Open Access. Powered by Scholars. Published by Universities.®

Chemical Engineering Commons™

Open Access. Powered by Scholars. Published by Universities.®

University of Nebraska - Lincoln

Discipline
Keyword
Publication Year
Publication
File Type

Articles 301 - 330 of 332

Full-Text Articles in Chemical Engineering

Fabrication Of Double Side Fully Metallized Plated Thru-Holes, In Polymer Structures, Without Seeding Or Photoprocess, Ravi F. Saraf Aug 1996

Fabrication Of Double Side Fully Metallized Plated Thru-Holes, In Polymer Structures, Without Seeding Or Photoprocess, Ravi F. Saraf

Department of Chemical and Biomolecular Engineering: Patents

The present invention is directed to a process of a method for the full metallization of thru-holes in a polymer structure comprising the steps of applying a film-forming amount of a conductive polymer-metal composite paste to a metal cathode; bonding a patterned polymer structure to said paste; subjecting said polymer structure to an electrolytic plating bath for a time sufficient to fully metallize thru-hole surfaces in said patterned polymer structure and removing the structure from the cathode assembly. The fully metallized thru-hole polymer structure can then be cleaned and polished to produce a finished product.

Go to article

Direct Chip Attachment (Dca) With Electrically Conductive Adhesives, Ravi F. Saraf Aug 1996

Direct Chip Attachment (Dca) With Electrically Conductive Adhesives, Ravi F. Saraf

Department of Chemical and Biomolecular Engineering: Patents

A simple process for card assembly by Direct Chip Attachment (DCA) uses electrically conductive adhesives. Two methods create the same intermediate wafer product with a layer of insulative thermoplastic and conductive thermoplastic bumps. After sawing or dicing the wafer to form the chips, the chips are adhered to chip carriers with conductive pads which match the conductive thermoplastic bumps, using heat and pressure. Chips may be easily removed and replaced using heat.

Go to article

Sulfur Tolerant Bimetallic Zeolitic Reforming Catalysts, Gustavo F. Larsen Jul 1996

Sulfur Tolerant Bimetallic Zeolitic Reforming Catalysts, Gustavo F. Larsen

Department of Chemical and Biomolecular Engineering: Patents

New compositions of matter comprise a metal from the group consisting of platinum, rhodium and palladium, a metal from the first row of Group VIII of the Periodic Table and a nonacidic L-zeolite. A preferred composition is Pt--Ni/KL-zeolite. Such catalysts are prepared by coimpregnation of the zeolite with the metals. Methods of using the catalysts in reforming, aromatization or dehydrogenation are provided.

Go to article

Polyelectrolyte Dna Conjugation And Genetic Transformation Of An Animal , William H. Velander Jun 1996

Polyelectrolyte Dna Conjugation And Genetic Transformation Of An Animal , William H. Velander

Department of Chemical and Biomolecular Engineering: Patents

Improved cellulosic beads for use as supports in bioaffinity chromatography are produced by dissolution of cellulose in a chaotropic cellulose solvent, formation of the dissolved cellulose into droplets, and immersion of the droplets into a non-solvent capable of solvent interchange with the cellulose solvent to form generally spherical porous cellulose beads of narrow particle size distribution. The beads formed are preferably made with cellulose having a degree of polymerization between 100 and 200, and the resulting beads when saturated with water without drying contain between 1% and 7% cellulose by weight and have a particle size of at least about …

Go to article

Experimental And Theoretical Study Of Vibrations Of A Cantilevered Beam Using A Zno Piezoelectric Sensor, B. R. Jooste, Hendrik J. Viljoen, S. L. Rohde, N. F. J. Van Rensburg May 1996

Experimental And Theoretical Study Of Vibrations Of A Cantilevered Beam Using A Zno Piezoelectric Sensor, B. R. Jooste, Hendrik J. Viljoen, S. L. Rohde, N. F. J. Van Rensburg

Hendrik J. Viljoen Publications

Piezoelectric sensors can measure vibrations of solid structures very accurately. A model of a cantilevered beam, with a ZnO film on one side is presented. Both viscous and internal damping are considered. The output of the sensor is modeled and matched with experimental results by adjusting the damping parameters. A theoretical formulation for damage is introduced. Experimental results for a damaged beam confirm the shift in frequencies to lower values. The model is used to identify the extent of the damage.

Go to article

Experimental And Theoretical Study Of Vibrations Of A Cantilevered Beam Using A Zno Piezoelectric Sensor, B. R. Jooste, Hendrik J. Viljoen, S. L. Rohde, N. F. J. Van Rensburg May 1996

Experimental And Theoretical Study Of Vibrations Of A Cantilevered Beam Using A Zno Piezoelectric Sensor, B. R. Jooste, Hendrik J. Viljoen, S. L. Rohde, N. F. J. Van Rensburg

Hendrik J. Viljoen Publications

Piezoelectric sensors can measure vibrations of solid structures very accurately. A model of a cantilevered beam, with a ZnO film on one side is presented. Both viscous and internal damping are considered. The output of the sensor is modeled and matched with experimental results by adjusting the damping parameters. A theoretical formulation for damage is introduced. Experimental results for a damaged beam confirm the shift in frequencies to lower values. The model is used to identify the extent of the damage.

Go to article

Analysis Of Homogeneous Combustion In Monolithic Structures, Hendrik J. Viljoen Apr 1996

Analysis Of Homogeneous Combustion In Monolithic Structures, Hendrik J. Viljoen

Papers in Chemical Reactions

An analytical method is used to solve the problem of homogeneous combustion in a monolith. The solid phase acts as burner support. Heat is conducted much more effectively in the solid phase and preheating of the gas is more effective. The flame temperature exceeds the adiabatic value. Solutions are presented for different velocities and feed concentrations.

Go to article

Heat Transfer In Rarefied Gas At A Gas-Solid Interface, Yaşar Demirel, Satish C. Saxena Feb 1996

Heat Transfer In Rarefied Gas At A Gas-Solid Interface, Yaşar Demirel, Satish C. Saxena

Papers in Physical Chemistry

Modified expressions for the heat-transfer fluxes at the interface of a solid surface and a gas are given for different Knudsen-number regimes. These expressions for diatomic gases contain both a gas-reflection and a thermal accommodation coefficient. Parallel-plate, coaxial-cylindrical and concentric spherical surfaces are considered. A general expression for the thermal accommodation coefficient is based on experimental data. Sample numerical calculations of heat flux in different heat-transfer regimes are presented in terms of the reciprocal Knudsen number.

Go to article

Reaction Fronts In A Porous Medium. Approximation Techniques Versus Numerical Solution, Fernando Escobedo, Hendrik J. Viljoen Mar 1995

Reaction Fronts In A Porous Medium. Approximation Techniques Versus Numerical Solution, Fernando Escobedo, Hendrik J. Viljoen

Papers in Reaction Kinetics

The flame sheet approximation (FS) and a novel polynomial approximation technique (PA) are compared in terms of their capability to describe reaction fronts of highly exothermic reactions in a porous medium. A one-phase model and a two-phase model of a system with adiabatic walls and a radiant output (to approximate the case of a porous radiant burner) are included in the analysis. By matching the reaction zone solution found by either the FS or PA method with the solutions of the nonreacting zones, the temperature, conversion, and position of the reaction zone were determined. Numerical solutions for catalytic and noncatalytic …

Go to article

Excess Heat Capacity Surfaces For Water-Alkanol Mixtures By The Uniquac Model, Yaşar Demirel, Halime Ö. Paksoy Mar 1995

Excess Heat Capacity Surfaces For Water-Alkanol Mixtures By The Uniquac Model, Yaşar Demirel, Halime Ö. Paksoy

Papers in Physical Chemistry

Hydroorganic mixtures are industrial solvents that can serve as media to solubilize either water in hydrocarbon or a hydrophobic substance in water. In many cases the solubilizing capability is obtained via a homogeneous complex aqueous mixtures containing an alcohol. Since excess heat capacity CPE, is very sensitive to structural changes in mixtures, concentration and temperature dependence of CPE have been calculated by using the UNIQUAC model for the mixtures methanol(l)-water(%, ethanol(l)-water(2), and l-propanol(l)-water(2). The temperature-dependent parameters of the model estimated directly from CPE data at more than one different isotherm are used in …

Go to article

Expression Of A Functional Human Complement Inhibitor In A Transgenic Pig As A Model For The Prevention Of Xenogeneic Hyperacute Organ Rejection., William L. Fodor, Barry L. Williams, Louis A. Martis, Josaeph A. Madri, Scott A. Rollins, James W. Knight, William H. Velander, Stephen P. Squinto Nov 1994

Expression Of A Functional Human Complement Inhibitor In A Transgenic Pig As A Model For The Prevention Of Xenogeneic Hyperacute Organ Rejection., William L. Fodor, Barry L. Williams, Louis A. Martis, Josaeph A. Madri, Scott A. Rollins, James W. Knight, William H. Velander, Stephen P. Squinto

Papers in Biotechnology

ABSTRACT The serious shortage of human organs available for transplantation has engendered a heightened interest in the use of animal organs (xenografts) for transplantation. However, the major barrier to successful discordant xenogeneic organ transplantation is the phenomenon of hyperacute rejection. Hyperacute rejection results from the deposition of high-titer preformed antibodies that activate serum complement on the luminal surface of the vascular endothelium, leading to vessel occlusion and graft failure within minutes to hours. Although endogenous membrane-associated complement inhibitors normally protect endothelial cells from autologous complement, they are species restricted and thus confer limited resistance to activated xenogeneic complement. To address …

Go to article

Lignocellulosic And Cellulosic Beads For Affinity And Immunoaffinity Chromatography Of High Molecular Weight Protiens, William H. Velander Jul 1994

Lignocellulosic And Cellulosic Beads For Affinity And Immunoaffinity Chromatography Of High Molecular Weight Protiens, William H. Velander

Department of Chemical and Biomolecular Engineering: Patents

Improved cellulosic beads for use as supports in bioaffinity chromatography are produced by dissolution of cellulose in a chaotropic cellulose solvent, formation of the dissolved cellulose into droplets, and immersion of the droplets into a non-solvent capable of solvent interchange with the cellulose solvent to form generally spherical porous cellulose beads of narrow particle size distribution. The beads formed are preferably made with cellulose having a degree of polymerization between 100 and 200, and the resulting beads when saturated with water without drying contain between 1% and 7% cellulose by weight and have a particle size of at least about …

Go to article

Unzippable Polymer Mask For Screening Operations, Ravi F. Saraf May 1994

Unzippable Polymer Mask For Screening Operations, Ravi F. Saraf

Department of Chemical and Biomolecular Engineering: Patents

The present invention relates to a dry process for forming patterns on a substrate. More particularly, the process contemplates coating an unzippable polymer film with a small amount of desirable UV if required on a substrate; laser ablating said film into a desired pattern or mask; screening a conductive or resistive paste onto the substrate through the ablated features of said mask; heating said substrate and mask to the unzipping temperature of said mask; and, vaporizing said mask and UV absorbing dye if present leaving behind the solid of said conductive or resistive past adhered to the substrate in the …

Go to article

Electroless Metal Adhesion To Organic Dielectric Material With Phase Separated Morphology, Ravi F. Saraf May 1994

Electroless Metal Adhesion To Organic Dielectric Material With Phase Separated Morphology, Ravi F. Saraf

Department of Chemical and Biomolecular Engineering: Patents

Improved adhesion of electroless metal deposited on an organic dielectric layer with phase separated morphology is accomplished by the spontaneous formation of a morphologically and topographically rough surface. In one embodiment a ternary solution of a polar solvent and two polymer precursors of the same polymer which are separable in two phases of different order are cast in film on a substrate and heated to form two phases of different order to spontaneously produce a rough surface. Upon exposure to an alkaline solution, one phase is etched at a faster rate than the other. Seeding and electroless deposition of a …

Go to article

Effect Of Culture Conditions, Donor Age, And Injection Site On In Vitro Development Of Dna Microinjected Porcine Zygotes, M A. Hajdu, J W. Knight, R S. Cansecot, R L. Krisher, William H. Velander, R E. Pearson, F C. Gwazdauskas May 1994

Effect Of Culture Conditions, Donor Age, And Injection Site On In Vitro Development Of Dna Microinjected Porcine Zygotes, M A. Hajdu, J W. Knight, R S. Cansecot, R L. Krisher, William H. Velander, R E. Pearson, F C. Gwazdauskas

Papers in Biotechnology

A series of experiments evaluated development of porcine zygotes microinjected with DNA in three culture media and two incubation temperatures, from postpubertal and prepubertal donors, and between zygotes injected with DNA into the pronucleus and the cytoplasm. Zygotes recovered from 36 postpubertal gilts in Exp. 1 were injected and cultured in modified NCSU-23, modified NCSU-37, and CZB media at 37°C or 39°C for 7 d. In Exp. 2, zygotes were collected from postpubertal or prepubertal gilts, microinjected with DNA, and cultured in modified NCSU-23. In Exp. 3 superovulated prepubertal gilts had DNA injected into the cytoplasm or pronucleus of zygotes. …

Go to article

First Shell Substitution Effects: Diglyeidyl Ether Of Bisphenol A Cured With 4,4'-Diaminodiphenylmethane, Hossein Noureddini, Delmar C. Timm Apr 1994

First Shell Substitution Effects: Diglyeidyl Ether Of Bisphenol A Cured With 4,4'-Diaminodiphenylmethane, Hossein Noureddini, Delmar C. Timm

Papers in Molecular Chemistry

First shell substitution effects were incorporated into a kinetic reaction model descriptive of the polymerization of an epoxy resin formulated from diglycidyl ether of bisphenol A and 4,4'-diaminodiphenylmethane. Analysis of populaiion density distribution dynamics for the hardener and several oligomers in the sol fraction showed that the reactivity of secondary amino hydrogens is less than the reactivity of primary amino hydrogens.

Go to article

Effects Of Time Of Deoxyribonucleic Acid Microinjection On Gene Detection And In Vitro Development Of Bovine Embryos, A.E T. Sparks, R S. Canseco, C G. Russell, J L. Johnson, H D. Moll, William H. Velander, Francis C. Gwazdauskas Mar 1994

Effects Of Time Of Deoxyribonucleic Acid Microinjection On Gene Detection And In Vitro Development Of Bovine Embryos, A.E T. Sparks, R S. Canseco, C G. Russell, J L. Johnson, H D. Moll, William H. Velander, Francis C. Gwazdauskas

Papers in Biotechnology

In vivo fertilized embryos were surgically collected from superovulated dairy cows to evaluate microinjection on embryo development and utilized the polymerase chain reaction technique for selection of transgenic embryos. Seventy-two percent of the embryos with visible pronuclei or nuclei were microinjected with DNA, and the remaining 28% served as uninjected controls. All embryos were cocultured with bovine oviductal epithelial cells. Mean final development scores of embryos within the same initial cell stage at collection were unaffected by microinjection. After 144 h of culture, 45% of the microinjected embryos developed to the morula or blastocyst stage. The transgene was detected in …

Go to article

Reaction Kinetics Analyses Of Amine-Cured Epoxies: First Shell Substitution Effects, Hossein Noureddini, C Q. Zhang, Delmar C. Timm Mar 1994

Reaction Kinetics Analyses Of Amine-Cured Epoxies: First Shell Substitution Effects, Hossein Noureddini, C Q. Zhang, Delmar C. Timm

Papers in Reaction Kinetics

Kinetic reaction theory was used to model first shell substitution effects for several amine-cured epoxy resins, subject to the constraint of intermolecular reactions. Moment analysis will allow numerical simulations to be extended beyond the gel point. Functionalities for several chemical moieties were correlated as a function of conversion. Simulations also incorporated population density distribution dynamics. Analyses of several oligomers clearly demonstrated the dependency of oligomeric weight fractions on first shell substitution effects and conversion. The ratio of rate constants for reactions of secondary amino hydrogens relative to reactions of primary amino hydrogens ranged from 0.5 to 1.2 for the resins …

Go to article

Morphological Composite Materials Formed From Different Precursors, Ravi F. Saraf Feb 1994

Morphological Composite Materials Formed From Different Precursors, Ravi F. Saraf

Department of Chemical and Biomolecular Engineering: Patents

A method of producing a multiphase polymer is disclosed whereby the phases have the same chemical structure but have different morphological states and thus different properties. This is achieved by forming a mixture of precursors of the polymer, at least one of the precursors having a reaction rate higher than the other precursor or precursors in the mixture. The precursor having the highest reaction rate is then converted to obtain a composite of a polymer and the precursors that are not polymerized. This mixture might also be formed by mixing a soluble polymer with its precursor. The polymer/precursor composite is …

Go to article

Reaction Kinetics Analysis Of Urethane Polymerization To Gelation, B Liu, Hossein Noureddini, J S. Dorsey, Delmar C. Timm May 1993

Reaction Kinetics Analysis Of Urethane Polymerization To Gelation, B Liu, Hossein Noureddini, J S. Dorsey, Delmar C. Timm

Papers in Molecular Chemistry

A chemical reaction analysis of a thermosetting, urethane resin formulated from a triol and a diisocyanate is reported. Population density distributions of oligomeric molecules, monomer concentration, the cumulative molar concentration of intramolecular bonds, the resin's average molecular weights, and extent of reaction were determined as a function of time. Rate expressions for intermolecular reactions were first order with respect to the concentration of each reactant and were proportional to the functionality of their respective chemical moieties. Rate expressions for intramolecular reactions were first order with respect to the concentration of the reactant and were proportional to the functionality of the …

Go to article

High-Level Expression Of A Heterologous Protein In The Milk Of Transgenic Swine Using The Cdna Encoding Human Protein C, William H. Velander, John L. Johnson, Raymond L. Page, Chritopher G. Russell, Anuradha Subramanian, Tracy D. Wilkins, Francis C. Gwazdauskas, Christoph Pittus, William N. Drohan Dec 1992

High-Level Expression Of A Heterologous Protein In The Milk Of Transgenic Swine Using The Cdna Encoding Human Protein C, William H. Velander, John L. Johnson, Raymond L. Page, Chritopher G. Russell, Anuradha Subramanian, Tracy D. Wilkins, Francis C. Gwazdauskas, Christoph Pittus, William N. Drohan

Papers in Biotechnology

Transgenic pigs were generated that produced human protein C in their milk at up to 1 g/liter. The gene construct was a fusion gene consisting of the cDNA for human protein C inserted into the first exon of the mouse whey acidic protein gene. These results demonstrate that the mouse whey acidic protein gene contains regulatory elements that can direct cDNA expression at high levels in the pig mammary gland. Recombinant human protein C that was produced at about 380 pg/ml per hr in transgenic pig milk possessed anticoagulant activity that was equivalent to that of protein C derived from …

Go to article

Modeling Of A-Si : H Deposition In A Dc Glow Discharge Reactor, Dariusz Orlicki, Vladimir Hlavacek, Hendrik J. Viljoen Aug 1992

Modeling Of A-Si : H Deposition In A Dc Glow Discharge Reactor, Dariusz Orlicki, Vladimir Hlavacek, Hendrik J. Viljoen

Papers in Reaction Kinetics

PECVD reactors are increasingly used for the manufacturing of electronic components. This paper presents a reactor model for the deposition of amorphous hydrogenated silicon in a dc glow discharge of Ar-SiH4 The parallel-plate configuration is used in this study. Electron and positive ion densities have been calculated in a self-consistent way. A macroscopic description that is based on the Boltzmann equation with forwardscattering is used to calculate the ionization rate. The dissociation rate constant of SiH4 requires knowledge about the electron energy distribution function. Maxwell and Druyvesteyn distributions are compared and the numerical results show that the deposition …

Go to article

In Vitro Development Of Zygotes From Prepubertal Gilts After Microinjection Of Dna, B. L. Williams, J. L. Johnson, A. E.T. Sparks, R. S. Canseco, J. W. Knight, William H. Velander, R. L. Page, W. N. Drohan, J. M. Young, R. E. Pearson, T. D. Wilkins, F. C. Gwazdauskas Jul 1992

In Vitro Development Of Zygotes From Prepubertal Gilts After Microinjection Of Dna, B. L. Williams, J. L. Johnson, A. E.T. Sparks, R. S. Canseco, J. W. Knight, William H. Velander, R. L. Page, W. N. Drohan, J. M. Young, R. E. Pearson, T. D. Wilkins, F. C. Gwazdauskas

Papers in Biotechnology

The effect of pronuclear microinjection of DNA and culture in excised mouse oviducts on the development of porcine zygotes was assessed in this study. Precocious ovulation was induced in prepubertal gilts with pregnant mare's serum gonadotrophin and hCG. Zygotes received either pronuclear microinjection of buffer alone, buffer containing a DNA construct, or no microinjection. Zygotes were cultured in vitro in either modified Krebs-Ringer bicarbonate medium (KRBI for 144 h or in mouse oviduct (MO) explant culture with KRB for 48, 72, 96, or 120 h. Pronuclear microinjection of DNA resulted in a lower (P < .05) cleavage index (CII than did buffer or no microinjection (CI 2.16 k .10 vs 2.80 f .13 and 2.93 f .lo). The CI loss was greatest for DNA-injected zygotes at the two-cell stage of development. Coculture of zygotes in MO resulted in a higher CI (P < .01) than did culture in KRB. Culture in MO for 72 h was the most beneficial system compared with MO for 48, 96, or 120 h (P < .05; CI 3.25 k .12 vs 2.66 k .18, 2.79 f .14, and 2.40 .14, respectively). Microinjection of DNA, not merely the mechanical procedure, was detrimental to early zygote development and may be the cause of low pregnancy rates.

Go to article

Temperature Oscillations Of Alternating-Current-Heated Thin Filaments In Ceramic Fiber Production, Hendrik J. Viljoen, Vladimir Hlavacek Mar 1992

Temperature Oscillations Of Alternating-Current-Heated Thin Filaments In Ceramic Fiber Production, Hendrik J. Viljoen, Vladimir Hlavacek

Papers in Reaction Kinetics

Resistively heated filaments are used to manufacture ceramic fibers. When an ac power source is used for heating, the temperature of the filament oscillates. These oscillations influence the deposition rate on the surface of the filament. An analysis of this problem is presented, and it is also shown that these oscillatory effects diminish as the filament gauge increases. The analysis can help to decide whether an ac or a dc power source should be used.

Go to article

Kinetic Analysis Of Competing Intramolecular And Intermolecular Polymerization Reactions, Hossein Noureddini, Delmar C. Timm Jan 1992

Kinetic Analysis Of Competing Intramolecular And Intermolecular Polymerization Reactions, Hossein Noureddini, Delmar C. Timm

Papers in Molecular Chemistry

ABSTRACT: Kinetic reaction theory was used to model a step-growth, thermoset polymerization of a monomer of even functionality/. Intermolecular additions were represented by second-order and intramolecular reactions were expressed by first-order rate expressions. All functional groups were assumed to react with equal reactivity. Independent variables are degree of polymerization i, extent of cross-linking j, and conversion p. The normalized rate constant for intramolecular reactions is c. The solution for the normalized population density distribution............ subj Formulae for the number-, mass-, and cross-link-average molecular weights were derived.

Go to article

Solder/Polymer Composite Paste And Method, Ravi F. Saraf Nov 1991

Solder/Polymer Composite Paste And Method, Ravi F. Saraf

Department of Chemical and Biomolecular Engineering: Patents

An improved solder/polymer fluxless composite paste interconnection material having a low reflow temperature to form electrical contacts having good bonding strength and low contact resistance. The present pastes comprise a major proportion of a meltable metal alloy powder filler, free of noble metals and preferably free of lead, a minor proportion of a solution of a temperature-stable thermoplastic polymer having a softening temperature above the melting temperature of the metal powder filler in a volatile solvent which evaporates during reflow, and a minor proportion of a fluxing agent having a boiling point lower than the reflow temperature of the composition …

Go to article

Stability Of Poiseuille-Couette Flow Between Concentric Cylinders, J H. Scholtz, Hendrik J. Viljoen, C J. Wright Jan 1990

Stability Of Poiseuille-Couette Flow Between Concentric Cylinders, J H. Scholtz, Hendrik J. Viljoen, C J. Wright

Papers in Fluid Mechanics

The stability of laminar flow between concentric cylinders is analyzed. Conhinrd Poiseuille and Couette flows are considered. It is shown that instabilities exist if the laminar flow is synnetric or near-spaetric on part of the annulus. Instabilities are reported for aspect ratios as small as q = 0.001.

Go to article

Enzyme- Facilitated Transport And Separation Of Organic Acids Through Liquid Membranes, David C. Rethwisch, Anuradha Subramanian, Gao Yi, Jonathan S. Dordick Jan 1990

Enzyme- Facilitated Transport And Separation Of Organic Acids Through Liquid Membranes, David C. Rethwisch, Anuradha Subramanian, Gao Yi, Jonathan S. Dordick

Papers in Biotechnology

The selective separation of organic acids is important for the production of numerous biologially functional rnuleculcs, including amino acids, peptidcs, fats, and pharmaceuticals.' Enzyme, specificalty lipases and proteases, have been used to selectively separate a variety of organic acids; however, multiple steps are usually required,Vn additiun, carbonic anhydrase has been usd in a variety of Eiquid membranes for transport of CO2.) In the present study, we have coupled the selectiviey of enzymes with liquid membranes to provide a single-step method to scicctiveiy separate and purify organic acids.

Go to article

Conformational Changes In An Epitope Localized To The Nh2-Terminal Region Of Protein C, Carolyn L. Orthener, Rapti D. Madurawe, William H. Velander, William N. Drohan, Frances D. Bettey, Dudley K. Strickhand Nov 1989

Conformational Changes In An Epitope Localized To The Nh2-Terminal Region Of Protein C, Carolyn L. Orthener, Rapti D. Madurawe, William H. Velander, William N. Drohan, Frances D. Bettey, Dudley K. Strickhand

Papers in Biotechnology

Murine monoclonal antibodies, developed following immunization with human protein C, were characterized for their ability tboin d antigen in thpe resence of either CaClz or excess EDTA. Three stablec lones were obtained which produced antiboditehsa t bound to protein C only itnh e presence of EDTA. Allt hree antibodies bound to the light choafi np rotein C on immunoblots and also bound to the homologous proteins factor X and prothrombin in solid-phase radioimmunoassays. One antibody, 7D7B10 was purified and studied further. The binding of 7D7B10 to human protein C was characterized bya KOo f 1.4 nM. In competition studies, it …

Go to article

Simultaneous Correlation Of Excess Gibbs Energy And Enthalpy Of Mixing By The Uniquac Equation, Yaşar Demirel, Hatice Gecegörmez Jun 1989

Simultaneous Correlation Of Excess Gibbs Energy And Enthalpy Of Mixing By The Uniquac Equation, Yaşar Demirel, Hatice Gecegörmez

Papers in Analytical Chemistry

Using data for excess Gibbs energy gh and enthalpy of mixing hE, temperature dependent parameters of the UNlQUAC equation have been estimated for twenty four systems of binary mixtures. Fifteen of them include data for gh and hE at more than one isotherm. These parameters are later tested in predicting the gh and hE data simultaneously and representing the effect of temperature on such data. The UNIQUAC equation with temperature dependent parameters represents larger values of maximum heat of mixing than does the UNlQUAC equation with the parameters independent of temperature.

Go to article

First Prev Next Last