bluuebunny/crossref_metadata_2025_split huggingface dataset:
Radial migration of developing microglial cells in quail retina: A confocal microscopy study
Authors: Sánchez‐López Ana , Cuadros Miguel A. , Calvente Ruth , Tassi Mohamed , Marín‐Teva José L. , Navascués Julio 
Published: March 2004

AbstractMicroglial cells spread within the nervous system by tangential and radial migration. The cellular mechanism of tangential migration of microglia has been described in the quail retina but the mechanism of their radial migration has not been studied. In this work, we clarify some aspects of this mechanism by analyzing morphological features of microglial cells at different steps of their radial migration in the quail retina. Microglial cells migrate in the vitreal half of the retina by successive jumps from the vitreal border to progressively more scleral levels located at the vitreal border, intermediate regions, and scleral border of the inner plexiform layer (IPL). The cellular mechanism used for each jump consists of the emission of a leading thin radial process that ramifies at a more scleral level before retraction of the rear of the cell. Hence, radial migration and ramification of microglial cells are simultaneous events. Once at the scleral border of the IPL, microglial cells migrate through the inner nuclear layer to the outer plexiform layer by another mechanism: they retract cell processes, become round, and squeeze through neuronal bodies. Microglial cells use radial processes of s‐laminin‐expressing Müller cells as substratum for radial migration. Levels where microglial cells stop and ramify at each jump are always interfaces between retinal strata with strong tenascin immunostaining and strata showing weak or no tenascin immunoreactivity. When microglial cell radial migration ends, tenascin immunostaining is no longer present in the retina. These findings suggest that tenascin plays a role in the stopping and ramification of radially migrating microglial cells. © 2004 Wiley‐Liss, Inc.
Paranodal axoglial junction is required for the maintenance of the Nav1.6‐type sodium channel in the node of Ranvier in the optic nerves but not in peripheral nerve fibers in the sulfatide‐deficient mice
Authors: Suzuki Ayaka , Hoshi Tomiko , Ishibashi Tomoko , Hayashi Akiko , Yamaguchi Yoshihide , Baba Hiroko 
Published: March 2004

AbstractIn myelinated axons, voltage‐gated sodium channels specifically cluster at the nodes of Ranvier, while voltage‐gated potassium channels are located at the juxtaparanodes. These characteristic localizations are influenced by myelination. During development, Nav1.2 first appears in the predicted nodes during myelination, and Nav1.6 replaces it in the mature nodes. Such replacements may be important physiologically. We examined the influence of the paranodal junction on switching of sodium channel subunits using the sulfatide‐deficient mouse. This mutant displayed disruption of paranodal axoglial junctions and altered nodal lengths and channel distributions. The initial switching of Nav1.2 to Nav1.6 occurred in the mutant optic nerves; however, the number of Nav1.2‐positive clusters was significantly higher than in wild‐type mice. Although no signs of demyelination were observed at least up to 36 weeks of age, sodium channel clusters decreased markedly with age. Interestingly, Nav1.2 stayed in some of the nodal regions, especially where the nodal lengths were elongated, while Nav1.6 tended to remain in the normal‐length nodes. The results in the mutant optic nerves suggested that paranodal junction formation may be necessary for complete replacement of nodal Nav1.2 to Nav1.6 during development as well as maintenance of Nav1.6 clusters at the nodes. Such subtype abnormality was not observed in the sciatic nerve, where paranodal disruption was observed. Thus, the paranodal junction significantly influences the retention of Nav1.6 in the node, which is followed by disorganization of nodal structures. However, its importance may differ between the central and peripheral nervous system. © 2004 Wiley‐Liss, Inc.
Rate‐distortion optimized intra update for error resilience in MPEG‐4 video coding
Authors: Kim Woo‐Shik , Park Rae‐Hong 
Published: March 2004

AbstractMotion compensation is a powerful method to compress a video sequence. However, once an error occurs, the error propagates through the frames. Recently, the intra update method was proposed to stop the error propagation at the cost of the compression efficiency. This paper proposes an intra update method based on rate‐distortion optimization in error prone environments. The rate and the distortion are estimated using the Lagrangian optimization method to simultaneously select the coding mode and the quantization step size. The proposed method is applied to moving picture experts group (MPEG)‐4 codec, and experimental results show that it is robuster to the packet loss than the conventional ones. © 2004 Wiley Periodicals, Inc. Int J Imaging Syst Technol 13, 341–347, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.10064
Block‐based fine granularity scalable video coding with optimized rate allocation for content‐aware streaming
Authors: He Yuwen , Yang Shiqiang , Zhong Yuzhuo 
Published: March 2004

AbstractThis article proposes a novel block‐based fine granularity scalable (FGS) video coding structure with optimized rate allocation for content‐aware streaming, which is more flexible than MPEG‐4 FGS specified in the streaming profile of MPEG‐4 standard (IS‐14496). In MPEG‐4 FGS streaming, rate allocation can only be based on frame because MBs' compressed data are interlaced between bit‐planes. However in the proposed coding structure, every MB's data are independent; therefore, streaming server can allocate bits according to content's importance, and the quality of those regions of interest is enhanced selectively with more bits allocated. In this way, the streaming server can have a differentiated delivery strategy to support a personalized streaming service considering user's preference. But the uniform rate allocation of proposed block‐based FGS coding will result in a greater loss of coding efficiency than that of MPEG‐4 FGS within a quite wide bit‐rate range. An optimized and fast rate allocation method according to block's rate‐distortion is proposed to solve this critical issue. And the coding efficiency is improved successfully, which can be comparable with MPEG‐4 FGS coding and is even better up to 0.5 dB, with some sequences at medium bit‐rates. © 2004 Wiley Periodicals, Inc. Int J Imaging Syst Technol 13, 322–330, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.10066
Decompositions of complete graphs into triangles and Hamilton cycles
Authors: Bryant Darryn , Maenhaut Barbara 
Published: March 2004

AbstractFor all odd integersn ≥ 1, letGndenote the complete graph of ordern, and for all even integersn ≥ 2 letGndenote the complete graph of ordernwith the edges of a 1‐factor removed. It is shown that for all non‐negative integershandtand all positive integersn,Gncan be decomposed intohHamilton cycles andttriangles if and only ifnh + 3tis the number of edges inGn. © 2004 Wiley Periodicals, Inc.
The nucleocytoplasmic shuttling of E2F4 is involved in the regulation of human intestinal epithelial cell proliferation and differentiation
Authors: Deschênes Claude , Alvarez Laetitia , Lizotte Marie‐Ève , Vézina Anne , Rivard Nathalie 
Published: March 2004

AbstractThe specific mechanisms controlling the transition from proliferation to terminal differentiation in human intestinal epithelial cells (HIEC) remain largely undefined. Herein, we analyzed the expression and localization of Rb and E2F proteins in well‐established normal intestinal epithelial cell models which allow for the re‐enactment of the crypt‐villus axis in vitro as well as in intact epithelium and in colon cancer cells. We report that (1) expression of E2F1 is down‐regulated while E2F4 protein is sequestered in the cytoplasm during G0 arrest associated with serum deprivation, confluency, and terminal differentiation of intestinal cells; (2) concurrently, there is an accumulation of the hypophosphorylated form of the pocket proteins into the nucleus with an increased association of E2F4 with pRb and p130; (3) cells which expressed high levels of nuclear E2F4 are all positive for Ki67 staining in human fetal intestine; (4) activation of HIEC crypt cells by growth factors leads to an increase in the nuclear localization of E2F4 which may be attributable to a decrease in the serine/threonine phosphorylation of this transcription factor; (5) inhibition of p38 MAP kinase with α/β inhibitor SB203580 induces E2F4 translocation into the nucleus and its transcriptional activity. In conclusion, our data suggest a key role for E2F4 in proliferation of human intestinal crypt cells and that its cytoplasmic retention as well as its sequestration by Rb proteins may represent a critical step in initiating cell‐cycle exit. J. Cell. Physiol. 199: 262–273, 2004© 2003 Wiley‐Liss, Inc.
Ultrastructural changes in the interstitial cells of Cajal and gastric dysrhythmias in mice lacking full‐length dystrophin (mdx mice)
Authors: Vannucchi Maria‐Giuliana , Zizzo Maria‐Grazia , Zardo Claudio , Pieri Laura , Serio Rosa , Mulè Flavia , Faussone‐Pellegrini Maria‐Simonetta 
Published: March 2004

AbstractAt least two populations of c‐kit positive interstitial cells of Cajal (ICC) lie in the gastric wall, one located at the myenteric plexus level has a pace‐making function and the other located intramuscularly is intermediary in the neurotransmission and regenerates the slow waves. Both of these ICC sub‐types express full‐length dystrophin. Mdx mice, an animal model lacking in full‐length dystrophin and used to study Duchenne muscular dystrophy (DMD), show gastric dismotilities. The aim of the present study was to verify in mdx mice whether: (i) gastric ICC undergo morphological changes, through immunohistochemical and ultrastructural analyses; and (ii) there are alterations in the electrical activity, using intracellular recording technique. In control mice, ICC sub‐types showed heterogeneous ultrastructural features, either intramuscularly or at the myenteric plexus level. In mdx mice, all of the ICC sub‐types underwent important changes: coated vesicles were significantly more numerous and caveolae significantly fewer than in control; moreover, cytoskeleton and smooth endoplasmic reticulum were reduced and mitochondria enlarged. c‐Kit‐positivity and integrity of the ICC networks were maintained. In the circular muscle of normal mice slow waves, which consisted of initial and secondary components, occurred with a regular frequency. In mdx mice, slow waves occurred in a highly dysrhythmic fashion and they lacked a secondary component. We conclude that the lack of the full‐length dystrophin is associated with ultrastructural modifications of gastric ICC, most of which can be interpreted as signs of new membrane formation and altered Ca2+ handling, and with defective generation and regeneration of slow wave activity. J. Cell. Physiol. 199: 293–309, 2004© 2003 Wiley‐Liss, Inc.
Recovery of cadmium from a zinc hydrometallurgical leachate using reactive emulsion liquid membrane technology
Authors: Fang Jianzhang , Tang Bin , Li Minyu , Xu Zhenghe 
Published: March 2004

AbstractA new emulsion liquid membrane process using 3,5‐diisopropylsalicylic acid (DIPSA) and triisobutylphosphine sulfide (TIBPS) as carriers, and ammonium sulfide (NH4)2S as precipitant is described. The reactive nature of sulfide ions with extracted cadmium ions in the internal aqueous phase significantly increases cadmium recovery and minimizes zinc impurities. The new process is applied to the enrichment of a low concentration of cadmium ions from a solution containing a high concentration of zinc ions. Under optimum operating conditions, a single stage process produced a cadmium recovery of 98% at a cadmium sulfide content of 99.6%. The results are encouraging for potential applications in zinc hydrometallurgy for recovery of cadmium from sulfuric acid leaching solution of zinc ores. Copyright © 2004 Society of Chemical Industry
Thermal deactivation and inhibition of D‐Amino acid oxidase in permeabilized cells of the yeast Trigonopsis variabilis
Authors: Moreno José A , Ruiz César A , Catalán Jacinto , Galán Miguel A 
Published: March 2004

AbstractThe inhibition of D‐amino acid oxidase contained in permeabilized cells of the yeast Trigonopsis variabilis by α‐keto acids (pyruvic acid, phenylpyruvic acid and 4‐methylthio‐2‐oxobutanoic acid), products of the transformation of the corresponding D‐amino acids, was studied. In all cases, inhibition was of the mixed type and significant differences with respect to the inhibition shown by the enzyme from other sources such as pig kidney or the yeast Rhodotorula gracilis were observed. A study was also made of the thermal deactivation of the enzyme contained in permeabilized cells of T variabilis in the temperature range 30–50 °C in sodium phosphate and Tris hydroxylmethyl aminomethane + CaCl2 buffers. A deactivation mechanism with two steps in series is proposed to account for the variation in activity with time. The results suggest that the enzyme shows greater stability in phosphate buffer, with half‐lives between 7.6 days at 30 °C and 8.6 h at 50 °C. Copyright © 2004 Society of Chemical Industry
Recovery of 2,4‐dichlorophenol from acidic aqueous streams by Membrane Aromatic Recovery System (MARS)
Authors: Dastgir Muhammad G , Ferreira Frederico C , Peeva Ludmila G , Livingston Andrew G 
Published: March 2004

AbstractThis study describes the successful recovery of 2,4‐dichlorophenol (DCP) from wastewater using the Membrane Aromatic Recovery System (MARS). In the MARS process a non‐porous membrane separates a wastewater stream and a stripping solution. DCP is extracted from the wastewater and concentrated in its ionic form in the stripping solution, with pH ≫ pKa DCP. The MARS extraction stage was operated in batch mode with the stripping solution placed inside, and the wastewater stream outside, the membrane tubes. Advantages of this configuration are avoidance of membrane blockage, reduction of stripping solution volume and operational flexibility. The stability and mass‐transfer characteristics of two different membrane materials, poly(dimethylsiloxane) (PDMS) and ethylene–propylene diene terpolymer (EPDM), were tested in DCP solutions with different acidities in order to simulate real industrial waste streams. EPDM exhibits one order of magnitude lower mass‐transfer rates than PDMS (1.4 × 10−7 m s−1 vs 20 × 10−7 m s−1 at 30 °C and 2.4 × 10−7 m s−1 vs 39 × 10−7 m s−1 at 60 °C), however its higher resistance to acid attack provides higher membrane lifetimes. This can be crucial for MARS processes treating real acidic industrial wastewater. A 97% recovery of DCP with a water content of 15 wt% was obtained upon neutralisation of the stripping solution. Copyright © 2004 Society of Chemical Industry
Use of the wings in manipulative and suspensory behaviors during feeding by frugivorous bats
Authors: Vandoros Jason Demetri , Dumont Elizabeth Rachel 
Published: March 2004

AbstractFrugivory evolved independently in Old and New World fruit bats (Families Pteropodidae and Phyllostomidae, respectively) and anecdotal reports state that these bats use their wings in different ways for manipulating food items and postural support during feeding. However, these often‐cited behavioral differences have not been documented systematically. Here we report observations of manipulative and suspensory behavior collected from 41 individuals representing five phyllostomid and six pteropodid species. During feeding, phyllostomids used both feet to suspend themselves and invariably manipulated food with the wrists and thumbs of both wings. Most pteropodids in our sample used their thumbs for suspension during feeding and none manipulated fruit with their wings. The suspensory and feeding behaviors of pteropodids varied widely and there were significant differences between species. Discrepancies between phyllostomids and pteropodids in the use of the wings during feeding are associated with previously reported differences in wrist morphology. Based on examination of manipulative and suspensory behaviors in a phylogenetic context, we suggest that differences between pteropodids and phyllostomids reflect the distinct ancestral conditions from which these bats evolved. J. Exp. Zool. 301A:361–366, 2004. © 2004 Wiley‐Liss, Inc.
Histology and ultrastructure of male mullerian gland of Uraeotyphlus narayani (Amphibia: Gymnophiona)
Authors: George Jancy M. , Smita Mathew , Oommen Oommen V. , Akbarsha M.A. 
Published: March 2004

AbstractThis study reports the anatomy, histology, and ultrastructure of the male Mullerian gland of the caecilian Uraeotyphlus narayani, based on dissections, light microscopic histological and histochemical preparations, and transmission electron microscopic observations. The posterior end of the Mullerian duct and the urinogenital duct of this caecilian join to form a common duct before opening into the cloaca. The boundary of the entire gland has a pleuroperitoneum, followed by smooth muscle fibers and connective tissue. The Mullerian gland is composed of numerous individual tubular glands separated from each other by connective tissue. Each gland has a duct, which joins the central Mullerian duct. The ducts of the tubular glands are also surrounded by abundant connective tissue. The tubular glands differ between the column and the base in regard to the outer boundary and the epithelial organization. The basement membrane of the column is so thick that amoeboid cells may not penetrate it, whereas that around the base of the gland is thin and appears to allow migration of amoeboid cells into and out of the basal aspect of the gland. The epithelium of the column has nonciliated secretory cells with basal nuclei and ciliated nonsecretory cells with apical nuclei. In the epithelium of the base there are secretory cells, ciliated cells, and amoeboid cells. The epithelium of ducts of the tubular glands is formed of ciliated dark cells and microvillated light cells. The epithelium of the central duct is formed of ciliated dark cells also possessing microvilli, ciliated light cells also possessing microvilli, and microvillated light cells that lack cilia. It is regressed during March to June when the testis lobes are in a state of quiescence. The Mullerian gland is active in secretion during July to February when the testis is active in spermatogenesis. J. Morphol. 260:33–56, 2004. © 2004 Wiley‐Liss, Inc.
Morphology and function of male genitalia (spermatophores) in Euscorpius italicus (Euscorpiidae, Scorpiones): Complex spermatophore structures enable safe sperm transfer
Authors: Jacob Alain , Gantenbein Iris , Braunwalder Matt E. , Nentwig Wolfgang , Kropf Christian 
Published: March 2004

AbstractThe structure and function of the spermatophore of Euscorpius italicus are analyzed. We show how the spermatophore gets shaped from two hemispermatophores and for the first time the sperm transfer mechanism is shown in detail, illustrating function and importance of all complex lobe structures of an euscorpiid spermatophore. A detailed description of the interaction of spermatophore and female genitalia is given. The capsular region of the spermatophore bears different lobes: The distal and basal lobes hook into two cavities on the inner side of the female's genital operculum. A so‐called “crown‐like structure” hooks into a membranous area in the genital atrium. During sperm transfer, these crown‐like structures move backwards, in this way widening the female's genital opening. The sperm duct of the spermatophore is coated with numerous spicules on its outer side, which could serve as a sealing mechanism and/or may stimulate the female. Furthermore, we conclude that “safeguarding of sperm transfer” is one driving force for evolution of male genital complexity in scorpions, but also sexual selection by cryptic female choice could partly play a role. J. Morphol. 260:72–84, 2004. © 2004 Wiley‐Liss, Inc.
Distribution of serotonin in the central nervous system of the blood‐feeding heteropteran, Triatoma infestans (Heteroptera: Reduviidae)
Authors: Settembrini Beatriz P. , Villar Marcelo J. 
Published: March 2004

AbstractThe distribution of serotonin was studied in the Triatoma infestans central nervous system by using immunocytochemistry. Serotonin immunoreactive cell bodies and fibers were observed in the brain, subesophageal ganglion, and thoracic ganglia. In the brain, serotonin‐like immunoreactivity was detected in a limited number of somata, which gave rise to an extensive network of labeled neurites in patterned as well as in nonglomerular neuropils. Immunolabeled perikarya were observed in the optic lobe and in the anteromedial and caudolateral soma rinds of the protocerebrum. Deutocerebral immunoreactive somata were mainly found in the medial layer surrounding the antennal lobe glomeruli, as well as in relationship to the antennal mechanosensory and motor center. The subesophageal ganglion contained serotonin immunoreactive perikarya of variable sizes and moderate to low density of positive fibers. In the prothoracic ganglion, immunoreactive somata were detected near the cephalic connectives as well as in its caudal end. Serotonin immunoreactive somata and fibers were observed in the posterior ganglion of the thorax, with the abdominal neuromeres harboring the highest number of immunolabeled perikarya. These results show that there is a widespread unique serotonergic system in the CNS of Triatoma infestans and suggest that the indolamine could act as a neuromodulator or as a neurohormone. J. Morphol. 260:21–32, 2004. © 2004 Wiley‐Liss, Inc.
Modifications of the falciform process in the eye of beloniformes (Teleostei: Atherinomorpha): Evolution of a curtain‐like septum in the eye
Authors: Reckel Frank , Melzer Roland R. 
Published: March 2004

AbstractIn order to comparatively analyze curtain‐like septa in the eyes of visually orientated “close‐to‐surface‐predators” among atherinomorph teleosts, we examined the eyes of 24 atherinomorph species under a binocular microscope with regard to the falciform process and related structures in the vitreous cavity. Additionally, falciform process samples were analyzed by transmission electron microscopy. All the studied representatives of the Cyprinodontiformes and Atheriniformes, and of one of the beloniform suborder, Adrianichthyioidei, possess a “typical” processus falciformis. In the eyes of the representatives of the other beloniform suborder, Belonoidei, however, pigmented structures that originate in the region of the optic disc and protrude into the vitreous cavity were noted. In the Hemiramphidae (halfbeaks) and Exocoetidae (flying fishes) these pigmented structures have a more cone‐like shape, whereas in the Belonidae (needlefishes) and Scomberesocidae (sauries) horizontally oriented heavily pigmented curtain‐like septa occur that divide the vitreous cavity dorsoventrally. It is suggested that the “typical” processus falciformis represents a plesiomorphic feature within the Atherinomorpha, whereas the pigmented modifications of the falciform process must be seen as a synapomorphic character state of the Belonoidei. The curtain‐like septum of the Belonidae and Scomberesocidae might have evolved from the cone‐like structures that are found in the Exocoetoidea. The functional significance of the pigmented structures in the eye is as yet not clear, except for the curtain‐like septum found in Belonidae. It might play a role in visual orientation near the water surface at Snell's window. J. Morphol. 260:13–20, 2004. © 2004 Wiley‐Liss, Inc.