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https://www.readbyqxmd.com/read/29341660/2d-stress-tensor-for-4d-gravity
#1
Daniel Kapec, Prahar Mitra, Ana-Maria Raclariu, Andrew Strominger
We use the subleading soft-graviton theorem to construct an operator T_{zz} whose insertion in the four-dimensional tree-level quantum gravity S matrix obeys the Virasoro-Ward identities of the energy momentum tensor of a two-dimensional conformal field theory (CFT_{2}). The celestial sphere at Minkowskian null infinity plays the role of the Euclidean sphere of the CFT_{2}, with the Lorentz group acting as the unbroken SL(2,C) subgroup.
September 22, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/29340290/tailoring-four-dimensional-cone-beam-ct-acquisition-settings-for-fiducial-marker-based-image-guidance-in-radiation-therapy
#2
Peng Jin, Niek van Wieringen, Maarten C C M Hulshof, Arjan Bel, Tanja Alderliesten
Use of four-dimensional cone-beam CT (4D-CBCT) and fiducial markers for image guidance during radiation therapy (RT) of mobile tumors is challenging due to the trade-off among image quality, imaging dose, and scanning time. This study aimed to investigate different 4D-CBCT acquisition settings for good visibility of fiducial markers in 4D-CBCT. Using these 4D-CBCTs, the feasibility of marker-based 4D registration for RT setup verification and manual respiration-induced motion quantification was investigated...
April 2018: Journal of Medical Imaging
https://www.readbyqxmd.com/read/29339994/the-second-to-fourth-digit-ratio-in-elite-and-non-elite-greco-roman-wrestlers
#3
Mohammad Keshavarz, Mahdi Bayati, Babak Farzad, Amirbahador Dakhili, Hamid Agha-Alinejad
A low second-to-fourth digit ratio (2D:4D) has been reported to correlate with high performance and athletic potential of an individual in sport. It has been suggested that 2D:4D is a relatively weak predictor of strength and a stronger predictor of efficiency in aerobic exercise. Comparing extreme groups on a continuum of sports performance requiring high power (physical strength) output would be helpful to resolve this issue. Therefore, the purpose of the present study was to compare the 2D:4D ratio of world-class elite Greco-Roman wrestlers (n = 10) taking part in Olympic fitness camps in 2013 with the 2D:4D ratio of non-elite collegiate wrestlers (n = 20), and age-matched sedentary males (n = 40)...
December 2017: Journal of Human Kinetics
https://www.readbyqxmd.com/read/29339575/dynamic-pet-image-reconstruction-integrating-temporal-regularization-associated-with-respiratory-motion-correction-for-applications-in-oncology
#4
Thibaut Merlin, Dimitris Visvikis, Philippe Fernandez, Frederic Lamare
Respiratory motion reduces both the qualitative and quantitative accuracy of PET images in oncology. This impact is more significant for quantitative applications based on kinetic modeling, where dynamic acquisitions are associated with limited statistics due to the necessity of enhanced temporal resolution. The aim of this study is to address these drawbacks by combining within a unique reconstruction algorithm in dynamic PET imaging, a respiratory motion correction approach, as well as a temporal regularization...
January 17, 2018: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/29338327/respiratory-gated-pet-ct-for-pulmonary-lesion-characterisation-promises-and-problems
#5
Russell Frood, Garry McDermott, Andrew Scarsbrook
2-Deoxy-2-(18Fluorine)-fluoro-D-glucose (FDG) positron emission tomography/computed tomography (PET/CT) is an integral part of lung carcinoma staging and frequently used in the assessment of solitary pulmonary nodules. However, a limitation of conventional 3D PET/CT when imaging the thorax is its susceptibility to motion artefact which blurs the signal from the lesion resulting in inaccurate representation of size and metabolic activity. Respiratory gated (4D) PET/CT aims to negate the effects of motion artefact and provide a more accurate interpretation of pulmonary nodules and lymphadenopathy...
January 17, 2018: British Journal of Radiology
https://www.readbyqxmd.com/read/29336877/sin-quadratic-model-for-chest-tomosynthesis-respiratory-signal-analysis-and-its-application-in-four-dimensional-chest-tomosynthesis-reconstruction
#6
Xi Tao, Hua Zhang, Genggeng Qin, Jianhua Ma, Qianjin Feng, Wufan Chen
Chest tomosynthesis (CTS) is a newly developed imaging technique which provides pseudo-3D volume anatomical information of thorax from limited-angle projections and contains much less of superimposed anatomy than the chest X-ray radiography. One of the relatively common problems in CTS is the patient respiratory motion during image acquisition, which negatively impacts the detectability. In this work, we propose a sin-quadratic model to analyze the respiratory motion during CTS scan, which is a real time method where the respiratory signal is generated by extracting the motion of diaphragm from projection radiographs...
January 11, 2018: Medical Engineering & Physics
https://www.readbyqxmd.com/read/29333043/picroside-i-and-picroside-ii-from-tissue-cultures-of-picrorhiza-kurroa
#7
Yamjala Ganeshkumar, Ajmera Ramarao, Ciddi Veeresham
Background: Picrorhiza kurroa (PK) belongs to Scrophulariaceae family and is a representative endemic, medicinal herb, widely distributed throughout the higher altitudes of alpine Himalayas from west to east, between 3000 and 4500 m above mean sea level. Objective: The objective of the present study is to assess the production of picroside I and picroside II from tissue cultures of PK. Materials and Methods: Auxiliary shoot tips of PK were incubated in Murashige and Skoog medium supplemented with indole-3-butyric acid and kinetin phytohormones...
December 2017: Pharmacognosy Research
https://www.readbyqxmd.com/read/29332606/tricuspid-flow-and-regurgitation-in-congenital-heart-disease-and-pulmonary-hypertension-comparison-of-4d-flow-cardiovascular-magnetic-resonance-and-echocardiography
#8
Mieke M P Driessen, Marjolijn A Schings, Gertjan Tj Sieswerda, Pieter A Doevendans, Erik H Hulzebos, Marco C Post, Repke J Snijder, Jos J M Westenberg, Arie P J van Dijk, Folkert J Meijboom, Tim Leiner
BACKGROUND: Tricuspid valve (TV) regurgitation (TR) is a common complication of pulmonary hypertension and right-sided congenital heart disease, associated with increased morbidity and mortality. Estimation of TR severity by echocardiography and conventional cardiovasvular magnetic resonance (CMR) is not well validated and has high variability. 4D velocity-encoded (4D-flow) CMR was used to measure tricuspid flow in patients with complex right ventricular (RV) geometry and varying degrees of TR...
January 15, 2018: Journal of Cardiovascular Magnetic Resonance
https://www.readbyqxmd.com/read/29332600/finding-novel-anti-carcinomas-compounds-by-targeting-sfrp4-through-molecular-modeling-docking-and-dynamic-simulation-studies
#9
M Hassan, M Azhar, Q Abbas, H Reza, A A Moustafa, S Shahzadi, Z Ashraf, S Y Seo
BACKGROUND: Secreted frizzled-related protein 4 (SFRP4) is a glycoprotein that act as a competitor of both canonical and non-canonical Wnt pathways. SFRP4 is mostly expressed in ovary and played a significant role as a target molecule to cure ovarian carcinoma. OBJECTIVE: Multiple chemical agonists are being used to cure ovary melanoma. We are interested to theoretically analyze the compounds through computational approaches for their inhibitory effects against SFRP4...
January 11, 2018: Current Computer-aided Drug Design
https://www.readbyqxmd.com/read/29331311/prediction-of-mortality-in-patients-with-chronic-obstructive-pulmonary-disease-with-the-new-global-initiative-for-chronic-obstructive-lung-disease-2017-classification-a-cohort-study
#10
Anne Gedebjerg, Szimonetta Komjáthiné Szépligeti, Laura-Maria Holm Wackerhausen, Erzsébet Horváth-Puhó, Ronald Dahl, Jens Georg Hansen, Henrik Toft Sørensen, Mette Nørgaard, Peter Lange, Reimar Wernich Thomsen
BACKGROUND: The Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2017 classification separates the spirometric 1-4 staging from the ABCD groups defined by symptoms and exacerbations. Little is known about how this new classification predicts mortality in patients with chronic obstructive pulmonary disease (COPD). We aimed to establish the predictive ability of the GOLD 2017 classification, compared with earlier classifications, for all-cause and respiratory mortality, both when using its main ABCD groups and when further subdividing according to spirometric 1-4 staging...
January 10, 2018: Lancet Respiratory Medicine
https://www.readbyqxmd.com/read/29329709/characterization-of-singly-and-multiply-pegylated-insulin-isomers-by-reversed-phase-ultra-performance-liquid-chromatography-interfaced-with-ion-mobility-mass-spectrometry
#11
Selim Gerislioglu, Scott R Adams, Chrys Wesdemiotis
Conjugation of poly(ethylene glycol) (PEG) to protein drugs (PEGylation) is increasingly utilized in the biotherapeutics field because it improves significantly the drugs' circulatory half-life, solubility, and shelf-life. The activity of a PEGylated drug depends on the number, size, and location of the attached PEG chain(s). This study introduces a 2D separation approach, including reversed-phase ultra-performance liquid chromatography (RP-UPLC) and ion mobility mass spectrometry (IM-MS), in order to determine the structural properties of the conjugates, as demonstrated for a PEGylated insulin sample that was prepared by random amine PEGylation...
April 3, 2018: Analytica Chimica Acta
https://www.readbyqxmd.com/read/29328048/a-biomechanical-modeling-guided-simultaneous-motion-estimation-and-image-reconstruction-technique-smeir-bio-for-4d-cbct-reconstruction
#12
Xiaokun Huang, You Zhang, Jing Wang
Reconstructing four-dimensional cone-beam computed tomography (4D-CBCT) images directly from respiratory phase-sorted traditional 3D-CBCT projections can capture target motion trajectory, reduce motion artifacts, and reduce imaging dose and time. However, the limited numbers of projections in each phase after phase-sorting decreases CBCT image quality under traditional reconstruction techniques. To address this problem, we developed a simultaneous motion estimation and image reconstruction (SMEIR) algorithm, an iterative method that can reconstruct higher quality 4D-CBCT images from limited projections using an inter-phase intensity-driven motion model...
January 12, 2018: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/29327165/measurement-of-cardiac-valve-and-aortic-blood-flow-velocities-in-stroke-patients-a-comparison-of-4d-flow-mri-and-echocardiography
#13
Thomas Wehrum, Felix Guenther, Alexander Fuchs, Florian Schuchardt, Anja Hennemuth, Andreas Harloff
4D flow MRI is an emerging technique that allows quantification of 3D blood flow in vivo. However, comparisons with methods of blood velocity quantification used in clinical routine are sparse. Therefore, we compared velocity quantification using 4D flow MRI with transthoracic and transesophageal echocardiography at the mitral and aortic valves and the aorta. Forty-eight stroke patients (age 67.3 ± 15.0 years) were examined by 4D flow MRI. Blood flow velocities were assessed using standardized 2D analysis planes positioned in the mitral valve (MV), aortic valve (AV), ascending aorta (AAo), and descending aorta (DAo) and were compared with echocardiography...
January 11, 2018: International Journal of Cardiovascular Imaging
https://www.readbyqxmd.com/read/29325780/longitudinal-atlas-for-normative-human-brain-development-and-aging-over-the-lifespan-using-quantitative-susceptibility-mapping
#14
Yuyao Zhang, Hongjiang Wei, Matthew J Cronin, Naying He, Fuhua Yan, Chunlei Liu
Longitudinal brain atlases play an important role in the study of human brain development and cognition. Existing atlases are mainly based on anatomical features derived from T1-and T2-weighted MRI. A 4D developmental quantitative susceptibility mapping (QSM) atlas may facilitate the estimation of age-related iron changes in deep gray matter nuclei and myelin changes in white matter. To this end, group-wise co-registered QSM templates were generated over various age intervals from age 1-83 years old. Registration was achieved by combining both T1-weighted and QSM images...
January 8, 2018: NeuroImage
https://www.readbyqxmd.com/read/29324591/visualization-from-intraoperative-swept-source-microscope-integrated-optical-coherence-tomography-in-vitrectomy-for-complications-of-proliferative-diabetic-retinopathy
#15
Hesham Gabr, Xi Chen, Oscar M Zevallos-Carrasco, Christian Viehland, Alexandria Dandrige, Neeru Sarin, Tamer H Mahmoud, Lejla Vajzovic, Joseph A Izatt, Cynthia A Toth
PURPOSE: To evaluate the use of live volumetric (4D) intraoperative swept-source microscope-integrated optical coherence tomography in vitrectomy for proliferative diabetic retinopathy complications. METHODS: In this prospective study, we analyzed a subgroup of patients with proliferative diabetic retinopathy complications who required vitrectomy and who were imaged by the research swept-source microscope-integrated optical coherence tomography system. In near real time, images were displayed in stereo heads-up display facilitating intraoperative surgeon feedback...
January 10, 2018: Retina
https://www.readbyqxmd.com/read/29324286/digit-ratio-2d-4d-and-circulating-testosterone-oestradiol-and-progesterone-levels-across-the-menstrual-cycle
#16
Gareth Richards, Magdalena Klimek, Grazyna Jasienska, Urszula M Marcinkowska
BACKGROUND: Digit ratio (2D:4D) is used by researchers as an indicator of prenatal sex hormone exposure. Two previous studies have examined associations between 2D:4D and circulating sex steroid concentrations across the menstrual cycle in adult females. One reported that digit ratio correlated positively with oestradiol levels, whereas the other found no such effect; neither observed significant associations with progesterone. AIMS: To examine associations between 2D:4D, as well as asymmetry (i...
January 8, 2018: Early Human Development
https://www.readbyqxmd.com/read/29324241/low-dimensional-representation-of-cardiac-motion-using-barycentric-subspaces-a-new-group-wise-paradigm-for-estimation-analysis-and-reconstruction
#17
Marc-Michel Rohé, Maxime Sermesant, Xavier Pennec
One major challenge when trying to build low-dimensional representation of the cardiac motion is its natural circular pattern during a cycle, therefore making the mean image a poor descriptor of the whole sequence. Therefore, traditional approaches for the analysis of the cardiac deformation use one specific frame of the sequence - the end-diastolic (ED) frame - as a reference to study the whole motion. Consequently, this methodology is biased by this empirical choice. Moreover, the ED image might be a poor reference when looking at large deformation for example at the end-systolic (ES) frame...
December 23, 2017: Medical Image Analysis
https://www.readbyqxmd.com/read/29323745/the-dancing-thrombus-4d-transesophageal-echocardiography-in-the-diagnosis-of-a-pedunculated-left-atrial-appendage-thrombus
#18
Faith R Kelly, Christopher Dire, Rosco S Gore
It is rare that a left atrial appendage thrombus will grow to the extent that it can prolapse into the left ventricle. We report the case of a large prolapsing left atrial thrombus diagnosed by 3D echocardiography in a patient presenting with a transient ischemic attack.
January 11, 2018: Echocardiography
https://www.readbyqxmd.com/read/29322310/relationship-between-sagittal-spinal-curves-geometry-and-isokinetic-trunk-muscle-strength-in-adults
#19
Walaa Elsayed, Ahmed Farrag, Qassim Muaidi, Nora Almulhim
PURPOSE: Sagittal spinal deviation has been reported to be a significant musculoskeletal problem affecting both genders and could develop at any age. Factors triggering this issue are still not well defined. The purpose of this study was to investigate the relationship between sagittal spine angles and isokinetic peak, average torque, and power of trunk muscles in asymptomatic adults. METHODS: A convenient sample of 79 subjects with asymptomatic spine participated in this study...
January 10, 2018: European Spine Journal
https://www.readbyqxmd.com/read/29318774/one-pot-synthesis-of-anilides-herbicidal-activity-and-molecular-docking-study
#20
Suélen K Sartori, Elson S Alvarenga, Cristiane A Franco, Danielle S Ramos, Denilson F Oliveira
BACKGROUND: Considering the demand for more efficient herbicides, the present work aimed at synthesizing anilides via simple methods, and evaluate their herbicidal activities through seed germination assays. In silico studies were carried out to identify the enzymatic target sitein the plants for the most active anilides. RESULTS: A total of eighteen anilides were prepared via one-pot reaction in yields which varied from 36 to 98% through reactions of anilines with sorbic chloride and hexanoic anhydride...
January 9, 2018: Pest Management Science
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