Repair Technologies Of Mechanical Drive Steam Turbines For Catastrophic Damage.

LecturePg. 15-24Mechanical drive steam turbines play an important role as core equipment in petrochemical plants, and these turbines are protected for safe operation by an antioverspeed trip device, as well as other monitoring and protection systems. However, in some cases a turbine will suffer severe mechanical damage due to improper operation or failure to activate the protection system as a result of human error. For urgent plant recovery and to minimize the duration of risky operation with no spare rotor, a damaged turbine has to be repaired in as short a time as possible. This paper introduces actual experiences in repairing and reviving catastrophically damaged turbine rotors through special welding procedures, based on element test to find the optimized welding condition, detailed strength calculations to confirm the integrity, and heat transfer analysis for proper heat treatment process conditions. These basic procedures are discussed to show useful data. The revived rotor of the extraction condensing turbine was placed back into the casing and operated. The turbine was uniquely modified in order to balance the required amount of power and minimize the repair time, to restart the plant as quickly as possible. The case study for this optimization is discussed by showing thermodynamic calculations, performance, and repair schedules. Root cause analysis for the process of the catastrophic failure is explained, for the integrated control system governing the control and operation positioner systems

4-Methylumebelliferone Enhances Radiosensitizing Effects of Radioresistant Oral Squamous Cell Carcinoma Cells via Hyaluronan Synthase 3 Suppression

Radioresistant (RR) cells are poor prognostic factors for tumor recurrence and metastasis after radiotherapy. The hyaluronan (HA) synthesis inhibitor, 4-methylumbelliferone (4-MU), shows anti-tumor and anti-metastatic effects through suppressing HA synthase (HAS) expression in various cancer cells. We previously reported that the administration of 4-MU with X-ray irradiation enhanced radiosensitization. However, an effective sensitizer for radioresistant (RR) cells is yet to be established, and it is unknown whether 4-MU exerts radiosensitizing effects on RR cells. We investigated the radiosensitizing effects of 4-MU in RR cell models. This study revealed that 4-MU enhanced intracellular oxidative stress and suppressed the expression of cluster-of-differentiation (CD)-44 and cancer stem cell (CSC)-like phenotypes. Interestingly, eliminating extracellular HA using HA-degrading enzymes did not cause radiosensitization, whereas HAS3 knockdown using siRNA showed similar effects as 4-MU treatment. These results suggest that 4-MU treatment enhances radiosensitization of RR cells through enhancing oxidative stress and suppressing the CSC-like phenotype. Furthermore, the radiosensitizing mechanisms of 4-MU may involve HAS3 or intracellular HA synthesized by HAS3

Development of drug screening system with nanoimprinting 3D culture to provide effective drugs in vivo and the accompanying PET probes for therapy monitoring

Anti-cancer drug development typically utilizes high-throughput screening with two-dimensional (2D) cell culture. However, 2D culture induces cellular characteristics different from tumours in vivo, resulting in inefficient drug development. In this study, we developed an innovative high-throughput screening system using nanoimprinting 3D culture to simulate in vivo conditions, thereby accurately predicting effective drugs in vivo and the accompanying PET probes for therapy monitoring. Methods: HT29 cells were cultured in 3D using nano-culture plates (NCPs) (96-wells, SCIVAX), in which nanoscale square grid patterns were printed on transparent synthetic-resinous bases with the nanoimprinting technique (Yoshii et al. 2011 Biomaterials). In vitro drug screening was performed with the SCADS inhibitor kit I, which contains vehicle control, 16 existing clinically-used antitumor agents, and 79 promising molecular targeted drugs against cancer. In vivo therapeutic effect of the drugs selected by screening was tested using HT29 tumor-bearing mice. PET probe uptake after treatment with the selected drug was also tested with 3D culture and tumor-bearing mice, using 2-fluoro-2-deoxy-D-glucose (FDG), methionine, acetic acid, 3\u27-fluoro 3\u27-deoxythymidine (FLT), and 4\u27-thiothymidine (4-DST). Results: Nanoimprinting 3D screening more efficiently selected drugs that effectively inhibited cancer growth in vivo as compared to conventional 2D culture. Pattern of PET probe uptake after treatment in 3D culture was similar to that in in vivo tumors. Conclusions: Nanoimprinting 3D screening can be a useful tool to efficiently select effective drugs and the accompanying PET probes, which would accelerate drug development and help to propose suitable therapy monitoring method.The Society of Nuclear Medicine (SNM) annual meeting 201

High-throughput screening with nanoimprinting 3D culture for efficient drug development by mimicking the tumor environment

Anti-cancer drug development typically utilizes high-throughput screening with two-dimensional (2D) cell culture. However, 2D culture induces cellular characteristics different from tumors in vivo, resulting in inefficient drug development. Here, we report an innovative high-throughput screening system using nanoimprinting 3D culture to simulate in vivo conditions, thereby facilitating efficient drug development. We demonstrated that cell line-based nanoimprinting 3D screening can more efficiently select drugs that effectively inhibit cancer growth in vivo as compared to 2D culture. Metabolic responses after treatment were assessed using positron emission tomography (PET) probes, and revealed similar characteristics between the 3D spheroids and in vivo tumors. Further, we developed an advanced method to adopt cancer cells from patient tumor tissues for high-throughput drug screening with nanoimprinting 3D culture, which we termed Cancer tissue-Originated Uniformed Spheroid Assay (COUSA). This system identified drugs that were effective in xenografts of the original patient tumors. Nanoimprinting 3D spheroids showed low permeability and formation of hypoxic regions inside, similar to in vivo tumors. Collectively, the nanoimprinting 3D culture provides easy-handling high-throughput drug screening system, which allows for efficient drug development by mimicking the tumor environment. The COUSA system could be a useful platform for drug development with patient cancer cells