bluuebunny/crossref_metadata_2025_split huggingface dataset:
Property‐averaging applied to determination of volume contraction in binary‐solid liquid‐fluidized beds
Authors: Escudié Renaud , Epstein Norman 
Published: May 2008

AbstractThis communication examines experimental information from the literature on the volume contraction that can occur when two monocomponent particle species that have a diameter ratio and a buoyancy‐corrected density ratio on opposite sides of unity are subjected to liquid fluidization as a binary mixture. Attempts are made to predict this volume contraction by applying monocomponent bed expansion equations using averaged properties of the binary solids. It was found that this method works better if the equations are anchored to experimental monocomponent voidages by the fractional bed volume change that they predict than if the equations are used directly. However, greater prediction accuracy can be achieved by correlation of the adjustable parameter G of the Westman, Am Ceramic Soc, 19, 127–129, (1936) equation, originally applied to binary packed beds.
Direct simulation of the buoyant rise of bubbles in infinite liquid using level set method
Authors: Yu Zhao , Fan Liang‐Shih 
Published: May 2008

AbstractIn this study, 3‐D level set method is applied to investigate the rise of gas bubbles in infinite liquid domain due to the buoyancy force. A number of typical regimes for single bubble rising are studied, including the ellipsoidal, ellipsoidal cap, spherical cap, and skirted bubbles. The bubble shape and rise velocity predicted by the simulation are compared with the graphical correlations of Grace, Trans. Inst. Chem. Eng., 51, 116–120, (1973) and Bhaga and Weber, J. Fluid Mech., 105, 61–85, (1981). Good agreement is found between the simulation results and the correlations. These simulations cover a wide range of the parameters, including Eo, Mo, and Re, and demonstrate the capability and accuracy of level set method for simulation of bubbles under various conditions with considerable deformation. Finally, simulation results for the coalescence of two bubbles are also presented.
Investigation into the hydrodynamics of gas–solid fluidized beds using particle image velocimetry coupled with digital image analysis
Authors: Laverman Jan Albert , Roghair Ivo , Annaland Martin van Sint , Kuipers Hans 
Published: May 2008

AbstractThe hydrodynamics of a freely bubbling, pseudo 2‐D fluidized bed has been investigated experimentally for different bed aspect ratios at different superficial gas velocities by using Particle Image Velocimetry (PIV) combined with Digital Image Analysis (DIA). Coupling of both non‐invasive measuring techniques allows us to obtain information on both the bubble behaviour and emulsion phase circulation patterns simultaneously. In particular, the combination of DIA with PIV allows to correct for the influence of particle raining through the roof of the bubbles on the time‐averaged emulsion phase velocity profiles.
A novel continuous reactor for catalytic reduction of NOx—fixed bed simulations
Authors: Yang Terris T. , Zhang Tianzhu , Bi Hsiaotao T. 
Published: May 2008

AbstractA novel dual‐zone fluidized bed reactor was proposed for the continuous adsorption and reduction of NOx from combustion flue gases. The adsorption and reaction behaviour of such a reactor has been simulated in a fixed bed reactor using Fe/ZSM‐5 catalyst and propylene reductant with model flue gases. Fe/ZSM‐5 exhibited acceptable activity at T = 350°C and GHSV = 5000 h−1 when O2 concentration was controlled at levels lower than 1% with a HC to NO molar ratio of about 2:1. XPS and BET surface area measurement revealed the nature of the deactivation of the catalyst. Those performance data demonstrated the feasibility of a continuous dual‐zone fluidized bed reactor for catalytic reduction of NOx under lean operating conditions.
Risk based decision‐making in plant design
Authors: Piccinini Norberto , Demichela Micaela 
Published: May 2008

AbstractAccidental events that have occurred in chemical and nuclear plants show that the application of technical regulations on its own, even when extremely detailed, does not assure that adequate safety levels are reached and, above all, maintained in time. The paper illustrates, with a simple example, how a risk analysis can be considered as an essential tool for a correct plant design, above all when dealing with major risk installations. In particular the use of the Recursive Operability Analysis is shown, in the phase of accident identification, since it allows to directly draw the logic trees, both Fault and Event Trees for the quantification phase, thus assuring the congruence of the whole analysis.
Study of horizontal sonic gas jets in gas–solid fluidized beds
Authors: Dawe Matthew , Briens Cedric , Berruti Franco 
Published: May 2008

AbstractExisting jet penetration correlations have all been developed for sub‐sonic gas jets and have been found to perform poorly when employed in sonic and supersonic regimes. In the present study, triboelectric probes were used to measure both the penetration depth and expansion angle of sonic gas jets. Experiments were conducted using nozzles of different size and geometry, different particle types, different injection gases, and different fluidization velocities. All these data were used to develop a new, general correlation to predict the penetration depth of sonic gas jets. The effects of these variables on jet expansion angle were also studied.
Hydrodynamics of a high pressure three‐phase fluidized bed subject to foaming
Authors: Rudkevitch Daniel , Macchi Arturo 
Published: May 2008

AbstractThe effects of pressure and surfactants on the phase holdups and flow regime transition velocities of gas–liquid–solid fluidized beds were investigated. The effect of pressure on the bed phase holdups is significant and more pronounced at larger gas flow rates where pressure has a greater effect on the equilibrium bubble size. The addition of a surfactant leads to an increase in the gas holdup and a lowering of the solids and liquid holdups. The presence of a surfactant with a liquid flow results in shearing of the bubbles across the gas–liquid distributor, limiting the effect of pressure. Finally, for all conditions, gas holdups in the freeboard region were greater than in the bed.
Radioactive particle tracking in a lab‐scale conical fluidized bed dryer containing pharmaceutical granule
Authors: Khanna Pankaj , Pugsley Todd , Tanfara Helen , Dumont Hubert 
Published: May 2008

AbstractRadioactive particle tracking (RPT) has been used to study the motion of the particulate phase in a bench‐scale conical fluidized bed containing dried pharmaceutical granule. RPT revealed that there is a distinct circulation pattern of the granule with particles moving upwards at high velocities near the centre of the bed and falling slowly near the walls. There was also a localized region near the centre of the bed where particles moved downward rapidly. The particle size distribution (PSD) of the granule had an appreciable impact on particle motion with a wide PSD leading to larger fluctuations in particle velocity as well as poorer granule mixing.
Drift flux modelling of CFB risers
Authors: Patience Gregory S. , Bockrath Richard E. 
Published: May 2008

AbstractSolids inventory is a critical parameter for catalytic reactors: it impacts the geometrical configuration of the reactor, compressor/blower requirements, and the overall economics of the process. Although significant advances have been made for characterizing the hydrodynamic regimes in gas–solid fluidization, empirical relationships for predicting the solids inventory in risers are largely in the developmental stages. Empirical models are either based on the slip velocity, slip factor or the Richardson–Zaki bed expansion relationship. We propose the drift flux model, commonly for gas–liquid hydrodynamic modelling. The drift flux model accounts for radial variations in the axial velocity profile and void fraction with a distribution parameter, C0, and the relative velocity between the phases with the drift velocity, U2j:$\langle \varepsilon \rangle = {{U_{\rm g} } \over {C_0 (U_{\rm g} + U_{\rm p} ) + \langle \varepsilon V_{{\rm g}j} \rangle /\langle \varepsilon \rangle }}$In high density risers, the distribution parameter varies between 1.03 and 1.12. The drift velocity is a function of the product of the particle terminal velocity and varies with solids hold‐up.
Mortality after cure of soft‐tissue sarcoma treated with conservation surgery and radiotherapy
Authors: Guadagnolo B. Ashleigh , Zagars Gunar K. , Ballo Matthew T. , Strom Sara S. , Pollock Raphael E. , Benjamin Robert S. 
Published: May 2008

AbstractBACKGROUND.The objective of the current study was to analyze the potential treatment‐related mortality in long‐term survivors of soft‐tissue sarcoma (STS) treated with radiotherapy (RT) and conservation surgery.METHODS.Between 1960 and 2000, 629 of 1089 patients treated with conservation surgery and RT for nonmetastatic STS at the University of Texas M. D. Anderson Cancer Center never developed disease recurrence. Long‐term survival and causes of death were evaluated using the person‐years method to determine the standardized mortality ratio (SMR). SMRs were calculated for death from all causes, cancer, and cardiac disease using standard U.S. data.RESULTS.The median follow‐up was 13.2 years. The 10‐year, 20‐year, and 30‐year actuarial survival rates were 88%, 69%, and 52%, respectively. The overall all‐case mortality was 1.14 (95% confidence interval [95% CI], 0.98‐1.33). The all‐cause mortality exceeded that expected for female patients with an SMR of 1.48 (95% CI, 1.15‐1.88), patients aged ≤50 years with an SMR of 1.46 (95% CI, 1.06‐1.95), and patients with nonextremity tumors with an SMR of 1.57 (95% CI, 1.15‐2.08). The overall cardiac mortality was not found to be significantly elevated. Overall cancer mortality was also not excessive, with an SMR of 1.33 (95% CI 0.99‐1.66). Subgroup analyses revealed an increased cancer mortality over the population expected for female patients aged ≤50 years with nonextremity tumors.CONCLUSIONS.In the current study, survivors of STS who were treated with conservation surgery and RT with or without chemotherapy did not appear to experience significant excess mortality compared with controls from the U.S. general population. Subgroup analyses did demonstrate that females aged ≤50 years at the time of diagnosis with nonextremity primary tumors did have higher all‐cause mortality and this increase may be due to cancer mortality. Cancer 2008. © 2008 American Cancer Society.
A Mesoporous Silica Thin Film as Uptake Host for Guest Molecules with Retarded Release Kinetics
Authors: Suh Myungkoo , Lee Ho‐Jin , Park Jin‐Young , Lee U‐Hwang , Kwon Young‐Uk , Kim Deug Joong 
Published: May 2008

AbstractUptake and release processes of various fluorescent rhodamine dyes and antitumor drugs to/from an ordered mesoporous silica film are investigated by means of UV/Vis absorption and fluorescence spectroscopies. The pores in the 160 nm‐thick silica film strongly withdraw the dyes from water, thus allowing the storage of several micrograms of guest molecules per square centimeter of film. The binding equilibrium of the dyes follows a Langmuir‐type adsorption. The dissociation constant, Kd, and the maximum binding amount to the film, ${{\rm{N}}_{{\rm{ads}}}^\infty }$, are determined by fitting the binding curves. The release kinetics of the guests from the film to a simulated body fluid (SBF) solution follows a bimodal first‐order exponential behavior. The release kinetics from the mesoporous thin film is remarkably retarded relative to that from mesoporous powders. Among all the studied dyes, rhodamine 101 is released most slowly, which implies that the release rate depends not only on the interactions between the guests and the silica surface, but also on intermolecular interactions between the guest molecules. Comparison of the release kinetics of different antitumor drugs, such as actinomycin D and mitoxantrone, into an SBF solution shows that mitoxantrone is released much slowly. This slower release is attributed to the positive molecular charge and the formation of dimers in the pores.
Asymmetric Synthesis of a Novel Conformationally Constrained D‐Lysine Analogue with a Piperidine Skeleton
Authors: Etayo Pablo , Badorrey Ramón , Díaz‐de‐Villegas María D. , Gálvez José A. 
Published: May 2008

AbstractA practical asymmetric synthesis of enantiomerically pure(2R,4R)‐1‐(tert‐butoxycarbonyl)‐4‐[2‐(methoxycarbonylamino)ethyl]pipecolic acid starting from easily accessible (R)‐2‐[(S)‐1,2‐bis(benzyloxy)ethyl]‐1‐[(S)‐1‐phenylethyl]‐4‐piperidone in around 33 % overall yield has been performed. The efficiency of the synthetic strategy developed for the synthesis of this novel conformationally constrained D‐lysine analogue relies on the high‐yielding Wadsworth–Emmons reaction of a 2‐substituted 4‐piperidone and the diastereoselective reduction of the exocyclic C=C double bond at the 4‐position of the piperidine ring.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Super‐Fluorinated Liquid Crystals: Towards the Limits of Polarity
Authors: Kirsch Peer , Binder Werner , Hahn Alexander , Jährling Kai , Lenges Marc , Lietzau Lars , Maillard David , Meyer Volker , Poetsch Eike , Ruhl Andreas , Unger Gerald , Fröhlich Roland 
Published: May 2008

AbstractHighly fluorinated liquid crystals with unprecedented polarity were obtained by introducing a tetrahydropyran moiety into their mesogenic core structure. The new materials exhibit an unusually favourable combination of mesophase properties, excellent solubility and low rotational viscosity, which renders them highly attractive for application in fast‐switching active matrix LCDs.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Functionalization of Tripodal Scaffold Molecules on Solid Support
Authors: Guarise Cristian , Zaupa Giovanni , Prins Leonard J. , Scrimin Paolo 
Published: May 2008

AbstractA versatile synthetic approach is described for the functionalization of tripodal scaffold molecules on solid support. Intrinsic problems related to the attachment of tripodal scaffolds to a resin (for example mono‐ vs. polyadducts and intramolecular cyclizations) are studied and solutions are provided. The synthetic approach relies on the use of specific protecting groups in the critical steps of the synthesis. Importantly, however, protecting groups on the scaffold molecule are never used, which significantly facilitates scaffold variation, for instance in combinatorial studies. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Simulation study of a successive interference cancellation receiver for signal monitoring on a CDMA downlink
Authors: Golanbari Michael , Ford Gary E. , Ready Michael J. 
Published: May 2008

AbstractA successive interference cancellation (SIC) algorithm is developed for the interception of signals transmitted on a CDMA forward link. The system is modelled after the IS‐95 standard but the results are also applicable to other CDMA systems such as the wideband CDMA (W‐CDMA) and IS‐2000 standards. In realistic systems, the different forward link channels are de‐orthogonalised, leading to performance degradation in conventional matched filter (CMF)‐type receivers. Simulation results indicate that the proposed SIC receiver ameliorates the detrimental effects of de‐orthogonalisation, interference and multipath, exhibiting significant gains in traffic capacity over the capacity of a CMF. The numerical simulations also show that the proposed receiver is relatively insensitive to system imperfections. The techniques developed in this paper can be used for interception, surveillance, reconnaissance or monitoring of CDMA signals; to relax the strict requirements on power control; and to improve the capacity of CDMA systems. Copyright © 2008 John Wiley & Sons, Ltd.
Impact of hip fracture, heart failure and weight loss on the risk of institutionalization of community‐dwelling patients with dementia
Authors: Harboun Marc , Dorenlot Pascale , Cohen Nadia , Steinhagen‐Thiessen Elisabeth , Ankri Joël 
Published: May 2008

AbstractObjectivesThis study sought to identify the influence of medical symptoms and diseases on the risk of nursing home placement in a prospective cohort of newly diagnosed community‐dwelling patients with dementia.Study design and settingThis study included 348 patients with dementia, consecutively diagnosed, recruited and followed at a geriatric outpatient center (mean age: 81 years, 65.5% with Alzheimer's disease, mean baseline MMSE score: 20.5, mean follow‐up: 20.5 months).ResultsAfter adjustment for factors commonly associated with institutionalization in this population, hip fracture in the 3 years preceding diagnosis, acute congestive heart failure during follow‐up and weight loss of more than 5% in any year during follow‐up were independently associated with nursing home placement.ConclusionThis study confirms the independent contribution of specific medical symptoms and diseases to earlier institutionalization of patients with dementia. These results stress the importance of better knowledge of the specific characteristics of hip fracture, weight loss and congestive heart failure in the context of dementia, to make more effective prevention possible in this patient population. Copyright © 2008 John Wiley & Sons, Ltd.
Adenine nucleotide changes in the remnant liver: An early signal for regeneration after partial hepatectomy
Authors: Crumm Sara , Cofan Montserrat , Juskeviciute Egle , Hoek Jan B. 
Published: May 2008

Abstract

Liver regeneration after partial hepatectomy (PHx) is orchestrated by multiple signals from cytokines and growth factors. We investigated whether increased energy demand on the remnant liver after PHx contributes to regenerative signals. Changes in the tissue's energy state were determined from adenine nucleotide levels. Adenosine triphosphate (ATP) levels in remnant livers decreased markedly and rapidly (to 48% of control by 30 seconds post-PHx) and remained significantly lower than those in sham-operated controls for 24 to 48 hours. The ATP decrease was not reflected in corresponding increases in adenosine diphosphate (ADP) and adenosine monophosphate (AMP), resulting in a marked decline in total adenine nucleotides (TAN). We found no evidence of mitochondrial damage or uncoupling of oxidative phosphorylation. Multiple lines of evidence indicated that the decline in TAN was not caused by increased energy demand, but by ATP release from the liver. The extent of ATP loss was identical after 30% or 70% PHx, whereas fasting or hyperglycemia, conditions that greatly alter energy demand for gluconeogenesis, affected the ATP/ADP decline but not the loss of TAN. Presurgical treatment with the α-adrenergic antagonist phentolamine completely prevented loss of TAN, although changes in ATP/ADP were still apparent. Importantly, phentolamine treatment inhibited early signaling events associated with the priming stages of liver regeneration and suppressed the expression of

c-fos

. Pretreatment with the purinergic receptor antagonist suramin also partly suppressed early regenerative signals and

c-fos

expression, but without preventing TAN loss.

Conclusion:

The rapid loss of adenine nucleotides after PHx generates early stress signals that contribute to the onset of liver regeneration. (Hepatology 2008.)
Hepatitis C virus JFH-1 strain infection in chimpanzees is associated with low pathogenicity and emergence of an adaptive mutation
Authors: Kato Takanobu , Choi Youkyung , Elmowalid Gamal , Sapp Ronda K. , Barth Heidi , Furusaka Akihiro , Mishiro Shunji , Wakita Takaji , Krawczynski Krzysztof , Liang Jake T. 
Published: May 2008

Abstract

The identification of the hepatitis C virus (HCV) strain JFH-1 enabled the successful development of infectious cell culture systems. Although this strain replicates efficiently and produces infectious virus in cell culture, the replication capacity and pathogenesis

in vivo

are still undefined. To assess the

in vivo

phenotype of the JFH-1 virus, cell culture–generated JFH-1 virus (JFH-1cc) and patient serum from which JFH-1 was isolated were inoculated into chimpanzees. Both animals became HCV RNA-positive 3 days after inoculation but showed low-level viremia and no evidence of hepatitis. HCV viremia persisted 8 and 34 weeks in JFH-1cc and patient serum–infected chimpanzees, respectively. Immunological analysis revealed that HCV-specific immune responses were similarly induced in both animals. Sequencing of HCV at various times of infection indicated more substitutions in the patient serum–inoculated chimpanzee, and the higher level of sequence variations seemed to be associated with a prolonged infection in this animal. A common mutation G838R in the NS2 region emerged early in both chimpanzees. This mutation enhances viral assembly, leading to an increase in viral production in transfected or infected cells.

Conclusion:

Our study shows that the HCV JFH-1 strain causes attenuated infection and low pathogenicity in chimpanzees and is capable of adapting

in vivo

with a unique mutation conferring an enhanced replicative phenotype. (Hepatology 2008.)
Evaluation of circulating endothelial cells, VEGF and VEGFR2 serum levels in patients with chronic myeloproliferative diseases
Authors: Alonci A , Allegra A , Bellomo G , Penna G , D'Angelo A , Quartarone E , Musolino C 
Published: May 2008

AbstractAuthors evaluated some markers of angiogenetic activity in patients with chronic myeloproliferative diseases (CMDs). In this study by using a cytofluorimetric analysis we evaluated circulating endothelial progenitor cells (EPCs) in patients with chronic myeloproliferative disease. Moreover, in the same group of subjects, we evaluated serum levels of vascular endothelial growth factor (VEGF) and vascular endothelial growth factor receptor‐2 (VEGFR2). In our patients, we have found an increase in the number of endothelial progenitor cells in primary myelofibrosis (PMF) and polycythaemia vera (PV) patients, while an increase of circulating endothelial cells (CECs) was found in all patients with CMD. Moreover, we found higher serum levels of VEGF with respect to control subjects in every group of patients with CMD, and a not significant reduction of VEGFR2 levels in essential thrombocythaemia (ET) patients. A correlation was also found in PV patients between VEGF levels and erythrocyte number and in PMF subjects with the count of white cells. Our data suggest that some markers of angiogenesis are activated in CMD patients and angiogenesis may have a role in the pathophysiology of chronic myeloproliferative disorders. Copyright © 2008 John Wiley & Sons, Ltd.