INCREASED EXPRESSION OF c-myc GENE

High levels of c-myc mRNA were observed in two human tumor cell lines, a giant cell carcinoma of the lung (C-Lu99) and a colon cancer (C1). The increased expression of c-myc in these cell lines, which was comparable with those in cell lines in which the c-myc gene is amplified, was not due to gene amplification. Run-on transcription revealed that the transcriptional rate of the c-myc gene was greatly increased in these cell lines

Turning of BN free-machining steel

金沢大学理工研究域機械工学系This paper deals with the machinability of BN (Boron Nitride) free-machining steel in turning. Tested work materials were plane carbon steel JIS S45C and BN free-machining steel. The JIS S45C used as the standard. The tool wear in turning BN free-machining steel was smaller than that in turning standard steel. BN free-machining steel showed slightly lower cutting temperature and smaller cutting force to compare with standard steel at the tested cutting speeds. At the tool wear region of P grade carbide tool after turning BN free-machining steel at high cutting speed, Al and N were detected as a layer. It is thought that one of the main reasons of outstanding machinability of BN free-machining steel is the deposited layer containing Al and N acts as diffusion barrier at the tool-chip interface. In turning larger Al content BN added steel with higher Ti content cutting tool, the influence of BN addition on the tool wear reduction was more remarkable.[議事録

The influence of cutting edge sharpness on surface finish in facing with round nosed cutting tools

The range of and particularly the minimumsurface roughnesses achievable mainly with cemented carbide but also with single crystal diamond round nosed turning and facing inserts has been experimentally studied, machining aluminium and steel on engineering and precision lathes. Characteristic variations of machined surface profile with feed rate as well as insert edge sharpness and roughness measurements are reported. For aluminium faced by carbide inserts on precision lathes, insert edge radius (re) rather than feed marks determined Rz at low feeds, with Rz 0.02re. For steel work material, its properties rather than the insert edge radius became the Rz determining factor

REARRANGEMENT OF c-myc GENE

The c-myc oncogene was found to be rearranged in a human cell line of giant cell carcinoma of the lung (C-Lu65) and in a human primary giant cell carcinoma of the lung (LuC38C). The rearrangements in C-Lu65 and LuC38C were in regions about 7.5kb and 6kb, respectively, upstream from the transcription initiation site. No rearrangement of the c-myc gene was observed in a non-cancerous portion (LuC38N) of the lung of the patient who carried LuC38C. These results suggest that rearrangement of the c-myc gene may play some role in tumorigenesis of giant cell carcinoma of the lung

Surface finishes from turning and facing with round nosed tools

The range of surface roughnesses, and particularly the minimum roughnesses, achievable mainly with cemented carbide but also with single crystal diamond round nosed turning and facing inserts, has been experimentally studied, machining aluminium on engineering and precision lathes. Insert edge sharpness and roughness measurements and characteristic variations with feed rate of machined surface profile are presented. When machine tool limits are avoided, Rz values down to 0.02 times the insert edge radii have been obtained