scholarly journals The optics of the human eye at 8.6 μm lateral resolution

2021 ◽  
Author(s):  
Sergio Bonaque-Gonzalez ◽  
Juan M. Trujillo-Sevilla ◽  
Miriam Velasco-Ocana ◽  
Oscar Casanova-Gonzalez ◽  
Miguel Sicilia-Cabrera ◽  
...  
Keyword(s):  
Pupil Diameter ◽  
Current Measurement ◽  
Human Vision ◽  
Lateral Resolution ◽  
Measurement Systems ◽  
Human Eye ◽  
New Information ◽  
Normal Human ◽  
The Way

Ocular optics is normally estimated based on 2,600 measurement points within the pupil of the eye, which implies a lateral resolution of approximately 175 microns for a 9 mm pupil diameter. This is because information below this resolution is not thought to be relevant or even possible to obtain with current measurement systems. In this work, we characterize the in vivo ocular optics of the human eye with a lateral resolution of 8.6 microns, which implies roughly 1 million measurement points for a pupil diameter of 9 mm. The results suggest that the normal human eye presents a series of hitherto unknown optical patterns with amplitudes between 200 and 300 nm and is made up of a series of in-phase peaks and valleys. If the results are analysed at only high lateral frequencies, the human eye is also found to contain a whole range of new information. This discovery could have a great impact on the way we understand some fundamental mechanisms of human vision and could be of outstanding utility in certain fields of ophthalmology.

scholarly journals The optics of the human eye at 8.6 µm resolution

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sergio Bonaque-González ◽  
Juan M. Trujillo-Sevilla ◽  
Miriam Velasco-Ocaña ◽  
Óscar Casanova-González ◽  
Miguel Sicilia-Cabrera ◽  
...  
Keyword(s):  
Pupil Diameter ◽  
Current Measurement ◽  
Human Vision ◽  
Lateral Resolution ◽  
Measurement Systems ◽  
Human Eye ◽  
New Information ◽  
Normal Human ◽  
The Way

AbstractOcular optics is normally estimated based on up to 2,600 measurement points within the pupil of the eye, which implies a lateral resolution of approximately 175 µm for a 9 mm pupil diameter. This is because information below this resolution is not thought to be relevant or even possible to obtain with current measurement systems. In this work, we characterize the in vivo ocular optics of the human eye with a lateral resolution of 8.6 µm, which implies roughly 1 million measurement points for a pupil diameter of 9 mm. The results suggest that the normal human eye presents a series of hitherto unknown optical patterns with amplitudes between 200 and 300 nm and is made up of a series of in-phase peaks and valleys. If the results are analysed at only high lateral frequencies, the human eye is also found to contain a whole range of new information. This discovery could have a great impact on the way we understand some fundamental mechanisms of human vision and could be of outstanding utility in certain fields of ophthalmology.

Positing Nonconceptual Representations

2017 ◽  
Author(s):  
Karen Neander
Keyword(s):  
Cognitive Science ◽  
Young Woman ◽  
Theoretical Work ◽  
Human Vision ◽  
Psychological Process ◽  
Central Tenet ◽  
Normal Human ◽  
Visual Targets ◽  
Work Done ◽  
The Way

In the second chapter, the author describes some research by cognitive scientists, who posit nonconceptual representations to explain certain perceptual capacities (and incapacities). This research and the way in which it is reported illustrate the type of theoretical work done by an error-permitting notion of nonconceptual representation, alongside a malfunction-permitting notion of function. One set of studies (led by McCloskey) that is described in some detail focuses on an unusual deficit in locating visual targets (in a young woman, AH), which were intended to contribute to understanding normal human vision. The author makes clear why the contents ascribed to the underlying representational states, where the errors first occur, are referential-intentional contents, not merely (natural-factive) informational contents, and why their ascriptions count as intensional, according to standard criteria. Toward the end of the chapter, the author reminds readers of a familiar conundrum: if a representation’s having content is not causally potent in a psychological process, why is it (still) a central tenet of mainstream cognitive science that such a process should be understood as representational?

scholarly journals Scanning Slit Confocal Microscopy of the Living Eye

1994 ◽  
Vol 2 (8) ◽  
pp. 3-4
Author(s):  
Barry D. Masters
Keyword(s):  
Real Time ◽  
Optical Design ◽  
Front Surface ◽  
Confocal Microscope ◽  
Human Cornea ◽  
The Real ◽  
Human Eye ◽  
Time Scanning ◽  
Normal Human

The living human eye is in constant motion. The cornea, which is the transparent front surface of the eyeball, is a formidable specimen for microscopy. How can we use a microscope to obtain sufficient contrast in order to observe cellular and subcellular details on a moving, transparent specimen? Although the normal human cornea is free of blood vessels, there are many nerves within the 500 μm thickness of this tissue. How can we observe these nerves in the living human eye?To accomplish these aims, use a new real-time, scanning slit confocal microscope that was developed by Dr. A. Thaer for imaging the in vivo human cornea. The optical design of the real-time, scanning slit confocal microscope is shown as follows in Figure 1. The confocal microscope is a modification of the real-time, scanning slit confocal microscope based on an oscillating too-sided mirror (bi-lateral scanning) which was designed and first constructed in 1969 by G. M. Svishchev in Lenningrad.

Ultrastructural modification of cellular interactions in cancer tumor

1978 ◽  
Vol 36 (2) ◽  
pp. 318-319
Author(s):  
N. P. Dmitrieva
Keyword(s):  
Cancer Cells ◽  
Human Thyroid ◽  
Adjacent Cell ◽  
Main Role ◽  
Cellular Interactions ◽  
Electron Microscopic ◽  
Cancer Tumor ◽  
Normal Human ◽  
Characteristic Features

One of the most characteristic features of cancer cells is their ability to metastasia. It is suggested that the modifications of the structure and properties of cancer cells surfaces play the main role in this process. The present work was aimed at finding out what ultrastructural features apear in tumor in vivo which removal of individual cancer cells from the cell population can provide. For this purpose the cellular interactions in the normal human thyroid and cancer tumor of this gland electron microscopic were studied. The tissues were fixed in osmium tetroxide and were embedded in Araldite-Epon.In normal human thyroid the most common type of intercellular contacts was represented by simple junction formed by the parallelalignment of adjacent cell membranees leaving in between an intermembranes space 15-20 nm filled with electronlucid material (Fig. 1a). Sometimes in the basal part of cells dilatations of the intercellular space 40-50 nm wide were found (Fig. 1a). Here the cell surfaces may form single short microvilli.

Presence and Possible Origin of ɛ(γ-Glutamyl)Lysine Isodipeptide in Human Plasma

1992 ◽  
Vol 67 (01) ◽  
pp. 060-062 ◽  
Author(s):  
J Harsfalvi ◽  
E Tarcsa ◽  
M Udvardy ◽  
G Zajka ◽  
T Szarvas ◽  
...  
Keyword(s):  
Human Plasma ◽  
Fibrinolytic Therapy ◽  
Normal Human Plasma ◽  
Normal Human ◽  
Hplc Technique ◽  
Significant Change

Summaryɛ(γ-glutamyl)lysine isodipeptide has been detected in normal human plasma by a sensitive HPLC technique in a concentration of 1.9-3.6 μmol/1. Incubation of in vitro clotted plasma at 37° C for 12 h resulted in an increased amount of isodipeptide, and there was no further significant change when streptokinase was also present. Increased in vivo isodipeptide concentrations were also observed in hypercoagulable states and during fibrinolytic therapy.

scholarly journals Mass spectrometry based metabolomics of volume-restricted in-vivo brain samples: actual status and the way forward

2021 ◽  
pp. 116365
Author(s):  
Marlien van Mever ◽  
Karen Segers ◽  
Debby Mangelings ◽  
Thomas Hankemeier ◽  
Yvan Vander Heyden ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
The Way

Meet me halfway: Are in vitro 3D cancer models on the way to replace in vivo models for nanomedicine development?

2021 ◽  
Author(s):  
Sabina Pozzi ◽  
Anna Scomparin ◽  
Sahar Israeli-Dangoor ◽  
Daniel Rodriguez ◽  
Paula Ofek ◽  
...  
Keyword(s):  
In Vivo Models ◽  
Cancer Models ◽  
The Way

Toxicokinetic and Genotoxicity Study of NNK in Male Sprague-Dawley Rats Following Nose-Only Inhalation Exposure, Intraperitoneal Injection, and Oral Gavage

2021 ◽  
Author(s):  
Shu-Chieh Hu ◽  
Matthew S Bryant ◽  
Estatira Sepehr ◽  
Hyun-Ki Kang ◽  
Raul Trbojevich ◽  
...  
Keyword(s):  
Human Lung ◽  
Inhalation Exposure ◽  
Systemic Exposure ◽  
Sprague Dawley ◽  
Oral Gavage ◽  
Sd Rats ◽  
New Information ◽  
Sprague Dawley Rats ◽  
Tissue Specimens

Abstract The tobacco-specific nitrosamine NNK [4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone] is found in tobacco products and tobacco smoke. NNK is a potent genotoxin and human lung carcinogen; however, there are limited inhalation data for the toxicokinetics (TK) and genotoxicity of NNK in vivo. In the present study, a single dose of 5x10−5, 5x10−3, 0.1, or 50 mg/kg body weight (BW) of NNK, 75% propylene glycol (vehicle control), or air (sham control) was administered to male Sprague-Dawley (SD) rats (9-10 weeks age) via nose-only inhalation (INH) exposure for 1 hour. For comparison, the same doses of NNK were administered to male SD rats via intraperitoneal (IP) injection and oral gavage (PO). Plasma, urine, and tissue specimens were collected at designated timepoints and analyzed for levels of NNK and its major metabolite 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) and tissue levels of DNA adduct O6-methylguanine by LC/MS/MS. TK data analysis was performed using a non-linear regression program. For the genotoxicity subgroup, tissues were collected at 3 hours post-dosing for comet assay analysis. Overall, the TK data indicated that NNK was rapidly absorbed and metabolized extensively to NNAL after NNK administration via the three routes. The IP route had the greatest systemic exposure to NNK. NNK metabolism to NNAL appeared to be more efficient via INH than IP or PO. NNK induced significant increases in DNA damage in multiple tissues via the three routes. The results of this study provide new information and understanding of the toxicokinetics and genotoxicity of NNK.

scholarly journals Bone marrow stromal fibroblasts secrete interleukin-6 and granulocyte- macrophage colony-stimulating factor in the absence of inflammatory stimulation: demonstration by serum-free bioassay, enzyme-linked immunosorbent assay, and reverse transcriptase polymerase chain reaction

Blood ◽  
1992 ◽  
Vol 80 (5) ◽  
pp. 1190-1198 ◽  
Author(s):  
SC Guba ◽  
CI Sartor ◽  
LR Gottschalk ◽  
YH Jing ◽  
T Mulligan ◽  
...  
Keyword(s):  
Human Serum ◽  
Enzyme Linked Immunosorbent Assay ◽  
Stromal Fibroblasts ◽  
Gm Csf ◽  
Normal Human ◽  
Macrophage Colony Stimulating Factor ◽  
Polymerase Chain ◽  
Macrophage Colony ◽  
Stimulating Factor

Abstract Bone marrow (BM) stromal fibroblasts produce hematopoietic growth factors (HGFs) in response to inflammatory mediators such as tumor necrosis factor-alpha or interleukin-1 alpha (IL-1 alpha). In the absence of such inflammatory stimuli, production of HGFs by BM stromal cells has been problematic and controversial. In vivo, however, basal hematopoiesis maintains blood counts within a normal homeostatic range even in the absence of inflammation, and HGFs are required for progenitor cell differentiation in vitro. To better ascertain the contribution of BM stromal fibroblasts to basal hematopoiesis, we therefore studied HGF production in quiescent BM stromal fibroblasts by three sensitive assays: serum-free bioassay, enzyme-linked immunosorbent assay, and reverse transcriptase polymerase chain reaction. Stromal fibroblasts were cultured in the presence or absence of normal human serum to determine if serum factor(s) present in the noninflammatory (basal) state induce secretion of HGFs. Human serum was found to induce or enhance transcription and secretion of granulocyte- macrophage colony-stimulating factor (GM-CSF) and enhance secretion of constitutively expressed IL-6. In contrast, no secretion of either granulocyte-CSF (G-CSF) or IL-3 was found. These data indicate that factors in normal human serum are active in enhancing GM-CSF and IL-6 production by stromal fibroblasts and suggest that these growth factors contribute to the maintainance of normal, basal hematopoiesis in vivo.

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