Toxic effects of heavy metals Pb and Cd on mulberry (Morus alba L.) seedling leaves: Photosynthetic function and reactive oxygen species (ROS) metabolism responses.

To explore the mechanism of how lead (Pb) and cadmium (Cd) stress affects photosynthesis of mulberry (Morus alba L.), we looked at the effects of different concentrations of Pb and Cd stress (at 100 and 200 µmol L-1), which are two heavy metal elements, on leaf chlorophyll (Chl), photosynthesis gas exchange, Chl fluorescence, and reactive oxygen species (ROS) metabolism in mulberry leaves. The results showed that higher concentrations of Pb and Cd reduced leaf Chl content, especially in Chl a where content was more sensitive than in Chl b. Under Pb and Cd stress, the photosynthetic carbon assimilation capacity of mulberry leaves was reduced, which was a consequence of combined limitations of stomatal and non-stomatal factors. The main non-stomatal factors were decreased photosystem II (PSII) and photosystem I (PSI) activity and carboxylation efficiency (CE). Damage to the donor side of the PSII reaction center was greater than the acceptor side. After being treated with 100 µmol L-1 of Pb and Cd, mulberry leaves continued to be able to dissipate excess excitation energy by starting non-photochemical quenching (NPQ), but when Pb and Cd concentrations were increased to 200 µmol L-1, the protection mechanism that depends on NPQ was impaired. Excessive excitation energy from chloroplasts promoted a great increase of ROS, such as superoxide anion (O2•-) and H2O2. Moreover, under high Pb and Cd stress, superoxide dismutase (SOD) and ascorbate peroxidase (APX) were also inhibited to some extent, and excessive ROS also resulted in a significantly higher degree of oxidative damage. Compared with Cd, the effect of Pb stress at the same concentration level displayed a significantly lower impact on Chl content, photosynthetic carbon assimilation, and stomatal conductance. Meanwhile, Pb stress mainly damaged activity of the oxygen-evolving complex (OEC) located on PSII donor side, but it reduced the electronic pressure on the PSII acceptor side and PSI. Furthermore, under Pb stress, the NPQ, SOD, and APX activity were all significantly higher than those under Cd stress. Thus under Pb stress, the degree of photoinhibition and oxidative damage of PSII and PSI in mulberry leaves were significantly lower than under Cd stress.

Physiological and proteomic responses of reactive oxygen species metabolism and antioxidant machinery in mulberry (Morus alba L.) seedling leaves to NaCl and NaHCO3 stress.

In this paper, the effects of 100 mM NaCl and NaHCO3 stress on reactive oxygen species (ROS) and physiological and proteomic aspects of ROS metabolism in mulberry seedling leaves were studied. The results showed that NaCl stress had little effect on photosynthesis and respiration of mulberry seedling leaves. Superoxide dismutase (SOD) activity and the expression of related proteins in leaves increased by varying degrees, and accumulation of superoxide anion (O2·-) not observed. Under NaHCO3 stress, photosynthesis and respiration were significantly inhibited, while the rate of O2·- production rate and H2O2 content increased. The activity of catalase (CAT) and the expression of CAT (W9RJ43) increased under NaCl stress. In response to NaHCO3 stress, the activity and expression of CAT were significantly decreased, but the ability of H2O2 scavenging of peroxidase (POD) was enhanced. The ascorbic acid-glutathione (AsA-GSH) cycle in mulberry seedling leaves was enhancement in both NaCl and NaHCO3 stress. The expression of 2-Cys peroxiredoxin BAS1 (2-Cys Prx BAS1), together with thioredoxin F (TrxF), thioredoxin O1 (TrxO1), thioredoxin-like protein CITRX (Trx CITRX), and thioredoxin-like protein CDSP32 (Trx CDSP32) were significantly increased under NaCl stress. Under NaHCO3 stress, the expression of the electron donor of ferredoxin-thioredoxin reductase (FTR), together with Trx-related proteins, such as thioredoxin M (TrxM), thioredoxin M4 (TrxM4), thioredoxin X (TrxX), TrxF, and Trx CSDP32 were significantly decreased, suggesting that the thioredoxin-peroxiredoxin (Trx-Prx) pathway's function of scavenging H2O2 of in mulberry seedling leaves was inhibited. Taken together, under NaCl stress, excessive production of O2·- mulberry seedlings leaves was inhibited, and H2O2 was effectively scavenged by CAT, AsA-GSH cycle and Trx-Prx pathway. Under NaHCO3 stress, despite the enhanced functions of POD and AsA-GSH cycle, the scavenging of O2·- by SOD was not effective, and that of H2O2 by CAT and Trx-Prx pathway were inhibited; and in turn, the oxidative damage to mulberry seedling leaves could not be reduced.

Develepment of Hand Function Rehabilitation Evaluation and Training System Based on Virtual Reality Technol-ogy / 中国康复理论与实践

Objective To develop a system for hand function evaluation and training based on virtual reality. Methods 5DT Data Glove 5 Ultra, Visual Studio 2010 were integrated as the development environment and DirectX 9.0 as components, and the system was developed based on the MFC programming framework. Results and Conclusion The system can assess the fingers function, recognise gestures and can be used as a 3D environment for virtual training, which may guide the patients to take the training actively.

Design of Balance Function Telerehabilitation System Based on C/S / 生物医学工程学杂志

This article shows a new design of telerehabilitation system for balance function assessment and training in our laboratory. The system is based on C/S network architecture, and realizes the telecommunication through socket network communication technology. It implements the teletransmission of training data and assessment report of sit-down and stand-up, online communication between doctors and patients, and doctors'management of patient information. This system realizes remote evaluation and telerehabilitation of patients, and brings great convenience for the patients.

Research on measuring the velocity and displacement of the coxa and knee based on video image processing / 生物医学工程学杂志

Based on repeated experiments as well as continuous researching and improving, an efficient scheme to measure velocity and displacement of the coxa and knee movements based on video image processing technique is presented in this paper. The scheme performed precise and real-time quantitative measurements of 2D velocity or displacement of the coxa and knee using a video camera mounted on one side of the healing and training beds. The beds were based on simplified pinhole projection model. In addition, we used a special-designed auxiliary calibration target, composed by 24 circle points uniformly located on two concentric circles and two straight rods which can rotate freely along the concentric center within the vertical plane, to do the measurements. Experiments carried out in our laboratory showed that the proposed scheme could basically satisfy the requirements about precision and processing speed of such kind of system, and would be very suitable to be applied to smart evaluation/training and healing system for muscles/balance function disability as an advanced and intuitional helping method.

Dynamic modeling and simulating of squatting-standing action of human body / 生物医学工程学杂志

It is very difficult for stroke patients to complete the action of squatting-standing because their equilibrium function ability has been seriously declined. It was necessary, therefore, to do a deep research on the action of human squatting-standing and to set up an accurate model and simulation. In our modeling research, the movements of upper limbs and head was neglected, and a seven-segment model was developed to establish the coordinate system of human squatting-standing action. It calculated the knee joint moment and hip joint moment during squatting and standing by utilizing Lagrange method, and then simulated this mathematical model by utilizing Matlab. Geometric model of human squatting-standing was developed and simulated in ADAMS which proved that the established Lagrange model was reasonable. It would also provide significant theoretical references for further study and development of squatting-standing rehabilitation training equipment.

Design and realization of training methods based on sit-to-stand balance ability training apparatus / 生物医学工程学杂志

In this research, a new set of training methods was created and put into practice to train the body's sit-to-stand balancing ability, and controlling ability of body's gravity centre of patients with cerebrovascular diseases. It contains a series of motion trainings, including sitting position training, standing position training, sit-to-stand training and game training, etc. There is also a series of trainings of feedback included in this set of methods, such as internal feedback, external feedback, bandwidth feedback, conclusive feedback, visual feedback, acoustical feedback and so on. The trainings resulted in better controlling ability of body's centre of gravity in the sit-to-stand process of patients after a period of training. It indicated that these targeted-designed trainings, especially the feedback trainings, could effectively help the under-trained patients to have a better knowledge of their current situation, and in turn to have a better knowledge of which aspects they should take more training to achieve a better therapeutic effect.

Research on video measuring method of knee joint angle based on cross ratio invariability / 生物医学工程学杂志

With an un-calibrated camera a new method is proposed in this paper to measure dynamically the bending angle of knee-joint based on cross ratio invariability. Firstly, by video image processing technique, we detected 25 circular objectives distributed in the aided measurement tool and determined their geometric centers in the video frame respectively. Then we further computed the extending direction of thigh and shank by detecting position of two rectangular targets tied on them. Finally, using of the principle of cross ratio invariability in Projection Geometry, we could realize real-time dynamic measurement of the bending angle of knee-joint based on the method. Experiments have proved that the measurement precision of the introduced approach could satisfy basic requirements of clinical applications.