bluuebunny/crossref_metadata_2025 huggingface dataset:
Clonal diploid sperm of the diploid‐triploid mosaic loach, Misgurnus anguillicaudatus (Teleostei:Cobitidae)
Authors: Morishima Kagayaki , Oshima Kouzou , Horie Shin , Fujimoto Takafumi , Yamaha Etsuro , Arai Katsutoshi
Published: June 2004

The loach Misgurnus anguillicaudatus comprises diploid, triploid and diploid‐triploid mosaic individuals in a wild population of the Hokkaido island, Japan. Previous studies revealed the presence of a cryptic clonal lineage among diploid loaches, which is maintained by uniparental reproduction of genetically identical diploid eggs. In the present study, we analyzed distribution and genetic status of diploid and triploid cells in infrequent mosaic males. Flow cytometry, microsatellite genotyping and DNA fingerprinting verified that mosaic males consisted of diploid cells with genotypes identical to the natural clone and triploid cells with diploid genomes of the clonal lineage plus haploid genome from sperm nucleus of the father. Thus, the occurrence of diploid‐triploid mosaicism might be caused by accidental fertilization of a diploid blastomere nucleus with haploid sperm after the initiation of clonal development of unreduced eggs. Such mosaic males produced fertile sperm with diploid DNA content. The experimental cross between normal diploid female and diploid‐triploid mosaic male gave rise to the appearance of triploid progeny which exhibited two microsatellite alleles identical to the clonal genotype and one allele derived from the normal female. In DNA fingerprinting, such triploid progeny gave not only all the DNA fragments from the clone, but also other fragments from the normal female. Induced androgenesis using UV irradiated eggs and sperm of the mosaic male gave rise to the occurrence of diploid individuals with paternally derived microsatellite genotypes and DNA fingerprints, absolutely identical to the natural clonal lineage. These results conclude that the diploid‐triploid mosaic male produced unreduced diploid sperm with genetically identical genotypes. The spermatogenesis in the clonal diploid cells under the mosaic condition suggests that triploid male somatic cells might transform genetically all‐female germ cells to differentiate into functionally male gametes. The discovery of the mosaic male producing unreduced sperm suggests the theoretical occurrence of triploids and other polyploids by the syngamy of such paternally derived diploid gametes. J. Exp. Zool. 301A:502–511, 2004. © 2004 Wiley‐Liss, Inc.
Molecular cloning of a putative membrane form guanylyl cyclase from the crayfish Procambarus clarkii
Authors: Liu Hui‐Fen , Lai Chi‐Yung , Watson R. Douglas , Lee Chi‐Ying
Published: June 2004

Available data indicate that crustacean hyperglycemic hormone (CHH) stimulates membrane‐bound guanylyl cyclase (GC), producing cyclic guanosine 3′,5′–monophosphate, which in turn mediates the effect of CHH on carbohydrate metabolism. In the present study, we report the cloning of a cDNA (PcGC‐M2) encoding a putative membrane form GC from the muscle of the crayfish, Procambarus clarkii. Analysis of the deduced amino acid sequence shows that PcGC‐M2 contains the signature domains characteristic of membrane form GCs, including an extracellular ligand‐binding domain, a single transmembrane, and intracellular kinase‐like and cyclase catalytic domains. In addition, a C‐terminal domain of 247 residues is present following the cyclase catalytic domain. PcGC‐M2 is most closely related (33% identity) to a Drosophila membrane form GC (DrGC–1), and an Anopheles gambiae membrane form GC (AgaGC); the three GCs also share a similar distribution pattern of conserved cysteine residues in the extracellular domain. The PcGC‐M2 transcript is expressed in several CHH target tissues, including muscle, hepatopancreas, heart, ovary, testis, and gill, suggesting that PcGC‐M2 may participate in the signaling cascade activated by CHH. J. Exp. Zool. 301A:512–520, 2004. © 2004 Wiley‐Liss, Inc.
Progesterone determination in Iberian red deer by time‐resolved fluorometry: An alternative method to RIA
Authors: Parra María Dolores , García Andrés José , Bernal Luis Jesús , Landete‐Castillejos Tomás , Cerón José Joaquín
Published: June 2004

The validation for Iberian red deer of a commercially available Time‐resolved fluoroimmunoassay (TR‐FIA) designed for analysis of progesterone in human beings was carried out. Intra‐assay coefficients of variation ranged from 3.6% to 7.4%, while inter‐assay coefficients of variation varied from 5.2% to 15.5%. Accuracy, evaluated by comparing results yielded by TR‐FIA with those obtained from a validated radioimmunoassay (RIA) in the measurement of 14 samples, provided a high regression coefficient (R2= 0.93). Different progesterone concentrations added to pool plasma showed percentages of recovery that ranged between 102.6% and 82.48%. The limit of detection was 0.102 nmol/L. The results obtained indicate that the present method is suitable for the measurement of progesterone in female Iberian red deer. J. Exp. Zool. 301A:472–476, 2004. © 2004 Wiley‐Liss, Inc.
Regrowth of the stalk of the Sea lily, Metacrinus rotundus (Echinodermata: Crinoidea)
Authors: Nakano Hiroaki , Hibino Taku , Hara Yuko , Oji Tatsuo , Amemiya Shonan
Published: June 2004

Sea lilies are critical to understanding the evolution of the echinoderm body plan, because they are the only extant group whose adults possess a stalk, a prevalent feature in the radiation of a number of primitive echinoderm lineages. Extensive crown regeneration ability has been reported in Metacrinus rotundus, but the regenerative potential of the stalk has never been determined in any species of sea lilies. In this study, we show that M. rotundus whose stalks have been completely excised are capable of stalk regeneration. The process is similar to the growth of the original stalk, but much slower, and the regenerated stalks are not morphologically identical to the original stalk. Since stalk regeneration, in contrast to well‐studied regeneration events, probably requires little additional activation of morphogenetic programs, we refer to the stalk regeneration phenomenon as “stalk regrowth” to distinguish it as a special form of regeneration. Since specimens whose entire stalk below the basal plates had been removed were able to regrow, the basal plates, and probably the aboral nerve center within them, are essential for stalk regrowth. Sea lily stalk regrowth is described in detail, and the evolution of feather stars is discussed in light of the growth pattern of the sea lily stalk. J. Exp. Zool. 301A:464–471, 2004. © 2004 Wiley‐Liss, Inc.
Growth enhancement and food conversion efficiency of transgenic fish Labeo rohita
Authors: Venugopal Thayanithy , Anathy Vikas , Kirankumar Santhakumar , Pandian Thavamani Jegajothivel
Published: June 2004

Three family lines of fast growing transgenic rohu Labeo rohita (rohu) were generated by electroporated‐sperm‐mediated transfer of the vectors harboring CMV promoter or grass carp β‐actin promoter fused to endogenous rohu GH (rGH) cDNA. The gene transfer efficiency was 25%. The transgenic rohu (family line 1) with CMV promoter showed a growth enhancement of four times normal size, whereas those (family lines 2 and 3) generated with β‐actin promoter grew 4.5 and 5.8 times faster than their respective control siblings. Southern analysis confirmed the transgene extrachromosomal (Te) persistence until the 60th week in family 1. The individuals of family lines 2 and 3, however, showed integration (Ti), as well as persistence as extarchromosomal copies (Te) until the age of 30 weeks. Mosaicism of the transgene was shown at the levels of its presence and expression. The ectopic expression of rGH mRNA was confirmed by RT‐PCR. Feeding experiments revealed that the transgenic rohu ate food at a lower rate but grew more efficiently than their control siblings. J. Exp. Zool. 301A:477–490, 2004. © 2004 Wiley‐Liss, Inc.
α‐Tubulin and acetylated α‐tubulin during ovarian follicle differentiation in the lizard Podarcis sicula Raf.
Authors: Maurizii Maria Gabriella , Alibardi Lorenzo , Taddei Carlo
Published: June 2004

During most of the previtellogenic oocyte growth, the follicular epithelium of the lizard Podarcis sicula shows a polymorphic structure, due to the presence of different follicle cells. These include small cells which divide and move from the periphery of the follicle to the oocyte surface, intermediate cells which represent an initial step in the process of cell enlargement, and large pyriform cells engaged in the transport of different materials to the oocyte through intercellular bridges. We have studied, by immunolocalization and immunoblotting, the localization of α‐tubulin and its acetylated form in different follicle cells and in the oocyte during the main steps of ovarian follicle differentiation. Our results indicate that α‐tubulin is present in all follicle cells at different stages of ovarian follicle differentiation, while its acetylated form is detectable exclusively in the small proliferating and migrating follicle cells. In pyriform cells, α‐tubulin is localized around the nucleus, extends to the cell apex, and crosses the zona pellucida into the oocyte cortex. The presence of acetylated tubulin in the small follicle cells may be related to the proliferation and/or migration of these cells. The absence of acetylated tubulin form in the cytoplasm of intermediate and pyriform cells can be related to the colocalization of α‐tubulin with the keratin cytoskeleton in these cells, as detected by confocal microscopy. We have also identified the colocalization of α‐tubulin with keratin in the cortical region of the oocyte, in particular when the cortex is engaged in the uptake of the yolk proteins. J. Exp. Zool.301A:532–541, 2004. © 2004 Wiley‐Liss, Inc.
Influence of photoperiod and temperature on reproductive mode in the Brine shrimp, Artemia franciscana
Authors: Nambu Ziro , Tanaka Shin , Nambu Fumiko
Published: June 2004

Brine shrimp, Artemia, exhibit two modes of reproduction: oviparity (diapause cyst production) and ovoviviparity (live larvae release). Environmental conditions determining these developmental routes are poorly understood, so we investigated the effects of photoperiod and temperature on reproductive mode. Nauplii of A. franciscana were hatched from cysts produced in the Great Salt Lake, Utah, and raised in 2% natural sea salt water under photoperiods of 24, 14, 12, or 10 h at 28° or 20°C. Mating pairs of mature shrimp were isolated and reared continuously under those conditions. The mode of reproduction shown by each pair was determined daily throughout their life span, and found to be greatly affected by photoperiod, and less influenced by temperature. The relative degree of oviparity increased as the photoperiod became shorter at both temperatures. In contrast, the degree of ovoviviparity was higher as the photoperiod became longer at both temperatures. The critical photoperiod appears to be between 12 and 14 h. For all photoperiods examined, the degree of oviparity was higher at 28°C than at 20°C, whereas the degree of ovoviviparity was greater at 20°C than at 28°C. J. Exp. Zool. 301A:542–546, 2004. © 2004 Wiley‐Liss, Inc.
Seasonal effects of dehydration on glucose mobilization in freeze‐tolerant chorus frogs (Pseudacris triseriata) and freeze‐intolerant toads (Bufo woodhousii and B. cognatus)
Authors: Edwards Joshua Ronald , Jenkins Jennifer Lynn , Swanson David Leslie
Published: June 2004

It has been hypothesized that freeze‐tolerance in anurans evolved from a predisposition for dehydration tolerance. To test this hypothesis, we dehydrated summer/fall‐collected and winter acclimated freeze‐tolerant chorus frogs and dehydration‐tolerant, but freeze‐intolerant, Woodhouse's and Great Plains toads to 25% and 50% body water loss (BWL). Following treatments, we measured glucose, glycogen, and glycogen phosphorylase and glycogen synthetase (summer/fall only) activities in liver and leg muscle. Hepatic glucose levels were not significantly altered by dehydration in either summer/fall‐collected frogs or toads. Conversely, winter acclimated frogs did show an increment (2.9–fold) in hepatic glucose with dehydration, accompanied by a reduction in hepatic glycogen levels. Winter acclimated toads did not mobilize hepatic glucose in response to dehydration. Further, hepatic glycogen and phosphorylase activities did not vary in any consistent manner with dehydration in winter toads. Mean leg muscle glucose values were elevated at 50% BWL relative to other treatments, significantly so compared to 25% BWL for summer/fall‐collected frogs. The pattern of hepatic glucose mobilization with dehydration in winter frogs is consistent with that in other freeze‐tolerant frog species, and provides additional support for the hypothesis that freezing tolerance evolved from a capacity for dehydration tolerance. However, the lack of hepatic glucose mobilization in response to dehydration in fall frogs suggests that a seasonal component to dehydration‐induced regulation of glucose metabolism exists in chorus frogs. Furthermore, the absence of a dehydration‐induced mobilization of hepatic glucose at both seasons in toads suggests that this dehydration response is not universal for terrestrial anurans. J. Exp. Zool. 301A:521‐531, 2004. © 2004 Wiley‐Liss, Inc.
Dual‐regulated myoD‐ and msx1‐based interventions in C2C12‐derived cells enable precise myogenic/osteogenic/adipogenic lineage control
Authors: Fux Cornelia , Langer Dominik , Fussenegger Martin
Published: June 2004

Background

Advanced gene therapy, tissue engineering and biopharmaceutical manufacturing require sophisticated and well‐balanced multiregulated multigene interventions to reprogram desired mammalian cell phenotypes.

Methods

We have combined the streptogramin (PIP)‐ and tetracycline (TET)‐responsive gene regulation systems for independent expression control of the differentiation determinants myoD and msx1 in C2C12‐derived cells.

Results

Different dual‐regulated expression scenarios which induce either both, only one or none of the lineage control genes triggered differential differentiation and precise control of myogenic, osteogenic or adipogenic cell phenotypes.

Conclusions

Our findings substantiate the use of multiregulated multigene interventions in reprogramming cellular differentiation pathways in a desired manner. Copyright © 2004 John Wiley & Sons, Ltd.
Towards a therapeutic inhibition of dystrophin exon 23 splicing in mdx mouse muscle induced by antisense oligoribonucleotides (splicomers): target sequence optimisation using oligonucleotide arrays
Authors: Graham Ian R. , Hill Vanessa J. , Manoharan Muthiah , Inamati Gopal B. , Dickson George
Published: June 2004

Background

The activity of synthetic antisense oligonucleotides (splicomers) designed to block pre‐mRNA splicing at specific exons has been demonstrated in a number of model systems, including constitutively spliced exons in mouse dystrophin RNA. Splicomer reagents directed to Duchenne muscular dystrophy (DMD) RNAs might thus circumvent nonsense or frame‐shifting mutations, leading to therapeutic expression of partially functional dystrophin, as occurs in the milder, allelic (Becker) form of the disease (BMD).

Methods

Functional and hybridisation array screens have been used to select optimised splicomers directed to exon 23 of dystrophin mRNA which carries a nonsense mutation in the mdx mouse. Splicomers were transfected into cultured primary muscle cells, and dystrophin mRNA assessed for exon exclusion. Splicomers were also administered to the muscles of mdx mice.

Results

Oligonucleotide array analyses with dystrophin pre‐mRNA probes revealed strong and highly specific hybridisation patterns spanning the exon 23/intron 23 boundary, indicating an open secondary structure conformation in this region of the RNA. Functional screening of splicomer arrays by direct analysis of exon 23 RNA splicing in mdx muscle cultures identified a subset of biologically active reagents which target sequence elements associated with the 5′ splice site region of dystrophin intron 23; splicomer‐mediated exclusion of exon 23 was specific and dose‐responsive up to a level exceeding 50% of dystrophin mRNA, and Western blotting demonstrated de novo expression of dystrophin protein at 2–5% of wild‐type levels. Direct intramuscular administration of optimised splicomer reagents in vivo resulted in the reappearance of sarcolemmal dystrophin immunoreactivity in > 30% of muscle fibres in the mdx mouse

Conclusions

These results suggest that correctly designed splicomers may have direct therapeutic value in vivo, not only for DMD, but also for a range of other genetic disorders. Copyright © 2004 John Wiley & Sons, Ltd.
Optimization of in vitro vascular cell transfection with non‐viral vectors for in vivo applications
Authors: Elmadbouh Ibrahim , Rossignol Patrick , Meilhac Olivier , Vranckx Roger , Pichon Chantal , Pouzet Bruno , Midoux Patrick , Michel Jean‐Baptiste
Published: June 2004

Background

Syngeneic vascular cells are interesting tools for indirect gene therapy in the cardiovascular system. This study aims to optimize transfection conditions of primary cultures of vascular smooth muscle cells (VSMCs) using different non‐viral vectors and zinc as an adjuvant and to implant these transfected cells in vivo.

Methods

Non‐liposomal cationic vectors (FuGene™6), polyethylenimines (ExGen™500), and histidylated polylysine (HPL) were used as non‐viral vectors in vitro with secreted alkaline phosphatase (SEAP) as reporter gene. Transfection efficiency was compared in cultured rat, rabbit and human VSMCs and fibroblasts. Zinc chloride (ZnCl2) was added to optimize transfection of rat VSMCs in vitro which were then seeded in vivo.

Results

Much higher SEAP levels were obtained in rabbit cells with FuGene™6 (p < 0.0001) at day 2 than in equivalent rat and human cells. Rat VSMCs transfected in vitro with FuGene™6 and ExGen™500 expressed higher SEAP levels than with HPL. In rat VSMCs, SEAP secretion was more than doubled by addition of 250 µM ZnCl2 (p < 0.0001) for all vectors. Seeding of syngeneic VSMCs transfected under optimized conditions (FuGene™6/pcDNA3‐SEAP +250 µM ZnCl2) into healthy Lewis rats using various routes or into post‐infarct myocardial scar resulted in a peak of SEAP expression at day 2 and detectable activity in the plasma for at least 8 days.

Conclusions

FuGene™6 is an efficient non‐viral transfection reagent for gene transfer in somatic smooth muscle cells in vitro and ZnCl2 enhances its efficiency. This increased expression of the transgene product is maintained after seeding in vivo. Copyright © 2004 John Wiley & Sons, Ltd.
Sustained transgene expression by human cord blood derived CD34+ cells transduced with simian immunodeficiency virus agmTYO1‐based vectors carrying the human coagulation factor VIII gene in NOD/SCID mice
Authors: Kikuchi Jiro , Mimuro Jun , Ogata Kyoichi , Tabata Toshiaki , Ueda Yasuji , Ishiwata Akira , Kimura Konzoh , Takano Katsuhiro , Madoiwa Seiji , Mizukami Hiroaki , Hanazono Yutaka , Kume Akihiro , Hasegawa Mamoru , Ozawa Keiya , Sakata Yoichi
Published: June 2004

Background

An Erratum has been published for this article in Journal of Gene Medicine 7(6), 2005, 836.

Gene therapy is being studied as the next generation therapy for hemophilia and several clinical trials have been carried out, albeit with limited success. To explore the possibility of utilizing autologous bone marrow transplantation of genetically modified hematopoietic stem cells for hemophilia gene therapy, we investigated the efficacy of genetically engineered CD34+ cell transplantation to NOD/SCID mice for expression of human factor VIII (hFVIII).

Methods

CD34+ cells were transduced with a simian immunodeficiency virus agmTYO1 (SIV)‐based lentiviral vector carrying the enhanced green fluorescent protein (eGFP) gene (SIVeGFP) or the hFVIII gene (SIVhFVIII). CD34+ cells transduced with SIV vectors were transplanted to NOD/SCID mice. Engraftment of transduced CD34+ cells and expression of transgenes were studied.

Results

We could efficiently transduce CD34+ cells using the SIVeGFP vector in a dose‐dependent manner, reaching a maximum (99.6 ± 0.1%) at MOI of 5 × 103 vector genome/cell. After transducing CD34+ cells with SIVhFVIII, hFVIII was produced (274.3 ± 20.1 ng) from 106 CD34+ cells during 24 h in vitro incubation. Transplantation of SIVhFVIII‐transduced CD34+ cells (5–10 × 105) at a multiplicity of infection (MOI) of 50 vector genome/cell into NOD/SCID mice resulted in successful engraftment of CD34+ cells and production of hFVIII (minimum 1.2 ± 0.9 ng/mL, maximum 3.6 ± 0.8 ng/mL) for at least 60 days in vivo. Transcripts of the hFVIII gene and the hFVIII antigen were also detected in the murine bone marrow cells.

Conclusions

Transplantation of ex vivo transduced hematopoietic stem cells by non‐pathogenic SIVhFVIII without exposure of subjects to viral vectors is safe and potentially applicable for gene therapy of hemophilia A patients. Copyright © 2004 John Wiley & Sons, Ltd.
Needleless in vivo gene transfer into muscles by jet injection in combination with electroporation
Authors: Horiki Mayumi , Yamato Eiji , Ikegami Hiroshi , Ogihara Toshio , Miyazaki Jun‐ichi
Published: June 2004

Previously, we have established an in vivo electroporation method for gene transfer into muscle by injection of DNA with a needle followed by electric pulse delivery using needle‐type electrodes and proved that this method is effective for the systemic delivery of cytokines. To perform the needleless gene delivery, we combined jet injection of DNA with electroporation using plate‐type electrodes. For delivery of β‐galactosidase‐ and enhanced green fluorescent protein (EGFP)‐expressing plasmids into muscles, there was no significant difference between the previous needle‐mediated method and the newly developed jet‐injection method. When pCAGGS‐IL‐5 was introduced into tibialis anterior, quadricipital and back sural muscles by this new method, the serum IL‐5 levels reached 3.4 ± 0.9, 5.7 ± 1.7 and 8.4 ± 2.7 ng/ml at day 5, respectively. Although the peak values of IL‐5 achieved by the jet‐injection method in these muscles were lower than that of the highest value achieved by needle‐mediated gene delivery into anterior tibial muscle, this new method could deliver plasmid into relatively large muscles with better efficiency than the needle‐mediated method. Thus the jet‐injection method provides a useful means of gene delivery into large muscles, which is essential for future use in human gene therapy. Copyright © 2004 John Wiley & Sons, Ltd.
The crossing number of Cm × Cn is as conjectured for n ≥ m(m + 1)
Authors: Glebsky Lev Yu. , Salazar Gelasio
Published: May 2004

It has been long conjectured that the crossing number of Cm × Cn is (m−2)n, for all m, n such that n ≥  m ≥  3. In this paper, it is shown that if n ≥  m(m + 1) and m ≥  3, then this conjecture holds. That is, the crossing number of Cm × Cn is as conjectured for all but finitely many n, for each m. The proof is largely based on techniques from the theory of arrangements, introduced by Adamsson and further developed by Adamsson and Richter. © 2004 Wiley Periodicals, Inc. J Graph Theory 47: 53–72, 2004
Radiolabeling of ginkgolide B with 18F
Authors: Suehiro Makiko , Simpson Norman R. , van Heertum Ronald
Published: June 2004

Ginkgolide B, a terpene trilactone constituent of Gingko biloba extracts and an antagonist for the platelet activating factor (PAF) receptor, was radiolabeled with the positron emitter 18F for visualizing its in vivo behavior using positron emission tomography (PET). The 7‐[18F]fluoro analog of ginkgolide B (7‐18FGB) was synthesized via nucleophilic displacement of the triflate group at C7 with [18F]fluoride. The reaction was complete in 5–10 min, affording 7‐18FGB in an average radiochemical yield of approximately 16% (decay corrected). The average specific activity at E.O.S. was approximately 40 GBq/µmol, and the radiochemical and chemical purity was greater than 95%. Copyright © 2004 John Wiley & Sons, Ltd.
Phase Transitions in UHMWPE Fiber Compacts Studied by in situ Synchrotron Microbeam WAXS
Authors: Ratner Stanislav , Weinberg Amotz , Wachtel Ellen , Moret P. Mona , Marom Gad
Published: June 2004

Summary: The temperature dependence of the structure of either cross‐linked or non‐cross‐linked ultra‐high‐molecular‐weight polyethylene (UHMWPE) fiber compacts was studied by synchrotron microbeam wide‐angle X‐ray scattering (WAXS), focusing on the fiber‐fiber interface. The phase transition sequence is: melting of the monoclinic phase in the fiber skin, which was completed by 135 °C; melting of the unconstrained orthorhombic phase, by 152 °C; melting of the constrained orthorhombic phase and a orthorhombic‐hexagonal phase transition until 157 °C; and gradual melting of the hexagonal phase, up to 165 °C. Cross‐linking provides additional thermal stabilization.

Histograms of the azimuthally averaged X‐ray intensity as a function of temperature for cross‐linked ultra‐high‐molecular‐weight polyethylene fiber compacts molded at 145 °C.

image

Histograms of the azimuthally averaged X‐ray intensity as a function of temperature for cross‐linked ultra‐high‐molecular‐weight polyethylene fiber compacts molded at 145 °C.
The Aspect Ratio and Gas Permeation in Polymer‐Layered Silicate Nanocomposites
Authors: Osman Maged A. , Mittal Vikas , Lusti Hans Rudolf
Published: June 2004

Summary: Organophilized montmorillonite‐epoxy and ‐polyurethane nanocomposites, useful for packaging applications, were prepared and their oxygen permeability was measured. The composite morphology was mixed, exfoliated and intercalated, as shown by wide‐angle X‐ray diffraction (WAXRD) and transmission electron microscopy (TEM). The gas‐barrier performance of the polyurethane composites was better than that of the epoxy composites due to more exfoliation. The average aspect ratio of the montmorillonite platelets in the nanocomposites could be estimated from the reduction in permeability by a numerical finite element approach.

A computer model comprising 50 randomly distributed and oriented round platelets with an aspect ratio of 50 at 3 vol.‐% loading, periodic boundary conditions applied.

image

A computer model comprising 50 randomly distributed and oriented round platelets with an aspect ratio of 50 at 3 vol.‐% loading, periodic boundary conditions applied.
Kindt's paper epitomizes the problems in gambling research
Authors: Walker Douglas M.
Published: June 2004

For many readers, the casino gambling issue of Managerial and Decision Economics1 will be their first exposure to economic research on casino gambling. Based solely on a reading of the MDE issue, one might get the impression there is overwhelming evidence that legal casino gambling is ‘bad.’ But readers should be skeptical of what they read, as there is no such consensus in the literature. Indeed, the literature is fraught with methodological problems and inconsistencies. Professor Kindt's article (2001), in particular,2 exemplifies some of the problems that have been plaguing gambling research since the mid‐1990s. Ordinarily, a reaction to an article like Kindt's would be unwarranted, since many of his arguments are supported only by newspaper articles. However, it is perhaps worthwhile to point out a few of the problems with Kindt's work, and with gambling research in general, so that research can advance, instead of digressing, as it has with the publication of the special issue of MDE. My comments focus on three issues in Kindt's paper. Copyright © 2004 John Wiley & Sons, Ltd.
Winning at craps: Are casinos vulnerable to state suits for social costs?—A preliminary analysis
Authors: Vandall Frank J.
Published: June 2004

Assume that Lucky has flown to the state of Nitro from his home state of Peach intending to gamble and lose perhaps two to three hundred dollars but instead has lost $50,000. This triggers the loss of his car, house, job, and eventually his wife. What issues are involved for the state of Peach? Copyright © 2004 John Wiley & Sons, Ltd.
A brief discussion on the different formulations of the coupled mode method in chiral media: Application to the parallel‐plate chirowaveguide
Authors: Gómez A. , Vegas A. , Solano M. A.
Published: June 2004

The application of the coupled‐mode method (CMM) for calculating the propagation constants and the electromagnetic‐field distribution in chirowaveguides is well known. In this paper, two different formulations of the method are revised and compared, and are then extended to partially filled parallel‐plate waveguides. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 42: 181–185, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20245
Novel compact narrowband CPW bandpass filter using an efficient loaded structure
Authors: Liao Shry‐Sann , Chen Hsien‐Ku , Liao Hsien‐Yuan , Chang Yin‐Cheng
Published: June 2004

A novel compact narrowband bandpass filter (BPF) using coplanar waveguide (CPW) with an efficient slow‐wave structure is presented. The folded open stub is used as loaded structure for the filter design with the merit of better slow‐wave factor. Additionally, this filter achieves a sharp transition band (TB) and 5% bandwidth at 2.4 GHz with 60.67% reduced factor. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 42: 185–187, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20246
Mutual impedance between two dipole antennas fed by single source
Authors: Amin M. , Cahill R.
Published: June 2004

We present a new circuit‐model approach which can be used to compute the mutual impedance between two dipoles fed at the same feed point. The validity of the method is confirmed by comparison with mutual impedance values obtained when the dipoles are individually excited and orientated at angles between 0° and 90°. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 42: 187–189, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20247
Inverted L‐shaped and parasitically coupled inverted L‐shaped microstrip patch antennas for wide bandwidth
Authors: Neog D. K. , Pattnaik S. S. , Dutta M. , Devi S. , Khuntia B. , Panda D. C.
Published: June 2004

Coax‐fed inverted L‐shaped microstrip antennas and parasitically coupled inverted L‐microstrip antennas are presented. The inverted L‐shaped microstrip antenna gives an impedance bandwidth of 30.6%, which is increased to 33.7% by parasitic coupling. The bandwidth has been achieved with a substrate thickness of 2 mm. Radiation patterns and gains are also studied and presented. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 42: 190–192, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20248
32‐channel arrayed‐waveguide‐grating multiplexer using fluorinated polymers with high thermal stability
Authors: Wang Fei , Ma Chunsheng , Sun Wei , Li Aize , Zhao Yu , Zhang Haiming , Jiang Zhenhua , Zhang Daming
Published: June 2004

A 32‐channel arrayed‐waveguide‐grating (AWG) multiplexer operating around 1550 nm has been designed and fabricated using synthesized cross‐linkable fluorinated poly (ether ether ketone). The channel spacing is 0.8 nm (100 GHz). The insertion loss of the multiplexer is 12–17 dB and the cross talk is less than −20 dB. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 42: 192–196, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20249
Numerical design for efficiently coupling conventional and photonic‐crystal waveguides
Authors: Chietera G. , Bouk A. H. , Poletti F. , Poli F. , Selleri S. , Cucinotta A.
Published: June 2004

Different tapered‐waveguide junctions are investigated for coupling light between traditional dielectric and photonic‐crystal waveguides characterized by a triangular lattice of air holes. Efficient approaches for the taper design, which allow flat‐transmission efficiency higher than 85% in the whole spectrum of the third telecommunication window, are proposed. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 42: 196–199, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20250
10‐GB/S transmission over 1400 km on G.652 fiber with dispersion compensation by chirped FBG
Authors: Tan Zhongwei , Jian Shuisheng , Liu Yan , Ning Tigang
Published: June 2004

We successfully transmit a signal as long as 1400 km with G.652 fiber using chirped fiber gratings. Asymmetrical apodization is adopted to reduce the grating's group‐delay ripple (GDR). Power and dispersion management are used to suppress nonlinear effects. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 42: 199–201, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20251
A focused‐beam methodology for measuring microwave backscatter
Authors: Schultz John W. , Hopkins Edward J. , Maloney James G. , Kuster Eric J. , Kesler Morris P.
Published: June 2004

A methodology is developed to determine the microwave backscatter from inhomogeneous materials and structures using a free‐space focused‐beam apparatus. This quantitative method determines the scattering coefficient for inhomogeneous surfaces and echo width for linear discontinuities. Measured data from a random rough surface are compared to compact radar cross‐section (RCS) range measurements, scatter data from a periodic array are compared to numerical simulations, and edge‐diffraction measurements are compared to model calculations. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 42: 201–205, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20252
Experimental investigation of novel multifingered antenna
Authors: Ooi B. L. , Leong M. S. , Yu K. Y. , Wang Y. , Chen B.
Published: June 2004

A novel tri‐band, multifingered antenna is proposed. With the integration of the electromagnetic bandgap as an impedance‐matching element, a wider impedance bandwidth response is obtained. The proposed antenna is also noted to be smaller in size, as compared to the conventional microstripfed tri‐band antenna. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 42: 206–208, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20253
Characterization of benzocyclobutene optical waveguides fabricated by electron‐beam direct writing
Authors: Hsu Chih‐Wei , Chen Hsuen‐Li , Chao Wen‐Chi , Wang Way‐Seen
Published: June 2004

Optical waveguides based on benzocyclobutene polymer are fabricated by electron‐beam direct writing without etching. The propagation losses of waveguide measured at 1.55 μm for both TE and TM polarizations are 0.76 and 0.86 dB/cm, respectively. Moreover, the characteristics of waveguide bends are discussed for comparison. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 42: 208–210, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20254
W‐band transmitter module using gallium arsenide mmics
Authors: Archer John W. , Shen Mei Gan
Published: June 2004

This paper describes a high‐gain, single‐sideband, upconverting transmitter module developed for point‐to‐point telecommunications in the 83–87‐GHz band. Four gallium arsenide (GaAs) monolithic microwave integrated circuits (MMICs), which can readily be fabricated using standard commercial processes, are used in the multichip module. The transmitter exhibits a typical lower‐sideband up‐conversion gain of 20 dB and a typical output power of +5 dBm (at −1‐dB gain compression) between 83 and 87 GHz. Suppression of the higher sideband is greater than −15 dB. The two‐tone, 3rd‐order intercept point is typically +15 dBm for a tone spacing of 100 MHz at the lower sideband IF input. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 42: 210–213, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20255
Integral‐equation‐based analysis of transient scattering from surfaces with an impedance boundary condition
Authors: Chen Qin , Lu Mingyu , Michielssen Eric
Published: June 2004

A marching‐on‐in‐time (MOT)‐based scheme for the analysis of transient scattering from closed surfaces characterized by an impedance boundary condition (IBC) is described. The time‐domain integral equations being solved involve no analytical approximation and are free of spurious solutions. The proposed scheme is validated by a host of numerical examples. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 42: 213–220, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20256
An LTCC planar ultra‐wideband antenna
Authors: Ying Chen , Li G. Y. , Zhang Y. P.
Published: June 2004

An ultra‐wideband (UWB) planar volcano‐smoke slot antenna realized using low‐temperature cofired ceramic (LTCC) technology is reported in this paper. The antenna, developed for a single‐package solution of UWB radio, hasimple single‐layer structure and a small footprint of 23 × 23 mm2. The result shows that the prototype antenna achieves an impedance bandwidth of 9 GHz (with return lossS11< −10 dB from 3 to 12 GHz). The antenna radiation pattern at frequencies 3.5, 6.85, and 10.1 GHz and gain versus frequency are also presented. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 42: 220–222, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20257
Wideband bow‐tie antenna with coplanar stripline feed
Authors: Bindu G. , Hamsakkutty V. , Lonappan Anil , Jacob Joe , Thomas Vinu , Aanandan C. K. , Mathew K. T.
Published: June 2004

The experimental investigation on a coplanar stripline‐fed bow‐tie antenna backed by an image plane is presented. Analysis of the radiation characteristics shows that the antenna exhibits an enhanced 2:1 SWR bandwidth of 46%, low cross polarization, and reduced back radiation. This antenna has applications in confocal microwave imaging and impulse ground‐penetrating radar. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 42: 222–224, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20258
Mutual coupling between planar inverted‐F antennas
Authors: Carrasco H. , Hristov H. D. , Feick R. , Cofré D.
Published: June 2004

Mutual coupling between two planar inverted‐F antennas (PIFAs) based on a ground plane is studied numerically and experimentally. Several arrangements of collinear, orthogonal, and parallel PIFA elements with interelement spacing ranging from 0.1λ to 0.9λ are examined at the design frequency of 2.45 GHz, and in the 2.0–3.0‐GHz frequency band. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 42: 224–227, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20259
Encryption‐selectable holographic storage in LiNbO3 with angle multiplexing
Authors: Su Wei‐Chia , Sun Ching‐Cherng , Su Wei‐Chen
Published: June 2004

An encryption‐selectable holographic storage algorithm in LiNbO3 using angular multiplexing is proposed and demonstrated. It offers more flexibility to encrypt or not encrypt the data (optionally) during the recording processes. The functions encryption and nonencryption storage are alternately handled by a random‐phase pattern and a uniform‐phase pattern. The random phase pattern is also used to decrypt the encrypted information. The experimental results obtained using a ground glass to realize the proposed method are presented. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 42: 227–230, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20260
Multiband miniaturized PIFA for compact wireless‐communication applications
Authors: Elsadek Hala , Nashaat Dalia , Ghali Hani
Published: June 2004

The definitive element of any wireless device is its antenna. In this paper, a multiband planar inverted‐F antenna (PIFA) is miniaturized. The results show that a 68%–82% size reduction can be achieved. Two techniques for reduction are utilized: (i) adding lumped load and (ii) miniaturizing the geometry by using the fractal concept. New PIFA configurations are reached. Quad‐band operation is achieved. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 42: 230–234, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20261
Color face‐image recognition with liquid‐crystal spatial light modulators
Authors: Chen Chihung , Chen Chulung , Lee Chung‐Cheng , Chen Chiwen
Published: June 2004

In this paper, for color face‐image recognition, we adopt a system based on the nonzero‐order joint‐transform correlator and use the method of Lagrange multipliers to design the reference functions. Some different facial expressions are utilized as test images to study the discrimination capability. Additionally, random noise is added to the test images in order to investigate the effectiveness of the proposed technique. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 42: 234–237, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20262
Effects of time‐division multiplexing of two‐pump wavelengths on a counter‐pumped Raman‐fiber amplifier
Authors: Mahdi Mohd Adzir , Sheih Shou‐Jong
Published: June 2004

We demonstrate the impacts of the time‐division multiplexing (TDM) technique on a two‐pump wavelength Raman‐fiber amplifier. Modulation frequency is critical in this pumping technique, which can create temporal gain variations at low frequencies. The effective noise figure also degrades when utilizing this pumping scheme due to the arising of amplified spontaneous emission. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 42: 238–239, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20263
Analysis of negative‐resistance characteristics in active capacitance circuit
Authors: Chun Young‐Hoon , Lee Jae‐Ryong , Yun Sang‐Won , Rhee Jin‐Koo
Published: June 2004

An active‐capacitance circuit with a series‐feedback network is analyzed in depth and its application to an active microwave band‐pass filter (BPF) is discussed. In this paper, we extract the exact equivalent values of this circuit and analyze the RF characteristics while varying the values of active devices and feedback circuits. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 42: 240–243, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20264
Broadband low‐profile printed T‐shaped monopole antenna for 5‐GHz wlan operation
Authors: Su Saou‐Wen , Wong Kin‐Lu , Chen Hong‐Twu
Published: June 2004

A broadband low‐profile printed T‐shaped monopole antenna is presented. It is demonstrated that, by short‐circuiting the central arm of a low‐profile T‐shaped monopole to the ground plane, much improved impedance matching over a wide frequency range can be achieved. A constructed prototype showing a low profile of only 3 mm and a wide bandwidth larger than 1.1 GHz covering the 5.2/5.8‐GHz WLAN bands is presented. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 42: 243–245, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20265
Simultaneous WDM channel wavelength monitoring using a temperature‐modulated AWG
Authors: Kim Sang‐Yuep , Namgung Seong‐Won , Lee Jae‐Seung
Published: June 2004

We propose a method to monitor the center wavelengths of wavelength‐division multiplexed optical channels simultaneously using a temperature‐modulated arrayed waveguide grating (AWG). With this method, we can reduce the cost by using standard AWGs. Also, monitoring errors can be greatly suppressed in the presence of amplified‐spontaneous‐emission noises. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 42: 245–249, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20266
Dual‐band printed dipole antenna array for an emergency rescue system based on cellular‐phone localization
Authors: Villemaud G. , Decroze C. , Dall'omo C. , Monediere T. , Jecko B.
Published: June 2004

This paper describes the study of a novel dual‐band antenna dedicated to be mounted on a helicopter for emergency localisation of cellular phones within the framework of the RNRT project called LUTECE. A folded dipole placed on a limited ground plane to allow wideband functionality and good radiation characteristics is proposed. Starting from this new topology, a directive array for the emission part and a circular disposition of five radiating elements with separated outputs for the receiving part are studied. All these developments are performed using our simulation code (FDTD method) along with experimental studies. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 42: 249–253, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20267
A novel interleaver based on dual‐pass Mach‐Zehnder interferometer
Authors: Zhang Ting , Chen Kai , Sheng Qiuqin
Published: June 2004

A novel interleaver based on a dual‐pass Mach–Zehnder (M–Z) interferometer is proposed and analyzed by both theory and experiment. Compared with the traditional M–Z interferometer, the isolation of the new structure is enhanced greatly. When the frequency spacing reaches 50 GHz, its isolation is more than 25 dB. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 42: 253–255, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20268
A novel LTCC power combiner
Authors: Ooi B. L. , Xu D. X. , Wang Y. , Chen B. , Leong M. S.
Published: June 2004

A novel LTCC power combiner, which is adopted from conventional balun design, is presented. In contrast to the conventional balun network, our design provides one pair of nondifferential signals with minimum phase difference between the outputs. Experimental results are given in the paper to verify our theoretical analysis and design. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 42: 255–257, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20269
Robust knowledge‐based neural‐network model for microstrip T‐junction structure
Authors: Hong Jingsong , Wang Bing‐Zhong
Published: June 2004

In this paper, a robust knowledge‐based neural‐network model (RKBNN), whose neurons in the hidden layer are all knowledge‐based neurons instead of conventional neurons, is proposed for the microstrip T‐junction structure. The RKBNN model is electromagnetically developed with a set of data that are produced using the method of moments (MoM) method. Through numerical experiments, many advantages have been shown by the RKBNN model over the conventional multilayer perceptron model. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 42: 257–260, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20270
Experimental implementation of a wideband high‐gain 8‐array slot antenna for mobile communications
Authors: Jang Yong‐Woong
Published: June 2004

The experimental implementation of a T‐shaped microstrip‐fed printed 8‐element slot‐array antenna is presented in this paper. Although the use of a high relative permittivity (εr= 4.3) substrate usually restricts the operation bandwidth, the radiation resistance also has a low value. The dependence of design parametersld, offset on the bandwidth characteristics is investigated. The measured bandwidth of the 8‐array slot array antenna is 1.3933 to 2.5989 GHz, which is approximately 60.3% for theS11≤ −10 dB. The obtained 10‐dB return‐loss impedance bandwidth covers the DCS (1.71–1.88 GHz), PCS (1.85–1.99 GHz), IMT‐2000 (1.90–2.20 GHz), UMTS (1.92–2.17 GHz), WLL (2.40–2.48 GHz) bands. The measured peak gain of the 8‐array slot‐array antenna in the usable frequency band is more than approximately 10.5 dBi. This antenna is an attractive candidate for wireless, satellite, and mobile communications applications. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 42: 260–262, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20271