Design, Manufacturing and Control of an Advanced High-Precision Robotic System for Microsurgery

Microsurgeries like ophthalmic surgery confront many challenges like limited workspace and hand motion, steady hand movements, manipulating delicate thin tissues, and holding the instrument in place for a long time. New developments in robotically-assisted surgery can highly benefits this field and facilitate those complicated surgeries. Robotic eye surgery can save time, reduce surgical complications and inspire more delicate surgical procedures that cannot be done currently by surgeon’s hands. In this thesis work, the requirements for ophthalmic surgeries were studied and based on that a robotic system with 6 DOF is proposed and designed. This robotic system is capable of handling the position and orientation of the surgical instrument with theoretical accuracy of 10 μm. The design features a remote center of motion that defines the point of entry into the eye or patient’s body. The forward and inverse kinematics equations and workspace analysis of the robot is also discussed and presented. Six miniature DC motors with their PID controllers were installed on robot arms in order to run 6 DOF systems. Therefore, the dynamic behavior of a DC motor was studied and modeled and then the position and velocity transfer functions were derived and used to study the behavior of the system and also to manually tune the PID controller. The function of different elements of the control system including encoder, controller modules, Controller Area Network (CAN) and the controller software were discussed as well. The graphical user interface called EPOS Studio and performs as the motion controller is introduced and the way it organizes communications among the elements of the control system was described

Psychological stress has a higher rate of developing addictive behaviors compared to physical stress in rat offspring

Prenatal stress could have great influence on development of offspring and might alter cognitive function and other physiological processes of children. The current study was conducted to study the effect of physical or psychological prenatal stress on addictive and anxiety-like behavior of male and female offspring during their adolescence period (postnatal day (PND) 40). Adult female rats were exposed to physical (swimming) or psychological (observing another female rat swimming) stress from day six of gestation for 10 days. Male and female offspring were assayed for anxiety-like behavior, motor and balance function and morphine conditioned place preference using the open field, elevated plus maze (EPM), rotarod and wire grip assay and conditioned place preference. Offspring in both physical and psychological prenatal stress groups demonstrated significant increase in anxiety-like behavior in EPM paradigm, but no alterations were observed in motor and balance function of animals. Offspring in the psychological prenatal stress group had an increased preference for morphine in comparison to control and physical prenatal stress groups. Results of the current study demonstrated that animals exposed to psychological stress during fetal development are at a higher risk of developing addictive behaviors. Further research might elucidate the exact mechanisms involved to provide better preventive and therapeutic interventions

Assessment of heat shock protein (HSP60, HSP72, HSP90, and HSC70) expression in cultured limbal stem cells following air lifting

Objectives: The aim of this study is to create an ex vivo model to examine the expression of major heat-shock protein (HSP) families; HSP60, HSP72, and HSP90, and heat-shock cognate 70 (HCS70) at the mRNA and protein level in differentiating corneal cells from limbal stem cells (LSC) following air exposure. Methods: Limbal biopsies taken from cadaveric normal human limbus were cultivated as explants on human amniotic membrane (HAM) and plastic dish (PD)

Comparing Culture and Multiplex PCR Methods to Examine Fastidious Bacteria in Otitis Externa and Media

Ear infection or otitis is a generic term used to refer to ear infection or inflammation. The purpose of the present study was to compare culture and Multiplex PCR methods to identify Alloiococcus otitidis, Moraxella catarrhalis, and Haemophilus influenza as three fastidious pathogens causing otitis. 100 patients, who had the physician-confirmed infection of the external ear and otitis media, were randomly sampled. The samples were analyzed with culture and Multiplex PCR. None of the three bacteria were found in samples of otitis externa by culture or PCR. In the case of otitis media three isolates of Alloiococcus otitidis, one isolation of Moraxella catarrhalis, and three strains of Haemophilus influenza were found using culture method. In the case of otitis media three isolates of Alloiococcus otitidis, one isolation of Moraxella catarrhalis, and three strains of Haemophilus influenza were found using culture method, but the rate of these bacteria were 25, 11 and 28 isolates using Multiplex PCR. The Multiplex PCR method was found to be furthermost sensitive, truthful and reproducible screening method for detection of fastidious bacteria

Strategies for producing improved oxygen barrier materials appropriate for the food packaging sector

Flexible and transparent polymeric and bio-polymeric "super barrier" packaging materials have become increasingly important in recent years especially for oxygen-sensitive foods packaging. Different approaches and emerging technologies have been applied in order to improve oxygen barrier properties which can extend the shelf life and maintain the quality and freshness of food products during their determined shelf life. In this review, we summarize the diverse strategies for manufacturing improved oxygen barrier materials including: incorporation of nanoparticles into polymer matrix, fabrication of multilayer polymer, creation of new barrier methods such as development of crystals in polymer matrix, and cross-linking technique. The structure, preparation, and gas barrier properties of obtained polymers via mentioned approaches are discussed in general along with detailed examples drawn from the scientific literature