Multi-View Graph Contrastive Learning via Adaptive Channel Optimization for Depression Detection in EEG Signals.

Automated detection of depression using Electroencephalogram (EEG) signals has become a promising application in advanced bioinformatics technology. Although current methods have achieved high detection performance, several challenges still need to be addressed: (1) Previous studies do not consider data redundancy when modeling multi-channel EEG signals, resulting in some unrecognized noise channels remaining. (2) Most works focus on the functional connection of EEG signals, ignoring their spatial proximity. The spatial topological structure of EEG signals has not been fully utilized to capture more fine-grained features. (3) Prior depression detection models fail to provide interpretability. To address these challenges, this paper proposes a new model, Multi-view Graph Contrastive Learning via Adaptive Channel Optimization (MGCL-ACO) for depression detection in EEG signals. Specifically, the proposed model first selects the critical channels by maximizing the mutual information between tracks and labels of EEG signals to eliminate data redundancy. Then, the MGCL-ACO model builds two similarity metric views based on functional connectivity and spatial proximity. MGCL-ACO constructs the feature extraction module by graph convolutions and contrastive learning to capture more fine-grained features of different perspectives. Finally, our model provides interpretability by visualizing a brain map related to the significance scores of the selected channels. Extensive experiments have been performed on public datasets, and the results show that our proposed model outperforms the most advanced baselines. Our proposed model not only provides a promising approach for automated depression detection using optimal EEG signals but also has the potential to improve the accuracy and interpretability of depression diagnosis in clinical practice.

Effects of Environmental and Non-Environmental Factors on Dynamic Photosynthetic Carbon Assimilation in Leaves under Changing Light.

Major research on photosynthesis has been carried out under steady light. However, in the natural environment, steady light is rare, and light intensity is always changing. Changing light affects (usually reduces) photosynthetic carbon assimilation and causes decreases in biomass and yield. Ecologists first observed the importance of changing light for plant growth in the understory; other researchers noticed that changing light in the crop canopy also seriously affects yield. Here, we review the effects of environmental and non-environmental factors on dynamic photosynthetic carbon assimilation under changing light in higher plants. In general, dynamic photosynthesis is more sensitive to environmental and non-environmental factors than steady photosynthesis, and dynamic photosynthesis is more diverse than steady photosynthesis. Finally, we discuss the challenges of photosynthetic research under changing light.

Maize (Zea mays L.) planted at higher density utilizes dynamic light more efficiently.

In nature, plants are exposed to a dynamic light environment. Fluctuations in light decreased the photosynthetic light utilization efficiency (PLUE) of leaves, and much more severely in C4 species than in C3 species. However, little is known about the plasticity of PLUE under dynamic light in C4 species. Present study focused on the influence of planting density to the photosynthesis under dynamic light in maize (Zea mays L.), a most important C4 crop. In addition, the molecular mechanism behind photosynthetic adaptation to planting density were also explored by quantitative proteomics analysis. Results revealed that as planting density increases, maize leaves receive less light that fluctuates more. The maize planted at high density (HD) improved the PLUE under dynamic light, especially in the middle and later growth stages. Quantitative proteomics analysis showed that the transfer of nitrogen from Rubisco to RuBP regeneration and C4 pathway related enzymes contributes to the photosynthetic adaptation to lower and more fluctuating light environment in HD maize. This study provides potential ways to further improve the light energy utilization efficiency of maize in HD.

CORP: Sources and degrees of variability in whole animal intermittent hypoxia experiments.

Chamber exposures are commonly used to evaluate the physiological and pathophysiological consequences of intermittent hypoxia in animal models. Researchers in this field use both commercial and custom-built chambers in their experiments. The purpose of this Cores of Reproducibility in Physiology paper is to demonstrate potential sources of variability in these systems that researchers should consider. Evaluating the relationship between arterial oxygen saturation and inspired oxygen concentration, we found that there are important sex-dependent differences in the commonly used C57BL6/J mouse model. The time delay of the oxygen sensor that provides feedback to the system during the ramp-down and ramp-up phases was different, limiting the number of cycles per hour that can be conducted and the overall stability of the oxygen concentration. The time to reach the hypoxic and normoxic hold stages, and the overall oxygen concentration, were impacted by the cycle number. These variables were further impacted by whether there are animals present in the chamber, highlighting the importance of verifying the cycling frequency with animals in the chamber. At ≤14 cycles/h, instability in the chamber oxygen concentration did not impact arterial oxygen saturation but may be important at higher cycle numbers. Taken together, these data demonstrate the important sources of variability that justify reporting and verifying the target oxygen concentration, cycling frequency, and arterial oxygen concentration, particularly when comparing different animal models and chamber configurations.NEW & NOTEWORTHY Intermittent hypoxia exposures are commonly used in physiology and many investigators use chamber systems to perform these studies. Because of the variety of chamber systems and protocols used, it is important to understand the sources of variability in intermittent hypoxia experiments that can impact reproducibility. We demonstrate sources of variability that come from the animal model, the intermittent hypoxia protocol, and the chamber system that can impact reproducibility.

Has breeding altered the light environment, photosynthetic apparatus, and photosynthetic capacity of wheat leaves?

Whether photosynthesis has improved with increasing yield in major crops remains controversial. Research in this area has often neglected to account for differences in light intensity experienced by cultivars released in different years. Light intensity is expected to be positively associated with photosynthetic capacity and the resistance of the photosynthetic apparatus to high light but negatively associated with light-utilization efficiency under low light. Here, we analyzed the light environment, photosynthetic activity, and protein components of leaves of 26 winter wheat cultivars released during the past 60 years in China. Over time, light levels on flag leaves significantly decreased due to architectural changes, but photosynthetic rates under high or low light and the resistance of the photosynthetic apparatus to high light remained steady, contrary to expectations. We propose that the difference between the actual and expected trends is due to breeding. Specifically, breeding has optimized photosynthetic performance under high light rather than low light. Moreover, breeding selectivity altered the stoichiometry of several proteins related to dynamic photosynthesis, canopy light distribution, and photoprotection. These results indicate that breeding has significantly altered the photosynthetic mechanism in wheat and its response to the light environment. These changes likely have helped increase wheat yields.

Wheat embryo globulin nutrients ameliorate d-galactose and aluminum chloride-induced cognitive impairment in rats.

Wheat embryo globulin nutrient (WEGN), with wheat embryo globulin (WEG) as the main functional component, is a nutritional combination that specifically targets memory impairment. In this study, we explored the protective role of WEGN on Alzheimer's disease (AD)-triggered cognitive impairment, neuronal injury, oxidative stress, and acetylcholine system disorder. Specifically, we established an AD model via administration of d-galactose (d-gal) and Aluminum chloride (AlCl3) for 70 days, then on the 36th day, administered animals in the donepezil and WEGN (300, 600, and 900 mg/kg) groups with drugs by gavage for 35 days. Learning and memory ability of the treated rats was tested using the Morris water maze (MWM) and novel object recognition (NOR) test, while pathological changes and neuronal death in their hippocampus CA1 were detected via HE staining and Nissl staining. Moreover, we determined antioxidant enzymes by measuring levels of superoxide dismutase (SOD), malondialdehyde (MDA), and glutathione peroxidase (GSH-Px) in serum, cortex, and hippocampus, whereas changes in the acetylcholine system were determined by evaluating choline acetyltransferase (ChAT), and acetylcholinesterase (AChE) activities, as well as choline acetylcholine (Ach) content. Results revealed that rats in the WEGN group exhibited significantly lower escape latency, as well as a significantly higher number of targeted crossings and longer residence times in the target quadrant, relative to those in the model group. Notably, rats in the WEGN group spent more time exploring new objects and exhibited lower damage to their hippocampus neuron, had improved learning and memory activity, as well as reversed histological alterations, relative to those in the model group. Meanwhile, biochemical examinations revealed that rats in the WEGN group had significantly lower MDA levels and AChE activities, but significantly higher GSH, SOD, and ChAT activities, as well as Ach content, relative to those in the model group. Overall, these findings indicate that WEGN exerts protective effects on cognitive impairment, neuronal damage, oxidative stress, and choline function in AD rats treated by d-gal/AlCl3.

Counterion Optimization Dramatically Improves Selectivity for Phosphopeptides and Glycopeptides in Electrostatic Repulsion-Hydrophilic Interaction Chromatography.

A well-hydrated counterion can selectively and dramatically increase retention of a charged analyte in hydrophilic interaction chromatography. The effect is enhanced if the column is charged, as in electrostatic repulsion-hydrophilic interaction chromatography (ERLIC). This combination was exploited in proteomics for the isolation of peptides with certain post-translational modifications (PTMs). The best salt additive examined was magnesium trifluoroacetate. The well-hydrated Mg+2 ion promoted retention of peptides with functional groups that retained negative charge at low pH, while the poorly hydrated trifluoroacetate counterion tuned down the retention due to the basic residues. The result was an enhancement in selectivity ranging from 6- to 66-fold. These conditions were applied to a tryptic digest of mouse cortex. Gradient elution produced fractions enriched in peptides with phosphate, mannose-6-phosphate, and N- and O-linked glycans. The numbers of such peptides identified either equaled or exceeded the numbers afforded by the best alternative methods. This method is a productive and convenient way to isolate peptides simultaneously that contain a number of different PTMs, facilitating study of proteins with "crosstalk" modifications. The fractions from the ERLIC column were desalted prior to C-18-reversed phase liquid chromatography-tandem mass spectrometry analysis. Between 47-100% of the peptides with more than one phosphate or sialyl residue or with a mannose-6 phosphate group were not retained by a C-18 cartridge but were retained by a cartridge of porous graphitic carbon. This finding implies that the abundance of such peptides may have been significantly underestimated in some past studies.

The severe toxicity of CuO nanoparticles to the photosynthesis of the prokaryotic algae Arthrospira sp.

This research first verified that prokaryotic algae are more sensitive to toxicity of CuO nanoparticles (CuO NPs) than eukaryotic algae and that CuO NPs damaged photosynthesis of prokaryotic algae (Arthrospira sp.) but had no effect on respiration. The Cu2+ released by CuO NPs caused a bending deformation of the thylakoid, which was an important cause of the decline in photosynthetic capacity. In addition, the D1 protein was the most susceptible site to CuO NPs. The degradation of D1 protein reduced photosynthetic electron transport, which enhanced the excess excitation energy to cause the accumulation of reactive oxygen species (ROS) to further result in oxidative stress on algae. Dissolved organic matter (DOM) increased the toxicity of CuO NPs to photosynthesis of Arthrospira sp. The damage of photosynthesis caused by CuO NPs is an important reason why CuO NPs have a serious toxicity to algae.

Direct energy transfer from photosystem II to photosystem I confers winter sustainability in Scots Pine.

Evergreen conifers in boreal forests can survive extremely cold (freezing) temperatures during long dark winter and fully recover during summer. A phenomenon called "sustained quenching" putatively provides photoprotection and enables their survival, but its precise molecular and physiological mechanisms are not understood. To unveil them, here we have analyzed seasonal adjustment of the photosynthetic machinery of Scots pine (Pinus sylvestris) trees by monitoring multi-year changes in weather, chlorophyll fluorescence, chloroplast ultrastructure, and changes in pigment-protein composition. Analysis of Photosystem II and Photosystem I performance parameters indicate that highly dynamic structural and functional seasonal rearrangements of the photosynthetic apparatus occur. Although several mechanisms might contribute to 'sustained quenching' of winter/early spring pine needles, time-resolved fluorescence analysis shows that extreme down-regulation of photosystem II activity along with direct energy transfer from photosystem II to photosystem I play a major role. This mechanism is enabled by extensive thylakoid destacking allowing for the mixing of PSII with PSI complexes. These two linked phenomena play crucial roles in winter acclimation and protection.

Dynamic light caused less photosynthetic suppression, rather than more, under nitrogen deficit conditions than under sufficient nitrogen supply conditions in soybean.

BACKGROUND: Plants are always exposed to dynamic light. The photosynthetic light use efficiency of leaves is lower in dynamic light than in uniform irradiance. Research on the influence of environmental factors on dynamic photosynthesis is very limited. Nitrogen is critical for plants, especially for photosynthesis. Low nitrogen (LN) decreases ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) and thus limits photosynthesis. The decrease in Rubisco also delays photosynthetic induction in LN leaves; therefore, we hypothesized that the difference of photosynthetic CO2 fixation between uniform and dynamic light will be greater in LN leaves compared to leaves with sufficient nitrogen supply. RESULTS: To test this hypothesis, soybean plants were grown under low or high nitrogen (HN), and the photosynthetic gas exchange, enzyme activity and protein amount in leaves were measured under uniform and dynamic light. Unexpectedly, dynamic light caused less photosynthetic suppression, rather than more, in LN leaves than in HN leaves. The underlying mechanism was also clarified. Short low-light (LL) intervals did not affect Rubisco activity but clearly deactivated fructose-1,6-bisphosphatase (FBPase) and sedoheptulose-1,7-bisphosphatase (SBPase), indicating that photosynthetic induction after a LL interval depends on the reactivation of FBPase and SBPase rather than Rubisco. In LN leaves, the amount of Rubisco decreased more than FBPase and SBPase, so FBPase and SBPase were present in relative excess. A lower fraction of FBPase and SBPase needs to be activated in LN leaves for photosynthesis recovery during the high-light phase of dynamic light. Therefore, photosynthetic recovery is faster in LN leaves than in HN leaves, which relieves the photosynthetic suppression caused by dynamic light in LN leaves. CONCLUSIONS: Contrary to our expectations, dynamic light caused less photosynthetic suppression, rather than more, in LN leaves than in HN leaves of soybean. This is the first report of a stress condition alleviating the photosynthetic suppression caused by dynamic light.

Photoprotection by mitochondrial alternative pathway is enhanced at heat but disabled at chilling.

The mitochondrial alternative pathway (AP) represents an important photoprotective mechanism for the chloroplast, but the temperature sensitivity of its photoprotective role is unknown. In this study, using the aox1a Arabidopsis mutant, the photoprotective role of the AP was verified under various temperatures, and the mechanism underlying the temperature sensitivity of the AP's photoprotective role was clarified. It was observed that the photoprotective role of the AP increased with rising temperature but was absent at low temperature. The photoprotective role of the AP was severely reduced under non-photorespiratory conditions. Disturbance of the AP inhibited the conversion of glycine to serine in mitochondria, which may restrain upstream photorespiratory metabolism and aggravate photoinhibition. With rising temperatures, photorespiration accelerated and the restraint of photorespiration caused by disturbance of the AP also increased, determining the temperature sensitivity of the AP's photoprotective role. We also verified that not only the AP but also the cytochrome pathway in mitochondria contributes to photoprotection by maintaining photorespiration.

Salt adaptability in a halophytic soybean (Glycine soja) involves photosystems coordination.

BACKGROUND: Glycine soja is a halophytic soybean native to saline soil in Yellow River Delta, China. Photosystem I (PSI) performance and the interaction between photosystem II (PSII) and PSI remain unclear in Glycine soja under salt stress. This study aimed to explore salt adaptability in Glycine soja in terms of photosystems coordination. RESULTS: Potted Glycine soja was exposed to 300 mM NaCl for 9 days with a cultivated soybean, Glycine max, as control. Under salt stress, the maximal photochemical efficiency of PSII (Fv/Fm) and PSI (△MR/MR0) were significantly decreased with the loss of PSI and PSII reaction center proteins in Glycine max, and greater PSI vulnerability was suggested by earlier decrease in △MR/MR0 than Fv/Fm and depressed PSI oxidation in modulated 820 nm reflection transients. Inversely, PSI stability was defined in Glycine soja, as △MR/MR0 and PSI reaction center protein abundance were not affected by salt stress. Consistently, chloroplast ultrastructure and leaf lipid peroxidation were not affected in Glycine soja under salt stress. Inhibition on electron flow at PSII acceptor side helped protect PSI by restricting electron flow to PSI and seemed as a positive response in Glycine soja due to its rapid recovery after salt stress. Reciprocally, PSI stability aided in preventing PSII photoinhibition, as the simulated feedback inhibition by PSI inactivation induced great decrease in Fv/Fm under salt stress. In contrast, PSI inactivation elevated PSII excitation pressure through inhibition on PSII acceptor side and accelerated PSII photoinhibition in Glycine max, according to the positive and negative correlation of △MR/MR0 with efficiency that an electron moves beyond primary quinone and PSII excitation pressure respectively. CONCLUSION: Therefore, photosystems coordination depending on PSI stability and rapid response of PSII acceptor side contributed to defending salt-induced oxidative stress on photosynthetic apparatus in Glycine soja. Photosystems interaction should be considered as one of the salt adaptable mechanisms in this halophytic soybean.

Comparison of toxicological effects of oxybenzone, avobenzone, octocrylene, and octinoxate sunscreen ingredients on cucumber plants (Cucumis sativus L.).

Oxybenzone (OBZ), avobenzone (AVB), octocrylene (OCR) and octinoxate (OMC) are ultraviolet (UV) filters commonly added to chemical sunscreens. These UV filters are known to widely contaminate the environment through a variety of anthropogenic sources, including sewage discharge. However, systematic studies of the damage caused by these four UV filters and their toxicopathological differences in a variety of plant species are lacking. In this study, we demonstrated that irrigation with water containing these four UV filters could significantly inhibit the aboveground growth of cucumber plant. All of the UV filters decreased photosynthesis through nonstomatal factors but via different inhibitory mechanisms. Only OBZ inhibited photosynthesis by directly inhibiting photosynthetic electron transport, while the other three (AVB, OCR, and OMC) inhibited photosynthesis by inhibiting the Calvin-Benson cycle. Additionally, these four UV filters also decreased plant respiration under long-term treatment. Photosynthesis and respiration inhibition led to the over production of reactive oxygen species (ROS) and the formation of lipid peroxidation damage products, which further damaged the structure and function of plant cells, causing secondary pathologies and potentially leading to reduced crop yields. The study also demonstrated that these four UV filters caused different degrees of phototoxic damage to cucumber plants. On the basis of comprehensive evaluation, we speculated that the order of the four UV filters in terms of plant damage was OBZ > AVB > OMC > OCR. Because of the severe damaging effects of these UV filters on plant growth, the application of contaminated biosolids/reclaimed water in agriculture reduces agricultural production and may damage ecosystems. The results of this study can advance recognition of the hazards associated with environmental and agricultural pollution via UV filters and encourage consumers and the industry to limit or reduce the application of cosmetics and over-the-counter drugs containing these substances.

The toxicological effects of oxybenzone, an active ingredient in suncream personal care products, on prokaryotic alga Arthrospira sp. and eukaryotic alga Chlorella sp.

Oxybenzone (OBZ; benzophenone-3, CAS# 131-57-7) is a known pollutant of aquatic and marine ecosystems, and is an ingredient in over 3000 personal care products, as well as many types of plastics. The aim of this study is to explore the different toxicities of OBZ on an eukaryotic (Chlorella sp.) and a prokaryotic algae (Arthrospira sp.). OBZ is a photo-toxicant, with all observed toxicities more sever in the light than in the dark. Cell growth and chlorophyll inhibition were positively correlated with increasing OBZ concentrations over time. Twenty days treatment with OBZ, as low as 22.8 ng L-1, significantly inhibited the growth and chlorophyll synthesis of both algae. Both algae were noticeably photo-bleached after 7 days of exposure to OBZ concentrations higher than 2.28 mg L-1. Relatively low OBZ concentrations (0.228 mg L-1) statistically constrained photosynthetic and respiratory rates via directly inhibiting photosynthetic electron transport (PET) and respiration electron transport (RET) mechanisms, resulting in over production of reactive oxygen species (ROS). Transmission and scanning electron microscopy showed that the photosynthetic and respiratory membrane structures were damaged by OBZ exposure in both algae. Additionally, PET inhibition suppressed ATP production for CO2 assimilation via the Calvin-Benson cycle, further limiting synthesis of other biomacromolecules. RET restriction limited ATP generation, restricting the energy supply used for various life activities in the cell. These processes further impacted on photosynthesis, respiration and algal growth, representing secondary OBZ-induced algal damages. The data contained herein, as well as other studies, supports the argument that global pelagic and aquatic phytoplankton could be negatively influenced by OBZ pollution.

Investigation on failure behavior of collapse column in China's coal mine based on discontinuous deformation numerical method.

Karst collapse column is a serious geological disaster in China's coal mines. There are various karst collapse columns in coal mine areas, such as Huainan, Huaibei, Xingtai, Lu'an. And they have seriously affected mining safety and geological environment. The present research is focused on analyzing subsidence mechanism and dynamic collapse process. Based on mechanical analysis of thin plate theory, a detailed model of collapse column slipping and bending fracture is constructed to gather the critical conditions of the collapse column roof. The sensitivity parameters analysis shows that both the radius and roof thickness of cave have a great influence on the sliding instability and bending fracture. Meanwhile, the buried depth also affects bending failure. The discontinuous deformation analysis (DDA) method is used to simulate and analyze the collapse process. The numerical results indicate that the stability of inverted funnel collapse column is dominated by the bending stress of roof strata. The movement of columnar collapse column is mainly caused by sliding instability. However, the funnel collapse column is relatively stable, and does not change in the same condition. The displacement field analysis shows that the collapse range of inverted funnel collapse column is obviously larger than that of columnar collapse column, in which its maximum displacement is approximately 1.5 times that of the columnar collapse column. There is no large area collapse on the upper part of the funnel collapse column, and the block system is relatively stable. The principal stress field analysis proves the above results.

Stress⁻Strain Properties and Gas Permeability Evolution of Hybrid Fiber Engineered Cementitious Composites in the Process of Compression.

Polyvinyl alcohol (PVA)-steel hybrid fiber reinforced engineered cementitious composites (ECC) characterized by optimal combination of high strength and high ductility were developed recently. These composites exhibit even tighter crack width than normal ECC, showing great potential for lower permeability in cracked state, and consequently improving the durability of ECC structures. In addition, the wide variety of promising applications in underground or hydraulic structures calls for knowledge on the mechanical behavior and corresponding permeability properties of strained ECC under multiaxial stress, as they are essential for structural analysis and durability design. Experimental investigations into the compressive properties and the in-situ gas permeability of PVA-steel hybrid fiber ECC were performed in this study, with special focus on the impact of additional steel fiber content and confining pressure. The test results show that the presence of a low confinement level allows ECC to attain a substantial improvement on compressive behavior but impairs the enhancement efficiency of additional steel fiber. The permeability evolution of strained ECC corresponds to the variation of radial strains, both of which experience little change below the threshold stress but a rapid increase beyond the peak axial strain. Apart from exhibiting low permeability at relatively small strains in the pre-peak stage, ECC can also exhibit low permeability at higher levels of compressive strain up to 2.0%. However, unlike the case in tensile loading, impermeability of cracked ECC in compression would be weakened by additional steel fibers, especially in the post-peak stage. The present research is expected to provide insight into performance-based durability design of structures made of or strengthened with ECC.

Slower development of PSI activity limits photosynthesis during Euonymus japonicus leaf development.

This study primarily explored the limiting factor for photosynthesis during the development of Euonymus japonicus leaves. The analysis of the chlorophyll fluorescence transient, pulse-modulated fluorescence, 820-nm reflection, and expression of core proteins for photosystems demonstrated that photosystem II (PSII) activity developed more rapidly than did photosystem I (PSI) activity. The slower development of the PSI activity restricted linear and cyclic electron transport and thus inhibited the production of ATP and NADPH, which inhibits the activation of Rubisco, resulting in low activity of carboxylation efficiency. The application of exogenous NADPH (50 µM) and ATP (100 µM) to leaves remarkably increased the Pn and CE in the youngest leaf but not in the fully expanded leaf, which indicated that an inadequate supply of the assimilatory power significantly inhibited CE and Pn. We concluded that the slower development of the PSI activity was one of the most important limiting factors for photosynthesis during the development of E. japonicus leaves.