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Cynthia Wong, Michal E Pawlowski, Alessandra Forcucci, Catherine E Majors, Rebecca Richards-Kortum, Tomasz S Tkaczyk
Fluorescence microscopy can be a powerful tool for cell-based diagnostic assays; however, imaging can be time consuming and labor intensive to perform. Tunable systems give the ability to electronically focus at user selected depths inside an object volume and may simplify the opto-mechanical design of the imaging system. We present a prototype of a universal, tunable, miniature fluorescence microscope built from poly(methyl methacrylate) singlets that incorporates miniature, electrowetted lenses for electronic focusing...
March 1, 2018: Biomedical Optics Express
Mürsel Karadas, Adam M Wojciechowski, Alexander Huck, Nils Ole Dalby, Ulrik Lund Andersen, Axel Thielscher
We suggest a novel approach for wide-field imaging of the neural network dynamics of brain slices that uses highly sensitivity magnetometry based on nitrogen-vacancy (NV) centers in diamond. In-vitro recordings in brain slices is a proven method for the characterization of electrical neural activity and has strongly contributed to our understanding of the mechanisms that govern neural information processing. However, this traditional approach only acquires signals from a few positions, which severely limits its ability to characterize the dynamics of the underlying neural networks...
March 14, 2018: Scientific Reports
Luis M Pazos Outón, T Patrick Xiao, Eli Yablonovitch
Lead halide materials have seen a recent surge of interest from the photovoltaics community following the observation of surprisingly high photovoltaic performance, with opto-electronic properties similar to GaAs. This begs the question; what is the limit for the efficiency of these materials? It has been known that at 1-sun the efficiency limit of crystalline silicon is ~29%, despite the Shockley-Queisser (SQ) limit for its bandgap being ~33%, the discrepancy being due to strong Auger recombination. In this article, we show that Methyl Ammonium Lead Iodide (MAPbI3) likewise has a larger than expected Auger coefficient...
March 14, 2018: Journal of Physical Chemistry Letters
Wentao Huang, Yen-Hung Lin, Thomas D Anthopoulos
Combining high charge carrier mobility with ambipolar transport in light-absorbing organic semiconductors is highly desirable as it leads to enhanced charge photogeneration, and hence improved performance, in various optoelectronic devices including solar cells and photodetectors. Here we report the development of [6,6]-phenyl-C61 -butyric acid methyl ester (PC61 BM)-based ultraviolet (UV) phototransistors with balanced electron and hole transport characteristics. The latter is achieved by fine-tuning the source-drain electrode work function using a self-assembled monolayer...
March 13, 2018: ACS Applied Materials & Interfaces
Bahram Javidi, Adam Markman, Siddharth Rawat
We investigate the use of compact, lensless, single random phase encoding (SRPE) and double random phase encoding (DRPE) systems for automatic cell identification when multiple cells, either of the same or mixed classes, are in the field of view. A microscope glass slide containing the sample is inputted into the single or double random phase encoding system, which is then illuminated by a coherent or partially coherent light source generating a unique opto-biological signature (OBS) that is captured by an image sensor...
March 1, 2018: Applied Optics
Athmane Tadjine, Christophe Delerue
The synthesis of self-assembled semiconductor nanocrystal (NC) superlattices using oriented attachment recently became a flourishing research topic. This technique already produced remarkable forms of NC superlattices, such as linear chains, mono and multilayer square lattices, and silicene-like honeycomb lattices. In the case of lead chalcogenide semiconductors where NCs are in the form of truncated nanocubes, the attachment mostly occurs via (100) facets. In this work, we show that all these structures can be seen as sub-structures of a simple cubic lattice...
March 9, 2018: Physical Chemistry Chemical Physics: PCCP
Ling Liu, Patrick R Onck
Switchable materials in response to external stimuli serve as building blocks to construct microscale functionalized actuators and sensors. Azobenzene-modified liquid crystal (LC) polymeric networks, that combine liquid crystalline orientational order and elasticity, reversibly undergo conformational changes powered by light. We present a computational framework to describe photo-induced topographical transformations of azobenzene-modified LC glassy polymer coatings. A nonlinear light penetration model is combined with an opto-mechanical constitutive relation to simulate various ordered and corrugated topographical textures resulting from aligned or randomly distributed LC molecule orientations...
March 7, 2018: Soft Matter
Maria D Garcia, Camila V Ventura, João R Dias, Ta Chen P Chang, Audina M Berrocal
Purpose: We present the first case in the literature of a patient with Kartagener syndrome and ocular findings of nonexudative age-related macular degeneration. Observations: A 55-year-old woman with Kartagener syndrome and chronic angle closure glaucoma presented for evaluation of the retina. Optos ultra-widefield imaging of the fundus showed glaucomatous cupping, drusen, and retinal pigment epithelium changes within the macular region. Humphrey visual field testing confirmed glaucomatous changes...
June 2018: American Journal of Ophthalmology Case Reports
Edward J Casswell, Sleiman Abou Ltaif, Thomas Carr, Pearse A Keane, David G Charteris, Louisa Wickham
PURPOSE: To describe the widefield spectral-domain optical coherence tomography features of peripheral round retinal holes, with or without associated retinal detachment (RD). METHODS: Retrospective, observational study of 28 eyes with peripheral round retinal holes, with and without RD. Patients underwent imaging with a widefield 50-degree spectral-domain optical coherence tomography (Heidelberg Engineering, Germany) and Optos ultra-widefield imaging systems (Optos, United Kingdom)...
March 2, 2018: Retina
Leonardo Ciocca, Roberto Meneghello, Carlo Monaco, Gianpaolo Savio, Lorenzo Scheda, Maria Rosaria Gatto, Paolo Baldissara
PURPOSE: This study describes a method for measuring the accuracy of the virtual impression. METHODS: In vitro measurements according to a metrological approach were based on (1) use of an opto-mechanical coordinate measuring machine to acquire 3D points from a master model, (2) the mathematical reconstruction of regular geometric features (planes, cylinders, points) from 3D points or an STL file, and (3) consistent definition and evaluation of position and distance errors describing scanning inaccuracies...
March 2, 2018: International Journal of Computer Assisted Radiology and Surgery
Anna V Leopold, Konstantin G Chernov, Vladislav V Verkhusha
Protein kinases are involved in the regulation of many cellular processes including cell differentiation, survival, migration, axon guidance and neuronal plasticity. A growing set of optogenetic tools, termed opto-kinases, allows activation and inhibition of different protein kinases with light. The optogenetic regulation enables fast, reversible and non-invasive manipulation of protein kinase activities, complementing traditional methods, such as treatment with growth factors, protein kinase inhibitors or chemical dimerizers...
March 2, 2018: Chemical Society Reviews
Geonyeop Lee, Stephen J Pearton, Fan Ren, Jihyun Kim
Layered heterojunctions are widely applied as fundamental building blocks for semiconductor devices. For the construction of nanoelectronic and nanophotonic devices, the implementation of two-dimensional materials (2DMs) is essential. However, studies of junction devices composed of 2DMs are still largely focused on single p-n junction devices. In this study, we demonstrate a novel pnp double heterojunction fabricated by the vertical stacking of 2DMs (black phosphorus (BP) and MoS2 ) using dry-transfer techniques, and the formation of high quality p-n heterojunctions between the BP and MoS2 in the vertically stacked BP/MoS2/BP structure...
February 27, 2018: ACS Applied Materials & Interfaces
M Petruzzella, Ž Zobenica, M Cotrufo, V Zardetto, A Mameli, F Pagliano, S Koelling, F W M van Otten, F Roozeboom, W M M Kessels, R W van der Heijden, A Fiore
A method to avoid the stiction failure in nano-electro-opto-mechanical systems has been demonstrated by coating the system with an anti-stiction layer of Al2 O3 grown by atomic layer deposition techniques. The device based on a double-membrane photonic crystal cavity can be reversibly operated from the pull-in back to its release status. This enables to electrically switch the wavelength of a mode over ~50 nm with a potential modulation frequency above 2 MHz. These results pave the way to reliable nano-mechanical sensors and optical switches...
February 19, 2018: Optics Express
Giulia Rigamonti, Valentina Bello, Sabina Merlo
For answering the growing demand of innovative micro-fluidic devices able to measure the refractive index of samples in extremely low volumes, this paper presents an overview of the performances of a micro-opto-fluidic sensing platform that employs rectangular, miniature hollow glass tubings. The operating principle is described by showing the analytical model of the tubing, obtained as superposition of different optical cavities, and the optical readout method based on spectral reflectivity detection. We have analyzed, in particular, the theoretical and experimental optical features of rectangular tubings with asymmetrical geometry, thus with channel depth larger than the thickness of the glass walls, though all of them in the range of a few tens of micrometers...
February 16, 2018: Sensors
Hai Zhang, Kuan Li, Hong-Sheng Chen, Shuang-Qi Gao, Zhi-Xuan Xia, Jie-Ting Zhang, Fang Wang, Jian-Guo Chen
Hypofunction of the serotonergic (5-HT) system has close relationship with the symptoms in major depressive disorders (MDD), however, the underlying neural circuitry mechanisms are not fully understood. Lateral habenula (LHb) plays a crucial role in aversive behaviors and is activated in conditions of depression. It has been reported that 5-HT inhibits the excitability of LHb neurons, leading to the hypothesis that decreased transmission of 5-HT would elevate the activity of LHb and therefore mediates depressive symptoms...
February 19, 2018: Brain Structure & Function
Josien C van den Noort, Henk G Kortier, Nathalie van Beek, DirkJan H E J Veeger, Peter H Veltink
[This corrects the article DOI: 10.1371/journal.pone.0164889.].
2018: PloS One
Yixiong Ji, Jun Yang, Wei Luo, Linlong Tang, Xiangxing Bai, Chongqian Leng, Chaoyan Ma, Xingzhan Wei, Jing Wang, Jun Shen, Shirong Lu, Kuan Sun, Haofei Shi
Driven by huge demand for flexible opto-electronic devices, high-performance flexible transparent electrodes are continuously sought. In this work, a flexible multilayer transparent electrode with structure of ZnO/Ag/CuSCN (ZAC) is engineered, featuring inorganic solution-processed cuprous thiocyanate (CuSCN) as a hole-transport antireflection coating. The ZAC electrode exhibits an average transmittance of 94% (discounting the substrate) in the visible range, a sheet resistance (Rsh) of 9.7 Ω/sq, a high mechanical flexibility without Rsh variation after bending 10,000 times, a long-term stability of 400 days in ambient environment and scalable fabrication process...
February 16, 2018: ACS Applied Materials & Interfaces
Intu Sharma, Yogita Batra, V Flauraud, Jürgen Brugger, Bodh Raj Mehta
The growth of MoS2 layers of desired dimensions at predefined locations is essential for fabricating opto-electronic devices based solely on MoS2 or on hetero-structures based on MoS2. Here we present a new route for patterned growth of MoS2 by combining radio frequency (RF) magnetron sputtering, stencil mask lithography and vapour phase sulfurization. The present method does not involve chemical etchants and organic photoresist and hence provides a simplified process of achieving MoS2 patterns. Here, the control over the number of layers (mono, few and bulk) of MoS2 is achieved by varying the thickness of Mo films...
March 1, 2018: Journal of Nanoscience and Nanotechnology
Hongmiao Tian, Zhijian Wang, Yilong Chen, Jinyou Shao, Tong Gao, Shengqiang Cai
Optically-driven active materials have received much attention because their deformation and motion can be controlled remotely, instantly and precisely in a contactless way. In this article, we investigated an optically-actuated elastomer with rapid response: polydopamine (PDA)-coated liquid crystal elastomer (LCE). Due to the photothermal effect of PDA coating and thermal responsiveness of LCE, the elastomer film contracted significantly with near infrared (NIR) irradiation. With a fixed strain, light-induced actuating stress in the film could be as large as 1...
February 15, 2018: ACS Applied Materials & Interfaces
Wenying Fan, Akihito Uji, Enrico Borrelli, Michael Singer, Min Sagong, Jano van Hemert, Srinivas R Sadda
PURPOSE: To characterize and quantify the total retinal vascular bed area (RVBA) and vascular density (VD) in normal eyes using stereographically-corrected ultra-wide (UWF) fluorescein angiography (FA). DESIGN: Cross-sectional study METHODS: Fifty-nine eyes of 31 normal subjects with no evidence of ocular disease underwent FA using the Optos 200Tx. Central and peripheral-steered FA images were montaged and stereographically projected. The early phase FA was used to extract the retinal vasculature as a binary mask...
February 8, 2018: American Journal of Ophthalmology
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