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Copyright of International Journal of Engineering Research & Development (IJERAD) is the property of International Journal of Engineering Research & Development and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of South China University of Technology (Natural Science Edition) is the property of South China University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Cancer stem cells (CSCs) are defined as a subpopulation of malignant tumor cells with selective capacities for tumor initiation, self‐renewal, metastasis, and unlimited growth into bulks, which are believed as a major cause of progressive tumor phenotypes, including recurrence, metastasis, and treatment failure. A number of signaling pathways are involved in the maintenance of stem cell properties and survival of CSCs, including well‐established intrinsic pathways, such as the Notch, Wnt, and Hedgehog signaling, and extrinsic pathways, such as the vascular microenvironment and tumor‐associated immune cells. There is also intricate crosstalk between these signal cascades and other oncogenic pathways. Thus, targeting pathway molecules that regulate CSCs provides a new option for the treatment of therapy‐resistant or ‐refractory tumors. These treatments include small molecule inhibitors, monoclonal antibodies that target key signaling in CSCs, as well as CSC‐directed immunotherapies that harness the immune systems to target CSCs. This review aims to provide an overview of the regulating networks and their immune interactions involved in CSC development. We also address the update on the development of CSC‐directed therapeutics, with a special focus on those with application approval or under clinical evaluation. [ABSTRACT FROM AUTHOR]

Broadband noise due to the turbulence-aerofoil interaction, which is also called the leading edge noise, is one of the major noise sources of aircraft (including the engine). To study the noise properties numerically is a popular approach with the increasing power of computers. Conventional approaches of using body-fitted grids at the boundaries would be convoluted due to the complex geometries, which can constrain the efficiency of parametric studies. A promising approach to tackle this issue is to use the immersed boundary method (IBM). Among various IBM variants, the volume penalization (VP) approach employs a masking function to identify the immersed solid boundary, and continuous forcing terms are added to the original flow governing equations to account for the boundary conditions. It is, therefore, efficient and easy to implement into the existing computational aeroacoustics solvers. In this work, the VP-based IBM is used to simulate the leading edge noise by combining with the advanced synthetic turbulence method. The simulations are conducted for both the isolated aerofoils and cascade, and the results are compared with the well-validated body-fitted grid solutions. The viscosity effect is also highlighted by comparing the results obtained by solving both Euler and Navier–Stokes equations. [ABSTRACT FROM AUTHOR]

Aeroelastic instabilities such as flutter have a crucial role in limiting the operating range and reliability of turbomachinery. This paper offers an alternative approach to aeroelastic analysis, where the sensitivity of aerodynamic damping with respect to main flow and structural parameters is quantified through a surrogate-model-based investigation. The parameters are chosen based on previous studies and are represented by a uniform distribution within applicable intervals. The surrogate model is an artificial neural network, trained and tested to achieve an error within 1% of the test data. The quantity of interest is aerodynamic damping and the datasets are obtained from a linearised aeroelastic solver. The sensitivity of aerodynamic damping with respect to the input variables is obtained by calculating normalised gradients from the surrogate model at specific operating conditions. The results show a quantitative comparison of sensitivity across the different input parameters. The outcome of the sensitivity analysis is then used to decide the most appropriate action to take in order to induce stability in unstable operating conditions. The work is a preliminary study, carried out on a simplified two dimensional compressor cascade and it is aimed at proving the validity of a data-driven approach in studying the aeroelastic behaviour of turbomachinery. To the best of the authors' knowledge, this is the first time a data-driven flutter model has been investigated. The initial results are encouraging, indicating that this approach is worth pursuing in the future. The presented framework can be used as a redesign tool to enhance the flutter stability of an existing blade. [ABSTRACT FROM AUTHOR]

The aim of this work is to study the influence of different subgrid-scale (SGS) closure models and inflow turbulence conditions on the boundary layer transition on the suction side of a highly loaded transonic turbine cascade in the presence of high free-stream turbulence using large eddy simulations (LES) of the MUR237 test case. For the numerical simulations, the MUR237 flow case was considered and the incoming free-stream turbulence was reproduced using the synthetic eddy method (SEM). The boundary layer transition on the blade suction side was found to be significantly influenced by the choice of the SGS closure model and the SEM parameters. These two aspects were carefully evaluated in this work. Initially, the influence of three different closure models (Smagorinsky, WALE, and subgrid-scale kinetic energy model) was evaluated. Among them, the WALE SGS closure model performed best compared to the Smagorinsky and KEM models and, for this reason, was used in the following analysis. Finally, different values of the turbulence length scale, eddies density, and inlet turbulence for the SEM were evaluated. As shown by the results, among the different parameters, the choice of the turbulence length scale plays a major role in the transition onset on the blade suction side. [ABSTRACT FROM AUTHOR]

The paper presents a detailed analysis of particle image velocimetry (PIV) measurements performed in a turbine cascade representative of highly accelerated low-pressure turbine (LPT) blades. Two cameras have been simultaneously used to observe a great portion of the suction side boundary layer with the highest possible spatial resolution, thus allowing us to solve the interaction process between impinging upstream wakes and the blade boundary layer. Four unsteady inflow conditions, characterized by different incoming wake reduced frequencies and flow coefficients, have been examined at fixed Reynolds number. The highly resolved flow fields have been processed to explore reduced frequency and flow coefficient effects on the boundary layer unsteady transition process and, consequently, on loss production. For a deep physical insight on the mechanisms responsible for loss generation, proper orthogonal decomposition (POD) has been applied at different phases of the wake passing period. This has provided the dominant structures affecting the cascade aerodynamics during the wake period. Moreover, the examination of POD modes has allowed us to show the effects induced by the parameter variation on the turbulent kinetic energy production and thus to the unsteady loss production mechanisms. [ABSTRACT FROM AUTHOR]

Unsteady pressure fluctuations measured by fast-response pressure transducers mounted in a low-pressure turbine cascade are compared to unsteady simulation results. Three differing simulation approaches are considered, one time-integration method and two harmonic balance methods either resolving or averaging the time-dependent components within the turbulence model. The observations are used to evaluate the capability of the harmonic balance solver to predict the transient pressure fluctuations acting on the investigated stator surface. Wakes of an upstream rotor are generated by moving cylindrical bars at a prescribed rotational speed that refers to a frequency of f 500 Hz. The excitation at the rear part of the suction side is essentially driven by the presence of a separation bubble and is therefore highly dependent on the unsteady behavior of turbulence. In order to increase the stability of the investigated harmonic balance solver, a developed Lanczos-type filter method is applied if the turbulence model is considered in an unsteady fashion. [ABSTRACT FROM AUTHOR]

One way to reduce waste and to make a system more robust is to allow its components to pool resources. For example, banks might insure each other or share a common capital reserve. Systems whose resources have been pooled in this way are highly prevalent in such diverse domains as finance, infrastructure, health care, emergency response and engineering. However, these systems have a combination of characteristics that leave them vulnerable to poor decision-making: non-linearity of risk; obvious rewards combined with hidden costs; and political and market incentives that encourage inadequate safety margins. Three studies demonstrate a tendency for managers of such systems to underestimate the probability of cascading failures. We describe a series of behaviorally based policy interventions to mitigate the resulting hazards. [ABSTRACT FROM AUTHOR]

In a cluster crystal, each lattice site is occupied by multiple soft-core particles. As the number density is increased at zero temperature, a "cascade" of isostructural phase transitions can occur between states whose site occupancy differs by unity. For low but finite temperature, each of these transitions terminates in a critical point. Using tailored Monte Carlo simulation techniques, we have studied such demixing cascades in systems of soft particles interacting via potentials of the generalized exponential form u(r) = ∈∈ exp [-(r/σ)n].We have estimated the critical parameters of the first few transitions in the cascade as a function of the softness parameter n. The critical temperature and pressure exhibit non-monotonic behavior as n is varied, although the critical chemical potential remains monotonic. The trends for the pressure and chemical potential are confirmed by cell model calculations at zero temperature. As n →2 +, all the transitions that we have observed are preempted by melting although we cannot rule out that clustering transitions survive at high density. [ABSTRACT FROM AUTHOR]

Complex systems are challenging to control because the system responds to the controller in a nonlinear fashion, often incorporating feedback mechanisms. Interdependence of systems poses additional difficulties, as cross-system connections enable malicious activity to spread between layers, increasing systemic risk. In this paper we explore the conditions for an optimal control of cascading failures in a system of interdependent networks. Specifically, we study the Bak–Tang–Wiesenfeld sandpile model incorporating a control mechanism, which affects the frequency of cascades occurring in individual layers. This modification allows us to explore sandpile-like dynamics near the critical state, with supercritical region corresponding to infrequent large cascades and subcritical zone being characterized by frequent small avalanches. Topological coupling between networks introduces dependence of control settings adopted in respective layers, causing the control strategy of a given layer to be influenced by choices made in other connected networks. We find that the optimal control strategy for a layer operating in a supercritical regime is to be coupled to a layer operating in a subcritical zone, since such condition corresponds to reduced probability of inflicted avalanches. However this condition describes a parasitic relation, in which only one layer benefits. Second optimal configuration is a mutualistic one, where both layers adopt the same control strategy. Our results provide valuable insights into dynamics of cascading failures and and its control in interdependent complex systems. [ABSTRACT FROM AUTHOR]

We perform a power spectral analysis of magnetic field fluctuations measured by the Rosetta spacecraft's magnetometer at comet 67P/Churyumov-Gerasimenko. We interpret the power spectral signatures in terms of plasma turbulent processes and discover that different turbulent processes are prominent during different active phases of the comet. During the weakly active phase of the comet, dominant injection is prominent at low frequencies near 10-2 Hz, while partial energy cascade or dispersion is prominent at high frequencies near 10-1 Hz. During the intermediately active phase, uniform injection is prominent at low frequencies, while partial energy cascade or dispersion is prominent at high frequencies. During the strongly active phase of the comet, we find that partial energy cascade or dissipation is dominant at low frequencies, while partial energy cascade, dissipation, or dispersion is dominant at high frequencies. We infer that the temporal variations of the turbulent processes occur due to the evolution of the plasma environment of the comet as it orbits the Sun. [ABSTRACT FROM AUTHOR]

Cooling systems have been widely studied over the past few years, but there are little researches on cascade cooling system containing different cooling methods. Cascade cooling system is suitable for the hot stream cooling process with large temperature variation. A new cascade cooling system containing waste heat recovery, air cooling, water cooling, absorption refrigeration and compression refrigeration is proposed. In this system, hot water is used to recycle waste heat from the hot stream, then drive the absorption refrigeration cycle (ARC), providing refrigerant water for hot stream cooling process. The mass flowrate of hot water determines the amount of waste heat recovered, and the final hot water temperature affects the thermal efficiency of ARC. Both the flowrate and the final temperature of hot water influence the cooling capacity generated by ARC, and further affect the heat load distribution of cascade cooling system. The hot water mass flowrate is a critical decision variable for the optimal design of the system. This study develops a model for the techno-economic optimization of cascade cooling system with ARC. ARC is modelled using thermodynamics with the concept of state points. The proposed model determines the optimal heat load distribution of cascade cooling system and the optimal design of ARC, with the minimum total annual cost (TAC) simultaneously. The effectiveness of this method is demonstrated with a case study in a polysilicon enterprise. [ABSTRACT FROM AUTHOR]

Understanding the response of ecological networks to perturbations and disruptive events is needed to anticipate the biodiversity loss and extinction cascades. Here, we study how network plasticity reshapes the topology of mutualistic networks in response to species loss. We analyze more than one hundred empirical mutualistic networks and considered random and targeted removal as mechanisms of species extinction. Network plasticity is modeled as either random rewiring, as the most parsimonious approach, or resource affinity-driven rewiring, as a proxy for encoding the phylogenetic similarity and functional redundancy among species. This redundancy should be positively correlated with the robustness of an ecosystem, as functions can be taken by other species once one of them is extinct. We show that effective modularity, i.e. the ability of an ecosystem to adapt or restructure, increases with increasing numbers of extinctions, and with decreasing the replacement probability. Importantly, modularity is mostly affected by the extinction rather than by rewiring mechanisms. These changes in community structure are reflected in the robustness and stability due to their positive correlation with modularity. Resource affinity-driven rewiring offers an increase of modularity, robustness, and stability which could be an evolutionary favored mechanism to prevent a cascade of co-extinctions. [ABSTRACT FROM AUTHOR]

A comparative experimental analysis is performed on pulsed suction (PS) and pulsed blowing (PB) used to control flow separations in a highly loaded compressor cascade. The effectiveness of the control methods is assessed via oil-flow visualization and steady and unsteady pressure measurements. Firstly, the control effect of the PS is evaluated by comparing the conventional steady continuous suction (SCS). A more efficient control effect is achieved by the PS compared to the SCS. Additionally, in order to further explore the potentials of the PS and PB and gain some insight into their controlling mechanisms, some important excitation parameters including excitation location, momentum coefficient and frequency are comparatively investigated in detail. It is found that the PS and PB are both able to improve the cascade performance by effectively suppressing the passage vortex. With the excitation location moving downstream, the almost opposite change trends for the PS and PB on the total pressure loss and energy efficiency are shown. The PS has an advantage over the PB in improving the cascade performance at the same average excitation momentum. But there is a slighter change of the losses for the PB cases at different excitation frequencies relative to the PS ones, indicating that the PB is more insensitive to the excitation frequency. Based on the optimal excitation parameters, the total pressure loss coefficients for the PS and PB are reduced by 11.3% and 10.3%, respectively. Furthermore, the effectiveness of the PS and PB is also corroborated at a larger incidence angle. [ABSTRACT FROM AUTHOR]

We investigate the spin-dependent transport in aperiodic cascade junctions of semiconductors, where semiconductors are arranged in the Thue-Morse sequence. We have calculated the spin-dependent transmission and the spin polarization with a transfer matrix method in these cascade junctions. It is shown that a spin-dependent bandgap structure appears by changing the generation and the Rashba spin-orbit wave vector. As a result, around resonant wave vectors, high spin polarization has been observed and the spin polarization has been reversed, and the spin conductance exists the value of zero by tuning the Rashba spin-orbit coupling. Our investigations may provide a way to design spin filters and spin switches. [ABSTRACT FROM AUTHOR]

Information about intermolecular potentials is usually obtained through the analysis of the absorption line shapes recorded in the frequency domain. This approach is also adopted to study the effects of motional narrowing and speed dependence of the pressure broadening coefficients. On the other hand, time domain measurements are directly related to molecular collisions and are therefore frequently employed to study molecular relaxation rates, as well as the effects of velocity changing collisions and the speed dependence of the absorption cross sections. Intrapulse quantum cascade laser spectrometers are able to produce both saturation and molecular alignment of the gas sample. This is due to the rapid sweep of the radiation through the absorption features. In the present work the frequency down-chirped radiation emitted by an intrapulsed quantum cascade laser operating near 7.8 μm is employed to investigate the collisional relaxation processes, and the collisional narrowing, in the 150,15←161,16 and 151,15←160,16 doublet in the water vapor ν2 band. The effects of He, Ne, Ar, N2, and CO2 as collisional partners are investigated. The experimental results clearly indicate the dependence of the collisional cross sections upon the chirp rate. They also demonstrate that by using different chirp rates it is possible to gain information about the intermolecular processes driving the molecular collisions and the related energy transfer. [ABSTRACT FROM AUTHOR]

The gain coefficient of several GaAs/AlxGa1-xAs quantum-cascade lasers (QCLs) with a nominal Al content of x=0.45 has been calculated as a function of transition energy and electric field strength. We solve the Schrödinger and Poisson equations self-consistently in the framework of a linear scattering-rate model with periodic boundary conditions. The actual layer thicknesses as well as the Al content of the barriers have been obtained from x-ray diffraction. The calculated gain characteristics exhibit a large range of transition energies and a corresponding range of possible operating field strengths. These results may provide an explanation for the observation of a rather large range of the lasing energies for QCLs with nominally identical cascade structures. The comparison with the experimental values of the lasing energy reveals that most of the lasers operate below the designed field strength. The analysis of the operating field strengths and the threshold current densities indicates larger losses for higher field strengths probably due to leakage currents. [ABSTRACT FROM AUTHOR]

We have investigated the structural properties of Si/SiGe electroluiminescent quantum-cascade structures, by means of x-ray reflectivity and diffraction. The cascade structures were grown at a comparatively low temperature of T = 350 °C to avoid misfit dislcoation formation. Despite an overall thickness of the cascade structures of about 9000 Å and Ge contents of up to more than 40% in some of the SiGe wells, the entire stack of layers is indeed pseudomorphic with respect to the Si substrate. The analysis of x-ray reflectivity data yields a rather small rms interface roughness, which increases only slightly from 2 to 2.9 Å from the bottom to the top of the cascade structures. From x-ray reflectivity maps we obtain in addition the vertical and lateral correlation of the interface roughness. It turns out that for long range interface fluctuations the vertical correlation length is larger than for short range fluctuations. [ABSTRACT FROM AUTHOR]

Electron transport in GaAs/AlGaAs quantum cascade lasers operating in midinfrared is calculated self-consistently using an intersubband scattering model. Subband populations and carrier transition rates are calculated and all relevant electron-LO phonon and electron-electron scatterings between injector/collector, active region, and continuum resonance levels are included. The calculated carrier lifetimes and subband populations are then used to evaluate scattering current densities, injection efficiencies, and carrier backflow into the active region for a range of operating temperatures. From the calculated modal gain versus total current density dependencies the output characteristics, in particular the gain coefficient and threshold current, are extracted. For the original GaAs/Al[sub 0.33]Ga[sub 0.67]As quantum cascade structure [C. Sirtori et al., Appl. Phys. Lett. 73, 3486 (1998)] these are found to be g = 11.3 cm/kA and J[sub th] = 6 ± 1 kA/cm² (at T = 77 K), and g = 7.9 cm/kA and J[sub th] = 10 ± 1 kA/cm² (at T = 200 K), in good agreement with the experiment. Calculations shows that threshold cannot be achieved in this structure at T = 300 K, due to the small gain coefficient and the gain saturation effect, also in agreement with experimental findings. The model thus promises to be a powerful tool for the prediction and optimization of new, improved quantum cascade structures. [ABSTRACT FROM AUTHOR]

The article presents an exploration into the causes and conditions leading to the perpetuation of unpopular and inefficient social norms and the methods by which they can be forced to collapse. Questions are raised regarding the rationality of human behaviors and social norms, such as prejudices and counterintuitive behavior. An explanation is offered through an observer-ignorance model and mistaken assumptions due to individual paradigm biases. Several examples are given from social psychology, including the impacts of pluralistic ignorance, misrepresentation, and conformity. The additional mathematical model of information cascades is defined and utilized within this context to instigate norm and perception shifts.

This paper is concerned with the target tracking problem of an autonomous surface vehicle in the presence of a maneuvering target. The velocity information of target is totally unknown to the follower vehicle, and only the relative distance and angle between the target and follower are obtained. First, a reduced-order extended state observer is used to estimate the unknown relative dynamics due to the unavailable velocity of the target. Based on the reduced-order extended state observer, an antidisturbance guidance law for target tracking is designed. The input-to-state stability of the closed-loop target tracking guidance system is analyzed via cascade theory. Furthermore, the above result is extended to the case that collisions between the target and leader are avoided during tracking, and a collision-free target tracking guidance law is developed. The main feature of the proposed guidance law is twofold. First, the target tracking can be achieved without using the velocity information of the target. Second, collision avoidance can be achieved during target tracking. Simulation results show the effectiveness of the proposed antidisturbance guidance law for tracking a maneuvering target with the arbitrary bounded velocity. [ABSTRACT FROM AUTHOR]

Interaction of a nanosecond high-intensity pulsed ion beam with thin graphene films on copper substrates is analyzed. Methods of Raman spectroscopy are used to investigate the degree of graphene degradation depending on the integral implanted dose. The role of the substrate in the structural degradation of graphene irradiated by charged particle beams is demonstrated using the software package SRIM, intended for modeling radiative defect cascades under irradiation by charged particle beams, and the data on radiation resistance of graphene available in the literature. [ABSTRACT FROM AUTHOR]

The photochemistry of O2 adsorbed on Pd(111) has been studied as a function of the energy of the exciting photons in the range of hν=3.9–6.4 eV. The obtained data are reproduced by a proposed kinetic model considering photostimulated desorption and dissociation, whereby the latter gives rise to additional displacement processes. This modeling yields rate constants and, hence, cross sections for the respective processes. It is found that the cross sections for all processes rise exponentially with photon energy. This result motivates a study of the distribution of hot electrons generated by laser irradiation, and its decay via electron-hole pair scattering events resulting in a broad secondary electron distribution. The energetic and spatial distribution of these electrons is calculated. The probability for these electrons to tunnel into an adsorbate affinity level is modeled and compared to the observed photo cross sections. [ABSTRACT FROM AUTHOR]

Deals with a study which examined cascade emission and four-wave mixing parametric radiations in potassium. Experimental procedures; Results and discussion; Conclusions.

Deals with a study which investigated the correlation between sputtering and several features of individual atomic collision cascades in solids. Simulation of conditions; Results; Conclusion.

We present a gas sensing system based on quartz-enhanced photoacoustic spectroscopy (QEPAS) employing a monolithic distributed-feedback quantum cascade laser (QCL) array operated in a pulsed mode as a light source. The array consists of 32 quantum cascade lasers emitting in a spectral range from 1190 cm−1 to 1340 cm−1. The optoacoustic detection module was composed of a custom quartz tuning fork with a prong spacing of 1 mm, coupled with two micro-resonator tubes to enhance the signal-to-noise ratio. The QEPAS sensor was validated by detecting the absorption of the P- and R-branches of nitrous oxide. The measurements were performed by switching the array QCLs in sequence while tuning their operating temperature to retrieve the fine structure of the two N2O branches. A sensor calibration was performed, demonstrating a linear responsivity for N2O:N2 concentrations from 1000 down to 200 parts-per-million. With a 10 s lock-in integration time, a detection sensitivity of less than 60 parts-per-billion was achieved permitting the monitoring of nitrous oxide at global atmospheric levels. [ABSTRACT FROM AUTHOR]

Background: In mammals, flagellar hyperactivation is indispensable to sperm fertilization with oocytes in vivo, although there are species differences in regulatory mechanisms for this event. In this study, I reviewed researches regarding hyperactivation of bull and boar spermatozoa, in comparison with those of spermatozoa from other species. Methods: Recent publications regarding sperm hyperactivation were collected and summarized. Results (Main findings): In bull and boar spermatozoa, there are two types of hyperactivation "full‐type hyperactivation and nonfull‐type hyperactivation" which are equivalent to anti‐hock hyperactivation and pro‐hock hyperactivation of mouse spermatozoa, respectively, on the basis of the flagellar parts exhibiting asymmetrical beating. Full‐type hyperactivation is initiated in response to a rapid increase of cytoplasmic Ca2+ in the connecting/middle and principal pieces by the mobilization of this divalent ion from extracellular space and internal store through cation channels. Regulatory molecules for the increase of cytoplasmic Ca2+ in the connecting/middle pieces are probably different from those in the principal pieces. Conclusion: I have proposed a hypothesis on the regulation of full‐type hyperactivation by the distinct signaling cascades leading to the increase in cytoplasmic Ca2+ between the connecting/middle and principal pieces of bull and boar spermatozoa. [ABSTRACT FROM AUTHOR]

Copyright of Angewandte Chemie is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The shocks in a supersonic/transonic axial compressor can increase the pressure ratio and cause flow losses. Therefore, it is essential to organize the shock wave pattern in the flow passage to reduce these losses. This study uses a numerical simulation method to study the influences of the leading-edge radius, cascade solidity, and pre-compression on the aerodynamic performance of a supersonic cascade. The cascade is designed using the pre-compression method to reduce shock losses; the inlet Mach number is 2.0 and the total pressure ratio is approximately 3.4. The results indicate that the cascade efficiency and stall margin decrease with an increase in the leading-edge radius; however, when the leading-edge radius is less than 0.1 mm, the influences of its change decrease. As cascade solidity increases, the stall margin first increases and then decreases. The larger the degree of pre-compression, the smaller the Mach number in front of the first oblique passage shock and the higher the efficiency; however, a large pre-compression effect can cause the ending normal shock to move upstream, decreasing the stall margin. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the dynamics of a fourth-order normal form near a double Takens-Bogdanov bifurcation. The reduced system of this normal form possesses eight pairs of homoclinic orbits for certain parameter values. The nonlinear time transformation method is applied to obtain an analytical approximation of the homoclinic orbit in the perturbed system and to construct the homoclinic bifurcation curve as well. Using numerical continuation, period-doubling and homoclinic-doubling cascades emanating from a codimension-2 bifurcation point are found. A codimension-2 homoclinic-gluing bifurcation point at which several homoclinic orbits concerning the origin glue together to form a new homoclinic orbit is also obtained. It is shown that in the vicinity of these bifurcation points, the system may exhibit chaos and chaotic attractors. [ABSTRACT FROM AUTHOR]

A central challenge in sensory neuroscience involves understanding how neural circuits shape computations across cascaded cell layers. Here we attempt to reconstruct the response properties of experimentally unobserved neurons in the interior of a multilayered neural circuit, using cascaded linear-nonlinear (LN-LN) models. We combine non-smooth regularization with proximal consensus algorithms to overcome difficulties in fitting such models that arise from the high dimensionality of their parameter space. We apply this framework to retinal ganglion cell processing, learning LN-LN models of retinal circuitry consisting of thousands of parameters, using 40 minutes of responses to white noise. Our models demonstrate a 53% improvement in predicting ganglion cell spikes over classical linear-nonlinear (LN) models. Internal nonlinear subunits of the model match properties of retinal bipolar cells in both receptive field structure and number. Subunits have consistently high thresholds, supressing all but a small fraction of inputs, leading to sparse activity patterns in which only one subunit drives ganglion cell spiking at any time. From the model’s parameters, we predict that the removal of visual redundancies through stimulus decorrelation across space, a central tenet of efficient coding theory, originates primarily from bipolar cell synapses. Furthermore, the composite nonlinear computation performed by retinal circuitry corresponds to a boolean OR function applied to bipolar cell feature detectors. Our methods are statistically and computationally efficient, enabling us to rapidly learn hierarchical non-linear models as well as efficiently compute widely used descriptive statistics such as the spike triggered average (STA) and covariance (STC) for high dimensional stimuli. This general computational framework may aid in extracting principles of nonlinear hierarchical sensory processing across diverse modalities from limited data. [ABSTRACT FROM AUTHOR]

The present study is conducted to propose a new code for optimizing a multicomponent isotope separation cascade. An efficient code is developed using an enhanced TLBO algorithm with a novel mutation for calculating the optimal parameters. The results indicate that by implementing a new objective function derived from the combination of D function with total interstage flow rates, the optimum tapered cascade is more efficient than the optimal square one. Also, the best feed locations for the separation of the middle components in the square cascade are the middle stages. [ABSTRACT FROM AUTHOR]

Motivation: Gene regulatory networks (GRN) can be determined via various experimental techniques, and also by computational methods, which infer networks from gene expression data. However, these techniques treat interactions separately such that interdependencies of interactions forming meaningful subnetworks are typically not considered. Methods: For the investigation of network properties and for the classification of different (sub-)networks based on gene expression data, we consider biological network motifs consisting of three genes and up to three interactions, e.g. the cascade chain (CSC), feed-forward loop (FFL), and dense-overlapping regulon (DOR). We examine several conventional methods for the inference of network motifs, which typically consider each interaction individually. In addition, we propose a new method based on three-way ANOVA (ANalysis Of VAriance) (3WA) that analyzes entire subnetworks at once. To demonstrate the advantages of such a more holistic perspective, we compare the ability of 3WA and other methods to detect and categorize network motifs on large real and artificial datasets. Results: We find that conventional methods perform much better on artificial data (AUC up to 80%), than on real E. coli expression datasets (AUC 50% corresponding to random guessing). To explain this observation, we examine several important properties that differ between datasets and analyze predicted motifs in detail. We find that in case of real networks our new 3WA method outperforms (AUC 70% in E. coli) previous methods by exploiting the interdependencies in the full motif structure. Because of important differences between current artificial datasets and real measurements, the construction and testing of motif detection methods should focus on real data. [ABSTRACT FROM AUTHOR]

Grounded in Emotional Cascade Theory, we explored whether rumination and multisensory imagery-based cognitions moderated the relationships between affect and both odds of non-suicidal self-injury (NSSI), and frequency of the behaviour. A sample of 393 university students completed self-report questionnaires assessing the constructs of interest. Contrary to expectations, rumination did not emerge as a significant moderator of the affect-NSSI relationship. However, the relationship between affect and frequency of NSSI was moderated by the use of imagery. Further, the relationship between negative affect and NSSI was moderated by positive affect, underscoring the need to consider both negative and positive affect in models of NSSI. Most youth who self-injured reported thinking in images while the urge to self-injure was strong, with 53% thinking in images at least half the time. Future work is needed to explore how positive and negative affect work in concert to govern NSSI, and how imagery might either exacerbate or reduce risk of NSSI. [ABSTRACT FROM AUTHOR]

Separation in compressor cascade triggers flow loss and instability. This paper presents a passive flow control method by introducing a slot into the blade. The slot induces self-adapted jet, while the jet flow is used to suppress cascade’s separation. To study the flow control effect, experiments were conducted and flow field details were given by validated numerical simulations. The results show that a well-designed slot carries adequate jet airflow from pressure side (PS) to suction side (SS) due to the great pressure fall between the two sides. The jet airflow delays suction side separation within specific incidence angles, so the performance of cascade achieves considerable improvements. It enables to be concluded that the slot carries jet flow to SS separation zone, and then the self-adapted jet flow re-energizes low momentum fluid and suppresses vortices in the separation which are negative to the cascade flow. [ABSTRACT FROM AUTHOR]

In this work, we investigate the effects of the cascade architecture of dilated convolutions and the deep network architecture of multi-resolution input images on the accuracy of semantic segmentation. We show that a cascade of dilated convolutions is not only able to efficiently capture larger context without increasing computational costs, but can also improve the localization performance. In addition, the deep network architecture for multi-resolution input images increases the accuracy of semantic segmentation by aggregating multi-scale contextual information. Furthermore, our fully convolutional neural network is coupled with a model of fully connected conditional random fields to further remove isolated false positives and improve the prediction along object boundaries. We present several experiments on two challenging image segmentation datasets, showing substantial improvements over strong baselines. [ABSTRACT FROM AUTHOR]

A method of smoothing uneven dosing of microcomponents in continuous flows of granular materials by the action of a cascade of counter pulses on a segregated flow of the components is described. Mathematical modeling is used to analyze the physical mechanism of smoothing fluctuations of microcomponent dosage portions in a continuous granular materials mixer having a rotating drum. The influence of design and operating parameters of the apparatus on the magnitude of fluctuation of concentration of batch-dosed components in the mixture is studied using an experimental relationship that determines the intensity of formation of a segregated flow in a drum apparatus for a mixture of model granular materials. [ABSTRACT FROM AUTHOR]

The new design of a fractional-order microwave differentiator is proposed. It is first of its kind and uses short-circuited stub and transmission line sections to emulate the behaviour of an ideal fractional-order differentiator. Least mean square errorbased objective function is formulated to obtain the transfer function of the proposed design, using the chain scattering parameters of line elements in the Z-domain. During the optimisation process, impedance values of equal-electrical-length line elements are considered in the range 10-150 Ω, such that they are practically realisable on the microstrip format. The structure is implemented on the FR4 substrate with permittivity of 4.4 having 1.6 mm thickness. The measured result for the magnitude response of the transmission coefficient is found to be in good agreement with ideal one in the operating frequency range from 0.8 to 6.6 GHz. [ABSTRACT FROM AUTHOR]

The results of development of the basic structure and technological conditions of growing heterostructures for single- and dual-frequency quantum-cascade lasers are reported. The heterostructure for a dual-frequency quantum-cascade laser includes cascades emitting at wavelengths of 9.6 and 7.6 μm. On the basis of the suggested heterostructure, it is possible to develop a quantum-cascade laser operating at a difference frequency of 8 THz. The heterostructures for the quantum-cascade laser are grown using molecularbeam epitaxy. The methods of X-ray diffraction and emission electron microscopy are used to study the structural properties of the fabricated heterostructures. Good agreement between the specified and realized thicknesses of the epitaxial layers and a high uniformity of the chemical composition and thicknesses of the epitaxial layers over the area of the heterostructure is demonstrated. A stripe-structured quantum-cascade laser is fabricated; its generation at a wavelength of 9.6 μm is demonstrated. [ABSTRACT FROM AUTHOR]

In modern gas turbine engines, the first stage vane endwall endures high thermal load with the increase of the turbine inlet temperature and the uniformity of the temperature distribution at combustor outlet. Moreover, the endwall secondary flow forces the coolant flow toward the suction side, resulting in hot regions along the pressure side endwall. In the worst case, hot regions lead to thermal failure. In order to ensure that the gas turbine operates safely, advanced cooling techniques are urgently needed to be implemented to reduce the hot regions along the pressure side endwall. In the current research, the influences of the pressure side injection slot on the film cooling performance of the endwall surface were numerically investigated. The three-dimensional Reynolds-averaged Navier-Stokes (RANS) equations combined with the shear stress transport (SST) turbulence model were solved to conduct the simulations. Cases with different injection slot configurations have been simulated. The results indicate that the hot region along the pressure side endwall is significantly reduced by introducing the pressure side injection slot. The coolant from the pressure side injection slot is assisted by the pressure side vertical flow toward the adjacent vane suction side. Therefore, the coolant coverage and the cooling effectiveness are increased. In this study, the expanded slot (ES) achieves a larger cooling effectiveness than the normal slot (NS) and convergent slot (CS) at a small blowing ratio M = 0.5. In contrast, the CS obtains a larger cooling effectiveness than the NS and ES at M = 1.0 and M = 1.5. In addition, the introduction of the pressure side injection slot has a small influence on the aerodynamic performance of the vane cascade. [ABSTRACT FROM AUTHOR]

High mortality among adolescents with HIV reflects delays and failures in the care cascade. We sought to elucidate critical missed opportunities and barriers to care among adolescents hospitalized with HIV at Botswana’s tertiary referral hospital. We enrolled all HIV-infected adolescents (aged 10–19 years) hospitalized with any diagnosis other than pregnancy from July 2015 to January 2016. Medical records were reviewed for clinical variables and past engagement in care. Semi-structured interviews of the adolescents (when feasible) and their caregivers explored delays and barriers to care. Twenty-one eligible adolescents were identified and 15 were enrolled. All but one were WHO Clinical Stage 3 or 4. Barriers to diagnosis included lack of awareness about perinatal HIV infection, illness or death of the mother, and fear of discrimination. Barriers to adherence to antiretroviral therapy included nondisclosure, isolation, and mental health concerns. The number of hospitalized HIV-infected adolescents was lower than expected. However, among those hospitalized, the lack of timely diagnosis and subsequent gaps in the care cascade elucidated opportunities to improve outcomes and quality of life for this vulnerable group. [ABSTRACT FROM AUTHOR]

DC–DC cascaded systems are vulnerable to instability and dynamic performance deterioration. These problems arise due to the nonideality in the source converter output impedance and to the negative input impedance of the load converter. Any overlap in magnitude between these two impedances will destabilize the voltage at the dc bus. Thus, we introduce a method to diminish the magnitude of source-converter output impedance such that the source converter will act as an ideal voltage source. As a consequence, the dynamic performance of the source and load converters will be intact, leading to ensuring the bus voltage stability. In addition, the controller is independent of the number of converters that form the load subsystem. To validate the proposed method, an experimental cascaded system was analyzed, simulated, and experimentally tested. Collectively, all of the outcomes proved the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

Decades of research indicate mitochondria from Alzheimer's disease (AD) patients differ from those of non-AD individuals. Initial studies revealed structural differences, and subsequent studies showed functional deficits. Observations of structure and function changes prompted investigators to consider the consequences, significance, and causes of AD-related mitochondrial dysfunction. Currently, extensive research argues mitochondria may mediate, drive, or contribute to a variety of AD pathologies. The perceived significance of these mitochondrial changes continues to grow, and many currently believe AD mitochondrial dysfunction represents a reasonable therapeutic target. Debate continues over the origin of AD mitochondrial changes. Some argue amyloid-β (Aβ) induces AD mitochondrial dysfunction, a view that does not challenge the amyloid cascade hypothesis and that may in fact help explain that hypothesis. Alternatively, data indicate mitochondrial dysfunction exists independent of Aβ, potentially lies upstream of Aβ deposition, and suggest a primary mitochondrial cascade hypothesis that assumes mitochondrial pathology hierarchically supersedes Aβ pathology. Mitochondria, therefore, appear at least to mediate or possibly even initiate pathologic molecular cascades in AD. This review considers studies and data that inform this area of AD research. [ABSTRACT FROM AUTHOR]

A methodology for the synthesis of 2H-[1,3]oxazino[ 3,2-α]indolin-4(3H)-ones is reported. They are obtained from readily available materials by a facile synthetic procedure following either a two-step cascade reaction or a step-by-step transformation. The target compounds represent a hitherto unreported class of indole derivatives with a novel kind of tris- or tetracyclic backbone. [ABSTRACT FROM AUTHOR]

Abstract: A one‐pot two‐step enzymatic strategy has been designed for the production of optically active γ‐ and δ‐lactams in aqueous medium under mild conditions. The approach is based on the biotransamination of ethyl or methyl keto esters bearing different alkyl or aryl substitution patterns at α‐position to the ketone functionality. In this manner, the keto esters were transformed into the corresponding amino esters with excellent conversions, which underwent spontaneous cyclisation in the reaction medium without addition of external reagents. Depending on the transaminase selectivity, both lactam enantiomers can be obtained, so initial enzyme screenings were performed using commercially available and made in house enzymes. Reaction conditions were optimised focusing on the substrate concentration, temperature and ratio of amine donor vs acceptor. Thus, ten γ‐ and δ‐lactams were obtained in good to high isolated yields (70–90%) and excellent selectivities (94–99%) after one or two days at 30 or 45 °C. [ABSTRACT FROM AUTHOR]

Impacts from floods in urban areas can be diverse and wide ranging. These can include the loss of human life, infrastructure and property damages, as well as other kinds of nuisance and inconvenience to urban life. Hence, the ability to identify and quantify wider ranging effects from floods is of the utmost importance to urban flood managers and infrastructure operators. The present work provides a contribution in this direction and describes a methodological framework for analysing cascading effects from floods that has been applied for the Sukhumvit area in Bangkok (Thailand). It demonstrates that the effects from floods can be much broader in their reach and magnitude than the sole impacts incurred from direct and immediate losses. In Sukhumvit, these include loss of critical services, assets and goods, traffic congestion and delays in transportation, loss of business and income, disturbances and discomfort to the residents, and all these can be traced with the careful analysis of cascading effects. The present work explored the use of different visualization options to present the findings. These include a casual loop diagram, a HAZUR resilience map, a tree diagram and GIS maps. [ABSTRACT FROM AUTHOR]

The Q-cascade is a type of model cascade that is particularly useful for studying multicomponent isotope separation. The cascade segmentation technique is further developed to optimize Q-cascades, which minimizes the relative total flow by splitting a cascade into smaller segments that each use the mass number of the virtual component as a decision variable. Application of this technique to Cadmium isotope separation shows that it is always effective. If the number of segments into which a cascade is split increases, then the minimum relative total flow decreases. A progressive segmentation strategy is developed to maximize the number of segments. [ABSTRACT FROM PUBLISHER]