Step Of Loop Research Articles

A Two-Pronged Delivery Strategy Disrupting Positive Feedback Loop of Neutrophil Extracellular Traps for Metastasis Suppression.

Neutrophil extracellular traps (NETs) severely affect tumor metastasis through a self-perpetuating feedback loop involving two key steps: (1) mitochondrial aerobic respiration-induced hypoxia promotes NET formation and (2) NETs enhance mitochondrial metabolism to exacerbate hypoxia. Herein, we propose a two-pronged approach with the activity of NET-degrading and mitochondrion-damaging by simultaneously targeting drugs to NETs and tumor mitochondria of this loop. In addition to specifically recognizing and eliminating extant NETs, the NET-targeting nanoparticle also reduces NET-induced mitochondrial biogenesis, thus inhibiting the initial step of the feedback loop and mitigating extant NETs' impact on tumor metastasis. Simultaneously, the mitochondrion-targeting system intercepts mitochondrial metabolism and alleviates tumor hypoxia, inhibiting neutrophil infiltration and subsequent NET formation, which reduces the source of NETs and disrupts another step of the self-amplifying feedback loop. Together, the combination significantly reduces the formation of NET-tumor cell clusters by disrupting the interaction between NETs and tumor mitochondria, thereby impeding the metastatic cascade including tumor invasion, hematogenous spread, and distant colonization. This work represents an innovative attempt to disrupt the feedback loop in tumor metastasis, offering a promising therapeutic approach restraining NET-assisted metastasis.

Preliminary results of the integrated hydrolysis reactor in the Cu-Cl hydrogen production cycle

This paper presents preliminary results of an integrated hydrolysis reactor at the Clean Energy Research Laboratory (CERL), University of Ontario Institute of Technology. Initial tests have demonstrated a successful reactor design allowing for effective recovery of liquid products. Using our best available performance metrics, the conversion rate of reagents to products ranged from 7% to 10%. Initial experimental runs demonstrated that the reactor was successfully operational with combined H2O and reagent injection in a configuration suitable for integration with the electrolysis step of the Copper-Chlorine loop. In this paper, we discuss the updated hydrolysis reactor design and present data from a number of recent experiments in which our research team recovered solids and chemical products not previously collected in prior studies. Comparisons were made with earlier XRD data taken at the Argonne National Laboratory. The comparisons showed promising results in the chemical composition of the solids produced. We conclude this paper with a discussion of future experiments to increase the conversion rate of reaction based on the observed trends.

Case study on optimization scheme design based on load prediction for regional heating system in industrial community

With the promotion of the electrical energy substitution, the electric heating in a larger scale tends to aggravate the peak load of grid. Such challenges could be solved by regenerative electric boiler, due to its advantages of transferring electric load to the valley. Furthermore, it is feasible to reduce the cost by combining the heat pumps and regenerative electric boilers. In order to obtain the optimization scheme of such integrated system, firstly, the heating load prediction model for an industrial community was established based on artificial neural network, and then, a fast-solving method was developed for engineering practice in this case study faced to operation optimization of regional heating system, by converting the multi-stage dynamic programming problem into linear programming problem. The time step of calculation loop is set as one-hour, and the start-stop signal of equipment could be obtained for the next 24 hours no more than one minute. A trade-off between calculation cost and accuracy can be achieved through proposed method or model, with a rapid response in design for such industrial community.

Signature of exchange bias and magneto-electric coupling in BiFeO3/SrRuO3 heterostructure

The magnetic interaction between BiFeO3 and SrRuO3 layers in a heterostructure grown on (001) oriented SrTiO3 substrate is investigated. A two-step magnetization reversal was observed in M−H hysteresis loop measurement of the heterostructure at 10K. The first step in the hysteresis loop is associated with the switching of the free SrRuO3 moments whereas the second step arises from the switching of the pinned moments. The total amount of the pinned SrRuO3 moment was observed to decrease with increasing thickness of the BiFeO3 layer. The presence of exchange bias effect in the heterostructure was confirmed by the field cooled M−H measurements where only the second step of hysteresis loop was observed to shift along the field axis. The coercivity of the second step of hysteresis loop decreases with increasing temperature and merges with that of the first step above 100K which infers the desertion of the pinned magnetic moments. Temperature dependent capacitance measurement shows a kink at the ferromagnetic transition temperature of SrRuO3 and a pronounced dip was observed in the second derivative of capacitance with respect to temperature, indicating a strong magneto-electric coupling between the two layers.

Type-III closed loop control systems-Digital PID controller design

The problem of tuning digital PID controllers for type-III control loops is investigated in this work. Type-III control loops are capable of achieving perfect tracking of step, ramp and parabolic reference signals with zero steady state position, velocity and acceleration error. The proposed PID control law involves any dominant time constants of the process itself, and any parasitic dynamics introduced by both the process and the controller, i.e. time delays within the closed control system. The development of the proposed control law takes place in the frequency domain and basis of the theory is the principle of the Magnitude Optimum criterion. The final control law consists of closed form expressions which involve also the controller's sampling time Ts. The potential of the proposed theory is justified for the control of several benchmark process models throughout simulation examples. The affect of the choice of the controller's sampling time is investigated further to the step and frequency response of the control loop both for the output of the control loop and the controller's command signal.

Convergence of adaptive FEM for some elliptic obstacle problem

In this work, we treat the convergence of adaptive lowest-order FEM for some elliptic obstacle problem with affine obstacle. For error estimation, we use a residual error estimator from [D. Braess, C. Carstensen, and R. Hoppe, Convergence analysis of a conforming adaptive finite element method for an obstacle problem, Numer. Math. 107 (2007), pp. 455–471]. We extend recent ideas from [J. Cascon, C. Kreuzer, R. Nochetto, and K. Siebert, Quasi-optimal convergence rate for an adaptive finite element method, SIAM J. Numer. Anal. 46 (2008), pp. 2524–2550] for the unrestricted variational problem to overcome the lack of Galerkin orthogonality. The main result states that an appropriately weighted sum of energy error, edge residuals and data oscillations satisfies a contraction property within each step of the adaptive feedback loop. This result is superior to a prior result from Braess et al. (2007) in two ways: first, it is unnecessary to control the decay of the data oscillations explicitly; second, our analysis avoids the use of some discrete local efficiency estimate so that the local mesh-refinement is fairly arbitrary.

Design and micromagnetic simulation of the L1-FePt/Fe multilayer graded film

The magnetic properties of the L10-FePt20 nm/Fe5 nm exchange spring bilayer were investigated using the micromagnetic simulation software object oriented micromagnetic framework (OOMMF). The results indicate that coercivity increases and thermal stability improves as the magnetocrystalline anisotropy constant (KFePt) of the L10-FePt hard layer increases. When KFePt reaches the critical value of 2.8 × 106 J/m3, an additional step appears in the hysteresis loop, and the magnetization process shows a two-phase reversal behavior, which is disadvantageous for practical applications of the recording media. However, setting KFePt as a graded variation removes the step of the hysteresis loop and reduces coercivity while allowing the thermal stability of the system to remain constant. These results can serve as a significant basis for the experimental preparation of exchange-coupled graded media.

An Alternative Approach to Identifying and Appraising Adaptive Loops in Complex Organizations

This paper describes a research into the adaptation property of complex organizations. The research is focused on the development of a methodology for identifying and appraising loops that can allow for organizational adaptation. The proposed methodology draws a parallel between the nature of adaptation in complex organizations and the process of adaptive decision- making in human behavior. From this perspective, the adaptive loop in complex organizations can be divided into four steps adapted from the OODA loop (Observe-Orient-Decide-Act). The extension of the OODA loop to an organizational scale is incorporated with an assumption that flow of information, involved in adaptation processes, can be formed by different organizational components. Subsequently, the OODA loop can be presented as a chain of actions created by independent components of both the organization and its environment. Applying this approach to complex organizations necessitates mapping a functional definition of different organizational components within each step of the adaptive loop. Thus, while the functional definition of an organization can be done by using existing tools of organizational analysis (organizational structure, functional decomposition, architecture frameworks, etc.), the main goal of this proposed methodology is the determination of adaptive loops on an organizational scale.

CREB and ChREBP oppositely regulate SIRT1 expression in response to energy availability.

The nicotinamide adenine dinucleotide (NAD(+))-dependent deacetylase SIRT1 is a major metabolic regulator activated by energy stresses such as fasting or calorie restriction. SIRT1 activation during fasting not only relies on the increase in the NAD(+)/NADH ratio caused by energy deprivation but also involves an upregulation of SIRT1 mRNA and protein levels in various metabolic tissues. We demonstrate that SIRT1 expression is controlled systemically by the activation of the cyclic AMP response-element-binding protein upon low nutrient availability. Conversely, in the absence of energetic stress, the carbohydrate response-element-binding protein represses the expression of SIRT1. Altogether, these results demonstrate that SIRT1 expression is tightly controlled at the transcriptional level by nutrient availability and further underscore that SIRT1 is a crucial metabolic checkpoint connecting the energetic status with transcriptional programmes.

Optimum Design of the Power Yacht Based on Micro-Genetic Algorithm

The optimum design of power yacht belongs to the nonlinear constrained optimization problems. The determination of scantlings for the bow structure is a very important issue with in the whole structural design process. The derived design results are obtained by the use of real-coded micro-genetic algorithm including evaluation from Lloyd's Register small craft guideline, so that the nominal limiting stress requirement can be satisfied. In this study, the minimum volume design of bow structure on the power yacht was carried out based on the finite element analysis. The target model for optimum design and local structural analysis is the bow structure of a power yacht. The volume of bow structure and the main dimensions of structural members are chosen as an objective function and design variable, respectively. During optimization procedure, finite element analysis was performed to determine the constraint parameters at each iteration step of the optimization loop. optimization results were compared with a pre-existing design and it was possible to reduce approximately 19 percents of the total steel volume of bow structure from the previous design for the power yacht.

Optimum design and local structural analysis of the power yacht based on micro-genetic algorithm

The optimum design of bow structure of power yacht belongs to the non-linear constrained optimisation problems. The determination of scantlings for the bow structure is a very important issue within the whole structural design process. The derived design results are obtained by the use of real-coded micro-genetic algorithm including evaluation from Lloyd's Register small craft guideline, so that the nominal limiting stress requirement can be satisfied. In this study, the minimum volume design of bow structure on the power yacht was carried out based on the finite element analysis. The target model for optimum design and local structural analysis is the bow structure of a power yacht. The volume of bow structure and the main dimensions of structural members are chosen as an objective function and design variable, respectively. During optimisation procedure, finite element analysis was performed to determine the constraint parameters at each iteration step of the optimisation loop. Optimisation results were compared with a pre-existing design and it was possible to reduce approximately 19% of the total steel volume of bow structure from the previous design for the power yacht.

Mechanisms of Catalyst Poisoning in Palladium-Catalyzed Cyanation of Haloarenes. Remarkably Facile C−N Bond Activation in the [(Ph3P)4Pd]/[Bu4N]+ CN- System

Reaction paths leading to palladium catalyst deactivation during cyanation of haloarenes (eq 1) have been identified and studied. Each key step of the catalytic loop (Scheme 1) can be disrupted by excess cyanide, including ArX oxidative addition, X/CN exchange, and ArCN reductive elimination. The catalytic reaction is terminated via the facile formation of inactive [(CN)4Pd]2-, [(CN)3PdH]2-, and [(CN)3PdAr]2-. Moisture is particularly harmful to the catalysis because of facile CN- hydrolysis to HCN that is highly reactive toward Pd(0). Depending on conditions, the reaction of [(Ph3P)4Pd] with HCN in the presence of extra CN- can give rise to [(CN)4Pd]2- and/or the remarkably stable new hydride [(CN)3PdH]2- (NMR, X-ray). The X/CN exchange and reductive elimination steps are vulnerable to excess CN- because of facile phosphine displacement leading to stable [(CN)3PdAr]2- that can undergo ArCN reductive elimination only in the absence of extra CN-. When a quaternary ammonium cation such as [Bu4N]+ is used as a phase-transfer agent for the cyanation reaction, C-N bond cleavage in the cation can occur via two different processes. In the presence of trace water, CN- hydrolysis yields HCN that reacts with Pd(0) to give [(CN)3PdH]2-. This also releases highly active OH- that causes Hofmann elimination of [Bu4N]+ to give Bu3N, 1-butene, and water. This decomposition mode is therefore catalytic in H2O. Under anhydrous conditions, the formation of a new species, [(CN)3PdBu]2-, is observed, and experimental studies suggest that electron-rich mixed cyano phosphine Pd(0) species are responsible for this unusual reaction. A combination of experimental (kinetics, labeling) and computational studies demonstrate that in this case C-N activation occurs via an S(N)2-type displacement of amine and rule out alternative 3-center C-N oxidative addition or Hofmann elimination processes.

SIMPLIFIED COPPER PRODUCTION FROM PRIMARY CONCENTRATES: THE DIRECT ELECTROREFINING OF WHITE METAL/COPPER MATTE

Commercial copper plants utilizing current best technology are tending towards an ever increasing scale in which the concentrate requirements cannot be serviced by a single mine. In such cases, raw materials are often sourced from different mines which are often far away from the production plant and usually with very different ore compositions. These plants tend to use the traditional thermal processing steps of smelting, converting to blister, anode refining and casting to produce copper anodes that are then refined in a sulphate electrorefining operation. These thermal steps are in some cases troublesome and require the recycling of considerable quantities of material. A new process was developed taking advantage of the latest developments of the first thermal step of the classic loop, the smelting of copper concentrate to high grade matte or white metal using the well-known Ausmelt® Top Submerged Lancing (TSL) technology. The white metal and/or high grade matte product is converted directly to copper cathode and elemental sulphur using the ECUPREX™ technology. This approach provides an alternative to the traditional thermal steps of conversion to blister, thermal refining and anode casting, which, especially on a small scale, can be expensive and problematic in terms of technical and environmental concerns. At first evaluation, this new process can be operated at low capacities, thereby changing the traditional approach to copper production. Instead of taking the concentrate to the copper production plant, the copper production plant is built closer to the mine with some significant economic and technical advantages.Les usines commerciales de cuivre utilisant la meilleure technologie en cours tendent vers une toujours plus grande échelle où une seule mine ne peut pas satisfaire à la demande en concentré. Dans de tels cas, on obtient souvent les matériaux bruts à partir de plusieurs mines qui sont souvent fort éloignées de l’usine de production et ayant habituellement des compositions bien différentes de minerai. Ces usines tendent à utiliser les étapes traditionnelles de traitement thermique de fusion, conversion en brut, raffinage de l’anode et moulage pour produire des anodes de cuivre qui sont ensuite raffinées dans une opération d’électroaffinage de sulfate. Dans certains cas, ces étapes thermiques sont problématiques et nécessitent le recyclage de grandes quantités de matériaux. On a développé un nouveau procédé qui prend avantage des derniers développements de la première étape thermique de la boucle classique, la fusion du concentré de cuivre en une matte de haute qualité ou métal blanc utilisant la technologie bien connue d’Ausmelt® Top Submerged Lancing (TSL). Le produit de métal blanc et/ou de matte de haute qualité est converti directement en cathode de cuivre et soufre élémentaire en utilisant la technologie ECUPREX™. Cette approche fournit un choix aux étapes thermiques traditionnelles de conversion en brut, de raffinage thermique et de moulage d’anode qui, particulièrement à petite échelle, peuvent être dispendieuses et problématiques sur le plan technique et environnemental. À partir d’une première évaluation, on peut faire fonctionner ce nouveau procédé à faible capacité, changeant par là l’approche traditionnelle de la production du cuivre. Au lieu d’apporter le concentré à l’usine de production du cuivre, on construit l’usine de production de cuivre plus près de la mine avec d’importants avantages économiques et techniques.

Knowledge Reuse and Transfer in a Project Management Environment

This paper analyzes how project management companies manage knowledge. The research focuses on the creation, transfer, reuse and management of that knowledge. We propose a model for knowledge reuse in a project management environment where knowledge is absorbed at a tactical level and flows to a strategic level. This model derives from the: the OODA loop - Observe, Orient, Decide, Act, which focuses on strategic requirements and the Plan Do Study Act (PDSA) cycle, which focuses on the operational or tactical level of projects. Both the OODA Loop and the PDSA Cycle are adaptive learning and decision- making cycles where changes or actions are produced via repeated cycling through that loop. We suggest the ’Act’ step of the PDSA cycle is similar to the ’Orient’ step of the OODA loop because changes or learning is occurring. In this instance the PDSA cycle is renamed the PDSO (Plan-Do-Study-Orient) cycle. Research results indicate that knowledge flows between projects at all steps of (the PDSO Cycle) and OODA Loop. Key findings include a preference for informal over formal networks, the lack of a knowledge management system and the link between knowledge processes and the corporate project methodology. However, an effective knowledge management strategy also requires a strategic fit between social networks, technology, processes and corporate culture.

A cyclical but asynchronous pattern of fine root and woody biomass production in a hardwood forest of southern Quebec and its relationships with annual variation of temperature and nutrient availability

In contrast to the well-documented seasonal variation in growth of below- and above-ground components of trees, the annual variation in below- and aboveground production is not well understood. In this study, we report on the monitoring of an unmanaged hardwood forest ecosystem in a small watershed of southern Quebec between 1993 and 1999. Below- and above-ground biomass production, leaf and soil solution chemistry, and air temperature were measured at different regular intervals and are reported on an annual basis. The objective of the study was to describe the annual dynamics of carbon partitioning between below- and above-ground tree components and to gain a better understanding of the soil and climatic factors that govern it. Fine root production peaked one year earlier than woody biomass production and years with high production of fine roots had low woody biomass production. All models that included May temperature in the calculation of the predicting/independent variables were significant predictors of total tree biomass production (r > 0.87). Fine root production was associated negatively with the previous year average growing season temperature (r < -0.84). Soil solution NO3 −, NH4 + and NO3 − + NH4 + concentrations were positively correlated with fine root production (r > 0.72) and negatively correlated with woody biomass production (r < -0.84). Leaf N and P concentrations were negatively correlated (r = -0.99 and r = -0.98, respectively) with fine root production for the period of 1994–1998. Our results suggest that a cool growing season, and in particular a cool month of October, is likely to result in low fine root production and nutrient uptake the following year and, therefore, to increase soil N availability and decrease leaf N. This initial response is thought to be the first step of a feedback loop involving plant N nutrition, soil N availability, fine root growth and aboveground biomass production that led to a cyclical (3–4 years) but asynchronous production of fine roots and aboveground biomass production.

An equivalent continuously differentiable model and a locally convergent algorithm for the continuous network design problem

The continuous network design problem (CNDP) is characterized by a bilevel programming model and recognized to be one of the most difficult and challenging problems in transportation. The main difficulty stems from the fact that the bilevel formulation for the CNDP is nonconvex and nondifferentiable, and indeed only some heuristic methods have been so far proposed. In this paper, the bilevel programming model for CNDPs is transferred into a single level optimization problem by virtue of a marginal function tool. By exploring the inherent nature of the CNDP, the marginal function for the lower-level user equilibrium problem is proved to be continuously differentiable and its functional value and derivative in link capacity enhancement can be obtained efficiently by implementing a user equilibrium assignment subroutine. Thus a continuously differentiable but still nonconvex optimization formulation of the CNDP is created and a locally convergent augmented Lagrangian method is applied to solve this equivalent problem. The descent direction in each step of the inner loop of the solution method can be found by doing an all or nothing assignment. These favorable characteristics indicate the potential of the algorithm to solve large CNDPs. Numerical examples are presented to compare the proposed method with some existing algorithms.

Participation of S-S loops in inhibitory activity of peanut protease inhibitor B-III.

A peanut Bowman-Birk (BBI) type protease inhibitors B-III has two regions, 1 and 2, homologous with each other. Each region contains three S-S loops and a reactive site in its outermost loop. The inhibitor was used to investigate the contribution of the S-S loops of BBI-type inhibitors to their inhibitory activity. Two steps of Edman degradation of the native inhibitor cleaved loop III (the innermost S-S loop) of region 1 of B-III, and the antichymotryptic activity of the first reactive site decreased to about 1/4 of that of native B-III. A third step of Edman degradation split loop II and the inhibitory activity at that site became extremely low (about 1/200 of the original value). These results suggest that protease inhibitor B-III maintains its active conformation by means of the three S-S loops and that the conformation is markedly changed by the splitting of loop II.