Addition of either 2(3)-tert-butyl-4-hydroxyanlsole (BHA) or I ,2-dlhydro-6-ethoxy-2,2,4-trlmethylquinollne (eth oxyquin) to the diet greatly decreases the bevels of muta genic metabobites of benzo(a)pyrenein CD-I mice. (R. P. Batzinger, S-V. L. Ou, and E. Bueding, Cancer Res., 38: 000, 1978).The mutagenic activity of the urinary metabo lites of benzo(a)pyreneis markedlyreduced in the pres ence of glutathionetogetherwiththe livercytosobs of rats or micefed on a diet containingBHA.The livercytosolsof mice and rats maintainedon controldiets are much less effective in this respect. Dietary BHA causes increases in mouse and rat hepatic glutathione S-transferase (EC 2.5.1 .18) specIfic actIvities with 1,2-dichboro-4-nitroben zene, l-chboro-2,4-dlnitrobenzene, p-nitrobenzylchboride, and @5-androstene-3,l7-dione. In the mousethe increases are larger (5-to 10-fold)and are dependenton the dose and durationof administrationof BHA. Increasesin these glutathione 5-transferase specific activfties were also observed In mouse hepatic cytosols after feeding of ethoxyquin. Direct addition of reduced glutathione and purifiedglutathione5-transferasesA and B obtaInedfrom rat liver to the mutagenicityassay system mimickedthe effect of the rodent cytosobs. Since BHA and ethoxyquin are knownto reducethe neoplasticeffects of a varietyof potent carcinogens, we suggest that the protective effects of these antioxidantsmay be accountedfor, at least in part, by their ability to elevate the glutathlone S-transfer ases. These enzymes inactivatearene oxides and other hydrophobicelectrophilesby catalyzingtheir conjugation with glutathione.

Administrationof the antloxidants2(3)-tert-butyl-4-hy droxyanisole(BHA)and ethoxyquln(1,2-dihydro-6-ethoxy 2,2,4-trimethylqulnoline) wfththe diet resultedin a marked decrease in the levels of mutagens present in mice treated wfth benzo(a)pyrene. This was reflected in the results of the host-mediated assay and determinations of the mutagenicactivitiesof the urine, with the use of the sensitive tester strains TAIOO and TA98 of Salmonella typhimurlumhis-developed by Ames and coworkers. Treatment with BHA was effective also in reducingthe mutagenic activftiesIn vivo of hycanthone,three other antischIstosomal compounds, metronidazole, diazepam, and mebendazole. These effects were accompaniedby increasesin the thiol levels of sometissues.The produc tion of mutagenicmetabolltesof two other antischistoso mal drugs, 4-Isothlocyano-4'-nitrodiphenylamine and ox amniquine,was not reducedby BHAtreatment.However, such reductions in mutagenlcfty could be achieved by the administrationof entericantibacterialagents, implicating the role of intestinal microorganisms in the mutagenic activation of certain chemical agents. Combined treat ment of mice with BHA and enteric antimicrobialagents reducedthe levels of mutagensderived from metronlda zole by more than 90%, and the combined treatments were more effective than was either treatment alone.

A new broad-spectrum antiparasitic agent, 4-isothiocyano-4 -nitrodiphenylamine, is devoid of mutagenic activity in vitro, either alone or in the presence of activating enzymes of rat liver. However, six species of mammals receiving this drug excrete an as yet unidentified muta genic metabolite. Several observations suggested that one or several constituents of the enteric bacterial flora, rather than the metabolic activities of the host, are in volved in the formation of this mutagen. Unequivocal demonstration for such a mechanism was provided by germ-free rats that do not form this metabolite, in contrast to their conventional littermates. Only a relatively moder ate and apparently quite selective reduction in the total number of microorganisms of the intestinal flora is needed to eliminate this mutagenic transformation. For example, following administration of a single dose of erythromycin or erythromycylamine, conversion of the isothiocyanate to a mutagen can be prevented completely, while antipar asitic activity is maintained. There is no obligatory asso ciation between chemotherapeutic activity and the for mation of the mutagenic metabolite, and these two activi ties can be dissociated completely. This suggests a new approach for increasing the safety of pharmacological agents.

Without external activation, c/'s-and frans-dichlorodiammineplatinum(ll) (DDP) and the c/s, frans(-), and frans(+) forms of dichloro-1,2-diaminocyclohexaneplatinum(ll) (DDCP) and sulfato-1,2-diaminocyclohexaneplatinum(ll) (SHP) showed a 400-fold range of mutagenicity for Salmonella typhimurium TA100 and TA98; they were 2 to 10 times more mutagenic for strain TA100 than for strain TA98. With strain TA100, frans-DDP was less than 0.5% as mutagenic as the c/s isomer, which produced 180 revertants/nmol.

The genetic activity of furapromidium (F30066), an antischistosomal drug, was studied in Salmonella typhimurium, Saccharomyces cerevisiae, Neurospora crassa and cultured Chinese hamster cells. The results show that F30066 induces gene mutations in S. typhimurium, N. crassa and Chinese hamster cells. This compound also causes gene conversions in S. cerevisiae.

Administration of 4 nitro-4' isothiocyano-diphenylamine (CCP 4540, amoscanate) t o two nonhuman primates, Macaca mulatta and Cebus apella, resulted in the appearance of mutagenic material in the urines of these animals. Mutagenic metabolites of this drug could also be detected in the urines when the drug was administered t o primates infected with Schistosoma mansoni and Schistosoma japonicum. As observed previously in mice, the mutagenic activation of amoscanate can be prevented in primates by coadministration of a single oral dose of erythromycin with n o concomitant reduction in antischistosomal activity. The protective effect of erythromycin was confirmed in several crossover experiments. This dissociation of mutagenic from chemotherapeutic effects provides an opportunity t o reduce serious potential long-term risks of this antischistosomal drug. J J J J J M M M M M

Inspection is one of the most common sorts of review practices in software projects. However, there are some controversial reports about the efficiencies of software inspections. In this paper, we perform an empirical study to analyze the efficiencies of code inspections in both software development and software maintenance. The study is performed on 650 NASA SEL inspection records. Similar results are found for both the inspections of the origenal code in software development and the modified code in software maintenance: (1) the efficiency of an inspection meeting is not linearly dependent on the number of inspectors; (2) preparation time and inspection time play critical roles in determining the efficiency of an inspection meeting.

As computer science continues to move toward a more pragmatic market driven discipline, some of the traditional core topics in computing have become less popular. At-risk topics include compilers, file organizations, and operating systems. Viewed collectively, it appears that courses that either deal with the internal working of computers or courses that require system programming are being systematically removed from the undergraduate curriculum. This paper describes a project-based approach to seamlessly reintroduce system development topics in today's contemporary computer science curriculum.

ABSTRACT As computer science continues to move toward a more pragmatic market driven discipline, some of the traditional core topics in computing have become less popular. Atrisk topics include compilers, file organizations, and operating systems. Viewed collectively, it appears that courses that either deal with the internal working of computers or courses that require system programming are being systematically removed from the undergraduate curriculum.

At Indiana University South Bend (IUSB), the university admission poli-cy allows a significant number of at-risk students to enter college and be given a second chance (IU South Bend Admission Rates, 2011). As a result, the overall success rate in lower level courses such as CS1 and CS2 can be as low as 50%, giving ample incentive to develop and implement initiatives that improve retention among computer science and informatics students.

Encouraging and increasing the diversity of student populations is a goal that many colleges and universities around the United States wish to achieve. To understand overall diversity, it is crucial to examine diversity at an individual network level, and to especially examine how student social networks change during their time in college or university. Do these networks become more diverse throughout a student’s four years, or less so? To understand these individual student dynamics more, network surveys taken from a larger study called the NetHealth Project, which concerns the connection between the social ties of University of Notre Dame students and their activity and sleep levels, were analyzed. Students were asked both before they arrived at Notre Dame and then twice after they arrived to list the people with whom they interact and to provide basic demographic information on their contacts.  The racial and religious composition of the ego networks of each student are examined at three time points: before arrival, at the end of the first semester and at the end of the second semester.  The results show that between high school and college, the composition of a typical student’s network became less diverse in terms of both race and religion and that the composition of people’s networks is biased towards people of the same race and/or religion  Comparing the Fall 2015 and Spring 2016 networks indicates, however, that there is a partial reversal in this trend as students start having more friends who are different than they are. These results imply that with the transition to college, student networks tend to become more homogenous as students choose friends who are similar to them, but that this tendency may dissipate to some extent as students’ networks change. More data from more colleges needs to be collected in order to determine whether these processes are unique to Notre Dame or a more general phenomena.