CONTROL SYSTEM OF CRYOGENIC PLANT FOR SUPERCONDUCTING CYCLOTRON AT VECC

Cryogenic Plant of Variable Energy Cyclotron Centre<br />consists of two Helium refrigerators (250W and 415W @<br />4.5K), valve box with sub-cooler and associated sub<br />systems like pure gas storage, helium purifier and impure<br />gas recovery etc. The system also consists of 3.1K liters<br />of liquid Nitrogen (LN2) storage and delivery system. The<br />plant is designed to cater the cryogenic requirements of<br />the Superconducting Cyclotron. The control system is<br />fully automated and does not require any human<br />intervention once it is started. EPICS (Experimental<br />Physics and Industrial Control System) architecture has<br />been adopted to design the Supervisory control and data<br />acquisition (SCADA) module. The EPICS Input Output<br />Controller (IOC) communicates with four Programmable<br />Logic Controllers (PLCs) over Ethernet based control<br />LAN to control/monitor 618 numbers of field Inputs/<br />Outputs(I/O). The plant is running very reliably round the<br />clock, however, the historical data trending of important<br />parameters during plant operation has been integrated to<br />the system for plant maintenance and easy diagnosis. The<br />400 KVA UPS with 10 minutes back up time have been<br />installed to keep the cryogenic system running with one<br />160KW cycle compressor during utility power<br />interruptions

Niacin esters of chalcones with tumor-selective properties

Novel series of niacin esters of chalcones 2, 4 and 6 were designed as antineoplastic agents that have the potential to release the chemoprotectant niacin. These enones are cytotoxic to human CD4(+ )T-lymphocyte Molt 4/C8 and CEM and murine leukemia L1210 cells. Quantitative structure-activity relationship (QSAR) studies of the biodata in series 4 revealed that cytotoxic potency was enhanced by placing electron-repelling groups in one of the aryl rings. The compounds are lethal to HL-60, HSC-2, HSC-3 and HSC-4 neoplasms but less toxic to nonmalignant hepatocyte growth factor, hematopoietic progenitor cell and human periodontal ligament fibroblast cells. Hence, the compounds display tumor-selective toxicity. These chalcones are well tolerated in mice and no overt toxicity was noted. The results establish that in general the compounds in series 2, 4 and 6 have positive characteristics which warrant further studies.status: publishe

6-Benzylidene-2-[4-(pyridin-3-ylcarboxy)benzylidene]cyclohexanones: A novel cluster of tumour-selective cytotoxins

Novel cytotoxins 3-5 containing the 1,5-diaryl-3-oxo-1,4-pentadienyl pharmacophore are disclosed. The compounds in series 3 and 5 have the potential to liberate niacin which may reduce some of the side effects of antineoplastic compounds. 3a-c emerged as the most potent cytotoxic compounds with IC50 values in the low micromolar range against human Molt4/C8 and CEM CD4(+) T-lymphocytes as well as murine L1210 leukemia cells. QSAR studies revealed that cytotoxic potencies were negatively correlated with the magnitude of the Hammett sigma values of the aryl substituents. The compounds 3a-e displayed tumour-selective toxicity against human HL-60, HSC-2, HSC-3 and HSC-4 neoplasms as compared to human HGF, HPC and HPLF nonmalignant cells. A representative potent compound 3a caused PARP1 cleavage and G0/G1 cell cycle arrest in HSC-2 cells. These compounds are well tolerated in mice at doses up to and including 300mg/kg of the compounds and no mortalities were noted after 4h. The stability studies undertaken did not reveal that a representative compound 3a underwent hydrolysis to the related phenol 2a. Some guidelines for further analog development of the novel esters 3 were made.status: publishe