Nitrocarburizing of low-carbon unalloyed steel

Low-carbon unalloyed steel has been investigated after nitriding accomplished by either the salt-bath method (Tenifer) or the gas method (Nitroc). The resulting changes in the mechanical properties are reported in this paper, while changes in positron annihilation parameters are reported in Part 2. The mechanical properties show that the increase in both the lower yield stress and the ultimate stress is influenced greatly by the cooling rate after nitriding. A rapid cooling rate resulted in an increase of ～200 MPa while an increase of only 55 Mpa was observed for a slow cooling rate. These increases proved independent of prior straining in the range 0 to 20%, showing that the nitrogen uptake is not significantly influenced by internal defects. Annealing of rapidly cooled nitrided specimens resulted in a maximum of both the lower yield stress and the ultimate yield stress around 100° C. A transition from brittle to ductile fracture around this temperature was also observed. A large recovery of elongation to fracture was obtained after annealing at 140° C, which was not accompanied by any significant decrease in the lower yield stress. Dilatometer measurements indicated two precipitation stages, one around room temperature and another around 100° C.     

Comparison of two multisheet transmission windows formillimeter-wave radiometers

The design and performance of a triple-sheet Mylar window and a Teflon-and-foam window are studied theoretically and experimentally to determine which window produces the smaller brightness temperature variations and, therefore, leads to better accuracy of radiometers operating at frequencies of 20-90 GHz. Theoretical brightness temperatures due to emission and reflection by the windows are calculated and compared; experimental measurements obtained by using the clear atmosphere as a radiation source are also compared. Both theory and experiment indicate that the Teflon-and-foam window produces smaller brightness temperature variations at these operating frequencies. Effects of the windows on integrated water vapor and liquid measurements are also examined; errors are significant for the triple-sheet Mylar window but are negligible for the Teflon-and-foam window. It is observed that use of the Teflon-and-foam design results in acceptably small errors in radiometric measurements of water vapor and cloud liquid     

Traumatic rupture of duodenal diverticulum. Report of a case and literature review

Duodenal diverticulum is a common anatomic abnormality. Its inflammatory perforation is a rare complication, with less than 100 cases reported in the available literature. Traumatic perforation is exceedingly rare (only 3 cases reported). In this report one more case of traumatic perforation is presented, and the literature is reviewed focusing on the pathogenic, diagnostic and therapeutic aspects of this severe disease.     

Production of type II collagen specific monoclonal antibodies

Immunoassays are used for the specific measurement of type II collagen, a major cartilage protein, which is lost in osteoarthritic joints. Poor immunogenicity and species dependent immune response to type II collagen make it difficult to obtain specific antibodies required for immunoassay development. In addition, type II collagen antibodies exhibit reactivity to structurally dissimilar antigens such as actin, myoglobin, thyroglobulin and ssDNA, complicating the isolation of specific antibodies. It is therefore necessary to characterize the antibody reactivity against both noncollagenous antigens and different collagen types. In this study, immune response to type II collagen was improved by conjugation to carrier proteins, KLH and BSA. Hybridomas were generated by fusions of lymphocytes derived from lymph nodes or spleens with X63-653-Ag8 myeloma cells. Compared to spleens, the utilization of lymph nodes as a source of lymphocytes resulted in a 23% higher number of hybridomas secreting type II collagen antibodies. Hybridomas secreting polyreactive antibodies were identified based on their reactivity to thyroglobulin and eliminated. Extensive testing of the remaining monoclonal antibodies with other structurally dissimilar antigens and various types of collagen for reactivity, allowed us to isolate specific monoclonal antibodies to type II collagen. We emphasize the importance of characterization of the reactivity of type II collagen monoclonal antibodies before employing them for immunoassays.     

A comparison of cognitive and interpersonal-process group therapies in the treatment of depression among college students.

We compared cognitive (CT) and interpersonal-process (IP) group therapies in the treatment of moderate, unipolar depression in college counseling-center clients. Subjects who sought services early in the semester were randomly assigned to CT or IP groups and compared with a waiting-list group composed of subjects who requested services just prior to the Christmas recess. Multivariate analyses revealed no significant differences between treatment and waiting-list conditions. Because the control was confounded by the Christmas holiday, we compared the CT and IP groups directly. Both treatments led to significant reductions in depression and depressed thinking and to increments in self-esteem at midtreatment, posttreatment, and follow-up assessments but did not differ from each other at any other time. There was no evidence of differential effectiveness or mechanisms of therapeutic change as a function of type of treatment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)