bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sampled‐data iterative learning control with well‐defined relative degree
Authors: Sun Mingxuan , Wang Danwei , Wang Youyi 
Published: April 2004

AbstractThis paper addresses the problem of iterative learning control with well‐defined relative degree. The solution is a family of sampled‐data learning algorithms using lower‐order differentiations of the tracking error with the order less than the relative degree. A unified convergence condition for the family of learning algorithms is derived and is proved to be independent of the highest order of the differentiations. In the presence of initial condition errors, the system output is ensured to converge to the desired trajectory with a specified error bound at each sampling instant. The bound will reduce to zero whenever the bound on initial condition errors tends to zero. Numerical examples are provided to illustrate the tracking performance of the proposed learning algorithms. Copyright © 2004 John Wiley & Sons, Ltd.
Robust control from data in presence of input saturation
Authors: Canale M. 
Published: April 2004

AbstractIn this paper, conditions are given for internal model control (IMC) structures to be robustlyL2stable with respect toH∞bounded model uncertainty and in presence of input saturation. This conditions are used for the design robust controllers that are the bestH∞approximation to ‘perfect’ linear control among all controllers guaranteeingL2stability in presence of actuator saturation. The cases of both ‘standard’ and enhanced IMC structures are considered. Copyright © 2004 John Wiley & Sons, Ltd.
Involvement of endogenous CCK and CCK1 receptors in colonic motor function
Authors: Varga Gábor , Bálint András , Burghardt Beáta , D'Amato Massimo 
Published: April 2004

Cholecystokinin (CCK) is a brain‐gut peptide; it functions both as a neuropeptide and as a gut hormone. Although the pancreas and the gallbladder were long thought to be the principal peripheral targets of CCK, CCK receptors are found throughout the gut. It is likely that CCK has a physiological role not only in the stimulation of pancreatic and biliary secretions but also in the regulation of gastrointestinal motility. The motor effects of CCK include postprandial inhibition of gastric emptying and inhibition of colonic transit. It is now evident that at least two different receptors, CCK1 and CCK2 (formerly CCK‐A and CCK‐B, respectively), mediate the actions of CCK. Both localization and functional studies suggest that the motor effects of CCK are mediated by CCK1 receptors in humans. Since CCK is involved in sensory and motor responses to distension in the intestinal tract, it may contribute to the symptoms of constipation, bloating and abdominal pain that are often characteristic of functional gastrointestinal disorders in general and irritable bowel syndrome (IBS), in particular. CCK1 receptor antagonists are therefore currently under development for the treatment of constipation‐predominant IBS. Clinical studies suggest that CCK1 receptor antagonists are effective facilitators of gastric emptying and inhibitors of gallbladder contraction and can accelerate colonic transit time in healthy volunteers and patients with IBS. These drugs are therefore potentially of great value in the treatment of motility disorders such as constipation and constipation‐predominant IBS.British Journal of Pharmacology (2004) 141, 1275–1284. doi:10.1038/sj.bjp.0705769
MathSBML: a package for manipulating SBML-based biological models
Authors: Shapiro Bruce E. , Hucka Michael , Finney Andrew , Doyle John 
Published: April 2004

Abstract
Summary: MathSBML is a Mathematica package designed for manipulating Systems Biology Markup Language (SBML) models. It converts SBML models into Mathematica data structures and provides a platform for manipulating and evaluating these models. Once a model is read by MathSBML, it is fully compatible with standard Mathematica functions such as NDSolve (a differential-algebraic equations solver). MathSBML also provides an application programming interface for viewing, manipulating, running numerical simulations; exporting SBML models; and converting SBML models in to other formats, such as XPP, HTML and FORTRAN. By accessing the full breadth of Mathematica functionality, MathSBML is fully extensible to SBML models of any size or complexity.
Availability: Open Source (LGPL) at http://www.sbml.org and http://www.sf.net/projects/sbml.
Supplementary information: Extensive online documentation is available at http://www.sbml.org/mathsbml.html. Additional examples are provided at http://www.sbml.org/software/mathsbml/bioinformatics-application-note
Effects of Subanesthetic Ketamine on Regional Cerebral Glucose Metabolism in Humans
Authors: Långsjö Jaakko W. , Salmi Elina , Kaisti Kaike K. , Aalto Sargo , Hinkka Susanna , Aantaa Riku , Oikonen Vesa , Viljanen Tapio , Kurki Timo , Silvanto Martti , Scheinin Harry 
Published: April 2004

Background
The authors have recently shown with positron emission tomography that subanesthetic doses of racemic ketamine increase cerebral blood flow but do not affect oxygen consumption significantly. In this study, the authors wanted to assess the effects of racemic ketamine on regional glucose metabolic rate (rGMR) in similar conditions to establish whether ketamine truly induces disturbed coupling between cerebral blood flow and metabolism.

Methods
18F-labeled fluorodeoxyglucose was used as a positron emission tomography tracer to quantify rGMR on 12 brain regions of interest of nine healthy male volunteers at baseline and during a 300-ng/ml ketamine target concentration level. In addition, voxel-based analysis was performed for the relative changes in rGMR using statistical parametric mapping.

Results
The mean +/- SD measured ketamine serum concentration was 326.4+/-86.3 ng/ml. The mean arterial pressure was slightly increased (maximally by 16.4%) during ketamine infusion (P < 0.001). Ketamine increased absolute rGMR significantly in most regions of interest studied. The greatest increases were detected in the thalamus (14.6+/-15.9%; P = 0.029) and in the frontal (13.6+/-13.1%; P = 0.011) and parietal cortices (13.1+/-11.2%; P = 0.007). Absolute rGMR was not decreased anywhere in the brain. The voxel-based analysis revealed relative rGMR increases in the frontal, temporal, and parietal cortices.

Conclusions
Global increases in rGMR seem to parallel ketamine-induced increases in cerebral blood flow detected in the authors' earlier study. Therefore, ketamine-induced disturbance of coupling between cerebral blood flow and metabolism is highly unlikely. The previously observed decrease in oxygen extraction fraction may be due to nonoxidative glucose metabolism during ketamine-induced increase in glutamate release.
Moderate Increase in Intraabdominal Pressure Attenuates Gastric Mucosal Oxygen Saturation in Patients Undergoing Laparoscopy
Authors: Schwarte Lothar A. , Scheeren Thomas W. L. , Lorenz Christel , De Bruyne Filip , Fournell Artur 
Published: April 2004

Background
Perioperative disturbances of microvascular blood flow and oxygenation in the intestinal tract have been hypothesized to play an important role in development of the multiple organ dysfunction syndrome. Herein, increased intra-abdominal pressure (IAP) has been identified as a key factor in the initiation of the pathophysiologic cascade. The authors hypothesized that increasing the IAP by intraperitoneal insufflation of carbon dioxide attenuates microvascular oxygen saturation in gastric mucosa. They tested this hypothesis in a prospective, observational study in 16 patients scheduled to undergo elective diagnostic laparoscopy.

Methods
The authors continuously assessed microvascular oxygen saturation in gastric mucosa by reflectance spectrophotometry. Simultaneously systemic oxygen saturation, heart rate, arterial blood pressure, and ventilation-derived variables were measured noninvasively. During general anesthesia and controlled mechanical ventilation, baseline values were obtained. Thereafter, the IAP was increased to 8 and 12 mmHg, respectively, followed by a control period after desufflation.

Results
The increase in IAP from baseline to 8 mmHg decreased microvascular oxygen saturation in gastric mucosa from 69+/-7% (mean +/- SD) to 63+/-8% at 8 mmHg IAP (P <0.05), with a further significant reduction to 54+/-13% at 12 mmHg IAP (P <0.01). Microvascular oxygen saturation in gastric mucosa recovered rapidly to baseline level (66 +/- 10%) after release of increased IAP. In striking contrast to regional mucosal oxygen saturation, systemic oxygenation did not change with either of the interventions.

Conclusions
The results suggest that increasing intraabdominal pressure to moderate levels, commonly applied to induce a surgical pneumoperitoneum, decreases gastric mucosal oxygen saturation.
Cerebral Oxygen Extraction and Autoregulation during Extracorporeal Whole Body Hyperthermia in Humans
Authors: Cremer Olaf L. , Diephuis Jan C. , van Soest Hanneke , Vaessen Paul H. B. , Bruens Marcel G. J. , Hennis Pim J. , Kalkman Cor J. 
Published: April 2004

Background
The effects of hyperthermia on the human brain are incompletely understood. This study assessed the effects of whole body hyperthermia on cerebral oxygen extraction and autoregulation in humans.

Methods
Nineteen patients with chronic hepatitis C virus infection, not responding to interferon treatment, were subjected to experimental therapy with extracorporeal whole body hyperthermia at 41.8 degrees C for 120 min under propofol anesthesia (23 sessions total). During treatment series A (13 sessions), end-tidal carbon dioxide was allowed to increase during heating. During series B (10 sessions), end-tidal carbon dioxide was maintained approximately constant. Cerebral oxygen extraction (arterial to jugular venous difference of oxygen content) and middle cerebral artery blood flow velocity were continuously measured. Cerebral pressure-flow autoregulation was assessed by static tests using phenylephrine infusion and by assessing the transient hyperemic response to carotid compression and release.

Results
For treatment series A, cerebral oxygen extraction decreased 2.2-fold and cerebral blood flow velocity increased 2.0-fold during heating. For series B, oxygen extraction decreased 1.6-fold and flow velocity increased 1.5-fold. Jugular venous oxygen saturation and lactate measurements did not indicate cerebral ischemia at any temperature. Static autoregulation test results indicated loss of cerebrovascular reactivity during hyperthermia for both series A and series B. The transient hyperemic response ratio did not decrease until the temperature reached approximately 40 degrees C. Per degree Celsius temperature increase, the transient hyperemic response ratio decreased 0.07 (95% confidence interval, 0.05-0.09; P = 0.000). This association remained after adjustment for variations in arterial partial pressure of carbon dioxide, mean arterial pressure, and propofol blood concentration.

Conclusion
Profound hyperthermia during propofol anesthesia is associated with decreased cerebral oxygen extraction, increased cerebral blood flow velocity, and impaired pressure-flow autoregulation, indicating transient partial vasoparalysis.
Endothelial Glycocalyx as an Additional Barrier Determining Extravasation of 6% Hydroxyethyl Starch or 5% Albumin Solutions in the Coronary Vascular Bed
Authors: Rehm Markus , Zahler Stefan , Lötsch Michael , Welsch Ulrich , Conzen Peter , Jacob Matthias , Becker Bernhard Friedrich 
Published: April 2004

Background
The impact on the endothelial glycocalyx for the extravasation of colloidal infusion solutions has not been investigated sufficiently.

Methods
Isolated guinea pig hearts were perfused with Krebs-Henseleit buffer in a Langendorff mode. Solutions of 0.9% saline, 5% albumin (70 kd), or 6% hydroxyethyl starch (200 kd) were infused into the coronary system for 20 min at a rate of one third of the coronary flow, also during reperfusion after 15 min of ischemia, and after enzymatic digestion of the endothelial glycocalyx by heparinase. Net coronary fluid filtration was assessed directly by measuring the formation of transudate on the epicardial surface, and solute extravasation was assessed by measuring albumin and hydroxyethyl starch in the coronary effluent and transudate. Hearts were perfusion fixed to visualize the endothelial glycocalyx using transmission electron microscopy.

Results
Only infusion of hydroxyethyl starch, not infusion of albumin, significantly decreased net coronary fluid filtration. Heparinase application without ischemia increased coronary leak by 25% but did not accelerate the passage of colloids. Ischemia alone did not alter permeability. However, there was a large (approximately +200%), transient (approximately 4 min) increase in permeability for water, albumin, and hydroxyethyl starch after ischemia with heparinase application. Also, histamine (10 m) only increased permeability after pretreatment of the hearts with heparinase. The thickness of the glycocalyx after colloid administration was 0.2-0.3 microm. No glycocalyx could be detected after application of heparinase.

Conclusion
The endothelial glycocalyx acts as a competent barrier for water and colloids. Only after its destruction do changes in endothelial morphology (postischemic reperfusion or histamine application) become effective determinants of coronary extravasation.
Solution structure of Phrixotoxin 1, a specific peptide inhibitor of Kv4 potassium channels from the venom of the theraphosid spider Phrixotrichus auratus
Authors: Chagot Benjamin , Escoubas Pierre , Villegas Elba , Bernard Cédric , Ferrat Gilles , Corzo Gerardo , Lazdunski Michel , Darbon Hervé 
Published: April 2004

AbstractAnimal toxins block voltage‐dependent potassium channels (Kv) either by occluding the conduction pore (pore blockers) or by modifying the channel gating properties (gating modifiers). Gating modifiers of Kv channels bind to four equivalent extracellular sites near the S3 and S4 segments, close to the voltage sensor. Phrixotoxins are gating modifiers that bind preferentially to the closed state of the channel and fold into the Inhibitory Cystine Knot structural motif. We have solved the solution structure of Phrixotoxin 1, a gating modifier of Kv4 potassium channels. Analysis of the molecular surface and the electrostatic anisotropy of Phrixotoxin 1 and of other toxins acting on voltage‐dependent potassium channels allowed us to propose a toxin interacting surface that encompasses both the surface from which the dipole moment emerges and a neighboring hydrophobic surface rich in aromatic residues.
An efficient system for high‐level expression and easy purification of authentic recombinant proteins
Authors: Catanzariti Ann‐Maree , Soboleva Tatiana A. , Jans David A. , Board Philip G. , Baker Rohan T. 
Published: April 2004

AbstractExpression of recombinant proteins as fusions to the eukaryotic protein ubiquitin has been found to significantly increase the yield of unstable or poorly expressed proteins. The benefit of this technique is further enhanced by the availability of naturally occurring deubiquitylating enzymes, which remove ubiquitin from the fusion product. However, the versatility of the system has been constrained due to the lack of a robust, easily purified deubiquitylating enzyme. Here we report the development of an efficient expression system, utilizing the ubiquitin fusion technique, which allows convenient high yield and easy purification of authentic protein. An Escherichia coli vector (pHUE) was constructed for the expression of proteins as histidine‐tagged ubiquitin fusions, and a histidine‐tagged deubiquitylating enzyme to cleave these fusions was expressed and purified. The expression system was tested using several proteins varying in size and complexity. These results indicate that this procedure will be suitable for the expression and rapid purification of a broad range of proteins and peptides, and should be amenable to high‐throughput applications.
Scaling Up Learning Models in Public Good Games
Authors: Arifovic Jasmina , Ledyard John 
Published: April 2004

AbstractWe study three learning rules (reinforcement learning (RL), experience weighted attraction learning (EWA), and individual evolutionary learning (IEL)) and how they perform in three different Groves–Ledyard mechanisms. We are interested in how well these learning rules duplicate human behavior in repeated games with a continuum of strategies. We find that RL does not do well, IEL does significantly better, as does EWA, but only if given a small discretized strategy space. We identify four main features a learning rule should have in order to stack up against humans in a minimal competency test: (1) the use of hypotheticals to create history, (2) the ability to focus only on what is important, (3) the ability to forget history when it is no longer important, and (4) the ability to try new things.
Adolescent Sexual Decision‐Making; An Integrative Review
Authors: Hulton Linda J. 
Published: April 2004

AbstractPurpose(1) The purpose of this integrative review was to summarize the present literature to identify factors associated with adolescent sexual decision‐making. Thirty‐eight salient research studies were selected as a basis of this review from the databases of Medline, CINAHL, and Psychinfo using the Cooper methodology (Cooper, 1982 [13]).Conclusions(2) Two categories of decision‐making were identified: 1) The research on factors related to the decisions that adolescents make to become sexually active or to abstain from sexual activity; 2) The research on factors related to contraceptive decision‐making. The most consistent findings were that the factors of gender differences, cognitive development, perception of benefits, parental influences, social influences, and sexual knowledge were important variables in the decision‐making processes of adolescents.Implications(3) Practice implications for nursing suggest that clinicians should assess adolescent sexual decision‐making in greater detail and address the social and psychological context in which sexual experiences occur. Nurses must be aware of the differences between adolescent and adult decision‐making processes and incorporate knowledge of growth and development into intervention strategies. Moreover, to the degree that adolescent sexual decision‐making proves to be less than rational, interventions designed to improve competent sexual decision‐making are needed.
A Synthesis of What We Know About the Use of Physical Restraints and Seclusion with Patients in Psychiatric and Acute Care Settings: 2003 Update
Authors: Bower Fay L. , McCullough Cynthia S. , Timmons Mae E. 
Published: April 2004

AbstractPurpose(1) This article is an update of the January 19, 2000, Volume 7, Number 2 article of the synthesis of research findings on the use of restraint and seclusion with patients in psychiatric and acute care settings.Conclusions(2) The little that is known about restraint/seclusion use with these populations is inconsistent. Attitudes and perceptions of patients, family, and staff differ. However, all patients had very negative feelings about both, whether they were restrained/secluded or observed by others who were not restrained. The reasons for restraint/seclusion use vary with no accurate use rate for either. What precipitates the use of restraint/seclusion also varies, but professionals claim they are necessary to prevent/treat violent or unruly behavior. Some believe seclusion/restraint is effective, but there is no empirical evidence to support this belief. Many less restrictive alternatives have been tested with varying outcomes. Several educational programs to help staff learn about different ways to handle violent/confused patients have been successful.Implications(3) Until more is known about restraint/seclusion use from prospective controlled research, the goal to use least restrictive methods must be pursued. More staff educational programs must be offered and the evaluation of alternatives to restraint/seclusion pursued. When seclusion/restraint is necessary, it should be used less arbitrarily, less frequently, and with less trauma. As the Joint Commission on Accreditation of Healthcare Organizations (JCAHO) and the Health Care Financing Administration (HCFA) have prescribed, “Seclusion and restraint must be a last resort, emergency response to a crisis situation that presents imminent risk of harm to the patient, staff, or others” (p. 25) [99A].
Effects of scaling and root planing on the amounts of interleukin‐1 and interleukin‐1 receptor antagonist and the mRNA expression of interleukin‐1β in gingival crevicular fluid and gingival tissues
Authors: Yoshinari Nobuo , Kawase Hitoshi , Mitani Akio , Ito Masamitsu , Sugiishi Shin , Matsuoka Masanori , Shirozu Norimitsu , Ishihara Yuichi , Bito Boku , Hiraga Makoto , Arakawa Kyoko , Noguchi Toshihide 
Published: April 2004

Objective:  The purpose of this study was to evaluate the relationship between the clinical changes after non‐surgical periodontal therapy and interleukin 1 (IL‐1) in gingival crevicular fluid (GCF) and gingival tissues from patients with chronic periodontitis.Background:  The inflammatory responses mediated by IL‐1 play an important role in periodontal tissue destruction. Although numerous studies have attempted to elucidate the dynamic movement involved in chronic periodontitis, the results have often conflicted. Such discrepancies may have been due to the inability to determine clinical disease activity.Methods:  Seven patients with chronic periodontitis were examined. The severity of periodontal inflammation was expressed using clinical parameters before and after a scaling and root planing (SRP) procedure. The amounts and concentrations of IL‐1α, IL‐1β and IL‐1 receptor antagonist in GCF were measured by enzyme‐linked immunosorbent assay (ELISA) and IL‐1 activity index was calculated. A needle biopsy in matching gingival tissues was also performed before and after the SRP procedure. The localization and mRNA expression of IL‐1β were determined using histological methods.Results:  Clinical parameters improved slightly after the SRP procedure. Only the probing pocket depth (PPD) was reduced significantly (p < 0.05). However, the amount of IL‐1β in GCF was slightly increased. The localization and mRNA expression of IL‐1β could still be observed after the SRP procedure. Therefore, none of the clinical parameters showed a high sensitivity or specificity for evaluating subgingival inflammation.Conclusion:  These observations suggest that IL‐1 is effective for evaluating in detail the state of subgingival inflammation.