Mirror Microscope Research Articles

Analysis of influencing factors of corneal edema after phacoemulsification for diabetic cataract.

The paper aimed to explore the influence factors of corneal edema after phacoemulsification for diabetic cataracts. For this aim, 80 patients (80 eyes) with senile cataracts who underwent phacoemulsification implantation in our hospital from August 2021 to January 2022 were included in this study, including 39 males (48.75%) and 41 females (51.25%), with an average age of 70.35±5.22 years. The OCT system during ophthalmology was used to capture corneal OCT images in the center of the cornea in real time before the phacoemulsification (the phacoemulsification probe just entered the anterior chamber after the balanced saline left the separated nucleus), at the end of phacoemulsification (when the phacoemulsification ultrasound probe was still in the anterior chamber and the perfusion pressure did not change compared with that in the previous step), at the end of perfusion aspiration (after the perfusion aspiration probe left the anterior chamber), and after surgery (after the watertight incision is closed). The corneal thickness was measured at each time point using Photoshop software. AL, curvature and ACD were measured using IOL-Master bio-measurement technology, and ACD referred to the distance between the front surface of the cornea and the front surface of the lens. Endothelial cell density was measured using CIM-530 non-contact mirror microscope. A handheld rebound tonometer was used to measure intraocular pressure and optical coherence tomography was used to assess the macular area of the fundus. Fundus photography was performed with a non-diffuse fundus camera. The results indicated that the preoperative corneal thickness was 514.35±29.62 μm, and the average corneal thickness at the end of the operation was 535.26±30.29μm, which was increased by 20.91±1.67 μm compared with that before operation (P<0.05), and the increase rate of corneal thickness was 4.07%. The corneal thickness of patients tended to increase with the increase in operation time and intraocular operation time (P<0.05). The distribution of corneal edema-related features showed that 42.50% of patients had persistent edema at the time of cataract surgery. The median onset time of corneal edema in the remaining patients was 5.44 years (1.96-21.35 years for 90% CR). The higher the nuclear hardness, the more severe the cataract, and the higher APT, EPT, APE, and TST (P<0.05). The older the patient, the higher the grade of cataract nucleus, and the higher EPT, APE, and TST, the greater the intraoperative corneal thickening (P<0.05). The higher the maximum area of endothelial cells, the greater the intraoperative corneal thickness increase, the lower the corneal endothelial cell density and the greater the intraoperative corneal thickness increase (P<0.05). It was concluded that postoperative corneal edema in phacoemulsification surgery for diabetic cataracts is closely related to intraocular perfusion pressure, nuclear hardness of lens, the density of corneal endothelial cells, the energy of phacoemulsification and duration.

Learning and evaluating the overlapping roles of physics and physiology in perceiving contrast and resolution in microscopy

AbstractSimple compound microscopy is widely used across the globe. However, contrast and resolution fascinate students and are difficult to learn due to their limited practical experience. Although the laws of physics have been derived thoroughly, their real implementation in the human body is uncertain. This study quantifies contrast and resolution through human perception and technological tools and assesses the degree of overlap between physics and physiology. Thus, an opaque repository for a compound microscope with a mobile holder is devised to capture the images of Leishman-stained smears and USAF targets. Another receptacle is fabricated to hold coloured filters against a light bulb, which projects on the microscope mirror through a connecting pipe. The images with a different sequence of filters are subjected to analysis by volunteers and using digital image processing techniques. The perception of contrast and resolution through the human eye and digital processing shows an overlap of 82.57% for contrast and 76.40% for resolution. Also, participants opt for contrast (81.66%) against the resolution (75.51%). The preferred sequence of light for contrast and resolution is white &gt; green &gt; blue &gt; red and white &gt; blue &gt; green &gt; red, respectively. Green &gt; blue &gt; red is preceded by white when both contrast and resolution are examined concurrently. Thus, the integrated role of the two disciplines in learning contrast and resolution has been studied and evaluated practically beyond the limits of the textbook on a hands-on basis. Simultaneously, the subjective selection of resolution or contrast using low-cost colour filters is an affordable approach to upgrade a microscope. Graphical abstract

A clinical case of linear stromal (interstitial) keratitis

Background. Keratitis, characterized by superficial inflammation, cellular infiltration and vascularization of the stroma with minimal involvement of the corneal epithelium and endothelium, is an extremely rare specific condition, that has been isolated, as a separate nosology – linear interstitial keratitis.The aim. Clinical case demonstration of linear stromal keratitis, using modern methods of corneal examination and world literature analysis, devoted to this problem, from the point of view of determining disease etiology.Materials and methods. Case demonstration of linear keratitis in a young patient with a recurrent course of the disease is presented.Results. Рresented clinical case confirms course features and lesion morphology of linear interstitial keratitis.Conclusion. Linear interstitial keratitis is a rare clinical phenomenon, and its etiology remains uncertain. Confocal microscopy is a promising method of studying linear interstitial keratitis in view of best resolution. Coherent tomography of anterior segment of the eye, is uninformative and does not reflect true depth of the pathological process. Mirror microscopy of endothelial cells confirms confocal microscopy data of panstromic process. Herpes simplex virus and pale treponema roles in the development of linear interstitial keratitis has not been confirmed by existing standard laboratory methods.

Monolithic piezoceramic actuators with a twist

Designing artificial structures with heterogeneous elements and manipulating their interface coupling ways usually bring in synthetic neo-nature to functional devices. For piezoceramic devices, the deformation response refers to a variety of extensional, contractional, or shear modes of crystals, and also relies on boundary conditions from morphology design. However, to pursue fundamental torsion actuation in an integrated piezoceramic component is still a long-term tough task due to nil twist mode limited by microscopic crystal mirror symmetry. Herein, we demonstrate a design of cofired monolithic actuators to originally overcome this obstacle. The prototype device is composed of two sets of stacked actuation subunits that work on artificially reverse face shear modes, and their chiral stiffness couplings will synergistically contribute to synthetic twist outputs at a broad bandwidth. Finite element simulation reveals twist displacements are highly tunable by manipulating the geometrical dimensions. Transverse deflection measurements manifest the stable and sizeable linear actuation response to applied electric fields (around 3.7 µm under 40 V at 1 Hz). Importantly, the design actually introduces a more general route to enable arbitrary modes and actuation states in integrated piezoceramic components.

Solid-solid dewetting of scandium thin films on the W(100) surface observed using emission microscopy

Several operating modes of cathode lens emission microscopy are used to observe scandium on W(100), including mirror microscopy, thermionic emission microscopy, and low energy electron diffraction. Scandium thin films are deposited by thermal evaporation from a metal source onto W(100). The scandium films on W(100) are observed to dewet from the W(100) surface and to form droplets when the surface is heated: the dewetting temperature is thickness dependent and spans a range from 500 to 900 °C, which is far below the melting temperature (1541 °C). Thinner films produce smaller droplets; a range of film thicknesses from 5 to 30 nm was tested. X-ray photoelectron spectroscopy of the scandium films exposed to oxygen was also measured in order to understand the function of scandium in thermionic cathodes. The shift of the W 4f peaks upon oxygen absorption, scandium adsorption, and subsequent heating indicates that oxygen preferentially bonds to scandium. The shift in the scandium 3p level indicates formation of Sc2O3.

Light collection from a low-temperature scanning tunneling microscope using integrated mirror tips fabricated by direct laser writing.

We report on a cryogenic scanning tunneling microscope (STM) designed for single molecule studies, in which the light emitted from the tunneling junction is collected by an integrated optics on the tip. Using direct laser writing, the tip and the surrounding microscopic parabolic mirror are fabricated as one piece, which is small enough to collimate the collected light directly into an optical multimode fiber fixed inside the STM. This simple and compact setup combines high collection efficiency and ease of handling while not interfering with the cryostat operation, allowing uninterrupted measurements at 1.4 K for up to 5 days with low drift.

An evaluation of the scanning electron microscope mirror effect to study viscoelastically prestressed polymeric matrix composites

A viscoelastically prestressed polymeric matrix composite (VPPMC) is produced by applying tensile creep to polymeric fibres, the creep load being removed before the fibres are moulded into a resin matrix. Following matrix curing, the viscoelastically strained fibres impart compressive stresses to the surrounding matrix, counterbalanced by residual tension in the fibres. VPPMCs based on nylon 6,6 fibres in polyester resin have previously demonstrated improvements in mechanical properties of up to 50% compared with control (unstressed) counterparts. Although the associated viscoelastic recovery forces are understood, little is known of the fibre-matrix interactions relating to prestress within VPPMCs. This is addressed by investigating composite samples with the scanning electron microscope mirror effect (SEMME). By comparing results from VPPMC samples with their control counterparts, the findings suggest that there are ∼30% fewer trapped negative charges in the former, implying that the VPPMCs possess higher fibre-matrix interfacial strengths. Tensile test results on similar composite samples support these findings. The effects of resin porosity in SEMME data are also evaluated and our findings suggest that porosity can significantly increase charge trapping.

CMOS Compatible Fabrication Processes for the Digital Micromirror Device

DLP® technology has been widely used in the display products since it was first introduced to the world in 1996 by Texas Instruments. Projectors powered by DLP® technology range from cinema projectors that light up large movie theater screens to palm-sized “Pico” projectors. The heart of the technology is the digital micromirror device (DMD) that features an addressable array of up to 8 million microscopic mirrors. DMDs are fabricated using standard semiconductor processing equipment. However due to the unique nature of MOEMS application and digital operation of the DMDs, special CMOS-compatible fabrication processes have been developed to produce highly reflective digital micromirrors with robust operation margin and long term reliability. This paper will present an overview of the fabrication processes of the DMDs.

Hornhautendothelzelldichte in Abhängigkeit vom Schweregrad der Pseudoexfoliation

Pseudoexfoliation (PEX) syndrome is a common, age-related disease which is associated with the multifocal deposition of fibrillar PEX material in intra- and extraocular tissues. Subsequently among others second chronic open-angle glaucoma and corneal endothelial cell loss occurs. The present study analysed whether there is a correlation between the stage of the PEX process and corneal endothelial cell density (cECD), regardless of the non-existence or proof of secondary glaucoma. One eye of 109 Caucasian subjects (mean age 71.7 years) was examined by slit-lamp microscopy and classified based on visible PEX deposits on the lens (mild and severe) and presence of glaucoma in 4 study groups. The control groups were healthy subjects and patients with primary open angle glaucoma (POAG). The cECD was measured with the endothelial cell mirror microscope (SeaEagle). All study groups and the POAG group showed a significant cECD reduction compared to the healthy control group: POAG: 6.0 %; PEX syndrome: mild 5.5 % and severe 11.0 %, PEX glaucoma: mild 7.7 % and severe 12.3 %. Further the cECD was significantly lower compared to the POAG group in severe PEX syndrome by 5.4 % and in severe PEX glaucoma by 6.8 %. cECD significantly decreased with increasing PEX stage independently of the presence of glaucoma. These differences remained statistically significant after Bonferroni-Holm correction. The analysis of the entire group of test subjects showed only a weak correlation between mean intraocular pressure and mean cECD. The results of this study showed a decreasing cECD with increasing PEX stage, regardless of whether glaucoma is present or not. The influence of the PEX process appears to be more pronounced than the influence of intraocular pressure.

Study of dynamic behavior of trapped charge in the insulating materials by using a new experimental approach

Abstract A new experimental procedure is proposed which uses the Scanning Electron Microscope Mirror Effect (SEMME) for the dynamic investigation of charge trapping in insulating materials. This experimental procedure allows to the mirror method which is usually described as static to be considered as dynamic. The dynamic trapping properties of the polymethyl-methacrylate (PMMA) polymer material are investigated and the time constants of charge processes are evaluated for various accelerating voltages. The experimental results reveal that the values of trapped charge at steady state obtained by the proposed procedure are in good agreement with these obtained using the electrostatic influence method (EIM) under the identical experimental conditions of electron irradiation.

Compact Kirkpatrick–Baez microscope mirrors for imaging laser-plasma x-ray emission

Compact Kirkpatrick-Baez microscope mirror components for use in imaging laser-plasma x-ray emission have been manufactured, coated, and tested. A single mirror pair has dimensions of 14 × 7 × 9 mm and a best resolution of ~5 μm. The mirrors are coated with Ir providing a useful energy range of 2-8 keV when operated at a grazing angle of 0.7°. The mirrors can be circularly arranged to provide 16 images of the target emission a configuration best suited for use in combination with a custom framing camera [F. J. Marshall, J. A. Oertel, and P. J. Walsh, Rev. Sci. Instrum. 75, 4045 (2004)]. An alternative arrangement of the mirrors would allow alignment of the images with a four-strip framing camera such as described in D. K. Bradley et al. [Rev. Sci. Instrum. 66, 716 (1995)].

Modeling electric charge distribution on insulator under electron bombardment: Case of rectangular surface implantation

Despite progress in the study of dielectric properties and the formation of secondary electrons images and especially in the understanding of their mirror curve shape, since the first models for mirror equation were developed, an exact quantitative prediction of the mirror curve for most materials has remained an unsolved problem. In this paper, recent development in the characterization of charge trapping ability of insulators using the scanning electron microscope mirror method (SEMMM) is reviewed. All this work has resulted in unprecedented insights into the early stage of dielectric study and it is also relevant for a deeper understanding of this anomalous effect (mirror effect) as well as for discussion of the factors affecting it. So the dependency of elliptic mirror and the anisotropic effect in the trapping phenomena of charge is highlighted.

Electric charge trapping, residual stresses and properties of ceramics after metal/ceramics bonding

Abstract The use of ceramic components in electrical engineering and mechanical applications is rapidly increasing. Most of these applications require the use of ceramics bonded with metal. In this paper, we have studied the role of residual stresses occurring after joining between an industrial alumina ceramic (Al 2 O 3 ) and Ni-based super-alloy, on the dielectric behaviour of ceramics. The electric charging phenomenon i.e. trapping–detrapping or diffusion of electric charges is studied by Scanning Electron Microscope Mirror Effect (SEMME) coupled with the Induced Current Method (ICM). Knowing that localized trapped charges in ceramics is a source of damage, the correlation between residual stress intensity, apparent-toughness of ceramics and ability to trap charges near the interface was demonstrated: the SEMME and ICM measurements of the quantities of trapped charges near the interface, highlighted the changes in the ceramic properties related to residual stresses due to both thermo-mechanical effect and diffusion of metallic species in the ceramics, during the bonding process.

Spatially Complex Diffraction-Limited Photolysis of Caged Calcium and IP3 Combined with High-Speed Confocal Imaging

The novel Mosaic digital illumination system (Photonic Instruments/Andor Group) integrated into a Nikon A1R confocal microscope was used to uncage Ca (DM-nitrophen, NP-EGTA) or IP3 from multiple geometrically complex (Fig.) diffraction-limited subcellular regions and simultaneously measure [Ca]i with high-speed 2-dimensional confocal imaging (430 fps). The Mosaic System uses a computer controlled spatial light modulator to map a diffraction limited mask onto the specimen plane. A Digital Micromirror Device, consisting of a high speed array of hinge-mounted individually addressable, tiltable microscopic mirrors, directs continuous wave laser light (405 nm) onto the image plane according the user-defined diffraction limited mask. Local uncaging of Ca from multiple small regions of interest (0.63 micrometer diameter) generated artificial Ca sparks outside the cell and produced CICR inside permeabilized cardiac myocytes. Uncaging Ca from a 0.63x10 micrometer region triggered CICR and propagating Ca waves. Subsarcolemmal uncaging of IP3 initiated propagating Ca waves that originated within the region of uncaging, and caused increased peak amplitude of electrically evoked Ca transients and Ca alternans, suggesting that in cardiac myocytes Ca release from IP3 recpetors primes ryanodine receptor Ca release channels and enhances CICR.

Mechanical and dielectric characterization of hemp fibre reinforced polypropylene (HFRPP) by dry impregnation process

Natural fibres such as jute, coir, sisal, bamboo and pineapple are known to have high specific strength and can be effectively used in composites in various applications. The use of hemp fibres to reinforce the polymer aroused great inter- est and expectations amongst scientists and materials engineers. In this paper, composites with isotactic polypropylene (iPP) matrix and hemp fibres were studied. These materials were manufactured via the patented FIBROLINE process based on the principle of the dry impregnation of a fibre assembly with a thermoplastic powder (iPP), using an alternating electric field. The aim of this paper is to show the influence of fibre/matrix interfaces on dielectric properties coupled with mechan- ical behaviours. Fibres or more probably the fibre/matrix interfaces allow the diffusion of electric charges and delocalise the polarisation energy. In this way, damages are limited during mechanical loading and the mechanical properties of the composites increase. The structure of composite samples was investigated by X-ray and FTIR analysis. The mechanical properties were analysed by quasistatic and dynamic tests. The dielectric investigations were carried out using the SEMME (Scanning Electron Microscope Mirror Effect) method coupled with the measurement of the induced current (ICM).

Temperature effect on dielectric behavior of an industrial porcelain-type ceramic

For a better understanding of the physical mechanisms involved in insulators submitted to electron irradiation inside a scanning electron microscope, it is important to investigate charge trapping and detrapping. The commonly used technique to deduce the trapping ability and the motion process of electric charges is based on two complementary experimental methods: the scanning electron microscope mirror effect (SEMME) and the induced current measurement (ICM). In this paper, our study is devoted to the influence of temperature on the behavior of porcelain materials during electron injection time. To evaluate the geometry of the trapped charge distribution, a detailed analysis using the mirror image formation and its evolution is developed.

Chromatic-free spatially resolved optical emission spectroscopy diagnostics for microplasma

A chromatic-free spatially resolved diagnostic system for microplasma measurement is proposed and demonstrated, which consists of an optical chromatic-free microscope mirror system, an electron multiplying charge coupled device (EMCCD), and bandpass filters. The diagnostic system free of chromatic aberrations with a spatial resolution of about 6 microm is achieved. The factors that limit the resolution of this diagnostic system have been analyzed, which are optical diffraction, the pixel size of the EMCCD, and the thickness of the microplasma. In this paper, the optimal condition for achieving a maximum resolution power has been analyzed. With this diagnostic system, we revealed the spatial nonuniformity of a microwave atmospheric-pressure argon microplasma. Furthermore, the spatial distribution of the time-averaged effective electron temperature has been estimated from the intensity distributions of 750.4 and 415.8 nm emissions.

Mirrored pyramidal wells for simultaneous multiple vantage point microscopy.

We report a novel method for obtaining simultaneous images from multiple vantage points of a microscopic specimen using size-matched microscopic mirrors created from anisotropically etched silicon. The resulting pyramidal wells enable bright-field and fluorescent side-view images, and when combined with z-sectioning, provide additional information for 3D reconstructions of the specimen. We have demonstrated the 3D localization and tracking over time of the centrosome of a live Dictyostelium discoideum. The simultaneous acquisition of images from multiple perspectives also provides a five-fold increase in the theoretical collection efficiency of emitted photons, a property which may be useful for low-light imaging modalities such as bioluminescence, or low abundance surface-marker labelling.

Time-Lapse Observation of Electrolysis of Copper Sulfate with a Full-Field X-ray Fluorescence Imaging Microscope

The time-lapse observation of the electrodeposition of copper in copper sulfate solution was performed by imaging X-ray fluorescence from the copper deposition. The X-ray fluorescence was directly imaged with a full-field Wolter mirror microscope, which was constructed at the Photon Factory. Controlling the electric current in the solution from 0 to 71.7 µA, the deposition of copper on a Pt cathode was directly observed by imaging its X-ray fluorescence. One exposure time for obtaining an X-ray fluorescence image was 80 s. Then, it was 17 min later from the beginning of the electrolysis when the X-ray fluorescence image of the electrodeposition is observed for the first time. At this exposure time, the detection limit of the mass of copper was estimated to be 0.60 pg/image, which was calculated using test samples of 1.00×10-3–1.00 mol/l copper sulfate solutions.

Dielectric and friction behaviour of unidirectional glass fibre reinforced epoxy (GFRE)

The aim of this paper is to confirm the role of the electric charges on the friction behaviour of non-conductive materials. This correlation is proven using tribo-tests and SEMME (Scanning Electron Microscope Mirror Effect) measurements carried out on the neat epoxy matrix and on two GFRE composites, which only differ by the sizing of the fibres. For the matrix, the influence of friction is only obvious inside the friction track but, for the composites, a modification of the properties of the whole composite (inside and outside the friction track) is observed after friction. Consequently, the glass fibre/matrix interfaces play the role of diffusion path and, then, allow the trapping of electric charges, inducing the formation of defects, as proved by the dielectric modification of material, outside the friction track. In addition, it will be noted that a diffusion of electric charges through the fibre–matrix interfaces permits a stabilization of the friction coefficient and a limitation of the wear, whereas a localised trapping of charges on the interfaces is a source of damage and wear. In this way, the choice of the sizing process permits to control the motion of the electric charges and, consequently, to optimize the mechanical and tribological properties of the composites.