Rank-driven salp swarm algorithm with orthogonal opposition-based learning for global optimization.

Salp swarm algorithm (SSA) is a relatively new and straightforward swarm-based meta-heuristic optimization algorithm, which is inspired by the flocking behavior of salps when foraging and navigating in oceans. Although SSA is very competitive, it suffers from some limitations including unbalanced exploration and exploitation operation, slow convergence. Therefore, this study presents an improved version of SSA, called OOSSA, to enhance the comprehensive performance of the basic method. In preference, a new opposition-based learning strategy based on optical lens imaging principle is proposed, and combined with the orthogonal experimental design, an orthogonal lens opposition-based learning technique is designed to help the population jump out of a local optimum. Next, the scheme of adaptively adjusting the number of leaders is embraced to boost the global exploration capability and improve the convergence speed. Also, a dynamic learning strategy is applied to the canonical methodology to improve the exploitation capability. To confirm the efficacy of the proposed OOSSA, this paper uses 26 standard mathematical optimization functions with various features to test the method. Alongside, the performance of the proposed methodology is validated by Wilcoxon signed-rank and Friedman statistical tests. Additionally, three well-known engineering optimization problems and unknown parameters extraction issue of photovoltaic model are applied to check the ability of the OOSA algorithm to obtain solutions to intractable real-world problems. The experimental results reveal that the developed OOSSA is significantly superior to the standard SSA, currently popular SSA-based algorithms, and other state-of-the-artmeta-heuristic algorithms for solving numerical optimization, real-world engineering optimization, and photovoltaic model parameter extraction problems. Finally, an OOSSA-based path planning approach is developed for creating the shortest obstacle-free route for autonomous mobile robots. Our introduced method is compared with several successful swarm-based metaheuristic techniques in five maps, and the comparative results indicate that the suggested approach can generate the shortest collision-free trajectory as compared to other peers.

Lipid Polymer Hybrid Nanomaterials for mRNA Delivery.

INTRODUCTION: In the past decade, messenger RNA (mRNA) has been extensively explored in a wide variety of biomedical applications. However, efficient delivery of mRNA is still one of the key challenges for its broad applications in the clinic. Recently, lipid polymer hybrid nanoparticles (LPNs) are evolving as a promising class of biomaterials for RNA delivery, which integrate the physicochemical properties of both lipids and polymers. We previously developed an N1,N3,N5-tris(2-aminoethyl)benzene-1,3,5-tricarboxamide (TT) derived lipid-like nanomaterial (TT3-LLN) which was capable of effectively delivering multiple types of mRNA. In order to further improve the delivery efficiency of TT3-LLN, in this study, we focused on studying the effects of incorporating different polymers on establishing LPNs and aimed to develop an optimized lipid polymer hybrid nanomaterial for efficient mRNA delivery. METHODS: We incorporated a series of biodegradable and biocompatible polymer materials into the formulation of TT3-LLNs to develop LPNs. mRNA delivery efficiency of different LPNs were evaluated and a systematic orthogonal optimization was further carried out. RESULTS: Our data indicate that PLGA4 (MW 24,000-38,000 g/mol) dramatically increased delivery efficiency of TT3-LLNs in comparison to other polymers. Further optimization identified PLGA4-7 LPNs (PLGA:mRNA=9:1, mass ratio; TT3:DOPE:Cholesterol:DMG-PEG2000=25:25:45:0.75, molar ratio) as a lead formulation, which displayed significantly enhanced delivery of two types of mRNA in three different human cell lines as compared with TT3-LLNs. CONCLUSIONS: Results from this study potentially provide new insights into developing LPNs for mRNA based therapeutics.

Fabrication of Defect-Free Cellulose Acetate Hollow Fibers by Optimization of Spinning Parameters.

Spinning of cellulose acetate (CA) with the additive polyvinylpyrrolidone (PVP) in N-methyl-2-pyrrolidone (NMP) solvent under different conditions was investigated. The spinning parameters of air gap, bore fluid composition, flow rate of bore fluid, and quench bath temperature were optimized based on the orthogonal experiment design (OED) method and multivariate analysis. FTIR and scanning electron microscopy were used to characterize the membrane structure and morphology. Based on the conjoint analysis in Statistical Product and Service Solutions (SPSS) software, the importance of these parameters was identified as: air gap > bore fluid composition > flow rate of bore fluid > quench bath temperature. The optimal spinning condition with the bore fluid (water + NMP (85%)), air gap (25 mm), flow rate of bore fluid (40% of dope rate), and temperature of quench bath (50 °C) was identified to make high PVP content, symmetric cross-section and highly cross-linked CA hollow fibers. The results can be used to guide the spinning of defect-free CA hollow fiber membranes with desired structures and properties as carbon membrane precursors.

Antibacterial Activity of Polygonum Orientale Extracts Against Clavibacter Michiganensis subsp. michiganensis, the Agent of Bacterial Canker of Tomato Disease

Abstract Clavibacter michiganensis subsp. michiganensis (Cmm), which is a Gram positive bacterium, causes the bacterial canker of tomato disease. The purpose of the study was to evaluate the antibacterial activity of Polygonum orientale extracts against Cmm. In this study, firstly, effects of three extracting parameters (extractive time, extractive temperature, and solid to liquid ratio) of orthogonal experiment design L27 (313) were conducted. Secondly, survival rate was determined and inhibition zone of Cmm rescued post-stress was monitored. Finally, extracellular OD260nm value, extracellular protein content, conformational structure of membrane protein, extracellular alkaline phosphatase (AKP) activity, and ATPase activity were measured to investigate the antibacterial mechanism. Results of orthogonal experiment revealed that extractive time and extractive temperature had highly significant (P<0.01) effects on the antibacterial activity of P. orientale extracts. The optimum conditions were as follows: 10h of extractive time, 60°C of extractive temperature, and 1:20 (g:mL) of solid to liquid ratio. This study also demonstrated that the living cells of each sample from survival rate test had almost no resistance or adaptability, and rescued Cmm cells were much easier to be inhibited by P. orientale extracts. The results of antibacterial mechanism indicated that cell membrane and cell wall of Cmm were seriously damaged by P. orientale extracts, and P. orientale extracts reduced the intracellular ATPase activity dramatically. All these findings suggested that P. orientale extracts had a strong antibacterial activity to inhibit Cmm, and could be used for the ecological management of the bacterial canker of tomato disease.

Applied orthogonal experiment design for the optimum microwave-assisted extraction conditions of polysaccharides from Rhodiolae Radix.

An experiment on polysaccharides from Rhodiolae Radix (PRR) extraction was carried out using microwave-assisted extraction (MAE) method with an objective to establishing the optimum MAE conditions of PRR. Single factor experiments were performed to determine the appropriate range of extraction conditions, and the optimum conditions were obtained using orthogonal experiment design. The results showed that the optimum MAE conditions of PRR were as follows: solid-liquid ratio of 1:45 g/mL, irradiation power of 480 W, and irradiation time of 8 min, while extraction yield of PRR was 3.24 %.