Verification of the expression trend and interaction prediction of innate immune cells and immune-checkpoint molecules in the process of oral mucosal carcinogenesis.

OBJECTIVES: This study aimed to explore the expression trends of innate immune cells and immune-checkpoint molecules validated by data calculation in the process of oral mucosal carcinogenesis, as well as to explore methods of suppressing oral mucosal carcinogenesis based on immunotherapy by predicting their interactions. Me-thods 1) The cancer genome atlas (TCGA) database comprehensively scores immune cells and immune-checkpoint molecules in the process of oral mucosal carcinogenesis and screens out intrinsic immune cells and immune-checkpoint molecules that interfere with tumor immune escape. 2) Clinical patient blood routine data were collected for the statistical analysis of peripheral blood immune cells during the progression of oral mucosal carcinogenesis. Immune cells in peripheral blood that may affect the progression of oral mucosal carcinogenesis were screened. 3) Immunohistochemical staining was performed on intrinsic immune cells and immune-checkpoint molecules validated based on data calculation in various stages of oral mucosal carcinogenesis. 4) Special staining was used to identify innate immune cells in various stages of oral mucosal carcinogenesis based on data-calculation verification. 5) Survival analysis was conducted on intrinsic immune cells and immune-checkpoint molecules validated based on data calculation during the process of oral mucosal carcinogenesis. The association of intrinsic immune cells and immune-checkpoint molecules with the prognosis of oral squamous cell carcinoma was verified. RESULTS: The expression of monocytes and neutrophils increased during the process of oral mucosal carcinogenesis. The expression of eosinophils showed a single peak trend of up and down. The expression of mast cells decreased. In the process of oral mucosal carcinogenesis, the expression of the immune-checkpoint molecules cytotoxic T-lymphocyte-associated protein 4 (CTLA4) and programmed cell death-ligand (PD-L1) increased. The expression trends of monocytes, neutrophils, and eosinophils were positively correlated with those of CTLA4 and PD-L1 immune-checkpoint molecules. The expression trend of mast cells was negatively correlated with the expression of CTLA4 and PD-L1. Monocytes, neutrophils, and eosinophils may promote tumor immune escape mediated by CTLA4 and/or PD-L1, thereby accelerating the progression of oral mucosal carcinogenesis. Mast cells may inhibit tumor immune escape mediated by CTLA4 and/or PD-L1, delaying the progression of oral mucosal carcinogenesis. CONCLUSIONS: Therefore, interference with specific immune cells in innate immunity can regulate the expression of CTLA4 and/or PD-L1 to a certain extent, inhibit tumor immune escape, and delay the progression of oral mucosal carcinogenesis.

Comparison of outcomes and characteristics of patients admitted to the ICU with COVID-19 and other community-acquired pneumonia based on propensity score matching.

OBJECTIVE: To compare the similarities and differences between patients with Coronavirus Disease 2019 (COVID-19) and those with other community-acquired pneumonia (CAP) admitted to the intensive care unit (ICU), utilizing propensity score matching (PSM), regarding hospitalization expenses, treatment options, and prognostic outcomes, aiming to inform the diagnosis and treatment of COVID-19. METHODS: Patients admitted to the ICU of the Third People's Hospital of Datong City, diagnosed with COVID-19 from December 2022 to February 2023, constituted the observation group, while those with other CAP admitted from January to November 2022 formed the control group. Basic information, clinical data at admission, and time from symptom onset to admission were matched using PSM. RESULTS: A total of 70 patients were included in the COVID-19 group and 119 in the CAP group. The patients were matched by the propensity matching method, and 37 patients were included in each of the last two groups. After matching, COVID-19 had a higher failure rate than CAP, but the difference was not statistically significant (73% vs. 51%, p = 0.055). The utilization rate of antiviral drugs (40% vs. 11%, p = 0.003), γ-globulin (19% vs. 0%, p = 0.011) and prone position ventilation (PPV) (27% vs. 0%, p < 0.001) in patients with COVID-19 were higher than those in the CAP, and the differences were statistically significant. The total hospitalization cost of COVID-19 patients was lower than that of CAP patients, and the difference was statistically significant (27889.5 vs. 50175.9, p = 0.007). The hospital stay for COVID-19 patients was shorter than for CAP patients, but the difference was not statistically significant (10.9 vs. 16.6, p = 0.071). CONCLUSION: Our findings suggest that limited medical resources influenced patient outcomes during the COVID-19 pandemic. Addressing substantial demands for ICU capacity and medications during this period could have potentially reduced the mortality rate among COVID-19 patients.

Synergistic regulation of fusion pore opening and dilation by SNARE and synaptotagmin-1.

Fusion pore opening is a transient intermediate state of synaptic vesicle exocytosis, which is highly dynamic and precisely regulated by the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex and synaptotagmin-1 (Syt1). Yet, the regulatory mechanism is not fully understood. In this work, using single-channel membrane fusion electrophysiology, we determined that SNAREpins are important for driving fusion pore opening and dilation but incapable of regulating the dynamics. When Syt1 was added, the closing frequency of fusion pores significantly increased, while the radius of fusion pores mildly decreased. In response to Ca2+, SNARE/Syt1 greatly increased the radius of fusion pores and reduced their closing frequency. Moreover, the residue F349 in the C2B domain of Syt1, which mediates Syt1 oligomerization, was required for clamping fusion pore opening in the absence of Ca2+, probably by extending the distance between the two membranes. Finally, in Ca2+-triggered fusion, the primary interface between SNARE and Syt1 plays a critical role in stabilizing and dilating the fusion pore, while the polybasic region of Syt1 C2B domain has a mild effect on increasing the radius of the fusion pore. In summary, our results suggest that Syt1, SNARE, and the anionic membrane synergically orchestrate the dynamics of fusion pore opening in synaptic vesicle exocytosis.

Comprehensive DNA barcode reference library and optimization of genetic divergence threshold facilitate the exploration of species diversity of green lacewings (Neuroptera: Chrysopidae).

Chrysopidae are a family of Neuroptera of significant importance in biocontrol against agricultural pests because of their predatory larvae. Currently, the taxonomy of Chrysopidae lacks a comprehensive revision, which impedes the exploration of species diversity as well as the selection and the conservation of green lacewings as biocontrol agents. We have established a DNA barcode reference library of the Chinese green lacewings based on an approximately complete sampling (95.63%) in 25 of the 34 provincial regions in China, comprising 1 119 barcodes of 25 genera and 197 species (representing 85% genera and 43.62% species from China). Combining other 1 049 high quality green lacewing DNA barcodes, we first inferred the optimal threshold of interspecific genetic divergence (1.87%) for successful species identification in multiple simulated scenarios based on present data. We further inferred the threshold of genetic divergence (7.77%) among genera with biocontrol significance. The inference and performance of the threshold appears to be mainly associated with the completeness of sampling, the proportion of closely related species, and the analytical approaches. Six new combinations, Apertochrysa platypa (Yang & Yang, 1991) comb. nov., Apertochrysa shennongana (Yang & Wang, 1990) comb. nov., Apertochrysa pictifacialis (Yang, 1988) comb. nov., Apertochrysa helana (Yang, 1993) comb. nov., Plesiochrysa rosulata (Yang & Yang, 2002) comb. nov., and Signochrysa hainana (Yang & Yang, 1991), are proposed according to integrative species delimitation. Our library and optimal threshold will effectively facilitate the exploration of species diversity of green lacewings. Our study also provides a methodological reference in molecular delimitation of other insects.

Development of a Deep Learning Model for Diagnosing Lumbar Spinal Stenosis Based on CT Images.

STUDY DESIGN: Retrospective study. OBJECTIVES: This study aimed to develop an initial deep learning model based on CT scans for diagnosing lumbar spinal stenosis. SUMMARY OF BACKGROUND DATA: MRI is commonly used for diagnosing lumbar spinal stenosis due to its high soft tissue resolution, but CT is more portable, cost-effective, and has wider regional coverage. Using deep learning models to improve the accuracy of CT diagnosis can effectively reduce missed diagnoses and misdiagnoses in clinical practice. METHODS: Axial lumbar spine CT scans obtained between March 2022 and September 2023 were included. The dataset was divided into a training set (62.3%), a validation set (22.9%), and a control set (14.8%). All data were labeled by two spine surgeons using the widely accepted grading system for lumbar spinal stenosis. The training and validation sets were used to annotate the ROIs by the two spine surgeons. First, an ROI detection model and a CNN classifier were trained using the training set. After training, the model was preliminarily evaluated using a validation set. Finally, the performance of the deep learning model was evaluated on the control set, and a comparison was made between the model and classification performance of specialists with varying levels of experience. RESULTS: The central stenosis grading accuracies of DL Model Version 1 and DL Model Version 2 were 88% and 83%, respectively. The lateral recess grading accuracies of DL Model Version 1 and DL Model Version 2 were 75% and 71%, respectively. CONCLUSIONS: Our preliminarily developed deep learning system for assessing the degree of lumbar spinal stenosis in CT, including the central canal and lateral recess, has shown similar accuracy to experienced specialist physicians. This holds great value for further development and clinical application.

Complications and radiographic changes after implantation of interspinous process devices: average eight-year follow-up.

PURPOSE: This study aims to evaluate complications, clinical outcomes, and radiographic results following Coflex implantation. METHODS: We retrospectively studied 66 patients who had decompressive surgery combined with Coflex implantation to treat lumbar spinal stenosis. All imaging data were collected and examined for imaging changes. Clinical outcomes, included Oswestry Disability Index (ODI), back and leg visual analog scale (VAS) scores, were evaluated before surgery, six months after surgery and at the last follow-up. The number of complications occurring after five years of follow-up was counted. All reoperation cases were meticulously recorded. RESULTS: 66 patients were followed up for 5-14 years. The VAS and ODI scores were significantly improved compared with baseline. Heterotopic Ossification (HO) was detectable in 59 (89.4%). 26 (39.4%) patients had osteolysis at the contact site of Coflex with the spinous process. Coflex loosening was detected in 39 (60%) patients. Spinous process anastomosis was found in 34 (51.5%) patients. There was a statistically significant difference in the VAS score of back pain between patients with and without spinous process anastomosis. Nine cases of lumbar spinal restenosis were observed, and prosthesis fracture was observed in one case. CONCLUSION: Our study identified various imaging changes after Coflex implantation, and majority of them did not affect clinical outcomes. The majority of patients had HO, but osteolysis and Coflex loosening were relatively rare. The VAS score for back pain of these patients was higher if they have spinous process anastomosis. After five-year follow-up, we found lumbar spinal restenosis and prosthesis fracture cases.

A Suitable Membrane Distance Regulated by the RBD_ACE2 Interaction is Critical for SARS-CoV-2 Spike-Mediated Viral Invasion.

The receptor-binding domain (RBD) of spike recognizing the receptor angiotensin-converting enzyme 2 (ACE2) initiates membrane fusion between severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and cell membrane. Although the structure of the RBD_ACE2 complex has been well studied, its functional mechanism in membrane fusion is still not fully understood. Here, using an in vitro cell-vesicle content-mixing assay, it is found that the cleavage at the S2' site by thrombin (Thr) protease strongly accelerates membrane fusion, compared to that of cleavage at the S1/S2 site by PreScission (3C) protease. Moreover, mutations at the RBD_ACE2 interface resulted in a positive correlation between binding affinity and fusion probability. In both the cell-vesicle and cell-cell fusion assays, by crosslinking two membranes via the neutravidin (NTV)_biotin interaction or complementary DNA strands, it is found that spike drives membrane fusion in the absence of ACE2, and a suitable distance between two membranes is critical for spike-mediated membrane fusion. Finally, unsuitable membrane crosslinkers significantly inhibited the fusion probability in the presence of ACE2. Taken together, the results suggest that the RBD_ACE2 complex may act as a crosslinker to bridge the viral and cell membranes at a suitable distance, which is critical, but also substitutable for spike-mediated SARS-CoV-2 entry.

A tomato disease identification method based on leaf image automatic labeling algorithm and improved YOLOv5 model.

BACKGROUND: Tomato is one of the most important vegetables in the world. Timely and accurate identification of tomato disease is a critical way to ensure the quality and yield of tomato production. The convolutional neural network is a crucial means of disease identification. However, this method requires manual annotation of a large amount of image data, which wastes the human cost of scientific research. RESULTS: To simplify the process of disease image labeling and improve the accuracy of tomato disease recognition and the balance of various disease recognition effects, a BC-YOLOv5 tomato disease recognition method is proposed to identify healthy growth and nine types of diseased tomato leaves. In the present study, the YOLOv5 model is improved by designing an automatic tomato leaf image labeling algorithm, using the weighted bi-directional feature pyramid network to change the Neck structure, adding the convolution block attention module, and changing the input channel of the detection layer. Experiments show that the BC-YOLOv5 method has an excellent image annotation effect on tomato leaves, with a pass rate exceeding 95%. Furthermore, compared with existing models, the performance indices of BC-YOLOv5 to identify tomato diseases are the best. CONCLUSION: BC-YOLOv5 realizes the automatic labeling of tomato leaf images before the start of training. This method not only identifies nine common tomato diseases, but also improve the accuracy of disease identification and have a more balanced identification effect on various diseases. It provides a reliable method for the identification of tomato disease. © 2023 Society of Chemical Industry.

Research on the evaluation method of steam power system operation status based on the theory of deterioration degree and health value.

The evaluation of the steam power system is very important for the operator to understand the operating status of the system, but the lack of consideration of the fuzziness of the complex system and the impact of the indicator parameters on the whole system makes the evaluation difficult. In this paper, an indicator system for evaluating the operation status of the experimental supercharged boiler is established. After discussing several methods of parameter standardization and weight correction, a comprehensive evaluation method based on the deterioration degree and health value is proposed while considering the deviation of the indicator and the fuzziness of the system. The comprehensive evaluation method, the linear weighting method and the fuzzy comprehensive evaluation method are respectively used to evaluate the experimental supercharged boiler. The comparison of the three methods shows that the comprehensive evaluation method is more sensitive to minor anomalies and faults and can draw quantitative health assessment conclusions.

Cryo-EM-guided engineering of T-box-tRNA modules with enhanced selectivity and sensitivity in translational regulation.

Riboswitches are non-coding RNA elements that play vital roles in regulating gene expression. Their specific ligand-dependent structural reorganization facilitates their use as templates for design of engineered RNA switches for therapeutics, nanotechnology and synthetic biology. T-box riboswitches bind tRNAs to sense aminoacylation and control gene expression via transcription attenuation or translation inhibition. Here we determine the cryo-EM structure of the wild-type Mycobacterium smegmatis ileS T-box in complex with its cognate tRNA Ile . This structure shows a very flexible antisequestrator region that tolerates both 3'-OH and 2',3'-cyclic phosphate modification at the 3' end of tRNA Ile . Elongation of one helical turn (11-base pair) in both the tRNA acceptor arm and T-box Stem III maintains T-box-tRNA complex formation and increases the selectivity for tRNA 3' end modification. Moreover, elongation of Stem III results in ∼6-fold tighter binding to tRNA, which leads to increased sensitivity of downstream translational regulation indicated by precedent translation. Our results demonstrate that cryo-EM can guide RNA engineering to design improved riboswitch modules for translational regulation, and potentially a variety of additional functions.

[Effect of up-regulation of Decorin on expression of EGFR, C-Myc and p21 in nude mice with oral squamous cell carcinoma].

PURPOSE: To explore the effect of overexpression of DCN（decorin） gene on the expression of epidermal growth factor receptor (EGFR), cellular-myelocytomatosis viral oncogene (C-Myc) and cyclin dependent kinase inhibitor (p21)in tumor-bearing nude mice with oral squamous cell carcinoma（OSCC）. METHODS: The expression of DCN gene in human oral squamous cell carcinoma(HSC-3) was up-regulated by liposome transfection. Nude mice were used as the carrier of OSCC. H-E staining was used to determine the pathological grade of tumor-bearing tissues in each group. Immunohistochemistry was used to detect the expression of EGFR, C-Myc and p21 protein in tumor-bearing tissues of each group after DCN overexpression. RT-qPCR and Western blot were used to quantitatively detect the expression of EGFR, C-Myc and p21 in tumor-bearing tissues of each group after DCN overexpression, and to determine the effects of DCN overexpression on the expression of EGFR, C-Myc and p21 in tumor-bearing tissues of OSCC nude mice. SPSS 20.0 software package was used for statistical analysis. RESULTS: H-E staining showed that the animal model of OSCC was successfully constructed. The tumor-bearing tissues of nude mice in the plasmid group were significantly lighter than those in the empty vector group and non-transfected group(P＜0.05). IHC results showed that DCN, EGFR, C-Myc and p21 proteins were expressed in the tumor-bearing tissues of nude mice in each group, the expression of DCN,EGFR and C-Myc proteins in the plasmid group was significantly different from the other groups(P＜0.05).There was no significant differece in p21 protein expression in each group(P＞0.05). RT-qPCR and Western blot results showed that DCN, EGFR, C-Myc and p21 were expressed in diffrent degrees in tumor-bearing tissues of nude mice（P＜0.05）. CONCLUSIONS: DCN can inhibit the growth of tumor in OSCC nude mice. In tumor-bearing tissues of nude mice with OSCC, overexpression of DCN can down-regulate the expression of EGFR and C-Myc, and up-regulate the expression of p21.DCN may play an inhibitory role in the occurrence and development of OSCC.

The Gray Mold Spore Detection of Cucumber Based on Microscopic Image and Deep Learning.

Rapid and accurate detection of pathogen spores is an important step to achieve early diagnosis of diseases in precision agriculture. Traditional detection methods are time-consuming, laborious, and subjective, and image processing methods mainly rely on manually designed features that are difficult to cope with pathogen spore detection in complex scenes. Therefore, an MG-YOLO detection algorithm (Multi-head self-attention and Ghost-optimized YOLO) is proposed to detect gray mold spores rapidly. Firstly, Multi-head self-attention is introduced in the backbone to capture the global information of the pathogen spores. Secondly, we combine weighted Bidirectional Feature Pyramid Network (BiFPN) to fuse multiscale features of different layers. Then, a lightweight network is used to construct GhostCSP to optimize the neck part. Cucumber gray mold spores are used as the study object. The experimental results show that the improved MG-YOLO model achieves an accuracy of 0.983 for detecting gray mold spores and takes 0.009 s per image, which is significantly better than the state-of-the-art model. The visualization of the detection results shows that MG-YOLO effectively solves the detection of spores in blurred, small targets, multimorphology, and high-density scenes. Meanwhile, compared with the YOLOv5 model, the detection accuracy of the improved model is improved by 6.8%. It can meet the demand for high-precision detection of spores and provides a novel method to enhance the objectivity of pathogen spore detection.

The association between vertical laminar fracture and recurrent kyphosis after implant removal of Thoracolumbar burst fracture: a retrospective study.

BACKGROUND: Surgeons often encounter recurrent kyphosis of Cobb angle following thoracolumbar burst fracture surgery. Some factors affecting postoperative correction loss have been studied in previous studies, but few have examined the relationship between laminar fractures and postoperative loss of correction. METHODS: The clinical data of 86 patients with thoracolumbar burst fracture who met the inclusion criteria and were admitted to our Department of Spine Surgery between 2013 and 2020 was retrospectively analyzed. To examine the association between laminar fracturs and postoperative correction loss, demographic and radiographic characteristics of the two groups were analyzed. RESULTS: The presence or absence of laminar fractures was statistically different between the two groups (P < 0.05). Binary logistic regression analysis showed that laminar fractures and preoperative Cobb were statistically significant in the two groups. There were statistically significant differences in the degree of injury of laminar fractures in the coronal plane between the two groups (P < 0.05). CONCLUSION: This study investigated that the presence or absence of laminar fractures and preoperative Cobb contribute to loss of correction after thoracolumbar burst fracture surgery. There was a statistically significant difference between full-length and partial-length laminar fractures on the loss of postoperative correction of thoracolumbar burst fractures with laminar fractures.

Fecal calprotectin as an indicator in risk stratification of pouchitis following ileal pouch-anal anastomosis for ulcerative colitis.

BACKGROUND: Pouchitis is the most common complication following restorative proctocolectomy and ileal pouch-anal anastomosis (IPAA) for ulcerative colitis (UC). Fecal calprotectin (FC) is a noninvasive indicator of the intestinal inflammatory status. This study was conducted to evaluate the clinical value of the FC concentration for the diagnosis and risk assessment of pouchitis. PATIENTS AND METHODS: This retrospective study involved patients who underwent IPAA for UC at Tianjin Medical University General Hospital from January 2015 to January 2019. The patients were categorized into pouchitis and non-pouchitis groups based on their Pouchitis Disease Activity Index (PDAI) score. Laboratory indicators, including the FC concentration, were collected from both groups. RESULTS: Sixty-six patients with UC after IPAA were included in the study and divided into the non-pouchitis group (n = 40) and pouchitis group (n = 26). The correlation coefficient between the FC concentration and the PDAI score was 0.651 (p < 0.001). Receiver operating characteristic analysis showed that the FC cut-off value for predicting pouchitis was 579.60 µg/g (area under the curve, 0.938). The patients were then divided into three subgroups according to their PDAI score (0-2, 3-6, and ≥7), and significant differences in the FC concentration were found among the three subgroups. The best FC cut-off value for predicting a high risk of pouchitis (PDAI score of 3-6) was 143.25 µg/g (area under the curve, 0.876). CONCLUSIONS: FC is a useful biomarker in patients with pouchitis. Patients are advised to regularly undergo FC measurement to monitor for pouchitis. An FC concentration in the range of 143.25-579.60 µg/g is predictive of a high risk for pouchitis, and further examination and preventive treatment are necessary in such patients.KEY MESSAGESFecal calprotectin can be used to quantify pouch inflammation.Fecal calprotectin can be used to predict a high risk of pouchitis.

Chemical constituents of Aspergillus udagawae isolated from the soil of the Xingren coal areas and their antibacterial activities.

A new helvolic acid derivative (1), together with nine known compounds (2-10) were isolated from the metabolites of Aspergillus udagawae MST1-10 with the bioassay-guided fractionation method. Their structures were identified on the basis of spectroscopic analysis. The absolute configuration of compound 1 was elucidated through NOESY and ECD spectra. Compound 2 displayed significant antibacterial activities against Stenotrophomonas maltophilia with MIC value of 2 µg/mL (Trimethoprim, MIC = 64 µg/mL), and with biofilm inhibition rates of 96.41%, 87.77%, and 41.70% at 4MIC, 2MIC, and MIC, respectively.

Biodegradable Mulching Films Based on Polycaprolactone and Its Porous Structure Construction.

Polycaprolactone (PCL) is one of the promising linear aliphatic polyesters which can be used as mulching film. Although it has suitable glass transition temperature and good biodegradability, further practical applications are restricted by the limited temperature-increasing and moisturizing properties. The rational design of the PCL structure is a good strategy to enhance the related properties. In this study, thermally-induced phase separation (TIPS) was introduced to fabricate a PCL nanoporous thin film. The introduction of a nanoporous structure on the PCL surface (np-PCL) exhibited enhanced temperature-increasing and moisturizing properties when used as mulch film. In detail, the average soil temperature of np-PCL was increased to 17.81 °C, when compared with common PCL of 17.42 °C and PBAT of 17.50 °C, and approaches to PE of 18.02 °C. In terms of water vapor transmission rate, the value for np-PCL is 637 gm-2day-1, which was much less than the common PCL of 786 and PBAT of 890 gm-2day-1. As a result, the weed biomass under the np-PCL was suppressed to be 0.35 kg m-2, almost half of the common PCL and PBAT. In addition, the np-PCL shows good thermal stability with an onset decomposition temperature of 295 °C. The degradation mechanism and rate of the np-PCL in different pH environments were also studied to explore the influence of nanoporous structure. This work highlights the importance of the nanoporous structure in PCL to enhance the temperature-increasing and moisturizing properties of PCL-based biodegradable mulching film.

New Meroterpenoid and Isocoumarins from the Fungus Talaromyces amestolkiae MST1-15 Collected from Coal Area.

Three new compounds including a meroterpenoid (1) and two isocoumarins (8 and 9), together with thirteen known compounds (2-7, 10-16) were isolated from the metabolites of Talaromyces amestolkiae MST1-15. Their structures were identified by a combination of spectroscopic analysis. The absolute configuration of compound 1 was elucidated on the basis of experimental and electronic circular dichroism calculation, and compounds 8 and 9 were determined by Mo2(OAc)4-induced circular dichroism experiments. Compounds 7-16 showed weak antibacterial activities against Stenotrophomonas maltophilia with MIC values ranging from 128 to 512 µg/mL (MICs of ceftriaxone sodium and levofloxacin were 128 and 0.25 µg/mL, respectively).

Attention-optimized DeepLab V3 + for automatic estimation of cucumber disease severity.

BACKGROUND: Automatic and accurate estimation of disease severity is critical for disease management and yield loss prediction. Conventional disease severity estimation is performed using images with simple backgrounds, which is limited in practical applications. Thus, there is an urgent need to develop a method for estimating the disease severity of plants based on leaf images captured in field conditions, which is very challenging since the intensity of sunlight is constantly changing, and the image background is complicated. RESULTS: This study developed a simple and accurate image-based disease severity estimation method using an optimized neural network. A hybrid attention and transfer learning optimized semantic segmentation model was proposed to obtain the disease segmentation map. The severity was calculated by the ratio of lesion pixels to leaf pixels. The proposed method was validated using cucumber downy mildew, and powdery mildew leaves collected under natural conditions. The results showed that hybrid attention with the interaction of spatial attention and channel attention can extract fine lesion and leaf features, and transfer learning can further improve the segmentation accuracy of the model. The proposed method can accurately segment healthy leaves and lesions (MIoU = 81.23%, FWIoU = 91.89%). In addition, the severity of cucumber leaf disease was accurately estimated (R2 = 0.9578, RMSE = 1.1385). Moreover, the proposed model was compared with six different backbones and four semantic segmentation models. The results show that the proposed model outperforms the compared models under complex conditions, and can refine lesion segmentation and accurately estimate the disease severity. CONCLUSIONS: The proposed method was an efficient tool for disease severity estimation in field conditions. This study can facilitate the implementation of artificial intelligence for rapid disease severity estimation and control in agriculture.

[Effects of Biochar Application on Yellow Soil Nutrients and Enzyme Activities].

Due to its special physical and chemical properties, biochar is widely used as a multi-beneficial amendment to improve soil quality. Soil nutrient content and enzyme activities are important chemical and biological factors indicating soil quality. Despite increased interest and studies, a knowledge gap remains regarding the ability of biochar to assess soil nutrient content and enzyme activities due to differences in biochar application amount and soil texture. In the present study, the effects of different amounts of biochar application (CK:0 t·hm-2, B5:5 t·hm-2, B10:10 t·hm-2, B20:20 t·hm-2, and B50:50 t·hm-2) on soil nutrient content and enzyme activities were studied based on a field experiment on typical yellow soil in Guizhou province, southwest China. Structural equation models (SEM) were used to quantitatively evaluate the direct or indirect effects of biochar application on soil nutrient content and enzyme activities. The results showed that soil pH, electrical conductivity (EC), soil organic carbon (SOC), alkaline hydrolysis nitrogen (AHN), available phosphorus (AP), and available potassium (AK) increased with the applied amount of biochar. With the increase in biochar application amount, the activities of soil catalase and urease showed first an increasing and then a decreasing trend, and the activities of soil sucrase and phosphatase showed an almost constant increasing trend (P<0.05). The highest activities of soil catalase, urease, and phosphatase were recorded under treatment B10. A relatively high activity of soil sucrose was also observed under treatment B10. With the same amount of biochar application, soil pH and the content of soil AHN, AP, and AK in treatments after four months of biochar application were greater than those after 12 months. After 12 months of biochar application treatment, the contents of SOC and EC were greater than those at four months. Compared to those in treatments after four months of biochar application, activities of soil urease and phosphatase increased, activities of soil catalase decreased, and activities of soil sucrose did not obviously change after 12 months of biochar application. The results of SEM showed that biochar application directly decreased activities of soil catalase and indirectly promoted activities of soil sucrase and phosphatase by increasing soil pH, EC, AHN, AK, and AP. In conclusion, the amount and duration of biochar application significantly increased soil nutrient content, directly and indirectly affecting soil enzyme activities. Based on the results of the presents study, biochar application at 10 t·hm-2 was recommended for acidic yellow soil.