bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Sparging Gas Properties and Substrate Size on Enzymatic Hydrolysis of Waste Paper in an Ultrasonic External Loop Airlift
Authors: Li C. , Matsunaga T. , Seki K. , Yoshimoto M. , Furumoto K. , Fukunaga K. , Nakao K. 
Published: August 2006

AbstractOffice paper shredded into various sizes was used as a model substrate for waste paper in the present work, aimed at developing an efficient utilization for waste cellulosics. The enzymatic hydrolysis of the office paper was carried out in an external loop airlift bubble column reactor equipped with an ultrasonic horn system, by sparging with water‐saturated or unsaturated gas. The enhanced hydrolysis was characterized by a two‐stage time course when either water‐unsaturated air or nitrogen was bubbled into the reaction suspension in the airlift reactor, without ultrasonic irradiation. In contrast, a much lower enhanced effect was observed when either saturated air or nitrogen was employed. The total sugar productivity with sparging by either saturated air or nitrogen was lower than in the case of sparging by unsaturated gas. This was ascribed to a shear stress acting on the surface of the paper in the gas sparging section in the riser. The critical superficial gas velocity for complete circulation of the substrate was reduced as its size was decreased. The smaller paper size for sparging with unsaturated air resulted in a more enhanced hydrolysis with a more remarkable two‐stage time course. In the case of sparging with saturated air, the continuous ultrasonic irradiation was effective for enhancing the enzymatic hydrolysis. The time courses of the glucose and total sugar concentrations were successfully analyzed and simulated, based on the kinetic model proposed previously. The variation in the paper size, sparging gas humidity and ultrasonic irradiation exerted an effect on the apparent rate constant and ultimate total sugar concentration, but had no effect on the apparent Michaelis, competitive inhibition and equilibrium constants.
Investigations on the Stability of the Flow Characteristics in a Bubble Column
Authors: Lucas D. , Krepper E. , Prasser H.‐M. , Manera A. 
Published: August 2006

AbstractThe role of the lift force in the stability of the homogeneous flow regime in a bubble column is investigated. Instabilities caused by the lift force may be one important reason for the transition from a homogeneous to a heterogeneous bubble column. The lift force acts on rising bubbles in a lateral direction when gradients of the liquid velocity are present. Such gradients may result from circulation cells in the bubble column as well as from local disturbances. Depending on the sign of the lift force, such local disturbances in a homogeneous flow may be damped or enhanced. The corresponding feedback mechanism was analyzed by means of linear stability analyses. As a result, criteria for stability were obtained for mono‐dispersed flow, for a flow with two bubble size groups, and, finally, with some additional approximations also for the case of N bubble size groups or a given bubble size distribution. In a next step, the effects were investigated by CFD calculations. The obtained criteria for stability fit well with the observed effects in CFD simulations. Recently, two different groups confirmed the stability criteria experimentally.
Effect of Liquid Velocity on Axial Mixing in Gas‐Liquid Dispersions: A CFD Simulation
Authors: Roy S. , Joshi J. B. 
Published: August 2006

AbstractA CFD analysis has been carried out to elucidate the characteristic features of axial mixing in gas‐liquid dispersed upflow when the flow changes between two extremes: from bubble column, with very low/no liquid velocity, to pipe flow with very high liquid velocity. The CFD model was validated by simulating flow both in multiphase and in single phase. An agreement was observed between the predictions and the experimental data available in the published literature. The validated CFD model has been extended for the simulation of the axial dispersion coefficient for both multiphase and single phase. CFD predictions of the axial dispersion coefficient show good agreement with experimental values published in the literature. A systematic numerical study was done by varying the superficial liquid velocity, from a very low value to a very high value, to understand its effect on axial dispersion.
Detailed 3D Modeling of Mass Transfer Processes in Two‐Phase Flows with Dynamic Interfaces
Authors: Darmana D. , Deen N. G. , Kuipers J. A. M. 
Published: August 2006

AbstractA model is presented which allows a priori computation of mass transfer coefficients for bubbles (droplets) rising in quiescent Newtonian fluids. The proposed model is based on the front tracking technique and explicitly accounts for the bubble‐liquid mass transfer process. The dissolved species concentration in the liquid phase is computed from a species conservation equation while the value of the concentration at the interface is imposed via an immersed boundary technique. Simulations are carried out to demonstrate the capabilities of the model to predict bubble shape, flow field as well as transport of a species from the bubble to the liquid phase.
Correction of the Penetration Theory applied to the Prediction of kLa in a Bubble Column with Organic Liquids
Authors: Nedeltchev S. , Jordan U. , Schumpe A. 
Published: August 2006

AbstractWhen Higbie's penetration theory is applied to calculate kL‐values for ellipsoidal rather than spherical bubbles, some correction factor needs to be introduced. In a recent paper, such a correction factor (less than unity) was derived for the homogeneous flow regime, based on kLa‐data measured in 1‐butanol, toluene, ethanol, and tap water: fc = 0.211 Eo0.63. In the present work, the validity of this approach is further tested on kLa‐data published for ethylbenzene, xylene, tetralin, anilin, nitrobenzene, 1,2‐dichloroethane, 1,4‐dioxane, 2‐propanol, benzene, ligroin, and ethyl acetate. The full data set involving 79 experimental kLa‐values at homogeneous flow in 14 organic liquids and tap water, is correlated with a 8.7 % mean error in the following modified form: fc = 0.185 Eo0.737.
Flow Regime Identification in a Bubble Column Based on Both Statistical and Chaotic Parameters Applied to Computed Tomography Data
Authors: Nedeltchev S. , Shaikh A. , Al‐Dahhan M. 
Published: August 2006

AbstractThe Kolmogorov entropy (KE) algorithm was applied successfully to single source γ‐ray Computed Tomography (CT) data measured in a 0.162 m ID bubble column equipped with a perforated plate distributor (163 holes · ∅︁ 1.32 mm). Dried air was used as the gas phase and Therminol LT (ρL = 886 kg m–3, μL = 0.88 · 10–3 Pa  s, σ = 17 · 10–3 N m–1) was used as a liquid phase. Three different pressures, P, of 0.1, 0.4, and 1.0 MPa were examined. At each pressure the superficial gas velocity, uG, was increased stepwise by steps of 0.01 m s–1 up to 0.2 m s–1. The average absolute deviation (AAD) was also used as a robust statistical criterion for regime transition. At all three pressures, based on the sudden changes in both the AAD and KE values, the boundaries of the following five regimes were identified: dispersed bubble regime, first and second transition regimes, coalesced bubble regime consisting of four regions (called 4‐region flow), and coalesced bubble regime consisting of three regions (called 3‐region flow). The existence of these regimes has already been documented. As the pressure increases, the transition velocity between the dispersed bubble and first transition regimes and the transition velocity between coalesced bubble (4‐region flow) and coalesced bubble (3‐region flow) regimes shift to higher uG values. On the other hand, at P = 0.4 MPa the second transition regime starts earlier. In addition, at P = 1 MPa the transition to coalesced bubble (4‐region flow) is delayed.
Hydrodynamics and Mixer‐Induced Bubble Formation in Micro Bubble Columns with Single and Multiple‐Channels
Authors: Haverkamp V. , Hessel V. , Löwe H. , Menges G. , Warnier M. J. F. , Rebrov E. V. , de Croon M. H. J. M. , Schouten J. C. , Liauw M. A. 
Published: August 2006

AbstractA hydrodynamic characterization of an industrially used gas‐liquid contacting microchannel device is discussed, viz. the micro bubble column of IMM. Furthermore, similar characterization of a gas‐liquid flow microchip of TU/e, with two tailored mixer designs, is used to solve fundamental issues on hydrodynamics, and therefore, to achieve further design and operating optimization of that chip and the IMM device. Flow pattern maps are presented in a dimensionless fashion for further predictions on new fluidic systems for optimum single‐channel multiphase operation. Bubble formation was investigated in the two types of mixers and pinch‐off and hydrodynamic decay mechanisms are observed. The impact of these mechanisms on bubble size, bubble size distributions, and on the corresponding flow patterns, i.e., the type of mixer design, can be decisive for the flow pattern map and thus, may be used to alter flow pattern maps. The bubble sizes and their distribution were improved for the tailored designs, i.e., smaller and more regular bubbles were generated. Finally, the impact of multi‐channel distribution for gas and liquid flow is demonstrated. Intermediate flow patterns such as slug‐annular flow, also found for single‐phase operation, and the simultaneous coexistence of flow regimes are presented, with the latter providing evidence of flow maldistribution.
The Effect of Nozzle Shape on Bubble Formation from a Downward Nozzle
Authors: Tsuge H. , Mitsudani M. , Tezuka Y. 
Published: August 2006

AbstractA lot of research has been conducted on the gas injection methods; especially bubble formation from the upward orifice or nozzle, whereas few studies on bubble formation from the downward nozzle have been reported. In this study, the effects of both nozzle shape and diameter on the bubble formation mechanism from the vertically downward nozzle were investigated. The theoretical results obtained by applying the revised two‐stage spherical bubble formation model for the downward nozzle was compared with the experimental results for small metal downward nozzles. The bubble formation mechanism and the bubble size were influenced by the edge angle and diameter of the nozzle, respectively, and the gas flow rate.
Synthesis, Structure, and in vitro Antitumor Activity of Some Glycoside Derivatives of Ferrocenyl‐Chalcones and Ferrocenyl‐Pyrazolines
Authors: Zsoldos‐Mády Virág , Csámpai Antal , Szabó Rita , Mészáros‐Alapi Erika , Pásztor Judit , Hudecz Ferenc , Sohár Pál 
Published: August 2006

AbstractSome new glycosides of 3‐ferrocenyl‐1‐(4′‐hydroxyphenyl)‐prop‐2‐en‐1‐one were prepared and transformed into the corresponding pyrazoline and pyrazole derivatives. Using methyl‐hydrazine, formation of regioisomers was observed. DDQ was found to be a mild and efficient reagent for the pyrazoline‐pyrazole dehydroaromatization process. The structure of the new compounds was proved by IR and NMR spectroscopy. The in vitro antitumor activity of the substances was investigated against human leukemia (HL‐60) cells by the MTT method. Among these new compounds some chalcone derivatives (3 a, 3 b, 5 a, and 5 b) showed attractive in vitro antitumor effects on human leukemia cells. These molecules contained ferrocenyl moieties and a p‐hydroxy‐phenolic ring or a size‐independent apolar substitution of that.
6‐Alkylthio‐4‐[1‐(2,6‐difluorophenyl)alkyl]‐1H‐[1,3,5]triazin‐2‐ones (ADATs): Novel Regulators of Cell Differentiation and Proliferation
Authors: Sbardella Gianluca , Bartolini Sara , Castellano Sabrina , Artico Marino , Paesano Nicola , Rotili Dante , Spadafora Corrado , Mai Antonello 
Published: August 2006

AbstractNovel triazine analogues of 5‐alkyl‐2‐alkylthio‐6‐[1‐(2,6‐difluorophenyl)alkyl]‐3,4‐dihydropyrimidin‐4(3H)‐ones (F2‐DABOs), previously described by us as nonnucleoside HIV‐1 reverse transcriptase inhibitors (NNRTIs), were tested for their antiproliferative and cytodifferentiating activity on the A‐375 human melanoma cell line. Most of the tested derivatives were effective in decreasing cell proliferation, facilitating morphological differentiation, and reprogramming gene expression. All these effects were reversible upon withdrawal of RT inhibitors. Among the compounds tested, 3 f showed the highest antiproliferative effect, whereas compound 6 c, although not affecting cell proliferation, is endowed with a strong cytodifferentiating effect, which is probably related to a marked upregulation of the e‐cad gene. These results support the potential of NNRTIs as valuable antitumor agents.
Novel approaches in the treatment of systemic mastocytosis
Authors: Quintas‐Cardama Alfonso , Aribi Ahmed , Cortes Jorge , Giles Francis J. , Kantarjian Hagop , Verstovsek Srdan 
Published: August 2006

AbstractIn the absence of curative options, therapy for aggressive forms of systemic mastocytosis (SM) has relied in the use of cytoreductive agents, mainly interferon‐α (IFN‐α) and cladribine. However, responses are transient and only occur in a subset of patients. Gain‐of‐function mutations at codon 816 of the KIT protooncogene lead to constitutively active Kit receptor molecules, which are central to the pathogenesis of SM. Recent advances in the understanding of the molecular underpinnings of SM have led to the development of small molecules targeting mutant Kit tyrosine kinase isoforms that significantly have widened the range of therapeutic options for patients with SM. Some of these promising agents, such as dasatinib, AMN107, and PKC412, currently are under investigation in clinical trials whereas, others are at different stages of preclinical development. In addition, monoclonal antibodies directed to neoplastic mast cell‐restricted surface antigens constitute a viable option for the treatment of SM that warrants further investigation. Cancer 2006. © 2006 American Cancer Society.
Noninvasive imaging for evaluation of the systemic delivery of capsid‐modified adenoviruses in an orthotopic model of advanced lung cancer
Authors: Sarkioja Merja , Kanerva Anna , Salo Jarmo , Kangasniemi Lotta , Eriksson Minna , Raki Mari , Ranki Tuuli , Hakkarainen Tanja , Hemminki Akseli 
Published: August 2006

AbstractBACKGROUND.Variable expression of the coxsackie and adenovirus receptor (CAR) has limited gene transfer efficacy to many types of tumors. Consequently, tropism‐modified adenoviruses have been developed for enhanced infectivity. To the authors' knowledge, targeting approaches for nonsmall cell lung cancer (NSCLC) have not been comprehensively evaluated. The current hypothesis was that modified adenoviruses could be used for increasing gene transfer to and killing of NSCLC cells in vitro and in vivo.METHODS.Ten NSCLC cell lines were analyzed to represent the different NSCLC histologies. Because clinical tumors may differ from established cell lines, 6 clinical specimens fresh from patients were analyzed. For in vivo studies, a novel orthotopic murine model of advanced lung cancer was developed. Because tumor response is difficult to quantitate in orthotopic models, noninvasive imaging of green fluorescent protein (GFP) was utilized as a surrogate for tumor size measurements.RESULTS.Adenoviruses whose capsids were modified with RGD‐4C, the serotype 3 knob, or polylysine displayed increased gene transfer to NSCLC cell lines and clinical samples in comparison to serotype 5 viruses. Conditionally replicating oncolytic adenoviruses (CRAds) with the same modifications showed enhanced therapeutic efficiency in vitro and in vivo. The median survival of mice treated with Ad5.pK7‐Δ24 or Ad5‐Δ24RGD increased 37% (P<.01). GFP imaging allowed noninvasive individualized detection of response and recurrence.CONCLUSIONS.Targeting of adenovirus to heterologous receptors can improve killing of NSCLC cells. Utilization of clinical samples and an orthotopic model of advanced lung cancer may provide clinically relevant translational data. Cancer 2006. © 2006 American Cancer Society.
1,4‐Diazabicyclo[2.2.2]octane (DABCO) as an Efficient Reagent for the Synthesis of Isoxazole Derivatives from Primary Nitro Compounds and Dipolarophiles: The Role of the Base
Authors: Cecchi Luca , De Sarlo Francesco , Machetti Fabrizio 
Published: August 2006

AbstractThe dehydration of primary nitro compounds can be performed by bases in the presence of dipolarophiles. The reactivity of several tertiary amines or azaheteroaromatic compounds containing one or two basic centres is shown to be related to the ability of the protonated base to establish H‐bonded ion pairs with the adduct that is formed from the nitronate and the dipolarophile in chloroform. Among the organic bases examined, caged tertiary diamine 1,4‐diazabicyclo[2.2.2]octane (DABCO) gave the best results. The reaction is applicable to activated nitro compounds and to phenylnitromethane and affords isoxazoline derivatives in higher yields compared with those of other methods. The reaction, however, is not compatible with nitroalkanes. The proposed mechanism of the reaction is based on the collapse of the H‐bonded ion pair. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
A Formal Total Synthesis of Virantmycin: A Modular Approach towards Tetrahydroquinoline Natural Products
Authors: Keck Daniel , Vanderheiden Sylvia , Bräse Stefan 
Published: August 2006

AbstractA synthesis of an advanced intermediate towards the racemic form of the antiviral agent virantmycin has been developed featuring an intramolecular aza‐xylylene Diels–Alder reaction. The required arylthiocarbamate has been constructed using an efficient oxidative cyclization strategy. A novel synthetic approach to chlorine‐substituted allylic alcohols using an unprecedented palladium‐catalyzed cross‐coupling reaction of α,β‐unsaturated ketones and protected propargylic alcohols is reported.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
RGD peptide‐conjugated poly(dimethylsiloxane) promotes adhesion, proliferation, and collagen secretion of human fibroblasts
Authors: Li Bin , Chen Jianxin , Wang James H.‐C. 
Published: August 2006

AbstractA novel technique for conjugating Arg‐Gly‐Asp (RGD) peptides to poly(dimethylsiloxane) (PDMS) surfaces as well as its application to cell culture is presented in this paper. This technique performs RGD conjugation to PDMS through photochemical immobilization of functional NHS groups to PDMS surface followed with linking RGD peptide to the surface via coupling reaction with NHS. A bifunctional photolinker, N‐sulfosuccinimidyl‐6‐(4′‐azido‐2′‐nitrophenylamino)hexanoate (sulfo‐SANPAH), was used to conjugate RGD peptide to the surface. Compared to existing methods for peptide conjugation to PDMS, this technique is convenient, efficient, and free of organic contamination to PDMS surfaces. It can also be used to conjugate other peptides or proteins to most polymeric materials. In addition, cell culture studies showed that the RGD‐conjugated PDMS surfaces promoted the adhesion, proliferation, and collagen production of human skin fibroblasts (HSFs). Finally, the RGD‐conjugated PDMS surfaces are resistant to autoclaving and UV irradiation, which enables them to be repeatedly used in cell culture studies. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Gradient substrate assembly for quantifying cellular response to biomaterials
Authors: Mei Ying , Elliott John T. , Smith Jack R. , Langenbach Kurt J. , Wu Tao , Xu Chang , Beers Kathryn L. , Amis Eric J. , Henderson Lori 
Published: August 2006

AbstractUsing quantitative fluorescence microscopy in conjunction with a method of gradient substrate assembly established in their group, the authors were able to introduce and measure reproducible changes in cellular morphology and cell density by manipulating polymer grafting density. The mechanism behind this change in cellular behavior was explained by a semiempirical, geometric model that describes the effect of the spatial distribution of the polymer on protein attachment. A 10‐fold increase in graft density of poly(2‐hydroxyethyl methacrylate) [PHEMA] along the surface of a gradient sample, preexposed to bovine fibronectin, caused a change in the size of fibroblasts on the surface (i.e., cell spreading) from (1238 ± 704) to (377 ± 216) μm2. The results were in quantitative agreement with those obtained on three separate gradient samples. Both cellular response and fibronectin adsorption (as measured via ellipsometry) were found to vary sigmoidally with graft density of PHEMA, demonstrating the high degree of correlation between the two phenomena. A simple, rigid‐disk model accounting for the surface coverage of PHEMA was able to predict the amount of adsorbed fibronectin with a correlation coefficient of 0.97. Maximal cell adhesion and cell spreading were found to occur at fibronectin surface densities of 50 and 100 ng/cm2, respectively. The results demonstrate the role of gradient substrate assembly as a method for quantifying the relationship between protein and cellular response to technologically relevant polymeric materials. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Cultivation of MC3T3‐E1 cells on a newly developed material (Sponceram®) using a rotating bed system bioreactor
Authors: Suck Kirstin , Behr Larissa , Fischer Marcel , Hoffmeister Hans , van Griensven Martijn , Stahl Frank , Scheper Thomas , Kasper Cornelia 
Published: August 2006

AbstractThe influence of a 3D macroporous scaffold (Sponceram®) on the differentiation process into bone cells was investigated under static conditions in cell culture dishes. Furthermore, cultivations were performed using a new bioreactor system in the presence or absence of bone morphogenetic protein 2 (BMP‐2). Preosteoblastic MC3T3‐E1 cells were first cultured on Sponceram scaffolds in 96‐well dishes using standard medium, differentiation medium and BMP‐2 medium. Cell proliferation showed a similar course for all conditions used. Alkaline phosphatase (AP) activity resulted in a maximum at day 5 in the presence of BMP‐2. Two bioreactor cultivations were performed in a BIOSTAT® Bplus RBS (rotating bed system) 500 on Sponceram carrier discs. One cultivation was performed using standard medium. The second one was used with the same medium with BMP‐2 substituted. Significant calcification of the extracellular matrix in the presence of BMP‐2 occurred but even in the absence of BMP‐2 mineralization was observed. mRNA expression of collagen I, osteocalcin and bone sialoprotein was detected after both reactor cultivations. This study demonstrates that macroporous Sponceram is suitable for the cultivation and differentiation of MC3T3‐E1 cells into the osteoblastic phenotype. The results of the bioreactor cultivation revealed that the scaffold promoted the differentiation process even in the absence of BMP‐2. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2007
MRI of the kidney and urinary tract
Authors: Israel Gary M. 
Published: August 2006

AbstractMRI of the kidney and urinary tract has evolved with advancements in MR technology combined with further radiologic experience. A combination of simple pulse sequences and the use of gadolinium (Gd) allow a comprehensive evaluation of the genitourinary system and facilitate the detection and accurate characterization of renal and urinary tract masses. In this review an MRI technique used to evaluate the kidneys and urinary tract is presented with an emphasis on the characterization of renal masses. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.