Fruits hidden by green: an improved YOLOV8n for detection of young citrus in lush citrus trees.

In order to address the challenges of inefficiency and insufficient accuracy in the manual identification of young citrus fruits during thinning processes, this study proposes a detection methodology using the you only look once for complex backgrounds of young citrus fruits (YCCB-YOLO) approach. The method first constructs a dataset containing images of young citrus fruits in a real orchard environment. To improve the detection accuracy while maintaining the computational efficiency, the study reconstructs the detection head and backbone network using pointwise convolution (PWonv) lightweight network, which reduces the complexity of the model without affecting the performance. In addition, the ability of the model to accurately detect young citrus fruits in complex backgrounds is enhanced by integrating the fusion attention mechanism. Meanwhile, the simplified spatial pyramid pooling fast-large kernel separated attention (SimSPPF-LSKA) feature pyramid was introduced to further enhance the multi-feature extraction capability of the model. Finally, the Adam optimization function was used to strengthen the nonlinear representation and feature extraction ability of the model. The experimental results show that the model achieves 91.79% precision (P), 92.75% recall (R), and 97.32% mean average precision (mAP)on the test set, which were improved by 1.33%, 2.24%, and 1.73%, respectively, compared with the original model, and the size of the model is only 5.4 MB. This study could meet the performance requirements for citrus fruit identification, which provides technical support for fruit thinning.

Quantitation of phlorizin and phloretin using an ultra high performance liquid chromatography-electrospray ionization tandem mass spectrometric method.

A sensitive and selective ultra high performance liquid chromatography-tandem mass spectrometric (UHPLC-MS/MS) method for the determination of phlorizin and phloretin in human plasma has been firstly developed. Samples were prepared after protein precipitation and analyzed on a C18 column interfaced with a triple quadrupole tandem mass spectrometer. Negative electrospray ionization was employed as the ionization source. The mobile phase consisted of acetonitrile-water (0.02% formic acid), using a gradient procedure. The analytes and internal standard dihydroquercetin were both detected by use of multiple reaction monitoring mode. The method was linear in the concentration range of 2.5-1000.0 ng/mL. The lower limit of quantification (LLOQ) was 2.5 ng/mL. The intra- and inter-day relative standard deviation across three validation runs over the entire concentration range was less than 9.2%. The accuracy determined at three concentrations was within ± 7.3% in terms of relative error. The total run time was 12.0 min. This assay offers advantages in terms of expediency, and suitability for the analysis of phlorizin and phloretin in various biological fluids.

Antioxidant isolated from Schisandra propinqua (Wall. ) Baill

Schisandra propinqua (Wall.) Baill.(Schisandraceae) is widely used as a Chinese folk medicine. In this study, activity-guided fractionation of the ethanol extract from the stem of Schisandra propinqua led to the isolation of four extracts. Subsequently, a neolignan 4,4-di(4-hydroxy-3-methoxyphenly)-2,3-dimethylbutanol was isolated from the EtOAc part of the stem of Schisandra propinqua, the free radical scavenging activities of which were researched in vitro. The present work demonstrated that extracts and pure compound possessed scavenging activities to DPPH, superoxide anions and hydroxy radical, and could depress lipid peroxidation reaction induced by oxygen radical produced by the Fe2+/cysteine system in vitro. This suggests that the traditional application of Schisandra propinqua in China may be related to its antioxidant activities, and the EtOAc part of the stems of Schisandra propinqua can be utilized as an effective source of antioxidants.