Intense Blue Light Research Articles

In Vitro Testing of Protective Eye Wear in Blocking Blue Light from Dental Light Curing Unit

Aim: To evaluate the ef?cacy of wearing protective eyewear in preventing harmful Dental light-curing units (LCUs). Background: Dental light-curing units generate blue light, capable of inducing soft-tissue burns and ocular harm like retinal damage. The intensity of blue light emitted by dental Light Curing Units is substantially higher, thereby potentially constituting a significant "blue light hazard." Material and Methods: To study the effect of protective glasses, reverse methodology was followed as the effect of blue light on the eye is difficult to measure; Circular composite disc samples were grouped into two, one of which was polymerized directly while the other had protective glass in between, Fourier transform infrared spectroscopy (FTIR) analysis was done and the degree of conversion was calculated. Results: Data obtained were analysed using One Way ANOVA. The mean values for "Degree of Conversion" in Group I (Without Protective Glass) is 1.334 +512 and for Group II (with protective glass) is -2.623 + 1.544 .One Way ANOVA revealed statistically significant difference between Group I and Group II (p=0.000) Conclusion: Within the limitations of this in vitro study, it can be concluded that the protective glasses are successful in filtering the harmful blue light emitted by LCU and should be used in day-to-day practice to improve the amount of light they deliver to the restoration from the LCU and prevent any harm to the ocular tissues. Clinical implications: Blue light filtering glasses in a dental operatory provide optimum protection, and the operator can safely watch and improve the amount of light delivered to the restoration from the LCU.

Preparation of Imidazole Compounds as Latent Curing Agents and Their Application in RGB LED Packaging.

LED packaging miniaturization has raised more requirements for LED materials. As a material contacting the LED chip directly, the reliability of LED non-conductive adhesive has also garnered increasing attention. This study optimized the formula for non-conductive adhesives for an imidazole curing system. The optimized composition of the adhesive is 25%wt for the curing agent and 30%wt for the silica. The prepared non-conductive adhesive has a 7-day pot life and 9-month storage stability. The shear strength reached 87 g and 72 g at 25 °C and 160 °C, respectively. The reliability of the LED modules packaged with the non-conductive adhesive was researched. The green and blue light intensity change was 4.7%, 43.7%, respectively, indicating good anti-aging properties. The blue light decay was mainly due to adhesive aging. The non-conductive adhesive effectively prevented "caterpillar" growth. This provides useful and practical guidelines for industry for applications of adhesive in different packages.

Response of blue light in different proportions on the growth & flowering in sunflower

Due to the light sensitivity of sunflowers, regulating spectral composition holds significant potential for optimizing sunflower growth and flowering to meet market demands. In this study, sunflower plants were exposed to white light (W200, control) and three levels of blue light (B40R80Fr80 with blue light intensity of 40 µmol m−2 s−1; B67R67Fr67 with blue light intensity of 67 µmol m−2 s−1; B100R50Fr50 with blue light intensity of 100 µmol m−2 s−1) under an overall irradiance level of 200 µmol m−2 s−1 for 60 days. The aim was to investigate the effects on sunflower morphology regulation, leaf growth, and flowering. Results demonstrated that the growth of sunflowers under B40R80Fr80 treatment with 20 % blue light inhibited plant height compared with B67R67Fr67 and B100R50Fr50 treatments. The highest total leaf dry weight was observed in sunflower leaves under the B100R50Fr50 treatment. Leaves under B67R67Fr67 treatment enhanced activities of Glyceraldehyde 3-phosphate dehydrogenase, Fructose-1,6-bisphosphate aldolase, and soluble starch synthase, along with a 10.4 % increase in Rubisco activity compared with B100R50Fr50 treatment. The sucrose and starch content under B67R67Fr67 treatment increased by 41.0 % and 19.1 % than those of B100R50Fr50 treatment, respectively. Sunflower plants under B67R67Fr67 treatment significantly improved flower disk diameter and No. of petal per flower compared with W200 treatment. Phenotype-assisted transcriptome analysis revealed that B67R67Fr67 treatment on sunflower leaves had positive effects on circadian rhythm-related genes associated with flowering [CONSTITUTIVELY PHOTOMORPHOGENIC 1 (COP1) and FLOWERING LOCUS T (FT)], compared with B100R50Fr50 treatment. Additionally, four genes related to GA metabolism were identified for flower development regulation; LOC110884159 and LOC110890361 (GID1B) were up-regulated under B67R67Fr67 treatment. Sunflower leaves under B67R67Fr67 treatment increased GA content and induced the GA pathway related to circadian rhythm, compared with those of B100R50Fr50 treatment. Consequently, the implementation of B67R67Fr67 treatment led to improved circadian rhythm and GA pathway activation, resulting in induced flowering to fulfill market demands for sunflowers.

Solid-state reaction synthesis of LuPO4:Yb3+, Tb3+ phosphors and the ultraviolet/near-infrared responsive spectra performances

Yb3+/Tb3+ co-doped LuPO4 phosphors were prepared by solid-state reaction method. The effects of Yb3+/Tb3+ doping concentrations on the downshifting and upconversion spectral performances of the synthesized phosphors were investigated. Upon the ultraviolet light excitation, the phosphors show obvious visible light emission, which can be assigned to the 5D4→7FJ (J=6, 5, 4, and 3) transitions of Tb3+ ions respectively, the green light emission at 543 nm is dominant. Upon 980 nm excitation, the phosphors display intense green and blue light emission, and weak yellow and red light emission, which originates from the cooperative energy transfer process between Yb3+ and Tb3+ ions. The synthesized LuPO4:Yb3+, Tb3+ phosphors show good ultraviolet/near-infrared responsive spectra, color-tunable and thermal-stability performances and may have potential applications in the related fields.

A single phased full color emitting pyrochlore type phosphor La2Y0.66Sn0.66Sb0.66O7: Bi3+, Eu3+ for white light emitting diode applications (WLEDs)

The phosphor converted white light emitting diodes (pc-WLEDs) are advancing rapidly in replacing the conventional fluorescent and incandescent light sources. However, the current technology of pc-WLEDs limits their large scale indoor lighting applications due to their high correlated color temperature (CCT) and poor color rendering index (CRI). In this work, a single phased full color emitting phosphor in the pyrochlore oxide system, La2Y0.66Sn0.66Sb0.66O7: Bi3+, Eu3+ has been developed by the high temperature ceramic route. The developed phosphors are characterized by powder X-ray diffraction, luminescence and lifetime measurements. Upon near UV excitation wavelength, the singly doped phosphor, La2Y0.66Sn0.66Sb0.66O7: Bi3+ show intense blue green light in the wavelength region 400–600 nm due to the characteristic transitions (3P1 → 1S0) of Bi3+. The emission spectral analysis suggests that there exist two luminescence centers of Bi3+ due to occupation of different crystallographic sites in the pyrochlore lattice of La2Y0.66Sn0.66Sb0.66O7. The deficit of red component in the emission spectra is overcome by the Eu3+ co-doping in the system, La2Y0.66Sn0.66Sb0.66O7: Bi3+, Eu3+ which results in the full color emission covering the visible spectral range up to 700 nm with broad peaks along with sharp narrow characteristic peaks of Eu3+. The full color emission of the La2Y0.66Sn0.66Sb0.66O7: 0.04Bi3+, yEu3+ phosphors can be tuned by adjusting the suitable Eu3+ dopant concentration and using appropriate energy transfer from Bi3+ to Eu3+. The full color emitting phosphor, La2Y0.66Sn0.66Sb0.66O7:0.04Bi3+, 0.06Eu3+ can be realized with the color coordinates (0.30, 0.36), and correlated color temperature (4383K). All these results demonstrate that La2Y0.66Sn0.66Sb0.66O7:xBi3+, yEu3+ are potential single phased full color emitting phosphors for the development of pc-WLEDs.

Oxidative and carbonyl stress induced AMD and Codonopsis lanceolata ameliorates AMD via controlling oxidative and carbonyl stress

Age-related macular degeneration (AMD) is one of the leading causes of blindness. AMD is currently incurable; the best solution is to prevent its occurrence. To develop drugs for AMD, it is crucial to have a model system that mimics the symptoms and mechanisms in patients. It is most important to develop safer and more effective anti-AMD drug. In this study, the dose of A2E and the intensity of blue light were evaluated to establish an appropriate atrophic in vitro model of AMD and anti-AMD effect and therapeutic mechanism of Codonopsis lanceolata. The experimental groups included a control group an AMD group treated with A2E and blue light, a lutein group treated with 25 μM lutein after AMD induction, and three groups treated with different doses of C. lanceolata (10, 20, and 50 μg/mL) after AMD induction. Intrinsic apoptotic pathway (Bcl-2 family), anti-oxidative system (Keap1/Nrf2/HO-1 antioxidant response element), and anti-carbonyl effect (4-hydroxynonenal [4-HNE]) were evaluated using immunofluorescence, MTT, TUNEL, FACS, and western blotting analyses. A2E accumulation in the cytoplasm of ARPE-19 cells depending on the dose of A2E. Cell viability of ARPE-19 cells according to the dose of A2E and/or blue light intensity. The population of apoptotic or necrotic cells increased based on the A2E dose and blue light intensity. Codonopsis lanceolata dose-dependently prevented cell death which was induced by A2E and blue light. The antiapoptotic effect of that was caused by activating Keap1/Nrf2/HO-1 pathway, suppressing 4-HNE, and modulating Bcl-2 family proteins like increase of antiapoptotic proteins such as Bcl-2 and Bcl-XL and decrease of proapoptotic protein such as Bim. Based on these findings, 30 μM A2E and 20 mW/cm2 blue light on adult retinal pigment epithelium-19 cells was an appropriate condition for AMD model and C. lanceolata shows promise as an anti-AMD agent.

The influence of prolonged but low intensity blue light on the physiological properties of root tubers and the accumulation of flavonoids in Tetrastigma hemsleyanum Diels et Gilg

Tetrastigma hemsleyanum Diel et Gilg is a perennial herbaceous plant native to subtropical China with multiple medicinal applications. Supplementing with low-density blue light (BL) for 45 days (3 h/day) can not only significantly increase the yields of root tubers but also significantly increase the flavonoid content and its antioxidant activity. The chlorophyll content in the leaves of T. hemsleyanum significantly decreased, but the photosynthetic efficiency significantly increased after reaching the light saturation point. The production rate of superoxide anion radical in the leaves reached the highest peak after 1.5 h in BL and decreased at 3 h. The H2O2 content in the leaves decreased significantly, while the H2O2 content in the root tubers increased significantly at 3 h in BL. The objective of this research was to determine how the scavenging system, including antioxidant enzymes, antioxidants, and flavonoids respond to the oxidative stress induced by BL in root tubers. After exposure to BL, significant differences in the activity of APX and SOD were observed in the leaves and tubers within 3 h. By analyzing the upregulated flavonoids metabolites and key genes in metabolic pathways through the combined analysis of the flavonoid metabolic group and transcriptome in the root tubers, the upregulated accumulation of flavanols was found to be the main reason for the improvement in the antioxidant properties of flavonoids.

TRANSPARENT TESTA GLABRA1 Regulates High-Intensity Blue Light-Induced Phototropism by Reducing CRYPTOCHROME1 Levels.

The asymmetrical distribution of auxin supports high intensity blue light (HBL)-mediated phototropism. Flavonoids, secondary metabolites induced by blue light and TRANSPARENT TESTA GLABRA1 (TTG1), alter auxin transport. However, the role of TTG1 in HBL-induced phototropism in Arabidopsis (Arabidopsis thaliana) remains unclear. We found that TTG1 regulates HBL-mediated phototropism. HBL-induced degradation of CRYPTOCHROME 1 (CRY1) was repressed in ttg1-1, and depletion of CRY1 rescued the phototropic defects of the ttg1-1 mutant. Moreover, overexpression of CRY1 in a cry1 mutant background led to phototropic defects in response to HBL. These results indicated that CRY1 is involved in the regulation of TTG1-mediated phototropism in response to HBL. Further investigation showed that TTG1 physically interacts with CRY1 via its N-terminus and that the added TTG1 promotes the dimerization of CRY1. The interaction between TTG1 and CRY1 may promote HBL-mediated degradation of CRY1. TTG1 also physically interacted with blue light inhibitor of cryptochrome 1 (BIC1) and Light-Response Bric-a-Brack/Tramtrack/Broad 2 (LRB2), and these interactions either inhibited or promoted their interaction with CRY1. Exogenous gibberellins (GA) and auxins, two key plant hormones that crosstalk with CRY1, may confer the recovery of phototropic defects in the ttg1-1 mutant and CRY1-overexpressing plants. Our results revealed that TTG1 participates in the regulation of HBL-induced phototropism by modulating CRY1 levels, which are coordinated with GA or IAA signaling.

Diverse Flowering Response to Blue Light Manipulation: Application of Electric Lighting in Controlled-Environment Plant Production

Blue light is an important light wavelength in regulating plant flowering. In a controlled environment (CE) plant production systems, blue light can be manipulated easily and even precisely through electric lighting, especially with the advancement of light-emitted diode (LED) technologies. However, the results of previous studies in the literature about blue-light-mediated flowering are inconsistent, which would limit its practical application in CE plant production while implying that an in-depth study of the relevant physiological mechanism is necessary in the future. This review consolidates and analyzes the diverse findings from previous studies on blue light-mediated plant flowering in varying high-value crops from ornamental plants to fruits, vegetables, and specialty crops. By synthesizing the contrasting results, we proposed the possible explanations and even the underlying mechanisms related to blue light intensity and exposure duration, its co-action with other light wavelengths, background environment conditions, and the involved photoreceptors. We have also identified the knowledge gaps based on these studies and outlined future directions for research and potential application in this promising field. This review provides valuable insights into the important and diverse role of blue light in plant flowering and offers a foundation for further investigations to optimize plant flowering through lighting technologies.

Levels of photoactivated phototropin modulate signal transmission during the chloroplast accumulation response.

Chloroplasts accumulate in regions of plant cells exposed to irradiation to maximize light reception for efficient photosynthesis. This response is mediated by the blue-light receptor phototropin. Upon the perception of blue light, phototropin is photoactivated, an unknown signal is transmitted from the photoactivated phototropin to distant chloroplasts, and the chloroplasts begin their directional movement. How activated phototropin initiates this signal transmission is unknown. Here, using the liverwort Marchantia polymorpha, we analysed whether increased photoactive phototropin levels mediate signal transmission and chloroplast behaviour during the accumulation response. The signal transmission rate was higher in transgenic cells overexpressing phototropin than in wild-type cells. However, the chloroplast directional movement was similar between wild-type and transgenic cells. Consistent with the observation, increasing the amount of photoactivated phototropin through higher blue-light intensity also accelerated signal transmission but did not affect chloroplast behaviour in wild-type cells. Photoactivation of phototropin under weak blue-light led to the greater protein level of phosphorylated phototropin in cells overexpressing phototropin than in wild-type cells, whereas the autophosphorylation level within each phototropin molecule was similar. These results indicate that the abundance of photoactivated phototropin modulates the signal transmission rate to distant chloroplasts but does not affect chloroplast behaviour during the accumulation response.

Enhanced health benefits of Psidium guajava peel fermented with Lactiplantibacillus from Myeolchi-jeot: Antioxidant, anti-inflammatory, and anti-cancer properties

Psidium guajava, commonly known as guava, is a fruit with well-documented health benefits due to its rich phytochemical content. In this study, we investigated the potential health-enhancing properties of Psidium guajava fermented with Lactiplantibacillus sp., FSA-4 isolated from salted and fermented anchovies. The fermentation condition was optimized for maximum total phenolic content (TPC) which was attained at 25 °C, at pH 7 under blue light intensity (470 nm). The pre/post fermented guava peel extracts were analyzed for their biomedical applications. The results demonstrated that the fermented guava peel extract exhibits remarkable antioxidant activity evidenced by its capacity to scavenge free radicals and reduce oxidative stress. Additionally, the fermented extract showcases potential anti-inflammatory properties, as it effectively mitigates inflammatory responses in in vitro conditions. Furthermore, the fermented guava peel extract revealed promising anti-cancer property demonstrated by its ability to inhibit the proliferation of B16–F10 cell lines by inducing apoptosis. The UPLC MS/MS analysis revealed a distinctive group of flavonols present in the fermented guava peel extract with characteristic properties. Overall, the Psidium guajava fermented extract prepared using Lactiplantibacillus sp. FSA-4 presents a multifaceted health-promoting profile, offering significant antioxidant, anti-inflammatory, and anti-cancer potential. These discoveries highlight the value of investigating traditional fermented foods and their associated microbial strains to pave the way for pioneering functional products that can have extensive applications in therapy and well-being.

Endoscopic 5-Aminolevulinic Acid–Induced Fluorescence-Guided Intraparenchymal Brain Tumor Resection—Can the Endoscope Detect More Fluorescence Than the Microscope?

ObjectivesUsing a laboratory-based optical setup we show that 5ALA fluorescence is better detected using the endoscope than the microscope. Furthermore, we present our case series of fully-endoscopic 5ALA guided resection of intraparenchymal tumors. MethodsA Zeiss Pentero® microscope was compared to the Karl Storz Hopkins® endoscope. The spectra and intensity of each blue light source were measured. Quantitative fluorescence detection thresholds were measured using a spectrometer. Subjective fluorescence detection thresholds were measured by 6 blinded neuro-oncology surgeons. Clinical data were prospectively collected for all consecutive cases of fully-endoscopic 5ALA guided resection of intraparenchymal tumors between 2012-2023. ResultsThe intensity of blue light on the sample was greater for the endoscope than the microscope at working distances below 20mm. The quantitative fluorescence detection thresholds were lower for the endoscope than the microscope at both 30/10mm working distances. Fluorescence detection threshold was 0.65-0.80% relative DCM concentration (3.20x10-7 to 3.94x10-7mol/dm-3) for the microscope, 0.40-0.55 % relative concentrations (1.97x10-7 to 2.71x10-7mol/dm-3) for the endoscope at 30mm and 0.15-0.30% relative concentrations (7.40x10-8 to 1.48x10-7mol/dm-3) for the endoscope at 10mm.49 5ALA endoscope-assisted brain tumor resections were carried out on 45 patients (mean age=41, male=28). Greater than 95% resection was achieved in 80% of cases and gross total resection (GTR) in 42%. GTR was achieved in 100% of tumors in non-eloquent locations. There was 1 new neurological deficit. ConclusionThe endoscope provides enhanced visualization/detection of 5ALA-induced fluorescence compared to the microscope. 5ALA endoscopic-assisted resection of intraparenchymal tumors is safe and feasible.

Light quality-dependent roles of REVEILLE proteins in the circadian system.

Several closely related Myb-like activator proteins are known to have partially redundant functions within the plant circadian clock, but their specific roles are not well understood. To clarify the function of the REVEILLE 4, REVEILLE 6, and REVEILLE 8 transcriptional activators, we characterized the growth and clock phenotypes of CRISPR-Cas9-generated single, double, and triple rve mutants. We found that these genes act synergistically to regulate flowering time, redundantly to regulate leaf growth, and antagonistically to regulate hypocotyl elongation. We previously reported that increasing intensities of monochromatic blue and red light have opposite effects on the period of triple rve468 mutants. Here, we further examined light quality-specific phenotypes of rve mutants and report that rve468 mutants lack the blue light-specific increase in expression of some circadian clock genes observed in wild type. To investigate the basis of these blue light-specific circadian phenotypes, we examined RVE protein abundances and degradation rates in blue and red light and found no significant differences between these conditions. We next examined genetic interactions between RVE genes and ZEITLUPE and ELONGATED HYPOCOTYL5, two factors with blue light-specific functions in the clock. We found that the RVEs interact additively with both ZEITLUPE and ELONGATED HYPOCOTYL5 to regulate circadian period, which suggests that neither of these factors are required for the blue light-specific differences that we observed. Overall, our results suggest that the RVEs have separable functions in plant growth and circadian regulation and that they are involved in blue light-specific circadian signaling via a novel mechanism.

Wavelength and Light Intensity Affect Macro- and Micronutrient Uptake, Stomata Number, and Plant Morphology of Common Bean (Phaseolus vulgaris L.)

It is already known that light quality and intensity have major influences on the growth, etiolation, germination, and morphology of many plant species, but there is limited information about the effect of wavelength and light intensity on nutrient absorption by plants. Therefore, this study was established to evaluate the plant growth, stomata formation, chlorophyll index, and absorption of macro- and micronutrients by common bean plants under six light treatments. The experimental design was completely randomized and consisted of six treatments: strong blue (blue LED at high light intensity); weak blue (blue LED at low light intensity); strong red (red LED at high light intensity); weak red (red LED at low light intensity; pink (combined red + blue LED), and white (combined red + white led). The stomatal density (stomata mm−2); the SPAD index; plant height (cm); root length (cm); plant dry weight (g); root dry weight (g); and the concentrations of N, S, K, Mg, Ca, B, Zn, Mn, and Fe on leaf analysis were influenced by all treatments. We found that plant photomorphogenesis is controlled not only by the wavelength, but also by the light intensity. Etiolation was observed in bean plants under blue light at low intensity, but when the same wavelength had more intensity, the etiolation did not happen, and the plant height was the same as plants under multichromatic lights (pink and white light). The smallest plants showed the largest roots, some of the highest chlorophyll contents, and some of the highest stomatal densities, and consequently, the highest dry weight, under white LED, showing that the multichromatic light at high intensity resulted in better conditions for the plants in carbon fixation. The effect of blue light on plant morphology is intensity-dependent. Plants under multichromatic light tend to have lower concentrations of N, K, Mg, and Cu in their leaves, but the final amount of these nutrients absorbed is higher because of the higher dry weight of these plants. Plants under blue light at high intensity tended to have lower concentrations of N, Cu, B, and Zn when compared to the same wavelength at low intensity, and their dry weight was not different from plants grown under pink light. New studies are needed to understand how and on what occasions intense blue light can replace red light in plant physiology.

Flowering and Runnering of Seasonal Strawberry under Different Photoperiods Are Affected by Intensity of Supplemental or Night-Interrupting Blue Light

The strawberry (Fragaria × ananassa Duch.) “Sulhyang” is a typical seasonal flowering (SF) strawberry that produces flower buds in day lengths shorter than a critical limit (variable, but often defined as <12 h). There is a trade-off between photoperiod-controlled flowering and gibberellin (GA) signaling pathway-mediated runnering. Some related genes (such as CO, FT1, SOC1, and TFL1) participating in light signaling and circadian rhythm in plants are altered under blue light (BL). Sugars for flowering and runnering are mainly produced by photosynthetic carbon assimilation. The intensity of light could affect photosynthesis, thereby regulating flowering and runnering. Here, we investigated the effect of the intensity of supplemental blue light (S-BL) or night-interrupting blue light (NI-BL) in photoperiodic flowering and runnering regulation by applying 4 h of S-BL or NI-BL with either 0, 10, 20, 30, or 40 μmol·m−2·s−1 photosynthetic photon flux density (PPFD) in a 10 h short-day (SD10) (SD10 + S-BL4 or + NI-BL4 (0, 10, 20, 30, or 40)) or 14 h long-day (LD14) conditions (LD14 + S-BL4 or + NI-BL4 (0, 10, 20, 30, or 40)). Approximately 45 days after the photoperiodic light treatment, generally, whether S-BL or NI-BL, BL (20) was the most promotive in runnering, leading to more runners in both the LD and SD conditions. For flowering, except the treatment LD14 + S-BL, BL (20) was still the key light, either from BL (20) or BL (40), promoting flowering, especially when BL acted as the night-interrupting light, regardless of the photoperiod. At the harvest stage, larger numbers of inflorescences and runners were observed in the LD14 + NI-BL4 treatment, and the most were observed in the LD14 + NI-BL (20). Moreover, the SD10 + NI-BL4 was slightly inferior to the LD14 + NI-BL4 in increasing the numbers of inflorescences and runners, but it caused earlier flowering. Additionally, the circadian rhythm expression of flowering-related genes was affected differently by the S-BL and NI-BL. After the application of BL in LD conditions, the expression of an LD-specific floral activator FaFT1 was stimulated, while that of a flowering suppressor FaTFL1 was inhibited, resetting the balance of expression between these two opposite flowering regulators. The SD runnering was caused by BL in non-runnering SD conditions associated with the stimulation of two key genes that regulate runner formation in the GA pathway, FaGRAS32 and FaGA20ox4. In addition, the positive effects of BL on enhancing photosynthesis and carbohydrate production also provided an abundant energy supply for the flowering and runnering processes.

Up-conversion emission of Yb3+/Tm3+-activated SrNb2O6 lead-free glass-ceramics for optical temperature sensors

The development of fluorescent materials with excellent thermal stability and high-temperature sensitivity is urgently needed to meet the rapidly growing temperature sensors. In this paper, the SrO-SrF2-Nb2O5-Al2O3-B2O3-SiO2-Yb2O3-Tm2O3 glasses were fabricated by high-temperature melting method. And the glass-ceramic with the optimal concentration of 4.0Yb3+/0.1Tm3+ was obtained after heat treatment of 800 °C for 30 min. Only the nanocrystalline SrNb2O6 crystal phase with a tetragonal structure precipitated from the glass matrix. The as-prepared glass-ceramic material produced intense blue light emission and excellent thermal cyclic stability. Utilizing the fluorescence intensity ratio technique, the glass-ceramic material showed the supreme relative sensitivity of 2.63 %K−1 at 298 K using thermally coupled energy levels (TCELs) and the highest absolute sensitivity of 22.10 %K−1 at 598 K employing non-TCELs. These findings show that Yb3+/Tm3+- doped SrNb2O6 glass-ceramic material is a promising candidate for optical sensor application.

Influence of Additional White, Red and Far-Red Light on Growth, Secondary Metabolites and Expression of Hormone Signaling Genes in Scots Pine under Sunlight.

The influence of short-term additional white (WL), red (RL) and far-red (FRL) light and combined RL+FRL on the physiological morphological and molecular characteristics of two-year-old Scots pine plants grown in a greenhouse under sunlight was studied. Additional RL and RL+FRL increased the number of xylem cells, transpiration and the expression of a group of genes responsible for the biosynthesis and signaling of auxins (AUX/IAA, ARF3/4, and ARF16) and brassinosteroids (BR-α-RED and BRZ2), while the expression of genes related to the signaling pathway related to jasmonic acid was reduced. Additionally, WL, RL and RL+FRL increased the content of proanthocyanidins and catechins in young needles; however, an increase in the expression of the chalcone synthase gene (CHS) was found under RL, especially under RL+FRL, which possibly indicates a greater influence of light intensity than observed in the spectrum. Additional WL increased photosynthetic activity, presumably by increasing the proportion and intensity of blue light; at the same time, the highest transpiration index was found under RL. The results obtained indicate that the combined effect of additional RL+FRL can accelerate the development of pine plants by increasing the number of xylem cells and increasing the number of aboveground parts but not the photosynthetic activity or the accumulation of secondary metabolites.

Transcriptional analysis reveals new insights into the different light intensities of red and blue light on the growth and synthesis of medicinal ingredients in Dendrobium denneanum

The intensity of red-blue light has important impacts on plant growth and medicinal ingredients. To identify the key genes of Dendrobium denneanum responsive to red-blue light intensity, and to reveal the regulatory mechanism of red-blue light intensity on the growth, development and medicinal quality in D. denneanum. In this experiment, D. denneanum was treated with red-blue light (2R/3B) under various light intensity (50, 100, 200, 400, 800 μmol•m−2•s−1), while the control group was white light, the photoperiod was 8/16 h (day/night). And the changes of plant growth, development, and medicinal components were studied by physiological, biochemical and transcriptome analysis. The results demonstrated that the light intensity of 400 μmol•m−2•s−1 was most conducive to the growth, development, and accumulation of the medicinal ingredients in D. denneanum. Transcriptome analysis revealed that the difference genes between the 400 μmol•m−2•s−1 treatment and CK (white light) were mostly enriched in the metabolic pathways of MAPK signaling, phenylpropanoid biosynthesis and flavonoid biosynthesis. Among them, CAM, PP2C, PYR1 may be the critical genes regulating the growth and development of D. denneanum. The combination of CAM and Ca2+ activates MPKs to maintain ROS homeostasis in D. denneanum. PP2C and PYR1 induced ABA synthesis to control the growth, development, and resistance of D. denneanum. Moreover, 4CL, CAD, BGLU, CCoAOMT and CHI may be the hub genes involved in regulating the synthesis of its key medicinal ingredients. This experiment provides scientific evidence for the application of red-blue light in the artificial cultivation in D. denneanum, and offers the mechanism of in-depth research foundation.

Blue light strongly promotes de-etiolation over green, moderate over red, but have limited action over far-red lights in lettuce plants

The role of photoreceptors (phytochromes and cryptochromes) was evaluated in lettuce regarding (de)etiolation processes. The manipulation of light quality and intensity can modulate their activity and response and, consequently, promote morphophysiological changes in plants. To this end, lettuce plants were grown under controlled conditions at two photosynthetically active radiation levels (300 and 600 µmol m−2 s−1) and at different qualities, including white, blue, green, red and far-red light, as well as combinations, totaling 18 treatments. Biomass gain, internode length, light interception, pigment content, morpho-anatomical changes in the leaves and ultrastructural changes in the chloroplast and cell wall were evaluated. It was verified that in green, there was the highest degree of etiolation; however, the supplementation of blue promotes a strong de-etiolation process. In pure red (R), the plants were slightly less etiolated, but with limited action of blue in stimulating de-etiolation, and in R plus far-red (FR) (R:FR ratio was 0.33 in R + FR treatment), there was a strong degree of etiolation and weak action of blue on those set of treatments. In general, the plants submitted to the highest intensities of blue light, alone or in combination, approach the control phenotype (white light at total 300 µmol m−2 s−1; 18 % blue = 54 µmol m−2 s−1). The morpho-anatomical phenotype supports the hypothesis that blue light is capable of inhibiting or reducing etiolation-related responses, but the effects are dependent not only on the quality alone but also on the light intensity. Based on the known light-dependent response of phytochromes and cryptochromes, we suggest a weak interference of PHYB on CRY and a strong negative action of PHYA on CRY proteins.

Strawberry (Fragaria ananassa) seedlings formation under different intensities of violet, blue and red LED light

Introduction. Seedlings formation under controlled conditions is essential for growing species of importance as strawberry. Since the artificial LED lighting technologic has allowed greater control of light, the variation of components such as the wavelength and intensity can be manipulated to form seedlings with different characteristics. However, it is necessary to generate original scientific information for the development of precise and efficient practices on light control. Objective. The aim of the present study was to evaluate the strawberry seedlings formation under different intensities of violet, blue and red LED light. Material and methods. The study was performed in 2020 at the Plant Genetics Laboratory of the Agronomy Department of the Universidad de Guanajuato, in the municipality of Irapuato, in the state of Guanajuato, Mexico. Seeds were recovered from San Andreas cultivar fruits and seedlings were formed under violet, blue and red LED light at high, medium, and low intensities. Color determination of cotiledon area, chroma saturation index and Hue angle were performed. Physiotechnical variables, chemical and antioxidant activity were measured. Results. The most suitable treatments were violet light of high and medium intensities; as well as blue light of high intensity, due to the germination percentage exceeded at least 60 %. Seedlings did not lengthen or thin, presented the largest cotyledons areas and the highest chlorophyll concentrations. In addition, these light treatments consumed 31.2 % less electrical energy on average. Conclusions. Besides the white light, the most suitable treatments for strawberry seedlings formation were violet light at high and medium intensities, as well as blue light at high intensity. It is suggested that the violet and blue light treatments be evaluated in other cultivars to confirm the beneficial effect on the strawberry seedlings. Red light limited germination and the highest antioxidant activity was observed in this treatment.