Changes In Light Intensity Research Articles

Self-calibrated pulse oximetry algorithm based on photon pathlength change and the application in human freedivers.

Pulse oximetry estimates the arterial oxygen saturation of hemoglobin () based on relative changes in light intensity at the cardiac frequency. Commercial pulse oximeters require empirical calibration on healthy volunteers, resulting in limited accuracy at low oxygen levels. An accurate, self-calibrated method for estimating is needed to improve patient monitoring and diagnosis. Given the challenges of calibration at low levels, we pursued the creation of a self-calibrated algorithm that can effectively estimate across its full range. Our primary objective was to design and validate our calibration-free method using data collected from human subjects. We developed an algorithm based on diffuse optical spectroscopy measurements of cardiac pulses and the modified Beer-Lambert law (mBLL). Recognizing that the photon mean pathlength () varies with related absorption changes, our algorithm aligns/fits the normalized (across wavelengths) obtained from optical measurements with its analytical representation. We tested the algorithm with human freedivers performing breath-hold dives. A continuous-wave near-infrared spectroscopy probe was attached to their foreheads, and an arterial cannula was inserted in the radial artery to collect arterial blood samples at different stages of the dive. These samples provided ground-truth via a blood gas analyzer, enabling us to evaluate the accuracy of estimation derived from the NIRS measurement using our self-calibrated algorithm. The self-calibrated algorithm significantly outperformed the conventional method (mBLL with a constant ratio) for estimation through the diving period. Analyzing 23 ground-truth data points ranging from 41% to 100%, the average absolute difference between the estimated and the ground truth is for our algorithm, significantly lower than the observed with the conventional approach. By factoring in the variations in the spectral shape of relative to , our self-calibrated algorithm enables accurate estimation, even in subjects with low levels.

High Light Intensity and CO2 Enrichment Synergistically Mitigated the Stress Caused by Low Salinity in Pyropia yezoensis

Macroalgae, playing a crucial role in coastal marine ecosystems, are subject to multiple environmental challenges due to tidal and seasonal alterations. In this work, we investigated the physiological responses of Pyropia yezoensis to ocean acidification (ambient CO2 (AC: 400 μatm) and elevated CO2 (HC: 1000 μatm)) under changing salinity (20, 30 psu) and light intensities (50, 100 μmol photons m−2 s−1) by measuring the growth, pigment content, chlorophyll fluorescence, and soluble sugar content. The key results are the following: (1) P. yezoensis exhibited better growth under normal salinity (30 psu) compared to hyposaline conditions (20 psu). (2) Intermediate light intensity increased phycoerythrin content, ultimately enhancing thalli growth without significant changes to the contents of chlorophyll a and carotenoids. (3) Ocean acidification alleviated hyposaline stress by enhancing pigment production in P. yezoensis only at a salinity of 20 psu, highlighting the complex interplay of these environmental factors. These findings indicate that higher light intensities and elevated pCO2 levels could mitigate the stress caused by low salinity.

An Optical Micro/Nano Fiber Sensor for Monitoring Respiration

In the field of clinical medicine, the real-time monitoring of carbon dioxide (CO2) gas exhaled by the human body is of great significance. At present, the detection devices on the market mainly work by sucking a small amount of gas from the nasal cavity into the detection device, and they present some problems such as overly long sampling tubes, easy blockage or distortion, and an abnormal gas dispersion. In this paper, a micro/nano optical fiber sensor that can directly detect respiration is proposed and is characterized by the relative change in CO2 concentration. The measurement is achieved by using the principle of high evanescent field absorption, and the operating band is 2.004 μm. The sensing effects of micro/nano fibers with different diameters are compared, and the experiment proves that a micro/nano fiber with a diameter of 1 μm can be measured. The light intensity change over 30 s was measured, and the breathing rate was 10–11 times/min. The sensor can achieve a rapid real-time response to CO2 gas detection and is small in size, low-cost, and easy to replace. It has a great application potential in clinical scenarios such as in gastrointestinal endoscopes that require real-time monitoring of human respiration.

Sensory evolution: A dazzling hack to cope with bright light in owls and whales

When exposed to sudden changes in light intensity, rod-dominated retinas of animals with highly sensitive dim-visionrisk critical damage. A new study finds that owls and deep-diving whales have evolved an identical photoprotection mechanism to delay toxic all-trans retinal release, a discovery with potential medical implications.

Buckling morphology of glassy nematic films with staggered director field

The photo-induced buckling of axially periodic glassy nematic films with alternating stripped director domains is explored by the Föppl-von Kármán plate theory along with a modified kinetics approach. The effects of domain widths on the critical light intensity as well as the buckling morphology are examined numerically. It is found that in most cases the buckled film forms regularly aligned dimples and protrusions, but shows large scale bending perpendicular to the periodic axis if the widths of the stripes are nearly the same. In addition, change in light intensity is shown to alter the wavenumber of the buckling pattern. These results are expected helpful to the design of shape-shifting structures with glassy nematic films.

Possible Contribution of Corticular Photosynthesis to Grapevine Winter Hardiness

Numerous studies show that photosynthesis in non-foliar tissues contributes to plant productivity. Here, we demonstrate that in chlorenchyma tissues of lignified branches of grape vines, photosynthetic activity is maintained during winter and provide evidence that corticular photosynthesis could contribute to the plant’s freeze tolerance. In a collection of grape varieties that varied noticeably in freeze tolerance, a positive correlation between the maximum quantum yield of photosystem II in the wintering vines and the ability to survive harsh winter temperatures was observed. A more detailed comparison of two grapevine varieties differing in freeze tolerance showed that the vines of the more tolerant variety have more abundant corticular chlorenchyma with chloroplasts containing a better developed network of photosynthetic membranes, characterized by a higher photosynthetic pigments content, higher efficiency of both photosystems, and higher mobility of antennae complexes under the changing light intensity. In addition, we found that freezing temperatures induced more damage in vine samples when they were preliminarily treated with a specific inhibitor of photosynthetic electron transfer. The data obtained could be useful in the generation of freeze-tolerant grape varieties.

Aphid Recognition and Counting Based on an Improved YOLOv5 Algorithm in a Climate Chamber Environment.

Due to changes in light intensity, varying degrees of aphid aggregation, and small scales in the climate chamber environment, accurately identifying and counting aphids remains a challenge. In this paper, an improved YOLOv5 aphid detection model based on CNN is proposed to address aphid recognition and counting. First, to reduce the overfitting problem of insufficient data, the proposed YOLOv5 model uses an image enhancement method combining Mosaic and GridMask to expand the aphid dataset. Second, a convolutional block attention mechanism (CBAM) is proposed in the backbone layer to improve the recognition accuracy of aphid small targets. Subsequently, the feature fusion method of bi-directional feature pyramid network (BiFPN) is employed to enhance the YOLOv5 neck, further improving the recognition accuracy and speed of aphids; in addition, a Transformer structure is introduced in front of the detection head to investigate the impact of aphid aggregation and light intensity on recognition accuracy. Experiments have shown that, through the fusion of the proposed methods, the model recognition accuracy and recall rate can reach 99.1%, the value mAP@0.5 can reach 99.3%, and the inference time can reach 9.4 ms, which is significantly better than other YOLO series networks. Moreover, it has strong robustness in actual recognition tasks and can provide a reference for pest prevention and control in climate chambers.

Seasonal variation of gross ecosystem productivity of periphyton in three post-mining lakes in the Czech Republic, Europe

We investigated the seasonal variation of gross ecosystem productivity (GEP) of periphyton biomass in three post-mining lakes in the Czech Republic. These lakes were established as part of recultivation efforts after coal mining activities and resulted in a unique series of anthropogenic oligotrophic lakes of gradual successional age. Periphyton is ubiquitous in aquatic habitats and performs numerous environmental functions such as nutrient cycling and self-purifying of aquatic ecosystems. Well-developed periphyton mat can be formed within a few weeks, so it can quickly become the dominant of littoral zone of newly established lakes. In studied post-mining lakes, the highly developed periphytic community covers the littoral zone of each lake to the depth of 2m (Bešta et al. 2022, Konopáčová et al. 2023) Fig. 1. We aimed to shed some new light on the processes controlling the dynamics of primary productivity in oligotrophic lakes. The accurate estimation of primary productivity is crucial for understanding the functioning of aquatic ecosystems, as primary productivity serves as the primary source of autochthonous carbon in these systems. In addition to phytoplankton, periphyton can significantly contribute to primary productivity in littoral zones, known for their high productivity and biodiversity. Conducting in situ measurements provides the most accurate means of inferring the metabolic activity of primary producers in littoral zones. We conducted detailed seasonal in-situ periphyton gross primary production (GPP) measurements in three post-mining lakes with different successional ages (Čapková et al. 2022). GPP and NPP of periphytic biomass were determined using direct in-situ measurement of O2 fluxes. O2 production and consumption were measured over 5 hours of in-situ light and dark gas-tight glass bottle incubation. Bottles were filled with the lake water from the corresponding depth, and a similar amount of periphytic biomass was enclosed Fig. 2. We used the Fibox3 fibre-optic oxygen meter coupled with a PSt3 oxygen sensor (PreSens, Regensburg, DE) to measure changes in O2 concentration. The O2 fluxes were normalized to periphytic biomass in each bottle (measured as total organic carbon). Data were corrected for O2 concentration changes in dark and light gas-tight bottles containing lake water without periphytic communities. This setup enabled us to monitor online oxygen flux, therefore, insights into metabolic activities. The primary productivity was measured in real-time, allowing us to capture the quantitative effect of various environmental drivers on periphyton productivity, i.e. phosphorus concentration and light intensity, as they are known to play significant roles in primary productivity. We showed that the primary production of periphyton mats exhibited seasonal variations, with higher productivity observed in spring compared to other seasons. This observation could be attributed to the occurrence of winter/spring upwelling events and vertical mixing, which resupply nutrients from the deeper strata. Furthermore, the physiological activity of periphyton was strongly influenced by the seasonal changes in light intensity, temperature, and nutrient concentration. We provided the first insight into the seasonal variation of primary productivity of the periphyton assemblage dominating the littoral zone of newly established post-mining lakes. We stress the importance of periphyton in aquatic ecosystems, particularly in anthropogenic oligotrophic lakes.

Using Dual Spatial Clustering Models for Urban Fringe Areas Extraction Based on Night-time Light Data: Comparison of NPP/VIIRS, Luojia 1-01, and NASA’s Black Marble

Night-time light data (NTL) have been extensively utilized to map urban fringe areas, but to date, there has not been a comprehensive evaluation of the existing spatial clustering methods for delineating the urban fringe using different types of night-time light data. Therefore, we first selected three popular sources of night-time light data (i.e., NPP/VIIRS, Luojia 1-01, and NASA’s Black Marble) to identify the urban fringe. The recognition of spatial mutations across the urban–rural gradient was conducted based on changes in night light intensity using a spatial continuous wavelet transform model. Then, we employed three representative dual spatial clustering approaches (i.e., MK-Means, DBSC, and DSC) for extracting urban fringe areas using different NTL. By using dual spatial clustering, the spatial patterns of the mutation points were effectively transformed into homogeneous spatially adjacent clusters, enabling the measurement of similarity between mutation points. Taking Nanjing city, one of China’s megacities, as the study area, we found that (1) Compared with the fragmented and concentrated results obtained from the Luojia 1-01, NASA’s Black Marble and NPP/VIIRS data can effectively capture the abrupt change of urban fringes with NTL variations; (2) DSC provided a reliable approach for accurately extracting urban fringe areas using NASA’s Black Marble data.

PGR5-LIKE PHOTOSYNTHETIC PHENOTYPE1A redox states alleviate photoinhibition during changes in light intensity.

Plants have evolved photosynthetic regulatory mechanisms to maintain homeostasis in response to light changes during diurnal transitions and those caused by passing clouds or by wind. One such adaptation directs photosynthetic electron flow to a cyclic pathway to alleviate excess energy surges. Here, we assign a function to regulatory cysteines of PGR5-like protein 1A (PGRL1A), a constituent of the PROTON GRADIENT REGULATION5 (PGR5)-dependent cyclic electron flow (CEF) pathway. During step increases from darkness to low light intensity in Arabidopsis (Arabidopsis thaliana), the intermolecular disulfide of the PGRL1A 59-kDa complex was reduced transiently within seconds to the 28-kDa form. In contrast, step increases from darkness to high light stimulated a stable, partially reduced redox state in PGRL1A. Mutations of 2 cysteines in PGRL1A, Cys82 and Cys183, resulted in a constitutively pseudo-reduced state. The mutant displayed higher proton motive force (PMF) and nonphotochemical quenching (NPQ) than the wild type (WT) and showed altered donor and acceptor dynamic flow around PSI. These changes were found to correspond with the redox state of PGRL1A. Continuous light regimes did not affect mutant growth compared to the WT. However, under fluctuating regimes of high light, the mutant showed better growth than the WT. In contrast, in fluctuating regimes of low light, the mutant displayed a growth penalty that can be attributed to constant stimulation of CEF under low light. Treatment with photosynthetic inhibitors indicated that PGRL1A redox state control depends on the penultimate Fd redox state. Our results showed that redox state changes in PGRL1A are crucial to optimize photosynthesis.

Production of Photosynthetic Pigments from Spirulina platensis Under Different Light Intensities

Photosynthetic pigments from microalgae have great potential biotechnological applications, as healthy food colorants and cosmetics. The production of photosynthetic pigments depends on many environmental conditions, mainly light intensity during the cultivation period. The present study aimed to determine the productivity of photosynthetic pigments in the biomass of S. platensis, including total chlorophylls, carotenoids, and phycocyanin, under different light intensities: 40 µmol m–2 s–1 (lower light intensity) and 70 µmol m–2 s–1 (higher light intensity). The results showed that S. platensis culture responds to changes in light intensity by changing the composition of photosynthetic pigments as an adaptive mechanism. The higher carotenoids content (69.69 ± 7.47 µg/g dw) was found under high light intensity, meanwhile, the higher chlorophyll (1495.47 ± 279.00 µg/g dw) and phycocyanin (4995.49 ± 576.52 µg/g dw) contents were observed under low light intensity. The highest productivity of photosynthetic pigments in S. platensis was shown by phycocyanin (318.86 ± 44.22 µg/L/day) and cholophylls (95.38 ± 19.35 µg/L/day) which were produced under low light intensity. Our results show that changes in light intensity can contribute to a stronger effect on the productivity of algal pigments for human health benefits and food colorants.

Highly sensitive and selective detection of nitrite using a fiber optofluidic laser.

Nitrite ion (NO2-) is a common contaminant that can significantly threaten human health and the environment. In this study, we demonstrate a chemical sensing platform to monitor the nitrite concentration using a fiber optofluidic laser (FOFL). An optical fiber, integrated into a microchannel, is used both as an optical micro-cavity and the sensing element. Rhodamine 6 G (Rh6G) in an aqueous micellar solution is used as the laser gain medium. The light intensity change of the lasing spectra is employed as an indicator for the NO2- ion concentration sensing. The lasing properties under different NO2- ion concentrations are experimentally and theoretically investigated to examine the sensing performance of the FOFL. The results show that the limit detection of the FOFL sensor is 0.54 µM, which is 2-order-of-magnitude lower than fluorescence measurement. The sensing mechanism of Rh6G for NO2- detection is studied by using density functional theory (DFT). The calculation results indicate that nitrite influences the electronic distribution of Rh6G based on the heavy atom effect, which leads to the fluorescence quenching of Rh6G in the excited state. In addition, the detection system exhibits favorable selectivity for NO2- ions.

Camera-based Non-contact Respiratory Rate Estimation

A non-contact-based system for estimating the respiration rate of individuals using a mobile phone camera is presented in this paper. Respiration rate is an important vital sign that indicates the number of breaths a person takes per minute and is commonly used in medical assessments. The method involves recording videos of the pit of the neck region using the mobile phone camera and analyzing the changes in light intensity within the video frames. By processing the obtained signals from the video frames, the system accurately estimates the respiration rate. The effectiveness of the proposed method and the estimated respiration rates are compared with rates obtained using two other methods: a spirometer, which is a device used to measure lung function and manual counting. The evaluation is conducted on a group of 34 participants who are instructed to breathe rapidly to simulate varying respiration rates. The results indicate that the presented method achieves an accuracy of over 80% compared with existing state-of-the-art methods. The standard deviation of ±3% suggests a relatively consistent performance across participants. The calculated error between the estimated respiration rates and the reference rates obtained from the spirometer and manual counting validates the reliability of the proposed approach. Additionally, the paper highlights the advantages of this system, including its cost-effectiveness and suitability for remote monitoring and mass screening. The non-contact nature of the method reduces the need for physical contact with patients, which could be especially beneficial in situations where hygiene and infection control are crucial. The paper also outlines plans for future work, which involve validating the method with larger sample sizes and exploring its potential applications in various clinical scenarios.

Valve gaping behaviour in the European oyster (Ostrea edulis) in response to changes in light intensity when combined with variations in salinity and seawater temperature

Valve gaping behaviour in bivalve molluscs controls the flow of water across gills that provides both food, and oxygen for respiration. Closure of the valves also provides protection from predators and poor-quality water conditions. Research presented here used a flow through seawater system with controlled changes in salinity and temperature, combined with continuous measurement of valve gape using Hall effect sensors, to study how changes in these variables affect the valve movements of the European oyster (Ostrea edulis) held under controlled long day-length conditions. A clear relationship between periods of reduced light intensity and maximum valve gape was recognised in preliminary studies and provided a benchmark against which to compare how changes in environmental conditions linked to climate change may alter the behaviour of these coastal marine bivalves. Oysters collected from the southwest coast of Norway in August 2022 were held for 72 h at full seawater salinity of 33.6 and a temperature of 15.8 ± 0.5 °C prior to exposure to a reduction in salinity down to 18.2 over a 3 h period. Oysters showed an initial reduction in valve gape width as salinity reached 31.4, with valve gape decreasing further as salinity fell to 28.8. All valves were fully closed at salinity 20.5. Oysters remained in this condition throughout the subsequent 21 h exposure period with salinity at 18.2. Thereafter salinity was increased in 3 steps. In the first step, salinity reached 24.2 over 2 h, and was held there over the following 22 h. All oysters commenced re-opening valves between salinity 22.8 and 24.2. When salinity was further increased to 27.3 over the subsequent 24 h, oysters returned to approximately their pre-exposure valve gape widths. When salinity 33.8 was delivered to the tanks there were 2 d during which maximum valve gape was significantly reduced, after which valve gape width returned to a pre-exposure condition. The predicted pattern of valve opening during reduced light intensity periods was maintained when seawater temperature was raised from 15.8 °C up to 20.1 °C in approximately 1 °C steps every 24 h. However, reduction of temperature from 20.1 °C in similar sized increments altered the expected patterns of behaviour. The results indicate that increasing occurrences of fluxes in salinity and temperature due to climate change have the potential to disrupt normal valve gaping behaviour in European oysters, creating an additional challenge to those they already face from invasive species and disease.

Deep learning-based multiscale CNN-based U network model for leaf disease diagnosis and segmentation of lesions in tomato

BackgroundThe advent of deep learning technologies has expanded the utilization of convolutional neural networks in diagnosing and segmenting plant leaf diseases. However, the segmentation of lesions, especially those with diverse sizes and shapes, often requires extensive pixel-level annotations. ObjectiveThis study aims to introduce a multiscale U-network for effective concurrent segmentation and diagnosis of tomato leaf lesions. MethodsOur model employs multi-scale residual modules to adapt dynamically to diseases that alter lesion size and shape. The Classifier and Bridge (CB) module is introduced to connect the disease feature extraction stage with the disease spot segmentation stage, providing crucial information about a specific lesion type. During the segmentation stage, the activation map of a specific class is deconvoluted using a combination of up-sampling and convolution. This deconvolution feature is fused with the low-level feature through a skip connection strategy. A limited number of pixel-level labels are used, and the binary cross-entropy loss function is applied for supervised training at each pixel point, directing the feature extraction network to focus on the lesion location. ResultsThe model was evaluated using an original test set and an interference test set simulating noise and light intensity changes. The multiscale U-network demonstrated an average pixel accuracy of approximately 99.2%, a resilience to brightness reduction by about 92.4%, and an ability to handle up to 0.98 salt and pepper noise at a rate of about 99.2%, showcasing its robustness against various image alterations. The GFLOPs for the proposed method was found to be approximately 3.13e+06, indicating its computational efficiency. ConclusionThe experimental results highlight the potential of the proposed multiscale U-network in effectively segmenting and identifying lesions in tomato leaf tissue. These findings suggest promising opportunities for applying this model in the broader field of agricultural disease management.

A single n-type semiconducting polymer-based photo-electrochemical transistor

Conjugated polymer films, which can conduct both ionic and electronic charges, are central to building soft electronic sensors and actuators. Despite the possible interplay between light absorption and the mixed conductivity of these materials in aqueous biological media, no single polymer film has been utilized to create a solar-switchable organic bioelectronic circuit that relies on a fully reversible and redox reaction-free potentiometric photodetection and current modulation. Here we demonstrate that the absorption of light by an electron and cation-transporting polymer film reversibly modulates its electrochemical potential and conductivity in an aqueous electrolyte, which is harnessed to design an n-type photo-electrochemical transistor (n-OPECT). By controlling the intensity of light incident on the n-type polymeric gate electrode, we generate transistor output characteristics that mimic the modulation of the polymeric channel current achieved through gate voltage control. The micron-scale n-OPECT exhibits a high signal-to-noise ratio and an excellent sensitivity to low light intensities. We demonstrate three direct applications of the n-OPECT, i.e., a photoplethysmogram recorder, a light-controlled inverter circuit, and a light-gated artificial synapse, underscoring the suitability of this platform for a myriad of biomedical applications that involve light intensity changes.

Daily Rhythmicity of Muscle-Related and Rhythm Genes Expression in Mackerel Tuna (Euthynnus affinis).

The aim of this study was to investigate the circadian rhythm of muscle-related gene expression in mackerel tuna under different weather conditions. The experiment was carried out under two weather conditions at four sampling times (6:00, 12:00, 18:00, and 24:00) to determine the expression of growth, function, and rhythm genes: white muscle rhythm genes were rhythmic on sunny and cloudy days, except for PER3 and RORA; all functional genes had daily rhythmicity. Red muscle had daily rhythmicity on both sunny and cloudy days; functional genes had daily rhythmicity except for MBNL. The expression levels of the rhythm gene PER1 were determined to be significantly different by independent t-test samples in white muscle at 6:00, 12:00, 18:00, and 24:00 under different weather conditions; the expression levels of the functional genes MBNL and MSTN were both significantly different. In the red muscle, the expression of the rhythm genes PER3, REVERBA, and BMAL1 was determined by independent t-test samples at 6:00, 12:00, 18:00, and 24:00 on cloudy and sunny days; the functional gene MBNL was significantly different. The present study showed that mackerel tuna muscle rhythm genes and functional genes varied significantly in expression levels depending on weather, time of day, and light intensity and that the expression levels of myogenic genes were closely related to clock gene expression. The fish were also able to adapt to changes in light intensity in different weather conditions through positive physiological regulation.

Visual disturbances in patients with Parkinson's Disease treated with oral medications or deep brain stimulation.

Ophthalmological symptoms are common in patients with Parkinson's Disease (PD) and can be evaluated by the Visual Impairment in Parkinson's Disease Questionnaire (VIPD-Q). This study aimed to assess the prevalence of ophthalmological symptoms in PD depending on the type of treatment used i.e. pharmacological or subthalamic nucleus deep brain stimulation (STN-DBS). We performed a cross-sectional study. The data was gathered from a VIPD-Q and from medical records. Patients with PD were divided into two groups based on the type of treatment - pharmacological (control group, CG) (39 patients) or STN-DBS (40 patients). The great majority of patients - 72 (91.1%) - experienced an ophthalmological symptom. The prevalence of three symptoms differed significantly between the groups. A burning sensation or a gritty feeling in the eyes occurred more often in patients in the STN-DBS group (40.0% vs. 15.4%; p = 0.015). On the other hand, the inability to read plain text on a coloured or grey background and problems with rapid changes of light intensity were more common in the CG group (38.5% vs. 15.0%, p = 0.018 and 28.2% vs. 10.0%, p = 0.039, respectively). The prevalence of ophthalmological symptoms in PD is high. Despite significant differences in the three symptoms, the overall prevalence of ophthalmological clinical features was similar in the evaluated groups.

GmPLP1 negatively regulates soybean resistance to high light stress by modulating photosynthetic capacity and reactive oxygen species accumulation in a blue light-dependent manner.

High light stress is an important factor limiting crop yield. Light receptors play an important role in the response to high light stress, but their mechanisms are still poorly understood. Here, we found that the abundance of GmPLP1, a positive blue light receptor protein, was significantly inhibited by high light stress and mainly responded to high blue light. GmPLP1 RNA-interference soybean lines exhibited higher light energy utilization ability and less light damage and reactive oxygen species (ROS) accumulation in leaves under high light stress, while the phenotype of GmPLP1:GmPLP1-Flag overexpression soybean showed the opposite characteristics. Then, we identified a protein-protein interaction between GmPLP1 and GmVTC2, and the intensity of this interaction was primarily affected by sensing the intensity of blue light. More importantly, overexpression of GmVTC2b improved soybean tolerance to high light stress by enhancing the ROS scavenging capability through increasing the biosynthesis of ascorbic acid. This regulation was significantly enhanced after interfering with a GmPLP1-interference fragment in GmVTC2b-ox soybean leaves, but was weakened when GmPLP1 was transiently overexpressed. These findings demonstrate that GmPLP1 regulates the photosynthetic capacity and ROS accumulation of soybean to adapt to changes in light intensity by sensing blue light. In summary, this study discovered a new mechanism through which GmPLP1 participates in high light stress in soybean, which has great significance for improving soybean yield and the adaptability of soybean to high light.

Performance improvement of white-light-driven resonant fiber optic gyroscope using four-frequency sawtooth wave modulation technology

In this study, a novel resonant fiber optic gyroscope (RFOG) that relies on four-frequency sawtooth wave modulation technology is proposed. This innovative approach is utilized to demodulate both the light intensity changes of the optical system and the half-wave voltage drift of the multi-functional integrated optical chip (MIOC). The principle of modulation is expounded, and a simulation model is established to evaluate the performance of the system. We conducted synchronous compensation of the bias drift, which is caused by the light intensity changes, and applied closed-loop control to MIOC modulation frequency-shift voltage, effectively reducing the scale factor error. As a result, the system achieved a bias instability (BI) of 0.0055°/h, with a 500 m-long fiber-optic ring resonator (FRR) of 6 cm diameter, at room temperature. Furthermore, the scale factor error was reduced by more than threefold in the temperature range of −40 °C to 70 °C. These results demonstrate the superior performance of the proposed RFOG and its potential for high-precision navigation and other applications.