The effect of folding wingtips on the worst-case gust loads of a simplified aircraft model

In recent years, the development of lighter and more efficient transport aircraft has led to an increased focus on gust load alleviation. A recent strategy is based on the use of folding wingtip devices that increase the aspect ratio and therefore improve the aircraft performance. Moreover, numerical studies have suggested such a folding wingtip solution may incorporate spring devices in order to provide additional gust load alleviation ability in flight. It has been shown that wingtip mass, stiffness connection and hinge orientation are key parameters to avoid flutter and achieve load alleviation during gusts. The objective of this work is to show the effects of aeroelastic hinged wingtip on the problem of worst-case gust prediction and the parameterization and optimization of such a model for this particular problem, that is, worst-case gust load prediction. In this article, a simplified aeroelastic model of full symmetric aircraft with rigid movable wingtips is developed. The effects of hinge position, orientation and spring stiffness are considered in order to evaluate the performance of this technique for gust load alleviation. In addition, the longitudinal flight dynamics of a rigid aircraft with an elastic wing and folding wingtips is studied. Multi-objective optimizations are performed using a genetic algorithm to exploit the optimal combinations of the wingtip parameters that minimize the gust response for the whole flight envelope while keeping flutter speed within the safety margin. Two strategies to increase flutter speed based on the modification of the wingtip parameters are presented

Cardioprotective effects of deferoxamine in acute and subacute cardiotoxicities of doxorubicin: a randomized clinical trial

Background: Cardiotoxicity is a major concern following doxorubicin (DOX) use in the treatment of malignancies. We aimed to investigate whether deferoxamine (DFO) can prevent acute cardiotoxicity in children with cancer who were treated with DOX as part of their chemotherapy. Results: Sixty-two newly-diagnosed pediatric cancer patients aged 2–18 years with DOX as part of their treatment regimens were assigned to three groups: group 1 (no intervention, n = 21), group II (Deferoxamine (DFO) 10 times DOX dose, n = 20), and group III (DFO 50 mg/kg, n = 21). Patients in the intervention groups were pretreated with DFO 8-h intravenous infusion in each chemotherapy course during and after completion of DOX infusion. Conventional and tissue Doppler echocardiography, serum concentrations of human brain natriuretic peptide (BNP), and cardiac troponin I (cTnI) were checked after the last course of chemotherapy. Sixty patients were analyzed. The level of cTnI was < 0.01 in all patients. Serum BNP was significantly lower in group 3 compared to control subjects (P = 0.036). No significant differences were observed in the parameters of Doppler echocardiography. Significant lower values of tissue Doppler late diastolic velocity at the lateral annulus of the tricuspid valve were noticed in group 3 in comparison with controls. By using Pearson analysis, tissue Doppler systolic velocity of the septum showed a marginally significant negative correlation with DOX dose (P = 0.05, r = − 0.308). No adverse effect was reported in the intervention groups. Conclusions: High-dose DFO (50 mg/kg) may serve as a promising cardioprotective agent at least at the molecular level in cancer patients treated with DOX. Further multicenter trials with longer follow-ups are needed to investigate its protective role in delayed DOX-induced cardiac damage. Trial registration IRCT, IRCT2016080615666N5. Registered 6 September 2016

Engine Placement Effects on the Flutter of a Medium-Range Box-Wing Aircraft

This study investigated the effects of powered engines on the stability boundaries of a box-wing configuration. The governing equations were obtained using Hamilton's principle. The equivalent effects of engine's mass and thrust were simulated using a concentrated mass which was subjected to a follower force. The structural dynamics of the box wing were modeled using two cantilever beams which were attached to each other through two longitudinal and torsional springs at their tips. The aerodynamic loads applied on the wings were calculated using Wagner's unsteady aerodynamic model. The time-dependent and the parameter-dependent integral parts were eliminated using the multistep semianalytical method. To validate the developed aeroelastic model, the flutter speed and frequency of conventional wings and box wings were obtained, and very good agreement was observed. The analysis showed that the stability of the wing can be affected when the effects of engines are considered. Furthermore, the engine placement and thrust effects on the box-wing flutter speed and frequency were considered

TRAIL in oncology: From recombinant TRAIL to nano- and self-targeted TRAIL-based therapies

TNF-related apoptosis-inducing ligand (TRAIL) selectively induces the apoptosis pathway in tumor cells leading to tumor cell death. Because TRAIL induction can kill tumor cells, cancer researchers have developed many agents to target TRAIL and some of these agents have entered clinical trials in oncology. Unfortunately, these trials have failed for many reasons, including drug resistance, off-target toxicities, short half-life, and specifically in gene therapy due to the limited uptake of TRAIL genes by cancer cells. To address these drawbacks, translational researchers have utilized drug delivery platforms. Although, these platforms can improve TRAIL-based therapies, they are unable to sufficiently translate the full potential of TRAIL-targeting to clinically viable products. Herein, we first summarize the complex biology of TRAIL signaling, including TRAILs cross-talk with other signaling pathways and immune cells. Next, we focus on known resistant mechanisms to TRAIL-based therapies. Then, we discuss how nano-formulation has the potential to enhance the therapeutic efficacy of TRAIL protein. Finally, we specify strategies with the potential to overcome the challenges that cannot be addressed via nanotechnology alone, including the alternative methods of TRAIL-expressing circulating cells, tumor-targeting bacteria, viruses, and exosomes

The Comparison of Pulse Oximetry and Cardiac Catheterization in Managing the Treatment of Children with Congenital Heart Disease

Bachground & aim: Pulse oximetry and cardiac catheterization are concerned in the treatment of children with congenital heart disease. Diagnosis of arterial oxygen saturation in patients with congenital heart disease (CHD) can be used to assess and manage their effecacy. The purpose of this study was to compare pulse oximetry and cardiac catheterizations in treatment manage of children with congenital heart disease. Methods: In the present cross sectional study, 110 patients with cyanic and non syani heart disease were studied undergoing right and left heart catheterization by pulse oximetry of index finger and simultaneously, oxygen saturation was measured by cardiac catheterization. Data were analyzed with SPSS software by using Pearson correlation and linear regression. Results: A significant correlation was seen between arterial oxygen saturation measured by pulse oximetry and arterial oxygen saturation (p<0.0001) as well as heart rate, electrocardiogram and pulse oximetry (p<0.0001) respectively. Furthermore, the presence of cyanosis (p=0.001), digital clubbing of the fingers ((p=0.001), low oxygen saturation in the superior vena cava and right atrium (p=0.002) can reduce the accuracy of pulse oximetry for detection of arterial oxygen saturation. The mean right atrial pressure can effect on accuracy of pulse oximetry to detect heartbeat (p=0.034). Maximum sensitivity and specificity for detection of pulse oximetry oxygen saturation was 88 % and 88 heart rate per minute. Conclusion: Pulse oximetric is a useful tool for estimating the arterial oxygen saturation and heart rate in children with congenital heart disease (CHD) and is a non-invasive method in comparison with cardiac catheterization. Key words: Pulse oximeter, Congenital Heart Disease, Cardiac Catheterizatio