Abstract
We investigated expression profiles of microRNA (miRNA) in gastric carcinomas by use of a miRNA microarray platform covering a total of 470 human miRNAs. We identified 39 differentially ...expressed miRNAs in gastric carcinoma, of which six were significantly downregulated and the other 33 were upregulated. We found that miRNA-375 (miR-375) was the most downregulated and that its ectopic expression in gastric carcinoma cells markedly reduced cell viability via the caspase-mediated apoptosis pathway. Interestingly, we found that expression of miR-375 inhibited expression of PDK1, which is a direct target of miR-375, followed by suppression of Akt phosphorylation. Further analysis by gene expression microarray revealed that 14-3-3ζ, a potent antiapoptotic gene, was significantly downregulated at both the mRNA and protein levels in cells transfected with miR-375. The activity of a luciferase reporter containing the miR-375 binding sequence at the 3′ untranslated region (UTR) of 14-3-3ζ mRNA was repressed by the ectopic expression of miR-375, suggesting that miR-375 targets the 3′ UTR of 14-3-3ζ. In addition, knockdown of either PDK1 or 14-3-3ζ in gastric carcinoma cells induced caspase activation, which was also observed in miR-375–transfected cells, suggesting that miR-375 may exert its proapoptotic function, at least in part, through the downregulation of PDK1 and 14-3-3ζ. Taken together, we propose that miR-375 is a candidate tumor suppressor miRNA in gastric carcinoma. Cancer Res; 70(6); 2339–49
•n-Butanol does not affect vapour spray penetration even with 60% in volume.•The increase of n-butanol amount decreases drastically the mixture reactivity, so delays the combustion.•Butanol/gasoline ...blend is able to produce higher efficiency than gasoline fuel under partially premixed combustion mode.
As bio-butanol would be one promising alternative fuel to mitigate the energy crisis and reduce the environmental impact of the automotive sector, its potential as blend in gasoline has been widely evaluated especially for conventional Spark Ignition engines. But recent studies prove that Gasoline Compression Ignition operating mode could be a future interesting advanced combustion mode to reach higher efficiency and lower pollutant emissions than conventional SI engines. The objective of this paper is to underline the effect of butanol blend in gasoline in injections conditions needed in GCI by set experimental study in a High Pressure/ High Temperature chamber. Therefore, first data about sprays and combustion characteristics as a function of the butanol content in a gasoline surrogate (PRF80) at injection conditions of GCI, i.e. high pressure (6 MPa) and high-temperature (900 K) conditions but with injection pressure of 40 MPa are given and he results discussed thanks to kinetics simulation of ignition delays.
•A discrete dynamic modeling of a ball screw drive system for investigating the relationship between preload level and axial natural frequency of the ball screw system is proposed.•Preload level can ...be estimated from the axial natural frequency of the ball screw system and the current working table displacement.•Signal processing method for measuring the real time preload level of ball screw drive system in operational mode is proposed.•Three ranges of preload level (high, normal, low preload) are effectively and intuitively monitored during operational mode.•(Revision) An impact test results was added to verify predicted natural frequency of axial mode of table.
In this paper, we propose a method to monitor the preload of an operational ball screw drive system mostly used in CNC machine tools by evaluating the natural frequency of the screw nut in the axial direction and the corresponding working table displacement. First, we derived a discrete dynamic model and used it to study the variation in the ball screw system preload. Second, we proposed a method for monitoring the ball screw preload in operational mode via the motor current signal and the screw nut axial vibration signal. We apply this method by acquiring and analyzing the signals from the system as it undergoes a transition in its motion, then compose the frequency response function (FRF) of the ball screw system. This enables us to detect the axial natural frequency of the ball screw drive system. The ball screw preload is then calculated and monitored as the system is operational. We provide an efficient and intuitive method to monitor the variation in preload level of an operational ball screw system. This method can be used as an indicator of the health status of the drive system in particular, as well as for the entire machine tool in general.
The invariable site plus Γ model (I+Γ) is widely used to model rate heterogeneity among alignment sites in maximum likelihood and Bayesian phylogenetic analyses. The proof that the I+ continuous Γ ...model is identifiable (model parameters can be inferred correctly given enough data) has increased the creditability of its application to phylogeny reconstruction. However, most phylogenetic software implement the I+ discrete Γ model, whose identifiability is likely but unproven. How well the parameters of the I+ discrete Γ model are estimated is still disputed. Especially the correlation between the fraction of invariable sites and the fractions of sites with a slow evolutionary rate is discussed as being problematic. We show that optimization heuristics as implemented in frequently used phylogenetic software (PhyML, RAxML, IQ-TREE, and MrBayes) cannot always reliably estimate the shape parameter, the proportion of invariable sites, and the tree length. Here, we propose an improved optimization heuristic that accurately estimates the three parameters. While research efforts mainly focus on tree search methods, our results signify the equal importance of verifying and developing effective estimation methods for complex models of sequence evolution.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NMLJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
•Different ABE-Butanol/dodecane blends are studied in ECN spray A conditions.•Ignition delays, lift-off lengths and soot emissions are experimentally investigated.•Impacts of oxygen content in fuel ...are revealed.•20% of ABE or Butanol can be used as fuel without any major engine modification.
This study investigates the feasibility of using Acetone-Butanol-Ethanol mixture (ABE) as a function of the volumetric ratios (20 %v, 30 %v, 40 %v, 50 %v blended with n-dodecane) in order to determine the most suitable ABE ratio for CI engines in comparison to a butanol/n-dodecane blend. The “New One Shot Engine” set-up was used to determine the lift-off length (LOL), ignition delay (ID) and soot concentration by means of OH* chemiluminescence and Diffused Back Illumination imaging at an ambient pressure and temperature of 60 bar and 900 K corresponding to ECN Spray-A conditions. It was found that ID and LOL increased, while soot concentration was reduced with the increase in concentration of ABE and Butanol in dodecane blends. The blends with the smallest content (20%) of ABE or Bu exhibited similar combustion characteristics to n-dodecane with a considerable reduction in soot, indicating that these blends can be considered as a Diesel substitute without any engine modifications.
Internet-of-Things concepts are evolving the power systems to the Energy Internet paradigm. Microgrids (MGs), as the basic element in an Energy Internet, are expected to be controlled in a ...cooperative and flexible manner. This article proposes a novel distributed control scheme for multiagent systems (MASs) governed MGs in future Energy Internet. The control objectives are frequency/voltage restoration and proportional power sharing. The proposed control scheme considers both intra- and inter-MASs interactions, which offers group plug-and-play capability of distributed generators. The stability and communication delay issues in the control framework are analysed. A multisite implementation framework is presented to explain the agent architecture as well as data exchange in local area networks and the cloud server. Then a cyber hardware-in-the-loop experiment is conducted to validate the proposed control method with multisite implementation. The experimental results prove the effectiveness and application potentials of the proposed approach.
This paper introduces a comprehensive motion planning–tracking–safety constraint scheme for a 3D ballbot system. A nonlinear control for the 3D ballbot system is designed based on three separate ...planes by utilizing extended state observer (ESO) to estimate coupling mechanisms. Three virtual control signals are generated from these distinct planes and can be used for formulating actual control signals. To overcome the complexity of nonlinear motion equations, flatness theory is used to construct the time‐optimal trajectory through an optimization problem, facilitating smooth movement of the ballbot, and obstacle avoidance based on RRT* waypoints. Furthermore, our work manipulates the hierarchical sliding mode controller (HSMC) as the nominal controller to ensure that the ballbot tracks to the optimal trajectory, unifying with the exponential control barrier function (ECBF) to address safety constraints in the body's deflection angle. Through extensive simulations and comparative analysis, the system demonstrates its effectiveness and safe operation in various working conditions.
Distributed control and optimization strategies are a promising alternative approach to centralized control within microgrids. In this paper, a multi-agent system is developed to deal with the ...distributed secondary control of islanded microgrids. Two main challenges are identified in the coordination of a microgrid: (i) interoperability among equipment from different vendors; and (ii) online re-configuration of the network in the case of alteration of topology. To cope with these challenges, the agents are designed to communicate with physical devices via the industrial standard IEC 61850 and incorporate a plug and play feature. This allows interoperability within a microgrid at agent layer as well as allows for online re-configuration upon topology alteration. A test case of distributed frequency control of islanded microgrid with various scenarios was conducted to validate the operation of proposed approach under controller and power hardware-in-the-loop environment, comprising prototypical hardware agent systems and realistic communications network.
Organisms use endogenous clocks to anticipate regular environmental cycles, such as days and tides. Natural variants resulting in differently timed behaviour or physiology, known as chronotypes in ...humans, have not been well characterized at the molecular level. We sequenced the genome of Clunio marinus, a marine midge whose reproduction is timed by circadian and circalunar clocks. Midges from different locations show strain-specific genetic timing adaptations. We examined genetic variation in five C. marinus strains from different locations and mapped quantitative trait loci for circalunar and circadian chronotypes. The region most strongly associated with circadian chronotypes generates strain-specific differences in the abundance of calcium/calmodulin-dependent kinase II.1 (CaMKII.1) splice variants. As equivalent variants were shown to alter CaMKII activity in Drosophila melanogaster, and C. marinus (Cma)-CaMKII.1 increases the transcriptional activity of the dimer of the circadian proteins Cma-CLOCK and Cma-CYCLE, we suggest that modulation of alternative splicing is a mechanism for natural adaptation in circadian timing.
•A distributed control scheme for heterogeneous energy storage systems.•First-order and second-order finite-time consensus algorithm with stability proof.•Achieve finite-time state-of-charge ...balancing, voltage and frequency restoration.•Cyber-physical perspective of microgrid controller design.•Validation of the proposed method in a hardware-in-the-loop microgrid platform.
Microgrid (MG) is evolving towards a complex interacted cyber-physical system. In the physical layer, the energy storage systems (ESSs) are installed to mitigate the uncertainty of renewables. In the cyber layer, the distributed algorithms implemented on multi-agent systems are widely proposed to enhance system resilience and flexibility. Therefore, in this paper, a distributed control framework with the finite-time approach and cyber-physical implementation is proposed for ESSs with heterogeneous parameters in islanded MGs. With the proposed control framework, the fair power sharing and state-of-charge balancing among ESSs can be accomplished in finite-time. In the meantime, the MG secondary control objective of frequency and voltage restoration is also achieved. The stability of the proposed controllers is proved via the Lyapunov method. Towards the practical application, the MG entities and primary controllers, as the physical system, are emulated in OPAL-RT, while the distributed finite-time algorithms and multi-agent system, as the cyber system, are realized in multiple Raspberry Pis. The cyber hardware-in-the-loop experiment results demonstrate the effectiveness of the proposed controller design under various scenarios.
PDF
