The P2Y1 receptor is involved in the maintenance of glucose homeostasis and in insulin secretion in mice

Pancreatic β cells express several P2 receptors including P2Y1 and the modulation of insulin secretion by extracellular nucleotides has suggested that these receptors may contribute to the regulation of glucose homeostasis. To determine whether the P2Y1 receptor is involved in this process, we performed studies in P2Y1 mice. In baseline conditions, P2Y1-mice exhibited a 15% increase in glycemia and a 40% increase in insulinemia, associated with a 10% increase in body weight, pointing to a role of the P2Y1 receptor in the control of glucose metabolism. Dynamic experiments further showed that P2Y1-mice exhibited a tendency to glucose intolerance. These features were associated with a decrease in the plasma levels of free fatty acid and triglycerides. When fed a lipids and sucrose enriched diet for 15 weeks, the two genotypes no longer displayed any significant differences. To determine whether the P2Y1 receptor was directly involved in the control of insulin secretion, experiments were carried out in isolated Langerhans islets. In the presence of high concentrations of glucose, insulin secretion was significantly greater in islets from P2Y1-mice. Altogether, these results show that the P2Y1 receptor plays a physiological role in the maintenance of glucose homeostasis at least in part by regulating insulin secretion

Addressing emerging risks using carbon capture and storage as an example

The European iNTeg-Risk project is a large-scale integrated project aimed at improving the management of emerging risks related to new technologies in European industry. The project aims to build a new management paradigm for emerging risks as a set of principles supported by a common language, agreed tools and methods, and key performance indicators, all integrated into a single framework. It is using a number of Emerging Risk Representative Applications (ERRAs), or case studies, to inform the development of the framework; one of which concerns the carbon capture and storage (CCS) process. This paper describes the iNTeg-Risk CCS ERRA. Relevant hazards and properties of carbon dioxide are described and the emerging risks from CCS are discussed. Three new tools have been developed or trialled within the ERRA. These are: the DyPASI methodology for taking account of atypical (not usually identified) events during hazard identification; a methodology for including the time dimension in a risk assessment; and life-cycle approaches for risk management and communication. For CCS, the risk assessment needs to include both short-term potential accidents from capture, transport or injection, as well as very long term risks from storage. Knowledge gaps which are generic to emerging risks are also identified

Carbon capture and storage: a case study of emerging risk issues in the iNTeg-Risk project

This paper describes the iNTeg-Risk Carbon Capture and Storage (CCS) case study including: identification of example hazards in the CCS process including capture, transport, injection and storage; analysis using bow-tie techniques; modification of risk matrix approaches to include potential releases in the very long term from storage sites; use of life cycle analysis approaches; possible key performance indicators (KPIs); and knowledge gaps in terms of addressing emerging risk issues. One of the key features of the CCS case study is the need to include the time dimension in the risk assessment. The assessment needs to include both short-term potential accidents (from capture, transport or injection) as well as very long term risks from storage

Investigation of selective junctions using a newly developed tunnel current model for solar cell applications

International audienceCarrier transport through a tunnel barrier was modeled and implemented in the numerical device simulator AFORS-HET, which allows calculating the tunnel current between two semiconductor layers or between a metallic contact and a semiconductor layer. Rectangular barriers have been considered, for which an exact quantum solution for the transmission probability can be derived. The implementation in the simulation program was made by approximating the tunnel-interlayer as a “membrane” which modifies the current at the semiconductor/tunnel layer interface, without the need of inserting an additional insulator layer. It is demonstrated that this approximate description of the structure allows to simulate solar cells where tunneling across an insulator plays an important role. The model is then used to investigate new hole collector designs based on a tunnel oxide. It is shown, that the tunnel layer increases the selectivity of the contact for hole extraction, such that very high power conversion efficiencies can be reached

Patch pump versus conventional pump: postprandial glycemic excursions and the influence of wear time.

The aim of this study was to compare blood glucose and plasma insulin profiles after bolus insulin infusion by a patch pump (PP) versus a conventional pump (CP), directly after placement and after Day 3 of use. Twenty patients with type 1 diabetes came in for two blocks of visits: one block of two visits while wearing the OmniPod® (Insulet Corp., Bedford, MA) insulin pump (PP) and one block of two visits while wearing the Medtronic Diabetes (Northridge, CA) Paradigm® pump (CP). Patients administered an identical mealtime insulin bolus of at least 6 IU. For PP, maximum glucose levels were 28.7% lower on Day 3 (P=0.020), when maximum insulin levels were 30.3% higher (P=0.002). For CP, maximum glucose levels were 26.5% lower on Day 3 (P=0.015), when maximum insulin levels were 46.4% higher (P=0.003). Glucose levels (mean [interquartile range]) were significantly lower on Day 3 for PP (168.2 [145.8] mg/dL vs. 139.4 [77.8] mg/dL; P=0.013), but not significantly so for CP (159.0 [66.1] mg/dL vs. 139.5 [57.9] mg/dL; P=0.084). Mean insulin levels were significantly higher on Day 3 for CP (195 [120] pmol/L vs. 230 [90] pmol/L; P=0.01), but not significantly so for PP (178 [106] pmol/L vs. 194 [120] pmol/L; P=0.099). There were no significant differences between the two catheter lengths. Postprandial glycemic excursions were lower on Day 3 of catheter wear time, but there were no differences between PPs and CPs. These findings support the proposal that catheter wear time plays an important role in insulin absorptio