bluuebunny/crossref_metadata_2025_split huggingface dataset:
Single potential electrophoresis microchip with reduced bias using pressure pulse injection
Authors: Lacharme Frédéric , Gijs Martin A. M. 
Published: April 2006

AbstractWe propose two variants of a new injection technique for use in electrophoresis microchips, called “front gate pressure injection” and “back gate pressure injection”, that both enable a controlled and reproducible sample introduction with reduced bias compared to electrokinetic gated injection. A continuous flow of a test solution of fluorescein/rhodamine B in 20 mM Tris/boric acid buffer (pH 8.6) sample test solution is electrokinetically driven near to the entrance of the separation channel, using a single voltage (3 kV) that is constant in time. A sample plug is injected in the separation channel by a pressure pulse of the order of 0.1 s. The latter is generated using the mechanical deflection of a PDMS membrane that is loosely placed on a dedicated chip reservoir. The analysis of the peak area ratio of the separated compounds demonstrates a nearly constant sample composition when using pressure‐based injection. A small remaining injection bias for the shortest membrane deflection times can be attributed to a dilution effect of the charged compound due to the presence of an electrical field transverse to the sample flow boundary in the channel junction.
The effects of rock uplift and rock resistance on river morphology in a subduction zone forearc, Oregon, USA
Authors: VanLaningham Sam , Meigs Andrew , Goldfinger Chris 
Published: April 2006

AbstractRelationships between riverbed morphology, concavity, rock type and rock uplift rate are examined to independently unravel the contribution of along‐strike variations in lithology and rates of vertical deformation to the topographic relief of the Oregon coastal mountains. Lithologic control on river profile form is reflected by convexities and knickpoints in a number of longitudinal profiles and by general trends of concavity as a function of lithology. Volcanic and sedimentary rocks are the principal rock types underlying the northern Oregon Coast Ranges (between 46°30′ and 45°N) where mixed bedrock–alluvial channels dominate. Average concavity, θ, is 0·57 in this region. In the alluviated central Oregon Coast Ranges (between 45° and 44°N) values of concavity are, on average, the highest (θ = 0·82). South of 44°N, however, bedrock channels are common and θ = 0·73. Mixed bedrock–alluvial channels characterize rivers in the Klamath Mountains (from 43°N south; θ = 0·64). Rock uplift rates of ≥0·5 mm a−1, mixed bedrock–alluvial channels, and concavities of 0·53–0·70 occur within the northernmost Coast Ranges and Klamath Mountains. For rivers flowing over volcanic rocks θ = 0·53, and θ = 0·72 for reaches crossing sedimentary rocks. Whereas channel type and concavity generally co‐vary with lithology along much of the range, rivers between 44·5° and 43°N do not follow these trends. Concavities are generally greater than 0·70, alluvial channels are common, and river profiles lack knickpoints between 44·5° and 44°N, despite the fact that lithology is arguably invariant. Moreover, rock uplift rates in this region vary from low, ≤0·5 mm a−1, to subsidence (<0 mm a−1). These observations are consistent with models of transient river response to a decrease in uplift rate. Conversely, the rivers between 44° and 43°N have similar concavities and flow on the same mapped bedrock unit as the central region, but have bedrock channels and irregular longitudinal profiles, suggesting the river profiles reflect a transient response to an increase in uplift rate. If changes in rock uplift rate explain the differences in river profile form and morphology, it is unlikely that rock uplift and erosion are in steady state in the Oregon coastal mountains. Copyright © 2006 John Wiley & Sons, Ltd.
Designing a Polymer Blend with Phase Separation Tunable by Visible Light for Computer‐Assisted Irradiation Experiments
Authors: Ishino Soh , Nakanishi Hideyuki , Norisuye Tomohisa , Tran‐Cong‐Miyata Qui , Awatsuji Yasuhiro 
Published: April 2006

AbstractSummary: A mixture of poly(vinyl methyl ether) (PVME) and a polystyrene derivative bearing cinnamate groups (PSC) was chemically designed so that its phase separation can be tunable by visible light for computer‐assisted irradiation (CAI) experiments. This PSC/PVME blend exhibits a lower critical solution temperature (LCST) and undergoes phase separation upon irradiation with 405 nm visible light. The phase separation was induced by photodimerization of the cinnamate moieties in the presence of 5‐nitroacenaphthene used as a photosensitizer. It was found that for visible light with high intensity, phase separation process was almost frozen by photodimerization of the cinnamate groups which act as a photo‐cross‐linker for the PSC component. It is demonstrated in this work that by using this PSC/PVME blend, phase separation restricted to the micrometer scales can be induced and manipulated by irradiation using a computer‐controlled digital projector. These preliminary results open a new route for spatio‐temporal manipulation of phase separation in photo‐reactive polymer blends.Computer‐assisted irradiation method for a polymer blend with phase separation drivable by visible light.magnified imageComputer‐assisted irradiation method for a polymer blend with phase separation drivable by visible light.
Pentagalloylglucose inhibits estrogen receptor α by lysosome‐dependent depletion and modulates ErbB/PI3K/Akt pathway in human breast cancer MCF‐7 cells
Authors: Hua Kuo‐Tai , Way Tzong‐Der , Lin Jen‐Kun 
Published: April 2006

AbstractEstrogens and estrogen receptors (ER) play important roles in estrogen‐dependent and ER‐positive breast cancer development. Inhibitors against estrogen biosynthesis or anti‐estrogens have been used in breast cancer treatment for many years. The aim of this study was to determine whether pentagalloylglucose (5GG) has inhibitory effects on ER function. In the present study, we found that 5GG significantly reduced the growth of estrogen‐responsive human breast cancer MCF‐7 cells, and suppressed the phosphorylation and protein level of estrogen receptor α (ERα). Interestingly, 5GG decreased ERα protein levels by promoting the degradation of ERα protein in the lysosome. The ERα can be activated through a ligand‐dependent and/or a ligand‐independent pathway. The activated Akt kinase was shown to directly phosphorylate ERα at its serine residues and cause ligand independent activation. Our results showed that 5GG might inhibit the phosphatidylinositol 3‐kinase (PI3K)/Akt pathway either through directly inhibiting Akt kinase activity or through inhibiting phosphorylation of the upstream receptor tyrosine kinases. The depletion of ErbB family receptors, including epidermal growth factor receptor (EGFR), ErbB2, and ErbB3, was also observed. 5GG treatment also led to a dose‐dependent decrease in the expression of the estrogen‐activated cyclin D1 expression. These findings suggested that 5GG might be a useful chemopreventive or therapeutic agent for hormone‐dependent breast cancer through suppressing the functions of ERα by lysosome‐dependent depletion and modulating the ErbB/PI3K/Akt pathway. © 2006 Wiley‐Liss, Inc.
Variable expression of Epstein–Barr virus‐induced gene 3 during normal B‐cell differentiation and among B‐cell lymphomas
Authors: Larousserie F , Bardel E , Coulomb L'Herminé A , Canioni D , Brousse N , Kastelein RA , Devergne O 
Published: April 2006

AbstractEpstein–Barr virus (EBV)‐induced gene 3 (EBI3) is expressed by tumour cells in several EBV‐associated malignancies. EBI3 was recently found to associate with a novel peptide, p28, to form a new heterodimeric cytokine, called interleukin‐27. In this study, we investigated EBI3 and p28 expression in normal human B lymphocytes and in non‐EBV‐associated B‐cell lymphomas. Low levels of EBI3 were detected in purified tonsillar B cells and expression was upregulated upon anti‐CD40 or anti‐µ stimulation via NF‐κB activation. In non‐neoplastic tissues, EBI3 expression by lymphocytes was largely restricted to a subset of germinal centre (GC) B cells located at the margin of the light zone, in close contact with CD3+ T lymphocytes. Over 50% of EBI3+ GC B cells were engaged in cell proliferation as assessed by Ki67 expression, and 10–30% expressed MUM1, an early marker of plasma cell differentiation expressed by late centrocytes. Many EBI3+ GC B cells had downregulated bcl‐6 expression, which further suggests that these cells correspond to late CD40‐activated centrocytes. Immunohistochemical analysis of 64 B‐cell lymphomas showed that the highest EBI3 levels were detected in follicular lymphomas and in diffuse large B‐cell lymphomas of both GC B‐cell‐like or non‐GC B‐cell‐like types. No or rare p28 expression was detected in normal or tumour B cells. This constitutive expression of EBI3 by neoplastic B cells may be involved in lymphomagenesis, and may be a useful marker for lymphoma diagnosis. Copyright © 2006 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Standardisation of Gymnema sylvestre R.Br. by high‐performance thin‐layer chromatography: an improved method
Authors: Raju Valivarthi S.R. , Kannababu S. , Subbaraju Gottumukkala V. 
Published: April 2006

AbstractAn improved high‐performance thin‐layer chromatographic (HPTLC) method for the standardisation of Gymnema sylvestre is reported. The method involves the initial hydrolysis of gymnemic acids, the active ingredients, to a common aglycone followed by the quantitative estimation of gymnemagenin. The present method rectifies an error found in an HPTLC method reported recently. Copyright © 2006 John Wiley & Sons, Ltd.
HPLC analysis of leaf surface flavonoids for the preliminary classification of birch species
Authors: Lahtinen Maria , Lempa Kyösti , Salminen Juha‐Pekka , Pihlaja Kalevi 
Published: April 2006

AbstractFlavonoid aglycones found on the surfaces of birch (Betula spp.) leaves may constitute up to 10% of the dry weight of the leaf. A facile extraction and HPLC procedure has been developed that can be used for the preliminary classification of birch species according to the patterns of their leaf surface ßavonoids. The procedure involves no complex sample preparation steps, and is able to provide HPLC chromatograms from fresh leaves in less than 30 min. If necessary, leaves do not even need to be removed from the tree. Since the genus Betula is taxonomically complex and separation of different birch species can be problematic, the developed method was applied to 15 Betula species and four sub‐species of Betula pendula. Seven of the studied species were classified as B. pubescens and eight as B. pendula‐type birches. The remaining four species did not belong to either of these two classes on account of their unique pattern of external ßavonoids. The difference between the leaf surface ßavonoid composition of B. pubescens and B. pendula type birch species was unambiguously clear, and the developed method could reliably distinguish between the two species. Whilst leaf surface ßavonoids can be valuable chemotaxonomic markers, they classify birch species differently from morphological markers. Birch species with diploid chromosome sets did not contain any of the ßavanones that were present in the leaves of other species. The close relationship between the occurrence of some ßavonoid aglycones and the ploidy level of Betula species suggests that these chemotaxonomic markers may be useful both in taxonomic and phylogenetic analyses. Copyright © 2006 John Wiley & Sons, Ltd.
A high‐performance liquid chromatography with electrochemical detection for the determination of total hypericin in extracts of St. John's wort
Authors: Rückert Ulla , Eggenreich Karin , Likussar Werner , Wintersteiger Reinhold , Michelitsch Astrid 
Published: April 2006

AbstractAn HPLC method for the quantitation of hypericin using a new and sensitive amperometric detection is presented. Hypericin was eluted isocratically using a mobile phase consisting of ammonium acetate, methanol and acetonitrile. The oxidation was carried out with a glassy carbon electrode at a potential of +1.1 V vs. an Ag–AgCl–KCl reference electrode. Under the conditions described, hypericin was separated at a retention time (Rt) of 12 min. Linearity was obtained over the range 0.035–1.30 µg/mL (r = 0.9994). The limit of detection was determined to be 0.010 ng on‐column for hypericin. The method was applied to the determination of total hypericin (hypericin, pseudohypericin, protohypericin and protopseudohypericin) in extracts of St. John's wort using hypericin as an external standard. The protoforms were converted into hypericin and pseudohypericin by subjecting the sample to artificial light prior to chromatographic analysis. For the evaluation of total hypericin, the peak areas of pseudohypericin (Rt 3.7 min) and hypericin (Rt 12.0 min) were combined. The relative standard deviation in analysing samples containing Hypericum ranged from 2.5 to 5.4%. Copyright © 2006 John Wiley & Sons, Ltd.
Chemically modified proton‐conducting membranes based on sulfonated polyimides: Improved water stability and fuel‐cell performance
Authors: Yin Yan , Yamada Otoo , Hayashi Shunsuke , Tanaka Kazuhiro , Kita Hidetoshi , Okamoto Ken‐Ichi 
Published: April 2006

AbstractA series of branched/crosslinked sulfonated polyimide (B/C‐SPI) membranes were prepared and evaluated as proton‐conducting ionomers based on the new concept of in situ crosslinking from sulfonated polyimide (SPI) oligomers and triamine monomers. Chemical branching and crosslinking in SPI oligomers with 1,3,5‐tris(4‐aminophenoxy)benzene as a crosslinker gave the polymer membranes very good water stability and mechanical properties under an accelerated aging treatment in water at 130 °C, despite their high ion‐exchange capacity (2.2–2.6 mequiv g−1). The resulting polymer electrolytes displayed high proton conductivities of 0.2–0.3 S cm−1 at 120 °C in water and reasonably high conductivities of 0.02–0.03 S cm−1 at 50% relative humidity. In a single H2/O2 fuel‐cell system at 90 °C, they exhibited high fuel‐cell performances comparable to those of Nafion 112. The B/C‐SPI membranes also displayed good performances in a direct methanol fuel cell with methanol concentrations as high as 50 wt % that were superior to those of Nafion 112. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3751–3762, 2006
Electrostatic Charge Measurement and Charge Neutralization of Fine Aerosol Particles during the Generation Process
Authors: Tsai Chuen‐Jinn , Lin Jyh‐Shyan , Deshpande C. G. , Liu Li‐Chun 
Published: April 2006

AbstractAn aerosol charge analyzer has been constructed to measure the charge distribution of NaCl particles generated in the laboratory. A radioactive electrostatic charge neutralizer utilizing Po‐210 was used to neutralize the electrostatic charge of the particles. The atomization technique was used to generate NaCl particles with diameters of 0.2 to 0.8 μm, while the evaporation and condensation method was adopted to generate particles of 0.01 to 0.2 μm in diameter. The experimental data demonstrates that the absolute average particle charge depends on the particle diameter, and is higher than that calculated by the Boltzmann charge equilibrium for particles within the range of 0.2 to 0.8 μm. The charge increases with decreasing NaCl concentration. When these particles are neutralized using the Po‐210 neutralizer, it is found that the electrostatic charge reaches the Boltzmann charge equilibrium. For 0.01 to 0.2 μm NaCl particles generated using the evaporation and condensation method, test results show that the absolute average particle charge is higher than that calculated by the Boltzmann charge equilibrium for particles larger than 0.03 to 0.05 μm in diameter, while it is lower than that predicted by the Fuchs theory [1], for particles smaller than 0.03 to 0.05 μm. However, after charge neutralization, particles with diameter above 0.05 μm reach the Boltzmann charge equilibrium condition, and the charges for particles with diameters of 0.010 to 0.05 μm, agree well with Fuchs' theory.
Determination of Particle Size Distribution by Laser Diffraction of Doped‐CeO2 Powder Suspensions: Effect of Suspension Stability and Sonication
Authors: Desroches Marie J. , Castillo Ian A. , Munz Richard J. 
Published: April 2006

AbstractThe particle size distributions (PSDs) of metal oxide powders are often determined by analyzing suspensions of powders using laser diffraction (e.g. Malvern MasterSizer 2000). Particle agglomeration can effectively bias the resulting distribution towards “unrealistic” particle sizes. Solutions to avoid this problem must be found if a particle distribution based on the elemental or primary particle sizes is desired.In this work, the particle size distribution of doped‐CeO2 powders was studied. These powders show a crystalline single phase structure of controlled stoichiometry as determined by X‐ray diffraction and ICP analysis. The apparent size distribution was found to be a strong function of suspension stability. Dispersant agents (PBTCA and phosphonoacetic acid) and suspension pH affected stability as characterized by zeta potential measurements. Sonication of the suspensions further enhanced particle de‐agglomeration. Finally, only the combined effect of a dispersant agent, pH adjustment of the suspension and sonication provided a primary particle size distribution. The results presented in this work can be used in the analysis of similar ceramic powders in which strong particle agglomeration is present.
The Stability and Functionality of Chemically Crosslinked Microtubules
Authors: Boal Andrew K. , Tellez Hernesto , Rivera Susan B. , Miller Nicholas E. , Bachand George D. , Bunker Bruce C. 
Published: April 2006

AbstractA variety of bifunctional crosslinking agents have been explored for stabilizing microtubule shuttles used for the active transport of nanomaterials in artificial environments. Crosslinking agents that target amine residues form intertubulin crosslinks that produce crosslinked microtubules (CLMTs) with structural and functional lifetimes that can be up to four times as long as those achieved with taxol stabilization. Such CLMTs are stable at temperatures down to −10 °C, are resistant to depolymerization induced by metal ions such as Ca2+, and yet continue to be adsorbed and transported by self‐assembled monolayers containing the motor protein kinesin. However, crosslinkers that target cysteine residues depolymerize the MTs, probably by interfering with the guanosine triphosphate binding site. The impact of crosslink attributes, including terminal group chemistry, chain length, crosslink density, and specific location on the tubulin surface, on microtubule stability and functionality are discussed.
Methotrexate‐Immobilized Poly(ethylene glycol) Magnetic Nanoparticles for MR Imaging and Drug Delivery
Authors: Kohler Nathan , Sun Conroy , Fichtenholtz Alex , Gunn Jonathan , Fang Chen , Zhang Miqin 
Published: April 2006

AbstractWe report the development of a biostable methotrexate‐immobilized iron oxide nanoparticle drug carrier that may potentially be used for real‐time monitoring of drug delivery through magnetic resonance imaging. Methotrexate (MTX) was immobilized on the nanoparticle surface via a poly(ethylene glycol) self‐assembled monolayer (PEG SAM). The cytotoxicity of the nanoparticle–drug conjugate (NP‐PEG‐MTX) to target cells was studied with 9L glioma cells. Cellular uptake experiments showed that the uptake of NP‐PEG‐MTX conjugates by glioma cells was considerably higher than that of control nanoparticles. Magnetic resonance imaging in 9L cells cultured with NP‐PEG‐MTX of various concentrations showed significant contrast enhancement. NP‐PEG‐MTX demonstrated higher cytotoxicity in 9L cells to free MTX in vitro. Leucovorin, an MTX antidote, was used to rescue the cells that had been exposed to NP‐PEG‐MTX or free MTX, and the experiment verified the biocompatibility of NP‐PEG‐MTX conjugates and the MTX on NP‐PEG‐MTX conjugates to be the true source of the cytotoxicity to the target cells. TEM results showed that NP‐PEG‐MTX conjugates were internalized into the 9L cellular cytoplasm and retained its crystal structure therein for up to 144 h, as identified by electron diffraction. This prolonged particle retention may allow physicians to image tumor cells exposed to the NP‐PEG‐MTX conjugate over an extended therapeutic time course.
Papillary Microcarcinoma: Is There Any Difference between Clinically Overt and Occult Tumors?
Authors: Lo Chung‐Yau , Chan Wai‐Fan , Lang Brian Hung‐Hin , Lam King‐Yin , Wan Koon‐Yat 
Published: April 2006

AbstractIntroductionPapillary microcarcinoma (PMC) is a subtype of papillary thyroid carcinoma (PTC) associated with excellent prognosis. However, clinical and biologic behaviors of PMC may vary considerably between tumors that are clinically overt and those that are occult.Materials and MethodsFrom 1964 to 2003, 185 of 628 patients with PTC were identified as having PMC, based on tumor size ≤1 cm. There were 110 overt and 75 occult PMCs detected based on clinical presentation. The clinicopathologic features, treatment, and long‐term outcome of PMCs were evaluated and compared between the two groups.ResultsThere were 37 men and 148 women with a median age of 45 years (range: 11–84 years). The median tumor size was 6.2 mm. Thirty‐eight (21%) patients presented with cervical nodal metastases. Three (1.6%) had distant metastases and 5 (2.7%) underwent incomplete resection. Bilateral procedures were performed for 129 patients (70%) and 53 (29%) received postoperative I131treatment. During a mean follow‐up of 8.2 years, 4 patients died of the disease and 13 developed recurrence. Clinically overt PMCs were significantly larger, were more likely to be multifocal, and more likely to lead to bilateral thyroidectomy. Extrathyroidal or lymphovascular invasion, nodal metastases, I131ablation, high‐risk tumors, and postoperative recurrence occurred in overt PMC only. Patients with nodal metastases had a decreased survival and an increase in locoregional recurrence.ConclusionsDespite a relatively good prognosis in PMC, a distinction should be made between clinically overt and occult PMCs in which clinically overt PMC should be managed according to tumor risk profile and clinical presentation.