bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrospinning highly aligned long polymer nanofibers on large scale by using a tip collector
Authors: Rafique Javed , Yu Jie , Yu Jiliang , Fang Gang , Wong K. W. , Zheng Z. , Ong H. C. , Lau W. M.
Published: August 2007

The authors developed a very simple alignment technique by which highly aligned polymer nanofibers of length >25cm were electrospun over a lateral range as large as 63cm. This technique is based on a modified configuration, application of a tip collector, and sideward ejection. The salient feature of the electrospinning process is the production of single nanofibers one by one, which was clearly confirmed by real-time images taken by a high-speed camera. Aligned polycaprolactone, polyacrylonitrile, and carbon nanofibers were prepared by this method.
Acousto-optical multiple interference switches
Authors: Beck M. , de Lima M. M. , Wiebicke E. , Seidel W. , Hey R. , Santos P. V.
Published: August 2007

The authors introduce an alternative approach for acousto-optical light control based on the interference of light propagating through several waveguides, each subjected to a periodic refractive index modulation induced by a surface acoustic wave. The feasibility of the concept is demonstrated by the realization of an optical switch for arbitrary time intervals with an on/off contrast ratio of 20.
Correlation between the lattice parameter and the dielectric tunability in nonepitaxial Ba0.5Sr0.5TiO3 thin films
Authors: Delprat Sébastien Luc , Durand Christophe , Oh JaeHo , Chaker Mohamed , Wu Ke
Published: August 2007

Nonepitaxial Ba0.5Sr0.5TiO3 (BST) films intended for tunable-microwave applications are deposited on alumina substrate by reactive pulsed laser deposition. A direct correlation is established between the lattice parameter and the dielectric tunability (measured at 3GHz and 3Vμm−1) independently of the parameters used to synthesize the films (oxygen deposition pressure, deposition/crystallization temperature, and W–Al doping level). This correlation is explained in terms of elastic strain effects inside the Ba0.5Sr0.5TiO3 grains. According to this study, a broad tunability can be achieved on low-cost microwave devices based on nonepitaxial BST films provided the internal elastic stress of the film is minimal.
Magnetic trapping induced low temperature phase transition from fcc to fct in pulsed laser deposition of FePt:Al2O3 nanocomposite thin films
Authors: Lin J. J. , Zhang T. , Lee P. , Springham S. V. , Tan T. L. , Rawat R. S. , White T. , Ramanujan R. , Guo J.
Published: August 2007

Fe Pt : Al 2 O 3 nanocomposite thin films have been synthesized by magnetic trapping assisted pulsed laser deposition. The annealing temperature required for phase transition from low Ku fcc-FePt to high Ku fct-FePt is lowered down from about 600°C for conventional pulsed laser deposition (PLD) to 300°C for magnetic trapping assisted PLD. For the sample annealed at 300°C with fct phase FePt nanoparticles, the average nanoparticle size is estimated to be about 8.7±2.1nm, and the magnetic properties are improved which makes it a potentially good candidate for possible applications in high density data storage.
Direct observation of oxygen stabilization in layered ferroelectric Bi3.25La0.75Ti3O12
Authors: Kim Su Jae , Moriyoshi Chikako , Kimura Sayaka , Kuroiwa Yoshihiro , Kato Kenichi , Takata Masaki , Noguchi Yuji , Miyayama Masaru
Published: August 2007

Electron charge density distributions in layered ferroelectrics Bi4Ti3O12 (BiT) and Bi3.25La0.75Ti3O12 (BLT) are investigated by analyzing high-energy synchrotron-radiation powder diffraction data using the maximum entropy method/Rietveld method. BiT shows that chemical bonding resulting from orbital hybridization is established between Bi–O in the perovskite layer only along the a axis, whereas BLT exhibits isotropic chemical bonding of Bi∕La–O with a high electron density both along the a and b axes. High endurance to polarization fatigue reported for BLT films is suggested to originate from the stabilization of oxygen in the perovskite layer due to the isotropic chemical bonding of Bi∕La–O.
Broadband optical amplification in Bi-doped germanium silicate glass
Authors: Zhou Shifeng , Dong Huafang , Zeng Heping , Feng Gaofeng , Yang Hucheng , Zhu Bin , Qiu Jianrong
Published: August 2007

Bi-doped germanium silicate glass is prepared and their optical properties are investigated. The glass sample shows broadband and flat emission characteristics compared with germanate glass. The single-pass optical amplification was measured on a traditional two-wave mixing configuration. Ultrabroadband optical amplification at 1272 and 1560nm is observed simultaneously. The highest gain at 1272nm of germanium silicate glass reaches to 6.73dB excited with single commercially available 980nm laser diode. The glass is promising for optical amplification covering almost all the O, E, S, C, and L bands.
Enhanced luminescence of SrSi2O2N2:Eu2+ phosphors by codoping with Ce3+, Mn2+, and Dy3+ ions
Authors: Liu Ru-Shi , Liu Yu-Huan , Bagkar Nitin C. , Hu Shu-Fen
Published: August 2007

The authors report here the enhanced luminescence properties of SrSi2O2N2 doped with Eu and M (M=Ce, Dy, and Mn). The Eu and Eu, Mn-codoped powders were prepared by a solid state reaction at temperatures between 1400 and 1600°C under H2 (25%)–N2 (75%) atmosphere. The Eu, M-codoped Sr1−x−ySi2N2O2 phosphors have the monoclinic structure with lattice parameters a∼15.6Å, b∼16.2Å, c∼9.4Å, and β∼91°. The phosphors can be efficiently excited in the UV to visible region, making them attractive as conversion phosphors for a light emitting diode application. A green-yellow emission was observed for Eu,M-codoped Sr1−x−ySi2N2O2. The addition of M in the Eu site in SrSi2O2N2 remarkably enhances the luminescent intensity by the factor of 144%, 148%, and 168% for Ce, Dy, and Mn, respectively.
Unique laser-scanning optical microscope for low-temperature imaging and spectroscopy
Authors: Zhang Li , Aite Saliha , Yu Zhonghua
Published: August 2007

Low-temperature optical characterization of single quantum nanostructures can reveal detailed information on structure-dependent properties of these materials. We describe the development of a unique laser-scanning optical microscope capable of low-temperature single molecule/particle imaging and spectroscopy. Making use of the magnification of a microscope objective, the laser- scanning scheme of the present microscope allows for high-repeatability imaging over large sample areas. The microscope is utilized to measure the low-temperature Raman scattering spectra of individual single-walled carbon nanotubes and single molecule fluorescence spectra of conjugated polymers. The developed low-temperature microscope can be applied to study a wide array of nanomaterials at a single particle level.
High mobility solution processed 6,13-bis(triisopropyl-silylethynyl) pentacene organic thin film transistors
Authors: Park Sung Kyu , Jackson Thomas N. , Anthony John E. , Mourey Devin A.
Published: August 2007

Using the small molecule organic semiconductor 6,13-bis(triisopropyl-silylethynyl) pentacene (TIPS-pentacene), the authors have fabricated the solution-processed organic thin film transistors (OTFTs) with carrier mobility >1cm2∕Vs, current on/off ratio greater than 107, and subthreshold slope <0.3V/decade. The high mobility TIPS-pentacene solution-processed films are deposited from high boiling point solvents and show strong molecular ordering including molecular terracing. Film ordering varies substantially for different solvents and film deposition techniques and OTFT mobility correlates well with film ordering.
Confining P diffusion in Si by an As-doped barrier layer
Authors: Bai Lugang , Yu Decai , Lu Guang-Hong , Liu Feng , Wang Q. , Yilmaz Hamza
Published: August 2007

The miniaturization of Si-based devices requires control of doping profile, which makes the understanding of dopant interaction and diffusion in Si critical. The authors have studied the effect of As doping on P diffusion in Si using first-principles calculations. The authors found a form of As-vacancy complex is energetically favorable, allowing As to consume the vacancy so as to prohibit the vacancy-mediated P diffusion. Also, in the vicinity of As, the vacancy-mediated P diffusion barrier is increased, decreasing further the P mobility. The results provide useful guidance for designing As-doped barriers to block P diffusion in Si wafer processing and metal oxide semiconductor field-effect transistor device fabrication.
Quasi-unipolar InGaAs∕InP photodetection for enhanced optical saturation power and maximal bandwidth
Authors: Yoder P. D. , Flynn E. J.
Published: August 2007

The potential to exploit quasi-unipolar charge transport for superior III-V photodetector performance is demonstrated by the growth, fabrication, and characterization of InGaAs∕InP devices suitable for 1.3 and 1.55μm operation. Incomplete electrical depletion of the absorber may be optimized to both balance and reduce the temporal extent of the electrical responses of both electrons and holes to an optical impulse, without penalty to quantum efficiency or necessarily even junction capacitance. The associated transit-time reduction is demonstrated to be considerable. Characterization of devices exhibiting high internal quantum efficiency demonstrates improvements in bandwidth, optical saturation power, and power dissipation.
Effect of Sn doping on the thermoelectric properties of ErNiSb-based p-type half-Heusler compound
Authors: Kawano Kenta , Kurosaki Ken , Sekimoto Takeyuki , Muta Hiroaki , Yamanaka Shinsuke
Published: August 2007

The authors characterized polycrystalline samples of Sn-doped ErNiSb “ErNiSnxSb1−x (x=0, 0.01, 0.03, and 0.05)” to develop p-type half-Heusler thermoelectric materials. All samples prepared in this study exhibited positive Seebeck coefficients. With increasing Sn content x, the carrier concentration increased, leading to decreases in both electrical resistivity (ρ) and the Seebeck coefficient (S). Thermal conductivity (κ) values were at a similar level in all of the compositions. Sn-doping improved the thermoelectric figure of merit ZT(=S2T∕ρ∕κ) of ErNiSb; the maximum ZT value was 0.29 at 669K, obtained in the composition ErNiSn0.01Sb0.99.
Strain-induced interface instability in GaN∕AlN multiple quantum wells
Authors: Nicolay S. , Feltin E. , Carlin J.-F. , Grandjean N. , Nevou L. , Julien F. H. , Schmidbauer M. , Remmele T. , Albrecht M.
Published: August 2007

It is shown that in GaN∕AlN multiple quantum wells (MQWs), strain is a critical parameter for achieving short-wavelength intersubband transitions (ISBTs). This is investigated by comparing GaN∕AlN MQWs grown by metal organic vapor phase epitaxy on either AlN or GaN templates. The GaN∕AlN interface is found to be unstable when pseudomorphically strained onto GaN, in agreement with theory. This effect deeply affects the quantum well potential profile leading to a strong redshift of the ISBT energies.
Importance of screening charge dynamics on polarization switching in polyvinylidene fluoride
Authors: von Seggern H. , Fedosov S. N.
Published: August 2007

The influence of screening dynamics on polarization switching of polyvinylidene fluoride has been investigated theoretically. A phenomenological model that relates released screening charges to the formation of conductivity modified by charge recombination is presented. The interplay of temporal screening charge release and reconstruction modeled through the temporal behavior of conductivity determines decisively the dynamics of polarization switching. Under the assumption that all the screening charges are released instantaneously upon application of a switching field followed by recombination, a fit to experimental polarization switching data over eight orders of magnitude in time is possible.
Spatially resolved electron energy-loss spectroscopy of electron-beam grown and sputtered CoFeB∕MgO∕CoFeB magnetic tunnel junctions
Authors: Cha Judy J. , Read J. C. , Buhrman R. A. , Muller David A.
Published: August 2007

Electron energy-loss spectroscopy at subnanometer resolution is used to investigate CoFeB∕MgO∕CoFeB magnetic tunnel junctions grown by electron-beam evaporation and radio frequency (rf) sputtering before and after annealing. Gap states were observed in the MgO layer for both growth methods although the rf-sputtered MgO layer showed significantly more gap states. Asymmetry in oxygen bonding between the top and bottom CoFeB∕MgO interfaces was also observed. Moreover, significant amounts of diffused B as BOx were observed in the rf-sputtered MgO layer. A Mg underlayer between the MgO layer and the bottom electrode greatly reduced BOx formation in the barrier upon annealing.
Development of nonaqueous polymer gels that exhibit broad temperature performance
Authors: Lenhart Joseph L. , Cole Phillip J. , Unal Burcu , Hedden Ronald
Published: August 2007

While significant work has focused on aqueous hydrogels for biotechnology applications, hydrogels suffer from a limited operating temperature range due to the moderate freezing point and high volatility of water. In this work, a nonaqueous, chemically cross-linked polybutadiene gel has been designed which exhibits stable properties over a temperature range of −60–70°C. A combination of rheology, neutron scattering, and tack adhesion testing was utilized to characterize the gel properties. The methodology employed to design the polybutadiene gel can be generalized to a variety of gel materials and applications.
Structures and piezoelectric properties of (NaKLi)1−x(BiNaBa)xNb1−xTixO3 lead-free ceramics
Authors: Zuo Ruzhong , Ye Chun
Published: August 2007

Lead-free solid solution piezoelectric ceramics (1−x)(Na0.475K0.475Li0.05)NbO3–x(Bi0.48Na0.48Ba0.04)TiO3 (x=0–0.15) have been fabricated by traditional solid state sintering. All compositions studied have pure perovskite structures, showing an orthorhombic-tetragonal phase transition with increasing x. The tetragonality, however, declined with further increasing x. A morphotropic phase boundary (MPB) between orthorhombic and tetragonal ferroelectric phases was identified approximately at x=0.02, leading to enhanced electrical properties of the dielectric constant εr∕εo∼702, the piezoelectric constant d33∼328pC∕N, and the planar electromechanical coupling factor kp ∼48%. The MPB composition has a higher Curie temperature (415°C) than most Pb(Zr,Ti)O3 compositions. These solid solution ceramics look promising as potential lead-free candidate materials.
Plasmonic microzone plate: Superfocusing at visible regime
Authors: Fu Yongqi , Zhou W. , Lim L. E. N. , Du C. L. , Luo X. G.
Published: August 2007

A silver film-based superlens, a plasmonic microzone plate, is put forth for the purpose of superfocusing at visible regime. The numerical analysis results reveal that it has unique focusing characteristics of longer focal length and depth of focus with resolving power beyond diffraction limit in comparison to the conventional zone plates. Working at near field, it increases working distance l at near field from l<λ∕10 to l≈λ∼5λ. This feature makes it a promising superlens to be used as a probe for the optical systems with high resolution imaging and detection as well as feedback control system immune for autofocusing.
Magnetic properties of nanocrystalline Fe82.65Cu1.35SixB16−x alloys (x=–7)
Authors: Ohta Motoki , Yoshizawa Yoshihito
Published: August 2007

The Si content dependences of the magnetic properties of the Fe82.65Cu1.35SixB16−x alloys prepared by melt spinning were studied. The maximum Bs and minimum Hc were observed at around x=2 for the annealed Fe82.65Cu1.35SixB16−x alloys. The Bs and Hc of the annealed Fe82.65Cu1.35Si2B14 alloy were 1.84T and 6.5A∕m, respectively. The average grain size of the bcc Fe nanocrystal in the annealed alloys with x⩽2 was about 20nm, it increased with x at x>2. The annealing temperature range without the precipitation of o-Fe3B expanded with Si content.
Effects of the wave function localization in AlInGaN quaternary alloys
Authors: Wang Fei , Li Shu-Shen , Xia Jian-Bai , Jiang H. X. , Lin J. Y. , Li Jingbo , Wei Su-Huai
Published: August 2007

Using the first-principles band-structure method and the special quasirandom structures approach, the authors have investigated the band structure of random AlxInyGa1−x−yN quaternary alloys. They show that the wave functions of the band edge states are more localized on the InN sites. Consequently, the photoluminescence transition intensity in the alloy is higher than that in GaN. The valence band maximum state of the quaternary alloy is also higher than GaN with the same band gap, indicating that the alloy can be doped more easily as p-type.
SCAPER, a novel cyclin A–interacting protein that regulates cell cycle progression
Authors: Tsang William Y. , Wang Leyu , Chen Zhihong , Sánchez Irma , Dynlacht Brian David
Published: August 2007

Cyclin A/Cdk2 plays an important role during S and G2/M phases of the eukaryotic cell cycle, but the mechanisms by which it regulates cell cycle events are not fully understood. We have biochemically purified and identified SCAPER, a novel protein that specifically interacts with cyclin A/Cdk2 in vivo. Its expression is cell cycle independent, and it associates with cyclin A/Cdk2 at multiple phases of the cell cycle. SCAPER localizes primarily to the endoplasmic reticulum. Ectopic expression of SCAPER sequesters cyclin A from the nucleus and results specifically in an accumulation of cells in M phase of the cell cycle. RNAi-mediated depletion of SCAPER decreases the cytoplasmic pool of cyclin A and delays the G1/S phase transition upon cell cycle re-entry from quiescence. We propose that SCAPER represents a novel cyclin A/Cdk2 regulatory protein that transiently maintains this kinase in the cytoplasm. SCAPER could play a role in distinguishing S phase– from M phase–specific functions of cyclin A/Cdk2.
An in vitro nuclear disassembly system reveals a role for the RanGTPase system and microtubule-dependent steps in nuclear envelope breakdown
Authors: Mühlhäusser Petra , Kutay Ulrike
Published: August 2007

During prophase, vertebrate cells disassemble their nuclear envelope (NE) in the process of NE breakdown (NEBD). We have established an in vitro assay that uses mitotic Xenopus laevis egg extracts and semipermeabilized somatic cells bearing a green fluorescent protein–tagged NE marker to study the molecular requirements underlying the dynamic changes of the NE during NEBD by live microscopy. We applied our in vitro system to analyze the role of the Ran guanosine triphosphatase (GTPase) system in NEBD. Our study shows that high levels of RanGTP affect the dynamics of late steps of NEBD in vitro. Also, inhibition of RanGTP production by RanT24N blocks the dynamic rupture of nuclei, suggesting that the local generation of RanGTP around chromatin may serve as a spatial cue in NEBD. Furthermore, the microtubule-depolymerizing drug nocodazole interferes with late steps of nuclear disassembly in vitro. High resolution live cell imaging reveals that microtubules are involved in the completion of NEBD in vivo by facilitating the efficient removal of membranes from chromatin.
Cells that express MyoD mRNA in the epiblast are stably committed to the skeletal muscle lineage
Authors: Gerhart Jacquelyn , Neely Christine , Elder Justin , Pfautz Jessica , Perlman Jordanna , Narciso Luis , Linask Kersti K. , Knudsen Karen , George-Weinstein Mindy
Published: August 2007

The epiblast of the chick embryo contains cells that express MyoD mRNA but not MyoD protein. We investigated whether MyoD-positive (MyoDpos) epiblast cells are stably committed to the skeletal muscle lineage or whether their fate can be altered in different environments. A small number of MyoDpos epiblast cells were tracked into the heart and nervous system. In these locations, they expressed MyoD mRNA and some synthesized MyoD protein. No MyoDpos epiblast cells differentiated into cardiac muscle or neurons. Similar results were obtained when MyoDpos cells were isolated from the epiblast and microinjected into the precardiac mesoderm or neural plate. In contrast, epiblast cells lacking MyoD differentiated according to their environment. These results demonstrate that the epiblast contains both multipotent cells and a subpopulation of cells that are stably committed to the skeletal muscle lineage before the onset of gastrulation. Stable programming in the epiblast may ensure that MyoDpos cells express similar signaling molecules in a variety of environments.
Barrier to autointegration factor blocks premature cell fusion and maintains adult muscle integrity in C. elegans
Authors: Margalit Ayelet , Neufeld Esther , Feinstein Naomi , Wilson Katherine L. , Podbilewicz Benjamin , Gruenbaum Yosef
Published: August 2007

Barrier to autointegration factor (BAF) binds double-stranded DNA, selected histones, transcription regulators, lamins, and LAP2–emerin–MAN1 (LEM) domain proteins. During early Caenorhabditis elegans embryogenesis, BAF-1 is required to organize chromatin, capture segregated chromosomes within the nascent nuclear envelope, and assemble lamin and LEM domain proteins in reforming nuclei. In this study, we used C. elegans with a homozygous deletion of the baf-1 gene, which survives embryogenesis and larval stages, to report that BAF-1 regulates maturation and survival of the germline, cell migration, vulva formation, and the timing of seam cell fusion. In the seam cells, BAF-1 represses the expression of the EFF-1 fusogen protein, but fusion still occurs in C. elegans lacking both baf-1 and eff-1. This suggests the existence of an eff-1–independent mechanism for cell fusion. BAF-1 is also required to maintain the integrity of specific body wall muscles in adult animals, directly implicating BAF in the mechanism of human muscular dystrophies (laminopathies) caused by mutations in the BAF-binding proteins emerin and lamin A.
Sox9 regulates cell proliferation and is required for Paneth cell differentiation in the intestinal epithelium
Authors: Bastide Pauline , Darido Charbel , Pannequin Julie , Kist Ralf , Robine Sylvie , Marty-Double Christiane , Bibeau Frédéric , Scherer Gerd , Joubert Dominique , Hollande Frédéric , Blache Philippe , Jay Philippe
Published: August 2007

The HMG-box transcription factor Sox9 is expressed in the intestinal epithelium, specifically, in stem/progenitor cells and in Paneth cells. Sox9 expression requires an active β-catenin–Tcf complex, the transcriptional effector of the Wnt pathway. This pathway is critical for numerous aspects of the intestinal epithelium physiopathology, but processes that specify the cell response to such multipotential signals still remain to be identified. We inactivated the Sox9 gene in the intestinal epithelium to analyze its physiological function. Sox9 inactivation affected differentiation throughout the intestinal epithelium, with a disappearance of Paneth cells and a decrease of the goblet cell lineage. Additionally, the morphology of the colon epithelium was severely altered. We detected general hyperplasia and local crypt dysplasia in the intestine, and Wnt pathway target genes were up-regulated. These results highlight the central position of Sox9 as both a transcriptional target and a regulator of the Wnt pathway in the regulation of intestinal epithelium homeostasis.
Systematic analysis of longitudinal serological responses of pigs infected experimentally with African swine fever virus
Authors: Reis Ana Luísa , Parkhouse R. M. E. , Penedos Ana Raquel , Martins Carlos , Leitão Alexandre
Published: August 2007

The protective immune response to African swine fever virus (ASFV) includes both cellular and serological components. In this study, the role of antibodies in the pathogenicity and diagnosis of African swine fever (ASF) was explored. Accordingly, total and Ig isotype antibody responses against the 12 viral proteins previously demonstrated to be the main targets of serological immunity were evaluated in longitudinally collected sera from pigs infected experimentally with the non-pathogenic ASFV/NH/P68 isolate. Strong total IgG antibody responses were observed against viral proteins E183L/p54, K205R/‘unassigned’, A104R/histone-like and B602L/‘unassigned’; therefore, IgM, IgG1 and IgG2 responses to these proteins were also determined. One protein stimulating IgM (K205R) may have practical potential for the detection of recently infected animals. There was a clear trend towards an IgG1 response to all of the proteins. This may reflect a dominant Th2-controlled immune response. In order to identify possible correlations between these serological responses and the pathogenesis of ASF, total IgG responses to the 12 recombinant proteins were compared in asymptomatic and chronically infected animals. For the proteins NP419L/DNA ligase, CP312R, B646L/p73, K196R/thymidine kinase and K205R, the antibody titres were significantly higher in animals developing lesions. One exception was the antibody response to the A104R/histone-like protein, which was higher in asymptomatic than in chronically infected pigs, suggesting that antibodies against this protein might be an indicator of an effective immune response or that this response is somehow involved in protection.
Reprogramming the chiA expression profile of Autographa californica multiple nucleopolyhedrovirus
Authors: Hodgson Jeffrey J. , Arif Basil M. , Krell Peter J.
Published: August 2007

Expression of chiA and v-cath RNA and enzyme activity in wild-type Autographa californica multiple nucleopolyhedrovirus (AcMNPV) was compared with that of recombinant AcMNPV viruses reprogrammed for expression of the endogenous chiA. To establish a baseline for our recombinant AcMNPV studies, we compared, for the first time, the temporal expression profiles of both AcMNPV chiA transcription and translation simultaneously. The rate of intracellular chitinase accumulation during AcMNPV infection followed the same pattern observed for chiA transcription but was delayed by about 6 h. Replacement of 21 nucleotides containing the native late chiA and v-cath promoters with a selectable polh–EGFP cassette was sufficient to eliminate expression of both chiA and v-cath. Viruses were generated that express chiA from either the late p6.9 or very late polh promoters of AcMNPV, replacing the native chiA promoter. There was a marked difference in the temporal chiA transcription profiles from the native, p6.9 and polh promoters, resulting in respective specific activities of chitinase at 48 h p.i. of 62, 160 and 219 mU (mg lysate total protein)−1. Based on temporal analysis of v-cath transcription by Northern blot, AcMNPV v-cath was transcribed from 9 h p.i. in Sf21 cells. However, expression of v-cath RNA or enzyme from a reconstructed v-cath promoter in the chiA-reprogrammed viruses was not detected at 48 h of virus replication. Reprogramming for increased chitinase (and putatively cathepsin) expression with native baculovirus promoters might provide a means for designing environmentally benign biological insecticides.
The CD4+ T-cell response to adenovirus is focused against conserved residues within the hexon protein
Authors: Onion David , Crompton Laura J. , Milligan Donald W. , Moss Paul A. H. , Lee Steven P. , Mautner Vivien
Published: August 2007

Adenovirus is a significant pathogen in immunocompromised patients and is widely utilized as a gene delivery vector, so a detailed understanding of the human immune response to adenovirus infection is critical. This study characterized the adenovirus-specific CD4+T-cell response of healthy donors by incubation with whole virus or with individual hexon and fiber proteins. Adenovirus-specific CD4+T cells averaged 0.26 % of the CD4+T-cell pool and were detectable in all donors. T cells recognizing the highly conserved hexon protein accounted for 0.09 %, whereas no response was observed against the fiber protein. A panel of hexon-specific CD4+T-cell clones was generated and shown to lyse targets infected with adenovirus from different serotypes and species. Three CD4 T-cell epitopes are described, which map to highly conserved regions of the hexon protein.
The Chilo iridescent virus DNA polymerase promoter contains an essential AAAAT motif
Authors: Nalçacioğlu Remziye , Ince Ikbal Agah , Vlak Just M. , Demirbağ Zihni , van Oers Monique M.
Published: August 2007

The delayed-early DNA polymerase promoter of Chilo iridescent virus (CIV), officially known as Invertebrate iridescent virus, was fine mapped by constructing a series of increasing deletions and by introducing point mutations. The effects of these mutations were examined in a luciferase reporter gene system using Bombyx mori cells transfected with promoter constructs and infected with CIV. When the size of the upstream element was reduced from position −19 to −15, relative to the transcriptional start site, the luciferase activity was reduced to almost zero. Point mutations showed that each of the 5 nt (AAAAT) located between –19 and –15 were equally essential for promoter activity. Mutations at individual bases around the transcription initiation site showed that the promoter extended until position −2 upstream of the transcription start site. South-Western analysis showed that a protein of approximately 100 kDa interacted with the −19 nt promoter fragment in CIV-infected cells. This binding did not occur with a point mutant that lacked promoter activity. The AAAAT motif was also found in the DNA polymerase promoter region of other iridoviruses and in other putative CIV delayed-early genes.
Anti-IE1 CD4+ T-cell clones kill peptide-pulsed, but not human cytomegalovirus-infected, target cells
Authors: Delmas Sandra , Brousset Pierre , Clément Danièle , Le Roy Emmanuelle , Davignon Jean-Luc
Published: August 2007

Cellular immunity plays a major role in the control of human cytomegalovirus (HCMV) infection. CD4+T lymphocytes have been shown to contribute to this function but their precise role is a matter of debate. Although CD4+T cells have been shown to kill target cells through the perforin/granzyme pathway, whether HCMV-specific CD4+T cells are capable of killing HCMV-infected targets has not yet been documented. In the present paper, we have taken advantage of well established cellular reagents to address this issue. Human CD4+T-cell clones specific for the major immediate-early protein IE1 were shown to perform perforin-based cytotoxicity against peptide-pulsed targets. However, when tested on infected anitgen presenting cell targets, cytotoxicity was not detectable, although gamma interferon (IFN-γ) production was significant. Furthermore, cytotoxicity against peptide-pulsed targets was inhibited by HCMV infection, whereas IFN-γproduction was not modified, suggesting that antigen processing was not altered. Remarkably, degranulation of CD4+T cells in the presence of infected targets was significant. Together, our data suggest that impaired cytotoxicity is not due to failure to recognize infected targets but rather to a mechanism specifically related to cytotoxicity.
Virus distribution of the attenuated MVA and NYVAC poxvirus strains in mice
Authors: Gómez Carmen Elena , Nájera José Luis , Domingo-Gil Elena , Ochoa-Callejero Laura , González-Aseguinolaza Gloria , Esteban Mariano
Published: August 2007

Recombinant vaccinia viruses based on the attenuated NYVAC and MVA strains are promising vaccine candidates against a broad spectrum of diseases. Whilst these vectors are safe and immunogenic in animals and humans, little is known about their comparative behaviour in vivo. In this investigation, a head-to-head analysis was carried out of virus dissemination in mice inoculated by the mucosal or systemic route with replication-competent (WRluc) and attenuated recombinant (MVAluc and NYVACluc) viruses expressing the luciferase gene. Bioluminescence imaging showed that, in contrast to WRluc, the attenuated recombinants expressed the reporter gene transiently, with MVAluc expression limited to the first 24 h and NYVACluc giving a longer signal, up to 72 h post-infection, for most of the routes assayed. Moreover, luciferase levels in MVAluc-infected tissues peaked earlier than those in tissues infected by NYVACluc. These findings may be of immunological relevance when these vectors are used as recombinant vaccines.
Mapping to completeness and transplantation of a group-specific, discontinuous, neutralizing epitope in the envelope protein of dengue virus
Authors: Lisova Olesia , Hardy Florence , Petit Vincent , Bedouelle Hugues
Published: August 2007

Dengue is caused by a taxonomic group of four viruses, dengue virus types 1–4 (DENV1–DENV4). A molecular understanding of the antibody-mediated protection against this disease is critical to design safe vaccines and therapeutics. Here, the energetic epitope of antibody mAb4E11, which neutralizes the four serotypes of DENV but no other flavivirus, and binds domain 3 (ED3) of their envelope glycoprotein, was characterized. Alanine-scanning mutagenesis of the ED3 domain from serotype DENV1 was performed and the affinities between the mutant domains and the Fab fragment of mAb4E11 were measured. The epitope residues (307–312, 387, 389 and 391) were at the edges of two distinct β-sheets. Four residues constituted hot spots of binding energy. They were aliphatic and contributed to form a hydrophobic pocket (Leu308, Leu389), or were positively charged (Lys307, Lys310). They may bind the diversity residues of mAb4E11, H-Trp96-Glu97. Remarkably, cyclic residues occupy and block the hydrophobic pocket in all unrelated flaviviruses. Transplanting the epitope from the ED3 domain of DENV into those of other flaviviruses restored affinity. The epitope straddles residues of ED3 that are involved in virulence, e.g. Asn/Asp390. These results define the epitope of mAb4E11 as an antigenic signature of the DENV group and suggest mechanisms for its neutralization potency.
Cis-acting elements in the antigenomic promoter of Nipah virus
Authors: Walpita Pramila , Peters Clarence J.
Published: August 2007

Genome synthesis in paramyxoviruses, including Nipah virus (NiV), is controlled by sequence elements that reside in the non-coding nucleotides at the 5′-trailer (3′-antigenomic) end that make up the antigenomic promoter (AGP). Using a chloramphenicol acetyl transferase-based plasmid-driven minigenome system, the terminal 96 nt of NiV AGP were first mutagenized in blocks of three hexamers to enable broad mapping of the minigenome functional regions. This was followed by further dissection of these functional regions to define the cis-acting elements contained therein. Results based on RNA analysis and reporter gene activity identified a bipartite promoter structure similar to that seen in related viruses, but with some distinct differences: in NiV, each of the two discrete replication control elements was bimodal, characterized by a critical conserved region (nt 1–12 and 79–91) and a contiguous non-conserved region (nt 13–36 and 73–78), which appeared less important. The regulatory role of these less critical regions was underscored by the use of a two-step mutation strategy, which revealed the additive detrimental effect of substitutions in this part of the terminal element. The structure and sequence characteristics of the internal control element was also different: it involved four contiguous hexamers, and the region encompassing three of these (nt 79–96, corresponding to hexamers 14, 15 and 16), although analogous in position to the equivalent element in the Sendai virus AGP, was characterized by the distinct 5′-(GNNNUG)14–15(GNNNNN)16 motif.
Adaptation of two flaviviruses results in differences in genetic heterogeneity and virus adaptability
Authors: Ciota Alexander T. , Lovelace Amy O. , Jones Susan A. , Payne Anne , Kramer Laura D.
Published: August 2007

West Nile virus (WNV) is a mosquito-borne flavivirus that was first introduced into the USA in the New York City area in 1999. Since its introduction, WNV has steadily increased both its host and geographical ranges. Outbreaks of the closely related flavivirus, St. Louis encephalitis virus (SLEV), occur in the USA periodically, but levels of activity and host range are more restricted than those of WNV. Understanding the selective pressures that drive arbovirus adaptation and evolution in their disparate mosquito and avian hosts is crucial to predicting their ability to persist and re-emerge. Here, we evaluated thein vivophenotypes of mosquito cell-adapted WNV and SLEV. Results indicated thatin vitroadaptations did not translate toin vivoadaptations for either virus, yet SLEV displayed attenuated growth in both mosquitoes and chickens, while WNV generally did not.In vitrogrowth analyses also indicated that WNV adaptations could be generalized to cell cultures derived from other mosquito species, while SLEV could not. Analysis of genetic diversity for passaged SLEV revealed a highly homogeneous population that differed significantly from previous results of high levels of diversity in WNV. We hypothesize that this difference in genetic diversity is directly related to the viruses' success in new and changing environments in the laboratory and that differences in a viruses' ability to produce and maintain heterogeneous populations in nature may in some instances explain the variable levels of success seen among arboviruses.
Local immune response to respiratory syncytial virus infection is diminished in senescence-accelerated mice
Authors: Liu Beixing , Kimura Yoshinobu
Published: August 2007

The effect of ageing on the local defence system against respiratory syncytial virus (RSV) infection was investigated using an aged mouse model of the senescence-accelerated mouse (SAM) strain P1. Following intranasal infection with RSV, SAM-P1 mice showed a marked loss in weight, with elevated virus growth in the lungs and prolonged virus shedding. The increased susceptibility to RSV infection was associated mainly with diminished cellular immunity by local virus-specific cytotoxic T lymphocytes and natural killer cells. The deficiency in cellular immune responses was due to a lack of clonal expansion of CD4+and CD8+T lymphocytes, together with an imbalance of T-helper type 1 (Th1)/Th2 cytokine production in the respiratory tract, including the lungs. Furthermore, the production of virus-specific local IgA antibody was restrained. Prolonged virus loading in the lungs of SAM-P1 mice caused a massive infiltration of CD16+/32+inflammatory cells, which was one factor responsible for severe pneumonia. The adoptive transfer of immune-competent spleen cells achieved an appreciable protection for SAM-P1 mice against RSV challenge infection. These results suggested that age-related immune dysfunction, especially defects in cellular immune responses, accounts for the increased morbidity and mortality in RSV infection of the elderly.
Modifications of the PSAP region of the matrix protein lead to attenuation of vesicular stomatitis virus in vitro and in vivo
Authors: Irie Takashi , Carnero Elena , Okumura Atsushi , García-Sastre Adolfo , Harty Ronald N.
Published: August 2007

The matrix (M) protein of vesicular stomatitis virus (VSV) is a multi-functional protein involved in virus assembly, budding and pathogenesis. The 24PPPY27 late (L) domain of the M protein plays a key role in virus budding, whereas amino acids downstream of the PPPY motif contribute to host protein shut-off and pathogenesis. Using a panel of 37PSAP40 recombinant viruses, it has been demonstrated previously that the PSAP region of M does not possess L-domain activity similar to that of PPPY in BHK-21 cells. This study reports the unanticipated finding that these PSAP recombinants were attenuated in cell culture and in mice compared with control viruses. Indeed, PSAP recombinant viruses exhibited a small-plaque phenotype, reduced CPE, reduced levels of activated caspase-3, enhanced production of IFN-β and reduced titres in the lungs and brains of infected mice. In particular, recombinant virus M6PY>A4-R34E was the most severely attenuated, exhibiting little or no CPE in cell culture and undetectable titres in the lungs and brains of infected mice. These findings indicate an important role for the PSAP region (aa 33–44) of the M protein in the pathology of VSV infection and may have implications for the development of VSV as a vaccine and/or oncolytic vector.
Reduction of vector gene expression increases foreign antigen-specific CD8+ T-cell priming
Authors: Fischer Matthew A. , Tscharke David C. , Donohue Keri B. , Truckenmiller Mary E. , Norbury Christopher C.
Published: August 2007

Viral vectors have been shown to induce protective CD8+T-cell populations in animal models, but significant obstacles remain to their widespread use for human vaccination. One such obstacle is immunodominance, where the CD8+T-cell response to a vector can suppress the desired CD8+T-cell response to a recombinantly encoded antigen. To overcome this hurdle, we broadly reduced vector-specific gene expression. We treated a recombinant vaccinia virus, encoding antigen as a minimal peptide determinant (8–10 aa), with psoralen and short-wave UV light. The resulting virus induced 66 % fewer vector-specific immunodominant CD8+T cells, allowing thein vivoinduction of an increased number of CD8+T cells specific for the recombinant antigen.
Abstractions and Metaphysical Politics
Authors: Taylor Simon , Percy Martyn
Published: August 2007

Books reviewed in this article:

David Toole, Waiting for Godot in Sarajevo: Theological Reflections on Nihilism, Tragedy and Apocalypse
Reading the Bible as Americans
Authors: Lindström Fredrik
Published: August 2007

The New Interpreter's Bible: Volume One, L. E. Keck and others (eds)
Two Radical Jews
Authors: Wright N. T.
Published: August 2007

A Radical Jew: Paul and the Politics of Identity, Daniel Boyarin
Freeing the Spirit
Authors: Scott Peter
Published: August 2007

Fragments of the Spirit: Nature, Violence nd the Renewal of Creation, Mark I. Wallace
The Font of all Wisdom
Authors: Else Steve
Published: August 2007

Can Religion be Explained Away? D. Z. Phillips (ed.)

Atheism and Theism, J. J.C. Smart and J. J. Haldane

Arguing for Atheism: An Introduction to the Philosophy of Religion, Robin Le Poidevin
What's [Not] New in Trinitarian Theology
Authors: Cunningham David S.
Published: August 2007

The Christian Doctrine of God: One Being Three Persons, Thomas F. Torrance, T. & T. Clark

The Father's Spirit of Sonship: Reconceiving the Trinity, Thomas G. Weinandy, T. & T. Clark

Trinitarian Theology Today: Essays on Divine Being and Act, Christoph Schwöbel (ed.), T. & T. Clark
RECENT BOOKS IN…NEW TESTAMENT STUDIES
Authors: Goodacre Mark
Published: August 2007

Exploring the Gospel of John: Essays in Honor of D. Moody Smith, R. Alan Culpepper and C. Clifton Black (eds)

Jesus in the Nag Hammadi Writings, Majella Franzmann, T. & T. Clark

Renewal through Suffering: A Study of II Corinthians, A. E. Harvey, T. & T. Clark

The Social Ethos of the Corinthian Correspondence: Interests and Ideology from I Corinthians to I Clement, David G. Horrell, T. & T. Clark

Jesus Matters: 150 Years of Research, C. J. den Heyer

Who Did Jesus Think He Was?, J. C. O'Neill, E. J. Brill

Scripture and Discernment: Decision Making in the Church, Luke T. Johnson

The Human Condition: Anthropology in the Teachings of Jesus, Paul and John, Udo Schnelle, T. & T. Clark
On Trinitarian Ecclesiologies
Authors: D'Costa Gavin
Published: August 2007

After Our Likeness. The Church as the Image of the Trinity, Miroslav Volf, Eerdmans 1998
On Reading Durkheim
Authors: Stringer Martin D.
Published: August 2007

On Durkheim's Elementary Forms of Religious Life, N.J. Allen, W.S.F. Pickering and W. Watts Miller (eds)
SOCIOLOGISM IN PHILOSOPHY OF SCIENCE*
Authors: Agassi Joseph
Published: August 2007

In a nutshell, the present essay claims this: First, the classical problem of knowledge has recently shifted from, How do I know? to, How do we know?–from psychology to sociology. As a phenomenological matter this is a great improvement, as a solution to the problem of rationality it is erroneous and immoral. The problem, (Why) should I act, believe, etc., this or that? is answered: You should do so on the authority of your reason. But change the problem of rationality in accord with the change in the problem of knowledge, and ask, (Why) should we–rather than I–act or believe as we do? and the answer is clear: We should act and believe as we do, because our society is as it is, and should be as it is. This is clearly the same as, we should because we should. Not very enlightening.

Sociologism appears as the authoritarian solution to the problem of rationality in works of Polanyi and Kuhn; a variant of it appears as a liberal theory in the studies of Popper and his former students who, however, do not offer any positive theory of what to believe or do; rather, they offer a negative theory of what to reject. They view this as a better solution to the problem of rationality, if not even a better formulation of it (not what and why should I/we etc., but what and why should I/we not etc.).
REVIEWS
Authors: GIRILL T. R.
Published: August 2007

I. Lakatos and A. Musgrave(eds.). Criticism and the Growth of Knowledge
THE PARADOX OF COGNITIVE RELATIVISM REVISITED: A Reply to Jack W. Meiland
Authors: BEACH EDWARD
Published: August 2007

EDITORS NOTE: Typographical corrections of page proofs were accidentally left out of Dr. Beach's article, which appeared in the January issue of this volume. The omission diminishes the value of the article; and the Editor apologizes for the oversight to Dr. Beach and the readers of Metaphilosophy. A typographically correct version is given below.
RORTY'S NEW MYTH OF THE GIVEN
Authors: GOLDMAN MICHAEL
Published: August 2007

But the dangers to abnormal discourse do not come from science or naturalistic philosophy. They come from the scarcity of food and from the secret police. Given leisure and libraries, the conversation which Plato began will not end in self‐objedification ‐ not because aspects of the world, or of human beings, escape being objects of scientific inquiry, but simply because free and leisured conversation generates abnormal discourse as the sparks fly upward (Rorty 1979, 389).
TOWARDS A POSTMODERN CONCEPTION OF METAPHYSICS: ON THE GENEALOGY AND SUCCESSOR DISCIPLINES OF MODERN PHILOSOPHY
Authors: PHILIPSE HERMAN
Published: August 2007

Postmodernism in philosophy holds that traditional philosophy has come (or should come) to an end, and that it must be succeeded by something else, such as “thinking” (Heidegger), empirical science (Quine), linguistic therapy (Wittgenstein), or an “attempt to prevent the conversation of the West from attaining the secure path of science” (Rorty). Clearly, the claim to be postmodern presupposes a view of traditional philosophy, of its characteristics, and of its genesis. In this essay, such a view will be developed, and its consequences for our conception of philosophy will be discussed. The view defended here is different from those of Heidegger and Rorty. For ease of exposition the discussion will refer to Rorty's Philosophy and the Mirror of Nature.
BOOKS Review
Authors: Gavin William J. , Grier Philip T.
Published: August 2007

Legal Philosophies of Russian Liberalism. By Andrzej Walicki.

A History of Russian Philosophy, Edited by Valery A. Kuvakin.