Towards Active Tracking of Beating Heart Motion in the Presence of Arrhythmia for Robotic Assisted Beating Heart Surgery

In robotic assisted beating heart surgery, the control architecture for heart motion tracking has stringent requirements in terms of bandwidth of the motion that needs to be tracked. In order to achieve sufficient tracking accuracy, feed-forward control algorithms, which rely on estimations of upcoming heart motion, have been proposed in the literature. However, performance of these feed-forward motion control algorithms under heart rhythm variations is an important concern. In their past work, the authors have demonstrated the effectiveness of a receding horizon model predictive control-based algorithm, which used generalized adaptive predictors, under constant and slowly varying heart rate conditions. This paper extends these studies to the case when the heart motion statistics change abruptly and significantly, such as during arrhythmias. A feasibility study is carried out to assess the motion tracking capabilities of the adaptive algorithms in the occurrence of arrhythmia during beating heart surgery. Specifically, the tracking performance of the algorithms is evaluated on prerecorded motion data, which is collected in vivo and includes heart rhythm irregularities. The algorithms are tested using both simulations and bench experiments on a three degree-of-freedom robotic test bed. They are also compared with a position-plus-derivative controller as well as a receding horizon model predictive controller that employs an extended Kalman filter algorithm for predicting future heart motion.     

Design,synthesis, and evaluation of novel 2-phenylpropionic acid derivatives as dual COX inhibitory-antibacterial agents

A series of 2-(4-substitutedmethylphenyl)propionic acid derivatives (6a–6m) were synthesized, characterized and evaluated for cyclooxygenase (COX) enzyme inhibitory and antimicrobial activity. Test compounds that exhibited good COX inhibition and antibacterial activity were further screened for their cytotoxicity and genotoxicity. Compounds 6h and 6l showed better COX-1 and COX-2 inhibition when compared to ibuprofen. Inhibition potency of these compounds against COX-2 was very close to that of nimesulide. The compounds 6d, 6h, 6l and 6m displayed promising antibacterial property when compared to chloramphenicol. However, the compound 6l was emerged as the best dual COX inhibitory-antibacterial agent in this study. The ADME prediction of the compounds revealed that they may have a good pharmacokinetic profile. Docking results of the compounds 6h and 6l with COX-1 (PDB ID: 1EQG) also exhibited a strong binding profile.

     

Some morphological and anatomical observations during alleviation of salinity (NaCI) stress on seed germination and seedling growth of barley by polyamines

In this work, the effects of polyamine (cadaverine, putrescine, spermidine, spermine) pretreatments on the germination of barley seeds, seedling growth under saline (NaCI) conditions and on leaf anatomy of the seedlings grown for 20 days in pots with perlite containing different concentrations of NaCI prepared with Hoagland solutions following the germination period of 7 days were studied. The inhibitive effect of salt on seed germination and seedling growth was alleviated in varying degrees, and dramatically, by polyamine pretreatments at the levels of NaCI studied; particularly with lower levels of salt, the control seeds were able to germinate with great difficulty. Also, the successes of these pretreatments continued, even decreased, with higher levels of NaCI such that the control seeds showed no germination. On the other hand, on the various parameters of leaf anatomy of barley seedlings, interactions between pretreatments of polyamine and salinity, with some of these being statistically important, were observed.