bluuebunny/crossref_metadata_2025_split huggingface dataset:
A low‐cost surface‐mount monopole antenna for 2.4/5.2/5.8‐GHz band operation
Authors: Su Saou‐Wen , Fang Shyh‐Tirng , Wong Kin‐Lu 
Published: February 2003

AbstractA low‐cost surface‐mount monopole antenna obtained by folding a metallic strip onto a low‐profile square‐disk foam base is presented. With a compact size of 10 × 10 × 2 mm3, the antenna can generate two separate wide resonant modes, with the lower mode covering the 2.4‐GHz WLAN band (2400–2484 MHz), and the upper mode covering both of the 5.2‐GHz HIPERLAN band (5150–5350 MHz) and the 5.8‐GHz ISM band (5725–5875 MHz). Good measured antenna gain for operating frequencies across the 2.4/5.2/5.8‐GHz bands is also obtained. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 36: 487–489, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10798
Design of the optical label eraser for DWDM network systems
Authors: Zhang Yejin , Zhu Lin , Gao Zhiguo , Chen Minghua , Xie Shizhong 
Published: February 2003

AbstractIn this paper, an all‐fiber birefringent filter was designed by using the Sagnac interferometer. The frequency spacing of the filter transfer function's two adjacent notches alternates between two different periods, which differs from the normal fiber loop mirror (FLM) and Lyot–Sagnac filters. A filter with over 40‐dB notch depth can be used as an optical label eraser in N × 20 Gb/s WDM all‐optical label swapping (AOLS) networks with 50‐GHz channel spacing. The results show that the filter is a high‐performance optical label eraser, and this work presents an approach for optical label erasing in high‐speed WDM AOS networks with narrow channel spacing. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 36: 489–491, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10799
Effects of finite‐sized groundplane on radiation pattern deformation, impedance bandwidth, and radiation efficiency of U‐PIFA
Authors: Salonen Pekka 
Published: February 2003

AbstractPlanar‐inverted F antennas (PIFAs) are widely used in portable devices, which are definitely size‐limited. Therefore, it is useful to study the effects of a finite‐sized ground plane on the antenna's various radiation and circuit parameters. In this paper, impedance bandwidth with criterion VSWR < 2 and radiation efficiency as a function of antenna position on a finite‐sized ground plane are studied for a dual‐band U‐shaped‐slot PIFA (U‐PIFA). Impedance bandwidth and radiation efficiency dependence along the ground plane are the main concerns. The results show that radiation efficiency and impedance bandwidth are strongly dependent on the antenna position on the groundplane. In addition, it is shown that the desired bandwidth can be controlled by proper location of the antenna. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 36: 491–496, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10800
BER performance comparison between an active Mach‐Zehnder modulator and passive Mach‐Zehnder interferometer for conversion of microwave subcarriers of BPSK signals
Authors: Le Guennec Y. , Maury G. , Cabon B. 
Published: February 2003

AbstractThe BER performances of a classical external optical Mach–Zehnder modulator and a passive all‐optical integrated device, an unbalanced Mach–Zehnder interferometer, are measured and analyzed theoretically. This analysis show better results for the passive all‐optical device than for the external modulator in the case of the laser diode's high enhancement factor. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 36: 496–498, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10801
Bandwidth enhancement of U‐slot patch antenna on high permittivity ceramic substrate for Bluetooth application
Authors: Tzou Wen‐Cheng , Chen Hua‐Ming , Chen Ying‐Chung , Yang Cheng‐Fu 
Published: February 2003

AbstractA patch antenna on a very high‐permittivity ceramic substrate with a pair of U‐shaped slots is investigated experimentally at 2.45 GHz. The dielectric constant of the ceramic substrate is 43. By embedding a pair of U‐shaped slots close to the nonradiating edges of the patch, two adjacent resonant modes are very close to each other and are both covered. Thus, an enhanced impedance bandwidth of 5.3% can be achieved. The proposed antenna operates with 2:1 VSWR throughout the entire Bluetooth band (2400–2484 MHz). Details of the antenna design and experimental results are presented. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 36: 499–501, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10802
Reflection L‐band erbium‐doped fiber‐amplifier‐based on a fiber‐loop mirror
Authors: Meng Hongyun , Liu Yange , Gao Weiqing , Zhang Hao , Yuan Shuzhong , Dong Xiaoyi 
Published: February 2003

AbstractA novel reflection L‐band erbium‐doped fiber amplifier, based on a fiber loop mirror, is constructed. This amplifier reflects the backward ASE to the EDF as a secondary pumping source. A gain of 30 dB (an increase of 6 dB) is obtained, compared to the forward‐end‐pumped EDFA in the range of 1570–1603 nm. The saturated output power was 7.63 dBm and 7.6 dBm for 1580 nm and 1600 nm signals, with increases of 2.98 dB and 3 dB, respectively, compared to the forward end‐pumped EDFA. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 36: 501–503, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10803
Germ cell transplantation in goats
Authors: Honaramooz Ali , Behboodi Esmail , Blash Stephen , Megee Susan O. , Dobrinski Ina 
Published: February 2003

AbstractTransplantation of spermatogonial stem cells provides a unique approach for the study of spermatogenesis and manipulation of the male germ line. This technique may also offer an alternative to the currently inefficient methods of producing transgenic domestic animals. We have recently established the technique of spermatogonial transplantation, originally developed in laboratory rodents, in pigs, and this study was aimed to extend the technique to the goat. Isolated donor testis cells were infused into the seminiferous tubules of anesthetized recipient goats through an ultrasonographically‐guided catheter inserted into the rete testis. Donor cells were obtained by enzymatic digestion of freshly collected testes from immature goats (either from the recipients' contralateral testis or from unrelated donors). Prior to transplantation, testis cells were labeled with a fluorescent marker to allow identification after transplantation. Recipient testes were examined for the presence and localization of labeled donor cells at 3‐week intervals up to 12 weeks after transplantation. Labeled donor cells were found in the seminiferous tubules of all testes, comprising 10–35% of the examined tubules. Histological examination of the recipient testes did not reveal evident tissue damage, except for limited fibrotic changes at the site of needle insertion. Likewise there were no detectable local or systemic signs of immunologic reactions to the transplantations. These results indicate that germ cell transplantation is technically feasible in immature male goats and that donor‐derived cells are retained in the recipient testis for at least three months and through puberty. This study represents the first report of germ cell transplantation in goats. Mol. Reprod. Dev. 64: 422–428, 2003. © 2003 Wiley‐Liss, Inc.
Over‐expression and secretion of angiogenin in intrauterine growth retardation placenta
Authors: Rajashekhar G. , Loganath A. , Roy A.C. , Wong Y.C. 
Published: February 2003

AbstractHuman angiogenin is a potent inducer of neovascularization. There is a strong evidence to suggest that it might be involved in morphological and angiogenic changes in the placenta, that are necessary for a successful fetal outcome during pregnancy. However, its precise role in the pathogenesis of abnormal pregnancies is yet unknown. Intrauterine growth retardation (IUGR), an abnormal pregnancy is not a specific disease entity per se, but rather a manifestation of many possible fetal and maternal disorders. In this study, we demonstrated, for the first time, that placental explants in vitro secrete significantly elevated levels of angiogenin in placental tissues from patients with IUGR. We also observed enhanced mRNA expression in placenta from these patients. In addition, using the immunohistochemical methods, we observed identical staining of angiogenin to villous syncytiotrophobalst and fetal endothelial cells in both IUGR and normal placenta. Functionally active placental explants were used to detect immunoreactive angiogenin in conditioned media of all the samples from IUGR placenta and normal term group. The mean levels of angiogenin secreted by IUGR placenta were 1.4‐, 1.6‐, and 1.3‐fold higher (P < 0.01) than normal term samples at 24, 48, and 72 hr of culture, respectively. Expression profiles of angiogenin from term and IUGR cases are in agreement with its mRNA levels and immunoblot analysis. In conclusion, the significant elevated levels of angiogenin in IUGR placenta may provide a molecular mechanism for the abnormal placental development. Mol. Reprod. Dev. 64: 397–404, 2003. © 2003 Wiley‐Liss, Inc.
Meiosis in male PL/J mice: A genetic model for gametic aneuploidy
Authors: Pyle April , Handel Mary Ann 
Published: February 2003

AbstractSperm from mice of the PL/J strain have a high frequency of sperm‐head morphology abnormalities. Fluorescence in situ hybridization (FISH) methods revealed that PL/J sperm are also characterized by a high frequency of aneuploidy. The traits of abnormal sperm head morphology and aneuploidy are associated with numerous meiotic abnormalities. Spermatocytes of PL/J mice exhibit chromosome asynapsis during meiotic prophase as well as reduced crossing over, revealed by analysis of both MLH1 foci in pachytene spermatocytes and chiasmata seen at the first meiotic metaphase. During the first meiotic division, roughly one‐third of the PL/J spermatocytes exhibit aberrant spindle morphology, with abnormalities including monopolar spindles, split spindle poles, and incomplete spindle formation and centrosomal abnormalities. F1 progeny of a cross between PL/J and C57BL/6J did not exhibit a high frequency of either sperm aneuploidy or sperm head morphology aberrations, as would be expected if the PL/J traits were dominant. Among progeny of a backcross of F1 mice to PL/J, none of 16 males assessed exhibited elevated frequencies of sperm head morphology abnormalities. Four of the individuals exhibited elevated sperm aneuploidy, but not at the levels of the PL/J parents. Thus, it is likely that the aberrant PL/J traits are due to several genes and/or modifiers affecting the generation of both sperm aneuploidy and abnormal sperm head morphology. Mol. Reprod. Dev. 64: 471–481, 2003. © 2003 Wiley‐Liss, Inc.
Chromatin configuration and transcriptional control in human and mouse oocytes
Authors: Miyara Faïçal , Migne Carole , Dumont‐Hassan Martine , Meur Alain Le , Cohen‐Bacrie Paul , Aubriot François‐Xavier , Glissant Amélie , Nathan Catherine , Douard Stéphane , Stanovici Alexandre , Debey Pascale 
Published: February 2003

AbstractIn vitro maturation of human oocytes at the germinal vesicle (GV) stage could offer an alternative in several cases of female infertility. It however rests on a better knowledge of the quality of human oocyte. Using fluorescence imaging of DNA and of the transcription sites, combined with electron microscopy, we show that human oocytes follow size‐dependent changes in chromatin configuration, transcription sites distribution and nuclear ultrastructure that follow those observed in mouse GV oocytes. We thus analyzed in mouse GV oocytes the phosphorylation dependence of the transcriptional activity. We show by Western blot that, while active GV oocytes have approximately the same proportion of hypo‐ and hyperphosphorylated forms of the RNA polymerase II (RNAP II), the hyperphosphorylated form is almost absent from inactive oocytes. We also show that (1) RNAP II‐dependent transcription is much less sensitive to various kinase inhibitors in mouse oocytes than in somatic cells or mouse one‐cell embryos, although the phosphorylation equilibrium of RNAP II was largely shifted towards the hypo‐phosphorylated form upon treatment with these inhibitors (2) RNAP I is completely insensitive to kinase inhibitors in GV oocytes. Mol. Reprod. Dev. 64: 458–470, 2003. © 2003 Wiley‐Liss, Inc.
ADAM7 (a disintegrin and metalloprotease 7) mRNA is suppressed in mouse epididymis by neonatal exposure to Diethylstilbestrol
Authors: Adachi Tetsuya , Matsuno Yoshiharu , Sugimura Atsushi , Takano Kaiya , Koh Kyu‐Bom , Sakurai Kenichi , Shibayama Takako , Iguchi Taisen , Mori Chisato , Komiyama Masatoshi 
Published: February 2003

AbstractWe investigated whether neonatal exposure to diethylstilbestrol (DES) induces the alteration of mRNA expression in adult mouse epididymis, which plays an important role in sperm maturation. Using a cDNA subtraction method, we isolated 15 changed gene clones in neonatally DES‐treated mouse epididymides, and we found a clone homologous with a disintegrin and metalloprotease (ADAM) 7 in the epididymis, as a suppressed gene, by means of neonatal DES treatment in 8‐week‐old mice. Indeed, it was confirmed by Northern blot analysis that the ADAM7 mRNA expression in the epididymis was at a lower level in neonatally DES‐treated mice than in non‐treated mice. Moreover, in situ hybridization analysis and real‐time reverse transcription and polymerase chain reaction (real‐time RT‐PCR) revealed that ADAM7 expression was markedly reduced in the corpus region of the epididymis of DES‐treated mice as compared with non‐treated mice. Our results suggest that neonatal exposure to DES leads to the suppression of ADAM7 expression in the epididymis in the long term. ADAM7 gene expression might be a biological marker of fetal or neonatal exposure to estrogenic compounds, including endocrine disruptors. Mol. Reprod. Dev. 64: 414–421, 2003. © 2003 Wiley‐Liss, Inc.
Increased recombination frequency showing evidence of loss of interference is associated with abnormal testicular histopathology
Authors: Varmuza Susannah , Ling Ling 
Published: February 2003

AbstractNondisjunction leading to aneuploid gametes has been linked genetically to both increases and decreases in recombination frequency on the aneuploid chromosome. In the present study, we present physical evidence of increased frequency of recombination nodules as measured by Mut‐S‐like homologue‐1 (MLH1) foci on pachytene chromosomes from sterile male mice homozygous for a mutation in the protein phosphatase 1cγ (PP1cγ) gene. The pattern of elevated recombination frequency in PP1cγ mutant spermatocytes is consistent with a loss of interference. Previous studies demonstrated: (1) spermiogenesis is impaired starting at step 8 with a severe reduction in elongating and condensed spermatids; (2) spermatids and sperm exhibit elevated rates of DNA fragmentation; and (3) haploid gametes exhibit elevated levels of aneuploidy. Morphometric analysis of developing testes revealed that the first wave of meiosis proceeds at a normal rate in mutant testes, a surprising result given that the PP1 inhibitor okadaic acid has been shown to accelerate progression of spermatocytes from pachytene to the first meiotic division (MI). Evidence of abnormal testicular histopathology is apparent at 3 weeks, before the appearance of haploid gametes, eliminating the possibility that the mutant phenotype is caused by the presence of abnormal spermatids, but coincident with the appearance of the first set of mid to late pachytene spermatocytes. These observations lead us to conclude that the PP1cγ mutation causes a complex phenotype, including subtle adverse effects on meiosis, possibly mediated by defective signaling between germ cells and Sertoli cells. Mol. Reprod. Dev. 64: 499–506, 2003. © 2003 Wiley‐Liss, Inc.
Glutathione and adenosine triphosphate content of in vivo and in vitro matured porcine oocytes
Authors: Brad A.M. , Bormann C.L. , Swain J.E. , Durkin R.E. , Johnson A.E. , Clifford A.L. , Krisher R.L. 
Published: February 2003

AbstractGlutathione (GSH) content in mature porcine oocytes is correlated with subsequent fertilization and developmental success. Adenosine triphosphate (ATP) is an important energy source for maintaining cellular activities and protein synthesis. The objective of this study was to compare GSH and ATP concentrations of in vivo and in vitro matured porcine oocytes. Ovulated, in vivo matured oocytes were frozen at −80°C in groups of 10–20 (GSH) or 5–10 (ATP). In vitro oocytes were matured in either tissue culture medium‐199 (TCM199) supplemented with polyvinyl alcohol (PVA) or hyaluronic acid (MAP5), or North Carolina State University‐23 (NCSU23) supplemented with porcine follicular fluid (pFF) and frozen as described, or fertilized and cultured. GSH content was determined by the dithionitrobenzoic acid–glutathione disulfide (DTNB–GSSG) reductase recycling assay. ATP content was determined by using the Bioluminescent Somatic Cell Assay Kit. Oocytes matured in vitro in defined TCM199 with PVA or hyaluronic acid, or NCSU23 with pFF had significantly lower concentrations (P < 0.05) of GSH (n = 207, 9.82 ± 0.71 pmol/oocyte; n = 104, 9.73 ±  0.81 pmol/oocyte; n = 108, 7.89 ± 0.66 pmol/oocyte, respectively) compared to in vivo matured oocytes (n = 217, 36.26 ± 11.00 pmol/oocyte). Concentrations of ATP were not different between treatments (in vivo, n = 70, 0.97 ± 0.07 pmol/oocyte; TCM–PVA, n = 117, 0.81 ± 0.13 pmol/oocyte; TCM–MAP, n = 107, 1.02 ± 0.18 pmol/oocyte; NCSU–pFF, n = 134, 0.71 ± 0.08 pmol/oocyte). Intracellular ATP content does not appear to be related to developmental potential in porcine oocytes. Low intracellular GSH may be responsible, in part, for lower developmental competence observed in in vitro matured porcine oocytes. Mol. Reprod. Dev. 64: 492–498, 2003. © 2003 Wiley‐Liss, Inc.
Stage‐specific regulatory element of mouse Sry gene
Authors: Yokouchi Kou , Ito Masanori , Nishino Koichiro , Yamanouchi Keitaro , Naito Kunihiko , Suzawa Miyuki , Kato Shigeaki , Hakamata Yoji , Endo Hitoshi , Tojo Hideaki 
Published: February 2003

AbstractSry expression is essential for initiating male sex differentiation, and the expression occurs only during a restricted period in the developing gonad. It is thought that Sry is part of a pathway of genes that regulate sex determination. Although the interactions of several genes with Sry expression have been suggested, the exact cascade of gene expression regulating Sry transcription is entirely obscure because there is no available cell line expressing Sry and reflecting an in vivo condition. The present study was carried out to investigate the cis‐acting element of the mouse Sry that responds stage specifically to its expression, in part, using transgenic mice expressing GFP on the Y chromosome. Ten DNA fragments were generated by digesting the 5′ upstream region (positions 5491–8039; 2,549 bp) of mouse Sry with appropriate restriction enzymes. In an electrophoretic mobility assay with these fragments, the region from position 5491 to position 5799 (309 bp) was identified as forming specific protein–DNA complexes with nuclear extracts from 11.5 days post coitus (dpc) gonads, but not from 12.5 and 13.5‐dpc gonads. This region also formed specific protein–DNA complexes with the nuclear extracts from adult testicular germ cells that generate only a circular form from Sry. This stage‐specific responsive region was narrowed down to positions 5559–5616 by DNase I footprinting analysis. The assay of DNase I hypersensitive (HS) using the nuclear lysates from the 11.5‐dpc urogenital ridges demonstrated that the novel HS site was located in the proximity of position 5600. This region DNase I HS was also detected at the same position when the lysates from adult testicular germ cells were applied. The results indicate that the present HS site may be involved in the transcriptional regulation of the linear and/or circular molecule transcripts from mouse Sry gene. Mol. Reprod. Dev. 64: 389–396, 2003. © 2003 Wiley‐Liss, Inc.
Proliferation of donor mitochondrial DNA in nuclear transfer calves (Bos taurus) derived from cumulus cells
Authors: Takeda Kumiko , Akagi Satoshi , Kaneyama Kanako , Kojima Toshiyuki , Takahashi Seiya , Imai Hiroshi , Yamanaka Mariko , Onishi Akira , Hanada Hirofumi 
Published: February 2003

AbstractIn embryos derived by nuclear‐transfer (NT), fusion of donor cell and recipient oocyte caused mitochondrial heteroplasmy. Previous studies from other laboratories have reported either elimination or maintenance of donor‐derived mitochondrial DNA (mtDNA) from somatic cells in cloned animals. Here we examined the distribution of donor mtDNA in NT embryos and calves derived from somatic cells. Donor mitochondria were clearly observed by fluorescence labeling in the cytoplasm of NT embryos immediately after fusion; however, fluorescence diminished to undetectable levels at 24 hr after nuclear transfer. By PCR‐mediated single‐strand conformation polymorphism (PCR–SSCP) analysis, donor mtDNAs were not detected in the NT embryos immediately after fusion (less than 3–4%). In contrast, three of nine NT calves exhibited heteroplasmy with donor cell mtDNA populations ranging from 6 to 40%. These results provide the first evidence of a significant replicative advantage of donor mtDNAs to recipient mtDNAs during the course of embryogenesis in NT calves from somatic cells. Mol. Reprod. Dev. 64: 429–437, 2003. © 2003 Wiley‐Liss, Inc.
Maternal gamma (γ)‐tubulin is involved in microtubule reorganization during bovine fertilization and parthenogenesis
Authors: Shin Mi‐Ra , Kim Nam‐Hyung 
Published: February 2003

AbstractIn this study, γ‐tubulin distribution was determined chronologically in conjunction with microtubule dynamics during bovine fertilization and parthenogenesis. In unfertilized bovine oocytes, γ‐tubulin was identified in the cytoplasm, mainly in the cortex and concentrated in the meiotic spindle. Following sperm penetration, γ‐tubulin in the cytoplasm was recruited by a sperm component. During pronuclear apposition, γ‐tubulin was localized as spots at the spindle poles. γ‐tubulin spots were observed in blastomeres of embryos cleaved in vitro. Following electrical stimulation, γ‐tubulin and microtubule matrix were noted in oocyte cortex. In the late pronuclear stage, considerably less γ‐tubulin and microtubules were detected in the cytoplasm. At the mitotic metaphase of parthenotes, γ‐tubulin was recruited to the condensed chromatin and concentrated in the spindle. The γ‐tubulin spots were not detected until the 8‐cell stage of parthenotes. This suggests that maternal γ‐tubulin is recruited by a sperm component to reconstitute the zygotic centrosome. In the absence of sperm components, the cell cycle‐related assembly of γ‐tubulin organizes microtubule nucleation for positioning the pronucleus and spindle protein of mitotic metaphase during the first cell cycle of bovine parthenotes. Mol. Reprod. Dev. 64: 438–445, 2003. © 2003 Wiley‐Liss, Inc.
Partial pressure dependency of 17O/16O and 18O/16O of molecular oxygen in the mass spectrometer
Authors: Abe Osamu , Yoshida Naohiro 
Published: February 2003

AbstractA method to determine both 17O/16O and 18O/16O ratios for molecular oxygen with high precision by direct introduction into the mass spectrometer without gas separation is presented. Because both 17O/16O and 18O/16O in mixed gases have good linear correlations with their mixing ratios, these isotopic compositions can be determined without a gas‐separation procedure by calibration using prepared standard gases with variable mixed ratios and by monitoring the amounts of fragment ions. Analytical precision for δ17O and δ18O of 45 and 7 per meg, respectively, were obtained. The observed partial pressure dependency of isotopic composition may be caused by isotope fractionation during admission from the ionization chamber into the flight tube of the mass spectrometer. Copyright © 2003 John Wiley & Sons, Ltd.