bluuebunny/crossref_metadata_2025 huggingface dataset:
Osteoblastic response to collagen scaffolds varied in freezing temperature and glutaraldehyde crosslinking
Authors: Chen Dai‐Chian , Lai Yu‐Lin , Lee Shyh‐Yuan , Hung Shan‐Ling , Chen Hen‐Li
Published: September 2006

Collagen sponges are widely used scaffolds in bone engineering. To form bone, the osteoblastic cells undergo proliferation, differentiation, and mineralization stages in the scaffold. Crosslinking and freezing temperature are two important variables in fabricating collagen sponges. The purpose of this study was to examine the osteoblastic responses to collagen sponges prepared with or without glutaraldehyde crosslinking at different freezing temperatures (−20°C or −80°C). MC3T3‐E1 osteoblastic cells were cultured in differently prepared sponges. Osteoblastic responses examined included cell numbers, osteocalcin expression, and calcium deposition. Cell numbers were measured by DNA content. Osteocalcin expression was determined by RT‐PCR and real‐time RT‐PCR. Calcium deposition was assayed by ortho‐cresophthalein complexone method and von Kossa stain. The osteoblastic cells grown in all collagen sponges did not show apparent signs of cytotoxicity. Collagen sponges differed in freezing temperatures resulted in similar osteoblastic responses. Glutaraldehyde‐crosslinked sponges demonstrated less cell‐mediated contraction and more cell numbers at day 7 (p < 0.005). However, they showed lower osteocalcin expression at day 7 (p < 0.05) and less calcium deposition at day 21 (p < 0.001). In summary, different freezing temperatures played a minor role in osteoblastic responses. Glutaraldehyde crosslinking process, though improved the dimensional stability of collagen sponges, might compromise the osteoblastic differentiation and mineralization. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2007
Study on the ability of 1,2,3,4‐tetrahydropapaveroline to cause oxidative stress: Mechanisms and potential implications in relation to parkinson's disease
Authors: Soto‐Otero Ramón , Sanmartín‐Suárez Carolina , Sánchez‐Iglesias Sofía , Hermida‐Ameijeiras Álvaro , Sánchez‐Sellero Inés , Méndez‐Álvarez Estefanía
Published: September 2006

Tetrahydropapaveroline (THP) is a compound derived from dopamine monoamine oxidase–mediated metabolism, particularly present in the brain of parkinsonian patients receiving L‐dopa therapy, and is capable of causing dopaminergic neurodegeneration. The aim of this work was to evaluate the potential of THP to cause oxidative stress on mitochondrial preparations and to gain insight into the molecular mechanisms responsible for its neurotoxicity. Our data show that THP autoxidation occurs with a continuous generation of hydroxyl radicals (•OH) and without the involvement of the Fenton reaction. The presence of ascorbate enhances this process by establishing a redox cycle, which regenerates THP from its quinolic forms. It has been shown that the production of •OH is not affected by the presence of either ferrous or ferric iron. Although THP does not affect lipid peroxidation, it is capable of reducing the high levels of thiobarbituric acid–reactive substances obtained in the presence of ascorbate and/or iron. However, THP autoxidation in the presence of ascorbate causes both an increase in protein carbonyl content and a reduction in protein‐free thiol content. THP also increases protein carbonyl content when the autoxidation occurs in the presence of iron. The remarkable role played by ascorbate in the production of oxidative stress by THP autoxidation is of particular interest. © 2006 Wiley Periodicals, Inc. J Biochem Mol Toxicol 20:209–220, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20138
Metabolic effects of carbenoxolone in rat liver
Authors: Pivato Leandro Silva , Constantin Rodrigo Polimeni , Ishii‐Iwamoto Emy L. , Kelmer‐Bracht Ana Maria , Yamamoto Nair Seiko , Constantin Jorgete , Bracht Adelar
Published: September 2006

The action of carbenoxolone on hepatic energy metabolism was investigated in the perfused rat liver and isolated mitochondria. In perfused livers, carbenoxolone (200–300 μM) increased oxygen consumption, glucose production and glycolysis from endogenous glycogen. Gluconeogenesis from lactate or fructose, an energy‐dependent process, was inhibited. This effect was already evident at a concentration of 25 μM. The cellular ATP levels and the adenine nucleotide content were decreased by carbenoxolone, whereas the AMP levels were increased. In isolated mitochondria, carbenoxolone stimulated state IV respiration and decreased the respiratory coefficient with the substrates β‐hydroxybutyrate and succinate. The ATPase of intact mitochondria was stimulated, the ATPase of uncoupled mitochondria was inhibited, and the ATPase of disrupted mitochondria was not altered by carbenoxolone. These results indicate that carbenoxolone acts as an uncoupler of oxidative phosphorylation and, possibly, as an inhibitor of the ATP/ADP exchange system. The inhibitory action of carbenoxolone on mitochondrial energy metabolism could be contributing to induce the mitochondrial permeability transition (MPT), a key phenomenon in apoptosis. The results of the present study can explain, partly at least, the in vivo hepatotoxic actions of carbenoxolone that were found in a previous clinical evaluation. © 2006 Wiley Periodicals, Inc. J Biochem Mol Toxicol 20:230–240, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20139
Heterogeneity of the coumarin anticoagulant targeted vitamin K epoxide reduction system. Study of kinetic parameters in susceptible and resistant mice (Mus musculus domesticus)
Authors: Lasseur Romain , Grandemange Agnès , Longin‐Sauvageon Christiane , Berny Philippe , Benoit Etienne
Published: September 2006

Vitamin K epoxide reductase (VKOR) activity in liver microsomes from a susceptible and a genetically warfarin‐resistant strain of mice (Mus Musculus domesticus) was analyzed to determine the mechanism of resistance to this 4‐hydroxycoumarin derivative. Kinetic parameters for VKOR were calculated for each strain by incubating liver microsomes with vitamin K epoxide ± warfarin. In susceptible mice, an Eadie–Hofstee plot of the data was not linear and suggested the involvement of at least two different components. Apparent kinetic parameters were obtained by nonlinear regression using a Michaelis‐‐Menten model, which takes into account two enzymatic components. Component A presents a high Km and a high Vm, and as a consequence only an enzymatic efficiency Vm/Km was obtained (0.0024 mL/min/mg). Estimated warfarin Ki was 0.17 μM. Component B presented an apparent Km of 12.73 μM, an apparent Vm of 0.32 nmol/min/mg, and an apparent Ki for warfarin of 6.0 μM. In resistant mice, the enzymatic efficiency corresponding to component A was highly decreased (0.0003–0.00066 mL/min/mg) while the Ki for warfarin was not modified. The apparent Vm of component B was poorly modified between susceptible and resistant mice. The apparent Km of component B observed in resistant mice was similar to the Km observed in susceptible mice. These modifications of the catalytic properties are associated with a single nucleotide polymorphism (T175G) in the VKOR‐C1 gene, which corresponds to a Trp59Gly mutation in the protein. © 2006 Wiley Periodicals, Inc. J Biochem Mol Toxicol 20:221–229, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20144
Effect of Cymbopogon citratus L. essential oil on growth and morphogenesis of Saccharomyces cerevisiae ML2‐strain
Authors: Helal G. A. , Sarhan M. M. , Abu Shahla A. N. K. , Abou El‐Khair E. K.
Published: September 2006

The growth of Saccharomyces cerevisiae was completely inhibited using 2.0 µl/ml or 4.0 µl/ml of Cymbopogon citratus essential oil applied by fumigation or contact method in Sabouraud's broth medium, respectively. This oil was found also to be fungicidal at the same concentrations. The sublethal doses 1.0 and 3.0 µl/ml inhibited about 98% of yeast growth after 24 hr of incubation as compared with the control. Microscopic observations using Light Microscope (LM), Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) showed morphogenic and ultrastructure changes in the fumigated cells with 1.0 µl/ml of the oil. These changes including decrease in cell size, depressions on the surface of the cells, alteration in cell wall thickness and disruption of plasma membrane. Moreover, Ca+2, K+ and Mg+2 leakages increased from the fumigated cells and its total lipid content decreased. Also, the fatty acid composition was altered with decrease in the amount of saturated fatty acids and increase in the amount of unsaturated fatty acids. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of coating the wells of a polystyrene microtiter plate with xanthorrhizol on the biofilm formation of Streptococcus mutans
Authors: Rukayadi Yaya , Hwang Jae‐Kwan
Published: September 2006

Colonization on the surface of tooth by Streptococcus mutans is an important step in the initiation of dental plaque. Polystyrene microtiter plates have been employed to study bacterial colonization and biofilm formation of periodontal bacteria. The objective of this work was to evaluate the effect of coating the wells of a polystyrene microtiter plate with xanthorrhizol isolated from java turmeric (Curcuma xanthorrhiza Roxb.) on Strep. mutans biofilm formation. Our studies demonstrated that coating of a polystyrene microtiter plate with 5 µg/ml of xanthorrhizol resulted in significant (up to 60%) reduction of adherent cells compared to that of cells in uncoated wells. This result suggests that xanthorrhizol displays potent activity in preventing Strep. mutans biofilm formation. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Acinetobacter bioreporter assessing heavy metals toxicity
Authors: Abd‐El‐Haleem Desouky , Zaki Sahar , Abulhamd Ashraf , Elbery Hassan , Abu‐Elreesh Gadallah
Published: September 2006

This work was conducted to employ a whole cell‐based biosensor to monitor toxicity of heavy metals in water and wastewater. An isolate of industrial wastewater bacterium, Acinetobacter sp. DF4, was genetically modified with lux reporter gene to create a novel bioluminescent bacterial strain, designated as DF4/PUTK2. This bioreporter can investigate the toxicity through light inhibition due to cell death or metabolic burden and the specific stress effects of the tested soluble materials simultaneously. The use of Acinetobacter DF4/PUTK2 as a bioluminescent reporter for heavy metal toxicity testing and for the application of wastewater treatment influent toxicity screening is presented in this study. Among eight heavy metals tested, the bioluminescence of DF4/PUTK2 was most sensitive to Zn, Cd, Fe, Co, Cr followed by Cu in order of decreasing sensitivity. The same pattern of sensitivity was observed when several contaminated water and wastewater effluents were assayed. This work suggested that luxCDABE ‐marked Acinetobacter bacterium DF4/PUTK2 can be used to bioassay the ecotoxicity of wastewater and effluent samples contaminated with heavy metals. Using this assay, it is possible to pre‐select the more toxic samples for further chemical analysis and to discard wastewater samples with low or no inhibition because they are not toxic to the environment. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Lindane removal induction by Streptomyces sp. M7
Authors: Benimeli C. S. , Castro G. R. , Chaile A. P. , Amoroso M. J.
Published: September 2006

Gamma‐hexachlorocyclohexane (γ‐HCH or lindane), one of the most commonly used pesticides, has been mainly used in agriculture; this pesticide is known to be highly toxic and persistent, causing serious water and soil contamination. The objective of the present work is to study the effect of low glucose concentration and the addition of lindane at different growing time on the pesticide detoxification ability of Streptomyces M7.

After 96 h of incubation in synthetic medium containing glucose 0.6 g l–1 with the addition of lindane 100 μg l–1 at 20 h of incubation, a typical diauxic curve was obtained: glucose was the preferred substrate until 24 h, at 48 h, when the carbohydrate was depleted, the microorganism consumed the pesticide like carbon source. On the other hand, lindane removal induction was observed, which was greater when the pesticide was added to the medium at 20 h than 6 h of incubation. Between 72 and 96 h, a maximum of ∼86% of the Cl– was released when lindane was added to the medium at 20 h, whereas ∼70% and 67% Cl– was released in the medium when the pesticide was added at 0 and 6 h of incubation respectively. This is the first report of chloride release from inoculated medium supplemented with lindane, suggesting that the pesticide was degraded by Streptomyces sp. under aerobic conditions. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
New pFA‐cassettes for PCR‐based gene manipulation in Candida albicans
Authors: Schaub Yvonne , Dünkler Alexander , Walther Andrea , Wendland Jürgen
Published: September 2006

Several modules for efficient PCR‐based gene disruption have recently been introduced in Candida albicans. These are based on auxotrophic marker genes for deficient strains derived from SC5314/CAI4. Commonly used protocols for the transformation C. albicans are based either on the lithium acetate procedure or on electroporation also used for Saccharomyces cerevisiae. Here we present our updated arsenal of pFA‐modules that now include the heterologous marker genes HIS1 from C. dubliniensis and LEU2 from C. maltosa (Noble and Johnson 2005) and the dominant selection marker ca SAT1 (Reuss et al. 2004). We also introduce the Ashbya gossypii TEF1 ‐promoter as a strong constitutive promoter. With these new elements an enlarged collection of pFA‐marker and pFA‐marker‐promoter modules were generated containing 17 new modules. In addition, N‐terminal tagging with GFP‐(GA) 6 and epitope‐tagging modules using the 6 ×‐HIS‐tag were constructed. This adds to the previous modules that only enabled C‐terminal GFP‐tagging of genes (Gola et al. 2003). In total 29 pFA‐modules are currently freely available from our lab which – together with an update on the diagnostic verification procedure – further enlarge the C. albicans molecular toolbox and enhance our capabilities to use PCR‐based gene alteration methods in C. albicans. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Near‐surface‐temperature lapse rates on the Prince of Wales Icefield, Ellesmere Island, Canada: implications for regional downscaling of temperature
Authors: Marshall Shawn J. , Sharp Martin J. , Burgess David O. , Anslow Faron S.
Published: September 2006

Screen temperatures were monitored from May 2001 to April 2003 in an array of 25 sites on the Prince of Wales Icefield, Ellesmere Island, Canada. The observational network covered an area of ca 15 650 km2 and spanned an altitude ranging from 130 to 2010 m above sea level. The spatial array provides a record of near‐surface‐temperature lapse rates and mesoscale temperature variability on the icefield. The mean daily lapse rate in the 2‐year record is − 4.1° C km−1, with an average summer lapse rate of − 4.3° C km−1. Surface‐temperature lapse rates in the region are therefore systematically less than the free‐air lapse rates that are typically adopted for extrapolations of sea‐level temperature to higher altitudes. Steep lapse rates, resembling moist adiabatic rates in the free air (−6 to − 7° C km−1), are more common in summer at our site and are associated with enhanced cyclonic activity (low‐pressure and high relative vorticity) and southerly flow aloft. In contrast, northerly, anticyclonic flow prevails when summer lapse rates are weak (above − 2° C km−1). The low surface‐temperature lapse rates and their systematic synoptic variability have important implications for applications that require downscaling or extrapolation of surface‐ or boundary‐layer temperatures, such as modelling of glacier mass balance. We illustrate this in an analysis of observed versus modelled snowmelt on the icefield. Copyright © 2006 Royal Meteorological Society.
Climate Change detection over different land surface vegetation classes
Authors: Dang Hongyan , Gillett Nathan P. , Weaver Andrew J. , Zwiers Francis W.
Published: September 2006

A global land cover classification data set is used to divide the globe into seven regions to study surface temperature changes over different vegetation/surface classes. Statistically significant warming is found from the year 1900 over all regions (except for the ice sheets over Greenland and Antarctica). Outputs from three coupled climate models (CGCM2, HadCM2 and the Parallel Climate Model (PCM)) are used to examine the detection and attribution of surface temperature trends over the various vegetation classes for the past half century. An anthropogenic warming trend is detected in six of the seven regions. Observed trends are consistent with those simulated in response to greenhouse gas and sulfate aerosol forcing except over tropical forest and water where the models appear to overestimate the warming. The similarity between the resultant scaling factors for each region from the different models underscores the reliability of our detection results. Copyright © 2006 Royal Meteorological Society.
Variability of East African rainfall based on multiyear Regcm3 simulations
Authors: Anyah Richard O. , Semazzi Fredrick H. M.
Published: September 2006

The International Center for Theoretical Physics (ICTP) regional climate model version 3 (ICTP‐RegCM3) multiyear simulations of East Africa rainfall during the October–December, short rains season are evaluated. Two parallel runs; based on NCEP reanalysis and NASA FvGCM lateral boundary conditions are performed. The simulated monthly and seasonal rainfall climatology as well as the interannual variability are found to be fairly consistent with the observations. The model climatology over specific homogeneous climate subregions, except central Kenya (CKE) highlands, also reasonably agrees with the observed. The latitude‐time evolution (intraseasonal variability) of the simulated seasonal rainfall exhibits two distinct modes of behavior. The first is a quasistationary mode associated with high rainfall throughout the season within the equatorial belt between 1°S and 2°N. The second mode is associated with the intertropical convergence zone (ITCZ)‐driven southward migration of regions of rainfall maxima as the season progresses, which is also consistent with the observed. Furthermore, observed rainfall variability over distinct homogeneous climate subregions is also fairly reproduced by the model, except over central Kenya highlands and northeastern parts of Kenya. The spatial correlation between the simulated seasonal rainfall and some of the global teleconnections (DMI and Nino3.4 indices) shows that the regional model conserves some of the observed regional ‘hot spots’ where rainfall‐ENSO/DMI associations are strong. At the same time, unlike observations, the model reveals that along the East Africa Rift Valley and over western parts of the Lake Victoria Basin, the association is weak, perhaps an indication that nonlinear interactions between local forcing (captured by the model) and large‐scale systems either suppress or obscur the dominant influence of the teleconnections on rainfall over certain parts. Copyright © 2006 Royal Meteorological Society.
Sorption characteristics and performance of an acid dye on a gel‐type weak anion exchanger in a finite bath
Authors: Cabrera Rosa B , Fernandez‐Lahore Hector M
Published: September 2006

The sorption behaviour of carminic acid on a gel‐type weak anion exchanger was evaluated in a finite bath. Equilibrium and kinetic studies were employed to characterise the system. Adsorption isotherms were found to follow the Langmuir expression. Concentration–time profiles were obtained in a stirred vessel. The sorption kinetics was unaltered provided that the particle suspension criterion was met. Analytical equations were found for quantitative description of the system and to assist in scale‐up. Fluid‐side effects and intraparticle resistance mechanisms were revealed. The fluid‐side mass transfer coefficient (kf) took an almost constant value of 2.6 × 10−5 m s−1 under these experimental conditions. Amberlite IRA‐67, owing to its gel structure, was treated so as to present a homogeneous diffusion type, and a solid diffusivity (Ds) value of 3.16 × 10−10 m2 s−1 was determined experimentally. This value was insensitive to stirrer speed and could be considered constant for further design purposes. Overall mass transfer in the system showed a mixed nature with a balanced contribution of both resistances (δ ≈ 1). Copyright © 2006 Society of Chemical Industry
A nutrition and health perspective on almonds
Authors: Chen Chung‐Yen , Lapsley Karen , Blumberg Jeffrey
Published: September 2006

Almonds provide a nutrient‐dense source of vitamin E, manganese, magnesium, copper, phosphorus, fibre, riboflavin, monounsaturated fatty acids and protein. Although almost 50% of almond weight is fat, incremental intakes of 7 g day−1 of this tree nut reduce low‐density lipoprotein (LDL) cholesterol concentration by 1%, especially within the context of diets recommended by the National Cholesterol Education Program. Habitual almond consumption does not lead to weight gain, and their inclusion in low‐calorie diets appears to promote more weight loss than a comparable carbohydrate‐based low‐calorie diet. Also, almonds have a low glycemic index and do not adversely impact insulin sensitivity. Almonds are an excellent source of bioavailable α‐tocopherol, and increasing their intake enhances the resistance of LDL against oxidation. In addition, the polyphenolic constituents of almonds have been characterised recently and found to possess antioxidant actions. While benefits of almonds for cardiovascular health and obesity‐related diseases appear promising, the potential allergenic reaction among susceptible individuals can present a risk. Further research is required to achieve a better understanding of the role that the bioavailability and bioaccessibility of almond constituents and the synergy between them play in their associated health outcomes. Copyright © 2006 Society of Chemical Industry
Significance of sample preparation in developing analytical methodologies for accurate estimation of bioactive compounds in functional foods
Authors: Luthria Devanand L
Published: September 2006

Functional foods are defined as foods or food components that provide health benefits beyond basic nutrition (for the intended population). Increased interest in bioactive food components and phytochemicals has arisen from numerous epidemiological studies that suggest that certain phytochemicals can reduce risk of chronic diseases. Sales of functional foods containing high concentrations of bioactive components have increased dramatically during the past two decades. This paper illustrates with examples the significance of sample preparation in developing analytical methodologies for accurate estimation of potentially bioactive compounds present in functional foods using phenolic phytochemicals as model substrates. The primary three steps in any analysis are sampling, sample preservation, and sample preparation. These three initial steps are often overlooked and considered ‘as a means to an end’ and are often not well documented in the published literature. This paper outlines a systematic protocol for optimizing extraction of phytochemicals from different plant matrices. Accurate analysis of bioactive compounds is critical for their precise and reproducible quantification in different foods, establishing appropriate dietary intake and safety guidelines, and understanding their role in human health and nutrition. Copyright © 2006 Society of Chemical Industry
Current dietary exposure to polychlorodibenzo‐p‐dioxins, polychlorodibenzofurans, and dioxin‐like polychlorobiphenyls in Italy
Authors: Fattore Elena , Fanelli Roberto , Turrini Aida , di Domenico Alessandro
Published: September 2006

This study deals with an assessment of dietary exposure to polychlorodibenzo‐p‐dioxins (PCDDs), polychlorodibenzofurans (PCDFs), and dioxin‐like polychlorobiphenyls (DL‐PCBs) for the Italian general population, obtained by combining data from a national food consumption survey with contamination concentrations of European foodstuffs available on the market. The distribution of PCDD, PCDF, and DL‐PCB dietary intake(s) in the Italian population was investigated to assess to what extent the variability in dietary habits may cause higher exposures to the previously mentioned contaminants. Results indicate that the main contributions to total PCDD, PCDF, and DL‐PCB intake are due to fish and fish products (44%) and to milk and dairy products (27%). The mean PCDD, PCDF, and DL‐PCB intake (total toxic equivalents) via food was estimated 5.34, 3.37, and 2.28 pg World Health Organization (WHO)‐TE/kg of body weight (kg‐bw) per day for the three age groups 0–6 (breastfeeding excluded), 7–12, and 13–94 years old, respectively. The highest exposures due to variation in dietary habits are in general within a factor of 2–3. From the mean exposure estimated for the general population (adults), it can be inferred that a consistent part of it would exceed the tolerable daily intake of 2 pg WHO‐TE/kg‐bw adopted by the Scientific Committee on Food of the European Commission in 2001.
Dioxins, polychlorinated biphenyls and other organohalogen compounds in human milk. Levels, correlations, trends and exposure through breastfeeding
Authors: Fürst Peter
Published: September 2006

Polychlorinated dibenzo‐p‐dioxins (PCDD) and dibenzofurans (PCDF), together simplified termed “dioxins”, polychlorinated biphenyls (PCB), polybrominated diphenylethers (PBDE) and organochlorine pesticides constitute lipophilic, persistent organic pollutants that bioaccumulate in the food chain and consequently can be found in humans at considerable concentrations. During the past 30 years our institute analyzed far more than 2000 individual human milk samples for organochlorine pesticides and PCB and over 1000 specimens for PCDD/PCDF. The results of these analyses provide an overview and reliable basis as to contamination of human milk with these compounds, their correlations among each other, the temporal trend of exposure through breastfeeding and the predominant parameters that influence the maternal body burden. It was found that the levels of most persistent organohalogen compounds in human milk decreased significantly over the past three decades and equally did their exposure through breastfeeding. Exceptions are PBDE, which are still extensively used as flame‐retardants. PBDE levels in milk samples collected in the early 2000s are approximately 60% higher compared to specimens sampled 10 years before. Moreover, in contrast to PCB, PBDE show no significant correlation with PCDD/PCDF in human milk, which might be interpreted as an indication for another mode of human exposure.
A novel design of a CPW‐fed square slot antenna with broadband circular polarization
Authors: Chang Kow‐Ming , Lin Ren‐Jie , Deng I‐Chung , Chen Jin‐Bo , Xiang Ke Qing , Rong Chang Jun
Published: September 2006

A novel design of a broadband circularly polarized square slot antenna fed by a single coplanar waveguide is proposed and discussed. The circularly polarized radiation is achieved by means of using an outer rectangular ring and an inner rectangular ring at the center of a square slot. The proposed antenna has the fundamental resonant frequency of 2.44 GHz with the return loss of −40.93 dB, and it has the bandwidth of 3 dB axial ratio of 420 MHz or (17.21%). Details of the results are presented and discussed. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 2456–2459, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21951
Design of compact directive ultra wideband antipodal antenna
Authors: Abbosh A. M. , Kan H. K. , Bialkowski M. E.
Published: September 2006

In this paper, a novel design procedure for designing a compact UWB antipodal Vivaldi antenna is presented. The antenna operates over the UWB frequency band from 3.1 to more than 10.6 GHz. Its measured far‐field radiation is directive and its peak gain is 10.2 dBi in the specified band. The antenna pulse response shows negligible distortion, indicating that it can be useful in a precision ranging and imaging instrumentation. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 2448–2450, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21955
A compact harmonic‐suppressed Wilkinson power divider using C‐SCMRC resonators
Authors: Gu Jian‐Zhong , Yu Xiao‐Jing , Sun Xiao‐Wei
Published: September 2006

This letter describes a compact Wilkinson power divider using compensated spiral compact microstrip resonant cell (C‐SCMRC) resonators for harmonic suppression and size reduction. The size length of quarter wavelength transmission line is only 0.14 λg because of the slow‐wave characteristic. Furthermore, the proposed power divider rejected the 2nd and 3rd harmonic signals using the stopband of C‐SCMRC resonators. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 2382–2384, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21961
Compact broadband gap‐coupled rectangular microstrip antennas
Authors: Ray K. P. , Sevani V. , Kakatkar S.
Published: September 2006

Systematic investigations have been presented by splitting a single rectangular microstrip patch into equal, smaller elements along the width, keeping the length same. Of these, one of the elements is fed while others are gap coupled to its nonradiating edges. The rectangular patch is gradually splitted into 2–14 equal, smaller elements and in between coupling gaps are optimized for maximum bandwidth. Parametric study for the effect of gap and feed point location, along with radiation pattern, has also been carried out. A maximum bandwidth increment of over 10 times, compared with that of the original single rectangular patch is obtained for 14 numbers of equal strips. As the additional resonators (at same resonance frequency) are obtained from the original patch itself, the overall configuration remains compact. Experiments have been carried out, which are in good agreement with simulated results. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 2382–2384, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21976
On the constitutive relations of G‐chiral media and the possibility to realize negative‐index media
Authors: Qiu Cheng‐Wei , Yao Hai‐Ying , Zouhdi Saïd , Li Le‐Wei , Leong Mook‐Seng
Published: September 2006

Gyro‐chiral (G‐chiral) media of different constitutive relations are studied as potential materials to realize the negative‐index material (NIM). G‐chiral media are believed to have advantages over chiral media: negative refractive index and backward waves can be achieved without requiring the permittivity and permeability to be quite small at working frequency. The gyrotropic parameters favor the realization of NIM far off the resonances of the permittivity and permeability. The possibility of obtaining backward waves and negative refractive index under Post's and Tellegen's relations are discussed. Moreover, the mapping and comparison of G‐chiral media of these two relations have been studied. It is found that the Tellegen's relations are more suitable to describing the G‐chiral media so as to realize NIM by this kind of medium. Therefore, this paper not only provides an alternative way to achieve NIM from the G‐chiral medium but also discusses the constitutive relation's effects on backward wave propagation and refractive indices. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48:2534–2538, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21981
Microwave devices based on transmission lines with positive/negative dispersion
Authors: Vendik I. B. , Kholodnyak D. V. , Kolmakova I. V. , Serebryakova E. V. , Kapitanova P. V.
Published: September 2006

Additional degrees of freedom in a design of miniature microwave devices can be provided by a combination of right‐handed and left‐handed transmission lines, which differ in dispersion characteristics. We present some examples of such devices: planar resonator and filter with suppressed spurious response, miniaturized balun, and broadband digital phase shifters. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 2632–2638, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21985
Designing materials with desired electromagnetic properties
Authors: Bulu Irfan , Caglayan Humeyra , Ozbay Ekmel
Published: September 2006

In this work, we suggest and demonstrate a robust method to tune the plasma frequencies of wire mediums. The method we suggest involves the use of two or more wire arrangements in the unit cell. By incorporating the method we suggested it is possible to tune the plasma frequencies of wire mediums effectively by use of lower metal densities. In addition, we study the effective permittivities and permeabilities of labyrinth based metamaterials. Our results show that the effective permeability of the labyrinth based metamaterial medium is negative above a certain frequency. The results of the effective permittivity calculations for the labyrinth based metamaterial medium reveal that the labyrinth structure exhibits a strong dielectric response near the magnetic resonance frequency. Finally, we design labyrinth based left‐handed mediums that have several desired properties such as simultaneous μ, ϵ = −1 and μ, ϵ = 0. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 2611–2615, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21988
Experimental investigation of radiation properties of an antenna embedded in low permittivity thin‐wire‐based metamaterial
Authors: Bonefačić Davor , Hrabar Silvio , Kvakan Dražen
Published: September 2006

Experimental results regarding the increase in directivity and gain of an antenna embedded in low‐permittivity two‐dimensional anisotropic thin‐wire‐based metamaterial are presented. As expected, increase in directivity and gain has been observed. The effect of main beam splitting with frequency increase, predicted by theoretical analysis, has been confirmed. The influence of the number of layers forming the metamaterial on the radiation pattern and gain has been investigated. Input impedance was measured both as a function of frequency and of the number of wire layers forming the metamaterial. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 2581–2586, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21994
Optimization of metamaterial based subwavelength cavities for ultracompact directive antennas
Authors: Ourir A. , de Lustrac A. , Lourtioz J.‐M.
Published: September 2006

Artificial magnetic conductors (AMC) are proposed for the fabrication of subwavelength cavities in the microstrip technology. These metamaterials can simultaneously present a low phase value at reflection and a high impedance for normal incident waves over a wide frequency band. Planar cavities using AMC‐based reflectors are applicable to the design of ultracompact directive antennas. An optimized cavity structure is presently shown to provide a significant enhancement of the gain and directivity of a microstrip antenna near 10 GHz. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 2573–2577, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21996
Isotropic artificial media with simultaneously negative permittivity and permeability
Authors: Vendik Irina , Vendik Orest , Odit Mikhail
Published: September 2006

A composite medium consisting of two sublattices of dielectric spherical particles of high permittivity and different radii embedded in a dielectric matrix of smaller permittivity are considered. It has been shown that such a composite medium reveals properties of an isotropic double negative media in the frequency range where resonance oscillations of H111 mode in one kind of particles and E111 mode in another kind of particles are excited simultaneously. The E111 resonance and the H111 resonance give rise to the magnetic dipole momentum and the electric dipole momentum correspondingly. Averaging the magnetic momentum and the electric momentum over the cells belonging to the appropriate spherical particles reveals the negative permittivity and permeability. Distribution of the electromagnetic wave outside the sphere was calculated. Influence of dispersion of the sphere permittivity and size on the effective parameters was estimated. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 2553–2556, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22002
Radiation enhancement and radiation suppression by a left‐handed metamaterial
Authors: Boardman A. D. , Marinov K.
Published: September 2006

The perfect lens property of a dispersive and lossy left‐handed metamaterial disk is exploited to superimpose a source of electromagnetic radiation onto its mirror image, formed as a result of reflection from a perfect electric conductor or a perfect magnetic conductor. The superposition of a vertical wire‐dipole antenna with its perfect electric conductor image results in an increase of the radiation resistance of the antenna compared with that of an antenna emitting in free space. On the other hand, if the same antenna is coupled to a perfect magnetic conductor image, it is shown that the result is the formation of a nonradiating configuration. The finite‐difference time‐domain analysis is performed, and this allows a detailed characterization of the systems. It is shown that the nonradiating system allows relatively large amounts of electromagnetic energy to be stored in the left‐handed metamaterial disk and that is indicative of strong electromagnetic fields inside the material. This property is employed in a second‐harmonic generation process and the potential of a nonradiating configuration as an efficient nonlinear device is demonstrated. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48:2512–2516, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22010
Left‐handed and right‐handed transmission properties of microstrip lines loaded with complementary split rings resonators
Authors: Gil Ignacio , Bonache Jordi , Gil Marta , García‐García Joan , Martín Ferran
Published: September 2006

In this work, microstrip lines loaded with complementary split rings resonators (CSRRs) and series capacitive gaps are modeled by means of a lumped element equivalent circuit. The structures exhibit a left‐handed (or backward wave) behavior at low frequencies, followed by forward transmission at higher frequencies separated by a forbidden band. The equivalent circuit model is able to accurately describe the frequency responses of the structures in the left‐handed transmission band, the forbidden band, and the lower frequency region of the forward allowed band. The limitations of this circuit model to properly predict the behavior of the structures at higher frequencies (mainly related to the Bragg effect caused by periodicity) are pointed out. This work can be of interest for the design of microwave circuits based on CSRR metamaterials. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 2508–2511, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22011
A double‐blind, randomized controlled trial of cystometry using saline versus 0.3 M potassium chloride infusion in women with overactive bladder syndrome
Authors: Philip Joe , Willmott Sasithorn , Owen Delyth , Samsudin Cathy , Irwin Paul P.
Published: September 2006

Aim

To evaluate the effect of 0.3 M potassium chloride on cystometric parameters by comparing it with normal saline as a filling solution in women with overactive bladder (OAB).

Patients and Methods

Twenty‐three women with significant OAB symptoms underwent consecutive cystometrograms (CMGs) using 0.9% normal saline (NS) and 0.3 M potassium chloride (KCl), the order of which was randomized for each patient. Individual CMGs were performed by separate investigators and both patients and investigators were blinded to the order in which each solution was given and to the results of the other CMG.

Results

Regardless of the nature of the filling solution, the order in which the CMGs were performed had little influence on either first desire to void (FDV, mean 83.5 ml vs. 117.8 ml for first and second CMGs respectively, P = 0.10) or on maximum cystometric capacity (Cmax, mean 265.0 ml vs. 264.4 ml, P = 0.98). KCl produced a significant (24%) reduction in mean Cmax compared to NS (mean 228.6 ml vs. 300.8 ml, P = 0.001), irrespective of the order of infusion.

Conclusion

This comparative study using 0.3 M KCl versus NS as filling solutions suggests that intravesical potassium may not simply act on urothelial sensory nerve endings; it may also stimulate detrusor muscle contraction. These findings may influence the interpretation of the potassium sensitivity test in patients with OAB symptoms, particularly in those suspected of having interstitial cystitis. Neurourol. Urodynam. © 2006 Wiley‐Liss, Inc.
Correlation between motor function and lower urinary tract dysfunction in patients with infantile cerebral palsy
Authors: Bross Stephan , Honeck Patrick , Kwon Sun Tscheol , Badawi Jasmin Katrin , Trojan Lutz , Alken Peter
Published: September 2006

Aims

The aim of this study was to evaluate urodynamic findings in patients with infantile cerebral palsy (CP) and to correlate the findings with impaired motor function.

Methods

We conducted a videourodynamic investigation on a highly select group of 29 patients (3–53 years). Motor function was assessed in each patient by the Gross Motor Function Classification System for CP (GMFCS). With this system, motor function is divided into five levels: patients in Level I have the most independent motor function and patients in Level V the least. The patients were divided into Group 1 (23 symptomatic patients with recurrent urinary tract infection or urinary incontinence) and Group 2 (6 asymptomatic patients).

Results

In Group 1, 21 patients (91%) had reduced compliance (0.6–16.4 ml/cmH2O) and 16 patients (70%) had increased DLPP (>40 cmH2O). Detrusor overactivity and pelvic floor overactivity were found in all 23 patients. In Group 2, two patients (33%) had reduced compliance (0.7 and 5.8 ml/cmH2O) and four (67%) had increased DLPP (>40 cm H2O). Detrusor overactivity and pelvic floor overactivity were observed in five patients (83%). Symptomatic patients showed higher GMFCS levels than asymptomatic patients. In the group of asymptomatic patients, there was no one classified as Levels IV or V, while there were no symptomatic patients classified as Level I.

Conclusions

We conclude that urinary symptoms and pathological urodynamic findings increase along with the degree of motor function impairment shown by the GMFCS. Pathologic urodynamic findings can be found in both symptomatic and in asymptomatic patients. Neurourol. Urodynam. 26:222–227, 2007. © 2006 Wiley‐Liss, Inc.
Brainstem primitive neuroectodermal tumors (bstPNET): Results of treatment with intensive induction chemotherapy followed by consolidative chemotherapy with autologous hematopoietic cell rescue
Authors: Fangusaro Jason R. , Jubran Rima F. , Allen Jeffrey , Gardner Sharon , Dunkel Ira J. , Rosenblum Mark , Atlas Mark P. , Gonzalez‐Gomez Ignacio , Miller Douglas , Finlay Jonathan L.
Published: September 2006

We have evaluated the response rate and survival utilizing intensified chemotherapy followed by myeloablative chemotherapy with autologous hematopoietic cell rescue (AuHCR) and adjuvant radiation therapy in six young children with newly diagnosed brainstem primitive neuroectodermal tumors (bstPNET). Following maximum surgical resection of the tumor, patients received high dose induction chemotherapy including vincristine, cisplatin, cyclophosphamide, and etoposide. Eligible patients received a single cycle of myeloablative chemotherapy followed by AuHCR. Two patients survive at least 32 months with stable disease. This approach provides an alternative for young patients with bstPNET who in prior reports have had a uniformly fatal prognosis. Pediatr Blood Cancer 2008;50:715–717. © 2006 Wiley‐Liss, Inc.
Impact of an education program on late diagnosis of retinoblastoma in Honduras
Authors: Leander Christopher , Fu Ligia C. , Peña Armando , Howard Scott C. , Rodriguez‐Galindo Carlos , Wilimas Judith A. , Ribeiro Raul C. , Haik Barrett
Published: September 2006

Background

In developed countries, more than 90% of children with retinoblastoma present with limited‐stage disease and are cured; however, in countries with limited resources, like Honduras, most patients present with advanced disease and cure rates are less than 50%. Early diagnosis is necessary to improve the survival of children with retinoblastoma in these countries.

Procedure

We describe the preliminary results of a retinoblastoma education program linked to a national vaccination campaign in Honduras. Posters and flyers were designed to be accessible to poorly educated readers, to convey the severity of retinoblastoma, and to provide contact information. Charts and an electronic database were reviewed to determine age at diagnosis, presenting signs and symptoms, date of diagnosis, and outcome.

Results

During the eight previous years (July 1995–June 2003), 73% of the 59 diagnosed cases of retinoblastoma were extraocular; in contrast, during the post‐campaign period (June 2003–January 2005), only 35% of the 23 diagnosed cases showed extraocular spread (P = 0.002). More than one‐third of patients in both time periods either refused therapy or abandoned treatment.

Conclusion

This inexpensive approach is an effective first step toward improving survival of childhood retinoblastoma. Abandonment and refusal of therapy are continuing obstacles. Pediatr Blood Cancer 2007;49:817–819. © 2006 Wiley‐Liss, Inc.
Young siblings of children with cancer deserve care and a personalized approach
Authors: Massimo Luisa M. , Wiley Thomas J.
Published: September 2006

The youngest siblings may be both emotionally vulnerable and often neglected members of the family of a childhood cancer patient. The prompt identification of signs of distress in these subjects allows trained caregivers to intervene with personalized, age‐appropriate, attention, and care. A narrative approach, based on personalized listening, writings, and spontaneous drawings, can provide the means to elicit markers of psychological maladjustment in even the youngest of siblings. Two exemplary cases are reported to illustrate this approach. Pediatr Blood Cancer 2008;50:708–710. © 2006 Wiley‐Liss, Inc.