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https://www.readbyqxmd.com/read/28102959/x-ray-scatter-correction-for-multi-source-interior-computed-tomography
#1
Hao Gong, Hao Yan, Xun Jia, Bin Li, Ge Wang, Guohua Cao
PURPOSE: The schemes of multi-source interior computed tomography (CT) have shown promise for ultra-fast, organ-oriented, and low-dose dynamic imaging. Besides forward scattering, x-ray cross scattering from multiple x-ray sources activated simultaneously can further degrade image quality. Here, we investigate the overall x-ray scattering artifact in a recently proposed multi-source interior CT architecture, and present two methods for scatter correction. METHODS: Compared to single-source global CT, scattering in multi-source interior CT architecture is affected by two new factors: cross scattering from simultaneously activated multiple x-ray sources and region-of-interest (ROI) oriented interior CT mode...
January 2017: Medical Physics
https://www.readbyqxmd.com/read/28102956/experimental-verification-of-4d-monte-carlo-simulations-of-dose-delivery-to-a-moving-anatomy
#2
Sara Gholampourkashi, Miro Vujicic, Jason Belec, Joanna E Cygler, Emily Heath
PURPOSE: To evaluate a novel 4D Monte Carlo simulation tool by comparing calculations to physical measurements using a respiratory motion phantom. METHODS: We used a dynamic Quasar phantom in both stationary and breathing states (sinusoidal motion of amplitude of 1.8 cm and period of 3.3 s) for dose measurements on an Elekta Agility linear accelerator. Gafchromic EBT3 film and the RADPOS 4D dosimetry system were placed inside the lung insert of the phantom to measure dose profiles and point-dose values at the center of the spherical tumor inside the insert...
January 2017: Medical Physics
https://www.readbyqxmd.com/read/28102953/air-kerma-strength-determination-of-an-hdr-192-ir-source-including-a-geometric-sensitivity-study-of-the-seven-distance-method
#3
Blake R Smith, John A Micka, Manik Aima, Larry A DeWerd, Wesley S Culberson
PURPOSE: To perform an in-air air-kerma strength (SK) calibration of the Bebig model Ir2.A85-2 192Ir high-dose rate (HDR) brachytherapy source manufactured by Mallinckrodt Medical (Westerduinweg, Germany) with the NIST-traceable seven-distance technique established by the University of Wisconsin. A comparison was made between the reference air-kerma rate (RAKR) reported on a certificate from the Physikalisch-Technische Bundesanstalt (Berlin, Germany) (PTB) primary laboratory and the SK determined at the University of Wisconsin Madison Radiation Research Center (UWMRRC)...
January 2017: Medical Physics
https://www.readbyqxmd.com/read/28102695/application-of-modified-atmosphere-packaging-on-aquacultured-fish-and-fish-products-a-review
#4
Achilleas D Bouletis, Ioannis S Arvanitoyannis, Christos Hadjichristodoulou
Aquaculture industry has undergone a rapid and continuous growth during the last decade due to increased demands in seafood consumption and reduced pelagic fish production. Aquaculture sector can provide products with a consistent flow and quality standards to cover the market's needs. Modified atmosphere packaging (MAP) technique has evolved over the last two decades and many reports indicate its beneficial effect on many quality parameters during fish and shellfish preservation. The use of MAP can clearly offer an advantage to the safer distribution of quality aqua cultured fishery products...
January 19, 2017: Critical Reviews in Food Science and Nutrition
https://www.readbyqxmd.com/read/28102524/heat-transfer-capability-of-ethylene-glycol-water-based-nanofluids-containing-graphene-nanoplatelets-design-and-thermophysical-profile
#5
D Cabaleiro, L Colla, S Barison, L Lugo, L Fedele, S Bobbo
This research aims at studying the stability and thermophysical properties of nanofluids designed as dispersions of sulfonic acid-functionalized graphene nanoplatelets in an (ethylene glycol + water) mixture at (10:90)% mass ratio. Nanofluid preparation conditions were defined through a stability analysis based on zeta potential and dynamic light scattering (DLS) measurements. Thermal conductivity, dynamic viscosity, and density were experimentally measured in the temperature range from 283.15 to 343.15 K and nanoparticle mass concentrations of up to 0...
December 2017: Nanoscale Research Letters
https://www.readbyqxmd.com/read/28102178/fast-synthesis-of-ultrathin-zno-nanowires-by-oxidation-of-cu-zn-stacks-in-low-pressure-afterglow
#6
A Altaweel, A Imam, J Ghanbaja, D Mangin, P Miska, T Gries, T Belmonte
The synthesis of ultrathin, single-crystalline zinc oxide nanowires was achieved by treating in a flowing microwave plasma oxidation process, zinc films coated beforehand by a sputtered thin buffer layer of copper. The aspect ratio of the nanowires can be controlled by the following experimental parameters: treatment duration, furnace temperature, oxygen concentration. An average diameter of 6 nm correlated with a mean length of 750 nm can be reached with a fairly high surface number density for very short treatments, typically less than 1 min...
January 19, 2017: Nanotechnology
https://www.readbyqxmd.com/read/28101950/molecular-binding-of-toxic-phenothiazinium-derivatives-azures-to-bovine-serum-albumin-a-comparative-spectroscopic-calorimetric-and-in-silico-study
#7
Somnath Das, Md Maidul Islam, Gopal Chandra Jana, Anirudha Patra, Pradeep K Jha, Maidul Hossain
In this paper, the comparative binding behavior of antimalarial drug azure A, azure B and azure C with bovine serum albumin (BSA) has been studied. The interaction has been confirmed by multispectroscopic (UV, fluorescence, Fourier transform infrared (FT-IR), and circular dichroism) and molecular docking techniques. The experimental results show that azure B has the highest BSA binding affinity followed by azure A and azure C. The experimental evidence of binding showed a static quenching mechanism in the interaction azures with BSA...
January 19, 2017: Journal of Molecular Recognition: JMR
https://www.readbyqxmd.com/read/28101853/investigation-on-the-effects-of-the-formation-of-a-silver-flower-like-structure-on-graphene
#8
Rozalina Zakaria, Siti Fatimah Az Zahra Yusoff, Kok Chung Law, Chin Seong Lim, Harith Ahmad
In this report, we experimentally investigate the formation of "flower-like silver structures" on graphene. Using an electrochemical deposition technique with deposition times of 2.5 and 5 min, agglomerations of silver nanoparticles (AgNPs) were deposited on the graphene surfaces, causing the formation of "flower-like structures" on the graphene substrate. Localized surface plasmon resonance (LSPR) was observed in the interaction between the structures and the graphene substrate. The morphology of the samples was observed using a field-emission scanning electron microscope (FESEM) and Raman spectroscopy...
December 2017: Nanoscale Research Letters
https://www.readbyqxmd.com/read/28101430/projection-method-for-improving-signal-to-noise-ratio-of-localized-surface-plasmon-resonance-biosensors
#9
Ahmed Abumazwed, Wakana Kubo, Chen Shen, Takuo Tanaka, Andrew G Kirk
This paper presents a simple and accurate method (the projection method) to improve the signal to noise ratio of localized surface plasmon resonance (LSPR). The nanostructures presented in the paper can be readily fabricated by nanoimprint lithography. The finite difference time domain method is used to simulate the structures and generate a reference matrix for the method. The results are validated against experimental data and the proposed method is compared against several other recently published signal processing techniques...
January 1, 2017: Biomedical Optics Express
https://www.readbyqxmd.com/read/28101408/in-vivo-visualization-and-ex-vivo-quantification-of-experimental-myocardial-infarction-by-indocyanine-green-fluorescence-imaging
#10
Dmitry Sonin, Garry Papayan, Evgeniia Pochkaeva, Svetlana Chefu, Sarkis Minasian, Dmitry Kurapeev, Jarle Vaage, Nickolay Petrishchev, Michael Galagudza
The fluorophore indocyanine green accumulates in areas of ischemia-reperfusion injury due to an increase in vascular permeability and extravasation of the dye. The aim of the study was to validate an indocyanine green-based technique of in vivo visualization of myocardial infarction. A further aim was to quantify infarct size ex vivo and compare this technique with the standard triphenyltetrazolium chloride staining. Wistar rats were subjected to regional myocardial ischemia (30 minutes) followed by reperfusion (n = 7)...
January 1, 2017: Biomedical Optics Express
https://www.readbyqxmd.com/read/28101272/isolation-and-characterization-of-agrobacterium-strains-from-soil-a-laboratory-capstone-experience
#11
Kim R Finer, Lee Fox, John J Finer
In this investigation, the students' goal was to isolate and characterize Agrobacterium strains from soil. Following selection and enrichment on 1A-t medium, putative Agrobacterium isolates were characterized by Gram stain reaction and biochemical tests. Isolates were further evaluated using polymerase chain reaction (PCR) with different primer sets designed to amplify specific regions of bacterial deoxyribonucleic acid (DNA). Primer sets included AGRH to identify isolates that were members of the Rhizobiaceae, BIOVAR1 primers to identify members of Agrobacterium biovar group I, and a third set, VIRG, to determine presence of virG (only present in pathogenic Agrobacterium strains)...
December 2016: Journal of Microbiology & Biology Education: JMBE
https://www.readbyqxmd.com/read/28100053/the-grateful-infrared-sequential-protein-structural-changes-resolved-by-infrared-difference-spectroscopy
#12
Tilman Kottke, Víctor A Lórenz-Fonfría, Joachim Heberle
The catalytic activity of proteins is a function of structural changes. Very often these are as minute as protonation changes, hydrogen bonding changes, and amino acid side chain reorientations. To resolve these, a methodology is afforded that not only provides the molecular sensitivity but allows for tracing the sequence of these hierarchical reactions at the same time. This feature article showcases results from time-resolved IR spectroscopy on channelrhodopsin (ChR), light-oxygen-voltage (LOV) domain protein, and cryptochrome (CRY)...
January 19, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28098845/optical-tip-clearance-measurements-as-a-tool-for-rotating-disk-characterization
#13
Iker García, Joseba Zubia, Josu Beloki, Jon Arrue, Gaizka Durana, Gotzon Aldabaldetreku
An experimental investigation on the vibrational behavior of a rotating disk by means of three optical fiber sensors is presented. The disk, which is a scale model of the real disk of an aircraft engine, was assembled in a wind tunnel in order to simulate real operation conditions. The pressure difference between the upstream and downstream sides of the disk causes an airflow that might force the disk to vibrate. To characterize this vibration, a set of parameters was determined by measuring the tip clearance of the disk: the amplitude, the frequency and the number of nodal diameters in the disk...
January 15, 2017: Sensors
https://www.readbyqxmd.com/read/28098842/modulation-index-adjustment-for-recovery-of-pure-wavelength-modulation-spectroscopy-second-harmonic-signal-waveforms
#14
Wei Wei, Jun Chang, Qiang Wang, Zengguang Qin
A new technique of modulation index adjustment for pure wavelength modulation spectroscopy second harmonic signal waveforms recovery is presented. As the modulation index is a key parameter in determining the exact form of the signals generated by the technique of wavelength modulation spectroscopy, the method of modulation index adjustment is applied to recover the second harmonic signal with wavelength modulation spectroscopy. By comparing the measured profile with the theoretical profile by calculation, the relationship between the modulation index and average quantities of the scanning wavelength can be obtained...
January 15, 2017: Sensors
https://www.readbyqxmd.com/read/28098281/thermodynamic-stability-of-stoichiometric-lafeo3-and-bifeo3-a-hybrid-dft-study
#15
Eugene Heifets, Eugene A Kotomin, Alexander A Bagaturyants, Joachim Maier
BiFeO3 perovskite attracts great attention due to its multiferroic properties and potential use as a parent material for Bi1-xSrxFeO3-δ and Bi1-xSrxFe1-yCoyO3-δ solid solutions in intermediate temperature cathodes of oxide fuel cells. Another iron-based LaFeO3 perovskite is the end member for well-known solid solutions (La1-xSrxFe1-yCoyO3-δ) used for oxide fuel cells and other electrochemical devices. In this study an ab initio hybrid functional approach was used for the study of the thermodynamic stability of both LaFeO3 and BiFeO3 with respect to decompositions to binary oxides and to elements, as a function of temperature and oxygen pressure...
January 18, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28098278/understanding-the-connection-between-conformational-changes-of-peptides-and-equilibrium-thermal-fluctuations
#16
Miguel A Soler, José Zúñiga, Alberto Requena, Adolfo Bastida
Despite the increasing evidence that conformational transitions in peptides and proteins are driven by specific vibrational energy pathways along the molecule, the current experimental techniques of analysis do as yet not allow to study these biophysical processes in terms of anisotropic energy flows. Computational methods offer a complementary approach to obtain a more detailed understanding of the vibrational and conformational dynamics of these systems. Accordingly, in this work we investigate jointly the vibrational energy distribution and the conformational dynamics of trialanine peptide in water solution at room temperature by applying the Instantaneous Normal Mode analysis to the results derived from equilibrium molecular dynamics simulations...
January 18, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28098216/chemical-bonding-in-aqueous-hexacyano-cobaltate-from-photon-and-electron-detection-perspectives
#17
Sreeju Sreekantan Nair Lalithambika, Kaan Atak, Robert Seidel, Antje Neubauer, Tim Brandenburg, Jie Xiao, Bernd Winter, Emad F Aziz
The electronic structure of the [Co(CN)6](3-) complex dissolved in water is studied using X-ray spectroscopy techniques. By combining electron and photon detection methods from the solutions ionized or excited by soft X-rays we experimentally identify chemical bonding between the metal center and the CN ligand. Non-resonant photoelectron spectroscopy provides solute electron binding energies, and nitrogen 1 s and cobalt 2p resonant core-level photoelectron spectroscopy identifies overlap between metal and ligand orbitals...
January 18, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28097812/monitoring-immune-response-after-allogeneic-transplantation-of-mesenchymal-stem-cells-for-osteochondral-repair
#18
Elhussein Elbadry Mahmoud, Tanaka Yuka, Naosuke Kamei, Yohei Harada, Hideki Ohdan, Adachi Nobuo, Mitsuo Ochi
The aim of this study was to investigate safety of using allogeneic magnetically labeled mesenchymal stem cells (m-MSCs) to ameliorate osteochondral repair as well as autologous one, with immune surveillance using a mixed lymphocyte reaction (MLR) assay. Twenty knees of Japanese white rabbits were randomly divided into two groups: the control (autologous) group, the transplantation of 2 × 10(5)  m-MSCs and the experimental (allogeneic) group, transplantation of 2 × 10(5)  m-MSCs from Dutch rabbit was performed, with exposure to an external magnetic device for 10 minutes, then rabbits were euthanized after 12 weeks...
January 17, 2017: Journal of Tissue Engineering and Regenerative Medicine
https://www.readbyqxmd.com/read/28097073/handling-stress-may-confound-murine-gut-microbiota-studies
#19
Cary R Allen-Blevins, Xiaomeng You, Katie Hinde, David A Sela
BACKGROUND: Accumulating evidence indicates interactions between human milk composition, particularly sugars (human milk oligosaccharides or HMO), the gut microbiota of human infants, and behavioral effects. Some HMO secreted in human milk are unable to be endogenously digested by the human infant but are able to be metabolized by certain species of gut microbiota, including Bifidobacterium longum subsp. infantis (B. infantis), a species sensitive to host stress (Bailey & Coe, 2004). Exposure to gut bacteria like B...
2017: PeerJ
https://www.readbyqxmd.com/read/28097070/sponge-exhalent-seawater-contains-a-unique-chemical-profile-of-dissolved-organic-matter
#20
Cara L Fiore, Christopher J Freeman, Elizabeth B Kujawinski
Sponges are efficient filter feeders, removing significant portions of particulate and dissolved organic matter (POM, DOM) from the water column. While the assimilation and respiration of POM and DOM by sponges and their abundant microbial symbiont communities have received much attention, there is virtually no information on the impact of sponge holobiont metabolism on the composition of DOM at a molecular-level. We applied untargeted and targeted metabolomics techniques to characterize DOM in seawater samples prior to entering the sponge (inhalant reef water), in samples exiting the sponge (exhalent seawater), and in samples collected just outside the reef area (off reef seawater)...
2017: PeerJ
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