Effect of Hindwings on the Aerodynamics and Passive Dynamic Stability of a Hovering Hawkmoth

Insects are able to fly stably in the complex environment of the various gusts that occur in nature. In addition, many insects suffer wing damage in their lives, but many species of insects are capable of flying without their hindwings. Here, we evaluated the effect of hindwings on aerodynamics using a Navier-Stokes-based numerical model, and then the passive dynamic stability was evaluated by coupling the equation of motion in three degrees of freedom with the aerodynamic forces estimated by the CFD solver under large and small perturbation conditions. In terms of aerodynamic effects, the presence of the hindwings slightly reduces the efficiency for lift generation but enhances the partial LEV circulation and increases the downwash around the wing root. In terms of thrust, increasing the wing area around the hindwing region increases the thrust, and the relationship is almost proportional at the cycle-averaged value. The passive dynamic stability was not clearly affected by the presence of the hindwings, but the stability was slightly improved depending on the perturbation direction. These results may be useful for the integrated design of wing geometry and flight control systems in the development of flapping-winged micro air vehicles.

Impact of in-hospital medical management for COVID-19 pandemic on door-to-balloon time in patients with ST-elevation myocardial infarction

Background

Delayed door-to-balloon (DTB) time and deterioration of in-hospital mortality during the coronavirus disease 2019 (COVID-19) pandemic have been reported. Little is known about the impact of changes in in-hospital medical management before primary percutaneous coronary intervention (PCI) for COVID-19 such as screening test (antigen or polymerase chain reaction (PCR) tests, chest CT for excluding the pneumoniae) and primary PCI under full personal protective equipment (PPE) on DTB time and in-hospital mortality.

Purpose

The purpose of this study was to evaluate the impact of in-hospital medical management for COVID-19 on DTB time and in-hospital mortality during COVID-19 pandemic period.

Methods

We compared DTB time and in-hospital mortality of 502 ST-elevation myocardial infarction (STEMI) patients during COVID-19 pandemic (February 2020 and January 2021) with 2035 STEMI patients before pandemic (February 2016 and January 2020) using date from Mie ACS registry, a retrospective and multicenter registry.

Results

The COVID-19 screening tests before primary PCI and/or primary PCI under full PPE was performed on 173/502 (34.5%) patients (antigen or PCR tests; 39 (7.8%), chest CT; 156 (31.3%), full PPE; 11 (2.2%)). These patients had lower rate of achievement of DTB time ≤90 min compared with others (Figure 1A). Moreover, In-hospital management of COVID-19 screening tests and/or primary PCI under full PPE was an independent factor of DTB time>90 min with odds ratio of 1.94 (95% confidential interval: 1.37–2.76, p<0.001). In addition, in-hospital mortality of those patients was higher compared with others (Figure 1B).

Conclusion

In-hospital medical management for COVID-19 screening tests before primary PCI and/or primary PCI under full PPE was the independent factor of DTB time>90 min. This study reinforces the need to focus efforts on shortening DTB time, while controlling the epidemic of infection.

Funding Acknowledgement

Type of funding sources: None.

Auditory sensory range of male mosquitoes for the detection of female flight sound

Male mosquitoes detect and localize conspecific females by their flight-tones using the Johnston's organ (JO), which detects antennal deflections under the influence of local particle motion. Acoustic behaviours of mosquitoes and their JO physiology have been investigated extensively within the frequency domain, yet the auditory sensory range and the behaviour of males at the initiation of phonotactic flights are not well known. In this study, we predict a maximum spatial sensory envelope for flying Culex quinquefasciatus by integrating the physiological tuning response of the male JO with female aeroacoustic signatures derived from numerical simulations. Our sensory envelope predictions were tested with a behavioural assay of free-flying males responding to a female-like artificial pure tone. The minimum detectable particle velocity observed during flight tests was in good agreement with our theoretical prediction formed by the peak JO sensitivity measured in previous studies. The iso-surface describing the minimal detectable particle velocity represents the quantitative auditory sensory range of males and is directional with respect to the female body orientation. Our results illuminate the intricacy of the mating behaviour and point to the importance of observing the body orientation of flying mosquitoes to understand fully the sensory ecology of conspecific communication.

Horizontal orientation facilitates pollen transfer and rain damage avoidance in actinomorphic flowers of Platycodon grandiflorus

In zoophilous plants, floral orientation evolved under both biotic and abiotic pressure to enhance pollination success. However, the adaptive significance of horizontal orientation in radially symmetrical (actinomorphic) flowers remains largely unknown, although that of bilaterally symmetrical flowers has been well studied. We experimentally altered floral angle in a population of insect-pollinated Platycodon grandiflorus flowers to examine the effects of floral orientation on pollinator behaviour, pollination success and pollen rain damage avoidance. To further investigate the potential pollen damage by rain, we obtained past precipitation records for the study area during the flowering season, and experimentally tested P. grandiflorus pollen damage by water. Horizontally oriented flowers received more pollinator visits and had pollen grains on the stigma in male and/or female phases than downward- and/or upward-oriented flowers and avoided pollen damage by rainfall better than upward-oriented flowers. A pollen germination experiment showed that approximately 30% of pollen grains burst in distilled water, indicating that pollen damage by rainfall may be significant in P. grandiflorus. Our field experiments revealed that upward-oriented flowers cannot avoid pollen damage by rainfall during the flowering period, and that both upward- and downward-oriented flowers experience pollinator limitation in female success. Therefore, horizontal flower orientation appears to be adaptive in this insect-pollinated actinomorphic species that blooms during the rainy season.

Biomimetic Soft Wings for Soft Robot Science

Flight and swimming in nature can inspire the design of highly adaptive robots capable of working in complex environments. In this letter, we reviewed our work on robotic propulsion in the air and water, with a specific focus on the crucial functions of elastic components involved in the driving mechanism and flapping wings. Elasticity in the driving mechanism inspired by birds and insects can enhance both the aerodynamic efficiency of flapping wings and robustness against disturbances with appropriate design. A flapping wing surface with a stiffness distribution inspired by hummingbirds was fabricated by combining tapered spars and ribs with a thin film. The biomimetic flexible wing could generate more lift than the nontapered wing with a similar amount of power consumption. Underwater flapping-wing propulsion inspired by penguins was investigated by combining the 3-degree-of-freedom (DoF) flapping mechanism and hydrodynamic calculation, which indicates that wing bending increases the propulsion efficiency. This work demonstrates the importance of passive deformation of both wing surfaces and driving mechanisms for improving the fluid dynamic efficiency and robustness in flight and swimming, as well as providing biological insight from an engineering perspective.

Expression and roles of N-type Ca channel in cardiaomyocytes

Background

Voltage dependent Ca channels are divided to L-, T-, N-, P/Q-, and R-types, and N-type Ca channel (NCC) is mainly expressed in nerve terminal and regulates neurotransmitter release. Recently, NCC has been reported to express in adrenal gland and renal tubular cells. We examined whether NCC is expressed in cardiac myocytes and if so, the roles of this channel.

Methods

Expression of NCC mRNA and protein in cardiomyocytes were assessed by quantitative real time PCR and Western blot analysis using neonatal rat cultured cardiomyocytes, infant, and adult rat hearts. Expression site of NCC in cardiomyocytes was examined by confocal imaging of immunofluorescent staining. The roles of NCC in physiological Ca transient in neonatal myocytes were examined using fluorescence imaging of Fluo4, an intracellular Ca indicator. To examine the effects of pathological condition, such as heart failure and ischemia-reperfusion, on NCC expression, cultured cardiomyocytes were treated with norepinephrine (10 μmol/L, 24 hours) or subjected to 5 hours of hypoxia followed by 30 minutes of reoxygenation. In addition, adult rats were subjected to myocardial infarction by ligating the left anterior coronary artery. Lethal myocyte injury was examined by LDH activity in culture medium and myocyte apoptosis was examined by nuclear staining with DAPI and caspase 3 activity. To clarify the roles of NCC in neonatal myocytes in these pathological conditions, we examine the effect of ω-conotoxin, a selective NCC blocker.

Results

NCC mRNA and protein were expressed in neonatal cardiomyocytes. Immunocytochemical staining showed NCC was expressed in myocyte plasma membrane. During physiological spontaneous beating, ω-conotoxin did not affect beating rate and intra cellular Ca transient, suggesting that the roles of NCC on physiological beating are little. After birth level of NCC mRNA expression in cardiac tissue gradually decreased within 2 weeks and low level of mRNA expressed continuously in adult cardiac tissue. However, in pathological condition, mRNA and protein levels of NCC in non-infarcted region were increased 4 weeks after myocardial infarction. In addition, hypoxia-reoxygenation and norepinephrine administration increased LDH release and myocyte apoptosis in association with increase in NCC expression in neonatal cultured myocytes. ω-conotoxin significantly suppressed hypoxia/reoxygenation- and norepinephrine-induced LDH release and caspase 3 activation.

Conclusion

NCC is expressed in neonatal cardiac myocytes and the expression level was decreased after birth. Pathological condition, such as ischemic heart disease and heart failure, upregulated NCC expression in cardiomyocytes and NCC exacerbated lethal myocyte injury, while roles of NCC in physiological beating are little.

Funding Acknowledgement

Type of funding sources: None.

Improvement of abnormal cervical cytology possibly due to a graft-versus-tumor effect: A case report and literature review

The cervical cytology of our patient transformed from squamous cell carcinoma to negative for intraepithelial lesion or malignancy, possibly due to the graft-versus-tumor effect following allogeneic stem cell transplantation.

Aeroacoustic characteristics of owl-inspired blade designs in a mixed flow fan: effects of leading- and trailing-edge serrations

There is an increasing need in industry for noise reduction in fans. Inspired by owls' silent flight, we propose four owl-inspired blade designs for a mixed-flow fan to examine whether leading-edge (LE) and/or trailing-edge (TE) serrations can resolve the tradeoff between sound suppression and aerodynamic performance. We investigate the blades' aeroacoustic characteristics through various experimental methods and large-eddy simulation (LES)-based numerical analyses. Experimental results suggest that 'slotted', simply-fabricated LE serrations can achieve a lowering of the noise level while sustaining the aerodynamic performance of the fan, whereas TE serrations fail. In addition, the inclination angle can improve LE serration performance in aeroacoustic and aerodynamic performance with a reduction in the specific noise level by around 1.4 dB. LES results and noise spectral analysis indicate that the LE serrations can suppress flow separation, reducing the broadband noise at low-to-middle frequencies (40-4k Hz). This passive-flow-control mechanism, likely due to local higher incidence angles associated with LE serrations, is capable of alleviating the intensive pressure gradient while suppressing wall-pressure fluctuations over the LE region, hence weakening the Kelvin-Helmholtz instability. The tonal noise also shows a marked reduction at the highest peak frequency associated with fan-vane interaction. Moreover, we find that the high-frequency noise by-product radiates mainly from the LE serrations andsurroundings, due to the small eddies broken up when the vortical flows pass through the LE serrations. Our results demonstrate that the biomimetic design of the LE serrations can facilitate the break-up of LE vortices passively and effectively without negatively impacting aerodynamic performance, which can be utilized as an effective device to improve the aeroacoustic performance of fan blades.

Creation of mortality risk calculator using a I-123 mIBG-based machine learning model: differential prediction of arrhythmic death and heart-failure death

Funding Acknowledgements

Type of funding sources: None.

Background

Although I-123 meta-iodobenzylguanidine (mIBG) has been applied to patients with chronic heart failure (CHF), a diagnostic tool for differential prediction of fatal arrhythmic events (ArE) and heart-failure death (HFD) has been pursued. 

Purpose

The aim of this study was to create a calculator of mortality risk for differentiating mode of cardiac death using a machine learning (ML) method, and to test the accuracy in a new cohort of patients with CHF.

Methods

A total of 529 patients with CHF was used as the training database for ML. The ArE group consisted of patients with arrhythmic death, sudden cardiac death and appropriate therapy by implantable cardioverter defibrillator. A heart-to-mediastinum ratio (H/M) standardized to the medium-energy collimator condition was calculated with a planar anterior mIBG scintigram. The best classifier models for predicting HFD and ArE were determined by four-fold cross validation. Input variables included age, sex, New York Heart Association (NYHA) functional class, left ventricular ejection fraction, ischemic etiology, mIBG H/M and washout rate, and b-type natriuretic peptide (BNP) or NT Pro BNP, estimated glomerular filtration rate, hemoglobin, and complications such as diabetes and hypertension. After creating the ML-based model, the constructed classifier functions for ArE, HFD, and survival were exported for subsequent use. A new cohort of patients (n = 312, age 67 ± 13 years, 2015 or later) was used to test the ML-based model.

Results

The training database included 141 events (27%) with ArE (7%) and HFD (20%). Receiver-operating characteristic analysis by four-fold validation showed area under the curve value of 0.90 for HFD and 0.73 for ArE. Among various ML methods, the logistic regression method demonstrated the most stable calculation of the probability of ArE followed by random forest and gradient boosted tree methods. Therefore, the logistic-regression method was used for calculating both HFD and ArE probabilities. In the test cohort, patients with a high HFD probability >8% resulted in 6.3-fold higher HFD than those with low probability (≤ 8%). Patients with high ArE probability >8% showed 2.5-fold higher ArE than those with low probability (≤ 8%).

Conclusion

The ML-based mortality risk calculator could be used for stratifying patients at high and low risks, which might be useful for estimating appropriate treatment strategy.

Flexible Flaps Inspired by Avian Feathers Can Enhance Aerodynamic Robustness in low Reynolds Number Airfoils

Unlike rigid rotors of drones, bird wings are composed of flexible feathers that can passively deform while achieving remarkable aerodynamic robustness in response to wind gusts. In this study, we conduct an experimental study on the effects of the flexible flaps inspired by the covert of bird wings on aerodynamic characteristics of fixed-wings in disturbances. Through force measurements and flow visualization in a low-speed wind tunnel, it is found that the flexible flaps can suppress the large-scale vortex shedding and hence reduce the fluctuations of aerodynamic forces in a disturbed flow behind an oscillating plate. Our results demonstrate that the stiffness of the flaps strongly affects the aerodynamic performance, and the force fluctuations are observed to be reduced when the deformation synchronizes with the strong vortex generation. The results point out that the simple attachment of the flexible flaps on the upper surface of the wing is an effective method, providing a novel biomimetic design to improve the aerodynamic robustness of small-scale drones with fixed-wings operating in unpredictable aerial environments.

Flexibility Effects of a Flapping Mechanism Inspired by Insect Musculoskeletal System on Flight Performance

Flying animals such as insects display great flight performances with high stability and maneuverability even under unpredictable disturbances in natural and man-made environments. Unlike man-made mechanical systems like a drone, insects can achieve various flapping motions through their flexible musculoskeletal systems. However, it remains poorly understood whether flexibility affects flight performances or not. Here, we conducted an experimental study on the effects of the flexibility associated with the flapping mechanisms on aerodynamic performance with a flexible flapping mechanism (FFM) inspired by the flexible musculoskeletal system of insects. Based on wing kinematic and force measurements, we found an appropriate combination of the flexible components could improve the aerodynamic efficiency by increasing the wingbeat amplitude. Results of the wind tunnel experiments suggested that, through some passive adjustment of the wing kinematics in concert with the flexible mechanism, the disturbance-induced effects could be suppressed. Therefore, the flight stability under the disturbances is improved. While the FFM with the most rigid spring was least efficient in the static experiments, the model was most robust against the wind within the range of the study. Our results, particularly regarding the trade-off between the efficiency and the robustness, point out the importance of the passive response of the flapping mechanisms, which may provide a functional biomimetic design for the flapping micro air vehicles (MAVs) capable of achieving high efficiency and stability.

Intermittent control strategy can enhance stabilization robustness in bumblebee hovering

Active flight control plays a crucial role in stabilizing the body posture of insects to stay aloft under a complex natural environment. Insects can achieve a closed-loop flight control by integrating the external mechanical system and the internal working system through manipulating wing kinematics according to feedback information from multiple sensors. While studies of proportional derivative/proportional integral derivative-based algorithms are the main subject to explore the continuous flight control mechanisms associated with insect flights, it is normally observed that insects achieve an intermittent spike firing in steering muscles to manipulate wings in flight control discontinuously. Here we proposed a novel intermittent control strategy for a 3 degree of freedom (DoF) pitch-control and explored its stabilization robustness in bumblebee hovering. An integrated computational model was established and validated, which comprises an insect-inspired dynamic flight simulator and a novel discrete feedback controller as well as a simplified free-flight dynamic model. We found that the intermittent control model can achieve an angular-dominant flight control, whereas the continuous control model corresponds to an angular-velocity-dominant one. Given the biological constraints in sensorimotor neurobiology and musculoskeletal mechanics, the intermittent control strategy was examined capable of enhancing the stabilization robustness in terms of sensory latency, stroke derivation, spike interval, and damping strength. Our results indicate that the intermittent control strategy is likely a sophisticated flight control mechanism in insect flights while providing a bioinspired flight-control design for insect size flapping-wing micro air vehicles.

Premature acute coronary syndrome patients do not have a better prognosis for their age than mature ACS patients by propensity score match analysis

Background

Acute coronary syndrome (ACS) is the most important cardiovascular (CV) disease with a prevalence that increases with age. There is no data which compared the prognosis with premature ACS and mature ACS using propensity score matched analysis

Purpose

The purpose of this study was to compare the prognosis of premature ACS patients and mature ACS patients using propensity score matched analysis.

Methods

We analyzed of 4249 ACS patients (69.1±12.6, male 77%) including 773 premature ACS patients (50.1±6.8, male 78%) and 3476 mature ACS (73.3±9.3, male 77%) from January 2013 to December 2018, using data from Mie ACS Registry, a prospective and multicenter registry in Japan.

Premature onset of ACS was defined as younger than 65 years old in male and 55 years old in female.

Primary end point was as major adverse cardiac event (MACE) including cardiovascular death, non-fetal myocardial infarction, heart failure requiring admission and unstable angina.

Results

During median follow duration of 742 days ranging from409 to 828 days, 502 MACE were occurred. Premature ACS patients were younger and showed higher body mass index compared to mature ACS patients (50.1±6.8 vs 73.3±9.3 y.o., 25.5 vs 23.0, P<0.001, respectively). However, premature ACS patients were more likely to be associated with ST elevation myocardial infarction, dyslipidemia, family history of coronary artery disease (CAD) and lower Killip classification compared to mature ACS patients (P<0.01, respectively). Common CAD risk factors such as hypertension, diabetes mellitus and past history of CAD were less associated with premature ACS patients compared to mature ACS patients (P<0.01, respectively). Unadjusted Kaplan-Meier survival curves demonstrated the favorable prognosis in premature ACS patients compared to mature ACS patients with hazard ratio of 0.57 (95% CI 0.45–0.71, P<0.001, see Figure 1A). We compared a 1:1 propensity score-matched cohort of 1208 patients with or without premature onset of ACS adjusting the several factors mentioned above (n=604, respectively). Age could not be introduced as a factor of propensity score match when comparing premature and mature ACS patients. After propensity score-match, premature ACS patients is about 18 years younger than mature ACS patients (50.7±6.5 vs 68.5±8.2 y.o., P<0.001). The average age of premature ACS was younger than that of mature ACS, but MACE by Kaplan-Meier survival analysis for premature ACS patients was equivalent to mature ACS patients (P=0.77, see Figure 1B).

Conclusion

Premature ACS patients are required very careful management because they might have factors with unfavorable prognosis, such as lifestyle habit and genetics, that may be beyond age.

Figure 1

Funding Acknowledgement

Type of funding source: None

Evaluation of temporal changes in longitudinal strain distribution during the systolic period to determine left ventricular activation sequence: a study using 2D speckle-tracking echocardiography

Background

Evaluation of two-dimensional (2D) speckle-tracking longitudinal strain (LS) is useful for assessing global and regional left ventricular (LV) dysfunction.

Purpose

The purpose of this study was to test the hypothesis that temporal changes in regional 2D-LS distribution, (i.e., changes in area and intensity of the negative strain), during the systolic period may reflect the LV activation sequence.

Methods

We studied 52 patients with an ejection fraction <35% who were classified into four groups: complete left bundle branch block (LBBB, QRS 162±17 ms, n=17); right ventricular pacing from inferior septum (RVP, QRS 180±29 ms, n=16); left VP from lateral branch of the coronary sinus (LVP, QRS 182±21 ms, n=9); and no conduction block (Narrow QRS, QRS 100±9 ms, n=19). Longitudinal strain was evaluated in three standard apical views, and then bulls-eye distribution maps were constructed every 50 ms from the QRS onset to aortic valve closing (AVC) and at the time of the end of QRS. Segments indicating negative strain at the end of QRS were regarded as an early contraction site. Segments with intensifying negativity of strain as it got closer to the AVC were regarded as a late contraction site.

Results

In patients with LBBB, negative strain appeared initially in the septum region. Then, the contracted area enlarged including the apical region, and the basal lateral region contracted late. On the other hand, Narrow QRS showed a few regional differences in strain at the end of QRS (standard deviation in 17-segments: Narrow QRS 1.3±0.4%*, LBBB 3.3±1.1%, RVP 3.2±1.0%, LVP 3.3±1.1%, *p<0.001), and contracted homogeneously during the systolic period. RVP and LVP showed negative strain at the end of QRS in septum and lateral regions respectively, with the contracted area becoming enlarged towards the opposite regions of the early contracted regions.

Conclusion

The 2D-LS distribution during the systolic period reflects the LV contraction process in patients with an altered ventricular activation sequence, and may have potential for identifying the regions of early activation site and subsequent activation propagation.

Funding Acknowledgement

Type of funding source: None

Aerodynamic imaging by mosquitoes inspires a surface detector for autonomous flying vehicles

Some flying animals use active sensing to perceive and avoid obstacles. Nocturnal mosquitoes exhibit a behavioral response to divert away from surfaces when vision is unavailable, indicating a short-range, mechanosensory collision-avoidance mechanism. We suggest that this behavior is mediated by perceiving modulations of their self-induced airflow patterns as they enter a ground or wall effect. We used computational fluid dynamics simulations of low-altitude and near-wall flights based on in vivo high-speed kinematic measurements to quantify changes in the self-generated pressure and velocity cues at the sensitive mechanosensory antennae. We validated the principle that encoding aerodynamic information can enable collision avoidance by developing a quadcopter with a sensory system inspired by the mosquito. Such low-power sensing systems have major potential for future use in safer rotorcraft control systems.

P37 Long-term outcomes of patients at risks for Fontan operation: role of temporary fenestration

Purpose

Whereas fenestration at Fontan operation was reported to be effective for smooth initiation to Fontan circulation, subsequently developed aortopulmonary collateral arteries under the presence of remaining hypoxia were a matter of concern.So as our institutional policy, it is closed as much and early as possible (temporary fenestration). This study aimed to reveal long-term outcomes for patients at riskswho underwent Fontan operation with temporary fenestration.

Methods

Of 107 patients undergoing Fontan operation from 1995 to 2004, 79 patients (73.8%) were free from any risks (NR group) and 28 patients (26.2%) had risks for Fontan operation (R group). Hypoplastic left heart syndrome, heterotaxy syndrome with obstructive total anomalous of pulmonary venous connection, and individual cases with high preoperative pulmonary artery pressure (PAP), systemic ventricular end diastolic pressure (SVEDP) or low ejection fraction (SVEF) were defined as a risk for Fontan completion.Age at Fontan operation was older in R group (6.6 vs 2.3years-old, p = 0.0004). Preoperative PAP (12.8 vs 11.3mmHg, p = 0.03) and SVEDP (8.8 vs 7.1mmHg, p = 0.02) were higher and SVEF (53.7 vs 60.0%, p = 0.002) was lower in R group. Pulmonary vascular resistance (PVR) was not different. Fenestration was created in all patients in R group, then it was closed at the mean duration of 2.9 years after Fontan operation.

Results

Freedom from death or protein-losing enteropathy rate at 5, 10, and 15 years after Fontan operation were 97, 96, and 93% in NR group and 96, 93, and 86% in R group (log-rank: p = 0.20). Fifty-one patients (64.6%) in NR group and 17 patients (60.7%) in R group underwent serial catheter examinations at 5, 10, and 15 years after Fontan operation and exercise capacity testing at 15 years after Fontan operation (Figure). In R group, arterial oxygen saturation was lower and PVR was higher even after close of fenestration (Figure). In addition, 12 patients (71%) in R group developed significant veno-venous collaterals, which were defined by more than 3mm in diameter of collateral veins or a condition where pulmonary veins were contrasted in venography. On the contrary, cardiac index (CI), SVEDP, and PAP were not different and no significant difference on peak oxygen uptake and anaerobic threshold were observed between in 2 groups. 

Conclusions

Although the mild cyanosis remained due to the development of veno-venous collaterals after the closure of temporary fenestration, CI, SVEDP and PAP well maintained in patients at risk for Fontan operation. These results might to lead acceptable life prognosis and freedom fromprotein-losing enteropathy rate for patients at risk for Fontan operation.

Abstract P37 Figure

Development of Mixed Flow Fans with Bio-Inspired Grooves

Mixed flow fan is a kind of widely used turbomachine, which has faced problems of further performance improvement in traditional design methods in recent decades. Inspired by the microgrooves such as riblets and denticles on bird feathers and shark skins, we here propose biomimetic designs of various blades with the bio-inspired grooves, aiming at the improvement of the aeroacoustic performance. Based on a systematic study with computational fluid dynamic analyses, we found that these designs had the potential in noise suppression even with macroscopic grooves. Our best design can suppress turbulence kinetic energy by approximately 38% at the blade leading edge with aerodynamic efficiency loss of only 0.3 percentage points. This improvement is achieved by passive flow control. The vortical structures are changed in a favorable way at the leading edge due to the grooves. We believe that these biomimetic designs could provide a promising future of enhancing the performance of mixed flow fans by making grooves of ideal flow passages on the suction faces of blades in accord with the theory of pump design.

P713Short term treatment of a low dose erythropoietin improves vascular function in a rat model of insulin resistance

Background/Introduction

Erythropoietin (EPO) exerts haematopoiesis-independent cardiovascular and renal protective effects by binding to EPO receptors expressed in hearts, arteries, and kidneys. We have reported that EPO inhibits vascular and renal injury in rat models of hypertension and type 1 diabetes. Recent studies report that EPO improves glucose tolerance in insulin resistant animals.

Purpose

This study investigated whether EPO would inhibit vascular and renal dysfunction in the setting of insulin resistance.

Methods

Rats were treated with sucrose (12% in drinking water) for 10 weeks to induce insulin resistance. EPO (3 times/week, s.c) was administered at the dose of 150U/kg for 10 weeks from the beginning (group A) or at the dose of 75U/kg for the last 4 weeks (group B) of sucrose treatment. Blood pressure was measured every second week by the tail-cuff method. HOMA-IR, haematocrit, and urinary protein excretion were measured. Using isolated aortas, acetylcholine-induced vasorelaxation under phenylephrine-induced pre-contraction was examined. Aortic sections were stained with haematoxylin-eosin.

Results

Both groups A and B showed higher haematocrit levels compared with the control and sucrose alone-treated groups. Sucrose treatment increased HOMA-IR (7.7±2.0 vs. 24±4.5, p<0.05), which was attenuated in groups A (3.6±0.9) and B (9.7±4.0). EPO treatment (150U/kg) had no effects on blood pressure for the first 4 weeks but caused time-dependent increases in blood pressure from the 6th week. Increased proteinuria and impaired aortic vasorelaxation in sucrose-treated rats were exacerbated by EPO (150U/kg) maybe because of hypertension (Control 122±2mmHg, Sucrose 125±2mmHg, group A 148±5mmHg), one of the major side effects of EPO. According to these results, we treated a half dose of EPO only for the last 4 weeks (group B). A lower dose of EPO treatment for a shorter period did not increase proteinuria (Control 15±2mg/day, Sucrose 25±3mg/day, group B 24±3mg/day) despite a mild increase in blood pressure (132±2mmHg). Impaired endothelium-dependent vasodilation and aortic thickening in the aorta of sucrose alone-treated rats were attenuated by lower and shorter EPO treatment (group B).

Conclusions

EPO inhibited insulin resistance and vascular injury in sucrose-induced insulin resistant rats. Further investigation into the mechanisms of tissue protective effects of EPO, especially focusing on the effects on insulin signalling in not only hepatic and muscle cell but also vascular and renal cells, will be needed.

P6275Role of autophagy in imatinib-induced cardiotoxicity

Background

Cardiotoxicity is one of the severe adverse effects of chemotherapeutic agents. Imatinib, a therapeutic agent for chronic myelogenous leukemia, has been reported to induce cardiotoxicity. Autophagy is an intracellular bulk protein and organelle degradation process, but it is unclear whether autophagy functions as pro-death or pro-survival program during disease conditions. We examined whether imatinib induces myocyte autophagy and the role of autophagy in imatinib-induced cardiotoxicity in in vitro and in vivo experiments.

Methods

In in vitro experiments, neonatal rat cardiac myocytes were treated with imatinib (1, 5, 10 μM; 1–6 hrs). Inhibition of autophagy was performed using 3-methyl-adenine (3MA), an autophagic inhibitor, and transfection with Atg5-targeted siRNA. Myocyte apoptosis was detected by morphological change in nuclei and caspase 3 activity. Mitochondria-derived reactive oxygen species production was detected using MitoSOX and mitochondrial membrane potential was assessed by TMRM staining. Expressions of cytochrome c in mitochondria and cytosole were examined by Werstern blotting. Myocyte autophagy was assessed by monodansylcadaverine staining and microtubule-associated protein light chain (LC) 3-II expression. In in vivo experiments, C57BL6 mice were treated with imatinib (50 and 200 mg/kg/day) for 5 weeks in the presence or absence of 3MA. Cardiac function was examined by echocardiography. In cardiac tissue, apoptotic myocytes were examined by TUNEL assay and autophagy was examined by LC3-II expression.

Results

In in vitro experiments, imatinib increased apoptotic nuclei and caspase 3 activity, in a dose-dependent manner. Consequently, imatinib augmented production of mitochondria-derived reactive oxygen species, loss of mitochondrial membrane potential, and the release of cytochrome c from mitochondria to cytosole, suggesting that imatinib induced mitochondrial-apoptotic pathway. On the other hand, imatinib significantly increased monodansylcadaverine stained dots and LC3-II expression, suggesting that imatinib increased autophagy. 3MA and Atg5 siRNA augmented imatinib-induced apoptosis by 60% and 30%, respectively. In in vivo experiments, imatinib (200 mg) exhibited the dilatation of left ventricle by 15% and the depression of left ventricular fractional shortening by 23%. Ratio of apoptotic myocytes was significantly increased and LC3-II expression in cardiac tissue was enhanced by imatinib in a dose-dependent fashion. Co-treatment with 3MA and imatinib further impaired imatinib-induced myocyte apoptosis by 3 fold and LV dysfunction by 20%.

Conclusion

These results indicate that imatinib induced myocyte apoptosis, leading to cardiac dysfunction. Imatinib enhanced myocyte autophagy as a consequence of apoptosis and autophagy was a beneficial phenomenon in this condition.

P1603Nicorandil suppresses ischemia-induced cardiac interstitial norepinephrine enhancement and ventricular arrhythmia in hypertrophic hearts

Background

Myocardial infarction (MI) is a major cause of death in western countries and Japan, and hypertension is a major risk factor of MI. In hypertensive heart, acute myocardial infarction often leads to lethal ventricular arrhythmia. Nicorandil, an ATP sensitive potassium channel (KATP) opener, is usually used in the treatment of acute myocardial infarction. The effects of nicorandil on ischemic myocyte are fully defined. On the other hand, KATP in neuroterminals is known to regulate norepinephrine release, but the effect of nicorandil on ischemic norepinephrine release in cardiac tissue has remained unexplored.

Purpose

We examined whether nicorandil suppressed norepinephrine release via neuronal KATP and ventricular arrhythmia during acute ischemia in pressure overload-induced hypertrophic hearts.

Methods

SD Rats were divided into two groups; abdominal aortic constriction (AAC) group and sham-operated (Sham) group. Four weeks after constriction, cardiac geometry and function were examined using echocardiography. Then, myocardial ischemia was induced by the left anterior descending artery occlusion for 100 minutes in the presence or absence of intravenous infusion of nicorandil. Cardiac interstitial norepinephrine concentration in ischemic region was measured using the microdialysis method and concentration of cyclic AMP, a second messenger of norepinephrine, in cardiac tissue was measured by ELISA. Ventricular arrhythmias were monitered by ECG during whole ischemic period.

Results

Four weeks after constriction, remarkable left ventricular wall thickening was observed in AAC group. Before ischemia, ventricular arrhythmia was not found in both groups. Number of ventricular arrhythmia, including ventricular tachycardia and ventricular fibrillation, was increased in early ischemic period (- 40 min) in both groups, and was grater in AAC group. Before ischemia, interstitial norepinephrine concentration in cardiac tissue was higher level in AAC group than in Sham group. Ischemia obviously increased norepinephrine concentration in both groups time dependently and AAC further increased norepinephrine than Sham group. Concentration of cyclic AMP in cardiac tissue was raised in early ischemic period (- 40 min) and then gradually decreased. Nicorandil significantly suppressed the number of ventricular arrhythmias, and abolished the ventricular tachycardia and fibrillation without hemodynamic alterations. Nicorandil also attenuated norepinephrine and cAMP enhancement in acute ischemic period in both groups.

Conclusion

Ischemia-induced ventricular arrhythmia was more frequent and severe in hypertrophic hearts and interstitial norepinephrine enhancement may play a role in this ischemic arrhythmia. Nicorandil suppressed ischemia-induced interstitial norepinephrine release by neuronal KATP opening, which attenuated ventricular arrhythmias in normal and hypertrophic hearts.

Longitudinal Findings of MRI and PET in West Syndrome with Subtle Focal Cortical Dysplasia

BACKGROUND AND PURPOSE

Despite the development of neuroimaging, identification of focal cortical dysplasia remains challenging. The purpose of this study was to show the longitudinal changes of MR imaging and FDG-PET in patients with West syndrome and subtle focal cortical dysplasia.

MATERIALS AND METHODS

Among 52 consecutive patients with West syndrome, 4 were diagnosed with subtle focal cortical dysplasia on 3T MR imaging. MR imaging and PET findings were evaluated longitudinally at onset and at 12 and 24 months of age.

RESULTS

At the onset of West syndrome, MR imaging demonstrated focal signal abnormalities of the subcortical white matter in 2 patients. In the other 2 patients, focal subcortical high-intensity signals became visible on follow-up T2WI as myelination progressed. PET at onset showed focal cortical hypometabolism in 3 patients, with 1 of these patients also having focal hypermetabolism and 1 having normal findings. On PET at 24 months, hypometabolism persisted in 2 patients and disappeared in 1, and hypermetabolism disappeared in 1. In 1 patient with normal MR imaging and PET findings at onset, focal hyperintensity and hypometabolism first appeared at 24 months of age. The findings on MR imaging and PET in these patients evolved differently with brain maturation and the clinical course.

CONCLUSIONS

Subtle focal cortical dysplasia can be undetectable on MR imaging at the onset of West syndrome and is not always accompanied by hypometabolism or hypermetabolism on PET. Longitudinal MR imaging and PET studies may be useful for detecting such lesions. Even in West syndrome with a congenital structural abnormality, PET findings evolve differently with brain maturation and the clinical condition.

Development of Bio-Inspired Low-Noise Propeller for a Drone

Multicopter-type unmanned aerial vehicles, called drones, have been attracting wide attention because of their immense potential for use in various missions such as surveillance, reconnaissance, and delivery service. For the application of drones, however, their noise will be a serious issue especially when operating in urban areas, and to our knowledge, it has not been resolved yet. In this study, inspired by the unique wing structures of insects and birds, we have developed new low-noise-type propellers for drones. The various bio-inspired attachments of drones such as the serrations at the leading edge, velvet-like surface, and fringes at the trailing edge were tested, and their acoustic and aerodynamic performances were evaluated experimentally and numerically. Our results indicate that an attachment at the trailing edge can suppress the noise level while maintaining the aerodynamic efficiency of the proposed propeller close to that of the basic propeller.

Forewings match the formation of leading-edge vortices and dominate aerodynamic force production in revolving insect wings

In many flying insects, forewings and hindwings are coupled mechanically to achieve flapping flight synchronously while being driven by action of the forewings. How the forewings and hindwings as well as their morphologies contribute to aerodynamic force production and flight control remains unclear. Here we address the point that the forewings can produce most of the aerodynamic forces even with the hindwings removed through a computational fluid dynamic study of three revolving insect wing models, which are identical to the wing morphologies and Reynolds numbers of hawkmoth (Manduca sexta), bumblebee (Bombus ignitus) and fruitfly (Drosophila melanogaster). We find that the forewing morphologies match the formation of leading-edge vortices (LEV) and are responsible for generating sufficient lift forces at the mean angles of attack and the Reynolds numbers where the three representative insects fly. The LEV formation and pressure loading keep almost unchanged with the hindwing removed, and even lead to some improvement in power factor and aerodynamic efficiency. Moreover, our results indicate that the size and strength of the LEVs can be well quantified with introduction of a conical LEV angle, which varies remarkably with angles of attack and Reynolds numbers but within the forewing region while showing less sensitivity to the wing morphologies. This implies that the forewing morphology very likely plays a dominant role in achieving low-Reynolds number aerodynamic performance in natural flyers as well as in revolving and/or flapping micro air vehicles.

Flight of the dragonflies and damselflies

This work is a synthesis of our current understanding of the mechanics, aerodynamics and visually mediated control of dragonfly and damselfly flight, with the addition of new experimental and computational data in several key areas. These are: the diversity of dragonfly wing morphologies, the aerodynamics of gliding flight, force generation in flapping flight, aerodynamic efficiency, comparative flight performance and pursuit strategies during predatory and territorial flights. New data are set in context by brief reviews covering anatomy at several scales, insect aerodynamics, neuromechanics and behaviour. We achieve a new perspective by means of a diverse range of techniques, including laser-line mapping of wing topographies, computational fluid dynamics simulations of finely detailed wing geometries, quantitative imaging using particle image velocimetry of on-wing and wake flow patterns, classical aerodynamic theory, photography in the field, infrared motion capture and multi-camera optical tracking of free flight trajectories in laboratory environments. Our comprehensive approach enables a novel synthesis of datasets and subfields that integrates many aspects of flight from the neurobiology of the compound eye, through the aeromechanical interface with the surrounding fluid, to flight performance under cruising and higher-energy behavioural modes.

This article is part of the themed issue ‘Moving in a moving medium: new perspectives on flight’.

Quantifying the dynamic wing morphing of hovering hummingbird

Animal wings are lightweight and flexible; hence, during flapping flight their shapes change. It has been known that such dynamic wing morphing reduces aerodynamic cost in insects, but the consequences in vertebrate flyers, particularly birds, are not well understood. We have developed a method to reconstruct a three-dimensional wing model of a bird from the wing outline and the feather shafts (rachides). The morphological and kinematic parameters can be obtained using the wing model, and the numerical or mechanical simulations may also be carried out. To test the effectiveness of the method, we recorded the hovering flight of a hummingbird (Amazilia amazilia) using high-speed cameras and reconstructed the right wing. The wing shape varied substantially within a stroke cycle. Specifically, the maximum and minimum wing areas differed by 18%, presumably due to feather sliding; the wing was bent near the wrist joint, towards the upward direction and opposite to the stroke direction; positive upward camber and the 'washout' twist (monotonic decrease in the angle of incidence from the proximal to distal wing) were observed during both half-strokes; the spanwise distribution of the twist was uniform during downstroke, but an abrupt increase near the wrist joint was found during upstroke.

Owl-inspired leading-edge serrations play a crucial role in aerodynamic force production and sound suppression

Owls are widely known for silent flight, achieving remarkably low noise gliding and flapping flights owing to their unique wing morphologies, which are normally characterized by leading-edge serrations, trailing-edge fringes and velvet-like surfaces. How these morphological features affect aerodynamic force production and sound suppression or noise reduction, however, is still not well known. Here we address an integrated study of owl-inspired single feather wing models with and without leading-edge serrations by combining large-eddy simulations (LES) with particle-image velocimetry (PIV) and force measurements in a low-speed wind tunnel. With velocity and pressure spectra analysis, we demonstrate that leading-edge serrations can passively control the laminar-turbulent transition over the upper wing surface, i.e. the suction surface at all angles of attack (0°  <  AoA  <  20°), and hence play a crucial role in aerodynamic force and sound production. We find that there exists a tradeoff between force production and sound suppression: serrated leading-edges reduce aerodynamic performance at lower AoAs  <  15° compared to clean leading-edges but are capable of achieving both noise reduction and aerodynamic performance at higher AoAs  >  15° where owl wings often reach in flight. Our results indicate that the owl-inspired leading-edge serrations may be a useful device for aero-acoustic control in biomimetic rotor designs for wind turbines, aircrafts, multi-rotor drones as well as other fluid machinery.

Smart wing rotation and trailing-edge vortices enable high frequency mosquito flight

Mosquitoes exhibit unusual wing kinematics; their long, slender wings flap at remarkably high frequencies for their size (>800 Hz)and with lower stroke amplitudes than any other insect group. This shifts weight support away from the translation-dominated, aerodynamic mechanisms used by most insects, as well as by helicopters and aeroplanes, towards poorly understood rotational mechanisms that occur when pitching at the end of each half-stroke. Here we report free-flight mosquito wing kinematics, solve the full Navier-Stokes equations using computational fluid dynamics with overset grids, and validate our results with in vivo flow measurements. We show that, although mosquitoes use familiar separated flow patterns, much of the aerodynamic force that supports their weight is generated in a manner unlike any previously described for a flying animal. There are three key features: leading-edge vortices (a well-known mechanism that appears to be almost ubiquitous in insect flight), trailing-edge vortices caused by a form of wake capture at stroke reversal, and rotational drag. The two new elements are largely independent of the wing velocity, instead relying on rapid changes in the pitch angle (wing rotation) at the end of each half-stroke, and they are therefore relatively immune to the shallow flapping amplitude. Moreover, these mechanisms are particularly well suited to high aspect ratio mosquito wings.

Breeding phenology and winter activity predict subsequent breeding success in a trans-global migratory seabird

Inter-seasonal events are believed to connect and affect reproductive performance (RP) in animals. However, much remains unknown about such carry-over effects (COEs), in particular how behaviour patterns during highly mobile life-history stages, such as migration, affect RP. To address this question, we measured at-sea behaviour in a long-lived migratory seabird, the Manx shearwater (Puffinus puffinus) and obtained data for individual migration cycles over 5 years, by tracking with geolocator/immersion loggers, along with 6 years of RP data. We found that individual breeding and non-breeding phenology correlated with subsequent RP, with birds hyperactive during winter more likely to fail to reproduce. Furthermore, parental investment during one year influenced breeding success during the next, a COE reflecting the trade-off between current and future RP. Our results suggest that different life-history stages interact to influence RP in the next breeding season, so that behaviour patterns during winter may be important determinants of variation in subsequent fitness among individuals.

The complex aerodynamic footprint of desert locusts revealed by large-volume tomographic particle image velocimetry

Particle image velocimetry has been the preferred experimental technique with which to study the aerodynamics of animal flight for over a decade. In that time, hardware has become more accessible and the software has progressed from the acquisition of planes through the flow field to the reconstruction of small volumetric measurements. Until now, it has not been possible to capture large volumes that incorporate the full wavelength of the aerodynamic track left behind during a complete wingbeat cycle. Here, we use a unique apparatus to acquire the first instantaneous wake volume of a flying animal's entire wingbeat. We confirm the presence of wake deformation behind desert locusts and quantify the effect of that deformation on estimates of aerodynamic force and the efficiency of lift generation. We present previously undescribed vortex wake phenomena, including entrainment around the wing-tip vortices of a set of secondary vortices borne of Kelvin–Helmholtz instability in the shear layer behind the flapping wings.

A CFD-informed quasi-steady model of flapping wing aerodynamics

Aerodynamic performance and agility during flapping flight are determined by the combination of wing shape and kinematics. The degree of morphological and kinematic optimisation is unknown and depends upon a large parameter space. Aimed at providing an accurate and computationally inexpensive modelling tool for flapping-wing aerodynamics, we propose a novel CFD (computational fluid dynamics)-informed quasi-steady model (CIQSM), which assumes that the aerodynamic forces on a flapping wing can be decomposed into the quasi-steady forces and parameterised based on CFD results. Using least-squares fitting, we determine a set of proportional coefficients for the quasi-steady model relating wing kinematics to instantaneous aerodynamic force and torque; we calculate power with the product of quasi-steady torques and angular velocity. With the quasi-steady model fully and independently parameterised on the basis of high-fidelity CFD modelling, it is capable of predicting flapping-wing aerodynamic forces and power more accurately than the conventional blade element model (BEM) does. The improvement can be attributed to, for instance, taking into account the effects of the induced downwash and the wing tip vortex on the force generation and power consumption. Our model is validated by comparing the aerodynamics of a CFD model and the present quasi-steady model using the example case of a hovering hawkmoth. It demonstrates that the CIQSM outperforms the conventional BEM while remaining computationally cheap, and hence can be an effective tool for revealing the mechanisms of optimization and control of kinematics and morphology in flapping-wing flight for both bio-flyers and unmanned air systems.

Switching to an L/N-type calcium channel blocker shows renoprotective effects in patients with chronic kidney disease: the Kyoto Cilnidipine Study

OBJECTIVE

This open-label, randomized controlled trial investigated the effects of cilnidipine, an L/N-type calcium channel blocker (CCB), in patients with chronic kidney disease (CKD).

METHODS

Sixty patients with CKD and well-controlled hypertension being treated with a renin- angiotensin system (RAS) inhibitor and an L-type CCB (L-CCB) were randomly assigned either to switch from the L-CCB to cilnidipine after a 4-week observation period or to continue with L-CCB treatment. Blood pressure, heart rate and renal function were monitored for 12 months. Data were available for analysis from 50 patients: 24 from the cilnidipine group and 26 from the L-CCB group.

RESULTS

Blood pressure was well controlled in both groups. After 12 months, proteinuria and heart rate were significantly decreased in the cilnidipine group, but proteinuria increased and heart rate remained unchanged in the L-CCB group. There was a significant positive correlation between the percentage changes in proteinuria and heart rate.

CONCLUSIONS

Cilnidipine has antihypertensive effects equivalent to those of L-CCBs. In patients with CKD, proteinuria can be decreased by switching from an L-CCB to cilnidipine, thereby improving renal function.