Joseph Andrade - Academia.edu (original) (raw)
Papers by Joseph Andrade
IEEE Engineering in Medicine and Biology Magazine, 2003
Journal of Colloid and Interface Science, Apr 1, 1986
Coated hydroxyethyl methacrylate-sodium sulfoalkyl methacrylate copolymer films were surface char... more Coated hydroxyethyl methacrylate-sodium sulfoalkyl methacrylate copolymer films were surface characterized. The contact angle hysteresis increases and the receding angle decreases with increasing alkyl side-chain length, while the advancing angle decreases with hydration time. It was found that the buoyancy slopes of the advancing (ra) and receding (rr) process determined by the Wilhelmy plate method were not parallel. The ratio of r, to rr was greater than 1, and increases with the alkyl side-chain length and the hydration time, contrary to that of polyhydroxyethyl methacrylate, where rdrr was less than 1. The slope ratio would be suppressed in solution with added salt, revealing that the reorientation and expansion of the polymer chain in water is being suppressed. X-ray photoelectron spectroscopy (XPS) analysis of the surface of these copolymers showed a striking enrichment of the sulfonate groups in the surface. The zeta potential was between-40 and-50 mV as measured by the streaming potential method. During dehydration, along with a decrease in sulfur and sodium concentration in the surface, the carbon 1 s peak at the high binding energy decreased and the alkyl carbon main peak increased. The surface tension of aqueous solutions of sulfoalkyl methacrylate monomers and homopolymers decreases with increasing alkyl side-chain length, which may contribute to the decrease in water-polymer film interfacial tension and thus the increase in the slope ratio.
Journal of macromolecular science, Aug 1, 1973
Division of Materials Science and Engineering and Institute for Biomedical Engineering University... more Division of Materials Science and Engineering and Institute for Biomedical Engineering University of Utah Salt Lake City, Utah 84112 ... Instituto de Quimica Universidad Catdlica de Chile Santiago, Chile ... Division of Materials Science and Engineering and Institute for ...
Clinical Chemistry, Dec 1, 1997
The determination of trace and ultratrace elements in biological fluids, including urine and seru... more The determination of trace and ultratrace elements in biological fluids, including urine and serum, by inductively coupled plasma mass spectrometry (ICP-MS) is discussed. Nonspectral interferences and their corrections by external calibration and calibrator addition are discussed in detail. External calibration with internal calibration and dilution is mostly sufficient to correct for encountered biological matrix effects. For some elements, such as Cs and Zn, the use of calibrator addition provides more accurate results. The importance of spectral interferences and their elimination by isotope selection was also studied. Two examples, Cu and Zn, demonstrate the prime importance of selecting an isotope with minimal polyatomic interferences for analysis. By using 65 Cu and 68 Zn, accurate results for urine and serum can be obtained without excessive pretreatment of samples. Two reference materials, Bio-Rad Lyphochek urine and Kaulson Contox sera, were analyzed. Accuracy was evaluated by comparison with target values, and precision was estimated by the CV within 95% confidence.
한국고분자학회 학술대회 연구논문 초록집, Oct 1, 1989
Journal of Colloid and Interface Science, Jun 1, 1986
Journal of Intelligent Material Systems and Structures, Sep 1, 1994
The "intelligence" of synthetic macromolecules ... more The "intelligence" of synthetic macromolecules is currently a topic of great interest, popularity, and activity. The understanding of macromolecule mechanics and dynamics has reached the stage where unique and novel applications are being developed. Here I present basic principles of polymer surface science, bulk polymer dynamics, and some selected areas in polymer surface dynamics. I include a brief treatment of the complexity of highly dynamic, multi-domain, macromolecular surfaces and their interactions with highly dynamic, multi-domain "block copolymer" proteins which are important in biocompatibility and biotechnology.
Thin Solid Films, Sep 1, 1987
Biological applications of protein films, machines and devices are briefly reviewed. A brief disc... more Biological applications of protein films, machines and devices are briefly reviewed. A brief discussion of protein structure and properties is given. Needs and opportunities in the field include the following: (a) better potential functions to model and predict protein structure, denaturation and adsorption and the assembly of protein films and devices; (b) better methods to characterize protein films, particularly two-dimensional structures and ordering; (c) better means to assemble and stabilize protein machines, such as in lipid or polymer films; (d) means to modify protein stability, binding and enzymatic properties. About 5000 different proteins exist, each "designed" for a specific function: they can serve to stimulate and aid scientists and engineers in the design and development of new generations of molecular machines and devices.
Surface and Interface Analysis, Dec 1, 1986
Polymeric materials generally exhibit various molecular motions and relaxations. Such relaxation ... more Polymeric materials generally exhibit various molecular motions and relaxations. Such relaxation processes, which include the glass transition temperature, have significant effects on physical and mechanical behavior. Polymer molecules and segments at surfaces and interfaces also exhibit motions and relaxations. In air or vacuum, such motions 'permit' the surface to restructure to minimize the surface free energy. In aqueous solution, the polymer surface restructures and reorients to optimally interact with the aqueous solvent, thereby minimizing the interfacial free energy. XPS and related high vacuum techniques probe the vacuum-equilibrated surface. The best way to probe the polymer-liquid interface is via dynamic contact angle or wetting methods. A number of issues and concerns are discussed: (1) the size or hierarchy of structures; (2) the time course of surface dynamic processes; (3) theory, modeling, and simulation of surface dynamics; and (4) experimental methods.
Springer eBooks, 1985
The surface properties of synthetic polymers are important in many industrially significant proce... more The surface properties of synthetic polymers are important in many industrially significant processes and applications. Because of the critical importance of polymer surface properties in many major industries and in technology in general, good textbooks and monographs are readily available, including several focusing on biomedical problems (Table 1).
Springer eBooks, 1985
ABSTRACT This chapter contains sections titled: PrinciplesInstrumentationSpectral Information and... more ABSTRACT This chapter contains sections titled: PrinciplesInstrumentationSpectral Information and Chemical ShiftsQuantification, Depth Profiling, and ImagingThe Auger ParameterApplicationsUltraviolet Photoelectron Spectroscopy (UPS)References
Acs Symposium Series, Jun 1, 1976
This book is intended to provide a fundamental basis for the study of the interaction of polymers... more This book is intended to provide a fundamental basis for the study of the interaction of polymers with living systems, biochemicals, and with aqueous solutions. The surface chemistry and physics of polymeric materials is a subject not normally covered to any significant extent in classical surface chemistry textbooks. Many of the assumptions of classical surface chemistry are invalid when applied to polymer surfaces. Surface properties of polymers are important in the development of medical devices and diagnostic products. Surface properties are also of vital importance in fields such as adhesion, paints and coatings, polymer-filler interactions, heterogeneous catalysis, composites, and polymers for energy generation. The book begins with a chapter considering the current sources of information on polymer surface chemistry and physics. It moves on to consider the question of the dynamics of polymer surfaces and the implica tions of polymer surface dynamics on all subsequent characterization and interfacial studies. Two chapters are directed toward the question of model polymers for preparing model surfaces and interfaces. Complete treatments of X-ray photoelectron spectroscopy and attenuated total reflection infrared spectroscopy are given. There is a detailed treatment of the contact angle with particular emphasis on contact angle hysteresis in aqueous systems, followed by chapters on interfacial electrochemistry and interface acid-base charge-transfer properties. The very difficult problem of block and graft copolymer surfaces is also discussed. The problem of theoretical calculations of surface and interfacial tensions is presented. Raman spectroscopy is considered as an analytical technique for polymer surface characterization."
Biomaterials, 1989
... SURFACE MODIFIED BLOOD COMPATIBLE POLYMERS In vitro blood compatibility of albumin-heparin co... more ... SURFACE MODIFIED BLOOD COMPATIBLE POLYMERS In vitro blood compatibility of albumin-heparin conjugate treated materials. 153 US Hennink, L. Dost, SU Kim, J. Feijen Page 15. IX Studies on the synthesis of non-thrombogenic polymers. ... 337 A. van Berlo VII. ...
Journal of Biomedical Materials Research, Nov 1, 1985
There are four topics related to biomaterials and biocompatibility which I feel are key problems,... more There are four topics related to biomaterials and biocompatibility which I feel are key problems, are often unrecognized, and are therefore rich opportunities for work in the near future : (i) the covalent instability of proteins, (ii) the concept of statistical specificity and statistical heterogeneity, (iii) the issue of solid surface dynamics and surface relaxation, and (iv) the growing concern with the costs of health care and of medical research. Each is briefly discussed in this paper.
A very large number of science and engineering courses taught in colleges and universities today ... more A very large number of science and engineering courses taught in colleges and universities today do not involve laboratories. Although good instructors incorporate class demonstrations, hands on homework, and various teaching aids, including computer simulations, the fact is that students in such courses often accept key concepts and experimental results without discovering them for themselves. The only partial solution to this problem has been increasing use of class demonstrations and computer simulations. The authors feel strongly that many complex concepts can be observed and assimilated through experimentation with properly designed materials. They propose the development of materials and specimens designed specifically for education purposes. Intelligent and communicative materials are ideal for this purpose. Specimens which respond in an observable fashion to new environments and situations provided by the students/experimenter provide a far more effective materials science a...
IEEE Engineering in Medicine and Biology Magazine, 2003
Journal of Colloid and Interface Science, Apr 1, 1986
Coated hydroxyethyl methacrylate-sodium sulfoalkyl methacrylate copolymer films were surface char... more Coated hydroxyethyl methacrylate-sodium sulfoalkyl methacrylate copolymer films were surface characterized. The contact angle hysteresis increases and the receding angle decreases with increasing alkyl side-chain length, while the advancing angle decreases with hydration time. It was found that the buoyancy slopes of the advancing (ra) and receding (rr) process determined by the Wilhelmy plate method were not parallel. The ratio of r, to rr was greater than 1, and increases with the alkyl side-chain length and the hydration time, contrary to that of polyhydroxyethyl methacrylate, where rdrr was less than 1. The slope ratio would be suppressed in solution with added salt, revealing that the reorientation and expansion of the polymer chain in water is being suppressed. X-ray photoelectron spectroscopy (XPS) analysis of the surface of these copolymers showed a striking enrichment of the sulfonate groups in the surface. The zeta potential was between-40 and-50 mV as measured by the streaming potential method. During dehydration, along with a decrease in sulfur and sodium concentration in the surface, the carbon 1 s peak at the high binding energy decreased and the alkyl carbon main peak increased. The surface tension of aqueous solutions of sulfoalkyl methacrylate monomers and homopolymers decreases with increasing alkyl side-chain length, which may contribute to the decrease in water-polymer film interfacial tension and thus the increase in the slope ratio.
Journal of macromolecular science, Aug 1, 1973
Division of Materials Science and Engineering and Institute for Biomedical Engineering University... more Division of Materials Science and Engineering and Institute for Biomedical Engineering University of Utah Salt Lake City, Utah 84112 ... Instituto de Quimica Universidad Catdlica de Chile Santiago, Chile ... Division of Materials Science and Engineering and Institute for ...
Clinical Chemistry, Dec 1, 1997
The determination of trace and ultratrace elements in biological fluids, including urine and seru... more The determination of trace and ultratrace elements in biological fluids, including urine and serum, by inductively coupled plasma mass spectrometry (ICP-MS) is discussed. Nonspectral interferences and their corrections by external calibration and calibrator addition are discussed in detail. External calibration with internal calibration and dilution is mostly sufficient to correct for encountered biological matrix effects. For some elements, such as Cs and Zn, the use of calibrator addition provides more accurate results. The importance of spectral interferences and their elimination by isotope selection was also studied. Two examples, Cu and Zn, demonstrate the prime importance of selecting an isotope with minimal polyatomic interferences for analysis. By using 65 Cu and 68 Zn, accurate results for urine and serum can be obtained without excessive pretreatment of samples. Two reference materials, Bio-Rad Lyphochek urine and Kaulson Contox sera, were analyzed. Accuracy was evaluated by comparison with target values, and precision was estimated by the CV within 95% confidence.
한국고분자학회 학술대회 연구논문 초록집, Oct 1, 1989
Journal of Colloid and Interface Science, Jun 1, 1986
Journal of Intelligent Material Systems and Structures, Sep 1, 1994
The "intelligence" of synthetic macromolecules ... more The "intelligence" of synthetic macromolecules is currently a topic of great interest, popularity, and activity. The understanding of macromolecule mechanics and dynamics has reached the stage where unique and novel applications are being developed. Here I present basic principles of polymer surface science, bulk polymer dynamics, and some selected areas in polymer surface dynamics. I include a brief treatment of the complexity of highly dynamic, multi-domain, macromolecular surfaces and their interactions with highly dynamic, multi-domain "block copolymer" proteins which are important in biocompatibility and biotechnology.
Thin Solid Films, Sep 1, 1987
Biological applications of protein films, machines and devices are briefly reviewed. A brief disc... more Biological applications of protein films, machines and devices are briefly reviewed. A brief discussion of protein structure and properties is given. Needs and opportunities in the field include the following: (a) better potential functions to model and predict protein structure, denaturation and adsorption and the assembly of protein films and devices; (b) better methods to characterize protein films, particularly two-dimensional structures and ordering; (c) better means to assemble and stabilize protein machines, such as in lipid or polymer films; (d) means to modify protein stability, binding and enzymatic properties. About 5000 different proteins exist, each "designed" for a specific function: they can serve to stimulate and aid scientists and engineers in the design and development of new generations of molecular machines and devices.
Surface and Interface Analysis, Dec 1, 1986
Polymeric materials generally exhibit various molecular motions and relaxations. Such relaxation ... more Polymeric materials generally exhibit various molecular motions and relaxations. Such relaxation processes, which include the glass transition temperature, have significant effects on physical and mechanical behavior. Polymer molecules and segments at surfaces and interfaces also exhibit motions and relaxations. In air or vacuum, such motions 'permit' the surface to restructure to minimize the surface free energy. In aqueous solution, the polymer surface restructures and reorients to optimally interact with the aqueous solvent, thereby minimizing the interfacial free energy. XPS and related high vacuum techniques probe the vacuum-equilibrated surface. The best way to probe the polymer-liquid interface is via dynamic contact angle or wetting methods. A number of issues and concerns are discussed: (1) the size or hierarchy of structures; (2) the time course of surface dynamic processes; (3) theory, modeling, and simulation of surface dynamics; and (4) experimental methods.
Springer eBooks, 1985
The surface properties of synthetic polymers are important in many industrially significant proce... more The surface properties of synthetic polymers are important in many industrially significant processes and applications. Because of the critical importance of polymer surface properties in many major industries and in technology in general, good textbooks and monographs are readily available, including several focusing on biomedical problems (Table 1).
Springer eBooks, 1985
ABSTRACT This chapter contains sections titled: PrinciplesInstrumentationSpectral Information and... more ABSTRACT This chapter contains sections titled: PrinciplesInstrumentationSpectral Information and Chemical ShiftsQuantification, Depth Profiling, and ImagingThe Auger ParameterApplicationsUltraviolet Photoelectron Spectroscopy (UPS)References
Acs Symposium Series, Jun 1, 1976
This book is intended to provide a fundamental basis for the study of the interaction of polymers... more This book is intended to provide a fundamental basis for the study of the interaction of polymers with living systems, biochemicals, and with aqueous solutions. The surface chemistry and physics of polymeric materials is a subject not normally covered to any significant extent in classical surface chemistry textbooks. Many of the assumptions of classical surface chemistry are invalid when applied to polymer surfaces. Surface properties of polymers are important in the development of medical devices and diagnostic products. Surface properties are also of vital importance in fields such as adhesion, paints and coatings, polymer-filler interactions, heterogeneous catalysis, composites, and polymers for energy generation. The book begins with a chapter considering the current sources of information on polymer surface chemistry and physics. It moves on to consider the question of the dynamics of polymer surfaces and the implica tions of polymer surface dynamics on all subsequent characterization and interfacial studies. Two chapters are directed toward the question of model polymers for preparing model surfaces and interfaces. Complete treatments of X-ray photoelectron spectroscopy and attenuated total reflection infrared spectroscopy are given. There is a detailed treatment of the contact angle with particular emphasis on contact angle hysteresis in aqueous systems, followed by chapters on interfacial electrochemistry and interface acid-base charge-transfer properties. The very difficult problem of block and graft copolymer surfaces is also discussed. The problem of theoretical calculations of surface and interfacial tensions is presented. Raman spectroscopy is considered as an analytical technique for polymer surface characterization."
Biomaterials, 1989
... SURFACE MODIFIED BLOOD COMPATIBLE POLYMERS In vitro blood compatibility of albumin-heparin co... more ... SURFACE MODIFIED BLOOD COMPATIBLE POLYMERS In vitro blood compatibility of albumin-heparin conjugate treated materials. 153 US Hennink, L. Dost, SU Kim, J. Feijen Page 15. IX Studies on the synthesis of non-thrombogenic polymers. ... 337 A. van Berlo VII. ...
Journal of Biomedical Materials Research, Nov 1, 1985
There are four topics related to biomaterials and biocompatibility which I feel are key problems,... more There are four topics related to biomaterials and biocompatibility which I feel are key problems, are often unrecognized, and are therefore rich opportunities for work in the near future : (i) the covalent instability of proteins, (ii) the concept of statistical specificity and statistical heterogeneity, (iii) the issue of solid surface dynamics and surface relaxation, and (iv) the growing concern with the costs of health care and of medical research. Each is briefly discussed in this paper.
A very large number of science and engineering courses taught in colleges and universities today ... more A very large number of science and engineering courses taught in colleges and universities today do not involve laboratories. Although good instructors incorporate class demonstrations, hands on homework, and various teaching aids, including computer simulations, the fact is that students in such courses often accept key concepts and experimental results without discovering them for themselves. The only partial solution to this problem has been increasing use of class demonstrations and computer simulations. The authors feel strongly that many complex concepts can be observed and assimilated through experimentation with properly designed materials. They propose the development of materials and specimens designed specifically for education purposes. Intelligent and communicative materials are ideal for this purpose. Specimens which respond in an observable fashion to new environments and situations provided by the students/experimenter provide a far more effective materials science a...