X-ray properties of the microquasar GRS 1915+105 during a variability class transition

We present a detailed X-ray study of the microquasar GRS 1915+105 during a variability class transition observed in 2000 June with the PPCs of the Indian X-ray Astronomy Experiment. We supplement this observation with data from the RXTE archives. The source made a transition from a steady low-hard state to a regular oscillatory behaviour in the light curve known as bursts or class `rho' (Belloni et al. 2000) between 2000 May 11 and 17 and reverted back to the low-hard state on 2000 June 27. A gradual change in the burst recurrence time from about 75 s to about 40 s was observed which then increased to about 120 s during the ~ 40 days of class `rho'. The regular bursts disappeared from the X-ray light curves and the class transition was observed to occur within 1.5 hours on 2000 June 27 with the PPCs. A correlation is found between the observed QPO frequency at 5-8 Hz in the quiescent phase and the average X-ray intensity of the source during the class `rho'. We notice a strong similarity between the properties of the source during the class `rho' and those during the oscillatory phase of the observations of class `alpha'. From the timing and spectral analysis, it is found that the observed properties of the source over tens of days during the class `rho' are identical to those over a time scale of a few hundreds of seconds in the class `alpha'. Examining the light curves from the beginning of the RXTE/PCA and RXTE/ASM observations, it is found that the change of state from radio-quiet low-hard state to high state occurs through the X-ray classes `rho' and `alpha' which appear together during the state transition. It is further inferred that the source switches from low-hard state to the class `rho' through the intermediate class `alpha'.Comment: 10 pages with 9 figures, LaTex. To be appeared in MNRA

Differences in peripheral noradrenergic function among actively drinking and abstinent alcohol-dependent individuals.

We examined whether excessive alcohol consumption was related to changes in plasma levels of noradrenaline (NA) and whether these changes recover following abstinence. We also explored whether there were differences in NA levels between Type I and Type II alcoholics and controls during active drinking and abstinence. Plasma concentrations of NA were determined in (1) 27 Caucasian men with alcohol dependence who were regularly drinking (active drinkers) within 24 hours of hospitalization, (2) 29 Caucasian alcohol-dependent men who were in remission (abstinent for a minimum of three months), and (3) 28 race- and gender-matched healthy controls. NA concentrations were significantly higher in actively drinking alcohol-dependent subjects compared to those in remission and controls. While Type I and Type II alcoholic individuals differed across clinical measures, NA levels were similar in the two subtypes. Both subtypes showed an elevation in NA levels during active drinking compared to controls, but NA levels did not differ between the two subtypes and controls during remission. The findings indicate that chronic exposure to alcohol may lead to disturbances in NA activity that may manifest in early abstinence. However, the changes in NA activity appears to normalize after a longer period of abstinence. Alterations in NA activity do not seem to be specific for Type I or Type II subtypes of alcoholism

Evaluation of a "flipped" classroom model within a pharmacy professional practice class: a comparison across three consecutive cohorts

Background: The “flipped” classroom model promotes student responsibility for learning and increased one-on-one interaction with the instructor (Bergmann & Sams, 2012) allowing classroom time to be maximised for more complex activities. This model was first implemented during the Professional Practice (dispensing) classes of the M.Pharm programme at the University of Nottingham in September 2014. Aims: To investigate student performance across three consecutive cohorts at the Malaysia campus, one before and two after the implementation of the “flipped” classroom model. Method: Students’ performance for one particular practical each during the 2nd and 1styear of the programme was retrospectively analysed. Average exercises completed per student, percentage who completed a complex exercise requiring role-play, and percentage making a particular serious error were monitored. Data were analysed using descriptive statistics. Ethical approval was secured from the Science & Engineering Research Ethics Committee of the university. Results: Average exercises completed during the 2ndyear practical significantly ( p<0.01) increased from 5.44 (±1.31) prior to implementation to 6.47 (±1.95) and 6.23 (±2.15) during the 1st and 2nd year of implementation respectively. Percentage who completed complex exercises increased from 67.0% to 79.6% and 77.7% respectively. Average exercises completed during the 1st year practical significantly decreased (p<0.01) from 7.57 (±0.79) prior to implementation to 5.86 (±1.74) and 6.62 (±1.63) during the 1st and 2nd year of implementation respectively. Percentage of students making a serious error dropped from 39.3% to 19.7% and 28.4% respectively. Conclusion: The increase in complex exercises completed suggests this model allows students to cover more material at greater depth. The fewer serious errors made suggests that prior preparation allows students to progress faster. The reduction in total output among 1st year students, however, could be because when simpler exercises are involved, students’ ability to manage time effectively in class is adversely affected with prior knowledge of the class exercises. Further studies to assess students’ performance in later years of the programme will be valuable to fully appreciate the outcome of this model

Preparation and evaluation of chitosan based thermoreversible gels for intraperitoneal delivery of 5-fluorouracil (5-FU)

Sterile thermoreversibly gelling systems based on chitosan-glycerol phosphate were developed for intraperitoneal delivery of the antineoplastic agent 5-FU. The formulation was evaluated for gelling characteristics and in vitro drug release. Drug free gels were evaluated for in vitro cytotoxicity in L-929 mouse fibroblast cells. Drug loaded gels were subjected to acute toxicity studies in Swiss albino mice via intraperitoneal route and efficacy studies via intratumoral injections in subcutaneous colon carcinoma bearing BALB/c mice. The formulations gelled reversibly in 8 min at 37 oC and provided prolonged release of the drug. Drug free systems showed dose dependent cytotoxicity in fibroblast cells, while in vivo studies revealed a 2.8 fold increase in LD50 of 5-FU administered intraperitonealy as the developed system. Tumor volume measurements showed comparable efficacy of 5-FU administered as gel and commercial injection with greatly improved safety profile of the former as adjudged from mortality and body weight measurements