Tracking differentiator based back-stepping control for valve-controlled hydraulic actuator system.

Back-stepping design method is widely used in high-performance tracking control tasks As is known to all, the controller based on back-stepping design will become complex as the model order increases, which is the so called "explosion of terms" problem. In this paper, a tracking differentiator (TD) based back-stepping controller is proposed to handle the "explosion of terms" problem. Instead of calculating the derivatives of intermediate control variables through tedious analytical expressions, for the proposed method, the tracking differentiator is embedded into each recursive procedure to generate the substitute derivative signal for every intermediate control variable. As a result, the complexity of implementation procedure of back-stepping controller is significantly reduced. The discrepancies between the derivative substitutes and the real derivatives are considered. And the effects on control performances caused by the discrepancies are analyzed. In addition to giving the theoretical results and the stability proofs with Lyapunov methods, the developed controller design method is evaluated through a series of experiments with a hydraulic robot arm position serve system. The control performance of the proposed controller is verified by the experiments results.

Duration of intravenous antibiotic therapy in people with cystic fibrosis.

BACKGROUND: Respiratory disease is the major cause of mortality and morbidity in cystic fibrosis (CF). Life expectancy of people with CF has increased dramatically in the last 40 years. One of the major reasons for this increase is the mounting use of antibiotics to treat chest exacerbations caused by bacterial infections. The optimal duration of intravenous antibiotic therapy is not clearly defined. Individuals usually receive intravenous antibiotics for 14 days, but treatment may range from 10 to 21 days. A shorter duration of antibiotic treatment risks inadequate clearance of infection which could lead to further lung damage. Prolonged courses of intravenous antibiotics are expensive and inconvenient and the incidence of allergic reactions to antibiotics also increases with prolonged courses. The use of aminoglycosides requires frequent monitoring to avoid some of their side effects. However, some organisms which infect people with CF are known to be multi-resistant to antibiotics, and may require a longer course of treatment. OBJECTIVES: To assess the optimal duration of intravenous antibiotic therapy for treating chest exacerbations in people with cystic fibrosis. SEARCH STRATEGY: We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register which comprises references identified from comprehensive electronic database searches, handsearches of relevant journals, abstract books and conference proceedings. Most recent search of the Group's Cystic Fibrosis Trials Register: February 2008. SELECTION CRITERIA: Randomised and quasi-randomised controlled trials comparing different durations of intravenous antibiotic courses for acute respiratory exacerbations in people with CF, either with the same drugs at the same dosage, the same drugs at a different dosage or frequency or different antibiotics altogether, including studies with additional therapeutic agents. DATA COLLECTION AND ANALYSIS: No eligible trials were identified. MAIN RESULTS: No eligible trials were identified. AUTHORS' CONCLUSIONS: There are no clear guidelines on the optimum duration of intravenous antibiotic treatment. Duration of treatment is currently based on unit policies and response to treatment. Shorter duration of treatment should improve quality of life and compliance; result in a reduced incidence of drug reactions; and be less costly. However, this may not be sufficient to clear a chest infection and may result in an early recurrence of an exacerbation. This systematic review identifies the need for a multicentre, randomised controlled trial comparing different durations of intravenous antibiotic treatment as it has important clinical and financial implications.

Genome size of human oral Treponema species by pulsed-field gel electrophoresis.

The genome sizes of seven strains of oral treponemes were determined using pulsed-field gel electrophoresis (PFGE). These strains represent members from six of the currently known cultivable oral treponeme groups. The PFGE fragments were digitally recorded and then quantitated using GIMP v 1.2, an image manipulation program. The results show that the six oral treponeme genomes are comparable in size, ranging from approximately 2.2 to 2.5 Mbp. The genome sizes of these strains are 20-25% smaller than Treponema denticola strains, which have genome sizes of approximately 2.8-3.0 Mbp.

The development of immunoassays to four biological threat agents in a bidiffractive grating biosensor.

A critical need exists for a field deployable biosensor to detect environmental infectious agents in collected air samples rapidly, with sensitivity and specificity approaching that of standard laboratory procedures. The ideal sensor would analyze unknown samples in minutes, have programmable operation for unattended sample analysis, and be capable of multiple agent analysis for a number of agents. The goal of this project was to further the development of the bidiffractive grating biosensor (BDG) created through collaboration between Battelle Memorial Institute (BMI), Hoffman LaRoche (HLR), and the Naval Medical Research Command (NMRC). This manuscript details the development, optimization, and evaluation of this device as a potential field deployable biosensor. Well-characterized immunochemical reagents developed by the Biological Defense Research Department (BDRD) at NMRI were employed to develop assays in the BDG. These results were compared to those obtained with antigen capture enzyme linked immunosorbent assays (ELISAs). Four separate antigens were evaluated: Staphylococcus aureus enterotoxin B (SEB), ricin (RIC), Francisella tularensis (FT), and Clostridium botulinum toxin (BOT).

Adverse behavioral effects in individuals with mental retardation and mood disorders treated with carbamazepine.

The incidence of carbamazepine-associated behavioral side effects in 65 individuals with mental retardation and additional seizure and/or psychiatric or behavioral disorders was evaluated. We identified 6 patients (9.2%) who experienced medication side effects, ranging from irritability to mania. Four of the 20 patients (20%) who received carbamazepine purely for treatment of a behavioral or psychiatric disorder experienced medication side effects, whereas none of the 21 patients treated for an isolated seizure disorder experienced similar effects. This difference was statistically significant, p less than .05. The incidence of behavioral side effects of medication was not associated with age, sex, or serum carbamazepine level. The chemical structure and mechanism of carbamazepine use in various disease processes were discussed.

Direct effects of thymopentin (Arg-Lys-Asp-Val-Tyr) on cholinergic agonist-induced slow inactivation of nicotinic acetylcholine receptor function.

The effects of thymopentin (TP-5) on the cholinergic agonist-induced inactivation of function (desensitization) of the nicotinic acetylcholine receptor (nAChR) were explored using two systems, 1) Torpedo californica electroplax nAchR reconstituted into phospholipid vesicles and 2) T. californica nAChR expressed, in Xenopus laevis oocytes, from in vitro synthesized RNA transcripts. The pentapeptide did not modify the equilibrium binding of 125I-alpha-bungarotoxin, but toxin rate binding assays in the presence of the cholinergic agonist carbamylcholine (Carb) revealed that it shortened the time course of the Carb-induced nAchR transition to the high affinity, desensitized state. Thymopentin (but not thymosins alpha 1 and beta 4) accelerated the slow inactivation of nAchR-mediated 86Rb+ influx, as measured by the first-order decrease in the Carb-induced 86Rb+ transport into the reconstituted vesicles. The decay of the acetylcholine-induced current from Torpedo receptor expressed in oocytes was also accelerated by TP-5. The pentapeptide had no ion channel-blocking or agonist activity of its own and exhibited a requirement for Ca2+ to express its effects. On the basis of these results, it is proposed that TP-5 has a direct effect on the nAChR, resembling that of noncompetitive blockers, as opposed to an indirect mechanism of action via the activation of specific metabolic pathways.

Genetics of mandible form in the mouse.

The underlying determination of phenotypic variability and covariability is described for 14 traits that define the morphological size and shape of the mature mouse mandible. Variability is partitioned into components due to direct additive and dominance genetic effects, indirect maternal additive genetic effects, genetic covariance between direct additive and indirect maternal additive effects and common and residual environmental effects. Multivariate analyses of the dimensionality of genetic variability indicate several complex and independent genetic components underlie the morphological form of the mandible. The multidimensional nature of the genetic components suggests a complex picture with regard to the consequences of selection on mandibular form.

Genetic analysis of size-scaling patterns in the mouse mandible.

The relationship between multidimensional form of the adult mouse mandible and body size is examined from an ontogenetic perspective. The origin and ontogeny of phenotypic correlations are described in terms of genetic and environmental covariance patterns between adult skeletal morphology and growth in body weight. Different ontogenetic patterns are observed in the genetic correlations, and these can be related to the developmental as well as the functional aspects of mandibular form. The quantitative genetic aspects of craniomandibular growth and morphogenesis are explored, together with an examination of the impact of ontogenetic changes in the genetic variance-covariance structure on morphogenetic integration and evolution by selection.

Effects of the muscular dysgenesis gene on developmental stability in the mouse mandible.

Muscular dysgenesis (mdg) is an autosomal recessive gene in mice affecting primarily the skeletal musculature. mdg/mdg mice exhibit developmental arrest of myogenesis and degenerative changes in all skeletal muscles. In addition, there are pronounced abnormalities in skeletal traits, including the shape of the skull and mandible. Herein, we examine the phenotypic consequences of a single mdg allele in the heterozygous condition (+/mdg) on the size, shape, and developmental stability in 14 osteometric traits from the mouse mandible. Developmental stability in the mandible is measured by fluctuating asymmetry in bilateral traits. There are no statistically significant differences in the size or shape of the mandible between +/+ and +/mdg mice. However, compared to +/+ mice, +/mdg individuals exhibit less developmental stability for several mandible traits. The more unstable traits include height at the mandibular notch, height at the incisive process, condyloid width, height and area of the coronoid process, and size of the tooth-bearing region. All of these latter traits are closely associated with areas of muscle attachment and/or the muscular dysgenesis phenotype, suggesting that the presence of a single mdg allele is sufficient to alter developmental pathways. Traits not showing significantly increased instability in +/mdg mice bear no clear relationship to either muscle attachment areas or to the mdg/mdg phenotype.

Immunologic abnormalities in two patients with pulmonary hyalinizing granuloma.

Pulmonary hyalinizing granuloma (PHG) is a disease of slowly enlarging pulmonary nodules made up of dense bundles of collagen accompanied by an infiltrate of chronic inflammatory cells. The etiology is unknown. Although it has been suggested that the lesions represent an exaggerated immune response to unidentified agents, results of a detailed immunologic work-up of these patients have not been published. This report presents the laboratory findings of two patients with biopsy-proven PHG who have been followed four and eighteen years. Autoantibodies were detected (antinuclear antibody, rheumatoid factor, and positive antiglobulin tests), although clinically there was no evidence of a specific collagen-vascular disorder. Both patients had elevated levels of circulating immune complexes. These data suggest that immune complex mechanisms may be important in the pathogenesis of PHG.