Radar echo characteristics at Ny-Alesund, Svalbard and Arctic storms over the Norwegian Sea

This paper is a preliminary report on radar echo characteristics and Arctic storms near Svalbard. Using an X-band vertically pointing radar data at Ny-Alesund, Svalbard, Norway and synoptic weather charts, the radar echo characteristics are investigated for one year between April 1994 and March 1995. Radar echoes have distinct seasonal variations with respect to height. Taking account of synoptic conditions, each series of radar echoes is classified into four patterns and it is found that they have strong seasonal variations. The low pressure system echo patterns appear throughout the year; their appearance frequencies exceed 50 of all radar echo appearances and increase in early summer and early winter. The appearance frequencies of low pressure systems over the Norwegian Sea have also characteristic strong seasonal variations. These low pressure activities appear to be related to precipitation behavior at Ny-Alesund and vapor transportation to the high Arctic from lower latitudes

The dihydropyridine calcium channel blocker benidipine prevents lysophosphatidylcholine-induced endothelial dysfunction in rat aorta

<p>Abstract</p> <p>Background</p> <p>Lysophosphatidylcholine (LPC), an atherogenic component of oxidized low-density lipoprotein, has been shown to induce the attenuation of endothelium-dependent vascular relaxation. Although benidipine, a dihydropyridine-calcium channel blocker, is known to have endothelial protective effects, the effects of benidipine on LPC-induced endothelial dysfunction remain unknown. We examined the effects of benidipine on the impairment of endothelium-dependent relaxation induced by LPC.</p> <p>Methods</p> <p>Benidipine was administered orally to rats and aortas were then isolated. Aortic rings were treated with LPC and endothelial functions were then evaluated. Additionally, the effects of benidipine on intracellular calcium concentration ([Ca²⁺]_i) and membrane fluidity altered by LPC in primary cultured rat aortic endothelial cells were examined. [Ca²⁺]_iwas measured using the fluorescent calcium indicator fura-2. Membrane fluidity was monitored by measuring fluorescence recovery after photobleaching.</p> <p>Results</p> <p>Treatment with LPC impaired endothelial function. Benidipine prevents the impairment of relaxation induced by LPC. Acetylcholine elicited an increase in [Ca²⁺]_iin fura-2 loaded endothelial cells. The increase in [Ca²⁺]_iwas suppressed after exposure to LPC. Plasma membrane fluidity increased following incubation with LPC. Benidipine inhibited the LPC-induced increase in membrane fluidity and impairment of increase in [Ca²⁺]_i.</p> <p>Conclusion</p> <p>These results suggest that benidipine inhibited LPC-induced endothelial dysfunction by maintaining increase in [Ca²⁺]_i. Benidipine possesses membrane stabilization properties in LPC-treated endothelial cells. It is speculated that the preservation of membrane fluidity by benidipine may play a role in the retainment of calcium mobilization. The present findings may provide new insights into the endothelial protective effects of benidipine.</p

Variation of dimethylsulfide mixing ratio over the Southern Ocean from 36°S to 70°S

AbstractAtmospheric dimethylsulfide (DMS) was measured to investigate the variation in its concentration over sea ice free oceans and sea ice regions of the Southern Ocean, using a proton transfer reaction-mass spectrometer (PTR-MS) on board the icebreaker Shirase from 1 December 2009 to 16 March 2010. In general, DMS concentrations over sea ice regions were very low compared with those over the sea ice free ocean. However, abrupt increases in DMS concentrations occurred over sea ice regions while the ship was moving and crushing the sea ice. Undoubtedly, the elevated DMS concentrations were caused by large DMS emissions from gaps in the ice made by the ship. During the period when Shirase had anchored off Syowa Station (69°00.4′S, 39°35.3′E), Antarctica, DMS concentrations were not detected. At this time, the surrounding sea of East Ongul island, on which Syowa Station is located, was completely covered with multi-year fast ice. Sea ice probably inhibits DMS emission from the ocean to the atmosphere. In addition, there was no evidence that chlorophyll a concentration in the sea water or wind speed above the sea surface affect atmospheric DMS concentrations over the sea ice free ocean regions