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Purpose The purpose of this paper is to propose a novel jump control method based on Two Mass Spring Damp Inverted Pendulum (TMS-DIP) model, which makes the third generation of hydraulic driven wheel-legged robot prototype (WLR-3P) achieve stable jumping. Design/methodology/approach First, according to the configuration of the WLR, a TMS-DIP model is proposed to simplify the dynamic model of the robot. Then the jumping process is divided into four stages: thrust, ascent, descent and compression, and each stage is modeled and solved independently based on TMS-DIP model. Through WLR-3P kinematics, the trajectory of the upper and lower centroids of the TMS-DIP model can be mapped to the joint space of the robot. The corresponding control strategies are proposed for jumping height, landing buffer, jumping attitude and robotic balance, so as to realize the stable jump control of the WLR. Findings The TMS-DIP model proposed in this paper can simplify the WLR dynamic model and provide a simple and effective tool for the jumping trajectory planning of the robot. The proposed approach is suitable for hydraulic WLR jumping control. The performance of the proposed wheel-legged jump method was verified by experiments on WLR-3P. Originality/value This work provides an effective model (TMS-DIP) for the jump control of WLR-3P. The results showed that the number of landing shock (twice) and the pitch angle fluctuation range (0.44 rad) of center of mass of the jump control method based on TMS-DIP model are smaller than those based on spring-loaded inverted pendulum model. Therefore, the TMS-DIP model makes the jumping process of WLR more stable and gentler.

An efficient method for the enzymatic synthesis of cephalexin (CEX) from 7-amino-3-deacetoxycephalosporanic acid (7-ADCA) and d-phenylglycine methyl ester (PGME) using immobilized penicillin G acylase (IPGA) as catalyst in a suspension aqueous solution system was developed, where the reactant 7-ADCA and product CEX are mainly present as solid particles. The effects of key factors on the enzymatic synthesis were investigated. Results showed that continuous feeding of PGME was more efficient for the synthesis of CEX than the batch mode. Under the optimized conditions, the maximum 7-ADCA conversion ratio of 99.3% and productivity of 200 mmol/L/H were achieved, both of which are much superior to the homogeneous aqueous solution system. Besides, IPGA still retained 95.4% of its initial activity after 10 cycles of enzymatic synthesis, indicating the excellent stability of this approach. The developed approach shows great potential for the industrial production of CEX via an enzyme-based route.

Enzymatic catalysis has been recognized as a green alternative to classical chemical route for synthesis of cephalexin (CEX). However, its industrial practice has been severely limited by the low productivity due to the low solubility of 7-amino-3-deacetoxycephalosporanic acid (7-ADCA) and high hydrolysis of D-phenylglycine methyl ester (PGME). In this work, the enhanced dissolution of 7-ADCA in the presence of PGME for efficient enzymatic synthesis of CEX was investigated. Results showed that the solubility of 7-ADCA in water could be improved by PGME. Moreover, supersaturated solution of 7-ADCA could be created in the presence of PGME by a pH shift strategy. The supersaturated solution of 7-ADCA possess good stability, which could be explained in terms of the inhibition of 7-ADCA precipitation due to the presence of PGME. The interaction between 7-ADCA and PGME is explored by spectroscopic determination and DFT analysis and the mechanism of enhanced dissolution of 7-ADCA in the presence of PGME is discussed and proposed. The feasibility of supersaturated solution of 7-ADCA for the enzymatic synthesis of CEX is evaluated. It was demonstrated that high conversion ratio (> 95.0%) and productivity (> 240.0 mmol/L/h) was obtained under a wide range of reaction conditions, indicating that the supersaturated solution system was highly superior to conventional homogeneous solution system. The information obtained in this work will be helpful to industrial production of CEX via enzymatic route.

This paper presents the force control strategies and a kind of compliance control strategies of the hydraulic- driven unit (HDU) in the legged robots. The model of HDU is established and the transfer function of the HDU force control system is given. The analysis of the force control strategies is introduced according to the characteristic of the HDU system. Based on the force control strategy called velocity feedback control strategy which performs the best, the virtual model control strategy which is a kind of compliance control strategy is presented to enhance the adaptability of the legged robot. Finally, the experiments are taken on the HDU experiment platform to test the performance of the force control strategies and the compliance control strategy. The landing buffer experiments are taken on the single leg robot to verify the effectiveness of the compliance control strategy. In the landing buffer experiments, the impact force of the single leg robot's knee HDU is about 0.33 time of what it is without the compliance control strategy while landing.

This paper presents a vertical jumping trajectory planning and landing buffer control methods that enable a hydraulic driven single legged robot to execute load-bearing take-off and stable landing motions. After a brief description of the robot, the kinematics and dynamics models of HSLR are established based on the actual structure of the robot. Then the paper describes the details of jumping trajectory planning method based on spring loaded inverted pendulum (SLIP) model, which can realize vertical jump control with a desired height. Moreover, landing buffer strategy based on single legged virtual model is presented to protect robots from the impact damage. Finally, the experimental results show that the proposed method for HSLR can achieve vertical jump to 0.2m as well as a stable landing buffer performance.

Colorectal cancer is one of the most common malignant tumors in the digestive system, and in China its incidence is rising in recent years. The FAM83D family with sequence similarity 83, member D is associated with the occurrence and development of various cancers. However, in human colorectal cancer, the biological function of FAM83D and its molecular mechanism are still little known. In our study, we found that FAM83D mRNA expression level was markedly up-regulated in colorectal cancerous tissues when compared with that of adjacent normal colon tissues. We also found that the protein and mRNA expression levels of FAM83D are dramatically increased in human colorectal cancer cell lines, including Caco-2, RKO, DLD-1, HT-29, LoVo, SW480, and HCT116, especially in SW480 and HCT116 cells, when compared with that of human normal colon epithelial cell line (NCM460). Next, in HCT116 and SW480 cells, the biological function of FAM83D was examined. FAM83D-knockdown notably inhibited cell proliferation and colony formation. Cell apoptosis was promoted by FAM83D knockdown. In addition, FAM83D siRNA decreased cell migration and invasion. Moreover, FAM83D knockdown up-regulated the protein expression level of F-box and WD repeat domain-containing 7 (FBXW7), but diminished the Notch1 protein expression level. It also found that FBXW7 siRNA reverses the suppressive effect of FAM83D knockdown on Notch1 protein expression. Notch1 overexpression reversed the effect of FAM83D knockdown on colorectal cancer cell proliferation, cell migration and invasion. In conclusion, FAM83D knockdown promoted colorectal cancer cell apoptosis, inhibited cell proliferation, cell migration and invasion, which might be associated with inhibiting the FBXW7/Notch1 signal pathway. Our findings indicated that FAM83D is a promising molecular target for colorectal cancer treatment.