bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrical Measurements and Optical Emission Spectroscopy of Silicon–Carbon Alloys Grown by PACVD: Correlation with Film Microstructure
Authors: Thomas L. , Tomasella E. , Badie J.M. , Berjoan R. , Ducarroir M.
Published: June 2003

Hard hydrogen‐containing silicon–carbon‐based films were grown at medium temperatures in the range 453–853 K in a plasma‐assisted (PA) CVD device using tetramethylsilane (TMS) as the precursor. TMS plasma chemistry is not clearly understood so, in order to gain a better understanding of this process, both electrical measurements, to estimate ion energy and flux, and optical emission spectroscopy (OES), to identify chemical species occurring in the gas near the film surface, have been used to establish correlations between characteristics of the discharge and the films. In this process, an increase in the energy of the ions tends to lower the silicon to carbon atomic ratio (Si/C) whatever the temperature. Since this is the opposite to what might be expected, it follows that the ion bombardment is a key factor. The Si/C variations are related to the behavior of gaseous emitting species near the plasma sheath close to an a‐SiC/H biased surface set in non‐reactive (pure argon, argon/H2), then reactive (argon/TMS) plasmas. OES reveals that only a few species (Ar, Ar+, H, and Si+) are emitting. Their corresponding lines are strongly broadened by the Doppler effect function of the applied bias voltage and plasma nature. The Si+ line exhibits two energy populations, fast and slow. The fast one is related to electron dissociative excitation processes involving ions, whereas the slow Si+ population seems to originate from neutral groups extracted from the surface or coming from complex species in the plasma gas. Up to three energy components were identified in the Hα line profile. One is typical of both the TMS dissociation and the emission of hydrogen‐containing species coming from the bombarded deposit. A comparison between the variations of relative densities of Si+ and H, and material data, indicates that the deposit can be etched or sputtered (either congruently or non‐congruently) leading, in the maximum ion energy range (120–180 eV), to a drastic modification of the film microstructure. This latter point is analyzed in connection with the coating surface hardness (17 GPa < H < 30 GPa).
A Study on the Metal Organic CVD of Pure Copper Films from Low Cost Copper(II) Dialkylamino‐2‐propoxides: Tuning the Thermal Properties of the Precursor by Small Variations of the Ligand
Authors: Becker R. , Devi A. , Weiß J. , Weckenmann U. , Winter M. , Kiener C. , Becker H.‐W. , Fischer R.A.
Published: June 2003

Pure copper metal thin films were grown on SiO2/Si(100) substrates by metal–organic (MO) CVD in a horizontal cold‐wall reactor employing the two metal–organic compounds, Cu(OCHMeCH2NR2)2, where R = Et (1) and R = Me (2) as precursors. Thermogravimetric analyses proved them to be convenient compounds for the deposition of copper without a reducing agent. Depositions were carried out at various substrate temperatures in the range 230–350 °C. X‐ray diffraction (XRD) indicated that the resulting films were highly crystalline and showed a strong (111) preferred orientation, which increased with increasing deposition temperature. Photoelectron spectroscopy (XPS) revealed that copper films deposited at 230 °C and 260 °C consisted solely of metallic copper with no detectable carbon, nitrogen, or oxygen contamination. Copper films obtained from 1 at 260 °C had a resistivity of 2.16 μΩ cm.
Rapid detection of respiring Escherichia coli O157:H7 in apple juice, milk, and ground beef by flow cytometry
Authors: Yamaguchi Nobuyasu , Sasada Makoto , Yamanaka Mio , Nasu Masao
Published: June 2003

Background

Rapid and simple methods to detect viable pathogenic microbes in foods and drinks are required. Flow cytometry was used for the rapid detection of respiring Escherichia coli O157:H7 cells in apple juice, milk, and ground beef.

Methods

CTC (5‐cyano‐2,3‐ditolyl tetrazolium chloride) was used to estimate the respiratory activity of bacteria. Fluorescein isothiocyanate (FITC)‐labeled anti‐E. coli O157:H7 direct antibody (FA) was used for the specific detection of target cells. Food samples were inoculated with starved E. coli O157:H7 and E. coli K‐12 cells, and analyzed by both fluorescent microscopy and flow cytometry after double staining with FA and CTC.

Results

Respiring E. coli O157:H7 cells in food samples showed strong fluorescence of both FA (green) and CTC (red); thus, they could be clearly and specifically distinguished from respiring E. coli K‐12 or inactive cells. A good correlation was achieved in flow cytometric analysis between the numbers of inoculated viable E. coli O157:H7 and those detected in milk and apple juice. The detection threshold for this flow cytometry for E. coli O157:H7 in milk, apple juice, and ground beef was 103 cells/ml (milk and apple juice) or 103 cells/g (ground beef) of sample when the total bacterial number in the sample was 106 cells/ml.

Conclusions

Respiring E. coli O157:H7 in food samples can be detected specifically within a few hours. Flow cytometry with FA‐CTC double staining can be used to examine food contamination with various pathogenic microbes demonstrating physiologic activity through the use of a suitable fluorescent antibody. Cytometry Part A 54A:27–35, 2003. © 2003 Wiley‐Liss, Inc.
Analysis of violet‐excited fluorochromes by flow cytometry using a violet laser diode
Authors: Telford William G. , Hawley Teresa S. , Hawley Robert G.
Published: June 2003

Background

Low power violet laser diodes (VLDs) have been evaluated as potential replacements for water‐cooled argon‐ion and krypton‐ion ultraviolet and violet lasers for DNA content analysis using the Hoechst dyes and 4,6‐diamidino‐2‐phenylindole (Shapiro HMN, Perlmutter NG: Cytometry 44:133–136, 2001). In this study, we used a VLD to excite a variety of violet‐excited fluorescent molecules important in biomedical analysis, including the fluorochromes Cascade Blue and Pacific Blue, the expressible fluorescent protein cyan fluorescent protein (CFP), and the fluorogenic alkaline phosphatase (AP) substrate 2‐(5′‐chloro‐2′‐phosphoryloxyphenyl)‐6‐chloro‐4‐(3H)‐quinazoline (ELF‐97; for endogenous AP detection and cell surface labeling with AP‐conjugated antibodies).

Methods

Comparisons were made between VLD excitation and a krypton‐ion laser emitting at 407 nm (both at higher power levels and with the beam attenuated at levels approximating the VLD) on the same FACSVantage SE stream‐in‐air flow cytometer. We evaluated a Power Technology 408‐nm VLD (30 mW) equipped with circularization optics (18 mW maximum output, set to 15 mW) and a Coherent I‐302C krypton‐ion laser emitting at power levels ranging from 15 to 75 mW.

Results

Cascade Blue, Pacific Blue, and CFP showed comparable signal‐to‐noise ratios and levels of sensitivity with VLD excitation versus the krypton‐ion laser at high and VLD‐matched power outputs. Multicolor fluorescent protein analysis with 488‐nm excitation of green fluorescent protein and DsRed and VLD excitation of CFP was therefore feasible and was demonstrated. Similar levels of excitation efficiency between krypton‐ion and VLD sources also were observed for ELF‐97 detection.

Conclusions

These evaluations confirmed that VLDs may be cost‐ and maintenance‐effective replacements for water‐cooled gas lasers for applications requiring violet excitation in addition to DNA binding dyes. Cytometry Part A 54A:48–55, 2003. Published 2003 Wiley‐Liss, Inc.
Flow cytometry as a strategy to study radiation‐induced bystander effects in co‐culture systems
Authors: Gerashchenko Bogdan I. , Howell Roger W.
Published: June 2003

Background

There is growing interest in the role of bystander effects in the biological response of mammalian cells to ionizing radiation. Qualitative and quantitative assessment of bystander effects requires quick and reliable methodologies. The present work uses a flow cytometric approach to study proliferation of bystander cells co‐cultured with irradiated cells.

Methods

Confluent monolayers of rat liver epithelial cells (WB‐F344) were irradiated with 137Cs γ‐rays at dose ranges 0.5, 1, 5, 10, and 20 Gy. Irradiated cells were mixed with unirradiated cells (i.e., bystander cells) at a ratio of 1:1 and cultured together for 24 h followed by a flow cytometry (FCM) study of their proliferation. In order to discriminate the two populations of co‐cultured cells, one of the cell populations (unirradiated cells) was stained with the lipophilic fluorescent dye DiI.

Results

Unirradiated cells, in the presence of cells irradiated at doses above 0.5 Gy, showed an enhanced cell growth by approximately 14–17%.

Conclusions

Cells irradiated with gamma rays can induce increased proliferation in neighboring unirradiated bystander cells. FCM provides an excellent basis for characterization of these and other bystander effects in co‐culture systems. Cytometry Part A 54A:1–7, 2003. © 2003 Wiley‐Liss, Inc.
Optimization of three‐ and four‐color multiparameter DNA analysis in lymphoma specimens
Authors: Plander M. , Brockhoff G. , Barlage S. , Schwarz S. , Rothe G. , Knuechel R.
Published: June 2003

Background

Simultaneous analysis of DNA and immunophenotype of lymphoma cells by flow cytometry allows the calculation of the proliferative activity and aneuploidy in even a small lymphoma population. Unfavorable DNA binding characteristics or spectral features of DNA dyes impair the accuracy of multiparameter DNA analysis and limit their clinical application. We describe here a reliable and reproducible application of both three‐ and four‐color multiparameter DNA analysis.

Methods

After immunostaining of fresh samples of peripheral blood, bone marrow and single cell suspensions of lymph nodes from healthy and lymphoma patients, a methanol fixation for TO‐PRO‐3 and DRAQ5 staining was tested.

Results

The red‐excitable TO‐PRO‐3 on a FACSCalibur is limited to two‐color antigen staining including fluorescein‐isothiocyanate and phycoerythrin‐labeled monoclonal antibodies due to its broad excitation spectrum. Although DRAQ5 is only applicable to flow cytometers equipped with a single argon laser emitting 488‐nm light, its emission spectrum can be easily separated from the FITC, PE, and PE/Texas‐Red emissions. DRAQ5 showed almost identical stoichiometric DNA binding characteristics as propidium iodide. Coefficient of variation produced by DRAQ5 staining is in the range of 3.5 and is adequate for detecting aneuploid amd near‐diploid cells.

Conclusions

These advantageous features of DRAQ5 make it a reliable candidate for multiparameter clinical studies. Cytometry Part A 54A:66–74, 2003. © 2003 Wiley‐Liss, Inc.
Developmental changes in neurite outgrowth responses of dorsal root and sympathetic ganglia to GDNF, neurturin, and artemin
Authors: Yan H. , Newgreen D.F. , Young H.M.
Published: June 2003

The ability of glial cell line–derived neurotrophic factor (GDNF), neurturin, and artemin to induce neurite outgrowth from dorsal root, superior cervical, and lumbar sympathetic ganglia from mice at a variety of development stages between embryonic day (E) 11.5 and postnatal day (P) 7 was examined by explanting ganglia onto collagen gels and growing them in the presence of agarose beads impregnated with the different GDNF family ligands. Artemin, GDNF, and neurturin were all capable of influencing neurite outgrowth from dorsal root and sympathetic ganglia, but the responses of each neuron type to the different ligands varied during development. Neurites from dorsal root ganglia responded to artemin at P0 and P7, to GDNF at E15.5 and P0, and to neurturin at E15.5, P0, and P6/7; thus, artemin, GDNF, and neurturin are all capable of influencing neurite outgrowth from dorsal root ganglion neurons. Neurites from superior cervical sympathetic ganglia responded significantly to artemin at E15.5, to GDNF at E15.5 and P0, and to neurturin at E15.5. Neurites from lumbar sympathetic ganglia responded to artemin at all stages from E11.5 to P7, to GDNF at P0 and P7 and to neurturin at E11.5 to P6/7. Combined with the data from previous studies that have examined the expression of GDNF family members, our data suggest that artemin plays a role in inducing neurite outgrowth from young sympathetic neurons in the early stages of sympathetic axon pathfinding, whereas GDNF and neurturin are likely to be important at later stages of sympathetic neuron development in inducing axons to enter particular target tissues once they are in the vicinity or to induce branching within target tissues. Superior cervical and lumbar sympathetic ganglia showed temporal differences in their responsiveness to artemin, GDNF, and neurturin, which probably partly reflects the rostrocaudal development of sympathetic ganglia and the tissues they innervate. Developmental Dynamics 227:395–401, 2003. © 2003 Wiley‐Liss, Inc.
Isolation of a novel cDNA enriched in the undifferentiated chick retina and lens
Authors: Godbout Roseline , Andison Randy , Katyal Sachin , Bisgrove Dwayne A.
Published: June 2003

By using a differential screening strategy, we have identified a previously uncharacterised gene that is preferentially expressed in chick retinal precursor cells as well as in the anterior epithelial cells of the lens at early stages of development. The EURL transcript has an open reading frame of 293 amino acids and a 3′ untranslated region of >850 nucleotides. The only recognizable feature in the EURL (early undifferentiated retina and lens) amino acid sequence is a putative coiled‐coil domain located at the C‐terminus of the protein. The human EURL orthologue maps to chromosome 21q21. Northern blot analysis, in situ hybridization of tissue sections, and whole‐mount hybridization indicate elevated levels of EURL mRNA in the embryonic dorsal retina from stage 14 (day 2) to stage 18 (day 3). At day 3.5, when >90% of the retinal cells are in the proliferative stage, EURL transcripts are found primarily in the peripheral dorsal retina, i.e., the most undifferentiated part of the dorsal retina. EURL transcripts are also detected in the lens at stage 18 and remain abundant in the proliferating epithelial cells of the lens until at least day 11. The distribution pattern of EURL in the developing retina and lens suggest a role before the events leading to cell determination and differentiation. Developmental Dynamics 227:409–415, 2003. © 2003 Wiley‐Liss, Inc.
Expression of Sox transcription factors in the developing mouse pancreas
Authors: Lioubinski Oleg , Müller Myriam , Wegner Michael , Sander Maike
Published: June 2003

Previous work has identified members of the homeodomain and basic helix‐loop‐helix families of transcription factors as critical determinants of mammalian pancreatic development. Here, we describe the identification of HMG‐box transcription factors of the Sox gene family in the mouse pancreas. We detected transcripts for Sox11, Sox4, Sox13, Sox5, Sox9, Sox8, Sox10, Sox7, Sox17, Sox18, Sox15, and Sox30 in embryonic pancreas and found Sox4, Sox9, and Sox13 in adult pancreatic islets. Expression of seven of these Sox factors was studied in more detail by in situ hybridization from the stage of early pancreatic outgrowth to birth. Expression of Sox11 was found in the mesenchyme surrounding the pancreatic buds, whereas Sox4 and Sox9 were confined to the pancreatic epithelium and later to islets. Sox13 and L‐Sox5 showed expression in most of the pancreatic epithelial cells between embryonic days 12.5 and 14.5. Sox8 and Sox10 were detected in a thin layer of cells surrounding the islets. The expression patterns of Sox genes in the embryonic pancreas suggest that they could have important and possibly redundant functions in pancreas development. Developmental Dynamics 227:402–408, 2003. © 2003 Wiley‐Liss, Inc.
AMPA‐evoked ion influx is strongest in tangential neurons of the rat neocortical intermediate zone close to the front of the migratory stream
Authors: Poluch Sylvie , Rossel Mireille , König Norbert
Published: June 2003

In addition to the classically described radially migrating neurons, embryonic cortical areas receive neurons originating from the basal ganglia. One of the migration routes is in the intermediate zone. The front of this migration moves toward the hippocampus synchronously with the edge of the dorsally extending cortical plate. We investigated whether cells close to the front have specific properties compared with those at less advanced positions. Activation of AMPA receptors in the presence of cobalt showed that a strong influx of divalent cations could be triggered in front cells by low agonist concentration, whereas the less advanced cells needed a higher concentration to incorporate detectable amounts of cobalt. As shown by in situ hybridization, this discrepancy was not due to differential expression of GluR‐2 (known to reduce permeability for divalent cations). In vivo, release of an endogenous agonist presumably affects more, or differently, the tangential cells close to the front. Developmental Dyanmics 227:416–421, 2003. © 2003 Wiley‐Liss, Inc.
Cathepsin L plays an active role in involution of the mouse mammary gland
Authors: Burke Michael A. , Hutter Dorothy , Reshamwala Rita P. , Knepper Janice E.
Published: June 2003

Involution of the mammary gland after weaning occurs in two stages. The first stage is reversible, whereas the second stage is characterized by the irreversible collapse of the alveolar structure. A differential display analysis using cDNAs from tissues obtained at various times after forced weaning of pups identified cathepsin L as up‐regulated during early involution. Levels of cathepsin L mRNA were dramatically increased within 24 hr after weaning. Cathepsin L protein detected by immunoblot was also increased during involution, reaching near maximal levels by 36 hr after weaning. In situ immunohistochemistry detected pronounced cathepsin L protein in the cytoplasm and cell periphery. Mice treated with a specific inhibitor of cathepsin L exhibited substantially reduced numbers of apoptotic cells at times up to 72 hr after weaning when compared with untreated animals. The cathepsin L inhibitor did not alter levels of cathepsin L detected in immunoblots or influence molecular weight of the cathepsin L species detected. These data suggest that cathepsin L plays a regulatory role early in the process of mammary gland involution. Developmental Dynamics 227:315–322, 2003. © 2003 Wiley‐Liss, Inc.
Expression patterns of Tgfβ1–3 associate with myocardialisation of the outflow tract and the development of the epicardium and the fibrous heart skeleton
Authors: Molin Daniël G.M. , Bartram Ulrike , Van der Heiden Kim , Van Iperen Liesbeth , Speer Christian P. , Hierck Beerend P. , Poelmann Robert E. , Gittenberger‐de‐Groot Adriana C.
Published: June 2003

Transforming growth factor‐beta (Tgfβ) is essential for normal embryogenesis. The cardiac phenotypes obtained after knockout of each of the three mammalian isoforms suggest different roles during morphogenesis. We studied cardiovascular expression of Tgfβ1–3 in parallel tissue sections of normal mouse embryos from 9.5 to 15.5 days post coitum (dpc) by using radioactive in situ hybridisation. The Tgfβ isoforms are differentially expressed in unique and in overlapping patterns during cardiovascular development. In the vessels, Tgfβ1 is found in the intima, whereas Tgfβ2 and ‐β3 are mainly present in the media and adventitia of the great arteries. Tgfβ1 is present in the endocardium at all stages examined. The Tgfβ2 signal in the endocardium of the atrioventricular canal and outflow tract (9.5 dpc) shifts during epithelial–mesenchymal transformation toward the mesenchymal cushions (10.5–11.5 dpc) after which it exhibits a marked spatiotemporal expression pattern as the cushion differentiation progresses (11.5–15.5 dpc). The myocardium underlying the endocardial cushions and the atrial muscular septum are intensely positive for Tgfβ2 at early stages (9.5–11.5 dpc) and expression decreases at 12.5 days. In contrast to earlier reports, we find marked overlap of Tgfβ2 and ‐β3 expression. Tgfβ3 expression shows a characteristic distribution in the mesenchymal cushions, suggesting a role in cushion differentiation, possibly additional to Tgfβ2. From 14.5 dpc onward, a strong Tgfβ3 signal is found in the fibrous septum primum of the atrium and in the fibrous skeleton of the heart. Special attention was paid to the proepicardial organ and its derivatives. The proepicardial organ strongly expresses Tgfβ2 as early as 9.5 days, and all isoforms are present in the epicardium from 12.5 dpc onward. The spatiotemporal cardiovascular expression of Tgfβ1–3 supports both specific and complementary functions during cardiovascular development that might explain functional redundancy between the Tgfβ‐isoforms. The information provided favors novel roles of Tgfβ1–3 in epicardial development, of Tgfβ2 in myocardialisation, and of Tgfβ3 in differentiation of the fibrous structures of the heart. Developmental Dynamics 227:431–444, 2003. © 2003 Wiley‐Liss, Inc.
Characterization of Wnt signaling components and activation of the Wnt canonical pathway in the murine retina
Authors: Liu Hong , Mohamed Othman , Dufort Daniel , Wallace Valerie A.
Published: June 2003

The neuroepithelial layer of the developing eyecup contains multipotential precursor cells that give rise to all of the neurons and the one glial cell type present in the adult retina. Patterning within the retinal neuroepithelium is regulated by cell intrinsic as well as cell extrinsic mechanisms. Although the identity of some of the signaling molecules that regulate retinal development is known, the function of many others, especially members of the Wnt family, has yet to be characterized in the context of retinal development. We undertook a comprehensive in situ hybridization analysis to examine the expression of Wnt pathway components in the developing and adult mouse neural retina. Our findings confirm and extend previous expression studies in mice and other vertebrates, as we show that Wnt‐3, ‐5a, ‐5b, and ‐7b are expressed in the neural retina and that there is a dynamic pattern of Wnt receptor (Mouse frizzled [Mfz]) and Wnt antagonist (Secreted‐frizzled‐related protein [Sfrp]) gene expression in the embryonic and perinatal neural retina. Moreover, we show that Wnt‐13 is expressed in the pigment epithelium overlying the distal part of the eyecup and the ciliary margin and that Mfz‐4, ‐6, and ‐7 are expressed in different regions within the ciliary margin. To determine where activation of canonical Wnt signaling is occurring in the retina, we examined reporter gene expression in TCF/Lef‐LacZ mice and we demonstrate that the highest levels of β‐gal activity are found in the ciliary margin, adjacent to and within the Wnt‐13 expression domain, implicating Wnt‐13 signaling in the development of the ciliary margin and its derivatives. Developmental Dynamics 227:323–334, 2003. © 2003 Wiley‐Liss, Inc.
Three‐dimensional morphology of inner ear development in Xenopus laevis
Authors: Miller Bever Michele , Jean Ying Y. , Fekete Donna M.
Published: June 2003

The three‐dimensional morphology of the membranous labyrinth of Xenopus laevis is presented from embryonic through late tadpole development (stages 28 to 52, inclusive). This was accomplished by paint‐filling the endolymphatic spaces of Xenopus ears at a series of stages, beginning with the embryonic otic vesicle and ending with the complex ear of the late tadpole. At stage 52, the inner ear has expanded approximately 23‐fold in its anterior/posterior dimension compared with stage 28 and it is a miniature of the adult form. The paint‐filling technique illustrates the dramatic changes required to convert a simple ear vesicle into the elaborate form of the adult, including semicircular canal formation and genesis of vestibular and auditory organs, and it can serve as a basis for phenotype identification in experimentally or genetically manipulated ears. Developmental Dynamics 227:422–430, 2003. © 2003 Wiley‐Liss, Inc.
Expression of MRF4 protein in adult and in regenerating muscles in Xenopus
Authors: Becker Christel , Della Gaspera Bruno , Guyot Michèle , Donsez Evelyne , Armand Anne‐Sophie , Charbonnier Frédéric , Launay Thierry , Chanoine Christophe
Published: June 2003

In Xenopus, previous studies showed that the transcripts of the myogenic regulatory factor (MRF) MRF4 accumulate during skeletal muscle differentiation, but nothing is known about the accumulation of XMRF4 protein during myogenesis. In this report, an affinity‐purified polyclonal antibody against Xenopus MRF4 was developed and used to describe the pattern of expression of this myogenic factor in the adult and in regenerating muscles. From young forming myotubes, XMRF4 protein persistently accumulated in nuclei during the regeneration process and was strongly expressed in nuclei of adult muscles. No selective accumulation of XMRF4 protein was detectable at neuromuscular junctions, but XMRF4 immunoreactivity was observed in sole plate nuclei as well as in extrasynaptic myofiber nuclei. We also report that XMRF4 protein accumulated before the establishment of neuromuscular connections, showing that innervation is not necessary for the appearance of XMRF4 protein during muscle regeneration. Developmental Dynamics 227:445–449, 2003. © 2003 Wiley‐Liss, Inc.
Erk pathway and activator protein 1 play crucial roles in FGF2‐stimulated premature cranial suture closure
Authors: Kim Hyun‐Jung , Lee Mi‐Hye , Park Hyun‐Sik , Park Mi‐Hyun , Lee Sang‐Won , Kim Shin‐Yoon , Choi Je‐Yong , Shin Hong‐In , Kim Hyun‐Jung , Ryoo Hyun‐Mo
Published: June 2003

Cranial sutures are an important growth center of the cranial bones, and the suture space must be maintained to permit the cranial adjustments needed to accommodate brain growth. Craniosynostosis, characterized by premature suture closure, mainly results from mutations that generate constitutively active fibroblast growth factor (FGF) receptors. FGF signaling, thus, is responsible for the pathogenesis of craniosynostosis. Even though FGF activates many different signaling pathways, the one involved in premature suture closure has not been defined. We observed that placing FGF2‐soaked bead on the osteogenic fronts of cultured mouse calvaria accelerates cranial suture closure and strongly induces the expression of osteopontin, an early marker of differentiated osteoblasts. FGF2 treatment also induced fos and jun mRNAs and later increased the nuclear levels of activator protein 1 (AP1). FGF2 stimulates the expression of osteopontin by inducing expression of AP1, which then binds to its response element in the osteopontin promoter. Blocking of the Erk pathway by PD98059 suppressed the AP1 and osteopontin expression stimulated by FGF2. Coincidently, blocking of the Erk pathway also significantly retarded FGF2‐accelerated cranial suture closure. Thus, the Erk pathway mediates FGF/FGF receptor–stimulated cranial suture closure, probably by stimulating synthesis of AP1 that then stimulates the differentiation of osteoblasts. Developmental Dynamics 227:335–346, 2003. © 2003 Wiley‐Liss, Inc.
Ontogenic expression of TGFβ 1, 2, and 3 and its receptors in the rat gastric mucosa
Authors: de Andrade Sá Eunice Ribeiro , Jordão Luciana Renata , Takahashi Cassia Ayumi , Alvares Eliana Parisi , Gama Patrícia
Published: June 2003

The stomach of the rat undergoes extensive changes during the formation and maturation of gastric glands. The presence of transforming growth factor beta (TGFβ) in rat milk and in the gastrointestinal tract of pups may suggest its role in this process. The current study evaluated the in vivo dynamic expression and distribution of TGFβ1, β2, β3 and their receptors TβRI and TβRII in the gastric epithelium of 20‐day fetal rats and 1‐, 14‐, 21‐, and 30‐day‐old pups. Immunohistochemistry was used to detect the proteins, and staining was classified according to intensity and cell type. The results showed that the gastric epithelium expresses TGFβ isoforms and receptors throughout development. We found that immunoreactivity paralleled the appearance of differentiated cells, such that surface mucous cells were the first to be immunostained and chief cells were the last. The intensity of reactions followed this same pattern, showing that the expression of TGFβ isoforms spread along the gland with growth. Of interest, the highest apparent activity of TGFβ was observed from 21 days onward, a period that is concomitant with weaning and maturation of most gastric cell types. In addition, surface mucous cells were strongly labeled at the basal cytoplasm at 14 days, suggesting an interaction with the connective tissue. In conclusion, the dynamic expression of TGFβ1, β2, β3, and TβRI and TβRII through stomach development suggests significant paracrine and autocrine roles for this growth factor. We propose that temporal and spatial differences may be regulated by dietary changes, which in turn control cell proliferation and differentiation in the gastric epithelium. Developmental Dynamics 227:450–457, 2003. © 2003 Wiley‐Liss, Inc.
Differential expression of tissue inhibitor of metalloproteinases type 1 (TIMP‐1) during mouse gonad development
Authors: Guyot Romain , Magre Solange , Leduque Patrick , Le Magueresse‐Battistoni Brigitte
Published: June 2003

In mammals, the gene Sry initiates signaling pathways triggering the differentiation of a testis from a sexually indifferent gonad. Assuming that these morphogenetic events may alter the proteolytic balance, the expression of matrix metalloproteinases (MMPs) and inhibitors (TIMPs) was investigated in gonads from 11.5 days postcoitum (dpc) onward, when testicular organogenesis occurs. Whereas selective MMPs and TIMPs (1–3) were detected in undifferentiated gonads (11.5 dpc) and in neonatal testes, a single TIMP (TIMP‐1) was expressed in a sexually dimorphic manner from 12.5 dpc onward (i.e., after overt male gonad differentiation), demonstrated by using a semiquantitative reverse transcriptase‐polymerase chain reaction and a Western blot analysis. To gain insight into the role of TIMP‐1, the expression of gelatinases (mRNA levels and enzyme activity) was monitored. However, no sex differences could be evidenced, indicating that TIMP‐1 was not inhibiting this class of MMPs during testis organogenesis. Apart from being an inhibitor of MMPs, TIMP‐1 is known to display growth promoting activities. Of interest, testicular TIMP‐1 (but not TIMP‐2) levels were further enhanced up to 2 weeks of age, consistent with a role in the early postnatal testicular growth. We, therefore, established an organotypic culture system in which seminiferous cords may differentiate de novo and grow, depending on culture conditions. In that system and mimicking the in vivo situation, TIMP‐1 immunolocalized strongly within the male gonadal territory and weakly in female gonads, in which no organization was evident. Experiments are now under way to determine to what extent timp‐1 is a morphogenic gene involved in seminiferous cord formation and development. Developmental Dynamics 227:357–366, 2003. © 2003 Wiley‐Liss, Inc.
Hoxb1 neural crest preferentially form glia of the PNS
Authors: Arenkiel Benjamin R. , Gaufo Gary O. , Capecchi Mario R.
Published: June 2003

The vertebrate cranial neural crest cells give rise to many complex derivatives of the head, neck, and face, including neuronal and glial cells that act in concert for proper development of the anterior–peripheral nervous system. Several genes have been implicated in the processes of neural crest specification, migration, and differentiation; among these are the hox gene clusters. To determine the fates of hox‐expressing cranial neural crest, we describe the results of a genetic lineage analysis by using the Cre/loxP system to drive the activation of different ROSA26 reporter alleles under the regulation of the hoxb1 locus. By targeting the 3′ untranslated region of the hoxb1 gene, we have preserved endogenous gene activity and have been able to accurately follow the fates of the cells derived from the hoxb1 expression domain. Emphasis was placed on identifying the cell and tissue types that arise from the rhombomere 4‐derived neural crest. Our results demonstrate that, in addition to forming much of the cartilage, bones, and muscle of the ears and neck, a significant population of rhombomere 4‐derived neural crest is fated to generate the glial component of the seventh cranial nerve. Developmental Dynamics 227:379–386, 2003. © 2003 Wiley‐Liss, Inc.
435‐bp liver regulatory sequence in the liver fatty acid binding protein (L‐FABP) gene is sufficient to modulate liver regional expression in transgenic zebrafish
Authors: Her Guor Mour , Yeh Yang‐Hui , Wu Jen‐Leih
Published: June 2003

Liver fatty acid binding protein (L‐FABP) is a small protein that is thought to play an important role in the intracellular binding and trafficking of long chain fatty acids in the liver. Expression of the gene encoding the zebrafish liver fatty acid binding protein is regulated by a 435‐bp distal region (−1944 to −1510) of the L‐FABP promoter. The 435‐bp sequence is sufficient for gene activation in the liver primordia (or bud) and continues to be active in the adult liver when positioned adjacent to the SV40 basal promoter and linked directly to green fluorescent protein. The 435‐bp sequence region has two distinct liver regulatory elements, A (−1944 to −1623) and B (−1622 to −1510), and contains multiple putative consensus binding sites. The element A sequence includes two consensus HFH and one HNF‐1α site and the element B sequence includes one consensus HNF‐3β site. Deletion of an internal 435‐bp fragment (−1944 to −1510) including the A and B elements totally ablated the liver‐specific activity of the zebrafish L‐FABP gene promoter. Deletion of either of the two elements reduces the liver activity. Mutation of the HNF‐1α site or either of the two HFH sites in the A element or the HNF‐3β site in the B element significantly altered specificity in the liver primordia of transient expression embryos. The importance of the HNF‐1α consensus binding site in the A element and the HNF‐3β consensus binding site in the B element within the 435‐bp distal region of the L‐FABP promoter region suggests that combinatorial interactions between multiple regulatory factors are responsible for the gene expression of L‐FABP in the liver. Developmental Dynamics 227:347–356, 2003. © 2003 Wiley‐Liss, Inc.
Perturbed thyroid morphology and transient hypothyroidism symptoms in Hoxa5 mutant mice
Authors: Meunier Dominique , Aubin Josée , Jeannotte Lucie
Published: June 2003

The Hox family of transcriptional regulators has been extensively studied for their role in axial and appendicular patterning. Genetic analyses have also unveiled Hox gene function in organogenesis and postnatal development. A phenotypical survey of the Hoxa5−/− mutant mice shows that the surviving mutants display symptoms of hypothyroidism, including transient growth retardation, and delayed eye opening and ear elevation. Thyroid gland morphogenesis initiates normally, but follicle formation and thyroglobulin processing are abnormal at late gestation. The expression of several molecular markers essential for thyroid gland formation and function, namely Nkx2.1, Pax8, and Titf2, is affected in the developing thyroid gland of Hoxa5−/− mutants. As a consequence, the expression of thyroid effector genes, including the thyroglobulin and thyroperoxidase genes, is perturbed. Our characterization reveals that the loss of Hoxa5 function transiently affects thyroid development in a non–cell autonomous manner. Developmental Dynamics 227:367–378, 2003. © 2003 Wiley‐Liss, Inc.
TGF‐β3–dependent SMAD2 phosphorylation and inhibition of MEE proliferation during palatal fusion
Authors: Cui Xiao‐Mei , Chai Yang , Chen Jucheng , Yamamoto Tadashi , Ito Yoshihiro , Bringas Pablo , Shuler Charles F.
Published: June 2003

Transforming growth factor (TGF) ‐β3 is known to selectively regulate the disappearance of murine medial edge epithelium (MEE) during palatal fusion. Previous studies suggested that the selective function of TGF‐β3 in MEE was conducted by TGF‐β receptors. Further studies were needed to demonstrate that the TGF‐β signaling mediators were indeed expressed and phosphorylated in the MEE cells. SMAD2 and SMAD3 were both present in the MEE, whereas SMAD2 was the only one phosphorylated during palatal fusion. SMAD2 phosphorylation was temporospatially restricted to the MEE and correlated with the disappearance of the MEE. No phosphorylated SMAD2 was found in MEE in TGF‐β3−/− mice, although nonphosphorylated SMAD2 was present. The results suggest that TGF‐β3 is required for initiating and maintaining SMAD2 phosphorylation in MEE. Phospho‐SMAD3 was not detectable in palate during normal palatal fusion. Previous results suggested TGF‐β–induced cessation of DNA synthesis in MEE cells during palatal fusion in vitro. The present results provide evidence that inhibition of MEE proliferation in vivo was controlled by endogenous TGF‐β3. The number of 5‐bromo‐2′‐deoxyuridine (BrdU) ‐labeled MEE cells was significantly reduced in TGF‐β3+/+ compared with TGF‐β3−/− mice when the MEE seam formed (t‐test, P < 0.05). This finding suggests that TGF‐β3 is required for inhibiting MEE proliferation during palatal fusion. The inhibition of MEE proliferation may be mediated by TGF‐β3–dependent phosphorylation of SMAD2. Developmental Dynamics 227:387–394, 2003. © 2003 Wiley‐Liss, Inc.
Chronological gene expression of ADAMs during testicular development: Prespermatogonia (gonocytes) express fertilin β (ADAM2)
Authors: Rosselot Carolina , Kierszenbaum Abraham L. , Rivkin Eugene , Tres Laura L.
Published: June 2003

Immediately after birth, primordial germinal cell‐derived prespermatogonia (PSG), located in the center of the testicular cords, migrate between adjacent Sertoli cells to establish contact with the cord basal lamina. PSG migration suggests continued assembly and disassembly of cell–cell contacts by a molecular mechanism that may involve integrins and their ligands, the disintegrin domain of spermatogenic cell‐specific plasma membrane proteins called ADAMs. We have analyzed the temporal gene expression of selected ADAMs in intact fetal, early postnatal, and pubertal rat testis and Sertoli–spermatogenic cell cocultures by reverse transcriptase‐polymerase chain reaction, in situ hybridization, and immunocytochemistry. We report that several ADAM transcripts are expressed in fetal, neonatal, and prepubertal testes. Cyritestin (ADAM3), ADAM5, ADAM6, and ADAM15 are expressed in day 17 fetal testes. In contrast, no expression of fertilin α (ADAM1) and fertilin β (ADAM 2) was detected in fetal testes. Fertilin β gene expression starts after postnatal day 2, subsequent to the expression of fertilin α, which occurs on postnatal day 1. After postnatal day 2, all the indicated ADAMs, including the fertilin α and fertilin β, continue to be expressed. Transcripts of spermatogenic cell‐specific fertilin α, fertilin β, ADAM3, and ADAM5 were detected during the coculture of PSG with Sertoli cells for up to 72 hr after plating. The presence of fertilin β mRNA and protein in cocultured PSG was visualized by in situ hybridization and immunocytochemistry, respectively. These observations indicate that PSG in coculture with Sertoli cells provide a suitable approach for analyzing cell–cell adhesive responses involving spermatogenic cell‐specific ADAMs. Development Dynamics 458–467, 2003. © 2003 Wiley‐Liss, Inc.
Iterative decoding of convolutional codes applied to separate coded PPM
Authors: Harada Kohsuke , Oka Ikuo , Fujiwara Chikato
Published: June 2003

Separate coding can achieve better characteristics than Reed‐Solomon code in a binary vanishing channel when combined with convolutional code. Separate coding has the advantage that decoding is easy, since partial codes are decoded independently. In past decoding methods, however, decoded information other than the partial encoder under consideration is not utilized. When separate coding is applied to a PPM channel, the output of the partial encoder in question is completely correlated with the outputs of the other encoders. Thus, it should be possible to improve the error rate of the whole system by effectively utilizing the decoded information from other decoders. The purpose of this paper is to utilize the correlation between the outputs of the partial encoder in separate coding, and to propose an iterative decoding method based on the decoded information of multiple partial encoders. The improvement in the error rate, the comparative decoding complexity, and the external information to be used in iterative decoding are investigated. Computer simulations show that characteristics close to those of maximum likelihood decoding up to approximately 0.5 dB are achieved by the proposed decoding method while limiting the increase in decoding complexity due to the increase in the number of encoders. ©2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 86(12): 78–90, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10027
Two‐dimensional resolution in the DOA finding of a single short pulse by the waveform reconstruction technique
Authors: Ishii Masanori , Iwasaki Takashi
Published: June 2003

One method of estimating the two‐dimensional direction of arrival of a single short pulse with a pulse width on the order of nanoseconds to microseconds is to compare the reconstructed waveform of the arriving wave by means of complex antenna coefficients. However, since the reconstructed wave generally depends on the plane of polarization, three dipole antennas are used for waveform reconstruction of only the vertical polarization component of the arriving wave, while the operation of the loop antenna is simulated over a wide frequency range from that for a loop antenna acting as an infinitesimal loop to a one‐wavelength resonant loop. However, the angular resolution of the direction of arrival determined by this method has not been sufficiently studied. In this paper, direction‐of‐arrival estimation from the arrival time difference among three dipole antennas, which is carried out rather easily, and waveform reconstruction comparison of the arriving wave are compared in terms of the resolution of the angle of arrival, by using a simulation based on the method of moments. The superiority of the waveform reconstruction method is verified. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 86(12): 68–77, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10096
Estimation of the optimal frame rate for video communications under bit‐rate constraints
Authors: Inazumi Yasuhiro , Yoshida Toshiyuki , Sakai Yoshinori , Yuukou Horita
Published: June 2003

The use of applications related to real‐time video communications is spreading. But it is becoming difficult to secure the bandwidth, because of the increase in the number of the users as well as the bandwidth requirements of each user. In this context, a transcoder that can recode the video data to a usable bit rate for transmission is needed. In order to maintain as high a quality of service as possible, as seen by the user, there must be a criterion for assessment of image quality, by which the amounts of video information in the space and time directions can be reduced with good balance. In the conventional transcoder, control is based mostly on the square error, but it is not always true that the square error can directly represent the video quality seen or subjectively perceived by the user (subjective assessment quality). Consequently, this paper proposes a method of estimating the frame rate (optimal frame rate) that maximizes the subjective assessment quality in the recoding of video data (original data) stored in a video server to a specified bit rate. In the proposed method, the mean opinion score (MOS) obtained by a large number of subjective assessment tests is approximated by a function containing a small number of parameters, and the parameters of the function are estimated on the basis of the features of the original image. By specifying the bit rate for the function, the optimal frame rate is determined by determining the maximum. Interval estimation of the optimal frame rate was performed by applying the proposed method to open data, and it was verified that the frame rate could be estimated with a mean error of approximately 4 frames/s. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 86(12): 54–67, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10102
Carrier pulse transmission characteristics of squared butterworth spectrums
Authors: Ishida Noriaki
Published: June 2003

In this paper, with a view to narrowing the channel spacing, a new waveform transmission system based on a rectangular spectrum is proposed. As the transmitting waveform, the k‐th power n‐stage Butterworth (BW) characteristic, which best approximates the rectangular spectrum, is used. The receiving filter is a conventional m‐stage BW type. By selecting its 3‐dB bandwidth, optimization of the received waveform is attempted. It is shown that k = 2 is the most desirable from the viewpoint of C/N and interchannel interference. With regard to this squared BW spectrum, the eye opening rate and interchannel interference are computed. It is shown that the channel spacing can be reduced to half that in the present PDC if the squared BW is used. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 86(12): 44–53, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10124
Multimode horn antenna with both high efficiency and low cross polarization
Authors: Hiroyuki Deguchi , Tsuji Mikio , Shigesawa Hiroshi
Published: June 2003

A design method for horn antennas in which high efficiency and low cross polarization can be realized at the same time is described. In the design, the excitation coefficients for the modes at the antenna aperture are derived in order to realize these characteristics. The antenna taper shape is determined by controlling multiple modes by optimization in order to obtain these coefficients on the horn aperture. The effectiveness of the design method is verified by measurements of the radiation patterns of the tested antenna in the X band and by numerical results. It is also confirmed that a high efficiency, exceeding 80%, and a low cross polarization of less than −30 dB can be obtained. It is demonstrated that a highly efficient horn antenna with a low cross polarization, not previously available, has been realized. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 86(12): 36–43, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10127
Double‐loop antennas for a circularly polarized tilted beam
Authors: Hirose Kazuhide , Okazaki Satoshi , Nakano Hisamatsu
Published: June 2003

An antenna consisting of two concentric loops is analyzed using the method of moments. The antenna radiates a circularly polarized (CP) beam tilted from the direction normal to the antenna plane (the axial direction). First, an antenna with two feeds is analyzed. The configuration parameters are optimized in such a way that the inner and outer loops radiate CP axial and conical beams, respectively. These two radiation beams are then combined to form a CP tilted beam. It is found that the tilt angle is 25°, where the axial ratio and gain are 0.6 and 10 dB, respectively. Next, the phase between the two feeds is varied. Calculations show that the beam azimuth direction varies in a range of 360°. Finally, an antenna with a single feed is analyzed. The antenna shows radiation characteristics comparable to those for the two feeds. Further calculation reveals that a VSWR of 1.0 is obtained for another single feed using electromagnetic coupling. The VSWR remains less than 2 in the frequency bandwidth (of 2.5%) for a 1‐dB gain‐drop criterion. Within this bandwidth, the axial ratio is less than 3 dB. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 86(12): 12–20, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10132