Influence of near-ultraviolet radiation on reproductive and immunological development in juvenile male Siberian hamsters

2001 ◽  
Vol 204 (14) ◽  
pp. 2535-2541
Author(s):  
George C. Brainard ◽  
John P. Hanifin ◽  
Felix M. Barker ◽  
Britt Sanford ◽  
Milton H. Stetson
Keyword(s):  
Monochromatic Light ◽  
Visible Spectrum ◽  
Short Photoperiod ◽  
Juvenile Male ◽  
Natural Habitats ◽  
Long Wavelength ◽  
Near Ultraviolet ◽  
Photoperiodic Regulation ◽  
Photon Pulse ◽  
Visible Wavelengths

SUMMARY The aim of this study was to characterize the lenticular ultraviolet transmission of the Siberian hamster (Phodopus sungorus) and to probe the range of near-ultraviolet (UV-A, 315–400nm) and visible wavelengths (400–760nm) for modulating the photoperiodic regulation of its reproductive and immune systems. Ocular lenses from adult hamsters were found to transmit UV-A wavelengths at similar levels to visible wavelengths, with a short-wavelength cut-off of 300nm. Five separate studies compared the responses of juvenile male hamsters to long photoperiods (16h:8h L:D), short photoperiods (10h:14h L:D) and short photoperiods interrupted by an equal photon pulse of monochromatic light of 320, 340, 360, 500 or 725nm during the night. The results show that UV-A wavelengths at 320, 340 and 360nm can regulate both reproductive and immune short-photoperiod responses as effectively as visible monochromatic light at 500nm. In contrast, long-wavelength visible light at 725nm did not block the short-photoperiod responses. These results suggest that both wavelengths in the visible spectrum, together with UV-A wavelengths, contribute to hamster photoperiodism in natural habitats.

An Infrared Microscope for Use on a Focused Ion Beam for Circuit Edit and Backside Edit Applications

2015 ◽  
Author(s):  
Alexander Richards ◽  
Matthew Weschler ◽  
Michael Durller
Keyword(s):  
Focused Ion Beam ◽  
Near Infrared ◽  
Ion Beam ◽  
Visible Spectrum ◽  
Camera System ◽  
Buried Structures ◽  
Ir Camera ◽  
Area Of Interest ◽  
Near Ultraviolet ◽  
Infrared Microscope

Abstract To help solve the navigational problem, i.e., being able to successfully locate a circuit for probing or editing without destroying chip functionality, a near-infrared (NIR), near-ultraviolet (NUV), and visible spectrum camera system was developed that attaches to most focused ion beam (FIB) or scanning electron microscope vacuum chambers. This paper reviews the details of the design and implementation of the NIR/NUV camera system, as instantiated upon the FEI FIB 200, with a particular focus on its use for the visualization of buried structures, and also for non-destructive real time area of interest location and end point detection. It specifically considers the use of the micro-optical camera system for its benefit in assisting with frontside and backside circuit edit, as well as other typical FIB milling activities. The quality of the image obtained by the IR camera rivals or exceeds traditional optical based imaging microscopy techniques.

Growth and Characterization of AllnGaN/InGaN Heterostructures

1996 ◽  
Vol 423 ◽  
Author(s):  
J. C. Roberts ◽  
F. G. Mcintosh ◽  
M. Aumer ◽  
V. Joshkin ◽  
K. S. Boutros ◽  
...  
Keyword(s):  
High Performance ◽  
Visible Spectrum ◽  
Growth Conditions ◽  
Light Emitting ◽  
Mocvd Growth ◽  
Near Ultraviolet ◽  
Active Layers ◽  
Double Heterostructures ◽  
Lattice Matched

AbstractThe emission wavelength of the InxGa1−xN ternary system can span from the near ultraviolet through red regions of the visible spectrum. High quality double heterostructures with these InxGa1−xN active layers are essential in the development of efficient optoelectronic devices such as high performance light emitting diodes and laser diodes. We will report on the MOCVD growth and characterization of thick and thin InGaN films. Thick InxGa1−xN films with values of x up to 0.40 have been deposited and their photoluminescence (PL) spectra measured. AlGaN/InGaN/AlGaN double heterostructures (DHs) have been grown that exhibit PL emission in the violet, blue, green and yellow spectral regions, depending on the growth conditions of the thin InGaN active layer. Preliminary results of an AllnGaN/InGaN/AllnGaN DH, with the potential of realizing a near-lattice matched structure, will also be presented.

scholarly journals Metalenses Based on Symmetric Slab Waveguide and c-TiO2: Efficient Polarization-Insensitive Focusing at Visible Wavelengths

Nanomaterials ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 699 ◽  
Author(s):  
Yaoyao Liang ◽  
Zhongchao Wei ◽  
Jianping Guo ◽  
Faqiang Wang ◽  
Hongyun Meng ◽  
...  
Keyword(s):  
Berry Phase ◽  
Incident Light ◽  
Visible Spectrum ◽  
Slab Waveguide ◽  
Optical Elements ◽  
Polarization Insensitive ◽  
Wavefront Shaping ◽  
Visible Wavelengths ◽  
532 Nm ◽  
Good Agreement

A key goal of metalens research is to achieve wavefront shaping of light using optical elements with thicknesses on the order of the wavelength. Here we demonstrate ultrathin highly efficient crystalline titanium dioxide metalenses at blue, green, and red wavelengths (λ0 = 453 nm, 532 nm, and 633 nm, respectively) based on symmetric slab waveguide theory. These metalenses are less than 488 nm-thick and capable of focusing incident light into very symmetric diffraction-limited spots with strehl ratio and efficiency as high as 0.96 and 83%, respectively. Further quantitative characterizations about metalenses’ peak focusing intensities and focal spot sizes show good agreement with theoretical calculation. Besides, the metalenses suffer only about 10% chromatic deviation from the ideal spots in visible spectrum. In contrast with Pancharatnam–Berry phase mechanism, which limit their incident light at circular polarization, the proposed method enables metalenses polarization-insensitive to incident light.

Thin-film Photodiode with an a-Si:H/nc-Si:H Absorption Bilayer

2011 ◽  
Vol 1321 ◽  
Author(s):  
Y. Vygranenko ◽  
M. Vieira ◽  
A. Sazonov
Keyword(s):  
Thin Film ◽  
Leakage Current ◽  
Near Infrared ◽  
Spectral Response ◽  
Nanocrystalline Silicon ◽  
Depletion Region ◽  
Long Wavelength ◽  
Near Ultraviolet ◽  
High Bias ◽  
Bias Range

ABSTRACTWe report on the fabrication and characterization of n+-n-i-δi-p thin-film photodiodes with an active region comprising a hydrogenated nanocrystalline silicon (nc-Si:H) n-layer and a hydrogenated amorphous silicon (a-Si:H) i-layer. The combination of wide- and narrow-gap absorption layers enables the spectral response extending from the near-ultraviolet (NUV) to the near-infrared (NIR) region. Moreover, in the low-bias range, when only the i-layer is depleted, the leakage current is significantly lower than that in the conventional nc-Si:H n+-n-p+ photodiode deposited under the same deposition conditions. Device with the 900nm/400nm thick n-i-layers exhibits a reverse dark current density of 3 nA/cm2 at −1V. In the high-bias range, when the depletion region expands within the n-layer, the magnitude of the leakage current depends on electronic properties of nc-Si:H. The density of shallow and deep states, and diffusion length of holes in the n-layer have been estimated from the capacitance-voltage characteristics and from the bias dependence of the long-wavelength response, respectively. To improve the quantum efficiency in the NIR-region, we have also implemented a Cr / ZnO:Al back reflector. The observed long-wavelength spectral response is about twice as high as that for a reference photodiode without ZnO:Al layer. Results demonstrate the feasibility of the photodiode for low-level light detection in the NUV-to-NIR spectral range.

scholarly journals Environment and Sporulation in Phytopathogenic Fungi IV. The Effect of Light on the- Formation of Conidia of Peronospora Tabacina Adam

1963 ◽  
Vol 16 (1) ◽  
pp. 88 ◽  
Author(s):  
IAM Cruickshank
Keyword(s):  
Light Source ◽  
Monochromatic Light ◽  
Continuous Light ◽  
Visible Spectrum ◽  
Phytopathogenic Fungi ◽  
Time Of Day ◽  
Light Conditions ◽  
Low Light ◽  
Maximal Inhibition ◽  
Effect Of Light

Using a leaf�disk technique, an analysis of the effect of light on the sporulation intensity of P. tabacina was carried out. The following points were demonstrated: (I) Under conditions of continuous light, sporulation of P. tabacina is sensitive to very low light intensities. ED5!1 for inhibition of sporulation was 16 ftvV cm- 2 for incandescent light (4 f,c.), and 0�58 p.W cm-2 for a monochromatic light source (469 mpo) in the region of maximum effectiveness. (2) Dark treatments induced sporulation under otherwise continuous light conditions. The response was directly proportional to the length of the exposure to darkness over the period 1�5-7 hr. (3) The time of day at which sporulation occurred could be modified by adjustment of the time of day at which darkness was initiated. (4) Within the visible spectrum, the region exerting maximal inhibition on sporulation occurred at 450-525 mJL.

scholarly journals Magnetic compass orientation in European robins is dependent on both wavelength and intensity of light

2002 ◽  
Vol 205 (24) ◽  
pp. 3845-3856 ◽  
Author(s):  
Rachel Muheim ◽  
Johan Bäckman ◽  
Susanne Åkesson
Keyword(s):  
Transition Zone ◽  
Wavelength Range ◽  
Short Wavelength ◽  
Monochromatic Light ◽  
Magnetic Compass ◽  
Autumn Migration ◽  
Compass Orientation ◽  
Long Wavelength ◽  
Magnetic Compass Orientation ◽  
And Shifts

SUMMARYMagnetic compass orientation in birds has been shown to be light dependent. Results from behavioural studies indicate that magnetoreception capabilities are disrupted under light of peak wavelengths longer than 565 nm, and shifts in orientation have been observed at higher light intensities(43-44×1015 quanta s-1 m-2). To investigate further the function of the avian magnetic compass with respect to wavelength and intensity of light, we carried out orientation cage experiments with juvenile European robins, caught during their first autumn migration,exposed to light of 560.5 nm (green), 567.5 nm (green-yellow) and 617 nm (red)wavelengths at three different intensities (1 mW m-2, 5 mW m-2 and 10 mW m-2). We used monochromatic light of a narrow wavelength range (half bandwidth of 9-11 nm, compared with half bandwidths ranging between 30 nm and 70 nm used in other studies) and were thereby able to examine the magnetoreception mechanism in the expected transition zone between oriented and disoriented behaviour around 565 nm in more detail. We show (1) that European robins show seasonally appropriate migratory directions under 560.5 nm light, (2) that they are completely disoriented under 567.5 nm light under a broad range of intensities, (3) that they are able to orient under 617 nm light of lower intensities, although into a direction shifted relative to the expected migratory one, and (4) that magnetoreception is intensity dependent, leading to disorientation under higher intensities. Our results support the hypothesis that birds possess a light-dependent magnetoreception system based on magnetically sensitive,antagonistically interacting spectral mechanisms, with at least one high-sensitive short-wavelength mechanism and one low-sensitive long-wavelength mechanism.

scholarly journals The Spectral Sensitivity of Crayfish and Lobster Vision

1961 ◽  
Vol 44 (6) ◽  
pp. 1089-1102 ◽  
Author(s):  
Donald Kennedy ◽  
Merle S. Bruno
Keyword(s):  
Fresh Water ◽  
Spectral Sensitivity ◽  
Light Adaptation ◽  
Compound Eye ◽  
Monochromatic Light ◽  
Sensitivity Function ◽  
Visual Sensitivity ◽  
Long Wavelength ◽  
Cone Pigments ◽  
Sensitivity Data

(1) The spectral sensitivity function for the compound eye of the crayfish has been determined by recording the retinal action potentials elicited by monochromatic stimuli. Its peak lies at approximately 570 mµ. (2) Similar measurements made on lobster eyes yield functions with maxima in the region of 520 to 525 mµ, which agree well with the absorption spectrum of lobster rhodopsin if minor allowances are made for distortion by known screening pigments. (3) The crayfish sensitivity function, since it is unaffected by selective monochromatic light adaptation, must be determined by a single photosensitive pigment. The absorption maximum of this pigment may be inferred with reasonable accuracy from the sensitivity data. (4) The visual pigment of the crayfish thus has its maximum absorption displaced by 50 to 60 mµ towards the red end of the spectrum from that of the lobster and other marine crustacea. This shift parallels that found in both rod and cone pigments between fresh water and marine vertebrates. In the crayfish, however, an altered protein is responsible for the shift and not a new carotenoid chromophore as in the vertebrates. (5) The existence of this situation in a new group of animals (with photoreceptors which have been evolved independently from those of vertebrates) strengthens the view that there may be strong selection for long wavelength visual sensitivity in fresh water.

scholarly journals Melamine Faced Panels Defect Classification beyond the Visible Spectrum

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 3644
Author(s):  
Cristhian Aguilera ◽  
Cristhian Aguilera ◽  
Angel Sappa
Keyword(s):  
Near Infrared ◽  
Visible Spectrum ◽  
Local Binary Patterns ◽  
Classification Performance ◽  
Support Vector ◽  
Feature Descriptor ◽  
Long Wavelength ◽  
Spectral Bands ◽  
Image Set ◽  
Long Wavelength Infrared

In this work, we explore the use of images from different spectral bands to classify defects in melamine faced panels, which could appear through the production process. Through experimental evaluation, we evaluate the use of images from the visible (VS), near-infrared (NIR), and long wavelength infrared (LWIR), to classify the defects using a feature descriptor learning approach together with a support vector machine classifier. Two descriptors were evaluated, Extended Local Binary Patterns (E-LBP) and SURF using a Bag of Words (BoW) representation. The evaluation was carried on with an image set obtained during this work, which contained five different defect categories that currently occurs in the industry. Results show that using images from beyond the visual spectrum helps to improve classification performance in contrast with a single visible spectrum solution.

scholarly journals Measurement of rotatory dispersive power in the visible and ultra-violet regions of the spectrum

1908 ◽  
Vol 81 (550) ◽  
pp. 472-474 ◽  
Keyword(s):  
Photographic Plate ◽  
Monochromatic Light ◽  
Green Light ◽  
Visible Spectrum ◽  
Ultra Violet ◽  
Narrow Strip ◽  
In Series ◽  
Limited Scale ◽  
Dispersive Power ◽  
Constant Deviation

The following is a brief preliminary account of improvements effected in the method of determining rotatory dispersive power which have made it possible to observe accurately not only in the bright regions of the visible spectrum, but throughout the scale from the region of the lithium red line into that commanded by the photographic plate. Two methods have generally been used for the purpose, namely, (1) Broch’s method, in which a spectroscope is arranged in series with the polarimeter and a narrow strip of a continuous spectrum is picked out for observation—a method which is much improved by using a constant-deviation spectroscope in place of one of the variable-deviation type, and .(2) Landolt’s method, in which a white light is reduced by means of filters to approximate homogeneity in the red, green, light-blue, or dark-blue parts of the spectrum. Neither method fulfils the fundamental condition that the field of the polarimeter shall be uniformly lighted with monochromatic light—many of the measurements that have been made, therefore, possess only a qualitative value. A much better method is due to the late Sir William Perkin, who introduced the use of a spectroscope-eyepiece as a means of purifying the sodium light, and used it on a limited scale for measuring rotatory dispersive power in the red (lithium), yellow (sodium), and green, thallium) parts of the spectrum.

THE SPECIFIC EFFECTS OF MONOCHROMATIC LIGHT ON THE GROWTH OF YEAST

1930 ◽  
Vol 2 (4) ◽  
pp. 249-263 ◽  
Author(s):  
A. H. Hutchinson ◽  
Dorothy Newton
Keyword(s):  
Growth Rate ◽  
Rapid Growth ◽  
Monochromatic Light ◽  
Visible Spectrum ◽  
Ultra Violet ◽  
Light Stimulation ◽  
Specific Effects ◽  
Rapid Growth Rate ◽  
Sudden Transition

An isolated strain of Yeast, derived from Fleischman's preparation, when exposed to monochromatic light responds quite differently to light of different wave-lengths. Slight retardation in growth by red and orange light, stimulation by yellow and green, and increasingly marked retardation in the blue and violet, characterize the effects of the mercury lines of the visible spectrum. There is a sudden transition to stimulation in the near ultra-violet. (λ 3984 Å). Stimulation continues at λ 3650 Å and characterises the region λ 2894 Å to λ 2700 Å, but otherwise the lines employed in this investigation retard growth.Generally the effect either of stimulation or retardation is greater when the control is one of rapid growth rate, but the reverse is the case at the red end of the visible spectrum.

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