Grain size limits derived from 3.6 {\mu}m and 4.5 {\mu}m coreshine

Recently discovered scattered light from molecular cloud cores in the wavelength range 3-5 {\mu}m (called "coreshine") seems to indicate the presence of grains with sizes above 0.5 {\mu}m. We aim to analyze 3.6 and 4.5 {\mu}m coreshine from molecular cloud cores to probe the largest grains in the size distribution. We analyzed dedicated deep Cycle 9 Spitzer IRAC observations in the 3.6 and 4.5 {\mu}m bands for a sample of 10 low-mass cores. We used a new modeling approach based on a combination of ratios of the two background- and foreground-subtracted surface brightnesses and observed limits of the optical depth. The dust grains were modeled as ice-coated silicate and carbonaceous spheres. We discuss the impact of local radiation fields with a spectral slope differing from what is seen in the DIRBE allsky maps. For the cores L260, ecc806, L1262, L1517A, L1512, and L1544, the model reproduces the data with maximum grain sizes around 0.9, 0.5, 0.65, 1.5, 0.6, and > 1.5 {\mu}m, respectively. The maximum coreshine intensities of L1506C, L1439, and L1498 in the individual bands require smaller maximum grain sizes than derived from the observed distribution of band ratios. Additional isotropic local radiation fields with a spectral shape differing from the DIRBE map shape do not remove this discrepancy. In the case of Rho Oph 9, we were unable to reliably disentangle the coreshine emission from background variations and the strong local PAH emission. Considering surface brightness ratios in the 3.6 and 4.5 {\mu}m bands across a molecular cloud core is an effective method of disentangling the complex interplay of structure and opacities when used in combination with observed limits of the optical depth.Comment: 23 pages, 18 figures, accepted for publication in A&

Impaired insulin-stimulated phosphorylation of Akt and AS160 in skeletal muscle of women with polycystic ovary syndrome is reversed by pioglitazone treatment

  Udgivelsesdato: 2008-FebOBJECTIVE: Insulin resistance in skeletal muscle is a major risk factor for type 2 diabetes in women with polycystic ovary syndrome (PCOS). However, the molecular mechanisms underlying skeletal muscle insulin resistance and the insulin-sensitizing effect of thiazolidinediones in PCOS in vivo are less well characterized. RESEARCH DESIGN AND METHODS: We determined molecular mediators of insulin signaling to glucose transport in skeletal muscle biopsies of 24 PCOS patients and 14 matched control subjects metabolically characterized by euglycemic-hyperinsulinemic clamps and indirect calorimetry, and we examined the effect of 16 weeks of treatment with pioglitazone in PCOS patients. RESULTS: Impaired insulin-mediated total (R(d)) oxidative and nonoxidative glucose disposal (NOGD) was paralleled by reduced insulin-stimulated Akt phosphorylation at Ser473 and Thr308 and AS160 phosphorylation in muscle of PCOS patients. Akt phosphorylation at Ser473 and Thr308 correlated positively with R(d) and NOGD in the insulin-stimulated state. Serum free testosterone was inversely related to insulin-stimulated R(d) and NOGD in PCOS. Importantly, the pioglitazone-mediated improvement in insulin-stimulated glucose metabolism, which did not fully reach normal levels, was accompanied by normalization of insulin-mediated Akt phosphorylation at Ser473 and Thr308 and AS160 phosphorylation. AMPK activity and phosphorylation were similar in the two groups and did not respond to pioglitazone in PCOS patients. CONCLUSIONS: Impaired insulin signaling through Akt and AS160 in part explains insulin resistance at the molecular level in skeletal muscle in PCOS, and the ability of pioglitazone to enhance insulin sensitivity involves improved signaling through Akt and AS160. Moreover, our data provide correlative evidence that hyperandrogenism in PCOS may contribute to insulin resistanc

The role of E1-E2 interplay in multiphonon Coulomb excitation

In this work we study the problem of a charged particle, bound in a harmonic-oscillator potential, being excited by the Coulomb field from a fast charged projectile. Based on a classical solution to the problem and using the squeezed-state formalism we are able to treat exactly both dipole and quadrupole Coulomb field components. Addressing various transition amplitudes and processes of multiphonon excitation we study different aspects resulting from the interplay between E1 and E2 fields, ranging from classical dynamic polarization effects to questions of quantum interference. We compare exact calculations with approximate methods. Results of this work and the formalism we present can be useful in studies of nuclear reaction physics and in atomic stopping theory.Comment: 10 pages, 6 figure

Primary Percutaneous Coronary Intervention as a National Reperfusion Strategy in Patients With ST-Segment Elevation Myocardial Infarction

Background— In Denmark, primary percutaneous coronary intervention (PPCI) was chosen as a national reperfusion strategy for patients with ST-segment elevation myocardial infarction in 2003. This study describes the temporal implementation of PPCI in Western Denmark, the gradual introduction of field triage for PPCI (patients rerouted from the scene of the event directly to the invasive center), and the associated outcome. Methods and Results— The study population comprised 9514 patients treated with PPCI from 1999 to 2009 with symptom duration ≤12 hours and either a delay from the emergency medical service (EMS) call to PPCI (healthcare system delay) of ≤6 hours or as self-presenters. The median follow-up time was 3.7 years. The number of patients treated with PPCI increased from 190 in 1999 to 1212 in 2009. Among patients transported by the EMS from the scene of the event, the proportion who were field triaged directly to a PCI center increased from 33% (34/103) to 72% (616/851, P &lt;0.001). Patients who were field triaged had lower long-term mortality, with adjusted hazard ratios (95% CI) of 1.26 (1.12–1.43) among patients transported by the EMS to a local hospital and then transferred, 1.28 (1.10–1.49) among patients self-presenting at a local hospital and then transferred, and 1.37 (1.18–1.58) among patients self-presenting at a PCI center. Conclusions— A reperfusion strategy with PPCI only for patients with ST-segment elevation myocardial infarction was successfully implemented in Western Denmark, and the majority of patients transported by the EMS are now triaged directly to the PPCI centers. This strategy is associated with lower mortality. </jats:sec