bluuebunny/crossref_metadata_2025 huggingface dataset:
Accuracy of the Diagnosis of Fibromyalgia by Family Physicians: Is the Pendulum Shifting?
Authors: SHLEYFER ELENA , JOTKOWITZ ALAN , KARMON ANATTE , NEVZOROV ROMAN , COHEN HAGIT , BUSKILA DAN
Published: December 2008

Objective.

We evaluated the accuracy of diagnosis of fibromyalgia (FM) by family physicians.

Methods.

We performed a retrospective cohort analysis of 646 consecutive patients newly referred to the outpatient rheumatology clinic of Soroka University Medical Center from January 1, 2005, until December 31, 2007. The kappa statistic was used to measure agreement between family-physician and rheumatologist diagnoses for FM in the total patient cohort as well as in groups stratified by ethnicity. Sensitivity and specificity of family-physician diagnosis of FM were calculated using rheumatologist diagnosis as the gold standard. There were no exclusion criteria.

Results.

During the time period of the study, 646 new patients were seen in the rheumatology clinic. Of 196 patients referred with an initial diagnosis of FM, the consultant rheumatologist confirmed this diagnosis in 71% of cases. The overall kappa for FM diagnosis between family physicians and rheumatologists was 0.70 (p < 0.001), indicating a good level of agreement. Agreement was substantially lower among Bedouin patients (κ = 0.35, p = 0.003). All other patients in our study were Jewish Israelis. Using rheumatologist diagnosis as the gold standard, overall sensitivity and specificity of FM diagnosis by family physicians were 87.4% and 88.3%, respectively.

Conclusion.

Family physicians in our region are able to accurately diagnose FM. Future studies might focus on evaluating the factors and biases accounting for differences in level of diagnostic accuracy for FM among various ethnic groups.
The HLA-B27 Transgenic Rat, a Model of Spondyloarthritis, Has Decreased Bone Mineral Density and Increased RANKL to Osteoprotegerin mRNA Ratio
Authors: RAUNER MARTINA , STUPPHANN DANIELA , HAAS MARTIN , FERT INGRID , GLATIGNY SIMON , SIPOS WOLFGANG , BREBAN MAXIME , PIETSCHMANN PETER
Published: December 2008

Objective.

Bone metabolism in spondyloarthritis (SpA) is not well elucidated. We investigated alterations in bone in the HLA-B27 transgenic rat, a model of SpA.

Methods.

Femur, tibia, and lumbar vertebral bodies of disease-prone HLA-B27 transgenic, healthy HLA-B7 transgenic, and nontransgenic control rats were used for bone histomorphometric and dual energy x-ray absorptiometry (DEXA) analysis. Serum levels of type I collagen C-telopeptides (CTX), N-terminal propeptide of type I procollagen (P1NP), and osteocalcin, as well as receptor activator of nuclear factor-κ B ligand (RANKL) and osteoprotegerin (OPG), were measured. RNA was isolated from the bone tissue of the femura to analyze gene expression of RANKL, OPG, and osteocalcin.

Results.

Histomorphometric analysis indicated a significant decrease in bone volume as well as trabecular number and thickness in the HLA-B27 rats. Trabecular separation was increased. Numbers of osteoblasts, osteoclasts, and osteoid volume were not altered significantly. The decrease in bone mineral density was confirmed using DEXA. Levels of RANKL mRNA were significantly increased in the bone tissue of HLA-B27 transgenic rats, resulting in an increased RANKL to OPG ratio. Osteocalcin mRNA expression was also significantly elevated in bone of HLA-B27 rats. Serum levels of CTX, RANKL, OPG, P1NP, and osteocalcin did not differ significantly.

Conclusion.

Our data indicate that, similarly to SpA in humans, HLA-B27 transgenic rats show a reduced bone mass, and suggest an involvement of the RANKL/OPG system in the mechanism of bone loss in this disease. This model may be adequate to study osteoporosis in SpA.
The Challenge of Collaboration: Organizational Structure and Professional Identity
Authors: Koester Jolene , Hellenbrand Harry , Piper Terry D.
Published: December 2008

The learning encompassed by a baccalaureate degree is not a collection of discrete parts linked to specific classes but rather the cumulative consequence and judgments for all aspects of the learning environment…. Learning takes place from the curriculum and classroom but also through personal development, cocurricular activities, and community activities.

—from the president's 2003 convocation address
Antibacterial electrospun chitosan/poly(vinyl alcohol) nanofibers containing silver nitrate and titanium dioxide
Authors: Son Bokgi , Yeom Bong‐Yeol , Song Sang Hun , Lee Chang‐Soo , Hwang Taek Sung
Published: December 2008

Chitosan/poly(vinyl alcohol) (PVA) nanofibers with antibacterial activity were prepared by the electrospinning of a chitosan/PVA solution with a small amount of silver nitrate (AgNO3) and titanium dioxide (TiO2). Nanofibers with diameters of 270–360 nm were obtained. The yield of low‐viscosity chitosan (LCS)/PVA nanofibers was higher than that of high‐viscosity chitosan (HCS)/PVA, and the water content of the HCS/PVA nanofibers and the LCS/PVA nanofibers were 430 and 390%, respectively. The nanofibers developed in this study exhibited antibacterial activities of 99 and 98% against Staphylococcus aureus and Escherichia coli, respectively. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Preparation, characterization, and adsorption properties of chitosan microspheres crosslinked by formaldehyde for copper (II) from aqueous solution
Authors: Du Wen‐Li , Niu Shan‐Shan , Xu Zi‐Rong , Xu Ying‐Lei
Published: December 2008

The chitosan microspheres crosslinked by formaldehyde were prepared by spray drying method and used as an adsorbent for copper (II) from aqueous solution. A batch adsorption system was applied to study the adsorption of copper (II) from aqueous solution by chitosan microspheres. The maximum adsorption capacity of the chitosan microspheres for copper (II) was 144.928 mg/g at pH 6.0. Langmuir adsorption model was found to be applicable in interpreting the adsorption process. To elucidate the adsorption mechanism, the chitosan microspheres before and after copper (II) adsorption were further characterized by Fourier transform infrared spectra, zeta potential analysis, and scanning electron microscope. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Diffusion of mineral oil in styrene‐butadiene polymer films
Authors: Fouchet Bernard
Published: December 2008

Mineral oil diffusion in styrene‐butadiene polymer films was investigated with a simple gravimetric sorption method. Over the selected range of temperatures and film thicknesses for which sorption tests were performed, the diffusion process is described in terms of Fick's third law. Polymer dissolution was found to compete with the diffusion process especially at high temperature. Possible interference due to dissolution on data generated using a gravimetric method, resulted in an estimation of apparent activation energy using diffusion coefficient set calculated with Crank's half‐time relationship. The mineral oil diffusion activation energy was found to be relatively high compared with those of hydrocarbons diffusing in natural and synthesized rubbers or crosslinked polybutadiene as reported in the literature. The influence of polymer Tg, crosslinking density, and polarity on mineral oil ability to penetrate polymer film was evaluated in terms of percent weight increase over time. Maximum absorption after 60‐min sorption time linearly correlates with mineral oil absorption rate for polymers prepared with different structures. This linear relationship suggests that diffusion of solvent in styrene‐butadiene polymers reveals the macroscopic composition and structural polymer modification rather than local changes. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
High‐purity nano particles ZnS production by a simple coupling reaction process of biological reduction and chemical precipitation mediated with EDTA
Authors: Xin Baoping , Huang Qun , Chen Shi , Tang Xuemei
Published: December 2008

High‐purity nanoparticles ZnS has been successfully synthesized using a simple coupling reaction process of biological reduction and chemical precipitation mediated with EDTA referred to as the CRBRCP‐EDTA process. This research investigated the optimum conditions of the transformation of SO into S2− by SRB, and the production of ZnS in the CRBRCP‐EDTA process. The results showed that the molar ratio of Zn2+ to EDTA = 1:1 was crucial for SRB growth and ZnS synthesis. At the ration(Zn2+)/n(EDTA) = 1:1, lower Zn2+ concentration enhanced both the growth of SRB and the reduction of SO, leading to higher ZnS production. Although increase in Na2SO4 concentration resulted in decrease in both SRB growth and SO reduction, it improved the S2− and ZnS production. Under the optimum conditions (0.05 mol L−1 ZnCl2, 0.05 mol L−1 EDTA, and 0.1 mol L−1 Na2SO4), the synthesized ZnS was characterized by X‐ray diffraction (XRD), X‐ray energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The analysis showed that the obtained ZnS were high‐purity and well‐distributed solid spheres with diameters of about 15 nm for primary particles and around 400 nm for secondary particles. When polyacrylamide (PAM) was incorporated in the CRBRCP‐EDTA process, the secondary particle's diameters were reduced to less than 100 nm. The photoluminescence (PL) spectra of produced ZnS centered at 396 nm, the spectrum with PAM added showed the gradual increase in absorption and stronger intensity in PL property. The present simple, low‐cost, and safe method may be extended to prepare other metal‐sulfide nanocomposites.
Ice Crystal Size Changes During Ripening in Freeze Concentration
Authors: Smith Carol E. , Schwartzberg Henry G.
Published: December 2008

Crystal sizes were measured photographically versus elapsed time for non‐uniform ice crystal populations mixed at equilibrium temperatures with sugar solutions. The mass of ice did not change, but crystals smaller than a “neutral diameter,” Dn, tended to melt because of their excess surface energy. This subcooled the solution with respect to larger crystals, which consequently grew. This process, “ripening,” which slowly increases mean crystal sizes and Dn is used to produce ice crystals large enough to be cleanly separated from freeze concentrated solutions. “Sequential analysis” was used to determine Dn and follow changes in the diameters, Di, of fractions of the ice crystal populations. Rates of change in Di for both growth and melting were roughly proportional to (I/Dn ‐ 1/Di. Overall mass‐transfer coefficients were not markedly different for growth and melting, and decreased from roughly 2 mm/s to roughly 0.5 mm/s as sugar concentration increased 10% to 42%. In 10% sucrose solutions, mass‐transfer coefficients decreased from roughly 2 mm/s to roughly 1 mm/s when gelatin was added at levels which increased from 0% to 0.5%. Ripening in freeze concentrated liquid foods apparently can be accelerated by manipulating initial crystal size distributions and temporarily removing high molecular weight components.
Fouling of Heat Transfer Surfaces Related to β‐Lactoglobulin Denaturation During Heat Processing of Milk
Authors: Lalande Marc , Tissier Jean‐Pierre
Published: December 2008

Denaturation of β‐lactoglobulin during heating of milk in a plate heat exchanger has been investigated as an important factor in fouling the heat transfer surface. Using, on one hand, data on chemical composition of deposits obtained from biochemical analysis technics and, on the other hand, kinetic data of β‐Iactoglobulin denaturation, the distribution profile of deposits along the surface and the experimental fouling curves can be adequately predicted.
Hyperexpression of Escherichia coli Xylose Isomerase
Authors: Batt Carl A. , O'Neill Elizabeth , Novak Steven R. , Ko Judy , Sinskey Anthony
Published: December 2008

The xylose isomerase (xylA) structural gene was cloned under the control of the tac promoter and expressed in a xyl+ E. coli strain. Xylose isomerase accounted for approximately 28% of the total cell protein when this tac‐xylA fusion was induced with isopropylthio β‐D‐galactopyranoside. Hyperexpression of the xylA gene inhibited xylose utilization. E. coli carrying this tac‐xylA fusion was encapsulated in calcium‐alginate beads and used to isomerase xylose in a column reactor. Conversion of xylose to xylulose was 3–4% with a residence time in the column of 2 minutes and a maximum of 12% upon recycling.
A Generalized Model for Swelling‐Controlled Release Systems
Authors: Singh S. K. , Fan L. T.
Published: December 2008

A generalized model has been developed for simultaneous transport of an active agent and an organic penetrant in a planar glassy polymer matrix. The active agent diffuses out of the matrix undergoing macromolecular chain relaxation and volume expansion due to absorption of the organic penetrant from the environment into the matrix. The swelling behavior of the polymer is characterized by a stress‐induced drift velocity term “v” corresponding to the so‐called case‐II velocity. The change of volume due to the relaxation phenomenon is assumed instantaneous. The model incorporates convective transport of the two species induced by volume expansion and by stress gradient. The proposed phenomenological model reduces to a number of special cases depending on polymer‐penetrant system behavior.
An Analysis of Residence Time Distribution Patterns in A Twin Screw Cooking Extruder
Authors: Altomare Robert E. , Ghossi Parviz
Published: December 2008

The influence of a co‐rotating twin screw extruder's controlling variables on its residence time distribution (RTD) patterns were measured and analyzed. Variables studied included: screw profile, throughput, screw speed, moisture content and die diameter. Throughput, screw speed and screw profile had strong influence on the mean residence time. Water content, die size and temperature did not.

A combination plug flow—perfect mixing model was shown to adequately describe the dimensionless RTD data.
Predicting Temperature vs Time Behavior During the Freezing and Thawing of Rectangular Foods
Authors: Reinick Amelia Rubiolo De , Schwartzberg Henry
Published: December 2008

Based on the effective heat capacity characteristics of biological materials during freezing we have derived a short‐cut equation for predicting their temperature vs time behavior during freezing and thawing. The equation can be used in the low Biot number range for rectangular bodies with similar or dissimilar heat‐transfer coefficients at their different surfaces. It has been experimentally and numerically tested for rectangular blocks of chopped beef with two or four exposed sides for Biot numbers ranging between 0 and 3. In this range it predicts temperature vs time behavior with errors of less than 5 to 10% in terms of overall processing time. By using numerical methods, the approach used can be extended to handle problems involving time‐varying boundary conditions and many types of non‐linear, physical‐property behavior.
Cellular Electrode for Antitumor Drug Screening
Authors: Liang Bernard S. , Li Xiang‐Ming , Wang Henry Y.
Published: December 2008

Mouse leukemia L1210, a well established tumor model, can be immobilized near the surface of a dissolved O2 probe and its O2 uptake can be monitored continuously following the addition of various chemicals such as Mechlorethamine HCl, an antitumor agent. The output current of the O2 electrode changed as a function of time under various experimental conditions. The dynamic response of the electrochemical sensor was determined as a function of antitumor agent concentration. A preliminary kinetic model was developed to describe the biosensor behavior.
Experimental Device and Methods for Studying Milk Deposit Formation on Heat Exchange Surfaces
Authors: Tissier J. P. , Lalande M.
Published: December 2008

An experimental mini‐heat‐exchanger was developed in our laboratory.

It can be inserted between the heating and holding sections of a pilot milk pasteurizer without modifying its temperature gradient. Representative soil samples from both heating and holding sections were obtained. Changes in soil composition according to running time were studied over a range of 1 min to 4 hours. Previously cleaned 0.4 mm thick stainless steel plates (304L) had to be cut into pieces before analysis. Different kinds of results were obtained. Scanning electron microscopy showed that the deposit was composed of two different types of soil. A dense deposit could be observed near the metal surface after only 1 min of treatment; the thickness of this deposit increased to 15 μm during the process. Over this layer, a spongy deposit only slightly bound to the former, could be observed Lightly fouled plates were analyzed by “in situ techniques” (X.P.S.)

Thick deposits were embedded and sectioned for transmission electron microscopy and histochemical analyses.

A microanalytical method was applied to deposits after removal and resulted in detection ranges exceeding 10 mg/cm2.
Purification of Proteins and the Disruption of Microbial Cells
Authors: Kula Maria‐Regina , Schütte Horst
Published: December 2008

Intracellular proteins with catalytic or biological activity are of growing importance for developments in enzyme technology, as well as for the production of mammalian proteins by recombinant‐DNA technology. The release of these proteins from microorganisms is an important unit operation, as it is the first step in their isolation.

Gram‐scale disruption of microorganisms can be performed by a variety of established methods based on chemical, enzymatic, physical, or mechanical principles. For the large scale disruption of microorganisms, mechanical disintegrators, such as high‐speed agitator bead mills or high‐pressure industrial homogenizers, are commonly employed. Both types of equipment were designed originally for other tasks; in the paint industry or in the milk industry, respectively. Therefore, it appeared necessary and possible to improve design and performance for the application in cell disintegration. The goal is a uniform exposure of the microbial cells and a minimal exposure of solubilized protein to high shear forces, in order to obtain high yields and to avoid the generation of too small cell wall fragments, which are difficult to separate.

Both types of machines have been investigated for the disintegration of different microbial cells and the influence of the operating parameters analyzed on protein solubilization and enzyme yield. We will summarize the state of the art and discuss new data to illustrate trends in process development.
Purification of Monoclonal Antibodies from Large‐Scale Mammalian Cell Culture Perfusion Systems
Authors: Scott Randy W. , Duffy Stephen A. , Moellering Bill J. , Prior Christopher
Published: December 2008

Methodology for the purification of monoclonal antibodies from large‐scale mammalian cell culture systems has been investigated. The concentration of monoclonal antibodies in conditioned cell culture media was generally found to be in the milligram per liter range, requiring 100–1,000 liters for production of gram quantities. To reduce the volumes, several ultrafiltration systems, including hollow fiber, plate, and frame, and spiral cartridges were investigated and found to be effective for large‐scale work. Once a concentrated product was obtained, several methods including ammonium sulfate precipitation, ion exchange, protein. A agarose, and size exclusion chromatograhy were utilized and compared. The best results were obtained when concentrated conditioned medium was either diluted or diafiltered (to reduce the high ionic strength of conditioned medium) and fractionated by cation exchange chromatography. Variations in isoelectric points for different monoclonal antibodies require that specific pH and ionic strength parameters be determined to optimize binding and elution. Additional purification was achieved by further ion exchange steps or the use of ammonium sulfate precipitation. For particularly difficult purifications, protein A affinity chromatography was used. Once a purity of 90–95% was achieved, size exclusion chromatography was used as a final step to remove aggregates, process chemicals, contaminant proteins, and to exchange the antibody into the formulation buffer.
Biologically Active Surfaces: Processes Governing the Formation and Persistence of Biofilms
Authors: Bryers James D.
Published: December 2008

Current research concerning the physical, chemical, and biological processes governing biofilm formation and peristence is reviewed. Biofilm formation processes are explained. Potential research directions in the areas of physical, biological, and genetic control of biofilm processes are also presented.
An Analysis of Intra‐Versus Extracapillary Growth In a Hollow Fiber Reactor
Authors: Adema E. , Sinskey A. J.
Published: December 2008

Mammalian cell culture in hollow fiber reactors is hampered by oxygen limitation. Diffusive oxygen transport from the fiber wall to the cells can be enhanced by increasing the surface area for oxygenation and/or decreasing the penetration depth. One strategy for improving of surface area to penetration depth ratio is to increase the number of fibers in the reactor. An alternative way to manipulate this ratio is to grow the cells inside the fibers rather than on the outside. The theoretical analysis presented indicates that this is favorable when the volume of the extracapillary space exceeds that of the fiber lumen by a factor four or more. The impact of growing the cells on the inside of the fibers on other aspects of mammalian cell culture in hollow fiber reactors, including mass transport from the bulk of the medium flowing through the reactor to the fiber wall, is discussed.
Analysis of Urea Hydrolysis by Immobilized Urease in Urea‐Sensing Electrodes
Authors: Moynihan H. J. , Wang N.‐H. L.
Published: December 2008

Urea hydrolysis in an enzyme electrode that is sensitive to urea concentration has been analyzed with a theoretical model. The model incorporates nonlinear product‐inhibited, pH‐dependent kinetics, Nernst‐Planck diffusion, and ionic equilibria of product and buffer species. Simulation results indicate that film resistance can significantly reduce the detection range of the electrode and a Biot number (the ratio of characteristic internal to external mass transfer resistance) greater than 75 is necessary to minimize the film resistance. The electrode response depends on a balance between the reaction‐generated pH changes and the membrane diffusion resistances that sustain such pH shifts. The Damkohler number (the ratio of characteristic rate of reaction to that of diffusion) should be between one and five to maximize electrode sensitivity. The model has been used to demonstrate the effects of acetate, phosphate, and Tris buffers on electrode response. The carbonate concentration of dialysate solution is sufficient to shift the detection range of the electrode and reduce the sensitivity of the electrode by an order of magnitude. Tris buffer reduces the pH response of the electrode for buffer concentrations greater than 2 mM, because the pK of Tris falls within the range of the reaction‐generated pH shift.
Effective Diffusion Coefficients in Calcium Alginate Gel
Authors: Itamunoala G. F.
Published: December 2008

The effective diffusion coefficient of glucose, De in calcium alginate gel determined at 35°C by two different methods gave values which, on average, were at least 24% less than in water. Assessment of the effect of glucose concentration on De seems to indicate that De increased with decreasing glucose concentration at very low concentrations (i.e., < =100 mM) and increased with increasing glucose concentrations at high concentrations (i.e., > =200 mM). Increasing the concentration of either the calcium chloride or sodium alginate component used in calcium alginate formation substantially decreased De, but the effect of sodium alginate was the greater of the two.
Microbial Catabolites as Chemical Synthesis Intermediates: A Cost‐Benefit Analysis
Authors: Johnston J. B. , Winicov H. , Cunningham V. L.
Published: December 2008

Cost projections have been developed for a biologically mediated synthesis. Significant cost advantages can be realized using the biochemical approach.
The Effect of Detergent Level and Dispersion Rheology on the Olefin Yield from Fractionation of Tallow
Authors: Glassner David A. , Grulke Eric A.
Published: December 2008

Optimization of the detergent fractionation of tallow to maximize olein yield depends on selecting the correct detergency and rheological properties of the aqueous dispersion. The efficiency of the separation is related to the apparent viscosity of the mixture. The apparent viscosity of the dispersion as determined in a paddle mixer viscometer decreased from .3 Pa‐s to .1 Pa‐s as the olein yield increased from 66% to 79%.
Improvements In Multi‐Turbine Mass Transfer Models
Authors: Bader Fredric G.
Published: December 2008

Mathematical modeling approaches are being developed to better understand and describe the overall performance of large‐scale agitated fermentors. These new approaches are based upon subdividing the fermentor into various mixing cells, or stages. The further development of these models requires information on the power input per stage, its effect on mass transfer within the stage, fluid mixing patterns between stages, and the distribution of gas in the fermentor stages. The following discussion presents data and comments related to these topics for aerobic fermentations of low to medium viscosity.
A Simulation of the Effects of Formula Variations on the Transient Output of Single Screw Food Extruders
Authors: Levine Leon , Symes Steven , Weimer John
Published: December 2008

A simulation of the transient response of single screw extruders to fluctuations in formula of the extrudate is described. Any changes in extrudate composition, which result in changes in the viscous properties of the extrudate, result in transient behavior in the output of an extruder. Using existing extruder models, a simulation was used to study the transient behavior of an extruder in response to compositional variations in the extrudate. The results of the simulation suggest that for small variations in the composition of the material being extruded, large transient responses in extruder output will be observed. Depending on the relationship between the composition and viscosity of the extrudate, the change in output of the extruder can vary between insignificance and virtual stoppage of flow. The implications of these extruder transients on the design and operation of extrusion systems are discussed.
A Simulation of the Effect of Formula and Feed Rate Variations on the Transient Behavior of Starved Extrusion Screws
Authors: Levine Leon , Symes Steven , Weimer John
Published: December 2008

Using simulation, the steady state performance and transient behavior of starved extrusion screws are described. At steady state the filled length of the extruder is controlled by the relative resistance of the screw and die to flow, the flow index of the extrudate, and the feed rate to the extruder. For transient situations, small variations in the composition or feed rate of the material being extruded can significantly alter the extruder's output and filled length. Because of the broader residence time distribution of a twin screw extruder compared to a single screw extruder, the magnitude of the transient effects are seen to be smaller for twin screw extruders. The predicted output transients for extruders operated in the starved condition are of significantly lower magnitude than that for extruders operated in a filled condition. The implications of these effects on the design and operation of extrusion systems are discussed.
Use of Orthogonal Collocation Approximation for Parameter Identification and Control Optimization of a Distributed Parameter Biological Reactor
Authors: Isaacs S. , Thoma M. , Munack A.
Published: December 2008

The orthogonal collocation method of approximation is applied to the differential equations describing the oxygen concentration profiles in the liquid and gas phases of the tower loop airlift reactor. This provides a relatively quick simulation method that can be used for the parameter identification and control optimization tasks of the Open Loop Feedback Optimal (OLFO) adaptive control algorithm. Results of simulated cell mass fermentations are compared to that of a slower, more accurate finite difference simulation method showing the effects of collocation order on approximation accuracy and computation time. An example of parameter identification of the spatially dependent oxygen mass transfer coefficient and the overall growth rate is provided. Also, an example is included showing the optimization of air feed rate policy over the course of a fermentation.
Cooperative Binding of Sucrose in Xanthan Gum Solutions
Authors: Torrestiana Beatriz , Galindo Enrique , Brito Edmundo
Published: December 2008

In the xanthan gum fermentation mass transfer mechanisms are complex due to the high viscosity of the broth. Diffusional mass transfer becomes very important in transport of solutes such as oxygen and sucrose in the polysaccharide solution. Nevertheless, this process can be affected by interactions between macromolecule and solute. The present study was designed to determine if xanthan gum interacts with sucrose. The data show that xanthan gum in solution possesses two interaction sites for sucrose. These interactions are adequately described by a cooperative binding model. Changes in ionic strength and pH did not affect either the number of sites or type of interaction.
Extremely Thermophilic Archaebacteria: Biological and Engineering Considerations
Authors: Kelly Robert M. , Deming Jody W.
Published: December 2008

Interdisciplinary interactions between molecular biologists, microbial ecologists, and biochemical engineers portend well for the biotechnological exploitation of novel extremely thermophilic methanogens and sulfur‐metabolizing archaebacteria.
Review of Liquid Mixing in Packed Bed Biological Reactors
Authors: Swaine Donald E. , Daugulis Andrew J.
Published: December 2008

The use of residence time distribution analysis to characterize the liquid phase hydrodynamics in bioreactors is reviewed, with special emphasis on packed bed bioreactors. The importance of tracer selection, the method of data analysis and other uses for the data collected in RTD measurements are discussed.
Bioproduct Recovery From Unclarified Broths and Homogenates Using Immobilized Adsorbents
Authors: Nigam Somesh C. , Sakoda Akiyoshi , Wang Henry Y.
Published: December 2008

The use of reversibly “immobilized” (gel‐matrix entrapped or gel‐membrane encapsulated) adsorbents for the recovery of protein products from unclarified broths or cell homogenates containing difficult to remove solids was investigated. The hydrogel membrane or matrix acts as a protective non‐fouling barrier that allows the diffusion of the desired bioproduct, but it excludes colloidal solids such as whole cells, cell debris, and macromolecular precipitates. This feature not only prevents the fouling of the adsorbent, it also enhances product separation. The concept of kinetic selectivity, which depends on the differences in the diffusion rates of various adsorbing species is also introduced. The utility of hydrogel matrix or membrane in enhancing the kinetic selectivity of smaller proteins from a crude mixture was also investigated using model systems.
NMR Spectroscopy Studies of Hybridoma Metabolism in a Simple Membrane Reactor
Authors: Fernandez Erik J. , Mancuso Anthony , Clark Douglas S.
Published: December 2008

Nuclear magnetic resonance (NMR) was used to examine the metabolism of hybridoma cells in a simple immobilized‐cell membrane reactor. Although the reactor was not suitable for maintaining viable cells over extended periods, several types of experiments were performed. Phosphorylated and carbonaceous metabolites were observed on‐line with 31P and 13C NMR. Complementary information about glutamine metabolism was provided by 15N NMR spectra of concentrated supernatants. Extracellular contributions to NMR spectra were measured in a second vessel containing only medium. 3IP NMR measurements demonstrated that the perfused cells were stable to changes in the concentration of dissolved oxygen and to a brief interruption in medium recirculation. In tracer experiments utilizing [I‐13C]D‐glucose as a substrate, lactate and alanine were detected in vivo, along with some as of yet unassigned compounds. When cells were exposed to a high initial concentration of [I‐13C]D‐glucose, lactate and alanine appeared immediately and attained their maximum recorded levels at similar times. When cells were subjected to a step change in the glucose concentration from 2–10 mM, intracellular lactate and nucleoside triphosphates (NTP) increased sharply, but alanine formation was not evident until nearly five hours later. In both cases, the intracellular concentrations of labeled lactate and alanine were estimated directly from the 13C NMR spectra.
Intracellular Proteins Produced by Mammalian Cells in Response to Environmental Stress
Authors: Goochee Charles F. , Passini Cheryl A.
Published: December 2008

A condensed review of the literature on mammalian cells focusing on aspects of particular interest to biochemical and biomedical engineers.
Formulation and Characterization of a Multiple Emulsion for Use as a Red Blood Cell Substitute
Authors: Borwanker C. M. , Pfeiffer S. B. , Zheng S. , Beissinger R. L. , Wasan D. T. , Sehgal L. R. , Rosen A. L.
Published: December 2008

A new approach to the development of an oxygen‐carrying blood substitute is presented. The development of a viable blood substitute in the form of a multiple emulsion encapsulating hemoglobin solution was explored. Results indicated that the formulation ingredients and procedure affect the properties of the multiple emulsion. In order to evaluate the different formulations a quantitative method of assessing the encapsulation efficiency (yield) of the multiple emulsions was developed. The yield test measures the amount of hemoglobin released into the external phase. A model mutiple emulsion was formulated and characterized by yield, drop size distribution, oxygen‐carrying capacity, oxyhemoglobin dissociation, short‐term storage stability, and viscosity. The yield obtained for the model formulation was excellent (greater than 90%) giving high oxygen‐carrying capacity. The high yield was maintained over a four day storage period at 4d̀C.
Endothelial Volume and the Hydraulic Conductivity of Microvessels During Altered Pressure States
Authors: Easterbrook M. H. , Gross J. F. , Intaglietta M.
Published: December 2008

Low perfusion states of the microcirculation are known to produce endothelial cell swelling. In our study, irreversible thermodynamic transport equations are used to model the exchange of fluid between endothelial cells and the blood and tissue compartments. Results indicate that changes in the capillary hydrostatic pressure result in negligible radius changes, due to the small contribution of this pressure to the total pressure when the osmotic pressures of all species present are taken into account. Alterations in osmotic pressure via adjustment of the NaCl concentration in the blood produce fast and substantial changes in radius and therefore hydraulic resistance.
Reaction Rates for the Production of Polyphenylalanine and Polyserine by Solid Phase Peptide Synthesis with Low Excesses of the Symmetrical Anhydride
Authors: Chen Wen‐Yih , Foutch Gary L.
Published: December 2008

Continuous monitoring with UV‐absorbance was used to obtain coupling reaction rates between t‐Boc amino symmetrical anhydrides and the amino terminus of the peptide by solid phase synthesis. A kinetic model was established for the synthesis of polyserine and polyphenylalanine with rate constants determined over selected reaction temperatures, mixing rates, peptide chain lengths, and excess mole ratios of t‐Boc amino acid.
Effects of Growth Conditions on Carbon Utilization and Organic By‐Product Formation in B. subtilis
Authors: Snay J. , Jeong J. W. , Ataai M. M.
Published: December 2008

The effects of growth rate and substrate concentration on cellular metabolism of glucose was studied with cultures of B. subtilis 168. Application of chemostat culture techniques allowed for the observation of each growth condition independent of the other. The relative flux of carbon through biosynthetic and non‐biosynthetic pathways was determined by monitoring cell density and distribution of extracellular side products in active cultures. A metabolic shift of glucose utilization pathways was observed in cell cultures grown at dilution rates greater than 0.36 hr−1 or with glucose feed levels exceeding 10 gll. The predominant side products detected by HPLC analysis were acetic acid, formic acid, lactic acid, and acetoin. The patterns of side product formation were analyzed in relation to the applied growth conditions.
Adsorption Phenomena in Hydrophobic Interaction Chromatography
Authors: Roettger Belinda F. , Myers Julia A. , Ladisch Michael R. , Regnier Fred E.
Published: December 2008

Hydrophobic interaction chromatography (HIC) separates proteins on the basis of surface hydrophobicity while generally retaining the activity of proteins. Aqueous mobile phases with high salt concentrations are often used to adsorb the proteins onto a mildly hydrophobic support. HIC protein adsorption is modeled using the thermodynamic theory of linked functions (i.e., Wyman's linkage theory). This approach correlates adsorption to preferential interactions of the salts with supports and proteins. Two different methods were employed to study the salt interactions with the support: chromatography retention studies and densimetric techniques. Results of the salt chromatography trials indicate that chaotropic salts such as NaSCN and NaI have positive preferential interaction parameters that decrease with increasing concentration. Densimetric measurements show that the preferential interaction parameters of polar kosmotropic salts, such as ammonium sulfate are negative and become more negative with increasing concentration. The correlation of HIC adsorption to preferential interaction parameters was experimentally verified by retention studies of lysozyme in aqueous chaotropic and kosmotropic mobile phases, which also show a linear relation between the protein's capacity factor and the lyotropic series.
A Novel Optical Method for the Measurement of Biomolecular Diffusion in Polymer Matrices
Authors: Thomas Susan N. Behrens , Blanch Harvey W. , Soane David S.
Published: December 2008

A novel fiber optic probe was developed and used to investigate the mass transport of proteins through a polyacrylamide matrix. The basic component of the probe was an optical fiber, employing the evanescent wave as an excitation source for molecules near its surface. The optical fiber was coated with a very thin film of polyacrylamide, and the rate of diffusion through this matrix for proteins tagged with FITC (fluorescein isothiocyanate) was determined. The diffusivity of FITC‐β‐galactosidase was 1.6 × 10−10 cm2/sec. A bimodal distribution in size was observed in the albumin sample, with the diffusivities of the two components differing by an order of magnitude (D1 = 4.9 × 10−10 cm2/sec, D2 = 3.5 × 10−10 cm2/sec). Studies were also performed to determine the effect of crosslinking the matrix on the mass transfer of FITC‐albumin. The diffusion coefficient was reduced as the time of exposure to the crosslinking solution (triethylene diamine) increased. After twenty minutes of exposure to the crosslinking solution, the larger of the two albumin species was excluded from the matrix and only one diffusing species was detected.
Numerical and experimental evaluation of microfluidic sorting devices
Authors: Taylor Jay K. , Ren Carolyn L. , Stubley G. D.
Published: December 2008

The development of lab‐on‐a‐chip devices calls for the isolation or separation of specific bioparticles or cells. The design of a miniaturized cell‐sorting device for handheld operation must follow the strict parameters associated with lab‐on‐a‐chip technology. The limitations include applied voltage, high efficiency of cell‐separation, reliability, size, flow control, and cost, among others. Currently used designs have achieved successful levels of cell isolation; however, further improvements in the microfluidic chip design are important to incorporate into larger systems. This study evaluates specific design modifications that contribute to the reduction of required applied potential aiming for developing portable devices, improved operation reliability by minimizing induced pressure disturbance when electrokinetic pumping is employed, and improved flow control by incorporating directing streams achieving dynamic sorting and counting. The chip designs fabricated in glass and polymeric materials include asymmetric channel widths for sample focusing, nonuniform channel depth for minimizing induced pressure disturbance, directing streams to assist particle flow control, and online filters for reducing channel blockage. Fluorescence‐based visualization experimental results of electrokinetic focusing, flow field phenomena, and dynamic sorting demonstrate the advantages of the chip design. Numerical simulations in COMSOL are validated by the experimental data and used to investigate the effects of channel geometry and fluid properties on the flow field.
Transfection‐induced defects in dynein‐driven transport: evidence that ICs mediate cargo‐binding
Authors: Towns William L. , Tauhata Sinji B.F. , Vaughan Patricia S. , Vaughan Kevin T.
Published: December 2008

Cytoplasmic dynein contributes to the localization and transport of multiple membranous organelles, including late endosomes, lysosomes, and the Golgi complex. It remains unclear which subunits of dynein are directly responsible for linking the dynein complex to these organelles, however the intermediate chain (IC), light intermediate chain (LIC) and light chain (LC) subunits are each thought to be important. Based on previous mapping of a dynein IC phosphorylation site (S84), we measured the impact of transfected ICs on dynein‐driven organelle transport (Vaughan et al.,2001). Wild‐type and S84A constructs disrupted organelle transport, whereas the S84D construct induced no defects. In this study we investigated the mechanisms of transfection‐induced disruption of organelle transport. Transfected ICs did not: (1) disrupt the dynein holoenzyme, (2) incorporate into the native dynein complex, (3) dimerize with native dynein ICs or (4) sequester dynein LCs in a phosphorylation‐sensitive manner. Consistent with saturation of dynactin as an inhibitory mechanism, truncated ICs containing only the dynactin‐binding domain were as effective as full‐length IC constructs in disrupting organelle transport, and this effect was influenced by phosphorylation‐state. Competition analysis demonstrated that S84D ICs were less capable than dephosphorylated ICs in disrupting the dynein‐dynactin interaction. Finally, two‐dimensional gel analysis revealed phosphorylation of the wild‐type but not S84D ICs, providing an explanation for the incomplete effects of the wild‐type ICs. Together these findings suggest that transfected ICs disrupt organelle transport by competing with native dynein for dynactin binding in a phosphorylation‐sensitive manner. Cell Motil. Cytoskeleton 2009. © 2008 Wiley‐Liss, Inc.
SN2′ Boron‐Mediated Mitsunobu Reactions – A New One‐Pot Three‐Component Synthesis of Substituted Enamides and Enol Benzoates
Authors: Berrée Fabienne , Gernigon Nicolas , Hercouet Alain , Lin Chia Hui , Carboni Bertrand
Published: December 2008

The conversion of (3‐hydroxy‐1‐propen‐1‐yl)boronates to substituted enamides and enol benzoates is readily achieved in a one‐pot procedure consisting of a regiocontrolled Mitsunobu reaction with convenient nucleophiles, followed by allylboration of aldehydes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Embodied emotion concepts: How generating words about pride and disappointment influences posture
Authors: Oosterwijk Suzanne , Rotteveel Mark , Fischer Agneta H. , Hess Ursula
Published: December 2008

Embodiment theories predict that activating conceptual knowledge about emotions can be accompanied by re‐experiencing bodily states, since simulations of sensory, motor, and introspective experiences form the foundation of conceptual representations of emotion. In the present study, we examine whether the activation of the specific emotion concepts of pride and disappointment are embodied in the sense that they are accompanied by changes in posture. Participants generated words associated with pride and disappointment while posture height was measured. Results show that during the generation of disappointment words participants decreased their posture height more than when participants generated pride words. This finding suggests that the activation of conceptual knowledge about disappointment can lead to a spontaneous expression of the associated body posture. In contrast to posture changes along the vertical axis, movement along the horizontal axis was not influenced by concept activation. In addition to bodily simulation the data also indicated introspective simulation, since feelings of disappointment increased after generating disappointment words. The current study provides the first evidence for the claim that the activation of conceptual knowledge about emotion can instantiate spontaneous simulations at a behavioral level. Copyright © 2008 John Wiley & Sons, Ltd.
Glial cell type‐specific subcellular localization of 14‐3‐3 zeta: An implication for JCV tropism
Authors: Lamba Shivani , Ravichandran Veerasamy , Major Eugene O.
Published: December 2008

14‐3‐3 Isoforms are shown to be upregulated or accumulated in the glial cells of autopsied patient brains affected with progressive multifocal leukoencephalopathy (PML), a demylinating disease caused by JC virus (JCV). The possible involvement of 14‐3‐3 in JCV tropism, however, has never been examined. To investigate a potential relationship between 14‐3‐3 isoforms and JCV in vitro, we examined the localization of six 14‐3‐3 isoforms in human neural progenitors and progenitor‐derived astrocytes (PDAs) in cells without JCV exposure. The 14‐3‐3 zeta isoform was initially localized in the progenitor cytoplasm. When differentiation of progenitors into PDAs was induced, the zeta isoform was translocated into the nucleus. However, upon JCV infection, progenitor cells exhibited an uncharacteristic 14‐3‐3 zeta nuclear presence in the few cells that became infected. JCV‐treated PDAs showed elevated levels of 14‐3‐3 zeta compared with noninfected PDAs. Treatment with TGF‐β1, a known stimulant of JCV multiplication, increased the overall number of infected cells and the otherwise absent nuclear presence of 14‐3‐3 zeta in progenitors. These results suggest that the nuclear presence of 14‐3‐3 zeta may play a role in JCV infection, and that the isoform may in part determine JCV susceptibility in these cell types. © 2008 Wiley‐Liss, Inc.
Rethinking college readiness
Authors: Conley David T.
Published: December 2008

Students vary in the degree to which high school and family life prepare them for college, and that preparation has a dramatic impact on their transition to college and subsequent success there.
Adult students in higher education: A portrait of transitions
Authors: Hardin Carlette Jackson
Published: December 2008

Adult students, whether new or returning to higher education, experience a unique set of transition challenges. By understanding the characteristics and needs of this student cohort, colleges and universities are better able to facilitate adult student success.
Sophomores in transition: The forgotten year
Authors: Tobolowsky Barbara F.
Published: December 2008

Although the nature of collegiate transition in the sophomore year is different from that of first‐year students, it is no less significant or challenging.
Institutional efforts to move seniors through and beyond college
Authors: Henscheid Jean M.
Published: December 2008

The last of the formal undergraduate transitions is the one out of college and back to either the “real world” or graduate or professional study. The senior year transition embodies both opportunities and challenges for students and institutions.