The influence of carbon impurities on the formation of loops in tungsten irradiated with self-ions

The microstructure changes taking place in W under irradiation are governed by many factors, amongst which C impurities and their interactions with self-interstitial atoms (SIA). In this work, we specifically study this effect by conducting a dedicated 2-MeV self-ions irradiation experiment, at room temperature. Samples were irradiated up to 0.02, 0.15 and 1.2 dpa. Transmission electron microscopy (TEM) expectedly revealed a large density of SIA loops at all these doses. Surprisingly, however, the loop number density increased in a non-monotonous manner with the received dose. Performing chemical analysis with secondary ion spectroscopy measurements (SIMS), we find that our samples were likely contaminated by C injection during the irradiation. Employing an object kinetic Monte Carlo (OKMC) model for microstructure evolution, we demonstrate that the C injection is the likely factor explaining the evolution of loops number density. Our findings highlight the importance of the well-known issue of C injection during ion irradiation experiments, and demonstrate how OKMC models can help to rationalize this effect.Peer reviewe

Antitumorigenic effect of proteasome inhibitors on insulinoma cells.

Malignant insulinoma is a critical cancer form with a poor prognosis. Because cure by surgery is infrequent, effective chemotherapy is in demand. Induction of cell death in tumor cells by proteasome inhibitors is emerging as a potential strategy in cancer therapy. Here we investigated whether inhibition of the proteasome has an antitumorigenic potential in insulinoma cells. Exposure of mouse betaTC3 insulinoma cells to the proteasome inhibitor N-Acetyl-Leu-Leu-Nle-CHO (ALLN) reduced cell viability, activated caspase-3, induced apoptosis, and suppressed insulin release. Treatment with ALLN also resulted in phosphorylation of c-jun N-terminal kinase (JNK) and an increase in in vitro phosphorylation of c-jun. In insulinoma cells with impaired JNK signaling, ALLN-induced apoptosis was significantly suppressed. Another proteasome inhibitor, lactacystin, also stimulated JNK activation, caused activation of caspase-3, suppressed cell viability, and induced apoptosis in betaTC3 and rat INS-1E cells. Both ALLN and lactacystin caused a marked decrease in the cellular amount of the JNK scaffold protein JNK-interacting protein 1/islet-brain-1. In primary pancreatic rat islet cells, proteasome inhibition reduced insulin secretion but had no impact on cell viability and even partially protected against the toxic effect of proinflammatory cytokines. Our findings demonstrate that proteasome inhibitors possess antitumorigenic and antiinsulinogenic effects on insulinoma cells

Young women's continued use of oral contraceptives over other hormonal methods: findings from a qualitative study

Background Long-acting reversible contraceptives (LARC) have become more commonly promoted in the UK, but most young women still rely on the contraceptive pill. Here, we describe young women's accounts of hormonal contraceptive use to explore why this might be the case. Methods In-depth interviews with twenty 20-year-old women from eastern Scotland in the UK. Results All but one woman reported use of the pill. It was the method they expected to use, sought out, and received. Belief in the pill's efficacy was maintained even when knowledge or experience of failure suggested otherwise. Only four women reported using alternative hormonal methods and only did so after experiencing unmanageable problems with the pill (side effects or forgetting to take it). All then discontinued use because of weight gain or dislike of menstrual suppression. Conclusions Attempts to promote LARC must address these issues. Pill use can be unproblematic if managed well, and should continue to be promoted as an appropriate contraceptive for young women