bluuebunny/crossref_metadata_2025 huggingface dataset:
High‐pressure three‐phase fluidization: Hydrodynamics and heat transfer
Authors: Luo Xukun , Jiang Peijun , Fan L.‐S.
Published: June 2004

The phase holdups and the heat‐transfer behavior were studied experimentally in three‐phase fluidized beds over a pressure range of 0.1–15.6 MPa. Bubble characteristics in the bed are examined by direct flow visualization. Pressure effects on the bubble coalescence and breakup are analyzed mechanistically. The study indicates that the pressure affects the hydrodynamics and heat‐transfer properties of a three‐phase fluidized bed significantly. The average bubble size decreases and the bubble‐size distribution becomes narrower with an increase in pressure. The bubble‐size reduction leads to an increase in the transition gas velocity from the dispersed bubble regime to the coalesced bubble regime, an increase in the gas holdup, and a decrease in the liquid and solids holdups. The pressure effect is insignificant above 6 MPa. The heat‐transfer coefficient between an immersed surface and the bed increases to a maximum at pressure 6–8 MPa and then decreases with an increase in pressure at a given gas and liquid flow rate. This variation is attributed to the pressure effects on phase holdups and physical properties of the gas and liquid phases. A mechanistic analysis revealed that the major heat‐transfer resistance in high‐pressure three‐phase fluidized beds resides in a liquid film surrounding the heat‐transfer surface. An empirical correlation is proposed to predict the heat‐transfer coefficient under high‐pressure conditions.
Mass transfer based on chemical potential theory: ZnSO4/H2SO4/D2EHPA
Authors: Klocker Hartmut , Bart Hans‐Jörg , Marr Rolf , MÜLler Hansjourg
Published: June 2004

A fundamental model based on chemical reaction kinetics and diffusional mass transfer for the extraction of zinc sulfate with di(2‐ethyhexyl) phosphoric acid (D2EHPA) in n‐heptane at 250 C was developed. Gradients of the chemical potential were used as the driving force for diffusion. Activity coefficients and their derivatives were calculated from the Pitzer equation in the aqueous phase, while the organic non‐ideality was considered by the Hildebrand–Scott treatment. The Nerst–Planck equation was chosen for describing the diffusion of aqueous ions, paying special care to the formation of hydrogen sulfate. It was assumed that this fast ionic reaction can be described in terms of the mass action law in the bulk and film. For the multicomponent mass transfer of the organic species, the Maxwell–Stefan theory was adopted. A kinetic equation for the extraction of zinc with D2EHPA, which considers the adsorption of the D2EHPA molecules at the interface based on the Langmuir law, was suitable for our experimental data. Organic zinc concentration vs. time was obtained in a type of Lewis cell with vibrational mixing. Molar fluxes were calculated by fitting it with rational functions, which were analytically differentiated. Initial conditions of the experiments cover a wide range of the zinc (0.1 mM to 0.05 M), D2EHPA, and sulfuric acid concentration. Experimental fluxes could be well described by this model when chemical kinetics and mass transfer were considered. In particular, the resistance to mass transfer in the organic film is important.
Dynamics of the SCR‐DeNOx reaction by the transient‐response method
Authors: Lietti Luca , Nova Isabella , Camurri Stefano , Tronconi Enrico , Forzatti Pio
Published: June 2004

The unsteady‐state kinetics of NH3 adsorption–desorption and of selective catalytic reduction (SCR) of NO with NH3 were studied over model V2O5/TiO2 and V2O5–WO3/TiO2 catalysts by transient response techniques. Over both catalysts the dynamic experiments could be successfully described by a kinetic model assuming (1) negligible NO adsorption on the catalyst surface; (2) nonactivated NH3 adsorption; (3) a Temkin‐type NH3 coverage dependence of the desorption energy; (4) a nonlinear dependence of the SCR reaction rate on the NH3 surface coverage. Thus, the results are supportive of an Eley‐Rideal mechanism for the SCR reaction and of a significant heterogeneity for adsorption–desorption process and surface reaction of the catalyst surface. The binary and ternary catalysts exhibit similar acid properties, but different activity in the SCR reaction, possibly related to the superior redox properties of the WO3‐containing sample. Over both samples the estimates of the activity energies for NH3 desorption at zero coverage and for the surface reaction of NO with NH3 are similar and in the 23–26 and 14–16 kcal/mol ranges, respectively.
Mathematical model of a pneumatic conveying dryer
Authors: Fyhr Christian , Rasmuson Anders
Published: June 2004

A model for a pneumatic‐conveying dryer is presented, with the focus on the superheated steam drying of wood chips, although it can also be used for other porous materials and drying media. It includes a comprehensive 2‐D model for the drying of single wood chips, which accounts for the main physical mechanisms occurring in wood during drying, including coupled transport of water, air, vapor and heat. This model allows for features such as initial condensation and flashing at the outlet, as well as the falling rate period when the drying is controlled by internal transport. External drying conditions in the dryer are calculated by applying mass, heat and momentum equations for each incremental step in dryer length. A plug‐flow assumption is made for the dryer model, and single‐particle and dryer models were solved iteratively. The irregular movement and nonspherical shape of wood chips are accounted for by measuring drag and heat‐transfer coefficients.

Model calculations illustrate the complex interactions among steam, particles, and walls that occur in a flash dryer. The drying rate, the slip velocity, and temperature vary in a complex manner through the dryer, necessitating the use of a comprehensive single‐particle model, as in this case. Previous experimental data on the drying of bark chips in a pilot dryer was used to verify the model. The predicted temperature and pressure profiles, as well as the final moisture content of the material, agreed well with the measurements. Thus, the model provides a useful tool for the design and scale‐up of pneumatic‐conveying dryers. Effects of steam and material properties on the drying were investigated with different design parameters.
Experimental study of the flow in the metering nip of a metering‐size press
Authors: Réglat O. , Tanguy P. A.
Published: June 2004

The metering operation in the transfer‐roll coating process is crucial for achieving a good uniformity and suitable thickness of the coating film. Experimental results carried out on a laboratory coater are reported. This coater mimics industrial flow conditions: it has a transfer roll and a metering‐rod diameter similar to those found on a pilot coater, it operates at commercial speed, and the cover of the transfer roll is deformable. The experimental apparatus is described first. Then, a video analysis of the rib pattern is presented. Some interesting features are shown, in particular the existence of an inertia regime at high speed. The nip flow hydrodynamics are investigated using measurements of the pressure profile. It is shown that the film stability is strongly linked to the flow at the exit of the nip. The analysis of the maximum pressure in the nip, for various fluid viscosities and operating parameters, is represented using a master curve.
Polymer‐solute diffusion and equilibrium parameters by inverse gas chromatography
Authors: von Meien Oscar F. , Biscaia Evaristo C. , Nobrega Ronaldo
Published: June 2004

Inverse gas chromatography (IGC) was used to measure diffusion and thermodynamic parameters of volatile compounds in polymers. A comprehensive model for IGC is proposed, and a numerical solution for it is developed. Four capillary columns were prepared using PDMS and EPDM as the stationary phase. Toluene, ethanol, water, and some chlorinated compounds were the probes for the chromatographic experiments. Limitations of the IGC technique, although not reported in the literature, are explained. Nevertheless, the results for the systems chosen were satisfactory and agreed with the literature. The effect of adsorption on the column wall is important when water is used as a solute. The adsorption effect was incorporated into the model. The parameters obtained for water using the modified model became more reliable. The parameters obtained with IGC were used to get further understanding of the pervaporation process.
Effect of the flow rates in linear, ideal, simulated moving‐bed chromatography
Authors: Zhong Guoming , Smith Maureen S. , Guiochon Georges
Published: June 2004

The algebraic solution for linear, ideal simulated moving‐bed (SMB) chromatography derived previously revealed important new properties of the SMB process. This solution was validated by comparing with experimental data and with the results of numerical solutions of the equilibrium–dispersive and the lumped kinetic model. This earlier solution, however, was limited to the simple case in which the safety factor was assumed to be the same for the flow rates in all four sections. An extension of this solution to the case in which the safety factors differ and allow an independent selection of the four different flow rates (within limits) is derived. This solution accounts well for most practical situations. It permits the discussion of the influence of different flow rates on the performance of an SMB unit, an issue of critical importance for the optimization of the design and operation of these separators.
Optimal alarm logic design for mass‐flow networks
Authors: Tsai Chii‐Shang , Chang Chuei‐Tin
Published: June 2004

An optimal alarm‐system design method, which takes full advantage of the inherent hardware and spatial redundancies in a mass‐flow network, is proposed. In particular, systematic procedures are developed to identify independent measurement methods for the flow rate of any stream in the process and to synthesize corresponding alarm generation logic. To implement the suggested alarm strategy, the formulas for evaluating conditional probabilities of type I and II mistakes are also derived. The results of applying the proposed alarm system to the application example show that the approach taken in this work is effective in suppressing the latter mistakes. Further, this system is superior to any of the existing alarm techniques in the sense that it can be appropriately tailored to minimize the expected loss due to misjudgments in generating alarms.
Effect of the membrane activity on the performance of a catalytic membrane reactor
Authors: Coronas J. , Gonzalo A. , Lafarga D. , Menéndez M.
Published: June 2004

A mathematical model for a catalytic membrane reactor for oxidative coupling of methane (OCM), in which the membrane acts as an oxygen distributor to a bed of catalyst, is presented. From experimental data obtained using several silica membranes impregnated with Li and/or Na, which were prepared by the sol–gel method using alumina supports, the catalytic activity of the membrane was included in the so‐called real membrane reactor (RMR) model. Then, the RMR performance was compared with that of the ideal membrane reactor (IMR), whose membrane was supposed to have no activity for the OCM and with experimental data obtained in membrane reactors. Since the membrane activity was implemented in the RMR model, for the first time in the literature, maxima in the hydrocarbon selectivity–methane conversion curves were predicted in agreement with previous experimental trends. Besides, the IMR performance was compared with that of the fixed‐bed reactor (FBR), giving the maximum improvement of a membrane reactor over the FBR. Key factors for the future improvement of the performance in this kind of membrane reactor are deduced from these simulations.
Coal liquefaction mechanism using a tritium tracer method
Authors: Godo Masazumi , Umemura Masatsune , Ishihara Atsushi , Kabe Toshiaki
Published: June 2004

To determine the behavior of hydrogen in tetralin, the reaction of tetralin with tritiated gaseous hydrogen was studied in a flow reactor at 400–450°C, 2.5–9.8 MPa for various residence times. The amount of hydrogen exchange between tetralin and tritiated hydrogen was estimated from the balance of hydrogen and tritium. Although yields of methylindan and naphthalene, and the hydrogen‐exchange ratio (HER) of tetralin increased monotonously with residence time, these values were scarcely influenced by the reaction pressure at every temperature. It was thought that the formation of tetralyl radicals in this system would be the rate‐determining step for both the conversions of tetralin into methylindan and naphthalene, and the hydrogen exchange of tetralin. Conversions of tetralin into methylindan and naphthalene, and the hydrogen‐exchange reaction using the autoclave were very close to those using the flow reactor.
Global preordering for Newton equations using model hierarchy
Authors: Abbott Kirk A. , Allan Benjamin A. , Westerberg Arthur W.
Published: June 2004

In 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

Depletion 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

The 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

A 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

In 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

Ellis‐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

The 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

In 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

We 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

The 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

Adenosine 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

The 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

Percutaneous 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

The 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

Although 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

Although 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

tert‐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)
Cationic and Neutral Rhodium(I) Oxazolinylcarbene Complexes
Authors: César Vincent , Bellemin‐Laponnaz Stéphane , Gade Lutz H.
Published: June 2004

Reaction of [Rh(μ‐OtBu)(diene)]2 [diene = 1,5‐cyclooctadiene (COD) or bicyclo[2.2.1]hepta‐2,5‐diene (NBD)] with the oxazolinylcarbene ligand precursor 2‐(4,4‐dimethyl)oxazolinylimidazolium bromide (“Me2carboxH+Br−”, 2) yielded the five‐coordinate complexes [RhBr(Me2carbox)(diene)] [diene = COD (3), NBD (4)]. Single‐crystal X‐ray structure analyses established a distorted trigonal bipyramidal configuration for 3, whereas the molecular structure of 4 is distorted square pyramidal. The dynamic properties of these five‐coordinate complexes have been investigated by variable temperature 1H NMR spectroscopy, indicating polytopal rearrangements of the five‐coordinate complexes. The two compounds were converted into the square‐planar cationic complexes [Rh(Me2carbox)(diene)]+ (5 and 6, respectively), which have been isolated and fully characterised. The rhodium complex [RhBr(Me2carbox)(CO)] (7) was obtained in high yield in a one‐step reaction of the ligand precursor 2 and [Rh(acac)(CO)2] (acac = acetylacetonate). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Gadolinium DTPA‐Monoamide Complexes Incorporated into Mixed Micelles as Possible MRI Contrast Agents
Authors: Parac‐Vogt Tatjana N. , Kimpe Kristof , Laurent Sophie , Piérart Corinne , Elst Luce Vander , Muller Robert N. , Binnemans Koen
Published: June 2004

Four monoamide derivatives of Gd−DTPA with alkyl chains consisting of 12, 14, 16, or 18 carbon atoms were synthesized. The gadolinium(III) complexes with chain lengths of 14, 16 or 18 carbon atoms were efficiently incorporated into mixed micelles whereas the complex with a chain length of 12 carbon atoms was not incorporated into a micellar structure. The size distribution of the micelles was measured by photon correlation spectroscopy. The mean sizes of the micelles for all the complexes lay within a narrow range, typically between 11 and 20 nm. The NMRD curves of the gadolinium(III) DTPA‐monoamide complexes incorporated into mixed micelles display higher relaxivity values than the commercially available Gd−DTPA contrast agent. Moreover, micelles with gadolinium DTPA‐monoamide complexes showed higher relaxivities than micelles containing the corresponding gadolinium DTPA‐bis(amide) complexes, most likely because of a more efficient exchange of the coordinated water molecule. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Patient satisfaction with treatment in eating disorders: cause for complacency or concern?
Authors: Clinton David , Björck Caroline , Sohlberg Staffan , Norring Claes
Published: June 2004

The present study explored treatment satisfaction among eating disorder patients participating in a Swedish multicentre study (N = 469) who had been followed up 36 months after initial assessment. Satisfaction was measured using a questionnaire focusing on initial reception at the treatment unit, suitability of treatment, ability of staff to listen and understand, confidence in the unit and agreement on treatment goals. After 36 months, 38% of patients were ‘highly satisfied’ with treatment, while 39% were ‘satisfied’ and 23% were ‘unsatisfied’. Satisfaction was predicted by treatment interventions focusing on support and increased control of eating problems. Although unsatisfied patients were characterized by significantly higher levels of eating disorder psychopathology and psychiatric symptoms as well as more negative interpersonal profiles at follow‐up, these patients had been virtually indistinguishable from the other groups at initial assessment, with a few notable exceptions. Unsatisfied patients had previously been less prepared to change their eating habits, had higher levels of conflict with their fathers, had a lesser degree of present weight acceptance and tended to expect less from treatment interventions focusing on control of eating problems. It is concluded that, although we may be successful in engaging and satisfying patients who are predisposed to therapeutic strategies focusing on support and control of eating problems, we may be less successful with those who have a greater number of interpersonal problems and who are not as focused on their symptoms of disordered eating. Copyright © 2004 John Wiley & Sons, Ltd and Eating Disorders Association.
Eating Disorder Inventory for Children (EDI‐C): effects of age and gender in a Swedish sample
Authors: Thurfjell Barbro , Edlund Birgitta , Arinell Hans , Hägglöf Bruno , Garner David M. , Engström Ingemar
Published: June 2004

Objective

To evaluate the Swedish version of the Eating Disorder Inventory for Children (EDI‐C) from a gender and developmental perspective and to provide normative data.

Methods

Data were collected within seven cross‐sectional projects. Completed questionnaires, from 2070 boys and 2655 girls in grades 4–12, were included.

Results

The psychometric properties of EDI‐C in non‐clinical groups of girls and adolescent boys resemble those found for adolescent girls with an eating disorder. Significant differences were found between genders, grades and pre‐adolescent and adolescent groups. An increase in drive for thinness, body dissatisfaction and problems with interoceptive awareness and impulse regulation characterized the adolescent girls. Maturity fears, interpersonal distrust and social insecurity decreased during adolescence for both genders.

Conclusions

The results indicate that the EDI‐C could well be used for both boys and girls, although separate norms are recommended for pre‐adolescents and adolescents as well as for boys and girls. Copyright © 2004 John Wiley & Sons, Ltd and Eating Disorders Association.
Characteristics of the anterolateral thigh flap in a Western population and its application in head and neck reconstruction
Authors: Yu Peirong
Published: June 2004

Background.

Although the anterolateral thigh flap has been extensively used for head and neck reconstruction in Asia, reported variations of vascular anatomy seem confusing and may have contributed to the unpopularity of this flap in the United States. The purposes of this study are to classify the vascular anatomy and to assess the suitability of this flap for head and neck reconstruction in a Western population.

Methods.

Seventy‐two consecutive anterolateral thigh flaps for head and neck reconstruction was retrospectively reviewed.

Results.

The number of cutaneous perforators for the anterolateral thigh flap ranged from one to three. On the basis of their location and origin, a simple classification system is introduced to assist flap dissection. Of the 72 thighs explored, 68 flaps (94%) were raised successfully.

Conclusions.

The vascular anatomy of the flap follows predictable patterns. The anterolateral thigh flap is well suited for head and neck reconstruction in Westerners. © 2004 Wiley Periodicals, Inc. Head Neck 26: 759–769, 2004
Significant proportion of breast and/or ovarian cancer families of French Canadian descent harbor 1 of 5 BRCA1 and BRCA2 mutations
Authors: Oros Kathleen K. , Ghadirian Parviz , Greenwood Celia M.T , Perret Chantal , Shen Zhen , Paredes Yosabeth , Arcand Suzanna L. , Mes‐Masson Anne‐Marie , Narod Steven A. , Foulkes William D. , Provencher Diane , Tonin Patricia N.
Published: June 2004

In 1998, we reported that a significant proportion of breast and/or ovarian cancer families of French Canadian descent harbor specific germline mutations in BRCA1 or BRCA2 attributed to common founders. Here we report the frequency of previously described mutations (n = 7) and 13 mutations identified in French Canadian families since 1998, in a new group of families (n = 88). Four of the previously described mutations, 4446C>T, 2953delGTAinsC, 8765delAG and 6085C>T, account for 72% and 69% of mutation‐positive families in previously (n = 81) and recently ascertained groups, respectively. Only 2 of 13 recently identified mutations were found in more than 1 family: 3875delGTCT (n = 2) and 3398delAAAAG (n = 4). The 2 groups (ascertained pre‐ and post‐gene discovery) did not differ significantly when distribution of mutations based on cancer syndrome phenotype and age of diagnosis or number of breast cancer cases were compared. Five common mutations accounted for a significant proportion (84%) of all mutation‐positive families. The age of diagnosis of female breast cancer in mutation‐negative families was significantly higher than that of the mutation‐positive families (p<0.0001). The total number of cases of cancer per family was significantly lower in mutation‐negative than mutation‐positive families (p<0.001). Our results define a new mutation panel for screening BRCA1/2 mutations and the phenotype of mutation‐positive families harboring the common mutations in the French Canadian population. © 2004 Wiley‐Liss, Inc.
p150 Overexpression in gastric carcinoma: The association with p53, apoptosis and cell proliferation
Authors: Chen Gaoping , Burger Max M.
Published: June 2004

To clarify the significance of p150 expression, 102 gastric carcinomas were immunohistochemically investigated and 14 fresh samples of the cancer were analyzed with the immunoblot method. Tumor cell apoptosis was assessed by terminal deoxynucleotidyl transferase (TdT)‐mediated dUTP‐digoxigenin nick end labeling (TUNEL). Both Ki‐67 antigen and p53 expression were analyzed immunohistochemically. Eighty‐six out of 102 (85%) gastric cancers stained positively for p150. All 14 tumors analyzed by Western blotting overexpressed p150. Statistical analysis revealed a close association between p150 overexpression and the clinicopathologic parameters of gastric cancer. All well‐differentiated cancers showed high p150 expression (p < 0.005). Furthermore, high p150 expression was more frequently seen in tumors at early invasive stages (p < 0.005), in tumors without metastases (both local and distant, p < 0.005) and in early TNM stages (p < 0.005) in general. As we have found for cervix and esophagus carcinoma, when tumors progress to high malignancy and metastasis, p150 begins to regress and then breaks down. A good correlation of p150 expression, but not p53 expression, with tumor cell apoptosis could be demonstrated (p < 0.01). The Ki‐67 labeling index, i.e., the index for a proliferative marker, showed no correlation with either p150 or p53 expression. The results suggest that p150 may be a new early tumor marker for gastric carcinoma similar to that for esophagus and cervix carcinoma. © 2004 Wiley‐Liss, Inc.
Large Area Monodomain Order in Colloidal Crystals
Authors: Ruhl Tilmann , Spahn Peter , Winkler Holger , Hellmann Goetz P.
Published: June 2004

Summary: In previous papers, a novel melt process was reported for the preparation of colloidal crystals exhibiting the crystalline structure of opals. Latex spheres with a hard, crosslinked core and a grafted‐on elastomeric shell flow at elevated temperatures under uniaxial compression much like other polymer melts. However, the spheres start crystallizing at the plates of the press, whereupon the crystalline order grows, layer by layer, into the flowing melt. In this report, the domain order of opal disks thus obtained is discussed, together with the phenomena of light reflection. The pattern of light reflected from the (220) plane of the fcc lattice reveals that, during compression, this lattice is oriented macroscopically by the radial melt flow so that each radial sector of the opal disk forms a crystalline monodomain.

Film of latex spheres with colloidal crystalline order prepared by melt compression of PS/PMMAcsPEA core‐shell latex spheres.

magnified image

Film of latex spheres with colloidal crystalline order prepared by melt compression of PS/PMMAcsPEA core‐shell latex spheres.