scholarly journals The anatomy of the foveola reinvestigated

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4482 ◽  
Author(s):  
Alexander V. Tschulakow ◽  
Theo Oltrup ◽  
Thomas Bende ◽  
Sebastian Schmelzle ◽  
Ulrich Schraermeyer
Keyword(s):  
Light Beam ◽  
Focused Ion Beam ◽  
Light Transmission ◽  
Ion Beam ◽  
Incident Light ◽  
3D Structure ◽  
Müller Cells ◽  
Bright Spot ◽  
Muller Cells ◽  
Outer Segments

Objective In the foveola of the eye, photoreceptors and Müller cells with a unique morphology have been described, but little is known about their 3D structure and orientation. Considering that there is an angle-dependent change in the foveolar photoreceptor response for the same light beam, known as the Stiles Crawford Effect of the first kind (SCE I), which is still not fully understood, a detailed analysis of the anatomy of the foveolar cells might help to clarify this phenomenon. Methods Serial semithin and ultrathin sections, and focused ion beam (FIB) tomography were prepared from 32 foveolae from monkeys (Macaca fascicularis) and humans. Foveolae were also analyzed under the electron microscope. Serial sections and FIB analysis were then used to construct 3D models of central Müller and photoreceptor cells. In addition, we measured the transmission of collimated light under the light microscope at different angles after it had passed through human foveae from flat mounted isolated retinae. Results In monkeys, outer segments of central foveolar cones are twice as long as those from parafoveal cones and do not run completely parallel to the incident light. Unique Müller cells are present in the central foveolae (area of 200 µm in diameter) of humans and monkeys. Light entering the fovea center, which is composed only of cones and Müller cells, at an angle of 0° causes a very bright spot after passing through this area. However, when the angle of the light beam is changed to 10°, less light is measured after transpasssing through the retina, the foveolar center becomes darker and the SCE-like phenomenon is directly visible. Measurements of the intensities of light transmission through the central foveola for the incident angles 0 and 10° resemble the relative luminance efficiency for narrow light bundles as a function of the location where the beam enters the pupil as reported by Stiles and Crawford. The effect persisted after carefully brushing away the outer segments. Conclusion We show that unique cones and Müller cells with light fibre-like properties are present in the center of the fovea. These unique Müller cells cause an angle dependent, SCE-like drop in the intensity of light guided through the foveola. Outer segments from the foveolar cones of monkeys are not straight.

scholarly journals The anatomy of the foveola reinvestigated

2018 ◽  
Author(s):  
Alexander V. Tschulakow ◽  
Theo Oltrup ◽  
Thomas Bende ◽  
Sebastian Schmelzle ◽  
Ulrich Schraermeyer
Keyword(s):  
Light Beam ◽  
Focused Ion Beam ◽  
Light Transmission ◽  
Ion Beam ◽  
Incident Light ◽  
3D Structure ◽  
Müller Cells ◽  
Bright Spot ◽  
Muller Cells ◽  
Outer Segments

Objective. In the foveola of the eye, photoreceptors and Müller cells with a unique morphology have been described, but little is known about their 3D structure and orientation. Considering that there is an angle-dependent change in the foveolar photoreceptor response for the same light beam, known as the Stiles Crawford Effect of the first kind (SCE I), which is still not fully understood, a detailed analysis of the anatomy of the foveolar cells might help to clarify this phenomenon. Methods. Serial semithin and ultrathin sections, and focused ion beam (FIB) tomography were -prepared from 32 foveolae from monkeys (Macaca fascicularis) and humans. Foveolae were also analyzed under the electron microscope. Serial sections and FIB analysis were then used to construct 3D models of central Müller and photoreceptor cells. In addition, we measured the transmission of collimated light under the light microscope at different angles after it had passed through human foveae from flat mounted isolated retinae. Results. In monkeys, outer segments of central foveolar cones are twice as long as those from parafoveal cones and do not run completely parallel to the incident light. Unique Müller cells are present in the central foveolae (area of 200 µm in diameter) of humans and monkeys. Light entering the fovea center, which is composed only of cones and Müller cells, at an angle of 0 degrees causes a very bright spot after passing through this area. However, when the angle of the light beam is changed to 10 degrees, less light is measured after transpasssing through the retina, the foveolar center becomes darker and the SCE-like phenomenon is directly visible. Measurements of the intensities of light transmission through the central foveola for the incident angles 0 and 10 degrees resemble the relative luminance efficiency for narrow light bundles as a function of the location where the beam enters the pupil as reported by Stiles and Crawford. The effect persisted after carefully brushing away the outer segments. Conclusion. We show that unique cones and Müller cells with light fibre-like properties are present in the center of the fovea. These unique Müller cells cause an angle dependent, SCE-like drop in the intensity of light guided through the foveola. Outer segments from the foveola cones of monkeys are not straight.

scholarly journals The anatomy of the foveola reinvestigated

2018 ◽  
Author(s):  
Alexander V. Tschulakow ◽  
Theo Oltrup ◽  
Thomas Bende ◽  
Sebastian Schmelzle ◽  
Ulrich Schraermeyer
Keyword(s):  
Light Beam ◽  
Focused Ion Beam ◽  
Light Transmission ◽  
Ion Beam ◽  
Incident Light ◽  
3D Structure ◽  
Müller Cells ◽  
Bright Spot ◽  
Muller Cells ◽  
Outer Segments

Objective. In the foveola of the eye, photoreceptors and Müller cells with a unique morphology have been described, but little is known about their 3D structure and orientation. Considering that there is an angle-dependent change in the foveolar photoreceptor response for the same light beam, known as the Stiles Crawford Effect of the first kind (SCE I), which is still not fully understood, a detailed analysis of the anatomy of the foveolar cells might help to clarify this phenomenon. Methods. Serial semithin and ultrathin sections, and focused ion beam (FIB) tomography were -prepared from 32 foveolae from monkeys (Macaca fascicularis) and humans. Foveolae were also analyzed under the electron microscope. Serial sections and FIB analysis were then used to construct 3D models of central Müller and photoreceptor cells. In addition, we measured the transmission of collimated light under the light microscope at different angles after it had passed through human foveae from flat mounted isolated retinae. Results. In monkeys, outer segments of central foveolar cones are twice as long as those from parafoveal cones and do not run completely parallel to the incident light. Unique Müller cells are present in the central foveolae (area of 200 µm in diameter) of humans and monkeys. Light entering the fovea center, which is composed only of cones and Müller cells, at an angle of 0 degrees causes a very bright spot after passing through this area. However, when the angle of the light beam is changed to 10 degrees, less light is measured after transpasssing through the retina, the foveolar center becomes darker and the SCE-like phenomenon is directly visible. Measurements of the intensities of light transmission through the central foveola for the incident angles 0 and 10 degrees resemble the relative luminance efficiency for narrow light bundles as a function of the location where the beam enters the pupil as reported by Stiles and Crawford. The effect persisted after carefully brushing away the outer segments. Conclusion. We show that unique cones and Müller cells with light fibre-like properties are present in the center of the fovea. These unique Müller cells cause an angle dependent, SCE-like drop in the intensity of light guided through the foveola. Outer segments from the foveola cones of monkeys are not straight.

scholarly journals Spectral selectivity model for light transmission by the intermediate filaments in Müller cells

2017 ◽  
Vol 173 ◽  
pp. 282-290 ◽  
Author(s):  
Igor Khmelinskii ◽  
Tatiana Golubeva ◽  
Elena Korneeva ◽  
Mikhail Inyushin ◽  
Lidia Zueva ◽  
...  
Keyword(s):  
Intermediate Filaments ◽  
Light Transmission ◽  
Müller Cells ◽  
Muller Cells ◽  
Spectral Selectivity ◽  
Selectivity Model

Nano-structural changes in Li-ion battery cathodes during cycling revealed by FIB-SEM serial sectioning tomography

2015 ◽  
Vol 3 (35) ◽  
pp. 18171-18179 ◽  
Author(s):  
Bohang Song ◽  
Tan Sui ◽  
Siqi Ying ◽  
Liu Li ◽  
Li Lu ◽  
...  
Keyword(s):  
Structural Changes ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
3D Structure ◽  
Spherical Particles ◽  
Capacity Fading ◽  
Before And After ◽  
Electrochemical Cycling ◽  
Li Ion ◽  
Possible Cause

This study reports the feasibility of utilizing focused ion beam-scanning electron microscopy sectioning to reconstruct the 3D structure of electrodes before and after extended electrochemical cycling. The observed fragmentation of Li-rich layered spherical particles is speculated to be a possible cause of capacity fading.

3D Structure Fabrication by FIB Milling and Deposition

2006 ◽  
Vol 983 ◽  
Author(s):  
Toshiaki Fujii ◽  
Koji Iwasaki ◽  
Masanao Munekane ◽  
Yo Yamamoto ◽  
Toshitada Takeuchi ◽  
...  
Keyword(s):  
Focused Ion Beam ◽  
Ion Beam ◽  
3D Structure ◽  
Beam Current ◽  
Signal Generator ◽  
3D Structures ◽  
Nano Structures ◽  
Better Than

AbstractFocused Ion Beam (FIB) system is equipment used to make a wide variety of micro and Nano structures. Structures can be created using various materials by irradiating focused gallium ion beam on to the surface of specimens and by sputtering, etching and ion beam induced deposition. In order to realize greater diversity for nano construction by using the FIB system, we have developed technologies incorporating:- Built-in pattern signal generator- Multiple Gas Unit for gas assisted etching and beam induced deposition- A precision wheel for the stage.This latest FIB system has a narrow Ion beam with a diameter of better than 4nm. Beam current is controlled from 0.15pA to 20nA. These performances contribute significantly to the study 3D structures fabrication and modification.

scholarly journals Hybrid organic-inorganic perovskite metamaterial for light trapping and photon-to-electron conversion

Nanophotonics ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 3323-3333 ◽  
Author(s):  
Hao Jing ◽  
Yingying Zhu ◽  
Ru-Wen Peng ◽  
Cheng-Yao Li ◽  
Bo Xiong ◽  
...  
Keyword(s):  
Focused Ion Beam ◽  
High Efficiency ◽  
Light Trapping ◽  
Ion Beam ◽  
Incident Light ◽  
High Refractive Index ◽  
Cavity Modes ◽  
Flat Film ◽  
Electron Conversion ◽  
Phase Amplitude

AbstractDielectric metamaterials with high refractive indices may have an incredible capability to manipulate the phase, amplitude, and polarization of the incident light. Combining the high refractive index and the excellent electrical characteristics of the hybrid organic-inorganic perovskites (HOIPs), for the first time we experimentally demonstrate that metamaterial made of HOIPs can trap visible light and realize effective photon-to-electron conversion. The HOIP metamaterials are fabricated by focused ion beam milling on a solution-grown single-crystalline HOIP film. The optical absorption is significantly enhanced at the visible regime compared to that of the flat HOIP film, which originates from the excited Mie resonances and transverse cavity modes with inhibited interface reflection. Furthermore, compared to the flat film, the HOIP metamaterial shows increased photocurrent of up to ~40%, where the effective photocarrier generation efficiency increases by ~40% and the related internal efficiency by ~20%. Our data point to the potential application of HOIP metamaterials for high-efficiency light trapping and photon-to-electron conversion.

scholarly journals Human bone mesoscale 3D structure revisited by plasma focused ion beam serial sectioning

2020 ◽  
Author(s):  
Dakota Marie Binkley ◽  
Joseph Deering ◽  
Hui Yuan ◽  
Aurélien Gourrier ◽  
Kathryn Grandfield
Keyword(s):  
Large Scale ◽  
Focused Ion Beam ◽  
Bone Mineralization ◽  
Ion Beam ◽  
3D Structure ◽  
Three Dimensions ◽  
Lamellar Bone ◽  
Serial Sectioning ◽  
Important Challenge ◽  
Cellular Components

AbstractVisualizing bone mineralization and collagen microfibril organization at intermediate scales between the nanometer and the 100s of microns range, the mesoscale, is still an important challenge. Similarly, visualizing cellular components which locally affect the tissue structure requires a precision of a few tens of nanometers at maximum while spanning several tens of micrometers. To address this issue, we employed a plasma focused ion beam (PFIB) equipped with a scanning electron microscope (SEM) to sequentially section nanometer-scale layers of demineralized and mineralized human femoral lamellar bone over volumes of approximately 46 × 40 × 9 μm3, and 29 × 26 × 9 μm3, respectively. This large scale view retained high enough resolution to visualize the collagen microfibrils while partly visualizing the lacuno-canalicular network (LCN) in three-dimensions (3D). We showed that serial sectioning can be performed on mineralized sections, and does not require demineralization. Moreover, this method revealed ellipsoidal mineral clusters, noted by others in high resolution studies, as a ubiquitous motif in lamellar bone over tens of microns, suggesting a heterogeneous and yet regular pattern of mineral deposition past the single collagen fibril level. These findings are strong evidence for the need to revisit bone mineralization over multi-length scales.Graphical Abstract

scholarly journals Contribution of Müller cells toward the regulation of photoreceptor outer segment assembly

2004 ◽  
Vol 1 (3) ◽  
pp. 291-296 ◽  
Author(s):  
XIAOFEI WANG ◽  
ALESSANDRO IANNACCONE ◽  
MONICA M. JABLONSKI
Keyword(s):  
Outer Segment ◽  
Cell Function ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Müller Cells ◽  
Müller Cell ◽  
Muller Cells ◽  
Outer Segments ◽  
Pigment Epithelium Derived Factor ◽  
Muller Cell

The assembly of photoreceptor outer segments into stacked discs is a complicated process, the precise regulation of which remains a mystery. It is known that the integrity of the outer segment is heavily dependent upon surrounding cell types including the retinal pigment epithelium and Müller cells; however the role played by Müller cells within this photoreceptor-specific process has not been fully explored. Using an RPE-deprived but otherwise intact Xenopus laevis eye rudiment preparation, we reveal that Müller cell involvement in outer segment assembly is dependent upon the stimulus provided to the retina. Pigment epithelium-derived factor is able to support proper membrane folding after inhibition of Müller cell metabolism by alpha-aminoadipic acid, while isopropyl beta-D-thiogalactoside, a permissive glycan, requires intact Müller cell function. These results demonstrate that both intrinsic and extrinsic redundant mechanisms exist to support the ability of photoreceptors to properly assemble their outer segments. Our study further suggests that the receptor for pigment epithelium-derived factor resides in photoreceptors themselves while that for permissive glycans is likely localized to Müller cells, which in turn communicate with photoreceptors to promote proper membrane assembly.

scholarly journals Using Plasma Focused Ion Beam Microscopy to Characterize 3D Structure and Porosity of OPC Mortar

2019 ◽  
Vol 25 (S2) ◽  
pp. 926-927
Author(s):  
Peng Dong ◽  
Ali Allahverdi ◽  
Hui Yuan ◽  
Nabil D. Bassim
Keyword(s):  
Focused Ion Beam ◽  
Ion Beam ◽  
3D Structure
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