Generation of the pitch moment during the controlled flight after takeoff of fruitflies.

In the present paper, the controlled flight of fruitflies after voluntary takeoff is studied. Wing and body kinematics of the insects after takeoff are measured using high-speed video techniques, and the aerodynamic force and moment are calculated by the computational fluid dynamics method based on the measured data. How the control moments are generated is analyzed by correlating the computed moments with the wing kinematics. A fruit-fly has a large pitch-up angular velocity owing to the takeoff jump and the fly controls its body attitude by producing pitching moments. It is found that the pitching moment is produced by changes in both the aerodynamic force and the moment arm. The change in the aerodynamic force is mainly due to the change in angle of attack. The change in the moment arm is mainly due to the change in the mean stroke angle and deviation angle, and the deviation angle plays a more important role than the mean stroke angle in changing the moment arm (note that change in deviation angle implies variation in the position of the aerodynamic stroke plane with respect to the anatomical stroke plane). This is unlike the case of fruitflies correcting pitch perturbations in steady free flight, where they produce pitching moment mainly by changes in mean stroke angle.

A Meta-analysis Reveals S-1-based Chemotherapy Improves the Survival of Patients With Advanced Gastric Cancer.

The aim of this study was to compare the efficacy and safety of S-1-based therapy versus non-S-1-based therapy in advanced gastric cancer (AGC) patients.Eligible studies stratifying objective response rate (ORR), progression-free survival (PFS), overall survival (OS), and adverse events (AEs) in AGC patients were identified from Embase, Pubmed, Cochrane Library, and China National Knowledge Infrastructure databases. The STATA package (version 11.0) was used to pool the data from the eligible studies.Fifteen studies with 2973 AGC cases, of which 1497 (50.4%) received S-1-based therapy and 1476 (49.6%) received non-S-1-based therapy, were identified in the meta-analysis. AGC patients who had received S-1-based therapy had a higher median OS, median PFS, and ORR than those who had received 5-fluorouracil (FU)-based therapy (OS: hazard ratio [HR] 0.89, 95% confidence interval [CI] 0.80-0.98, P = 0.015; PFS: HR 0.88, 95% CI 0.80-0.98, P = 0.016; ORR: OR 1.25, 95% CI 1.08-1.45, P = 0.003, respectively). S-1-based therapy had similar efficacy to capecitabine-based therapy in terms of median OS (HR 1.14, 95% CI 0.91-1.41, P = 0.253), median PFS (HR 1.01, 95% CI 0.82-1.25, P = 0.927), and ORR (OR 0.84, 95% CI 0.63-1.12, P = 0.226). Subgroup analysis for grade 3 to 4 toxicity showed higher incidence of neutropenia (relative risk [RR] = 0.827, P = 0.006), nausea (RR = 0.808, P = 0.040), and lower diarrhea (RR = 1.716, P = 0.012) in 5-FU-based arm, and higher diarrhea (RR = 0.386, P = 0.007) in capecitabine-based arm.S-1-based chemotherapy is favorable to AGC patients with better clinical benefit than 5-FU-based chemotherapy and with equivalent antitumor compare with capecitabine-based therapy.

Wing and body motion and aerodynamic and leg forces during take-off in droneflies.

Here, we present a detailed analysis of the take-off mechanics in droneflies performing voluntary take-offs. Wing and body kinematics of the insects during take-off were measured using high-speed video techniques. Based on the measured data, the inertia force acting on the insect was computed and the aerodynamic force of the wings was calculated by the method of computational fluid dynamics. Subtracting the aerodynamic force and the weight from the inertia force gave the leg force. In take-off, a dronefly increases its stroke amplitude gradually in the first 10-14 wingbeats and becomes airborne at about the 12th wingbeat. The aerodynamic force increases monotonously from zero to a value a little larger than its weight, and the leg force decreases monotonously from a value equal to its weight to zero, showing that the droneflies do not jump and only use aerodynamic force of flapping wings to lift themselves into the air. Compared with take-offs in insects in previous studies, in which a very large force (5-10 times of the weight) generated either by jumping legs (locusts, milkweed bugs and fruit flies) or by the 'fling' mechanism of the wing pair (butterflies) is used in a short time, the take-off in the droneflies is relatively slow but smoother.