scholarly journals Protein Engineering of Dual-Cys Cyanobacteriochrome AM1_1186g2 for Biliverdin Incorporation and Far-Red/Blue Reversible Photoconversion

2019 ◽  
Vol 20 (12) ◽  
pp. 2935
Author(s):  
Yuto Kuwasaki ◽  
Keita Miyake ◽  
Keiji Fushimi ◽  
Yuka Takeda ◽  
Yoshibumi Ueda ◽  
...  
Keyword(s):  
Protein Engineering ◽  
Visible Light ◽  
Near Infrared ◽  
The Other ◽  
Infrared Light ◽  
Biological Research ◽  
Light Sources ◽  
Dark State ◽  
Optical Tools ◽  
Tetrapyrrole Chromophores

Cyanobacteria have cyanobacteriochromes (CBCRs), which are photoreceptors that bind to a linear tetrapyrrole chromophore and sense UV-to-visible light. A recent study revealed that the dual-Cys CBCR AM1_1186g2 covalently attaches to phycocyanobilin and exhibits unique photoconversion between a Pr form (red-absorbing dark state, λmax = 641 nm) and Pb form (blue-absorbing photoproduct, λmax = 416 nm). This wavelength separation is larger than those of the other CBCRs, which is advantageous for optical tools. Nowadays, bioimaging and optogenetics technologies are powerful tools for biological research. In particular, the utilization of far-red and near-infrared light sources is required for noninvasive applications to mammals because of their high potential to penetrate into deep tissues. Biliverdin (BV) is an intrinsic chromophore and absorbs the longest wavelength among natural linear tetrapyrrole chromophores. Although the BV-binding photoreceptors are promising platforms for developing optical tools, AM1_1186g2 cannot efficiently attach BV. Herein, by rationally introducing several replacements, we developed a BV-binding AM1_1186g2 variant, KCAP_QV, that exhibited reversible photoconversion between a Pfr form (far-red-absorbing dark state, λmax = 691 nm) and Pb form (λmax = 398 nm). This wavelength separation reached 293 nm, which is the largest among the known phytochrome and CBCR photoreceptors. In conclusion, the KCAP_QV molecule developed in this study can offer an alternative platform for the development of unique optical tools.

scholarly journals IMAGING DIAGNOSTICS OF COMBUSTION INSTABILITY IN PREMIXED SWIRLING COMBUSTION

2020 ◽  
Vol 4 ◽  
pp. 80-93
Author(s):  
Yao Yang ◽  
Gaofeng Wang ◽  
Yuanqi Fang ◽  
YIfan Xia ◽  
Liang Zhong
Keyword(s):  
Visible Light ◽  
Near Infrared ◽  
Combustion Instability ◽  
Infrared Light ◽  
Imaging Method ◽  
Near Infrared Light ◽  
Stable Combustion ◽  
Significant Difference ◽  
Unstable Combustion ◽  
Swirling Flames

An experimental study on combustion instability is presented with focus on propane-air premixed swirling flames. Swirling flames under self-excited oscillation are studied by imaging of visible light and OH* chemiluminescence filter under several typical conditions. The dynamical characteristics of swirling flames were analysed by Dynamic Mode Decomposition (DMD) method. Three types of unstable modes in the combustor system were observed, which correspond to typical acoustic resonant modes (LF mode, C1/4 mode and P1/2 mode) of the combustor system. The combustion instability is in the longitudinal mode. Furthermore, the structure of downstream hot burnt gas under stable combustion and unstable combustion is studied by imaging of visible light and near-infrared light. Results show that there is a significant difference in the downstream flow under stable combustion and unstable combustion. The DMD spectrum of the flame and the downstream hot burnt gas obtained is the same, which is close to the characteristic frequency of acoustic pressure captured by the microphone signal. The visible light and near-infrared light imaging observation method adopted in this paper provides a new imaging method for the investigation of thermo-acoustic instability.

scholarly journals Microscale optoelectronic infrared-to-visible upconversion devices and their use as injectable light sources

2018 ◽  
Vol 115 (26) ◽  
pp. 6632-6637 ◽  
Author(s):  
He Ding ◽  
Lihui Lu ◽  
Zhao Shi ◽  
Dan Wang ◽  
Lizhu Li ◽  
...  
Keyword(s):  
Near Infrared ◽  
Biological Fluids ◽  
Visible Spectral Range ◽  
Infrared Light ◽  
Light Sources ◽  
Fully Integrated ◽  
Broadband Absorption ◽  
In Vivo Experiments

Optical upconversion that converts infrared light into visible light is of significant interest for broad applications in biomedicine, imaging, and displays. Conventional upconversion materials rely on nonlinear light-matter interactions, exhibit incidence-dependent efficiencies, and require high-power excitation. We report an infrared-to-visible upconversion strategy based on fully integrated microscale optoelectronic devices. These thin-film, ultraminiaturized devices realize near-infrared (∼810 nm) to visible [630 nm (red) or 590 nm (yellow)] upconversion that is linearly dependent on incoherent, low-power excitation, with a quantum yield of ∼1.5%. Additional features of this upconversion design include broadband absorption, wide-emission spectral tunability, and fast dynamics. Encapsulated, freestanding devices are transferred onto heterogeneous substrates and show desirable biocompatibilities within biological fluids and tissues. These microscale devices are implanted in behaving animals, with in vitro and in vivo experiments demonstrating their utility for optogenetic neuromodulation. This approach provides a versatile route to achieve upconversion throughout the entire visible spectral range at lower power and higher efficiency than has previously been possible.

Analysis of relation between skin elasticity and the entropy of skin image using near‐infrared and visible light sources

2019 ◽  
Vol 13 (1) ◽  
Author(s):  
Geunho Jung ◽  
Min Young Lee ◽  
Sungchul Kim ◽  
Jee‐Bum Lee ◽  
Jae G. Kim
Keyword(s):  
Visible Light ◽  
Near Infrared ◽  
Light Sources ◽  
Skin Elasticity

Lead selenide quantum dots and carbon dots amplify solar conversion capability of a TiO2/CdS photoanode

2015 ◽  
Vol 3 (41) ◽  
pp. 20715-20726 ◽  
Author(s):  
Ramesh K. Kokal ◽  
P. Naresh Kumar ◽  
Melepurath Deepa ◽  
Avanish Kumar Srivastava
Keyword(s):  
Quantum Dots ◽  
Visible Light ◽  
Power Conversion Efficiency ◽  
Carbon Dots ◽  
Near Infrared ◽  
Power Conversion ◽  
Integrated Approach ◽  
Infrared Light ◽  
Cds Quantum Dots ◽  
Solar Conversion

An integrated approach involving the use of visible light absorbing CdS quantum dots (QDs) and near infrared light harvesting PbSe QDs, along with highly conducting carbon dots (C-dots), resulting in impressive power conversion efficiency (PCE) is presented.

scholarly journals Computational Laser Spectroscopy in a Biological Tissue

2010 ◽  
Vol 2010 ◽  
pp. 1-9 ◽  
Author(s):  
M. Gantri ◽  
H. Trabelsi ◽  
E. Sediki ◽  
R. Ben Salah
Keyword(s):  
Biological Tissue ◽  
Near Infrared ◽  
Continuous Wave ◽  
Light Transmission ◽  
Short Pulse ◽  
Control Volume ◽  
External Source ◽  
Time Dependent ◽  
Infrared Light ◽  
Light Sources

We present a numerical spectroscopic study of visible and infrared laser radiation in a biological tissue. We derive a solution of a general two-dimensional time dependent radiative transfer equation in a tissue-like medium. The used model is suitable for many situations especially when the external source is time-dependent or continuous. We use a control volume-discrete ordinate method associated with an implicit three-level second-order time differencing scheme. We consider a very thin rectangular biological-tissue-like medium submitted to a visible or a near infrared light sources. The RTE is solved for a set of different wavelength source. All sources are assumed to be monochromatic and collimated. The energetic fluence rate is computed at a set of detector points on the boundaries. According to the source type, we investigate either the steady-state or transient response of the medium. The used model is validated in the case of a heterogeneous tissue-like medium using referencing experimental results from the literature. Also, the developed model is used to study changes on transmitted light in a rat-liver tissue-like medium. Optical properties depend on the source wavelength and they are taken from the literature. In particular, light-transmission in the medium is studied for continuous wave and for short pulse.

Biomimetics in Energy Systems: Light Transmission in the Window Plant Fenestraria aurantiaca as Inspiration for New Solutions in the Technical World

2012 ◽  
Vol 84 ◽  
pp. 51-56 ◽  
Author(s):  
Immanuel Schäfer
Keyword(s):  
Solar Cells ◽  
Visible Light ◽  
Mobile Devices ◽  
Near Infrared ◽  
Light Transmission ◽  
Energy Systems ◽  
Surface Cleaning ◽  
Infrared Light ◽  
Direct Sunlight ◽  
Light Concentration

Fenestraria aurantiaca (also known as window plant) is a succulent with specialized adaptations to deal with heat, light and aridity. Fenestraria aurantiaca (F. a.) grows with most of its body under the sand. Just the top, with a light transparent surface – the window – on it, protrudes from the surface hence giving explanation to the plants name. Experiments with light, and detailed microscopy studies show the physical, biological and chemical capabilities of F. a. It was found that the window works as a lens, light from a 90 ° angle is directed into the plant. Thereby the window filters the light. Up to 90 % of the visible light is blocked; with rising wavelength the window gets more transparent until the near infrared light (1000 nm) where the transparency declines rapidly. But the parenchyma is up 90 % transparent. Based on those results the principles of the plant were defined, which are used for abstractions. Generally F.a. has four principles: light handling, surface cleaning, heat avoidance and water storing. Improvements founded on the inspiration of the window plant seem to be possible in photovoltaic systems, which have problems with overheating and also light concentration. An example solution called “buried solar cells” is presented. Another working field is the screen of mobile devices, where the clarity and readability suffers from direct sunlight. With the help from the methods displayed by F.a., there is an energy saving solution explained.

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