Scholars@Duke
Glenn S. Edwards

Glenn S. Edwards

Professor Emeritus of Physics
Physics
GEdwards@phy.duke.edu
Box 90305, Durham, NC 27708-0305
French Family Science Center, 2314, Durham, NC 27708

Selected Publications

Mathematical models of dorsal closure.

Journal Article Progress in biophysics and molecular biology · September 2018 Dorsal closure is a model cell sheet movement that occurs midway through Drosophila embryogenesis. A dorsal hole, filled with amnioserosa, closes through the dorsalward elongation of lateral epidermal cell sheets. Closure requires contributions from 5 dist ... Full text Cite

Unified biophysical mechanism for cell-shape oscillations and cell ingression.

Journal Article Physical review. E · June 2018 We describe a mechanochemical and percolation cascade that augments myosin's regulatory network to tune cytoskeletal forces. Actomyosin forces collectively generate cytoskeletal forces during cell oscillations and ingression, which we quantify by elastic p ... Full text Cite

Cell Sheet Morphogenesis: Dorsal Closure in Drosophila melanogaster as a Model System.

Journal Article Annual review of cell and developmental biology · October 2017 Dorsal closure is a key process during Drosophila morphogenesis that models cell sheet movements in chordates, including neural tube closure, palate formation, and wound healing. Closure occurs midway through embryogenesis and entails circumferential elong ... Full text Cite

Quantifying dorsal closure in three dimensions.

Journal Article Molecular biology of the cell · December 2016 Dorsal closure is an essential stage of Drosophila embryogenesis and is a powerful model system for morphogenesis, wound healing, and tissue biomechanics. During closure, two flanks of lateral epidermis close an eye-shaped dorsal opening that is filled wit ... Full text Cite

Remodeling Tissue Interfaces and the Thermodynamics of Zipping during Dorsal Closure in Drosophila.

Journal Article Biophysical journal · December 2015 Dorsal closure during Drosophila embryogenesis is an important model system for investigating the biomechanics of morphogenesis. During closure, two flanks of lateral epidermis (with actomyosin-rich purse strings near each leading edge) close an eye-shaped ... Full text Cite

Complete canthi removal reveals that forces from the amnioserosa alone are sufficient to drive dorsal closure in Drosophila.

Journal Article Molecular biology of the cell · November 2014 Drosophila's dorsal closure provides an excellent model system with which to analyze biomechanical processes during morphogenesis. During native closure, the amnioserosa, flanked by two lateral epidermal sheets, forms an eye-shaped opening with canthi at e ... Full text Cite

Cell ingression and apical shape oscillations during dorsal closure in Drosophila.

Journal Article Biophysical journal · March 2012 Programmed patterns of gene expression, cell-cell signaling, and cellular forces cause morphogenic movements during dorsal closure. We investigated the apical cell-shape changes that characterize amnioserosa cells during dorsal closure in Drosophila embryo ... Full text Cite

Drosophila morphogenesis: tissue force laws and the modeling of dorsal closure.

Journal Article HFSP journal · December 2009 Dorsal closure, a stage of Drosophila development, is a model system for cell sheet morphogenesis and wound healing. During closure, two flanks of epidermal tissue progressively advance to reduce the area of the eye-shaped opening in the dorsal surface, wh ... Full text Cite

Mechanisms for soft-tissue ablation and the development of alternative medical lasers based on investigations with mid-infrared free-electron lasers

Journal Article Laser and Photonics Reviews · November 5, 2009 Experimental evidence indicating the potential biomedical advantages of using a Mark-III Free-Electron Laser (FEL) for the ablation of soft tissue were first reported in 1994. Research progress since that time is reviewed, including: 1) successful human su ... Full text Cite

Thermal vapor bubble and pressure dynamics during infrared laser ablation of tissue

Journal Article Applied Physics Letters · January 19, 2009 Free-electron laser irradiation can superheat tissue water, driving thermal vapor bubbles confined by tissue matrix and leading to mechanical tissue failure (ablation). Acoustic transients propagating from an ablation cavity were recorded with a polarizati ... Full text Cite

Neuromelanins isolated from different regions of the human brain exhibit a common surface photoionization threshold.

Journal Article Photochemistry and photobiology · January 2009 Neuromelanin isolated from the premotor cortex, cerebellum, putamen, globus pallidus and corpus callosum of the human brain is studied by scanning probe and photoelectron emission microscopies and the results are compared with previously published work on ... Full text Cite

Drosophila Morphogenesis: Tissue Force Laws and the Modeling of Dorsal Closure

Journal Article Human Frontier Science Program Journal · 2009 Cite

Apoptotic force and tissue dynamics during Drosophila embryogenesis.

Journal Article Science (New York, N.Y.) · September 2008 Understanding cell morphogenesis during metazoan development requires knowledge of how cells and the extracellular matrix produce and respond to forces. We investigated how apoptosis, which remodels tissue by eliminating supernumerary cells, also contribut ... Full text Cite

Actomyosin purse strings: renewable resources that make morphogenesis robust and resilient.

Journal Article HFSP journal · August 2008 Dorsal closure in Drosophila is a model system for cell sheet morphogenesis and wound healing. During closure two sheets of lateral epidermis move dorsally to close over the amnioserosa and form a continuous epidermis. Forces from the amnioserosa and actom ... Full text Cite

Pressure (mechanical) effects in infrared tissue ablation

Journal Article Progress in Biomedical Optics and Imaging - Proceedings of SPIE · April 21, 2008 We experimentally demonstrate that the acoustic transients propagating as a result Free-Electron Laser (FEL) ablation in brain tissue exhibit a strong FEL wavelength dependence. These acoustic transients were measured with a time-resolved, polarization qua ... Full text Cite

Emergent properties during dorsal closure in Drosophila morphogenesis.

Journal Article Physical biology · April 2008 Dorsal closure is an essential stage of Drosophila development that is a model system for research in morphogenesis and biological physics. Dorsal closure involves an orchestrated interplay between gene expression and cell activities that produce shape cha ... Full text Cite

6450 nm wavelength tissue ablation using a nanosecond laser based on difference frequency mixing and stimulated Raman scattering.

Journal Article Opt Lett · June 1, 2007 A four-stage laser system was developed, emitting at a wavelength of 6450 nm with a 3-5 ns pulse duration, < or = 2 mJ pulse energy, and 1/2 Hz pulse repetition rate. The laser system successfully ablated rat brain tissue, where both the collateral damage ... Full text Link to item Cite

The surface oxidation potential of melanosomes measured by free electron laser-photoelectron emission microscopy.

Journal Article Photochemistry and photobiology · May 2007 A technique for measuring the photoionization spectrum and the photoelectron emission threshold of a microscopic structured material is presented. The theoretical underpinning of the experiment and the accuracy of the measurements are discussed. The techni ... Full text Cite

Upregulation of forces and morphogenic asymmetries in dorsal closure during Drosophila development.

Journal Article Biophysical journal · April 2007 Tissue dynamics during dorsal closure, a stage of Drosophila development, provide a model system for cell sheet morphogenesis and wound healing. Dorsal closure is characterized by complex cell sheet movements, driven by multiple tissue specific forces, whi ... Full text Cite

Commissioning of S-band RF gun and linac for the mark-III FEL facility at Duke University

Journal Article 28th International Free Electron Laser Conference, FEL 2006 · December 1, 2006 At the Free Electron Laser (FEL) Laboratory of Duke University, there is an S-band linac based Mark III FEL facility which can supply coherent FEL photon in the infrared wavelength range. To supply high quality electron beams and to have excellent pulse st ... Cite

The mark-III FEL facility at duke university

Journal Article 23rd International Linear Accelerator Conference, LINAC 2006 - Proceedings · December 1, 2006 At the Free Electron Laser (FEL) Laboratory of Duke University, there is an S-band linac based Mark III FEL facility which can supply coherent FEL photon in the infrared wavelength range. To supply high quality electron beams and to have excellent pulse st ... Cite

Ultraviolet Laser Microbeam for Dissection of Drosophila Embryos

Journal Article · December 1, 2006 This chapter describes the use of ultraviolet (UV) laser microbeam interrogation strategies, combined with confocal microscopy, to investigate the developmental process of dorsal closure. Drosophila embryos that carry GFP-fusion transgenes are mounted to a ... Full text Cite

Age-dependent photoionization thresholds of melanosomes and lipofuscin isolated from human retinal pigment epithelium cells.

Journal Article Photochemistry and photobiology · November 2006 Melanosomes and lipofuscin were isolated from 14-, 59-, and 76-year-old, human retinal pigment epithelium specimens and examined. The morphological features of these samples were studied by scanning electron microscopy and atomic force microscopy, and the ... Full text Cite

The surface oxidation potential of human neuromelanin reveals a spherical architecture with a pheomelanin core and a eumelanin surface.

Journal Article Proceedings of the National Academy of Sciences of the United States of America · October 2006 Neuromelanin (NM) isolated from the substantia nigra region of the human brain was studied by scanning probe and photoelectron emission microscopies. Atomic force microscopy reveals that NM granules are comprised of spherical structures with a diameter of ... Full text Cite

Photoionization thresholds of melanins obtained from free electron laser-photoelectron emission microscopy, femtosecond transient absorption spectroscopy and electron paramagnetic resonance measurements of oxygen photoconsumption.

Journal Article Photochemistry and photobiology · May 2006 Free electron laser-photoelectron emission microscopy (FEL-PEEM), femtosecond absorption spectroscopy and electron paramagnetic resonance (EPR) measurements of oxygen photoconsumption were used to probe the threshold potential for ionization of eumelanosom ... Full text Cite

Ultraviolet laser microbeam for dissection of drosophila embryos

Chapter · November 16, 2005 This chapter describes the use of ultraviolet (UV) laser microbeam interrogation strategies, combined with confocal microscopy, to investigate the developmental process of dorsal closure. Drosophila embryos that carry GFP-fusion transgenes are mounted to a ... Full text Cite

Applications of free-electron lasers to the biological and physical sciences

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · July 21, 2005 Representative examples of applications research based on Free-Electron Lasers are reviewed. Research highlights include: observation of absolute negative conductance in semiconductor superlattices using a terahertz Free-Electron Laser at the University of ... Full text Cite

Applications of Free-Electron Lasers in the Biological and Materials Sciences

Journal Article Invited Review, Photochemistry and Photobiology. · 2005 Cite

Oxidation Potentials of Human Eumelanosomes and Pheomelanosomes

Journal Article Photochemistry and Photobiology · 2005 Cite

Laser-induced alterations of the Infrared light absorption by biological tissues: Radiometric and spectroscopic measurements

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · December 1, 2003 The temperature alterations in the absorption coefficients of water in cartilage and cornea under laser radiation of an IR Free Electron Laser (PEL) were studied for several wavelengths near 2.9 and 6.1 μm water absorption bands using a pulsed photo-therma ... Full text Cite

Advantage of the Mark-III FEL for biophysical research and biomedical applications.

Journal Article Journal of synchrotron radiation · September 2003 Although 6.45 micro m is not the strongest absorption band of biological tissues in the mid-infrared, a Mark-III free-electron laser (FEL) tuned to this wavelength can efficiently ablate tissue while minimizing collateral damage. A model has previously bee ... Full text Cite

Free-electron-laser-based biophysical and biomedical instrumentation

Journal Article Review of Scientific Instruments · July 1, 2003 A survey of biophysical and biomedical applications of free-electron lasers (FEL) was discussed. It was found that the midinfrared SCA FEL and UV FELs based on storage rings were useful for one- and two-color spectroscopic investigations of biophysical pro ... Full text Cite

Temperature alterations of infrared light absorption by cartilage and cornea under free-electron laser radiation.

Journal Article Applied optics · May 2003 Like pure water, the water incorporated into cartilage and cornea tissue shows a pronounced dependence of the absorption coefficient on temperature. Alteration of the temperature by radiation with an IR free-electron laser was studied by use of a pulsed ph ... Full text Cite

Forces for morphogenesis investigated with laser microsurgery and quantitative modeling.

Journal Article Science (New York, N.Y.) · April 2003 We investigated the forces that connect the genetic program of development to morphogenesis in Drosophila. We focused on dorsal closure, a powerful model system for development and wound healing. We found that the bulk of progress toward closure is driven ... Full text Cite

Time-resolved, light scattering measurements of cartilage and cornea denaturation due to free electron laser radiation.

Journal Article Journal of biomedical optics · April 2003 Light scattering is used to monitor the dynamics and energy thresholds of laser-induced structural alterations in biopolymers due to irradiation by a free electron laser (FEL) in the infrared (IR) wavelength range 2.2 to 8.5 microm. Attenuated total reflec ... Full text Cite

FEL-based biophysical and biomedical instrumentation

Journal Article Invited paper, Review of Scientific Instruments · 2003 Cite

Thermal diffusion and chemical kinetics in laminar biomaterial due to heating by a free-electron laser.

Journal Article Physical review. E, Statistical, nonlinear, and soft matter physics · June 2002 We have theoretically investigated the role of thermal diffusion and chemical kinetics as a possible dynamic explanation for the preferential ablative properties of infrared radiation from a free-electron laser (FEL). The model is based on a laminar system ... Full text Cite

Commissioning of a UV/time-resolved-FTIR beamline at the Duke FEL laboratory

Journal Article Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment · May 1, 2002 We describe the commissioning of a novel two-color beamline at the Duke Free Electron Laser Laboratory, designed to perform time-resolved FTIR spectroscopy in a pump-probe scheme with sub-nanosecond resolution to measure dynamical processes with durations ... Full text Cite

Heat diffusion and chemical kinetics in Mark-III FEL tissue ablation

Journal Article Proceedings of SPIE-The International Society for Optical Engineering · January 1, 2002 We present in some detail a theoretical model that provides a dynamical account for the experimentally observed ablative properties of an FEL tuned near 6.45 microns. The model is based on thermal diffusion and chemical kinetics in a system of alternating ... Full text Cite

Erratum: (Commercial and Biomedical Applications of Ultrafast and Free-Electron Lasers (23-24 January 2002))

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2002 Cite

Comparison of OPA and Mark-III FEL for tissue ablation at 6.45 microns

Journal Article Proceedings of SPIE-The International Society for Optical Engineering · January 1, 2002 We have investigated the experimental consequences of two picosecond infrared lasers, both tuned to 6.45 μm and focused on ocular tissue. The exposure conditions were comparable, other than pulse repetition rate, where an optical parametric oscillator/ampl ... Full text Cite

UV/time-resolved FTIR beamline at the Duke FEL Laboratory

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2002 We describe the commissioning of a novel two-color beamline at the Duke Free Electron Laser Laboratory, designed to perform time-resolved FTIR spectroscopy in a pump-probe scheme with sub-nanosecond resolution to measure dynamical processes with durations ... Full text Cite

Status report on the Duke FEL facility

Journal Article Proceedings of the IEEE Particle Accelerator Conference · December 1, 2001 At the Duke Free Electron Laser (FEL) Laboratory, there are two FEL machines: the Mark III infrared FEL and the OK-4/Storage Ring, which produces UV and XUV laser beam as well as gamma rays via Compton backscattering. The recent status of Mark-III machine ... Cite

Status of Mark III FEL

Journal Article Proceedings of the IEEE Particle Accelerator Conference · December 1, 2001 Status of Mark III free electron laser and its upgrades were presented. An old high voltage source utilizing unregulated rectifier was replaced with power supplies manufactured by Maxwell to reduce optical power fluctuations. To implement faster change of ... Cite

Hollow-glass waveguide delivery of an infrared free-electron laser for microsurgical applications.

Journal Article Applied optics · February 2001 The purpose of this research is to deliver free-electron-laser (FEL) pulses for intraocular microsurgery. The FEL at Vanderbilt University is tunable from 1.8 to 10.8 microm. To deliver the FEL beam we used a metallic-coated hollow-glass waveguide of 530-m ... Full text Cite

Free-electron laser etching of dental enamel

Journal Article Journal of Dentistry · 2001 Cite

Alterations of absorption coefficients of tissue water as a result of the heating under the IR FEL radiation with different wavelengths

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2000 The effect of temperature dependent shift of water absorption band, known for pure water, has been examined, for the first time, for tissue water, using the IR Free Electron Laser radiation. Cooling kinetics of cartilage and cornea irradiated was measured ... Cite

Light source capabilities and applications research at the Duke FEL laboratory

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2000 The Duke FEL Laboratory is a national and international users facility. We describe the current light source capabilities in the infrared, visible, ultraviolet, and Gamma rays. Plans are summarized for the development of two novel beamlines, one for UV-res ... Cite

Fourier transform infrared picosecond time-resolved spectroscopy with a UV free electron laser pump and synchrotron IR probe

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · December 1, 1999 The development of the capability for sub-nanosecond time-resolved infrared spectroscopy, combining the broad spectral bandwidth and other well-established advantages of Fourier transform interferometry with the high power, high repetition rate and wide tu ... Cite

Time-resolved infrared transmittance and reflectance of a propagating melt in gaas

Journal Article Physical Review B - Condensed Matter and Materials Physics · January 1, 1999 The time-resolved infrared transmittance and reflectance of a melt induced by a 10 nsec optical-laser pulse has been observed in an undoped crystalline GaAs wafer. Picosecond pulsed, 2.86 GHz repetition rate, infrared radiation from a free-electron laser w ... Full text Cite

Effect of wavelength on threshold and kinetics of tissue denaturation under laser radiation

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · January 1, 1999 We consider the denaturation process as an alteration in ordered organization of tissue structure and study the threshold and kinetics of laser-induced denaturation in cartilage and cornea undergoing irradiation from a free electron laser (FEL) in the wave ... Full text Cite

Hollow waveguide delivered infrared free electron laser for microsurgical applications

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · December 1, 1998 The Free Electron Laser (FEL) at Vanderbilt University is tunable from 2 μm to 9 μm in the mid-infrared spectrum, which is capable of controlling predicted laser-tissue interaction by selecting a specific wavelength. However, delivery of this laser into th ... Full text Cite

Infrared dynamics of collagen, microtubules, and water: Biophysical research enabling biomedical FEL applications

Journal Article Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms · September 2, 1998 Experimental evidence is presented for FEL induced photothermal protein chemistry and FEL modulation of microtubule dynamics. These findings are discussed in terms of previous investigations of FEL tissue ablation to explore the importance of the micropuls ... Full text Cite

10. Physical Mechanisms Governing the Ablation of Biological Tissue

Journal Article Experimental Methods in the Physical Sciences · December 1, 1997 Full text Cite

Cultured human cornea healing process after free electron laser ablation

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · December 1, 1997 The purpose of this study is to investigate the healing process in cultured human cornea after infrared Free Electron Laser ablation. Fresh human cadaver cornea was ablated using the Free Electron Laser at the amide II band peak (6.45 micrometers). The cor ... Full text Cite

Analytical Debye-Huckel model for electrostatic potentials around dissolved DNA.

Journal Article Biophysical journal · July 1997 We present an analytical, Green-function-based model for the electric potential of DNA in solution, treating the surrounding solvent with the Debye-Huckel approximation. The partial charge of each atom is accounted for by modeling DNA as linear distributio ... Full text Cite

Healing of cultured human cornea after free electron laser ablation

Journal Article Investigative Ophthalmology \& Visual Science · March 1997 Cite

Investigation of a clinical intraocular microsurgical device using the infrared free electron laser

Journal Article Investigative Ophthalmology \& Visual Science · March 1997 Cite

Dynamics of gelatin ablation due to free-electron-laser irradiation

Journal Article Physical Review E - Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics · January 1, 1997 We have carried out simultaneous, time-dependent measurements of the free-electron-laser (FEL)-induced stress transients and ablation plume in gelatin, which serves as a model system for collagenous tissues. The Mark-III FEL is tunable in the mid-IR (2–10 ... Full text Cite

Representing structural information of helical charge distributions in cylindrical coordinates

Journal Article Physical Review E - Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics · January 1, 1997 Structural information in the local electric field produced by helical charge distributions, such as dissolved DNA, is revealed in a straightforward manner employing cylindrical coordinates. Comparison of structure factors derived in terms of cylindrical a ... Full text Cite

Investigation of a clinical intraocular microsurgical device using the infrared free electron laser

Journal Article Investigative Ophthalmology and Visual Science · 1997 Purpose. The Free Electron Laser (PEL) has a wavelength tunability range between 2 and 9 m in the mid-infrared spectrum. It is capable of producing controlled predictable laser-tissue interactions by selecting specific wavelengths. However, delivery of thi ... Cite

Healing of cultured human cornea after free electron laser ablation

Journal Article Investigative Ophthalmology and Visual Science · 1997 Purpose. To study the healing process in cultured human corneas after Qswitched Er:YAG laser ablation. Methods. Fresh human cadaver corneas within were ablated with a Q-switched Er:YAG laser at 2.94 m wavelength. (100ns, 1 Hz) The radiant exposure was 500 ... Cite

Investigation of clinical internal microsurgical device with use of hollow waveguide delivered infrared free electron laser

Journal Article Conference Proceedings - Lasers and Electro-Optics Society Annual Meeting-LEOS · January 1, 1997 An application of hollow waveguide delivered infrared free electron laser (FEL) was investigated. The laser produced macro pulses of 5 μs duration at a repetition rate of 30 Hz. Each macro pulse consisted of a train of 1 ps micropulses repeating at 3 GHz. ... Cite

Free-electron lasers: Reliability, performance, and beam delivery

Journal Article IEEE Journal on Selected Topics in Quantum Electronics · December 1, 1996 The Vanderbilt free-electron laser (FEL) is a continuously tunable source of pulsed, mid-infrared radiation. FEL applications research has been underway for a decade. Recent experimental advances in FEL ablation of soft tissue indicate the potential for FE ... Full text Cite

Infrared free electron laser-tissue interactions with human ocular tissues

Journal Article Investigative Ophthalmology and Visual Science · February 15, 1996 Purpose. To utilize the tuning capability of the Vanderbilt University Free Electron Laser (FEL) to examine ocular laser-tissue interactions with novel infrared wavelengths for potential improvement of ophthalmic laser surgical procedures. Methods. Human c ... Cite

Infrared free electron laser-tissue interactions with human

Journal Article Investigative Ophthalmology \& Visual Science · February 1996 Cite

Midinfrared ablation of dentin with the Vanderbilt FEL

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · January 1, 1996 Absorption spectra of 0.1 - 0.2 mm thick, dehydrated sections of human teeth were measured in the transmission mode with a Bruker FT-IR spectrometer from 2.5 - 20 μm. Absorption peaks for amide I, II and III, carbonate and phosphate were identified. Crater ... Full text Cite

Free Electron Laser (FEL) laser-tissue interaction with human cornea and optic nerve

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · January 1, 1996 A free electron laser (FEL) may be tuned to novel wavelengths to explore laser-tissue interactions for development or improvement of laser surgical procedures. This study investigated the effect of selected infrared wavelengths upon human cornea and optic ... Cite

Biomedical and potential clinical applications for pulsed lasers operating near 6.45 um

Journal Article Optical Engineering · January 1, 1995 The operating parameters of the Vanderbilt free electron laser (FEL) are summarized. Effort are underway to develop compact FELs for medical applications. While further investigations of both the ablation mechanism, in particular the role of the pulse stru ... Full text Cite

Broadband Pockels cell and driver for a Mark III-type free electron laser

Journal Article Review of Scientific Instruments · December 1, 1994 A Pockels cell with an operating range of 2 to 10 μm has been designed, constructed, and tested for use with the Vanderbilt free electron laser. The Pockels cell can be continuously adjusted to switch out from 80 ns to the full 6 μs duration of the FEL mac ... Full text Cite

Low-cost, high-performance array detector for spectroscopy based on a charge-coupled photodiode

Journal Article Review of Scientific Instruments · December 1, 1994 We describe a nitrogen-cooled array detector system based on the Thomson TH 7832A charge-coupled photodiode. Performance comparisons are made between this system and others based on two-dimensional CCDs. The TH 7832A compares favorably in resolution, spect ... Full text Cite

Tissue ablation by a free-electron laser tuned to the amide II band.

Journal Article Nature · September 1994 Efforts to ablate soft tissue with conventional lasers have been limited by collateral damage and by concern over potential photochemical effects. Motivated by the thermal-confinement model, past infrared investigations targeted the OH-stretch mode of wate ... Full text Cite

Partitioning-of-energy model for laser ablation of tissue

Conference Proceedings of SPIE - The International Society for Optical Engineering · August 17, 1994 A theoretical model is presented to account for the experimental observation that infrared tissue ablation is optimized by the use of wavelengths near the amide II band of proteins. The model recognizes the partitioned absorption of IR photons between prot ... Full text Cite

Pulsed JR-FEL applications for the characterization of infrared optical materials

Conference Proceedings of SPIE - The International Society for Optical Engineering · July 27, 1994 Theoretical consideration of thermal lens effect due to linear and nonlinear opiical absorption is presented. Based on this model, Zscan technique, especially two-color Z-scan can be used to detect very low level of unpurities or defects in optical materia ... Full text Cite

Two years of free-electron laser applications research in biological physics

Conference Proceedings of SPIE - The International Society for Optical Engineering · July 27, 1994 The Vanderbilt free-electron laser has been operational for several years. This extended collaboration has been investigating outstanding problems in biological physics and medical physics with several research goals in mind. Our most fundamental goal is t ... Full text Cite

Structural information in the local electric field of dissolved B-DNA

Journal Article Physical Review E · January 1, 1994 We have developed a theoretical model of the electric potential and field for B-DNA in solution to investigate the persistence of structural information in the local field. A Green-function technique is used to account for the phosphate groups, the dominan ... Full text Cite

Structure in the electric potential emanating from DNA

Journal Article Physical Review E · January 1, 1994 We present an analytical model, based on a Green-function technique, for the electric potential surrounding dissolved DNA which treats the full, discrete charge distribution of homopolymer B-DNA and the aqueous solvent as concentric, dielectric cylinders. ... Full text Cite

FEL investigations of energy transfer in condensed phase systems

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · December 1, 1993 The vibrational dynamics of O-H groups in fused silica have been examined by a time-resolved pump-probe technique using the Vanderbilt Free Electron Laser (FEL). We consider two effects, local heating and transient thermal lensing, which can influence meas ... Cite

Biomedical applications of free-electron lasers

Journal Article Optical Engineering · February 1993 Cite

Applications of free-electron lasers to measurements of energy transfer in biopolymers and materials

Conference Proceedings of SPIE - The International Society for Optical Engineering · August 7, 1992 Free-electron lasers (FELs) provide tunable, pulsed radiation in the infrared. Using the FEL as a pump beam, we are investigating the mechanisms for energy transfer between localized vibrational modes and between vibrational modes and lattice or phonon mod ... Full text Cite

Role of counterions in the gigahertz relaxation of wet DNA

Journal Article Physical Review A · January 1, 1992 We have measured the dielectric properties of concentrated solutions and gels (30 mg/ml) of random-sequenced DNA from E. coli in the 400-MHz26-GHz range. Two Debye-type relaxations are evident, one with a relaxation time near 9 ps and attributable to the c ... Full text Cite

Role of immersion refractometry for investigating laser-induced effects in cells.

Journal Article Lasers in surgery and medicine · January 1992 The broad background of scattered light observed in spectra of cell suspensions is reduced by factors of up to 20 by immersion refractometry allowing for improved spectroscopic determination of the absorption properties of cells in the 325-820 nm range. Re ... Full text Cite

The vanderbilt free-electron laser center for biomedical and materials research

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · December 1, 1991 The newly commissioned Vanderbilt Free Electron Laser Center for Biomedical and Materials Research is a multidisciplinary users facility intended as an international resource. It provides extremely intense, continuously tunable, pulsed radiation in the mid ... Full text Cite

Sequence dependence of low-frequency Raman-active modes in nucleic acids

Journal Article Physical Review A · January 1, 1991 We have measured the low-frequency (<200 cm-1) Raman activity of dehydrated fibers and films of polynucleotides and random-sequenced nucleic acids. The spectra exhibit a pronounced, unresolved band in the range 10150 cm-1. A nonlinear least-squares algorit ... Full text Cite

Prediction of modes with dominant base roll and propeller twist in B-DNA poly(dA)-poly(dT)

Journal Article Physical Review A · January 1, 1990 In solving the secular equation of a one-dimensional infinite lattice model of poly(dA)-poly(dT), we obtain dispersion relations. [The notation poly(dA)-poly(dT) means that one strand contains only adenine (A) bases, and the other only thymine (T) bases.] ... Full text Cite

Low-frequency, Raman-active vibrational modes of poly(dA)poly(dT)

Journal Article Physical Review A · January 1, 1989 The Raman activity of low-frequency (20-300 cm-1) vibrational modes of dehydrated, oriented fibers of the sodium salts of poly(dA)poly(dT) and random sequenced DNA have been measured. Distinct bands near 60, 75-100, and 125-140 cm-1 are resolved in poly(dA ... Full text Cite

Vanderbilt University FEL center for biomedical and materials research

Journal Article Nuclear Inst. and Methods in Physics Research, A · January 1, 1988 Full text Cite

Investigation of far-infrared vibrational modes in polynucleotides

Journal Article Physical Review A · January 1, 1987 Far-infrared measurements (40500 cm-1) of vacuum-dried, free-standing, unoriented films of the polynucleotides poly(dA)poly(dT), poly(dA-dT)poly(dA-dT) , and poly(dG)poly(dC) and the ribonucleotide poly(rA)poly(rU) under various salting conditions are repo ... Full text Cite

Direct excitation of internal modes of DNA by microwaves

Journal Article Bioelectrochemistry and Bioenergetics · January 1, 1986 We have been studying the microwave absorption characteristics of various forms of DNA. Our observations have demonstrated that long-chain DNA in saline buffer does not absorb microwaves significantly more than its solvent, but that specific short-length m ... Full text Cite

MICROWAVE-FIELD DRIVEN ACOUSTIC MODES OF DNA.

Journal Article Bioengineering, Proceedings of the Northeast Conference · December 1, 1985 The microwave absorption characteristics of various forms of DNA in the frequency range between 0. 1 and 12 GHz are analyzed. The results are summarized as follows: the microwave absorption of aqueous solutions of long-chain DNA (tens of thousands of base- ... Cite

Microwave-field-driven acoustic modes in DNA.

Journal Article Biophysical journal · June 1985 The direct coupling of a microwave field to selected DNA molecules is demonstrated using standard dielectrometry. The absorption is resonant with a typical lifetime of 300 ps. Such a long lifetime is unexpected for DNA in aqueous solution at room temperatu ... Full text Cite

Correction

Journal Article Physical Review Letters · 1984 Cite

Resonant microwave absorption of selected DNA molecules

Journal Article Physical Review Letters · January 1, 1984 The resonant absorption of microwave energy by aqueous solutions containing DNA of known length is experimentally demonstrated. The resonances observed have relaxation times of hundreds of picoseconds. Absorption by linear and supercoiled circular DNA mole ... Full text Cite

Chain-length-dependent microwave absorption of DNA.

Journal Article Biopolymers · December 1983 Full text Cite