Proposed Design Model of Single use Bioreactor for Mesenchymal Stem Cells Proliferation

AbstractBioreactor, the womb for human stem cells, plays a vital role in enhancing its proliferation under controlled environment. Stem cells have the potential to differentiate and replicate it-self to further grow human tissues and organs. Bioreactor nurtures stem cells by providing nutritious environment and peerless oxygen flow inside the cell bag without obstructing the sheer force of the fluid or gas bubbles. The present paper unveils the design and development of bioreactor using the gyrator motion mechanism. This high functional bioreactor provides automation system that enhances the environment and serves excellent nutrient distribution to exceed cell growth through oxygen transfer and better mixing. One of the best characteristic of this bioreactor is that it requires no cleaning or sterilization as it is disposable. Compared to other bioreactors such as spinner flask type, rotating-wall type and the hollow fibre type, the proposed bioreactor is more convenient, easy to operate and maintain with more flexibility. Proposed bioreactor system operates in conjunction with mechanism of external gyrating motion that uses gravity in a natural way to make the flow circular inside it. The simultaneous mixing motion base is extremely suitable to grow stem cells. This bioreactor can be easily placed in an incubator and further addition or sampling is viable without the use of laminar flow cabinet

A Method of Calculating Motion Error in a Linear Motion Bearing Stage

We report a method of calculating the motion error of a linear motion bearing stage. The transfer function method, which exploits reaction forces of individual bearings, is effective for estimating motion errors; however, it requires the rail-form errors. This is not suitable for a linear motion bearing stage because obtaining the rail-form errors is not straightforward. In the method described here, we use the straightness errors of a bearing block to calculate the reaction forces on the bearing block. The reaction forces were compared with those of the transfer function method. Parallelism errors between two rails were considered, and the motion errors of the linear motion bearing stage were measured and compared with the results of the calculations, revealing good agreement

An Energy Efficient Turning Process for Hardened Material with Multi-Criteria Optimization

This paper presents a systematic procedure for the optimization of machining parameters such as cutting speed, feed rate, nose radius, edge radius, and rake angle to reduce specific material removal energy and improve energy efficiency in the hard turning of AISI 4140 steel. A simulation approach was applied in conjunction with the design of experiment (DOE), mathematical approximation with a meta-model to develop specific energy as well as an energy efficiency model in terms of cutting parameters. A hybrid approach that combines the Multi-Objective Particle Swarm Optimization (MOPSO) and the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) using entropy weights was adopted to determine the best solution from the Pareto set. The results showed that energy efficiency could be improved by 11%, whereas specific energy decreased by approximately 15% compared to a non-optimal case. Therefore, this study is expected as a contribution to making the turning process of hardened materials greener and more efficient

Deep Learning Methods for Universal MISO Beamforming

This letter studies deep learning (DL) approaches to optimize beamforming vectors in downlink multi-user multi-antenna systems that can be universally applied to arbitrarily given transmit power limitation at a base station. We exploit the sum power budget as side information so that deep neural networks (DNNs) can effectively learn the impact of the power constraint in the beamforming optimization. Consequently, a single training process is sufficient for the proposed universal DL approach, whereas conventional methods need to train multiple DNNs for all possible power budget levels. Numerical results demonstrate the effectiveness of the proposed DL methods over existing schemes.Comment: to appear in IEEE Wireless Communications Letters (5 pages, 3 figures, 2 tables