2-[2-(1H-Imidazol-3-ium-5-yl)eth­yl]-3-(pyridin-2-yl)-2H-imidazo[1,5-a]pyridin-4-ium bis­(perchlorate)

In the title mol­ecular salt, C17H17N5 +·2ClO4 −, the dihedral angles between the fused-ring system and the pendant five- and six-membered heterocyclic rings are 6.4 (2) and 41.29 (19)°, respectively. The O atoms of both perchlorate anions are disordered over two sets of sites with occupancy ratios of 0.614 (8):0.386 (8) and 0.591 (7):0.409 (7). An intra­molecular C—H⋯N contact occurs in the cation. In the crystal, the components are linked by N—H⋯O and C—H⋯O hydrogen bonds and π–π stacking inter­actions [centroid–centroid separation = 3.642 (3) Å]

Contact Lens Dosimetry of Solar Ultraviolet Radiation

Background: Ultraviolet radiation from the sun has been implicated in the pathogenesis of many ocular conditions. However, the amount of UV reaching the eye is not well defined. Methods: A contact lens made from the UV-sensitive plastic polysulphone was used to measure the dose of UV radiation at the surface of the eye for two subjects over six wearing trials. Results: The average ratio of UV radiation exposure at the surface of the eye to that of the UV radiation in the surrounding environment (ambient dose) was found to be 28 ± 9 per cent. The temporal UV dose appeared lower than both the central and nasal UV doses in five of the six wearing trials but these differences did not reach statistical significance. Conclusions: Contact lenses made from polysulphone can be used to estimate the regional dose of solar ultraviolet radiation

A decade of progress in critical care echocardiography: a narrative review.

INTRODUCTION: This narrative review focusing on critical care echocardiography (CCE) has been written by a group of experts in the field, with the aim of outlining the state of the art in CCE in the 10 years after its official recognition and definition. RESULTS: In the last 10 years, CCE has become an essential branch of critical care ultrasonography and has gained general acceptance. Its use, both as a diagnostic tool and for hemodynamic monitoring, has increased markedly, influencing contemporary cardiorespiratory management. Recent studies suggest that the use of CCE may have a positive impact on outcomes. CCE may be used in critically ill patients in many different clinical situations, both in their early evaluation of in the emergency department and during intensive care unit (ICU) admission and stay. CCE has also proven its utility in perioperative settings, as well as in the management of mechanical circulatory support. CCE may be performed with very simple diagnostic objectives. This application, referred to as basic CCE, does not require a high level of training. Advanced CCE, on the other hand, uses ultrasonography for full evaluation of cardiac function and hemodynamics, and requires extensive training, with formal certification now available. Indeed, recent years have seen the creation of worldwide certification in advanced CCE. While transthoracic CCE remains the most commonly used method, the transesophageal route has gained importance, particularly for intubated and ventilated patients. CONCLUSION: CCE is now widely accepted by the critical care community as a valuable tool in the ICU and emergency department, and in perioperative settings

Early Cenozoic Stratigraphy of the Equatorial Pacific and the Eocene Revealed (abstract of paper presented at AGU Fall Meeting, San Francisco, 6-10 Dec 2002)

The broad mound of sediments found in the equatorial Pacific contains a detailed and complex record of the history of equatorial divergence, trade wind strength, biogeochemical fluxes, and biologic evolution. To extract this history from the biogenic sediments of this region the recovery of undisturbed and complete sections is required. Also required is the development of a detailed chronostratigraphy with which we can determine both the times and rates of paleoceanographic and paleoclimatic change. As this mound of sediment has ridden northward on the Pacific crust the most biogenic parts of the lower Cenozoic sediments have gradually moved from under the region of high flux rates at the divergence center. Now they lie within the reach of APC coring on the JOIDES Resolution. The sections recovered on Leg 199 form a paleolatitude transect from about 4.5$°S to 18.5$°N. Study of these sections has given us a well documented magnetic stratigraphy back into the Eocene, good calcareous nannofossil stratigraphy for the lower Miocene, Oligocene, and early Eocene, and excellent radiolarian stratigraphy from the lower Miocene through the middle Eocene. In addition we recovered good the Miocene/Oligocene and Eocene/Oligocene boundaries in an equatorial setting and LPTM sections near basement at three different sites. These results have allowed a more certain assignment of ages of biostratigraphic events and an opportunity to develop orbitally tuned time scales in sections from the lower Miocene down through the Oligocene. The initial estimates of sediment accumulation rates in the radiolarian oozes indicate variation by a factor of three from upper to middle Eocene times. Mapped patterns of sediment accumulation in the Eocene using both ODP Leg 199 and older DSDP data indicate at least two latitudinal zones of maxima in accumulation rates. Determination of the exact latitudes of these zones awaits further study