Probing the Light Pseudoscalar Window

Very light pseudoscalars can arise from the symmetry-breaking sector in many extensions of the Standard Model. If their mass is below 200 MeV, they can be long-lived and have interesting phenomenology. We discuss the experimental constraints on several models with light pseudoscalars, including one in which the pseudoscalar is naturally fermiophobic. Taking into account the stringent bounds from rare K and B decays, we find allowed parameter space in each model that may be accessible in direct production experiments. In particular, we study the photoproduction of light pseudoscalars at Jefferson Lab and conclude that a beam dump experiment could explore some of the allowed parameter space of these models.Comment: 22 pages, 4 figure

Loop quantum gravity induced modifications to particle dynamics

The construction of effective Hamiltonians arising from Loop Quantum Gravity and incorporating Planck scale corrections to the dynamics of photons and spin 1/2 particles is summarized. The imposition of strict bounds upon some parameters of the model using already existing experimental data is also reviewed.Comment: 9 pages, 0 figures, talk presented at the X Mexican School of Particles and Fields, latex, aipproc style 6x

Standardized videos in addition to the surgical curriculum in Medical Education for surgical clerkships:a cohort study

BACKGROUND: Medical students are expected to translate the theoretical knowledge gained during their study to practical knowledge during the clerkships. A surgical educational platform with standardized videos may be the solution. However, the effects of a structured online video-based platform in addition to the standard curriculum on students’ self-reported and tested surgical knowledge during the surgical clerkship must be assessed. METHODS: Fourth-year medical students (n = 178) participated in a 6-week course of theoretical and practical training followed by a 10-week in-hospital clerkship in the Erasmus University Medical Center (Erasmus MC), Rotterdam, The Netherlands and 11 affiliated general hospitals. Ninety students followed the usual surgical curriculum (control group), followed by 88 students who were given voluntary access to a video-based surgical educational platform of Incision Academy (video group). At the start (T0) and end (T1) of the clerkship, both groups filled out a surgical knowledge test and a survey regarding their self-reported surgical knowledge and their access to available study sources. Supervisors were blinded and surveyed concerning students’ performance and their acquired knowledge. We analyzed the data using paired and unpaired student t-tests and linear regression. RESULTS: At the end of the clerkship, students in the video group indicated that they had better resources at their disposal than the control group for surgical procedures (p = 0.001). Furthermore, students in the video group showed a greater increase in self-reported surgical knowledge during their clerkship (p = 0.03) and in more objectively tested surgical knowledge (p < 0.001). CONCLUSIONS: An online surgical educational platform with standardized videos is a valuable addition to the current surgical curriculum according to students and their supervisors. It improves their test scores and self-reported surgical knowledge. Students feel better prepared and more able to find the information necessary to complete the clerkship. TRIAL REGISTRATION: Registry not necessary according to ICMJE guidelines. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12909-022-03314-w

Enhanced cytostatic activity of the sesquiterpene lactone eupatoriopicrin by glutathione depletion.

Eupatoriopicrin (EUP), a sesquiterpene lactone from Eupatorium cannabinum L., possesses cytostatic activity. This was demonstrated for FIO 26 cells in vitro with the aid of a clonogenic assay and in vivo by tumour growth delay in FIO 26 and Lewis lung tumour-bearing mice. In vitro the IC50 for 1 h exposure to EUP was 1.5 microgram ml-1 (4.1 nmol ml-1). This concentration depleted about 25% of its cellular GSH concentration. Pretreatment of FIO 26 cells with BSO, resulting in greater than 99%. GSH depletion, enhanced the cytotoxic effect of EUP. The dose-enhancement factor at the level of 10% cell survival was 2.3. Growth inhibition of the Lewis lung carcinoma and the FIO 26 fibrosarcoma, solidly growing in C57Bl mice, was found after i.v. injection of 20 or 40 mg kg-1 EUP, at a tumour volume of about 500 microliters. Pretreatment with BSO at a dose of 4 mmol kg-1 i.p., 6 h before EUP administration, resulted in a significantly stronger growth delay of both tumours compared with EUP only. At the time of EUP treatment, cellular GSH in the tumours was reduced by BSO treatment to about 60%. It is concluded that EUP possesses antitumour activity in vivo and that chemosensitisation of EUP may be accomplished by pretreatment with BSO, indicating that endogenous GSH protects against the cytostatic action of EUP