bluuebunny/crossref_metadata_2025 huggingface dataset:
Reinvestigation of the ultrastructure of spermiogenesis and the spermatozoon of Hymenolepis nana (Cestoda, Cyclophyllidea), parasite of the small intestine of Rattus rattus
Authors: Bâ Cheikh Tidiane , Marchand Bernard
Published: February 2005

Spermiogenesis in Hymenolepsis nana begins with the formation of a differentiation zone. This is limited at the front by arched membranes, is surrounded by cortical microtubules assoicated with 12 crested‐like bodies, and contains a single centriole made up of doublets. The distal centriole gives rise to a flagellum that grows at the same pace as the cortical microtubules. Migration of the nucleus takes place after the formation of the flagellum. It is followed by the separation of the old spermatid from the residual cytoplasm. The mature H. nana spermatozoon is filiform and lacks mitochondria. The axoneme, of the 9 + “1” pattern of the Platyhelminthes, does not reach the extremities of the spermatozoon. The nucleus is electron dense and is in close contact with the axoneme around which it coils in a spiral making an angle of 10° to 15° with the spermatozoon axis. The cortical microtubules follow a 10° to 15° helicoidal path along almost their whole length, except at their posterior extremity, where they are parallel to the spermatozoon axis. H. nana is distinguished by the early development of 12 crested‐like bodies of different lengths and by the existence of a single centriole in the differentiation zone. Such a high number of crested‐like bodies had never previously been reported in a cestode. © 1992 Wiley‐Liss, Inc.
The kinetics of oocyte activation and polar body formation in bovine embryo clones
Authors: Powell R. , Barnes F. L.
Published: February 2005

The kinetics of polar body formation were examined in parthenogenetically activated, in vitro matured and aged bovine oocytes. Subsequently, the presence or absence of polar body formation was determined in bovine embryo clones.

Polar body formation, defined as telophase II, occurred by 1 (13/40, 43%) and 2 h (15/21, 71%) postparthenogenetic activation of metaphase II stage oocytes. Parthenogenetically activated oocytes readily formed pronuclei by 4 h. Some oocytes had chromatin in a highly condensed state at 1, 2, and 4 h postactivation (13/72, 18%). These oocytes often (10/13, 77%) appeared to be “self‐enucleated,” as the condensed chromatin was found in a membrane‐bound extrusion. The phenomenon was most prevalent when oocytes were handled at room temperature (25–27°C).

Nuclear transfer procedures were established to bring about synchronous blastomere fusion and oocyte activation conditions. Synchronous conditions were achieved only when oocytes were handled and manipulated at 37–39°C. Embryo clones examined 2 h postfusion did not from a polar body. Conversely, nucleate demi‐oocyte controls were at the late telophase II stage of meiosis. The results are discussed in relation to cell cycle effects on bovine nuclear transfer. © 1992 Wiley‐Liss, Inc.
Cauda epididymal sperm interactions with seminal vesicle fluid
Authors: Curry Patrick T. , Atherton Robert W.
Published: February 2005

The interaction of rat cauda epididymal sperm cAMP‐dependent protein kinase (PKA) with seminal vesicle fluid (SVF) proteins was examined. Specific proteins in SVF act as substrates for the sperm cell PKA. The apparent molecular weights of these proteins are 45.0, 31.5, 17.2, 14.7, and 13.3 kDa. The phosphorylation of one low‐molecular‐weight cauda sperm protein is blocked in the presence of SVF. There is no PKA enzyme activity in SVF. The presence of phosphate transfer activity between the sperm cell enzyme and the SVF proteins is species dependent. For example, mouse and rat SVF proteins are efficient phosphate acceptors, but there is no phosphorylation activity when hamster SVF is used as the enzyme substrate. The sperm cell samples were also assessed for membrane integrity. Specifically, cauda sperm cells used in these assays were judged to be intact when examined microscopically using the fluorescent vital dye carboxyfluorodiacetate. Although there was enzyme activity in the supermatants of the rat sperm cell samples, in the protein kinase assay it required three times as much supernatant volume (compared with intact cell sample volume) to measure the activity. Supernatant enzyme activity did not increase with washing, indicating that the cells were not damaged by this procedure. The enzyme itself does not adhere to the sperm cells, so the PKA enzyme activity is most likely oriented on the external surface of the sperm cell. © 1992 Wiley‐Liss, Inc.
Secretion of bovine α‐lactalbumin into the milk of transgenic rats
Authors: Hochi Shin‐Ichi , Ninomiya Takashi , Waga‐Homma Miho , Sagara Junko , Yuki Atsushi
Published: February 2005

Bovine α‐lactalbumin (bβLA) gene prepared by polymerase chain reaction was introduced into rat genomes by microinjection. Out of 17 transgenic rat lines, 11 secreted bαLA into their milk at concentrations higher than 0.2 μg/ml. Of these, three lines secreted bαLA at concentrations higher than those in bovine milk. The highest concentration of bαĹ secreted into rat milk was 2,400 μg/ml. © 1992 Wiley‐Liss, Inc.
Porcine oocyte zona pellucida Mr 55,000 glycoproteins: Identification of O‐glycosylated domains
Authors: Yurewicz Edward C. , Pack Beverley A. , Sacco Anthony G.
Published: February 2005

The distribution of O‐linked oligosaccharides on the Mr 55,000 glycoproteins, ZP3α and ZP3, of the porcine oocyte zona pellucida was examined. Purified preparations of endo‐β‐galactosidase digested ZP3α and ZP3β were reduced and carboxamidomethylated and digested with trypsin. When the trypsin digests were mapped by HPLC, each glycoprotein yielded only one N‐acetylgalactosamine containing glycopeptide. Purification of the O‐glycopeptides was achieved by a two‐step protocol. Tryptic digests were applied to jacalin‐agarose and specifically‐bound O‐glycopeptides (αOGP and βOGP) were eluted with buffer containing 50 mM α‐methylgalactoside as the haptenic sugar. Further purification of each O‐glycopeptide was accomplished by reverse phase HPLC. Purified O‐glycopeptides were characterized with respect to amino acid and carbohydrate compositions and sequenced by automated Edman degradation; αOGP was a 41‐residue glycopeptide with three O‐linked sugar chains. Sequence comparisons revealed a 75% identity between αOGP and a corresponding segment of rabbit rec55 zona protein; OGP was a 25‐residue glycopeptide characterized by the presence of one N‐linked and five O‐linked sugar chains and a trypsin‐resistant internal arginine residue. Sequence alignments revealed an 80% or greater identity between βOGP and internal peptides of mouse, hamster and human ZP3 zona proteins. These studies demonstrate that in the case of ZP3α and ZP3β, the pig homologues of rabbit rec55 and mouse ZP3, respectively, O‐linked oligosaccharides are confined within delimited domains rather than widely dispersed on the polypeptide backbone. Such clustering of O‐linked oligosaccharides may represent an essential determinant of the structure and biological activity of zona proteins. © 1992 Wiley‐Liss, Inc.
Detection of chromosome 17‐ and X‐bearing human spermatozoa using fluorescence in situ hybridization
Authors: Han Tie Lan , Webb Graham C. , Flaherty Sean P. , Correll Anthony , Matthews Colin D. , Ford Judith H.
Published: February 2005

Fluorescence in situ hybridization (FISH) with DNA probes specific to chromosomes 17 and the X has been applied to human ejaculated sperm. After sperm nuclei were decondensed with EDTA and DTT, biotinylated alpha satellite DNA probes TR17 and TRX were separately used on preparations from thirteen healthy donors. After hybridization 96% of sperm were labelled with the TR17 probe and 48% of sperm were labelled with the TRX probe. Frequencies of 0.33% disomic 17 and 0.29% disomic X sperm were found. The frequencies of diploid sperm were assessed as 0.37% using the TR17 probe and 0.20% using the TRX probe which labelled only one half of the sperm; after correcting the result from the X‐probe to 0.40% the two frequencies are very similar. © 1992 Wiley‐Liss, Inc.
Behavior of sperm nuclei incorporated into parthenogenetic mouse eggs prior to the first cleavage division
Authors: Maleszewski Marek
Published: February 2005

When artificially activated mouse eggs are inseminated in the middle of the first cell cycle, sperm nuclei remain condensed until the first mitosis. During mitosis of the first cleavage division sperm nuclei decondense, subsequently recondense and are passively displaced to the daughter blastomeres. In the 2‐cell embryos sperm nuclei form interphase nuclei which are able to replicate DNA and to condense into discrete chromosomes during the following mitotic division. These observations suggest that the mitotic cytoplasm of 1‐cell embryos creates similar conditions for the transformation of sperm nuclei into male pronuclei as the cytoplasm of metaphase ll oocytes. © 1992 Wiley‐Liss, Inc.
Protein dynamics in sperm membranes: Implications for sperm function during gamete interaction
Authors: Wolf D. E. , McKinnon C. A. , Leyton L. , Loveland K. Lakoski , Saling P. M.
Published: February 2005

A number of mammalian sperm plasma membrane antigens have been implicated as playing a functional role in sperm‐egg interaction, by virtue of the fact that antibodies against these antigens interfere with fertilization. Two such muse sperm plasma membrane antigens are M42, a 200/220 kD glycoprotein doublet, and M5, a 150–160 kD glycoprotein. We show that both of these antigens are concentrated on the posterior region of caudal epididymal and capacitated mouse sperm heads and are relatively diffusible, as determined by fluorescence recovery after photobleaching measurements (D = 3–8 × 10–9 cm2/s with ∼ 23% diffusing). Crosslinking of these antigens with bivalent antibodies causes them to redistribute into the anterior region (acrosomal crescent) of the sperm head. In contrast, we describe a third antigen, P220, which is also localized to the posterior region of the sperm head on caudal epididymal sperm but which exhibits very little diffusion and does not redistribute upon crosslinking. Bivalent anti‐M42 blocks the ZP3‐induced acrosome reaction. We have found that monovalent Fab fragments of anti‐M42 do not block the ZP3‐induced acrosome reaction, but that inhibition is restored by addition of a second antibody which crosslinks the Fabs. Thus, crosslinking is required for both inhibition of the acrosome reaction and redistribution. This suggests that redistribution of antigen away from the posterior region of the head may be part of the mechanism of inhibition of the ZP3‐induced acrosome reaction. © 1992 Wiley‐Liss, Inc.
Genome exclusion and gametic dapi—dna content in the hybridogenetic Bacillus rossius—grandii benazzii complex (insecta phasmatodea)
Authors: Tinti Fausto , Scali Valerio
Published: February 2005

Among Sicilian stick insects, two hybridogenetic complexes have been discovered: Bacillus rossius–grandii benazzii and B. rossius–grandii grandii, which also produce androgenetic offspring. The egg maturation of the former is analyzed here through DAPI fluorom etry, which, besides the assessment of the meiotic stages, also allows their DNA measurements and the analysis of sperm‐head evolution into male pronuclei in these polyspermic eggs.

Hybridogenetic eggs undergo an extrasynthesis of chromosomes, because two groups of n autobivalents (4C each) are segregated at metaphase 1st; the two groups must correspond to the pure parental species haplosets. Then the grandii chromosomes degenerate (1st polar body), while the rossius chromosomes divide further to produce two groups of n autodiads (2C each); one of them degenerates (2nd polar body), and the other is ready to perform syngamy (female pronucleus). Meanwhile, several B. grandii sperm evolve into male pronuclei by doubling their DNA (from 1C to 2C content) and assuming an interphase nucleus appearance. If regular mixis occurs, the F1 hybrid constitution is restored but, if it fails, a fusion between two sperms may occur, originating fully paternal descendants (natural androgenesis). The genome exclusion mechanism of stick‐insect hybridogens appears to be more primitive than those observed in the already known hybridogenetic complexes of Poeciliopsis and Rana esculenta.

Unfertilized eggs of hybridogens are capable of self activation, but the cytology of the related clonally reproducing B. whitei indicates that its parthenogenetic mechanism stems from the hybridization event (hybrid theory) rather than from tychoparthenogenetic potentialities (spontaneous theory). © 1992 Wiley‐Liss, Inc.
Okadaic acid and p13suc1 modulate the reinitiation of meiosis in mouse oocytes
Authors: Gavin Anne‐Claude , Vassalli Jean‐Dominique , Cavadore Jean‐Claude , Schorderet‐Slatkine Sabine
Published: February 2005

Short‐term exposure to okadaic acid (OA), a specific inhibitor of protein phosphatases 1 and 2A, induced resumpton of meiosis, including metaphase spindle formation, in mouse oocytes treated with a phosphodiesterase inhibitor, while long incubations with OA arrested oocyte maturation at a step prior to spindle formation. To explore the basis for this difference, the overall patterns of protein synthesis and phosphorylation and the production of tissue‐type plasminogen activator (tPA), the synthesis of which is induced after germinal vesicle breakdown (GVBD), were analyzed under various OA treatments. Short‐term exposure to OA led to tPA production and did not greatly affect the maturation‐associated changes in protein phosphorylation. By contrast, a long application of OA did not result in tPA production and induced more marked changes in protein phosphorylation.

Microinjection into prophase oocytes of the the product of the fission yeast gene p13suc1, known to inhibit p34cdc2 kinase activation and/or activity, prevented meiotic reinitiation. This effect was overcome by microinjection of OA, at concentrations higher than those required for induction of maturation in the absence of p13suc1. These observations suggest that inhibition of phosphatase 1 or 2A or both triggers meiotic resumption by acting at the same site or at a site proximal to the p13suc1‐sensitive step of cdc2 kinase activation. © 1992 Wiley‐Liss, Inc.
Analysis of the DNA binding proteins interacting with specific upstream sequences of the S. purpuratus CyI actin gene
Authors: Ganster Raymond , Paul Hyacinth , Katula Karen S.
Published: February 2005

The Cyl actin gene of the sea urchin, Strongylocentrotus purpuratus, is regulated temporally and spatially within the cells of the early embryo. In an effort to understand the molecular basis for the Cyl actin pattern of expression, we have begun analyzing the protein–DNA interactions within regions previously shown to be of potential functional importance (Katula et al., 1987). Using DNase I footprinting, 10 protected regions were identified containing both conserved and apparently novel protein binding sites. Gel mobility shift competition assays confirmed the presence of multiple protein factors which specifically recognize Cyl actin upstream sequences. Determination of a relative affinity constant value (Kr) indicated that most of the protein factors preferred their respective oligonucleotide sequences vs. a synthetic competitor DNA in a range of 104. The highest affinity binding was observed for proteins binding to the oligonucleotide probe containing theoctamer element (Kr ≈︁ 106). Heterologous gel shift competition assays were carried out to investigate the interrelatedness of the protein factors. These studies, combined with other data, indicate there are both unique and redundant protein–DNA interactions in the region being examined. Possible alterations in Cyl actin DNA binding proteins were investigated during the period of Cyl transcriptional activation by gel mobility shift analysis. An increase in binding activity was observed for most of the factors, indicating that early transcriptional activity of Cyl actin may involve a general increase in the amount or activity of specific transcription factors. In addition, qualitative changes, as seen by alterations in the shift patterns, were observed for some of the oligonucleotide probes. © 1992 Wiley‐Liss, Inc.
Characterization of fibronectin as a marker for human epididymal sperm maturation
Authors: Miranda Patricia V. , Tezon Jorge G.
Published: February 2005

Fertilization involves adhesive interactions between gametes similar to those mediated by fibronectin (FN) in other cellular systems. Fibronectin has been found on the equatorial segment of ejaculated human sperm. As sperm capacity to interact with the oocyte is acquired during epididymal transit, the possible participation of FN in human sperm maturation was studied. The presence of FN in both epididymal sperm and fluid was demonstrated by the detection of a major component of 220 kD in immunoblot studies using anti‐FN antisera. The concentration of FN in soluble tissue extracts of epididymis was determined by enzyme‐linked immunosorbent assay (ELISA). A gradual increase along the length of the organ, averaging 12‐fold from proximal caput to distal corpus, was detected. Immunocytochemistry assays indicated that the number of spermatozoa with immmunoreactive FN over the equatorial segment increased from 18% in caput to 64% in distal corpus epididymis. Immunoprecipitation of medium from epididymal explants culture with anti‐FN antiserum demonstrated the de novo synthesis of FN in vitro. The greater number of FN‐positive sperm coincident with FN accumulation in distal regions of the epididymis supports the role of FN in sperm maturation. © 1992 Wiley‐Liss, Inc.
A comparison between in vitro fertilization and microinjection of immobilized spermatozoa from bulls producing spermatozoa with defects
Authors: Heuwieser W. , Yang X. , Jiang S. , Foote R. H.
Published: February 2005

The objectives of this study were to compare the fertilization rate of bovine in vitro matured oocytes by in vitro fertilization (IVF) and by microinjection of a single spermatozoon (MI) and to relate these rates with fertility reported for these bulls in artificial breeding. Bull A (Holstein) had a nonreturn rate of 75%. Semen from this bull is routinely used in our standard IVF procedure. Bull B (Ayrshire), used regularly in artificial breeding and related to bull D, had a nonreturn rate of 69.2%. Bull C (Brown Swiss), with a chromosomal translocation and trisomy, achieved a nonreturn rate of 42%. Bull D (Ayrshire) produced nonmotile spermatozoa (SPZ) and had an abnormality described as “tail stump defect.” No pregnancies sired by bull D have been reported. Oocytes were either fertilized in vitro by capacitated SPZ or by microinjection of a single immobilized SPZ into the ooplasma. SPZ were treated with 0.1 μM A23187 and used for IVF. For microinjection SPZ were cocultured for 5 h with bovine oviduct epithelial cells (BOEC) and then immobilized by freezing and thawing twice without cryoprotectant. A single batch of killed SPZ (stored at – 25°C) was used for all microinjections. All oocytes were cultured in Medium 199 for 22 h at 39°C and subsequently fixed, stained, and examined for evidence of fertilization (i.e., female and male pronucleus formation, SPZ decondensation). Fertilization rates following IVF with semen from bulls A, B, C, and D were 80%, 54%, 1%, and 2%, and following microinjection were 39%, 22%, 21%, and 34%, respectively. © 1992 Wiley‐Liss, Inc.
Embryo sex selection by a rat male‐specific antibody and the cytogenetic and developmental confirmation in cattle embryos
Authors: Utsumi Kyozo , Hayashi Mikio , Takakura Ryo , Utaka Kenji , Iritani Akira
Published: February 2005

Embryos of mouse, rabbit, goat, sheep, and cattle were separated into 2 groups on the basis of their morphology when incubated with a male‐specific antibody (qualified here as the H‐Y antibody) prepared from newborn rat testis. When morula‐stage embryos were cultured in the presence of this H‐Y antibody, the development of roughly one half of the embryos was arrested at that stage, whereas the other half continued to develop to the blastocyst stage. The developmentaly arrested group of embryos resumed their development into blastocysts when cultured in antibody‐free medium. Eighty to 90% of cattle embryos whose development was unaffected by the antibody were shown to possess a female karyotype (XX), and close to 80% of those embryos whose development was arrested possessed a male karyotype (XY). Cattle embryos whose sex had been presumptively identified by development in the presence of the H‐Y antibody were cryopreserved and transferred, and the sex of the calves was examined. The overt sex of the young born from sexed embryos was found to be the same as that determined by chromosomal analysis. © 1993 Wiley‐Liss, Inc.
Differential chromatin condensation of female and male pronuclei in mouse zygotes
Authors: Ciemerych Maria A. , Czołowska Renata
Published: February 2005

Mouse zygotes or halves of zygotes, containing either a female or a male pronucleus, were fused with ovulated metaphase II oocytes. In 59.7% of the resulting hybrid cells, the pronuclei underwent premature chromosome condensation (PCC). In some of these heterokaryons the 2 pronuclei differed in the dynamics of condensation. Detectability of differential PCC of pronuclei (dPCC) depended on the type of preparation. In hybrids with PCC, produced by fusion of intact zygotes with metaphase II oocytes and processed for whole‐mount preparations, one pronucleus was more advanced in the condensation process in 47% of cases. In air‐dried preparations dPCC was detected in as many as 94% of hybrids. Experiments with the fusion of halves of zygotes with metaphase II oocytes have shown that the differential reaction of pronuclei to condensation factor depended on their parental origin. Maternal chromatin responded faster to the condensation factor and attained more advanced stages of PCC than paternal chromatin. Different responses of the maternal and paternal pronucleus to the condensation factor suggests that the 2 pronuclei are not identical with regard to the organization of chromatin and/or the lamin composition of the nuclear envelope. © 1993 Wiley‐Liss, Inc.
Characterization of a cDNA clone coding for human testis membrane cofactor protein (MCP, CD46)
Authors: Cervoni Florence , Fenichel Patrick , Akhoundi Camelia , Hsi Bae‐Li , Rossi Bernard
Published: February 2005

Membrane cofactor protein (MCP) is a complement regulatory protein that acts as a cofactor for the cleavage of C3b and C4b by the serine protease factor I. We have previously reported the characterization of a functional MCP molecule on the acrosomal membrane. This protein migrated as a single band with a molecular weight of 40,000 Da, which is 10,000–20,000 Da smaller than the known MCP molecules, and is devoid of N‐and O‐linked sugars. We have proposed that the difference in molecular weight resulted from the lack of sugars. To investigate if this is due to the absence of glycosylation sites, we have characterized a cDNA clone from a human testis cDNA library. This cDNA corresponds to a peculiar MCP form previously described, which is characterized by the presence of the serine/threonine/proline‐rich exon C (STPC) and the cytoplasmic tail known as CYT2, and we conclude that the absence of mature oligosaccharide of the sperm MCP cannot be totally attributed to a defect of N‐ and O‐glycosylation sequences but rather reflects an alteration of the mechanisms of glycosylation in spermatozoa. The presence of functional MCP on the acrosomal membrane, as well as the other complement regulatory protein, decay‐accelerating factor, strongly suggests that these proteins may act concomitantly to protect the acrosome‐reacted spermatozoa from the attack of the complement present in the female genital tract. © 1993 Wiley‐Liss, Inc.
Cytoplasmic β‐actin promoter produces germ cell and preimplantation embryonic transgene expression
Authors: Sands Arthur T. , Hansen Thomas N. , Demayo Francesco J. , Stanley Louise A. , Xin Lei , Schwartz Robert J.
Published: February 2005

The cytoplasmic β‐actin promoter, commonly used as strong promoter in many gene regulation studies, produces a pattern of male germ cell and preimplantation, embryonic gene expression in transgenic mice. In seven of ten expressing transgenic lines, a chicken β‐actin‐lacZ fusion gene was expressed in adult testes. In addition, five of the ten lines demonstrated transgene expression in the preimplantation mouse embryo. This is the first example of transgene expression at the stages of both gamete and early embryo. Overall, the site or transgene integration appeared to influence transgene expression in adult tissues. © 1993 Wiley‐Liss, Inc.
Structural, electrical and optical properties of sol–gel derived yttrium doped ZnO films
Authors: Kaur Ravinder , Singh A. V. , Mehra R. M.
Published: February 2005

Undoped and yttrium doped zinc oxide thin films have been deposited on corning glass by dip coating technique. The effect of doping (0–4 wt%) and annealing temperature (300–500 °C) on the structural, optical and electrical properties of the produced films have been investigated. All the films show polycrystalline nature at an annealing temperature of 350 °C. The preferential c‐axis growth with lowest full width at half maximum of (002) reflection peak is seen only up to an optimum annealing temperature. A blue shift in the absorption edge is observed both, with increase in dopant concentration and annealing temperature. The electrical resistivity of the films decreases by doping with yttrium. The lowest resistivity of 3.5 × 10–2 Ω cm and an average transmittance of 86% in the visible range has been obtained in YZO films doped with 3 wt% of yttrium and annealed at 450 °C. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Exciton‐related luminescence in LuAG:Ce single crystals and single crystalline films
Authors: Zorenko Yu. , Gorbenko V. , Voloshinovskii A. , Stryganyuk G. , Mikhailin V. , Kolobanov V. , Spassky D. , Nikl M. , Blazek K.
Published: February 2005

Luminescence of the excitons and the role of anti‐site defects, as well as the peculiarities of energy transfer to the Ce3+ activator ions were investigated in Lu3Al5O12:Ce compound. The measurements of time–resolved emission spectra and decay kinetics at 9 K and 300 K under the excitation by synchrotron radiation were used. The characteristics of single crystals and single crystalline films of Lu3Al5O12:Ce were compared and differences explained in the light of substantially different concentrations of the anti‐site defects in the same material prepared by different technologies. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Angular dispersion of photons and phonons in a photonic crystal of selectively grown GaN pyramids containing an InxGa1–xN quantum well structure
Authors: Coquillat D. , Torres J. , Le Vassor d'Yerville M. , Legros R. , Lascaray J. P. , Liu C. , Watson I. M. , Martin R. W. , Chong H. M. H. , De La Rue R. M.
Published: February 2005

Angular‐dependent reflection measurements were used to map out the dispersion relations of the resonant Bloch modes, and the angular dispersion of the phonon modes, in a photonic crystal consisting of selectively grown GaN pyramids containing a single InxGa1–xN/GaN quantum well. The dispersion of the photons exhibits strong photonic crystal characteristics, while the mean indium content of the ∼2 nm thickness InxGa1–xN layer was extracted from the angular dispersion of the phonon modes. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Technical aspects of 〈$ \bf 11\bar 20 $〉 4H–SiC MOSFET processing
Authors: Blanc C. , Tournier D. , Soulière V. , Juillaguet S. , Contreras S. , Zielinski M. , Godignon P. , Monteil Y. , Camassel Jean
Published: February 2005

In order to process n‐type channel MOSFETs on 〈$ 11\bar 20 $〉‐oriented 4H–SiC wafers one has to optimise, independently, many different steps. First is the growth of the active epitaxial layer, including the effect of p‐type doping. Next is the oxidation and, finally, the n‐type implantation for source and drain formation. In this work, we investigate the growth and doping of the p‐type doped epitaxial layer on the 〈$ 11\bar 20 $〉‐oriented substrate using, both, SIMS, low temperature photoluminescence measurements and Hall effect measurement to control the final doping level. Next we investigate the change in oxidation kinetics with respect to the conventional 〈0001〉 surfaces. Finally, we evaluate the efficiency of implantation and annealing processes. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Simulation analysis of dynamical properties of Cl2 on GaAs(001)
Authors: Ozeki M. , Shimizu Y.
Published: February 2005

Dynamical behaviors of Cl2 on GaAs(001)‐(2 × 4) surface were studied by a trajectory simulation. A 612‐atom five‐layer slab of GaAs surface, with periodic boundary conditions in two dimensions, is employed in the calculation. In order to maintain the surface temperature, friction and stochastic forces are included in the simulation program. Pairwise potentials are adopted for the interaction between molecule‐surface atoms, inner atoms of molecule, and surface atoms. The simulations well describe the experimental result and provide some important insights into the energy exchange process at surface scattering, trapping/desorption process, and angle‐resolved patterns of scattered Cl2 molecule on GaAs surface. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synchronization of strongly interacting overdamped Josephson junctions
Authors: Grib Alexander , Mans Michael , Scherbel Jens , Seidel Paul
Published: February 2005

The high frequency approximation is applied for the description of phase locking in the chain of two junctions loaded by the arbitrary resonance system providing strong coupling. The derived equation of synchronization describes phase locking for junctions which McCumber parameters of an order of magnitude larger than those described in ranges of the slowly varying amplitude approximation. The developed method is applied to the chain of junctions loaded by a resonant transmission line. Obtained values of the voltage locking interval and the maximal tolerant spread of critical currents are in agreement with numerical calculations. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Practical considerations regarding the use of streptolysin-O as a permeabilising agent for cells in the investigation of exocytosis
Authors: Larbi Karen Y. , Gomperts Bastien D.
Published: February 2005

Streptolysin-O is widely used in cell biological investigations in order to make large (>12 nm) pores in the plasma membrane and so to render the cytosol directly accessible to experimental manipulation. We have compared the effect of streptolysin-O commercially formulated (Murex Diagnostics) as a diagnostic reagent in pathology with two pure reagents (a conventional purified protein, and a recombinant protein generated in E.coli) on exocytotic secretion from mast cells. For mast cells permeabilised by streptolysin obtained from the commercial source, exocytosis (of β-D-N-acetylglucosaminidase) is dependent on provision of both Ca2+ and a guanine nucleotide. In contrast, for cells permeabilised by either of the two pure proteins, a substantial extent of Ca2+-independent exocytosis can be elicited. When the Murex material is subject to dialysis or ultrafiltration, some secretion can be induced in the absence of Ca2+, indicating a modulatory function of the low mol wt additives of formulation, mainly phosphate and cysteine. However, Ca2+-independent exocytosis is still manifest when the pure proteins are reconstituted with ultrafiltrates from the Murex material. These observations indicate that reagents used to permeabilise cells should be characterised thoroughly and used with great care. Confirmation that the cytolytic activity of the Murex material derives from a cholesterol directed factor was demonstrated by inhibition of exocytosis when red blood cell derived (and hence cholesterol containing) sonicated liposomes were provided.
Phospholipase C activation in rat pituitary adenoma (GH) cells
Authors: Gordeladze Jan O. , Haugen Trine , Paulssen Eivind J. , Paulssen Ruth H.
Published: February 2005

The presence of the pertussis toxin (PTX) insensitive GTP-binding proteins (G-proteins) Gqα and/or G11α has been demonstrated in three different prolactin (PRL) and growth hormone (GH) producing pituitary adenoma cell lines. Immunoblocking of their coupling to hormone receptors indicates that Gq and/or G11 confer throliberin (TRH) responsive phospholipase C (PL-C) activity in these cells. The contention was substantiated by immunoprecipitation analyses snowing that anti Gq/11α-sera coprecipitated PL-C activity. In essence, only Gq/11 (but neither Gi2, Gi3 nor Go) seems to mediate the TRH-sensitive PL-C activity, while Go may be coupled to a basal or constitutive PL-C activity. Immunoblocking studies imply that the Bγ-complex also, to some extent, may stimulate GH3 pituitary cell line PL-C activity. Finally, the steady state levels of Gq/11α mRNA and protein were downregulated upon long term exposure of the GH3 cells to TRH (but not to vasoactive intestinal peptide = VIP).
Intrinsic fluorescence as a probe of structure-function relationships in Ca2+-transport ATPases
Authors: Ferreira Sérgio T. , Coelho-Sampaio Tatiana
Published: February 2005

Applications of intrinsic fluorescence measurements in the study of Ca2+-transport ATPases are reviewed. Since the initial reports showing that the fluorescence emission was sensitive to Ca2+ binding, a substantial amount of work has focused on the use of both steady-state and time-resolved fluorescence spectroscopy to investigate structure-function relationships in sarcoplasmic reticulum and plasma membrane Ca2+-ATPases. These studies have revealed ligand-induced conformational changes, as well as provided information on protein-protein, protein-solvent and/or protein-lipid interactions in different functional states of these proteins. The main results of these studies, as well as possible future prospects are discussed.
The genius of E. E. metchnikoff—Discoveries over the centuries
Authors: Petrov Rem V. , Ulyankina Tatyana I.
Published: February 2005

On the 15 of May we celebrated the 150th anniversary of the outstanding Russian biologist Elias E. Metchnikoff (1845–1916)—Nobel Prize winner (1908), full and honorary member of many scientific academies of the world. His main works were applied to the zoology of invertebtates, evolution, embryology, immunology, microbiology, infectious pathology, gerontology, etc. Elias Metchnikoff published essays on anthropology, theory of orthobiosis, role of social and social-hygienic factors in solving the problems of old age and life elongation. On 30 May-2 June 1995 an International Symposium dedicated to Metchnikoff's 150th anniversary was held in Moscow. This is a text of the lecture given by us at the opening ceremony.
A logical framework for evolving software systems
Authors: Alencar Paulo S. C. , de Lucena Carlos J. P.
Published: February 2005

In this paper we present a logical framework for evolving software systems in which the critical aspects of large-scale software systems maintenance are treated by an approach which considers that configuration management is essentially concerned with the management of system changes. The basis of this framework is a formal description of transitions that might be made in the soft-ware change process, the purpose of the formalism is to allow deductions to be made about the validity of such transitions. A generalised formal description of software system architectures from the viewpoint of evolving software systems is also provided in the paper. Reasoning about functional aspects of these descriptions is achieved through the interaction of a theorem prover for the proposed metalogic formalism and a theorem prover for reasoning about sequential programs. In our approach the alterations of software descriptions can be viewed as programming-in-the-large transformations which are stated by means of the descriptive/prescriptive (deontic) features of actions.
Ultrasound imaging to evaluate Creatsas vaginoplasty
Authors: Botsis D. , Deligeoroglou E. , Christopoulos P. , Aravantinos L. , Papagianni V. , Creatsas G.
Published: February 2005

Objective: To present a new imaging technique for the evaluation of the functional effectiveness of Creatsas vaginoplasty. Method: Eighteen women with Mayer–Rokitansky–Küster–Hauser syndrome underwent a transabdominal and transperineal ultrasound examination 4 weeks and 6 months after the surgical creation of a neovagina, and then yearly, with a condom filled with water as a distending and imaging medium. The functional length and width of the neovagina and its axis deviation were assessed, as well as the postoperative quality of the women's sexual life. Results: A functional vagina 10 to 12 cm in length and 4 to 5 cm in width was observed; its axis deviation, which was similar to the anatomic deviation, was easily determined; and 94.5% of the women reported a satisfactory while 5.5% reported an adequate sexual life. Conclusion: This new imaging technique is a simple and effective alternative for the evaluation of the postoperative effectiveness of colpopoiesis.
Signs of ageing, the lifespan and self-representation in European self-portraits since the 15th century
Authors: ABASTADO PHILIPPE , GUIRAMAND GILLES , BOUSQUET BERNARD
Published: February 2005

Painters' self-portraits offer the opportunity to study signs of ageing through the centuries. In this paper, we examine 687 self-portraits by 506 European painters from the 15th to the 20th century. To qualify for the analysis, painters had to be unquestionably identified, have known years of birth and death, and the self-portraits had to be dated unequivocally. ‘Age scores’ for the characteristics of the lower face were developed. Ptosis of the upper eyelid, bags under the eyes and the characteristics of beards were also recorded. Among the main findings, the painters of self-portraits that exhibited ptosis of the upper eyelid had a higher actual age than those of portraits which did not (55 versus 38 years). Similarly, those that represented bags under the eyes were older painters (47 versus 33 years). The percentages of portraits with eyelid ptosis and bags under the eyes were similar through the centuries and in three zones of Europe. The age scores of the lower half of the face were also consistent in all centuries, except at ages 40–49 years. The painters' average lifespan significantly increased during the 18th century; and within Europe a north–south lifespan gradient has been evident since the 17th century. We conclude that ageing has had similar facial manifestations over the last five centuries, except between 40 and 50 years of age.
Aggregation and Two Moral Methods
Authors: KAMM F. M.
Published: February 2005

I begin by reconsidering the arguments of John Taurek and Elizabeth Anscombe on whether the number of people we can help counts morally. I then consider arguments that numbers should count given by F. M. Kamm and Thomas Scanlon, and criticism of them by Michael Otsuka. I examine how different conceptions of the moral method known as pairwise comparison are at work in these different arguments and what the ideas of balancing and tie-breaking signify for decision-making in various types of cases. I conclude by considering how another moral method that I call virtual divisibility functions and what it helps reveal about an argument by Otsuka against those who do not think numbers count.
Was the Atlantic water temperature in the West Spitsbergen Current predictable in the 1990s?
Authors: Schlichtholz Pawel , Goszczko Ilona
Published: February 2005

A major source of heat (and salt) for the Arctic Ocean is the Atlantic Water (AW) imported from the Norwegian Sea by the West Spitsbergen Current (WSC). Analysis of temperature records from the WSC has helped to link the warming of the Arctic Ocean to changes in the North Atlantic Oscillation (NAO) index. Here we analyze, using summer hydrographic data from a meridional section at 15°E in the northern Norwegian Sea, the interannual variability in the AW hydrography and its relation to the NAO index in the 1990s. We show that while the AW temperature exhibited a tendency to lag the NAO index, the AW salinity exhibited a tendency to lead the index. A surprising conclusion is that the AW temperature in the WSC was predictable one year in advance from the AW salinity.
Dielectric method of high‐resolution gas hydrate estimation
Authors: Sun Y. F. , Goldberg D.
Published: February 2005

In‐situ dielectric properties of natural gas hydrate are measured for the first time in the Mallik 5L‐38 Well in the Mackenzie Delta, Canada. The average dielectric constant of the hydrate zones is 9, ranging from 5 to 20. The average resistivity is >5 ohm.m in the hydrate zones, ranging from 2 to 10 ohm.m at a 1.1 GHz dielectric tool frequency. The dielectric logs show similar trends with sonic and induction resistivity logs, but exhibits inherently higher vertical resolution (<5 cm). The average in‐situ hydrate saturation in the well is about 70%, ranging from 20% to 95%. The dielectric estimates are overall in agreement with induction estimates but the induction log tends to overestimate hydrate content up to 15%. Dielectric estimates could be used as a better proxy of in‐situ hydrate saturation in modeling hydrate dynamics. The fine‐scale structure in hydrate zones could help reveal hydrate formation history.
Reconciling prediction algorithms for Dst
Authors: Siscoe George , McPherron Robert L. , Liemohn Michael W. , Ridley Aaron J. , Lu Gang
Published: February 2005

The Burton et al. equation and the Ring Current Atmosphere Interaction Model (RAM) code give about equally good fits to Dst profiles of strong magnetic storms, yet they are driven by different functions of the interplanetary electric field, one rising linearly and the other eventually saturating. We show that by reformulating the Burton et al. equation such that a quadratic form of the driving term replaces the original linear form, the new prediction algorithm driven by the saturation form of the driving electric field produces about equally good fits to Dst as the original Burton et al. equation and the RAM code. The form of the quadratic driving term is constructed by specializing a general form given by dimensional analysis.
CRRES electric field power spectra and radial diffusion coefficients
Authors: Brautigam D. H. , Ginet G. P. , Albert J. M. , Wygant J. R. , Rowland D. E. , Ling A. , Bass J.
Published: February 2005

Combined Release and Radiation Effects Satellite (CRRES) Electric Field Instrument (EFI) data are used to determine the electric field power spectral density as a function of L and Kp over the frequency range 0.2 to 15.9 mHz. The power at each frequency is fit to the function P(L, Kp) = a Lb exp(cKp). Assuming a purely electrostatic field and making several other assumptions regarding the azimuthal dependence of the field fluctuations, a Kp‐dependent radial diffusion coefficient DLLE is computed from the power spectra. The model average DLLE for high activity (Kp = 6) are between 1 to 2 orders of magnitude larger than that for low activity (Kp = 1), dependent upon L and first invariant.
Middle Eocene to early Oligocene paleoceanography from Agulhas Ridge, Southern Ocean (Ocean Drilling Program Leg 177, Site 1090)
Authors: Anderson L. D. , Delaney M. L.
Published: February 2005

The Agulhas Ridge, off the tip of Africa between the Atlantic and Indian Oceans, is ideally located to capture the evolution of Paleogene‐early Neogene circulation patterns associated with global cooling. Multiproxy records of productivity (biogenic barium (Baex), opal, CaCO3 mass accumulation rates (MARs)), nutrient and organic carbon burial (reactive phosphorus (Pr) MARs), and redox state of deep waters (U enrichment) from Ocean Drilling Program (ODP) Site 1090 reflect hydrographic shifts in this region between the middle Eocene and early Oligocene (∼39–33 Ma). Several peaks in increased export productivity and burial of organic matter occurred within the late Eocene (∼36.5, ∼34, and ∼33.7 Ma), which along with surface hydrologic conditions favoring opaline organisms over calcareous organisms could have aided in the draw down of pCO2 to a threshold level that facilitated large ice sheet development on Antarctica in the earliest Oligocene. Our multiproxy approach illustrates the importance of vertical as well as spatial hydrographic reorganization in amplifying or driving climatic cooling of the middle Eocene to early Oligocene by facilitating increases in the relative or absolute burial of organic carbon.
Ground‐penetrating radar land mine imaging: Two‐dimensional seismic migration and three‐dimensional inverse scattering in layered media
Authors: Song Lin‐Ping , Liu Qing Huo
Published: February 2005

This paper presents two methods for ground‐penetrating radar (GPR) imaging of land mines: a two‐dimensional (2‐D) seismic migration method and a 3‐D nonlinear inverse scattering method. The seismic migration technique has been successfully applied to processing field data sets collected at a test site. The results show that the seismic migration technique is a useful real‐time imaging method. To image the 3‐D structure of the land mine, we have developed a full 3‐D nonlinear inverse scattering algorithm on the basis of the contrast source inversion method. To account for the ground surface and potentially other subsurface layers, the inverse scattering method uses a multilayered medium as a background. Preliminary results demonstrate that the 3‐D inverse scattering method can successfully provide high‐resolution reconstruction of high‐contrast buried objects.
Telomere shortening in leucocyte subsets of long‐term survivors of allogeneic bone marrow transplantation
Authors: Wynn R. , Thornley I. , Freedman M. , Saunders E. F.
Published: February 2005

Recent studies have demonstrated excessive telomeric shortening in peripheral blood leucocytes of bone marrow transplant (BMT) recipients. This finding has raised concerns about accelerated haemopoietic ageing that might predispose to clonal disorders and late graft failure. We studied the peripheral blood neutrophils and T cells of 14 fully engrafted long‐term survivors of BMT.

We found that in both neutrophils and T cells there was significant telomere shortening in the recipient (0.6 and 0.5 kb, respectively; P < 0.001 and < 0.04, respectively). We found no relationship between degree of shortening and the nucleated cell dose given at the time of transplant. We also demonstrated significantly longer telomeres in T cells than neutrophils from the same individual (mean 11.6 kb and 10.6 kb, respectively; P=0.0001).

We propose mechanisms to account for these observations. The replicative stress that causes this telomere shortening does not necessarily occur at the level of the most primitive haemopoietic stem cell.