bluuebunny/crossref_metadata_2025 huggingface dataset:
Lentivirus as a tool for lineage‐specific gene manipulations
Authors: Malashicheva Anna , Kanzler Benoît , Tolkunova Elena , Trono Didier , Tomilin Alexey
Published: July 2007

The trophectoderm (TE) of blastocysts, the first epithelium established in mammalian development, (1) plays signaling, supportive, and patterning functions during preimplantation development, (2) ensures embryo implantation into the uterine wall, and (3) gives rise to extraembryonic tissues essential for embryo patterning and growth after implantation. We show that mouse TE, itself permissive to lentiviral (LV) infection, represents a robust nonpermeable physical barrier to the virus particles, thereby shielding the cells of the inner cell mass from viral infection. This LV feature will allow modulations of gene expression in a lineage‐specific manner, thus having significant applications in mouse functional genetics. genesis 45:456–459, 2007. © 2007 Wiley‐Liss, Inc.
Factors associated with suicidal behaviors in a large French sample of inpatients with eating disorders
Authors: Fedorowicz Valérie J. , Falissard Bruno , Foulon Christine , Dardennes Roland , Divac Snezana M. , Guelfi Julien D. , Rouillon Frédéric
Published: July 2007

Objective:

The objective of the present study was to identify factors associated with suicidal behaviors among patients with eating disorders.

Method:

A large database including sociodemographic and clinical characteristics of 1,009 consecutive patients hospitalized for an eating disorder in Paris, France, was examined. Data gathered upon admission to hospital were analyzed to identify factors associated with a history of suicide attempt or current suicidal ideation, among the whole sample as well as among each subtype of eating disorder.

Results:

Among the whole sample, the factor most strongly associated with suicide attempt or suicidal ideation was the diagnostic category, with the highest odds ratio for bulimia nervosa followed by anorexia nervosa of the binging/purging subtype. Among diagnostic subgroups, the strongest factors were drug use, alcohol use, and tobacco use.

Conclusion:

Suicide risk should be monitored carefully among patients with eating disorders, paying particular attention to combinations of risk factors. © 2007 by Wiley Periodicals, Inc. Int J Eat Disord 2007
Cue exposure in the treatment of resistant adolescent bulimia nervosa
Authors: Martinez‐Mallén Esteban , Castro‐Fornieles Josefina , Lázaro Luisa , Moreno Elena , Morer Astrid , Font Elena , Julien Joana , Vila Montserrat , Toro Josep
Published: July 2007

Objective:

A percentage of bulimic patients do not greatly improve with the usual treatment. Therefore, the objective was to further evaluate cue exposure (CE), in order to attain better results in clinical settings.

Method:

Twenty‐two adolescent patients who fulfilled DSM‐IV diagnostic criteria for bulimia nervosa (mean age 16.7, SD 1.5) and who were resistant to the usual treatment followed a program of 12 CE sessions. Clinical characteristics were evaluated and different psychopathological scales were administered at the beginning and the end of the CE program and at 6 month follow‐up. Subjective anxiety and physiological parameters were recorded during the sessions.

Results:

A significant decrease was observed in subjective anxiety (p = .023), heart rate (p < .001), and blood pressure (p = .001) during the first session. A decrease in these parameters was also recorded between the first and the last session. The number of binges per week (p = .005) and the mean score for the psychopathological scales decreased significantly from the beginning of the treatment, and were significantly lower at the end of the CE program and at follow‐up. Purging behaviors per week only decreased significantly after the end of the CE session during the follow‐up (p = .04).

Conclusion:

Anxiety, bingeing, purging, and psychopathological scales improve with a CE program in resistant bulimia nervosa. © 2007 by Wiley Periodicals, Inc. Int J Eat Disord 2007
Chromosome instability and translocation t(11;18) in primary gastric marginal zone B‐cell lymphoma of MALT‐type
Authors: Tibiletti Maria Grazia , Milani Katia , Martin Vittoria , Zucca Emanuele , Motta Teresio , Cortelazzo Sergio , Pinotti Graziella , Mazzucchelli Luca , Pruneri Giancarlo , Martinelli Giovanni , Barbazza Renzo , Capella Carlo , Bertoni Francesco
Published: July 2007

The prognosis for patients with mucosa‐associated lymphoid tissue (MALT) lymphomas is good; these tumours have usually an indolent course with overall survival rates that are greater than 80% at 5‐year, but some rare cases with histological transformation in aggressive diffuse large cell lymphoma have also been diagnosed. Here, we present cytogenetic results on endoscopic bioptic material of 42 cases of primary gastric extranodal marginal zone B‐cell lymphoma (EMZL) using fluorescence in situ hybridization (FISH) approach with API2, MALT1 and centromeric probes for chromosome 3 and 18, and their impact on the clinical outcome. Copyright © 2007 John Wiley & Sons, Ltd.
Surface flux and atmospheric boundary layer observations from the LAPS project over the middle stream of the Huaihe River basin in China
Authors: Tanaka Hiroki , Hiyama Tetsuya , Yamamoto Koh , Fujinami Hatsuki , Shinoda Taro , Higuchi Atsushi , Endo Satoshi , Ikeda Shoichiro , Li Weijing , Nakamura Kenji
Published: July 2007

Observations of the surface layer and the atmospheric boundary layer (ABL) were collected as part of the Lower Atmosphere and Precipitation Study (LAPS), which investigated the relationship between the surface conditions and the ABL processes. The LAPS was part of the Core Research for Evolutional Science and Technology (CREST) program, under the auspices of the Japan Science and Technology Agency (JST). Observations began in August 2003 over a flat surface region in mid‐latitude China at 32·55°N, 116·78°E. Observations before, during, and after the Meiyu season in China provided data for surface conditions varying from relatively dry to moist. Preliminary analysis of the surface and the ABL observations shows relationships between the surface fluxes and the ABL structure. ABL depth was enhanced by sensible heat flux. Fluctuations in the ABL depth corresponded to plume‐like wind structures within the ABL. Day‐to‐day variability in ABL depth was controlled mainly by buoyancy flux over the surface during dry periods. It was also affected by vertical motion at the top of the ABL, especially during wet periods. Copyright © 2007 John Wiley & Sons, Ltd.
Strain field measurements on mouse carotid arteries using microscopic three‐dimensional digital image correlation
Authors: Sutton M.A. , Ke X. , Lessner S.M. , Goldbach M. , Yost M. , Zhao F. , Schreier H.W.
Published: July 2007

A stereomicroscope system is adapted to make accurate, quantitative displacement, and strain field measurements with microscale spatial resolution and nanoscale displacement resolution on mouse carotid arteries. To perform accurate and reliable calibration for these systems, a two‐step calibration process is proposed and demonstrated using a modification to recently published procedures. Experimental results demonstrate that the microscope system with three‐dimensional digital image correlation (3D‐DIC) successfully measures the full 3D displacement and surface strain fields at the microscale during pressure cycling of 0.40‐mm‐diameter mouse arteries, confirming that the technique can be used to quantify changes in local biomechanical response which may result from variations in extracellular matrix composition, with the goal of quantifying properties of the vessel. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Release rate controls biological activity of nerve growth factor released from fibrin matrices containing affinity‐based delivery systems
Authors: Wood Matthew D. , Sakiyama‐Elbert Shelly E.
Published: July 2007

Previously, combinatorial techniques were used to identify peptide sequences exhibiting high, medium, and low affinity for heparin. Bidomain peptides were synthesized containing a transglutaminase sequence for one domain and one of the heparin‐affinity sequences for the other domain. A delivery system was made consisting of bi‐domain peptides, heparin, and nerve growth factor (NGF), which binds to heparin with moderate affinity. The goal of this research was to determine whether peptide affinity for heparin and the molar ratio of peptide to heparin affected the release rate of NGF from the delivery system and the biological activity of NGF released. This study also explored whether peptide affinity modulated biological activity independent of release rate. Mathematically modeling the delivery system confirmed that release could be controlled by both peptide affinity and molar ratio of peptide to heparin. Experimentally, the rate of NGF release from the delivery system was found to be affected by peptide affinity and molar ratio. The delivery system presented biologically active NGF as assayed by embryonic chick dorsal root ganglia (DRGs) neurite extension, where extension was similar to or increased for DRGs grown in fibrin matrices containing the delivery system compared to DRGs grown with NGF in the culture media. Furthermore, by modulating the molar ratio of peptide to heparin in the delivery system, similar release rates of NGF were obtained for different affinity peptides and these conditions promoted similar levels of neurite extension, demonstrating that release rate appears to be the main mechanism controlling the biological activity of released NGF. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Bone tissue engineering using human adipose‐derived stem cells and honeycomb collagen scaffold
Authors: Kakudo Natsuko , Shimotsuma Ayuko , Miyake Shogo , Kushida Satoshi , Kusumoto Kenji
Published: July 2007

Human adipose‐derived stem cells (ASCs) have the capacity to regenerate and the potential to differentiate into multiple lineages of mesenchymal cells. The aim of this study was to investigate the possibility of using honeycomb collagen scaffold to culture ASCs in bone tissue engineering. The osteogenic capacity of ASCs in vitro, was confirmed by histology and measuring the expression of cbfa‐1. After that, ASCs were cultured for up to 14 days in the honeycomb scaffold to allow a high density, three‐dimensional culture. Scanning electron microscopy data showed that the scaffold was filled with the grown ASCs, and calcification, stained black with von Kossa, was confirmed. Furthermore, The ASC‐loaded honeycomb collagen scaffolds cultured for 14 days were subcutaneously transplanted into nude mice, and excised after 8 weeks. Bone formation in vivo was examined using HE stain, von Kossa stain, and osteocalcin immunostain. Those histological views showed significant positive stains in the samples of osteogenic medium in the three types of stain. These results suggest that this carrier is a suitable scaffold for ASCs and will be useful as a three‐dimensional bone tissue engineering scaffold in vitro and in vivo. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Metacarpophalangeal collateral ligament reconstruction using small intestinal submucosa in an equine model
Authors: Bertone Alicia L. , Goin Scott , Kamei Sachiko J. , Mattoon John S. , Litsky Alan S. , Weisbrode Steven E. , Clarke Rhonda B. , Plouhar Pamela L. , Kaeding Christopher C.
Published: July 2007

Xenogeneic porcine small intestinal submucosa (SIS) is a natural, biodegradable matrix that has been successfully used as a scaffold for repair of tissue defects. The goal of this study was to compare a collateral ligament transection surgically reconstructed with an anchored SIS ligament to a sham‐operated control procedure for the correction of joint laxity using an equine model. Ten metacarpophalangeal joints from 10 horses had complete transection of the lateral collateral ligament. In 6 horses, the collateral ligament was reconstructed with a multilaminate strip of SIS anchored with screws into bone tunnels proximal and distal to the joint. The sham controls had similar screws, but no SIS placed. Clinical compatibility and effectiveness were evaluated with lameness, incisional quality, and joint range of motion, circumference and laxity. Ligament structure and strength was quantified with serial high resolution ultrasound, histology, and mechanical testing at 8 weeks. Surgical repair with SIS eliminated joint laxity at surgery. SIS‐treated joints had significantly less laxity than sham treatment at 8 weeks (p< 0.001). SIS‐treated ligaments demonstrated a progressive increase in repair tissue density and fiber alignment that by week 8 were significantly greater than sham‐treated ligament (p< 0.03). SIS‐repaired ligament tended to have greater peak stress to failure than sham‐treatment (p< 0.07). Cellularity within the ligament repair tissue and inflammation within the bone tunnel was significantly greater in the SIS‐treated limbs (p< 0.017). Within the first 8 weeks of healing, SIS implanted to reinforce collateral ligament injury was biocompatible in the joint environment, restored initial loss of joint stability, and accelerated early repair tissue quality. SIS ligament reconstruction might provide benefit to early ligament healing and assist early joint stability associated with ligament injury. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Homogeneous chitosan‐PLGA composite fibrous scaffolds for tissue regeneration
Authors: Shim In Kyung , Lee Sang Young , Park Yoon Jeong , Lee Myung Chul , Lee Sang Hoon , Lee Jue Yeon , Lee Seung Jin
Published: July 2007

Novel chitosan‐poly(lactide‐co‐glycolide) (PLGA) composite fibers and nonwoven fibrous scaffolding matrices were designed for cartilage regeneration. A homogenous one‐phase mixture of chitosan and PLGA at a ratio of 50:50 (w/w %) was successfully produced using cosolvents of 1,1,1,3,3,3‐hexafluoroisopropanol and methylene chloride. A wet spinning technique was employed to fabricate composite fibrous matrices. Physical characterizations of one‐phase chitosan‐PLGA composite (C/Pc) matrices were performed for their homogeneity, in vitro degradability, mechanical property and wettability in comparison to two‐phase chitosan and PLGA composite fibrous matrices in which PLGA was dispersed in a continuous chitosan phase. The one‐phase property of C/Pc matrices was confirmed from thermal analysis. Significantly retarded degradation was observed from the composite C/Pc fibrous matrices in contrast to the PLGA‐dispersed chitosan (C/Pd) fibrous matrices due to the effective acid‐neutralizing effect of chitosan on acid metabolites of PLGA. The composition of chitosan with PLGA resulted in a characteristic soft and strong mechanical property that could not be retained by either PLGA or the chitosan fibers. In addition, the presence of chitosan in the composite matrices provided proper wettability for cell cultivation. The C/Pc matrices were further investigated for their scaffolding function using chondrocytes for cartilage regeneration. Enhanced cell attachment was observed on the composite matrix compared with the PLGA fibrous matrices. The mRNA expression of type II collagen and aggrecan was upregulated in the composite matrix owing to the superior cell compatibility of chitosan. These results suggest an excellent potential for C/Pc one‐phase composite fibrous matrices as scaffolding materials for tissue regeneration. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Controlled release of an antibiotic, gentamicin sulphate, from gravity spun polycaprolactone fibers
Authors: Chang H.‐I. , Lau Y.‐C. , Yan C. , Coombes A.G.A.
Published: July 2007

The antibiotic, gentamicin sulphate (GS), was incorporated in gravity‐spun polycaprolactone (PCL) fibers by spinning from particulate suspensions of the drug in PCL solution to produce a controlled delivery system. The production rate of GS‐loaded PCL fibers was confined to the range 1–1.5 m/min and the fiber diameter to 170–220 μm. The kinetics of drug release could be adjusted by varying the GS loading of the fibers and the suspension preparation conditions. Gradual release of ∼80% of the initial GS content was measured in phosphate buffered saline at 37°C over 50 days from fibers spun from nonhomogenized suspensions, whereas loss of this amount of antibiotic occurred in less than 10 days from fibers spun from homogenized suspensions. Studies of growth inhibition of Stapyhlococcus epidermidis in culture indicated that GS released after 2 weeks from PCL fibers retained antibacterial activity. This behavior recommends further investigation of PCL fibers for local delivery of antibiotics to combat infection associated with periodontal disease, musculoskeletal injuries, and implantation of fiber‐based tissue substitutes such as vascular prostheses. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Bond length and the electron density at the bond critical point: XX, ZZ, and CZ bonds (X = Li‐F, Z = Na‐Cl)
Authors: Castillo Norberto , Robertson Katherine N. , Choi S. C. , Boyd Russell J. , Knop Osvald
Published: July 2007

The aim was to investigate the relationship between the bond length and the electron density at the bond critical point in homonuclear XX and ZZ and heteronuclear CZ bonds (X = Li‐F, Z = Na‐Cl). Thed,ρcpairs were obtained from 472 target bonds in DFT‐optimized (B3LYP/6‐311+G(d,p)) small molecular species. These species were selected arbitrarily but with a view to maximize the range widthsWRfor each atom combination. It was found that (i) with one clear exception, thed(A−A) means (A = X or Z) correlate linearly with the bond lengthsd(A2) of the respective diatomic molecules; (ii) thed(A−A) means correlate parabolically withn, the formal number of valence electrons in the atoms of the bond; and (iii) with increasing sample size N the ratioWR(ρc)/WR(d) appears to converge toward a representationf[WR(ρc)/WR(d)]N→∞characteristic of A. Detailed analysis of thed,ρcrelationship has shown that by and large simple power regression accounts best for the DFT data. The regression coefficients ofd=aρand ρc= αd−β(b,β> 0) vary withnin a seemingly irregular manner but one that is consistent with simple chemical notions. Thed(A2) can be approximated in terms of multilinear MO electron occupancies. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2008
Zebrafish dentition in comparative context
Authors: Stock David W.
Published: July 2007

Studies of the zebrafish (Danio rerio) promise to contribute much to an understanding of the developmental genetic mechanisms underlying diversification of the vertebrate dentition. Tooth development, structure, and replacement in the zebrafish largely reflect the primitive condition of jawed vertebrates, providing a basis for comparison with features of the more extensively studied mammalian dentition. A distinctive derived feature of the zebrafish dentition is restriction of teeth to a single pair of pharyngeal bones. Such reduction of the dentition, characteristic of the order Cypriniformes, has never been reversed, despite subsequent and extensive diversification of the group in numbers of species and variety of feeding modes. Studies of the developmental genetic mechanism of dentition reduction in the zebrafish suggest a potential explanation for irreversibility in that tooth loss seems to be associated with loss of developmental activators rather than gain of repressors. The zebrafish and other members of the family Cyprinidae exhibit species‐specific numbers and arrangements of pharyngeal teeth, and extensive variation in tooth shape also occurs within the family. Mutant screens and experimental alteration of gene expression in the zebrafish are likely to yield variant tooth number and shape phenotypes that can be compared with those occurring naturally within the Cyprinidae. Such studies may reveal the relative contribution to trends in dental evolution of biases in the generation of variation and sorting of this variation by selection or drift.J. Exp. Zool. (Mol. Dev. Evol.) 308B:523–549, 2007. © 2007 Wiley‐Liss, Inc.
Oxidation of 14C‐labeled compounds perfused by microdialysis in the brains of free‐moving rats
Authors: Zielke H. Ronald , Zielke Carol L. , Baab Peter J.
Published: July 2007

The oxidative capacity of the brain for alternate substrates, glucose, lactate, pyruvate, acetate, glutamate, and glutamine was determined by using microdialysis to infuse 14C‐labeled compounds into the interstitial fluid of adult rat brain and by collecting the brain‐generated 14CO2 from the dialysis eluate. All compounds were readily oxidized. The recovery of 14CO2 was enhanced for those compounds metabolically close to entry into the TCA cycle or known to have a low interstitial concentration. Two compounds, pyruvate and lactate, demonstrated reciprocal competition when added as nonradioactive competitors. Oxidation of two amino acids, 14C‐glutamate and 14C‐glutamine, was stimulated by the addition of nonradioactive acetate and pyruvate. α‐Cyano‐4‐hydroxycinnamate decreased 14C‐lactate and 14C‐pyruvate oxidation, consistent with the transport of both compounds via a monocarboxylate transporter. The results of this in vivo study support the results of previous in vitro studies that showed that a wide range of compounds formed from glucose in the brain are also oxidized in the brain for energy production. © 2007 Wiley‐Liss, Inc.
Sensitivity enhancement in saturation transfer difference (STD) experiments through optimized excitation schemes
Authors: Cutting Brian , Shelke Sachin V. , Dragic Zorica , Wagner Beatrice , Gathje Heiko , Kelm Soerge , Ernst Beat
Published: July 2007

Investigation of ligand–protein interactions by the saturation transfer difference (STD) experiment has been well established in the drug discovery process through numerous examples. Thus, binding epitopes may be mapped by comparing signals of the ligand with and without saturation of the protein. Herein, it is shown that a less selective process allows more protons to assist in the saturation of the protein, thereby considerably enhancing the sensitivity of the STD experiment. Increasing the saturation power entails a greater risk of perturbing the ligand; however, an amplitude modulation of the waveform assists this procedure by distributing the applied energy in sidebands. Copyright © 2007 John Wiley & Sons, Ltd.
Voter's role in a democracy
Authors: Dodds Harold W.
Published: July 2007

The fate of our way and individual freedom ia wrapped up in the vigor and eflectiveness of voluntary civic groups.
Big government not inevitable
Authors: Lilienthal David E.
Published: July 2007

TVA administration cited by Lilienthal as example of national policy carried out by state and local agencies.
An effective chief executive
Authors: Gravlin Leslie M.
Published: July 2007

Minnesotds first “manager” tells how state department of administration relieves governor of time‐consuming detail.
Local press as civic force
Authors: Reichler Oxie
Published: July 2007

Most valuable contribution a newspaper can make to decent government is day‐to‐day getting of the story and telling it.
Politicians serve as teachers
Authors: Roberts Aileen
Published: July 2007

Connecticut civics faculties go back to classrooms where governor, legislators and other state officials preside.
If at first you don't succeed
Authors: Tucker William P.
Published: July 2007

Citizen efforts to secure increased funds for St. Paul Schools and teacher salaries rewarded on fourth attempt.
What ails county justice
Authors: Temple Ralph R.
Published: July 2007

Scrambled judicial and executive duties of independent local oficials have resulted in confusion and inefficiency.
30 years with manager plan
Authors: Donnelley Paul
Published: July 2007

Wichita turns out for [Know Your City] week celebration to mark anniversary of change with civic festivities.
Let cities manage themselves
Authors: Walker Harvey
Published: July 2007

Home rule will continue to be hampered unless legislators, city officials and judges learn to understand its aims.
Drama gets out the vote
Authors: Hamilton Mr. Charles Henry
Published: July 2007

Richmond's [Gold Feather Day] overcomes citizen apathy and brings ten times usual number of voters to the polls.
Old county, new troubles
Authors: Pate James E.
Published: July 2007

Warwick, one of Virginia's original shires, may lose either its people or its eficiency because its population grew.
Income tax aids annexation
Authors: Anderson R. T.
Published: July 2007

New levy helps Toledo reduce property taxed, making city attractive to suburbanites who also pay city payroll levy.
Decentralized minimum‐energy control and coordination of large scale linear systems
Authors: Gruver W. A. , Hedges J. C. , Snyder W. E.
Published: July 2007

A two‐level hierarchical algorithm of the interaction prediction type is derived for the decentralized optimal control of linear systems with fixed terminal state, linear interactions, and a minimum energy criterion. The algorithm is noniterative at the infimal level and utilizes successive approximation with averaging for the coordination. Numerical experiments compare the effect of the interactions, sampling times, and time horizon on the convergence of the algorithm.
Perturbation‐magnitude control for difference‐quotient estimation of derivatives
Authors: Kelley Henry J. , Lefton Leon , Johnson Ivan L.
Published: July 2007

A process for adjusting perturbation magnitude for accurate difference‐quotient estimation of derivatives is described in the following. The process is intended to be carried out sequentially, alternating with iterations of a parameter‐optimization algorithm. A more complex and computationally‐expensive scheme for occasional auxiliary use is also described.
The automation of transversality conditions
Authors: Schappelle Robert H. , Brusch Richard G.
Published: July 2007

This paper presents a flexible, user‐oriented algorithm for the numerical implementation of the terminal point transversality conditions associated with optimal control problems. The method differs from the usual numerical implementation in that the constant Lagrange multipliers associated with terminal constraints are eliminated numerically during program execution rather than being eliminated analytically prior to program coding. This conceptual innovation gives the user considerable flexibility in specifying new sets of terminal boundary conditions without reprogramming.
Self‐scaling variable metric methods in hilbert space with applications to control problems
Authors: Turner P. R. , Huntley E.
Published: July 2007

In this paper the application of the self‐scaling variable metric methods to optimal control problems is considered. The convergence of such methods in Hilbert space, both with and without line searches, is established for a wide class of convex functionals. The methods are then tested numerically on control problems, and the results are compared with earlier results for other variable metric algorithms.
Minimum altitude‐loss soaring in a sinusoidal vertical wind distribution
Authors: Pierson Bion L. , Chen Imao
Published: July 2007

Minimum altitude‐loss flight of a sailplane through a given vertical wind distribution is discussed. The problem is posed as a non‐linear optimalcontrol problem, and several numerical solutions are obtained using a gradient projection algorithm. The initial and final states are required to be equal, though they may be either fixed or free. An unexpected new optimal trajectory type is found to exist for relatively short ranges and free boundary conditions.
The solution of finite‐time optimal control problems with control time delays
Authors: Grimble M. J.
Published: July 2007

The design of deterministic LQP optimal control systems is considered for plants with control delays and a finite optimization interval. First, a solution is obtained to the fixed end‐point optimal control problem. An expression for the open‐loop optimal control is derived in the s‐domain. The closed‐loop optimal time‐varying gain matrix is then calculated from the s‐domain results. The open‐loop and closed‐loop solutions to the free end‐point optimal control problem are also given. The constant gain, infinite‐time, feedback control law is obtained as a limiting case of these results.

The receding‐horizon optimal control problem for plants with control signal delays is also considered. The solution to this problem yields a constant feedback gain matrix which has obvious advantages for implementation. This gain matrix is not the same as the constant solution to the infinite‐time problem. The receding‐horizon control laws are derived for both the fixed and free end‐point problems, and these are shown to produce asymptotically stable closed‐loop systems.
Further properties of bounds on the quadratic cost of linear multivariable optimal regulators
Authors: Johnson M. A.
Published: July 2007

Some new results continuing the development of a theory for bounding the optimal value of a quadratic cost function subject to a linear system constraint are presented.

The observed property of the nesting of increasing orders of bounds is formalized and proven. This property is shown to be related to the successive inclusion of the constraint sets. A unified result for the nesting and convergence of the bound sequences is also given to conclude this analysis.

Extension of the bound derivation to that of a limiting situation based on the introduction of an asymptotic parameter into the control weight is developed in detail. The upper bounds are shown to collapse into a single value, and the lower bounds form a set of nested limit values.
Optimal shape of an elastic structure
Authors: Sakawa Yoshiyuki , Ukai Hiroyuki
Published: July 2007

This paper treats an optimal design problem of an elastic upright structure which can be regarded as a column. The optimal shape of the structure, which makes the lowest natural frequency as large as possible, is determined under several equality and inequality constraints. A necessary condition for optimality is derived, and a numerical procedure for obtaining the optimal shape is discussed. The piecewise Hermite interpolation technique and the Rayleigh‐Ritz method are employed for computing the smallest eigenvalue and the corresponding eigenfunction. Several numerical results are presented.
The effects of non‐linear kinematics in optimal evasion
Authors: Forte I. , Steinberg A. , Shinar J.
Published: July 2007

The effects of non‐linear kinematics on optimal evasive strategies from a pursuer guided by proportional navigation are investigated in a plane. Non‐linear analysis is mandatory since, for certain values of system parameters and initial conditions, linearized kinematic models are not valid. The investigation discloses two principles of optimal evasion. For long pursuit time, both principles are satisfied and the relatively large miss distance is almost independent of the initial conditions. Short pursuit time does not allow simultaneous satisfaction of both principles, and the two‐dimensional optimal compromise results in a reduced miss distance. The inability to satisfy both principles suggests a three‐dimensional manoeuvre perpendicular to the initial collision plane.
Optimal forest fire control with limited reinforcements
Authors: Parlar Mahmut
Published: July 2007

A forest fire fighting model is generalized to include the possibility of dispatching reinforcements whose size may be limited for the particular fire. The resulting deterministic optimal control problem with free final time and a moving boundary equality constraint on the final state and with bounded state and control variables is solved by the maximum principle. The optimal control is found to be a bang‐bang control which can switch at most twice until the final time.
An explicit feedback approximation for medium‐range interceptions in a vertical plane
Authors: Shinar J. , Negrin M.
Published: July 2007

Minimum‐time interception of a target flying at a constant speed and altitude by a missle‐carrying fighter aeroplane is analysed using the method of forced singular perturbations (FSP). The engagement starts beyond visual range and terminates when the firing envelope of the missile is reached. Since in a medium‐range scenario the interceptor does not reach its maximum specific energy, the solution consists of matched initial and terminal boundary layers. The paper concentrates on interception of high flying targets for which the terminal phase is also a climbing subarc. The solution of this problem is approximated in a uniformly valid explicit feedback form using a range‐dependent weighting parameter. Application to an interceptor with realistic aerodynamic and propulsion models serves as an illustrative example.
A navigation algorithm using measurement‐based extrapolation
Authors: Stubberud Allen R.
Published: July 2007

An element in the guidance loop of any aircraft is the navigation system. This system derives position (and sometimes velocity) information by combining data from various on‐board and external measurement devices and transmits it to the guidance algorithm.

In this paper a navigation algorithm is designed for an aircraft which has on‐board inertial measurements, range measurements from a TACAN station, and range, elevation and azimuth measurements from a ground‐based radar. The basic design philosophy is the predictor‐corrector form for a recursive estimator. State prediction is accomplished by extrapolation of the inertial measurements rather than from Newton's second law. This eliminates major modelling problems caused by the aircraft's aerodynamics. State correction is accomplished using optimal linear stochastic estimation methods. The resulting estimator (navigation algorithm) is essentially an ‘extended Kalman filter’ which processes the above‐mentioned inputs and generates optimal (in a linearized sense) estimates of the aircraft's latitude, longitude and altitude.
A dual formulation of the algebraic riccati equation problem
Authors: Incertis Fernando
Published: July 2007

By introducing a set of matrix transformations, the algebraic Riccati equation (ARE) is converted into a ‘dual’ matrix quadratic equation (DARE) where the unknown belongs to the field of skew‐symmetric matrices. As a consequence of this reformulation for a matrix space Rnxn the system of n(n+ 1)/2 coupled quadratic equations associated to ARE is shown to be equivalent to another system of n(n‐1)/2 coupled quadratic equations. An efficient computational algorithm is given for solving the dual Riccati equation and closed form analytical solutions of ARE are derived for the case in which n=2 or when some special, but non‐trivial, commutativity conditions are fulfilled in the transformed space.
A new approach to identification of linear systems and the optimal solution of a class of synthesis problems
Authors: Emre Erol
Published: July 2007

A unifying solution is given to the problems of optimal deadbeat control, disturbance decoupling, exact model matching and system identification. It is shown that the optimal solutions of these problems can be obtained by solving a new type optimization problem. Our solution makes use of certain recent results on system structure and on geometric and polynomial theories of linear systems.
Comparison of two optimal feedback controls for parabolic systems
Authors: Amouroux M. , Courdesses M. , Jai A. El.
Published: July 2007

Two numerical methods for solving minimum energy control problem with final state constraints are presented for parabolic systems. In infinite dimensions, the functional analysis approach gives an explicit solution from which an approximation method is developed to allow the removal of the indetermination which causes numerical difficulties. The Riccati equation approach about the penalized criterion is also studied and the two solutions are compared on the implemented control laws (in finite dimensions). An example is presented.
Optimal employment strategies of profit‐maximizing and labour‐managed firms
Authors: Feichtinger Gustav
Published: July 2007

This paper deals with the problem of finding optimal hiring and firing policies for profit‐maximizing and labour‐managed firms whose objective is to maximize profits and net income per worker, respectively. Assuming a concave production function with labour force as a variable production factor, a non‐linear demand function, increasing marginal production costs, and convex costs of changing the labour force, we determine the optimal employment strategies by the maximum principle. By using phase portrait analysis, we prove that for a relatively small manpower stock the optimal policies of the profit‐maximizing firms are to increase its labour force over time such that the increase is largest in the beginning. However, for a ‘large’ initial stock, firing can be optimal at the beginning. For a labour‐managed firm, the same behaviour is shown to be optimal for the infinite‐time‐horizon problem only under additional assumptions. The joint analysis of profit‐maximizing and labour‐managed firms provides a possibility to compare the optimal stationary employment policies.
On the hierarchical algorithms for nonlinear systems with bounded control
Authors: Mahmoud Magdi S. , Fawsy Ahmed S.
Published: July 2007

Hierarchical algorithms for the dynamic optimization of non‐linear systems with control bound inequality, constraints are considered. Three different computational schemes are developed, based on the costate prediction co‐ordination. Each scheme consists of four levels; of which the second level manipulates the control constraints in an explicit way. Digital simulation of the developed algorithms on a typical power control system is presented.
Optimal pricing of a monopoly against a competitive producer
Authors: Dockner Engelbert
Published: July 2007

In 1977, Lieber and Barnea presented an investment and pricing differential game. There are two players, a monopoly possessing some exhaustible resource and a price‐taking competitor. The monopoly wishes to determine an optimal price, whereas the competitor wishes to choose optimal investment in an alternative production. This paper presents a non‐linear extension of the game. The special structure of the game permits a complete solution in the state—costate phase plane as well as in the control phase plane. The monopoly plays an optimal decreasing price strategy and the competitor plays an optimal decreasing investment strategy with an increasing production capacity.
Incentive‐compatible allocation algorithm for non‐separable group payoffs
Authors: Ho Y. C. , Yang Z. J. , Servi L.
Published: July 2007

This paper introduces an incentive‐compatible resource allocation scheme for non‐separable group payoffs. It is shown that the algorithm can be made convergent and truth inducing under reasonable assumptions. A real‐world motivating example is included.
Optimal impulsive manoeuvres and aerodynamic braking
Authors: Jezewski D. J.
Published: July 2007

An impulsive optimization method and the results of a suboptimal atmospheric guidance program are combined to produce an efficient solution to the aero‐braking problem. For a specified initial and final orbit, the solution determines: (1) the minimum of the sum of the magnitudes of the impulse vectors, (2) the optimal atmospheric entry and exit state vectors (subject to both equality and inequality constraints) and (3) the optimal coast times. Numerical solutions are presented to illustrate characteristics of the solution.
Optimal boundary impedance for the minimization of reflection: (I) Asymptotic solutions by the geometrical optics method
Authors: Chen Goong , Bridges Thomas J.
Published: July 2007

In the design of surfaces which absorb waves, the impedance boundary condition is used as an effective means of diminishing the reflection. In this paper, we use the geometrical optics method to approximate the optimal impedance value which minimizes the reflected field for the scalar wave equation with a monochromatic source. Our treatment yields good results for optimal impedance in the asymptoticity region of the geometrical optics solution.
The adjustment and integration of accelerometer data using steady‐state feedback gains
Authors: Murray Daniel M.
Published: July 2007

The adjustment of noisy accelerometer data to prevent drift in the velocity and displacement trajectories is formulated as a discrete‐time optimal control problem. It is shown that large penalties on the terminal velocity and displacement produce large feedback gains towards the end of the time interval and result in unrealistic adjustments. An adjustment procedure is proposed in which a small penalty is placed on the entire time history of the velocity and displacement. The solution of the associated algebraic Riccati equation yields steady‐state feedback gains which produce satisfactory adjustments of the acceleration measurements and generate realistic velocity and displacement trajectories.
Block‐independent control of distributed structures
Authors: Silverberg L. M. , Meirovitch L.
Published: July 2007

As a compromise between coupled control and independent modal‐space control, a block‐independent control method is proposed. The computational difficulties encountered in coupled control are thereby reduced significantly. The requirement on the number of actuators is shown to be lower for block‐independent control than for independent modal‐space control, but only moderately so. A numerical example is presented.
Optimal control analysis of a simple criminal prosecution model
Authors: Gerchak Yigal , Parlar Mahmut
Published: July 2007

This paper analyzes an optimal control model dealing with a problem in criminal justice policy. It is assumed that a society generates criminals at a constant rate. The size of the criminal population at any time depends on the criminal generation rate and the number of criminals prosecuted and imprisoned. Optimal prosecution rate over time is found by using Pontryagin's principle. The objective is to minimize the total discounted cost of the damages inflicted by the criminals plus the cost of law enforcement. Explicit forms of the optimal trajectories are found in both the finite and infinite horizon cases. In the latter case, a stability analysis of the optimal steady‐state is also presented. The paper concludes with a comparative statics analysis of the equilibrium and a description of the optimal control of a more detailed criminal justice system model.
A unified approach to reduced‐order modelling and control of large‐scale systems with multiple decision makers
Authors: Saksena Vikram R. , Cruz J. B.
Published: July 2007

This paper presents a unified approach to reduced‐order modelling and control of large‐scale systems with multiple decision makers. The ‘core’ of a large game problem is identified through the information structure and the class of structure preserving strategies. The induced decomposition results in a low‐order game problem and two decentralized optimal control problems. An example of a two‐area power system demonstrates the computational attractiveness of the proposed design methodology.
Numerical simulation of a non‐linear feedback controller for a wind tunnel model involving a time delay
Authors: Manitius A. , Tran H.
Published: July 2007

This paper describes a non‐linear, S‐minimum time, feedback controller for a wind tunnel model and a numerical simulation of its performance. The model is a linear third‐order system with delay and a state‐variable constraint; it represents the dynamics of a Mach number control loop in a cryogenic wind tunnel. The design method involves a singular perturbation technique, an impulse control and a compensation of delay. Peformance of linear and non‐linear S‐minimum time control is compared in various operating conditions. The closed‐loop dynamics of the non‐linear system is examined by numerical simulations which exhibit the boundary‐layer phenomena in the control and the effects of various changes in parameters.
On the solution of the decoupling problem in lqg optimal systems
Authors: Chen Bor‐Sen , Kung Chung‐Chun
Published: July 2007

In this paper, we study the input‐output decoupling of the LQG optimal system. Two frequency dependent weighting matrices, Q(s) and R(s), in the cost functional J are specified to achieve the desired decoupled design. Furthermore, the pole‐zero placement in the LQG decoupled system is also discussed. The Wiener‐Hopf approach (frequency domain technique) will be applied to solve the above problems.
On remuneration patterns for medical services
Authors: Hartl Richard , Mehlmann Alexander
Published: July 2007

An optimal control problem describing the changes in a patient population is presented. Different remuneration patterns for medical services are considered, and their influences on the physicians' curing efforts are investigated. It is shown that an ideal health care system should not reward the number of patients but the effects of the physicians' curing efforts.
Energy state revisited
Authors: Kelley Henry J. , Cliff Eugene M. , Weston Alan R.
Published: July 2007

Minimum‐time climbs in the ‘energy’ approximation are reviewed and further consideration given to choice of variables. A pair of variables which seems to offer an attractive replacement for altitude and air‐speed in singular‐perturbation procedures is suggested. Use of the new variables in an energy‐modelled climb‐dash problem is illustrated.
The effect of sample period on optimally designed servomechanism control systems
Authors: Diduch C. P. , Doraiswami R.
Published: July 2007

A uniform approach for comparing sampled‐data servomechanism control systems with respect to the sample period is formulated such that a quadratic performance measure of the augmented continuous system states and discrete controller states is used both for controller design and performance evaluation. The structure of the controller and performance cost is optimally designed as a function of the sample period and converges to an optimal continuous control system as the sample period approaches zero. Extensive simulation reveals that the performance cost increases and that the norm of the controller gains decreases monotonically with the sample period.
Two pursuers and one evader in the plane: A stochastic pursuit‐evasion differential game
Authors: Yavin Y.
Published: July 2007

A stochastic pursuit‐evasion differential game involving three players moving in the plane is considered. The players are E, the evader, and Pi (where i = 1,2), the pursuers. It is assumed that all players have complete observation of each other's positions. Also, each of the pursuers has a killing range and a detection range. If player E is intercepted by at least one of the pursuers before leaving the detection range of either of them, then the pursuers win the game. If, on the other hand, E leaves the detection range of one (or both) of the pursuers before being intercepted, then player E wins the game. Sufficient conditions on max‐min pursuit‐evasion strategies are derived. These conditions require the existence of a properly smooth solution to a non‐linear partial differential equation on a torus in R3. By applying a finite‐difference method, the equation is solved numerically, and the max‐min pursuit‐evasion strategies are computed.
Optimum rate allocation in quantized control
Authors: Meadow Charles J. , Fischer Thomas R. , Gibson Jerry D.
Published: July 2007

A linear‐quadratic‐Gaussian (LQG) delocalized control problem is formulated to require both specification of a control law and communication of measurements to controller and controls to plant. Efficient communication requires quantization of both measurement and control signals. The basic design problem is to allocate in an optimum fashion a fixed total communication rate to the measurement and control communication systems.

A dynamic communication‐rate allocation algorithm is developed on the basis of prediction error and entropy power. As intuitively expected, the rate allocation depends on both the measurement and plant noise powers as well as the overall quadratic performance measure. Solely on the basis of entropy power considerations, a larger rate should be allocated for communication of measurements than for communication of controls.