bluuebunny/crossref_metadata_2025 huggingface dataset:
The geoarchaeological and paleoenvironmental context of Paleoindian sites in western Middle Park, Colorado, USA
Authors: Mayer James H. , Reider Richard G. , Kornfeld Marcel
Published: February 2010

Geoarchaeological investigations in western Middle Park provide important information for understanding the soil‐stratigraphic context of Paleoindian components, as well as the latest Quaternary environmental change and landscape evolution in a Southern Rocky Mountain intermontane basin. Paleoindian components are associated with the oldest two of four latest Quaternary stratigraphic units (1–4) recognized in co‐alluvial mantles (combined slopewash and colluvium) in uplands and in alluvial valley fills. Limited data suggest accumulation of unit 1 as early as ∼12,500 14C yr B.P. in alluvial valleys and by at least ∼11,000 14C yr B.P. in uplands was followed by brief stability and soil formation. A relatively widespread disconformity marks earliest Holocene erosion and substantial removal of latest Pleistocene deposits in upland and alluvial settings followed by unit 2 deposition ∼10,000–9000 14C yr B.P., perhaps signaling the abrupt onset of an intensified summer monsoon. In situ Paleoindian components in uplands are found in a moderately developed buried soil (the Kremmling soil) formed in units 1 and 2 in thin (≤1m) hillslope co‐alluvial mantles. The Kremmling soil reflects geomorphic stability in upland and alluvial settings ∼9000–4500 14C yr BP, and represents a buried landscape with the potential to contain additional Paleoindian components, although elsewhere in western Middle Park Early Archaic components are documented in morphologically similar soils. Kremmling soil morphology, the relative abundance of charcoal in unit 2 relative to younger units, and charcoal morphology indicate the expansion of forest cover, including Pinus, and grass cover during the early and middle Holocene, suggesting conditions moister than present. © 2010 Wiley Periodicals, Inc.
Morphological and geochemical analysis of the Laguna Blanca/Zapaleri obsidian source in the Atacama Puna
Authors: Seelenfreund Andrea , Pino Mario , Glascock Michael D. , Sinclaire Carole , Miranda Pedro , Pasten Denisse , Cancino Simón , Dinator María Inés , Morales José Roberto
Published: February 2010

This paper describes a large obsidian deposit located along the southern banks of Laguna Blanca, on the eastern slope of the Jarellón volcanic caldera near the Chilean–Bolivian border. The obsidian at this site occurs in flows or sheets of deflated black or reddish to brown pebbles, redeposited on the shores of a lake. Blocks of obsidian are only found around the caldera rim. Here we analyze the shape of the obsidian pebbles and their geochemistry, comparing them with previously published data. The results indicate that the geochemical composition of the samples strongly matches previous analyses of obsidian from cultural contexts. This obsidian source was one of the most important sites of obsidian procurement since at least the Formative Period in the Atacama Puna region. © 2010 Wiley Periodicals, Inc.
New Diarylheptanoids and Kavalactone from Alpinia katsumadaiHayata
Authors: Li Yuan‐Yuan , Chou Gui‐Xin , Wang Zheng‐Tao
Published: February 2010

Two new diarylheptanoids, katsumains A (1) and B (2), and one new kavalactone, katsumadain (3), together with the three known compounds (4E,6E)‐1,7‐diphenylhepta‐4,6‐dien‐3‐one (4), (5R,6E)‐1,7‐diphenyl‐5‐hydroxyhept‐6‐en‐3‐one (5), and cardamonin (6), were isolated from the seeds of Alpinia katsumadai Hayata. Their structures were elucidated mainly by spectroscopic methods (1D‐ and 2D‐NMR) and by mass spectrometry (HR‐ESI‐MS). Besides, the erroneous nomenclatures for (+)‐linderatin and (+)‐neolinderatin as given in [10] [11] were corrected to be 2′,4′,6′‐trihydroxy‐3′‐[(3R,4R)‐4‐isopropyl‐1‐methylcyclohex‐1‐en‐3‐yl]dihydrochalcone for (+)‐linderatin and 2′,4′,6′‐trihydroxy‐3′,5′‐bis[(3R,4R)‐4‐isopropyl‐1‐methylcyclohex‐1‐en‐3‐yl]dihydrochalcone for (+)‐neolinderatin, respectively.
New C27 Steroidal Bisdesmosides from the Fresh Stems of Dracaena cambodiana
Authors: Xu Min , Yang Chong‐Ren , Zhang Ying‐Jun
Published: February 2010

Two new steroidal bisdesmosides, cambodracanosides A and B (1 and 2, resp.), were isolated from the fresh stems of Dracaena cambodiana, together with seven known glycosides. The structures of the new saponins were elucidated on the basis of detailed spectroscopic analyses, including 1D‐ and 2D‐NMR techniques, and acidic hydrolysis.
Spirostanol Saponins from the Fibrous Roots of Ophiopogon japonicus (Thunb.) Ker‐Gawl
Authors: Duan Chang‐Ling , Li Yu‐Juan , Li Peng , Jiang Yong , Liu Jian‐Xun , Tu Peng‐Fei
Published: February 2010

Three new steroidal saponins, (25R)‐ruscogenin‐3‐yl α‐L‐rhamnopyranosyl‐(1→2)‐[β‐D‐xylopyranosyl‐(1→4)]‐β‐D‐glucopyranoside (1), diosgenin‐3‐yl 2‐O‐acetyl‐α‐L‐rhamnopyranosyl‐(1→2)‐[β‐D‐xylopyranosyl‐(1→4)]‐β‐D‐glucopyranoside (2), and pennogenin‐3‐yl 2‐O‐acetyl‐α‐L‐rhamnopyranosyl‐(1→2)‐[β‐D‐xylopyranosyl‐(1→4)]‐β‐D‐glucopyranoside (3) were isolated from the fibrous roots of Ophiopogon japonicus (Thunb.) Ker‐Gawl. Their structures were determined by spectroscopic methods including IR, HR‐ESI‐MS, and 1D‐ and 2D‐NMR. All of these three steroidal saponins exhibited weak cytotoxicities against Hela and Hep2 cell lines.
Four New 1,4‐Benzoquinone Derivatives and One New Coumarin Isolated from Ardisia gigantifolia
Authors: Liu Hongwei , Zhao Yisong , Yang Ruiyun , Zheng Meiqing , Wang Manyuan , Zhang Xue , Qiu Feng , Wang Hengshan , Zhao Feng
Published: February 2010

Four new 1,4‐benzoquinone derivatives, belamcandaquinones J (1), K (2), L (3), and M (4), and one new coumarin, 5, were isolated from the rhizome of Ardisia gigantifolia. Their structures were established by means of spectroscopic methods, and their cytotoxicity was tested in vitro against the cell lines PC‐3, EMT6, A549, Hela, RM‐1, and SGC7901. In comparison with cisplatin, compound 5 showed strong cytotoxicity with an IC50 value of <30 μM against the cell lines PC‐3 and A549. Compounds 1–4 showed no cytotoxicity against all cell lines.
Peroxide/Potassium Iodide Redox Systems for in situ Oxyiodination of Organic Compounds under Liquid‐Phase and Solvent‐Free Conditions
Authors: Venkateshwarlu Gattu , Premalatha Akarapu , Chakradhar Anuganti , Rajanna Kamatala Chinna , Prakash Pondichery Kuppuswamy Sai
Published: February 2010

Iodination of certain aromatic amines and phenols are triggered by the oxidation of KI by peroxy compounds such as tert‐butyl hydroperoxide (tBuOOH) under liquid‐phase and solvent‐free conditions by grinding the reactants in a mortar with a pestle. The reactions afforded corresponding iodo derivatives in good yield with high regioselectivity (Table 1).
New Triterpenoid Saponins from the Roots of Gypsophila paniculata L.
Authors: Yao Shun , Ma Li , Luo Jian‐Guang , Wang Jun‐Song , Kong Ling‐Yi
Published: February 2010

The seven new triterpenoid saponins 1–7 were isolated from the roots of Gypsophila paniculata L. Their structures were established by 1D‐ and 2D‐NMR techniques, HR‐MS, and acid hydrolysis. The isolated compounds include 3,28‐O‐bidesmosides with or without a 4‐methoxycinnamoyl group (see 1 vs. 2 and 3), and 3‐O‐monoglucosides 4–7. All isolated saponins 1–7 and their aglycones were evaluated for their α‐glucosidase inhibition activity. Compound 1 showed inhibitory activity against yeast α‐glucosidase with an IC50 value of 100.9±3.3 μM, whereas compounds 2–7 were inactive.
Two New 7‐Dehydrobrefeldin A Acids from Cylindrocarpon obtusisporum, an Endophytic Fungus of Trewia nudiflora
Authors: Yu Bu‐Zhu , Zhu Na , Du Zhi‐Zhi
Published: February 2010

Two new 7‐dehydrobrefeldin A acids, (2E,4R*)‐4‐hydroxy‐4‐{(1R*,2S*)‐4‐oxo‐2‐[(1E)‐6‐oxohept‐1‐en‐1‐yl]cyclopentyl}but‐2‐enoic acid (3) and (2E,4R*)‐4‐hydroxy‐4‐{(1R*,2S*)‐2‐[(1E,6S*)‐6‐hydroxyhept‐1‐en‐1‐yl]‐4‐oxocyclopentyl}but‐2‐enoic acid (4), were isolated from the endophytic fungal strain Cylindrocarpon obtusisporum (Cooke & Harkness) Wollenw. of Trewia nudiflora, together with two known compounds, 7‐dehydrobrefeldin A (2) and brefeldin A (1). Their structures were determined on the basis of extensive 1D‐ and 2D‐NMR‐spectral analysis.
Tanacetamide D: A New Ceramide from Tanacetum artemisioides
Authors: Hussain Javid , Munir Meamoona , Hassan Zahid , Bano Naseem , Arshad Saima , Ahmad Viqar Uddin
Published: February 2010

One new ceramide (=long‐chain base linked to a fatty acid via an amide bond), tanacetamide D (1), was isolated from Tanacetum artemisioides. Besides this, the two known constituents 5‐demethylnobiletin (2) and 5‐hydroxy‐3,6,7,8,3′,4′‐hexamethoxyflavone (3) were isolated for the first time from this species. The structure elucidation of the isolated compounds were based primarily on 2D‐NMR techniques including correlation spectroscopy (COSY), heteronuclear multiple‐quantum coherence (HMQC), heteronuclear multiple‐bond correlation (HMBC), and nuclear Overhauser effect spectroscopy (NOESY) experiments.
Microwave‐Induced Stereocontrol of β‐Lactam Formation with an N‐Benzylidene‐9,10‐dihydrophenanthren‐3‐amine via Staudinger Cycloaddition
Authors: Bandyopadhyay Debasish , Banik Bimal K.
Published: February 2010

The synthesis of 3‐substituted 4‐phenyl‐1‐(9,10‐dihydrophenanthren‐3‐yl)azetidin‐2‐ones was achieved following Staudinger cycloaddition under microwave‐induced conditions. The stereoselectivity of β‐lactam formation depended on the power level of the microwave irradiation used in the experiments.
Controlled Ethylene Polymerization Catalyzed by Cp$\rm{{_{2}^{\ast}}}$ZrBu2/[Ph3C] [B(C6F5)4]/iBu4Al2O above Room Temperature
Authors: Mathis Déborah , Rouholahnejad Fereshteh , Chen Peter
Published: February 2010

The ternary system composed of Cp$\rm{{_{2}^{\ast}}}$ZrBu2 (Cp*=Me5Cp), [CPh3][B(C6F5)4], and tetraisobutyldialuminoxane (TIBAO) catalyzed the polymerization of ethylene in a controlled fashion at temperatures up to 60 °C. The consumption of ethylene remained constant during the polymerization process, the molecular weight of the polyethylene increased linearly with time, and polydispersity indexes down to 1.3 were obtained. Characterization of the polyethylene by 13C‐NMR and FT‐IR spectroscopy did not indicate any branching or CC linkages, even for polymer produced at 40 °C or above. The linear and saturated polymer structure is due to the absence of β‐hydride transfer, β‐hydride elimination and chain walking during the polymerization. The absence of termination reactions is consistent with the system's demonstrated controlled polymerization.
Drug–Membrane Interaction on Immobilized Liposome Chromatography Compared to Immobilized Artificial Membrane (IAM), Liposome/Water, and Octan‐1‐ol/Water Systems
Authors: Liu Xiangli , Fan Ping , Chen Ming , Hefesha Hossam , Scriba Gerhard K. E. , Gabel Detlef , Fahr Alfred
Published: February 2010

The objective of this study was to investigate drug–membrane interaction by immobilized liposome chromatography (ILC; expressed as lipophilicity index log Ks) and the comparison with lipophilicity indices obtained by liposome/H2O, octan‐1‐ol/H2O, and immobilized artificial membrane (IAM) systems. A set of structurally diverse monofunctional compounds and drugs (nonsteroidal anti‐inflammatory drugs and β‐blockers) were selected in this study. This set of solutes consists of basic or acidic functionalities which are positively or negatively charged at physiological pH 7.4. No correlation was found between log Ks from ILC and lipophilicity indices from any of the other membrane model systems for the whole set of compounds. For structurally related compounds, significant correlations could be established between log Ks from ILC and lipophilicity indices from IAM chromatography and octan‐1‐ol/H2O. However, ILC and liposome/H2O systems only yield parallel partitioning information for structurally related large molecules. For hydrophilic compounds, the balance between electrostatic and hydrophobic interactions dominating drug partitioning is different in these two systems.
Synthesis and Characterization of a Novel Diels–Alder Adduct of Codeine
Authors: Cunningham Christopher W. , Hom Kellie , Acharya Chayan , Wilks Angela , MacKerell Alexander D. , Coop Andrew
Published: February 2010

The Diels–Alder reaction was applied to 4,5‐epoxymorphinan opioids to generate a novel aromatic cycloadduct at C(7)C(8): Thermolytic cleavage of sultine 8 produced the reactive diene o‐quinodimethane 7 which condensed favorably with codeine (11), but not with codeinone (9) or 14‐hydroxycodeinone (10), producing the desired tetrahydronaphtho adduct 12 with (7R,8R) geometry (Scheme). The configuration of the cycloadduct was determined by 1D‐ and 2D‐NMR experiments. The unanticipated reactivity of these codeine derivatives was investigated by quantum‐mechanical calculations, and it was determined that steric effects of the 6‐keto and 14‐hydroxy group likely precluded condensation by raising the molecular energy of their respective transition states.
Synthesis of Carbocyclic Pyrimidine Nucleosides Using the Mitsunobu Reaction: O2‐ vs. N1‐Alkylation
Authors: Quezada Elías , Viña Dolores , Delogu Giovanna , Borges Fernanda , Santana Lourdes , Uriarte Eugenio
Published: February 2010

The Mitsunobu reaction is an important tool in carbocyclic nucleoside chemistry for the direct coupling of alcohols with heterocyclic bases under mild conditions. Chemical evidences for an unusual competitive O2‐ vs. N1‐alkylation of 3‐substituted pyrimidines is presented.
Nitrogen‐Rich Compounds of the Lanthanoids: Highlights and Summary
Authors: Steinhauser Georg , Giester Gerald , Leopold Nicolae , Wagner Christoph , Villa Mario , Musilek Andreas
Published: February 2010

In this third part of our research on the 5,5′‐azobis[1H‐tetrazol‐1‐ides] (ZT) of the lanthanoids, we present two compounds with La2(ZT)3 moieties with very different coordination modes between the cations and the anions. One La2(ZT)3‐containing compound is interesting, because it contains trimeric La3(ZT)3III cations, which are arranged in a windmill‐like structure. Moreover, the first double salt of a ZT compound, namely the carbonate compound La2(ZT)2(CO3)⋅12 H2O, is presented and discussed. Another highlight of nitrogen chemistry is the first molecular structure of a 5‐azido‐2H‐tetrazole (CHN7) molecule, in the form of the spectacular compound Dy2(ZT)3⋅4 CHN7⋅24 H2O. This is the first known complete molecular structure of an azidotetrazole molecule (the organic molecule with the highest nitrogen‐content: 88.3% N). All compounds have been characterized completely including elemental analyses, vibrational (IR and Raman) spectroscopy, and X‐ray crystal‐structure determination. We summarize our ‘nitrogen‐rich compounds of the lanthanoids’ project and extensively discuss selected literature on this topic and compare previously published results with ours.
Endovenous laser therapy – application studies and latest investigations
Authors: Sroka Ronald , Weick Kathrin , Sadeghi‐Azandaryani Mojtaba , Steckmeier Bernd , Schmedt Claus‐Georg
Published: February 2010

Endovenous laser therapy (ELT) was introduced in clinical practice as a therapy for incompetent veins about ten years ago. One characteristic of ELT is the broad spectrum of different treatment protocols by means of a variety of laser systems as well as manifold application forms and dosimetry concepts are under investigations. Clinical results with effective, relatively pain‐free occlusion of incompetent varicosis veins have been observed, as well as undesired side effects such as ecchymosis, phlebitis and recanalization. In recent years systematic experimental investigations and the analysis of clinical results have increased the understanding of the interrelation between the clinical and physical aspects, followed to a continuous optimization of ELT. The use of IR wavelengths and radial irradiation concepts, together with continuous moving of the optical fiber seem to reduce possible side effects. This way ELT treatment becomes a more standardized effective method for the treatment of varicose veins. In future controlled randomized studies are required to compare optimized ELT treatment with other endoluminal modalities as well as conventional surgery. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Brillouin gain spectrum tailoring technique by using fiber concatenation and strain for fiber devices
Authors: Galindez C. A. , Ullan A. , Madruga F. J. , López‐Higuera J. M.
Published: February 2010

A technique to develop all‐fiber devices based on the customization of Brillouin gain spectrum is proposed in this article. It is based on the proper concatenation and elongation of optical fibers. To check experimentally the proposed technique, an optical device with a “like W” stimulated Brillouin scattering shape was implemented. Our experiment shows a 3‐dB bandwidth of 219 MHz with two reject bands placed at 10.7855 and 10.876 GHz, respectively, from the pump wavelength. Optical devices such as Brillouin amplifiers or Brillouin filters can be developed using the proposed technique. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:787–790, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25033
Dark soliton generation using dual Brillouin fiber laser in a fiber optic ring resonator
Authors: Hanim S. F. , Ali J. , Yupapin P. P.
Published: February 2010

Stable dark soliton pulses have been successfully generated in an erbium doped dispersion compensated fiber (DCF) using an enhanced dual Brillouin fiber laser (DBFL) scheme.Multidark soliton pulses generation in an S‐band erbium doped depressed cladding fiber (DC‐EDF) using a multiwavelength Brillouin fiber laser (MW‐BFL). Configuration has also been successfully demonstrated. The hybrid amplification from the 300 mW power of Raman pump (RP), 7.7 km long DCF, and 30 m DC‐EDF that is being pumped bidirectionally results in a stable multiwavelength Brillouin peaks in the S‐band region. Results obtained shows that the insertion of linear gain medium with bidirectional pumping of the DC‐EDF into the cavity gives significant amplification and promotes the formation of stokes peaks in the S‐band region. The number of Brillouin peaks generated is closely dependent on the DBFL and MW‐BFL configuration, the Brillouin pump (BP) signal wavelength, the BP coupling ratio, and the RP power. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:881–883, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25036
A noncoherent IR‐UWB CMOS receiver for 3–5 GHz application
Authors: Ha Mincheol , Park Youngjin , Lee Jae‐Seung , Eo Yunseong
Published: February 2010

A fully integrated noncoherent IR‐UWB CMOS receiver is implemented using 0.18 μm CMOS technology.To remove the bulky and lossy external balun, the receiver contains single to differential circuit embedded in low‐noise amplifier (LNA) stages. The LNA stage also includes a tunable LC load for band selection. The measured results show that the sensitivity is −78.9 dBm at 1 Mbps in condition of BER of 10–3. The chip size is 2.3 mm × 1.3 mm including pads. The consumed current is 20 mA at 1.8 V supply. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:914–917, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25039
Fast and accurate calculation of transmission coefficients for an EBG microstrip structure
Authors: Ying Huang Shao , Hui Lee Yee
Published: February 2010

In this article, an approach is proposed to provide an accurate and fast calculation on the transmission coefficients of an electromagnetic band‐gap (EBG) structures where patches are periodically inserted into the microstrip line (capacitive loaded EBG microstrip structure). The stopband performance, such as the center frequency, bandwidth, and attenuation, of these EBG structures can be predicted at a high degree of accuracy through the calculation of the transmission coefficient. The dispersion relation of electromagnetic waves in the structure is derived, plotted, and analyzed. The grating nature of the structure is demonstrated. This approach can be applied to periodic microstrip structures of a similar nature to simplify the analysis and design procedures. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:793–797, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25046
UWB portable printed monopole array design for MIMO communications
Authors: Valderas Daniel , Crespo Pedro , Ling Cong
Published: February 2010

Antenna arrays that incorporate MIMO technology for indoor–outdoor network interconnection on the same terminal, i.e., for DCS 1800, PCS 1900, WCDMA, 3G, 802.11a/b/g, Bluetooth®, ZigBee®, WiMAX™, and UWB standards, are proposed. Staircase profile printed circuit antennas, monopoles (PCM), and slots (PCS) with VSWR < 2 bandwidth mainly from 1.12 to 10.1 GHz are previously designed, simulated, constructed, and measured as antenna elements for those arrays. For comparison, prototypes for two‐element PCM and PCS MIMO arrays have been constructed and measured. The choice should be made according to the directivity required by the final application and portable device size. For the worst signal interference case, the operational bandwidth ranges from 1.5 to 9.9 GHz and from 1.7 to 11.4 GHz for the PCM and the PCS MIMO arrays, respectively. VSWR is basically below two, average capacity loss 0.32 bps/Hz with respect to the ideal uncorrelated (2,2) case and envelope correlation lower than 20 dB. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:889–895, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25047
Widely tunable double‐ring resonator add/drop reflection filter based on polymer PLC
Authors: Lee Ho , Lee Youngsik , Kim Gunwoo , Kim Suhyun , Chung Youngchul
Published: February 2010

We demonstrate a widely tunable polymer add/drop reflection filter using double‐ring resonators with slightly different radii. The reflector proposed as an alternative to grating‐based wavelength‐selective reflectors shows a wide tuning range of 42.3 nm using a small amount of current as small as 30 mA. If the proposed reflection filter is hybrid‐integrated with a reflective semiconductor optical amplifier or a superluminescent laser diode, a low‐cost widely tunable laser could be realized. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:852–855, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25048
Low‐voltage/low‐power 7‐GHZtransformer‐coupled current‐reused CMOS QVCO with wide tuning range
Authors: Tseng Yan‐Ru , Huang Tzuen‐Hsi , Wu Shang‐Hsun
Published: February 2010

In this article, we report the design of a transformer‐coupled current‐reused quadrature voltage‐controlled oscillator (QVCO) having low‐voltage operation, low‐power consumption, and a wide tuning range.An improved trifilar transformer that is fabricated by symmetrically interlacing two half circle secondary coils between the turns of the primary coil is proposed to provide a higher magnetic coupling factor. A QVCO integrated with such a trifilar transformer is implemented using 0.18‐μm RF CMOS technology. When the QVCO is operated at a supply voltage of 1V at 7.263 GHz, the measured phase noise is −111.4 dBc/Hz at a 1‐MHz offset. Further, the QVCO core draws only 1.58 mW. The total tuning range is ∼510 MHz over the whole tuning range (from 0 to 1.8 V). The calculated figure of merit is 186.6 dB and the power‐frequency‐tuning‐normalized factor is −9.4 dB. As compared to the reported data in a previous study, a 28.2% reduction in power consumption and a 54.5% increase in tuning range can be achieved. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:797–801, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25058
Complementary predistorter in CMOS differential power amplifier
Authors: Oh Inn‐Yeah , Ra Keuk‐Hwan , Park Chul‐Soon
Published: February 2010

For adaptive improvement of linearity above a 12 dB PAPR for 64QAM WiMAX, a complementary feedback loop in a differential amplifier is adopted as a pre‐distorter that is realized using an NMOS cell operating in the triode region in order to compensate the gm3, the third order transconductance, of the differential amplifier. The power amplifier has been implemented in 0.18 μm CMOS technology, and the chip size is 870 μm × 1050 μm. The proposed PA obtains the 42% efficiency at P1dB while improving the IMD by more than 10 dB above 15 dBm output power levels. It shows a gain of as much as 14.5 dB, and a return loss below −12 dB for 2.3–2.4 GHz operation. Finally, the fabricated PA complies with the spurious emission of WiMAX standards up to 22 dBm. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:833–836, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25062
Design of tri‐band microstrip bandpass filter using folded tri‐section stepped‐impedance resonator
Authors: Liu Haiwen
Published: February 2010

A tri‐band microstrip bandpass filter using folded tri‐section stepped‐impedance resonators is designed, analyzed, and fabricated in this article.Furthermore, the filter's coupling structure analysis and equivalent circuit model are discussed theoretically, and the design methodology of tri‐band filter is explained. Simulated and measured results verify that the central frequencies of the three passbands are located at about 1.6, 2.3, and 4.3 GHz, respectively. Besides, the circuit size of the proposed filter occupies only 26 × 26 mm2 (≈ 0.22λg × 0.22λg). © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:895–898, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25063
CPW‐fed trapezoidal antenna with dual band‐notched characteristic for UWB application
Authors: Xi Juan‐Mei , Liang Chang‐Hong
Published: February 2010

A novel ultra‐wideband (UWB) design of a single‐layer coplanar waveguide‐fed planar monopole antenna with dual band‐notched characteristic is presented. By inserting two opened rectangular loop slots to the ground‐notched trapezoidal patch and adjusting the dimensions of the slots, the proposed antenna, which includes two notched ground planes only 24 mm in width and 31 mm in height, can reach a frequency band‐width, defined by voltage standing wave ratio <2, of 9.4 GHz (from 3 to 12.4 GHz), covering the entire UWB band (3.1–10.6 GHz), and have two frequency notch from 3.55–4.57 GHz and 5.55–6.87 GHz. Good monopole‐like radiation patterns except in the notched frequency band have also been obtained. Details of the proposed antenna design and the simulation results are presented and discussed. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:898–900, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25064
Diffractive optical elements with square concentric rings of equal width
Authors: Alda Javier , Sanchez‐Brea Luis Miguel , Salgado‐Remacha Francisco Javier , Rico‐García José María
Published: February 2010

A diffractive optical element having equal‐width concentric square rings is analyzed in this article. This constant width makes possible its realization using spatial light modulators or square pixels phase screens. It allows a simple analytical treatment, and the element is also simulated using the Rayleigh‐Sommerfeld approach. An experimental verification of its performance has been compared with the simulated results. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:930–934, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25065
Effect of the substrate permittivity on the features of a UWB planar slot antenna
Authors: Barbarino Sebastiano , Consoli Fabrizio
Published: February 2010

The effect of the substrate permittivity on the features of a planar slot antenna for Ultrawideband communications has been investigated here. On this purpose, the same antenna structure has been studied and realized on different substrates. The study involves both simulations and measurements on different realized prototypes. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:935–940, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25066
Dual‐band 3D magnetic EZ antenna
Authors: Lin Chia‐Ching , Ziolkowski Richard W.
Published: February 2010

Several dual‐band three‐dimensional magnetic EZ antenna designs and their simulated performance characteristics are presented. The proposed antennas are formed by integrating multiple capacitively loaded loop elements with a coaxially fed electrically small semicircular loop antenna. They can be designed for a broad range of frequencies by tuning the near field resonant parasitic elements separately. The design details, radiation efficiencies, and fractional bandwidths of these antenna systems for their different dual‐band frequency ranges are reported. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:971–975, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25067
Retracted: Design, simulation, and measurement of metamaterial absorber
Authors: Cheng Yongzhi , Yang Helin
Published: February 2010

The following article from Microwave and Optical Technology Letters, Volume 52, Issue 4, "Design, simulation, and measurement of metamaterial absorber" by Yongzhi Cheng and Helin Yang, published online on February 11, 2010 in Wiley InterScience (www.interscience.wiley.com), has been retracted by the journal Editor‐in‐Chief, Kai Chang, and Wiley Periodicals, Inc. as the Publisher did not have permission from the authors to publish it. The Publisher apologizes for this error.
Broadband low‐profile microstrip antenna design using GPSO based on MOM
Authors: Lin Chen , Zhang Fu‐Sun , Zhao Gang , Zhang Fan , Jiao Yong‐Chang
Published: February 2010

A new evolutionary approach for broadband low‐profile microstrip antenna design is presented. The modified particle swarm optimization algorithm inspired by the wild geese group (Geese‐PSO) and the method of moments (MOM) are combined to optimize the antenna satisfying a certain design criterion. The antenna geometric parameters are extracted to be optimized by Geese‐PSO, and a fitness value is evaluated by MOM simulator to represent the performance of each candidate design. The optimized microstrip antenna with a U‐shaped parasitic element, printed on a thin substrate (thickness of 0.008 λ0), achieves the measured bandwidth of 63 MHz (2.56%), corresponding to the simulated bandwidth of 65 MHz. The agreement between the simulated and measured bandwidths testifies the validity of the GPSO/MOM method. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:975–979, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25069
Small‐size quasi‐fractal patch antenna using the Minkowski curve
Authors: Oliveira E. E. C. , Silva P. H. da F. , Campos A. L. P. S. , d'Assunção A.G.
Published: February 2010

This article shows a new quasi‐fractal microstrip patch antenna using the Minkowski curve at the radiant and nonradiant margin of this device. The structures analyzed were initially designed using the Ansoft Designer™ software that implements the method of moments. Some antenna prototypes were built and measured. The use of the inset‐fed technique enables a good impedance matching, as can be confirmed by the low return loss obtained (<−25 dB) at the resonance frequencies. Antennas designed using the Minkowski curve presented a reduction of up to 42% when compared with a conventional inset‐fed rectangular patch. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:805–809, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25071
Dual‐band and enhanced band FSS characterization using WCIP method
Authors: Titaouine M. , Raveu N. , Gomes Neto A. , Baudrand H.
Published: February 2010

Wave concept iterative procedure (WCIP) is used to analyze dual‐band and enhanced band frequency selective surfaces (FSS). In the metallic U‐shaped simple FSS, a fine‐tune of the two rejected bands is insured by varying independently the length of the two parallel U‐shaped FSS strips. The dual band response can also be obtained from the two‐level rectangular conducting patches FSS. An enhanced rejecting bandwidth is observed for FSS with two square ring printed on each substrate side. The WCIP results are successfully compared with measurements and HFSS results. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:836–839, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25073
Dual‐mode trapezium‐loop microstrip bandpass filter
Authors: Zhang You‐Jun
Published: February 2010

A novel compact and simple microstrip trapezium loop bandpass filter structure using only one resonator is developed in this letter, the inequilaterally structure perturbs the fields of the resonator and excite degenerate modes.Without coupling gaps, the new filter can reduce uncertainty in fabrication. Simulated results agree well with measured results. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:840–841, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25074
Composite right/left‐handed metamaterial transmission lines with unconventional dispersion and applications
Authors: Sisó Gerard , Bonache Jordi , Martín Ferran
Published: February 2010

In this article, novel metamaterial transmission lines exhibiting right‐handed wave propagation at low frequencies and left‐handed wave transmission at high frequencies are presented. The unconventional dispersion characteristics of these composite right/left‐handed transmission lines is obtained by parallel connecting left‐handed and right‐handed unit cells, both implemented by using complementary split‐ring resonators. Thanks to the diplexer action of the structure, either the right‐handed (tuned at the lower frequency band) or the left‐handed (tuned at the upper frequency band) unit cell transmits the injected power, thus achieving the unconventional dispersion of the structure. It is also shown in this article that these artificial lines are of interest for the design of certain microwave components exhibiting dual‐band characteristics. Examples are provided including design and characterization. The measurements are indicative of good device performance at the two operating bands and wide bandwidths. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:904–909, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25077
Tunable terahertz plasmonic lenses based on semiconductor microslits
Authors: Chen Meng‐Ku , Chang Yun‐Ching , Yang Chia‐En , Guo Yaohui , Mazurowski John , Yin Stuart , Ruffin Paul , Brantley Christina , Edwards Eugene , Luo Claire
Published: February 2010

A theoretical investigation of tunable terahertz (THz) plasmonic lenses on the basis of InSb microslits is presented.First, it is demonstrated that the surface plasmon polaritons propagating in an InSb microslit array with variant slit widths would face different phase retardations, which, by design, can produce a focusing wavefront. The extraordinary transmission of THz radiation through the InSb subwavelength slit array is also observed. Second, a method for tuning the focal lengths of InSb plasmonic lenses is proposed. The results in this article provide a potential way to realize a tunable terahertz plasmonic lens with high transmission, which can be applied to the application of rapid 3D z‐scanning based THz imaging and sensing. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:979–981, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25079
Analyzing impedance characteristics of monopole antennas with different chassis widths for dual resonance‐based broadband operation
Authors: Jung Jinwoo , Lee Hyeonjin , Lim Yeongseog
Published: February 2010

Variation of the impedance characteristics between two monopole antennas, according to the width of chassis is analyzed. Dual resonance‐based broadband antennas are proposed on the basis of the analyzed results. The experimental antennas are an inverted L‐shaped monopole antenna and a printed meander line monopole antenna. The dimensions of the derived antennas with a chassis are appropriate for a USB dongle application. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:981–984, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25082
Suspended stripline coupled lines with grounded strips for equalization of inductive and capacitive coupling coefficients
Authors: Gruszczynski Slawomir
Published: February 2010

A suspended stripline coupled‐line structure has been proposed, which allows for achieving equalization of inductive and capacitive coupling coefficients in a wide range of directional couplers' coupling C. Three different variants of the proposed structure have been considered, and the results of numerical calculations using FD technique have been presented, which show the possibility of equalization of inductive and capacitive coupling coefficients. Moreover, graphs showing structural parameters are presented in a wide range of coupling coefficient k. The results of investigations have been confirmed by the measurements of the designed 15‐dB directional coupler. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:874–877, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25085
A rectangular ring backed CPW UWB filter with notched band
Authors: Goyal Shally , Abegaonkar Mahesh P. , Basu Ananjan , Koul Shiban K.
Published: February 2010

A band notched CPW UWB filter backed by rectangular rings is proposed.Initially, cascading of aperture‐backed second‐order microstrip filters is done to achieve the UWB passband. Later, to take advantage of the CPW geometry, the filter is converted to CPW configuration with rings at the back to achieve sharp cutoff characteristics and a notch at 5.1 GHz. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:950–954, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25088
Design of dual‐band quadrifilar spiral antennas for satellite‐mobile handsets
Authors: Abd‐Alhameed R. A. , Zhou D. , See C. H. , Excell P. S. , Abusitta M. M. , Alkhambashi M. S. , McEwan N. J.
Published: February 2010

A novel quadrifilar spiral antenna is proposed for use in personal communications mobile terminals exploiting the “big low earth orbit” (big‐LEO) satellite system (uplink 1.61–1.63 GHz; downlink 2.48–2.5 GHz). Feeding of the antenna from the outer periphery is proposed, to avoid the complexity and space requirements of a centre feed; an externally fed antenna can also be fed either by coaxial cables or stripline. Moreover, the hybrid phasing network and the matching network (if required) can be located outside and possibly printed in the same plane as the antenna structure. Versions of the design were investigated using the method of moments and in hardware realizations. These had a finite ground plane with air dielectric between the spirals and the ground plane. Performance suitable for satellite mobile system applications was demonstrated, including dual‐band matching. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:987–990, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25090
The inhibitory effect of a chewing task on a human jaw reflex
Authors: Maillou Pauline , Cadden Samuel W. , Lobbezoo Frank
Published: February 2010

This study was undertaken to investigate whether an inhibitory jaw reflex could be modulated by experimentally controlled conditions that mimicked symptoms of temporomandibular disorders. Reflecting on previous work, we anticipated that these conditions might suppress the reflex. Electromyographic recordings were made from a masseter muscle in 18 subjects, while electrical stimuli were applied to the upper lip. An inhibitory reflex wave (mean latency 47 ms) was identified and quantified. Immediately following an accelerated chewing task, which in most cases produced muscle fatigue and/or pain, the size of the reflex wave decreased significantly by about 30%. The suppression of inhibitory jaw reflexes by fatigue and pain may result in positive feedback, which may contribute to the symptoms of temporomandibular disorders. Future studies of temporomandibular disorder sufferers will help to determine whether such reflex changes reflect the underlying etiology and/or are a result of the temporomandibular disorder itself. Muscle Nerve, 2010
The β3‐adrenoceptor mediates the inhibitory effects of β‐adrenoceptor agonists via the urothelium in pig bladder dome
Authors: Masunaga Koichi , Chapple Christopher R. , McKay Neil G. , Yoshida Masaki , Sellers Donna J.
Published: February 2010

Aims

Relaxation of detrusor muscle via β‐adrenoceptors may contribute to urine storage during bladder filling. Thus there is increasing interest in β‐adrenoceptor agonists as a potential treatment for detrusor overactivity. The role of the urothelium in bladder responses to β‐adrenoceptor agonists is not yet clear, although we have shown that these agonists have a greater inhibitory effect on detrusor contraction when the urothelium is intact. The aim was to determine which β‐adrenoceptor subtype is involved in this effect.

Methods

Paired strips of pig bladder dome mucosa‐intact and mucosa‐denuded, were mounted in tissue baths. Relaxation responses were obtained to β‐adrenoceptor agonists (isoprenaline, dobutamine, salbutamol or BRL37344) in carbachol pre‐contracted tissues. Inhibitory effects were studied by obtaining concentration‐response curves (CRCs) to carbachol in the presence and absence of β‐adrenoceptor agonists. The inhibitory effects of isoprenaline were also studied following incubation with β‐adrenoceptor antagonists (propranolol, CGP20712, ICI‐118, 551 or SR 59230A; non selected, β1, β2 and β3 selective respectively).

Results

isoprenaline, dobutamine, salbutamol and BRL37344 all relaxed carbachol pre‐contracted tissues and responses were similar in intact and denuded strips. In inhibition experiments, β‐adrenoceptor agonists caused rightward shifts of carbachol CRCs. In intact strips the shift was greater with isoprenaline and BRL37344, but not with dobutamine or salbutamol. This increased shift was still observed in tissues pre‐incubated with propranolo, CGP20712 and ICI‐118, 551, but not with SR 59230A.

Conclusions

β3‐adrenoceptors are involved in mediating inhibitory effects of β‐adrenoceptor agonists on detrusor contractions via the urothelium in pig bladder dome. Neurourol. Urodynam. 29:1320–1325, 2010. © 2010 Wiley‐Liss, Inc.
Synthesis of waterborne nanopolyanilne latexes and application of nanopolyaniline particles in epoxy paint formulation for smart corrosion resistivity of carbon steel
Authors: Jadhav Rajendra S. , Patil Kesharsing J. , Hundiwale Dilip G. , Mahulikar Pramod P.
Published: February 2010

Polyaniline (PANI) latexes were synthesized by emulsion polymerization using dodecyl benzene sulfonic acid (DBSA) and sodium dodecyl sulfate (SDS) as a surfactant. Synthesized PANI–DBSA and PANI–SDS latexes were characterized by IR and UV‐visible spectroscopies, and surface morphology was analyzed by transmission electron microscopy. The PANI–DBSA were found to be nanograin shaped whereas PANI–SDS were as nanofibers. In the second stage rheological properties of waterborne PANI latexes were characterized by viscosity measurement and their dispersion stability in water. The surface morphology of the coating was examined by scanning electron microscope (SEM). The anti‐corrosion performance of uncoated carbon steel, PANI–DBSA and PANI–SDS coated carbon steel was evaluated by tafel slope analysis and immersion test studies of 0.5, 1, and 1.5% PANI/Epoxy coatings were done in 5% NaCl aqueous solution. The results indicated that the nanoPANI in epoxy coating might work as an adhesion promoter and corrosion inhibitor. The waterborne latexes, thus, were found to be highly suitable and avoid the use of organic solvents or strong acids under environmentally benign conditions. Copyright © 2010 John Wiley & Sons, Ltd.
Effect of blending ratio and oligomer structure on the thermal transitions of stereocomplexes consisting of a D‐lactic acid oligomer and poly(L‐lactide)
Authors: Inkinen Saara , Stolt Mikael , Södergård Anders
Published: February 2010

Poly(lactic acid) (PLA) stereocomplexes have high potential as renewable materials for advanced polymer applications, mainly due to their high melting temperature (Tm, typically 230–240°C). The properties of PLA stereocomplexes consisting of linear high molar mass homopolymers have been studied extensively in the past, but the available information about the possibilities to affect the thermal properties of the stereocomplex by varying the structure of the blend components has not been sufficient. Novel stereocomplexes containing linear or star‐shaped D‐lactic acid (D‐LA) oligomers and high molar mass poly(L‐lactide) (L‐PLA) were thus prepared. The Tm and melting enthalpy (ΔHm) of the racemic crystallites were found to depend strongly on both the blending ratio and the arm‐length of the D‐lactic acid oligomer. The preparation method of the oligomers, i.e. step‐growth polymerization or ring‐opening polymerization (ROP), did not affect the Tm or ΔHm of the blends significantly. Slightly higher ΔHm values were, however, obtained, when linear oligomers were used. The results thus indicated that the Tm and ΔHm of PLA stereocomplexes could be optimized, simply by selecting a D‐LA oligomer having a suitable arm‐length and structure as the other blend component. The possibility to adjust the melting behavior of the stereocomplex blend is a significant advantage and could make PLA suitable for a wider range of products used at elevated temperatures. Copyright © 2010 John Wiley & Sons, Ltd.
Poly(3,4‐ethylenedioxythiophene)‐containing semi‐interpenetrating polymer networks: a versatile concept for the design of optical or mechanical electroactive devices
Authors: Vidal Frederic , Plesse Cédric , Aubert Pierre‐Henri , Beouch Layla , Tran‐Van François , Palaprat Guillaume , Verge Pierre , Yammine Paolo , Citerin Johanne , Kheddar Abderrahmane , Sauques Laurent , Chevrot Claude , Teyssié Dominique
Published: February 2010

The synthesis of one‐piece electronic conducting interpenetrating polymer networks is proposed as an alternative to multilayer architectures for the design of electroactive devices. The electronic conducting polymer poly(3,4‐ethylenedioxythiophene) (PEDOT) as active component was symmetrically distributed in a solid polymer electrolyte (SPE) matrix based on poly(ethylene oxide) which was subsequently swollen with either LiClO4 or an ionic liquid. Depending on the composition and the crosslinking density of the SPEs, the ionic conductivities vary between 0.9 × 10−3 and 2.2 × 10−3 S cm−1 at 30 °C. Controlling the PEDOT content from 0.3 to 12 wt% in the material, electrochromic, electroemissive or electromechanical properties are obtained. Typical transmissive and reflective contrast values reach 33 and 27% at 630 and 2500 nm, respectively, for free‐standing films upon application of a 1.2 V bias voltage. Both bending and linear actuating devices were developed as beam‐shaped or hollow fibres. The actuation occurs under low applied voltage up to 4 V and the output force ranges from 50 to 300 mN. In all cases the electroactive properties are stable over 10 000 (electroemissivity) to 3.5 × 106 (actuation) cycles in open air providing an ionic liquid is used as electrolyte. Copyright © 2010 Society of Chemical Industry