Full-spectrum White Light Research Articles

Absolutely Structural Disorder Boosting Bandwidth toward Full-Spectrum White Light from Single Occupancy of Activator.

Achieving single-phase full-spectrum white light (SFWL) phosphors is a central goal in theoptical field because they simplify white-LEDs assembly and avoid long-term color instability. Despite many approaches are developed, current SFWL phosphors still suffer from chromaticity drift due to inconsistent thermal quenching of multiple emitting centers. Herein, an absolutely structural disorder strategy is established to develop a single-emitting center-based SFWL phosphor. Precisely controlling the flux added induces a structural translation from the absolutely ordered Y0.75Ta0.25O1.75:Bi3+ to the absolutely disordered Y0.785Ta0.215O1.715:Bi3+, as directly identified by STEM-HAADF analyses. Structural disorder enables Y0.785Ta0.215O1.715:Bi3+ to produce SFWL with the FWHM of 6194cm-1 (175nm) by employing a single activator site, a 1352cm-1 increase compared to the cyan-emitting Y0.75Ta0.25O1.75:Bi3+ despite Bi3+ occupies two lattice positions. This single-emitting center-based SFWL, coupled with minimal thermal expansion of the unit cell and inapparent spectral overlap of excitation and emission bands, ensure zero-chromaticity shift with elevated temperature. A prototype white-LEDs using Y0.785Ta0.215O1.715:Bi3+ as a single luminescent layer generates warm white light without perceptible CIE coordinates shift under various currents or after extremely long-term continuous operation. This work highlights the potential of structural disorder in designing SFWL phosphors with exceptional color stability.

Local structure engineering of Ba1-xKxLa2Y2(SiO4)2O1-α: Eu2+ green phosphors for violet-light-excitable full-spectrum lighting

To achieve comfortable and healthy full-spectrum lighting, the development of efficient and stable violet-light-excitable phosphors is urgently required. Herein, we report a new type of green-emitting phosphor, Ba1-xKxLa2Y2(SiO4)2O1-α: Eu2+ (x=0–1). Interestingly, K+-alloying leads to continuous redshift of green emission from 500 nm to 517 nm accompanied with reduced full width at half maximum (FWHM) from 72 nm to 63 nm and enhanced excitation intensity in the violet spectral region. Rietveld refinements and spectral analysis evidence that K+-addition enhances the distortion of [M(Ⅰ)O9] and [M(Ⅱ)O7] (M(Ⅰ/Ⅱ) = Ba, La, Y, K) polyhedron and strengthens crystal field around Eu2+, which is responsible for the observed photoluminescence (PL) phenomenon. Finally, we design a full-spectrum white light emitting diode (WLED) with an ultra-high color rendering index (CRI, Ra) of 97.4 by coupling the as-prepared green-emitting phosphor (Ba0.7K0.3La2Y2(SiO4)2O1-α: Eu2+) and commercial blue/red phosphors with a violet LED chip, which demonstrates significant potential for application in healthy solid-state lighting.

Full-Spectrum White-Light Emission from Triple Self-Trapped Excitons in Hybrid Mixed-Metal Halides.

Low-dimensional metal halides with broadband emissions are expected to serve as downconversion luminescent materials for solid-state lighting (SSL). However, efficiently generating full-spectrum white-light emission with a high color-rendering index (CRI) in single-phase emitters remains a challenge. Here, we report a novel zero-dimensional (0D) hybrid mixed-metal halide (TPA)2CuAgI4 (TPA = tetrapropylammonium), in which individual [CuAgI4]2- dimers are completely isolated and surrounded by the organic cations TPA+. Cu+ and Ag+ share the same crystallographic site in [CuAgI4]2- dimers with the same statistical probability. Upon photoexcitation, single crystals exhibit a full-spectrum white-light emission with a full width at half-maximum (fwhm) of up to 314 nm and a high quantum efficiency of 46.8%. Detailed photophysical studies and theoretical calculations reveal that the ultra-broadband emission of (TPA)2CuAgI4 originates from the radiative recombination of red-, green-, and blue-emitting self-trapped excitons in [CuAgI4]2- dimers. In addition, (TPA)2CuAgI4 nanocrystals were successfully synthesized and exhibited optical properties similar to those of single-crystal counterparts. Finally, a prototype ultraviolet (UV)-pumped white-light-emitting diode (WLED) and a composite thin film employing this new white-light emitter produces a well-distributed full-spectrum white light with a high CRI of 91.4 and a warm correlated color temperature (CCT) of 4135 K, indicating the potential application of this white-light emitter in SSL. These results provide a new perspective for designing superior single-phase white-light emitters.

Charge compensator adjusts the luminescence intensity of ZnWO4: Sm3+ full spectrum phosphors: A bifunctional phosphors for plant growth lights and FIR thermometers

Full spectrum white LED plant growth light sources are suitable for use in conditions requiring a high color rendering index. In addition to red and blue light, green light was shown to have a positive impact on plant growth in earlier studies. In this work, a series of Sm3+ doped ZnWO4 phosphors was prepared using the high-temperature solid-state reaction method. Li+ serves as a charge compensator to reduce lattice defects caused by non-equivalent isomorphism. XRD measurements and Rietveld refinement were used to investigate the phase composition and structural properties of the samples. The luminescent properties of the samples were tested using a fluorescence spectrophotometer. The Li + introduction can significantly improve the energy transfer from the matrix to Sm3+ and the luminescence intensity of Sm3+. In addition, this phenomenon was explained with non-equivalent isomorphism and the charge density difference diagram. The LED lamp was prepared using ZnWO4: 0.004Sm3+, 0.004Li + phosphor and LED chip. The emitted full spectrum light can match well with the absorption spectrum of plant pigments. The color rendering index of the LED lamp is greater than 91. And the comparative experiment of plant cultivation shows that the prepared LED plant lamp has good effects. The dependence of luminescence properties of ZnWO4: 0.004Sm3+, 0.004Li+ phosphor on temperature was determined. Based on fluorescence intensity ratio (FIR) technology, the maximum SaMAX and SrMAX are 52 % K−1 at 453 K and 9.31 % K−1 at 303 K, respectively. As the temperature increases, the chromaticity shift (Δs) value is 0.254. The benefits of the ZnWO4: 0.004Sm3+, 0.004Li+ phosphor are the straightforward synthesis process, low cost, pure phase, full spectrum, high color rendering index, tunable red-to-blue ratio, and temperature monitoring function. Therefore, this phosphor is an ideal material in plant growth and optical temperature measurement.

Synthesis and luminescent properties of a new cyan Ca18Li6-3xYx(PO4)14:0.1Eu phosphors and PVA-based composite films for multifunctional applications

The development of light-emitting materials capable of efficiently emitting broad-band cyan light is of paramount importance in the quest for full-spectrum white light illumination. In this study, a series of new Ca18Li6-3xYx(PO4)14:0.1Eu phosphors with adjustable luminescent properties were synthesized through a high-temperature solid-phase method, and the investigation encompassed an analysis of their crystal structures, luminescence characteristics, and thermal stability. Meanwhile, the optimal doping concentration of Y3+ ions in the Ca18Li6-3xYx(PO4)14:0.1Eu host was identified to be x = 0.3, achieved through the modulation of the substitution ratio of Y3+ to Ca2+ to regulate the occupancy of Eu2+ at different sites. The resulted in the generation of asymmetric cyan color emission spectra (FWHM = 47 nm) with broad-band emission spanning the 425–550 nm range under 378 nm excitation. In addition, the application of the optimized cyan-emitting phosphor Ca18Li5.1Y0.3(PO4)14:0.1Eu in w-LED devices led to a significant enhancement in the CRI from 89.1 to 91.2, accompanied by a reduction in the correlated color temperature from 4896 K to 4566 K. These results highlight the potential utility of the cyan-emitting Ca18Li5.1Y0.3(PO4)14:0.1Eu phosphors in full-visible-spectrum solid-state illumination. Notably, the optimized cyan-emitting phosphor Ca18Li5.1Y0.3(PO4)14:0.1Eu was synthesized in conjunction with soluble polyvinyl alcohol (PVA) to yield a transparent anti-counterfeiting ink. The resulting film exhibited exceptional flexibility, foldability, and superior thermal and optical properties. Moreover, the emission band of this phosphor, situated in the 425 nm–550 nm spectral region, represents a crucial blue light source beneficial for plant growth. In summary, the highly efficient phosphor Ca18Li5.1Y0.3(PO4)14:0.1Eu is a promising material with multifunctional luminescent potential for general illumination, anti-counterfeiting, and light-converting agricultural films.

Tunable luminescence spectra of solid solution phosphors Gd3(Sb1-yTay)O7:Bi3+ for ultrahigh color rendering index full-spectrum white light-emitting diodes

The development of efficient luminescent materials that can compensate for the cyan gap is essential for actualizing high-quality full-spectrum white light-emitting diode (wLED) illumination. In this paper, a novel blue-emitting phosphor Gd3SbO7:Bi3+ was synthesized with an emission center located at 449 nm. Based on the cation substitution strategy, the cyan-emitting Gd3TaO7:Bi3+ phosphor is developed by completely replacing Sb5+ ions with Ta5+ ions in Gd3SbO7:Bi3+. Compared with Gd3SbO7:Bi3+, Gd3TaO7:Bi3+ also has an orthorhombic phase with the space group Ccmm, except that its emission wavelength is red-shifted by 45 nm from 449 to 494 nm, and the luminescence color is changed from blue to cyan. Thermal stability measurements demonstrate the negative effect of increasing Ta5+ doping concentration on the thermal stability of Gd3SbO7:Bi3+ phosphors. And a full-spectrum wLED device was fabricated using Gd3SbO7:Bi3+, Gd3TaO7:Bi3+, commercial (Sr, Ba)2SiO4:Eu2+ and CaAlSiN3:Eu2+ phosphors, with an impressive color rendering index (Ra = 94.7, R9 = 93) and suitable correlated color temperature (5832 K). The research results demonstrate the important role of Gd3TaO7:Bi3+ phosphors in compensating the cyan gap, and also provide new insights into the application of cyan phosphors in full-spectrum white light illumination.

Full-spectrum and tunable white light emission of germanate glass-ceramic containing defective Zn2GeO4 and Mn2+ ions

The full-spectrum phosphors are key components for improving the light quality of phosphor-converted white light-emitting diodes (pc-WLEDs). In this work, a novel germanate glass-ceramic (GC) doped with Mn2+ was developed to achieve full-spectrum white light emission deriving from the defective Zn2GeO4 crystalline phase and Mn2+ with multisite occupancy. The defective Zn2GeO4 is crystallized in situ from the well-designed precursor germanate glass by a controllable heat treatment. The energy states of intrinsic defects, including oxygen and zinc vacancies and interstitial zinc and oxygen of Zn2GeO4 in GC, have been studied by first-principles calculations. The luminescence property and the energy transfer mechanism between the defect states and Mn2+ ions in the GC material was proposed. Under the UV excitation, the luminescence property can be tuned by adjusting the distribution of Mn2+ ions in between the glassy and crystalline phases. The correlated color temperature (CCT) and color rendering index (CRI) of the UV-excited full-spectrum white light emission can be tuned over a wide range. This combinatorial strategy of intrinsic defects and multisite ion doping for full-spectrum white light emission in GC, which overcomes the limitation of conventional discontinuous white light emitting materials that emit singly from doping ions, has shown good potential for application in pc-WLEDs.

Short-wavelength artificial light affects visual neural pathway development in mice

Nearly all modern life depends on artificial light; however, it does cause health problems. With certain restrictions of artificial light emitting technology, the influence of the light spectrum is inevitable. The most remarkable problem is its overload in the short wavelength component. Short wavelength artificial light has a wide range of influences from ocular development to mental problems. The visual neuronal pathway, as the primary light-sensing structure, may contain the fundamental mechanism of all light-induced abnormalities. However, how the artificial light spectrum shapes the visual neuronal pathway during development in mammals is poorly understood. We placed C57BL/6 mice in three different spectrum environments (full-spectrum white light: 400–750 nm; violet light: 400 ± 20 nm; green light: 510 ± 20 nm) beginning at eye opening, with a fixed light time of 7:00–19:00. During development, we assessed the ocular axial dimension, visual function and retinal neurons. After two weeks under short wavelength conditions, the ocular axial length (AL), anterior chamber depth (ACD) and length of lens thickness, real vitreous chamber depth and retinal thickness (LLVR) were shorter, visual acuity (VA) decreased, and retinal electrical activity was impaired. The density of S-cones in the dorsal and ventral retinas both decreased after one week under short wavelength conditions. In the ventral retina, it increased after three weeks. Retinal ganglion cell (RGC) density and axon thickness were not influenced; however, the axonal terminals in the lateral geniculate nucleus (LGN) were less clustered and sparse. Amacrine cells (ACs) were significantly more activated. Green light has few effects. The KEGG and GO enrichment analyses showed that many genes related to neural circuitry, synaptic formation and neurotransmitter function were differentially expressed in the short wavelength light group. In conclusion, exposure to short wavelength artificial light in the early stage of vision-dependent development in mice delayed the development of the visual pathway. The axon terminus structure and neurotransmitter function may be the major suffering.

Dynamic spectrum lighting impact on plant morphology and cannabinoid profile of medical and recreational cannabis – A novel leapfrog strategy towards shaping the future of horticulture lighting

It is well documented that the light is the main factor or one of the factors influencing plant growth and development. The role of light spectral quality in meeting the specific needs during a plant’s developmental stages (germination, vegetative and flowering) has not been well defined and investigated. The objective of this study was to investigate the impact of light spectral quality on the growth and yield of cannabis plants during different developmental stages. Cannabis plants were grown in a controlled environment with distinct light spectral quality treatments applied at different growth stages. The plants were monitored for morphological responses and cannabinoid content. This study evaluated the hypothesis that, just like the dietary needs of human beings change with age, plants' nutritional and lighting requirements change with their growth stage. Plants' metabolic responses can be triggered and maximized by giving them the right light spectrum and intensity as the plant undergoes the development phases of its cycle. The results showed that the dynamic spectrum lighting led to a 33 % increase in yield and significant improvement in cannabinoid content. These findings challenge the conventional belief that a fixed full-spectrum white light is optimal for plant growth and development. Furthermore, it is hypothesized that plant development stages can be divided into more than the existing three conventional stages. This optimization resulted in the highest yield and energy savings under the dynamic spectrum. These novel findings will have important implications in motivating plant scientists to go beyond the conventional norm and could pave the way for a paradigm shift towards dynamic spectrum lighting, thus taking a leapfrog jump in shaping the future of horticulture lighting.

Luminescence characteristics of Ce3+/Eu2+ activated (Ba, Sr)3YB3O9 phosphors

The Ce3+/Eu2+ activated Ba3YB3O9 and Ba1·5Sr1·5YB3O9 phosphors were prepared using solid state reactions under the reducing atmosphere. Then, their phase and fluorescence performance were investigated carefully. The XRD measurements demonstrate that the synthesized phosphors have the single phase. For the Ce3+/Eu2+ single activated Ba3YB3O9 and Ba1·5Sr1·5YB3O9 phosphors, they respectively show blue and yellow emission, meaning it is possible to generate white light by the Ce3+/Eu2+ coactivated phosphors. Due to the Ce3+ → Eu2+ energy transfers, tunable luminescence was generated by the Ce3+/Eu2+ coactivated Ba3YB3O9 and Ba1·5Sr1·5YB3O9 phosphors. The light of most of the Ce3+/Eu2+ coactivated Ba3YB3O9 and Ba1·5Sr1·5YB3O9 phosphors locates in the white light region. In addition, the substitution of Sr2+ to Ba2+ benefits to obtain the full spectrum white light.

Effects of light therapy on sleep/wakefulness, daily rhythms, and the central orexin system in a diurnal rodent model of seasonal affective disorder

BackgroundBright light therapy (BLT) is the first-line treatment for seasonal affective disorder. However, the neural mechanisms underlying BLT are unclear. To begin filling this gap, the present study examined the impact of BLT on sleep/wakefulness, daily rhythms, and the wakefulness-promoting orexin/hypocretin system in a diurnal rodent, Nile grass rats (Arvicanthis niloticus). MethodsMale and female grass rats were housed under a 12:12 h light/dark cycle with dim light (50 lx) during the day. The experimental group received daily 1-h early morning BLT (full-spectrum white light, 10,000 lx), while the control group received narrowband red light for 4 weeks. Sleep/wakefulness and in-cage locomotor activity were monitored, followed by examination of hypothalamic prepro-orexin and orexin receptors OX1R and OX2R expression in corticolimbic brain regions. ResultsThe BLT group had higher wakefulness during light treatment, better nighttime sleep quality, and improved daily rhythm entrainment compared to controls. The impact of BLT on the orexin system was sex- and brain region-specific, with males showing higher OX1R and OX2R in the CA1, while females showed higher prepro-orexin but lower OX1R and OX2R in the BLA, compared to same-sex controls. LimitationsThe present study focused on the orexin system in a limited number of brain regions at a single time point. Sex wasn't a statistical factor, as male and female cohorts were run independently. ConclusionsThe diurnal grass rats show similar behavioral responses to BLT as humans, thus could be a good model for further elucidating the neural mechanisms underlying the therapeutic effects of BLT.

Anionic Regulation toward Bi3+ Selective Occupation for Full-Spectrum White Light Emission.

An activator's selective occupation of a host is of great significance for designing high-quality white light-emitting diode phosphors, while achieving a full-spectrum single-phase white light emission phosphor is challenging. In this study, a boron phosphate solid-solution Na2Y2(BO3)2-x(PO4)xO:0.005 Bi3+ (NYB2-xPxO:0.005 Bi3+) white phosphor was designed by selectively occupying Bi3+ activators in the mixed anionic groups. The substitutes of the anionic unit (BO3)3- by the (PO4)3- unit are supposed to force part of the Bi3+ ion to enter the Na lattice site, which produces an intense orange-red emission peaked at 590 nm. In parallel, spectral tuning from blue to white light and an internal quantum efficiency of 56.42% was obtained, and the thermal stabile luminescence intensity remains at 94.2% of the initial intensity after four heating-cooling cycles from 30 to 210 °C (luminescent intensity is 83.6% of room temperature (RT) at 150 °C, with excellent thermal stability and recovery performance). Finally, an excellent color rendering index (Ra = 90.8 and R9 = 85) was demonstrated for white light-emitting diode devices using only an NYB1.5P0.5O:0.005 Bi3+ phosphor and a near-ultraviolet (n-UV) 365 nm LED chip. This work delves into the different selective occupancy of Bi3+ ions and explores a new avenue for the design of phosphors for full-spectrum white light emission.

Plant-Growth Promoting Microbes Change the Photosynthetic Response to Light Quality in Spinach.

In this study, the combined effect of plant growth under different light quality and the application of plant-growth-promoting microbes (PGPM) was considered on spinach (Spinacia oleracea L.) to assess the influence of these factors on the photosynthetic performance. To pursue this goal, spinach plants were grown in a growth chamber at two different light quality regimes, full-spectrum white light (W) and red-blue light (RB), with (I) or without (NI) PGPM-based inoculants. Photosynthesis-light response curves (LRC) and photosynthesis-CO2 response curves (CRC) were performed for the four growth conditions (W-NI, RB-NI, W-I, and RB-I). At each step of LRC and CRC, net photosynthesis (PN), stomatal conductance (gs), Ci/Ca ratio, water use efficiency (WUEi), and fluorescence indexes were calculated. Moreover, parameters derived from the fitting of LRC, such as light-saturated net photosynthesis (PNmax), apparent light efficiency (Qpp), and dark respiration (Rd), as well as the Rubisco large subunit amount, were also determined. In not-inoculated plants, the growth under RB- regime improved PN compared to W-light because it increased stomatal conductance and favored the Rubisco synthesis. Furthermore, the RB regime also stimulates the processes of light conversion into chemical energy through chloroplasts, as indicated by the higher values of Qpp and PNmax in RB compared to W plants. On the contrary, in inoculated plants, the PN enhancement was significantly higher in W (30%) than in RB plants (17%), which showed the highest Rubisco content among all treatments. Our results indicate that the plant-growth-promoting microbes alter the photosynthetic response to light quality. This issue must be considered when PGPMs are used to improve plant growth performance in a controlled environment using artificial lighting.

Ba5GeO4Br6:Bi3+, a promising cyan phosphor for high-quality full-spectrum white light illumination

Using efficient cyan phosphors to reduce the cyan gap in the white light-emitting diode spectrum plays an important role in realizing full-spectrum white light illumination. In this work, herein, we successfully prepared a cyan phosphor Ba5GeO4Br6:Bi3+ by high-temperature solid-state method to compensate for the cyan gap in the spectrum and studied its crystal structure, luminescent properties, and thermal quenching behavior. Meanwhile, the valence state of Bi ions in the phosphor was determined by XPS spectroscopy. The Ba5GeO4Br6:Bi3+ phosphor shows strong absorption in the range of 250–400 nm, which can be attributed to the 1S0→3P1 transition of Bi3+. When excited at UV light, Ba5GeO4Br6:Bi3+ gives a bright and broad cyan emission with a half width at half maximum (FWHM) of 138 nm, and the emission peak at 491 nm. In addition, as the temperature increases, the blue shift and broadening of the spectrum can be elucidated by the nonradiative transfer and the increase of the thermally active phonon density. Finally, a full-spectrum WLED lamp with a color rendering index of 93.4 was prepared by coating Ba5GeO4Br6:Bi3+ phosphor, commercial BaMgAl10O17:Eu2+ and (Ca,Sr)AlSiN3:Eu2+ phosphors on a 310 nm UV LED chip.

Research Advances of Continuous-wave Laser Driven Full-spectrum White Light Based on Inorganic Material System

Research Advances of Continuous-wave Laser Driven Full-spectrum White Light Based on Inorganic Material System

Eu2+-activated MgAl2Si4O6N4: a novel oxonitridoalumosilicate blue phosphor for white LEDs.

Recently, blue-emitting phosphors have attracted great interest due to their application in full-spectrum white light illumination. In this paper, a novel blue-emitting MgAl2Si4O6N4:Eu2+ phosphor was successfully synthesized through the solid-state reaction method in a reducing atmosphere. Under the excitation of near-ultraviolet (n-UV) light, the MgAl2Si4O6N4:0.02Eu2+ phosphor effectively emits a broad blue emission band centered at 456 nm with the FWHM as large as 81 nm. With the increasing Eu2+ concentration, the emission bands of MgAl2Si4O6N4:Eu2+ shift to a shorter wavelength and the FWHMs broaden gradually. Moreover, the MgAl2Si4O6N4:0.02Eu2+ phosphor exhibits a slight thermal quenching at a higher temperature. After fabricating the as-prepared MgAl2Si4O6N4:0.02Eu2+ phosphor into a white LED device, the intense neutral white light emission is obtained with excellent CRI (87.4) and CCT (5645 K). These results suggest that the blue MgAl2Si4O6N4:Eu2+ phosphor is a promising candidate in n-UV excited white LEDs.

Photosynthetic spectral response curves of saffron leaves.

Saffron (Crocus sativus L.) is an herb with outstanding medicinal functions and commercial value. Light is an important factor in plant growth, and the sensitivity of plant photosynthesis to light quality can be characterized by photosynthetic spectral response curves. This study aims to measure the spectral response curves of saffron leaves so as to provide theoretical guidance for a supplemental lighting spectrum to increase saffron production. The measurement results show the peaks of spectral response curves of saffron leaves are at 480 nm and 660 nm, which provides a reference for the peak wavelengths of supplemental lighting spectrum. Full-spectrum white light with low color temperature or red light mixed with a little blue light might be most beneficial for saffron biomass accumulation.

Fluorescence guided intraluminal endoscopy in the gastrointestinal tract: A systematic review.

BACKGROUNDConventional endoscopy is based on full spectrum white light. However, different studies have investigated the use of fluorescence based endoscopy systems where the white light has been supplemented by infrared light and the use of relevant fluorophores. Fluorescence endoscopy utilizes the fluorescence emitted from a fluorophore, visualizing what is not visible to the naked eye.AIMTo explore the feasibility of fluorescence endoscopy and evaluate its use in diagnosing and evaluating gastrointestinal disease.METHODSWe followed the PRISMA guidelines for this systematic review. The research covered five databases; PubMed, Scopus, Web of Science, Embase, and the Cochrane Collection, including only studies in English and Scandinavian languages. Authors screened title and abstract for inclusion, subsequently full-text for inclusion according to eligibility criteria listed in the protocol. The risk of bias was assessed for all studies according to the Newcastle-Ottawa Scale. The authors extracted the data and reported the results in both text and tables.RESULTSWe included seven studies in the systematic review after screening a total of 2769 papers. The most prominent fluorophore was indocyanine green (n = 6), and whereas one study (n = 1) used Bevacizumab 800-CW. Three studies investigated fluorescence endoscopy in detecting varices, adenomas in patients with familial adenomatous polyposis and neoplasms in the gastrointestinal tract. Four studies evaluated the usefulness of fluorescence endoscopy in assessing tumor invasion. Three of the four studies reported an exceptional diagnostic accuracy (93%, 89% and 88%) in assessing tumor invasion, thus representing better visualization and more correct diagnosis by fluorescence endoscopy compared with the conventional endoscopy. The relationship between the endoscopic findings, tumor invasion, and tumor vascularity was evaluated in two studies showing a significant correlation (dP < 0.05 and bP < 0.01).CONCLUSIONThe use of fluorescence endoscopy is a promising method adding diagnostic value in the detection of neoplasia, adenomas, and assessment of tumor invasion within the gastrointestinal tract. More studies are needed to utilize the feasibility of fluorescence endoscopy compared with other endoscopic methods.

Plant Perception of Light: The role of indoleamines in Scutellaria species

Light mediates plant growth through diverse mechanisms and signaling networks including plant growth regulators (PGRs). We hypothesized that a novel class of PGRs, the indoleamines, are plant signaling molecules that perceive changes in light composition and initiate a cascade of metabolic responses. We used three Scutellaria model species (skullcap): S. lateriflora, S. galericulata and S. racemosa that produce high levels of melatonin and serotonin to investigate this hypothesis. Axenic Scutellaria cultures were exposed to red, blue, green or full spectrum white light spectra provided by light emitting diode (LED) lighting systems, or daylight fluorescent bulbs. Melatonin (MEL), serotonin (5HT), abscisic acid (ABA), auxin (IAA), and jasmonic acid (JA), were quantified by liquid chromatography with tandem mass spectrometry. Melatonin was detected consistently in plants grown under blue light in all species of Scutellaria. In S. galericulata, significant quantities of ABA were detected in plants grown under white light but not detected in plants grown under other light spectra. In timeline studies of S. racemosa plants exposed to limited red or blue light spectra had significantly reduced levels of tryptamine (TRM), 5HT and MEL in the shoots initially but melatonin was detected after 12 hours and quantifiable amounts of 5HT were detected after 7 days. Supplementation of the culture medium with MEL or 5HT did not change the pattern of MEL in blue light grown cultures but did change patterns of 5HT accumulation. 5HT was highest in plants grown under red light immediately after culture and decreased over 7 days. These data indicate that the relative amounts of MEL and 5HT are responsive to light spectra and redirect metabolic resources to enable plant adaptations to changing environments.

Highly Efficient Cyan-Green Emission in Self-Activated Rb3RV2O8 (R = Y, Lu) Vanadate Phosphors for Full-Spectrum White Light-Emitting Diodes (LEDs).

Phosphor-converted white-light-emitting diodes (pc-WLEDs) rely on combining a near-ultraviolet (n-UV) or blue chip with trichromatic and yellow-emitting phosphors. It is challenging to discover cyan-green-emitting (480-520 nm) phosphors for compensating the spectral gap and producing full-spectrum white light. In this work, we successfully discovered two unprecedented bright cyan-green emitting Rb3RV2O8 (R = Y, Lu) phosphors that gives emission bands centered at 500 nm upon 362 nm n-UV light excitation. Interestingly, the both self-activated compounds exhibit high internal quantum efficiencies (IQEs) of 71% for Rb3YV2O8 and 85% for Rb3LuV2O8, respectively. Moreover, controllable emission color can be successfully tuned from cyan-green to orange-red across the warm white light region by design strategy of VO43- → Eu3+ energy transfer. The thermal quenching of as-prepared phosphors could be effectively mitigated by this design strategy. Finally, the as-fabricated n-UV (λex = 370 nm) pumped phosphor-converted (pc) W-LED devices utilizing Rb3RV2O8 (R = Y, Lu) along with commercial phosphors demonstrate well-distributed warm white light with high color-rendering index (CRI) of 91.9 and 93.5, and a low correlated color temperature (CCT) of 5095 and 4946 K. It suggests that the both vanadate phosphors have potential applications in full-spectrum pc-WLEDs.