bluuebunny/crossref_metadata_2025_split huggingface dataset:
Systemic inactivation of Hs6st1 in mice is associated with late postnatal mortality without major defects in organogenesis
Authors: Izvolsky Konstantin I. , Lu Jining , Martin Greg , Albrecht Kenneth H. , Cardoso Wellington V. 
Published: January 2008

AbstractHeparan sulfate (HS) proteoglycans modulate the biological activity of a number of growth factors in development, homeostasis, and cancer. Specific modifications of HS chains by HS biosynthetic enzymes have been implicated in growth factor signaling in multiple aspects of organogenesis. Although the role of HS 6‐O‐sulfotransferases has been described in processes such as trachea formation in Drosophila and vasculogenesis in zebrafish, little is known about how HS 6‐O‐sulfotransferases (Hs6st1‐3 in mice) influence mouse development. To address this issue, we generated a conditionally mutant Hs6st1 mouse line and then generated mice with systemic inactivation of Hs6st1. Hs6st1‐null pups were viable and grossly normal at birth. The lack of obvious abnormalities in lung, liver, and kidney, which express high levels of Hs6st1 during development, suggests that at least during embryonic life, the loss of Hs6st1 function may be compensated for by mechanisms involving other HS modifying enzymes. During early adulthood, however, Hs6st1‐null mice failed to thrive and exhibited growth retardation, body weight loss, enlargement of airspaces in the lung and, in some cases, lethality. Our results suggest a potentially critical role for HS 6‐O sulfation by Hs6st1 in postnatal processes. genesis 46:8–18, 2008. © 2008 Wiley‐Liss, Inc.
CD8– dendritic cells preferentially cross‐present Saccharomyces cerevisiae antigens
Authors: Backer Ronald , van Leeuwen Fred , Kraal Georg , den Haan Joke M. M. 
Published: January 2008

AbstractMouse splenic dendritic cell (DC) subsets possess distinct antigen‐presentation abilities. CD8+ DC are specialized in cross‐presentation of antigens to CD8+ T cells, whereas CD8– DC are more efficient in antigen presentation to CD4+ T cells. In this study, we examined the capacity of CD8+ and CD8– DC subsets to present fungal antigens in MHC class I and II molecules to CD8+ and CD4+ T cells, respectively. We used ovalbumin‐expressing Saccharomyces cerevisiae (yeast‐OVA) as a fungal model system. Both CD8+ and CD8– DC subsets phagocytosed yeast in equal amounts and uptake was mediated via dectin‐1. In addition, both DC subsets induced similar OVA‐specific CD4+ T cell proliferation after incubation with yeast‐OVA. However, the induction of OVA‐specific CD8+ T cell activation was largely restricted to the CD8– DC subset. Furthermore, only CD8– DC produced cytokines such as IL‐10 and TNF‐α and increased IL‐23p19 and IL‐23p40 mRNA levels in response to yeast. Our results strongly suggest that DC subsets have different functions in the elicitation of adaptive immune responses in vivo.
Interferon regulatory factor 7‐mediated responses are defective in cord blood plasmacytoid dendritic cells
Authors: Danis Bénédicte , George Thaddeus C. , Goriely Stanislas , Dutta Binita , Renneson Joëlle , Gatto Laurent , Fitzgerald‐Bocarsly Patricia , Marchant Arnaud , Goldman Michel , Willems Fabienne , De Wit Dominique 
Published: January 2008

AbstractPlasmacytoid dendritic cells (pDC) are specialized in massive production of type I interferons (IFN) upon viral infections. Activation of IFN regulatory factor (IRF)‐7 is critically required for the synthesis of type I IFN in pDC. IRF‐7 is highly expressed by resting pDC and translocates into the nucleus to initiate type I IFN transcription. In a previous work, we observed an impaired IFN‐α production in enriched cord blood pDC following a TLR9 stimulation using CpG oligonucleotides. Herein, we show that highly purified pDC from cord blood exhibit a profound defect in their capacity to produce IFN‐α/β in response to TLR9 as well as to TLR7 ligation or human CMV or HSV‐1 exposure. Microarray experiments indicate that expression of the majority of type I IFN subtypes induced by a TLR7 agonist is reduced in cord blood pDC. We next demonstrated a reduced nuclear translocation of IRF‐7 in cord blood pDC following CpG and HSV stimulation as compared to adult pDC. We conclude that impaired IRF‐7 translocation in cord blood pDC is associated with defective expression of type I IFN genes. Our data provide a molecular understanding for the decreased ability of cord blood pDC to produce type I IFN upon viral stimulation.
Systemic autoimmunity in BAFF‐R‐mutant A/WySnJ strain mice
Authors: Mayne Christopher G. , Amanna Ian J. , Nashold Faye E. , Hayes Colleen E. 
Published: January 2008

AbstractSystemic lupus erythematosis is an autoimmune disease of unknown etiology. Lupus pathology is thought to reflect autoantibody‐mediated damage due to a failure of B lymphocyte tolerance. Since excessive B cell‐activating factor belonging to the TNF family (BAFF) expression correlates with human and murine lupus, and BAFF signals B cell survival through BAFF‐R, it is believed that excessive BAFF‐R signaling can subvert B cell tolerance and facilitate lupus development. Here we report the unexpected finding that BAFF‐R‐mutant A/WySnJ mice develop a lupus‐like syndrome. These mice carry the B cell maturation defect‐1 (Bcmd‐1) mutant allele of the Baffr gene. Bcmd‐1 causes premature B cell death and profound B cell deficiency. Despite having 90% fewer splenic B cells than normal mice, A/WySnJ mice had an 18‐fold increased frequency of splenocytes secreting IgM antibodies to dsDNA, and increased amounts of circulating IgM and IgG to dsDNA by 9 months of age. By age 11 months, most A/WySnJ mice displayed renal pathology characteristic of lupus, including proteinuria as well as periodic acid‐Schiff‐positive deposits and glomerular capillary bed destruction. Importantly, we genetically linked this autoimmunity to Bcmd‐1, since congenic AW.Baffr+/+ mice carrying a wild‐type allele developed none of these phenotypes. Our data provide the first evidence linking altered BAFF‐R signaling to the development of B cell‐mediated autoimmunity.
Dynamic regulation of c‐Myc proto‐oncogene expression during lymphocyte development revealed by a GFP‐c‐Myc knock‐in mouse
Authors: Huang Ching‐Yu , Bredemeyer Andrea L. , Walker Laura M. , Bassing Craig H. , Sleckman Barry P. 
Published: January 2008

Abstractc‐Myc induces widely varying cellular effects, including cell proliferation and cell death. These different cellular effects are determined, in part, by c‐Myc protein expression levels, which are regulated through several transcriptional and post‐transcriptional pathways. c‐Myc transcripts can be detected in cells at all stages of B and T lymphocyte development. However, little is known about c‐Myc protein expression, and how it varies, in developing lymphocytes. Here mice have been generated in which the endogenous c‐Myc locus has been modified (c‐MycG) so that it encodes a GFP‐c‐Myc fusion protein. c‐MycG/G mice are viable, appear normal and exhibit grossly normal lymphocyte development. Flow cytometric analyses revealed significant heterogeneity in c‐Myc protein expression levels in developing c‐MycG/G B and T lymphocytes. GFP‐c‐Myc expression levels were highest in proliferating lymphocytes, suggesting that c‐Myc up‐regulation is important for promoting lymphocyte cell division, and demonstrating that GFP‐c‐Myc expression is a marker of proliferating lymphocytes in vivo.
A Simple Non‐Aqueous Route to Anatase TiO2
Authors: Jiang Dong , Xu Yao , Hou Bo , Wu Dong , Sun Yuhan 
Published: January 2008

AbstractHigh‐yield nanocrystalline TiO2 was successfully synthesised using a simple one‐step procedure in a non‐aqueous system. The synthesis was carried out in a teflon‐lined autoclave at a temperature as low as 100 °C using titanium n‐butoxide (TB) and acetic acid (AcOH) as starting materials without any co‐solvent/additive. The thus formed TiO2 was highly crystallised anatase TiO2. The possible formation mechanism was also proposed based on the FTIR spectra recorded during the various reaction stages. The synthetic method explored in this study might contribute to the preparation of other metal oxides.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
A Versatile and Low‐Toxicity Route for the Production of Electroceramic Oxide Nanopowders
Authors: Morata Alejandro , Chesnaud Anthony , Tarancón Alberto , Estradé Sonia , Peiró Francesca , Morante Joan‐Ramon , Dezanneau Guilhem 
Published: January 2008

AbstractAn alternative route to acrylamide gel polymerisation is presented for the preparation of oxide nanopowders. Within this method, cations first dissolved in an aqueous solution are subsequently trapped inside a 3D chelating gel beforefast‐drying, which leads to a stable precursor. In this study, we have prepared compositions corresponding to a wide range of state‐of‐the‐art fuel cells materials such as: Zr0.85Y0.15O1.875, Ce0.9Gd0.1O1.95, Nd1.95NiO4+x, GdBaCo2O5+x, Ba0.5Sr0.5Co0.8Fe0.2O3–x and La0.75Sr0.25Cr0.5Mn0.5O3. Thermogravimetry and differential thermal analysis studies have been performed to determine the best calcination conditions. After calcination, the resulting powders have been characterised by X‐ray diffraction, FEG‐scanning electron microscopy and TEM. The synthesised powders are of nanometric crystallite size and have flake‐like aggregates; pure phases are obtained at low temperature. We made this method more attractive by using a nontoxic polymer and a nonexplosive initiator. This route allows the easy preparation of more than tens of grams of nanometric powders in one batch. Finally, since this process is largely independent of the formula of the compound, it can easily be extended to other kinds of oxides such as ferroelectric, CMR (colossal magnetoresistance) or gas sensor compounds.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Syntheses, Structures, and Characterizations of Two New Indium(III) Compounds from 1D ···In–OH–In–OH··· Chains and Pyridinedicarboxylic Ligands
Authors: Guo Zhengang , Li Yafeng , Yuan Wenbing , Zhu Xiandong , Li Xinfa , Cao Rong 
Published: January 2008

AbstractThe self‐assembly of In2O3 with 2,5‐pyridinedicarboxylic acid (2,5‐H2PDC) and 3,5‐pyridinedicarboxylic acid (3,5‐H2PDC) generates two hybrid inorganic–organic compounds [In(OH)(2,5‐PDC)]n (1) and [In2(OH)2(3,5‐PDC)2(H2O)]n (2), respectively. The two compounds have been characterized by IR, XRPD, elemental analysis, and photoluminescent studies. The structure of 1 consists of corner‐sharing InNO5 octahedra and 2,5‐PDC ligands to form 2D frameworks with thermal stability up to ca. 347 °C. The 3D framework of 2 contains corner‐sharing InN2O4 octahedra and InO7 decahedra with a 406 nm emission at 77 K. Both of the compounds possess similar one‐dimensional ···In–OH–In–OH··· inorganic chains.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Sol–gel processing of anti‐inflammatory entrapment in silica, release kinetics, and bioactivity
Authors: Catauro M. , Melisi D. , Curcio A. , Rimoli M.G. 
Published: January 2008

AbstractControlled and local drug‐delivery systems for anti‐inflammatory agents are drawing increasing attention for possible pharmaceutical and biomedical applications, because of their extended therapeutic effect and reduced side effects. A single‐step sol–gel process was used to precipitate silica microspheres containing Ketoprofen, Indomethacin, Ketorolac tris salt, or Triamcinolone acetonide, for controlled drug delivery applications. The amorphous nature of the gels was ascertained by X‐ray diffraction analysis. Release kinetics in a simulated body fluid (SBF) has been subsequently investigated. The amount of drug released has been detected by UV–vis spectroscopy. The pure anti‐inflammatory agent exhibited linear release with time, while sol–gel silica‐entrapped drugs were released with a logarithmic time dependence, starting with an initial burst effect followed by a gradual decrease. Finally, SEM micrography and EDS analysis showed the formation of a hydroxyapatite layer on the surface of the samples soaked in SBF. All the materials showed good release and therefore could be used as drug‐delivery systems. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Rational identification of a novel peptide for targeting nanocarriers to 9L glioma
Authors: Agarwal Abhiruchi , Jaye David L. , Giegerman Cissy M. , Bellamkonda Ravi V. 
Published: January 2008

AbstractTraditional therapies for high grade gliomas are limited in part by collateral damage to normal tissues. Selective delivery of therapies to tumors is, therefore, needed. Here, we report that liposomal nanocarriers coated with a novel oligopeptide enhance uptake by 9L gliosarcoma. A targeting nine amino acid peptide sequence (RSI) was identified by differential panning of random peptide phage display libraries on 9L cells and rat blood cells and plasma. Peptides were coupled to the surface of liposomal nanocarriers which were subsequently loaded with doxorubicin. The ability of RSI coated liposomes to facilitate drug uptake and cytotoxicity was compared with conventional liposomal nanocarriers and controls. In addition, plasma clearance profiles of the RSI peptide coupled liposomal nanocarriers were evaluated in adult immuno‐competent rats. RSI peptide‐coupled liposomal nanocarriers enhanced drug uptake by 9L cells by 500% compared with conventional liposomal nanocarriers, and significantly increased cytotoxicity. The plasma half‐lives confirmed that the presence of the RSI peptide on the liposomal nanocarriers did not compromise circulation time in the blood in comparison with Stealth liposomal nanocarriers. These data suggest that phage‐identified oligopeptides could lead to the development of new tumor selective nanocarriers. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
High levels of HIF‐2α highlight an immature neural crest‐like neuroblastoma cell cohort located in a perivascular niche
Authors: Pietras A , Gisselsson D , Øra I , Noguera R , Beckman S , Navarro S , Påhlman S 
Published: January 2008

AbstractHigh HIF‐2α protein levels in the sympathetic nervous system‐derived childhood tumour neuroblastoma as well as immature phenotype correlate to unfavourable outcome. Here we show that a small subset of perivascularly located, strongly HIF‐2α‐positive tumour cells (MYCN amplified) lacks expression of differentiation markers, but expresses neural crest and early sympathetic progenitor marker genes such as Notch‐1, HES‐1, c‐Kit, dHAND, and vimentin. HIF‐2α‐ and CD68‐positive tumour‐associated macrophages were frequently found close to the immature and HIF‐2α‐positive neuroblastoma cells and as VEGF levels are high in the perivascular niche, we hypothesize that neuroblastoma neural crest‐like cells and macrophages cooperate to facilitate angiogenesis and thereby contribute to the aggressive neuroblastoma phenotype. Copyright © 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Crystal lattice defects in MBE grown Si layers highly doped with Er
Authors: Zakharov N. D. , Werner P. , Vdovin V. I. , Denisov D. V. , Kyutt R. N. , Sobolev N. A. 
Published: January 2008

AbstractThe structure of Si:Er layers grown by MBE on Si(001) substrates was investigated by transmission electron microscopy. We studied the dependence of the layer structure on the erbium concentration [Er] (8 × 1018 – 4 × 1019 cm–3) as well as the epitaxial growth temperature (400–700 °C). In general, ErSi2 platelets and spherical metallic precipitates are formed during the epitaxial growth through the layer and in the near‐interface region, respectively. For [Er] ≥2 × 1019 cm–3, an oscillation of platelet density with periodicity approximately 200–250 nm was observed. A new type of complex structural defect was observed in a specimen with [Er] = 4 × 1019 cm–3. In the layers grown at 400 °C, complexes of extended defects consisting of partial dislocations, stacking faults and twins are generated. The formation of silicides and Er precipitates is accompanied by emission of vacancies, which leads to the formation of pores in the layer. A high concentration of vacancies should also result in formation of V–V and V–Er complexes. The presence of these point‐defect complexes can explain the appearance of deep acceptor levels with an activation energy of 360 meV, which can be responsible for nonradiative paths. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Local disorder influence on electrical phenomena of pure and Ba‐doped Pb5Ge3O11 crystals
Authors: Molak A. , Talik E. , Pawełczyk M. , Adamiec M. , Koralewski M. 
Published: January 2008

AbstractThe relation between chemical composition, crystal structure and electrical features of lead germanate, (Pb5–x Bax)Ge3O11, pure and doped with Ba (x = 0, 0.10, 0.25) was studied. The O deficiency and GeO2 precipitation was found in the crystals studied. In the case of the Ba‐doped crystals, the XPS lines width (FWHM) variation suggests structural local disorder. The valence band is placed near 3 eV and it shows an exponential tail, which is ascribed to existence of energy levels correlated to defects. Both the valence band edge shift and the degree of disorder deduced from the change in the XPS lines width vary non‐linearly with the concentration of the Ba ions. The ac conductivity activation energy values Ea = 0.55–0.85 eV indicate electric conductivity of lead germanate is determined by local energy levels originated from point defects. The analysis of the imaginary part of the electric modulus M ″(T, f) exhibited the electronic relaxation process related to electric conductivity, for which the activation energy EM = 0.63–0.72 eV, and the characteristic times τ0 of the order of 10–13 s were evaluated. The crystal structure parameters and several of the electrical conduction parameters exhibit non‐monotonic dependence on the Ba concentration. It was deduced that Ba ions contributed to the mentioned phenomena by two opposite mechanisms. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Hartree–Fock interactions in the integer quantum Hall effect
Authors: Römer Rudolf A. , Sohrmann Christoph 
Published: January 2008

AbstractWe report on numerical studies into the interplay of disorder and electron–electron interactions within the integer quantum Hall regime, where the presence of a strong magnetic field and two‐dimensional confinement of the electronic system profoundly affects thermodynamic and transport properties. We emphasise the behaviour of the electronic compressibility, the local density of states, and the Kubo conductivity. Our treatment of the electron–electron interactions relies on the Hartree‐Fock approximation so as to achieve system sizes comparable to experimental situations. Our results clearly exhibit manifestations of various interaction‐mediated features, such as non‐linear screening, local charging, and g ‐factor enhancement, implying the inadequacy of independent‐particle models for comparison with experimental results. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Quantum Hall effects in normal and superconducting systems: localization and multifractality
Authors: Evers Ferdinand , Mildenberger Achim , Mirlin Alexander D. 
Published: January 2008

AbstractWe study quantum phases and localization–delocalization transitions between these phases in three types of quantum Hall effects. These include the conventional integer quantum Hall effect, as well as its counterparts taking place in super‐ conducting systems: spin quantum Hall effect and thermal quantum Hall effect. A particular emphasis is put on multifractal behavior of wave functions at criticality. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Quantum Hall effect in long and in mobility adjusted GaAs/Alx Ga1–xAs samples
Authors: Diaconescu D. , Goldschmidt A. , Reuter D. , Wieck A. D. 
Published: January 2008

AbstractWe study the behaviour of the magnetoresistance in the integer quantum Hall regime in dependence on the sample length and mobility. In Hall‐bars with macroscopic lengths of up to 96 cm we find that the longitudinal specific magnetoresistance (ρxx) decreases with the distances between voltage probes. The Hall resistance in these samples shows also peculiar features – we measure very deep dips between the quantised values of the plateaus. We give a qualitative explanation for these dependencies, supposing a fully equilibrated electron transport and high back‐scattering in the sample with very long dimensions. In order to prove these assumptions, we fabricated samples with shorter dimensions but with an enhanced inter‐edge channel scattering by focused ion implantation at the sample boundaries. The Hall resistance shows similarities to those of very long samples. Implanting Ga+ ions homogeneously into Alx Ga1–x As/GaAs heterostructures offers the possibility to modify the electron mobility while keeping a constant carrier density. In this way, we vary the electron mobility of the same heterostructure within an order of magnitude whereas the electron density remains constant. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A study of the domain structure at the spin transition of the fractional quantum Hall effect
Authors: Stern O. , Dini D. , Freytag N. , Dietsche W. , von Klitzing K. , Wegscheider W. 
Published: January 2008

AbstractThe electron spin polarization at the spin transition of the fractional quantum Hall effect was measured by combining Resistance Detected (RD) NMR with conventional NMR for small and large currents. The simultaneous observation of an unshifted and a Knight‐shifted line is evidence of the different polarisation in different domain regions. Domains with full, partial or no polarization were also uncovered at v = 3/5 and 4/7. Surprisingly, measuring the conductivity with surface acoustic waves does not show any indication of the transition. This can be explained if the (conducting) domain walls have widths of less than 1% of the domains themselves. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Reinvestigation of the thermoelectric properties of Ag8GeTe6
Authors: Charoenphakdee Anek , Kurosaki Ken , Muta Hiroaki , Uno Masayoshi , Yamanaka Shinsuke 
Published: January 2008

AbstractHigh‐density polycrystalline samples (above 98% of the theoretical density) of Ag8GeTe6 were prepared by solid‐state reactions of Ag2Te, GeTe, and Te, followed by hot‐pressing. The thermoelectric properties were measured at temperatures ranging from room temperature to around 700 K. The thermal conductivity values were extremely low (0.25 Wm–1 K–1 at room temperature), and consequently Ag8GeTe6 exhibited a relatively high thermoelectric figure of merit, ZT = 0.48 at 703 K. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Scanning Probe Lithography of Polymers: Tailoring Morphology and Functionality at the Nanometer Scale
Authors: Lee Woo‐Kyung , Sheehan Paul E. 
Published: January 2008

AbstractThis article reviews the patterning of the polymer via scanning probe lithography (SPL). Several different lithographies are characterized by the source of the patterned material, whether a mechanical, electrical, or thermal field is used, and whether the lithography modifies morphology, functionality, or both. The merits of the different strategies are discussed with respect to the fabrication goals. SCANNING 30: 000–000, 2008. © 2008 Wiley Periodicals, Inc.