bluuebunny/crossref_metadata_2025_split huggingface dataset:
The impact of radiotherapy on facial nerve repair
Authors: Gidley Paul W. , Herrera Stephanie J. , Hanasono Matthew M. , Yu Peirong , Skoracki Roman , Roberts Dianna B. , Weber Randal S. 
Published: July 2010

AbstractObjective:To study the impact of radiotherapy on the success of primary facial nerve repair and cable nerve grafts.Study Design:Retrospective review.Methods:Pre‐ and postoperative facial nerve function were assessed using the House‐Brackmann (HB) grading system.Results:Thirty‐nine patients were identified who had undergone facial nerve repair: 5 patients (13%) underwent primary repair, and 34 patients (87%) underwent nerve grafting. Radiotherapy was administered postoperatively to 34 patients (87%). Preoperative HB scores were I = 18, II = 11, III = 3, IV = 3, V = 3, and VI = 1. Postoperative scores were HB I = 1, II = 4, III = 16, IV = 6, V = 3, and VI = 9. Only patients with single‐branch deficits recovered to HB I or II function. Good facial function (HB I–III) was achieved in 17 of 34 patients (50%) who received postoperative radiotherapy compared to 4 of 5 patients (80%) who did not receive postoperative radiotherapy (P = .349). Among the patients who had either HB I or II function preoperatively, 59% achieved good postoperative function (HB I–III). Four out of 10 patients (40%) with significantly compromised preoperative facial function (HB III–VI) were able to achieve HB III function.Conclusions:Postoperative radiotherapy appears not to prevent achieving good facial function after a nerve repair, especially when normal or near‐normal function is present preoperatively. Some patients with fair to little function preoperatively can achieve reasonable postoperative function with facial nerve reconstruction. Laryngoscope, 2010
Bilateral motion restored to the paralyzed canine larynx with implantable stimulator
Authors: Nomura Kenichiro , Kunibe Isamu , Katada Akihiro , Wright Charles T. , Huang Shan , Choksi Yash , Mainthia Rajshri , Billante Cheryl , Harabuchi Yasuaki , Zealear David L. 
Published: July 2010

AbstractObjectives/Hypothesis:Bilateral stimulation of posterior cricoarytenoid (PCA) muscles offers a physiologic approach to restore ventilation to a normal level in case of bilateral laryngeal paralysis. The objective of this study was to evaluate the long‐term efficacy and safety of a new generation stimulator in restoring ventilation and exercise tolerance.Study Design:A prospective study of four canines over 8–20 months.Methods:A Genesis XP stimulator and electrodes were implanted and recurrent laryngeal nerves were sectioned and repaired bilaterally. In bimonthly sessions, vocal fold movement resulted from PCA stimulation or induced hypercapnea, was measured endoscopically in the anesthetized animal. Exercise tolerance was measured on a treadmill and swallowing function was examined endoscopically and radiographically.Results:During the denervation phase, there was minimal ventilatory compromise and near‐normal exercise tolerance. PCA stimulation produced only nominal abduction. During the reinnervation phase, synkinetic reinnervation became significant, resulting in a narrowed passive airway and paradoxical glottic closure during hypercapnea. Animals were stridorous and could walk for only 1–2 minutes. Bilateral PCA stimulation increased glottal area, equaling that of a normally innervated animal. Exercise tolerance was also normal. The optimal stimulus paradigm for the synkinetically reinnervated larynx was not different from that for the innervated larynx. Stimulation remained efficacious over the study period. Lead integrity could be maintained by prevention of device migration. There was no evidence of aspiration.Conclusions:This study demonstrates that ventilatory compromise only occurs following faulty reinnervation. Bilateral PCA stimulation can restore ventilation and exercise tolerance completely without aspiration over the long term. Laryngoscope, 2010
RAFT‐Mediated Polymerization—A Story of Incompatible Data?
Authors: Klumperman Bert , van den Dungen Eric T. A. , Heuts Johan P. A. , Monteiro Michael J. 
Published: July 2010

AbstractThe mechanistic interpretation of kinetic anomalies in reversible addition–fragmentation chain transfer (RAFT)‐mediated polymerization is critically reviewed. The main conclusion of this exercise is that available data do not allow model discrimination between the two prevailing mechanistic schemes, i.e., the slow fragmentation model and the intermediate radical termination model. However, assessment of the rate parameters reveals that the incompatibilities may not be as large as previously reported in literature. Dedicated kinetic studies on model compounds should be performed to shed further light on the seemingly incompatible data that currently exists in literature.magnified image
Down‐regulation of MMP‐2 through the p38 MAPK‐NF‐κB‐dependent pathway by aloe‐emodin leads to inhibition of nasopharyngeal carcinoma cell invasion
Authors: Lin Meng‐Liang , Lu Yao‐Cheng , Chung Jing‐Gung , Wang Shyang‐Guang , Lin Hsin‐Ting , Kang Shang‐En , Tang Chih‐Hsin , Ko Jiunn‐Liang , Chen Shih‐Shun 
Published: July 2010

AbstractAloe‐emodin (AE), extracted from the rhizome of Rheum palmatum, has an anti‐proliferative effect on different human cancer cell lines. Nonetheless, the underlying mechanism by which AE inhibits nasopharyngeal carcinoma (NPC) cell invasion is still unclear. The results of this study show that treatment of NPC cells with growth suppressive concentrations of AE caused cell cycle arrest at the S‐G2/M phase. Coimmunoprecipitation and small interfering RNA (siRNA) studies demonstrated that AE‐induced cell cycle arrest in NPC cells was associated with increasing levels of cyclin B1 bound to cyclin‐dependent kinase 1. The inhibition of NPC cell invasion by AE was evidenced through the suppression of matrix metalloproteinases‐2 (MMP‐2) expression. MMP‐2 promoter activity and cell invasion were inhibited by p38 mitogen‐activated protein kinase (MAPK) siRNA, inhibitor 4‐(4‐Fluorophenyl)‐2‐[4‐(methylsulfinyl)phenyl]‐5‐(4‐pyridyl)‐1H‐imidazole (SB203580), and AE, but not by JNK siRNA and inhibitor 1,9‐pyrazoloanthrone. Treatment with AE, SB203580, NF‐κB inhibitors N‐p‐tosyl‐L‐phenylalanine chloromethyl ketone (TPCK) and pyrrolidine dithiocarbamate (PDTC) or transfection with p38 MAPK siRNA significantly inhibited NF‐κB transcriptional activity. In addition, TPCK and PDTC treatment inhibited the expression and promoter activity of MMP‐2 and thereby significantly inhibited cell invasion activity. The involvement of p38 MAPK activity in NF‐κB‐mediated MMP‐2 function was further confirmed through the attenuation of p38 MAPK by SB203580 and NF‐κB ectopic expression. Collectively, our results indicate that AE inhibits invasion of NPC cells by suppressing the expression of MMP‐2 via the p38 MAPK‐NF‐κB signaling pathway. © 2010 Wiley‐Liss, Inc.
Bei Reach und Co verschwimmen die Grenzen
Authors: Geldsetzer Felix O. 
Published: July 2010

AbstractDas europäische Chemikalienrecht bleibt uneinheitlich — auch nachdem Reach und GHS in Kraft getreten sind. Die jeweils geltende Regelung muss sich der Bürger aus vielen Vorschriften heraussuchen; dabei sind die Grenzen oft unscharf.
Analytical and numerical analyses of the load‐bearing capacity of retaining walls laterally supported at both ends
Authors: Plumey Sylvain , Muttoni Aurelio , Vulliet Laurent , Labiouse Vincent 
Published: July 2010

AbstractThis paper investigates the load‐bearing capacity of a perfectly smooth retaining wall laterally supported at both ends assuming that the wall fails by the development of three plastic hinges. The study considers the case of a cohesionless elastic–perfectly plastic backfill with a Mohr–Coulomb yield criterion and an associative flow rule in drained conditions. A kinematically admissible soil–structure failure mechanism is proposed and compared with the conventional solutions and with results from a numerical finite element modelling. The study shows that the proposed solution and the numerical solution are in good agreement. These solutions are found to be much more favourable for the wall than the conventional solutions. Copyright © 2010 John Wiley & Sons, Ltd.
Optimal exploration and consumption of a natural resource—deterministic case
Authors: Derzko N. A. , Sethi S. P. 
Published: July 2010

AbstractAn exploration and consumption model for exhaustible natural resources is used to formulate a deterministic optimal control problem over an infinite time horizon. A dynamic programming approach is employed throughout. The non‐linear partial differential equation which results from an application of the necessary conditions is solved analytically by the method of characteristics. Several properties of the solution are discussed.
Unloading of congestion in deterministic queueing networks
Authors: Filipiak Janusz 
Published: July 2010

AbstractThe purpose of this paper is to find a control procedure which would efficiently unload the congestion in a queueing network. The congestion phenomenon is described by a dynamic deterministic model. The total waiting time of all entities in the overloaded region is assumed to be a performance index. The Pontryagin maximum principle is applied to show that for the optimal flow pattern cycles cannot exist and all routes leading from the given node to the outside of the overloaded region have to have the same length. These two properties are the basis for a construction of the algorithm. A topological optimization algorithm is used, since the solution must be a tree. The existence and uniqueness of the optimal solution are investigated.
Optimal control of discrete time population processes
Authors: Haurie A. , Berger C. , Pelland S. 
Published: July 2010

AbstractThis paper deals with two classes of large‐scale Markov decision models which can be used, respectively, for hospital admission scheduling and multicomponent system maintenance. These models are called population processes as they describe a set of individuals represented by a set of independent replicas of the same underlying stochastic core process. Two examples are completely worked out, showing the potential utilization of this modelling approach.
Application of sensitivity methods to the problem of optimal control of hydro‐thermal power systems
Authors: Dillon T. S. , Tun T. 
Published: July 2010

AbstractThe sensitivity analysis approach is applied to the hydro‐thermal problem. Its use for rescheduling in the presence of load forecasting errors and inflow forecast errors is developed. Its use for identification of important parameters in the system is also shown. Application to two sample power systems permits some practical conclusions to be drawn for similar hydro‐thermal systems.
Optimal control applications in biomedical engineering—a survey
Authors: Swan George W. 
Published: July 2010

AbstractThe concept of a biological system operating in an optimal manner is intriguing. When this system (e.g. a human) is in a disease state, how can one administer appropriate optimal therapeutic treatment so that it can resume functioning with, hopefully, its original undiseased attributes? Biomedical engineering has a significant role to play in this area. This article illustrates some of the current attempts at improving therapy and the biomedical understanding of a normal or a disease state by using methods of optimal control theory such as the Pontryagin minimum principle, dynamic programming, and the calculus of variations.
Optimal design of damped dynamic structures
Authors: Kimf Seung Woo , Kwak Byung Man 
Published: July 2010

AbstractA method of optimal design of damped structures under dynamic loads is developed, and several illustrative problems for minimum‐weight design of planar frame structures under impulsive external forces or ground accelerations are studied. In order to analyse dynamic structures, the finite element method and modal analysis technique are used, and structural damping is included in terms of modal damping ratios. For numerical optimization, a gradient‐type algorithm based on the state‐space approach in optimal control is utilized.
Adjoint—control transformations for solving practical optimal control problems
Authors: Dixon L. C. W. , Bartholomew‐Biggs M. C. 
Published: July 2010

AbstractThis paper is concerned with some reformulations of the classical computational scheme for solving optimal control problems via Pontryagin's maximum principle. The purpose is to alleviate some well known difficulties involved in solving a two‐point boundary value problem in terms of adjoint variables. To this end there is discussion of the avoidance of explicit use of transversality conditions and the use of initial control rather than adjoint variables as the basis of the iterative procedure. The application of these ideas to some practical problems of spacecraft trajectory optimization is considered.
Optimal repair policy for a machine service problem
Authors: Feichtinger Gustav 
Published: July 2010

AbstractThe paper considers a two‐state stochastic process with a non‐linear cost structure evaluating sojourn in states and transition between them. One transition rate serves as the control variable, and one state probability is selected as the state variable. A non‐linear autonomous optimal control problem is then defined and solved by saddle‐point analysis. Next, a variant of the machine interference problem is analysed (M machines, M repairmen, time‐dependent service intensity). Under reasonable assumptions, the repair intensity is shown to be decreasing for finite planning periods. Analogous results on the qualitative structure of optimal policies can be derived for some other related models, e.g. for an autonomous version of the Kamien‐Schwartz maintenance model and for a simple model of optimal dunning of credit repayment.
Optimal control of linear distributed parameter systems by finite‐element Galerkin's technique
Authors: Rao K. C. , Prabhu S. S. , Mehta S. C. 
Published: July 2010

AbstractThe paper considers a finite‐element discretization for solving two distributed parameter system optimal control problems. Linear and quadratic finite‐element approximations are used in conjunction with Galerkin's method. The first problem involves heating a massive body in a furnace and takes into account furnace dyanmics. The input (fuel flow rate) is magnitude constrained, and the performance index is the terminal cost. The second problem pertains to a plug‐flow heat exchanger and is solved for end‐point control and control along the entire heat exchanger. Uniform wall flux and wall temperature serve as the control variables. The results are compared with earlier results, and advantages of the present approach are discussed.
Singular perturbation method applied to the open‐loop discrete optimal control problem
Authors: Rao A. Kailasa , Naidu D. S. 
Published: July 2010

AbstractThe open‐loop optimal control of a linear, shift‐invariant, singularly perturbed discrete system is considered. The resulting two‐point boundary value problem (TPBVP) is cast in the singularly perturbed form. It is found that in the process of degeneration, the original system loses some of the initial and final conditions. A singular perturbation method is developed to obtain approximate solutions composed of outer series, initial correction series and final correction series to recover the lost boundary conditions. The method is given for zeroth, first and any order of approximation. An example is provided to illustrate the proposed method.
Time suboptimal feedback control of systems described by linear parabolic partial differential equations
Authors: Wong Kin Tuck , Luus Rein 
Published: July 2010

AbstractFeedback control for systems described by linear parabolic partial differential equations is considered from a time suboptimal point of view. A scalar quadratic function representing the deviation from a desired distribution is first formulated, and the rate of approach to the target is maximized by minimizing this quadratic function at each time step. An orthogonal collocation technique enables an accurate low‐order lumped parameter model to be constructed. A direct search optimization can then be used to obtain the optimal quadratic function and, subsequently, the optimal feedback gain matrix for control. The resulting control applied to a diffusion process takes the system to the target rapidly and in a stable manner.
Mismatch and the optimal control of linear systems with time delays
Authors: Hocken R. D. , Marshall J. E. 
Published: July 2010

AbstractTwo control schemes are devised to minimize a quadratic cost functional associated with a time varying linear system, when the linear system forms part of a plant that may contain delays in both control and measurement. Control scheme (1) makes use of prior knowledge of the initial state of the linear system, whereas control scheme (2) does not. Both control schemes contain models of the plant and any difference between plant and model is referred to as mismatch. Matched control scheme (1) is optimal, whereas matched control scheme (2) is optimal if and only if the plant does not contain measurement delay. As matched control scheme (2) is suboptimal for plant with delay in measurement, in this instance mismatch may improve performance. The type of mismatch which may produce this improvement is obtained using a concept referred to as equivalence.
Optimal belaying strategies for rock climbing
Authors: Sorger Gerhard 
Published: July 2010

AbstractIn this paper we analyse a model which describes one section of an Alpine climbing tour. As a control variable, we introduce the intensity of belaying. The objective of control is the maximization of the safety or pleasure of climbing. We focus our attention on the qualitative structure of the optimal belaying strategy and on the question of how it depends on the degree of climbing difficulty. The model is based on a stochastic approach; its solution, however, is derived by means of deterministic control theory.
Program CC's implementation of pole‐placement and lqg algorithms using diophantine equations
Authors: Thompson Peter M. 
Published: July 2010

AbstractPolynomial Diophantine equations can be used to solve pole‐placement problems and linear quadratic Gaussian (LQG) optimal control problems, for both analogue and digital single‐input‐single‐output (SISO) systems. A description is presented of the how these algorithms are implemented in Program CC, a user‐friendly, command driven, computer‐aided‐control‐system‐design (CACSD) package.
Optimal regulator control for systems with time‐varying measurable and partially measurable disturbances
Authors: Ramirez W. Fred , Beyer Kathleen P. , Abedi Hedayat 
Published: July 2010

AbstractThis paper presents extensions to the optimal linear regulator control problem that allow for time‐varying measurable disturbances and partially measurable disturbances. The utility of these new algorithms is domonstrated by stirred‐tank reactor and staged binary distillation column examples.
Decision and forecast horizons in a stochastic environment: A survey
Authors: Bhaskaran Sita , Sethi Suresh P. 
Published: July 2010

AbstractThis paper constructs a unified framework to survey most of the work done to date on decisiondecision horizon replaces the term planning horizon used in the literature in the context of this paper. This is done because of an alternate and more popular use of the term planning horizon as simply the given length of the horizon in a finite horizon problem.
and forecast horizons in a stochastic environment. The paper is divided into sections by type of model. For each model type, the issues of existence of these horizons and of derivation of sufficient conditions for their determination are studied. Appropriate examples are presented.
The Repair VS. Replacement problem: A stochastic control approach
Authors: L'Ecuyer Pierre , Haurie Alain 
Published: July 2010

AbstractThis paper is concerned with a repair vs. replacement problem for a system observed in continuous time and subject to random failure. When the system fails, a decision is taken, based on the observed values of the (random) repair cost and the system's age, to either perform a minimal repair or to replace the system by a new one. At any time, the system may also be replaced preventively, and the aim of the decision maker is to minimize the total expected discounted cost. A dynamic programming approach is proposed to solve this problem. Sufficient conditions under which a repair‐limit rule is optimal are given. An efficient algorithm is devised for the computation of such an optimal policy, and a numerical illustration is worked out.
Periodic Optimal Hypersonic Scramjet Cruise
Authors: Chuang Chien‐Hsiung , Speyer Jason L. 
Published: July 2010

AbstractFuel‐optimal periodic cruise paths are determined numerically for a hypersonic vehicle with more realistic aerodynamic and scramjet engine models than used in previous work. A modification of the shooting method, called the minimizing‐boundary‐condition method, is used to increase the region of convergence of the solution to the two‐point boundary‐value problem required to satisfy the first‐order necessary conditions. The resulting extremal trajectories are shown to be locally minimizing by a second‐order sufficiency condition. Little fuel improvement is obtained over the full‐throttle steady‐state cruise if the model with an engine‐off‐drag penalty is used. However, altitude changes of over 25 per cent from its lowest value on the periodic path are obtained. If the model without engine‐off‐drag penalty is used, the fuel improvement for the optimal periodic cruise is 5 per cent over the full‐throttle steady‐state cruise.
Optimal control of production and marketing systems with distributed time lags
Authors: Choi Sung‐Bin , Hwang Hark 
Published: July 2010

AbstractThis paper deals with the problem of production and advertising policy for a decaying item whose gradual loss of potential or utility is associated with the passage of time, such as grain, photographic film or electronic components. The delay effects of the advertisement on the sales rate are also considered in the problem. This leads to a control problem where the state equations are represented by integro‐differential equations. The objective is to use optimal control theory to determine the production and advertising rates of the decay item which maximize the current value of net profit stream. For the model developed we present a computational procedure of finding the optimal policy and then carry out sensitivity analysis through an example problem. The properties of the optimal solution are discussed for the case of constant rate of delay effect.
An Optimal output feedback control method and application to a motor‐generator system
Authors: Wang Jiaquing , Egami Tadashi , Tsuchiya Takeshi 
Published: July 2010

AbstractA multi‐input/multi‐output feedback control system synthesis method with output feedback structure is proposed on the basis of an improved optimal regulator theory. The method is applied to a DC motor/AC generator system. The effectiveness of the method is demonstrated by simulation and experimental studies. An input‐output relation is derived through the observable canonical form of the state equations of the controlled object, and an improved optimal regulator theory is applied to the relation. The controller consists of proportional actions, integral actions, difference actions and compensating actions for input delay times. The (l — 1) th‐order difference actions are included in the controller for the controlled object in which an lth‐order output subsystem is included. On the other hand, the (n — 1) th‐order difference actions are included in the previous method for the same controlled object. In order to consider the transient response of the designed control system, the relations between the weighting factors in the defined performance index and the transient response are studied by simulation and experiment. Satisfactory responses for a two‐input/two‐output system are obtained in our experiments.