15,754 results match your criteria optical depth


Super-Resolution Defocusing Nanoparticle Image Velocimetry Utilizing Spherical Aberration for Nanochannel Flows.

Anal Chem 2021 Sep 24. Epub 2021 Sep 24.

Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656, Japan.

Understanding fluid flows and mass transport in nanospaces is becoming important with recent advances in nanofluidic analytical devices utilizing nanopores and nanochannels. In the present study, we developed a super-resolution and fast particle tracking method utilizing defocusing images with spherical aberration and demonstrated the measurement of nanochannel flow. Since the spherical aberration generates the defocusing nanoparticle image with diffraction rings, the position of fluorescent nanoparticles was determined from the radius of the diffraction ring. Read More

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September 2021

Molecular Probes for Autofluorescence-Free Optical Imaging.

Chem Rev 2021 Sep 24. Epub 2021 Sep 24.

School of Chemical and Biomedical Engineering, Nanyang Technological University, 70 Nanyang Drive, Singapore 637457, Singapore.

Optical imaging is an indispensable tool in clinical diagnostics and fundamental biomedical research. Autofluorescence-free optical imaging, which eliminates real-time optical excitation to minimize background noise, enables clear visualization of biological architecture and physiopathological events deep within living subjects. Molecular probes especially developed for autofluorescence-free optical imaging have been proven to remarkably improve the imaging sensitivity, penetration depth, target specificity, and multiplexing capability. Read More

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September 2021

Pachychoroid Spectrum Disorder Findings in Patients with Coronavirus Disease 2019.

Case Rep Ophthalmol Med 2021 13;2021:4688764. Epub 2021 Sep 13.

Eye Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.

Purpose: To report the occurrence of acute, bilateral, central serous chorioretinopathy (CSC), and pachychoroid spectrum disorder findings in patients with coronavirus disease 2019 (COVID-19).

Methods: In recovered cases of COVID-19 with visual disturbances, complete ocular examinations with multimodal retinal and choroidal evaluation, including enhanced depth imaging optical coherence tomography, fluorescein or indocyanine green angiography, and blue autofluorescence, were obtained.

Results: Four COVID-19 recovered patients presented with bilateral blurred vision. Read More

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September 2021

In vivo examination of healthy human skin after short-time treatment with moisturizers using confocal Raman spectroscopy and optical coherence tomography: Preliminary observations.

Skin Res Technol 2021 Sep 23. Epub 2021 Sep 23.

Department of Dermatology and Allergy, University Hospital, Ludwig Maximilian University, Munich, Germany.

Skin is our barrier against environmental damage. Moisturizers are widely used to increase hydration and barrier integrity of the skin; however, there are contrasting observations on their in vivo effects in real-life settings. In cosmetic studies, corneometers and tewameters are traditionally used to assess skin hydration. Read More

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September 2021

Choroidal features in flat irregular pigment epithelial detachment associated with Chronic central serous chorioretinopathy: Avascular versus vascularized.

PLoS One 2021 23;16(9):e0257763. Epub 2021 Sep 23.

Retina Service, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran.

Purpose: To investigate the differences in the choroidal biomarkers between two forms of flat irregular pigment epithelial detachment (FIPED): avascular (aFIPED) and vascularized (vFIPED) in eyes with chronic central serous chorioretinopathy (CSC).

Materials And Methods: Enhanced depth imaging optical coherence tomography (EDI-OCT) was done in eyes with FIPED correlated to chronic CSC, fellow eyes, and also in healthy eyes from gender- and age-matched subjects. Eyes with FIPED were classified into two subgroups based on optical coherence tomography angiography (OCTA) findings: vFIPED and aFIPED. Read More

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September 2021

In Vivo Near-Infrared Imaging Using Ternary Selenide Semiconductor Nanoparticles with an Uncommon Crystal Structure.

Small 2021 Sep 23:e2103505. Epub 2021 Sep 23.

Nanomaterials for Bioimaging Group (NanoBIG), Facultad de Ciencias, Universidad Autónoma de Madrid, C/Francisco Tomás y Valiente 7, Madrid, 28049, Spain.

The implementation of in vivo fluorescence imaging as a reliable diagnostic imaging modality at the clinical level is still far from reality. Plenty of work remains ahead to provide medical practitioners with solid proof of the potential advantages of this imaging technique. To do so, one of the key objectives is to better the optical performance of dedicated contrast agents, thus improving the resolution and penetration depth achievable. Read More

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September 2021

High resolution, programmable aperture light field laparoscope for quantitative depth mapping.

OSA Contin 2020 Feb;3(2):194-203

3D visualization and imaging system laboratory, College of Optical Sciences, University of Arizona, 1630 E University Blvd., Tucson, AZ 85721, USA.

Recent applications have shown that light field imaging can be useful for developing uniaxial three-dimensional (3D) endoscopes. The immediate challenges in implementation are a tradeoff in lateral resolution and acquiring enough depth information in the physically limited environment of minimally invasive surgery. Here we propose using programmable aperture light field imaging in laparoscopy to capture 3D information without sacrificing the camera sensor's native, high spatial resolution. Read More

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February 2020

Coherent Raman scattering imaging with a near-infrared achromatic metalens.

APL Photonics 2021 Sep 14;6(9):096107. Epub 2021 Sep 14.

John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA.

Miniature handheld imaging devices and endoscopes based on coherent Raman scattering are promising for label-free optical diagnosis. Toward the development of these small-scale systems, a challenge arises from the design and fabrication of achromatic and high-end miniature optical components for both pump and Stokes laser wavelengths. Here, we report a metasurface converting a low-cost plano-convex lens into a water-immersion, nearly diffraction-limited and achromatic lens. Read More

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September 2021

Visualizing the Invisible: Advanced Optical Microscopy as a Tool to Measure Biomechanical Forces.

Front Cell Dev Biol 2021 6;9:706126. Epub 2021 Sep 6.

Advanced Imaging Center, Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, United States.

The importance of mechanical force in biology is evident across diverse length scales, ranging from tissue morphogenesis during embryo development to mechanotransduction across single adhesion proteins at the cell surface. Consequently, many force measurement techniques rely on optical microscopy to measure forces being applied by cells on their environment, to visualize specimen deformations due to external forces, or even to directly apply a physical perturbation to the sample via photoablation or optogenetic tools. Recent developments in advanced microscopy offer improved approaches to enhance spatiotemporal resolution, imaging depth, and sample viability. Read More

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September 2021

Molecular Design of Ultrabright Semiconducting Polymer Dots with High NIR-II Fluorescence for 3D Tumor Mapping.

Adv Healthc Mater 2021 Sep 22:e2100993. Epub 2021 Sep 22.

Department of Applied Chemistry, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan.

Fluorescence probes emitting in the second near-infrared (NIR-II, 1000-1700 nm) window with the ability for deep-tissue imaging in mammals herald a new era in surgical methodology. However, the brightness of these NIR-II probes is still far from satisfactory due to their low fluorescence quantum yields (QYs), preventing the observation of high-resolution images such as whole-organ vascular networks in real time. Described here is the molecular engineering of a series of semiconducting polymer dots (Pdots) incorporated with aggregation-induced emission moieties to exhibit the QYs as high as 14% in the NIR-II window. Read More

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September 2021

Estimating PM concentrations in Northeastern China with full spatiotemporal coverage, 2005-2016.

Remote Sens Environ 2021 Feb 2;253. Epub 2020 Dec 2.

Gangarosa Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA, USA.

Predicting long-term spatiotemporal characteristics of fine particulate matter (PM) is important in China to understand historical levels of PM, to support health effects research of both long-term and short-term exposures to PM, and to evaluate the efficacy of air pollution control policies. Satellite-retrieved aerosol optical depth (AOD) provides a unique opportunity to characterize the long-term trends of ground-level PM at high spatial resolution. However, the missing rate of AOD in Northeastern China (NEC) is very high, especially in winter, and challenges the accuracy of long-term predictions of PM if left unresolved. Read More

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February 2021

Bifocal 532/1064 nm alternately illuminated photoacoustic microscopy for capturing deep vascular morphology in human skin.

J Eur Acad Dermatol Venereol 2021 Sep 21. Epub 2021 Sep 21.

MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou, 510631, China.

Background: As a promising technology, photoacoustic microscopy (PAM) plays a critical role in diagnosis and assessment of dermatological conditions by providing subtle vascular networks noninvasively. However, the established PAMs are insufficient for clinical dermatology when faced with complex structures of human skin instead of animal models owing to high melanin content and superimposed vasculature for Asians, which cannot balance the spatial resolution and the imaging depth.

Objectives: To evaluate the ability of bifocal 532/1064-nm alternately illuminated photoacoustic microscopy (BF-PAM) to non-invasively reveal the morphological structure of human skin for improving the diagnosis and therapeutic efficacy of skin diseases. Read More

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September 2021

Estimation of diffuse Cherenkov optical emission from external beam radiation build-up in tissue.

J Biomed Opt 2021 Sep;26(9)

Thayer School of Engineering at Dartmouth, Dartmouth College, United States.

Significance: Optical imaging of Cherenkov emission during radiation therapy could be used to verify dose delivery in real-time if a more comprehensive quantitative understanding of the factors affecting emission intensity could be developed.

Aim: This study aims to explore the change in diffuse Cherenkov emission intensity with x-ray beam energy from irradiated tissue, both theoretically and experimentally.

Approach: Derivation of the emitted Cherenkov signal was achieved using diffusion theory, and experimental studies with 6 to 18 MV energy x-rays were performed in tissue phantoms to confirm the model predictions as related to the radiation build-up factor with depth into tissue. Read More

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September 2021

Individual exposure to ambient PM and hospital admissions for COPD in 110 hospitals: a case-crossover study in Guangzhou, China.

Environ Sci Pollut Res Int 2021 Sep 21. Epub 2021 Sep 21.

National Clinical Research Center for Kidney Disease, State Key Laboratory of Organ Failure Research, Department of Biostatistics, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, 510515, China.

Few studies have evaluated the short-term association between hospital admissions and individual exposure to ambient particulate matter (PM). Particularly, no studies focused on hospital admissions for chronic obstructive pulmonary disease (COPD) at the individual level. We assessed the short-term effects of PM on hospitalization admissions for COPD in Guangzhou, China, during 2014-2015, based on satellite-derived estimates of ambient PM concentrations at a 1-km resolution near the residential address as individual-level exposure for each patient. Read More

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September 2021

Red Fluorescent Emissive Gd-Phenolic Nanoparticles for Fluorescence and Magnetic Resonance Bimodal Imaging.

J Biomed Nanotechnol 2021 Aug;17(8):1635-1646

College of Science, Gansu Agricultural University, Lanzhou 730000, China.

Due to the combination of the high resolution of fluorescence imaging and the no limitation in penetration depth of magnetic resonance imaging, dual-mode imaging of magnetic resonance and fluorescence (MR/FI) have attracted extensive research in recent years. Herein, a novel MR/FI bimodal imaging probe is facile fabricated by attaching the rhodamine fluorophore covalently to the surface of the Gd-phenolic coordination polymer nanoparticles. The contents of Gd and RB of the as prepared probe are calculated to be 8. Read More

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The role of interferon regulatory factor 8 for retinal tissue homeostasis and development of choroidal neovascularisation.

J Neuroinflammation 2021 Sep 20;18(1):215. Epub 2021 Sep 20.

Medical Faculty, Eye Center, University Hospital, University of Freiburg, Freiburg im Breisgau, Germany.

Background: Microglia cells represent the resident innate immune cells of the retina and are important for retinal development and tissue homeostasis. However, dysfunctional microglia can have a negative impact on the structural and functional integrity of the retina under native and pathological conditions.

Methods: In this study, we examined interferon-regulatory factor 8 (Irf8)-deficient mice to determine the transcriptional profile, morphology, and temporospatial distribution of microglia lacking Irf8 and to explore the effects on retinal development, tissue homeostasis, and formation of choroidal neovascularisation (CNV). Read More

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September 2021

Estimating monthly PM concentrations from satellite remote sensing data, meteorological variables, and land use data using ensemble statistical modeling and a random forest approach.

Environ Pollut 2021 Sep 14;291:118159. Epub 2021 Sep 14.

Institute of Environmental and Occupational Health Sciences, School of Public Health, National Taiwan University, Taiwan. Electronic address:

Fine particulate matter (PM) is associated with various adverse health outcomes and poses serious concerns for public health. However, ground monitoring stations for PM measurements are mostly installed in population-dense or urban areas. Thus, satellite retrieved aerosol optical depth (AOD) data, which provide spatial and temporal surrogates of exposure, have become an important tool for PM estimates in a study area. Read More

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September 2021

Characteristics of the severe March 2021 Gobi Desert dust storm and its impact on air pollution in China.

Chemosphere 2021 Sep 14;287(Pt 3):132219. Epub 2021 Sep 14.

Faculty of Geomatics, Lanzhou Jiaotong University, Lanzhou, 730070, China; Gansu Provincial Engineering Laboratory for National Geographic State Monitoring, Lanzhou, 730070, China. Electronic address:

A dust storm that formed in the north of China and the southeastern part of Mongolia in March 2021 significantly deteriorated air quality over a large area of East Asia. According to the synoptic pattern, the cause of the dust storm was a cyclone with a significant drop in pressure leading to high winds and dry components of the soil over parts of the Gobi Desert becoming airborne. Data obtained from ground-based air quality monitoring stations show that the observed hourly PM concentration greatly exceeded the recommended maximum of 150 μg/m with readings above 1500 μg/m in the cities of Tianjin, Baoding, Zhengzhou, Luoyang, Zhoukou. Read More

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September 2021

Changes in Limbal Optical Coherence Tomography Angiography Outcomes in Patients With Overnight Contact Lens Wear.

Eye Contact Lens 2021 Oct;47(10):552-554

Ophthalmology Department (B.B.C., S.O.), Okan University, Faculty of Medicine, İstanbul, Turkey; Ophthalmology Department (H.B.A.), Okan University, Faculty of Medicine, İstanbul, Turkey; and Ophthalmology Department (E.T.), Okan University, Faculty of Medicine, İstanbul, Turkey.

Objectives: To evaluate the perilimbal vasculature of patients who wear contact lenses (CLs) overnight with optical coherence tomography angiography (OCTA) and compare the results with healthy population.

Methods: Forty-two patients were included in this observational study. The OCTA imaging was performed in the temporal quadrant of the perilimbal region using a swept-source optical coherence tomography system (Triton DRI-OCT; Topcon Corporation, Tokyo, Japan). Read More

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October 2021

Analogs of microgravity: the function of Schlemm's canal, intraocular pressure and autonomic nervous during the head-down tilt test in healthy subjects.

Int J Ophthalmol 2021 18;14(9):1419-1423. Epub 2021 Sep 18.

Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei Province, China.

Aim: To evaluate the ocular outcomes and to elucidate possible mechanisms underlying intraocular pressure (IOP) change following the head-down tilt (HDT) test.

Methods: The study included 21 participants at the Department of Ophthalmology of Tongji Hospital. Subjects received the test of I-care tonometry, enhanced depth imaging optical coherence tomography and heart rate variability (HRV) analysis before and after 15min HDT test. Read More

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September 2021

Clinical Outcomes of Combined Implantation of an Extended Depth of Focus IOL and a Trifocal IOL in a Korean Population.

J Ophthalmol 2021 7;2021:9034258. Epub 2021 Sep 7.

Department of Ophthalmology, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.

Purpose: To evaluate monocular and binocular visual performance and patient-reported outcomes following combined implantation of a diffractive extended depth of focus (EDoF) IOL (Carl Zeiss AT LARA 829MP) and a diffractive trifocal IOL (Carl Zeiss AT LISA tri 839MP).

Methods: This prospective study enrolled consecutive patients undergoing lens phacoemulsification of cataract and combined implantation of an EDoF IOL in the dominant eye and a trifocal IOL in the nondominant eye. Assessment included uncorrected visual acuity at near distances (UNVA), intermediate distances (UIVA), and far distances (UDVA), uncorrected defocus curve, contrast sensitivity (CS), reading speed, and patient satisfaction, evaluated six months after the surgery with the Visual Function Questionnaire (VFQ-25). Read More

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September 2021

Obtaining vertical distribution of PM from CALIOP data and machine learning algorithms.

Sci Total Environ 2021 Sep 15;805:150338. Epub 2021 Sep 15.

College of Atmospheric Science, Lanzhou University, Lanzhou 730000, China.

Aerosol optical depth (AOD) has been widely used to estimate the near-surface PM (fine particulate matter with particle size less than 2.5 μm). However, the total-column AOD obtained by passive remote sensing instruments can neither distinguish the contribution of AOD in various altitude layers nor obtain the vertical PM concentration. Read More

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September 2021

Contrasting seasonal pattern between ground-based PM and MODIS satellite-based aerosol optical depth (AOD) at an urban site in Hanoi, Vietnam.

Environ Sci Pollut Res Int 2021 Sep 16. Epub 2021 Sep 16.

Graduate Institute of Applied Geology, National Central University, Taoyuan, 32000, Taiwan.

This study investigated the seasonal variations of the ground-based PM concentration measured at an urban site and Terra MODIS satellite-based aerosol optical depth (AOD) in Hanoi, Vietnam, during the year 2016. The findings showed the large differences in terms of the seasonal variation of both PM concentration and columnar AOD. Clearly, the ground-based PM concentrations decreased during the summer period and highly increased during the late fall and winter periods. Read More

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September 2021

Estimating PM concentration using the machine learning GA-SVM method to improve the land use regression model in Shaanxi, China.

Ecotoxicol Environ Saf 2021 Sep 13;225:112772. Epub 2021 Sep 13.

School of Environmental and Chemical Engineering, Xi'an Polytechnic University, Xi'an 710048, China.

With rapid economic growth, urbanization and industrialization, fine particulate matter with aerodynamic diameters ≤ 2.5 µm (PM) has become a major pollutant and shows adverse effects on both human health and the atmospheric environment. Many studies on estimating PM concentrations have been performed using statistical regression models and satellite remote sensing. Read More

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September 2021

OCT-A evaluation of radiation vasculopathy following slotted plaque brachytherapy.

Eur J Ophthalmol 2021 Sep 16:11206721211044339. Epub 2021 Sep 16.

The New York Eye Cancer Center, New York, NY, USA.

Purpose: To determine a reliable diagnostic method to reveal and monitor subclinical progression of neural and perineural radiation vasculopathy.

Methods: A retrospective cross-sectional study, where optical coherence tomography angiography (OCT-A) imaging data was collected and analyzed from 22 consecutive patients that had been treated with circumneural slotted plaque brachytherapy for peripapillary, juxtapapillary, or circumpapillary choroidal melanomas. Pre-operative dosimetry of palladium-103 radiation dose to the optic nerve and fovea were collected. Read More

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September 2021

OCT particle tracking velocimetry of biofluids in a microparallel plate strain induction chamber.

J Biomed Opt 2021 Sep;26(9)

The Univ. of North Carolina at Chapel Hill, United States.

Significance: Imaging biofluid flow under physiologic conditions aids in understanding disease processes and health complications. We present a method employing a microparallel plate strain induction chamber (MPPSIC) amenable to optical coherence tomography to track depth-resolved lateral displacement in fluids in real time while under constant and sinusoidal shear.

Aim: Our objective is to track biofluid motion under shearing conditions found in the respiratory epithelium, first validating methods in Newtonian fluids and subsequently assessing the capability of motion-tracking in bronchial mucus. Read More

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September 2021

Coherence function-encoded optical palpation.

Opt Lett 2021 Sep;46(18):4534-4537

Optical palpation maps stress at the surface of biological tissue into 2D images. It relies on measuring surface deformation of a compliant layer, which to date has been performed with optical coherence tomography (OCT). OCT-based optical palpation holds promise for improved clinical diagnostics; however, the complexity and cost hinder broad adoption. Read More

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September 2021

In-depth exploration of mechanism and energy balance characteristics of an advanced continuous microwave pyrolysis coupled with carbon dioxide reforming technology to generate high-quality syngas.

Bioresour Technol 2021 Sep 1;341:125863. Epub 2021 Sep 1.

Micro Optical Instruments (Shenzhen) Inc, Shenzhen 518109, China; Guangdong Engineering Research Center for Intelligent Spectroscopy, China.

This study firstly coupled advanced continuous microwave pyrolysis with CO reforming technology to recover syngas from cow manure and CO. The contribution of CO to syngas, pyrolysis mechanism, and energy balance characteristics were analyzed thoroughly. The results showed that continuous microwave pyrolysis coupled with CO reforming technology has superiorities over other pyrolysis methods in bio-gas generation. Read More

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September 2021

Imaging Sensor for the Detection of the Flow Battery Via Weak Value Amplification.

Anal Chem 2021 Sep 15. Epub 2021 Sep 15.

Institute of Optical Imaging and Sensing, Shenzhen Key Laboratory for Minimal Invasive Medical Technologies, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, People's Republic of China.

Flow battery electrodes are vital for performing redox reactions, and an in-depth understanding of reaction kinetics and spatial distribution differences in electrodes is very important for improving the efficiency of electrochemical reactions. In this study, a reflection-type phase-sensitive weak measurement imaging system was developed for the detection of flow batteries. The phase difference between two polarization components in total internal reflection caused by electrode redox processes was measured by weak value amplification. Read More

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September 2021

Choroidal vascularity index in adults with different refractive status.

Photodiagnosis Photodyn Ther 2021 Sep 11;36:102533. Epub 2021 Sep 11.

Fatih Sultan Mehmet Training and Research Hospital, Atasehir, Istanbul, Turkey.

Aim: We aimed to perform structural analysis of the choroid in adults with different refractive status.

Materials And Methods: A prospective, comparative study of 100 right eyes of 100 patients ages 18-40 years was conducted. The patients were divided into four groups according to spherical equivalent (SE): Group 1: -0. Read More

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September 2021