We previously demonstrated the protective effect of inducible heat shock protein 70 (Hsp70) against gamma radiation. Herein, we extend our studies on the possible role of Hsp70 to ionizing radiation-induced cell cycle regulation. The growth rate of inducible hsp70-transfected cells was 2-3 hours slower than that of control cells. Flow cytometric analysis of cells at G1 phase synchronized by serum starvation also showed the growth delay in the Hsp70-overexpressing cells. In addition, reduced cyclin D1 and Cdc2 levels and increased dephosphorylated phosphoretinoblastoma (pRb) were observed in inducible hsp70-transfected cells, which were probably responsible for the reduction of cell growth. To find out if inducible Hsp70-mediated growth delay affected radiation-induced cell cycle regulation, flow cytometric and molecular analyses of cell cycle regulatory proteins and their kinase were performed. The radiationinduced G2/M arrest was found to be inhibited by Hsp70 overexpression and reduced p21Waf induction and its kinase activity by radiation in the Hsp70-transfected cells. In addition, radiation-induced cyclin A or B1 expressions together with their kinase activities were also inhibited by inducible Hsp70, which represented reduced mitotic cell death. Indeed, hsp70 transfectants showed less induction of radiation-induced apoptosis. When treated with nocodazole, radiationinduced mitotic arrest was inhibited by inducible Hsp70. These results strongly suggested that inducible Hsp70 modified growth delay (increased G1 phase) and reduced G2/M phase arrest, subsequently resulting in inhibition of radiationinduced cell death.

In this study, the design of an magnetorheological elastomer flexible coupling whose torsional stiffness can be controlled by an embedded magnetic field generator is proposed. It is designed to minimize the torsional vibration transmission between shafts adaptively to the dynamic disturbance. The coupling insert is composed of magnetorheological elastomer which is a smart material whose stiffness can be controlled by an external magnetic field. This article also proposes a compact magnetic field generator which can be fitted inside the coupling hubs, to control the torsional stiffness of the magnetorheological elastomer. The finite element method was used to design and estimate the dynamic stiffness variation of the magnetorheological elastomer coupling due to the applied magnetic field and disturbance frequency. Also, torsional vibration experiments were conducted to validate the performance of the proposed magnetorheological elastomer coupling. Results showed that it can adaptively tune in a range of frequencies between 16.8 and 23.5 Hz and has 95.7% stiffness variation under magnetic field of 150mT. The proposed system is expected to achieve a higher MRE effect with a softer base matrix.

We report on a new morphological crystal engineering technique introducing in situ tailor-made additives for organic molecular crystals. In the crystal growing process, phenolic substrate molecules are transformed to in situ tailor-made phenolate additives by adding a small amount of base, without any additional synthetic and purification processes. To demonstrate the in situ tailor-made additive technique, phenolic OH1 (2-(3-(4-hydroxystyryl)-5,5-dimethylcyclohex-2-enylidene)­malononitrile) crystal, exhibiting highly efficient nonlinear optical and terahertz generation responses, is chosen as substrate crystal. The in situ tailor-made additive molecules containing a phenolate group exhibit considerably different stereoselective interactions with specific crystal surfaces of phenolic substrate OH1 crystals compared to analogous conventional tailor-made additives. The stereospecific interactions result in a morphological change of the grown OH1 crystal more optimal for photonic applications. To show the usefulness of the in situ tailor-made additive technique for applications as well as for fundamental research, newly created parallel surfaces in rectangular rod-shaped OH1 crystals grown in the presence of tailor-made additive are used to demonstrate the THz wave generation by optical rectification, in which one single OH1 crystal can be used in two different optical configurations. Therefore, the in situ tailor-made additive technique is very useful for morphological crystal engineering in fundamental research and various practical applications.

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