scholarly journals Vitamin B12: A Tunable, Long Wavelength, Light-Responsive Platform for Launching Therapeutic Agents

2015 ◽  
Vol 48 (11) ◽  
pp. 2866-2874 ◽  
Author(s):  
Thomas A. Shell ◽  
David S. Lawrence
Keyword(s):  
Vitamin B12 ◽  
Therapeutic Agents ◽  
Long Wavelength ◽  
Wavelength Light

scholarly journals Demonstration of epitaxial growth of strain-relaxed GaN films on graphene/SiC substrates for long wavelength light-emitting diodes

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Ye Yu ◽  
Tao Wang ◽  
Xiufang Chen ◽  
Lidong Zhang ◽  
Yang Wang ◽  
...  
Keyword(s):  
Epitaxial Growth ◽  
Light Emitting Diodes ◽  
Nitrogen Plasma ◽  
Biaxial Stress ◽  
Organic Chemical ◽  
Graphene Surface ◽  
Light Emitting ◽  
Long Wavelength ◽  
Pre Treatment ◽  
Wavelength Light

AbstractStrain modulation is crucial for heteroepitaxy such as GaN on foreign substrates. Here, the epitaxy of strain-relaxed GaN films on graphene/SiC substrates by metal-organic chemical vapor deposition is demonstrated. Graphene was directly prepared on SiC substrates by thermal decomposition. Its pre-treatment with nitrogen-plasma can introduce C–N dangling bonds, which provides nucleation sites for subsequent epitaxial growth. The scanning transmission electron microscopy measurements confirm that part of graphene surface was etched by nitrogen-plasma. We study the growth behavior on different areas of graphene surface after pre-treatment, and propose a growth model to explain the epitaxial growth mechanism of GaN films on graphene. Significantly, graphene is found to be effective to reduce the biaxial stress in GaN films and the strain relaxation improves indium-atom incorporation in InGaN/GaN multiple quantum wells (MQWs) active region, which results in the obvious red-shift of light-emitting wavelength of InGaN/GaN MQWs. This work opens up a new way for the fabrication of GaN-based long wavelength light-emitting diodes.

Light Trapping in Thin Film Silicon n-i-p Solar Cells - Gains and Losses

2008 ◽  
Vol 1101 ◽  
Author(s):  
Ruud E.I. Schropp ◽  
Hongbo Li ◽  
Jatin K. Rath ◽  
Ronald H. Franken
Keyword(s):  
Thin Film ◽  
Light Trapping ◽  
Structural Defects ◽  
Metallic Surface ◽  
Textured Surfaces ◽  
Long Wavelength ◽  
Thin Film Silicon ◽  
Internal Surfaces ◽  
Gains And Losses ◽  
Wavelength Light

AbstractThin film silicon solar cell technology frequently makes use of rough or textured surfaces in order to enhance light absorption within the thin absorber layers by scattering and total internal reflection (“light trapping”). The rough morphology of the optically functional internal surfaces both in superstrate and substrate cells however, not only has a beneficial effect on light scattering properties, but on the other hand may also have deleterious effects on the microscopic structure of the deposited layers, in particular if these layers are nanocrystalline. The narrow valleys in the surface morphology may lead to structural defects, such as cavities and pinholes. By adjusting the morphology, these defects can be avoided.However, even when structural defects in layers directly deposited on rough interfaces are avoided, the obtained optically defined maximum current density is still much lower than expected. For instance, in n-i-p structures the rough interface (the textured back reflector consisting of nanostructured Ag coated with ZnO) is located at the back of the cell, where only long wavelength light is present. The natively textured Ag film is sputtered at elevated temperature and optimized for diffusely reflecting this long wavelength light. From experiments we infer that the nanostructured metallic surface also gives rise to plasmon absorption in the red and near IR, and that this leads to a parasitic absorption, i.e. at least part of the absorbed energy is not re-emitted to the active layers.

scholarly journals The hyperopic effect of narrow-band long-wavelength light in tree shrews increases non-linearly with duration

2018 ◽  
Vol 146-147 ◽  
pp. 9-17 ◽  
Author(s):  
Alexander H. Ward ◽  
Thomas T. Norton ◽  
Carrie E. Huisingh ◽  
Timothy J. Gawne
Keyword(s):  
Narrow Band ◽  
Tree Shrews ◽  
Long Wavelength ◽  
Wavelength Light

Practical infra-red illumination and observation techniques for wildlife studies using ICI-962 perspex

2003 ◽  
Vol 25 (2) ◽  
pp. 201 ◽  
Author(s):  
C Marks ◽  
F Busana ◽  
F Gigliotti ◽  
M Lindeman
Keyword(s):  
Uv Light ◽  
Ultra Violet ◽  
Ir Radiation ◽  
Long Wavelength ◽  
Non Invasive ◽  
Radiation Sources ◽  
Infra Red ◽  
Invaluable Tool ◽  
Free Ranging ◽  
Wavelength Light

MAMMALS do not normally visually perceive infrared (IR) or ultra-violet (UV) light that exists on either side of the visual spectrum from 390 to 760 nanometers (nm) (Wolken 1975). There is no evidence to suggest that nocturnal mammals have become more sensitive to long wavelength light as an adaptive response (Lythgoe 1979), although some reptiles can sense longer wavelength, thermal IR radiation (Barrett et al. 1970). Because it is not perceived, and is unlikely to affect animal behaviour, IR observation can be an invaluable tool for wildlife researchers. This paper describes the construction and use of simple IR radiation sources that can be used for non-invasive behavioural observations of captive and free-ranging mammals.

Facile synthesis of yellow fluorescent carbon dots for highly sensitive sensing of cobalt ions and biological imaging

2019 ◽  
Vol 11 (32) ◽  
pp. 4077-4083 ◽  
Author(s):  
Min Tian ◽  
Yaoming Liu ◽  
Yingte Wang ◽  
Yong Zhang
Keyword(s):  
Light Emission ◽  
Biological Imaging ◽  
Cobalt Ions ◽  
Long Wavelength ◽  
Scattering Effects ◽  
Highly Sensitive ◽  
Penetration Ability ◽  
Weak Light ◽  
Fluorescent Carbon Dots ◽  
Wavelength Light

Long-wavelength light emission has been garnering extensive attention in terms of strong tissue penetration ability and weak light scattering effects.

scholarly journals Upconversion nanoparticle as a theranostic agent for tumor imaging and therapy

2016 ◽  
Vol 09 (04) ◽  
pp. 1630006 ◽  
Author(s):  
Wenkai Fang ◽  
Yanchun Wei
Keyword(s):  
Optical Properties ◽  
Tumor Imaging ◽  
Promising Material ◽  
Upconversion Nanoparticles ◽  
Multiphoton Absorption ◽  
Long Wavelength ◽  
Visible Wavelength ◽  
Theranostic Agent ◽  
Challenges And Opportunities ◽  
Wavelength Light

Upconversion nanoparticles (UCNPs) as a promising material are widely studied due to their unique optical properties. The material can be excited by long wavelength light and emit visible wavelength light through multiphoton absorption. This property makes the particles highly attractive candidates for bioimaging and therapy application. This review aims at summarizing the synthesis and modification of UCNPs, especially the applications of UCNPs as a theranostic agent for tumor imaging and therapy. The biocompatibility and toxicity of UCNPs are also further discussed. Finally, we discuss the challenges and opportunities in the development of UCNP-based nanoplatforms for tumor imaging and therapy.

An anomaly in the response of the eye to light of short wavelengths

1977 ◽  
Vol 278 (960) ◽  
pp. 207-240 ◽  
Keyword(s):  
Field Experiment ◽  
Spectral Sensitivity ◽  
Large Range ◽  
Fusion Frequency ◽  
Long Wavelength ◽  
Human Eye ◽  
Vision Experiment ◽  
Wavelength Light

Adaptation of the human eye to long-wavelength light leaves it insensitive to short-wavelengths: a blue flash that is visible in the presence of a yellow adapting field may remain invisible for several seconds after the field has been turned off (see experiment 1 and Appendix). This ‘transient tritanopia’ occurs for a large range of adapting intensities, but is abolished if the adapting field is very bright (experiment 2). The loss of sensitivity is primarily confined to the blue-sensitive cone mechanism (experiments 2 a , 3 and 4 ; and Appendix) and can be produced by small attenuations of the adapting field (experiment 5). It occurs in both foveal and parafoveal vision (experiment 6) but is absent when adapting and test stimuli are presented to opposite eyes (experiment 7). It was found in a protanope (experiment 9 a ) and, in a modified form, in a deuteranope (experiment 9 b ). No differences in sensitivity were found for blue flashes presented in the light and dark phases of a field flickering at a rate above the fusion frequency (Appendix). The sensitivity of the blue-sensitive mechanism of the eye appears to be controlled not only by quanta absorbed by the blue receptors but also by a mechanism with a different spectral sensitivity

scholarly journals Euphausiid visual pigments. The rhodopsins of Euphausia superba and Meganyctiphanes norvegica (Crustacea, Euphausiacea).

1982 ◽  
Vol 80 (3) ◽  
pp. 451-472 ◽  
Author(s):  
C J Denys ◽  
P K Brown
Keyword(s):  
Schiff Base ◽  
Euphausia Superba ◽  
Visual Pigments ◽  
Long Wavelength ◽  
Spectral Changes ◽  
Accessory Pigment ◽  
Meganyctiphanes Norvegica ◽  
Ph Dependent ◽  
Wavelength Light ◽  
Absorbance Spectra

The rhabdoms of Euphausia superba contain one digitonin-extractable rhodopsin, lambda max 485 nm. The rhodopsin undergoes unusual pH-dependent spectral changes: above neutrality, the absorbance decreases progressively at 485 nm and rises near 370 nm. This change is reversible and appears to reflect an equilibrium between a protonated and an unprotonated form of the rhodopsin Schiff-base linkage. Near neutral pH and at 10 degrees C, the rhodopsin is partiaLly converted by 420-nm light to a stable 493-nm metarhodopsin. The metarhodopsin is partially photoconverted to rhodopsin by long-wavelength light in the absence of NH2OH; in the presence of NH2OH, it is slowly converted to retinal oxime and opsin. The rhodopsin of Meganyctiphanes norvegica measured in fresh rhabdoms by microspectrophotometry has properties very similar to those of the extracted rhodopsin of E. superba. Its lambda max is 488 nm and it is partially photoconverted by short wavelength irradiation to a stable photoconvertible metarhodopsin similar to that of E. superba. In the presence of light and NH2OH, the M. norvegica metarhodopsin is converted to retinal oxime and opsin. Our results indicate that previous determinations of euphausiid rhodopsin absorbance spectra were incorrect because of accessory pigment contamination.

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