Composition Analysis of Sargassum Fusiforme in Different Marine Areas and Antioxidant Activity of Polysaccharides

Sargassum fusiforme is rich in a variety of nutrients and active substances, and is one of the important economic seaweeds in China. Its quality could be easily affected by environmental factors such as marine areas. To figure out the differences in nutritional composition of Sargassum fusiforme cultivated in different marine areas, this paper used Sargassum fusiforme cultivated in seven marine areas in Zhejiang Province as the research object, and determined the basic nutrients, amino acids and fatty acids using the National Food Safety Standard. The antioxidant activities of the seven Sargassum fusiforme polysaccharides were determined using DPPH· and ·OH scavenging as evaluation criteria, and the structural composition of seven kinds of Sargassum fusiforme polysaccharides were preliminarily analyzed. The results showed that, the moisture content of seven Sargassum fusiforme was highest, between (82.50±0.32) and (86.50±0.23) g/100 g. In addition to moisture content, the other main nutrient component was polysaccharide. The polysaccharide content of Sargassum fusiforme cultivated in No.7 marine area was the highest (P<0.05), which was 2.51 g/100 g. The fat content of Sargassum fusiforme of each marine area was relatively low, which was (0.30±0.01)~(0.40±0.01) g/100 g, indicating that Sargassum fusiforme was a kind of typically low-fat food. The amino acid content of Sargassum fusiforme varied greatly and the EAAI (Essential Amino Acid Index) values of Sargassum fusiforme in each marine area were all more than 0.9, indicating that Sargassum fusiforme in the seven marine areas were all high-quality protein sources. Furthermore, the amino acid composition ratios of Sargassum fusiforme cultivated in No.2 and No.6 marine areas were reasonable, which were closer to the ideal protein model recommended by WHO/FAO in 1937. A total of eight fatty acids were detected in Sargassum fusiforme from seven marine areas. Except for Sargassum fusiforme cultivated in No.2 marine area, the rest were mainly polyunsaturated fatty acids. The heavy metal content of Sargassum fusiforme complied with the requirements of in National food safety standard-Maximum levels of contaminants in foods (GB 2762-2017). The contents of Ca and K in Sargassum fusiforme cultivated in No.4 marine area were (131.44±6.36) mg/100 g and (1687.63±28.14) mg/100 g, respectively, which were good sources of Ca and K. The polysaccharide structures of Sargassum fusiforme in each marine area were similar, all of which contained sulfate groups and had the activity of scavenging ·OH and DPPH·. Among them, the polysaccharide of Sargassum fusiforme cultivated in No.5 marine area had the highest antioxidant activity, and the IC50 of scavenging ·OH and DPPH· were 0.534 and 0.236 mg/mL, respectively. This study laid a certain foundation for the scientific breeding, processing and quality grade evaluation of Sargassum fusiforme

One-Step Preparation of High Performance TiO 2 /CNT/CQD Nanocomposites Bactericidal Coating with Ultrasonic Radiation

© 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).As an environmental semiconductor material, TiO2 has important applications in the fields of environmental protection and water treatment. The preparation of P25 particles into nano-functional material films with a high specific surface area has always been a bottleneck limiting its large-scale application. In this paper, a one-step method of preparing TiO2 nanocomposites by doping carbon nanotube (CNT) and carbon quantum dots (CQD) with tetrabutyltitanate and P25 TiO2 under ultrasonic radiation is proposed to synthesize a novel antifouling material, which both eliminates the bacterium of Escherichia coli and shows good photoelectric properties, indicating a great value for the industrial promotion of TiO2/CNT. This mesoporous composite exhibits a high specific surface area of 78.07 M2/g (BET) and a tested pore width range within 10–120 nm. The surface morphology of this composite is characterized by TEM and the microstructure is characterized through XRD. This preparation method can fabricate P25 particles into a nano-functional material film with a high specific surface area at a very low cost.Peer reviewe

A Novel Position Compensation Scheme for Cable-Pulley Mechanisms Used in Laparoscopic Surgical Robots

The tendon driven mechanism using a cable and pulley to transmit power is adopted by many surgical robots. However, backlash hysteresis objectively exists in cable-pulley mechanisms, and this nonlinear problem is a great challenge in precise position control during the surgical procedure. Previous studies mainly focused on the transmission characteristics of the cable-driven system and constructed transmission models under particular assumptions to solve nonlinear problems. However, these approaches are limited because the modeling process is complex and the transmission models lack general applicability. This paper presents a novel position compensation control scheme to reduce the impact of backlash hysteresis on the positioning accuracy of surgical robots’ end-effectors. In this paper, a position compensation scheme using a support vector machine based on feedforward control is presented to reduce the position tracking error. To validate the proposed approach, experimental validations are conducted on our cable-pulley system and comparative experiments are carried out. The results show remarkable improvements in the performance of reducing the positioning error for the use of the proposed scheme

An Integrated Method of Biomechanics Modeling for Pelvic Bone and Surrounding Soft Tissues

The pelvis and its surrounding soft tissues create a complicated mechanical environment that greatly affects the success of fixing broken pelvic bones with surgical navigation systems and/or surgical robots. However, the modeling of the pelvic structure with the more complex surrounding soft tissues has not been considered in the current literature. The study developed an integrated finite element model of the pelvis, which includes bone and surrounding soft tissues, and verified it through experiments. Results from the experiments showed that including soft tissue in the model reduced stress and strain on the pelvis compared to when it was not included. The stress and strain distribution during pelvic loading was similar to what is typically seen in research studies and more accurate in modeling the pelvis. Additionally, the correlation with the experimental results from the predecessor’s study was strong (R2 = 0.9627). The results suggest that the integrated model established in this study, which includes surrounding soft tissues, can enhance the comprehension of the complex biomechanics of the pelvis and potentially advance clinical interventions and treatments for pelvic injuries

Synthesis and phototoxicity of isomeric 7,9-diglutathione pyrrole adducts: Formation of reactive oxygen species and induction of lipid peroxidation

Pyrrolizidine alkaloids (PAs) are hepatotoxic, genotoxic, and carcinogenic in experimental animals. Because of their widespread distribution in the world, PA-containing plants are probably the most common poisonous plants affecting livestock, wildlife, and humans. Upon metabolism, PAs generate reactive dehydro-PAs and other pyrrolic metabolites that lead to toxicity. Dehydro-PAs are known to react with glutathione (GSH) to form 7-GSH-(+/−)-6,7-dihydro-7-hydroxy-1-hydroxymethyl-5H-pyrrolizine (7-GS-DHP) in vivo and in vitro and 7,9-diGS-DHP in vitro. To date, the phototoxicity of GS-DHP adducts has not been well studied. In this study, we synthesized 7-GS-DHP, a tentatively assigned 9-GS-DHP, and two enantiomeric 7,9-diGS-DHP adducts by reaction of dehydromonocrotaline with GSH. The two 7,9-diGS-DHPs were separated by high performance liquid chromatography (HPLC) and their structures were characterized by 1H nuclear magnetic resonance (NMR) and 1H–1H correlation spectroscopy (COSY) NMR spectral analysis. Photoirradiation of 7-GS-DHP, 9-GS-DHP, and the two 7,9-diGS-DHPs as well as dehydromonocrotaline, dehydroheliotrine, and the 7-R enantiomer of DHP (DHR), by UVA light at 0 J/cm2, 14 J/cm2, and 35 J/cm2 in the presence of a lipid, methyl linoleate, all resulted in lipid peroxidation in a light dose-responsive manner. The levels of lipid peroxidation induced by the two isomeric 7,9-diGS-DHPs were significantly higher than that by 7-GS-DHP and 9-GS-DHP. When 7,9-diGS-DHP was irradiated in the presence of sodium azide (NaN3), the level of lipid peroxidation decreased; lipid peroxidation was enhanced when methanol was replaced by deuterated methanol. These results suggest that singlet oxygen is a product induced by the irradiation of 7,9-diGS-DHP. When irradiated in the presence of superoxide dismutase (SOD), the level of lipid peroxidation decreased, indicating that lipid peroxidation is also mediated by superoxide. These results indicate that lipid peroxidation is mediated by reactive oxygen species (ROS). These results suggest that 7,9-diGS-DHPs are phototoxic, generating lipid peroxidation mediated by ROS

Genome-Wide Characterization and Comparative Analysis of MYB Transcription Factors in Ganoderma Species

Numerous studies in plants have shown the vital roles of MYB transcription factors in signal transduction, developmental regulation, biotic/abiotic stress responses and secondary metabolism regulation. However, less is known about the functions of MYBs in Ganoderma. In this study, five medicinal macrofungi of genus Ganoderma were subjected to a genome-wide comparative analysis of MYB genes. A total of 75 MYB genes were identified and classified into four types: 1R-MYBs (52), 2R-MYBs (19), 3R-MYBs (2) and 4R-MYBs (2). Gene structure analysis revealed varying exon numbers (3-14) and intron lengths (7-1058 bp), and noncanonical GC-AG introns were detected in G. lucidum and G. sinense. In a phylogenetic analysis, 69 out of 75 MYB genes were clustered into 15 subgroups, and both single-copy orthologous genes and duplicated genes were identified. The promoters of the MYB genes harbored multiple cis-elements, and specific genes were co-expressed with the G. lucidum MYB genes, indicating the potential roles of these MYB genes in stress response, development and metabolism. This comprehensive and systematic study of MYB family members provides a reference and solid foundation for further functional analysis of MYB genes in Ganoderma species

Electrochemical Coupled Analysis of a Micro Piezo-Driven Focusing Mechanism

In order to improve the response speed and output force of the camera focusing mechanism, the authors proposed a novelty micro focusing mechanism based on piezoelectric driving, which has the characteristics of rapid response, high precision positioning and large displacement focusing. In this paper, the operating principle of the proposed focusing mechanism is presented. Using the piezoelectric output characteristic, the movable tooth drive theory and the screw drive theory, the electromechanical coupling mechanical model and equations of the piezoelectric focusing mechanism are established. Through MATLAB simulation, the output characteristics of the piezoelectric focusing mechanism are calculated. The results indicate that the maximum thrust force of the lens and the maximum output torque of the movable tooth drive for the piezoelectric focusing mechanism are 562.5 N and 1.16 Nm, respectively. Furthermore, the driving voltage directly affects the output performance of the piezoelectric focusing mechanism. These results can be utilized both to optimize the dimensions and improve the overall performance of the piezo-driven focusing mechanism

Motion planning framework based on dual-agent DDPG method for dual-arm robots guided by human joint angle constraints

IntroductionReinforcement learning has been widely used in robot motion planning. However, for multi-step complex tasks of dual-arm robots, the trajectory planning method based on reinforcement learning still has some problems, such as ample exploration space, long training time, and uncontrollable training process. Based on the dual-agent depth deterministic strategy gradient (DADDPG) algorithm, this study proposes a motion planning framework constrained by the human joint angle, simultaneously realizing the humanization of learning content and learning style. It quickly plans the coordinated trajectory of dual-arm for complex multi-step tasks.MethodsThe proposed framework mainly includes two parts: one is the modeling of human joint angle constraints. The joint angle is calculated from the human arm motion data measured by the inertial measurement unit (IMU) by establishing a human-robot dual-arm kinematic mapping model. Then, the joint angle range constraints are extracted from multiple groups of demonstration data and expressed as inequalities. Second, the segmented reward function is designed. The human joint angle constraint guides the exploratory learning process of the reinforcement learning method in the form of step reward. Therefore, the exploration space is reduced, the training speed is accelerated, and the learning process is controllable to a certain extent.Results and discussionThe effectiveness of the framework was verified in the gym simulation environment of the Baxter robot's reach-grasp-align task. The results show that in this framework, human experience knowledge has a significant impact on the guidance of learning, and this method can more quickly plan the coordinated trajectory of dual-arm for multi-step tasks