bluuebunny/crossref_metadata_2025_split huggingface dataset:
The role of constitutively active signal transducer and activator of transcription 3 in ovarian tumorigenesis and prognosis
Authors: Rosen Daniel G. , Mercado‐Uribe Imelda , Yang Gong , Bast Robert C. , Amin Hesham M. , Lai Raymond , Liu Jinsong 
Published: October 2006

AbstractBACKGROUND.Signal transducer and activator of transcription 3 (Stat3), which is a latent transcription factor that participates in the transcriptional activation of apoptosis and cell cycle progression, has been implicated as an oncogene in several neoplastic diseases. However, the specific role of Stat3 in ovarian carcinogenesis remains poorly understood. The objectives of the current study were to examine the effect of Stat3 activation on the phenotypic transformation of an immortalized, nontumorigenic ovarian epithelial cell line and to evaluate the expression of tyrosine‐activated Stat3 (pStat3) in tissue microarrays from 303 ovarian carcinomas to determine its prognostic relevance and to correlate its expression with several upstream oncogenes of Stat3 and with the oncogenes involved in apoptosis and proliferation.METHODS.Overexpression of pStat3 was weakly tumorigenic and produced measurable tumors in mice in 1 of 3 clones. Using tissue microarrays from a large group of patients with primary ovarian carcinoma, the expression of pStat3 was correlated with the expression of growth factor receptors (HER‐2/neu and epidermal growth factor receptor [EGFR]), interleukin 6, and the proliferation and apoptosis markers Ki‐67, Bcl‐2, and Bcl‐xL and with clinicopathologic variables and patient survival.RESULTS.High pStat3 expression in the tumor tissue microarray was associated with high levels of HER‐2/neu, EGFR, and Ki‐67. No correlation was observed between overall pStat3 levels and any other clinicopathologic variables tested. High nuclear expression of pStat3 (>10% of positive‐stained cells) was linked with poor overall survival.CONCLUSIONS.The activation and translocation of pStat3 to the nucleus are frequent events in ovarian carcinoma that are associated with a poor prognosis. Further studies are needed to elucidate the mechanism of activation of Stat3, its effects on downstream targets, and its role in the neoplastic transformation of epithelial ovarian cells. Cancer 2006. © 2006 American Cancer Society.
True monolayer cell culture in a confined 3D microenvironment enables lineage informatics
Authors: Ramunas John , Illman Meredith , Kam Angela , Farn Kristen , Kelly Liam , Morshead Cindi M. , Jervis Eric J. 
Published: October 2006

AbstractBackground:There is a need for methods to (1) track cells continuously to generate lineage trees; (2) culture cells in in vivo‐like microenvironments; and (3) measure many biological parameters simultaneously and noninvasively. Herein, we present a novel imaging culture chamber that facilitates “lineage informatics,” a lineage‐centric approach to cytomics.Methods:We cultured cells in a confined monolayer using a novel “gap chamber” that produces images with confocal‐like qualities using standard DIC microscopy. Lineage and other cytometric data were semiautomatically extracted from image sets of neural stem and progenitor cells and analyzed using lineage informatics.Results:Cells imaged in the chamber every 3 min could be tracked for at least 6 generations allowing for the construction of extensive lineage trees with multiparameter data sets at hundreds of time points for each cell. The lineage informatics approach reveals relationships between lineage, phenotype, and microenvironment. Mass transfer characteristics and 3D geometry make the chamber more in vivo‐like than traditional culture systems.Conclusions:The gap chamber allows cells to be cultured, imaged, and tracked in true monolayers permitting detailed informatics analysis of cell lineage, phenotype, and fate determinants. The chamber is biomimetic and straightforward to build and use, and should find many applications in long‐term cell imaging. © 2006 International Society for Analytical Cytology
Interactions of hydrophobic and hydrophilic solvent component degradation in an air‐phase biotrickling filter reactor
Authors: Paca Jan , Klapkova Eva , Halecky Martin , Jones Kim , Webster Todd S. 
Published: October 2006

AbstractInteractions amongst the degradation rates of toluene, xylenes, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), and n‐butyl acetate (n‐BA) were investigated. Experiments were performed in a biotrickling filter reactor packed with polypropylene Pall rings in a counter‐current air–water mode of operation. Under pseudo‐steady‐state conditions, the removal efficiency (RE) of the individual components in the middle of and at the effluent above the reactor bed was evaluated. By using a mixed microbial culture as the biocatalyst, the results revealed that an increased loading of toluene and xylene had a competitive effect on the RE of MIBK. After reaching a saturation point of the overall catabolic capacity of the biocatalyst, variations of RE were observed for the different components. This was most pronounced under conditions of overloading with the water‐soluble components mixture. Despite such variations, the system was able to efficiently degrade this complex pollutant mixture for a period of 1 yr. © 2006 American Institute of Chemical Engineers Environ Prog, 2006
Two novel applications of ion exchange fibers: Arsenic removal and chemical‐free softening of hard water
Authors: Greenleaf John E. , Lin Jin‐cheng , Sengupta Arup K. 
Published: October 2006

AbstractSeparation processes using ion exchange materials are ubiquitous regarding the selective removal of contaminants of environmental concern. Recently, highly regulated contaminants, such as arsenic, have gained notoriety on account of carcinogenic effects and subsequent promulgation of new drinking water standards by the United States Environmental Protection Agency. Other nonregulated compounds such as hardness (e.g., Ca2+, Mg2+), pose a particular concern to avoid scaling in heat‐transfer equipment, foulingz in membranes, and high consumption of detergents and sequestering chemicals in cooling and wash water. In general, ion exchange processes used to remove hardness generate concentrated brine or mineral acid as a waste regenerant stream. Residuals management and long‐term sustainability issues will continue to be major concerns with these processes. The subject paper reports and discusses the results and attributes of two new separation processes using ion exchange fibers (IX‐fibers). The first process involves the selective removal of arsenic using hybridized IX‐fibers that contain dispersed hydrated ferric oxide (HFO) nanoparticles. Anion‐exchanger‐supported HFO particles offered a high arsenic removal capacity; less than 10% of influent arsenic broke through after 30,000 bed volumes. Hybrid fibers were also amenable to efficient regeneration with 2% NaOH and 2% NaCl and capable of simultaneous removal of both arsenic(V) and arsenic(III). The second process involves the environmentally benign removal of hardness. Most importantly, this process uses harvested snowmelt (or rainwater) sparged with carbon dioxide as the regenerant. Consequently, the spent regenerant does not contain a high concentration of aggressive chemicals such as sodium chloride or acid like traditional ion‐exchange processes nor does the process produce voluminous sludges as does lime softening. The bulk of carbon dioxide consumed during regeneration remains sequestered in the aqueous phase as alkalinity. For both treatment strategies, IX‐fibers form the heart of the process. They are essentially thin cylindrical polymeric strands 10–20 μm in diameter with functional groups residing near to the fiber surface. Low intraparticle diffusional resistance is the underlying reason why calcium loaded weak acid IX‐fibers are amenable to efficient regeneration using either snowmelt or rainwater sparged with carbon dioxide. Additionally, for hybrid IX‐fibers, enhanced adsorption kinetics may offer the possibility for certain point of use applications, which are unavailable to their resin counterparts. © 2006 American Institute of Chemical Engineers Environ Prog, 2006
A simple procedure to approximate slip displacement of freestanding rigid body subjected to earthquake motions
Authors: Taniguchi Tomoyo , Miwa Takuya 
Published: October 2006

AbstractA simple calculation procedure for estimating absolute maximum slip displacement of a freestanding rigid body placed on the ground or floor of linear/nonlinear multi‐storey building during an earthquake is developed. The proposed procedure uses the displacement induced by the horizontal sinusoidal acceleration to approximate the absolute maximum slip displacement, i.e. the basic slip displacement. The amplitude of this horizontal sinusoidal acceleration is identical to either the peak horizontal ground acceleration or peak horizontal floor response acceleration. Its period meets the predominant period of the horizontal acceleration employed. The effects of vertical acceleration are considered to reduce the friction force monotonously. The root mean square value of the vertical acceleration at the peak horizontal acceleration is used. A mathematical solution of the basic slip displacement is presented. Employing over one hundred accelerograms, the absolute maximum slip displacements are computed and compared with the corresponding basic slip displacements. Their discrepancies are modelled by the logarithmic normal distribution regardless of the analytical conditions. The modification factor to the basic slip displacement is quantified based on the probability of the non‐exceedence of a certain threshold. Therefore, the product of the modification factor and the basic slip displacement gives the design slip displacement of the body as the maximum expected value. Since the place of the body and linear/nonlinear state of building make the modification factor slightly vary, ensuring it to suit the problem is essential to secure prediction accuracy. Copyright © 2006 John Wiley & Sons, Ltd.
Shape reconstruction from medical images and quality mesh generation via implicit surfaces
Authors: Peiró J. , Formaggia L. , Gazzola M. , Radaelli A. , Rigamonti V. 
Published: October 2006

AbstractThe ability of automatically reconstructing physiological shapes, of generating computational meshes, and of calculating flow solutions from medical images is enabling the introduction of computational fluid dynamics (CFD) techniques as an additional tool to aid clinical practice.This article presents a set of procedures for the shape reconstruction and triangulation of geometries derived from a set of medical images representing planar cross sections of the object. The reconstruction of the shape of the boundary is based on the interpolation of an implicit function through a set of points obtained from the segmentation of the images. This approach is favoured for its ability of smoothly interpolating between sections of different topology. The boundary of the object is an iso‐surface of the implicit function that is approximated by a triangulation extracted by the method of marching cubes. The quality of this triangulation is often neither suitable for mesh generation nor for flow solution. We discuss the use of mesh enhancement techniques to maximize the quality of the triangulation together with curvature adaption to optimize mesh resolution.The proposed methodology is applied to the reconstruction and discretization of two physiological geometries: a femoral by‐pass graft and a nasal cavity. Copyright © 2006 John Wiley & Sons, Ltd.
Health systems in East Asia: what can developing countries learn from Japan and the Asian Tigers?
Authors: Wagstaff Adam 
Published: October 2006

AbstractThe health systems of Japan and the Asian Tigers (Hong Kong, Korea, Singapore and Taiwan), and the recent reforms to them, provide many potentially valuable lessons to East Asia's developing countries. All five systems have managed to keep a check on health spending despite their different approaches to financing and delivery. These differences are reflected in the progressivity of health finance, but the precise degree of progressivity of individual sources and the extent to which households are vulnerable to catastrophic health payments depend on the design features of the system – the height of any ceilings on social insurance contributions, the fraction of health spending covered by the benefit package, the extent to which the poor face reduced copayments, whether there are caps on copayments, and so on. On the delivery side, too, Japan and the Tigers offer some interesting lessons. Singapore's experience with corporatizing public hospitals – rapid cost and price inflation, a race for the best technology, and so on – illustrates the difficulties of corporatization. Korea's experience with a narrow benefit package illustrates the danger of providers shifting demand from insured services with regulated prices to uninsured services with unregulated prices. Japan, in its approach to rate setting for insured services, has managed to combine careful cost control with fine‐tuning of profit margins on different types of care. Experiences with DRGs in Korea and Taiwan point to cost‐savings but also to possible knock‐on effects on service volume and total health spending. Korea and Taiwan both offer important lessons for the separation of prescribing and dispensing, including the risks of compensation costs outweighing the cost savings caused by more ‘rational’ prescribing, and cost‐savings never being realized because of other concessions to providers, such as allowing them to have onsite pharmacists. Copyright © 2006 John Wiley & Sons, Ltd.
Reactions of Alkyl Radicals with Substituted Toluenes and the Effect of Substituents on Dissociation Energies of Benzyl CH Bonds
Authors: Arafat Abdelfattah M. , Mathew Samuel K. , Akintobi Solademi O. , Zavitsas Andreas A. 
Published: October 2006

AbstractReactions of isopropyl and of undecyl radicals with meta‐ and para‐substituted toluenes are reported. The results demonstrate that the reactivities of toluenes are due to both benzyl‐H abstraction and addition of the alkyl radicals to the aromatic ring. Relative reactivities yield curved Hammett plots, consistent with kinetic data reported by Dütsch and Fischer. Abstractions and ring additions occur with comparable rates, but opposite Hammett slopes. Addition is favored by electron‐withdrawing and abstraction by electron‐donating substituents. The effects of substituents on the dissociation energies of benzyl CH bonds are shown to be the major factor influencing reaction rates for benzyl‐H abstraction by alkyl radicals.
2,5‐Dihydro‐1H‐imidazole‐Based Nitroxides as Prospective Mediators in Living Radical Polymerization
Authors: Zubenko Dmitry , Kirilyuk Igor , Roshchupkina Galina , Zhurko Irina , Reznikov Vladimir , Marque Sylvain R. A. , Bagryanskaya Elena 
Published: October 2006

AbstractA number of spectroscopic methods were applied to obtain kinetic parameters of reactions modelling the 2,5‐dihydro‐1H‐imidazole 1‐oxide mediated living polymerization of acrylates. The homolysis rate constants of alkoxyamines based on five nitroxides were measured by EPR spectroscopy at different temperatures. The recombination rate constants kc between the corresponding alkyl radicals and the nitroxides were measured by means of laser flash photolysis. The time‐resolved chemically induced dynamic nuclear polarization (TR‐CIDNP) experiments revealed the negligible contribution of disproportionation in the recombination reaction. In addition, the thermodecomposition of alkoxyamines in the NMR probe showed the absence of intramolecular elimination of hydroxylamines from the corresponding alkoxyamines. Analysis of the kinetic parameters showed that the 2,5‐dihydro‐1H‐imidazole 1‐oxide type radicals are promising mediators for the living polymerization of acrylates and methacrylates.
Modification of Guanine with Photolabile N‐Hydroxypyridine‐2(1H)‐thione: Monomer Synthesis, Oligonucleotide Elaboration, and Photochemical Studies
Authors: Vrantza Despoina , Kaloudis Panagiotis , Leondiadis Leondios , Gimisis Thanasis , Vougioukalakis Georgios C. , Orfanopoulos Michael , Gasparutto Didier , Cadet Jean , Encinas Susana , Paris Cecilia , Miranda Miguel A. 
Published: October 2006

AbstractThe photochemistry of N‐hydroxypyridine‐2(1H)‐thione (NHPT), inserted as a photolabile modifier at the 6‐position of 2′‐deoxyguanosine or guanosine, has been evaluated. In particular, 6‐[(1‐oxidopyridin‐2‐yl)sulfanyl]‐ (1a) and 6‐[(pyridin‐2‐yl)sulfanyl]‐2′,6‐dideoxyguanosine (2a), novel photolabile derivatives of the natural nucleosides, were synthesized and characterized. The observed photolysis products of 1a in organic solvents could only be rationalized by assuming a rapid equilibrium with the corresponding 6‐[(2‐thioxopyridin‐1(2H)‐yl)oxy] analogue 3a (Scheme 5). Transient spectroscopy of 1a indicated a strong triplet‐excited state suitable for triplet → triplet energy transfer or singlet‐oxygen generation. The NHPT function was stable enough for (slightly modified) automated solid‐phase oligonucleotide synthesis. The utility of the above compounds is discussed, as well as their potential use in photosensitization of reactive oxygen species in DNA.
The Reaction of Peroxynitrite with Morpholine (Secondary Amines) Revisited: The Overlooked Hydroxylamine Formation
Authors: Kirsch Michael , Korth Hans‐Gert , Wensing Angela , Lehnig Manfred , Sustmann Reiner , de Groot Herbert 
Published: October 2006

AbstractThe reaction of peroxynitrite/peroxynitrous acid with morpholine as a model compound for secondary amines is reinvestigated in the absence and presence of carbon dioxide. The concentration‐ and pH‐dependent formation of N‐nitrosomorpholine and N‐nitromorpholine as reported in three previous papers ([25] [26] [14]) is basically confirmed. However, 13C‐NMR spectroscopic product analysis shows that, in the absence of CO2, N‐hydroxymorpholine is, at pH ≥ 7, the major product of this reaction, even under anaerobic conditions. The formation of N‐hydroxymorpholine has been overlooked in the three cited papers. Additional (ring‐opened) oxidation products of morpholine are also detected. The data account for radical pathways for the formation of these products via intermediate morpholine‐derived aminyl and α‐aminoalkyl radicals. This is further supported by EPR‐spectrometric detection of morpholine‐derived nitroxide radicals, i.e., morpholin‐4‐yloxy radicals. N‐Nitrosomorpholine, however, is very likely formed by electrophilic attack of peroxynitrite‐derived N2O4. 15N‐CIDNP Experiments establish that, in the presence of CO2, N‐nitro‐ and C‐nitromorpholine are generated by radical recombination. The present results are in full accord with a fractional (28 ± 2%) homolytic decay of peroxynitrite/peroxynitrous acid with release of free hydroxyl and nitrogen dioxide radicals.
Proton‐Coupled Electron Transfer of Unsaturated Fatty Acids and Mechanistic Insight into Lipoxygenase
Authors: Fukuzumi Shunichi 
Published: October 2006

AbstractA proton‐coupled electron transfer (PCET) process plays an important role in the initial step of lipoxygenases to produce lipid radicals which can be oxygenated by reaction with O2 to yield the hydroperoxides stereoselectively. The EPR spectroscopic detection of free lipid radicals and the oxygenated radicals (peroxyl radicals) together with the analysis of the EPR spectra has revealed the origin of the stereo‐ and regiochemistry of the reaction between O2 and linoleyl (= (2Z)‐10‐carboxy‐1‐[(1Z)‐hept‐1‐enyl]dec‐2‐enyl) radical in lipoxygenases. The direct determination of the absolute rates of H‐atom‐transfer reactions from a series of unsaturated fatty acids to the cumylperoxyl (= (1‐methyl‐1‐phenylethyl)dioxy) radical by use of time‐resolved EPR at low temperatures together with detailed kinetic investigations on both photoinduced and thermal electron‐transfer oxidation of unsaturated fatty acids provides the solid energetic basis for the postulated PCET process in lipoxygenases. A strong interaction between linoleic acid (= (9Z,12Z)‐octadeca‐9,12‐dienoic acid) and the reactive center of the lipoxygenases (FeIIIOH) is suggested to be involved to make a PCET process to occur efficiently, when an inner‐sphere electron transfer from linoleic acid to the FeIII state is strongly coupled with the proton transfer to the OH group.
Interaction between Molecular Oxygen and Nitroxide Radicals: A Search for a Reversible Complex
Authors: Moscatelli Alberto , Ottaviani M. Francesca , Adam Waldemar , Buchachenko Anatoly , Jockusch Steffen , Turro Nicholas J. 
Published: October 2006

AbstractAt high concentrations of oxygen, the EPR spectrum of the nitroxide radical 4‐oxo‐TEMPO (= 4‐oxo‐2,2,6,6‐tetramethylpiperidin‐1‐yloxy) is found to broaden significantly. In addition to the expected broadening, double integration of the EPR signals indicates that a significant fraction of the nitroxide spins has ‘disappeared’. In perfluoro(2‐butyltetrahydrofuran) at 273 K, the extent of diminution of the EPR signal intensity is ca. 20%. The results are analyzed in terms of collision and supramolecular complexes between oxygen and 4‐oxo‐TEMPO. It is concluded that a supramolecular complex is responsible for the observed phenomenon.
The Persistent Radical Effect: From Mechanistic Curiosity to Synthetic Tool
Authors: Focsaneanu Kathy‐Sarah , Scaiano Juan C. 
Published: October 2006

AbstractThe Fischer–Ingold persistent radical effect (PRE) provides a simple conceptual framework to rationalize reactivities in systems involving two radicals with very different self‐reaction rate constants; in a limiting, but rather common case, one of these radicals is persistent at room temperature. In these cases, the cross‐coupling product is strongly favored. This contribution summarizes some of the work carried out at the University of Ottawa, where the PRE plays a key role in determining product distributions. Much of this work was inspired by the seminal contributions of Hanns Fischer.
Photo‐CIDNP Studies of Hydroxy Ketones and Higher‐Molecular‐Weight Systems
Authors: Bargon Joachim , Kuhn Lars T. 
Published: October 2006

AbstractIn situ NMR spectroscopy can be applied to investigate chemical reactions during which free radicals occur as intermediates. In chemical systems of low molecular weight, nuclear‐spin polarization results from the spin selectivity of free‐radical reactions, because a pair of radicals has to obey the exclusion principle according to Pauli; therefore, this system reacts in a spin‐selective manner when forming a chemical single bond. As a consequence, strong transient absorption and emission lines occur in the NMR spectra acquired during free‐radical reactions. This phenomenon is known as ‘chemically induced dynamic nuclear polarization’ (CIDNP). However, long correlation times associated with short proton spin–lattice relaxation times T1 render it difficult to observe CIDNP in macromolecules. Therefore, in these and in many other cases, it can be attractive to utilize the simultaneously occurring heteronuclear polarization or to selectively transfer the 1H polarization to heteronuclei, since their T1 times can be substantially shorter than those of protons.In this paper, we present examples of how CIDNP can be observed both in low‐molecular‐weight systems as well as in systems exhibiting a rather macromolecular character. Also, CIDNP can assist in obtaining useful information about macromolecular systems that normally is very difficult to obtain otherwise. Since CIDNP is primarily a qualitative method by which free‐radical intermediates may be identified, we have developed a procedure allowing the quantitative determination of the magnetic properties of the intermediate free radicals. This process is especially useful for very short‐lived radicals, which are frequently elusive to ESR spectroscopy conducted in solution. In particular, g values of a variety of radical ions have been determined in this fashion by CIDNP‐NMR spectroscopy. The data thus obtained provide an alternative to ESR and, hence, complement this traditional method (manuscript in preparation).