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CT theory and use

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https://www.readbyqxmd.com/read/28724865/proposal-of-a-new-index-based-on-signal-to-noise-ratio-for-low-contrast-detectability-in-computed-tomographic-imaging
#1
Junichi Hashimoto, Shinji Abe, Yoshiyuki Ishimori, Masahiko Monma, Akio Tsumuraya, Kaneyoshi Miyauchi
The low-contrast detectability of computed tomography (CT) images is commonly evaluated by the contrast-to-noise ratio (CNR) because of its convenience to measure. However, the correlation between CNR and visual detectability is poor because the CNR is a simple index determined by both the contrast of the object and the standard deviation of the image noise. On the other hand, the signal-to-noise ratio (SNR), especially SNR based on the statistical decision theory model (SNRS, D) and SNR based on the matched-filter model (SNRM) are considered superior to CNR...
2017: Nihon Hoshasen Gijutsu Gakkai Zasshi
https://www.readbyqxmd.com/read/28715692/propping-the-optical-and-electronic-properties-of-potential-photo-sensitizers-with-different-%C3%AF-spacers-td-dft-insights
#2
Basant A Ali, Nageh K Allam
We report density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations on the widely used N3 dye (cis-[Ru(2,2'-bipyridine-4,4'-dicarboxylic acid)2(NCS)2] and its trans isomer with different π-spacers. The study compared the sensitization properties of the two isomers in terms of their electronic properties such as light harvesting efficiency (LHE), absorbed wavelength (λMax) and molecular orbital distribution. Also, charge transfer descriptors, such as the charge transfer distance (D(CT)), dipole moment (μ(CT)), and the amount of charge transferred (q(CT)) were investigated...
July 12, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28697576/sparse-view-image-reconstruction-via-total-absolute-curvature-combining-total-variation-for-x-ray-computed-tomography
#3
Zhizhong Zheng, Ailong Cai, Lei Li, Bin Yan, Fulong Le, Linyuan Wang, Guoen Hu
Sparse-view imaging is a promising scanning approach which has fast scanning rate and low-radiation dose in X-ray computed tomography (CT). Conventional L1-norm based total variation (TV) has been widely used in image reconstruction since the advent of compressive sensing theory. However, with only the first order information of the image used, the TV often generates dissatisfactory image for some applications. As is widely known, image curvature is among the most important second order features of images and can potentially be applied in image reconstruction for quality improvement...
July 7, 2017: Journal of X-ray Science and Technology
https://www.readbyqxmd.com/read/28676768/beyond-monologicality-exploring-conspiracist-worldviews
#4
Bradley Franks, Adrian Bangerter, Martin W Bauer, Matthew Hall, Mark C Noort
Conspiracy theories (CTs) are widespread ways by which people make sense of unsettling or disturbing cultural events. Belief in CTs is often connected to problematic consequences, such as decreased engagement with conventional political action or even political extremism, so understanding the psychological and social qualities of CT belief is important. CTs have often been understood to be "monological," displaying the tendency for belief in one conspiracy theory to be correlated with belief in (many) others...
2017: Frontiers in Psychology
https://www.readbyqxmd.com/read/28660812/sex-differences-in-the-splenic-flexure
#5
A F Brookes, Caw Macano, T Stone, M Cheetham, L Meecham
INTRODUCTION Anecdotally, surgeons claim splenic flexure mobilisation is more difficult in male patients. There have been no scientific studies to confirm or disprove this hypothesis. The implications in colorectal surgery could be profound. The aim of this study was to assess quantitatively whether there is an anatomical difference in the position of the splenic flexure between men and women using computed tomography (CT). METHODS Portal venous phase CT performed for preoperative assessment of colorectal malignancy was analysed using the hospital picture archiving and communication system...
July 2017: Annals of the Royal College of Surgeons of England
https://www.readbyqxmd.com/read/28660372/a-finite-element-study-of-traditional-chinese-cervical-manipulation
#6
Zhen Deng, Kuan Wang, Huihao Wang, Tianying Lan, Hongsheng Zhan, Wenxin Niu
PURPOSE: Traditional Chinese cervical manipulation (TCCM) has been claimed as an effective treatment for diseases of the cervical spine, but its biomechanical effects on the vertebral body and intervertebral discs remain unclear. The aim of this study was to develop and validate a detailed finite element model of cervical spine, which was then used to investigate the biomechanical response of the cervical spine to TCCM. METHODS: The model of a C2-T1 cervical spine was constructed based on CT images of a healthy male volunteer and validated against published in vitro studies under different loading conditions...
June 28, 2017: European Spine Journal
https://www.readbyqxmd.com/read/28646272/rhesus-cochlear-and-vestibular-functions-are-preserved-after-inner-ear-injection-of-saline-volume-sufficient-for-gene-therapy-delivery
#7
Chenkai Dai, Mohamed Lehar, Daniel Q Sun, Lani Swarthout Rvt, John P Carey, Tim MacLachlan, Doug Brough, Hinrich Staecker, Alexandra M Della Santina, Timothy E Hullar, Charles C Della Santina
Sensorineural losses of hearing and vestibular sensation due to hair cell dysfunction are among the most common disabilities. Recent preclinical research demonstrates that treatment of the inner ear with a variety of compounds, including gene therapy agents, may elicit regeneration and/or repair of hair cells in animals exposed to ototoxic medications or other insults to the inner ear. Delivery of gene therapy may also offer a means for treatment of hereditary hearing loss. However, injection of a fluid volume sufficient to deliver an adequate dose of a pharmacologic agent could, in theory, cause inner ear trauma that compromises functional outcome...
June 23, 2017: Journal of the Association for Research in Otolaryngology: JARO
https://www.readbyqxmd.com/read/28634897/the-effect-of-surgical-technique-and-spacer-texture-on-bone-regeneration-a-caprine-study-using-the-masquelet-technique
#8
Viviane Luangphakdy, G Elizabeth Pluhar, Nicolás S Piuzzi, Jean-Claude D'Alleyrand, Cathy S Carlson, Joan E Bechtold, Jonathan Forsberg, George F Muschler
BACKGROUND: The Masquelet-induced-membrane technique is a commonly used method for treating segmental bone defects. However, there are no established clinical standards for management of the induced membrane before grafting. QUESTIONS/PURPOSES: Two clinically based theories were tested in a chronic caprine tibial defect model: (1) a textured spacer that increases the induced-membrane surface area will increase bone regeneration; and (2) surgical scraping to remove a thin tissue layer of the inner induced-membrane surface will enhance bone formation...
June 20, 2017: Clinical Orthopaedics and related Research
https://www.readbyqxmd.com/read/28633299/structural-covariance-networks-in-children-with-autism-or-adhd
#9
R A I Bethlehem, R Romero-Garcia, E Mak, E T Bullmore, S Baron-Cohen
Background: While autism and attention-deficit/hyperactivity disorder (ADHD) are considered distinct conditions from a diagnostic perspective, clinically they share some phenotypic features and have high comorbidity. Regardless, most studies have focused on only one condition, with considerable heterogeneity in their results. Taking a dual-condition approach might help elucidate shared and distinct neural characteristics. Method: Graph theory was used to analyse topological properties of structural covariance networks across both conditions and relative to a neurotypical (NT; n = 87) group using data from the ABIDE (autism; n = 62) and ADHD-200 datasets (ADHD; n = 69)...
June 13, 2017: Cerebral Cortex
https://www.readbyqxmd.com/read/28629942/can-a-target-zone-safer-than-lewinnek-s-safe-zone-be-defined-to-prevent-instability-of-total-hip-arthroplasties-case-control-study-of-56-dislocated-tha-and-93-matched-controls
#10
N Reina, S Putman, R Desmarchelier, E Sari Ali, P Chiron, M Ollivier, J Y Jenny, D Waast, C Mabit, E de Thomasson, C Schwartz, P Oger, L E Gayet, H Migaud, N Ramdane, M H Fessy
BACKGROUND: Various factors contribute to instability of total hip arthroplasty (THA), with implant orientation being a major contributor. We performed a case-control study with computed tomography (CT) data to determine whether: 1) orientation contributes to THA instability and 2) a safer target zone for stability than Lewinnek's classic safe zone can be defined. MATERIAL AND METHODS: We included prospectively 363 cases of THA dislocation that occurred during the calendar 2013 year in 24 participating hospitals...
June 16, 2017: Orthopaedics & Traumatology, Surgery & Research: OTSR
https://www.readbyqxmd.com/read/28622019/patient-perceptions-of-illness-identity-in-cancer-clinical-trial-decision-making
#11
Angela L Palmer-Wackerly, Phokeng M Dailey, Jessica L Krok-Schoen, Nancy D Rhodes, Janice L Krieger
When patients are diagnosed with cancer, they begin to negotiate their illness identity in relation to their past and future selves, their relationships, and their group memberships. Thus, how patients view their cancer in relation to their other identities may affect how and why they make particular decisions about treatment options. Using the Communication Theory of Identity (CTI), the current study explores: (1) how and why illness identity is framed across identity layers in relation to one particular cancer treatment: participation in a cancer clinical trial (CT); and (2) how and why patients experience identity conflicts while making their treatment decisions...
June 16, 2017: Health Communication
https://www.readbyqxmd.com/read/28607762/can-visual-assessment-of-blood-flow-patterns-by-dynamic-contrast-enhanced-computed-tomography-distinguish-between-malignant-and-benign-lung-tumors
#12
Stefan Walbom Harders, Hans Henrik Madsen, Hanne Marie Nellemann, Torben Riis Rasmussen, Jesper Thygesen, Henrik Hager, Niels Trolle Andersen, Finn Rasmussen
BACKGROUND: Dynamic contrast-enhanced computed tomography (DCE-CT) is a tool, which, in theory, can quantify the blood flow and blood volume of tissues. In structured qualitative analysis, parametric color maps yield a visual impression of the blood flow and blood volume within the tissue being studied, allowing for quick identification of the areas with the highest or lowest blood flow and blood volume. PURPOSE: To examine whether DCE-CT could be used to distinguish between malignant and benign lung tumors in patients with suspected lung cancer...
May 2017: Acta Radiologica Open
https://www.readbyqxmd.com/read/28595390/electron-phonon-coupling-in-anthracene-pyromellitic-dianhydride
#13
Derek Vermeulen, Nathan Corbin, Katelyn P Goetz, Oana D Jurchescu, Veaceslav Coropceanu, L E McNeil
In this study, the electron-phonon coupling constants of the mixed-stack organic semiconductor anthracene-pyromellitic dianhydride (A-PMDA) are determined from experimental resonant Raman and absorption spectra of the charge transfer (CT) exciton using a time-dependent resonant Raman model. The reorganization energies of both intermolecular and intramolecular phonons are determined and compared with theoretical estimates derived from density functional theory calculations; they are found to agree well. We found that the dominant contribution to the total reorganization energy is due to intramolecular phonons, with intermolecular phonons only contributing a small percentage...
June 7, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28586703/exploring-the-potential-of-boron-doped-nanographene-as-efficient-charge-transport-and-nonlinear-optical-material-a-first-principles-study
#14
Ahmad Irfan, Aijaz Rasool Chaudhry, Shabbir Muhammad, Abdullah G Al-Sehemi
Owing to their excellent electrochemical properties, graphenes found applications in several fields ranging from semiconductors, solar cells, field effect transistors, and nanoscale electronic devices as well as in nonlinear optical (NLO) applications. The structural features, electro-optical, charge transport and nonlinear optical properties of the boron-doped graphene (BG) compound 1 were studied using density functional theory methods The BG compound comprises a central electron deficient site of boron atoms, which can serve as electron acceptor while terminal alkoxy groups as donors leading to powerful donor-π-acceptor (D-π-A) configuration...
May 26, 2017: Journal of Molecular Graphics & Modelling
https://www.readbyqxmd.com/read/28573550/optimal-injection-method-for-long-range-computed-tomography-angiography
#15
Aogu Yamaguchi, Tsukasa Sasaki
We aimed to obtain high-stable computed tomography (CT) values for CT angiography (CTA). We verified the optimal use of the new protocol for long-range scanning using a contrast material flow phantom (Ichikawa, CT imaging theory. Igaku syoin Publishing, Tokyo, 8; Awai et al., Am J Roentgenol 186(2):379-385, 1) to obtain high-stable CT values (Fig. 2). We have developed a novel contrast injection method called the stable line imaging protocol (SLIP). This method involved a gradual reduction in the rate of administration of the contrast medium, which was accompanied by simultaneous administration of saline to compensate for the resultant decrease in the rate of administration...
June 1, 2017: Radiological Physics and Technology
https://www.readbyqxmd.com/read/28535909/dynamic-simulation-and-doppler-ultrasonography-validation-of-blood-flow-behavior-in-abdominal-aortic-aneurysm
#16
Cristian C Botar, Árpád Á Tóth, Olivera R Klisurić, Dijana D Nićiforović, Viktorija A Vučaj Ćirilović, Viktor E Till
Criteria for rupture prediction of Abdominal Aortic Aneurysm (AAA) are based only on the diameter of AAA. This method does not consider complex hemodynamic forces exerted on AAA wall. The methodology used in our study combines Computer-Aided Design (CAD) with Computational Fluid Dynamics (CFD). Three-dimensional vascular structures reconstructions were based on Computed Tomography (CT) images and CAD. CFD theory was used for mathematical modeling and simulations. In this way, dynamic behavior of blood flow in bounded three-dimensional space was described...
May 2017: Physica Medica: PM
https://www.readbyqxmd.com/read/28513677/regular-and-red-shifted-fluorescence-of-the-donor-acceptor-compound-5-1h-pyrrole-1-yl-thiophenecarbonitrile-tcn-is-efficiently-quenched-by-internal-modes-of-thiophene
#17
Mercedes V Bohnwagner, Irene Burghardt, Andreas Dreuw
The photochemical properties of thiophene analogs of N-pyrrolobenzonitrile (PBN), notably the two isomers 5-(1H-pyrrole-1-yl)thiophene-2-carbonitrile (2-TCN) and 5-(1H-pyrrole-1-yl)thiophene-3-carbonitrile (3-TCN) have been investigated. The aim of this study is to reveal whether the donor-acceptor compound TCN shows a fluorescence behavior similar to other benzonitrile derivatives like PBN and N,N-dimethylaminobenzonitrile (DMABN). For this purpose high-level ab initio methods have been employed comprising approximate coupled cluster (CC2) methods, the algebraic-diagramatic construction scheme for the polarization propagator (ADC(2) and ADC(3)) as well as time-dependent density functional theory (TDDFT)...
May 31, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28505565/dft-and-td-dft-theoretical-studies-on-photo-induced-electron-transfer-process-on-cefamandole-c60-nano-complex
#18
Avat Arman Taherpour, Morteza Jamshidi, Omid Rezaei
The C60 fullerene displays a considerable electronegativity. It has a unique photophysical and electrochemical behavior that can be used as a suitable drug carrier. In the present study, the interaction of C60 fullerene as an electron recipient with the Cefamandole antibiotic was investigated in both ground and excited states using DFT and TD-DFT methods. The study of the interaction of C60 and Cefamandole via electron localization function (ELF) and reduced density gradient (RDG) revealed that the complex formation is of van der Waals type...
April 27, 2017: Journal of Molecular Graphics & Modelling
https://www.readbyqxmd.com/read/28493805/creating-three-dimensional-printed-models-of-acetabular-fractures-for-use-as-educational-tools
#19
Matthew S Manganaro, Yoav Morag, William J Weadock, Corrie M Yablon, Kara Gaetke-Udager, Erica B Stein
Acetabular fractures are frequently encountered in some clinical practices, and the precise classification of these fractures greatly influences treatments and outcomes. The authors identified the need for an educational aid when teaching acetabular fracture classifications, given the complex spatial anatomy and the nonintuitive classification system that is commonly used. Three-dimensional ( 3D three-dimensional ) printing is an evolving technique that has applications as an educational aid, providing the student with a tangible object to interact with and learn from...
May 2017: Radiographics: a Review Publication of the Radiological Society of North America, Inc
https://www.readbyqxmd.com/read/28493717/-2-2-type-reaction-of-metal-metal-%C3%AF-bond-with-fullerene-forming-an-%C3%AE-1-c60-metal-complex-mechanistic-details-of-formation-reaction-and-prediction-of-a-new-%C3%AE-1-c60-metal-complex
#20
Hong Zheng, Xiang Zhao, Shigeyoshi Sakaki
C60[CpRu(CO)2]2 is only one transition-metal fullerene complex with pure η(1)-coordinated bonds, which was recently synthesized through the reaction between dinuclear Ru complex [CpRu(CO)2]2 and C60. Though new properties can be expected in the η(1)-coordinated metal-fullerene complex, its characteristic features are unclear, and the [2 + 2]-type formation reaction is very slow with a very small yield. A density functional theory study discloses that the η(1)-coordinated bond is formed by a large overlap between the Ru dσ orbital and C pσ one involved in the lowest unoccupied molecular orbital (LUMO) (π*) of C60 unlike the well-known η(2)-coordinated metal-fullerene complex which has a π-type coordinate bond with metal dπ orbital...
May 11, 2017: Inorganic Chemistry
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