bluuebunny/crossref_metadata_2025 huggingface dataset:
PPAR‐β facilitating maturation of hepatic‐like tissue derived from mouse embryonic stem cells accompanied by mitochondriogenesis and membrane potential retention
Authors: Zhu Dan‐yan , Wu Jia‐ying , Li Huan , Yan Jie‐ping , Guo Mei‐yuan , Wo Yan‐bo , Lou Yi‐jia
Published: December 2009

Relatively little is known about mitochondria metabolism in differentiating embryonic stem (ES) cells. Present research focused on several elements of cellular energy metabolism in hepatic‐like tissue derived from mouse ES cells. We demonstrated that mitochondrial location patterns and mitochondrial membrane potential (ΔΨm) existed in subsequent differentiation of the tissue. Mitochondriogenesis appeared at the early stage and kept a normal ΔΨm in differentiated mature hepatocytes. Peroxisome proliferator‐activated receptor‐α (PPAR‐α) expression was transitorily increased at the beginning, and kept a relatively low level later, which accompanied by expression of PPAR‐γ coactivator (PGC)‐1α, a master regulator of mitochondrial biogenesis. PPAR‐β expression showed robust up‐regulation in the late differentiation course. Enhanced co‐expressions of PPAR‐β and albumin with catalysis of UDP‐glucuronosyltransferases (UGTs) were observed at mature stage. While PPAR‐γ expression changed little before and after differentiation. Mitochondriogenesis could be accelerated by PPAR‐α specific agonist WY14643 and abolished by its antagonist GW6471 at the early stage. Neither of them affected mitochondrial ΔΨm and albumin generation in the differentiated hepatocytes. Furthermore, maturation of hepatic‐like tissue and mitochondriogenesis in hepatocyte could be efficiently stimulated by PPAR‐β specific agonist L165041 and abolished by PPAR‐β specific antagonist GSK0660, but not affected by PPAR‐γ specific agonist GW1929. In conclusion, the derived hepatic tissue morphologically possessed cellular energy metabolism features. PPAR‐α seemed only necessary for early mitochondriogenesis, while less important for ΔΨm retention in the mature tissue derived. The stimulation of PPAR‐β but not ‐γ enhanced hepatogenesis, hepatocytes maturation, and mitochondriogenesis. PPAR‐β took an important role in cellular energy metabolism of hepatogenesis. J. Cell. Biochem. 109: 498–508, 2010. © 2009 Wiley‐Liss, Inc.
Mindfulness intervention for child abuse survivors
Authors: Kimbrough Elizabeth , Magyari Trish , Langenberg Patricia , Chesney Margaret , Berman Brian
Published: December 2009

Twenty‐seven adult survivors of childhood sexual abuse participated in a pilot study comprising an 8‐week mindfulness meditation‐based stress reduction (MBSR) program and daily home practice of mindfulness skills. Three refresher classes were provided through final follow‐up at 24 weeks. Assessments of depressive symptoms, post‐traumatic stress disorder (PTSD), anxiety, and mindfulness, were conducted at baseline, 4, 8, and 24 weeks. At 8 weeks, depressive symptoms were reduced by 65%. Statistically significant improvements were observed in all outcomes post‐MBSR, with effect sizes above 1.0. Improvements were largely sustained until 24 weeks. Of three PTSD symptom criteria, symptoms of avoidance/numbing were most greatly reduced. Compliance to class attendance and home practice was high, with the intervention proving safe and acceptable to participants. These results warrant further investigation of the MBSR approach in a randomized, controlled trial in this patient population. © 2009 Wiley Periodicals, Inc. J Clin Psychol 66: 1–18, 2010.
Decomposition of gas‐phase aromatic hydrocarbons by applying an annular‐type reactor coated with sulfur‐doped photocatalyst under visible‐light irradiation
Authors: Jo Wan‐Kuen , Kim Jong‐Tae
Published: December 2009

BACKGROUND: Unlike many water pollution applications, visible‐light‐driven photocatalysis of gas‐phase pollutants has been reported only rarely. The present study was performed to investigate the feasibility of applying S‐doped visible‐light‐induced TiO2 to treat gas‐phase aromatic hydrocarbons, using a continuous air‐flow annular‐type reactor.

RESULTS: The prepared S‐enhanced TiO2 powders, along with a commercially available TiO2 powder (Degussa P‐25), were characterized using diffuse reflectance UV‐VIS‐NIR spectrophotometry, Fourier transform infrared (FTIR) spectrophotometry, X‐ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and thermogravimetry (TG) analyses. A photocatalytic activity test exhibited an increasing trend in degradation reaction rates with increase in flow rate but a decreasing trend in terms of degradation efficiencies. Several experimental conditions induced reasonably high decomposition efficiencies with respect to toluene, ethyl benzene and o,m,p‐xylenes (close to or above 90%), although benzene exhibited a somewhat lower decomposition efficiency.

CONCLUSIONS: The S‐doped TiO2 and undoped P25 TiO2 powders exhibited different catalyst characteristics. The results demonstrate that an annular‐type reactor coated with visible‐light‐activated S‐doped TiO2 can serve as an effective tool to treat gas‐phase aromatic hydrocarbon streams. Copyright © 2009 Society of Chemical Industry
Achromatic number of fragmentable graphs
Authors: Edwards Keith
Published: December 2009

A complete coloring of a simple graph G is a proper vertex coloring such that each pair of colors appears together on at least one edge. The achromatic number ψ(G) is the greatest number of colors in such a coloring. We say a class of graphs is fragmentable if for any positive ε, there is a constant C such that any graph in the class can be broken into pieces of size at most C by removing a proportion at most ε of the vertices. Examples include planar graphs and grids of fixed dimension. Determining the achromatic number of a graph is NP‐complete in general, even for trees, and the achromatic number is known precisely for only very restricted classes of graphs. We extend these classes very considerably, by giving, for graphs in any class which is fragmentable, triangle‐free, and of bounded degree, a necessary and sufficient condition for a sufficiently large graph to have a complete coloring with a given number of colors. For the same classes, this gives a tight lower bound for the achromatic number of sufficiently large graphs, and shows that the achromatic number can be determined in polynomial time. As examples, we give exact values of the achromatic number for several graph families. © 2009 Wiley Periodicals, Inc. J Graph Theory 65:94–114, 2010
Radiosynthesis of N‐[4‐(4‐fluorobenzyl)piperidin‐1‐yl]‐N′‐(2‐[11C]oxo‐1,3‐dihydrobenzimidazol‐5‐yl)oxamide, a NR2B‐selective NMDA receptor antagonist
Authors: Labas Romain , Sobrio Franck , Bramoullé Yann , Hérard Anne‐Sophie , Guillermier Martine , Hantraye Philippe , Dollé Frédéric , Barré Louisa
Published: December 2009

In order to perform in vivo imaging of the NR2B NMDA receptor system by positron emission tomography, a NR2B selective NMDA receptor antagonist has been labelled with carbon‐11 (half‐life: 20 min). N‐[4‐(4‐fluorobenzyl)piperidin‐1‐yl]‐N′‐(2‐oxo‐1,3‐dihydrobenzimidazol‐5‐yl)oxamide has been described demonstrating high affinity and selectivity for the NR2B receptors (IC50 of 5 nM in [3H]Ro‐25,6981 binding assay). The labelling precursor and the reference compound were synthesized by coupling the 4‐(4‐fluorobenzyl)piperidine with the corresponding oxalamic acid. The reaction of [11C]phosgene with phenylenediamine precursor led the formation of the [11C]benzimidazolone ring present on the ligand. The labelling occurred in THF or acetonitrile and the decay corrected radiochemical yield was 30–40% from the produced [11C]methane. HPLC purification and formulation led to 2.6–3.7 GBq (70–100 mCi) of radioligand within 30–35 min. The specific radioactivity was 72–127 GBq/µmol (2–3.4 Ci/µmol) at the end of synthesis. Copyright © 2009 John Wiley & Sons, Ltd.
Neuroprotective effects of PDGF against oxidative stress and the signaling pathway involved
Authors: Zheng Lianshun , Ishii Yoko , Tokunaga Ayano , Hamashima Takeru , Shen Jie , Zhao Qing‐Li , Ishizawa Shin , Fujimori Toshihiko , Nabeshima Yo‐ichi , Mori Hisashi , Kondo Takashi , Sasahara Masakiyo
Published: December 2009

The neuroprotective effects of platelet‐derived growth factor (PDGF) and the major signaling pathways involved in these were examined using primary cultured mouse cortical neurons subjected to H2O2‐induced oxidative stress. The specific function of the PDGF β‐receptor (PDGFR‐β) was examined by the selective deletion of the corresponding gene using the Cre‐loxP system in vitro. In wild‐type neurons, PDGF‐BB enhanced the survival of these neurons and suppressed H2O2‐induced caspase‐3 activation. The prosurvival effect of PDGF‐AA was less than that of PDGF‐BB. PDGF‐BB highly activated Akt, extracellular signal‐regulated kinase (ERK), c‐jun amino‐terminal kinase (JNK) and p38. PDGF‐AA activated these molecules at lesser extent than PDGF‐BB. In particular, PDGF‐AA induced activation of Akt was at very low level. The neuroprotective effects of PDGF‐BB were antagonized by inhibitors of phosphatidylinositol 3‐kinase (PI3‐K), mitogen‐activated protein kinase kinase (MEK), JNK and p38. The PDGFR‐β‐depleted neurons showed increased vulnerability to oxidative stress, and less responsiveness to PDGF‐BB‐induced cytoprotection and signal activation, in which Akt activation was most strongly suppressed. After all, these results demonstrated the neuroprotective effects of PDGF and the signaling pathways involved against oxidative stress. The effects of PDGF‐BB were more potent than those of PDGF‐AA. This might be due to the activation and additive effects of two PDGFRs after PDGF‐BB stimulation. Furthermore, the PI3‐K/Akt pathway that was deduced to be preferentially activated by PDGFR‐β may explain the potent effects of PDGF‐BB. © 2009 Wiley‐Liss, Inc.
Enhanced neurogenesis in the olfactory bulb in adult mice after injury induced by acute treatment with trimethyltin
Authors: Yoneyama Masanori , Kawada Koichi , Ogita Kiyokazu
Published: December 2009

In adults, the subventricular zone is known to contain undifferentiated neural progenitor cells that proliferate and generate the olfactory bulb (OB) interneurons throughout life. We earlier showed that trimethyltin (TMT) causes neuronal damage in the granular cell layer of the OB in adult mice. In the current study, we examined neurogenesis in the OB in adult mice after injury induced by acute treatment with TMT. On day 2 post‐TMT treatment, enhanced incorporation of 5‐bromo‐2′‐deoxyuridine (BrdU) was seen in the granular cell layer of the OB. Many of the BrdU‐labeled cells were undifferentiated cells on day 2 post‐treatment. On day 30 post‐TMT treatment, BrdU‐labeled neuronal cells were dramatically increased in number in the granular cell layer of the OB. However, TMT treatment was ineffective in affecting the migration of BrdU‐labeled cells from the subventricular zone to the OB. The results of a neurosphere assay revealed that the number of neurospheres derived from the OB was significantly increased on day 2 post‐TMT treatment. The neurosphere‐forming neural progenitor cells derived from the OB of TMT‐treated animals were capable of differentiating into neuronal cells as well as into astrocytes. Taken together, our data suggest that the OB has the ability to undergo enhanced neurogenesis following TMT‐induced neuronal injury in adult mice. © 2009 Wiley‐Liss, Inc.
Sulforaphane protects immature hippocampal neurons against death caused by exposure to hemin or to oxygen and glucose deprivation
Authors: Soane Lucian , Li Dai Wei , Fiskum Gary , Bambrick Linda L.
Published: December 2009

Oxidative stress is a mediator of cell death following cerebral ischemia/reperfusion and heme toxicity, which can be an important pathogenic factor in acute brain injury. Induced expression of phase II detoxification enzymes through activation of the antioxidant response element (ARE)/Nrf2 pathway has emerged as a promising approach for neuroprotection. Little is known, however, about the neuroprotective potential of this strategy against injury in immature brain cells. In this study, we tested the hypothesis that sulforaphane (SFP), a naturally occurring isothiocyanate that is also a known activator of the ARE/Nrf2 antioxidant pathway, can protect immature neurons from oxidative stress‐induced death. The hypothesis was tested with primary mouse hippocampal neurons exposed to either O2 and glucose deprivation (OGD) or hemin. Treatment of immature neurons with SFP immediately after the OGD during reoxygenation was effective in protecting immature neurons from delayed cell death. Exposure of immature hippocampal neurons to hemin induced significant cell death, and both pre‐ and cotreatment with SFP were remarkably effective in blocking cytotoxicity. RT‐PCR analysis indicated that several Nrf2‐dependent cytoprotective genes, including NAD(P)H quinone oxidoreductase 1 (NQO1), heme oxygenase 1 (HO1), and glutamate‐cysteine ligase modifier subunit (GCLM), which is involved in glutathione biosynthesis, were up‐regulated following SFP treatment both in control neurons and following exposure to OGD and hemin. These results indicate that SFP activates the ARE/Nrf2 pathway of antioxidant defense and protects immature neurons from death caused by stress paradigms relevant to those associated with ischemic and traumatic injury to the immature brain. © 2009 Wiley‐Liss, Inc.
Marker compounds for the determination of retention factors in EKC
Authors: Wiedmer Susanne K. , Lokajová Jana , Riekkola Marja‐Liisa
Published: December 2009

EKC and its sub‐techniques, such as MEKC and microemulsion EKC, have attracted wide interest in recent years. Investigations on this topic have covered several analytical applications, but attention has also been paid more and more to basic studies. This review provides an overview of the different approaches to calculating retention factors, which express the ratio of the amount of sample component in the pseudostationary and mobile phases. Special attention is given to the selection of markers for the determination of the electrophoretic mobility or migration time of a marker describing the behavior of the pseudostationary phase in EKC. Introduction of a hydrophobic marker is by far the most common approach, but the use of a homologous series of compounds is also quite popular. In addition, other possible approaches found in the literature will be described.
Combined antegrade and retrograde esophageal dilation for head and neck cancer‐related complete esophageal stenosis
Authors: Goguen Laura A. , Norris Charles M. , Jaklitsch Michael T. , Sullivan Christopher A. , Posner Marshall R. , Haddad Robert I. , Tishler Roy B. , Burke Elaine , Annino Donald J.
Published: December 2009

Objectives/Hypothesis:

Assess the safety and efficacy of combined antegrade and retrograde esophageal dilation (CARD) for complete esophageal stenosis following head and neck cancer (HNC) treatment. Review HNC dysphagia management.

Study Design:

Retrospective review of all patients undergoing CARD following HNC treatment between May 2001 and September 2008.

Methods:

Forty‐five patients were identified for review. Parameters assessed included: ability to obtain intraoperative esophageal patency, complications, number of dilations required, diet, and gastric tube (GT) status. Factors associated with dilation failure were analyzed.

Results:

Intraoperative esophageal patency was obtained in 91% of patients. Median number of all dilations per patient was three. Median number of CARDs per patient was one. Resumption of oral intake occurred in 36/45 (80%). Diet results included: regular or soft diet 32/45 (71%), GT removal 27/45 (60%), and GT dependence with nothing by mouth 9/45 (20%). Laryngeal and pharyngeal stenosis, radionecrosis, tracheotomy dependence, and elongated stenosis were associated with dilation failure. Complications occurred in 18/63 (29%) CARD procedures: eight pneumomediastinum, seven GT site problems, two esophageal perforations, and one pharyngeal infection. All complications resolved spontaneously or with minimal interventions.

Conclusions:

CARD was safe and effective. Intraoperative patency was achieved in 91% of patients. Eighty percent resumed oral intake. The majority of patients had their GTs removed and resumed a soft or regular diet. Dilation failure was associated with laryngeal, pharyngeal, and excessively long esophageal stenosis, often resulting from radionecrosis. Complications were minor. CARD should be considered before relegating patients with complete esophageal stenosis to chronic GT dependence or subjecting them to laryngopharyngo esophagectomy. Laryngoscope, 2010
Hereditary hemorrhagic telangiectasia/avastin
Authors: Davidson Terence M. , Olitsky Scott E. , Wei Julie L.
Published: December 2009

This is the first scientific report of hereditary hemorrhagic telangiectasia (HHT) epistaxis treatment by intranasal spraying of the vascular endothelial growth factor (VEGF) inhibitor bevacizumab (Avastin). Epistaxis in patients with HHT is a morbid, mortal condition that is difficult and unpleasant to manage. Nasal telangiectasia growth is modulated by VEGF, which is elevated in HHT patients. Bevacizumab is a VEGF inhibitor that diminishes epistaxis when administered intravenously or injected locally, or as reported here when sprayed topically onto the nasal mucosa. Laryngoscope, 2010
Preparation and Unique pH‐Responsive Properties of Novel Biodegradable Nanocapsules Composed of Poly(γ‐glutamic acid) and Chitosan as Weak Polyelectrolytes
Authors: Imoto Takayuki , Kida Toshiyuki , Matsusaki Michiya , Akashi Mitsuru
Published: December 2009

Novel biodegradable hollow nanocapsules composed of two kinds of weak polyelecrolytes, CT and γ‐PGA, were successfully prepared by the deposition of their LbL‐assembled films onto silica particles and the subsequent removal of the silica. These CT‐γ‐PGA hollow nanocapsules showed unique size increases at pH = 1.0, due to the swelling of capsule membranes induced by electrostatic repulsions between ammonium groups of CT components. On the other hand, no significant changes in the capsule size were observed at pH = 4.0, 7.0, and 10. By using the CT‐γ‐PGA nanocapsules, the release of encapsulated substances in response to acidic pH values was accomplished.

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Copolymer of Fluorene and Triphenylamine Moieties: Direct and Post‐Functionalization Strategy, Structural Characterization, and Chemosensoring Behavior
Authors: Yang Rong , Wu Weibing , Wang Wenyu , Li Zhen , Qin Jingui
Published: December 2009

To prepare a copolymer of fluorene and triphenylamine bearing imidazole groups in the side chain, two synthetic approaches have been designed: the direct copolymerization of the corresponding monomers, and the post‐functionalization of a precursor polymer. Unexpectedly, the direct copolymeriztion strategy was better. The chemosensing behavior of P2 was carefully studied, the fluorescence of which could be quenched by Cu2+ ions at concentrations as low as 8 × 10−6 mol · L−1 in dilute solutions. By utilizing the much higher stability constant of the complex of CN− and Cu2+, the quenched fluorescence of the solution of P2 by Cu2+ ions could be recovered upon the addition of a trace amount of CN− anions, with a detection limit as low as 1.8 × 10−5 mol · L−1 (0.47 ppm), making P2 a new sensitive cyanide probe.

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Lamellar Nanoconfinements Effects in Discotic Liquid Crystalline Block Copolymers
Authors: Stillings Christopher , Pettau Robin , Wendorff Joachim H. , Schmidt Hans‐Werner , Kreger Klaus
Published: December 2009

We have evaluated the effect of slit‐like nanoconfinements imposed on columnar discotic phases within a discotic block copolymer displaying a lamellar microphase. Findings are that the columns are oriented uniformly along the lamellar normal within the plane of thin films, that a rectangular rather than a hexagonal columnar phase is formed within the discotic regions, that the thermodynamic stability of the columnar phase is strongly reduced relative to the low molar mass model compounds and finally, that the isotropic phase can be unusually strongly supercooled with respect to the columnar phase formation. Slit‐like nanoconfinements allow thus to induce novel types of the intrinsic order and columnar orientations.

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Synthesis of Co3O4/Poly(N‐vinylcarbazole) Core/Shell Composite With Enhanced Optical Property
Authors: Maity Arjun , Ray Suprakas Sinha
Published: December 2009

Co3O4/poly(N‐vinylcarbazole) (PNVC) composite with enhanced optical property was synthesized via a simple in situ bulk polymerization of NVC monomers in the presence of Co3O4 nanoparticles at an elevated temperature. High‐resolution electron microscopic observations showed that the Co3O4 nanoparticles were coated with uniform nanolayer shells of PNVC. Fourier‐transform infrared (FT‐IR) spectroscopy revealed the presence of strong interactions between the PNVC polymer chains with the Co3O4 surface in the Co3O4/PNVC composite. Raman spectroscopic results supported conclusions based on electron microscopy and FT‐IR spectra. The uniform nanolayer coating of PNVC decreases the inherent bulk conductivity of Co3O4, however, significantly increases the fluorescence property of Co3O4 nanoparticles.

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Public commitment as a motivator for weight loss
Authors: Nyer Prashanth U. , Dellande Stephanie
Published: December 2009

Many long‐term services, e.g., weight‐loss programs, require that customers comply with instructions, provide the inputs, and thus co‐create a major portion of the service. This article investigates the role of public commitment in influencing motivation and behavior in a weight‐loss setting. The role of susceptibility to normative influence (SNI) is also examined. The publicness with which a commitment to weight loss is made has a significant and favorable impact on long‐term weight‐loss compliance behavior. Short‐ and long‐term public commitment resulted in higher levels of weight‐loss motivation and higher levels of weight loss. Weight‐loss motivation partly mediates the effect of public commitment on weight loss, while SNI moderates the effect of public commitment on weight loss. © 2009 Wiley Periodicals, Inc.
Moderators of the negativity effect: Commitment, identification, and consumer sensitivity to corporate social performance
Authors: Liu Tsung‐Chi , Wang Chung‐Yu , Wu Li‐Wei
Published: December 2009

Numerous studies have identified constructs such as commitment and brand familiarity as moderators of negativity effects. However, boundary conditions for this moderation have yet to be identified within a retailing context. This study tries to rectify this gap in the literature. This study finds that three factors (commitment, consumer–company identification, and consumer sensitivity to corporate social performance) moderate attitude change toward a retailer following exposure to moderately negative (vs. positive) publicity. However, given extremely negative information, the buffering effects of the moderating factors disappear, and attitude changes are significant for all consumers. © 2009 Wiley Periodicals, Inc.
Design of Organoiron Macromolecules Based on Upper Rim Functionalized Calix[4]arenes
Authors: Abd‐El‐Aziz Alaa S. , Shipman Patrick O. , Shipley Paul R.
Published: December 2009

The versatility of cationic cyclopentadienyliron complexes is demonstrated for the generation of calix[4]arene‐based dendrimers and polymers. Dendrimers were prepared from a branched organoiron calix[4]arene through subsequent reactions of azo dyes and organoiron complexes. The resulting azo dye‐containing metallocalix[4]arenes were soluble in polar organic solvents and displayed λmax ranging between 430 and 456 nm. Upon addition of various acids, the λmax shifted to higher wavelengths (513–535 nm). In the solid state and in solution, the azo dye‐containing metallocalix[4]arenes reversibly changed colour in the presence of acid and base, indicating their potential use as acid sensors. Cyclic voltammetric studies showed that the iron centres of the metallocalix[4]arenes were reversibly reduced at E1/2 = −1.49 V. When non‐branching organoiron‐based calix[4]arene were reacted with dithiols, polymers containing calix[4]arenes either in their side chains or main chains were obtained. The polymers possessed weight average molecular weights between 35 000 and 53 000. The polymers were determined to be thermally stable with backbone decomposition occurring above 500 °C.

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A novel notch waveguide filter
Authors: Prikolotin Sergey A. , Kirilenko Anatoliy A.
Published: December 2009

The simple configurations of realistic rejection units placed in a rectangular waveguide are suggested. They are thin stepped conductors connecting the opposite waveguide walls and forming a kind of thin two‐aperture irises easily placed, for example, between waveguide flanges. A rejection phenomenon is based on the interference of the eigenoscillation fields of the iris with two L‐shaped apertures. The rejection frequency and quality factor are controlled over a wide range by the placement and the height of the conductor step. The situation when a stepped perfect conductor provides the resonance of a nearly zero bandwidth is revealed. In other words, such a nontrivial 3D waveguide unit loaded with above‐cutoff waveguides is able to support an eigen oscillation without any radiation loss. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 416–420, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24892
Determination of resonant frequency of slot‐loaded rectangular microstrip patch antennas
Authors: Neog Dipak Kr. , Devi Reeta
Published: December 2009

A generalized method is presented to determine the resonant frequency of slot‐loaded rectangular microstrip patch antenna by equating its area to an equivalent area of a rectangular microstrip patch antenna. The computed results are in good agreement with the reported simulated and measured results. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 445–448, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24901
Rectangle waveguide to substrate integrated waveguide transition and power divider
Authors: Li Chao , Wu Di , Seo Kazuyuki
Published: December 2009

A novel Ku‐band transition and power divider between rectangle waveguide (RWG) and substrate integrated waveguide (SIW) is proposed. This transition and power divider is realized by a radiating metal patch located on the backside of a middle dielectric substrate and a coupling aperture etched on the SIW's ground plane. The transition and power divider is studied both simulatively and experimentally. As reported, low insertion loss of not higher than 0.6 dB and good return loss of −15 dB may be achieved at the frequency range of 12.1–12.8 GHz. The method to increase the bandwidth is investigated. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 375–378, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24902
High eye‐quality improvement by a single‐SOA regenerative wavelength converter
Authors: Ribeiro Napoleão S. , Gallep Cristiano M. , Conforti Evandro
Published: December 2009

A simple all‐optical cross‐gain modulation (XGM) wavelength conversion scheme based on a single semiconductor optical amplifier with higher regeneration capabilities is presented. A proof of concept was performed at data rates from 0.6 to 13.5 Gbps for NRZ streams using the KyaTera/FAPESP buried fiber optical testbed. Good results were obtained for large lambda‐detuning (>10 nm), including conversion to the same wavelength. The best experiments achieved an improvement in the quality factor (Q‐factor) over 4 units with input signals deteriorated by the standard fiber dispersion, with an extinction ratio penalty of 1.5 dB. In addition, the converter presented a small dependence with the relative optical input signal polarization (around 1dB). © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 441–445, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24906
Scattering of a special class of isorefractive spherical objects with spherical anisotropy
Authors: Xue Jing , Lee Hyue
Published: December 2009

The isorefractive scattering by spherically anisotropic spheres is established for the plane‐wave incidence. The effects of the anisotropy ratio in the scattering cross‐sections are studied, and physical insights to particular phenomena are provided. The equivalence in the far‐field scattering is also revealed for both isorefractive and spherically uniaixal anisotropic spheres. The peculiarities in the scattering for both small and large anisotropic spheres and the dependence on spherical anisotropy are presented and discussed. The method developed here thus possesses higher degree of generality and applicability, which can study scattering problems of anisotropic bodies as well as model some physical problems. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 334–338, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24911
Three antenna array design for buried object detection
Authors: Ghosh Debalina , Sarkar Tapan K.
Published: December 2009

An impulse radiating GPR system is designed with resistively loaded antennas, which are placed in an array configuration to cancel ground bounce and antenna coupling effects. The target response is isolated through deconvolution by the conjugate gradient method. By applying the matrix pencil method to the late time response the natural resonant frequencies of the target are extracted for identification. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 338–343, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24912
Double‐printed rectangular patch dipole antenna with band‐notched function for UWB communications
Authors: Xiao Jin‐Xiang , Wang Mei‐Fang , Li Guo‐Jian
Published: December 2009

A novel double‐printed rectangular patch dipole antenna with a band‐notched function suitable for UWB application is presented and investigated in this article. The band‐notched characteristic is achieved by connecting L‐shaped strips to the antenna rather than inserting slot to the antenna. The measured results show that the frequency band of VSWR < 2 covers 3.1 to 10.6 GHz UWB band, whereas the notched‐frequency range is 5.05–6.1 GHz which covers 5GHz WLAN band of 5.15–5.825 GHz. Transfer function and time domain characteristics are also studied in this article. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 269–272, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24921
Nonlinear behavioral of GaN Doherty power amplifiers using neural modeling
Authors: Liu Haiwen
Published: December 2009

A radial‐basis function neural network (RBFNN) approach is proposed for predicting the nonlinear behaviors of gallium nitride (GaN) Doherty amplifier. Sampled input and output data from a designed GaN Doherty amplifier were used to train and test the proposed RBFNN model. Comparison of amplitude modulation to amplitude modulation (AM/AM), amplitude modulation to phase modulation (AM/PM), gain, power added efficiency (PAE) and output power (Pout) curves among the RBFNN method, circuit simulation and measurement are given. The results indicate that the proposed RBFNN model can reproduce the nonlinear characteristics of the designed GaN Doherty amplifier accurately. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 307–309, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24924
Experimental and numerical investigation of a magnetic resonator antenna based on the M‐type hexaferrite (BaxSr1−xFe12O19)
Authors: Pereira F. M. M. , Sohn R. S. T. M. , Rodrigues H. O. , Júnior G. F. M. P. , Theophilo K. R. B. , Rocha M. J. S. , Silva M. A. S. , Sombra A. S. B.
Published: December 2009

In this work is reported an experimental and numerical investigation of magnetic resonator antennas (MRA) of magnetic the alloy BaxSr1−xFe12O19 obtained in a new procedure in the solid‐state method. The experimental and theoretical characteristics of the antenna like return loss, bandwidth, input impedance, and radiation patterns are in good agreement. Numerical validation is done, taking into account the air gaps between the dielectric resonator and the metallic conductors. Frequency response bandwidth in the range of 9–10% was obtained for frequency operation around 4 GHz. The alloys BaxSr1−xFe12O19 showed a dielectric constant around 8, with loss in the range 10−2–10−3. The temperature coefficient of resonant frequency (τf) was also measured for magnetic alloys BaxSr1−xFe12O19. The values obtained were in the range of 44.90–87.83 ppm/°C. These results obtained confirm the potential use of those materials for small dielectric MRA. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 452–458, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24931
A novel reduced λ/4 resonant monopole with associated extra inductance
Authors: Tirado‐Mendez J. A. , Jardon‐Aguilar H. , Flores‐Leal R. , Reyes‐Ayala M.
Published: December 2009

In this article, a novel technique is employed to reduce the dimensions of a λ/4 resonant monopole. The procedure considers the antenna covered by a cylindrical conductor and short‐circuited at the top of the resonator, separated by a dielectric similar to a coaxial line. With this technique, the length of the monopole can be reduced up to40% without modifying, significantly, the parameters of the antenna. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 276–280, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24933
Advantage of a hybrid MoM scheme with approximate Green function to model integrated glass antennas
Authors: Bogdanov Faik G. , Karkashadze David D. , Jobava Roman G. , Gheonjian Anna L. , Yavolovskaya Ekaterina A. , Bondarenko Natalia G.
Published: December 2009

A new hybrid MoM scheme with approximate Green function of antenna elements, printed‐on or embedded into the glass, is described. This scheme is used to simulate scattering characteristics of integrated glass antenna models. Comparison with measurement data and with previous modeling techniques for different measurement setups is performed. An advantage of the proposed modeling technique over previous techniques is demonstrated. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 351–354, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24936
Bandwidth enhancement of slot‐fed dielectric resonator antenna
Authors: Madhuri R. G. , Hadalgi P. M. , Mallikarjun S. L. , Malipatil S. A.
Published: December 2009

Novel slot‐fed dielectric resonator antenna is studied experimentally. The antenna is comprised of a rectangular dielectric resonator and a mictrostrip fed coupling slot. The multiband resonances of the two radiators i.e., slot and dielectric resonator are combined to extend the antenna bandwidth. Dielectric resonator of three different thicknesses is studied, providing a bandwidth of 49.25%. The radiation patterns are measured and are presented. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 316–318, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24937
Design of DC to 10‐GHz broadband CMOS transmit/receive switch circuits
Authors: Lin Yih‐Hsia , Chu Chun‐Hsueh , Gong Jeng
Published: December 2009

This article presents the design of CMOS transmit/receive (T/R) switch circuits for ultra‐wideband applications. Techniques such as RF floated body to extend the bandwidth and decrease the insertion loss, and stacking architecture to enhance the power handling capability are used for the design of T/R switch circuits on a standard 0.18‐μm triple‐well process. The measurement of the T/R switch circuits demonstrates the effectiveness of the methods presented in this article. Two types of T/R switch circuits are designed and presented in this article. The T/R switch with non‐stacking architecture achieves an insertion loss less than 1.2 dB and an input 1‐dB compression point (IP1dB) of 24 dBm from DC to 10 GHz for. In addition, the T/R switch with stacking architecture exhibits a higher IP1dB of 27 dBm and an insertion loss less than 1.69 dB from DC to 10 GHz. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 322–326, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24948
A wideband digital predistortion for highly linear and efficient GaN HEMT Doherty power amplifier
Authors: Lee Mun‐Woo , Lee Yong‐Sub , Kam Sang‐Ho , Jeong Yoon‐Ha
Published: December 2009

In this article, we propose the wideband digital predistortion (WDPD) for a highly linear and efficient GaN HEMT Doherty power amplifier (DPA). The WDPD is composed of the memory less DPD and the memory system, which compensates for the memory effects to achieve a highly linear wideband performance. The 11th‐memoryless polynomial characterizes the behavioral model of the DPA. The AM/AM and AM/PM lookup tables and the coefficients of the memory system are determined by the Recursive Least Square algorithm. For a 2‐FA WCDMA signal with 10 MHz carrier spacing at 2.14 GHz, the adjacent channel leakage ratio at ±10 MHz offset are improved over −50 dBc without the efficiency degradation at an output power of 36 dBm. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 484–487, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24951
Micro‐coaxial Ka‐band Gysel power dividers
Authors: Saito Yuya , Fontaine Daniel , Rollin Jean‐Marc , Filipovic Dejan S.
Published: December 2009

Monolithic, 450‐μm tall, rectangular coaxial Gysel divider is presented in this article. The divider is fabricated by a surface micromachining process with six sequentially deposited copper layers. Athree‐port, resistor‐less divider has overall loss of 0.6 dB at 30 GHz, input port reflection coefficient better than −10 dB, and output amplitude and phase misbalances of ±0.18 dB and ±1.8°, respectively, throughout Ka‐band. The device is designed in a way that permits straightforward realization of a Gysel divider with integrated resistors. Electromagnetic and electrothermal analyses and design of the divider are conducted, and good agreement with measurements is obtained. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 474–478, 2010; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/mop.24956
A partition of unity‐based multiscale approach for modelling fracture in piezoelectric ceramics
Authors: Verhoosel Clemens V. , Remmers Joris J. C. , Gutiérrez Miguel A.
Published: December 2009

The development of models for a priori assessment of the reliability of micro electromechanical systems is of crucial importance for the further development of such devices. In this contribution a partition of unity‐based cohesive zone finite element model is employed to mimic crack nucleation and propagation in a piezoelectric continuum. A multiscale framework to appropriately represent the influence of the microstructure on the response of a miniaturized component is proposed. It is illustrated that using the proposed multiscale method a representative volume element exists. Numerical simulations are performed to demonstrate the constitutive homogenization framework. Copyright © 2009 John Wiley & Sons, Ltd.
On the C1 continuous discretization of non‐linear gradient elasticity: A comparison of NEM and FEM based on Bernstein–Bézier patches
Authors: Fischer P. , Mergheim J. , Steinmann P.
Published: December 2009

In gradient elasticity, the appearance of strain gradients in the free energy density leads to the need of C1 continuous discretization methods. In the present work, the performances of C1 finite elements and the C1 Natural Element Method (NEM) are compared. The triangular Argyris and Hsieh–Clough–Tocher finite elements are reparametrized in terms of the Bernstein polynomials. The quadrilateral Bogner–Fox–Schmidt element is used in an isoparametric framework, for which a preprocessing algorithm is presented. Additionally, the C1‐NEM is applied to non‐linear gradient elasticity. Several numerical examples are analyzed to compare the convergence behavior of the different methods. It will be illustrated that the isoparametric elements and the NEM show a significantly better performance than the triangular elements. Copyright © 2009 John Wiley & Sons, Ltd.
Study of cure kinetics of epoxy/DDS/nanosized (SiO2/TiO2) system by dynamic differential scanning calorimetry
Authors: Safarpour M. A. , Omrani A. , Afsar S. , Zare‐Hossein‐Abadi D.
Published: December 2009

In this study the curing kinetics of epoxy based on the diglycidyl ether of bisphenol A (DGEBA), 4,4′‐diaminodiphenyl sulfone (DDS) as a hardener, and SiO2/TiO2 (70:30) as a nanofiller was investigated by nonisothermal differential scanning calorimetry (DSC). The effects of different weight contents of SiO2/TiO2 nanoparticles were studied using DSC in Dynamic Mode and the best value of the nanofiller was found to be 5 phr (parts per hundred). Dynamic measurements were used to obtain the total heat of reaction of the epoxy system as well as its activation energy (Ea) based on the isoconversional methods of Kissinger and Ozawa. The process revealed a dependence of the activation energy on conversion (α). The morphology of the cured system was investigated by scanning electron microscopy (SEM). It showed a strong cross‐linking between the resin and hardner and a relatively better dispersion of surface modified filler nanoparticles. Copyright © 2009 John Wiley & Sons, Ltd.
Biodegradable poly(p‐dioxanone) reinforced and toughened by organo‐modified vermiculite
Authors: Qiu Zhi‐Cheng , Zhang Jing‐Jing , Zhou Yan , Song Bo‐Ya , Chang Jing‐Jing , Yang Ke‐Ke , Wang Yu‐Zhong
Published: December 2009

Poly(p‐dioxanone) (PPDO)/vermiculite (VMT) nanocomposites with exfoliated structure were prepared successfully by in situ intercalative polymerization of p‐dioxanone (PDO) in the presence of organo‐modified vermiculite (OVMT) with the aid of ultrasonic action. The nano‐structure of the nanocomposites was established using X‐ray diffraction (XRD) analysis and transmission electron microscopy (TEM) observations. The investigation of crystallization behavior by differential scanning calorimetry (DSC) and polarized optical microscopy (POM) proved that exfoliated OVMT platelets acted as a template for spherulite growth. The thermal stability of nanocomposites was enhanced than that of pure PPDO. Dynamic mechanical analysis (DMA) indicated nanoscale OVMT platelets restricted the motion of PPDO segments, which benefitted the increase of storage and loss modulus. The tensile properties showed that nanocomposites were reinforced and toughened significantly by the addition of nanoscale OVMT platelets. Copyright © 2009 John Wiley & Sons, Ltd.
Studies on swelling kinetics for HPC/PAN thermo‐sensitive blending films
Authors: Gong Guo‐li , Li Hui , Li Xiao‐yan
Published: December 2009

A series of thermo‐sensitive blending films was prepared from hydroxypropylcellulose (HPC) and polyacrylonitrile (PAN). The effects of materials ratio, pH value, and temperature on the swelling velocity of these blending films were studied. At temperatures above the lower critical solution temperature (LCST), different results are found after dipping blend film samples in acid or alkaline solutions, respectively. At a pH value of 1.4, the swelling velocity of HPC/PAN blended films increased with the HPC content. The films' swelling was mainly controlled by polymer chain relaxation. For a pH value of 7.4 the mechanism responsible for the swelling is the water molecules' diffusion. The swelling velocity was also affected by temperature and pH. Copyright © 2009 John Wiley & Sons, Ltd.
Successful mobilization, harvest and transplant of peripheral blood stem cells using AMD3100 and G‐CSF following high dose craniospinal irradiation for medulloblastoma in a young child
Authors: Toledano Helen , Yahel Anat , Cohen Ian J. , Yaniv Isaac , Stein Jerry
Published: December 2009

Contemporary protocols for the treatment of malignant brain tumors such as medulloblastoma (MB) in children, often involve craniospinal irradiation (CSI) at diagnosis followed by serial courses of high dose chemotherapy and autologous hematopoietic stem cell support. Patients often require several pheresis procedures in order to collect sufficient stem cells for this type of treatment, particularly if they have already had CSI. We describe the successful mobilization, collection and subsequent transplant of a 7‐year‐old female with medulloblastoma after recent CSI using granulocyte colony stimulating factor (G‐CSF) and the CXCR4 antagonist AMD3100 after a failed previous mobilization attempt using G‐CSF alone. Pediatr Blood Cancer 2010;54:613–615. © 2009 Wiley‐Liss, Inc.
Poly[(N‐isopropylacrylamide)‐co‐(itaconic acid)] hydrogels with poly(ethylene glycol)
Authors: Kalagasidis Krušić Melina , Veličković Sava J , Griffiths Peter C , Filipović Jovanka
Published: December 2009

The aim of the work reported here was to investigate temperature‐ and pH‐sensitive hydrogels of N‐isopropylacrylamide (NIPAM) and itaconic acid (IA) and their semi‐interpenetrating polymer networks (semi‐IPNs) with varying contents of poly(ethylene glycol) (PEG). The stimuli responsiveness, swelling behaviour and mechanical properties of the hydrogels and semi‐IPNs were studied in order to investigate the effect of various amounts of PEG. Pulsed‐gradient spin‐echo NMR experiments were carried out to investigate the diffusion process. The pH sensitivity increased with an increasing amount of PEG in the semi‐IPNs, while the overall rate of water uptake was diffusion‐controlled (n < 0.5). For certain PEG contents (5 and 10 wt%), the semi‐IPNs exhibited better mechanical properties than the poly(NIPAM‐co‐IA) copolymer. The calculated values of the self‐diffusion coefficients of water indicated facilitated diffusion of water through the system with increased amounts of PEG, while the self‐diffusion coefficients of a model compound, metoprolol tartrate, showed no significant dependence on the amount of PEG. According to the results obtained and compared to results reported in the literature, the investigated semi‐IPNs may have potential applications in the controlled release of macromolecular active agents such as proteins and peptides. Copyright © 2009 Society of Chemical Industry
Biodegradable stimuli‐responsive hydrogels based on amphiphilic polyaspartamides with tertiary amine pendent groups
Authors: Moon Jong Rok , Kim Ji‐Heung
Published: December 2009

Novel thermo‐ and pH‐responsive hydrogels based on amphiphilic polyaspartamides possessing a lower critical solution temperature (LCST) and a volume‐phase transition were prepared and characterized. The polyaspartamide derivatives were synthesized from polysuccinimide, which is the polycondensate of L‐aspartic acid monomer, through successive ring‐opening reactions using hydrophobic 2‐diisopropylaminoethylamine and hydrophilic ethanolamine. The amphiphilic copolymer was then crosslinked with hexamethylene diisocyanate to afford the corresponding gel. The LCST of the copolymer in an aqueous solution was varied by changing both the graft composition and pH of the medium. The crosslinked gels showed stimuli‐responsive behavior, with their degree of swelling and porous structure morphology changing with temperature and pH. In addition, hydrolytic degradation depending on the crosslinking density of the hydrogel was examined. Copyright © 2009 Society of Chemical Industry