Search

It is a challenging task to affect suitably on the frequency response of a variable speed wind turbine (VSWT). The problem would be more crucial when the system is subjected to uncertainty in parameters as well as various external effects such as load changes and grid disturbances. Feedback linearization has already been applied to the VSWT, where two state variables experience instability. Hence, this paper presents a new methodology based on full-state feedback linearization in which by choosing an appropriate output, the closed-loop system is fully linearized, and the resulting linear system is stabilized by an optimal linear quadratic regulator (LQR). Since the parameters may be uncertain, the developed controller is augmented with an adaptive dynamic feedback such that all of the parameters are estimated while asymptotic stability is ensured by the Lyapunov method. Furthermore, robustness analysis is performed, and the effects of external disturbance are reduced by suitable selection of the gains. The analytical outcomes are verified through simulations, where these are compared with those of available work to show the improvement have been made by the suggested method.

The article discusses the challenges facing Iranian President Masoud Pezeshkian in forming an effective government. The regime's preference for ideological commitment over expertise has led to institutional decay and a lack of qualified managers. Pezeshkian had promised to replace incompetent managers with experienced technocrats, but the compromised selection process and the dominance of unelected entities make it unlikely that his government will be able to implement effective policies. The article also highlights the political tensions and ideological screening processes that further hinder the government's efficacy. Overall, the article suggests that Pezeshkian's government is likely to face institutional entanglements and paralysis, leading to popular resentment and limited engagement with the international community. [Extracted from the article]

This article discusses the implications of Masoud Pezeshkian's victory in Iran's presidential election. The experts interviewed in the article highlight the ethnic factors that contributed to Pezeshkian's win, as well as the low voter turnout in the first round of the election. They also discuss the challenges and limitations that Pezeshkian may face as president, including the influence of Ayatollah Ali Khamenei and the Islamic Revolutionary Guard Corps. The experts suggest that significant policy changes are unlikely and that Pezeshkian's government will likely adhere to established regime policies. Additionally, they note that Iran's pursuit of nuclear weapons is expected to continue regardless of the election outcome. [Extracted from the article]

chart tab

The article discusses the recent elections in Iran and highlights the declining democratic nature of the regime. It explains that past elections in Iran were relatively competitive, but the Guardian Council, appointed by the Supreme Leader, had the power to veto legislation and disqualify candidates, limiting the impact of these elections. Over time, elections became more manipulated and less competitive, with elected bodies becoming increasingly irrelevant. The article also notes that voter participation has declined, and the regime's efforts to misrepresent turnout have been unsuccessful. The upcoming elections are expected to have low turnout, and the regime will use tactics to increase participation. Overall, the article suggests that Iran's elections are losing their effectiveness in creating the illusion of public participation and coopting elites, and the regime is relying more on repression to maintain control. [Extracted from the article]

In the summer of 2009, the regime of Ayatollah Ali Khamene'i was rocked by demonstrations throughout the major cities of Iran as people from all walks of life protested the [...]

The brain-derived neurotrophic factor (BDNF) is critically involved in neuroplasticity, as well as the acquisition, consolidation, and retention of hippocampal- and amygdala-dependent learning. A common functional A[right arrow]G single nucleotide polymorphism (BDNFval66met) in the prodomain of the human BDNF gene is associated with abnormal intracellular trafficking and reduced activity-dependent BDNF release. We studied the effect of BDNFval66met in an aversive differential fear conditioning, and a delayed extinction paradigm in 57 healthy participants. Pictures of male faces were used as stimuli and fear learning was quantified by fear potentiated startle (FPS) and skin conductance responses (SCR). Aware BDNF met-carriers show a deficit in amygdala-dependent fear conditioning as indicated by an absence of FPS responses in the last acquisition block. This deficit was maintained in the first block of extinction. No genotype differences were found in conditioned SCR discrimination. These data provide evidence for the involvement of BDNF signaling in human amygdala-dependent learning. We suggest that the BDNF met-allele may have a protective effect for the development of affective pathologies that may be mediated via reduced synaptic plasticity induced by negative experience. Keywords: brain-derived neurotrophic factor, synaptic plasticity, learning, anxiety, fear-potentiated startle Supplemental materials: http://dx.doi.org/10.1037/a0018261.supp DOI: 10.1037/a0018261

AbstractThe recombinant human keratinocyte growth factor (rhKGF) is a highly aggregation-prone therapeutic protein. The high aggregation liability of rhKGF is manifested by loss of the monomeric state, and accumulation of the aggregated species even at moderate temperatures. Here, we analyzed the rhKGF for its vulnerability toward aggregation by detection of aggregation-prone regions (APRs) using several sequence-based computational tools including TANGO, ZipperDB, AGGRESCAN, Zyggregator, Camsol, PASTA, SALSA, WALTZ, SODA, Amylpred, AMYPDB, and structure-based tools including SolubiS, CamSol structurally corrected, Aggrescan3D and spatial aggregation propensity (SAP) algorithm. The sequence-based prediction of APRs in rhKGF indicated that they are mainly located at positions 10–30, 40–60, 61–66, 88–120, and 130–140. Mapping on the rhKGF structure revealed that most of these residues including F16-R25, I43, E45, R47-I56, F61, Y62, N66, L88-E91, E108-F110, A112, N114, T131, and H133-T140 are surface-exposed in the native state which can promote aggregation without major unfolding event, or the conformational change may occur in the oligomers. The other regions are buried in the native state and their contribution to non-native aggregation is mediated by a preceding unfolding event. The structure-based prediction of APRs using the SAP tool limited the number of identified APRs to the dynamically-exposed hydrophobic residues including V12, A50, V51, L88, I89, L90, I118, L135, and I139 mediating the native-state aggregation. Our analysis of APRs in rhKGF identified the regions determining the intrinsic aggregation propensity of the rhKGF which are the candidate positions for engineering the rhKGF to reduce its aggregation tendency.Communicated by Ramaswamy H. Sarma

The conventional approach for addressing bone defects and stubborn non-unions typically involves the use of autogenous bone grafts. Nevertheless, obtaining these grafts can be challenging, and the procedure can lead to significant morbidity. Three primary treatment strategies for managing bone defects and non-unions prove resistant to conventional treatments: synthetic bone graft substitutes (BGS), a combination of BGS with bioactive molecules, and the use of BGS in conjunction with stem cells. In the realm of synthetic BGS, a multitude of biomaterials have emerged for creating scaffolds in bone tissue engineering (TE). These materials encompass biometals like titanium, iron, magnesium, and zinc, as well as bioceramics such as hydroxyapatite (HA) and tricalcium phosphate (TCP). Bone TE scaffolds serve as temporary implants, fostering tissue ingrowth and the regeneration of new bone. They are meticulously designed to enhance bone healing by optimizing geometric, mechanical, and biological properties. These scaffolds undergo continual remodeling facilitated by bone cells like osteoblasts and osteoclasts. Through various signaling pathways, stem cells and bone cells work together to regulate bone regeneration when a portion of bone is damaged or deformed. By targeting signaling pathways, bone TE can improve bone defects through effective therapies. This review provided insights into the interplay between cells and the current state of bioceramics in the context of bone regeneration.

Most sour-gas processing facilities separate hydrogen sulfide ([H.sub.2]S) and carbon dioxide ([CO.sub.2]) from raw gas through chemical absorption using alkanolamines (or 'amines'). The prime alkanolamines are: monoethanolamine (MEA), diethanolamine (DEA), [...]

Hardware developers started experimenting with Scrum to accelerate their product development. However, it is not possible to implement Scrum in the same way as it was done for software systems, where the approach is already well established. One of the processes required in Scrum is the estimate of task efforts when creating a backlog for an Agile Sprint. This article presents a pilot validation experiment of a novel Agile framework for the development of hardware systems, including a parametric tool to estimate task effort in a more rigorous way than traditional confidence votes. This article presents the validation of electronic hardware design task estimation and overall project performance. The validation is performed through experimental work with teams of junior engineering students. The validation experiment showed an improvement from a minimum of eight to a maximum of eighteen percent when employing the presented tool during planning phases of the development.

This work presents a model of the process of conceptual design studies which use the concurrent engineering approach. Concurrent conceptual design is an integrated system development approach, to rapidly explore feasible design solutions by parallelizing the work of experts. This approach is characterized by a multidisciplinary team of experts collaborating in a co‐located manner. Albeit the conceptual design phase requires creative problem solving, teamwork requires coordination, and would profit from a shared understanding of the design process. Based on a survey among experts from 15 different organizations, and practice documented in literature, we propose a model of the underlying design process. This work extends our previous work on a coordination method for concurrent design and provides validation of the process model via case studies and expert interviews. The proposed process model is formalized in SysML diagrams. It can be used to help program coordinators and train engineers of different disciplines on the methodology of concurrent conceptual design, as well to serve as a baseline for implementing the methodology in new organizations.

Diabetic retinopathy (DR) is a common ophthalmic disease among diabetic patients. It is essential to diagnose DR in the early stages of treatment. Various imaging systems have been proposed to detect and visualize retina diseases. The fluorescein angiography (FA) imaging technique is now widely used as a gold standard technique to evaluate the clinical manifestations of DR. Optical coherence tomography (OCT) imaging is another technique that provides 3D information of the retinal structure. The FA and OCT images are captured in two different phases and field of views and image fusion of these modalities are of interest to clinicians. This paper proposes a hybrid registration framework based on the extraction and refinement of segmented major blood vessels of retinal images. The newly extracted features significantly improve the success rate of global registration results in the complex blood vessel network of retinal images. Afterward, intensity-based and deformable transformations are utilized to further compensate the motion magnitude between the FA and OCT images. Experimental results of 26 images of the various stages of DR patients indicate that this algorithm yields promising registration and fusion results for clinical routine.

In recent years, the engineering community realized the potential for additive manufacturing (AM) to be a game-changer in product development. Nevertheless, it is not yet possible to fully take advantage of this technology because it implies a different approach to engineering design. The dependencies of AM on related technologies, such as material modeling, design tools, computing, and process design represent a challenge for engineers. A comprehensive system engineering approach is needed to address the introduction of AM in new design projects. This article proposes a systems design approach to evaluate the use of AM in the development of new systems at the early stage of design. The methodology aims to provide a preliminary estimation of performance, cost, and time of parts manufactured using additive techniques. The article introduces a set of design drivers and criteria to standardize the design process and support the manufacturing technique decision-making process. The methodology is experimentally tested and validated by evaluating tradeoffs for two different case studies considering different engineering parameters. The analysis of the results shows a good consistency between framework predictions and experimental evidence, with an uncertainty level lower than 5%. The reliability of obtained results is discussed.

Background: Alyssum L. is a genus of herbaceous perennial or annual plants belonging to the Brassicaceae family. Little is known about biochemical properties of Alyssum species, specially endemics to Iran. In particular, the species were A. homolocarpum (Fisch. & C.A.Mey.) Boiss., A. lepidotum Boiss., A. maritimum (L.) Lam. (now syn. of Lobularia maritima (L.) Desv.) and A. simplex Rudolph. and eight accessions were studied. These diverse species accessions were collected in six different areas. Materials and Methods: In this work, the Total Phenolic Content (TPC), the Total Flavonoid Content (TFD), the Total Flavonol Content (TFL), the Carotenoid content (Car) and the Anthocyanin content (Ant) of the leaf methanolic extracts of four Alyssum L. species collected in Iran, were assessed. The antioxidant activity assay for every extract obtained from the eight accessions was also carried out according to three distinct methodologies including three different methods including: DPPH, Beta carotene/ linoleic acid and phosphomolibdate assays. Results: The highest TPC, TFD and TFL values were separately observed in two different accessions of A. lepidotum whereas the highest carotenoid content was observed in one accession of A. homolocarpum and the highest anthocyanin content was observed in A. maritimum. Different results were observed for different methodolies for antioxidant evaluations methods and some of them were found to have values, expressed in mg/mL, much lower with respect to the control. The least DPPH activity and the highest total antioxidant activity with phosphomolybdate assay was found in A. lepidotum. Conclusion: The preliminary phytochemical screening and the evaluation of their antioxidant activities were reported here for the first time for Iranian Alyssum species. The findings eventually recommends, the use of those accessions in the ethnopharmacological and nutraceutical fields.

In this paper, we provide an analytical investigation of the entanglement dynamics of moving qubits dissipating into a common and (in general) non-Markovian environment for both weak and strong coupling regimes. We first consider the case of two moving qubits in a common environment and then generalize it to an arbitrary number of moving qubits. Our results show that when the system evolves from an initial entangled state, the amount of initial entanglement decreases and finally disappears after a finite interval of time due to the environmental effects. Moreover, we observe that the movement of qubits has a constructive role in the protection of the initial entanglement. In a sense, in this case, we observe a Zeno-like effect due to the velocity of qubits. On the other hand, we demonstrate how a stationary state of entanglement may be achieved when we consider the case in which at least one of the moving qubits is initially in the ground state. Surprisingly, we observe that when we extend the number of moving qubits with the same velocity, the stationary state of the qubits does not depend on the velocity of qubits as well as on the environmental properties. This means that, in this condition, the stationary state of entanglement depends only on the number of moving qubits.

This paper proposes the concept of experiential systems engineering (ESE) as a hands-on education approach for teaching systems engineering (SE) tools and methods in postgraduate university courses, following the conceive, design, implement, and operate (CDIO) approach to modern engineering education. It describes ESE as implemented by the author and his research team in the Space Systems Engineering courses at Skoltech over the course of Fall 2014–Spring 2017. It describes the experience of student cohorts in applying SE to stratospheric balloon missions for education purposes, simulating real-life project experience including customer interface management, and operating projects designing and implementing an SE management plan. It describes the proposed approach and provides lessons learnt to generalize ESE to any specific engineering discipline of interest. A mapping between the learning objectives of ESE and the CDIO education framework is proposed. It extends the concept of hands-on SE education. It will be useful to educators interested in novel approaches to SE education and to experiment new ways to deliver a subject that is traditionally believed difficult to teach in university.

Conjugation of growth factors to a carrier is a favorable method to improve their efficacy as therapeutic molecules. Here, we report the carrier size effect on bioactivity of human epidermal growth factor (hEGF) conjugated to polystyrene particles. BALB/3T3 cells were treated with hEGF-conjugated particles (hEGF-conjs) sized from 20 to 1000 nm. At hEGF concentrations less than 0.5 ng ml−1, free hEGF was more potent than the hEGF-conjs at inducing cell proliferation. However, cell proliferation was size-dependent at higher concentrations of hEGF i.e.hEGF-conjs sized equal to or less than 200 nm displayed lower cell proliferation, compared to free hEGF, but larger particles showed increased cell proliferation. This is in agreement with previous studies showing accumulation of activated-EGFRs in early endosomes triggers apoptosis of A431 and HeLa cells. The confocal microscopy and co-localization fluorescence staining showed the 500 and 1000 nm hEGF-conjs exclusively remained on the cell surface, probably enabling them to activate EGF receptors for a longer time. Conversely, smaller particles were mostly inside the cells, indicating their rapid endocytosis. Similarly, A431 cells treated with 20 nm hEGF-conj, endocytosed the particles and experienced decreased cell proliferation, while the 500 and 1000 nm hEGF-conjs were not internalized, and induced partial cell proliferation. Moreover, we showed multivalency of hEGF-conjs is not the cause of enhanced cell proliferation by large particles, as the degree of EGFR phosphorylation by free EGF was higher, compared to hEGF-conjs. Our results suggest the potential of micron-sized particles as a carrier for hEGF to enhance cell proliferation, which could be explored as a promising approach for topical application of growth factors for accelerating wound healing.

Purpose: The elimination of abdominal tumors by percutaneous cryoablation has been shown to be an effective and less invasive alternative to open surgery. Cryoablation destroys malignant cells by freezing them with one or more cryoprobes inserted into the tumor through the skin. Alternating cycles of freezing and thawing produce an enveloping iceball that causes the tumor necrosis. Planning such a procedure is difficult and time-consuming, as it is necessary to plan the number and cryoprobe locations and predict the iceball shape which is also influenced by the presence of heating sources, e.g., major blood vessels and warm saline solution, injected to protect surrounding structures from the cold. Methods: This paper describes a method for fast GPU-based iceball modeling based on the simulation of thermal propagation in the tissue. Our algorithm solves the heat equation within a cube around the cryoprobes tips and accounts for the presence of heating sources around the iceball. Results: Experimental results of two studies have been obtained: an ex vivo warm gel setup and simulation on five retrospective patient cases of kidney tumors cryoablation with various levels of complexity of the vascular structure and warm saline solution around the tumor tissue. The experiments have been conducted in various conditions of cube size and algorithm implementations. Results show that it is possible to obtain an accurate result within seconds. Conclusion: The promising results indicate that our method yields accurate iceball shape predictions in a short time and is suitable for surgical planning.

This paper defines Federations of Systems, introduces a tailored architecting framework, and demonstrates it in a satellite design case study. While certainly not being new concepts in the literature, federations are a class of Systems of Systems (SoS) that have not been extensively explored due to the scarcity of applied examples and still few practitioners facing their specific design challenges. This is expected to change with the advent of the Internet of Things, Machine to Machine applications, collaborative consumption, and Federated Satellite Systems. It has become henceforth necessary to develop approaches in design and architecting capable of addressing such interconnected sets of systems. Federations are SoS characterized by the absence of global goals and stakeholders, and cooperation enabled only on an opportunistic basis. Systems engage in federations when the perceived benefit exceeds the costs of the necessary interfaces. The proposed framework quantifies the upper limits to the net benefits of cooperation between systems through the concept of synergy. Using synergy as a heuristic to navigate federated design spaces, the framework predicts the appearance and evolution of federations. The demonstration of the framework in a six‐satellite federation shows that advantages of federating emerge with the collaboration between just two systems. Interface costs, architectural cost preferences, and network topology drive the achievable benefits. Specifically, when considering communication architectures under 80 MUSD for satellite systems, federating is advantageous when the interface lifecycle costs are below 15 MUSD. This demonstration case exemplifies how federating can assist systems in achieving design points that dominate the solutions of their local tradespace.

The oral microbiome potentially wields significant influence in the development of cancer. Within the human oral cavity, an impressive diversity of more than 700 bacterial species resides, making it the second most varied microbiome in the body. This finely balanced oral microbiome ecosystem is vital for sustaining oral health. However, disruptions in this equilibrium, often brought about by dietary habits and inadequate oral hygiene, can result in various oral ailments like periodontitis, cavities, gingivitis, and even oral cancer. There is compelling evidence that the oral microbiome is linked to several types of cancer, including oral, pancreatic, colorectal, lung, gastric, and head and neck cancers. This review discussed the critical connections between cancer and members of the human oral microbiota. Extensive searches were conducted across the Web of Science, Scopus, and PubMed databases to provide an up-to-date overview of our understanding of the oral microbiota’s role in various human cancers. By understanding the possible microbial origins of carcinogenesis, healthcare professionals can diagnose neoplastic diseases earlier and design treatments accordingly.

Percutaneous procedures allow interventional radiologists to perform diagnoses or treatments guided by an imaging device, typically a computed tomography (CT) scanner with a high spatial resolution. To reduce exposure to radiations and improve accuracy, robotic assistance to needle insertion is considered in the case of X-ray guided procedures. We introduce a planning algorithm that computes a needle placement compatible with both the patient’s anatomy and the accessibility of the robot within the scanner gantry. Our preoperative planning approach is based on inverse kinematics, fast collision detection, and bidirectional rapidly exploring random trees coupled with an efficient strategy of node addition. The algorithm computes the allowed needle entry zones over the patient’s skin (accessibility map) from 3D models of the patient’s anatomy, the environment (CT, bed), and the robot. The result includes the admissible robot joint path to target the prescribed internal point, through the entry point. A retrospective study was performed on 16 patients datasets in different conditions: without robot (WR) and with the robot on the left or the right side of the bed (RL/RR). We provide an accessibility map ensuring a collision-free path of the robot and allowing for a needle placement compatible with the patient’s anatomy. The result is obtained in an average time of about 1 min, even in difficult cases. The accessibility maps of RL and RR covered about a half of the surface of WR map in average, which offers a variety of options to insert the needle with the robot. We also measured the average distance between the needle and major obstacles such as the vessels and found that RL and RR produced needle placements almost as safe as WR. The introduced planning method helped us prove that it is possible to use such a “general purpose” redundant manipulator equipped with a dedicated tool to perform percutaneous interventions in cluttered spaces like a CT gantry.

Segmentation of liver tumours is an important part of the 3D visualisation of the liver anatomy for surgical planning. The spatial relationship between tumours and other structures inside the liver forms the basis of preoperative surgical risk assessment. However, the automatic segmentation of liver tumours from abdominal CT scans is riddled with challenges. Tumours located at the border of the liver impose a big challenge as the surrounding tissues could have similar intensities. In this work, we introduce a fully automated liver tumour segmentation approach in contrast-enhanced CT datasets. The method is a multi-stage technique which starts with contrast enhancement of the tumours using anisotropic filtering, followed by adaptive thresholding to extract the initial mask of the tumours from an identified liver region of interest. Localised level set-based active contours are used to extend the mask to the tumour boundaries. The proposed method is validated on the IRCAD database with pathologies that offer highly variable and complex liver tumours. The results are compared quantitatively to the ground truth, which is delineated by experts. We achieved an average dice similarity coefficient of 75% over all patients with liver tumours in the database with overall absolute relative volume difference of 11%. This is comparable to other recent works, which include semiautomated methods, although they were validated on different datasets. The proposed approach aims to segment tumours inside the liver envelope automatically with a level of accuracy adequate for its use as a tool for surgical planning using abdominal CT images. The approach will be validated on larger datasets in the future.

ABSTRACTDroop control is the conventional way to share the demand power among the generators in a microgrid. Analyzing this control method shows that it has poor performance in reactive power sharing. Generated reactive power of each microsource depends on the active load demand. In this paper, a control method is proposed to improve the reactive power sharing performance. It is indicated that higher reactive power droop gains make the generated reactive power to be less influenced from the changes in active load. However, high droop gains can lead the system to instability. Hence considering eigenvalue analysis of the microgrid, a new auxiliary controller is proposed to damp the oscillations caused by high droop gains. In the new method, there is not the need for monitoring the grid impedance to tune the controllers. To verify the proposed method, load step is applied to a test microgrid and the results are shown. In the new method, total generated reactive power is reduced in comparison to the conventional droop controller and the system stability is maintained.

Design methods for federated systems must consider local incentives and interactive effects among independent decision-makers. This paper extends value-centric design methodology to multi-actor cases by using game-theoretic principles. Federated systems are represented as a Stag Hunt game where players choose between independent (noncooperative) and federated (cooperative) strategies. Risk arises from the possibility of withdrawn cooperation and can be quantitatively assessed for particular design alternatives with subjective estimates of the probability for cooperation and objective measures such as the weighted average log measure of risk. The value of cooperation can be bounded below by designing for the independent strategy and above by designing for a centralized strategy controlled by a single authority. An application case considers a stylized system value model of a distributed satellite system with two players and symmetric design decisions. Results demonstrate lower and upper bounds to the value of a federated strategy with opportunistic, fixed-cost communication services. Quantitative risk analysis shows the value-maximizing federated design under mutual cooperation carries risk which can be mitigated by more conservative design alternatives with only minor loss of value.

Selenium binds some enzymes such as glutathione peroxidase and thioredoxin reductase, which may be activated in biological infections and oxidative stress. Chemical and physical methods for synthesizing nanoparticles, apart from being expensive, have their own particular risks. However, nanoparticle synthesis through green chemistry is a safe procedure that different biological sources such as bacteria, fungi, yeasts, algae and plants can be the catalyst bed for processing. Synthesis of selenium nanoparticles (SeNPs) by macro/microorganisms causes variation in morphology and shape of the particles is due to diversity of reduction enzymes in organisms. Reducing enzymes of microorganisms by changing the status of redox convert metal ions (Se2−) to SeNPs without charge (Se0). Biological activity of SeNPs includes their protective role against DNA oxidation. Because of the biological and industrial properties, SeNPs have wide applications in the fields of medicine, microelectronic, agriculture and animal husbandry. SeNPs can show strong antimicrobial effects on the growth and proliferation of microorganisms in a dose-dependent manner. The objective of this review is to consider SeNPs applications to various organisms.

This paper develops a framework to simulate and evaluate pricing policies of spacecraft trading commodities, such as data routing, in a federated satellite network. Federated satellite systems allow the reallocation of underutilized assets, enabling their use as services between owners and third parties. The paper, by means of game theory, focuses on sealed‐bid reverse auction pricing schemes, benchmarks first‐price and second‐price auction strategies, and evaluates the associated trade‐offs in terms of performance and cost, and losses in Pareto efficiency introduced by system‐level operation constraints. The analysis considers an application case study for federated satellite systems operating in Low Earth Orbit for commercial purposes. Satellite federations are a novel paradigm envisioning on‐orbit opportunistic sharing of resources through an ad hoc mobile satellite network. The architecture creates the basis for the realization of a commercial cloud computing environment in orbit, with spacecraft establishing communications links between each other leveraging on system design margins. The results of the case study in space provide new insights on the design of federated satellites and their operations while characterizing emergent behaviors and efficient trade‐offs on the Pareto front of the cost–performance curve.

In this paper an analytical approach is conducted to evaluate the droop control method in an islanding microgrid. Droop control is the key solution for sharing the demand power between generators in autonomous microgrids where there is no support from the electricity distribution grid. In the paper, three important load types are investigated to verify the droop control performance. First, coupling of active power and reactive power is considered in the microgrid and a new method is proposed to facilitate separate control of powers. In the proposed method the effects of droop gains on decoupling of active power and reactive power control, voltage regulation, power oscillation and system stability are studied. In the second load type study, by applying the different types of faults, induction motor characteristics are observed. By simulation results it is shown that the fault intensity and duration will determine how the microgrid attains to fast frequency convergence and how fast protection system operation can improve system stability. In the third case, imbalanced nonlinear load is studied in the microgrid and the influences of embedded controllers on harmonic distortion, system balance and voltage regulation are observed.

This protocol describes how to assess indirectly acquired threat responses in humans. The reaction to the emotional expressions of others is determined by measuring skin conductance responses.

Lead halide perovskite semiconductors are in general known to have an inherently high X-ray absorption cross-section and a significantly higher carrier mobility than any other low-temperature solution-processed semiconductor. So far, the processing of several-hundred-micrometres-thick high-quality crystalline perovskite films over a large area has been unresolved for efficient X-ray detection. In this Article, we present a mechanical sintering process to fabricate polycrystalline methyl ammonium lead triiodide perovskite (MAPbI3) wafers with millimetre thickness and well-defined crystallinity. Benchmarking of the MAPbI3wafers against state-of-the-art CdTe detectors reveals competitive conversion efficiencies of 2,527 µC Gyair−1cm−2under 70 kVpX-ray exposure. The high ambipolar mobility–lifetime product of 2 × 10−4cm2V−1is suggested to be responsible for this exceptionally high sensitivity. Our findings inform a new generation of highly efficient and low-cost X-ray detectors based on perovskite wafers.

The article discusses how the nuclear deal has reconfigured the political landscape of Iran. Topics discussed include Hassan Rouhani's victory in the 2013 Iranian Presidential election, signing of the nuclear agreement between Iran and six countries in 2015, creation of new coalitions, and ideologies in Iran's political sphere like reformists.

Purpose – The purpose of this paper is to investigate the DC-Link voltage regulation of fuel cell electric vehicle (FCEV) with hybrid power source (HPS). The HPS consists of fuel cell (FC) as the main source and ultracapacitor (UC) as the auxiliary source in order to compensate for the slow dynamics of FC in transient conditions. The system is a multiconverter structure which is comprised of a boost DC/DC converter and a buck-boost converter connecting FC and UC to DC-link, respectively. Design/methodology/approach – The FCEV is modeled dynamically, considering the nonlinear behavior of HPS and multiconverter system. This paper presents an advanced control approach based on the control Lyapunov function to regulate the DC-link voltage and impeccable tracking of UC current to its references. The stability analysis of closed loop system is also insured. Findings – The performance of proposed controller is illustrated via Simulink® using numerical simulations under European Extra Urban Driving Cycle. The simulation results show that the presented method is both satisfactory and consistent with expectation. Originality/value – The proposed control method is state of the art in FCEV and improves the energy management system. [ABSTRACT FROM AUTHOR]

As a viable solution to long-term stability problems associate with DNA molecular wires along with the additional benefits of tuning their conductivity, hybrid DNA molecular wires made of natural base-pairs and synthetic base-pairs, which have lower ionization potentials and a more p orbital overlapping, offer an attractive option. A strong synthetic nucleotide candidate is tricyclic cytosine analogue (such as (8-MeO)tC), which we show has (i) a lower ionization potential (~ 0.65V) compared to natural nucleotides, G (1.29V), C (1.6V), A (1.42V), T (1.7V) and (ii) more p-orbital stacking due to its tricyclic structure. Moreover, to illuminate the importance of the p orbital stack to the conductivity of DNA molecular wires, in this paper, we compared the conductivity of wild-type (WT) DNA and DNA sequences containing mismatched base-pairs that perturb the p orbital stack. Lower conductivity was obtained when modifying the surface of the gold electrodes with both WT and mismatched DNA. Further, chips functionalized with DNA sequences with mismatched base-pairs were observed to have lower conductivity than those functionalized with WT DNA sequences.

Oral administration of insulin can be the most favorable route of administration for the diabetic patients. However, insulin as a biopharmaceutical is susceptible to the harsh conditions in the gastrointestinal tract leading to the destruction of its chemical structure and bioactivity.

[Display omitted]

Joint stiffness has been extensively used to study joint biomechanics. It can be described by a block-oriented, nonlinear, parallel-cascade structure under quasi-stationary conditions defined by the joint operating point. The model parameters are modulated dramatically during functional tasks where the joint operating point is varied with time. This paper reviews three parametric methods developed by our laboratory to identify joint stiffness: a refined instrumental variable method for transfer function identification of time-invariant stiffness, a MOESP subspace method for state-space identification of time-invariant stiffness, and a linear parameter varying subspace method for time-varying stiffness. The effectiveness of each method is demonstrated using experimental data recorded during posture and movement.

The Hammerstein system provides a good model for the stretch reflex contribution to joint stiffness under quasi-stationary conditions. However, the model parameters change dramatically with the operating point defined by the joint angular position and muscle activation. Both position and activation level undergo large, rapid changes during movement and consequently reflex stiffness will be timevarying. Our laboratory has developed a series of algorithms to identify time-varying Hammerstein systems using approaches involving: large input-output ensembles, multiple short segments, temporal expansion, and linear parameter variation. This paper reviews these methods and evaluates their relative strengths and weaknesses.

This work studies the dynamic relationship between the electrical activity produced in skeletal muscles and recorded using electromyogram(EMG), and torque at the healthy human ankle during isometric contractions. Subjects were instructed to voluntarily modulate their ankle torque by tracking a pseudo-random visual command signal. Impulse response functions (IRF) estimated between the EMG and torque records had an unphysiological anticipatory component suggesting that the estimated IRF was biased because the data were recorded in closed-loop. Applying a closed-loop identification algorithm that modeled the EMG-torque relation as a nonparametric impulse response function, and the noise as an autoregressive-moving-average process gave unbiased results. The EMG-torque IRF had second-order, low-pass, dynamics, whose properties varied with the mean torque.

Matching high ambitions with scarce resources is one of the primary challenges of aerospace and other industries concerned with the development of unprecedented infrastructures, on par with the technical challenges associated with developing new technology. Stakeholder objectives are often unclear due to highly exploratory business cases. Further ambiguity emerges from disagreement between stakeholders and decision makers called to formulate scientific, technological and policy requirements for new systems.

Reactive oxygen species have effects on gamete quality and gamete interaction; they influence spermatozoa, oocytes, embryos, and their environment. In this study, we evaluated the antioxidant effect of different concentrations of saffron (Crocus sativusL.) aqueous extract (SAE) and its ingredient, crocin, on the improvement of in vitromaturation (IVM) and subsequent in vitrofertilization (IVF) and embryo development of mouse oocytes.

We investigated predictors for acute and persisting periprocedural ischemic brain lesions among patients with symptomatic carotid stenosis randomized to stenting or endarterectomy in the International Carotid Stenting Study.

The aim of this paper is to investigate a novel approach for output feedback damping controller design of the static synchronous compensator (STATCOM) in order to enhance the damping of power system low frequency oscillations (LFO). The design of output feedback controller is considered as an optimization problem according to the time domain-based objective function solved by a honey bee mating optimization (HBMO) algorithm that has a strong ability to find the most optimistic results. To validate the accuracy of results a comparison with genetic algorithm (GA) has been made. The effectiveness of the proposed controller are tested and demonstrated through eigenvalue analysis and nonlinear time-domain simulation studies over a wide range of loading conditions. The simulation study shows that the designed controller by HBMO performs better than GA in finding the solution.

In human research, studies of return of fear (ROF) phenomena, and reinstatement in particular, began only a decade ago and recently are more widely used, e.g., as outcome measures for fear/extinction memory manipulations (e.g., reconsolidation). As reinstatement research in humans is still in its infancy, providing an overview of its stability and boundary conditions and summarizing methodological challenges is timely to foster fruitful future research. As a translational endeavor, clarifying the circumstances under which (experimental) reinstatement occurs may offer a first step toward understanding relapse as a clinical phenomenon and pave the way for the development of new pharmacological or behavioral ways to prevent ROF. The current state of research does not yet allow pinpointing these circumstances in detail and we hope this review will aid the research field to advance in this direction. As an introduction, we begin with a synopsis of rodent work on reinstatement and theories that have been proposed to explain the findings. The review however mainly focuses on reinstatement in humans. We first describe details and variations of the experimental setup in reinstatement studies in humans and give a general overview of results. We continue with a compilation of possible experimental boundary conditions and end with the role of individual differences and behavioral and/or pharmacological manipulations. Furthermore, we compile important methodological and design details on the published studies in humans and end with open research questions and some important methodological and design recommendations as a guide for future research.

n addition to electrical design and function, corrosion resistance is an important factor in producing earth rod and plate which indicate quality of these products. The ability of an electrical grounding component to resist corrosion determines its service life.Different production methods has been tried to reach the maximum corrosion resistance but electro deposition process specially alloyed covering used in this research is the most successful method. In this research innovation of the invented process is described, then to confirm the method, corrosion resistance of the covered Earth rod and plate is tested. Phenomenal results indicated that even with 100 micron thickness of the new coating layer, corrosion resistance reaches the required time of resistance. Also by increasing the layer thickness, corrosion resistance is increased.