Variation in the diatom community under fast ice near Syowa Station, Antarctica, during the austral summer of 1997/98

Variations in abundance and community structure of diatoms under the fast ice near Syowa Station were investigated almost daily during the austral summer of 1997/98. Two periods of high chlorophyll a concentration were observed throughout the study : from the end of December to early January and from the middle to the end of January. Size fractionation of chlorophyll a revealed that phytoplankton during the former period consisted mostly of organisms larger than 20μm and during the latter period, 10-20μm. The large diatoms, Porosira pseudodenticulata and Pseudonitzschia turgiduloides, and small diatoms, Fragilariopsis spp., were the dominant organisms in the former and latter periods, respectively. Melting of the fast ice occurred in January, indicating a possibility that small sized diatoms were released from the ice to the water column. Accumulation of small diatoms in a sediment trap followed a decrease of their abundance in the water column. These results indicate that most of the ice algae detached from the ice sank directly to the bottom during the latter half of the austral summer

Japanese perspective in surgery for thoracoabdominal aortic aneurysms

Objective: Operative mortality and morbidity after thoracoabdominal aortic surgery remain high. We report our strategy and outcomes, especially those of spinal cord protection. Methods: Outcomes of 178 patients (age: 26-88 years) who underwent thoracoabdominal aortic replacement were retrospectively analyzed. 65 had aortic dissection, 14 had infected aneurysms, and 22 presented with rupture. Operations were non-elective in 24 and redo through re-thoracotomy in 21. Extent of replacement was Crawford-I in 39, II in 26, III in 78, and IV in 35. Staged repair was recently preferred, which resulted in decrease in extent II repair and increase in redo since 2009. Operations were performed under distal aortic perfusion and multi-segmental sequential repair to maximize collateral blood flow, and deep hypothermic circulatory arrest was preserved for those requiring open aortic anastomosis (n = 20). A total of 166 separate grafts were used for intercostal reconstruction in 88 patients, which was guided by preoperative feeding artery localization. Their patency was studied by postoperative MD-CT in 74 patients for 145 grafts. Results: There were 3.9% hospital mortality and 5.1% spinal cord injury. Preoperative feeding artery localization resulted in reduced number of reconstruction and improved patency, and grafts connecting to the feeding artery were patent in 92%. Results of redo operations were not different (no mortality and spinal cord injury) from the de novo operations. Conclusions: Our concept of spinal cord protection, which was based on selective intercostal reconstruction while maximizing spinal cord collateral blood flow, seems justified