Reflected light imaging of ON and OFF responses in frog retina

2009 ◽  
Author(s):  
Xin-Cheng Yao ◽  
Lei Liu ◽  
Yang-Guo Li
Keyword(s):  
Reflected Light ◽  
Frog Retina

Morphological and elemental analysis of isolated incubated frog retina-choroid

1984 ◽  
Vol 42 ◽  
pp. 298-299
Author(s):  
B. J. Panessa-Warren ◽  
J. B. Warren ◽  
H. W. Kraner
Keyword(s):  
Elemental Analysis ◽  
Pigment Epithelium ◽  
Human Retina ◽  
Healthy Individuals ◽  
Anterior Portion ◽  
Pathological Conditions ◽  
Frog Retina ◽  
Isolated Retina ◽  
Vertebrate Eye ◽  
Retina Pigment Epithelium

Our previous studies have demonstrated that abnormally high amounts of calcium (Ca) and zinc (Zn) can be accumulated in human retina-choroid under pathological conditions and that barium (Ba), which was not detected in the eyes of healthy individuals, is deposited in the retina pigment epithelium (RPE), and to a lesser extent in the sensory retina and iris. In an attempt to understand how these cations can be accumulated in the vertebrate eye, a morphological and microanalytical study of the uptake and loss of specific cations (K, Ca,Ba,Zn) was undertaken with incubated Rana catesbiana isolated retina and RPE preparations. Large frogs (650-800 gms) were dark adapted, guillotined and their eyes enucleated in deep ruby light. The eyes were hemisected behind the ora serrata and the anterior portion of the eye removed. The eyecup was bisected along the plane of the optic disc and the two segments of retina peeled away from the RPE and incubated.

Confocal laser microscopy of impregnated central nervous system tissue

1988 ◽  
Vol 46 ◽  
pp. 94-95
Author(s):  
J.N. Turner ◽  
M. Siemens ◽  
D. Szarowski ◽  
D.N. Collins
Keyword(s):  
Electron Microscopy ◽  
Central Nervous System ◽  
Nervous System ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Confocal Laser ◽  
High Contrast ◽  
Central Nervous System Tissue ◽  
Tissue Samples ◽  
Reflected Light

A classic preparation of central nervous system tissue (CNS) is the Golgi procedure popularized by Cajal. The method is partially specific as only a few cells are impregnated with silver chromate usualy after osmium post fixation. Samples are observable by light (LM) or electron microscopy (EM). However, the impregnation is often so dense that structures are masked in EM, and the osmium background may be undesirable in LM. Gold toning is used for a subtle but high contrast EM preparation, and osmium can be omitted for LM. We are investigating these preparations as part of a study to develop correlative LM and EM (particularly HVEM) methodologies in neurobiology. Confocal light microscopy is particularly useful as the impregnated cells have extensive three-dimensional structure in tissue samples from one to several hundred micrometers thick. Boyde has observed similar preparations in the tandem scanning reflected light microscope (TSRLM).

Some early history of replica techniques for electron microscopy

1992 ◽  
Vol 50 (2) ◽  
pp. 1076-1077
Author(s):  
Robert M. Fisher
Keyword(s):  
Thin Film ◽  
Electron Microscopy ◽  
Optical Microscope ◽  
Early History ◽  
Bulk Materials ◽  
Thin Sections ◽  
Transmission Electron ◽  
Reflected Light ◽  
History Of ◽  
Electron Microscopes

By 1940, a half dozen or so commercial or home-built transmission electron microscopes were in use for studies of the ultrastructure of matter. These operated at 30-60 kV and most pioneering microscopists were preoccupied with their search for electron transparent substrates to support dispersions of particulates or bacteria for TEM examination and did not contemplate studies of bulk materials. Metallurgist H. Mahl and other physical scientists, accustomed to examining etched, deformed or machined specimens by reflected light in the optical microscope, were also highly motivated to capitalize on the superior resolution of the electron microscope. Mahl originated several methods of preparing thin oxide or lacquer impressions of surfaces that were transparent in his 50 kV TEM. The utility of replication was recognized immediately and many variations on the theme, including two-step negative-positive replicas, soon appeared. Intense development of replica techniques slowed after 1955 but important advances still occur. The availability of 100 kV instruments, advent of thin film methods for metals and ceramics and microtoming of thin sections for biological specimens largely eliminated any need to resort to replicas.

Tandem scanning reflected light microscopy: How it works and applications

1986 ◽  
Vol 44 ◽  
pp. 84-87
Author(s):  
Alan Boyde ◽  
Milan Hadravský ◽  
Mojmír Petran ◽  
Timothy F. Watson ◽  
Sheila J. Jones ◽  
...  
Keyword(s):  
Light Microscopy ◽  
Focal Plane ◽  
Central Symmetry ◽  
Single Line ◽  
Scanning Microscope ◽  
Reflected Light ◽  
Illuminating Light ◽  
Illuminating Beam

The principles of tandem scanning reflected light microscopy and the design of recent instruments are fully described elsewhere and here only briefly. The illuminating light is intercepted by a rotating aperture disc which lies in the intermediate focal plane of a standard LM objective. This device provides an array of separate scanning beams which light up corresponding patches in the plane of focus more intensely than out of focus layers. Reflected light from these patches is imaged on to a matching array of apertures on the opposite side of the same aperture disc and which are scanning in the focal plane of the eyepiece. An arrangement of mirrors converts the central symmetry of the disc into congruency, so that the array of apertures which chop the illuminating beam is identical with the array on the observation side. Thus both illumination and “detection” are scanned in tandem, giving rise to the name Tandem Scanning Microscope (TSM). The apertures are arranged on Archimedean spirals: each opposed pair scans a single line in the image.

Modelling Light Transmission in a Fiber-Optical Reflection System

2004 ◽  
Vol 9 (1) ◽  
pp. 55-63
Author(s):  
V. Kleiza
Keyword(s):  
Optical Sensors ◽  
Light Transmission ◽  
External Cavity ◽  
Linear Displacement ◽  
Fiber System ◽  
Light Emitting ◽  
Optical Media ◽  
Reflected Light ◽  
Fiber Optical ◽  
Fiber Optical Sensors

Light transmission in the reflection fiber system, located in external optical media, has been investigated for application as sensors. The system was simulated by different models, including external cavity parameters such as the distance between light emitting and receiving fibers and mirror positioning distance. The sensitivity to a linear displacement of the sensors was studied as a function of the distance between the tips of the light emitting fiber and the center of the pair reflected light collecting fibers, by positioning a mirror. Physical fundamentals and operating principles of the advanced fiber optical sensors were revealed.

Plastic Mulch Color Effects on Light Micro-environment and Watermelon Plant Growth

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 474d-474
Author(s):  
N.K. Damayanthi Ranwala ◽  
Dennis R. Decoteau
Keyword(s):  
Plant Growth ◽  
Light Transmission ◽  
Root Zone ◽  
Dry Mass ◽  
Plant Responses ◽  
Plastic Mulch ◽  
Plant Parts ◽  
Reflected Light ◽  
Total Light ◽  
Dry Mass Partitioning

This study was conducted to evaluate the spectral properties of various colored plastic color mulches and to determine the effects of upwardly reflected light from the mulch surfaces on watermelon plant growth when differences in root zone temperatures are minimized. Two-week-old watermelon plants were grown with black mulch, red-painted mulch, SRM-Red mulch (Sonoco, Inc., Harstville, S.C.), and white mulch. Total light reflection (58 μmol·m–2·s–1 in 400–700 nm) and red: far-red (R:FR = 0.44) of reflected light were lower in black mulch and highest in white mulch (634 and 0.92, respectively). Both black mulch and white mulch had same blue:red (B:R = 0.6) while white mulch had higher B:FR (0.58) in reflected light compared to black mulch (0.26). Reflective properties of red mulches were somewhat similar, and R:FR, B:R, and B:FR were 0.8, 0.2, and 0.18, respectively. However, SRM-Red mulch had highest total light (355 μmol·m–2·s–1 in 400–700 nm) transmission through the mulch, and R:FR, B:R, and B:FR were 0.84, 0.28, and 0.23, respectively. Light transmission through the other mulches was nonsignificant. Watermelon plants grown with black mulch and red mulches had higher internode lengths compared to white mulch after 20 days. Further, plants grown under black had significant higher petiole elongation accompanied with higher dry mass partitioning to petioles, and lower partitioning to roots, stems, and leaves. There was no effects of surface mulch color on total plant dry mass or photosynthesis although plants with black had higher transpiration rate. This suggests the differential regulation of dry mass partitioning among plant parts due to mulch color. The similar plant responses with black mulch and white mulch to plants treated with FR or R light at the end of photoperiod implies the involvement of phytochrome regulation of growth due to mulch surface color.

Electrically-Controllable Liquid Crystal Polarizing Filter for Eliminating Reflected Light

1998 ◽  
Vol 5 (2) ◽  
pp. 93-98 ◽  
Author(s):  
Hideo Fujikake ◽  
Kuniharu Takizawa ◽  
Tahito Aida ◽  
Hiroshi Kikuchi ◽  
Takanori Fujii ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Reflected Light

scholarly journals Tamuraite, Ir5Fe10S16, a New Species of Platinum-Group Mineral from the Sisim Placer Zone, Eastern Sayans, Russia

Minerals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 545
Author(s):  
Andrei Y. Barkov ◽  
Nadezhda D. Tolstykh ◽  
Robert F. Martin ◽  
Andrew M. McDonald
Keyword(s):  
National Laboratory ◽  
X Ray Diffraction ◽  
Calculated Density ◽  
Cell Parameters ◽  
Reflected Light ◽  
Platinum Group Minerals ◽  
Platinum Group ◽  
Probable Space ◽  
Layered Complex ◽  
Residual Melt

Tamuraite, ideally Ir5Fe10S16, occurs as discrete phases (≤20 μm) in composite inclusions hosted by grains of osmium (≤0.5 mm across) rich in Ir, in association with other platinum-group minerals in the River Ko deposit of the Sisim Placer Zone, southern Krasnoyarskiy Kray, Russia. In droplet-like inclusions, tamuraite is typically intergrown with Rh-rich pentlandite and Ir-bearing members of the laurite–erlichmanite series (up to ~20 mol.% “IrS2”). Tamuraite is gray to brownish gray in reflected light. It is opaque, with a metallic luster. Its bireflectance is very weak to absent. It is nonpleochroic to slightly pleochroic (grayish to light brown tints). It appears to be very weakly anisotropic. The calculated density is 6.30 g·cm−3. The results of six WDS analyses are Ir 29.30 (27.75–30.68), Rh 9.57 (8.46–10.71), Pt 1.85 (1.43–2.10), Ru 0.05 (0.02–0.07), Os 0.06 (0.03–0.13), Fe 13.09 (12.38–13.74), Ni 12.18 (11.78–13.12), Cu 6.30 (6.06–6.56), Co 0.06 (0.04–0.07), S 27.23 (26.14–27.89), for a total of 99.69 wt %. This composition corresponds to (Ir2.87Rh1.75Pt0.18Ru0.01Os0.01)Σ4.82(Fe4.41Ni3.90Cu1.87Co0.02)Σ10.20S15.98, calculated based on a total of 31 atoms per formula unit. The general formula is (Ir,Rh)5(Fe,Ni,Cu)10S16. Results of synchrotron micro-Laue diffraction studies indicate that tamuraite is trigonal. Its probable space group is R–3m (#166), and the unit-cell parameters are a = 7.073(1) Å, c = 34.277(8) Å, V = 1485(1) Å3, and Z = 3. The c:a ratio is 4.8462. The strongest eight peaks in the X-ray diffraction pattern [d in Å(hkl)(I)] are: 3.0106(26)(100), 1.7699(40)(71), 1.7583(2016)(65), 2.7994(205)(56), 2.9963(1010)(50), 5.7740(10)(45), 3.0534(20)(43) and 2.4948(208)(38). The crystal structure is derivative of pentlandite and related to that of oberthürite and torryweiserite. Tamuraite crystallized from a residual melt enriched in S, Fe, Ni, Cu, and Rh; these elements were incompatible in the Os–Ir alloy that nucleated in lode zones of chromitites in the Lysanskiy layered complex, Eastern Sayans, Russia. The name honors Nobumichi Tamura, senior scientist at the Advanced Light Source of the Lawrence Berkeley National Laboratory, Berkeley, California.

scholarly journals Maghemite in Brazilian Iron Ores: Quantification of the Magnetite-Maghemite Isomorphic Series by Χ-ray Diffraction and the Rietveld Method, and Confirmation by Independent Methods

Minerals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 346
Author(s):  
Renata Hiraga ◽  
Otávio Gomes ◽  
Reiner Neumann
Keyword(s):  
Solid Solution ◽  
Rietveld Method ◽  
Isomorphic Substitution ◽  
Iron Ores ◽  
Reflected Light ◽  
Magnetite Crystal ◽  
Brazilian Soils ◽  
Isomorphic Series ◽  
Ore Characterization ◽  
Ray Patterns

Maghemite (γ-Fe2O3) is a mineral formed from magnetite oxidation at low temperatures, an intermediate metastable term of the magnetite to hematite oxidation and could be mixed with both. It has magnetic susceptibility similar to magnetite, crystal structure close to magnetite with which it forms a solid solution, while compositionally it equals hematite. Maghemite is thus easily misidentified as magnetite by Χ-ray diffraction and/or as hematite by spot chemical analysis in iron ore characterization routines. Nonstoichiometric magnetite could be quantified in samples of Brazilian soils and iron ores by the Rietveld method using a constrained refinement of the Χ-ray patterns. The results were confirmed by reflected light microscopy and Raman spectroscopy, thus qualitatively validating the method. Χ-ray diffraction with the refinement of the isomorphic substitution of Fe2+ by Fe3+ along the magnetite-maghemite solid solution could help to suitably characterize maghemite in iron ores, allowing for the evaluation of its ultimate influence on mineral processing, as its effect on surface and breakage properties.

scholarly journals Remote Reflectivity Sensor for Industrial Applications

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1301
Author(s):  
Federico Cavedo ◽  
Parisa Esmaili ◽  
Michele Norgia
Keyword(s):  
Low Cost ◽  
Cost Effective ◽  
Industrial Applications ◽  
Interference Immunity ◽  
Surface Reflection ◽  
Measurement Systems ◽  
Digital Detector ◽  
Reflected Light ◽  
Surface Optical ◽  
Diffused Light

A low-cost optical reflectivity sensor is proposed in this paper, able to detect the presence of objects or surface optical properties variations, at a distance of up to 20 m. A collimated laser beam is pulsed at 10 kHz, and a synchronous digital detector coherently measures the back-diffused light collected through a 1-inch biconvex lens. The sensor is a cost-effective solution for punctual measurement of the surface reflection at different distances. To enhance the interference immunity, an algorithm based on a double-side digital baseline restorer is proposed and implemented to accurately detect the amplitude of the reflected light. As results show, the sensor is robust against ambient light and shows a strong sensitivity on a wide reflection range. The capability of the proposed sensor was evaluated experimentally for object detection and recognition, in addition to dedicated measurement systems, like remote encoders or keyphasors, realized far from the object to be measured.

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