Tea bud target detection is essential for mechanized selective harvesting. To address the challenges of low detection precision caused by the complex backgrounds of tea leaves, this paper introduces ...a novel model called Tea-YOLOv8s. First, multiple data augmentation techniques are employed to increase the amount of information in the images and improve their quality. Then, the Tea-YOLOv8s model combines deformable convolutions, attention mechanisms, and improved spatial pyramid pooling, thereby enhancing the model's ability to learn complex object invariance, reducing interference from irrelevant factors, and enabling multi-feature fusion, resulting in improved detection precision. Finally, the improved YOLOv8 model is compared with other models to validate the effectiveness of the proposed improvements. The research results demonstrate that the Tea-YOLOv8s model achieves a mean average precision of 88.27% and an inference time of 37.1 ms, with an increase in the parameters and calculation amount by 15.4 M and 17.5 G, respectively. In conclusion, although the proposed approach increases the model's parameters and calculation amount, it significantly improves various aspects compared to mainstream YOLO detection models and has the potential to be applied to tea buds picked by mechanization equipment.
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•Overview of the current status of type I PDT achieved by inorganic PSs.•Demonstration of strategies employed for transformation of organic PSs from type II to type I ...pathway.•Emphasize the potentiality of supramolecular assembly as a novel non-covalent strategy to promote type I PDT.
Photodynamic therapy (PDT) is a promising approach for treatment of cancer and bacterial infection. Upon excitation by light, photosensitizers (PSs) produce reactive oxygen species (ROS), which could induce cell destruction. ROS could be produced via two kinds of photoreactions, which are type I (electron transfer) mechanism producing superoxide anions, hydrogen peroxides and hydroxyl radicals, and type II (energy transfer) mechanism generating singlet oxygen. Traditional type II PDT suffers from the problem of oxygen-dependent. Fortunately, type I mechanism provides a promising solution that makes PDT practically operated in hypoxic environment. In this review, we attempt to provide a systemic overview of a variety of approaches to generate and improve type I PDT. Inorganic PSs possess the intrinsic feature of generating electron-hole pairs under irradiation, resulting in a charge separated state which is favorable for type I pathway. Organic PSs are generally involved in type II PDT. Strategies of covalent modification and metal coordination are employed for transformation from type II to type I pathway. Provided examples focus on macrocycles and ruthenium(II) complex. We finally emphasize the potentiality of supramolecular assembly as a novel non-covalent strategy to promote type I PDT. It provides a facile method to fabricate nanomaterials with multiple functional building blocks, which could tune type I/II PDT without tedious synthesis. It is also involved in optimizing PSs delivery owing to their unique, nanoscale related properties.
Polymeric carbon nitride modified with selected heteroatom dopants was prepared and used as a model photocatalyst to identify and understand the key mechanisms required for efficient photoproduction ...of H2O2 via selective oxygen reduction reaction (ORR). The photochemical production of H2O2 was achieved at a millimolar level per hour under visible‐light irradiation along with 100 % apparent quantum yield (in 360–450 nm region) and 96 % selectivity in an electrochemical system (0.1 V vs. RHE). Spectroscopic analysis in spatiotemporal resolution and theoretical calculations revealed that the synergistic association of alkali and sulfur dopants in the polymeric matrix promoted the interlayer charge separation and polarization of trapped electrons for preferable oxygen capture and reduction in ORR kinetics. This work highlights the key features that are responsible for controlling the photocatalytic activity and selectivity toward the two‐electron ORR, which should be the basis of further development of solar H2O2 production.
Heptazine‐based C3N4 photocatalysts with heteroatom dopants exhibit potassium‐induced interlayer charge separation and local charge polarization on sulfur sites. This facilitates O2 adsorption and the subsequent two‐electron reduction of dioxygen to achieve highly efficient and selective production of H2O2 up to a millimolar level per hour and 100 % apparent quantum yield at 420 nm.
Stratospheric Aerosol Injection (SAI) aims to offset some climate hazards by injecting aerosols into the stratosphere to reflect solar radiation. The lifetime of injected particles influences SAI's ...radiative efficacy—the ratio of radiative forcing to particle mass flux. We employ a Lagrangian trajectory model with particle sedimentation to simulate how background circulations influence the transport of passive particles (without microphysical growth) in the stratosphere and quantify sensitivities of particle lifetime to injection locations. At 20 km, optimizing injection locations can increase particle lifetime by >40%. Injection strategies can be constrained to maintain an interhemispheric balance of particle lifetime without significantly decreasing total lifetime. Generally, increasing injection altitude increases particle lifetime while also increasing costs and environmental impacts of deployment aircraft. Optimizing injection latitude and longitude can relax this altitude‐lifetime trade‐off by increasing lifetime without needing to increase altitude, which warrants further testing in global climate models with aerosol microphysics.
Plain Language Summary
Stratospheric Aerosol Injection (SAI) aims to reduce climate change by increasing the amount of aerosols in the stratosphere. These additional aerosols can reflect additional sunlight to partially offset the energy imbalance caused by greenhouse gases. The lifetime of injected particles in the stratosphere is one of the important factors that can influence the cooling effects of SAI, as particles that stay longer in the stratosphere can reflect more sunlight over their lifetime. We use observed stratospheric winds to simulate the transport of injected particles and then calculate the particle's lifetime in the stratosphere, aiming to understand how lifetime is related to the location and season at which the particles are injected. For particles injected at 20 km altitude, we can increase particle lifetime by >40% by optimally choosing injection locations. Increasing injection altitude can increase particle lifetime while also increasing the costs and environmental impacts of deployment aircraft. Our results suggest that optimizing injection latitude and longitude to increase lifetime can relax the trade‐off between altitude and lifetime by increasing particle lifetime without needing to increase injection altitude.
Key Points
Injection longitudes influence particle lifetime because of zonal asymmetry of poleward winds, especially in the lower stratosphere
Optimizing injection latitude and longitude can increase stratospheric lifetime of injected particles without increasing injection altitude
Injection strategies can be developed to maintain an interhemispheric balance of particle lifetime without compromising total lifetime
Biopsy is the recommended standard for pathological diagnosis of liver carcinoma. However, this method usually requires sectioning and staining, and well-trained pathologists to interpret tissue ...images. Here, we utilize Raman spectroscopy to study human hepatic tissue samples, developing and validating a workflow for in vitro and intraoperative pathological diagnosis of liver cancer. We distinguish carcinoma tissues from adjacent non-tumour tissues in a rapid, non-disruptive, and label-free manner by using Raman spectroscopy combined with deep learning, which is validated by tissue metabolomics. This technique allows for detailed pathological identification of the cancer tissues, including subtype, differentiation grade, and tumour stage. 2D/3D Raman images of unprocessed human tissue slices with submicrometric resolution are also acquired based on visualization of molecular composition, which could assist in tumour boundary recognition and clinicopathologic diagnosis. Lastly, the potential for a portable handheld Raman system is illustrated during surgery for real-time intraoperative human liver cancer diagnosis.
Understanding the interplay between top–down and bottom–up attention in visual working memory (VWM) is crucial, although the specific challenges arising from this interaction remain ambiguous. In ...this study, we address this complexity by examining how cue informativeness and probe status of the salient items influence this interaction. Through three experiments, we manipulated top–down attention by varying probe frequencies using pre-cues and bottom–up attention by varying the visual salience of memory items. Experiment 1 explored cue informativeness at 100% and 50%, while Experiments 2 and 3 maintained cue informativeness at 80% and 50%. Additionally, Experiment 1 tested a few of the salient items, Experiment 2 excluded them, and Experiment 3 tested half of them in each cue condition. Across all experiments, we consistently observed cueing benefits for cue-directed items, albeit with costs to non-cued items. Furthermore, cue informativeness and the probe status of salient items emerged as critical factors influencing the interaction between top–down and bottom–up attention in VWM. These findings underscore the pivotal roles of cue informativeness and salient item relevance in shaping the dynamics of top–down and bottom–up attention within VWM.
Reinforcement learning (RL) is a promising direction in automated parking systems (APSs), as integrating planning and tracking control using RL can potentially maximize the overall performance. ...However, commonly used model-free RL requires many interactions to achieve acceptable performance, and model-based RL in APS cannot continuously learn. In this paper, a data-efficient RL method is constructed to learn from data by use of a model-based method. The proposed method uses a truncated Monte Carlo tree search to evaluate parking states and select moves. Two artificial neural networks are trained to provide the search probability of each tree branch and the final reward for each state using self-trained data. The data efficiency is enhanced by weighting exploration with parking trajectory returns, an adaptive exploration scheme, and experience augmentation with imaginary rollouts. Without human demonstrations, a novel training pipeline is also used to train the initial action guidance network and the state value network. Compared with path planning and path-following methods, the proposed integrated method can flexibly co-ordinate the longitudinal and lateral motion to park a smaller parking space in one maneuver. Its adaptability to changes in the vehicle model is verified by joint Carsim and MATLAB simulation, demonstrating that the algorithm converges within a few iterations. Finally, experiments using a real vehicle platform are used to further verify the effectiveness of the proposed method. Compared with obtaining rewards using simulation, the proposed method achieves a better final parking attitude and success rate.
A systematic approach was developed to understand, in-depth, the mechanisms involved during the inactivation of bacterial cells using photoelectrocatalytic (PEC) processes with Escherichia coli K-12 ...as the model microorganism. The bacterial cells were found to be inactivated and decomposed primarily due to attack from photogenerated H2O2. Extracellular reactive oxygen species (ROSs), such as H2O2, may penetrate into the bacterial cell and cause dramatically elevated intracellular ROSs levels, which would overwhelm the antioxidative capacity of bacterial protective enzymes such as superoxide dismutase and catalase. The activities of these two enzymes were found to decrease due to the ROSs attacks during PEC inactivation. Bacterial cell wall damage was then observed, including loss of cell membrane integrity and increased permeability, followed by the decomposition of cell envelope (demonstrated by scanning electronic microscope images). One of the bacterial building blocks, protein, was found to be oxidatively damaged due to the ROSs attacks, as well. Leakage of cytoplasm and biomolecules (bacterial building blocks such as proteins and nucleic acids) were evident during prolonged PEC inactivation process. The leaked cytoplasmic substances and cell debris could be further degraded and, ultimately, mineralized with prolonged PEC treatment.
Pancreatic carcinoma (PC) is the one of the most common and malignant cancers worldwide. LncRNA taurine upregulated gene 1 (TUG1) was initially identified as a transcript upregulated by taurine, and ...the abnormal expression of TUG1 has been reported in many cancers. However, the biological role and molecular mechanism of TUG1 in PC still needs further investigation.
Quantitative real-time PCR (qRT-PCR) was performed to measure the expression of TUG1 in PC cell lines and tissues. MTT and colony formation assays were used to measure the effect of TUG1 on cell proliferation. A wound healing assay, transwell assay and western blot assay were employed to determine the effect of TUG1 on cell migration and the epithelial mesenchymal transition (EMT) phenotype. RNA-binding protein immunoprecipitation (RIP) and a biotin-avidin pulldown system were performed to confirm the interaction between miR-328 and TUG1. A gene expression array analysis using clinical samples and RT-qPCR suggested that enhancer of zeste homolog 2 (EZH2) was a target of miR-382 in PC.
In this study, we reported that TUG1 was overexpressed in PC tissues and cell lines, and high expression of TUG1 predicted poor prognosis. Further experiments revealed that overexpressed TUG1 promoted cell proliferation, migration and contributed to EMT formation, whereas silenced TUG1 led to opposing results. Additionally, luciferase reporter assays, an RIP assay and an RNA-pulldown assay demonstrated that TUG1 could competitively sponge miR-382 and thereby regulate EZH2.
Collectively, these findings revealed that TUG1 functions as an oncogenic lncRNA that promotes tumor progression, at least partially, by functioning as an endogenous 'sponge' and competing for miR-382 binding to the miRNA target EZH2.
The extensive use of pesticides has promoted the agricultural production, but a series of subsequent environmental issues have drawn the concern of governments and people worldwide, such as ...groundwater and surface water pollutions. In order to remove these pollutants, photocatalysis has emerged as a powerful method. In this paper, the photocatalytic degradation of an organophosphorus pesticide malathion was investigated using an Au–Pd co-modified TiO2 nanotube film (Au–Pd–TiO2). This film was fabricated by simultaneously photo-depositing Au and Pd precursors on a self-organized TiO2 nanotube film. Its morphology and structures were well characterized by a scanning electron microscope (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The photocatalytic experiments revealed that the malathion elimination rate increased by 172% when the photocatalyst of the naked TiO2 nanotube film was replaced by Au–Pd–TiO2. Additionally, the amount of H2O2 yielded on the Au–Pd–TiO2 film in 60min was 2.89 times that on the naked TiO2. The enhanced photocatalytic performance could be attributed to both the effective separation of photo-generated charge carriers and the higher synthesis rate of H2O2. The possible photocatalytic mechanism was discussed.
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