bluuebunny/crossref_metadata_2025_split huggingface dataset:
Global preordering for Newton equations using model hierarchy
Authors: Abbott Kirk A. , Allan Benjamin A. , Westerberg Arthur W. 
Published: June 2004

AbstractIn solving large simulation problems using Newton's method, a large sparse linear system Ax = b has to be solved. The cost of solving its problems can dominate the overall solution cost of the problem. Current approaches of reducing these costs are reviewed, and then a new algorithm for preordering the sparse matrix A is described that is based on the hierarchical structure provided by an object‐oriented description of many recent modeling systems such as ASCEND, gPROMS, DIVA, and Omola. Particularly, rapid preorderings are obtained to support interactive manipulation of models and efficient solutions in automatic process synthesis algorithms, two applications where the preordering cost will be spread over only a few factorizations. With a factorization routine that permits a‐priori reorderings (LU1SOL), this algorithm produces order of magnitude reductions in analysis and factoring times as well as in fill and operation count over our previous experience. The time to factor the 50,000 Newton equations for a highly recycled ethylene plant model is of the order of a few seconds on a conventional workstation. Abstracting and applying the fundamental concepts of this algorithm made it possible to improve the performance of the ma28 code significantly. This approach makes solution speeds competitive with and generally more consistent than codes considered the state‐of‐the‐art (ma48 and umfpack 1.0).
Role of depletion and surface‐induced structural forces in bidisperse suspensions
Authors: Xu W. , Nikolov A. D. , Wasan D. T. 
Published: June 2004

AbstractDepletion and structural interactions between dilute, large, nearly hard‐sphere colloidal particles in a fluid dispersion containing much smaller nearly hard spheres were investigated as a function of small‐particle concentration in sedimentation experiments. It shows that low concentrations of fine particles can destabilize larger particles due to the attractive depletion forces, while at higher concentrations of small particles, the surface‐induced structural forces prevent large‐size particles from approaching each other and thereby stabilize the large‐particle suspension. A theoretical model based on the Ornstein–Zernike method was used to calculate the interparticle interactions in a bidis‐persed colloidal system in which small particles are polydispersed. The theoretical re‐sults explain the experimental observations.
FTIR method for VLE measurements of acid‐gas–alkanolamine systems
Authors: Rogers William J. , Bullin Jerry A. , Davison Richard R. , Frazier Richard E. , Marsh Kenneth N. 
Published: June 2004

AbstractThe standard industrial process for the purification of natural gas is to remove acid gases, mainly hydrogen sulfide and carbon dioxide, by the absorption and reaction of these gases with alkanolamines, but the lack of reliable and accurate vapor‐liquid equilibrium (VLE) data impedes the commercial application of more efficient alkanolamine systems. The objective of this research was to develop an FTIR apparatus and an in‐situ technique capable of making VLE measurements of acid‐gas–aqueous alkanolamine systems and to improve the accuracy of vapor–liquid equilibrium measurements at low hydrogen sulfide and carbon dioxide concentrations. The new FTIR apparatus and technique were tested in VLE measurements of low concentrations of carbon dioxide and hydrogen sulfide in aqueous mixtures of diethanolamine.
Ionizable interpenetrating polymer networks of carboxymethyl cellulose and polyacrylic acid: Evaluation of water uptake
Authors: Bajpai A. K. , Mishra Abhilasha 
Published: June 2004

AbstractA semi interpenetrating polymer network (IPN) of carboxymethyl cellulose (CMC) and crosslinked polyacrylic acid (PAA) has been prepared and its water‐sorption capacity has been evaluated as a function of chemical architecture of the IPN, pH, and temperature of the swelling medium. The water uptake potential of the IPNs has also been investigated in inorganic salt containing aqueous solutions and simulated biological fluids. The IPN was characterized by IR spectral analysis, and the network parameters such as average molecular weight between crosslinks (Mc), crosslink density (q), and number of elastically effective chains (Ve) have been evaluated by water‐sorption measurements. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2054–2065, 2004
Subectodermal microfibrillar bundles are organized into a distinct parallel array in the developing chick limb bud
Authors: Isokawa Keitaro , Sejima Hitomi , Shimizu Osamu , Yamazaki Yosuke , Yamamoto Koji , Toda Yoshihisa 
Published: June 2004

AbstractIn this study, a unique fiber system in the subectodermal mesenchyme of the chick limb bud was visualized immunohistochemically with the use of a novel monoclonal antibody termed “FB1.” This antibody stained a subset of extracellular fibers in the embryonic mesenchyme. Among the fibers visualized, those running perpendicularly to the limb bud ectoderm became progressively prominent in their thickness and length, and organized into a parallel array in the subectodermal region. This fiber system was distinct from that of major collagens, fibronectin, or tenascin. A molecule immunoprecipitated with FB1 comigrated with JB3 antigen, or chicken fibrillin‐2. The fibers visualized immunohistochemically by FB1 and JB3 were indistinguishable from each other, and ultrastructurally appeared to be bundles composed of tubular‐like microfibrils that originated directly from the ectodermal basal lamina. They lacked the amorphous deposits that are characteristic of elastin. A similar array of subectodermal fibers was also found in the developing axilla and some truncal regions, again well before the development of a definitive dermis. These findings suggest that a parallel array of subectodermal FB1‐positive fibers constitutes a precocious fiber system in the presumptive dermis prior to the substantial formation of collagenous fibers. These fibers could be developmentally linked to oxytalan fibers, which are known to be present in the papillary dermis in mature cutaneous tissue. © 2004 Wiley‐Liss, Inc.
Expression of the Ellis‐van Creveld (Evc) gene in the rat tibial growth plate
Authors: Tsuji Takehito , Nakamura Hiroaki , Hirata Azumi , Yamamoto Toshio 
Published: June 2004

AbstractEllis‐van Creveld (EvC) syndrome is an autosomal recessive chondrodysplasia characterized by short limbs, postaxial polydactyly, natal teeth, and dysplastic nails. The Ellis‐van Creveld (EVC) gene, which is mutated in patients with EvC syndrome, has been identified by positional cloning. However, the physiological roles of the EVC gene have not been elucidated. Histopathological analyses of EvC syndrome have shown disturbed chondrocytic phenotypes during cartilage development. We therefore postulated that the EVC gene is a critical factor for chondrocytes during endochondral ossification. The present study focuses on the relationship between the Evc gene and chondrocytes, and examines Evc gene expression in the rat tibial growth plate at the mRNA and protein levels. Evc mRNA in tibial epiphyseal cartilage was expressed at postnatal day (P) 1, P28, and P56 by RT‐PCR. Immunohistochemical analyses localized the Evc protein mainly in prehypertrophic and hypertrophic chondrocytes of the epiphyseal growth plate in the tibia during the embryonic and postnatal periods. Evc mRNA was also detected in prehypertrophic and hypertrophic chondrocytes by in situ hybridization. These results indicate that the Evc gene functions mainly in the prehypertrophic and hypertrophic chondrocytes of the epiphyseal growth plate. The data presented here are important for future studies of the underlying mechanism of chondrodysplasia in EvC syndrome. © 2004 Wiley‐Liss, Inc.
Discarding multidrug resistance inducers, the possible role of a biosensing reporter in antimicrobial discovery
Authors: Galluzzi Lorenzo , Virtanen Pekka , Karp Matti 
Published: June 2004

AbstractThe aim of the present work was to determine whether the luminescence‐based reporter plasmid pQacLux could be applied to drug discovery in order to discard compounds with deﬁned properties. Non‐pathogenic Staphylococcus aureus RN4220 cells bearing pQacLux were incubated with different concentrations of a disinfectant of common use in hospitals. The in vivo light emission response of the plasmid to the given stimuli was then quantiﬁed and compared to a negative control for the construction of dose–response curves. The selected disinfectant provided a convenient model for the activity of quaternary ammonium compounds. In spite of the use of a raw model solution, the system revealed high levels of sensitivity. According to the results obtained, pQacLux could be conveniently used in the ﬁrst steps of drug development in order to discard all possible multidrug resistance inducers. Copyright © 2004 John Wiley & Sons, Ltd.
Detection of C677T mutation in methylenetetrahydrofolate reductase gene by denaturing high performance liquid chromatography
Authors: Fang Nenghu , Lin Li , Ren Jicun , Wu Dan 
Published: June 2004

AbstractIn this paper, we described an assay for the detection of the C677T mutation in the methylenetetrahydrofolate reductase (MTHFR) gene using denaturing high‐performance liquid chromatography (DHPLC). The conditions for DHPLC analysis were systematically investigated based on a general HPLC instrument (Prostar VARIAN). A 225 bp DNA fragment covering the 677 site of MTHFR gene was ampliﬁed by PCR technology using the puriﬁed DNA from whole blood or whole blood as template DNA. PCR products were directly injected without the need for puriﬁcation. The C677T mutation could be clearly distinguished by DHPLC technology. Our data demonstrated that DHPLC was a powerful and alternative tool for detection of genetic variants and single‐nucleotide polymorphisms to electrophoresis technology. Copyright © 2004 John Wiley & Sons, Ltd.
Simultaneous determination of YM‐64227, a phosphodiesterase type 4 inhibitor, and its ﬁve metabolites in dog plasma by high‐performance liquid chromatography with ﬂuorescence detection
Authors: Tenmizu Daisuke , Fukunaga Yasuhisa , Noguchi Kiyoshi , Kamimura Hidetaka 
Published: June 2004

AbstractWe developed and validated a reversed‐phase high‐performance liquid chromatographic method with ﬂuorescence detection for the simultaneous determination of YM‐64227 [4‐cyclohexyl‐1‐ethyl‐7‐methylpyrido(2,3‐d)pyrimidin‐2‐(1H)‐one], a novel and selective phosphodiesterase type 4 inhibitor, and its ﬁve hydroxylated metabolites in dog plasma. The plasma samples were extracted with tert‐butyl methyl ether under alkali conditions. The analytes were well separated on a phenyl ethyl column (5 µm, 250 × 4.6 mm i.d.), opreating at 40°C and using an acetonitrile–acetic acid gradient at a ﬂow rate of 1.0 mL/min. The ﬂuorescence signal was monitored at an excitation and emission wavelength of 330 and 400 nm, respectively. No interfering peak was observed at the retention time of YM‐64227, its metabolites or the internal standard. The validated quantitation range of the method was 0.4–200 ng/mL for all analytes using 0.5 mL of the plasma sample. The recovery of analytes in the extraction process was more than 65.5%. The intra‐ and inter‐assay precision was less than 5.1 and 12.6%, respectively, and the intra‐ and inter‐assay accuracy ranged from ‐8.1 to 11.8% and ‐8.0 to 9.9%, respectively. Using this assay, the plasma concentration of YM‐64227 and metabolites can be determined after the oral administration of YM‐64227 to beagle dogs. Copyright © 2004 John Wiley & Sons, Ltd.
Clinical outcomes for sirolimus‐eluting stent implantation and vascular brachytherapy for the treatment of in‐stent restenosis
Authors: Saia Francesco , Lemos Pedro A. , Hoye Angela , Sianos Georgios , Arampatzis Chourmouzios A. , de Feyter Pim J. , van der Giessen Willem J. , Smits Pieter C. , van Domburg Ron T. , Serruys Patrick W. 
Published: June 2004

AbstractThe purpose of this study was to compare the mid‐term clinical outcome of sirolimus‐eluting stent (SES) implantation and vascular brachytherapy (VBT) for in‐stent restenosis (ISR). We assessed the 9‐month occurrence of major adverse cardiac events (MACE) in 44 consecutive patients with ISR treated with SES implantation and 43 consecutive patients treated with VBT in the period immediately prior. Baseline clinical and angiographic characteristics of the two groups were similar. During follow‐up, three patients (7%) died in the VBT group and none in the SES group. The incidence of myocardial infarction was 2.3% in both groups. Target lesion revascularization was performed in 11.6% of the VBT patients and 16.3% of the SES patients (P = NS). The 9‐month MACE‐free survival was similar in both groups (79.1% VBT vs. 81.5% SES; P = 0.8 by log rank). The result of this nonrandomized study suggests that sirolimus‐eluting stent implantation is at least as effective as vascular brachytherapy in the treatment of in‐stent restenosis. Catheter Cardiovasc Interv 2004;62:283–288. © 2004 Wiley‐Liss, Inc.
Cardiovascular drugs: Adenosine role in coronary syndromes and percutaneous coronary interventions
Authors: Rosales Oscar R. , Eades Brian , Assali Abid R. 
Published: June 2004

AbstractAdenosine is an endogenous nucleoside available for the diagnosis and treatment of various cardiovascular conditions. It may be given for pharmacologic stress tests as well as administered directly into the coronary arteries during cardiac catheterization. The latter treatment may be utilized to measure fractional flow reserve in addition to treating the no‐reflow phenomenon. Adenosine has also been shown to improve the clinical outcome of thrombolytics given in the setting of acute myocardial infarction. Adenosine is a useful agent for evaluation and treatment of the cardiovascular system. Catheter Cardiovasc Interv 2004;62:358–363. © 2004 Wiley‐Liss, Inc.
Initial experience with the novel 6 Fr‐compatible system for debulking de novo coronary arterial lesions
Authors: Ikeno Fumiaki , Abizaid Alexandre , Suzuki Takeshi , Rezaee Mehrdad , Patterson Greg R. , Yeung Alan C. , Virmani Renu , Sousa J. Eduardo , Carter Andrew J. 
Published: June 2004

AbstractThe purpose of this study was to determine the efficacy of a novel system for debulking of de novo native coronary arterial lesions. The Helixciser De Novo system is a novel 6 Fr‐compatible catheter with a cutter encased in a slotted‐orifice housing to excise atheromatous plaque. The cutter rotates at 15,000 rpm, debulking the plaque as it tracks through the lesion over a straight wire or a self‐expanding nitinol helical‐shaped wire. The tissue is aspirated via an Archimedes screw pump to vacuum collection chamber. The device was evaluated in a porcine toxic coronary stent model of chronic occlusion and in five patients with focal de novo native coronary arterial lesions. Procedural variables along with outcomes were reviewed. Quantitative angiography (QCA) and volumetric intravascular ultrasound (IVUS) analysis were performed. In a porcine model of chronic occlusion, QCA demonstrated pretreatment minimal lumen diameter (MLD) increased from 0.77 ± 0.59 to 1.88 ± 0.25 mm postdebulking. IVUS analysis demonstrated pretreatment lumen volume (LV) increased from 15.8 ± 22.2 to 46.4 ± 28.9 mm3 postdebulking. In human clinical feasibility cases, QCA demonstrated pretreatment MLD increased from 0.96 ± 0.40 to 2.04 ± 0.19 mm postdebulking. IVUS analysis demonstrated pretreatment LV increased from 38.40 ± 12.78 to 52.05 ± 15.68 mm3 postdebulking. Preliminary results document the feasibility of Helixcision De Novo for treatment of focal de novo native coronary arterial lesions. Quantitative angiographic and IVUS analysis indicate that this system can effectively debulk plaque from selected noncalcified atherosclerotic lesions and thus may represent an alternative treatment strategy for coronary artery disease. Catheter Cardiovasc Interv 2004;62:308–317. © 2004 Wiley‐Liss, Inc.
Nonsurgical pulmonary valve replacement: Why, when, and how?
Authors: Khambadkone Sachin , Bonhoeffer Philipp 
Published: June 2004

AbstractPercutaneous transcatheter interventions for valve replacement or implantation is one of the most exciting developments in the field of interventional cardiology. Valvular stenosis has been treated by balloon dilatation with early and late results; however, treatment for valvular regurgitation has remained surgical until now. Most new designs have been investigated for implantation of valves in the left or right ventricular outflow tracts. Patients with surgery on the right ventricular outflow tract for congenital heart disease constitute the most common group for reoperations during late follow‐up. Surgical pulmonary valve replacement can be performed with low mortality; however, it sets up a substrate for future operations. Also, the risk of cardiopulmonary bypass, infection, bleeding, and ventricular dysfunction remains. A transcatheter technique is likely to have more acceptance and may expand the indications for early intervention for right ventricular outflow tract dysfunction. Catheter Cardiovasc Interv 2004;62:401–408. © 2004 Wiley‐Liss, Inc.
Structural determinations by circular dichroism spectra analysis using coupled oscillator methods: An update of the applications of the DeVoe polarizability model
Authors: Superchi Stefano , Giorgio Egidio , Rosini Carlo 
Published: June 2004

AbstractThe exciton (coupled oscillator) model for optical activity is a very useful and powerful method which allows to analyze a circular dichroism (CD) spectrum in a nonempirical way, arriving at a safe assignment of the absolute configuration of organic and inorganic compounds. Usually in this model only the exciton coupling of two electrically allowed transitions (oscillators) is taken into account. This approach has the important advantage of an easy application but, sometimes, it may lead to wrong results. Thus, in this review article a more general treatment, which allows considering the simultaneous coupling of several oscillators, i.e., the DeVoe model, is presented and critically analyzed, discussing in detail the latest applications reported in the literature. In the authors opinion, since the DeVoe model joins generality and reliability requiring an almost negligible computational effort, it represents the method of choice for stereochemical assignments, even by nonspecialists. Chirality 16:422–451, 2004. © 2004 Wiley‐Liss, Inc.
Signaling assemblies formed in mast cells activated via Fcϵ receptor I dimers
Authors: Dráberová Lubica , Lebduška Pavel , Hálová Ivana , Tolar Pavel , Štokrová Jitka , Tolarová Helena , Korb Jan , Dráber Petr 
Published: June 2004

AbstractAlthough aggregation of the Fcϵ receptor I (FcϵRI) is necessary for Ag‐mediated mast cell triggering, the relationship between the extent of the FcϵRI aggregation and subsequent biochemical and topographical events is incompletely understood. In this study, we analyzed the activation events induced by FcϵRI dimers, elicited by binding of anti‐FcϵRI mAb to rat basophilic leukemia cells. We found that, in contrast to extensively aggregated FcϵRI, receptor dimers (1) induced a less extensive association of FcϵRI with detergent‐resistant membranes, (2) delayed the tyrosine phosphorylation and membrane recruitment of several signaling molecules, (3) triggered a slower but more sustained increase in concentration of free cytoplasmic calcium, (4) induced degranulation which was not inhibited at higher concentrations of the cross‐linking mAb, and (5) failed to produce clusters of FcϵRI, Syk kinase and Grb2 adapter in osmiophilic membranes, as detected by immunogold electron microscopy on membrane sheets. Despite striking differences in the topography of FcϵRI dimers and multimers, biochemical differences were less pronounced. The combined data suggest that FcϵRI‐activated mast cells propagate signals from small signaling domains formed around dimerized/oligomerized FcϵRI; formation of large FcϵRI aggregates in osmiophilic membranes seems to promote both strong receptor triggering and rapid termination of the signaling responses.
A conserved sequence in the mouse variable T cell receptor α recombination signal sequence 23‐bp spacer can affect recombination
Authors: Probst Jochen , Blumenthal Sibylle G. , Tenzer Stefan , Weinschenk Toni , Dittmer Jürgen , Schoor Oliver , Six Adrien , Rammensee Hans‐Georg , Pascolo Steve 
Published: June 2004

AbstractAlthough the V‐gene segments coding for the TCR α and δ chains are mixed together in the α δ locus and are recombined by the same processes, some gene segments (TRAV) are rearranged only with TCR Jα gene segments, some (TRDV) only with TCR Dδ gene segments and some (TRADV) with both. To date, no molecular signal is known that can characterize these three differenttypes of gene segments. Studying the recombination signal sequences (RSS) of all mouse TCR V‐gene segments we observed that 80% of the TRAV contain a palindrome sequence (CTGCAG) or its related variant CTGTAG in their 23‐bp spacer. Using gel‐shift assays we show that these sequences are specifically recognized by some nuclear proteins that are expressed by fresh thymocytes, fresh lymphocytes and tumor cells. Recombination assays on plasmid substrates in a pre‐B cell line showed that RSS containing the CTGCAG sequence can impair recombination. From the protein fractions containing the CTGCAG‐binding activity, three proteins were identified: G3BP1 (a nucleic‐acid‐binding protein with a proposed helicase activity) and two proteins from the high‐mobility group (HMG) family — HMGB2 and HMGB3. We hypothesize that these proteins can affect recombination at the TCR α δ locus.
Synthesis of a Persistent 1σ3,3σ3‐Diphosphaallyl Cation Featuring a Localized Phosphorus−Carbon Double Bond
Authors: Martin David , Baceiredo Antoine , Bertrand Guy 
Published: June 2004

Abstracttert‐Butyl thiol, 2,6‐dimethylthiophenol, 2,6‐dimethylphenol, and 2,6‐bis(tert‐butyl)‐4‐methylphenol cleanly add to the 1σ4,3σ2‐diphosphacumulene 1 to afford the corresponding C‐phosphanyl phosphorus ylides 2a−d. Treatment of 2a with gallium trichloride quantitatively leads to the C‐phosphonio phosphaalkene 3, resulting from the1,3‐migration of the sulfido group. Under the same experimental conditions, cleavage of the arylthio and aryloxy groups of 2b and 2c leading to the C‐phosphonio phosphaalkene 4 is observed. In the case of the sterically most crowded derivative, 2d, abstraction of the chloride ion affords the 1σ3,3σ3‐diphosphaallyl cation 5, which is stable for several weeks in dichloromethane at −20 °C, but decomposes after a few minutes at above 0 °C. Compound 5 reacts at low temperatures with an excess of acetonitrile or benzaldehyde to afford quantitatively and regioselectively the corresponding five‐membered heterocycles 6 and 7. The NMR spectroscopy data and reactivity suggest that 5 features a localized double bond with a planar diamino‐substituted phosphorus center, and a single bond with a pyramidalized (amino)(aryloxy)phosphanyl group. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)