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optical flow

Qiu Hong Cui, Qian Peng, Yi Luo, Yuqian Jiang, Yongli Yan, Cong Wei, Zhigang Shuai, Cheng Sun, Jiannian Yao, Yong Sheng Zhao
The ability to steer the flow of light toward desired propagation directions is critically important for the realization of key functionalities in optical communication and information processing. Although various schemes have been proposed for this purpose, the lack of capability to incorporate an external electric field to effectively tune the light propagation has severely limited the on-chip integration of photonics and electronics. Because of the noninteractive nature of photons, it is only possible to electrically control the flow of light by modifying the refractive index of materials through the electro-optic effect...
March 2018: Science Advances
Alisa Javadi, Dapeng Ding, Martin Hayhurst Appel, Sahand Mahmoodian, Matthias Christian Löbl, Immo Söllner, Rüdiger Schott, Camille Papon, Tommaso Pregnolato, Søren Stobbe, Leonardo Midolo, Tim Schröder, Andreas Dirk Wieck, Arne Ludwig, Richard John Warburton, Peter Lodahl
The spin of an electron is a promising memory state and qubit. Connecting spin states that are spatially far apart will enable quantum nodes and quantum networks based on the electron spin. Towards this goal, an integrated spin-photon interface would be a major leap forward as it combines the memory capability of a single spin with the efficient transfer of information by photons. Here, we demonstrate such an efficient and optically programmable interface between the spin of an electron in a quantum dot and photons in a nanophotonic waveguide...
March 19, 2018: Nature Nanotechnology
J P R Sorensen, A Vivanco, M J Ascott, D C Gooddy, D J Lapworth, D S Read, C M Rushworth, J Bucknall, K Herbert, I Karapanos, L P Gumm, R G Taylor
We assessed the utility of online fluorescence spectroscopy for the real-time evaluation of the microbial quality of untreated drinking water. Online fluorimeters were installed on the raw water intake at four groundwater-derived UK public water supplies alongside existing turbidity sensors that are used to forewarn of the presence of microbial contamination in the water industry. The fluorimeters targeted fluorescent dissolved organic matter (DOM) peaks at excitation/emission wavelengths of 280/365 nm (tryptophan-like fluorescence, TLF) and 280/450 nm (humic-like fluorescence, HLF)...
March 3, 2018: Water Research
Roger A Goldberg, Katherine M Raja
The retinal lesion known as the presumed solitary circumscribed retinal astrocytic proliferation (pSCRAP) is a benign retinal tumor. Although many of the clinical characteristics of the lesion have been described, much about the pathogenesis of this uncommon tumor is not yet known. Here, the authors report a pSCRAP lesion in the fovea with secondary vision loss occurring in middle age. Structural optical coherence tomography (OCT) scans indicate that the lesion arises from the deep retina or retinal pigment epithelium (RPE), whereas OCT angiography characteristics of the lesion show a lack of intrinsic or paralesional vascular flow, indicating that this lesion is fibrous and likely derived from the RPE or deep retina and not the retinal astrocytes...
March 1, 2018: Ophthalmic Surgery, Lasers & Imaging Retina
Anna Dastiridou, Vikas Chopra
PURPOSE OF REVIEW: Optical coherence tomography angiography (OCTA) is a novel, noninvasive imaging modality that allows assessment of the retinal and choroidal vasculature. The scope of this review is to summarize recent studies using OCTA in glaucoma and highlight potential applications of this new technology in the field of glaucoma. RECENT FINDINGS: OCTA studies have shown that retinal vascular changes may not develop solely as a result of advanced glaucoma damage...
March 15, 2018: Current Opinion in Ophthalmology
Paolo Giuseppe Limoli, Enzo Maria Vingolo, Celeste Limoli, Sergio Zaccaria Scalinci, Marcella Nebbioso
This study is aimed at examining whether a suprachoroidal graft of autologous cells can improve best corrected visual acuity (BCVA) and responses to microperimetry (MY) in eyes affected by dry Age-related Macular Degeneration (AMD) over time through the production and secretion of growth factors (GFs) on surrounding tissue. Patients were randomly assigned to each study group. All patients were diagnosed with dry AMD and with BCVA equal to or greater than 1 logarithm of the minimum angle of resolution (logMAR)...
February 12, 2018: Journal of Visualized Experiments: JoVE
Karthik Vishwanath, Rajan Gurjar, David Wolf, Suzannah Riccardi, Michael Duggan, David King
Reliable, continuous and noninvasive blood flow and hemoglobin monitoring in trauma patients remains a critical, but generally unachieved goal. Two optical sensing methods - diffuse correlation spectroscopy (DCS) and diffuse reflectance spectroscopy (DRS) - are used to monitor and detect internal hemorrhage. Specifically, we investigate if cutaneous perfusion measurements acquired using DCS and DRS in peripheral (thighs and ear-lobe) tissues could detect severe hemorrhagic shock in a porcine model. Four animals underwent high-grade hepato-portal injury in a closed abdomen, to induce uncontrolled hemorrhage and were subsequently allowed to bleed for 10 minutes before fluid resuscitation...
February 1, 2018: Biomedical Optics Express
Boy Braaf, Sabine Donner, Ahhyun S Nam, Brett E Bouma, Benjamin J Vakoc
Complex differential variance (CDV) provides phase-sensitive angiographic imaging for optical coherence tomography (OCT) with immunity to phase-instabilities of the imaging system and small-scale axial bulk motion. However, like all angiographic methods, measurement noise can result in erroneous indications of blood flow that confuse the interpretation of angiographic images. In this paper, a modified CDV algorithm that corrects for this noise-bias is presented. This is achieved by normalizing the CDV signal by analytically derived upper and lower limits...
February 1, 2018: Biomedical Optics Express
Masoud Ghader, Nader Shokoufi, Ali Es-Haghi, Kazem Kargosha
Vaccine production is a biological process in which variation in time and output is inevitable. Thus, the application of Process Analytical Technologies (PAT) will be important in this regard. Headspace solid - phase microextraction (HS-SPME) coupled with GC-MS can be used as a PAT for process monitoring. This method is suitable to chemical profiling of volatile organic compounds (VOCs) emitted from microorganisms. Tetanus is a lethal disease caused by Clostridium tetani (C. tetani) bacterium and vaccination is an ultimate way to prevent this disease...
February 6, 2018: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
Gaole Dai, Jin Shang, Jiping Huang
Heat can transfer via thermal conduction, thermal radiation, and thermal convection. All the existing theories of transformation thermotics and optics can treat thermal conduction and thermal radiation, respectively. Unfortunately, thermal convection has seldom been touched in transformation theories due to the lack of a suitable theory, thus limiting applications associated with heat transfer through fluids (liquid or gas). Here, we develop a theory of transformation thermal convection by considering the convection-diffusion equation, the equation of continuity, and the Darcy law...
February 2018: Physical Review. E
Ben Lertsakdadet, Bruce Y Yang, Cody E Dunn, Adrien Ponticorvo, Christian Crouzet, Nicole Bernal, Anthony J Durkin, Bernard Choi
Laser speckle imaging (LSI) is a wide-field optical technique that enables superficial blood flow quantification. LSI is normally performed in a mounted configuration to decrease the likelihood of motion artifact. However, mounted LSI systems are cumbersome and difficult to transport quickly in a clinical setting for which portability is essential in providing bedside patient care. To address this issue, we created a handheld LSI device using scientific grade components. To account for motion artifact of the LSI device used in a handheld setup, we incorporated a fiducial marker (FM) into our imaging protocol and determined the difference between highest and lowest speckle contrast values for the FM within each data set (Kbest and Kworst)...
March 2018: Journal of Biomedical Optics
Elizabeth A MacDonald, Eric Donovan, Yukitoshi Nishimura, Nathan A Case, D Megan Gillies, Bea Gallardo-Lacourt, William E Archer, Emma L Spanswick, Notanee Bourassa, Martin Connors, Matthew Heavner, Brian Jackel, Burcu Kosar, David J Knudsen, Chris Ratzlaff, Ian Schofield
A glowing ribbon of purple light running east-west in the night sky has recently been observed by citizen scientists. This narrow, subauroral, visible structure, distinct from the traditional auroral oval, was largely undocumented in the scientific literature and little was known about its formation. Amateur photo sequences showed colors distinctly different from common types of aurora and occasionally indicated magnetic field-aligned substructures. Observations from the Swarm satellite as it crossed the arc have revealed an unusual level of electron temperature enhancement and density depletion, along with a strong westward ion flow, indicating that a pronounced subauroral ion drift (SAID) is associated with this structure...
March 2018: Science Advances
Marion Bienert, Niklas Plange, Andreas Remky, Kay Oliver Arend, David Kuerten
Purpose: Ischemic ocular disorders may be treated by hypervolemic hemodilution. The presumed therapeutic benefit is based on a volume effect and improved rheological factors. The aim was to investigate the acute effect of intravenous hydroxyethyl starch on retrobulbar hemodynamics in patients with nonarteritic anterior ischemic optic neuropathy (NAION). Methods: 24 patients with acute NAION were included. Retrobulbar hemodynamics were measured using color Doppler imaging before and 15 min after intravenous infusion of 250 cc 10% hydroxyethyl starch (HES)...
2018: BioMed Research International
Mathias Reisbeck, Lukas Richter, Michael Johannes Helou, Stephan Arlinghaus, Birgit Anton, Ignas van Dommelen, Mario Nitzsche, Michael Baßler, Barbara Kappes, Oliver Friedrich, Oliver Hayden
Time-of-flight (TOF) magnetic sensing of rolling immunomagnetically-labeled cells offers great potential for single cell function analysis at the bedside in even optically opaque media, such as whole blood. However, due to the spatial resolution of the sensor and the low flow rate regime required to observe the behavior of rolling cells, the concentration range of such a workflow is limited. Potential clinical applications, such as testing of leukocyte function, require a cytometer which can cover a cell concentration range of several orders of magnitude...
March 12, 2018: Biosensors & Bioelectronics
Jeffrey C Liu, Peter L Nesper, Amani A Fawzi, Manjot K Gill
Purpose: We report a case of acute macular neuroretinopathy (AMN) following routine annual inactivated influenza vaccination. Projection-resolved optical coherence tomography angiography (PR-OCTA) was used to analyze the retinal capillary flow within the AMN lesion. Observations: Our patient reported visual symptoms of her right eye nine days after routine annual influenza vaccination. Multimodal imaging revealed small vessel peripheral vasculitis and AMN in the affected eye...
June 2018: American Journal of Ophthalmology Case Reports
Raquel Delgado-Mederos, Clara Gregori-Pla, Peyman Zirak, Igor Blanco, Lavinia Dinia, Rebeca Marín, Turgut Durduran, Joan Martí-Fàbregas
In this pilot study, we have evaluated bedside diffuse optical monitoring combining diffuse correlation spectroscopy and near-infrared diffuse optical spectroscopy to assess the effect of thrombolysis with an intravenous recombinant tissue plasminogen activator (rtPA) on cerebral hemodynamics in an acute ischemic stroke. Frontal lobes of five patients with an acute middle cerebral artery occlusion were measured bilaterally during rtPA treatment. Both ipsilesional and contralesional hemispheres showed significant increases in cerebral blood flow, total hemoglobin concentration and oxy-hemoglobin concentration during the first 2...
March 1, 2018: Biomedical Optics Express
Zaineb Al-Qazwini, Zhen Yu Gordon Ko, Kalpesh Mehta, Nanguang Chen
We report an ultrahigh-speed and high-resolution line-scan spectral-domain optical coherence tomography (SD-OCT) system that integrates a number of mechanisms for improving image quality. The illumination uniformity is significantly improved by the use of a Powell lens; Phase stepping and differential reconstruction are combined to suppress autocorrelation artifacts; Nonlocal means (NLM) is employed to enhance the signal to noise ratio while minimizing motion artifacts. The system is capable of acquiring cross-sectional images at more than 3,500 B-scans per second with sensitivities between 70dB and 90dB...
March 1, 2018: Biomedical Optics Express
Eric W Schneider, Samuel C Fowler
PURPOSE OF REVIEW: Optical coherence tomography angiography (OCT-A) provides rapid, flow-based imaging of the retinal and choroidal vasculature in a noninvasive manner. This review contrasts this novel technique with conventional angiography and discusses its current uses and limitations in the management of age-related macular degeneration (AMD). RECENT FINDINGS: Initial work with OCT-A has focused on its ability to identify choriocapillaris flow alterations in dry AMD and to sensitively detect choroidal neovascular membranes (CNVs) in neovascular AMD...
March 13, 2018: Current Opinion in Ophthalmology
Koushun Kamada, Ryousuke Tachibanagi, Hideki Nakagawa
Toads on the ground control landing behavior by a simple strategy in which they extend their elbows at roughly the same time after take-off and continue extending them at the same velocity until they land. However, this simple strategy does not work well in much more complicated arboreal habitat. We analyzed properties of jumping and timing of forelimb extension of the tree frog, Hyla japonica, to demonstrate how the arboreal species land safely. The results showed that distance, duration, and velocity of jump were not affected by explicit optic flow information, whereas the all three parameters decreased significantly in the blindfolded animals...
March 13, 2018: Journal of Experimental Zoology. Part A, Ecological and Integrative Physiology
Maudy Walraven, Marjolein Y V Homs, Astrid A M van der Veldt, Henk Dekker, Jose Koldenhof, Richard Honeywell, Arjan Barendrecht, Silvie A E Sebastian, Naomi Parr, Arnold C Koekman, Emile E Voest, Mark Roest, Suzanne J A Korporaal, Henk M W Verheul
INTRODUCTION: At the clinical introduction of antiangiogenic agents as anticancer agents, no major toxicities were expected as merely just endothelial cells (ECs) in tumors would be affected. However, several (serious) toxicities became apparent, of which underlying mechanisms are largely unknown. We investigated to what extent sunitinib (multitargeted antiangiogenic tyrosine kinase inhibitor (TKI)), sorafenib (TKI) and bevacizumab [specific antibody against vascular endothelial growth factor (VEGF)] may impair platelet function, which might explain treatment-related bleedings...
March 12, 2018: Angiogenesis
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