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https://www.readbyqxmd.com/read/29150683/null-functions-in-three-dimensional-imaging-of-alpha-and-beta-particles
#1
Yijun Ding, Luca Caucci, Harrison H Barrett
Null functions of an imaging system are functions in the object space that give exactly zero data. Hence, they represent the intrinsic limitations of the imaging system. Null functions exist in all digital imaging systems, because these systems map continuous objects to discrete data. However, the emergence of detectors that measure continuous data, e.g. particle-processing (PP) detectors, has the potential to eliminate null functions. PP detectors process signals produced by each particle and estimate particle attributes, which include two position coordinates and three components of momentum, as continuous variables...
November 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29148586/a-dynamic-ultrasound-simulation-of-a-pulsating-three-layered-cca-for-validation-of-2d-wall-motion-and-blood-velocity-estimation-algorithms
#2
Xiao Hu, Yufeng Zhang, Guanghui Cai, Kexin Zhang, Li Deng, Lian Gao, Suya Han, Jianhua Chen
PURPOSE: A dynamic ultrasound simulation model for the common carotid artery (CCA) with three arterial layers for validation of 2D wall motion and blood velocity estimation algorithms is proposed in present study. This model describes layers with not only characteristics of echo distributions conforming to clinical ones, but also varying thicknesses, axial and radial displacements with pulsatile blood pressure during a cardiac cycle. METHODS: The modeling process is as follows: first, a geometrical model according with the clinical structure size of a CCA is built based on the preset layer thicknesses and the diameter of lumen...
November 17, 2017: Medical Physics
https://www.readbyqxmd.com/read/29147547/multi-dimensional-charge-transport-in-supramolecular-helical-foldamer-assemblies
#3
Alejandro Méndez-Ardoy, Nagula Markandeya, Xuesong Li, Yu-Tang Tsai, Gilles Pecastaings, Thierry Buffeteau, Victor Maurizot, Luca Muccioli, Frédéric Castet, Ivan Huc, Dario M Bassani
Aromatic foldamers are bioinspired architectures whose potential use in materials remains largely unexplored. Here we report our investigation of vertical and horizontal charge transport over long distances in helical oligo-quinolinecarboxamide foldamers organized as single monolayers on Au or SiO2. Conductive atomic force microscopy showed that vertical conductivity is efficient and that it displays a low attenuation with foldamer length (0.06 Å(-1)). In contrast, horizontal charge transport is found to be negligible, demonstrating the strong anisotropy of foldamer monolayers...
October 1, 2017: Chemical Science
https://www.readbyqxmd.com/read/29147143/analyzing-text-recognition-from-tactually-evoked-eeg
#4
A Khasnobish, S Datta, R Bose, D N Tibarewala, A Konar
Tactual exploration of objects produce specific patterns in the human brain and hence objects can be recognized by analyzing brain signals during tactile exploration. The present work aims at analyzing EEG signals online for recognition of embossed texts by tactual exploration. EEG signals are acquired from the parietal region over the somatosensory cortex of blindfolded healthy subjects while they tactually explored embossed texts, including symbols, numbers, and alphabets. Classifiers based on the principle of supervised learning are trained on the extracted EEG feature space, comprising three features, namely, adaptive autoregressive parameters, Hurst exponents, and power spectral density, to recognize the respective texts...
December 2017: Cognitive Neurodynamics
https://www.readbyqxmd.com/read/29146931/a-novel-magnet-actuated-droplet-manipulation-platform-using-a-floating-ferrofluid-film
#5
Chao Yang, Gang Li
In this paper, we propose a novel but versatile magnet-actuated platform for droplet manipulation, which uses a ferrofluid film floating on a liquid surface as magnetic actuator. In contrast to the traditional magnetic droplet manipulation, this platform can handle droplets without magnetically functionalizing them. Due to the immiscibility of the oil-based ferrofluid and water, the droplets desired to be manipulated can stably rest on the surface of the floating ferrofluid film (FFF) under the action of surface tension, thereby offering possibilities for magnetically-driven droplet manipulations...
November 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29145044/image-processing-for-precise-three-dimensional-registration-and-stitching-of-thick-high-resolution-laser-scanning-microscopy-image-stacks
#6
Chloé Murtin, Carole Frindel, David Rousseau, Kei Ito
The possible depth of imaging of laser-scanning microscopy is limited not only by the working distances of objective lenses but also by image degradation caused by attenuation and diffraction of light passing through the specimen. To tackle this problem, one can either flip the sample to record images from both sides of the specimen or consecutively cut off shallow parts of the sample after taking serial images of certain thickness. Multiple image substacks acquired in these ways should be combined afterwards to generate a single stack...
November 8, 2017: Computers in Biology and Medicine
https://www.readbyqxmd.com/read/29142281/the-phase-diagram-and-stability-of-trapped-d-dimensional-spin-orbit-coupled-bose-einstein-condensate
#7
Zi-Fa Yu, Ju-Kui Xue
By variational analysis and direct numerical simulation, we study the phase transition and stability of a trapped D-dimensional Bose-Einstein condensate with spin-orbit coupling. The complete phase and stability diagrams of the system are presented in full parameter space, while the collapse dynamics induced by the mean-filed attraction and the mechanism for stabilizing the collapse by spin-orbit coupling are illustrated explicitly. Particularly, a full and deep understanding of the dependence of phase transition and stability mechanism on geometric dimensionality and external trap potential is revealed...
November 15, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29142152/indirect-proton-mr-imaging-and-kinetic-analysis-of-17-o-labeled-water-tracer-in-the-brain
#8
Kohsuke Kudo, Taisuke Harada, Hiroyuki Kameda, Ikuko Uwano, Fumio Yamashita, Satomi Higuchi, Kunihiro Yoshioka, Makoto Sasaki
PURPOSE: The feasibility of steady-state sequences for (17)O imaging was evaluated based on a kinetic analysis of the brain parenchyma and cerebrospinal fluid (CSF). MATERIALS AND METHODS: The institutional review board approved this prospective study with written informed consent. Dynamic 2D or 3D steady-state sequences were performed in five and nine participants, respectively, with different parameters using a 3T scanner. During two consecutive dynamic scans, saline was intravenously administered for control purposes in the first scan, and 20% (17)O-labeled water (1 mL/Kg) was administered in the second scan...
November 16, 2017: Magnetic Resonance in Medical Sciences: MRMS
https://www.readbyqxmd.com/read/29140783/blending-face-details-synthesizing-a-face-using-multiscale-face-models
#9
Seung-Hyun Yoon, John Lewis, Taehyun Rhee
Creating realistic 3D face models is a challenging problem in computer graphics because humans are so sensitive to facial abnormalities. The authors propose a method to synthesize a 3D face model using weighted blending of multiscale details from different face models. Using multiscale continuous displacement maps (CDMs), they achieve full correspondences across multiple scales in the parameter space. Their results demonstrate detail transfer across faces with highly different proportions, such as between humans and nonhuman creatures...
November 2017: IEEE Computer Graphics and Applications
https://www.readbyqxmd.com/read/29140370/mandibular-bone-structure-analysis-using-cone-beam-computed-tomography-vs-primary-implant-stability-an-ex-vivo-study
#10
Ruben Pauwels, Somchai Sessirisombat, Soontra Panmekiate
PURPOSE: To evaluate the relationship between mandibular bone structure parameters measured on preimplant cone beam computed tomography (CBCT) images and primary implant stability. MATERIALS AND METHODS: Twenty-one hemimandibles were scanned on the 3D Accuitomo 170 CBCT. Next, an implant was placed in each hemimandible, after which insertion torque and implant stability quotient (ISQ) measurements were acquired. The following measurements were performed on the preimplant CBCT scans: bone surface, bone volume, fractal dimension, connectivity, trabecular thickness and spacing, and skeleton analysis...
November 2017: International Journal of Oral & Maxillofacial Implants
https://www.readbyqxmd.com/read/29140319/3d-point-cloud-based-apparent-magnitude-model-of-space-objects
#11
Yang Wang, Xiaoping Du
A new 3D-point-cloud-based model is presented for calculating the apparent magnitude of space objects. This model does not consider topological relations of space objects, but it can accurately describe the shape of a space object and calculate its apparent magnitude. Once a 3D point cloud of a space object and its material parameters under a certain wavelength are obtained, the apparent magnitude can be solved. Through this model, the apparent magnitude of space objects with different shapes and the wrinkled surface can be calculated easily...
November 15, 2017: Optics Letters
https://www.readbyqxmd.com/read/29137675/human-hyaluronic-acid-synthase-1-promotes-malignant-transformation-via-epithelial-to-mesenchymal-transition-micronucleation-and-centrosome-abnormalities
#12
Nguyet Nguyen, Awanit Kumar, Simi Chacko, Rodney J Ouellette, Anirban Ghosh
BACKGROUND: Human hyaluronic acid (HA) molecules are synthesized by three membrane spanning Hyaluronic Acid Synthases (HAS1, HAS2 and HAS3). Of the three, HAS1 is found to be localized more into the cytoplasmic space where it synthesizes intracellular HA. HA is a ubiquitous glycosaminoglycan, mainly present in the extracellular matrix (ECM) and on the cell surface, but are also detected intracellularly. Accumulation of HA in cancer cells, the cancer-surrounding stroma, and ECM is generally considered an independent prognostic factors for patients...
November 14, 2017: Cell Communication and Signaling: CCS
https://www.readbyqxmd.com/read/29136658/community-ecology-in-3d-tensor-decomposition-reveals-spatio-temporal-dynamics-of-large-ecological-communities
#13
Romain Frelat, Martin Lindegren, Tim Spaanheden Denker, Jens Floeter, Heino O Fock, Camilla Sguotti, Moritz Stäbler, Saskia A Otto, Christian Möllmann
Understanding spatio-temporal dynamics of biotic communities containing large numbers of species is crucial to guide ecosystem management and conservation efforts. However, traditional approaches usually focus on studying community dynamics either in space or in time, often failing to fully account for interlinked spatio-temporal changes. In this study, we demonstrate and promote the use of tensor decomposition for disentangling spatio-temporal community dynamics in long-term monitoring data. Tensor decomposition builds on traditional multivariate statistics (e...
2017: PloS One
https://www.readbyqxmd.com/read/29134773/design-and-biological-functionality-of-a-novel-hybrid-ti-6al-4v-hydrogel-system-for-reconstruction-of-bone-defects
#14
Alok Kumar, K C Nune, R D K Misra
We have designed a unique injectable bioactive hydrogel comprising of alginate, gelatin, and nanocrystalline hydroxyapatite and loaded with osteoblasts, with the ability to infiltrate into three-dimensional Ti-6Al-4V scaffolds with interconnected porous architecture, fabricated by electron beam melting (EBM). A two-step crosslinking process using the EDC/NHS and CaCl2 was adopted and found to be effective in the fabrication of cell-loaded hydrogel/Ti-6Al-4V scaffold system. This hybrid Ti-6Al-4V scaffold/hydrogel system was designed for the reconstruction of bone defects, which are difficult to heal in the absence of suitable support materials...
November 14, 2017: Journal of Tissue Engineering and Regenerative Medicine
https://www.readbyqxmd.com/read/29127653/development-of-a-3d-workspace-shoulder-assessment-tool-incorporating-electromyography-and-an-inertial-measurement-unit-a-preliminary-study
#15
Navid Aslani, Siamak Noroozi, Philip Davenport, Richard Hartley, Mihai Dupac, Philip Sewell
Traditional shoulder range of movement (ROM) measurement tools suffer from inaccuracy or from long experimental setup times. Recently, it has been demonstrated that relatively low-cost wearable inertial measurement unit (IMU) sensors can overcome many of the limitations of traditional motion tracking systems. The aim of this study is to develop and evaluate a single IMU combined with an electromyography (EMG) sensor to monitor the 3D reachable workspace with simultaneous measurement of deltoid muscle activity across the shoulder ROM...
November 11, 2017: Medical & Biological Engineering & Computing
https://www.readbyqxmd.com/read/29125413/a-computational-fluid-dynamics-simulation-framework-for-ventricular-catheter-design-optimization
#16
Sofy H Weisenberg, Stephanie C TerMaath, Charlotte N Barbier, Judith C Hill, James A Killeffer
OBJECTIVE Cerebrospinal fluid (CSF) shunts are the primary treatment for patients suffering from hydrocephalus. While proven effective in symptom relief, these shunt systems are plagued by high failure rates and often require repeated revision surgeries to replace malfunctioning components. One of the leading causes of CSF shunt failure is obstruction of the ventricular catheter by aggregations of cells, proteins, blood clots, or fronds of choroid plexus that occlude the catheter's small inlet holes or even the full internal catheter lumen...
November 10, 2017: Journal of Neurosurgery
https://www.readbyqxmd.com/read/29122471/3d-registration-of-mpmri-for-assessment-of-prostate-cancer-focal-therapy
#17
Clément Orczyk, Andrew B Rosenkrantz, Artem Mikheev, Arnauld Villers, Myriam Bernaudin, Samir S Taneja, Samuel Valable, Henry Rusinek
RATIONALE AND OBJECTIVES: This study aimed to assess a novel method of three-dimensional (3D) co-registration of prostate magnetic resonance imaging (MRI) examinations performed before and after prostate cancer focal therapy. MATERIALS AND METHODS: We developed a software platform for automatic 3D deformable co-registration of prostate MRI at different time points and applied this method to 10 patients who underwent focal ablative therapy. MRI examinations were performed preoperatively, as well as 1 week and 6 months post treatment...
November 6, 2017: Academic Radiology
https://www.readbyqxmd.com/read/29121409/image-quality-and-dose-for-a-multi-source-cone-beam-ct-extremity-scanner
#18
Grace Jianan Gang, Wojciech Zbijewski, Mahadevappa Mahesh, Gaurav Thawait, Nathan Packard, John Yorkston, Shadpour Demehri, Jeffrey Harrold Siewerdsen
PURPOSE: This work investigates the dose characteristics and image quality of a multi-source cone-beam CT scanner dedicated for extremity imaging. METHODS: The scanner has an x-ray source with three separate anode-cathode units evenly distributed along the longitudinal direction. A nominal scan protocol fires the three sources sequentially, and a total of 600 projections (200 for each source) are acquired over a source-detector orbit of 210(o) . Dose was measured using a Farmer chamber in three CTDI phantoms stacked end-to-end...
November 9, 2017: Medical Physics
https://www.readbyqxmd.com/read/29117484/carotid-intraplaque-hemorrhage-imaging-with-quantitative-vessel-wall-t1-mapping-technical-development-and-initial-experience
#19
Haikun Qi, Jie Sun, Huiyu Qiao, Shuo Chen, Zechen Zhou, Xinlei Pan, Yishi Wang, Xihai Zhao, Rui Li, Chun Yuan, Huijun Chen
Purpose To develop a three-dimensional (3D) high-spatial-resolution time-efficient sequence for use in quantitative vessel wall T1 mapping. Materials and Methods A previously described sequence, simultaneous noncontrast angiography and intraplaque hemorrhage (SNAP) imaging, was extended by introducing 3D golden angle radial k-space sampling (GOAL-SNAP). Sliding window reconstruction was adopted to reconstruct images at different inversion delay times (different T1 contrasts) for voxelwise T1 fitting. Phantom studies were performed to test the accuracy of T1 mapping with GOAL-SNAP against a two-dimensional inversion recovery (IR) spin-echo (SE) sequence...
November 8, 2017: Radiology
https://www.readbyqxmd.com/read/29116737/osteoinduction-by-foamed-and-3d-printed-calcium-phosphate-scaffolds-effect-of-nanostructure-and-pore-architecture
#20
Albert Barba, Anna Diez-Escudero, Yassine Maazouz, Katrin Rappe, Montserrat Espanol, Edgar Benjamín Montufar, Mar Bonany, Joanna Maria Sadowska, Jordi Guillem-Marti, Caroline Öhman-Mägi, Cecilia Persson, Maria-Cristina Manzanares, Jordi Franch, Maria-Pau Ginebra
Some biomaterials are osteoinductive, i.e., they are able to trigger the osteogenic process by inducing the differentiation of mesenchymal stem cells to the osteogenic lineage. Although the underlying mechanism is still unclear, microporosity and specific surface area (SSA) have been identified as critical factors in the material-associated osteoinduction. However, only sintered ceramics, with a limited range of porosities and SSA, have been analysed so far. In this work we were able to extend this range to the nanoscale, through the foaming and 3D-printing of biomimetic calcium phosphates, obtaining scaffolds with controlled micro and nanoporosity together with a tailored macropore architecture...
November 8, 2017: ACS Applied Materials & Interfaces
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