bluuebunny/crossref_metadata_2025_split huggingface dataset:
Expression and DNA‐binding activity of MYCN/Max and Mnt/Max during induced differentiation of human neuroblastoma cells
Authors: Smith Anna Grynfeld , Popov Nikita , Imreh Martha , Axelson Håkan , Henriksson Marie 
Published: June 2004

AbstractAmplification ofMYCNis one of the most important prognostic markers for neuroblastoma and is correlated with rapid tumor progression and poor prognosis. MYCN belongs to the Myc/Max/Mad/Mnt network of proteins that regulate proliferation, apoptosis, and differentiation. It is well established thatMYCNis downregulated during induced differentiation of neuroblastoma cells carrying an amplifiedMYCNgene, but very little is known about other components of the network, i.e., the Max, Mad, and Mnt proteins, during this process. In this study we show thatMad and Mnt expressionwas only modestly regulated in differentiating SK‐N‐BE(2) neuroblastoma cells, whileMYCNwas rapidly downregulated. This downregulation was reflected in a decreased MYCN/Max DNA‐binding activity while the Mnt/Max binding did not change during differentiation. In parallel experiments we also analyzed the Myc/Max/Mad expression and DNA binding capacity during induced differentiation in theMYCNsingle copy neuroblastoma cell line SH‐SY5Y. In this cell line only modest changes in expression of the components of the MYCN/Max/Mad/Mnt network was detected, but since the cell line expresses relatively low levels of MYCN and c‐Myc, these changes might be of functional significance. Cell cycle analyses of SK‐N‐BE(2) demonstrated an increase in the G1‐phase fraction after RA‐treatment. These data show that the decreasedMYCNexpression and MYCN DNA‐binding is correlated with retarded cell cycle progression. Furthermore, whenMad1 or Mntwas overexpressed in SK‐N‐BE(2) cells they retained the capacity to differentiate, underscoring the notion that MYCN downregulation, and not changes inMad/Mntexpression, is essential for neuroblastoma cell differentiation. © 2004 Wiley‐Liss, Inc.
Soluble form of Jagged1: Unique product of epithelial keratinocytes and a regulator of keratinocyte differentiation
Authors: Aho Sirpa 
Published: June 2004

AbstractNotch signaling pathway is an important regulator of epithelial differentiation. Recent studies have characterized multiple ligands, including Jagged1, as mediators of Notch signaling. In this work, an alternatively spliced transcript of Jagged1 was isolated in yeast two‐hybrid screening through interaction with thrombospondin‐1. This transcript, devoid of sequences encoding the transmembrane and intracellular domains of Jagged1, was specific for keratinocytes. Furthermore, the truncated Jagged1 polypeptide devoid of the intracellular domain was detected prominently in the suprabasal keratinocyte layer in neonatal epithelia. The soluble form of Jagged1, when expressed as a tagged polypeptide was efficiently secreted into the culture medium and the N‐terminal signal sequence became cleaved off upon secretion. Direct contact between a cell presenting the transmembrane form of Jagged1 and a Notch‐expressing cell has been proposed as a prerequisite for the signaling event. However, the soluble form of Jagged1, when present in the cell culture medium, was sufficient to induce keratinocyte differentiation. These observations suggest a novel mechanism of how Jagged1 can target cells beyond the direct cell–cell contact in developing epithelia. © 2004 Wiley‐Liss, Inc.
Structural analysis of 2,6‐[bis(alkyloxy)methyl]‐phenyltin derivatives using electrospray ionization mass spectrometry
Authors: Kolářová Lenka , Holčapek Michal , Jambor Roman , Dostál Libor , Nádvorník Milan , Růžička Aleš 
Published: June 2004

AbstractElectrospray ionization (ESI) mass spectrometry was applied to the structural analysis of 23 2,6‐[bis(alkyloxy)methyl]phenyltin(IV) derivatives. The mass spectra were measured in both polarity modes and multistage tandem mass spectrometric (MSn) measurements were performed on the ion trap analyser for positively charged tin‐containing ions. The sum of complementary ions observed in the positive‐ion mode (i.e. [M–R3]+ ion) and in the negative‐ion mode (i.e. [R3]− ion) permits molecular mass determination in spite of the fact that the molecular adducts were often missing even in the first‐order mass spectra. The subsequent fragmentation of [M–R3]+ ions studied by MSn and the correlation of observed fragment ions with the expected structures of synthesized organotin(IV) compounds allowed us to understand the fragmentation behaviour and the mechanism of the ion formation for studied compounds. The typical neutral losses are alkenes, alcohols and aldehydes. The fragmentation pattern of one selected compound was supported by MSn measurements of an isotopically labelled analogue to confirm unusual ion–molecule reactions of some fragment ions with water in the ion trap. Copyright © 2004 John Wiley & Sons, Ltd.
Interactions of Enzymes and a Lectin with a Chitin‐Based Graft Copolymer Having Polysarcosine Side Chains
Authors: Nakamura Rikiya , Aoi Keigo , Okada Masahiko 
Published: June 2004

AbstractSummary: The molecular‐recognition abilities of a water‐soluble chitin derivative, chitin‐graft‐polysarcosine (2) were investigated using chitinase, lysozyme, and wheat germ agglutinin (WGA). The enzymatic degradabilities of 2 were evaluated using chitinase and lysozyme. The molecular weight of those compounds of 2 with a higher affinity toward water decreased rapidly, as compared with partially deacetylated chitin (1). The 1H NMR spectrum of the low‐molecular‐weight fraction, yielded after lysozymic hydrolysis, indicated that saccharide residues in the chitinous backbone were specifically recognized by the lysozyme, then β‐glycosidic linkages in the backbone were selectively hydrolyzed. Furthermore, the molecular‐recognition ability of the chitinous backbone of graft copolymer 2 toward the lectin WGA was elucidated by the enzyme‐linked lectin‐binding assay (ELLA). It was revealed that the graft copolymer with a lower degree of substitution (DS) value efficiently interacted with WGA. Interestingly, a graft copolymer having longer polysarcosine side chains showed higher recognition ability toward WGA than that having short side chains.The structure of the graft copolymer, chitin‐graft‐polysarcosine 2, used here.magnified imageThe structure of the graft copolymer, chitin‐graft‐polysarcosine 2, used here.
Formation of in situ CB/PET Microfibers in CB/PET/PE Composites by Slit Die Extrusion and Hot Stretching
Authors: Xu Xiang‐Bin , Li Zhong‐Ming , Yu Run‐Ze , Lu Ai , Yang Ming‐Bo , Huang Rui 
Published: June 2004

AbstractSummary: In this present study, the in situ fabrication of a microfibrillar composite based on poly(ethylene terephthalate) (PET), polyethylene (PE), and carbon black (CB) is attempted. PET and CB were first melt mixed. The CB/PET compound and PE were subsequently melt extruded through a slit die and then hot stretched. The morphological observation of the as‐stretched extrudate indicated that well‐defined microfibers of CB/PET compound could be generated at appropriate CB contents and a fixed hot stretch ratio. In addition, CB was always selectively located in PET. The microfibrillar CB/PET/PE composite has the potential to be a new electrically conductive polymer composite.Morphology of the carbon black/poly(ethylene terephthalate)/polyethylene (PE) composite after additional mixing in the mixer at the processing temperature of PE.magnified imageMorphology of the carbon black/poly(ethylene terephthalate)/polyethylene (PE) composite after additional mixing in the mixer at the processing temperature of PE.
Lp Decay problem for the dissipative wave equation in even dimensions
Authors: Ono Kosuke 
Published: June 2004

AbstractWe study Lp decay estimates of the solution to the Cauchy problem for the dissipative wave equation in even dimensions: (□+∂t)u=0 in ℝN × (0,∞) for even N=2n⩾2 with initial data (u,∂tu)∣t=0 =(u0,u1). The representation formulas of the solution u(t)=∂tS(t)u0 + S(t)(u0+u1) provide the sharp estimates on Lp norms with p⩾1. Copyright © 2004 John Wiley & Sons, Ltd.
Some non‐standard problems in viscous flow
Authors: Payne L. E. , Schaefer P. W. , Song J. C. 
Published: June 2004

AbstractEnergy bounds are derived for Dirichlet type boundary value problems for the Navier–Stokes and Stokes equations when a combination of the solution values initially and at a later time is prescribed. The bounds are obtained by means of a differential inequality and imply uniqueness and continuous data dependence of the solutions for a range of values of the parameter in the non‐standard auxiliary condition. Copyright © 2004 John Wiley & Sons, Ltd.
Electromagnetic periodic structure bandpass filter (EPS‐BPF) with two transmission zeros
Authors: Her Man‐Long , Chiou Yi‐Chyun , Wang Yu‐Zhen , Lin Kun‐Ying 
Published: June 2004

AbstractIn this paper, an improved electromagnetic periodic structure bandpass filter (EPS‐BPF) is designed and analyzed, and its equivalent circuit is also presented. The proposed structure achieves two transmission zeros on both sides of passband, while a good rolling skirt is obtained as well. The measured results show that the filter has a fractional 3‐dB bandwidth of 16%, and its insertion and return losses are −2 and −27 dB at the 5‐GHz center frequency, respectively. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 42: 265–267, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20273
Modulation bandwidth of semiconductor lasers based on coupled quantum wells
Authors: Wartak M. S. , Weetman P. 
Published: June 2004

AbstractThe effect of well coupling on differential gain and maximum‐modulation bandwidth for semiconductor lasers based on coupled quantum wells is analyzed using the K‐factor method. We determine differential gain in coupled quantum wells within the self‐consistent solution of the Poisson, Schroedinger, and 4 × 4 Luttinger–Kohn equations. The multiple‐body effects of bandgap renormalization, coulombic scattering interactions, and a nonMarkovian distribution are also included. The analysis has been performed for coupled wells at 1.55 μm in an InGaAsP/InP lattice‐matched system grown in the [001] direction. Our results suggest that in order to maximize modulation bandwidth and differential gain, one should design structures with barrier widths larger than 40 Å. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 42: 272–274, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20275
Design of an X‐band tray‐type spatial power combiner using uniplanar quasi‐Yagi antennas
Authors: Tsai Feng‐Chi E. , Bialkowski Marek E. 
Published: June 2004

AbstractThe design of an X‐band tray‐type spatial power combiner, which employs uniplanar quasi‐Yagi antennas (QYAs) for receiving and transmitting signals by individual amplifiers, is presented. Passive and active varieties of a seven‐tray power‐combining structure that includes two hard horns for uniform signal launching and combining across the tray stack are developed and measured. In order to compensate for nonuniform phase across the stack, which is caused by the nonplanar wave front of the horn antennas, Schiffman phase shifters are implemented in individual trays. The experimental results show an improved performance of the investigated tray‐type power combiner when the proposed phase‐error compensation is implemented. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 42: 307–311, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20287
New compact microstrip‐patch bandpass filter with two transmission zeros
Authors: Wang Xuedong , Zou Jie , Li Ying 
Published: June 2004

AbstractThis paper presents a new compact and simple microstrip‐patch bandpass filter structure using only one resonator. This filter has two transmission zeros on the both sides of the passband. The volume of this filter is about 1/3 or 1/2 of a conventional filter. Because the new filter is without coupling gaps, uncertainty during fabrication can be reduced. The effects of varying the parameters of the structure have been studied. The simulated results agree well with the measured results. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 42: 315–317, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20289
Design and analyses of compact bent‐tapered waveguides using guided‐wave lens sets
Authors: Chang Chun‐Wen , Hsieh Wen‐Feng 
Published: June 2004

AbstractWe propose compact bent‐tapered waveguides using guided‐wave lens sets, which are constructed by disposing lens‐shaped waveguide regions in planar tapered waveguides. Two applications of the abruptly bent tapered waveguide and the Z‐bend tapered waveguide demonstrate high transmittances of 91% and 86% with bent and tapered angles of 10°. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 42: 324–328, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20292
Coplanar waveguide (CPW) defected ground structure (DGS) for bandpass filter application
Authors: Her Man‐Long , Wang Yu‐Zhen , Chang Chih‐Min , Lin Kun‐Ying 
Published: June 2004

AbstractIn this paper, we design and implement a coplanar waveguide (CPW) bandpass filter utilizing defected ground structure (DGS) technology. The CPW DGS technology, which only needs one or a series connection of a few cells to exhibit the bandgap characteristics, can provide the attenuation poles in the upper and lower bands to improve the rolloff characteristics of the bandpass filter. Moreover, the equivalent lump values of the CPW DGS are also calculated and good agreement between EM simulation and numerical calculation is obtained. The measured results show that the improved selectivity of upper and lower bands are 10.7 and 46.5 dB/GHz, respectively. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 42: 331–334, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20294
Prediction of the reflection coefficient of shallow buried objects by a microwave technique
Authors: Furlan‐Achrait L. , Lasri T. , Mamouni A. 
Published: June 2004

AbstractIn this paper, we propose a low‐cost microwave technique to characterize shallow subsurface objects. Experiments and simulations are carried out to explore the possibility of predicting the reflection coefficient, according to one or two dimensions, of buried structures. High and low contrasts between the host medium and the object are investigated. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 42: 335–339, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20295
Synthesis of alkaline‐developable, photosensitive hyperbranched polyimides through the reaction of carboxylic acid dianhydrides and trisamines
Authors: Makita Shohei , Kudo Hiroto , Nishikubo Tadatomi 
Published: June 2004

AbstractHyperbranched polyimides (HBPI)s with high glass‐transition temperatures and excellent thermal stability were synthesized through the reaction of commercially available carboxylic acid dianhydrides with tris[4‐(4‐aminophenoxy)phenyl]ethane (TAPE). In particular, hyperbranched polyimide HBPI(TAPE‐DSDA), prepared through the reaction of TAPE with 3,3′,4,4′‐diphenylsulfonetetracarboxylic dianhydride (DSDA), showed higher thermal stability and good solubility. Furthermore, alkaline‐developable, photosensitive HBPI(TAPE‐DSDA)‐MA‐CA was prepared through the reaction of HBPI(TAPE‐DSDA) with glycidyl methacrylate with tetrabutylammonium bromide as a catalyst in N‐methyl‐2‐pyrrolidinone (NMP) followed by the addition reaction of cis‐1,2,3,6‐tetrahydrophthalic anhydride with triphenylphosphine as a catalyst in NMP. The glass‐transition temperatures of HBPI(TAPE‐DSDA)‐MA‐CA were greater than 300 °C. A resist composed of 74 wt % HBPI(TAPE‐DSDA)‐MA‐CA, 22.2 wt % trimethylpropane triacrylate, and 3.8 wt % Irgacure 907 as a photoinitiator achieved a resolution of a 55‐μm line pattern and a 275‐μm space pattern by UV irradiation (1000 mJ/cm2). © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3697–3707, 2004
On the Mechanism of Low Temperature Oxidation for Aluminum Particles down to the Nano‐Scale
Authors: Eisenreich Norbert , Fietzek Harald , del Mar Juez‐Lorenzo Maria , Kolarik Vladislav , Koleczko Andreas , Weiser Volker 
Published: June 2004

AbstractThe oxidation of Al‐particles down to nano‐scale was investigated by TG, SEM and in‐situ X‐ray diffraction. Al particles are usually coated by a 2–4 nm layer of Al2O3 which can be derived from the degree of weight increase on complete oxidation by TG‐curves. The low temperature oxidation of Al particles occurs at least in two steps. The first step builds a layer of 6 to 10 nm thickness composed of crystallites of the same size independent on the initial particle size. This reaction is dominated by chemical kinetics and converts a substantial fraction of the particle if the particle sizes decrease below 1 μm, an effect carefully to be taken into account for nano‐particles because of safety reasons. The second step combines diffusion and chemical reaction and proceeds therefore slowly, the slower the bigger the particles are. The kinetic parameters of these two steps can be obtained by a model taking into account both reaction steps, chemical kinetics and diffusion for spherical particles when fitting it to TG‐curves. X‐ray diffraction shows that particles smaller than 1 μm build γ‐ and θ‐Al2O3 in the first step with nano‐crystalline structures which are then transformed to α‐Al2O3.
X‐ray structure of a membrane‐bound β‐glycosidase from the hyperthermophilic archaeon Pyrococcus horikoshii
Authors: Akiba Toshihiko , Nishio Miho , Matsui Ikuo , Harata Kazuaki 
Published: June 2004

AbstractThe β‐glycosidase of the hyperthermophilic Archaeon Pyrococcus horikoshii is a membrane‐bound enzyme with the preferred substrate of alkyl‐β‐glycosides. In this study, the unusual structural features that confer the extreme thermostability and substrate preferences of this enzyme were investigated by X‐ray crystallography and docking simulation. The enzyme was crystallized in the presence of a neutral surfactant, and the crystal structure was solved by the molecular replacement method and refined at 2.5 Å. The main‐chain fold of the enzyme belongs to the (βα)8 barrel structure common to the Family 1 glycosyl hydrolases. The active site is located at the center of the C‐termini of the barrel β‐strands. The deep pocket of the active site accepts one sugar unit, and a hydrophobic channel extending radially from there binds the nonsugar moiety of the substrate. The docking simulation for oligosaccharides and alkylglucosides indicated that alkylglucosides with a long aliphatic chain are easily accommodated in the hydrophobic channel. This sparingly soluble enzyme has a cluster of hydrophobic residues on its surface, situated at the distal end of the active site channel and surrounded by a large patch of positively charged residues. We propose that this hydrophobic region can be inserted into the membrane while the surrounding positively charged residues make favorable contacts with phosphate groups on the inner surface of the membrane. The enzyme could thus adhere to the membrane in the proximity of its glycolipid substrate. Proteins 2004. © 2004 Wiley‐Liss, Inc.
Rational proteomics II: Electrostatic nature of cofactor preference in the short‐chain oxidoreductase (SCOR) enzyme family
Authors: Pletnev Vladimir Z. , Weeks Charles M. , Duax William L. 
Published: June 2004

AbstractThe dominant role of long‐range electrostatic interatomic interactions in nicotinamide adenine dinucleotide/nicotinamide adenine dinucleotide phosphate (NAD/NADP) cofactor recognition has been shown for enzymes of the short‐chain oxidoreductase (SCOR) family. An estimation of cofactor preference based only on the contribution of the electrostatic energy term to the total energy of enzyme–cofactor interaction has been tested for ∼40 known three‐dimensional (3D) crystal complexes and ∼330 SCOR enzymes, with cofactor preference predicted by the presence of Asp or Arg recognition residues at specific 3D positions in the β2α3 loop (Duax et al., Proteins 2003;53:931–943). The results obtained were found to be consistent with ∼90% reliable cofactor assignments for those subsets. The procedure was then applied to ∼170 SCOR enzymes with completely uncertain NAD/NADP dependence, due to the lack of Asp and Arg marker residues. The proposed 3D electrostatic approach for cofactor assignment (“3D_ΔEel”) has been implemented in an automatic screening procedure, and together with the use of marker residues proposed earlier (Duax et al., Proteins 2003;53:931–943), increases the level of reliable predictions for the putative SCORs from ∼70% to ∼90%. It is expected to be applicable for any NAD/NADP‐dependent enzyme subset having at least 25–30% sequence identity, with at least one enzyme of known 3D crystal structure. Proteins 2004. © 2004 Wiley‐Liss, Inc.
Natural attenuation of chlorinated solvent plumes at Texas dry cleaners
Authors: Suarez Monica P. , Rifai Hanadi S. , Rittaler Tricia J. , Hausman Sarah 
Published: June 2004

AbstractDry cleaners are the largest users of perchloroethene (PCE) solvents in the United States. Releases from dry cleaners to soil and groundwater, however, remain largely unstudied. This article presents a database of 137 chlorinated solvent plumes at dry cleaners in Texas. The data indicate that PCE plumes are generally shorter in extent than those from industrial sites. Degradation products were observed at more than 80 percent of the sites with groundwater contamination. Calculated attenuation rates are on the order of one‐to‐three‐year half‐lives for PCE and its degradation products. The estimated cleanup timeframe for calculated attenuation rates is < 50 years. More research is needed to understand the presence of organic carbon sources at dry cleaners and its implications for natural attenuation. © 2004 Wiley Periodicals, Inc.