Investigation of Rice Bran Derived Anti-cancer Pentapeptide for Mechanistic Potency in Breast Cancer Cell Models

Bioactive peptides derived from food sources with anti-proliferative properties against cancer have drawn more attention in recent years. A pentapeptide derived from rice bran has shown anti-proliferative propertiesagainst human breast cancer cells. The objective of this study was to investigate the mechanistic action of the pentapeptide-induced apoptosis in breast cancer cell models (MCF-7 and MDA-MB-231). The growth inhibition activity of the pentapeptide was evaluated by MTS[3-(4,5-dimethylthiazol-2-yl)-5-(3- arboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt] assayand trypan blue assay in a dose- and time-dependent manner. The apoptotic properties of pentapeptide-induced apoptosis on cancerous breast cells were evaluated by morphological changes, DNA fragmentation, and caspases-3/7, -8,and -9 activities. The levels of molecular targets (p53, COX-2, TNF-α, Fas, Bax, Bcl-2, and ErbB-2) were evaluated by enzyme-linked immunosorbent assay (ELISA) kits. Pentapeptide showed growth inhibition activities on MCF-7 and MDA-MB-231 cells. Apoptotic features including morphological changes,DNA fragmentation, and caspases activation were observed in both cells lines after pentapeptide treatment. Decreased levels of COX-2, Bcl-2, and ErbB-2 and increased levels of p53, TNF-α, Fas, and Bax expression were detected after cells exposed to pentapeptide from 72 to 96 hr. The results suggest that the pentapeptide inhibits growth of human breast cancer cells by introducing apoptosis through a caspase-dependent pathway. The pentapeptide amplifies the death signal by down-regulating the expression of ErbB-2 in both cell lines and COX-2 in ER (Estrogen Receptor)-positive MCF-7 cells. This study provides insight on the molecular mechanism of action of the pentapeptide against breast cancer cells. After further animal and human clinic trial, the pentapeptide has the potentiality to be analternative strategy to current anti-cancer drugs

Protection challenges in future converter-dominated power systems : investigation and quantification using a novel flexible modelling and hardware testing platform

Error on title page – year of award is 2023.The research work presented in this thesis addresses anticipated (and documented) protection challenges that will be introduced by the domination of power electronics interfaces in future power systems. A flexible and programmable voltage source converter (VSC) model with controllable fault response has been developed and this is tested using realistic network data (including transmission lines and the corresponding power flow/fault level data) from the GB transmission network, provided by National Grid ESO (the research project sponsor). The results of tests, where a range of variations to the converter controllers’ fault-responses have been implemented (e.g. to reflect different detection and initial converter response delays, output current ramp rates and magnitudes), are presented and analysed. The simulated voltage and current waveforms are injected into actual protection relays using secondary injection amplifiers. The responses of the relays are recorded and a number of issues are highlighted, particularly with respect to the response of distance protection. It is shown that, when the system is dominated by converter-interfaced sources (especially where the sources are modelled as being unable to provide “fast” and “high” fault currents, which is typically the case for actual converter systems), the responses of traditional distance protection systems (and other systems relying on measurement of current magnitude) could be delayed, lose discrimination, e.g. by tripping with a zone 2 delay for a zone 1 fault, or may be completely unable to detect faults at certain locations within the system. Based on the test results, potential solutions are then presented relating to changes to relay algorithms and/or the requirements for converters in terms of behaviour during faults. The outcomes of the work will be of interest to grid code developers (publications arising from this work have already been referred to by ENTSO-E guidance document for national implementation for network codes on grid connection [1]), transmission network operators, other researchers and protection/converter manufacturers. An overview of future work, relating to comprehensive studies (using injection and the developed system/converter models) of a range of faults/ infeeds/ converter mixes with a wide range of protection relays including distance and unit-type, and development of a standard commissioning testing method of protection relays under future power system scenarios that are dominated by converters, is included in the concluding section. This will assist in the investigation and resolution of issues associated with protection performance in future converter-dominated power systems.The research work presented in this thesis addresses anticipated (and documented) protection challenges that will be introduced by the domination of power electronics interfaces in future power systems. A flexible and programmable voltage source converter (VSC) model with controllable fault response has been developed and this is tested using realistic network data (including transmission lines and the corresponding power flow/fault level data) from the GB transmission network, provided by National Grid ESO (the research project sponsor). The results of tests, where a range of variations to the converter controllers’ fault-responses have been implemented (e.g. to reflect different detection and initial converter response delays, output current ramp rates and magnitudes), are presented and analysed. The simulated voltage and current waveforms are injected into actual protection relays using secondary injection amplifiers. The responses of the relays are recorded and a number of issues are highlighted, particularly with respect to the response of distance protection. It is shown that, when the system is dominated by converter-interfaced sources (especially where the sources are modelled as being unable to provide “fast” and “high” fault currents, which is typically the case for actual converter systems), the responses of traditional distance protection systems (and other systems relying on measurement of current magnitude) could be delayed, lose discrimination, e.g. by tripping with a zone 2 delay for a zone 1 fault, or may be completely unable to detect faults at certain locations within the system. Based on the test results, potential solutions are then presented relating to changes to relay algorithms and/or the requirements for converters in terms of behaviour during faults. The outcomes of the work will be of interest to grid code developers (publications arising from this work have already been referred to by ENTSO-E guidance document for national implementation for network codes on grid connection [1]), transmission network operators, other researchers and protection/converter manufacturers. An overview of future work, relating to comprehensive studies (using injection and the developed system/converter models) of a range of faults/ infeeds/ converter mixes with a wide range of protection relays including distance and unit-type, and development of a standard commissioning testing method of protection relays under future power system scenarios that are dominated by converters, is included in the concluding section. This will assist in the investigation and resolution of issues associated with protection performance in future converter-dominated power systems

Sampling-based 3-D Line-of-Sight PWA Model Predictive Control for Autonomous Rendezvous and Docking with a Tumbling Target

In this paper, a model predictive control (MPC) framework is employed to realize autonomous rendezvous and docking (AR&D) with a tumbling target, using the piecewise affine (PWA) model of the 3-D line-of-sight (LOS) dynamics and Euler attitude dynamics. Consider the error between the predictions obtained by the approximate linear model and the actual states of nonlinear dynamics, a sampling-based PWA MPC is proposed to sample the predictions in the closer neighborhood of the actual states. Besides, novel constructions of constraints are presented to reduce the on-board computation cost and time-delay. Furthermore, a singularity-free strategy is provided to realize crossing the singularity of angle states smoothly. Then, the mission is achieved by continuous 6-DOF pose (position and attitude) tracking of the target's docking port, with the coupling between the position and attitude of the target's docking port is taken into account. Finally, numerical results are presented to demonstrate the above theories

Correspondence of D. melanogaster and C. elegans developmental stages revealed by alternative splicing characteristics of conserved exons

Illustration of RNA-seq datasets. Illustration of RNA-seq datasets of fly and worm from modEncode. (PDF 1020 kb