Optical immunoassay systems based upon evanescent wave interactions

Journal ArticleImmunoassays based upon evanescent wave interactions are finding increased biosensing application. In these devices, the evanescent tail associated with total internal reflection of an incident beam at the substrate/solution interface provides sensitivity for surface-bound proteins over bulk molecules, allowing homogeneous assays and real-time measurement of binding dynamics. Among such systems are surface plasmon resonance sensors and a resonant mirror device. Several research groups are also developing fluorescent fiberoptic or planar waveguide sensors for biomedical applications. We describe a second-generation planar waveguide fluoroimmunoassay system being developed in our laboratory which uses a molded polystyrene sensor. The 633-nm beam from a laser diode is focused into the 500 Jim-thick planar waveguide by an integral lens. Antibodies to the desired analyte (hCG) are immobilized on the waveguide surface and fluorescence from bound analyte/tracer antibodies in a sandwich format is imaged onto the detector. The geometry of the waveguide allows several zones to be detected, providing the capability for on-sensor calibration. This sensor has shown picomolar sensitivity for the detection of hCG

Bringing an integrative modeling experience to a freshman biomedical engineering course

Journal ArticleAs an integrating lab experience in our Fundamentals of Bioengineering freshman course, we have included a Major Project that ties together many of the principles of biomechanics and bioelectricity covered in the lecture. It uses the human systemic cardiovascular system as a model. During the first half of the semester, students solve finite-difference equations describing the flow of blood in the cardiovascular system using Matlab. During the second half, teams of two students each assemble an electrical circuit analog of the same system. With the models, they make measurements of pressure and flow for both healthy cardiovascular parameters and for several common diseases

Accelerated dual-degree BS/MS program - experience with the first three years

Journal ArticleWe have initiated a pilot program that accelerates the studies of a small group of highly qualified students early in their college careers and allows them to earn both a bachelor's degree and a master's degree in about four years after starting college. It does this by introducing them early to research, taking advantage of their considerable high school AP credit, enrolling them in a closely monitored cohort environment, and asking them to take at least two summers of coursework. Our experiences with the first three years of the program have been positive, with some accomplishments but also challenges

Introduction to biomedical engineering: biomechanics and bioelectricity - part II

LectureIntended as an introduction to the field of biomedical engineering, this book covers the topics of biomechanics (Part I) and bioelectricity (Part II). Each chapter emphasizes a fundamental principle or law, such as Darcy's Law, Poiseuille's Law, Hooke's Law, Starling's Law, levers and work in the area of fluid, solid, and cardiovascular biomechanics. In addition, electrical laws and analysis tools are introduced, including Ohm's Law, Kirchhoff's Laws, Coulomb's Law, capacitors and the fluid/electrical analogy. Culminating the electrical portion are chapters covering Nernst and membrane potentials and Fourier transforms. Examples are solved throughout the book and problems with answers are given at the end of each chapter. A semester-long Major Project that models the human systemic cardiovascular system, utilizing both a Matlab numerical simulation and an electrical analog circuit, ties many of the book's concepts together

Experience with the first three years of an accelerated dual-degree program in biomedical engineering

Journal ArticleOur Department of Bioengineering has instituted a pilot program aimed at helping a select group of highly qualified students obtain both bachelor's and master's degrees in an accelerated timeframe-approximately four years from the beginning of their university studies. A key element of this program is the introduction of the students to research in their second year of studies via a directed and closely supervised cohort mechanism. These students also come to the university with substantial AP credit and spend two summers fulfilling some general education requirements of the university. Our first three years with the program have shown positive results, with most students on track in both academics and research. There have been some challenges, however, with regard to tight scheduling, leaves for religious missions, and continued student stipend funding

Introduction to biomedical engineering: biomechanics and bioelectricity - part I

LectureIntended as an introduction to the field of biomedical engineering, this book covers the topics of biomechanics (Part I) and bioelectricity (Part II). Each chapter emphasizes a fundamental principle or law, such as Darcy's Law, Poiseuille's Law, Hooke's Law, Starling's law, levers and work in the area of fluid, solid, and cardiovascular biomechanics. In addition, electrical laws and analysis tools are introduced, including Ohm's Law, Kirchhoff 's Laws, Coulomb's Law, capacitors and the fluid/electrical analogy. Culminating the electrical portion are chapters covering Nernst and membrane potentials and Fourier transforms. Examples are solved throughout the book and problems with answers are given at the end of each chapter. A semester-long Major Project that models the human systemic cardiovascular system, utilizing both a Matlab numerical simulation and an electrical analog circuit, ties many of the book's concepts together

Plasma-etched polymer waveguides for intrachip optical interconnects

Journal ArticleOptical intrachip communication offers the potential advantages of high speed and lack of electrical interference. We report on progress made on an interconnect design using GaAs LEDs, polymer waveguides, and photodiodes in a silicon substrate. The polymer waveguides are fabricated in polyimide or polystyrene materials, and are patterned by reactive ion etching with a tri-level resist system. The photodiodes are of two designs, including one in which the depletion layer lies directly below the waveguide. The LEDs are fabricated from GaAs deposited by MOCVD on a Ge lattice-matching layer placed between the GaAs and the silicon substrate. Test results are presented for the individual components

PROGRAMMED EFFECTS OF SURFACE WATER PRICE LEVELS ON U.S. AGRICULTURAL WATER USE AND PRODUCTION PATTERNS

Resource /Energy Economics and Policy,