Fine-grained recognition of bitter gourd maturity based on Improved YOLOv5-seg model.

Bitter gourd, being perishable, requires timely harvesting. Delayed harvesting can result in a substantial reduction in fruit quality. while premature harvesting leads to underdeveloped fruit and decreased yields, the continuous flowering pattern in bitter gourd underscores the significance of accurately assessing fruit growth and ensuring timely harvesting for subsequent fruit setting and development. The current reliance on the experience of production personnel represents a substantial inefficiency. We present an improved real-time instance segmentation model based on YOLOv5-seg. The utilization of dynamic snake convolution enables the extraction of morphological features from the curved and elongated structure of bitter gourd. Diverse branch blocks enhance feature space diversity without inflating model size and inference time, contributing to improved recognition of expansion stages during bitter gourd growth. Additionally, the introduction of Focal-EIOU loss accurately locates the boundary box and mask, addressing sample imbalances in the L2 stage. Experimental results showcase remarkable accuracy rates of 99.3%, 93.8%, and 98.3% for L1, L2, and L3 stages using mAP@0.5. In comparison, our model outperforms other case segmentation models, excelling in both detection accuracy and inference speed. The improved YOLOv5-seg model demonstrates strong performance in fine-grained recognition of bitter gourd during the expansion stage. It efficiently segments bitter gourd in real-time under varying lighting and occlusion conditions, providing crucial maturity information. This model offers reliable insights for agricultural workers, facilitating precise harvesting decisions.

Ratiometric fluorescence and absorbance dual-model immunoassay based on 2,3-diaminophenazine and carbon dots for detecting Aflatoxin B1.

In this work, a dual-model immunoassay for detecting Aflatoxin B1 (AFB1) was developed based on 2,3-diaminophenazine (DAP) and carbon dots (CDs). Under the catalysis of horseradish peroxidase (HRP), the o-phthalylenediamine (OPD) was oxidized to DAP which had a yellow color and intense fluorescence. The color changes form colorless to yellow was used to design absorbance model immunoassay. Meanwhile, the absorption spectrum of DAP overlapped with the emission spectrum of CDs which caused the fluorescence of CDs to be quenched. The fluorescence changes of DAP and CDs were used to develop ratiometric fluorescence immunoassay. The dual-model immunoassay showed excellent sensitivity with the limits of detection (LODs) of 0.013 ng/mL for fluorescence mode and 0.062 ng/mL for absorbance mode. Meanwhile, both models exhibited great selectivity for AFB1. Additionally, the recovery rates suggested the proposed dual-model immunoassay had great potential in actual samples detection.

Ratiometric fluorescence immunoassay based on silver nanoclusters and calcein-Ce3+ for detecting ochratoxin A.

Ochratoxin A (OTA), a dangerous mycotoxin, is found in many crops. It is essential to create sensitive OTA detection techniques to ensure food safety. Based on the principle of p-nitrophenol (PNP) quenched the fluorescence of bovine serum albumin silver nanocluster (BSA-AgNCs) through an internal filtering effect, and phosphate activated fluorescence of calcein-Ce3+ system, a ratiometric fluorescence immunoassay for OTA detection was developed. In this strategy, the value of F518/F640 was used as a signal for response of OTA concentration. The detection range of this strategy was 0.625-25 ng/mL, the limit of detection (LOD) was 0.04 ng/mL. This new immunoassay offered a brand-new platform for detecting OTA.

DSIL-DDI: A Domain-Invariant Substructure Interaction Learning for Generalizable Drug-Drug Interaction Prediction.

Drug-drug interactions (DDIs) trigger unexpected pharmacological effects in vivo, often with unknown causal mechanisms. Deep learning methods have been developed to better understand DDI. However, learning domain-invariant representations for DDI remains a challenge. Generalizable DDI predictions are closer to reality than source domain predictions. For existing methods, it is difficult to achieve out-of-distribution (OOD) predictions. In this article, focusing on substructure interaction, we propose DSIL-DDI, a pluggable substructure interaction module that can learn domain-invariant representations of DDIs from source domain. We evaluate DSIL-DDI on three scenarios: the transductive setting (all drugs in test set appear in training set), the inductive setting (test set contains new drugs that were not present in training set), and OOD generalization setting (training set and test set belong to two different datasets). The results demonstrate that DSIL-DDI improve the generalization and interpretability of DDI prediction modeling and provides valuable insights for OOD DDI predictions. DSIL-DDI can help doctors ensuring the safety of drug administration and reducing the harm caused by drug abuse.

Construction Sheets Made of High-Performance Flame-Retardant Nonwoven Fabrics and Combustion-Resistant Polyurethane Foam: Preparation Process and Property Evaluations.

In this study, nonwoven fabrics, rigid polyurethane foam (RPUF), Basalt woven fabrics, and an aluminum foil film mold are used to produce multi-functional composite sheets with flame-retardant, sound-absorbing, and electromagnetic-shielding functions. The nonwoven layer is composed of Nomex fibers, flame-retardant PET fibers, and low-melting-point (LMPET) fibers via the needle rolling process. The optimal Nomex fiber/flame-retardant PET fiber/LMPET fiber (N/F/L) nonwoven fabrics are then combined with rigid polyurethane (PU) foam, Basalt woven fabric, and an aluminum foil film mold, thereby producing nonwoven/rigid polyurethane foam/Basalt woven fabric composite sheets that are wrapped in the aluminized foil film. The test results indicate that formed with a foaming density of 60 kg/m3 and 10 wt% of a flame retardant, the composite sheets exhibit electromagnetic interference shielding efficacy (EMI SE) that exceeds 40 dB and limiting oxygen index (LOI) that is greater than 26. The efficient and highly reproducible experimental design proposed in this study can produce multifunctional composite sheets that feature excellent combustion resistance, sound absorption, and EMI SE and are suitable for use in the transportation, industrial factories, and building wall fields.

Kinetic Controlled Chirality Transfer and Induction in 2D Hydrogen-Bonding Assemblies of Glycylglycine on Au(111).

Chirality transfer is of vital importance that dominates the structure and functionality of biological systems and living matters. External physical stimulations, e.g. polarized light and mechanical forces, can trigger the chirality symmetry breaking, leading to the appearance of the enantiomeric entities created from a chiral self-assembly of achiral molecule. Here, several 2D assemblies with different chirality, synthesized on Au(111) surface by using achiral building blocks - glycylglycine (digly), the simplest polypeptide are reported. By delicately tuning the kinetic factors, i.e., one-step slow/rapid deposition, or stepwise slow deposition with mild annealing, achiral square hydrogen-bond organic frameworks (HOF), homochiral rhombic HOF and racemic rectangular assembly are achieved, respectively. Chirality induction and related symmetry broken in assemblies are introduced by the handedness (H-bond configurations in principle) of the assembled motifs and then amplified to the entire assemblies via the interaction between motifs. The results show that the chirality transfer and induction of biological assemblies can be tuned by altering the kinetic factors instead of applying external forces, which may offer an in-depth understanding and practical approach to peptide chiral assembly on the surfaces and can further facilitate the design of desired complex biomolecular superstructures.

Characterization of highly polymorphic microsatellite markers for the chinese monal (Lophophorus lhuysii, Galliformes) using Illumina MiSeq sequencing.

BACKGROUND: The Chinese monal (Lophophorus lhuysii, Galliformes) is a vulnerable and endemic bird from southwestern China. To better protect this species and increase its population size, genetic markers are urgently needed for investigation and conservation of both wild and captive populations. METHODS AND RESULTS: By using next-generation sequencing, we developed and characterized markers for seven microsatellite loci of the Chinese monal. PCR examination and statistical analysis indicated that these microsatellites exhibited moderate to high levels of polymorphism, with the expected heterozygosity and polymorphic information content ranging from 0.578 to 0.858 and from 0.540 to 0.841, respectively. Cross-species genome comparison further suggests that these microsatellites are a feature of certain galliform species rather than being specific to the Chinese monal. CONCLUSION: A combination of the seven highly polymorphic loci may provide a fundamental genetic toolkit to assess genetic backgrounds and will contribute to design conservation plan, breeding management and other possible studies of the Chinese monal and other evolutionarily related species in the future.

Development of DNA Biosensors Based on DNAzymes and Nucleases.

DNA biosensors play important roles in environmental, medical, industrial and agricultural analysis. Many DNA biosensors have been designed based on the enzyme catalytic reaction. Because of the importance of enzymes in biosensors, we present a review on this topic. In this review, the enzymes were divided into DNAzymes and nucleases according to their chemical nature. Firstly, we introduced the DNAzymes with different function inducing cleavage, metalation, peroxidase, ligation and allosterism. In this section, the G-quadruplex DNAzyme, as a hot topic in recent years, was described in detail. Then, the nucleases-assisted signal amplification method was also reviewed in three categories including exonucleases, endonucleases and other nucleases according to the digestion sites in DNA substrates. In exonucleases section, the Exo I and Exo III were selected as examples. Then, the DNase I, BamH I, nicking endonuclease, S1 nuclease, the duplex specific nuclease (DSN) and RNases were chosen to illustrate the application of endonucleases. In other nucleases section, DNA polymerases and DNA ligases were detailed. Last, the challenges and future perspectives in the field were discussed.

MnO2 nanosheets-triggered oxVB1 fluorescence immunoassay for detection zearalenone.

In this study, an alkaline phosphatase (ALP)-mediated fluorescence immunoassay for detecting zearalenone (ZEN) was established based on the oxVB1 fluorescence signal modulated by MnO2 nanosheets (MnO2 NS). As the ALP-antibody content increased, more 2-phosphoascorbic acid (AAP) was hydrolyzed to ascorbic acid (AA) which destroyed the MnO2 NS rapidly. In the lack of MnO2 NS, VB1 cannot be oxidized to oxVB1 for emitting fluorescence. On the contrary, the fluorescence of oxVB1 recovered slowly with the decrease of the ALP-antibody concentration. In the optimization condition, the detection limit of this method was 15.5 pg mL-1. Moreover, the recovery of ZEN in real samples ranged from 94.24 % to 108.26 %, which indicated the remarkable accuracy and reliability of this approach. Meanwhile, the proposal of this fluorescence immunoassay provided a new possibility for detecting other targets by replacing antibodies and antigens.

Fluorescence and colorimetric dual-mode immunoassay based on G-quadruplex/N-methylmesoporphyrin IX and p-nitrophenol for detection of zearalenone.

In this work, a fluorescence and colorimetric dual-mode immunoassay for detecting zearalenone (ZEN) was established. This platform relied on the dephosphorylation of p-nitrophenyl phosphate (PNPP) by alkaline phosphatase (ALP) to produce yellow p-nitrophenol (PNP). And the internal filtration effect between G-quadruplex/N-methylmesoporphyrin IX (G4/NMM) and PNP led to fluorescence quenching of G4/NMM. Therefore, the color change of PNP and the fluorescence change of G4/NMM can be used as double signals to report the results of ALP mediated immunoassay. In this dual-mode immunoassay, the detection limit of fluorescence mode was 0.0072 ng/mL with a linear range 7.5-17.5 ng/mL. And the detection limit of colorimetric mode was 0.036 ng/mL with a linear range 7.5-20 ng/mL. In addition, the dual-mode immunoassay showed good selectivity for ZEN and satisfactory recovery in corn samples (fluorescence mode: 94.40-106.80%, colorimetric mode: 96.51-108.27%).

Cerium ions triggered dual-readout immunoassay based on aggregation induced emission effect and 3,3',5,5'-tetramethylbenzidine for fluorescent and colorimetric detection of ochratoxin A.

Ochratoxin A (OTA) is one of the most prevalent and toxic mycotoxins. Ultrasensitive and convenient detection of OTA is urgent demanded for public health. In this work, a dual-readout immunoassay was established for the detection of OTA based on Ce4+ oxidizing 3,3',5,5'-tetramethylbenzidine (TMB) and Ce3+ inducing aggregation induced emission (AIE) of Au nanoclusters (AuNCs). Under alkaline phosphatase (ALP), the ascorbic acid 2-phosphate (AA2P) can form ascorbic acid (AA) by dephosphorylation. The AA can reduce Ce4+ to generate Ce3+, which induced the AIE of AuNCs to enhance the fluorescence intensity of AuNCs. Meanwhile, unreacted Ce4+ oxidized TMB to form blue oxTMB. Thus, a dual-readout immunoassay was developed based on AIE of AuNCs and TMB as substrate. The limits of detection (LODs) were as low as 0.62 ng/mL for fluorescent assay and 0.81 ng/mL for colorimetric assay. The recoveries of OTA from corn were 94.4%-107.7% for the fluorescent mode and 93.7%-106.9% for the colorimetric mode. The results verified that the cerium ions triggered dual-readout immunoassay was reliable to sensitive detect OTA in corn samples.

Automatic Segmentation of Lumbar Spine MRI Images Based on Improved Attention U-Net.

Lumbar spine segmentation is important to help doctors diagnose lumbar disc herniation (LDH) and patients' rehabilitation treatment. In order to accurately segment the lumbar spine, a lumbar spine image segmentation algorithm based on improved Attention U-Net is proposed. The algorithm is based on Attention U-Net, the attention module based on multilevel feature map fusion is adopted, two residual modules are introduced instead of the original convolution blocks. a hybrid loss function is used for prediction during the training process, and finally, the image superposition process is realized. In this experiment, we expanded 420 lumbar MRI images of 180 patients to 1000 images and trained them by different algorithms, respectively, and accuracy, recall, and Dice similarity coefficient metrics were used to analyze these algorithms. The results show that compared with SVM, FCN, R-CNN, U-Net, and Attention U-Net models, the improved model achieved better results in all three evaluations, with 95.50%, 94.53%, and 95.01%, respectively, which proves the better performance of the proposed method for segmentation in lumbar disc and caudal vertebrae.

MRI-Based Medical Image Recognition: Identification and Diagnosis of LDH.

To realize the automatic symptom recognition and classification of MR images and improve the accuracy and efficiency of the diagnosis of lumbar intervertebral disc herniation (LDH), a method for lumbar intervertebral disc recognition and disease classification is proposed in this paper. The method mainly includes three steps: preprocessing, target segmentation, and symptom classification. Preprocessing is performed by noise reduction and interference removal methods for blurred images. The contour poles are used to determine the four points of the tail vertebra in order to reduce the wrong segmentation of the tail vertebra. A classification method based on five judgment indicators is proposed, which effectively improves the stability of disease diagnosis. The example verifies that the algorithm can accurately complete the target segmentation and the accuracy of symptom classification reaches the standard of professional doctors, which proves that the method has good robustness.

Arterial spin labeling of nasopharyngeal carcinoma shows early therapy response.

OBJECTIVE: This study aimed to determine the value of arterial spin labeling (ASL) perfusion imaging in assessing the early efficacy of chemoradiotherapy for nasopharyngeal carcinoma (NPC). METHODS: Fifty-five patients with locoregionally advanced NPC underwent conventional 3.0-T magnetic resonance imaging (MRI) and ASL before and after chemoradiotherapy (prescribed dose reached 40 Gy). Based on the response evaluation criteria for solid tumors (RECIST 1.1), the patients were divided into the partial response and stable disease groups. MRI re-examination was performed one month after chemoradiotherapy completion, and patients were divided into residual and non-residual groups. We investigated inter-group differences in ASL-based tumor blood flow (TBF) parameters (pre-treatment tumor blood flow, post-treatment tumor blood flow, and changes in tumor blood flow, i.e., Pre-TBF, Post-TBF, ΔTBF), correlation between TBF parameters and tumor atrophy rate, and value of TBF parameters in predicting sensitivity to chemoradiotherapy. RESULTS: There were differences in Pre-TBF, Post-TBF, and ΔTBF between the partial response and stable disease groups (p < 0.01). There were also differences in Pre-TBF and ΔTBF between the residual and non-residual groups (p < 0.01). Pre-TBF and ΔTBF were significantly correlated with the tumor atrophy rate; the correlation coefficients were 0.677 and 0.567, respectively (p < 0.01). Pre-TBF had high diagnostic efficacies in predicting sensitivity to chemoradiotherapy and residual tumors, with areas under the curve of 0.845 and 0.831, respectively. CONCLUSION: ASL permits a noninvasive approach to predicting the early efficacy of chemoradiotherapy for NPC.

Fluorescence and absorbance dual-mode immunoassay for detecting Ochratoxin A.

In this work, a simple dual-mode immunoassay for detecting Ochratoxin A (OTA) was developed by mixing G-quadruplex/N-methylmesoporphyrin IX (G4/NMM) and 3,3',5,5'-tetramethylbenzidine (TMB). The fluorescence of G4/NMM can be quenched by oxidized TMB (oxTMB) because the absorbance of oxTMB overlapped with the fluorescence emission of G4/NMM. In the absence of OTA, large amounts of oxTMB were formed with blue color and the fluorescence of G4/NMM was quenched. In the presence of OTA, the concentration of oxTMB was decreased, therefore the fluorescence of G4/NMM increased. The linear range of fluorescence immunoassay was 0.195-25 ng/mL, and the linear range of the absorbance immunoassay was 0.049-1.563 ng/mL. Thus, the linear range of this dual-mode immunoassay can be expanded to 0.049-25 ng/mL. Meanwhile, the new method showed good selectivity for OTA. Besides, the satisfactory recovery rates implied the new method had a potential value for practical sample detection.

Fluorescence determination of glyphosate based on a DNA-templated copper nanoparticle biosensor.

A rapid and convenient fluorescence glyphosate (GLYP) biosensor was developed based on DNA-templated copper nanoparticles (DNA-CuNPs). In the absence of GLYP, the DNA-CuNPs were formed through the reduction of Cu2+ by vitamin C (Vc). The DNA-CuNPs emitted intense fluorescence at 615 nm when being excited at 340 nm. In the presence of GLYP, GLYP can strongly chelate with Cu2+ by the phosphate and carboxyl groups to decrease the amount of free Cu2+. Due to the lack of free Cu2+, DNA-CuNPs cannot be formed, which caused the fluorescence to decrease. The whole detection process of this proposed GLYP biosensor can be completed within 14 min. Titration experiments showed that this biosensor had a linear relationship for GLYP in the range 1 to 18 µM with a limit of detection (LOD) of 0.47 µM. This biosensor showed obvious selectivity among other pesticides, even between GLYP and organophosphorus pesticides. This biosensor performed well for GLYP detection in real samples with recoveries of 88.0-104.0%.

A novel fluorescence method for detection of phosphate anions based on porphyrin metalation.

In this work, a novel fluorescence method for the detection of phosphate anions (PO43-) was developed based on porphyrin metalation. Through catalysis by G-quadruplex (G4), Cu2+ could insert into the porphyrins to quench their fluorescence. G4 simultaneously improved the fluorescence of the porphyrins but not that of Cu2+-porphyrin. In the absence of PO43-, the porphyrins were metallized by Cu2+, and no fluorescence was observed. In the presence of PO43-, PO43- could coordinate with Cu2+ to prevent porphyrin metalation. Free porphyrin could bind with G4 to emit strong fluorescence. By comparing four common porphyrins, we found that G4 had the greatest effect on increasing the fluorescence intensity of N-methylmesoporphyrin IX (NMM). Thus, NMM/G4 was chosen for the design of a biosensor. Under optimal experimental conditions, this method showed high sensitivity and satisfactory selectivity for PO43- with a detection limit of 44 nM in a linear range of 0.01-1.0 µM. The recovery experiments showed recovery rates of 93.75-106.00%, suggesting a great potential for measuring PO43- in real samples.

Highly sensitive biosensor based on aptamer and hybridization chain reaction for detection of cadmium ions.

In this work, a highly sensitive biosensor for detecting cadmium ions (Cd2+ ) was developed based on a Cd2+ -specific DNA aptamer and a hybridization chain reaction (HCR). The Cd2+ aptamer (named S0) was used to recognize Cd2+ and trigger the HCR. Without Cd2+ , S0 initiated the HCR to form long nicked dsDNA structures to quench the fluorescence. Then, Cd2+ could bind with S0 to block HCR to recover fluorescence. This biosensor had high sensitivity with a detection limit of 0.36 nM and a linear range from 0 to 10 nM. Moreover, it showed a satisfactory selectivity and recovery rates.

A double signal amplification strategy for sensitive detection of Hg2+ based on exonuclease III and PCR.

A double signal amplification method was developed for sensitive detection of Hg2+ based on exonuclease III (Exo III) and Polymerase Chain Reaction (PCR). In the presence of Hg2+, the ineffective primers could bind with helper DNA to form dsDNA by T-Hg(II)-T mismatch for the first signal amplification. Then, the ineffective primers were digested by Exo III to effective primers which initiate PCR reaction for the second signal amplification. This conversion from ineffective to effective primers for triggering PCR reaction has not been reported for the detection of Hg2+. Through the double signal amplification strategy, the sensitivity of this proposed method was significantly improved with the limit of detection 1.46 nM. With the specific T-Hg(II)-T recognition, the selectivity of this new method was satisfactory. And the recoveries were between 92.3 % and 109.0 %. These results suggested that the proposed method was reliable to detect Hg2+ in water samples.

A novel signal amplification biosensor for detection of Cd2+ based on asymmetric PCR.

In this work, a novel signal amplification biosensor was utilized to detect Cd2+ based on asymmetric PCR. In the presence of Cd2+, it can bind with Cd2+-aptamer C1 which caused the complementary strand C2 to be released from double-stranded DNA C1-C2. Because the single-stranded C1 cannot be hydrolyzed by Exo III, it can be used as a template to take part in asymmetric PCR reaction. In the absence of Cd2+, the C1-C2 was digested by Exo III and no PCR template was left. During the experiment, an interesting phenomenon was found that the asymmetric PCR can obtain higher level of fluorescent signal than that of symmetric PCR. To the best of our knowledge, this is the first report of using asymmetric PCR to detect Cd2+. Through the asymmetric PCR amplification strategy, this biosensor had a low detection limit (19.93 nM) and a wide linear range (0-500 nM). Meanwhile, this biosensor showed a satisfactory selectivity and recovery rate.