Blue Light Research Articles

Halogen Engineering and Solvent-Induced Strategies Regulate Structural Transitions and Luminescence Switching of Hybrid Copper(I) Halides.

Copper-based halides have attracted significant attention due to their unique photophysical properties and diverse coordination configurations. However, enhancing water stability and modulating structural transitions in cuprous halide materials remain challenging. In this work, we successfully synthesized three copper(I) halides, (C24H28P)CuBr2 (L1, [C24H28P]+ = hexyltriphenylphosphonium), (C24H28P)2Cu4Br6 (L2), and (C24H28P)2Cu4I6 (L3), via solvent volatilization, demonstrating exceptional water stability even after 27 days of submersion. Crystals L1 and L2 emit yellow and orange light, respectively, under ultraviolet excitation, while L3 emits green light when excited by blue light. A rapid phase transition between L1 and L2 occurs when stimulated with methanol at room temperature. Further exposure of L2 to a NaI solution can result in substitution of Br- ions by I- in [Cu4Br6]2- to form L3. Multimodal anticounterfeiting luminescent labels with high-security levels have been successfully manufactured based on sequential L1 → L2 → L3 phase transition. Moreover, a test paper designed based on L1 can be applied for low-level methanol detection. This work successfully accomplishes the coregulation of structural transformations and luminescence switching in copper(I) halides by combining methanol simulations with halogen substitution strategies, which not only deepens the understanding of the structure-property relationships but also broadens the optical applications of these materials.

Red and blue LED light increases the survival rate of random skin flaps in rats after MRSA infection.

Skin flap transplantation is a conventional wound repair method in plastic and reconstructive surgery, but infection and ischemia are common complications. Photobiomodulation (PBM) therapy has shown promise for various medical problems, including wound repair processes, due to its capability to accelerate angiogenesis and relieve inflammation. This study investigated the effect of red and blue light on the survival of random skin flaps in methicillin-resistant Staphylococcus aureus (MRSA)-infected Sprague Dawley (SD) rats. Forty male SD rats were divided into control and light-emitting diode-red and blue light-treated (LED-RBL) groups at a ratio of 1:1 and a McFarland flap procedure was performed, which was subsequently infected with MRSA strains. After 7 days, the appearance and survival of the flaps were evaluated. The microvascular density was determined by hematoxylin and eosin (HE) staining. The expression levels of vascular endothelial growth factor (VEGF), hypoxia inducible factor 1α (HIF-1α), phosphatidylinositol 3-kinase (PI3K), and protein kinase B (normally expressed as AKT) were detected by immunohistochemistry. The flap survival rate and microvascular density in the LED-RBL group were significantly higher than those in the control group (P < 0.05). In addition, the VEGF, HIF1-α, PI3K, and AKT levels were significantly higher in the LED-RBL group compared to the control group (P < 0.05). Red and blue light increased the survival area of the infected flap in rats by promoting angiogenesis, relieving oxidative stress, and reducing bacterial loads, indicating that PBM therapy is a convenient, simple, analgesic, and safe treatment intervention in promoting the survival rate of transplanted flaps after wound repair surgery.

Green preparation of highly transparent nano-NH2-UiO(Zr)-66/cellulose composite films with high-strength, superior flame retardant and UV to high-energy blue light shielding performance.

From the perspective of sustainable development and practical applications, there is a significant demand for the design of advanced cellulose-based film materials with superior mechanical, optical, and functional properties utilizing environmentally friendly strategies. Herein, biodegradable, mechanically robust and flame-retardant cellulose films with adjustable optical performance were successfully fabricated by in situ synthesis of NH2-UiO(Zr)-66 via a DMF-free green process at room temperature. The results indicate that the introduction of NH2-UiO(Zr)-66 enables films to realize a desirable flame retardancy (the limiting oxygen index (LOI) increased significantly from 19.2 % to 32.9 %). The film self-extinguish quickly once removed from the flame, demonstrating a prominent flame resistance. Compared to the original film, the modified films demonstrate a significant reduction in the peak heat release rate and total heat released, decreasing from 186.6 to 26.8 W/g and 19.7 to 1.2 kJ/g, respectively. Encouragingly, the incorporation of nano-NH2-UiO(Zr)-66 enabled films to achieve excellent UV to high-energy blue light (HEBL) shielding competence (90.8-100 %, 99.6-100 %, and 60.9-89 % for UVB, UVA and HEBL) meanwhile retaining low haze (1.9-2.6 %) and high transmittance (86.2-90.9 %). Furthermore, the incorporation of nano-NH2-UiO(Zr)-66 was observed to enhance the mechanical strength. Overall, this film presents a promising alternative to conventional plastics used in various applications, including electronic devices and packaging materials.

Effect of nutritional stress and serum starvation on the optical absorbance of normal and malignant epithelial cell lines.

This brief report aimed to investigate the optical absorbance spectra of normal, dysplastic, and malignant epithelial cell lines under normal and nutritional stress conditions. HaCAT (keratinocyte), DOK (oral dysplastic), and oral squamous cell carcinoma (OSCC) cell lines (CA1, Luc4, SCC9) were evaluated regarding their optical absorbance after culture with 0-10% fetal bovine serum. Absorbance measurements indicated that HaCAT under serum starvation exhibited higher absorbance at blue (430nm) and near-infrared (906nm) wavelengths. DOK showed absorption at 440nm and 945nm. OSCC cells showed absorption peaks at blue (400-428nm) and near-infrared. These findings highlight the importance of tailoring PBM parameters to individual needs to achieve optimal absorption and effectiveness. Moreover, the higher absorption peaks in the blue region support further studies to elucidate the potential use of blue light in oral dysplastic lesions and OSCC.

Blue photoluminescence from active carboxyl adatoms on nanoporous anodic alumina films

Nanoporous anodic alumina (nPAA) films formed on aluminum in lower aliphatic carboxylic acids exhibit blue self-coloring and characteristic properties such as photoluminescence (PL), electroluminescence, and electron spin resonance. The blue colors are seemingly originated from the adsorbed radicals incorporating into the oxide during the aluminum anodization. However, there is lack of reports revealing the detailed activation mechanism of the adatoms in the complexes. This study investigates the blue PL and its correlation with the atomic and electronic structures of the active aluminum surface using multiple theoretical and experimental methods. The results show that the concentration of carboxylates at the nPAA surface is highly correlated with the blue colorization and manifest that unpaired electrons in carbon (derived from the carboxylates) bridging two aluminum atoms at surface can play as an active source of the blue colorization. Therefore, it is suggested that controlling the adsorption of the carboxylate on the alumina membrane having large surface-to-volume ratio can be an efficient way to generate the blue light for the optoelectronic applications.

Probing the Signal Transduction Mechanism of the Light-Activated Adenylate Cyclase OaPAC Using Unnatural Amino Acid Mutagenesis.

OaPAC, the photoactivated adenylyl cyclase from Oscillatoria acuminata, is composed of a blue light using FAD (BLUF) domain fused to an adenylate cyclase (AC) domain. Since both the BLUF and AC domains are part of the same protein, OaPAC is a model for understanding how the ultrafast modulation of the chromophore binding pocket caused by photoexcitation results in the activation of the output domain on the μs-s time scale. In the present work, we use unnatural amino acid mutagenesis to identify specific sites in the protein that are involved in transducing the signal from the FAD binding site to the ATP binding site. To provide insight into site-specific structural dynamics, we replaced W90 which is close to the chromophore pocket, F103 which interacts with W90 across the dimer interface, and F180 in the central core of the AC domain, with the infrared probe azido-Phe (AzPhe). Using ultrafast IR, we show that AzPhe at position 90 responds on multiple time scales following photoexcitation. In contrast, the light minus dark IR spectrum of AzPhe103 shows only a minor perturbation in environment between the dark and light states, while replacement of F180 with AzPhe resulted in a protein with no catalytic activity. We also replaced Y125, which hydrogen bonds with N256 across the dimer interface, with fluoro-Tyr residues. All the fluoro-Tyr substituted proteins retained the light-induced red shift in the flavin absorption spectrum; however, only the 3-FY125 OaPAC retained photoinduced catalytic activity. The loss of activity in 3,5-F2Y125 and 2,3,5-F3Y125 OaPAC, which potentially increase the acidity of the Y125 phenol by more than 1000-fold, suggests that deprotonation of Y125 disrupts the signal transduction pathway from the BLUF to the AC domain.

Quantum Dot Luminescence Microspheres Enable Ultra-Efficient and Bright Micro-LEDs.

Quantum dot (QD)-converted micrometer-scale light-emitting diodes (micro-LEDs) are regarded as an effective solution for achieving high-performance full-color micro-LED displays because of their narrow-band emission, simplified mass transfer, facile drive circuits, and low cost. However, these micro-LEDs suffer from significant blue light leakage and unsatisfactory electroluminescence properties due to the poor light conversion efficiency and stability of the QDs. Herein, the construction of green and red QD luminescence microspheres with the simultaneously high conversion efficiency of blue light and strong photoluminescence stability are proposed. These luminescence microspheres exhibit high external photoluminescence quantum yields exceeding 46% under 450nm excitation, along with excellent reliability against blue light, heat, and water-oxygen degradation, owing to the waveguide and spatial confinement effects of the microspheres. The microsphere-based green and red micro-LEDs achieve world-record external quantum efficiencies of 40.8% and 22.1%, respectively, and high brightness values of 1.7×108 and 7.6×107cdm-2, respectively. Finally, 0.6inch red, green, and blue monochrome micro-LED displays are demonstrated by integrating microsphere-converted micro-LED arrays with thin-film transistor backplanes, which show a pixel resolution as high as 1700 PPI and brightness exceeding 10000cdm-2.

Multifunctional applications enabled by tunable multi-emission and ultra-broadband VIS-NIR luminescence via energy transfer in Sn2+/Mn2+-doped lead-free Zn-based metal halides.

Metal halides are widely applied in solid-state lighting (SSL), optoelectronic devices, information encryption, and near-infrared (NIR) detection due to their superior photoelectric properties and tunable emission. However, single-component phosphors that can be efficiently excited by light-emitting diode (LED) chips and cover both the visible (VIS) and NIR emission regions are still very rare. To address this issue, (TPA)2ZnBr4:Sn2+/Mn2+ (TPA = [(CH3CH2CH2)4N]+) phosphors were synthesized by using the solvent evaporation method. The Sn2+ doping significantly enhances the luminescence of (TPA)2ZnBr4, and shifts the weak emission of blue light to efficient emissions in the red and NIR zones. Spectroscopic studies and density functional theory (DFT) calculations reveal that the emissions are attributed to the different levels of 3P1-1S0 in the [SnBr4]2- tetrahedron caused by Jahn-Teller distortion. More importantly, energy transfer from Mn2+ to Sn2+ enables ultra-broadband VIS-NIR emission across the 400-1000 nm range, with excitation-dependent tunable emission characteristics. These properties suggest that (TPA)2ZnBr4:Sn2+/Mn2+ has great potential as a high-performance, single-component luminescent material for applications in general lighting, NIR light source, and anti-counterfeiting labels.

Highly efficient green phosphor Ca4La(PO4)3O:Eu2+,Tb3+ for white LEDs.

Although the green light emission of Tb3+ ions can be effectively improved by utilizing energy transfer from Eu2+ to Tb3+ ions, obtaining phosphors with high quantum efficiency remains a major problem. Here, we have achieved a novel apatite-type structure Ca4La(PO4)3O (CLPO) containing Eu2+ and Tb3+ ions. The CLPO:Eu2+ is capable of being effectively excited by near-ultraviolet light and emits blue light at about 460 nm. Energy transfer from the Eu2+ to Tb3+ ions in CLPO:Eu2+,Tb3+ can be readily constructed by utilizing the energy transfer from Eu2+ to Tb3+ ions. The optimized phosphor CLPO:0.02Eu2+,0.7Tb3+ has a high internal quantum efficiency of 96.6% and an external quantum efficiency of 64.7%. CLPO:0.02Eu2+,0.7Tb3+ and commercially available blue and red phosphors were coupled with a 365 nm chip package to form WLEDs, which presented a good Ra value (89.9) and correlated color temperature (3808 K). Our work provides an avenue to realize novel and efficient green phosphors by selecting suitable hosts and constructing efficient energy transfer.

Light quality affects chlorophyll biosynthesis and photosynthetic performance in Antarctic Chlamydomonas.

The perennially ice-covered Lake Bonney in Antarctica has been deemed a natural laboratory for studying life at the extreme. Photosynthetic algae dominate the lake food webs and are adapted to a multitude of extreme conditions including perpetual shading even at the height of the austral summer. Here we examine how the unique light environment in Lake Bonney influences the physiology of two Chlamydomonas species. Chlamydomonas priscui is found exclusively in the deep photic zone where it receives very low light levels biased in the blue part of the spectrum (400-500nm). In contrast, Chlamydomonas sp. ICE-MDV is represented at various depths within the water column (including the bright surface waters), and it receives a broad range of light levels and spectral wavelengths. The psychrophilic character of both species makes them an ideal system to study the effects of light quality and quantity on chlorophyll biosynthesis and photosynthetic performance in extreme conditions. We show that the shade-adapted C. priscui exhibits a decreased ability to accumulate chlorophyll and severe photoinhibition when grown under red light compared to blue light. These effects are particularly pronounced under red light of higher intensity, suggesting a loss of capability to acclimate to varied light conditions. In contrast, ICE-MDV has retained the ability to synthesize chlorophyll and maintain photosynthetic efficiency under a broader range of light conditions. Our findings provide insights into the mechanisms of photosynthesis under extreme conditions and have implications on algal survival in changing conditions of Antarctic ice-covered lakes.

A combined recombinase polymerase amplification CRISPR/Cas12a assay for detection of Fusarium oxysporum f. sp. cubense tropical race 4

The soilborne pathogen Fusarium oxysporum f. sp. cubense tropical race 4 (Foc TR4) is currently devastating banana production worldwide. Once introduced, it is not possible to eradicate the pathogen from soils where it can survive for decades. The only management option available then is to replace Foc TR4-susceptible with -resistant varieties. Timely detection of the pathogen, however, is an important strategy to prevent the introduction of Foc TR4 into new areas and prevent its spread from infested sites. In this study, a single-tube detection technique was developed by combining recombinase polymerase amplification (RPA) and clustered regularly interspaced short palindromic repeats (CRISPR)/Cas12a technology (RPA-Cas12a) for detection of Foc TR4. The RPA-Cas12a assay was conducted isothermally, had a sensitivity of up to 10 fg target DNA and did not cross react with any of the 76 non-target isolates included in the specificity testing. The RPA-Cas12a assay detected Foc TR4 from naturally infected banana samples collected in the field and visualization was possible with the naked eye under LED blue light transillumination. The method can be integrated with inexpensive fluorescent or electronic detection devices to accelerate Foc TR4 in-field detection and, thereby, fast-track disease containment strategies.

Blue light-emitting diode therapy for recurrent vulvovaginal candidiasis: a Brazilian report.

RVVC is defined as four or more episodes of candidiasis in a 12-month period. Conventional treatment is complex and often involves long-term medication use or multiple treatments. ABL therapy is a promising treatment option as it is acceptable to women and has only rare side effects. We conducted a prospective study with the objective of assessing the effects of antimicrobial blue light (ABL) therapy for recurrent vulvovaginal candidiasis (RVVC) in drug-resistant women. Our study enrolled RVVC drug-resistant women (defined based on clinical non-response to standard azole therapies confirmed through culture or persistence of VVC symptoms (oedema, erythema, pruritus, burning, dysuria and leucorrhea)), who received ABL through 10 sessions for 20min once a week from January 2023 to January 2024. The symptoms of Recurent VVC were assessed after 10 treatment sections and after 6 months. We included 62 patients. The overall symptoms improvement were 79% immediately after treatment and 58% after 6 months, respectively. There was an improvement in the symptoms of pruritus, burning, oedema, erythema and leucorrhoea. ABL was an effective therapy to be employed in drug-resistant women suffering from RVVC.

Optimizing Phaeodactylum tricornutum cultivation: integrated strategies for enhancing biomass, lipid, and fucoxanthin production

BackgroundPhaeodactylum tricornutum is a versatile marine microalga renowned for its high-value metabolite production, including omega-3 fatty acids and fucoxanthin, with emerging potential for integrated biorefinery approaches that encompass biofuel and bioproduct generation. Therefore, in this study we aimed to optimize the cultivation conditions for boosting biomass, lipid, and fucoxanthin production in P. tricornutum, focusing on the impacts of different nutrient ratios (nitrogen, phosphorus, silicate), glycerol supplementation, and light regimes.ResultsOptimized medium (− 50%N%, + 50% P, Zero-Si, 2 g glycerol) under low-intensity blue light (100 μmol m⁻2 s⁻1) improved biomass to 1.6 g L⁻1, with lipid productivity reaching 539.25 mg g⁻1, while fucoxanthin increased to 20.44 mg g−1. Total saturated fatty acid (ΣSFA) content in the optimized culture increased approximately 2.4-fold compared to the control F/2 medium. This change in fatty acid composition led to improved biodiesel properties, including a higher cetane number (59.18 vs. 56.04) and lower iodine value (53.96 vs 88.99 g I2/100 g oil). The optimized conditions also altered the biodiesel characteristics, such as kinematic viscosity, cloud point, and higher heating value.ConclusionOur optimization approach reveals the significant potential of P. tricornutum as a versatile microbial platform for biomass, lipid, and fucoxanthin production. The tailored cultivation strategy successfully enhanced biomass and lipid accumulation, with notable improvements in biodiesel properties through strategic nutrient and light regime manipulation. These findings demonstrate the critical role of precise cultivation conditions in optimizing microalgal metabolic performance for biotechnological applications.

Photoprotective Effects of Phytochemicals on Blue Light-Induced Retinal Damage: Current Evidence and Future Perspectives.

The widespread use of light-emitting diodes (LEDs) has increased blue light (BL) exposure, raising concerns about its potential adverse effects on ocular health. Prolonged exposure to BL has been implicated in the pathogenesis of various retinal disorders, including age-related macular degeneration (AMD), primarily through mechanisms involving oxidative stress and inflammation mediated by the overproduction of reactive oxygen species (ROS). This review synthesizes current evidence on the photoprotective properties of dietary bioactive compounds, (e.g., anthocyanins, curcumin, quercetin, myricetin, and resveratrol), with a focus on their potential to mitigate BL-induced retinal damage. Accumulating research suggests that dietary antioxidants, particularly polyphenols, may offer photoprotective benefits. These phytochemicals act by neutralizing ROS and enhancing the retina's endogenous antioxidant capacity. Based on these findings, this review advocates for a food-first approach in future investigations, emphasizing the development of evidence-based dietary recommendations to bolster retinal health and mitigate the risk of BL-related ocular diseases. Considering the current lack of empirical clinical studies examining the impact of BL on human ocular health, future research in the field of BL hazard should prioritize two key approaches: conducting large-scale epidemiological dietary surveys and implementing clinical trials on functional ingredients that have demonstrated beneficial effects against photodamage in preclinical animal studies.

Photodynamic Therapy Effects with Curcuma longa L. Active Ingredients in Gel and Blue LED on Acne: A Randomized, Controlled, and Double-Blind Clinical Study

Photodynamic therapy (PDT) using the photosensitizer curcumin and blue light has a relevant effect on bacteriological decontamination caused by C. acne. The aim is to verify PDT’s effectiveness with curcumin in individuals diagnosed with moderate to severe acne. This study was carried out on a total of 35 volunteers of both genders (12–32 years old), with moderate to severe acne vulgaris. The volunteers were randomized into five groups: L (LED), V (Vehicle), C (Curcumin), L + V (LED + Vehicle), and L + C (LED + Curcumin). The curcumin gel and LED with blue wavelength (450 nm ± 10 nm) were used. Qualitative and quantitative evaluations were used to verify the efficacy of the treatment by counting inflamed and non-inflamed lesions. The L + C group until day 30 showed a lower percentage of inflammatory lesions than the Vehicle group for the same period. On day 60, the L + C group showed lower inflammatory lesion values compared to the other groups. Intragroup analysis of hydration in the Vehicle group (V) showed a difference on days 30 and 60 compared to day zero. In an intragroup analysis, the L + C group showed a decrease in the mean scores on day 30, and day 60 compared to day zero, showing an improvement in the psychosocial status of these volunteers. Taken together, our results showed that the combination of blue LED therapy and curcumin proved to be an effective and safe treatment for reducing inflamed acne lesions in individuals with moderate to severe acne, while also enhancing their quality of life from a psychosocial perspective.

The resistance of Solanum lycopersicum photosynthetic apparatus to high-intensity blue light is determined mainly by the cryptochrome 1 content

The resistance of Solanum lycopersicum photosynthetic apparatus to high-intensity blue light is determined mainly by the cryptochrome 1 content

RED light promotes flavonoid and phenolic accumulation in Cichorium spp. callus culture as anti-candida agent

Chicory species, particularly Cichorium endive Supp. Pumillum, also, known as Egyptian chicory, are globally recognized for their rich content of bioactive secondary metabolites such as flavonoids and phenolics. These metabolites are highly valued for their pharmaceutical, dietary, and commercial applications. Light exposure, particularly through red and blue wavelengths, is a potent natural elicitor that influences the biosynthesis of secondary metabolites and impacts plant morphology. This study investigates the effects of red and blue LED light exposure on the callus culture of Egyptian chicory (Cichorium endive Supp. Pumillum), with the aim of enhancing flavonoid accumulation for potential use as an anti-Candida agent. Callus cultures of Cichorium intybus, Cichorium endive Supp. Pumillum, and Taraxacum officinale (Italian chicory) were grown on MS media supplemented with 4 mg/L 2iP and 0.5 mg/L NAA for 4 weeks. The cultures were then exposed to 12 days of red and blue LED light. After extraction using liquid nitrogen and methanol, the resulting callus extracts were tested against Candida albicans NRRL477 at various concentrations (1/8, 1/4, and 1/2 MIC) for 20 to 120 min. The antifungal activity was assessed by determining the effects on acid-soluble phosphorus, total lipids, and soluble proteins in the Candida cells. Our results demonstrate that the red LED light-exposed Cichorium endive Supp. Pumillum callus extract exhibited the most potent antifungal activity, significantly inhibiting the growth of Candida species compared to blue light and control treatments. Notably, the red light-treated callus culture accumulated higher concentrations of flavonoids and phenolic compounds, which contributed to its effectiveness as an anti-Candida agent. These findings suggest that LED red light elicitation is an effective method for enhancing the production of bioactive compounds in Egyptian chicory, offering potential for its use in natural antifungal therapies. Future research will explore the mechanistic pathways of flavonoid accumulation under different light conditions and investigate the broader applications of this elicitation technique for other medicinal plants.

Long Persistent Luminescence in Cu2+-Doped SrGa2Ge2O8 for Information Storage and Encryption.

Information storage and encryption are the key technologies for modern information transmission. However, most optical information storage technologies based on long persistent luminescent (PersL) only have one fixed response mode, which is easy to imitate, limiting their security in advanced information storage and encryption applications. Besides, the cost of rare earth-doped PersL materials restricts their wide application. Therefore, exploring non-rare earth-doped multimode PersL phosphors is an urgent and important topic. In this work, a novel SrGa2Ge2O8:Cu2+ (SGGO:Cu2+) phosphor with yellow-green PersL at 535 nm and near-infrared emission excited by ultraviolet light is designed. Furthermore, the two luminescence peaks of SGGO:0.007Cu2+ exhibit discriminable thermal quenching characteristics. Prominently, an outstanding photochromic performance from white to gray within 60 s under 254 nm light is found. The phosphor also has good bleaching and recovery ability under the irradiation of 450 nm blue light or heating treatment. Finally, the yellow-green PersL combined with thermochromism and reversible white-to-gray photochromism provides a promising multimode luminescent material, demonstrating the potential for multimode optical information storage and encryption applications.

Microwave Sensor with Light-Assisted Enhancement Based on Ti3C2Tx MXene: Toward ppb-Level NO2 Detection Limits.

Chemiresistive sensors are currently the most popular gas sensors, and metal semiconductor oxides are often used as sensitive materials (SMs). However, their high operating temperature means that more energy is required to maintain normal operation of the SM, resulting in an increase in power consumption of the entire sensing system. In order to solve this problem, a microwave gas sensor embedded with multilayer Ti3C2Tx MXene and split ring resonator (SRR) for nitrogen dioxide (NO2) detection was reported in this work. The sensor takes advantage of the weak coupling between the two SRRs to achieve a highly concentrated electric field and high Q-factor, in which the weak coupling region serves as the sensitive region to avoid damage to the resonator structure caused by the excessive conductivity of Ti3C2Tx. The sensor has good selectivity, a lower detection limit of 2 ppb, with an average detection sensitivity of 98.66 mdB ppm-1 in the range of 2-10,000 ppb at room temperature. Additionally, the effect of different lighting source to the sensor performance is investigated, and the sensor reached the best response (1.54 dB) under blue light. Finally, the mechanism of the enhanced sensitivity is discussed in detail based on the results of simulations and tests. The sensor circuit designed in this work provides a new approach for MGSs and for the first time introduces the photocatalytic pathway into microwave sensors, which will contribute to the optimization of microwave gas sensors in the future.

Sunlight promotes aboveground carbon loss by producing polysaccharides from litter decomposition in a temperate forest

Photodegradation is considered as a universal contributing factor to litter decomposition and carbon (C) cycling within the Earth’s biomes. Identifying how solar radiation modifies the molecular structure of litter is essential to understand the mechanism controlling its decomposition and reaction to shifts in climatic conditions and land-use. In this study, we performed a spectral-attenuation experiment following litter decomposition in an understory and gap of a temperate deciduous forest. We found that short-wavelength visible light, especially blue light, was the main factor driving variation in litter molecular structure of Fagus crenata Blume, Quercus crispula Blume, Acer carpinifolium Siebold & Zuccarini and Betula platyphylla Sukaczev, explaining respectively 56.5%, 19.4%, 66.3%, and 16.7% of variation in its chemical composition. However, the variation also depended on canopy openness: Only in the forest gap was lignin aromatic C negatively associated with C-oxygen (C–O) bonding in polysaccharides receiving treatments containing blue light of the full spectrum of solar radiation. Regardless of species, the decomposition index of litter that explained changes in mass and lignin loss was driven by the relative content of C–O stretching in polysaccharides and lignin aromatic C. The results suggest that the availability of readily degradable polysaccharides produced by the reduction in lignin aromatic C most plausibly explains the rate of litter photodegradation. Photo-products of photodegradation might augment the C pool destabilized by the input of readily degradable organic compounds (i.e., polysaccharides).