Microyielding in alpha titanium

The microflow parameters of two grades of polycrystalline alpha titanium have been determined from compression tests at temperatures in the range 77 to 335 K. Specimens were tested in either annealed or prestrained conditions, and the elastic limit, microyield stress, activation volume and activation energy were determined. The data indicate that dislocations can move at the elastic limit without strong influence from interstitial solutes, except at 77 K where some solute atoms provide a barrier to motion. As the plastic strain is increased, solute obstacles play an increasing part in determining the flow stress, and the microyield stress shows a strong dependence on solute concentration. There is conflicting evidence as to the role screw dislocations have in the microflow region.     

Therapeutic trial of aniline mustard in patients with advanced cancer. Comparison of therapeutic response with cytochemical assessment of tumor cell beta-glucuronidase activity

Seventy-eight patients with advanced cancer received an adequate therapeutic trial with aniline mustard (NSC 18429). Significant anticancer activity with clinical benefit was demonstrated in five patients with cancer of the prostate and one patient with renal cancer. beta-glucuronidase levels in aspirate and imprint preparations of tumor cells were assessed by a timed cytochemical technique. A partial correlation appeared to exist between very intense glucuronidase staining and tumor regression in prostate and kidney lesions; however, these high levels were observed only rarely. Sequential observations in two patients demonstrated loss of enzymatic activity concomitant with development of clinical relapse.     

Frequency of neoplasia in systemic lupus erythematosus and rheumatoid arthritis

A patient population admitted to the hospital for either SLE or RA was surveyed for the subsequent development of neoplasms. The frequency of neoplasm in SLE patients appeared to be exaggerated, whereas the frequency of subsequent neoplasm in rheumatoid patients was unexpectedly low. A paucity of nephritis in the SLE group was noted. Further reports are encouraged so that the magnitude of the risk of malignancy developing with immunosuppressive therapy can be more precisely ascertained.     

Mobility of interstitial clusters in alpha-zirconium

Clusters of self-interstitial atoms (SIAs) formed in displacement cascades in metals irradiated with energetic particles play an important role in microstructure evolution under irradiation. They have been studied in the fcc and bcc metals by atomic-scale computer simulation, and in this article, we present the results of a similar study in a hexagonal close-packed (hcp) crystal. Static and dynamic properties of clusters of up to 30 SIAs were studied using a many-body Finnis-Sinclair type interatomic potential for Zr. The results show a qualitative similarity of some properties of clusters to those for cubic metals. In particular, all clusters larger than four SIAs exhibit fast thermally activated one-dimensional (1-D) glide, which is in a 〈11 0〉 direction in the hcp lattice. Due to the structure of the hcp lattice, this mechanism leads to two-dimensional mass transport in basal planes. Some clusters exhibit behavior peculiar to the hcp structure, for they can migrate two-dimensionally (2-D) in the basal plane. The jump frequency, activation energy, and correlation factors of clusters have been estimated, and comparisons drawn between the behavior of SIA clusters in different structures. This article is based on a presentation made in the symposium entitled “Defect Properties and Mechanical Behavior of HCP Metals and Alloys” at the TMS Annual Meeting, February 11–15, 2001, in New Orleans, Louisiana, under the auspices of the following ASM committees: Materials Science Critical Technology Sector, Structural Materials Division, Electronic, Magnetic & Photonic Materials Division, Chemistry & Physics of Materials Committee, Joint Nuclear Materials Committee, and Titanium Committee.     

Toward pervasive computing

Summary form only given. The fundamental principles that guide pervasive computing environment design evolved with distributed systems: local area networks, middleware, wide-area networks, the WWW. Over the years, ever smaller, portable computers came on the market and wireless networking technology evolved, leading to the emergence of mobile and wireless computing. Embedded computing gave us small devices, sensors and actuators, increasingly with communications capability. There are now substantial projects that demonstrate that sensor-rich environments, such as active buildings and cities, are feasible and will be deployed widely in the real world in the near future. This issue of Pervasive Computing describes several such projects.     

Trichoderma viride suppresses fumonisin B1 production by Fusarium moniliforme

Biocontrol activity against Fusarium moniliforme was analyzed for a Trichoderma viride strain isolated from root segments of corn plants grown in Piedmont Georgia. The isolate suppressed radial extension of F. moniliforme colonies during cocultivation on potato dextrose agar and fumonisin B1 (FB1) production during incubation of both fungi on corn kernels. T. viride decreased radial extension of F. moniliforme by 46% after 6 days and by 90% after 14 days. Furthermore, the colony diameter of F. moniliforme was less at 14 days than at 5 days, suggesting that F. moniliforme mycelia were undergoing lysis. FB1 production by F. moniliforme on corn kernels decreased by 85% when both organisms were inoculated the same day onto corn kernels and by 72% when inoculation of T. viride was delayed by 7 days after F. moniliforme inoculation. These results are the first to demonstrate that T. viride can suppress FB1 production by F. moniliforme, thereby functioning to control mycotoxin production. Thus, this isolate may be useful in biological control to inhibit F. moniliforme growth as a preharvest agent to prevent disease during plant development and/or as a postharvest agent during seed storage to suppress FB1 accumulation when kernels are dried inadequately.