Thermally induced mixing of water dominated interstellar ices

Despite considerable attention in the literature being given to the desorption behaviour of smaller volatiles, the thermal properties of complex organics, such as ethanol (C2H5OH), which are predicted to be formed within interstellar ices, have yet to be characterized. With this in mind, reflection absorption infrared spectroscopy (RAIRS) and temperature programmed desorption (TPD) have been used to probe the adsorption and desorption of C2H5OH deposited on top of water (H2O) films of various thicknesses grown on highly oriented pyrolytic graphite (HOPG) at 98 K. Unlike many other molecules detected within interstellar ices, C2H5OH has a comparable sublimation temperature to H2O and therefore gives rise to a complicated desorption pro. le. RAIRS and TPD show that C2H5OH is incorporated into the underlying ASW film during heating, due to a morphology change in both the C2H5OH and H2O ices. Desorption peaks assigned to C2H5OH co-desorption with amorphous, crystalline (CI) and hexagonal H2O-ice phases, in addition to C2H5OH multilayer desorption are observed in the TPD. When C2H5OH is deposited beneath ASW films, or is co-deposited as a mixture with H2O, complete co-desorption is observed, providing further evidence of thermally induced mixing between the ices. C2H5OH is also shown to modify the desorption of H2O at the ASW-CI phase transition. This behaviour has not been previously reported for more commonly studied volatiles found within astrophysical ices. These results are consistent with astronomical observations, which suggest that gas-phase C2H5OH is localized in hotter regions of the ISM, such as hot cores

The adsorption and desorption of ethanol ices from a model grain surface

Reflection absorption infrared spectroscopy (RAIRS) and temperature programed desorption (TPD) have been used to probe the adsorption and desorption of ethanol on highly ordered pyrolytic graphite (HOPG) at 98 K. RAIR spectra for ethanol show that it forms physisorbed multilayers on the surface at 98 K. Annealing multilayer ethanol ices (exposures > 50 L) beyond 120 K gives rise to a change in morphology before crystallization within the ice occurs. TPD shows that ethanol adsorbs and desorbs molecularly on the HOPG surface and shows four different species in desorption. At low coverage, desorption of monolayer ethanol is observed and is described by first-order kinetics. With increasing coverage, a second TPD peak is observed at a lower temperature, which is assigned to an ethanol bilayer. When the coverage is further increased, a second multilayer, less strongly bound to the underlying ethanol ice film, is observed. This peak dominates the TPD spectra with increasing coverage and is characterized by fractional-order kinetics and a desorption energy of 56.3 +/- 1.7 kJ mol(-1). At exposures exceeding 50 L, formation of crystalline ethanol is also observed as a high temperature shoulder on the TPD spectrum at 160 K. (c) 2008 American Institute of Physics

Size-Dependent Expression of the Mitotic Activator Cdc25 as a Mechanism of Size Control in Fission Yeast [preprint]

Proper cell size is essential for cellular function (Hall et al., 2004). Nonetheless, despite more than 100 years of work on the subject, the mechanisms that maintain cell size homeostasis are largely mysterious (Marshall et al., 2012). Cells in growing populations maintain cell size within a narrow range by coordinating growth and division. Bacterial and eukaryotic cells both demonstrate homeostatic size control, which maintains population-level variation in cell size within a certain range, and returns the population average to that range if it is perturbed (Marshall et al., 2012; Turner et al., 2012; Amodeo and Skotheim, 2015). Recent work has proposed two different strategies for size control: budding yeast has been proposed to use an inhibitor-dilution strategy to regulate size at the G1/S transition (Schmoller et al., 2015), while bacteria appear to use an adder strategy, in which a fixed amount of growth each generation causes cell size to converge on a stable average, a mechanism also suggested for budding yeast (Campos et al., 2014; Jun and Taheri-Araghi, 2015; Taheri-Araghi et al., 2015; Tanouchi et al., 2015; Soifer et al., 2016). Here we present evidence that cell size in the fission yeast Schizosaccharomyces pombe is regulated by a third strategy: the size dependent expression of the mitotic activator Cdc25. The cdc25 transcript levels are regulated such that smaller cells express less Cdc25 and larger cells express more Cdc25, creating an increasing concentration of Cdc25 as cell grow and providing a mechanism for cell to trigger cell division when they reach a threshold concentration of Cdc25. Since regulation of mitotic entry by Cdc25 is well conserved, this mechanism may provide a wide spread solution to the problem of size control in eukaryotes

Surface science investigations of the role of CO2 in astrophysical ices

We have recorded reflection–absorption infrared spectroscopy (RAIRS) and temperature-programmed desorption (TPD) data for a range of CO2-bearing model astrophysical ices adsorbed on a graphitic dust grain analogue surface. Data have been recorded for pure CO2, for CO2 adsorbed on top of amorphous solid water, for mixed CO2:H2O ices and for CO2 adsorbed on top of a mixed CH3OH:H2O ice. For the TPD data, kinetic parameters for desorption have been determined, and the trapping behaviour of the CO2 in the H2O (CH3OH) ice has been determined. Data of these types are important as they can be used to model desorption in a range of astrophysical environments. RAIR spectra have also shown the interaction of the CO2 with H2O and CH3OH and can be used to compare with astronomical observations, allowing the accurate assignment of spectra

A feasibility trial of Power Up: A smartphone app to support patient activation and shared decision making for mental health in young people

Background: Digital tools have the potential to support patient activation and shared decision making in the face of increasing levels of mental health problems in young people. There is a need for feasibility trials of digital interventions to determine the usage and acceptability of interventions. In addition, there is a need to determine the ability to recruit and retain research participants to plan rigorous effectiveness trials and therefore, develop evidence-based recommendations for practice. Objective: To determine the feasibility of undertaking a cluster randomized control trial to test the effectiveness of a smartphone app, Power Up, co-designed with young people to support patient activation and shared decision making for mental health. Methods: Overall, 270 young people were screened for participation and 53% (N = 142) were recruited and completed baseline measures across eight specialist child mental health services (n = 62, mean (SD) age = 14.66 (1.99) years, 52% female) and two mainstream secondary schools (n = 80; mean (SD) age = 16.88 (0.68) years, 46% female). Young people received Power Up in addition to management as usual or received management as usual only. Post-trial interviews were conducted with 11 young people from the intervention arms (specialist services n = 6; schools n = 5). Results: Usage data showed that there were an estimated 50 (out of 64) users of Power Up in the intervention arms. Findings from the interviews indicated that young people found Power Up to be acceptable. Young people reported: 1) their motivation for use of Power Up, 2) the impact of use, and 3) barriers to use. Out of the 142 recruited participants, 45% (64/142) completed follow up measures, and the approaches to increase retention agreed by the steering group are discussed. Conclusions: The findings of the present research indicate that the app is acceptable and it is feasible to examine the effectiveness of Power Up in a prospective cluster randomized control trial. Clinical Trial: ISRCTN: ISRCTN77194423, ClinicalTrials.gov NCT0255279

Prevalence and incidence of hypoglycaemia in 532,542 people with Type 2 diabetes on oral therapies and insulin: a systematic review and meta-analysis of population based studies

Objective: To collate and evaluate the current literature reporting the prevalence and incidence of hypoglycaemia in population based studies of type 2 diabetes. Research design and methods: Medline, Embase and Cochrane were searched up to February 2014 to identify population based studies reporting the proportion of people with type 2 diabetes experiencing hypoglycaemia or rate of events experienced. Two reviewers independently screened studies for eligibility and extracted data for included studies. Random effects meta-analyses were carried out to calculate the prevalence and incidence of hypoglycaemia. Results: 46 studies (n=532,542) met the inclusion criteria. Prevalence of hypoglycaemia was 45% (95%CI 0.34,0.57) for mild/moderate and 6% (95%CI, 0.05,0.07) for severe. Incidence of hypoglycaemic episodes per person-year for mild/moderate and for severe was 19 (95%CI 0.00, 51.08) and 0.80 (95%CI 0.00,2.15), respectively. Hypoglycaemia was prevalent amongst those on insulin; for mild/moderate episodes the prevalence was 50% and incidence 23 events per person-year, and for severe episodes the prevalence was 21% and incidence 1 event per person-year. For treatment regimes that included a sulphonylurea, mild/moderate prevalence was 30% and incidence 2 events per person-year, and severe prevalence was 5% and incidence 0.01 events per person-year. A similar prevalence of 5% was found for treatment regimes that did not include sulphonylureas. Conclusions: Current evidence shows hypoglycaemia is considerably prevalent amongst people with type 2 diabetes, particularly for those on insulin, yet still fairly common for other treatment regimens. This highlights the subsequent need for educational interventions and individualisation of therapies to reduce the risk of hypoglycaemia

Forest plot showing the proportion of people experiencing severe hypoglycaemia in each study and the overall pooled estimate.

<p>Boxes and horizontal lines represent proportion if people experiencing severe hypoglycaemia and 95% CI for each study. Size of box is proportional to weight of that study result. Diamonds represent the 95% CI for pooled estimates of effect and are centred on pooled hypoglycaemia incidence.</p

Meta-regression results showing the effect of study-level variables on the proportion of people experiencing each severity of hypoglycaemia.

<p>Abbreviations: CI, Confidence Interval; HbA1c, glycated haemoglobin.</p><p>Meta-regression results showing the effect of study-level variables on the proportion of people experiencing each severity of hypoglycaemia.</p