Slow-light enhanced optical detection in liquid-infiltrated photonic crystals

Slow-light enhanced optical detection in liquid-infiltrated photonic crystals is theoretically studied. Using a scattering-matrix approach and the Wigner-Smith delay time concept, we show that optical absorbance benefits both from slow-light phenomena as well as a high filling factor of the energy residing in the liquid. Utilizing strongly dispersive photonic crystal structures, we numerically demonstrate how liquid-infiltrated photonic crystals facilitate enhanced light-matter interactions, by potentially up to an order of magnitude. The proposed concept provides strong opportunities for improving existing miniaturized absorbance cells for optical detection in lab-on-a-chip systems.Comment: Paper accepted for the "Special Issue OWTNM 2007" edited by A. Lavrinenko and P. J. Robert

The blood volumes of the primary and secondary circulatory system in the Atlantic cod Gadus morhua L., using plasma bound Evans Blue and compartmental analysis

The volume of the primary (PCS) and secondary (SCS) circulatory system in the Atlantic cod Gadus morhua was determined using a modified dye dilution technique. Cod (N=10) were chronically cannulated in the second afferent branchial artery with PE-50 tubing. Evans Blue dye was bound to harvested fish plasma at a concentration of 1 mg dye ml(-1) plasma, and injected at a concentration of 1 mg kg(-1) body mass. Serial sampling from the cannula produced a dye dilution curve, which could be described by a double exponential decay equation. Curve analysis enabled the calculation of the primary circulatory and total distribution volume. The difference between these volumes is assumed to be the volume of the SCS. From the dilution curve, it was also possible to calculate flow rates between and within the systems. The results of these experiments suggest a plasma volume in the PCS of 3.42+/-0.89 ml 100 g(-1) body mass, and in the SCS of 1.68+/-0.35 ml 100 g(-1) body mass (mean +/- S.D.) or approximately 50% that of the PCS. Flow rates to the SCS were calculated as 2.7% of the resting cardiac output. There was an allometric relationship between body mass and blood volumes. Increasing condition factor showed a tendency towards smaller blood volumes of the PCS, expressed as percentage body mass, but this was not evident for the volume of the SCS

Magnetization of Greenland ice and its relationship with dust content

[1] We estimate the concentration of fine magnetic particles in ice samples from the North Greenland Ice Core Project core from the central Greenland ice sheet, using lowtemperature (77K) isothermal remanent magnetization (IRM) analysis and compare it with the mass concentration of aerosol dust. Samples were taken from six climatic intervals, spanning the time from the Holocene (Preboreal) back to the Last Glacial Dansgaard/ Oeschger cycle 5. The mean IRM intensity of the ice varies by a factor of 3 from glacial to interglacial stages, being lower during interglacials. The IRM acquisition curves of the ice do not quite saturate at the maximum available field of 0.8 T and show a relatively broad coercivity, which is compatible with a mixture of maghemite or magnetite and hematite. Comparison of the IRM intensity and total dust mass shows a remarkably good correlation but also reveals a large background magnetization, which may be essentially constant over the different climatic stages. IRM suggests that the dust properties are independent of the background signal and that the dust aerosol has a magnetization within about 30% of pristine loess from the Chinese Loess Plateau, which is considered to have the same source in the same east Asian deserts as dust in Greenland ice. Ice contamination and the flux of extraterrestrial dust particles were considered in order to explain the origin of the background magnetization. Nevertheless, we could not find a convincing explanation for this signal, which represents a considerable part of the IRM signal and is the dominant component during interglacial intervals, without invoking the presence of undetected dust mass. The alternative hypothesis of a varying magnetization of the ice dust at different climatic periods would suggest that different sources of aerosol are active during different climatic periods. This, however, has not proven to be the case so far for studies of the provenance of dust in Greenland ice

2,4-Bis(morpholin-4-yl)-6-phen­oxy-1,3,5-triazine

In the title compound, C17H21N5O3, the dihedral angle between the triazine and the phenyl ring is 80.31 (11)°. One of the morpholine rings is disordered over two orientations with site occupancies of 0.762 (10) and 0.238 (10). Both morpholine rings in the mol­ecule adopt chair conformations

Effect of ischemic preconditioning and a Kv7 channel blocker on cardiac ischemia-reperfusion injury in rats

Recently, we found cardioprotective effects of ischemic preconditioning (IPC), and from a blocker of KCNQ voltage-gated K+ channels (KV7), XE991 (10,10-bis(4-pyridinylmethyl)-9(10H)-anthracenone), in isolated rat hearts. The purpose of the present study was to investigate the cardiovascular effects of IPC and XE991 and whether they are cardioprotective in intact rats. In conscious rats, we measured the effect of the KV7 channel blocker XE991 on heart rate and blood pressure by use of telemetry. In anesthetized rats, cardiac ischemia was induced by occluding the left coronary artery, and the animals received IPC (2 × 5 min of occlusion), XE991, or a combination. After a 2 h reperfusion period, the hearts were excised, and the area at risk and infarct size were determined. In both anesthetized and conscious rats, XE991 increased blood pressure, and the highest dose (7.5 mg/kg) of XE991 also increased heart rate, and 44% of conscious rats died. XE991 induced marked changes in the electrocardiogram (e.g., increased PR interval and prolonged QTC interval) without changing cardiac action potentials. The infarct size to area at risk ratio was reduced from 53 ± 2% (n = 8) in the vehicle compared to 36 ± 3% in the IPC group (P < 0.05, n = 9). XE991 (0.75 mg/kg) treatment alone or on top of IPC failed to reduce myocardial infarct size. Similar to the effect in isolated hearts, locally applied IPC was cardioprotective in intact animals exposed to ischemia-reperfusion. Systemic administration of XE991 failed to protect the heart against ischemia-reperfusion injury suggesting effects on the autonomic nervous system counteracting the cardioprotection in intact animals. © 2019 Elsevier B.V.Aarhus Universitets ForskningsfondHjerteforeningen: 17-R116-A7616-22074K. Corydon was supported by a scholarship from Aarhus University Research Foundation , U. Simonsen and E.R. Hedegaard were supported by the Danish Heart Foundation (grant 17-R116-A7616-22074 ). The study was also supported by Jens Anker Andersens Foundation, Helge and Peter Kornings Foundation, Direktør Kurt Bønnelycke and wife Mrs Grethe Bønnelyckes Foundation, Helge Peetz and Verner Peetz and wife Vilma Peetz grant. Appendix