bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gene expression analysis of major lineage‐defining factors in human bone marrow cells: Effect of aging, gender, and age‐related disorders
Authors: Jiang Ying , Mishima Hajime , Sakai Shinsuke , Liu Yin‐kun , Ohyabu Yoshimi , Uemura Toshimasa 
Published: February 2008

AbstractAdult bone marrow cells (BMCs) include two populations:;mesenchymal stem cells (MSCs), which can differentiate into bone, cartilage, and fat; and hematopoietic stem cells (HSCs), which produce all mature blood lineage. To study the effect of aging, gender, and age‐related disorders on lineage differentiation, we performed quantitative RT‐PCR to examine mRNA expression of the major factors defining BMC lineage, cbfa1 for osteoblasts, ppar‐gamma for adipocytes, sox9 for chondrocytes, and rankl for osteoclasts, in bone marrow from 80 healthy subjects and patients (14–79 years old) with two age‐related disorders: osteoarthritis (OA) and rheumatoid arthritis (RA). Two apoptosis‐related genes, bcl‐2 and drak1, were studied. RANKL and PPAR‐Gamma levels exhibited a clear positive correlation with age in female patients, but not in males, with a slight age‐related decline in CBFa1 transcripts. DRAK1 expression showed an age‐associated ascending trend with significantly greater transcripts of RANKL and DRAK1 in females (p < 0.01). Compared with age‐matched controls, RA patients exhibited increased RANKL, PPAR‐Gamma, and DRAK1 mRNA levels (p < 0.05), and OA showed the higher RANKL and PPAR‐Gamma transcripts (p < 0.05). Furthermore, SOX9 and DRAK1 expressions in the RA group were higher than in the OA group (p < 0.05). Our data indicate that aging and age‐related disorders affect gene expressions differently, suggesting that in aging, the lineage of bone marrow cells was modified with prominent changes in decreased bone marrow osteoblastogenesis, increased adipogenesis and osteoclastogenesis, while in age‐related disorders, marrow adipogenesis and the activity or number of osteoclasts may play an important role in the pathogenesis of arthritic bone loss. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:910–917, 2008
Separation of nonionic compounds by electrokinetic chromatography using an inorganic layered compound as a pseudostationary phase
Authors: Koike Ryo , Kitagawa Fumihiko , Otsuka Koji 
Published: February 2008

AbstractThe use of an inorganic layered compound as a pseudostationary phase (PSP) in EKC was investigated. A synthetic smectite, which is the most typical swellable clay mineral, with an average diameter of 130 nm was selected as the PSP. The retention characteristics of the smectite and on‐line sample concentration by sweeping were examined for the analysis of polyoxyethylene mono phenyl ethers (PPEs) with different degrees of ethoxylation. The retention factor was increased with increase in the number of ethylene oxide groups and a good separation of the PPE homologs was achieved by smectite–EKC. The RSD of the migration time, plate number, and peak area were 0.60, 8.3, and 2.7% (n = 5), respectively. The developed method can be applied to the analysis of PPEs in commercially available consumer products without any sample pretreatments. In addition, ca. 100‐fold sensitivity enhancements for the PPEs with high retention factors were obtained by sweeping.
Micellar electrokinetic chromatography on microchips
Authors: Kitagawa Fumihiko , Otsuka Koji 
Published: February 2008

AbstractThis review highlights the methodological and instrumental developments in microchip micellar EKC (MCMEKC) from 1995. The combination of higher separation efficiencies in micellar EKC (MEKC) with high‐speed separation in microchip electrophoresis (MCE) should provide high‐throughput and high‐performance analytical systems. The chip‐based separation technique has received considerable attention due to its integration ability without any connector. This advantage allows the development of a multidimensional separation system. Several types of 2‐D separation microchips are described in the review. Since complicated channel configurations can easily be fabricated on planar substrates, various sample manipulations can be carried out prior to MCMEKC separations. For example, mixing for on‐chip reactions, on‐line sample preconcentration, on‐chip assay, etc., have been integrated on MEKC microchips. The application of on‐line sample preconcentration to MCMEKC can provide not only sensitivity enhancement but also the elucidation of the preconcentration mechanism due to the visualization ability of MCE. The characteristics of these sample manipulations on MEKC microchips are presented in this review. The scope of applications in MCMEKC covers mainly biogenic compounds such as amino acids, peptides, proteins, biogenic amines, DNA, and oestrogens. This review provides a comprehensive table listing the applications in MCMEKC in relation to detection methods.
Positivity and time behavior of a linear reaction–diffusion system, non‐local in space and time
Authors: Khrabustovskyi Andrii , Stephan Holger 
Published: February 2008

AbstractWe consider a general linear reaction–diffusion system in three dimensions and time, containing diffusion (local interaction), jumps (nonlocal interaction) and memory effects. We prove a maximum principle and positivity of the solution and investigate its asymptotic behavior. Moreover, we give an explicit expression of the limit of the solution for large times. In order to obtain these results, we use the following method: We construct a Riemannian manifold with complicated microstructure depending on a small parameter. We study the asymptotic behavior of the solution to a simple diffusion equation on this manifold as the small parameter tends to zero. It turns out that the homogenized system coincides with the original reaction–diffusion system. Using this and the facts that the diffusion equation on manifolds satisfies the maximum principle and its solution converges to a easily calculated constant, we can obtain analogous properties for the original system. Copyright © 2008 John Wiley & Sons, Ltd.
PAMAM dendrimer‐based contrast agents for MR imaging of Her‐2/neu receptors by a three‐step pretargeting approach
Authors: Zhu Wenlian , Okollie Baasil , Bhujwalla Zaver M. , Artemov Dmitri 
Published: February 2008

AbstractPretargeting of receptors is a useful approach in molecular imaging and therapy to reduce background noise or toxicity and enhance selectivity. In this study a three‐step pretargeting approach that includes a biotinylated antibody, avidin/streptavidin, and a biotinylated imaging agent is described. A PAMAM dendrimer generation 4 (G4D)‐based MRI T1 agent biotin‐G4D‐DTPA‐Gd (bG4D‐Gd) and its sister compound with remaining free surface amine groups blocked by succinic anhydride to reduce positive charges (bG4D‐Gd‐SA) were synthesized. Limited selective enhancement in MRI was observed in a Her‐2/neu mouse tumor xenograft by this three‐step pretargeting approach that includes biotinylated trastuzumab, avidin and bG4D‐Gd, or bG4D‐Gd‐SA. However, these dendrimer‐based MRI agents with molecular weight around 29 kD reached and remained in the tumor through the enhanced permeability and retention effect. Prolonged and extensive accumulation of both bG4D‐Gd and b‐G4‐Gd‐SA in the kidneys was also observed. Magn Reson Med, 2008. © 2008 Wiley‐Liss, Inc.
MT effects and T1 quantification in single‐slice spoiled gradient echo imaging
Authors: Ou Xiawei , Gochberg Daniel Frank 
Published: February 2008

AbstractWe investigated magnetization transfer (MT) effects on the steady‐state MR signal for a sample subjected to a series of identical on‐resonance RF pulses, such as would be experienced while imaging a single slice using a spoiled gradient echo sequence. The MT coupling terms for a two‐pool system were added to the Bloch equations and we derived the resulting steady‐state signal equation and compared this result to the conventional signal equation without MT effects. The steady‐state signal is increased by a few percent of the equilibrium magnetization because of MT. One consequence of this MT effect is inaccuracy in T1 values determined via conventional steady‐state gradient echo methods. (Theory predicts greater than 10% errors in T1 for white matter when using short TR.) A second consequence is the ability to quantify the relaxation and MT parameters by fitting the gradient echo steady state signal to the signal equation appropriately modified to include MT effects. The theory was tested in samples of MnCl2, cross‐linked bovine serum albumin (BSA), and cross‐linked BSA + MnCl2. Magn Reson Med, 2008. © 2008 Wiley‐Liss, Inc.
Effect of Gd‐DTPA induCED susceptibility on single‐point dixon fat/water separation
Authors: Hoory Tamar , Ramsay Elizabeth , Plewes Donald B. 
Published: February 2008

AbstractA single‐point Dixon (SPD) fat/water separation method is proposed for breast dynamic contrast‐enhanced MRI (DCE‐MRI) in which field inhomogeneities and phase offsets measured prior to the injection of gadopentate dimeglumine (Gd‐DTPA) are used to correct the postinjection images. A breast phantom study was conducted to demonstrate this technique, in which varying excess concentrations of Gd‐DTPA (0–3 mM) were introduced into a 25‐cm3 breast lesion. The presence of excess Gd‐DTPA in the lesion was found to create magnetic field perturbations of up to 0.35 μT per mM excess Gd‐DTPA around the lesion. However, these perturbations had a negligible effect on the quality of the fat/water separation for Gd‐DTPA concentrations in the range of, and exceeding, those observed in breast tumors following a standard 0.1 mmole/kg injection. Therefore, we conclude that the preinjection phase data is adequate for the correction of the postinjection images in breast exams. Magn Reson Med, 2008. © 2008 Wiley‐Liss, Inc.
A note on the mesh independence of convergence bounds for additive Schwarz preconditioned GMRES
Authors: Du Xiuhong , Szyld Daniel B. 
Published: February 2008

AbstractAdditive Schwarz preconditioners, when including a coarse grid correction, are said to be optimal for certain discretized partial differential equations, in the sense that bounds on the convergence of iterative methods are independent of the mesh sizeh. Cai and Zou (Numer. Linear Algebra Appl.2002;9:379–397) showed with a one‐dimensional example that in the absence of a coarse grid correction the usual GMRES bound has a factor of the order of$1/\sqrt {h}$. In this paper we consider the same example and show that for that example the behavior of the method is not well represented by the above‐mentioned bound: We use ana posterioribound for GMRES from (SIAM Rev. 2005;47:247–272) and show that for that example a relevant factor is bounded by a constant. Furthermore, for a sequence of meshes, the convergence curves for that one‐dimensional example, and for several two‐dimensional model problems, are very close to each other; thus, the number of preconditioned GMRES iterations needed for convergence for a prescribed tolerance remains almost constant. Copyright © 2008 John Wiley & Sons, Ltd.
Condensed‐phase flame retardation in nylon 6‐layered silicate nanocomposites: Films, fibers, and fabrics
Authors: Shanmuganathan Kadhiravan , Deodhar Sarang , Dembsey Nicholas A. , Fan Qinguo , Patra Prabir K. 
Published: February 2008

AbstractFlame‐retardant properties of nylon 6/organically modified montmorillonite (OMMT) thin films, fibers, and fabrics were investigated to determine the efficacy of condensed‐phase flame‐retardant mechanism in relation to montmorillonite concentration, sample geometry, and flame test conditions. Horizontal flame spread conducted on thin films revealed no significant difference in burning behavior between nylon 6 and nanocomposites with 5 wt% OMMT. However, with a higher concentration level of 8–10 wt% OMMT, the films burned without any dripping. The flame spread rate was reduced by 30–40% as compared with nylon 6 films. Cone calorimeter study on nanocomposite films showed that the peak heat release rate of nylon 6 was reduced by 65–67% with 8–10 wt% OMMT. Undrawn nanocomposite monofilaments with 10 wt% OMMT burned slowly and steadily in Bunsen flame without dripping. In cone calorimeter, nanocomposite fabrics with 8 wt% OMMT showed reduced heat release rate and mass loss rate compared to nylon 6 fabrics with increase in fabric tightness factor. The mass loss rate was about 40–60% less when compared with nylon 6 fabrics. The fabric char structure remained intact after burning. This demonstrated the interdependence of fabric tightness factor, OMMT concentration, and source of heat flux in forming a protective char and affecting the flammability of fabrics. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers
Yield stress and rheological characterization of the low shear zone of an epoxy molding compound for encapsulation of semiconductor devices
Authors: Yoshii Masaki 
Published: February 2008

AbstractIn encapsulation molding of IC packages, the melt flow inside the cavity is generally controlled in a low shear to prevent wire sweep, and other molding defects. Therefore, it is important to evaluate the rheological properties of epoxy molding compounds (EMC) in a low shear zone including determining the yield stress. In this study, a newly specialized Parallel‐Plate Plastometer for EMCs was built up. Using this plastometer, the yield stress and its temperature dependence were clarified, and the rheological properties in the low shear zone were evaluated. As a result, the rheological properties in a low shear zone of 0.1–10 s−1 were characterized using the Herschel–Bulkley viscosity model which introduced the yield stress, the Castro–Macosko equation as a dependency model of cure, and the WLF equation as a dependency model for temperature. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers
Proteomic analysis of S‐nitrosylated proteins in Arabidopsis thaliana undergoing hypersensitive response
Authors: Romero‐Puertas Maria C. , Campostrini Natascia , Mattè Alessandro , Righetti Pier Giorgio , Perazzolli Michele , Zolla Lello , Roepstorff Peter , Delledonne Massimo 
Published: February 2008

AbstractNitric oxide (NO) has a fundamental role in the plant hypersensitive disease resistance response (HR), and S‐nitrosylation is emerging as an important mechanism for the transduction of its bioactivity. A key step toward elucidating the mechanisms by which NO functions during the HR is the identification of the proteins that are subjected to this PTM. By using a proteomic approach involving 2‐DE and MS we characterized, for the first time, changes in S‐nitrosylated proteins in Arabidopsis thaliana undergoing HR. The 16 S‐nitrosylated proteins identified are mostly enzymes serving intermediary metabolism, signaling and antioxidant defense. The study of the effects of S‐nitrosylation on the activity of the identified proteins and its role during the execution of the disease resistance response will help to understand S‐nitrosylation function and significance in plants.
Application of proteomics technology for analyzing the interactions between host cells and intracellular infectious agents
Authors: Coiras Mayte , Camafeita Emilio , López‐Huertas María Rosa , Calvo Enrique , López Juan Antonio , Alcamí José 
Published: February 2008

AbstractHost–pathogen interactions involve protein expression changes within both the host and the pathogen. An understanding of the nature of these interactions provides insight into metabolic processes and critical regulatory events of the host cell as well as into the mechanisms of pathogenesis by infectious microorganisms. Pathogen exposure induces changes in host proteins at many functional levels including cell signaling pathways, protein degradation, cytokines and growth factor production, phagocytosis, apoptosis, and cytoskeletal rearrangement. Since proteins are responsible for the cell biological functions, pathogens have evolved to manipulate the host cell proteome to achieve optimal replication. Intracellular pathogens can also change their proteome to adapt to the host cell and escape from immune surveillance, or can incorporate cellular proteins to invade other cells. Given that the interactions of intracellular infectious agents with host cells are mainly at the protein level, proteomics is the most suitable tool for investigating these interactions. Proteomics is the systematic analysis of proteins, particularly their interactions, modifications, localization and functions, that permits the study of the association between pathogens with their host cells as well as complex interactions such as the host–vector–pathogen interplay. A review on the most relevant proteomic applications used in the study of host–pathogen interactions is presented.
Comparative LC‐MS: A landscape of peaks and valleys
Authors: America Antoine H. P. , Cordewener Jan H. G. 
Published: February 2008

AbstractQuantitative proteomics approaches using stable isotopes are well‐known and used in many labs nowadays. More recently, high resolution quantitative approaches are reported that rely on LC‐MS quantitation of peptide concentrations by comparing peak intensities between multiple runs obtained by continuous detection in MS mode. Characteristic of these comparative LC‐MS procedures is that they do not rely on the use of stable isotopes; therefore the procedure is often referred to as label‐free LC‐MS. In order to compare at comprehensive scale peak intensity data in multiple LC‐MS datasets, dedicated software is required for detection, matching and alignment of peaks. The high accuracy in quantitative determination of peptide abundancies provides an impressive level of detail. This approach also requires an experimental set‐up where quantitative aspects of protein extraction and reproducible separation conditions need to be well controlled. In this paper we will provide insight in the critical parameters that affect the quality of the results and list an overview of the most recent software packages that are available for this procedure.
Alignment of LC‐MS images, with applications to biomarker discovery and protein identification
Authors: Vandenbogaert Mathias , Li‐Thiao‐Té Sébastien , Kaltenbach Hans‐Michael , Zhang Runxuan , Aittokallio Tero , Schwikowski Benno 
Published: February 2008

AbstractLC‐MS‐based approaches have gained considerable interest for the analysis of complex peptide or protein mixtures, due to their potential for full automation and high sampling rates. Advances in resolution and accuracy of modern mass spectrometers allow new analytical LC‐MS‐based applications, such as biomarker discovery and cross‐sample protein identification. Many of these applications compare multiple LC‐MS experiments, each of which can be represented as a 2‐D image. In this article, we survey current approaches to LC‐MS image alignment. LC‐MS image alignment corrects for experimental variations in the chromatography and represents a computational key technology for the comparison of LC‐MS experiments. It is a required processing step for its two major applications: biomarker discovery and protein identification. Along with descriptions of the computational analysis approaches, we discuss their relative merits and potential pitfalls.
UV‐induced crosslinking of ring opening metathesis block copolymer micelles
Authors: Sandholzer Martina , Bichler Sabine , Stelzer Franz , Slugovc Christian 
Published: February 2008

AbstractStatistical and amphiphilic block copolymers bearing cinnamoyl groups were prepared by ring opening metathesis polymerization (ROMP). The UV‐induced [2 + 2] cycloaddition reaction of polymer bound cinnamic acid groups was studied in polymer thin films as well as in block copolymer micelles. In both cases, exposure to UV‐light for 10 min led to a crosslinking conversion of about 60%, as determined by FT‐IR spectroscopy and UV–vis absorption measurements. Time based IR‐spectroscopy revealed a maximum conversion of 78% reached after an irradiation time of about 16 min. For micelles obtained from polymers bearing 5 mol % or more cinnamoyl groups, the crosslinking reaction proceeded smoothly, yielding in crosslinked particles which were stable in a non‐selective solvent (CHCl3). Diameters determined by dynamic light scattering in the selective solvent (MeOH) were similar for both, non‐crosslinked and crosslinked micelles, whereas diameters of crosslinked micelles in the non‐selective solvent (CHCl3) were significantly larger compared to MeOH samples. This strategy of direct self assembly of block‐copolymers in a selective solvent followed by “clean” crosslinking, without the need for additional crosslinking reagents or crosslinking initiators, provides a straight forward approach toward ROMP‐based polymeric nano‐particles. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2402–2413, 2008
Quantitative IR characterization of urea groups in waterborne polyurethanes
Authors: Shi Ying , Zhan Xiaoli , Luo Zhenhuan , Zhang Qinghua , Chen Fengqiu 
Published: February 2008

AbstractThe purpose of this study is to propose a correlation between IR spectra and the urea fraction of waterborne polyurethanes (PUs) to investigate the side reaction, that is, isocyanate–water reaction, during polymerization. This method is based on the decomposition of the spectrum in amide I range, that is, 1600–1800 cm−1, where the bands of interest overlap. Several individual bands present in this region were resolved by employing Fourier self‐deconvolution (FSD) and Gaussian curve‐fitting techniques, and the intensity ratio of urethane's CO to urea's CO was determined. To realize some quantitative measurements, a calibration curve was established with some polyurethane‐urea samples, characterized by 1H NMR, which were used as standards. The concentration ratios of urethane groups to urea groups were determined from 1H NMR. A good correlation was evidenced between IR and 1H NMR measurements. Moreover, waterborne PUs were prepared by miniemulsion polymerization of IPDI with diols. From quantitative IR analysis, it was shown that a vinylic monomer, as a solvent of polyaddition, restrained the isocyanate–water reaction, and this side reaction was influenced by the hydrophilicity of the vinylic monomers. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2433–2444, 2008
Solvent‐free and nonisocyanate melt transurethane reaction for aliphatic polyurethanes and mechanistic aspects
Authors: Deepa P. , Jayakannan M. 
Published: February 2008

AbstractA novel melt transurethane polycondensation route for polyurethanes under solvent‐free and nonisocyanate condition was developed for soluble and thermally stable aliphatic or aromatic polyurethanes. The new transurethane process was investigated for A + B, A‐A + B, and A‐A + B‐B (A‐urethane and B‐hydroxyl) ‐type condensation reactions, and also monomers bearing primary and secondary urethane or hydroxyl functionalities. The transurethane process was confirmed by 1H and 13C NMR, and molecular weight of the polymers were obtained as Mn = 10–15 × 103 and Mw = 15–45 × 103 g/mol. The mechanistic aspects of the melt transurethane process and role of the catalyst were investigated using model reactions, 1H NMR, and MALDI‐TOF‐MS. The model reactions indicated the occurrence of 97% reaction in the presence of catalyst, whereas its absence gave only less than 2% of the product. The polymer samples were subjected for end‐group analysis using MALDI‐TOF‐MS, which confirms the Ti‐catalyst mediated nonisocyanate pathway in the melt transurethane process. Almost all the polyurethanes were stable up to 280 °C, and the Tg of the polyurethanes can be easily fine‐tuned from −30 to 120 °C by using appropriate diols in the melt transurethane process. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2445–2458, 2008