Validity testing of classroom community scale in virtual environment learning: A cross sectional study.

BACKGROUND: Fostering a Sense of Classroom Community is considered to be associated with the reduction of student's dropout rate in an online environment. Many scales have been developed to measure sense of community in online and traditional learning, and Rovai's Classroom Community Scale has been widely used. This study was designed to examine the psychometric properties and the theoretical structure of the Classroom Community Scale. MATERIALS AND METHODS: A total of 215 postgraduate virtual students responded to the Classroom Community Scale. A measurement model was evaluated using confirmatory factor analysis to determine the adequacy of goodness-of-fit to sample data. RESULTS: The confirmatory factor analysis provided valid data that the Classroom Community Scale with a two-factor structure is a valid scale with adequate model fit. Connectedness and learning subscales were also valid and reliable. Overall, the results supported the high reliability, face and content validity of all items of the scale. CONCLUSIONS: The 20 item Classroom Community Scale provides a valid and reliable scale to measure sense of community among postgraduate medical education students.

Fractionation and characterization of Cerastes cerastes cerastes snake venom and the antitumor action of its lethal and non-lethal fractions.

In the present study fractionation of the Cerastes cerastes cerastes snake venom by gel filtration on Sephadex G-75 gave 14 protein fractions. Phospholipase PLA2 activity is not uniformly correlated with the lethality to mice in regard to all venom fractions. F11 which is the richest in PLA2 activity is less toxic than F3, which contains a small amount of PLA2, and F12 is the lowest in lethality and PLA2 activity. Treatment of Ehrlich ascites-bearing mice with two i.p. injections of the most lethal fraction (F3) or a non-lethal fraction (F4) resulted in a significant antitumor activity demonstrated by an increase in the mean survival time of the animals (22.5 and 27.9 days) and in the tumor inhibition ratio of tumor growth (T/C% 139 and 172, respectively), compared to tumor-bearing controls. The cytotoxic activity of F3 and F4 against Ehrlich ascites carcinoma cells might be due to the presence of a cytotoxin rather than to the direct cytolytic effect of the PLA2 because the non-lethal F4 is free from PLA2. Treatment of Swiss albino mice with two i.p. injections of F3 or F4 at the adopted dose levels produced no detrimental side effects demonstrated by the insignificant changes in the tested serum and liver parameters. Treatment of the tumor-bearing mice with the same venom fractions significantly modulated all of the studied biochemical parameters in the serum and liver tissues, compared to normal controls.

[Emergencies in oncologic surgery of the large intestine]. / Le urgenze nella chirurgia oncologica del grosso intestino.

The authors analyse of the large intestine at their Institute over the past 20 years. Four hundred and fifty-two cases out of 842 were performed during the period 1970-1979 and 300 during the subsequent decade. 21% (95 cases) were emergencies during the first decade and 16% (62 cases) during the second. From this study it emerges that patients operated with primary resection during the first decade 1970-1979 had a better survival rate than those operated in various stages. This was particularly true of cases of occlusion, whereas in cases of perforation the percentage remained practically unchanged. The approach adopted for this type of pathology changed during the next decade and it was decided to opt for primary resective surgery. A comparison between emergency surgery performed in a single session and operations performed in a number of stages revealed that both survival and morbidity were improved in primary resective surgery, 20% and 10% respectively, whereas mortality was higher (15%).