Drafting behaviors in fish induced by a local pressure drop around a hydrofoil model.

Fish schooling has the improvement in hydrodynamic propulsive efficiency through the interaction of flow field induced by fish bodies and tail beat. Such energy-saving behaviors due to flow interactions also occur with changes in the flow field caused by structures. We examined the differences between a live fish swimming around a streamlined hydrofoil model prepared to represent fish body and swimming alone in a flow tank. We observed that the fish can remain in the same place without tail beating. It called "drafting" behavior. The analysis of fish drafting showed that fish obtained thrust using a local pressure drop caused by the high velocity flow even in the vicinity of the hydrofoil model at an angle of attack α of 10° to 20°without flow separation, and fish balanced forces by using an α of fish body. This tendency was confirmed in the model experiment using a two-axis load cell, and the forces acting on the fish body was the smallest value when the fish model was placed in the same conditions as a live fish experiment. We also confirmed by simulation and found that the α of fish body generated lift force and counteract the suction force. Above results indicate that a fish can balance the anterior-posterior and lateral direction forces by using a local pressure drop around a hydrofoil model as suction force, and using angle of attack on its body, thereby realizing drafting.

A case of secondary leukemia subsequent to myelodysplastic syndromes successfully treated with azacitidine.

Elderly patients with secondary acute myeloid leukemia (AML) following myelodysplastic syndrome (MDS) are often medically unfit for or resistant to chemotherapy, and their prognosis is dismal. In the present paper, we reported a case of secondary leukemia following MDS in an 80-year-old male patient who was deemed unfit for chemotherapy owing to his old age and poor physical condition. Despite a high tumor burden, treatment with AZA exerted a remarkable response, leading to an immediate cytoreduction in our case. Our results suggest that AZA can be an attractive therapeutic option for elderly MDS or AML patients, offering adequate efficacy and high tolerability.

Successful allogeneic hematopoietic stem cell transplantation in a young patient with Richter syndrome presenting with chronic lymphocytic leukemia and diffuse large B-cell lymphoma with different cell origins.

A 32-year-old woman was referred to our hospital due to systemic lymphadenopathy. The patient's peripheral blood showed expansion of CD5+CD20+ CD38+ CD23- mature lymphocytes. However, the axillary lymph nodes were infiltrated by both CD23+ large lymphocytes and CD23- small lymphocytes. Because the pattern of the rearranged immunoglobulin heavy chain gene was different between the peripheral blood and lymph node samples in a Southern blot analysis, the patient was diagnosed with Richter syndrome, in which diffuse large B-cell lymphoma develops from a clone distinct from B-cell chronic lymphocytic leukemia. After undergoing rituximab, cyclophosphamide, doxorubicin, vincristine and prednisolone (R-CHOP) therapy, the patient was successfully treated with allogeneic hematopoietic transplantation, and no relapse was observed for three years.