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Depeng Wang, Yuehang Wang, Weiran Wang, Dandan Luo, Upendra Chitgupi, Jumin Geng, Yang Zhou, Lidai Wang, Jonathan F Lovell, Jun Xia
Photoacoustic computed tomography (PACT) holds great promise for biomedical imaging, but wide-spread implementation is impeded by the bulkiness of flash-lamp-pumped laser systems, which typically weigh between 50 - 200 kg, require continuous water cooling, and operate at a low repetition rate. Here, we demonstrate that compact lasers based on emerging diode technologies are well-suited for preclinical and clinical PACT. The diode-pumped laser used in this study had a miniature footprint (13 × 14 × 7 cm(3)), weighed only 1...
January 1, 2017: Biomedical Optics Express
N M Pinkerton, L Behar, K Hadri, B Amouroux, C Mingotaud, D R Talham, S Chassaing, J-D Marty
Ionic Flash NanoPrecipitation (iFNP) was evaluated as a novel method for the synthesis of inorganic-organic hybrid nanomaterials and proved to be remarkably effective, fast and practical. To prove the potential of iFNP, various nanostructured GdPO4-based materials of biomedical imaging relevance were easily prepared in a one-step, tunable and highly controlled manner using only water as solvent.
January 11, 2017: Nanoscale
Lijin Huang, Man He, Bei-Bei Chen, Qian Cheng, Bin Hu
Hydrophilic magnetic N-doped porous carbon composites (MNPCs) with high special surface areas and rich nitrogen content was prepared via simple one-step carbonization of zinc oxide nanoparticles (ZnO NPs), 2-methylimidazole (HmIm) and Fe3O4@SiO2 magnetic nanoparticles (MNPs) mixture directly. During the carbonization process, ZnO NPs directly reacts with HmIm to yield porous ZIF-8 while the MNPs are incorporated into the frameworks to generate magnetic metal-organic frameworks (MFCs), and the MFCs acts as a self-sacrificing template to prepare MNPC...
January 4, 2017: ACS Applied Materials & Interfaces
B Hernandez Reyes, E Rodriguez Perez, M Sosa Aquino
PURPOSE: To implement a back-projection algorithm for 2D dose reconstructions for in vivo dosimetry in radiation therapy using an Electronic Portal Imaging Device (EPID) based on amorphous silicon. METHODS: An EPID system was used to calculate dose-response function, pixel sensitivity map, exponential scatter kernels and beam hardenig correction for the back-projection algorithm. All measurements were done with a 6 MV beam. A 2D dose reconstruction for an irradiated water phantom (30×30×30 cm(3) ) was done to verify the algorithm implementation...
June 2016: Medical Physics
S Patch, M Kireeff Covo, A Jackson, Y Qadadha, K Campbell, R Albright, P Bloemhard, A Donoghue, C Siero, T Gimpel, S Small, B Ninemire, M Johnson, L Phair
PURPOSE: The potential of particle therapy has not yet been fully realized due to inaccuracies in range verification. The purpose of this work was to correlate the Bragg peak location with target structure, by overlaying thermoacoustic localization of the Bragg peak onto an ultrasound image. METHODS: Pulsed delivery of 50 MeV protons was accomplished by a fast chopper installed between the ion source and the inflector of the 88″ cyclotron at Lawrence Berkeley National Lab...
June 2016: Medical Physics
M Reinhart, M F Fast, S Nill, U Oelfke
PURPOSE: Mimicking state-of-the-art patient radiotherapy with high precision irradiators for small animals allows advanced dose-effect studies and radiobiological investigations. One example is the implementation of pre-clinical IMRT-like irradiations, which requires the development of inverse planning for keV photon beams. As a first step, we present a novel kernel-based dose calculation engine for keV x-rays with explicit consideration of energy and material dependencies. METHODS: We follow a superposition-convolution approach adapted to keV x-rays, based on previously published work on micro-beam therapy...
June 2016: Medical Physics
Y M Yang, K Bush, B Han, L Xing
PURPOSE: Accurate and fast dose calculation is a prerequisite of precision radiation therapy in modern photon and particle therapy. While Monte Carlo (MC) dose calculation provides high dosimetric accuracy, the drastically increased computational time hinders its routine use. Deterministic dose calculation methods are fast, but problematic in the presence of tissue density inhomogeneity. We leverage the useful features of deterministic methods and MC to develop a hybrid dose calculation platform with autonomous utilization of MC and deterministic calculation depending on the local geometry, for optimal accuracy and speed...
June 2016: Medical Physics
J Ma, J Son, B Arun, J Hazle, K Hwang, K Wang, E Bayram, J Madewell, W Yang, B Dogan
PURPOSE: To develop and demonstrate a short breast (sb) MRI protocol that acquires both T2-weighted and dynamic contrast-enhanced T1-weighted images in approximately ten minutes. METHODS: The sb-MRI protocol consists of two novel pulse sequences. The first is a flexible fast spin-echo triple-echo Dixon (FTED) sequence for high-resolution fat-suppressed T2-weighted imaging, and the second is a 3D fast dual-echo spoiled gradient sequence (FLEX) for volumetric fat-suppressed T1-weighted imaging before and post contrast agent injection...
June 2016: Medical Physics
W Hsi, G Jiang, Y Sheng
PURPOSE: To study the correlations of the radiation biological equivalent doses (BED) along depth and lateral distance between LEM-1 and MKM approaches. METHODS: In NIRS-MKM (Microdosimetric Kinetic Model) approach, the prescribed BED, referred as C-Eq, doses aims to present the relative biological effectiveness (RBE) for different energies of carbon-ions on a fixed 10% survival value of HCG cell with respect to convention X-ray. Instead of a fixed 10% survival, the BED doses of LEM-1 (Local Effect Model) approach, referred as X-Eq, aims to present the RBE over the whole survival curve of chordoma-like cell with alpha/beta ratio of 2...
June 2016: Medical Physics
B Zhao, T Chiu, X Gu, H Lee, L Nedzi, S Jiang
PURPOSE: 3D printed custom bolus is regularly used in radiation therapy clinic as a compensator. However, usual method of bolus printing with 100% filling is very time-consuming. The purpose of this study is to evaluate the feasibility and benefit of 3D printed bolus filled with UR. METHODS: Two boluses were designed on nose (9e electrons) and ear (6× photons) for a head phantom in treatment planning system (TPS) to achieve dose coverage to the skin. The bolus structures (56-167cc) were converted to STereoLithographic (STL) model using an in-house developed algorithm and sent to a commercial fused deposition modeling (FDM) printer...
June 2016: Medical Physics
J Andreozzi, K Mooney, P Bruza, A Curcuru, S Saunders, D Gladstone, B Pogue, O Green
PURPOSE: To investigate the viability of using Cherenkov imaging as a fast and robust method for quality assurance tests in the presence of a magnetic field, where other instruments can be limited. METHODS: Water tank measurements were acquired from a clinically utilized adaptive magnetic resonance image guided radiation therapy (MR-IGRT) machine with three multileaf-collimator equipped 60Co sources. Cherenkov imaging used an intensified charge coupled device (ICCD) camera placed 3...
June 2016: Medical Physics
T Song, Y Li, L Zhou
PURPOSE: To develop a fast Monte Carlo dose calculation algorithm for Gamma Knife. METHODS: To make the simulation more efficient, we implemented the track repeating technique on GPU. We first use EGSnrc to pre-calculate the photon and secondary electron tracks in water from two mono-energy photons of 60Co. The total photon mean free paths for different materials and energies are obtained from NIST. During simulation, each entire photon track was first loaded to shared memory for each block, the incident original photon was then splitted to Nthread sub-photons, each thread transport one sub-photon, the Russian roulette technique was applied for scattered and bremsstrahlung photons...
June 2016: Medical Physics
David D Waters, S Matthijs Boekholdt
Since 2014, guidelines for the management of lipid disorders to reduce cardiovascular (CV) events have been updated in the United States, the United Kingdom, Europe, and Canada. Some of these guidelines are almost entirely evidence-based whereas others are a mix of evidence and expert opinion. Guidelines differ on such simple questions as to whether blood samples should be fasting or nonfasting, and whether low-density lipoprotein cholesterol (LDL-C) or another lipid parameter should be the primary focus of treatment...
October 24, 2016: Canadian Journal of Cardiology
Xin Wang, Zhen Wen, Hengyu Guo, Changsheng Wu, Xu He, Long Lin, Xia Cao, Zhong Lin Wang
Ocean energy, in theory, is an enormous clean and renewable energy resource that can generate electric power much more than that required to power the entire globe without adding any pollution to the atmosphere. However, owing to a lack of effective technology, such blue energy is almost unexplored to meet the energy requirement of human society. In this work, a fully packaged hybrid nanogenerator consisting of a rolling triboelectric nanogenerator (R-TENG) and an electromagnetic generator (EMG) is developed to harvest water motion energy...
December 27, 2016: ACS Nano
Prerna Chand, Takahiro Kamiya
The genus Xestoleberis has a global distribution, and although they are predominant in shallow marine environments adapted to both sediment and algal habitats, only two species of this genus, Xestoleberis curta (Brady, 1866) and Xestoleberis variegata Brady, 1880, have previously been reported from the Fiji archipelago. Herein we report seven new species of the genus Xestoleberis from intertidal environments of fringing reef flats of the Fiji Islands: Xestoleberis becca n. sp., Xestoleberis concava n. sp., Xestoleberis gracilariaii n...
December 18, 2016: Zootaxa
Farhana Afroz, Amy Lang, Maria Laura Habegger, Philip Motta, Robert Hueter
The Shortfin Mako shark (Isurus oxyrinchus) is a fast swimmer and has incredible turning agility, and has flexible scales known to bristle up to 50° in the flank regions. It is purported that this bristling capability of the scales may result in a unique pass flow control method to control flow separation and reduce drag. It appears that the scales have evolved to be only actuated when the flow over the body is reversed; thereby inducing a method of inhibiting flow reversal close to the surface. In addition, bristled scales form cavities which could induce boundary layer mixing and further assist in delaying flow separation...
December 20, 2016: Bioinspiration & Biomimetics
M S R Fachmann, C Löfström, J Hoorfar, F Hansen, J Christensen, S Mansdal, M H Josefsen
: Salmonella is recognised as one of the most important foodborne bacteria, and has a wide health and socioeconomical impact worldwide. Fresh pork meat is one of the main sources of Salmonella and efficient and fast methods for detection are therefore necessary. Current methods for Salmonella detection in fresh meat usually include >16 h of culture enrichment, in few cases < 12 h, thus requiring at least two working shifts. Here, we report a rapid (< 5 h) and high throughput method, for screening of Salmonella in samples from fresh pork meat, consisting of a 3-h enrichment in standard buffered peptone water, and a real-time PCR compatible sample preparation method, based on filtration, centrifugation, and enzymatic digestion, followed by fast cycling real-time PCR detection...
December 16, 2016: Applied and Environmental Microbiology
Neelam Tyagi, Sandra Fontenla, Jing Zhang, Michelle Cloutier, Mo Kadbi, James Mechalakos, Michael Zelefsky, Joseph Deasy, Margie Hunt
PURPOSE: To evaluate a commercial synthetic CT (syn-CT) software for use in prostate radiotherapy Methods: Twenty-five prostate patients underwent CT and MR simulation scans in treatment position on a 3T MR scanner. A commercially available MR protocol was used that included a T2w turbo spin-echo sequence for soft-tissue contrast and a dual echo 3-D mDIXON fast field echo (FFE) sequence for generating syn-CT. A dual-echo 3-D FFE B0 map was used for patient-induced susceptibility distortion analysis and a new 3-D balanced-FFE sequence was evaluated for identification of implanted gold fiducial markers and subsequent image-guidance during radiotherapy delivery...
December 16, 2016: Physics in Medicine and Biology
Paula Martín-Gómez, Luis Serrano, Juan Pedro Ferrio
In ecohydrology, it is generally assumed that xylem water reflects the water source used by plants. Several studies have reported isotopic enrichment within woody tissues, particularly during dormancy periods or after long periods of inactivity. However, little is known about the short-term dynamics of this process. Here we assessed the magnitude and dynamics of xylem isotopic enrichment in suberized twigs of pines and oaks. We performed a series of laboratory experiments, in which we monitored hourly changes in water content and isotopic composition under two contrasting scenarios of sap flow restriction...
December 14, 2016: Tree Physiology
Yingying Pan, Siwei Shi, Xun Lao, Jinlong Zhang, Shiming Tan, Zirong Wu, Jing Huang
GLP-1 is an incretin hormone that can effectively lower blood glucose, however, the short time of biological activity and the side effect limit its therapeutic application. Many methods have been tried to optimize GLP-1 to extend its in vivo half-time, reduce its side effect and enhance its activity. Here we have chosen the idea to dimerize GLP-1 with a C-terminal lysine to form a new GLP-1 analog, DLG3312. We have explored the structure and the biological property of DLG3312, and the results indicated that DLG3312 not only remained the ability to activate the GLP-1R, but also strongly stimulated Min6 cell to secrete insulin...
December 10, 2016: Peptides
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