Studies on induction hardening of powder-metallurgy-processed Fe-Cr/Mo alloys

Induction hardening of dense Fe-Cr/Mo alloys processed via the powder-metallurgy route was studied. The Fe-3Cr-0.5Mo, Fe-1.5Cr-0.2Mo, and Fe-0.85Mo pre-alloyed powders were mixed with 0.4wt%, 0.6wt%, and 0.8wt% C and compacted at 500, 600, and 700 MPa, respectively. The compacts were sintered at 1473 K for 1 h and then cooled at 6 K/min. Ferrite with pearlite was mostly observed in the sintered alloys with 0.4wt% C, whereas a carbide network was also present in the alloys with 0.8wt% C. Graphite at prior particle boundaries led to deterioration of the mechanical properties of alloys with 0.8wt% C, whereas no significant induction hardening was achieved in alloys with 0.4wt% C. Among the investigated samples, alloys with 0.6wt% C exhibited the highest strength and ductility and were found to be suitable for induction hardening. The hardening was carried out at a frequency of 2.0 kHz for 2-3 s. A case depth of 2.5 mm was achieved while maintaining the bulk (interior) hardness of approximately HV 230. A martensitic structure was observed on the outer periphery of the samples. The hardness varied from HV 600 to HV 375 from the sample surface to the interior of the case hardened region. The best combination of properties and hardening depth was achieved in case of the Fe-1.5Cr-0.2Mo alloy with 0.6wt% C.     

Network modeling links breast cancer susceptibility and centrosome dysfunction

Many cancer-associated genes remain to be identified to clarify the underlying molecular mechanisms of cancer susceptibility and progression. Better understanding is also required of how mutations in cancer genes affect their products in the context of complex cellular networks. Here we have used a network modeling strategy to identify genes potentially associated with higher risk of breast cancer. Starting with four known genes encoding tumor suppressors of breast cancer, we combined gene expression profiling with functional genomic and proteomic (or 'omic') data from various species to generate a network containing 118 genes linked by 866 potential functional associations. This network shows higher connectivity than expected by chance, suggesting that its components function in biologically related pathways. One of the components of the network is HMMR, encoding a centrosome subunit, for which we demonstrate previously unknown functional associations with the breast cancer-associated gene BRCA1. Two case-control studies of incident breast cancer indicate that the HMMR locus is associated with higher risk of breast cancer in humans. Our network modeling strategy should be useful for the discovery of additional cancer-associated genes.     

The chromosomes ofPasseromyia heterochaeta Villeneuve (Muscidae: Diptera)

Summary The 2 n=10 complement ofPasseromyia heterochaeta Villeneuve consists of 4 pairs of metacentric chromosomes and 1 pair of dots. The evolutionary implications of 2 n=10 in the tribe Phaoniini (Fam. Muscidae) are discussed.Acknowledgments. Thank are due to Dr Adrian C. Pont of British Museum (Natural Histoty), London for identifying our speciens through the courtesy of Dr Rokuro Kano, Dean Faculty of Medicine, Tokyo Medical and Dental University Tokyo, Japan. We also thank Dr U.S. Srivastava, Professor and Head, Dept. of Zoology, Univ. of Allahabad for providing the necessary laboratory faclities.     

Asynchronous puffing in the foot pad chromosomes ofParasarcophaga

Summary The foot pad polytene chromosome IIIL ofParasarcophaga ruficornis andP. misera shows a heterozygous puff in the region 7B-C. InP. ruficornis the heterozygosity is manifested as a difference in the timing of puffing between the 2 homologues. The outer and inner dorsal cells of the same foot pad also reveal asynchrony in puffing at this locus.Acknowledgments. Thanks are due to Prof. U.S. Srivastava, Head, Dept. of Zoology, University of Allahabad for providing the laboratory facilities.     

Chloroplast DNA from higher plants replicates by both the Cairns and the rolling circle mechanism.

The chloroplast DNA (ctDNA) from pea and corn plants contains both Cairns type and rolling circle replicative intermediates. Denaturation mapping studies with pea ctDNA molecules have shown that the rolling circles initiate replication at or near the site where the Cairns replicative intermediates terminate replication. These results suggest that the rolling circles are initiated by a Cairns round of replication. A model for the replication of the chloroplast DNA is based on these results.     

Similarities between metallothionein and low molecular weight testicular cadmium-binding protein

The incorporation of 35S-cysteine and 3H-glutamic acid was studied in mouse hepatic and renal metallothionein and in testicular cadmium-binding protein of similar molecular weight. Preferential incorporation of 35S-cysteine over 3H-glutamic acid was observed not only in hepatic and renal metallothionein, but also in testicular cadmium-binding protein. When the antigenic reactivity of these proteins was compared, all three proteins reacted with the metallothionein antibody. These similarities suggest that the low molecular weight testicular cadmium-binding protein is apparently metallothionein.     

Inhibition of growth of the seedlings ofPhaseolus radiatus Linn. by N-benzyl orthofluorophenoxy acetamide — A new growth retardant

Zusammenfassung Die Wirkung des N-benzyl-Derivates von Orthofluorophenoxyacetamid als Wachstumshemmer wird beschrieben.