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The proportional–integral–derivative (PID) controller remains widely used in industrial applications today due to its simplicity and ease of implementation. However, tuning the controller’s gains is crucial for achieving desired performance. This study compares the performance of PID controllers within a cascade control architecture designed for both position and attitude control of a quadcopter. Particle swarm optimisation (PSO), grey wolf optimisation (GWO), artificial bee colony (ABC), and differential evaluation (DE) methods are employed to optimally tune the PID parameters. A set of PID gains is determined offline by minimising various modified multi-objective functions based on different fitness measures: IAE, ISE, ITAE and ITSE. These measures are adapted as fitness functions for position and attitude control. A simulation study is conducted to determine which fitness function yields the optimal PID gains, as evidenced by the lowest values of the objective functions. In these simulations, two different desired trajectories are designed, and the controllers are applied to ensure the quadcopter tracks these trajectories accurately. Additionally, to test the robustness of the flight control architecture and the finely tuned PID controllers against various environmental effects and parametric uncertainties, several case scenarios are also explored.
Aging is associated with increasing oxidative stress and declining antioxidant defences, making the body susceptible to various chronic conditions. Cruciferous vegetables contain glucoraphanin, which is metabolised into sulforaphane (SFN) in the gut(1). SFN activates a mechanism enhancing antioxidant defences that may contribute to a reduction in risk of age-related chronic diseases. Our hypothesis proposes that consuming cruciferous vegetables releases hepatic extracellular vesicles (EVs), which carry with a cargo of antioxidant proteins, into the systemic circulation(2) that are transported to ‘at risk’ tissues. We seek to characterise the antioxidant protein content of EVs from blood samples of healthy human volunteers from a prospective dietary intervention study trial called (GLOBE). The GLOBE study employs a randomised, single-blind, two-arm crossover design and involves 12 healthy male or female adults aged >55 years, at the time of enrolment, have a BMI in the range of 18.5-30 kg/m2, and have self-reported healthy (are not suffering from current illness like cancer, and gastrointestinal diseases including coeliac, Crohn’s, colitis, and irritable bowel syndrome) and not using any medications like antacids, laxatives and antibiotics which can interfere with normal digestive or metabolic processes. The dietary intervention consists of two commercially available treatments, one of which is a glucoraphanin-rich vegetable soup, while the other vegetable soup lacks glucoraphanin. Our initial focus lies in optimizing and standardizing a method for routinely characterizing EVs derived from healthy volunteers participating in dietary intervention studies. We specifically aim to extract EVs from a minimal plasma volume (2ml) using size exclusion chromatography (SEC). Subsequently, we intend to employ this method to analyse EVs obtained from 161 plasma samples collected from 12 participants during the GLOBE study for different time points like 0, 120, 240, 360, 480 min, 24 and 48 hr. Our goal is to gain insight into the role of EVs as part of the mechanisms by which consuming a moderate quantity of cruciferous vegetables may confer health benefits. Our research carries the potential to establish a standardised approach to the characterisation of EVs from healthy individuals which has several applications in nutrition research.
Eosinophilic meningitis or meningoencephalitis caused by Angiostrongylus cantonensis is endemic to the Pacific area of Asia, especially Taiwan, Thailand, and Japan. Although eosinophilia is an important clinical manifestation of A. cantonensis infection, the role of eosinophils in the progress of the infection remains to be elucidated. In this experiment, we show that A. cantonensis-induced eosinophilia and inflammation might lead to the induction of IAP/NF-κB, JAK/STAT1 and MEKK1/JNK signals. The phosphorylation levels of JAK and JNK, STAT1, IAP, NF-κB and MEKK1 protein products were significantly increased after 12 days or 15 days of A. cantonensis infection. However, no significant differences in MAPKs such as Raf, MEK-1, ERK1/2 and p38 expression were found between control and infected mice. The activation potency of JAK/STAT1, IAP/NF-κB and MEKK1/JNK started increasing on day 3, with significant induction on day 12 or day 15 after A. cantonensis infection. Consistent results were noted in the pathological observations, including eosinophilia, leukocyte infiltration, granulomatous reactions, and time responses in the brain tissues of infected mice. These data suggest that the development of brain injury by eosinophilia of A. cantonensis infection is associated with activation of JAK/STAT1 signals by cytokines, and/or activation of MEKK1/JNK by oxidant stress, and/or activation of NF-κB by increasing IAP expression.
In two-dimensional (2D) electron systems, the viscous flow is dominant when electron-electron collisions occur more frequently than the impurity or phonon scattering. In this work, a quantum hydrodynamic model, considering viscosity, is proposed to investigate the interaction of a charged particle moving above the two-dimensional viscous electron gas. The stopping power, perturbed electron gas density, and the spatial distribution of the velocity vector field have been theoretically analyzed and numerically calculated. The calculation results show that viscosity affects the spatial distribution and amplitude of the velocity field. The stopping power, which is an essential quantity for describing the interactions of ions with the 2D electron gas, is calculated, indicating that the incident particle will suffer less energy loss due to the weakening of the dynamic electron polarization and induced electric field in 2D electron gas with the viscosity. The values of the stopping power may be more accurate after considering the effect of viscosity. Our results may open up new possibilities to control the interaction of ions with 2D electron gas in the surface of metal or semiconductor heterostructure by variation of the viscosity.
Laser-induced damage threshold is the main limitation for fused silica optics in high-power laser applications. The existence of various defects near the surface is the key factor for the degradation of the threshold. In this work, the photoluminescence spectra at different regions of the damaged and recovered fused silica samples are recorded to analyze the correlation between photoluminescence of surface defects and laser-induced damage threshold. The experimental data concluded the inverse proportional correlation between fluorescence and laser-induced damage threshold value. The weak photoluminescence is the guarantee of the high laser-induced damage threshold, and then the higher local Si nanocluster concentration corresponds with the higher laser-induced damage threshold value for the fused silica optics after CO2 laser treatment. The investigation reveals that photoluminescence measurement can be employed to check the quality of pristine fused silica and evaluate the tendency of the laser-induced damage threshold value. The current results are helpful for understanding the evolution of interaction from CO2 laser treatment and fused silica optics and can provide the guide of process technology for the high quality of fused silica optics.
In this paper, a new approach to modeling and controlling the problems associated with a morphing unmanned aerial vehicle (UAV) is proposed. Within the scope of the study, a dataset was created by obtaining a wide range of aerodynamic parameters for the UAV with Ansys Fluent under variable conditions using the computational fluid dynamics approach. For this, a large dataset was created that considered 5 different angles of attack, 14 different swept angles, and 5 different velocities. While creating the dataset, the analyses were verified by considering studies that have been experimentally validated in the literature. Then, an artificial intelligence-based model was created using the dataset obtained. Metaheuristic algorithms such as the artificial bee colony algorithm, ant colony algorithm and genetic algorithms are used to increase the modeling success of the adaptive neuro-fuzzy inference system (ANFIS) approach. A novel modeling approach is proposed that constitutes a new decision support system for real-time flight. According to the results obtained, all the ANFIS models based on metaheuristic algorithms were more successful than the traditional approach, the multilinear regression model. The swept angle that meets the minimum lift needed by the UAV for different flight conditions was estimated with the help of the designed decision support system. Thus, the drag force is minimised while obtaining the required lift force. The performance of the UAV was compared with the nonmorphing configuration, and the results are presented in tables and graphs.
This paper presents the effects of wing kinematics on both normal forward flight and escape flight of a dragonfly. A Navier–Stokes-based numerical model has been adopted, and results have been substantiated by experimental data. The wing kinematics of tethered specimens and the prescribed wing morphology of a free-flying dragonfly were used in the simulation. To shed light on the interplay between kinematics and aerodynamics, a parametric study of the kinematics has been conducted. It is found that in escape flight, the dragonfly generates additional lift while the thrust reduces and the overall efficiency drops. Compared with normal forward flight, the escape mode produces larger lift force peaks. When the kinematics change to facilitate escape flight, the aerodynamic forces are affected by not only the flapping kinematics but, in the case of the hindwing, the varied wing–wing vortex interactions. The direction of the resultant force on each wing changes according to the change of the mean of pitching angle and stroke plane angle. We found that in the studied configurations, the varied phasing of the wings has a marginal effect on the aerodynamics of the dragonfly. It reduces lift and increases thrust, and this force modulation is slightly more efficient when the local angle of attack also changes. On the other hand, the change of angle of attack played a major role in leading-edge vortex formations and directing the resultant forces of the wings. The results can be useful in developing flight control strategies for micro air vehicle design.
Plasma vertical displacement control is essential for the stable operation of tokamak devices. The traditional plasma vertical displacement calculation method is not suitable for balancing speed and accuracy simultaneously, which is necessary for real-time feedback control. In this study, neural networks are used to rapidly detect vertical displacement recognition. Based on a fully connected neural network, the vertical displacement calculation model is trained and tested using magnetic data of approximately 2000 shots. To compare the effects of different inputs on vertical displacement calculation, different magnetic measurement diagnostic signals are used to train and test the model. Compared with a full magnetic measurement dataset, 39 magnetic measurement signals (38 magnetic probes and plasma current) show better accuracy with mean square error <0.0005. The model is tested using historical experimental data, and it demonstrates accurate vertical displacement calculation even in the case of a vertical displacement event. In general, neural network algorithm has great application potential in vertical displacement calculation.
In this paper, a pulsed spark discharge plasma actuator array is deployed to control laminar–turbulent transition in a Mach 3.0 flat-plate boundary layer, and the subtle flow structures are visualized by nanoparticle planar laser scattering (NPLS) technique. Results show that the onset location of turbulence can be brought upstream by plasma actuation, corresponding to forced boundary-layer transition. Hairpin vortex packets evolved from the thermal bulbs play a vital role in the breakdown of laminar flow. With the help of a machine learning tool, all the relevant structures induced by plasma actuation are extracted from NPLS images, and a conceptual model of the hairpin vortex generation is proposed, including three stages: production and lift-up of the high-vorticity region, formation of the $\varLambda$ vortex and evolution of the hairpin vortex.
Aeolianites and cemented foreshore deposits on South Africa's Cape south coast have the capacity to record and preserve events that transpired on them when they were composed of unconsolidated sand. Thirty-five Pleistocene elephant tracksites have been identified along this coastline. This abundance of sites along what was the margin of the vast Palaeo-Agulhas Plain allows for an appreciation of the forms that elephant tracks and traces can take in the context of the global proboscidean track record. They point to a significant regional elephant presence from Marine Isotope Stage (MIS) 11 (~400 ka) through MIS 5 (~130–80 ka) to MIS 3 (~35 ka) and also indicate repeated use of certain dune areas. They buttress Holocene and historical evidence that elephants made use of open areas in the region, and that the remaining “Knysna elephants” retreated into dense afrotemperate forest for protection in recent centuries. Analogies can be drawn between Pleistocene elephant tracks and Mesozoic dinosaur tracks, and some of the Cape south coast elephant tracks are among the largest Cenozoic (and hence, Quaternary) tracks ever to be described. A newly identified tracksite in this area may provide the first reported evidence of elephant trunk-drag impressions.
In order to know the characteristics of reducing the exhaust gas infrared signal of the lobed mixer according to the external air mixing ratio, an infrared signal and temperature distribution measurement using a micro-turbojet engine is performed. A certain amount of compressed air is supplied through an external duct mounted on the micro-turbojet engine exhaust to simulate bypass flow, which is mixed with high-temperature core air and ejected to the atmosphere. The exhaust nozzle used in the experiment is a lobed mixer with a lobe of sinusoidal shape and is designed to have a penetration of 0.2. Exhaust gas temperature and infrared signal are measured according to distance from nozzle outlet under conditions of bypass ratio of 0.5, 1.0 and 1.4. Infrared reduction rates are compared to data without compressed air supply. As a result of the experiment, as the bypass ratio increased, the infrared signal of the exhaust gas and the temperature decrease with bypass ratio increase, and in the case of a bypass ratio of 1.4, the effect of reducing the temperature is observed even at a long distance. In addition, we compared the results of previous studies of a simple cone shape without mixer with infrared reduction effect. The results show that the lobed mixer has a greater effect on reducing the temperature of the exhaust gas and reducing the infrared signal than the cone nozzle. The structure of the mixed jet flow is also studied through Schlieren visualisation and 3D temperature distribution.
In patients diagnosed with amnestic mild cognitive impairment (aMCI) cognitive functions are also affected in addition to memory. The aim of the present study was to characterize these cognitive impairments in detail.
Methods
So far 35 patients with aMCI and 26 matched controls were investigated using following subtests of the Cambridge Neuropsychological Test Automated Battery (CANTAB): Delayed Matching to Sample, Spatial Recognition Memory, Spatial Working Memory, Rapid Visual Processing, and Stockings of Cambridge. Additionally, we used Corsi Block Tapping from the Wechsler Memory Scale Revised to examine spatial working memory and spatial attention.
Results
The aMCI group performed significantly worse than the control group in Delayed Matching to Sample, Spatial Working Memory, Rapid Visual Processing, Stockings of Cambridge, and Corsi Block Tapping backwards.
Conclusions
In summary, patients with aMCI demonstrate reduced skills in visual memory, spatial planning, spatial working memory, and sustained attention compared to healthy subjects. Furthermore, this suggests that CANTAB may be a tool for diagnosis of the cognitive status of aMCI patients.
The extent of working memory (WM) impairment has rarely been studied in patients with amnestic mild cognitive impairment (aMCI). The aim of the present study was to evaluate the cortical activation in these patients compared to healthy controls while performing a visuo-spatial WM task.
Methods
Functional magnetic resonance imaging (fMRI) with a 3-Tesla head scanner (Allegra, Siemens) was used to investigate the neural correlates of WM in 25 aMCI subjects and 12 matched controls while performing a visual-spatial n-back task (2-back). Both groups were pretested to ensure that all participants were able to understand and perform the task.
Results
In comparison to the healthy subjects, a random-effects analysis revealed that patients with aMCI showed less cortical activation especially in the left superior parietal cortex and left inferior frontal cortex. These areas are known to be involved in the control of attention and visuo-spatial WM.
Conclusions
Our findings suggest that attenuated cortical activation during working memory tasks may provide an early marker for aMCI.
The issues of timing in antidepressant treatment are of great theoretical and practical relevance, even more so since recent meta-analyses yielded no evidence for a specific mode of action of antidepressants, which, according to the theory of delayed onset of action, is expected to emerge after 2 weeks of therapy. To address the issues of timing on a methodologically sound basis, future trials should adapt a ‘longitudinal’ rather than ‘cross-sectional’ design, standardized with respect to a washout period, baseline and first 2 week assessments. With this in mind, special attention should be paid to parameters which potentially enable the identification of placebo responders, true drug responders and patients at risk of non-improvement. Results and methods of the Zurich meta-analyses may serve as a starting point for further steps in this direction.
The onset of action of antidepressant drugs was investigated on the basis of two independent multicenter, double-blind efficacy studies comparing amitriptyline (n = 120), oxaprotiline (n = 120), imipramine (n = 506) and moclobemide (n = 580) with placebo (n = 189 + 191). The samples consisted of in- and outpatients diagnosed, according to Diagnostic and Statistical Manual (DSM)-III criteria, as suffering from major depressive disorder. Measures of efficacy criteria were the Hamilton Rating Scale for Depression (HAM-D), the Hamilton Rating Scale for Anxiety (HAM-A) and the Zung Self-Rating Depression scale. By using the Sustained Relative Improvement (SRI) criterion, onset of action was determined in each individual patient as that time point in the 30 day observation period at which a 20% baseline score reduction was achieved without subsequent deterioration. Analogously, a response to treatment was defined as a 50% baseline score reduction. As expected, highly significant differences between active drugs and placebo were found with respect to the total number of improvers and responders. Significant differences between treatment modalities surfaced in the percentage rate as well as the time distribution of premature withdrawals. Yet, unexpectedly, among improvers, the time spans to onset of improvement were found to be independent of treatment modality as indicated by virtually identical cumulative percentages of improvers throughout the whole observation period. The picture was essentially the same for the HAM-A and Zung assessments, except for a significant time lag between observer- and self-ratings. In particular, our analyses revealed no evidence for a delayed onset of action under various antidepressants with large biochemical and pharmacological differences in comparison to placebo. Moreover, the early onset of improvement was highly predictive of later outcome: on average, 70% of the patients showing improvement within the first 14 days became responders. Applying survival-analytical methods, we found that differences between active treatments and placebo emerged within the first 5 days and reached a point of maximum distinction around day 14. After this time point, differences between treatment modalities remained constant until the end of the observation period. According to our data, 20–25% of the patients were, on average, ‘true’ drug responders, thus suggesting that the therapeutic qualities of antidepressants do not lie in the suppression of symptoms, but rather are related to their ability to elicit and maintain certain conditions which allow recovery in a subgroup of patients who would otherwise remain non-responders.
In the present open prospective study the effects of quetiapine were investigated in two elderly patients with parkinsonism and psychosis. Treatment induced a marked antipsychotic effect that coincided with an improvement of general motor functioning. These findings support the idea that quetiapine may be preferentially of use in the elderly with parkinson’s disease and psychotic symptoms.