bluuebunny/crossref_metadata_2025 huggingface dataset:
Shock compression of quartz in the high-pressure fluid regime
Authors: Hicks D. G. , Boehly T. R. , Celliers P. M. , Eggert J. H. , Vianello E. , Meyerhofer D. D. , Collins G. W.
Published: August 2005

The Hugoniot of quartz has been measured using laser-driven shock waves with pressures from 2 to 15 Mbars. Within this pressure range silica transforms from a liquid near melt into a dense plasma. Results are in good agreement with previous studies in part of this range performed using explosive- and nuclear-driven shocks indicating the absence of time-dependent effects for time scales between several hundred picoseconds and several hundred microseconds. These data combined with earlier data at lower pressures clearly show the increasing compressibility of silica as it transitions from solid to liquid to dense plasma regimes.
Neoclassical resonant transport of a mirror cell
Authors: Ito T. , Katanuma I.
Published: August 2005

The neoclassical resonant plateau transport in a mirror cell is studied theoretically. The analytical expression for a non-square-well magnetic field is obtained. The analytical result is applied to the GAMMA10 tandem mirror [T. Cho, M. Yoshida, J. Kohagura et al., Phys. Rev. Lett. 94, 085002–1 (2005)], which consists of several mirror cells in it, and the confinement time due to the neoclassical resonant plateau transport is determined in each mirror cell. It is found that the neoclassical resonant transport of ions trapped in the nonaxisymmetric anchor mirror cell and transition mirror cells is significantly smaller than those trapped in the central cell.
The existence of normal equilibrium in tokamaks with negative current in the column center
Authors: Pozdnyakov Yu. I.
Published: August 2005

Plasma rotation is shown to remove the impossibility of the existence of “normal” equilibrium in a tokamak with reversed current. The mathematical procedure of how to overcome the peculiarities, which appear in the equilibrium equations due to current reversal, is suggested. An example of normal tokamak equilibrium with a reversed current is constructed.
Nanosecond laser temperature-jump optical rotatory dispersion: Application to early events in protein folding/unfolding
Authors: Chen Eefei , Wen Youxian , Lewis James W. , Goldbeck Robert A. , Kliger David S. , Strauss Charlie E. M.
Published: August 2005

Nanosecond time-resolved optical rotatory dispersion (TRORD) techniques are coupled with laser temperature-jump (T-jump) triggering in an instrument that measures ultrafast protein folding-unfolding dynamics with high specificity to secondary structure. Far-ultraviolet (UV) ORD can be measured with this instrument over a wide wavelength range at times as early as 35 ns after a 3 ns laser T-jump pulse. The fundamental of a Nd:YAG laser is passed through a D2-filled Raman shifter to generate a pulse of 1.5μm infrared (IR) light that is efficiently absorbed by water. The resulting T-jump is stable for at least 1 ms before decaying back to the starting temperature with a time constant of ∼30ms. The ability to measure entire TRORD band shapes during this temporal window makes it possible to distinguish between changes in the signal due to a genuine unfolding or refolding process and changes due to artifacts. The technique, applicable to a wide variety of proteins, is demonstrated here in submillisecond unfolding studies of RNAse A and cytochrome c.
Evolution of the band-gap and band-edge energies of the lattice-matched GaInAsSb∕GaSb and GaInAsSb∕InAs alloys as a function of composition
Authors: Magri Rita , Zunger Alex , Kroemer H.
Published: August 2005

Using atomistic pseudopotential calculations we predict the evolution of the valence-band maximum energy Eυ(x,y) and conduction-band minimum energy Ec(x,y) for a compositionally graded quaternary Ga1−yInyAsxSb1−x alloy lattice matched to GaSb or InAs as a function of (x,y) or, equivalently, as a function of distance from the substrate. We find upward-concave bowing for both Ec and Eυ, in contradiction with simple interpolative models. A transition from staggered (type II) to broken-gap (type III) lineup relative to GaSb is predicted to occur at x=0.81 and y=0.92 on a GaSb substrate, and at x=0.59 and y=0.62 on an InAs substrate. In the latter case, the quaternary alloy has a minimum gap at x=0.85 and y=0.87.
Saturation mechanism of the Weibel instability in weakly magnetized plasmas
Authors: Kato Tsunehiko N.
Published: August 2005

The saturation mechanism of the Weibel instability is investigated theoretically by considering the evolution of currents in numerous cylindrical beams that are generated in the initial stage of the instability. Based on a physical model of the beams, it is shown that the magnetic field strength attains a maximum value when the currents in the beams evolve into the Alfvén current and that there exist two saturation regimes. The theoretical prediction of the magnetic field strength at saturation is in good agreement with the results of two-dimensional particle-in-cell simulations for a wide range of initial anisotropy.
Uniaxial magnetic anisotropy in cobalt films induced by oblique deposition of an ultrathin cobalt underlayer
Authors: Umlor M. T.
Published: August 2005

The in-plane magnetization of a series of 30 Å polycrystalline cobalt films on Si(111) substrates was investigated as a function of deposition angle. The films exhibited a growth-induced uniaxial magnetic anisotropy with an easy axis of magnetization that is initially perpendicular to the adatom flux direction but rotates to parallel to the deposition direction for an oblique incidence of 75°. The coercivity increased steadily for incidence angles above 30° from a value of 15 to 270 Oe at 75° depositions. A new technique to induce the uniaxial anisotropy onto a cobalt film deposited at normal incidence with the use of a cobalt underlayer deposited at oblique incidence was demonstrated. An underlayer film of 6 Å cobalt deposited at 83° induced an observed coercivity of 375 Oe in a 30 Å cobalt film.
Near-field imaging of mid-infrared surface phonon polariton propagation
Authors: Huber A. , Ocelic N. , Kazantsev D. , Hillenbrand R.
Published: August 2005

We demonstrate that mid-infrared surface phonon polariton propagation on a SiC crystal can be imaged by scattering-type near-field optical microscopy. From the infrared images, we measure the wave vector and the propagation length of locally excited surface phonon polaritons. Our method can be also applied to surface plasmon polaritons and allows to study surface polaritons in subwavelength-scale structures.
Characteristics of a sulfur-passivated InGaP∕InGaAs∕GaAs heterostructure field-effect transistor
Authors: Lai Po-Hsien , Fu Ssu-I , Tsai Yan-Ying , Yen Chih-Hung , Cheng Shiou-Ying , Liu Wen-Chau
Published: August 2005

The effect of (NH4)2Sx treatment on the device characteristics of an InGaP∕InGaAs∕GaAs heterostructure field-effect transistor are studied and demonstrated. Experimentally, it is found that the sulfur-passivated device shows significant dc characteristics including higher forward voltage, lower leakage current, lower output conductance, and higher voltage gain. The superior microwave performances with flat and wide operating region of drain saturation current are simultaneously obtained. Furthermore, the improved thermal stabilities over wide temperature range of sulfur-passivated devices are attained. Based on these advantages, the studied device with (NH4)2Sx treatment shows the promise for high-temperature and high-performance microwave applications.
Microwave-frequency loss and dispersion in ferroelectric Ba0.3Sr0.7TiO3 thin films
Authors: Booth James C. , Takeuchi Ichiro , Chang Kao-Shuo
Published: August 2005

We report on broadband microwave-frequency measurements of epitaxial ferroelectric Ba0.3Sr0.7TiO3 thin films that reveal systematic increases in the loss and dispersion as the frequency increases toward 40 GHz. Our analysis provides evidence that the origin of this increased loss and dispersion is the direct coupling of microwave energy into a broad distribution of damped soft-phonon modes. We believe that nanometer-sized polar regions in the thin films play a role in this process, resulting in lattice-dynamical loss mechanisms that extend several decades in frequency below the frequency of the soft mode in these thin-film materials.
Side-gate effects on transfer characteristics in GaN-based transversal filters
Authors: Shigekawa Naoteru , Nishimura Kazumi , Yokoyama Haruki , Hohkawa Kohji
Published: August 2005

We examine the transfer characteristics of transversal filters with side gates fabricated on unintentionally doped GaN layers grown on (0001) sapphire substrates. By positively biasing the side gates, the transfer characteristics of the filters are efficiently improved, which means that GaN-based transversal filters with side gates are potentially applicable for filtering and modulating rf signals. We further examine the capacitance in an interdigital transducer, which decreases when the side-gate bias voltage increases. This indicates that the variation in the transfer characteristics is likely to be attributable to a change in the depletion-layer thickness in the GaN layers.
Electrical characteristics of Ga2O3–TiO2 nanomixed films grown by plasma-enhanced atomic-layer deposition for gate dielectric applications
Authors: Seong Nak-Jin , Yoon Soon-Gil , Lee Won-Jae
Published: August 2005

Nanomixed Ga2O3–TiO2 films with 5 nm thickness were deposited at 200 °C on Si (001) substrates using plasma-enhanced atomic-layer deposition for gate dielectric applications. While TiO2 films deposited on Si substrates are crystallized at an annealing temperature of 500 °C, Ga2O3–TiO2 nanomixed films show an incipient crystallization at 950 °C and exhibited a good thermal stability even at about 950 °C for 1 min. The dielectric constant of TaN∕Ga2O3–TiO2∕Si capacitors is larger than that of TaN∕TiO2–Ga2O3∕Si capacitors in nanomixed films annealed at 900 °C for 1 min. The EOT of the TaN∕Ga2O3–TiO2∕Si capacitors was ∼6Å up to an annealing temperature of 700 °C but increases with increasing annealing temperature above 700 °C for 1 min. The TaN∕Ga2O3–TiO2∕Si capacitors annealed at 1000 °C exhibit a leakage current density of ∼4×10−3A∕cm2 at −1.5V and an interfacial charge density of 1.5×1011cm−2eV−1. The Ga2O3–TiO2 nanomixed films are new candidate materials for gate dielectric applications.
Aggregated diamond nanorods, the densest and least compressible form of carbon
Authors: Dubrovinskaia Natalia , Dubrovinsky Leonid , Crichton Wilson , Langenhorst Falko , Richter Asta
Published: August 2005

We report the synthesis of aggregated diamond nanorods (ADNRs) from fullerene C60 at 20(1) GPa and 2200  °C using a multianvil apparatus. Individual diamond nanoroads are of 5–20 nm in diameter and longer than 1μm. The x-ray and measured density of ADNRs is ∼0.2%–0.4% higher than that of usual diamond. The extremely high isothermal bulk modulus KT=491(3)GPa [compare to KT=442(4)GPa of diamond] was obtained by in situ x-ray diffraction study. Thus, ADNRs is the densest among all carbon materials and it has the lowest so far experimentally determined compressibility.
Process outgrowth in oligodendrocytes is mediated by CNP, a novel microtubule assembly myelin protein
Authors: Lee John , Gravel Michel , Zhang Rulin , Thibault Pierre , Braun Peter E.
Published: August 2005

Oligodendrocytes (OLs) extend arborized processes that are supported by microtubules (MTs) and microfilaments. Little is known about proteins that modulate and interact with the cytoskeleton during myelination. Several lines of evidence suggest a role for 2′,3′-cyclic nucleotide 3′-phosphodiesterase (CNP) in mediating process formation in OLs. In this study, we report that tubulin is a major CNP-interacting protein. In vitro, CNP binds preferentially to tubulin heterodimers compared with MTs and induces MT assembly by copolymerizing with tubulin. CNP overexpression induces dramatic morphology changes in both glial and nonglial cells, resulting in MT and F-actin reorganization and formation of branched processes. These morphological effects are attributed to CNP MT assembly activity; branched process formation is either substantially reduced or abolished with the expression of loss-of-function mutants. Accordingly, cultured OLs from CNP-deficient mice extend smaller outgrowths with less arborized processes. We propose that CNP is an important component of the cytoskeletal machinery that directs process outgrowth in OLs.
Intraflagellar transport (IFT) during assembly and disassembly of Chlamydomonas flagella
Authors: Dentler William
Published: August 2005

Intraflagellar transport (IFT) of particles along flagellar microtubules is required for the assembly and maintenance of eukaryotic flagella and cilia. In Chlamydomonas, anterograde and retrograde particles viewed by light microscopy average 0.12-μm and 0.06-μm diameter, respectively. Examination of IFT particle structure in growing flagella by electron microscopy revealed similar size aggregates composed of small particles linked to each other and to the membrane and microtubules. To determine the relationship between the number of particles and flagellar length, the rate and frequency of IFT particle movement was measured in nongrowing, growing, and shortening flagella. In all flagella, anterograde and retrograde IFT averaged 1.9 μm/s and 2.7 μm/s, respectively, but retrograde IFT was significantly slower in flagella shorter than 4 μm. The number of flagellar IFT particles was not fixed, but depended on flagellar length. Pauses in IFT particle entry into flagella suggest the presence of a periodic “gate” that permits up to 4 particles/s to enter a flagellum.
A glue for heterochromatin maintenance
Authors: Krouwels Ilke M. , Wiesmeijer Karien , Abraham Tsion E. , Molenaar Chris , Verwoerd Nico P. , Tanke Hans J. , Dirks Roeland W.
Published: August 2005

Trimethylation of histone H3 lysine 9 and the subsequent binding of heterochromatin protein 1 (HP1) mediate the formation and maintenance of pericentromeric heterochromatin. Trimethylation of H3K9 is governed by the histone methyltransferase SUV39H1. Recent studies of HP1 dynamics revealed that HP1 is not a stable component of heterochromatin but is highly mobile (Cheutin, T., A.J. McNairn, T. Jenuwein, D.M. Gilbert, P.B. Singh, and T. Misteli. 2003. Science. 299:721–725; Festenstein, R., S.N. Pagakis, K. Hiragami, D. Lyon, A. Verreault, B. Sekkali, and D. Kioussis. 2003. Science. 299:719–721). Because the mechanism by which SUV39H1 is recruited to and interacts with heterochromatin is unknown, we studied the dynamic properties of SUV39H1 in living cells by using fluorescence recovery after photobleaching and fluorescence resonance energy transfer. Our results show that a substantial population of SUV39H1 is immobile at pericentromeric heterochromatin, suggesting that, in addition to its catalytic activity, SUV39H1 may also play a structural role at pericentromeric regions. Analysis of SUV39H1 deletion mutants indicated that the SET domain mediates this stable binding. Furthermore, our data suggest that the recruitment of SUV39H1 to heterochromatin is at least partly independent from that of HP1 and that HP1 transiently interacts with SUV39H1 at heterochromatin.
β-Catenin controls cell sorting at the notochord–somite boundary independently of cadherin-mediated adhesion
Authors: Reintsch Wolfgang E. , Habring-Mueller Anette , Wang Renee W. , Schohl Anne , Fagotto François
Published: August 2005

In Xenopus laevis, patterning of the trunk mesoderm into the dorsal notochord and lateral somites depends on differential regulation of Wnt–β-catenin signaling. To study the cellular requirements for the physical separation of these tissues, we manipulated β-catenin activity in individual cells that were scattered within the trunk mesoderm. We found that high activity led to efficient cell sorting from the notochord to the somites, whereas reduced activity led to sorting in the opposite direction. Analysis of individual cells overexpressing β-catenin revealed that these cells were unable to establish stable contacts with notochord cells but could freely cross the boundary to integrate within the somitic tissue. Interference with cadherin-mediated adhesion disrupted tissue architecture, but it did not affect sorting and boundary formation. Based on these results, we propose that the boundary itself is the result of cell-autonomous changes in contact behavior that do not rely on differences in absolute levels of adhesion.
Rho GTPase regulation of exocytosis in yeast is independent of GTP hydrolysis and polarization of the exocyst complex
Authors: Roumanie Olivier , Wu Hao , Molk Jeffrey N. , Rossi Guendalina , Bloom Kerry , Brennwald Patrick
Published: August 2005

Rho GTPases are important regulators of polarity in eukaryotic cells. In yeast they are involved in regulating the docking and fusion of secretory vesicles with the cell surface. Our analysis of a Rho3 mutant that is unable to interact with the Exo70 subunit of the exocyst reveals a normal polarization of the exocyst complex as well as other polarity markers. We also find that there is no redundancy between the Rho3–Exo70 and Rho1–Sec3 pathways in the localization of the exocyst. This suggests that Rho3 and Cdc42 act to polarize exocytosis by activating the exocytic machinery at the membrane without the need to first recruit it to sites of polarized growth. Consistent with this model, we find that the ability of Rho3 and Cdc42 to hydrolyze GTP is not required for their role in secretion. Moreover, our analysis of the Sec3 subunit of the exocyst suggests that polarization of the exocyst may be a consequence rather than a cause of polarized exocytosis.
Sgk3 links growth factor signaling to maintenance of progenitor cells in the hair follicle
Authors: Alonso Laura , Okada Hitoshi , Pasolli Hilda Amalia , Wakeham Andrew , You-Ten Annick Itie , Mak Tak W. , Fuchs Elaine
Published: August 2005

Tyrosine kinase growth factor receptor signaling influences proliferation, survival, and apoptosis. Hair follicles undergo cycles of proliferation and apoptotic regression, offering an excellent paradigm to study how this transition is governed. Several factors are known to affect the hair cycle, but it remains a mystery whether Akt kinases that are downstream of growth factor signaling impact this equilibrium. We now show that an Akt relative, Sgk (serum and glucocorticoid responsive kinase) 3, plays a critical role in this process. Hair follicles of mice lacking Sgk3 fail to mature normally. Proliferation is reduced, apoptosis is increased, and follicles prematurely regress. Maintenance of the pool of transiently amplifying matrix cells is impaired. Intriguingly, loss of Sgk3 resembles the gain of function of epidermal growth factor signaling. Using cultured primary keratinocytes, we find that Sgk3 functions by negatively regulating phosphatidylinositol 3 kinase signaling. Our results reveal a novel and important function for Sgk3 in controlling life and death in the hair follicle.
Cyclic AMP and calcium interplay as second messengers in melatonin-dependent regulation of Plasmodium falciparum cell cycle
Authors: Beraldo Flávio H. , Almeida Fabiana M. , da Silva Aline M. , Garcia Célia R.S.
Published: August 2005

The host hormone melatonin increases cytoplasmic Ca2+ concentration and synchronizes Plasmodium cell cycle (Hotta, C.T., M.L. Gazarini, F.H. Beraldo, F.P. Varotti, C. Lopes, R.P. Markus, T. Pozzan, and C.R. Garcia. 2000. Nat. Cell Biol. 2:466–468). Here we show that in Plasmodium falciparum melatonin induces an increase in cyclic AMP (cAMP) levels and cAMP-dependent protein kinase (PKA) activity (40 and 50%, respectively).

When red blood cells infected with P. falciparum are treated with cAMP analogue adenosine 3′,5′-cyclic monophosphate N6-benzoyl/PKA activator (6-Bz-cAMP) there is an alteration of the parasite cell cycle. This effect appears to depend on activation of PKA (abolished by the PKA inhibitors adenosine 3′,5′-cyclic monophosphorothioate/8 Bromo Rp isomer, PKI [cell permeable peptide], and H89). An unexpected cross talk was found to exist between the cAMP and the Ca2+-dependent signaling pathways. The increases in cAMP by melatonin are inhibited by blocker of phospholipase C U73122, and addition of 6-Bz-cAMP increases cytosolic Ca2+ concentration, through PKA activation.

These findings suggest that in Plasmodium a highly complex interplay exists between the Ca2+ and cAMP signaling pathways, but also that the control of the parasite cell cycle by melatonin requires the activation of both second messenger controlled pathways.
Dendrite development
Authors: Ehlers Michael D.
Published: August 2005

Neurons extend elaborate dendrites studded with spines. Unexpectedly, this cellular sculpting is regulated by the origin recognition complex—the core machinery for initiating DNA replication.
11β-HSD1 inhibition ameliorates metabolic syndrome and prevents progression of atherosclerosis in mice
Authors: Hermanowski-Vosatka Anne , Balkovec James M. , Cheng Kang , Chen Howard Y. , Hernandez Melba , Koo Gloria C. , Le Grand Cheryl B. , Li Zhihua , Metzger Joseph M. , Mundt Steven S. , Noonan Heather , Nunes Christian N. , Olson Steven H. , Pikounis Bill , Ren Ning , Robertson Nancy , Schaeffer James M. , Shah Kashmira , Springer Martin S. , Strack Alison M. , Strowski Matthias , Wu Kenneth , Wu TsueiJu , Xiao Jianying , Zhang Bei B. , Wright Samuel D. , Thieringer Rolf
Published: August 2005

The enzyme 11β–hydroxysteroid dehydrogenase (HSD) type 1 converts inactive cortisone into active cortisol in cells, thereby raising the effective glucocorticoid (GC) tone above serum levels. We report that pharmacologic inhibition of 11β-HSD1 has a therapeutic effect in mouse models of metabolic syndrome. Administration of a selective, potent 11β-HSD1 inhibitor lowered body weight, insulin, fasting glucose, triglycerides, and cholesterol in diet-induced obese mice and lowered fasting glucose, insulin, glucagon, triglycerides, and free fatty acids, as well as improved glucose tolerance, in a mouse model of type 2 diabetes. Most importantly, inhibition of 11β-HSD1 slowed plaque progression in a murine model of atherosclerosis, the key clinical sequela of metabolic syndrome. Mice with a targeted deletion of apolipoprotein E exhibited 84% less accumulation of aortic total cholesterol, as well as lower serum cholesterol and triglycerides, when treated with an 11β-HSD1 inhibitor. These data provide the first evidence that pharmacologic inhibition of intracellular GC activation can effectively treat atherosclerosis, the key clinical consequence of metabolic syndrome, in addition to its salutary effect on multiple aspects of the metabolic syndrome itself.
Inducible DNA breaks in Ig S regions are dependent on AID and UNG
Authors: Schrader Carol E. , Linehan Erin K. , Mochegova Sofia N. , Woodland Robert T. , Stavnezer Janet
Published: August 2005

Class switch recombination (CSR) occurs by an intrachromosomal deletion whereby the IgM constant region gene (Cμ) is replaced by a downstream constant region gene. This unique recombination event involves formation of double-strand breaks (DSBs) in immunoglobulin switch (S) regions, and requires activation-induced cytidine deaminase (AID), which converts cytosines to uracils. Repair of the uracils is proposed to lead to DNA breaks required for recombination. Uracil DNA glycosylase (UNG) is required for most CSR activity although its role is disputed. Here we use ligation-mediated PCR to detect DSBs in S regions in splenic B cells undergoing CSR. We find that the kinetics of DSB induction corresponds with AID expression, and that DSBs are AID- and UNG-dependent and occur preferentially at G:C basepairs in WRC/GYW AID hotspots. Our results indicate that AID attacks cytosines on both DNA strands, and staggered breaks are processed to blunt DSBs at the initiating ss break sites. We propose a model to explain the types of end-processing events observed.
T cell traffic signals
Authors: Van Epps Heather L.
Published: August 2005

In 1990, Charles Mackay and colleagues combined classical physiology with modern molecular biology to provide the first concrete evidence that naive and memory T cells follow distinct migratory routes out of the bloodstream— a discovery that helped invigorate the field of lymphocyte homing.
Investigating the Putative Glycine Hinge in Shaker Potassium Channel
Authors: Ding Shinghua , Ingleby Lindsey , Ahern Christopher A. , Horn Richard
Published: August 2005

The crystal structure of an open potassium channel reveals a kink in the inner helix that lines the pore (Jiang, Y.X., A. Lee, J.Y. Chen, M. Cadene, B.T. Chait, and R. MacKinnon. 2002. Nature 417:523–526). The putative hinge point is a highly conserved glycine residue. We examined the role of the homologous residue (Gly466) in the S6 transmembrane segment of Shaker potassium channels. The nonfunctional alanine mutant G466A will assemble, albeit poorly, with wild-type (WT) subunits, suppressing functional expression. To test if this glycine residue is critical for activation gating, we did a glycine scan along the S6 segment in the background of G466A. Although all of these double mutants lack the higher-level glycosylation that is characteristic of mature Shaker channels, one (G466A/V467G) is able to generate voltage-dependent potassium current. Surface biotinylation shows that functional and nonfunctional constructs containing G466A express at comparable levels in the plasma membrane. Compared with WT channels, the shifted-glycine mutant has impairments in voltage-dependent channel opening, including a right-shifted activation curve and a decreased rate of activation. The double mutant has relatively normal open-channel properties, except for a decreased affinity for intracellular blockers, a consequence of the loss of the side chain of Val467. Control experiments with the double mutants M440A/G466A and G466A/V467A suggest that the flexibility provided by Gly466 is more important for channel function than its small size. Our results support roles for Gly466 both in biogenesis of the channel and as a hinge in activation gating.
Deregulated matriptase causes ras-independent multistage carcinogenesis and promotes ras-mediated malignant transformation
Authors: List Karin , Szabo Roman , Molinolo Alfredo , Sriuranpong Virote , Redeye Vivien , Murdock Tricia , Burke Beth , Nielsen Boye S. , Gutkind J. Silvio , Bugge Thomas H.
Published: August 2005

Overexpression of the type II transmembrane serine protease matriptase is a highly consistent feature of human epithelial tumors. Here we show that matriptase possesses a strong oncogenic potential when unopposed by its endogenous inhibitor, HAI-1. Modest orthotopic overexpression of matriptase in the skin of transgenic mice caused spontaneous squamous cell carcinoma and dramatically potentiated carcinogen-induced tumor formation. Matriptase-induced malignant conversion was preceded by progressive interfollicular hyperplasia, dysplasia, follicular transdifferentiation, fibrosis, and dermal inflammation. Furthermore, matriptase induced activation of the pro-tumorigenic PI3K–Akt signaling pathway. This activation was frequently accompanied by H-ras or K-ras mutations in carcinogen-induced tumors, whereas matriptase-induced spontaneous carcinoma formation occurred independently of ras activation. Increasing epidermal HAI-1 expression completely negated the oncogenic effects of matriptase. The data implicate dysregulated matriptase expression in malignant epithelial transformation.
The love–hate relationship between Ras and Notch
Authors: Sundaram Meera V.
Published: August 2005

The Ras and Notch signaling pathways are used over and over again during development to control many different biological processes. Frequently, these two signaling pathways intersect to influence common processes, but sometimes they cooperate and sometimes they antagonize each other. TheCaenorhabditis elegansvulva and theDrosophilaeye are two classic paradigms for understanding how Ras and Notch affect cell fates, and how the two pathways work together to control biological pattern. Recent advances in these systems reveal some of the mechanisms by which Ras and Notch can interact. Similar types of interactions in mammals may be important for determining whether and how alterations in Ras or Notch lead to cancer.
Transcription switches for protoxylem and metaxylem vessel formation
Authors: Kubo Minoru , Udagawa Makiko , Nishikubo Nobuyuki , Horiguchi Gorou , Yamaguchi Masatoshi , Ito Jun , Mimura Tetsuro , Fukuda Hiroo , Demura Taku
Published: August 2005

Land plants evolved xylem vessels to conduct water and nutrients, and to support the plant. Microarray analysis with a newly established Arabidopsis in vitro xylem vessel element formation system and promoter analysis revealed the possible involvement of some plant-specific NAC-domain transcription factors in xylem formation. VASCULAR-RELATED NAC-DOMAIN6 (VND6) and VND7 can induce transdifferentiation of various cells into metaxylem- and protoxylem-like vessel elements, respectively, in Arabidopsis and poplar. A dominant repression of VND6 and VND7 specifically inhibits metaxylem and protoxylem vessel formation in roots, respectively. These findings suggest that these genes are transcription switches for plant metaxylem and protoxylem vessel formation.
Molecular anatomy and regulation of a stable replisome at a paused eukaryotic DNA replication fork
Authors: Calzada Arturo , Hodgson Ben , Kanemaki Masato , Bueno Avelino , Labib Karim
Published: August 2005

Eukaryotic cells regulate the progression and integrity of DNA replication forks to maintain genomic stability and couple DNA synthesis to other processes. The budding yeast proteins Mrc1 and Tof1 associate with the putative MCM–Cdc45 helicase and limit progression of the replisome when nucleotides are depleted, and the checkpoint kinases Mec1 and Rad53 stabilize such stalled forks and prevent disassembly of the replisome. Forks also pause transiently during unperturbed chromosome replication, at sites where nonnucleosomal proteins bind DNA tightly. We describe a method for inducing prolonged pausing of forks at protein barriers assembled at unique sites on a yeast chromosome, allowing us to examine for the first time the effects of pausing upon replisome integrity. We show that paused forks maintain an intact replisome that contains Mrc1, Tof1, MCM–Cdc45, GINS, and DNA polymerases α and ϵ and that recruits the Rrm3 helicase. Surprisingly, pausing does not require Mrc1, although Tof1 and Csm3 are both important. In addition, the integrity of the paused forks does not require Mec1, Rad53, or recombination. We also show that paused forks at analogous barriers in the rDNA are regulated similarly. These data indicate that paused and stalled eukaryotic replisomes resemble each other but are regulated differently.
Control of liver cell fate decision by a gradient of TGFβ signaling modulated by Onecut transcription factors
Authors: Clotman Frédéric , Jacquemin Patrick , Plumb-Rudewiez Nicolas , Pierreux Christophe E. , Van der Smissen Patrick , Dietz Harry C. , Courtoy Pierre J. , Rousseau Guy G. , Lemaigre Frédéric P.
Published: August 2005

During liver development, hepatocytes and biliary cells differentiate from common progenitors called hepatoblasts. The factors that control hepatoblast fate decision are unknown. Here we report that a gradient of activin/TGFβ signaling controls hepatoblast differentiation. High activin/TGFβ signaling is required near the portal vein for differentiation of biliary cells. The Onecut transcription factors HNF-6 and OC-2 inhibit activin/TGFβ signaling in the parenchyma, and this allows normal hepatocyte differentiation. In the absence of Onecut factors, the shape of the activin/TGFβ gradient is perturbed and the hepatoblasts differentiate into hybrid cells that display characteristics of both hepatocytes and biliary cells. Thus, a gradient of activin/TGFβ signaling modulated by Onecut factors is required to segregate the hepatocytic and the biliary lineages.
Library advocacy starts at home
Authors: Borges Michael
Published: August 2005

Purpose

To give a quick and easy approach to library advocacy, with regard to the ongoing needs of keeping in touch with stakeholders due to poor or reducing government funding for public libraries, librarians are in the situation of having to advocate in new and different ways.

Design/methodology/approach

Given the state of New York and federal funding, this approach explores the best practices that anyone can apply to approach stakeholders and policy makers for more funding.

Findings

Funding for libraries in the USA is often tied to “who” the library knows and this article gives a direct “how to” approach that can be used throughout the local, state or federal lobbying process. Especially in meeting the sophisticated demands of library users, this approach ties funding to patron activities, such as reading, electronic resources and programming.

Originality/value

This snapshot on advocacy can give those in the front lines or new to the advocacy process a way to start thinking in new ways to getting an advocacy action plan in place. A web resource of state activities in the State of New York offers resources on advocacy, specifically targeted to library advocates. Other benefits include developing messages and building coalitions.
Calculation methodology for contributive managerial effect by OEE as a result of TPM activities
Authors: Kwon Ohwoon , Lee Hongchul
Published: August 2005

This paper presents a new calculating methodology for estimating the quantitative monetary managerial effects as a result of total productive maintenance (TPM) activities. The suggested methodology is to calculate the total saving monetary amount composed of contribution profit and saving costs that are obtained by improving the overall equipment efficiency (OEE) of processing type equipment. The managerial effect that is the total saved monetary effect in keeping the OEE at the 1 percent upraised condition during a given period can be calculated by the sum of additive contribution profit and saved manufacturing cost. The proposed computation methodology is demonstrated by applying to a real industrial processing type of manufacturing equipment. This newly presented model is expected to contribute to raise the maturity of TPM activities by grasping the monetary quantitative managerial effects periodically.
PCB assembly line assignment: a genetic algorithm approach
Authors: Ho W. , Ji P.
Published: August 2005

Purpose

This paper sets out to study a production‐planning problem for printed circuit board (PCB) assembly. A PCB assembly company may have a number of assembly lines for production of several product types in large volume.

Design/methodology/approach

Pure integer linear programming models are formulated for assigning the product types to assembly lines, which is the line assignment problem, with the objective of minimizing the total production cost. In this approach, unrealistic assignment, which was suffered by previous researchers, is avoided by incorporating several constraints into the model. In this paper, a genetic algorithm is developed to solve the line assignment problem.

Findings

The procedure of the genetic algorithm to the problem and a numerical example for illustrating the models are provided. It is also proved that the algorithm is effective and efficient in dealing with the problem.

Originality/value

This paper studies the line assignment problem arising in a PCB manufacturing company in which the production volume is high.
Microsatellite analysis indicates an absence of population structure among Hippoglossus hippoglossus in the north‐west Atlantic
Authors: Reid D. P. , Pongsomboon S. , Jackson T. , McGowan C. , Murphy C. , Martin‐Robichaud D. , Reith M.
Published: August 2005

To explore the population structure of Atlantic halibut Hippoglossus hippoglossus, 160 fish from four locations in the north‐west Atlantic (Bay of Fundy, Scotian Shelf, Gulf of St Lawrence and Iceland) were examined for evidence of population structure using 18 microsatellite markers. Pair‐wise FST and a model‐based cluster analysis revealed no significant differentiation between samples, although uncertainties surrounding Atlantic halibut reproductive behaviour made it difficult to ascertain that only a single breeding population had been sampled at each location
Size‐dependent microhabitat use and intraspecific competition in Cottus gobio
Authors: Davey A. J. H. , Hawkins S. J. , Turner G. F. , Doncaster C. P.
Published: August 2005

An electrofishing survey of daytime shelter microhabitat use of bullhead Cottus gobio in a southern English chalk stream revealed positive selection for moderate water velocity, vegetation cover and coarse substrata. Water depth, other forms of cover, shade and substratum embeddedness had no significant influence on the distribution of fish. Microhabitat use was size‐dependent, with patches occupied by adult fish containing coarser substrata and less blanket weed (Cladophora algae) than those occupied by smaller juvenile conspecifics. Differences in substratum use between size‐classes were less pronounced in parts of the stream shaded by the tree canopy. In laboratory tanks stocked at low fish density, both juveniles and adults favoured use of cobbles over pebbles. The response of fish to increased conspecific density was size‐dependent; juveniles reduced use of the coarse substratum whereas adults maintained their predominance in this habitat. An apparently greater shift by juveniles when in the presence of adults was significant at α = 0·10 only, as was an apparent reduction in interactions between size‐classes under low light intensity. The displacement of small juvenile fish from the preferred cobble substratum is consistent with the hypothesis that intraspecific competition contributes to the size‐related microhabitat shift observed in the field. Although there was a tendency for the strength of competition to be reduced at low light levels, the mechanism by which tree canopy cover affects microhabitat use remains uncertain.
Pantophysin (Pan I) locus divergence between inshore v. offshore and northern v. southern populations of Atlantic cod in the north‐east Atlantic
Authors: Sarvas T. H. , Fevolden S. E.
Published: August 2005

More than 6000 cod Gadus morhua, sampled in coastal and offshore waters stretching from the Barents Sea down to the North Sea, were analysed for frequencies of alleles at the scnDNA pantophysin locus (Pan I)[formerly called synaptophysin (Syp I)]. The significant allele frequency difference between the two major stocks of cod in Norway, north‐east Arctic cod (NEAC) and Norwegian coastal cod (NCC), was upheld in all years of the investigation (1993 to 2001), and applied both to larval cod and post‐juveniles of various ages. On a north‐south axis, the appearance of a latitudinal cline of post‐juvenile (≥1 year) allele frequencies was exposed. The intermediate allele frequencies in coastal areas of northern Norway, seem to a large extent to be caused by intermingling of the two stocks, although the existence of populations of coastal cod with alternative Pan I frequencies could not be ruled out. The role of selection is yet unresolved. Depth of the sampling location seemed to have an effect on the allele frequencies and their temporal stability, while there was no indication of seasonal variation in the frequencies. Breeding structure was the most likely cause for upholding the extreme divergence in Pan I frequencies between NEAC and NCC.
Opeatogenys gracilis(Pisces: Gobiesocidae): an overlooked species or another ‘Mediterranean endemism’ found in Atlantic waters?
Authors: Gonçalves E. J. , Beldade R. , Henriques M.
Published: August 2005

The occurrence of Opeatogenys gracilis outside the Mediterranean Sea is confirmed for the first time. This is probably a more common species than previously thought, but its apparent complete dependence on seagrass beds suggests the possibility of including it in the IUCN threatened species list. Some sex differences are described and a complete meristic and morphometric description of the species is presented. The occurrence of the species in the north‐east Atlantic indicates that it might be a recent dispersal from the Mediterranean Sea, or an overlooked part of the autochthonous fauna.
Branchial release of free cortisol and melatonin by rainbow trout
Authors: Ellis T. , James J. D. , Scott A. P.
Published: August 2005

Individual rainbow trout Oncorhynchus mykiss were held in a specially constructed tank that enabled water to be collected separately from the anterior and posterior ends of the fish. Measurement by radioimmunoassay showed that >95% of the cortisol and melatonin released into the water originated from the anterior end (dominated by the gills). High performance liquid chromatography confirmed the identity of both hormones.
Age and growth of Carcharhinus leucas in the northern Gulf of Mexico: incorporating variability in size at birth
Authors: Neer J. A. , Thompson B. A. , Carlson J. K.
Published: August 2005

Age and growth rates of bull shark Carcharhinus leucas[n = 255; 555–2230 mm fork length (LF)] from the northern Gulf of Mexico were estimated from ring counts on vertebral sections collected from fishery‐dependent and ‐independent surveys. Two growth models were fitted to observed data: the von Bertalanffy growth model (VBGM) with t0 as the third parameter and a modified version of the VBGM using a fixed size‐at‐birth intercept as the third parameter. To address the variability in size‐at‐birth, a Monte Carlo simulation was incorporated into the size‐at‐birth intercept. The sex‐specific growth models were not significantly different, allowing a sexes combined model to be generated. The traditional VBGM predicted a theoretical maximum size (L∞) of 3007·1 mm LF, a growth coefficient (K) of 0·042 year−1 and a theoretical age at zero length (t0) of –6·844 years. The modified VBGM with a fixed size‐at‐birth intercept of 565 mm LF predicted an L∞ of 2289·2 mm LF and a K value of 0·089 year−1. When comparing model estimates to previously published information, the traditional VBGM predicted a significantly lower theoretical maximum size and a higher growth coefficient than those produced using data collected during the 1980s. Overall, results obtained using the VBGM with a fixed size‐at‐birth produced more biologically realistic parameters than that of the VBGM with t0. The Monte‐Carlo simulation incorporating variability in size‐at‐birth produced similar results to the VBGM using a fixed size‐at‐birth. This study provides the first attempt to incorporate variability at size‐at‐birth and provide measurements of variability around the individual parameter estimates for an elasmobranch.
Sundasalanx(Sundasalangidae) is a progenetic clupeiform, not a closely‐related group of salangids (Osmeriformes): mitogenomic evidence
Authors: Ishiguro N. B. , Miya M. , Inoue J. G. , Nishida M.
Published: August 2005

Partitioned Bayesian analysis of whole mitochondrial genome sequences from 30 basal teleosts confidently placed Sundasalanx(Sundasalangidae) within the Clupeiformes, not Osmeriformes as originally thought. This study represents the first demonstration of the phylogenetic position of Sundasalanx on a phylogenetic tree.
Skin darkness is related to cortisol, but not MSH, content in post‐larval Solea senegalensis
Authors: Ruane N. M. , Makridis P. , Balm P. H. M. , Dinis M. T.
Published: August 2005

In this study it was shown that dark coloured post‐larvae of Senegalese sole Solea senegalensis, at two different ages, had elevated cortisol concentrations compared with lighter coloured individuals. As melanophore‐stimulating hormone levels were not elevated in dark coloured fish, it is possible that this hormone may not be the main melanotropic hormone involved in stress‐related skin darkening.
Seasonal foraging movements and migratory patterns of female Lamna ditropis tagged in Prince William Sound, Alaska
Authors: Hulbert L. B. , Aires‐da‐Silva A. M. , Gallucci V. F. , Rice J. S.
Published: August 2005

Conventional and electronic tags were used to investigate social segregation, distribution, movements and migrations of salmon sharks Lamna ditropis in Prince William Sound, Alaska. Sixteen salmon sharks were tagged with satellite transmitters and 246 with conventional tags following capture, and were then released in Prince William Sound during summer 1999 to 2001. Most salmon sharks sexed during the study were female (95%), suggesting a high degree of sexual segregation in the region. Salmon sharks congregated at adult Pacific salmon Oncorhynchus spp. migration routes and in bays near Pacific salmon spawning grounds in Prince William Sound during July and August. Adult Pacific salmon were the principal prey in 51 salmon shark stomachs collected during summer months in Prince William Sound, but the fish appeared to be opportunistic predators and consumed sablefish Anoplopoma fimbria, gadids, Pacific herring Clupea pallasi, rockfish Sebastes spp. and squid (Teuthoidea) even when adult Pacific salmon were locally abundant. As Pacific salmon migrations declined in late summer, the salmon sharks dispersed; some continued to forage in Prince William Sound and the Gulf of Alaska into autumn and winter months, while others rapidly moved south‐east thousands of kilometres toward the west coasts of Canada and the U.S. Three movement modes are proposed to explain the movement patterns observed in the Gulf of Alaska and eastern North Pacific Ocean: ‘focal foraging’ movements, ‘foraging dispersals’ and ‘direct migrations’. Patterns of salmon shark movement are possibly explained by spatio‐temporal changes in prey quality and density, an energetic trade‐off between prey availability and water temperature, intra‐specific competition for food and reproductive success. Transmissions from the electronic tags also provided data on depth and water temperatures experienced by the salmon sharks. The fish ranged from the surface to a depth of 668 m, encountered water temperatures from 4·0 to 16·8° C and generally spent the most time above 40 m depth and between 6 and 14° C (60 and 73%, respectively).
Pigment variability in larval Sebastes jordani off central California
Authors: Sakuma K. M. , Taylor C. A. , Watson W.
Published: August 2005

Atypical pigment was observed in pre‐flexion, flexion and post‐flexion larval Sebastes collected off central California in 1991 and 1992 that otherwise resembled Sebastes jordani. Atypical pigment occurred on the axillary region at the base of the pectoral fin (most prominent on the inner edge of the pectoral fin base adjacent to the gut), on the median and distal regions of the pectoral fin and on the median and distal regions of the pelvic fin. In addition, lower and upper jaw pigment was observed at a much smaller size in these specimens than previously described in the literature. Identifications of these atypical specimens as S. jordani were confirmed using meristic and otolith characters as well as mitochondrial DNA sequence data. The ontogenetic variability of S. jordani is described. Specimens collected north of Point Conception were more pigmented than larval S. jordani described in the literature (collected predominately south of Point Conception), suggesting geographic variation in pigment development during the larval stage.