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Dynamic imaging

Alex I Wiesman, Elizabeth Heinrichs-Graham, Nathan M Coolidge, James E Gehringer, Max J Kurz, Tony W Wilson
Sensory gating (SG) is a phenomenon in which neuronal responses to subsequent similar stimuli are weaker, and is thought to be an important mechanism for preventing excessive environmental stimulation from overloading shared neural resources. Although gating has been demonstrated in multiple sensory systems, the neural dynamics and developmental trajectory underlying SG remain poorly understood. Herein, we adopt a data-driven approach to map the spectro-temporal amplitude and functional connectivity (FC) dynamics that support gating in the somatosensory system (somato-SG) in healthy children and adolescents using magnetoencephalography (MEG)...
October 25, 2016: Journal of Physiology
Xi Chen, Qi Li, Xiao-Xi Kan, Ya-Jie Wang, Yu-Jie Li, Qing Yang, Hong-Bin Xiao, Ying Chen, Xiao-Gang Weng, Wei-Yan Cai, Xiao-Xin Zhu
Metastasis of breast cancer is the vital step for malignant progression. During such a process, hematogenous metastasis is an indispensable approach for the dissemination of cancer cells. A platelet, contributes to hypercoagulable state, and is also identified the crucial factor in the coagulation system for supporting metastasis. Therefore, the relationship of a platelet and a tumor cell plays a critical role in tumor cell metastasis. Consequently, inhibiting tumor cell‑induced platelet aggregation (TCIPA) is recongnized as a crucial target on suppression of tumor metastasis such as aspirin (ASA)...
October 19, 2016: Oncology Reports
Anurag Mishra, Yuanyuan Jiang, Sheryl Roberts, Vasilis Ntziachristos, Gil Gregor Westmeyer
Photoacoustic imaging (PAI) is an attractive imaging modality that can volumetrically map the distribution of photoabsorbing molecules with deeper tissue penetration than multiphoton microscopy. To enable dynamic sensing of divalent cations via PAI, we have engineered a new reversible near infrared probe that is more sensitive to calcium as compared to other biologically relevant cations. The metallochromic compound showed a strong reduction of its peak absorbance at 765 nm upon addition of calcium ions that was translated into robust signal changes in photoacoustic images...
October 25, 2016: Analytical Chemistry
Edward Taylor, Ivan Yeung, Harald Keller, Bradley G Wouters, Michael Milosevic, David W Hedley, David A Jaffray
Compared to FDG, the signal of (18)F-labelled hypoxia-sensitive tracers in tumours is low. This means that in addition to the presence of hypoxic cells, transport properties contribute significantly to the uptake signal in static PET images. This sensitivity to transport must be minimized in order for static PET to provide a reliable standard for hypoxia quantification. A dynamic compartmental model based on a reaction-diffusion formalism was developed to interpret tracer pharmacokinetics and applied to static images of FAZA in twenty patients with pancreatic cancer...
November 21, 2016: Physics in Medicine and Biology
Jannetta S Steyn, Peter Andras
The temporal relationship between the activities of neurons in biological neural systems is critically important for the correct delivery of the functionality of these systems. Fine measurement of temporal relationships of neural activities using micro-electrodes is possible but this approach is very limited due to spatial constraints in the context of physiologically valid settings of neural systems. Optical imaging with voltage-sensitive dyes or calcium dyes can provide data about the activity patterns of many neurons in physiologically valid settings, but the data is relatively noisy...
October 24, 2016: Journal of Computational Neuroscience
Sanjeev Kakar, Ryan E Breighner, Shuai Leng, Cynthia H McCollough, Steven L Moran, Richard A Berger, Kristin D Zhao
Background Scapholunate (SL) interosseus ligament injuries detected at an early stage could allow the surgeon to prevent progression through the spectrum of injury that leads to instability, and eventually osteoarthritis. We contend that early instability following injury can be detected by visualizing the relative motions and distances between the involved carpal bones (scaphoid and lunate) during wrist movement in vivo. The purpose of this study is to demonstrate the utility of dynamic CT (i.e., 4DCT) in diagnosing SL interosseus ligament injuries in two patients with clinical suspicion of SL interosseus ligament injury during flexion-extension (FE), radial-ulnar (RU) deviation, and dart thrower's (DT) motions...
November 2016: Journal of Wrist Surgery
Sarah L Richardson, Pawel Swietach
During capillary transit, red blood cells (RBCs) must exchange large quantities of CO2 and O2 in typically less than one second, but the degree to which this is rate-limited by diffusion through cytoplasm is not known. Gas diffusivity is intuitively assumed to be fast and this would imply that the intracellular path-length, defined by RBC shape, is not a factor that could meaningfully compromise physiology. Here, we evaluated CO2 diffusivity (DCO2) in RBCs and related our results to cell shape. DCO2 inside RBCs was determined by fluorescence imaging of [H(+)] dynamics in cells under superfusion...
October 25, 2016: Scientific Reports
Anna C Lawson McLean, Steffen K Rosahl
OBJECT: Neurofibromatosis type 2 is an autosomal-dominant disorder caused by a defective gene locus 22q12. Patients with NF2 are prone to develop multiple intracranial neoplasms, such as vestibular schwannomas, meningiomas and schwannomas of other cranial nerves. To date, little is known about the growth dynamics of these tumors. The aim of our study was to investigate a) the median growth rate per year, b) the growth-free intervals, and c) the growth patterns of these tumors. METHODS: Patient records from the regional neurofibromatosis center were evaluated for their suitability in this analysis...
October 21, 2016: World Neurosurgery
Athina M Mavridou, Esther Hauben, Martine Wevers, Evert Schepers, Lars Bergmans, Paul Lambrechts
INTRODUCTION: The aim of this study was to investigate the 3-dimensional (3D) structure and the cellular and tissue characteristics of external cervical resorption (ECR) in vital teeth and to understand the phenomenon of ECR by combining histomorphological and radiographic findings. METHODS: Twenty-seven cases of vital permanent teeth displaying ECR were investigated. ECR diagnosis was based on clinical and radiographic examination with cone-beam computed tomographic imaging...
October 21, 2016: Journal of Endodontics
Roberto Sanz-Requena, Luis Martí-Bonmatí, Rosario Pérez-Martínez, Gracián García-Martí
PURPOSE: The aim of this work is to establish normality and tumor tissue ranges for perfusion parameters from dynamic contrast-enhanced (DCE) MR of the peripheral prostate at 3T and to compare the diagnostic performance of quantitative and semi-quantitative parameters. MATERIALS AND METHODS: Thirty-six patients with prostate carcinomas (18 Gleason-6, 15 Gleason-7, and 3 Gleason-8) and 33 healthy subjects were included. Image analysis workflow comprised four steps: manual segmentation of whole prostate and lesions, series registration, voxelwise T1 mapping and calculation of pharmacokinetic and semi-quantitative parameters...
November 2016: European Journal of Radiology
X Wang, T Henzler, J Gawlitza, S Diehl, T Wilhelm, S O Schoenberg, Z Y Jin, H D Xue, A Smakic
PURPOSE: Dynamic volume perfusion CT (dVPCT) provides valuable information on tissue perfusion in patients with hepatocellular carcinoma (HCC) and pancreatic cancer. However, currently dVPCT is often performed in addition to conventional CT acquisitions due to the limited morphologic image quality of dose optimized dVPCT protocols. The aim of this study was to prospectively compare objective and subjective image quality, lesion detectability and radiation dose between mean temporal arterial (mTA) and mean temporal portal venous (mTPV) images calculated from low dose dynamic volume perfusion CT (dVPCT) datasets with linearly blended 120-kVp arterial and portal venous datasets in patients with HCC and pancreatic cancer...
November 2016: European Journal of Radiology
Frederike Alwes, Camille Enjolras, Michalis Averof
Regeneration is a complex and dynamic process, mobilizing diverse cell types and remodelling tissues over long time periods. Tracking cell fate and behaviour during regeneration in active adult animals is especially challenging. Here, we establish continuous live imaging of leg regeneration at single-cell resolution in the crustacean Parhyale hawaiensis. By live recordings encompassing the first 4-5 days after amputation, we capture the cellular events that contribute to wound closure and morphogenesis of regenerating legs with unprecedented resolution and temporal detail...
October 25, 2016: ELife
Dean R Freestone, Kelvin J Layton, Levin Kuhlmann, Mark J Cook
Data-driven model-based analysis of electrophysiological data is an emerging technique for understanding the mechanisms of seizures. Model-based analysis enables tracking of hidden brain states that are represented by the dynamics of neural mass models. Neural mass models describe the mean firing rates and mean membrane potentials of populations of neurons. Various neural mass models exist with different levels of complexity and realism. An ideal data-driven model-based analysis framework will incorporate the most realistic model possible, enabling accurate imaging of the physiological variables...
June 9, 2016: International Journal of Neural Systems
Zhuochen Wang, Karl Heath Martin, Wenbin Huang, Paul A Dayton, Xiaoning Jiang
Techniques to image the microvasculature may play an important role in imaging tumor-related angiogenesis and vasa vasorum associated with vulnerable atherosclerotic plaques. However, the microvasculature associated with these pathologies is difficult to detect using traditional B-mode ultrasound or even harmonic imaging due to small vessel size and poor differentiation from surrounding tissue. Acoustic angiography, a microvascular imaging technique which utilizes superharmonic imaging (detection of higher order harmonics of microbubble response), can yield a much higher contrast to tissue ratio (CTR) than second harmonic imaging methods...
October 20, 2016: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
Brennan S Dirk, Logan R Van Nynatten, Jimmy D Dikeakos
Viruses must continuously evolve to hijack the host cell machinery in order to successfully replicate and orchestrate key interactions that support their persistence. The type-1 human immunodeficiency virus (HIV-1) is a prime example of viral persistence within the host, having plagued the human population for decades. In recent years, advances in cellular imaging and molecular biology have aided the elucidation of key steps mediating the HIV-1 lifecycle and viral pathogenesis. Super-resolution imaging techniques such as stimulated emission depletion (STED) and photoactivation and localization microscopy (PALM) have been instrumental in studying viral assembly and release through both cell-cell transmission and cell-free viral transmission...
October 19, 2016: Viruses
Ren-Feng Ding, Chih-Wen Yang, Kuang-Yuh Huang, Ing-Shouh Hwang
In the operation of a dynamic mode atomic force microscope, a micro-fabricated rectangular cantilever is typically oscillated at or near its mechanical resonance frequency. Lateral bending resonances of cantilevers are rarely used because the resonances are not expected to be detected by the beam-deflection method. In this work, we found that micro-cantilevers with a large tip produced an out-of-plane displacement in lateral resonance (LR), which could be detected with the beam-deflection method. Finite-element analysis indicated that the presence of a large tip is the major source of the out-of-plane coupling for the LR...
October 24, 2016: Nanoscale
Ying-Feng Hsu, Yu-Hsun Chen, Chih-Wei Chang
We performed comprehensive studies on the photoluminescence properties of the carbon dots prepared from citric acid (C-dots(CA)) and citric acid + ethylenediamine (C-dots(CA+EDA)). The cryogenic experiment confirmed that the excitation dependent fluorescence and the spectral relaxation dynamics of the C-dots are associated with the presence of multiple emissive states/species in the C-dots instead of solvation dynamics. Moreover, we also compared the size of the C-dots estimated from the TEM/AFM images and fluorescence anisotropy methods...
October 24, 2016: Physical Chemistry Chemical Physics: PCCP
Timothy K Lee, Kevin Meng, Handuo Shi, Kerwyn Casey Huang
The peptidoglycan cell wall is an integral organelle critical for bacterial cell shape and stability. Proper cell wall construction requires the interaction of synthesis enzymes and the cytoskeleton, but it is unclear how the activities of individual proteins are coordinated to preserve the morphology and integrity of the cell wall during growth. To elucidate this coordination, we used single-molecule imaging to follow the behaviours of the two major peptidoglycan synthases in live, elongating Escherichia coli cells and after perturbation...
October 24, 2016: Nature Communications
Yuanhua Qiao, Xiaojie Liu, Jun Miao, Lijuan Duan
In this paper, a two-layer network is built to simulate the mechanism of visual selection and shifting based on the mapping dynamic model for instantaneous frequency. Unlike the differential equation model using limit cycle to simulate neuron oscillation, we build an instantaneous frequency mapping dynamic model to describe the change of the neuron frequency to avoid the difficulty of generating limit cycle. The activity of the neuron is rebuilt based on the instantaneous frequency and in this work, we use the first layer of neurons to implement image segmentation and the second layer of neurons to act as visual selector...
October 24, 2016: Journal of Integrative Neuroscience
Orso Pusterla, Grzegorz Bauman, Mark O Wielpütz, Sylvia Nyilas, Philipp Latzin, Claus P Heussel, Oliver Bieri
PURPOSE: To introduce a reproducible, nonenhanced 1H MRI method for rapid in vivo functional assessment of the whole lung at 1.5 Tesla (T). METHODS: At different respiratory volumes, the pulmonary signal of ultra-fast steady-state free precession (ufSSFP) follows an adapted sponge model, characterized by a respiratory index α. From the model, α reflects local ventilation-related information, is virtually independent from the lung density and thus from the inspiratory phase and breathing amplitude...
October 23, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
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