Biology

Use of a two-dimensional ionization chamber array for proton therapy beam quality assurance

Bijan Arjomandy, Narayan Sahoo, Xiaoning Ding, and Michael Gillin
Two-dimensional ion chamber arrays are primarily used for conventional and intensity modulated radiotherapy quality assurance. There is no commercial device of such type available on the market that is offered for proton therapy quality assurance. We have investigated suitability of the MatriXX, a c ... [Med. Phys. 35, 3889 (2008)] published Thu Aug 7, 2008.

[sup 119]Sb---A potent Auger emitter for targeted radionuclide therapy

H. Thisgaard and M. Jensen
Auger electron emitting radionuclides in cancer therapy offer the opportunity to deliver a high radiation dose to the tumor cells with high radiotoxicity while minimizing toxicity to normal tissue. We have in this study identified the Auger emitter Sb as a potent nuclide for targeted radionuclide th ... [Med. Phys. 35, 3839 (2008)] published Thu Aug 7, 2008.

Third-party brachytherapy source calibrations and physicist responsibilities: Report of the AAPM Low Energy Brachytherapy Source Calibration Working Group

Wayne M. Butler, William S. Bice, Jr., Larry A. DeWerd, James M. Hevezi, M. Saiful Huq et al.
The AAPM Low Energy Brachytherapy Source Calibration Working Group was formed to investigate and recommend quality control and quality assurance procedures for brachytherapy sources prior to clinical use. Compiling and clarifying recommendations established by previous AAPM Task Groups 40, 56, and 6 ... [Med. Phys. 35, 3860 (2008)] published Thu Aug 7, 2008.

Tumor tracking and motion compensation with an adaptive tumor tracking system (ATTS): System description and prototype testing

Jurgen Wilbert, Jurgen Meyer, Kurt Baier, Matthias Guckenberger, Christian Herrmann et al.
A novel system for real-time tumor tracking and motion compensation with a robotic HexaPOD treatment couch is described. The approach is based on continuous tracking of the tumor motion in portal images without implanted fiducial markers, using the therapeutic megavoltage beam, and tracking of abdom ... [Med. Phys. 35, 3911 (2008)] published Thu Aug 7, 2008.

TLD assessment of mouse dosimetry during microCT imaging

Said Daibes Figueroa, Christopher T. Winkelmann, William H. Miller, Wynn A. Volkert, and Timothy J. Hoffman
Advances in laboratory animal imaging have provided new resources for noninvasive biomedical research. Among these technologies is microcomputed tomography (microCT) which is widely used to obtain high resolution anatomic images of small animals. Because microCT utilizes ionizing radiation for image ... [Med. Phys. 35, 3866 (2008)] published Thu Aug 7, 2008.

Combining segment generation with direct step-and-shoot optimization in intensity-modulated radiation therapy

Fredrik Carlsson
A method for generating a sequence of intensity-modulated radiation therapy step-and-shoot plans with increasing number of segments is presented. The objectives are to generate high-quality plans with few, large and regular segments, and to make the planning process more intuitive. The proposed meth ... [Med. Phys. 35, 3828 (2008)] published Thu Aug 7, 2008.

An easy-to-use phantom and protocol for weekly PET quality assessment: A multicenter study

M. Vermandel, L. Fin, S. Hapdey, A. Bol, N. Betrouni et al.
The authors have developed a simple phantom and dedicated software for the quality assessment of positron emission tomography (PET) scanners. The phantom is a parallelepiped box filled with a relatively low activity FDG solution and in which simple test objects are placed. Various image quality para ... [Med. Phys. 35, 3922 (2008)] published Thu Aug 7, 2008.

Dosimetric evaluation of a dedicated stereotactic linear accelerator using measurement and Monte Carlo simulation

M. Heydarian, K. Asnaashari, M. Allahverdi, and D. A. Jaffray
Dosimetric parameters of a dedicated stereotactic linear accelerator have been investigated using measurements and Monte Carlo simulations. This linac has a unique built in multileaf collimation (MLC) system with the maximum opening of 16 x 21 cm and 4 mm leaf width at the isocenter and has succes ... [Med. Phys. 35, 3943 (2008)] published Thu Aug 7, 2008.

Air-kerma strength determination of a [sup 169]Yb high dose rate brachytherapy source

J. J. VanDamme, W. S. Culberson, L. A. DeWerd, and J. A. Micka
The increased demand for high dose rate (HDR) brachytherapy as an alternative to external beam radiotherapy has led to the introduction of a HDR brachytherapy isotope Yb. This source offers a dose rate similar to Ir HDR sources, at about one fourth the effective photon energy. This work presents the ... [Med. Phys. 35, 3935 (2008)] published Thu Aug 7, 2008.

Performance evaluation of an improved optical computed tomography polymer gel dosimeter system for 3D dose verification of static and dynamic phantom deliveries

O. Lopatiuk-Tirpak, K. M. Langen, S. L. Meeks, P. A. Kupelian, O. A. Zeidan et al.
The performance of a next-generation optical computed tomography scanner (OCTOPUS-5X) is characterized in the context of three-dimensional gel dosimetry. Large-volume (2.2 L), muscle-equivalent, radiation-sensitive polymer gel dosimeters (BANG-3) were used. Improvements in scanner design leading to ... [Med. Phys. 35, 3847 (2008)] published Thu Aug 7, 2008.

A NTCP approach for estimating the outcome in radioiodine treatment of hyperthyroidism

L. Strigari, R. Sciuto, M. Benassi, S. Bergomi, S. Nocentini et al.
Radioiodine has been in use for over 60 years as a treatment for hyperthyroidism. Major changes in clinical practice have led to accurate dosimetry capable of avoiding the risks of adverse effects and the optimization of the treatment. The aim of this study was to test the capability of a radiobiol ... [Med. Phys. 35, 3903 (2008)] published Thu Aug 7, 2008.

Real-time tumor tracking with preprogrammed dynamic multileaf-collimator motion and adaptive dose-rate regulation

Byong Yong Yi, Sarah Han-Oh, Fritz Lerma, Barry L. Berman, and Cedric Yu
The authors have developed a new method for real-time tumor tracking with dynamic multileaf-collimator (MLC) motion under condition of free breathing. Unlike other previously proposed tumor-tracking methods, their new method uses a preprogrammed dynamic MLC sequence in combination with real-time dos ... [Med. Phys. 35, 3955 (2008)] published Thu Aug 7, 2008.

Shimming with permanent magnets for the x-ray detector in a hybrid x-ray/MR system

Zhifei Wen, Rebecca Fahrig, Scott T. Williams, and Norbert J. Pelc
In this x-ray/MR hybrid system an x-ray flat panel detector is placed under the patient cradle, close to the MR volume of interest (VOI), where the magnetic field strength is ~0.5 T. Immersed in this strong field, several electronic components inside the detector become magnetized and create an add ... [Med. Phys. 35, 3895 (2008)] published Thu Aug 7, 2008.

A real-time dynamic-MLC control algorithm for delivering IMRT to targets undergoing 2D rigid motion in the beam's eye view

Ryan McMahon, Ross Berbeco, Seiko Nishioka, Masayori Ishikawa, and Lech Papiez
An MLC control algorithm for delivering intensity modulated radiation therapy (IMRT) to targets that are undergoing two-dimensional (2D) rigid motion in the beam's eye view (BEV) is presented. The goal of this method is to deliver 3D-derived fluence maps over a moving patient anatomy. Target motion ... [Med. Phys. 35, 3875 (2008)] published Thu Aug 7, 2008.

A survey of approaches for direct parametric image reconstruction in emission tomography

Charalampos Tsoumpas, Federico E. Turkheimer, and Kris Thielemans
The quantitative data obtained by emission tomography are decoded using a number of techniques and methods in sequence to provide physiological information. Conventionally, the data are reconstructed to produce a series of static images. Then, pharmacokinetic modeling techniques are applied, and kin ... [Med. Phys. 35, 3963 (2008)] published Thu Aug 7, 2008.

PET/CT will become standard practice for radiotherapy simulation and planning

Tinsu Pan, Lili Chen, and Colin G. Orton
... [Med. Phys. 35, 3825 (2008)] published Thu Aug 7, 2008.

The Importance of an Objective Assessment to Identify Functional Constraints of Young Skier Athletes

Fulvio Stradijot and Taian de Mello Martins Vieira
In general, athletes and trainers overlook the need for periodical monitoring of functional abilities. Altered abilities may lead to the development of acute and chronic injuries. This study provides evidence supporting the inclusion of functional assessment as an essential branch of a training prog ... [J. ASTM Int. 5, 101372 (2008)] published Thu Aug 7, 2008.

Assessment of Current Continuous Hemofiltration Systems and Development of a Novel Accurate Fluid Management System for Use in Extracorporeal Membrane Oxygenation

Philippe Sucosky, Lakshmi P. Dasi, Matthew L. Paden, James D. Fortenberry, and Ajit P. Yoganathan
Extracorporeal membrane oxygenation (ECMO) with a renal replacement therapy such as continuous venovenous hemofiltration (CVVH) provides life-saving temporary heart and lung, and renal support in pediatric and neonatal intensive care units. However, studies have shown that this approach may be hampe ... [J. Med. Devices 2, 035002 (2008)] published Thu Aug 7, 2008.

Pinpointing connectivity despite hidden nodes within stimulus-driven networks

Duane Q. Nykamp
The effects of hidden nodes can lead to erroneous identification of connections among measured nodes in a network. For example, common input from a hidden node may cause correlations among a pair of measured nodes that could be misinterpreted as arising from a direct connection between the measured ... [Phys. Rev. E 78, 021902 (2008)] published Wed Aug 6, 2008.

Negative lens concept for photoacoustic tomography

Changhui Li, Geng Ku, and Lihong V. Wang
Although a small point ultrasound transducer has a wide acceptance angle, its small active area leads to a high thermal-noise-induced electric voltage in the transducer, thus the sensitivity is low. By contrast, a finite-size flat transducer has high sensitivity, but the acceptance angle is small, w ... [Phys. Rev. E 78, 021901 (2008)] published Wed Aug 6, 2008.

Announcement: A new feature---``Controversial Topics in Nonlinear Science: Is the Normal Heart Rate Chaotic?''

Leon Glass
... [Chaos 18, 030201 (2008)] published Wed Aug 6, 2008.

Synchrotron radiation microdiffraction of ballistic molten wax microdrops

R. Graceffa, M. Burghammer, R. J. Davies, and C. Riekel
Using stroboscopic techniques, diffraction patterns of ballistic paraffin wax microdrops have been observed. The microdrops, generated by a high-temperature ink-jet system, travel through the 1 [mu]m synchrotron radiation beam with a speed of about 1.4 m/s. Diffraction patterns were recorded in fli ... [Rev. Sci. Instrum. 79, 086106 (2008)] published Wed Aug 6, 2008.

Instrument for measuring tooth mobility

J. L. Smith, A. Wolfenden, and K. Zwaaneveld
An instrument and intraoral mounting have been developed to assess the degree of tooth mobility induced by the wearing of cast-metal partial dentures. The instrument utilized linear instrument bearings and a transducer to record voltage changes when a load of 5 N was applied to the mesial surface of ... [Rev. Sci. Instrum. 50, 1645 (2008)] published Wed Aug 6, 2008.

Automated instrumentation for research on the lingual tactile sensory system

Kal M. Telage
Modifications in lingual vibrotactile instrumentation including programmable stimulus control, signal delivery, and data acquisition are presented. A discussion emphasizes advantages of the system for evaluating children and previews recent experimental procedures. ... [Rev. Sci. Instrum. 50, 1296 (2008)] published Wed Aug 6, 2008.

Microprocessor-controlled inhalation system for repeated exposure of animals to aerosols

R. L. Carpenter, F. P. Barr, R. L. Leydig, and R. E. Rajala
A microprocessor-controlled inhalation exposure system (MCIES) has been built to automate aerosol generation and sampling while controlling exposure time for animal toxicity studies. The system has a time resolution of 0.1 s and automatically sequences the exposure events from initiation to teminati ... [Rev. Sci. Instrum. 50, 560 (2008)] published Wed Aug 6, 2008.

Cylindrical crossed-coil NMR limb blood flowmeter

R. E. Halbach, J. H. Battocletti, A. Sances, Jr., R. L. Bowman, and V. Kudravcev
A nuclear magnetic resonance (NMR) flowmeter has been developed for noninvasive measurement of upper extremity blood flow in humans. Flow through major arteries and veins is determined by placing the arm into a 12.5-cm i.d. crossed-coil detector structure, contained in a 0.075 T (750 G) steady detec ... [Rev. Sci. Instrum. 50, 428 (2008)] published Wed Aug 6, 2008.

Ratio of analog pulse height module for fluorescence activated cell sorter

G. E. Johnson, B. P. Dorman, and F. H. Ruddle
We describe a simple and inexpensive circuit for producing output pulses of amplitude proportional to the ratio of analog pulse height (RAPH) inputs. Use of a diode to limit negative output excursions results in simplified design and is found to be suitable for Fluorescence Activated Cell Sorter (FA ... [Rev. Sci. Instrum. 50, 109 (2008)] published Wed Aug 6, 2008.

A proposal for in vitro/GFR molecular erythema action spectrum

Joao A. V. de Souza, Fabiane Lorenzini, and Mara R. Rizzatti
We propose an erythema action spectrum based on experimental molecular measurements named molecular erythema action spectrum or in vitro/GFR, where the acronym GFR represents our research group name, Grupo de Fisica das Radiacoes. The in vitro methodology was developed by using a derma tissue simula ... [J. Appl. Phys. 104, 034701 (2008)] published Wed Aug 6, 2008.

A Handheld Computer as Part of a Portable In Vivo Knee Joint Load-Monitoring System

J. A. Szivek, V. S. Nandakumar, C. P. Geffre, and C. P. Townsend
In vivo measurement of loads and pressures acting on articular cartilage in the knee joint during various activities and rehabilitative therapies following focal defect repair will provide a means of designing activities that encourage faster and more complete healing of focal defects. It was the go ... [J. Med. Devices 2, 035001 (2008)] published Wed Aug 6, 2008.

Laser microfabrication of L605 cobalt-chromium cardiovascular stent implants with modulated pulsed Nd:YAG laser

S. K. Sudheer, Devesh Kothwala, S. Prathibha, Chhaya Engineer, Ankur Raval et al.
Photonics modulation techniques can be effectively used for the laser microfabrication of biomedical implants to achieve better flexibility and control of the available optical power. These enable the processing and manufacturing of biomedical implants like cardiovascular stents and micro-metallic c ... [J. Micro/Nanolith. MEMS MOEMS 7, 033012 (2008)] published Tue Aug 5, 2008.

Insect normal hovering flight in ground effect

Tong Gao and Xi-Yun Lu
The ground effect on insect normal hovering is investigated using an immersed boundary-lattice Boltzmann method to solve the two-dimensional incompressible NavierStokes equations. A virtual model of an elliptic foil with oscillating translation and rotation near a body surface or ground is used. Com ... [Phys. Fluids 20, 087101 (2008)] published Tue Aug 5, 2008.

Reversible Oxidation of Spinach Ferredoxin at Surface-Modified Electrodes

Jason Komadina, Stephen Walch, Rainer Fasching, Arthur Grossman, and Fritz B. Prinz
The oxidation of Spinacia oleracea ferredoxin [2Fe-2S] at modified and unmodified gold and indium tin oxide electrodes was studied by cyclic voltammetry. The results are compared to previous reports and, in some cases, with the results of quantum chemical simulations. We found that protonated 4-merc ... [J. Electrochem. Soc. 155, B1008 (2008)] published Tue Aug 5, 2008.

Simulation of vibrational energy transfer in two-dimensional infrared spectroscopy of amide I and amide II modes in solution

Robbert Bloem, Arend G. Dijkstra, Thomas la Cour Jansen, and Jasper Knoester
Population transfer between vibrational eigenstates is important for many phenomena in chemistry. In solution, this transfer is induced by fluctuations in molecular conformation as well as in the surrounding solvent. We develop a joint electrostatic density functional theory map that allows us to co ... [J. Chem. Phys. 129, 055101 (2008)] published Tue Aug 5, 2008.

Photoelectron spectrum of valence anions of uracil and first-principles calculations of excess electron binding energies

Rafal A. Bachorz, Wim Klopper, Maciej Gutowski, Xiang Li, and Kit H. Bowen
The photoelectron spectrum (PES) of the uracil anion is reported and discussed from the perspective of quantum chemical calculations of the vertical detachment energies (VDEs) of the anions of various tautomers of uracil. The PES peak maximum is found at an electron binding energy of 2.4 eV, and the ... [J. Chem. Phys. 129, 054309 (2008)] published Tue Aug 5, 2008.

Morphogenesis of Growing Soft Tissues

Julien Dervaux and Martine Ben Amar
Recently, much attention has been given to a noteworthy property of some soft tissues: their ability to grow. Many attempts have been made to model this behavior in biology, chemistry, and physics. Using the theory of finite elasticity, Rodriguez has postulated a multiplicative decomposition of the ... [Phys. Rev. Lett. 101, 068101 (2008)] published Tue Aug 5, 2008.

Density-fragment interaction approach for quantum-mechanical/molecular-mechanical calculations with application to the excited states of a Mg[sup 2+]-sensitive dye

Kazuhiro Fujimoto and Weitao Yang
A density-fragment interaction (DFI) approach for large-scale calculations is proposed. The DFI scheme describes electron density interaction between many quantum-mechanical (QM) fragments, which overcomes errors in electrostatic interactions with the fixed point-charge description in the convention ... [J. Chem. Phys. 129, 054102 (2008)] published Mon Aug 4, 2008.

Electrical detection of biomaterials using AlGaN/GaN high electron mobility transistors

B. S. Kang, H. T. Wang, F. Ren, and S. J. Pearton
Chemical sensors can be used to analyze a wide variety of environmental and biological gases and liquids and may need to be able to selectively detect a target analyte. Different methods, including gas chromatography, chemiluminescence, selected ion flow tube, and mass spectroscopy, have been used t ... [J. Appl. Phys. 104, 031101 (2008)] published Mon Aug 4, 2008.

Complex dynamics of human red blood cell flickering: Alterations with in vivo aging

Madalena Costa, Ionita Ghiran, C.-K. Peng, Anne Nicholson-Weller, and Ary L. Goldberger
Human red blood cells (RBCs) exhibit vibratory motions, referred to as flickering. Their dynamical properties, classically attributed to thermal mechanisms, have not been fully characterized. Using detrended fluctuation analysis and multiscale entropy methods, we show that the short-term flickering ... [Phys. Rev. E 78, 020901 (2008)] published Fri Aug 1, 2008.

A Potential Elastohydrodynamic Origin of Load-Support and Coulomb-Like Friction in Lung/Chest Wall Lubrication

James P. Butler and Stephen H. Loring
During normal breathing, the mesothelial surfaces of the lung and chest wall slide relative to one another. Experimentally, the shear stresses induced by such reciprocal sliding motion are very small, consistent with hydrodynamic lubrication, and relatively insensitive to sliding velocity, similar t ... [J. Tribol. 130, 041201 (2008)] published Fri Aug 1, 2008.

Enzyme-based lactic acid detection using AlGaN/GaN high electron mobility transistors with ZnO nanorods grown on the gate region

B. H. Chu, B. S. Kang, F. Ren, C. Y. Chang, Y. L. Wang et al.
The detection of lactic acid with ZnO nanorod-gated AlGaN/GaN high electron mobility transistors (HEMTs) was demonstrated. The array of ZnO nanorods provided a large effective surface area with a high surface-to-volume ratio and a favorable environment for the immobilization of lactate oxidase. The ... [Appl. Phys. Lett. 93, 042114 (2008)] published Fri Aug 1, 2008.

Development of a combined K-edge subtraction and fluorescence subtraction imaging system for small animals

Brian Bewer, Honglin Zhang, Ying Zhu, Limei Zhang, Graham N. George et al.
A novel combined imaging system for small animals using dilute concentrations of iodine as a contrast agent was developed for wide and pencil photon beam image acquisitions. This combined imaging system used K-edge subtraction (KES) and fluorescence subtraction imaging (FSI) and was tested at the Ha ... [Rev. Sci. Instrum. 79, 085102 (2008)] published Fri Aug 1, 2008.

Accurate and quick calibration method for polarization-modulation spectroscopy using an ac-modulated polarizing undulator

Masahito Tanaka, Kazutoshi Yagi-Watanabe, Fusae Kaneko, and Kazumichi Nakagawa
An accurate calibration method in which an ac-modulated polarizing undulator is used for polarization modulation spectroscopy such as circular dichroism (CD) and linear dichroism (LD) has been proposed and successfully applied to vacuum ultraviolet (vuv) CD and LD spectra measured at beamline BL-5B ... [Rev. Sci. Instrum. 79, 083102 (2008)] published Fri Aug 1, 2008.

Implementation of a phase array diffuse optical tomographic imager

K. Rajan, V. Vijayakumar, Samir Kumar Biswas, and R. M. Vasu
Diffuse optical tomography (DOT) using near-infrared (NIR) light is a promising tool for noninvasive imaging of deep tissue. This technique is capable of quantitative reconstructions of absorption coefficient inhomogeneities of tissue. The motivation for reconstructing the optical property variation ... [Rev. Sci. Instrum. 79, 084301 (2008)] published Fri Aug 1, 2008.

Maximally Informative Stimuli and Tuning Curves for Sigmoidal Rate-Coding Neurons and Populations

Mark D. McDonnell and Nigel G. Stocks
A general method for deriving maximally informative sigmoidal tuning curves for neural systems with small normalized variability is presented. The optimal tuning curve is a nonlinear function of the cumulative distribution function of the stimulus and depends on the mean-variance relationship of the ... [Phys. Rev. Lett. 101, 058103 (2008)] published Fri Aug 1, 2008.

The physics of embolic stroke. (arXiv:0808.1075v1 [cond-mat.soft])

ePrint arXiv http://arXiv.org/

Power-law scaling in protein synthesis of a stochastic regulon. (arXiv:0808.1076v1 [q-bio.CB])

ePrint arXiv http://arXiv.org/

Asymptotic dynamics of attractive-repulsive swarms. (arXiv:0801.2566v2 [q-bio.PE] UPDATED)

ePrint arXiv http://arXiv.org/

Self-organized periodicity of protein clusters in growing bacteria. (arXiv:0808.0888v1 [cond-mat.stat-mech] CROSS LISTED)

ePrint arXiv http://arXiv.org/