bluuebunny/crossref_metadata_2025 huggingface dataset:
Treatment and outcomes for epistaxis in children with Glanzmann's thrombasthenia
Authors: Rosas R. Raul , Kurth Margaret Heisel , Sidman James
Published: July 2010

Objectives/Hypothesis:

To understand Glanzmann's thrombasthenia and provide insight to the management of epistaxis in children with this disease.

Study Design:

Retrospective chart review.

Methods:

All children diagnosed with Glanzmann's thrombasthenia and treated for epistaxis at Children's Hospitals and Clinics of Minnesota were identified and a retrospective chart review was performed. Outpatient charts, hospitalization records, and operative reports were reviewed from 1999 up to 2009 and appropriate data were extracted. The episodes of epistaxis, therapy used, complications, and success rates for controlling hemorrhage were noted.

Results:

Five children with a total of 63 clinical encounters for epistaxis were identified. Forty‐seven encounters required hospitalization, close to half of which necessitated medical care in the intensive care unit. Nearly all encounters required infusion of hemostatic therapy with either single or multiple agents. Seventy‐one procedures for life‐threatening hemorrhage were performed. The most common (n = 24) intervention was administration of bovine collagen matrix, which was successful only half of the time (50%). Anterior and posterior nasal packing with or without hemostatic material completely resolved hemorrhage in 35% of the procedures.

Conclusions:

To date, no form of medical or surgical intervention in children with this condition has consistently demonstrated its ability resolve nasal hemorrhage. The role of the otolaryngologist is to control bleeding during major episodes of nasal hemorrhage that do not respond to medical management. These patients usually have remarkable improvement in the frequency and severity of epistaxis in adolescence and then require much less aggressive therapy. Laryngoscope, 120:2374–2377, 2010
Role of tumor necrosis factor–α in wound repair in human vocal fold fibroblasts
Authors: Chen Xia , Thibeault Susan L.
Published: July 2010

Objectives/Hypothesis:

Tumor necrosis factor–α (TNF‐α) is an inflammatory cytokine and apoptotic molecule that appears to be a mediator in inflammation and fibrosis. The objective of this investigation was to examine the effects of TNF‐α on 3D Carbylan‐GSX in vitro cultured human vocal fold fibroblasts (hVFFs), to provide insight into the mechanism responsible for the improved vocal fold wound healing that has been previous reported with Carbylan‐GSX treatment.

Study Design:

In vitro cell culture.

Methods:

hVFF were cultured in 3D Carbylan‐GSX and on polystyrene with different dosages of TNF‐α (0, 0.1, 1, 10, and 100 ng/mL) with and without 10% fetal bovine serum (FBS). hVFF response to TNF‐α was characterized by morphology, proliferation rates, and gene transcript levels for matrix metalloproteinase 1 (MMP1), matrix metalloproteinase 2 (MMP2), tissue inhibitor of metalloproteinase 3 (TIMP3), collagen I, collagen III, fibronectin, and TNF‐α receptor.

Results:

In 3D Carbylan‐GSX, TNF‐α inhibited hVFF proliferation in a dose‐dependent manner. TNF‐α (0.1–100 ng/mL) was shown to significantly downregulate TIMP3 and extracellular matrix–related mRNA transcript levels for collagen III and fibronectin and to upregulate MMP1 and MMP2 expression, resulting in increased MMP/TIMP3 ratios. TNF‐α receptor expression was significantly upregulated in Carbylan‐GSX compared to control polystyrene. Responses were more marked in 10% FBS culture.

Conclusions:

After vocal fold injury, locally injected Carbylan‐GSX can enhance the role of TNF‐α in remodeling the lamina propria layer of the vocal fold, accelerating wound healing. Carbylan‐GSX has potential as a new therapeutic approach that may lead to better treatment of vocal fold wound healing. Laryngoscope, 2010
Comparison of gentamicin distribution in the inner ear following administration via the endolymphatic sac or round window
Authors: Zhang Yiliang , Zhang Ru , Dai Chunfu , Steyger Peter S. , Yu Yongfu
Published: July 2010

Objective/Hypothesis:

The distribution of gentamicin in the inner ear via the endolymphatic sac (ES) or round window (RW) routes was investigated.

Study Design:

Experimental study.

Methods:

A fluorescent gentamicin‐Texas Red conjugate (GTTR) was adopted to visualize the gentamicin. Adult guinea pigs were treated with GTTR applied to the ES or RW, the animals were allowed to recover for 3 days, then confocal microscopy was used to observe and quantify GTTR distributions in cochlear and vestibular sensory epithelium.

Results:

When GTTR was applied via the ES, strong GTTR labeling was observed in the vestibule while little GTTR was detected in the cochlea (P < .0001). However, distinct GTTR fluorescence was observed in the cochlea and vestibule following RW application (P = .7967). There was less GTTR labeling in cochlea via ES application than through RW administration (P < .0001).

Conclusions:

ES drug application may be preferable for the treatment of intractable Meniere's disease. Laryngoscope, 2010
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

Objective:

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

Objectives/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
Participative management
Authors: Cattabiani E. J. , White Randall P.
Published: July 2010

This article is taken from a talk presented to the Human Resources Manage‐ment Conference of the United States Office of Personnel Management by Mr. Cattabiani with the assistance of Dr. White.
Consequences
Authors: McCall Morgan W. , Kaplan Robert E.
Published: July 2010

After a decision come the consequences. As the authors show, these are sometimes unexpected, not everyone will interpret them in the same light, and not everyone will value them in the same way. Yet, like it or not, managers must live with and stand by their decisions. What's a manager to do? Read on.
Five challenging assignments
Authors: Lombardo Michael M.
Published: July 2010

Based on a Center study of executive learning, growth and change, this article looks at five assignment types that appear to be especially important in the development of successful managers. To be part of a forth‐coming book co‐authored by Morgan McCall and Ann Morrison of the Center.
George's problem
Authors: Ruderman Marian N.
Published: July 2010

Many organizations have hundreds of young managers with enough talent and drive to make it to the top. Who are they? Will they just naturally win out over the also‐rans? Can anyone predict who will succeed? Is there anything you can do?
Stress and the eye of the beholder
Authors: McCauley Cynthia D.
Published: July 2010

A challenging, rewarding task for one person may be flooded with stress and anxiety for others. How one appraises self and situation makes all the difference. Aware of the link between stress and health and performance problems, managers are taking a closer look at that appraisal process.
Risk, adventure, and the management of self
Authors: Ghiselin Bernie
Published: July 2010

Warren Bennis, one of America's leading organizational theorists, talks about his own triumphs and failings, describing leadership in terms of adventure and exploration.
Cinderella doesn't live here anymore
Authors: Bunker Kerry A.
Published: July 2010

An increasing number of women in middle management find theselves so totally work focused they have no satisfying non‐work lives. To these talented people, the promise of a balanced life seems impossible. What can be done?.
Managing new product development strategically
Authors: Wall Stephen J. , White Randall P.
Published: July 2010

A business may find itself in one of four strategic states. Successful new product development begins with a realistic assessment of that strategic state.
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

The 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.

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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

Aloe‐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.
Selachians and actinopterygians from the Upper Jurassic of Tendaguru, Tanzania
Authors: Arratia G. , Kriwet J. , Heinrich W.-D.
Published: July 2010

Abstract. The first Late Jurassic selachian and actinopterygian fishes of Tendaguru in Tanzania were collected by the German-Tendaguru expedition in 1909–1913. They are represented mainly by occasional teeth of a neoselachian (Sphenodus) and several specimens of a neopterygian (Lepidotes). New material collected by the German-Tanzanian Tendaguru expedition in 2000 includes additional selachians recovered from clay stones at site Dwa 5a and isolated actinopterygian remains. At least three hybodonts (Hybodus sp., Hybodontidae indet., Lonchidion sp.) and a new neoselachian batoid are presented here. This assemblage is endemic to Tendaguru. A new batoid genus and species, Engaibatis schultzei, is described, which is the oldest record of a ray from Gondwana. The actinopterygians are represented by scarce and disarticulated scales of Lepidotes, "pholidophoriform"-like scales, and teleostean vertebrae. This material includes new biogeographic records for Africa. In addition, a synopsis of Jurassic fishes from Africa is presented. Die Fischfauna aus dem Oberjura von Tendaguru ist bisher nur unzureichend bekannt. Das erste Material, das von der Deutschen Tendaguru-Expedition (1909–1913) gesammelt wurde, besteht fast nur aus einigen wenigen isolierten Zähne des Haies Sphenodus und mehreren Exemplaren des Actinopterygiers Lepidotes. Neue Funde, die während der Deutsch-Tansanischen-Tendaguru-Expedition im Jahre 2000 geborgen wurden, erlauben es, mehrere Taxa zu beschreiben, die aus dem Oberjura Afrikas noch nicht bekannt waren. Anhand von Zähnen konnten mindestens drei zu den ursprünglichen Hybodontiern zählende Taxa (Hybodus sp., Hybodontidae indet., Lonchidion sp.) nachgewiesen sowie ein für Tendaguru neuer Rochen (Engaibatis schultzei n. gen. and n. sp.) festgestellt werden. Actinopterygier sind durch wenige und disartikulierte Schuppen von Lepidotes und einer "pholidophoriden"-ähnlichen Form sowie durch Wirbel von Teleosteern vertreten. Das neue Material gibt wichtige Hinweise auf die paläobiogeographische Verbreitung der spätjurassischen Fische. Es wird ein Überblick über die bisher bekannten jurassischen Fischfaunen Afrikas gegeben. doi:10.1002/mmng.20020050112x
Bei Reach und Co verschwimmen die Grenzen
Authors: Geldsetzer Felix O.
Published: July 2010

Das 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

This 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

An 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

The 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

This 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

The 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

The 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

A 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

This 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

The 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

The 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

The 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

Feedback 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

Two 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

In 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

Polynomial 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

This 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

This paper constructs a unified framework to survey most of the work done to date on decision

decision 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

This 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

Fuel‐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

This 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

A 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.
Optimal shape design and unilateral boundary value problems: Part II
Authors: Haslinger J. , Neittaanmäki P. , Tiihonen T. , Kaarna A.
Published: July 2010

The shape optimization of an elastic body in contact with a rigid surface is considered. An existence result for optimal shapes as well as a numerical realization are stated. From several numerical results it can be seen that minimizing the total potential energy of the system leads to an even distribution of contact forces on the contact boundary, even in the cases when the contact involves friction.
Comparison of direct optimization algorithms for dynamic network flow control
Authors: Papageorgiou M. , Mayr R.
Published: July 2010

Several direct optimization algorithms for dynamic non‐linear optimal control problems with bounded control inputs are reviewed. The algorithms are based on well‐known conjugate gradient and variable metric methods for unconstrained optimization. Scaling is shown to improve the algorithms' performance considerably. Comparison of the algorithms is provided for a real‐life example of sewer network flow control.
Optimal control of solar cooling systems
Authors: Salman M. , Kotob S. , Juraidan M.
Published: July 2010

In this paper a control algorithm that minimizes the auxiliary energy consumption in a typical solar cooling system while maintaining appropriate comfortable conditions in the cooled enclosure is devised. A dynamic mathematical model for a lithium bromide‐water absorption chiller is developed to be used for deriving the optimal control algorithm. Finally, the results of simulation of the optimal control algorithm indicate that a net reduction of more than 30% in auxiliary energy is possible.
Impulse response matching for z‐Domain identification with application to model order reduction
Authors: Miller D. F.
Published: July 2010

This paper presents a deterministic time‐domain approach to z‐domain model identification. Coefficients for a discrete transfer function model of specified order are determined by matching the model's impulse response to that of an observed system. Interestingly, the specialized identification equations that result coincide with those from the conventional least‐squares theory using regression models and thus provide a link between the deterministic and stochastic theories. The technique is applied to the model reduction problem for discrete linear systems.
Optimal time joint‐trajectory planning for an industrial manipulator using linear interpolation
Authors: Jeon Hong Tae , Eslami Mansour
Published: July 2010

The path of an industrial manipulator in a crowded workspace generally consists of a set of Cartesian straight‐line segments connecting a set of two adjacent points. To achieve the Cartesian straight‐line path (segment) is, however, a non‐trivial task, and an alternative approach is to place enough intermediate points along a desired path and linearly interpolate between these points in the joint space. A method is developed that determines the subtravelling and transition times such that the total travelling time for this path is minimized subject to the maximum joint velocity and acceleration constraints. These results are simulated on a digital computer using a six‐joint revolute manipulator to show their applications.
The solution of some difficult problems in low‐thrust interplanetary trajectory optimization
Authors: Bartholomew‐Biggs M. C. , Dixon L. C. W. , Hersom S. E. , Maany Z. A.
Published: July 2010

This paper deals with an approach to the problem of spacecraft trajectory optimization that has been successful on a wide range of practical examples. A particular group of missions involving low‐thrust solar‐powered vehicles has presented difficulties for the method, however, and these are described and discussed. In particular the problems seem to reveal weaknesses in some current algorithms for constrained minimization, and we therefore consider some new optimization routines. We also derive a new formulation of the problem using eccentricity and momentum vectors as state variables rather than the more usual Cartesian co‐ordinates. This reformulation allows us to make some simplifying assumptions which make the problem easier to solve while still furnishing good estimates of the true optimum.
The Control of environmental pollution and optimal investment and employment decisions: A Discussion of methodological and modelling issues
Authors: Forster Bruce A.
Published: July 2010

In a recent issue of this Journal, Lin1 analyses a pollution control model that is designed to include adjustment costs, investment, employment and inflation. His analysis of the control theoretic solution appears to contain a number of errors which are pointed out below. Also, the model that he constructs has some awkward features in the view of this analyst. My concerns with the model are outlined in the second section of this comment.
Optimal complex modal‐space control of rotating disc vibrations
Authors: Lee Chong‐Won , Byun Seung‐Wan
Published: July 2010

Optimal modal‐space control of rotating disc vibrations in a complex field is presented. Adoption of the complex notation reduces the order of the system dealt with so as to eliminate the difficulties encountered in formulation and computation. A new technique of choosing a weighting matrix is also suggested for the optimal regulator design. With this technique the backward and forward travelling waves are weighted independently by employing the wave co‐ordinates. The performance of the proposed scheme is finally illustrated through an example.
Introduction of a new process with learning about installation and operation
Authors: Fuller J. David
Published: July 2010

A model is formulated and solved to investigate the optimal introduction of a new production process when the unit cost of the old process increases with cumulative output and the new process is subject to two learning curves. Capital costs of the new process come down with cumulative experience of installation of new capacity, and operating costs are reduced as operating experience accumulates. Demand is assumed to be constant. Because of an upper limit on the rate of expansion of capacity, conversion to the new process takes place gradually over an interval. It is shown that an equivalent, constant capital cost of the new process may be calculated before solving the model; the same may be done for the operating cost in some cases. An example with oil from the Canadian tar sands as the new process is solved, and extensions to the model are discussed.
Radiation effects on styrene–butadiene–ethylene–propylene diene monomer‐multiple walled carbon nanotube nanocomposites: vulcanization and characterization
Authors: Dubey K. A. , Bhardwaj Y. K. , Chaudhari C. V. , Goel N. K. , Sabharwal S. , Rajkumar K. , Chakraborty S. K.
Published: July 2010

Varying compositions of styrene–butadiene rubber (SBR) and ethylene–propylene diene monomer (EPDM) 50:50 blend containing multiple walled carbon nanotube (MWNT) as nanoparticulate filler (0.5–5%) were prepared and their efficacy for radiation vulcanization was analyzed by gel‐content, Charlesby‐Pinner parameter, and crosslinking density measurements. Radiation sensitivity of the nanocomposites increased with increase in the MWNT fraction and radiation dose in the dose range studied. The elastic modulus, tensile strength increased with the radiation dose, while elongation at break exhibited downward trend. The extent of reinforcement as assessed using Kraus equation suggested high reinforcement of blend on MWNT addition. The reinforcing mechanism of nanocomposites was studied by various micromechanics models which predicted higher modulus than the experimentally observed results, indicating agglomeration in the nanocomposites. The thermal stability of the composites increased with increase in MWNT loading has been attributed to the antioxidancy induced by nanotubes and higher crosslinking extent of the nanocomposites. Copyright © 2010 John Wiley & Sons, Ltd.
Electrical conductivity enhancement of polyaniline by refluxing
Authors: Zhang Keqing , Li Yu
Published: July 2010

The room temperature electrical conductivity of polyaniline (PANI) was found to increase remarkably after it was heated in tetrahydrofuran (THF) with refluxing for a certain period and then doped with methanesulfonic acid (MSA). The enhanced electrical conductivity of PANI was attributed to a partially cross‐linked network generated via the formation of new chemical bonds between adjacent PANI chain segments during thermal treating, which may shorten the inter‐chain distance and facilitate inter‐chain transition of charge carriers in doped PANI. During the refluxing, the moderate dissolving power for PANI as well as a much lower boiling point of THF were considered to have a unique effect on the formation of such partially cross‐linked network in PANI. As a comparison, PANI treated in poor solvents like methanol (or ethanol) and PANI treated in dimethyl formamide (DMF), which is a better solvent than THF but has higher boiling point, did not show an obviously increased electrical conductivity. Study on X‐ray diffraction (XRD) analysis of PANI after refluxing showed that crystallinity decreased gradually with the increase of cross‐linking degree, but the inter‐chain cross‐linking probably occurred first in crystalline region and then in the amorphous region. Electrical conductivity of PANI decreased after it was refluxed with THF for an extended period due to the decreased crystallinity and doping in PANI. Copyright © 2010 John Wiley & Sons, Ltd.
Participation in an ambulatory e‐pharmacovigilance system
Authors: Haas Jennifer S. , Iyer Aarthi , Orav E. John , Schiff Gordon D. , Bates David W.
Published: July 2010

Purpose

There is growing concern about whether passive surveillance can detect adverse drug events (ADEs). Our objective was to demonstrate the reach of an interactive voice response system (IVRS) to systematically monitor symptoms experienced by ambulatory patients prescribed one of 31 medications, and to document whether there were differences in our ability to contact certain populations.

Methods

Patients receiving a prescription for a target medication at one of 11 clinics were eligible for a cross‐sectional IVRS survey, “e‐pharmacovigilance,” with a follow‐up survey done 3 months later if the target medication was still listed on the patient's active medication list.

Results

902 patients participated, representing 43.3% of contacted and 25.7% of potentially eligible patients with a working phone. After adjustment for demographics and drug class, patients >66 years were more likely to participate than those 56–65 years (odds ratio 1.47; 95% confidence interval 1.19–1.81). Hispanics were less likely than whites (0.56; 0.42–0.76), and those in low‐income communities less likely to participate than those in high‐income communities (0.69; 0.58–0.82). Patients prescribed asthma, or seizure medications were more likely to participate than those prescribed medications for insomnia. Of patients reached by the system, those prescribed medications were erectile dysfunction and smoking cessation were less likely, and those prescribed seizure medication were more likely to participate.

Conclusions

IVRS technology can be used to perform ambulatory e‐pharmacovigilance for a broad spectrum of patients, particularly older individuals who may at particular risk for ADEs. Copyright © 2010 John Wiley & Sons, Ltd.
Increased risk of hip fracture in the elderly associated with prochlorperazine: is a prescribing cascade contributing?
Authors: Caughey Gillian E. , Roughead Elizabeth E. , Pratt Nicole , Shakib Sepehr , Vitry Agnes I. , Gilbert Andrew L.
Published: July 2010

Purpose

To examine the prescribing of prochlorperazine secondary to the prescribing of a medicine which could lead to symptoms for which prochlorperazine is indicated and commonly used. Given the range of potential hypotensive, sedative, dystonic and other extra‐pyramidal side effects associated with prochlorperazine, its association with hip fracture was also examined.

Methods

Prescription/event sequence symmetry analyses were undertaken from 1st January 2003 to 31st December 2006, using administrative claims data from the Department of Veterans' Affairs, Australia. This method assesses asymmetry in the distribution of an incident event (either prescription of another medicine or hospitalization) before and after the initiation of prochlorperazine. Crude and adjusted sequence ratios (ASR) with 95% confidence intervals (CI) were calculated.

Results

A total of 34 235 persons with incident use of prochlorperazine were identified during the study period. Statistically significant positive associations were found for a number of commonly used medicines, including cardiovascular medicines, NSAIDs, opioids and sedatives and the subsequent initiation of prochlorperazine that ranged from 1.07 (95%CI 1.01–1.14) for diuretics to 1.50 (95%CI 1.40–1.61) for statins. Prescription event analysis showed a 49% (95%CI 1.19–1.86) increased risk of hospitalisation for hip fracture following dispensing of prochlorperazine.

Conclusions

Prescribers should consider the possible contributing role of newly initiated medicines with the potential to cause of dizziness, and where possible address this through dose reduction or cessation of the medicine, rather than prescribing prochlorperazine. Copyright © 2010 John Wiley & Sons, Ltd.
Estimation of the morphology development of immiscible liquid–liquid systems during single screw extrusion
Authors: Domingues N. , Gaspar‐Cunha A. , Covas J.A.
Published: July 2010

A mathematical model to predict the evolution of the morphology of immiscible liquid–liquid systems in single screw extruders has been developed. The model computes the dimensions of the dispersed phase in the polymeric matrix, taking into account the stretching, break‐up, and coalescence phenomena. The corresponding routine was inserted in a process modeling software, describing the flow in a single screw extruder from hopper do die. The drop dimensions were computed along the melting and melt conveying zones. This enabled the study of the morphological evolution of a two‐phase liquid system in a single screw extruder, taking into consideration the effects of the material properties, operating conditions, and screw geometry. The limited experimental data obtained was generally in line with the theoretical predictions. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers