bluuebunny/crossref_metadata_2025_split huggingface dataset:
TRADE-OFFS BETWEEN FORAGE YIELDS AND FEED QUALITY OF LABLAB PURPUREUS, AND MILK YIELDS IN RELATION TO PLANTING AND HARVESTING SCHEDULES
Authors: AGYEMANG K. , OKIKE I. , MAKUN H. J. , MAGAJI S. O. 
Published: March 2005

This study, designed to investigate trade-offs between forage yields, feed quality and labour use in fitting a newly introduced crop, Lablab purpureus, into an existing farming system, adopted distinct applied and adaptive research approaches. The applied research component compared forage yields, nutrient contents and feeding qualities of L. purpureus harvested at 100, 114, 128 or 142 d after planting in an on-farm trial. The adaptive research investigated how farmers incorporated L. purpureus cultivaton into their farming calendars given the constraints of labour for planting and harvesting.Harvested dry matter yields from the on-farm experiment were 1.28, 1.98, 1.74 and 1.44 t ha−1. The resultant hays were fed to four groups each of five Bunaji lactating cows in an on-farm feeding trial over a 10-week period. Ranking the various harvests for yield, the hays for feed value, animal responses to the feed consumed and the quality of animal products on a linear scale (1 to 4) to estimate a composite utility index, showed that harvesting at 114 d after planting gave the most desirable overall benefits.The survey for adaptive research showed bimodal rainfed and irrigated cultivation patterns for L. purpureus. Peaks were observed in September (31% of farmers) and November (24%) for planting, and in December (39.4%) and March (15%) for harvesting. Forage yields were, however, highest for the 3% of farmers who afforded labour to plant in July and harvest in October. The lack of congruence between highest forage yield periods and the peaks of cultivation of L. purpureus by farmers in the study area was mostly explained by very significant differences in the cost of hired and household labour in different months. Thus, socio-economic and cultural factors, including stakeholders' participation, need to be considered along with applied research results when recommending forage species for farmers' adoption.
Sugar Separations on a Pilot Scale by Continuous Annular Chromatography
Authors: Byers Charles H. , Sisson Warren G. , Decarli Joseph P. , Carta Giorgio 
Published: March 2005

AbstractA pilot‐scale continuous annular chromatograph has been developed for scale‐up and optimization studies. The chromatographic apparatus consists of a slowly rotating annular bed of sorbent material. The feed mixture which is to be separated is continuously introduced at a stationary point at the top of the bed, while eluent flows over the remainder of the annulus. The rotation of the sorbent bed coupled with the elution development induced by the downflow of eluent causes the feed components to appear as individual helical bands, each of which has a characteristic, stationary exit point. The separation of sucrose, glucose, and fructose, using the calcium form of a cation‐exchange resin, was investigated using water as the eluent. Experiments were carried out both with a synthetic mixture of the sugars as well as with an industrial feedstock. The separation was explored first in a bench‐scale conventional fixed‐bed column and then in the pilot‐scale continuous chromatograph. Factors such as column loading, feed‐to‐eluent ratio, and feed concentration were investigated both experimentally and theoretically. The results of bench‐scale experiments were carried out in the limit of infinite dilution, almost perfectly scaled to the pilot unit when loading was low and feed mixtures were of low viscosity. Very significant deviations from ideality were, however, observed at high feed loadings, when the feed viscosity exceeded that of the eluent by more than a factor of 2.
Affinity Cross‐Flow Filtration: Some New Aspects
Authors: Herak David C. , Merrill Edward W. 
Published: March 2005

AbstractA variety of affinity cross‐flow filtration (ACFF) experiments were conducted to evaluate the technique as a means of effectively separating biomolecules. Agarose particles, which contained a specific affinity ligand for the targeted protein, were used as “affinity escorts” in the ACFF process. Both conventional agarose particles (40–150; μm) and small agarose particles (Superose, 11–15 μm.) were used as the basis for affinity escorts. Batch ACFF washing experiments were conducted in both constant‐volume and volume‐reduction modes and compared with model predictions. The different affinity ligand‐adsorbate systems studied include Cibacron Blue and human serum albumin, Cibacron Blue and lysozyme, protein A and immunoglobulin G, and concanavalin A and horseradish peroxidase.
Selective Extraction Using Functionalized Poly(organosiloxanes)
Authors: England R. , Abed‐Ali S. S. , Brisdon B. J. 
Published: March 2005

AbstractThere are two major separation problems that frequently impede the successful isolation of fine chemicals and biological materials from aqueous media. These concern either (a) the selective recovery of low concentrations of products from complex mixtures or (b) the purification of high‐value products by selective and efficient removal of contaminants. The recovery of biotransformation products with frequently small chemical and physical differences between reactant and product, from bioreactor broths containing low product concentrations as well as nutrients and extraneous salts, typifies the former problem. We have used fluid polymers functionalized with molecular receptors capable of interacting specifically with the required products in the fermenter broth, to provide a basis for separation. Thus, attachment of various crown ethers to a hydrophobic polysiloxane backbone via an alkyl spacer chain yields functionalized, liquid, linear polymers of the type Me3Si(OSiMe2)x(OSiMe(CH2)n — crown)yOSiMeg3, which are able to preferentially complex, and hence extract, specific types of amines from aqueous mixtures. This molecular recognition technique has been successfully applied to the separation of N‐demethylated drug molecules produced by Cunninghamella sp. in bioreactors. The efficiency of extraction from the fermenter broth and recovery of the product from the functionalized polymer has been determined for this system. Attachment of other receptors to polysiloxane fluids is currently being investigated in order to extend the range of application of this class of discriminating extractant. Initial studies have also been made on applying the technique to problem b, using similarly functionalized polymers to selectively decontaminate complex macromolecular systems. Results indicate that amine contaminants can be removed from some proteins in a single‐batch extraction but that an interaction occurs on direct contact between the protein and functionalized polymers. Studies utilizing supported liquid membranes for the separation of various amines and amino acids are currently under investigation, and preliminary results show that the method is superior to direct liquid/liquid extraction.
Shear Sensitivity of Hybridoma Cells in Batch, Fed‐Batch, and Continuous Cultures
Authors: Petersen Jonathan F. , Mclntire Larry V. , Papoutsakis Eleftherios Terry 
Published: March 2005

AbstractPreviously, we observed that CRL‐8018 hybridoma cells were more sensitive to well‐defined viscometric shear during the lag and stationary phases than during the exponential phase of batch cultures. Some potential hypotheses for explaining the increase in shear sensitivity are (1) nutrient limitations that result in a decrease in production of specific cellular components responsible for the mechanical strength of the cell, (2) nutrient limitations that lead to synchronization of the culture in a cell cycle phase that is more sensitive to shear, or (3) a link between cell growth and shear sensitivity, such that slowly growing cells are more sensitive to shear. Here, the duration of the exponential phase was increased with use of fed‐batch, and the effect on shear sensitivity of the cultures was measured with a viscometric technique. Extension of exponential growth resulted in an increased period during which the cells were insensitive to shear. Additionally, the shear sensitivity of the cells was constant over a wide range of growth rates and metabolic yields in chemostat cultures. These observations suggest that as long as the cells are actively (exponentially) growing, their shear sensitivity does not depend on the growth rate or metabolic state of the cell as expressed by metabolic yields. Thus, hypothesis 3 above can be dismissed.
Biosynthesis of p‐Hydroxylated Aromatics
Authors: Salvo Joseph J. , Mobley David P. , Brown Daren W. , Caruso Lisa A. , Yake Andrew P. , Spivack Jay L. , Dietrich David K. 
Published: March 2005

AbstractA bioconversion process with Aspergillus parasiticus has been developed to enhance p‐hydroxylation activities with respect to aromatic substrates such as m‐terphenyl. Through modified growth conditions, we are improving product concentration, while streamlining fermentation and downstream processing requirements. We routinely carry out biosynthetic conversions with m‐terphenyl at the 300‐L scale and produce over 200 g of 4,4″‐dihydroxy‐m‐terphenyl at a concentration of 0.7 g/L in the fermentation vessel.
Simulation and Control of Glucose Concentration in Hot‐Water Blanching of Potatoes
Authors: Tomasula P. M. , Kozempel M. F. , Craig J. C. 
Published: March 2005

AbstractThe methodology for online monitoring and computer control of glucose concentration in potatoes during hot‐water blanching is demonstrated. Process conditions, control parameters, and setpoints are determined with the aid of an unsteady‐state model. Glucose concentration in the blanch water is monitored and maintained at a setpoint value by adjustment of the fresh water flow rate to the blancher, while the glucose concentration of the potatoes is calculated by mass balance. Control is effected through feedback and anticipatory feedback control. Results indicate that glucose concentration in potatoes exiting the blancher may be maintained within 10% of the setpoint value. The use of computers to control glucose concentration in potatoes should prove useful in the control of the color and therefore the quality of processed potato products.
Sizing Biological Samples by Photosedimentation Techniques
Authors: Middelberg Anton P. J. , Bogle I. David L. , Snoswell Mark A. 
Published: March 2005

AbstractThe performance of the Joyce‐Loebl disk centrifuge in the sizing of Escherichia coli cells, protein inclusion bodies, and cell debris is evaluated. The need for a density gradient that extends throughout the entire spin fluid is highlighted, and a set of standard conditions that fulfill this requirement is defined. E. coli cells experience a reduction in their Stokes diameter when exposed to ethanol, indicating that a spin‐buffer fluid combination such as glycerol‐water is to be preferred for the sizing of bacteria. The instrument baseline is influenced by the presence of particles, and a method of estimating the baseline is described. The sizing of small particles is further complicated by baseline drift due to temperature sensitivity of the optical yoke. An analysis of diffusion in the spin fluid is conducted, and an expression for the sedimentation:diffusive flux ratio is derived. For the current samples, it is shown that diffusion within the spin fluid does not lead to significant errors for 0.15‐μm particles, whereas the phenomenon may be significant at the manufacturer's size limit of 0.01 μm.
N‐Laurylbiotinamide as Affinity Surfactant
Authors: Coughlin Robert W. , Baclaski Jeffrey B. 
Published: March 2005

AbstractN‐laurylbiotinamide (NLB), which retains strong affinity for the protein avidin, was synthesized from biotin and N‐laurylamine via the biotin ester of N‐hydroxysuccinimide and characterized by NMR. When the synthesized NLB was used as a cosurfactant with AOT to form a reverse micellar system in isooctane, it was found to extend the pH range over which avidin can be transferred from a continuous aqueous solution to the reverse‐micellar phase. This behavior is similar to that already reported for a different affinity surfactant, n‐octyl β‐D‐glucopyranoside.
Improved Adsorption to Starch of a β‐Galactosidase Fusion Protein Containing the Starch‐Binding Domain from Aspergillus Glucoamylase
Authors: Chen Luojing , Ford Clark , Kusnadi Ann , Nikolov Zivko L. 
Published: March 2005

AbstractWe have previously shown (Chen et al., 1991) that a β‐galactosidase (β‐gal) fusion protein (BSB133) containing 133 amino acids (aa) from the C‐terminus of Aspergillus glucoamylase (GA) adsorbs strongly to starch compared to β‐gal, due to the presence of the GA starch‐binding domain. We have now made deletions at the N‐terminus of this 133‐aa region to test the minimal size required for starch binding of β‐gal fusion proteins. Three fusion proteins (BSB119, BSB103, and BSB80) were genetically engineered, containing 119, 103, and 80 C‐terminal aa from GA, respectively. The fusion proteins were expressed in Escherichia coli and purified. Purified BSB119 adsorbed to native starch at least 2‐fold more strongly than did BSB133 or fusion proteins with shorter tails. Adsorption isotherms generated over a wide range of initial concentrations indicated a 10‐fold difference in the loading capacity of starch for BSB119 (36.5 mg of protein/g of starch) compared to β‐gal (3.7 mg of protein/g of starch). Adsorption constants calculated from the initial slopes of the isotherms indicated a nearly 30‐fold difference in affinity to starch for BSB119 (Kad = 63 mL/g of starch) compared to β‐gal (Kad = 2.3 mL/g of starch). BSB119 in the presence of crude enzyme extracts also bound to starch with a high affinity compared to a β‐gal control. Potential applications of the starch‐binding tail include enzyme immobilization to starch or recovery and purification of target proteins from crude extracts.
Mathematical Modeling of Biochemical Changes during Processing of Liquid Foods and Solutions
Authors: Datta Ashim K 
Published: March 2005

AbstractThermal processing of liquid food materials and biochemical solutions always results in a distribution of biochemical changes such as bacterial and nutrient concentrations due to variation in temperature history from one liquid element to another. To estimate such distributions, the liquid elements need to be “tagged” and followed, which is computationally difficult for most flow situations of interest. This paper describes a computational procedure for obtaining the full range of biochemical changes during processing without explicitly following liquid elements. By use of the method developed, transient distributions of bacterial death have been obtained for sterilization of liquid in a nonagitated cylindrical enclosure heated from all sides. The conventional procedure of obtaining sterilization based on temperature at the slowest heating zone is shown to be lower than the actual least sterilization of a real fluid element in the system. Nutrient distributions can be similarly calculated by following this method.
Prediction of Moisture Diffusivity in Granular Materials, with Special Applications to Foods
Authors: Vagenas G. K , Karathanos V. T 
Published: March 2005

AbstractThe effective diffusion coefficient of two granular starch materials was determined from drying experiments by using the method of slopes. A method was developed, which permits the combination of the diffusion coefficient of the solid phase and the binary diffusion coefficient of water vapor in air for the prediction of the effective moisture diffusivity of the system. Several structural models of the literature were used to predict the effective moisture diffusivity of the two granular starches in the ranges of moisture content 0.0‐0.6 kg of water/kg of dry solids, porosity 0.0‐0.6, and temperature 20–100 °C. The results showed that the structural models can be successfully used for the prediction of the effective moisture diffusivity, and especially the Behrens model showed considerable merit. The diffusion coefficient of the solid phase (granule) was estimated by fitting the theoretical model to the experimental data.
Evaluation of Immunoglobulins from Plant Cells
Authors: Hein Mich B , Tang Ying , Mcleod Donald A , Janda Kim D , Hiatt Andrew 
Published: March 2005

AbstractExpression of cDNA constructs encoding full‐length mouse immunoglobulin chains with their native leader sequences or fusion constructs substituting the native leader with a pre‐pro sequence derived from Saccharomyces cerevisiae yielded blocked N‐termini on the γ chain or the correct amino terminal sequence on the mature k chain. Lectin binding assays revealed that assembled immunoglobulin complexes contained a glycosylated heavy chain. The attached glycan was resistant to digestion by endoglycosidase H and its lectin binding pattern was distinguishable from that of the mammalian glycan. The results indicated processing of the immunoglobulin carbohydrate in the tobacco Golgi to yield a complex oligosaccharide. Secretion of antibody by protoplasts isolated from regenerated transgenic plants or from suspension callus cells was demonstrated by pulse‐chase labeling experiments. When purified, the tobacco‐produced antibody was found to possess the antigen binding and catalytic properties of the murine monoclonal antibody. Kinetic parameters (Km, Ki, Vmax, and kcat) of the tobacco‐derived antibody were comparable to those of the mouse‐derived antibody. The results in general show that the endomembrane system of tobacco cells possesses cognate mechanisms for the recognition of diverse leader sequences. These signals can be used to initiate the assembly, processing, and secretion by plant cells of complex foreign proteins.
Plasmid Stabilization of an Escherichia coli Culture through Cycling
Authors: Stephens M. L. , Christensen C. , Lyberatos G. 
Published: March 2005

AbstractThe problem of plasmid instability of fermentations that involve plasmid‐bearing recombinant organisms is dealt with in this work. Previous theoretical work demonstrated that under certain conditions (where plasmid‐bearing species are slower in responding to changes in the fermentation environment than the wild species) the washout of the plasmid‐bearing species can be prevented. In the sequel, Weber and San showed that cycling the dilution rate can delay the washout of plasmid‐bearing species for a plasmid‐bearing Escherichia coli culture. This work shows that it is indeed possible to secure the presence of the plasmid‐bearing species at all times through appropriate cycling.
Release and Recovery of Porcine Pepsin and Bovine Chymosin from Reverse Micelles: A New Technique Based on Isopropyl Alcohol Addition
Authors: Carlson A. , Nagarajan R. 
Published: March 2005

AbstractAfter complete solubilization by the direct method, porcine pepsin was not released from AOT in isooctane reverse micelles even under aqueous‐phase conditions which would not ordinarily allow uptake. Similarly, bovine chymosin, once forward‐transferred at a pH below its isoelectric point, was not back‐transferred into an aqueous contact phase buffered at a pH value above its isoelectric point. These results show that there is significant hysteresis in the forward‐and backward‐transfer processes and further imply that kinetics, and not equilibrium, control uptake or release processes for these enzymes. The addition of 10–15 % isopropyl alcohol to the aqueous phase increases the rate of protein release dramatically and allows for nearly complete back‐transfer of porcine pepsin and 70% back‐transfer of bovine chymosin. IPA addition does not destroy the functional integrity of the system since forward transfer of bovine chymosin still occurs at pH values below (but not above) the pI of the protein.
Transient Association of the First Intermediate during the Refolding of Bovine Carbonic Anhydrase B
Authors: Cleland Jeffrey L. , Wang Daniel I. C. 
Published: March 2005

AbstractMany proteins which aggregate during refolding may form transiently populated aggregated states which do not reduce the final recovery of active species. However, the transient association of a folding intermediate will result in reduced refolding rates if the dissociation process occurs slowly. Previous studies on the refolding and aggregation of bovine carbonic anhydrase B (CAB) have shown that the molten globule first intermediate on the CAB folding pathway will form dimers and trimers prior to the formation of large aggregates (Cleland, J. L.; Wang, D. I. C. Biochemistry 1990, 29, 11072–11078; Cleland, J. L.; Wang, D. I. C. In Protein Refolding; Georgiou, G., De‐Bernardez‐Clark, E., Eds.; ACS Symposium Series 470; American Chemical Society: Washington, DC, 1991; pp 169–179). Refolding of CAB from 5 M guanidine hydrochloride (GuHCl) was achieved at conditions ([CAB]f=10–33 μM, [GuHCl]f=1.0 M) which allowed complete recovery of active protein as well as the formation of a transiently populated dimer of the molten globule intermediate on the refolding pathway. A kinetic analysis of CAB refolding provided insight into the mechanism of the association phenomenon. Using the kinetic results, a model of the refolding with transient association was constructed. By adjusting a single variable, the dimer dissociation rate constant, the model prediction fit both the experimentally determined active protein and dimer concentrations. The model developed in this analysis should also be applicable to the refolding of proteins which have been observed to form aggregates during refolding.
An Amperometric Alcohol Sensor Based on Chemically Permeabilized Methylotrophic Microorganisms
Authors: Chen Jhy‐Chern , Naglak Thomas J. , Wang Henry Y. 
Published: March 2005

AbstractChemical permeabilization of the yeast Pichia pastoris NRRL Y‐11430 with 1.0% glycine and 0.1 % Triton X‐100 does not release intracellular alcohol oxidase but alters the cell envelope structure, allowing alcohol oxidase activity to be detected inside the cells (Naglak, 1990). An alcohol sensor based on the use of chemically permeabilized yeast cells was constructed. The sensor response time was within 2 min. The assay time was less than 30s by the initial rate method. The calibration curve for ethanol analysis was linear in the range 5–65 mg/L. The sensor response was almost unaffected by pH changes within the range pH 5–9. This alcohol sensor produced the highest sensitivity for methanol; the sensitivity for ethanol was about half that for methanol. The stability and other characteristics of this new alcohol sensor are also discussed in this work.