THE EFFECT OF FLASHING LIGHT SUPPLEMENTED BY CONTINUOUS RED AND FAR-RED LIGHT ON THE GROWTH OF LEMNA MINOR L. IN THE PRESENCE OF GROWTH REGULATORS

1964 ◽  
Vol 42 (1) ◽  
pp. 57-64 ◽  
Author(s):  
S. E. Chua ◽  
M. H. Dickson
Keyword(s):  
Growth Rate ◽  
Growth Regulators ◽  
Photosynthetic Rate ◽  
Lemna Minor ◽  
Light Exposure ◽  
Red Light ◽  
Light Period ◽  
Continuous Illumination ◽  
Low Intensity ◽  
Flashing Light

The growth rates of Lemna minor were studied under conditions of flashing light of varied durations interacted with continuous illumination of low-intensity far-red and red light, and growth regulators (0.645 p.p.m. kinetin, and 25 p.p.m. IAA). It was found that the growth rate was progressively reduced with decreasing light exposure from continuous illumination to alternating periods of 1-minute intermittency, after which it increased rapidly. The growth rate per unit of light was the most rapid at 0.01-second light period under 1:3 ratio of light to dark. Under 1:1 ratio of light to dark interacted with red and far-red light, kinetin, and IAA, the photosynthetic rate of Lemna was reduced by far-red but improved by the red light. Kinetin increased the growth rate but IAA inhibited the photosynthetic rate as the number of flashes increased. The IKI test showed that under flashing light old and young fronds stored starch but under continuous illumination, only the older fronds stored starch.

scholarly journals Influence of low-intensity radiation of the optical range spectrum (λ = 630-660 nm) on the immunoresistance parameters in animals with experimental peritonitis

2020 ◽  
Vol 82 (3) ◽  
pp. 35-41
Author(s):  
O. Klimova ◽  
A. Korobov ◽  
K. Bichenko ◽  
O. Lavinska ◽  
T. Kordon ◽  
...  
Keyword(s):  
Immune Complexes ◽  
Inflammatory Process ◽  
Light Exposure ◽  
Red Light ◽  
Intraperitoneal Administration ◽  
Circulating Immune Complexes ◽  
Physical Factors ◽  
Phagocytic Cells ◽  
Inflammatory Reactions ◽  
Low Intensity

Treatment of inflammatory and septic conditions is a serious problem due to the existing antibiotic resistance. It is necessary to find new treatments using biological and physical factors that affect the course of inflammatory reactions in chronic processes. It is important to understand the mechanisms of interaction of light photons with cellular acceptors, which provide reactivity and resistance. The aim – is to evaluate the low-intensity light effect of the red range spectrum (λ =630-660 nm) on the course of the inflammatory process in experimental animals with LPS-induced peritonitis. Animals were divided into 3 groups: A – intact animals; B – animals with peritonitis induced by intraperitoneal administration of LPS; C – animals with LPS-induced peritonitis after repeated exposure to red light. Irradiation of the abdominal wall was performed with LED matrices Korobov A. – Korobov V. "Barva-Flex/24FM", which emit in the red region of the spectrum. Methods of light microscopy (study of the barrier function in oxygen-independent phagocytosis of neutrophils, estimation of the lymphocytotoxicity degree in the Terasaki test) and spectrophotometry (determination of the concentration of circulating immune complexes) were used. In animals after induction of peritonitis (group B) was observed inhibition of phagocytosis, which manifested itself in reduced adhesion and endocytosis of antigens by neutrophils compared with intact animals. The use of light exposure of the red range spectrum (group C) significantly activated phagocytic cells and reduced the degree of lymphocytotoxicity and the concentration of circulating immune complexes at different stages of the inflammatory process. Thus, the action of red light contributed to the normalization of immunoresistance in animals, thereby reducing antigenic load by activating infiltration and exudation stages of the inflammatory process and induction of regenerative processes after repeated irradiation at the end of the experiment.

Metastable defects by low-intensity pulsed illumination of hydrogenated amorphous silicon

2000 ◽  
Vol 609 ◽  
Author(s):  
Stephan Heck ◽  
Howard M. Branz
Keyword(s):  
Amorphous Silicon ◽  
Exposure Time ◽  
Red Light ◽  
Hydrogenated Amorphous Silicon ◽  
Continuous Illumination ◽  
Defect Region ◽  
Absorption Increase ◽  
Low Intensity ◽  
Careful Measurement ◽  
Hydrogenated Amorphous

ABSTRACTIllumination of hydrogenated amorphous silicon (a-Si:H) samples with short (e.g., 40 microsecond) pulses of red light produces a smaller metastable absorption increase in the defect region than continuous illumination of the same intensity for the same integrated exposure time. The defect absorption was measured at 1.3 and 1.4 eV by use of the constant photocurrent method (CPM). This smaller degradation is also observed in the photoconductivity. Careful measurement of the film temperature with several techniques confirm that the film temperature rises by less than 5 °C, under continuous illumination. However, several experiments suggest that the suppressed degradation during pulsed illumination is caused primarily by annealing during the dark time between pulses, even at 15 to 26 °C.

MECHANISMS OF IMMUNOCORRECTIVE ACTION OF PHOTODYNAMIC THERAPY AND EXOSOMES OF MESENCHYMAL STEM CELLS IN PATIENTS WITH CHRONIC WOUNDS OF THE LOWER EXTREMITIES OF DIFFERENT GENESIS

2021 ◽  
pp. 20-27
Author(s):  
O. M. Klimova ◽  
Yu. V. Ivanova ◽  
K. A. Bychenko ◽  
O. S. Merezhko ◽  
V. O. Prasol ◽  
...  
Keyword(s):  
Photodynamic Therapy ◽  
Growth Factor ◽  
Chronic Wounds ◽  
Light Exposure ◽  
Red Light ◽  
Lower Extremities ◽  
Light Therapy ◽  
Vascular Growth ◽  
Low Intensity ◽  
Vascular Growth Factor

Summary. Introduction. The treaonic wounds of the lower extremities today requires long-term use of antibiotic therapy, which aggravates the course of the wound process. In this regard, the search for new methods of treatment is underway. Low-intensity light exposure of various wavelengths of photodynamic therapy with photosensitizer photosensitizer Dimegin was used as a physical method, and multipotent mesenchymal-stromal cells and their exometabolites in exosomes form were used as a biological method. The aim was to study the change of barrier function of oxygen-independent and oxygen-dependent phagocytosis and serum levels of vascular growth factor (VEGF) in patients with chronic wounds of the lower extremities before and after the application of complex light exposure and exosomes. Materials and methods. Phagocytosis activity of neutrophils was investigated by assessing chemotaxis, adhesion and endocytosis and by determining reactive oxygen species (ROS) in oxygen-dependent phagocytosis using light and confocal microscopy. VEGF concentration was determined by ELISA. Results: after photodynamic therapy using with red light (λ=660nm), activation of oxygen-independent and oxygen-dependent phagocytosis was observed, as well as an increase in the synthesis of vascular growth factor in patients with chronic wounds of the lower extremities. After the application of green light (λ=530nm) and the application of exosomes, the normalization of immune processes was observed, which led to the acceleration of regenerative processes in the wound. Conclusions. Thus, after carrying out complex low-intensity light therapy and exosomes, it was possible to completely clear the wounds from necrosis in a short time.

scholarly journals Artificial complementary chromatic acclimation gene expression system in Escherichia coli

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Dwi Ariyanti ◽  
Kazunori Ikebukuro ◽  
Koji Sode
Keyword(s):  
Gene Expression ◽  
Escherichia Coli ◽  
Light Exposure ◽  
Expression System ◽  
Red Light ◽  
Green Light ◽  
Light Illumination ◽  
Multiple Gene ◽  
Gene Expression System ◽  
Chromatic Acclimation

Abstract Background The development of multiple gene expression systems, especially those based on the physical signals, such as multiple color light irradiations, is challenging. Complementary chromatic acclimation (CCA), a photoreversible process that facilitates the control of cellular expression using light of different wavelengths in cyanobacteria, is one example. In this study, an artificial CCA systems, inspired by type III CCA light-regulated gene expression, was designed by employing a single photosensor system, the CcaS/CcaR green light gene expression system derived from Synechocystis sp. PCC6803, combined with G-box (the regulator recognized by activated CcaR), the cognate cpcG2 promoter, and the constitutively transcribed promoter, the PtrcΔLacO promoter. Results One G-box was inserted upstream of the cpcG2 promoter and a reporter gene, the rfp gene (green light-induced gene expression), and the other G-box was inserted between the PtrcΔLacO promoter and a reporter gene, the bfp gene (red light-induced gene expression). The Escherichia coli transformants with plasmid-encoded genes were evaluated at the transcriptional and translational levels under red or green light illumination. Under green light illumination, the transcription and translation of the rfp gene were observed, whereas the expression of the bfp gene was repressed. Under red light illumination, the transcription and translation of the bfp gene were observed, whereas the expression of the rfp gene was repressed. During the red and green light exposure cycles at every 6 h, BFP expression increased under red light exposure while RFP expression was repressed, and RFP expression increased under green light exposure while BFP expression was repressed. Conclusion An artificial CCA system was developed to realize a multiple gene expression system, which was regulated by two colors, red and green lights, using a single photosensor system, the CcaS/CcaR system derived from Synechocystis sp. PCC6803, in E. coli. The artificial CCA system functioned repeatedly during red and green light exposure cycles. These results demonstrate the potential application of this CCA gene expression system for the production of multiple metabolites in a variety of microorganisms, such as cyanobacteria.

Use of A GAS Jet Technique to Prepare Microcrystalline Silicon Based Solar Cells at High I-Layer Deposition Rates

1999 ◽  
Vol 557 ◽  
Author(s):  
S.J. Jones ◽  
R. Crucet ◽  
X. Deng ◽  
J. Doehler ◽  
R. Kopf ◽  
...  
Keyword(s):  
Solar Cells ◽  
Peak Power ◽  
Light Exposure ◽  
Red Light ◽  
Gas Jet ◽  
Scale Production ◽  
Microcrystalline Silicon ◽  
Deposition Rates ◽  
Layer Deposition ◽  
Power Outputs

AbstractUsing a Gas Jet thin film deposition technique, microcrystalline silicon (μc-Si) materials were prepared at rates as high as 15-20 Å/s. The technique involves the use of a gas jet flow that is subjected to a high intensity microwave source. The quality of the material has been optimized through the variation of a number of deposition conditions including the substrate temperature, the gas flows, and the applied microwave power. The best films were made using deposition rates near 16 Å/s. These materials have been used as i-layers for red light absorbing, nip single-junction solar cells. Using a 610nm cutoff filter which only allows red light to strike the device, pre-light soaked currents as high as 10 mA/cm2 and 2.2-2.3% red-light pre-light soaked peak power outputs have been obtained for cells with i-layer thicknesses near 1 micron. This compares with currents of 10-11 mA/cm2 and 4% initial red-light peak power outputs obtained for high efficiency amorphous silicon germanium alloy (a-SiGe:H) devices. The AM1.5 white light efficiencies for these microcrystalline cells are 5.9-6.0%. While the efficiencies for the a-SiGe:H cells degrade by 15-20% after long term light exposure, the efficiencies for the microcrystalline cells before and after prolonged light exposure are similar, within measurement error. Considering these results, the Gas Jet deposition method is a promising technique for the deposition of μc-Si solar cells due to the ability to achieve reasonable stable efficiencies for cells at i-layer deposition rates (16 Å/s) which make large-scale production economically feasible.

The influence of red and blue light on the rate of photosynthesis and the CO2 compensation point at various oxygen concentrations

1970 ◽  
Vol 48 (6) ◽  
pp. 1251-1257 ◽  
Author(s):  
N. P. Voskresenskaya ◽  
G. S. Grishina ◽  
S. N. Chmora ◽  
N. M. Poyarkova
Keyword(s):  
Nicotiana Tabacum ◽  
Blue Light ◽  
Photosynthetic Rate ◽  
Prolonged Exposure ◽  
Red Light ◽  
Compensation Point ◽  
Gas Analyzer ◽  
Co2 Compensation Point ◽  
Rate Of Photosynthesis ◽  
Light Inhibition

Apparent photosynthesis of attached leaves of Phaseolus vulgaris, Vicia faba, Pisum sativum, and Nicotiana tabacum at various intensities of blue and red light was measured by infrared CO2 gas analyzer in a closed system. Simultaneously the CO2 compensation point was measured.It was found that light-limited photosynthetic rate in blue light was equal to or more than that in red light. Inhibition of photosynthesis, which sometimes occurred at light-saturated intensities of blue light, could be avoided by addition of red light, prolonged exposure of the plants to blue light, or by lowering the O2 concentration. Accordingly, the increase of photosynthetic rate due to change of O2 concentration from 21 to 3% O2 is higher in blue light only when photosynthesis is inhibited by blue light at 21% O2. The data on the action of blue and red light on the CO2 compensation point seems to exclude the activation of photorespiration by blue light.The possible effects of blue light on apparent photosynthesis are discussed on the basis of the results presented.

scholarly journals Effects of Low Intensity Red Light on Testicular Recrudescence in Japanese Quail

1981 ◽  
Vol 60 (2) ◽  
pp. 453-461 ◽  
Author(s):  
R.P. GILDERSLEEVE ◽  
W.A. JOHNSON
Keyword(s):  
Japanese Quail ◽  
Red Light ◽  
Low Intensity ◽  
Testicular Recrudescence

LIGHT AND TEMPERATURE EFFECTS ON GROWTH AND SPOROPHORE FORMATION OF LENZITES TRABEA

1967 ◽  
Vol 45 (4) ◽  
pp. 525-530
Author(s):  
C. Madhosingh
Keyword(s):  
Temperature Effects ◽  
Growth Form ◽  
Red Light ◽  
Vegetative Mycelium ◽  
Temperature Growth ◽  
Low Intensity ◽  
Morphological Studies ◽  
Brown Pigmentation ◽  
Yellow Pigments ◽  
Red Radiation

Growth, pigmentation, and sporophore formation in Lenzites trabea, a polypore fungus, are shown to be affected by differences in light and temperature. Growth occurred under all conditions provided, being greater on liquid substrate than on agar and with maximum mycelium production in continuous red light at 25 °C. Sporophores, however, were formed only under certain continuous fluorescent and red radiations on liquid substrate; and on agar at 15 °C, 20 °C, and 25 °C in darkness broken by occasional brief exposures to low intensity daylight. The growth form under the red radiation and in darkness at 25 °C was similar. The form of fructification varied from poroid resupinate at 15 °C, to somewhat raised structures with larger pores at 20 °C, to an assemblage of discrete upright bodies with lacerated surface at 25 °C. Yellow-brown pigmentation was consistently associated with the fruiting areas in contrast with the predominantly fawn-yellow pigments of the vegetative mycelium. The significance of these results in comparative morphological studies is discussed.

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