenation of the double bond at C1‐C2 leads to a loss of activity, whereas substitutions at C6, C8 and C11 affect their cytotoxicity. Copyright © 2011 John Wiley & Sons, Ltd.
ENVIRONMENTAL DETERMINANTS OF WATER QUALITY IN BOREAL RIVERS BASED ON PARTITIONING METHODS
Authors: Varanka S. , Luoto M.
Published: March 2011

Quantitative studies of the relationships between river water quality and environmental variables are needed to improve understanding of the impacts of natural and human factors on aquatic environments. However, multicollinearity between environmental variables can hinder the identification of key factors when water quality–environment relationship is studied using traditional regression methods. This study utilized two alternative statistical methods, variation and hierarchical partitioning, to address these difficulties in studies of river water quality. Using these methods, we explored the effects of catchment physiography, climate and land use variables on total phosphorus and nitrogen, pH, water colour and dissolved oxygen during the years 1995–2005 in 32 boreal rivers in Finland.

Catchment physiography and land use explained most of the variation in water quality, especially in phosphorus, nitrogen and water colour data. The strong correlations (rs > 0.8) between agricultural land use and phosphorus and nitrogen concentrations indicate that water quality is highly affected by agriculture in boreal regions. By determining the environmental drivers of different water quality variables, we can estimate the water quality of different catchments in response to environmental changes and identify areas that are sensitive to global changes. Our study shows that novel statistical methods integrated with geographic information system data and techniques provide deeper insights into water quality–environment relationships than traditional regression, and these should be considered when developing, for example, conservation planning for rivers. Copyright © 2011 John Wiley & Sons, Ltd.
Linearity of the instrumental intensity scale in TOF‐SIMS—a VAMAS interlaboratory study
Authors: Lee J. L. S. , Gilmore I. S. , Seah M. P.
Published: March 2011

A VAMAS interlaboratory study involving 21 time‐of‐flight SIMS instruments from nine countries has been conducted to evaluate the linearity of the instrumental intensity scale and procedures for intensity correction. Analysts were supplied, by National Physical Laboratory (NPL), with a protocol for analysis (closely aligned with ISO 23830) together with a reference material of polytetrafluoroethylene (PTFE) tape. The primary ion beam current is varied to provide secondary ion intensities that span the linear to nonlinear regime. The natural carbon isotope ratios 12CxFy+/13C12Cx−1Fy+ for five peaks are used to evaluate the linearity, without a need to measure the ion beam current. A method is given for determining the linearity as a function of secondary ion intensity, with and without dead time correction. It is found that single ion counting statistics is closely obeyed, and the linearity achievable is generally excellent with careful application of dead time correction. Three quarters of instruments in the study achieved better than 95% linearity at a count rate of 0.8 measured counts per pulse, equivalent to 1.6 secondary ions impinging the detector per primary ion pulse. We discuss factors affecting linearity and the precise application of dead time correction and give guidance for practical analysis. This includes suboptimal detector efficiency, inhomogeneous intensities across the rastered area, inadequate charge compensation, and the choice of peak integration limits. The interlaboratory study shows that the method to determine linearity is generally applicable, robust and provides an excellent basis for the development of an ISO standard. © Crown copyright 2011. Reproduced with the permission of Her Majesty's Stationery Office. Published by John Wiley & Sons, Ltd.
In‐Situ Measurement of CO‐ and CO2‐Concentrations in BOF Off‐Gas
Authors: Sandlöbes S. , Senk D. , Sancho L. , Diaz A.
Published: March 2011

Improvement of the efficiency and productivity of steelmaking requires accurate and real‐time process information to precisely adjust the tapping conditions. The response time of BOF process control systems is commonly depending on the time needed for off‐gas sampling and analysis.

A FTIR based measurement system was adapted and installed at an industrial steel converter of ArcelorMittal España S.A. in Aviles. An advanced data interpretation routine based on the quantum mechanical fundamentals of remote infrared (IR) spectroscopy was developed to enable precise determination of the {CO}‐ and {CO2}‐concentrations, resp. their ratio, in the off‐gas.

The results of the industrial measurement showed the ability of the FTIR based system for real‐time measurement of temperature, {CO}‐ and {CO2}‐concentrations in the hot and dusty off‐gas. The influence of dust at the chosen defined optical path lengths in the IR wavelengths region can be neglected, but the collector lens clean has to be kept clean.
Polynomial approximation to universal ionisation cross‐sections of K and L shells induced by H and He ion beams
Authors: Taborda A. , Chaves P. C. , Reis M. A.
Published: March 2011

In 1970s, Basbas et al.(Phys. Rev. A 1973, 7, 983; Phys. Rev. A 1978, 17, 1655) rose the possibility that PWBA ionisation cross‐sections could be expressed in terms of a universal ionisation cross‐section. Starting from ECPSSR ionisation cross‐sections and reproducing Basbas approach, a universal curve can be displayed against the reduced ion velocity, but data are too widespread to allow for a proper polynomial fit. In the present work, Basbas approach was revised and plotted against a rescaled, reduced ion velocity, eliminating most of the data spread and generating in practice a universal ionisation cross‐section curve. In this revised approach, the screening parameter, θn, o, assumes a major role in reaching the universal behaviour. Polynomial approximations are then made to the universal curves for incident H+ and He2+ ions. Cross‐sections were then calculated using the polynomial approximations for target elements with atomic number from 11 to 92 and for ion beam energies from 50 keV to 10 MeV, for K‐ and L‐shell ionisation cross‐sections and are compared to experimental data from literature. Finally, X‐ray yields were simulated for various thick target samples using these polynomial approximations and the outcomes are compared to data obtained at the ITN PIXE set‐up. Copyright © 2011 John Wiley & Sons, Ltd.
Pentamethylcyclopentadienyl(η6‐cyclooctatrienyl)ruthenium Tetrachlorozincate, [RuCp*(η6‐C8H10)]2ZnCl4
Authors: Bruce Michael I. , Joly Damien , Skelton Brian W. , White Allan H.
Published: March 2011

The crystal and molecular structures of the title compound, the first for a complex of the type [RuCp*(η6‐C8‐ring)]+, is presented, the material being obtained serendipitously from a reaction between RuCl(cod)Cp* and 1‐ferrocenylbuta‐1,3‐diyne in the presence of ZnCl2.  (2.21 Å) is appreciably longer than in RuCp*2 (2.18 Å) and similar to the value for the Ru‐η6 component (2.22 Å).
Gemischte Tristannide der Reihe CaSn3 – SrSn3 – BaSn3: Synthesen, Kristallstrukturen, Chemische Bindung
Authors: Wendorff Marco , Röhr Caroline
Published: March 2011

Ternary mixed Ca/Sr/Ba tristannides of overall composition ASn3 (A = Ca, Sr, Ba) were synthesized from mixtures of the elements. The structures of the compounds were determined by means of single‐crystal X‐ray data or Rietveld powder refinements. All structures exhibit close packed ordered ASn3 layers containing Sn Kagomé nets, which are stacked in different orientations. Depending on the stacking sequences, the resulting tin polyanion resembles the oxygen nets of the cubic (corner sharing octahedra, c stacking, Cu3Au‐type structure, i.e. CaSn3) or of the hexagonal perovskites (face sharing octahedra, h stacking, Ni3Sn‐type structure, i.e. BaSn3). In the binary compound CaSn3 (Cu3Au‐type) up to 46(5) % of calcium can be substituted against strontium (cubic, space group Pm$\bar{3}$m, a = 479.75(3), Z = 1, RP = 0.0587, RBragg = 0.0343). The known binary phase SrSn3 forms the Mg3In structure type with a (hhcc)3 stacking sequence and exhibits no noticeable phase width. A small partial substitution of strontium, against barium (Sr0.91(2)Ba0.09(2)Sn3 to Sr0.81(2)Ba0.19(2)Sn3: trigonal, space group R$\bar{3}$m, a = 698.9(2)/701.21(14), c = 2472.4(10)/2465.0(7) pm, Z = 9, R1 = 0.0637/0.0738) causes the packing to switch to the (hhc)3 stacking of the TaCo3‐type structure. At a Ba proportion of 26(2) % (Sr0.74(2)Ba0.26(2)Sn3: hexagonal, space group P63/mmc, a = 704.21(12), c = 2197.6(5) pm, Z = 8, R1 = 0.0705) a further structure change to the BaSn2.57Bi0.43 structure type ((hhhc)2‐stacking) occurs. The series is terminated with the pure h stacking of BaSn3, the stability range of which starts at the composition Sr0.22(2)Ba0.78(2)Sn3 (hexagonal, space group P63/mmc; a = 717.92(12), c = 548.15(10) pm, Z = 2, R1 = 0.0297). As easily noted from this series, the stacking sequence depends on the ratio of the atomic radii of the contributing atoms/ions. The observed trend can be rationalized by the decreasing coordination number of tin when going from c to h stacking. Covalent as well as metallic aspects of the chemical bonding in the tristannides are discussed on the basis of the results of FP‐LAPW calculations (density of states, band structure and valence electron densities).
Long‐Term Administration of Cod Liver Oil Ameliorates Cognitive Impairment Induced by Chronic Stress in Rats
Authors: Trofimiuk Emil , Braszko Jan J.
Published: March 2011

Cod liver oil (CLO) is a rich source of omega‐3 fatty acids (FA), especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The existing data suggest that EPA and DHA are the active agents of fish oil. In this study, we tested a hypothesis that the active constituents of CLO alleviate the negative impact of prolonged restraint stress on cognitive functions of male Wistar rats. Specifically, we attempted to characterize the preventive action of long‐lasting treatment with CLO [0.375 ml/100 g body weight (equivalent to a dose of 300 mg/kg DHA and 225 mg/kg EPA), p.o. for 21 days] against an impairment caused by chronic restraint stress (2 h daily for 21 days) on recall as tested in a passive avoidance situation and on the spatial reference and working memory tested in a Barnes maze as well as on locomotor activity and anxiety behavior tested respectively in an open field and elevated plus‐maze. We found that CLO administration statistically significantly (p < 0.01, both) prevented the deleterious effects of chronic restraint stress on recall and the spatial memory.
Oxidation of Crude Corn Oil with and without Elevated Tocotrienols
Authors: Dolde David , Wang Tong
Published: March 2011

Kernels and oil from corn with increased concentrations of tocotrienols (T3) due to the transgenic expression of a homogentisic acid geranylgeranyl transferase (HGGT) gene from two growing years were characterized for tocol and fatty acid compositions. The crude extracted oil was analyzed for oxidative properties and compared to non‐transformed material derived from the plants grown at the same location and during the same year. No significant difference was observed in composition of major fatty acids. Both the seed (kernel) and extracted crude oil from the HGGT expressing corn had a 18‐fold increase in tocotrienol content from 300 to 5,400 ppm in oil. There was a concurrent 18% decrease in tocopherol content, 1,150 ppm total tocopherols in control oil declining to 940 ppm in HGGT oil. Although tocopherols and tocotrienols are generally considered antioxidants, they may exhibit prooxidant effects at higher concentrations and they should be tested. Crude oil was extracted from control and transformed corn produced during 2005 and 2006 yielding four oil samples that were evaluated for their oxidative properties. The formation of lipid hydroperoxides, a primary oxidation product, was evaluated at 60 °C over 9 days by measuring the peroxide value (PV). Resistance to oxidation or induction period (IP) was measured using an Oxidative Stability Instrument. There was a slight decrease in hydroperoxide formation in the HGGT oil compared to the corresponding control but was less than the year to year differences. The induction period was the same for the 2005 oils, with or without the increased tocotrienol content, but the crude oil with enhanced tocotrienol had a longer IP than the control crude oil in the 2006 samples.
In vitro experiments reconstituting topographic map formation
Authors: Gebhardt C. , Weth F. , Bastmeyer M.
Published: March 2011

Topographic axonal projections are a prev­alent feature of brain connectivity. The ret­inotectal mapping of the chick is the best-studied model system of this type of neuro­nal connectivity. Its formation is common­ly explained by interactions between grad­ed markers of the ephrin-A/EphA family ex­pressed on both retinal ganglion cell growth cones and on the tectal target area. Surpris­ingly, most insights into retinotectal devel­opment have been gathered through in vitro rather than in vivo experiments. In vitro as­says not only enabled the biochemical iden­tification of the postulated molecular mark­ers but also helped to understand the signals conveyed by them. Thus, it was established in vitro that forward (ephrin-A->EphA) as well as reverse signalling (EphA->ephrin-A) are si­multaneously needed for topographically ap­propriate guidance of retinal axons. However, no in vitro assay yet exists that fully reproduc­es topography formation. New in vitro tech­niques such as micro-contact printing or mi­cro-fluidic networks may help to improve ex­istent assays and to identify a sufficient set of functional components that reconstitutes to­pography formation.
ASSESSING THE RISK OF ROOT ROTS IN COMMON BEANS IN EAST AFRICA USING SIMULATED, ESTIMATED AND OBSERVED DAILY RAINFALL DATA
Authors: FARROW ANDREW , MUSONI DIDACE , COOK SIMON , BURUCHARA ROBIN
Published: March 2011

This paper seeks to establish the concept that the analysis of high temporal resolution meteorological data adds value to the investigation of the effect of climatic variability on the prevalence and severity of agricultural pests and diseases. Specifically we attempt to improve disease potential maps of root rots in common beans, based on a combination of inherent susceptibility and the risk of exposure to critical weather events. We achieve this using simulated datasets of daily rainfall to assess the probability of heavy rainfall events at particular times during the cropping season. We then validate these simulated events with observations from meteorological stations in East Africa. We also assess the utility of remotely sensed daily rainfall estimates in near real time for the purposes of updating the risks of these events over large areas and for providing warnings of potential disease outbreaks. We find that simulated rainfall data provide the means to assess risk over large areas, but there are too few datasets of observed rainfall to definitively validate the probabilities of heavy rainfall events generated using rainfall simulations such as those generated by MarkSim. We also find that selected satellite rainfall estimates are unable to predict observed rainfall events with any power, but data from a sufficiently dense network of rain gauges are not available in the region. Despite these problems we show that remotely sensed rainfall estimates may provide a more realistic assessment of rainfall over large areas where rainfall observations are not available, and alternative satellite estimates should be explored.