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To ensure litchi fruit yield and quality, reasonable blooming period management such as flower thinning is required during the early flowering period. A combination of the number of litchi flowers and their density map can provide a reference for blooming period management decisions during the flowering period. Flowering intensity is currently largely estimated manually by humans observing the trees in the orchard. Although some automatic computer vision systems have been proposed for estimating flowering intensity, their overall performance is inadequate to meet current flower-thinning needs, and these systems are weak in some situations such as in varying environments and when the target object has a low-density distribution. With male litchi flowers as the research object, the goal of this study was to design a method for calculating the number of flowers. By using an image of the male litchi flower as input to a multicolumn convolutional neural network, a final density map and the number of flowers were generated. Experimental results using a self-constructed male litchi flower dataset demonstrated the feasibility of outputting a density map and flower count. The flower number was estimated from the model with a mean absolute error (MAE) that reached 16.29 and a mean square error (MSE) reaching 25.40 on the test set, which was better than counting by target detection. The proposed method can be used to perform time-saving analyses to help estimate yield and implement follow-up orchard management, and it demonstrates the potential of using density maps as outputs for estimating flowering intensity. [ABSTRACT FROM AUTHOR]

Since gas sensor drift is a main limitation for the application of an electronic nose, and a reference standard is necessary for shelf management of litchi fruit, a modified mean deviation threshold function based on fast Fourier transform (MDFF-FFT) for electronic nose drift elimination and a new concept the rest storage life (RSL) for litchi fruit shelf situation evaluation have been constructed in this study. Three commonly used threshold acquisition methods, unbiased estimator, fixed threshold, and mini-max principle were evaluated to instead of selecting threshold value randomly for present MDFF-FFT. A PEN3 portable electronic nose was applied to recognize the RSL of litchi during storage across room temperature (RT), refrigerator environment (RE) and controlled-atmosphere (CA) environments. Linear discriminant analysis (LDA), probabilistic neural network (PNN), and partial least squares regression (PLSR) were used to compare the RSL classification effect, recognition accuracy, and predict ability of litchi stored in the three environments based on electronic nose with the drift elimination of different threshold acquisition methods using MDTF-FFT. The results showed that an electronic nose has the potential to recognize the RSL of litchi stored in different environments. Unbiased estimator method can provide better threshold than other threshold acquisition methods for MDTF-FFT. After drift elimination by unbiased estimator method combined with MDTF-FFT, litchi RSL can be classified, recognized and predicted by electronic nose effectively, the accuracy of which was higher than control (no drift elimination) and drift elimination with other methods. [ABSTRACT FROM AUTHOR]

A mutant human factor IX with arginine at 338 residual changed to alanine (hFIXR338A) by site-directed mutagenesis was introduced into AAV vectors, and a recombinant adeno-associated viral vector containing hFIXR338A, prepared by rHSV/AAV hybrid helper virus system, was directly introduced to the hind leg muscle of factor IX knock out mice. The expression and the biological activity of human factor IX mutant, hFIXR338A, and the immune response against it in the treated mice were assayed and detected. The results showed that (i) the high-level expression of human factor IX mutant protein, hFIXR338A, has been detected in rAAV-hFIXR338A treated hemophilia B mice and lasted more than 15 weeks; (ii) the clotting activity of hFIXR338A in plasma is 34.2%±5.23%, which is remarkably higher than that of (14.27% ± 3.4%) of wild type hFIX treated mice in the activated partial thromboplastin assay; (iii) immune response against factor IX R338A was absent, with no factor IX mutant protein (hFIXR338A) inhibitors development in the treated mice; and (iv) no local or systemic side-effects and toxicity associated with the gene transfer were found. It demonstrated the potential use of treating hemophilia B by recombinant adeno-associated viral vectors with mutant hFIXR338A gene, an alternative strategy for hemophilia B gene therapy to wild-type human factor IX. [ABSTRACT FROM AUTHOR]

Presents a study which constructed a series of adeno-associated viral vectors containing a mutation of human factor IX (hFIXR338A) with different regulation elements. Use of the vectors to transduce cell lines; Materials used; In vitro mutagenesis and DNA sequence analysis of hFIXR338A.