bluuebunny/crossref_metadata_2025_split huggingface dataset:
Frequency and pattern reconfigurable Yagi patch antenna
Authors: Yang Xue‐Song , Wang Bing‐Zhong , Xiao Shaoqiu , Fung Man Kim 
Published: January 2008

AbstractThis work describes the use of switched slits and slots to reconfigure the operating frequency and the radiation pattern of a Yagi patch antenna. The Yagi patch antenna is fabricated on the top side of a grounded substrate and is fed by a coaxial probe. By using switches to reconfigure the silts etched on the driven patch, the antenna can operate at two frequencies of 8.175 and 9.31 GHz. By changing the states of the slots etched on different parasitic element patches, directions of the radiation pattern can be changed. Thus, a design that is reconfigurable in both frequency and radiation pattern is accomplished. As a proof of concept, five models are fabricated and tested. Three of them operate at the higher frequency and two of them at the lower one. The main beams of these models point to different directions in the E‐plane. Simulated and measured results are given and they are in good agreement. The antenna can be used in radar, satellite communications, etc. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 716–719, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23214
GPS antenna design with slotted ground plane
Authors: Sim Chow‐Yen‐Desmond , Han Tuan‐Yung 
Published: January 2008

AbstractA single layer, single‐feed circularly polarized (CP) microstrip antenna designed with 2 pairs of slot embedded on its ground plane for global positioning system (GPS) is proposed. The experimental results shown that by simply tuning the length of the slotted pair, two orthogonal near‐degenerate resonant modes for CP radiation can be excited. By comparing the proposed antenna to a reference antenna of similar sizes with two pairs of slit embedded on the radiating square patch; the proposed antenna demonstrated enhancement in gain, bandwidth, and radiation efficiency. Furthermore, in comparison to other CP antennas with slotted ground plane design, it demonstrated an excellent F/B ratio and wide 3 dB beamwidth. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 818–821, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23215
Optical current sensor based on metal coated Hi‐Bi fiber loop mirror
Authors: Marques B. V. , Frazão O. , Mendonça S. , Perez J. , Marques M. B. , Santos S. F. , Baptista J. M. 
Published: January 2008

AbstractAn optical current sensor based on a metal coated Hi‐Bi fiber loop mirror is reported. This current sensor quantifies the current through the measurement of the temperature which varies accordingly with the magnitude of the electrical current. The temperature change is analyzed through the variation of the wavelength shift of a fringe minimum of a Hi‐Bi fiber loop mirror. The minimum current detection was found to be approximately 10 A. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 780–782, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23217
Surface and proper leaky‐modes in a lossless grounded pseudochiral omega slab
Authors: Matos Sérgio A. , Paiva Carlos R. , Barbosa Afonso M. 
Published: January 2008

AbstractSurface and proper leaky modes guided by a grounded pseudochiral omega slab are studied. A new physical result is found: proper leaky modes may occur in a lossless grounded pseudochiral omega slab even when all medium parameters are positive. A correlation between polaritons at interfaces and leaky modes in slab waveguides is established. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 814–818, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23220
Mesenchymal stem cell‐based angiopoietin‐1 gene therapy for acute lung injury induced by lipopolysaccharide in mice
Authors: Xu J , Qu J , Cao L , Sai Y , Chen C , He L , Yu L 
Published: January 2008

AbstractBone marrow‐derived mesenchymal stem cells (MSCs) can serve as a vehicle for gene therapy. Angiopoietin‐1 (Ang1) is a critical factor for endothelial survival and vascular stabilization via the inhibition of endothelial permeability and leukocyte–endothelium interactions. We hypothesized that MSC‐based Ang1 gene therapy might be a potential therapeutic approach for lipopolysaccharide (LPS)‐induced lung injury. MSCs were isolated from 6 week‐old inbred male mice and transduced with the Ang1 gene, using a lentivirus vector. The MSCs showed no significant phenotypic changes after transduction. In the in vivo mouse model, the LPS‐induced lung injury was markedly alleviated in the group treated with MSCs carrying Ang1 (MSCs–Ang1), compared with groups treated with MSCs or Ang1 alone. The expression of Ang1 protein in the recipient lungs was increased after MSCs–Ang1 administration. The histopathological and biochemical indices of LPS‐induced lung injury were improved after MSCs‐based Ang1 gene treatment. MSCs–Ang1 administration also reduced pulmonary vascular endothelial permeability and the recruitment of inflammatory cells into the lung. Cells of MSC origin could be detected in the recipient lungs for 2 weeks after injection with MSCs. These results suggest that MSCs and Ang1 have a synergistic role in the treatment of LPS‐induced lung injury. MSC‐based Ang1 gene therapy may be developed as a potential novel strategy for the treatment of acute lung injury. Copyright © 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Preparation and characterization of polypropylene/solid‐state organomodified montmorillonite nanocomposites
Authors: Yu‐hai Sun , Yuan‐Fang Luo , De‐Min Jia 
Published: January 2008

AbstractA novel organomodified montmorillonite prepared by solid‐state method and its nanocomposites with polypropylene were studied. The interaction between modifying agent and montmorillonite was investigated by X‐ray diffraction (XRD) analysis, contact angle determination, and Fourier‐transform infrared spectroscopy. The results showed that the modifying agent behaves as an effective intercalating agent, enlarging the interlayer spacing of montmorillonite and making montmorillonite more hydrophobic. Polypropylene/solid‐state organomodified montmorillonite composites were prepared by melt‐mixing method. The dispersion of the silicates was investigated by XRD analysis and transmission electron microscopy. It was found that the nanocomposites are formed with solid‐state organomodified montmorillonite and polypropylene. The thermogravimetric analysis and differential scanning calorimetry results showed that the organoclay could enhance the thermal stability and decrease the relative crystallinity of polypropylene. Mechanical and rheological tests indicated that the organoclay improves the mechanical properties but has no obvious effect on rheological properties of polypropylene. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers
Real‐time measurement of flow front kinematics using quantitative visualization in injection molding process
Authors: Fathi S. , Behravesh A.H. 
Published: January 2008

AbstractThis article presents an experimental method for measuring the kinematics of the melt flow front, during the filling stage of the plastic injection molding process. The three main steps were: (i) visualization of the flow front advancement, (ii) image processing of the recorded results, and (iii) calculation of the flow front kinematics. The designed visual mold was capable of monitoring the flow advancement in two different cases: (i) a simple (nonconstrained) plate and (ii) a constrained plate (with an obstacle pin). Variations in instant flow rate, melt front area (MFA), and average melt front velocity (MFV) during filling stage were measured as a function of time. The applied technique could clearly show the flow behavior from which the flow front parameters could be extracted. A particle tracking velocimetry (PTV) method was also applied to study the orientation behavior of the advancing melt front. The time history of the particle's velocity components at the flow front could be easily extracted using the method. POLYM. ENG SCI., 2008. © 2008 Society of Plastics Engineers
Why 3‐D? Gel‐based microarrays in proteomics
Authors: Rubina Alla Yu. , Kolchinsky Alexander , Makarov Alexander A. , Zasedatelev Alexander S. 
Published: January 2008

AbstractGel‐based microarrays (biochips) consisting of nanoliter and sub‐nanoliter gel drops on hydrophobic substrate are a versatile technology platform for immobilization of proteins and other biopolymers. Biochips provide a highly hydrophilic environment, which stabilizes immobilized molecules and facilitates their interactions with analytes. The probes are immobilized simultaneously with gel polymerization, evenly distributed throughout individual elements, and are easily accessible because of large pores. Each element is an isolated nanotube. Applications of biochips in the studies of protein interactions with other proteins, nucleic acids, and glycans are described. In particular, biochips are compatible with MALDI‐MS. Biochip‐based assay of prostate‐specific antigen became the first protein microarray approved for clinical use by a national regulatory agency. In this review, 3‐D immobilization is compared with mainstream technologies based on surface immobilization.
Informatics for peptide retention properties in proteomic LC‐MS
Authors: Shinoda Kosaku , Sugimoto Masahiro , Tomita Masaru , Ishihama Yasushi 
Published: January 2008

AbstractRetention times in HPLC yield valuable information for the identification of various analytes and the prediction of peptide retention is useful for the identification of peptides/proteins in LC‐MS‐based proteomics. Informatics methods such as artificial neural networks and support vector machines capable of solving nonlinear problems made possible the accurate modeling of quantitative structure‐retention relationships of peptides (including large polymers) up to 5 kDa to which classical linear models cannot be applied, as well as the proteome‐wide prediction of peptide retention. Proteome‐wide retention prediction and accurate mass‐information facilitate the identification of peptides in complex proteomic samples. In this review, we address recent developments in solid informatics methods and their application to peptide‐retention properties in ‘bottom‐up’ shotgun proteomics. We also describe future prospects for the standardization and application of retention times.
Feasibility of the spontaneous gas‐phase proton transfer equilibria between neutral Brønsted acids and Brønsted bases
Authors: Burk Peeter , Koppel Ivar , Trummal Aleksander , Koppel Ilmar A. 
Published: January 2008

AbstractThe computational investigation of interactions of different acid–base pairs regarding the nature and extent of spontaneous proton transfer was carried out at B3LYP/6‐311 + G** level. The selected acid–base pairs include the interactions of strong base (K2O) with acids of different strength (HClO4, HCl, and HF), and strong acid (HClO4) with bases ranging from K2O (GB = 322.8 kcal/mol) to H2O (GB = 157.6 kcal/mol). It was shown that spontaneus, unassisted proton transfer can take place in the gas‐phase reactions of strong neutral Brønsted acids and bases. The reaction might be barrierless as in case of interactions between strong acids and bases, for example perchloric acid and alkali metal oxides or potassium oxide and halogen hydrides, or involve the encounter complex (hydrogen bonded acid–base cluster), which is separated from ion‐pair by the transition state. Copyright © 2008 John Wiley & Sons, Ltd.
The synthesis and characterization of new thermoplastic poly(thiourethane‐urethane)s
Authors: Kultys Anna , Rogulska Magdalena , Pikus Stanisław 
Published: January 2008

AbstractNew thermoplastic segmented poly(thiourethane‐urethane)s (SPTUUs) were prepared by a one‐step melt polymerization from 20 to 80 mol % poly(tetramethylene oxide) of $\overline M _{\rm n}$ = 1000 or poly(hexamethylene carbonate) diol (PHCD) of $\overline M _{\rm n}$ = 860 as soft segments, hexamethylene diisocyanate (HDI) and bis[4‐(mercaptomethyl)phenyl]methanone (BMMPM) as a new dithiol chain extender at the NCO/(OH + SH) molar ratio of 1 in the presence of dibutyltin dilaurate as a catalyst. The structures of the SPTUUs were examined by FTIR, X‐ray diffraction analysis, and scanning electron microscopy. The SPTUUs were also characterized by physicochemical, thermal, and tensile properties as well as Shore A/D hardness. The SPTUUs with the PHCD soft segments showed better tensile properties than those with the PTMO soft segments. A nonsegmented polythiourethane based on BMMPM and HDI is also described. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1770–1782, 2008
Inhaled furosemide in hospitalized infants with viral bronchiolitis: A randomized, double‐blind, placebo‐controlled pilot study
Authors: Bar Amir , Srugo Isaac , Amirav Israel , Tzverling Chana , Naftali Gabi , Kugelman Amir 
Published: January 2008

AbstractObjectiveTo evaluate the short and long‐term clinical effects and the treatment‐feasibility of inhaled‐furosemide (IF) as compared with placebo via hood in hospitalized infants with viral‐bronchiolitis (VB).Study‐DesignA randomized, double‐blind, placebo‐controlled pilot‐study was performed in previously healthy infants (0–12 months). Enrolled infants were randomized to receive either IF (2 mg/kg), or placebo nebulized by hood three times daily throughout the hospitalization. Clinical assessment (respiratory distress assessment instrument [RDAI]) was performed before, 30 and 60 min after the 1st daily inhalation. The short‐term effects were evaluated by the RDAI, respiratory assessment change score (RACS) and oxygen requirement and the long‐term effects by time to be weaned off oxygen, time to full enteral feeding, length of stay, and “ready to discharge” time.ResultsBoth groups (16 infants each) had comparable characteristics at study entry. Mean (±SD) age was 72 ± 43 days, and 29/32 infants were RSV positive. Oxygen requirement (FiO2) decreased significantly at 30 min post‐inhalation (30 ± 9.2% to 26 ± 7.1%, P < 0.05) only in the IF group. RACSs and long‐term effects of both groups were comparable. Analysis of IF particles generated by the hood‐nebulizer demonstrated that 36% and 49% of the particles were <3 and 5 µm, respectively. No side effects were observed during IF treatment.ConclusionBased on our pilot study, IF has no significant clinical effects in hospitalized infants with VB. IF via hood seems to be feasible and safe. Pediatr Pulmonol. 2008; 43:261–267. © 2008 Wiley‐Liss, Inc.
Effect of zinc supplementation on respiratory tract infections in children with cystic fibrosis
Authors: Abdulhamid I. , Beck F.W.J. , Millard S. , Chen X. , Prasad A. 
Published: January 2008

AbstractZinc (Zn) has significant anti‐oxidant and anti‐inflammatory activity. Zn deficiency can occur in subsets of patients with cystic fibrosis (CF) especially those with malabsorption and impaired growth. Although supplemental Zn has significantly reduced infections in various disorders, its efficacy has not been thoroughly investigated in CF. We performed a double blind placebo controlled pilot study to investigate the effect of daily 30 mg elemental Zn for 1 year on the rate of respiratory tract infections (RTIs), use of antibiotics and plasma cytokines in 26 children with CF (ages 7–18 years). Plasma Zn, Cu, inflammatory cytokines and ex vivo generation of IL‐2 were measured at baseline and at the end of the study. The number of days of oral antibiotics was lower in Zn treated patients compared to placebo (P = 0.05). However, compared to placebo, the effect of Zn was greater in patients who exhibited low plasma Zn at baseline (P = 0.02) than those who had plasma Zn levels identical to normal subjects (P = 0.55). Zn supplementation was marginally effective in reducing percentage increase in plasma IL‐6 and IL‐8 while increasing the percentage change in ex vivo generation of IL‐2 in isolated mononuclear cell. In conclusion, oral intake of 30 mg/day of Zn reduced the number of days of oral antibiotics used to treat RTIs in children with CF. A higher daily Zn dose may be needed to decrease RTIs and modify immune responses. Pediatr Pulmonol. 2008; 43:281–287. © 2008 Wiley‐Liss, Inc.
Quantum field theories coupled to supergravity
Authors: Große J. 
Published: January 2008

AbstractThis article is devoted to the investigation of the interplay of supersymmetric Yang–Mills theories (SYM) and supergravity (SUGRA). The topic is studied from two points of view: Firstly from the point of view of AdS/CFT correspondence, which realises the coupling of four dimensional superconformal 𝒩 = 4 SYM theory and ten dimensional type IIB SUGRA in a holographic way. In order to arrive at theories that resemble quantum chromodynamics (QCD) more closely, fundamental fields are introduced using probe D7‐branes and non‐trivial background configuration are considered. In particular supergravity solutions that are only asymptotically anti‐de Sitter and break supersymmetry are used. This allows the description of spontaneous chiral symmetry breaking. The meson spectrum is calculated and the existence of an associated Goldstone mode is demonstrated. Moreover it is shown that highly radially excited mesons are not degenerate. Additionally instanton configurations on the D7‐branes are investigated, which lead to a holographic description of the dual field theory's Higgs branch. Finally a holographic description of heavy‐light mesons is developed, which are mesons consisting of quarks with a large mass difference, such that a treatment of B mesons can be achieved The second approach is the technique of so‐called space‐time dependent couplings (also known as “local couplings”), where coupling constants are promoted to external sources. This allows to explore the conformal anomaly of quantum field theories coupled to a classical gravity background. The technique is extended to the superfield description of 𝒩 = 1 supergravity, a complete basis for the anomaly is given and the consistency conditions that arise from a cohomological treatment are calculated. Possible implications for an extension of Zamolodchikov's c‐theorem to four dimensional supersymmetric quantum field theories are discussed.
Comprehensive analysis of the helix‐X‐helix motif in soluble proteins
Authors: Deville Julie , Rey Julien , Chabbert Marie 
Published: January 2008

Abstractα‐Helices are the most common secondary structures found in globular proteins. In this report, we analyze the stereochemical and sequence properties of helix‐X‐helix (HXH) motifs in which two α‐helices are linked by a single residue, in search of characteristic structures and sequence signals. The analysis is carried out on a database of 837 nonredundant HXH motifs. The kinks are characterized by the bend angle between the axes of the N‐terminal and C‐terminal helices and the wobble angle corresponding to the rotation of C‐terminal helix axis on the plane perpendicular to the N‐terminal one. The phi‐psi dihedral angles of the linker residue are clustered in six distinct areas of the Ramachandran plot: two areas are located in the additional allowed α region (α1 and α2), two areas are in the additional allowed β region (β1 and β2) and two areas have positive phi values (αL and βM). Each phi/psi region corresponds to characteristic bend and wobble angles and amino acid distributions. Bend angles can vary from 0° to 160°. Most wobble angles correspond to a counter‐clockwise rotation of the C‐terminal helix. Proline residues are rigorously excluded from the linker position X but have a high propensity at position X+1 of the β1 and β2 motifs (12 and 7, respectively) and at position X+3 of the α1 motifs (9). Glycine linkers are located either in the αL region (20%) or in the βM region (80%). This latter conformation is characterized by a marked bend angle (124° ± 18°) and a clockwise wobble. Among other amino acids, Asn is remarkable for its high propensity (>3) at the linker position of the α2, β1, and β2 motifs. Stabilization of HXH motifs by H‐bonds between polar side chains of the linker and polar groups of the backbone is determined. A method based on position‐specific scoring matrices is developed for conformational prediction. The accuracy of the predictions reaches 80% when the method is applied to proline‐induced kinks or to kinks with bend angles in the 50°–100° range. Proteins 2008. © 2008 Wiley‐Liss, Inc.
Rational design of peptides active against the gram positive bacteria Staphylococcus aureus
Authors: Landon Céline , Barbault Florent , Legrain Michèle , Guenneugues Marc , Vovelle Françoise 
Published: January 2008

AbstractIn an attempt to increase the antimicrobial activity of the insect defensin from Anopheles gambiae, which is active against Staphylococcus aureus at low concentration, hybrid defensins were designed by combining conserved sequence regions and variable regions of insect defensins. Their activity against S. aureus strains sensitive and resistant to conventional antibiotics was evaluated, and the toxicity of the most active molecules was tested. The three‐dimensional structure of Anopheles gambiae defensin and five hybrids were determined by NMR and molecular modelling. This strategy led to the design of two chimeric defensins with increased activity compared with the native molecule, but one of them appears to be toxic to mice at a rather low concentration. The structure of the CSαβ motif, which is a characteristic of insect defensin, is sensitive to sequence modifications, in particular in the N‐terminal loop. The existence of the CSαβ is most probably a prerequisite for the stability and the activity of the molecule, but is not sufficient by itself since the hybrid displaying the best defined structure is not active against the tested strains. The analysis of the structure, in relation with the activity and the toxicity data, underlines the importance of turns and of the N‐terminal loop. Residues located in the turns contributing to the preservation of positive electrostatic areas at the surface of the molecules seem particularly important for the activity of the molecule, while residues involved in the N‐terminal loop are both involved in the modulation of the activity and the toxicity of the molecule. Proteins 2008. © 2008 Wiley‐Liss, Inc.
Mechanism of inhibition of wt‐dihydrofolate reductase from E. coli by tea epigallocatechin‐gallate
Authors: Spina Michele , Cuccioloni Massimiliano , Mozzicafreddo Matteo , Montecchia Francesca , Pucciarelli Stefania , Eleuteri Anna Maria , Fioretti Evandro , Angeletti Mauro 
Published: January 2008

AbstractDihydrofolate reductase (DHFR) is a ubiquitous enzyme involved in major biological process, including DNA synthesis and cancer inhibition, and its modulation is the object of extensive structural, kinetic, and pharmacological studies. In particular, earlier studies showed that green tea catechins are powerful inhibitors of bovine liver and chicken liver DHFR. In this article, we report the results of inhibition kinetics for the enzyme from another source (DHFR from E. coli) exerted by (−)‐epigallocatechingallate (EGCG). Using different analytical techniques, we reported that EGCG acts as a bisubstrate inhibitor on the bacterial DHFR. Moreover, the combined approach of biosensor, kinetic, and molecular modelling analysis disclosed the ability of EGCG to bind to the enzyme both on substrate (DHF) and cofactor (NADPH) site. Collectively, our data have confirmed the selectivity of antifolate compounds with respect to the different source of enzyme (bacterial or mammalian DHFR) and the possible role of tea catechins as chemopreventive agents. Proteins 2008. © 2008 Wiley‐Liss, Inc.