Hybrid improved capuchin search algorithm for plant image thresholding.

With the development and wider application of meta-heuristic optimization algorithms, researchers increasingly apply them to threshold optimization of multi-level image segmentation. This paper explores the performance and effects of Capuchin Search Algorithm (CAPSA) in threshold optimization. To solve problems of uneven distribution in the initial population of Capuchin Search Algorithm, low levels of global search performance and premature falling into local optima, this paper proposes an improved Capuchin Search Algorithm (ICAPSA) through a multi-strategy approach. ICAPSA uses chaotic opposite-based learning strategy to initialize the positions of individual capuchins, and improve the quality of the initial population. In the iterative position updating process, Levy Flight disturbance strategy is introduced to balance the global optimization and local exploitation of the algorithm. Finally, taking Kapur as the objective function, this paper applies ICAPSA to multi-level thresholding in the plant images, and compares its segmentation effects with the original CAPSA, the Fuzzy Artificial Bee Colony algorithm (FABC), the Differential Coyote Optimization Algorithm (DCOA), the Modified Whale Optimization Algorithm (MWOA) and Improved Satin Bowerbird Optimization Algorithm (ISBO). Through comparison, it is found that ICAPSA demonstrates superior segmentation effect, both in the visual effects of image segmentation and in data comparison.

Application of Improved Satin Bowerbird Optimizer in Image Segmentation.

Aiming at the problems of low optimization accuracy and slow convergence speed of Satin Bowerbird Optimizer (SBO), an improved Satin Bowerbird Optimizer (ISBO) based on chaotic initialization and Cauchy mutation strategy is proposed. In order to improve the value of the proposed algorithm in engineering and practical applications, we apply it to the segmentation of medical and plant images. To improve the optimization accuracy, convergence speed and pertinence of the initial population, the population is initialized by introducing the Logistic chaotic map. To avoid the algorithm falling into local optimum (prematurity), the search performance of the algorithm is improved through Cauchy mutation strategy. Based on extensive visual and quantitative data analysis, this paper conducts a comparative analysis of the ISBO with the SBO, the fuzzy Gray Wolf Optimizer (FGWO), and the Fuzzy Coyote Optimization Algorithm (FCOA). The results show that the ISBO achieves better segmentation effects in both medical and plant disease images.

Modified Discrete Grey Wolf Optimizer Algorithm for Multilevel Image Thresholding.

The computation of image segmentation has become more complicated with the increasing number of thresholds, and the option and application of the thresholds in image thresholding fields have become an NP problem at the same time. The paper puts forward the modified discrete grey wolf optimizer algorithm (MDGWO), which improves on the optimal solution updating mechanism of the search agent by the weights. Taking Kapur's entropy as the optimized function and based on the discreteness of threshold in image segmentation, the paper firstly discretizes the grey wolf optimizer (GWO) and then proposes a new attack strategy by using the weight coefficient to replace the search formula for optimal solution used in the original algorithm. The experimental results show that MDGWO can search out the optimal thresholds efficiently and precisely, which are very close to the result examined by exhaustive searches. In comparison with the electromagnetism optimization (EMO), the differential evolution (DE), the Artifical Bee Colony (ABC), and the classical GWO, it is concluded that MDGWO has advantages over the latter four in terms of image segmentation quality and objective function values and their stability.

Expression of biologically active human insulin-like growth factor 1 in Arabidopsis thaliana seeds via oleosin fusion technology.

Novel protein expression in plant-based systems has become an important tool in producing and studying therapeutic proteins. Among many plant-based systems developed so far, oleosin fusion technology is one of the most cost-effective and convenient methods. In this study, an important therapeutic protein, human insulin-like growth factor 1 (hIGF-1), was expressed in Arabidopsis thaliana seeds via this technology. The plant bias codon usage-optimized hIGF-1 gene was fused to the C-terminal of A. thaliana 18.5 kDa oleosin gene, and the fusion gene driven by an oleosin promoter was transferred into A. thaliana ecotype Col-0. The accumulation of oleosin-hIGF-1 fusion protein in transgenic seeds was up to 0.75% of total seed protein (TSP) and the expression level of hIGF-1 was 0.17% of the TSP, which was eight times higher than previously reported using other plant-based hIGF-1 production systems. The biological activity of the hIGF-1 as an oleosin-hIGF-1 fusion protein in vitro was demonstrated by using human SH-SY5Y neuroblastoma cells.

XRCC1 Arg399Gln, Arg194Trp and Arg280His polymorphisms in breast cancer risk: a meta-analysis.

X-ray repair cross-complementing group 1 (XRCC1) plays an important role in base excision and single-strand break repair, as a scaffold protein that brings together proteins of the DNA repair complex, and appears to be a candidate for cancer risk. However, studies on the association between polymorphisms in this protein and cancer have yielded conflicting results. We performed a meta-analysis to investigate the association between the breast cancer and the XRCC1 polymorphisms Arg194Trp (9411 cases and 9783 controls), Arg399Gln (22 481 cases and 23 905 controls) and Arg280His (6062 cases and 5864 controls) in different inheritance models. Our analysis suggested that Arg399Gln was associated with a trend of increased breast cancer risk when using both dominant [odds ratio (OR) = 1.06, 95% confidence interval (CI): 1.00-1.13] and recessive models (OR = 1.12, 95% CI: 1.02-1.23) to analyse the data. In ethnic subgroups and using recessive model analysis: Arg399Gln increased breast cancer risk in Asians (OR = 1.26, 95% CI: 0.96-1.64) and Africans (OR = 1.80, 95% CI: 0.97-3.32), and also while only slightly increasing the breast cancer risk in Caucasians (OR = 1.08, 95% CI: 0.95-1.22). However, Arg194Trp (recessive model, OR = 0.95, 95% CI: 0.75-1.20) and Arg280His (recessive model, OR = 1.28, 95% CI: 0.64-2.55) did not appear to be risk factors for breast cancer. Larger scale primary studies are required to further evaluate the interaction of XRCC1 polymorphisms and breast cancer risk in specific populations.

[Modification, expression and bioactivity analysis of hK-Fc fusion protein].

To prolong serum half-life of human kallikrein (hK) and enhance its secretion rate, we modified hK gene and constructed a new form of recombinant hK protein (hK'-Fc). We amplified hK gene and Fc sequence, replaced the signal peptide of hK gene with murine signal peptide, constructed native expression plasmid of pcDNA-hK-Fc and modified expression plasmid of pcDNA-hK'-Fc, then transfected to CHO cells respectively. After the stable cell lines were screened, we compared the secretion rate between native fusion protein and modified fusion protein, purified fusion protein through Protein A+G affinity chromatography column and investigated the bioactivity of fusion protein. The results showed that recombinant vectors encoding fusion protein hK-Fc and hK'-Fc were constructed successfully; CHO cell lines stably secreting fusion protein were obtained, the yield is higher than 11 mg/L; Secretion rate was enhanced by 5-10 times after the signal peptide of fusion protein was modified; Fusion protein has enzymatic activity in vitro. The above results could promote the following researches on serum half-life of the fusion protein and develop a new stroke medicine with better clinical efficacy.