Repetitive dynamic matrix control for systems with periodic specifications.

This paper proposes a Repetitive Dynamic Matrix Control (RDMC) for systems with periodic specifications. The new algorithm is able to track periodic references and reject repetitive disturbances with a known period based on a modified prediction error. A repetitive version of the Generalized DMC (GDMC) is also proposed such that it can be applied to control open-loop unstable systems. Only the step-response coefficients are required to describe the dynamical system such that the RDMC preserves the modeling simplicity of the Dynamic Matrix Control (DMC). The proposed solution can be interpreted as an extension of the DMC for repetitive control applications. A data-driven filter design is proposed in order to ensure null prediction steady-state error in the presence of periodic disturbances even for unstable open-loop systems. Two case studies are presented to show the usefulness of the proposed strategy for control systems with periodic specification and to illustrate the typical advantages and drawbacks of the proposed repetitive control extension of the DMC algorithm.

A Generalised Dynamic Matrix Control for unstable processes based on filtered predictions.

This paper presents a Generalised Dynamic Matrix Control (GDMC) algorithm that can be used to control open-loop unstable processes. In contrast to the Dynamic Matrix Control (DMC), the GDMC is able to provide internally stable predictions due to a generalised filtered approach. The conditions to achieve internal stability are shown and a new data-driven filter design procedure is proposed. Two simulation case studies are presented to illustrate the usefulness of the GDMC.

Effects of Resistance Training With Machines and Elastic Tubes on Functional Capacity and Muscle Strength in Community-Living Older Women: A Randomized Clinical Trial.

The aim of the present study is to compare the effects of 12 weeks of resistance training with machines and elastic tubes on functional capacity and muscular strength in older women aged 60 years or over. The participants were randomized into two groups: a machine group (n = 23) and an elastic group (n = 20). They performed 12 weeks of progressive resistance training, twice a week, with similar exercises. Outcomes were assessed at three time points: baseline, postintervention, and 8 weeks after the end of the training. A significant intragroup effect was demonstrated for both groups at postintervention on functional tests and muscle strength. For the functional reach test and elbow flexion strength (180°/s), only the machine group demonstrated significant intragroup differences. No differences were observed between groups for any outcome. At the 8-week follow-up, functional capacity outcome values were maintained. The muscle strength outcome values decreased to baseline scores, without differences between groups.

Information without knowledge: the effects of Internet search on learning.

The Internet has radically shifted how people access information. Instead of storing information internally, increasingly, people outsource to the Internet and retrieve it when needed. While this is an efficient strategy in many ways, its downstream consequences remain largely unexplored. This research examines how accessing online information impacts how people remember information in a learning context. Across five experiments, participants studied for a quiz either by searching online to access relevant information or by directly receiving that same information without online search. Those who searched the Internet performed worse in the learning assessment, indicating that they stored less new knowledge in internal memory. However, participants who searched the Internet were as confident, or even more confident, that they had mastered the study material compared to those who did not search online. We argue that, by making information retrievability salient, Internet search reduces the likelihood of information being stored in memory. Further, these results suggest that searching online leads to the misattribution of online information to internal memory, thus masking the Internet-induced learning deficits.

Predictive ESO-based control with guaranteed stability for uncertain MIMO constrained systems.

In this paper, a novel predictive Extended State Observer (ESO)-based discrete controller with guaranteed input-to-state stability is developed. Predictive controllers based on ESOs are gaining acceptance for regulating MIMO systems with disturbances, uncertainties or actuator constrains. However, there is an important concern about this control structure regarding its closed-loop stability; a key property that is not strictly guaranteed with the most part of the previous formulations. This paper shows that -under the same assumptions that are normally taken in the ESO literature- a predictive ESO-based controller that is proved to be input-to-state stable can be easily constructed by adding two fixed terms in the cost-index definition. A simulation case study of the glucose control in patients with type-1 diabetes is additionally given in order to illustrate the main advantages of this control structure.

Recognizing and Trusting Persuasion Agents: Attitudes Bias Trustworthiness Judgments, but not Persuasion Detection.

People rely on intuitive knowledge about persuasion to cope with persuasion attempts motivated by self-interest. Because this knowledge associates persuasive intent with low trustworthiness, identifying the communicator as an agent with ulterior motives tends to reduce trust in the communicator. Three studies suggest that the extent to which people call on this association to assess a persuasion agent depends on whether the agent's message challenges or reinforces their prior attitudes. Challenged attitudes motivate people to use the negative association between persuasive intent and trustworthiness, whereas reinforced attitudes lead people to neglect it. However, prior attitudes do not affect people's capacity to detect cues of ulterior motives and develop an awareness of the persuasive intent. Thus, recipients of persuasive messages that support their prior beliefs trust persuasion agents despite being aware of the agents' ulterior motives. This seems to be a byproduct of people's motivation to preserve a sense of self-integrity.

New simple approach for enhanced rejection of unknown disturbances in LTI systems with input delay.

This work proposes the extension of the simplified filtered Smith predictor (SFSP) for state-space systems to improve rejection of matched and unmatched unknown disturbances in LTI systems with input delay. The proposed structure is simpler than others recently proposed in the literature and can be applied to continuous-time or discrete-time systems. Furthermore, it allows improving rejection of both matched and unmatched disturbances, while also enhancing noise attenuation and robustness characteristics. Finite spectrum assignment (FSA) based implementation is used in order to guarantee the internal stability of the proposed controller. Simulation and experimental results are used to show the usefulness of the proposal.

Simplified filtered Smith predictor for MIMO processes with multiple time delays.

This paper proposes a simplified tuning strategy for the multivariable filtered Smith predictor. It is shown that offset-free control can be achieved with step references and disturbances regardless of the poles of the primary controller, i.e., integral action is not explicitly required. This strategy reduces the number of design parameters and simplifies tuning procedure because the implicit integrative poles are not considered for design purposes. The simplified approach can be used to design continuous-time or discrete-time controllers. Three case studies are used to illustrate the advantages of the proposed strategy if compared with the standard approach, which is based on the explicit integrative action.

Unified dead-time compensation structure for SISO processes with multiple dead times.

This paper proposes a dead-time compensation structure for processes with multiple dead times. The controller is based on the filtered Smith predictor (FSP) dead-time compensator structure and it is able to control stable, integrating, and unstable processes with multiple input/output dead times. An equivalent model of the process is first computed in order to define the predictor structure. Using this equivalent model, the primary controller and the predictor filter are tuned to obtain an internally stable closed-loop system which also attempts some closed-loop specifications in terms of set-point tracking, disturbance rejection, and robustness. Some simulation case studies are used to illustrate the good properties of the proposed approach.

Use of polyhydroxybutyrate and ethyl cellulose for coating of urea granules.

Fertilizers contain essential nutrients for agricultural growth and development. However, most nitrogen fertilizers are substances with high solubility of ions and are very susceptible to leaching and volatilization. To minimize these losses, an alternative is the creation of a physical barrier around granules. One way is to coat granules with polymers. In the present work urea granules were coated with polyhydroxybutyrate and ethyl cellulose in various conditions in the presence of emulsifiers. The original granules and the final products were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy and thermogravimetry, to evaluate the surface morphology, the interaction between the granules and the coating, and the rates of mass change. The rates of urea release in distilled water were measured with a commercial enzyme kit. It is shown that those polymers are effective for coating of granules, leading to reduction of rates of urea dissolution in water.

Analysis of experimental errors in bioprocesses. 1. Production of lactobionic acid and sorbitol using the GFOR (glucose-fructose oxidoreductase) enzyme from permeabilized cells of Zymomonas mobilis.

The proper determination of experimental errors in bioprocesses can be very important because experimental errors can exert a major impact on the analysis of experimental results. Despite this, the effect of experimental errors on the analysis of bioprocess data has been largely overlooked in the literature. For this reason, we performed detailed statistical analyses of experimental errors obtained during the production of lactobionic acid and sorbitol in a system utilizing as catalyst the GFOR (glucose-fructose oxidoreductase) enzyme from permeabilized cells of the bacteria Zymomonas mobilis. The magnitude of the experimental errors thus obtained were then correlated with the process operation conditions and with the composition of the culture media used for bacterial growth. It is shown that experimental errors can depend very significantly on the operation conditions and affect the interpretation of available experimental data. More specifically, in this study, experimental errors depended on the nutritional supplements added to the cultivation medium, the inoculation process, and the reaction time, which may be of fundamental importance for actual process development. The results obtained also indicate, for the first time, that GFOR activity can be affected by the composition of the medium in which cells are cultivated.

Myositis ossificans traumatica of the medial pterygoid muscle: a case report.

In this report, we present a case of myositis ossificans traumatica (MOT) of the medial pterygoid muscle that had developed after mandibular block anesthesia administered for endodontic treatment of the lower right second molar, demonstrating typical features of this condition. MOT should be considered as a differential diagnosis when there is severe limitation of jaw opening and an associated trauma. Panoramic radiographs and axial and coronal computed tomography (CT) scans can effectively delineate the calcified mass. Other imaging studies that may be helpful include magnetic resonance imaging (MRI), bone scans, and ultrasound. As shown in our case, calcified masses were found in the right mandibular angle, which severely limited jaw opening. Some earlier reported cases of MOT were treated by extraoral surgical approaches with complete removal of the evolving muscle. The aim of this case report is to present only the diagnostic imaging aspects of myositis ossificans traumatica.

Hyaluronidase binds differently DPPC, DPPS or GlcNAc-bearing glycolipid biomimetic monolayers.

Bovine testis hyaluronidase (btHyal) had been shown to have direct effects on cancer cells and to be a useful adjuvant in several medicines. Furthermore this enzyme had been found to be membrane-associated. Thus, in this work, the interactions between btHyal and membranes were analyzed by using lipid monolayers at the air-water interface as a biomimetic membrane system. This allowed us to define the btHyal interactions with two residues of hyaluronic acid (a btHyal substrate), GlcNAc and carboxylic group, which are present in cholesteryl-triethoxy-N-acetylglucosamine (Chol-E3-GlcNAc) and in DPPS, respectively. btHyal bound preferentially Chol-E3-GlcNAc monolayers and showed a decreasing affinity for Chol-E3-GlcNAc-DPPC monolayers containing decreasing amount of glycolipid, suggesting a crucial role of the glycolipid GlcNAc. Furthermore the significant btHyal binding to DPPS was not affected by the presence of free GlcNAc in the subphase. These results and the absence of significant binding of btHyal to pure DPPC monolayer suggest that the protein interacts with the lipid monolayer by mimicking the enzyme-substrate interactions or by electrostatic interactions.

Structural stability of myoglobin in organic media.

The structural stability of metmyoglobin in organic solvents and cosolvents was investigated aiming the choice of a suitable medium to perform its dissolution with maintenance of the native folding. The spectroscopic behavior of metmyoglobin solution in UV-Visible and circular dichroism was used to evaluate the solubility and the secondary structure. The results were dependable of the chemical structure of the organic compounds, their polarity and content, in the case of cosolvents. Protic solvents showed better ability than the aprotic ones for the biomolecule dissolution, since they are able to establish hydrogen bonds. Solvents with high polarity usually damage the secondary structure of the protein. Myoglobin was dissolved in pure methanol, ethylene glycol and glycerol. The secondary structure was retained in some extent. The controlled addition of sodium dodecyl sulfate to myoglobin aqueous solution changed the surface moiety of the protein. The complex was extracted to hexane with efficiency of 77%.

Interfacial behaviour of bovine testis hyaluronidase.

The interfacial properties of bovine testicular hyaluronidase were investigated by demonstrating the association of hyaluronidase activity with membranes prepared from bovine testis. Protein adsorption to the air/water interface was investigated using surface pressure-area isotherms. In whichever way the interfacial films were obtained (protein injection or deposition), the hyaluronidase exhibited a significant affinity for the air/water interface. The isotherm obtained 180 min after protein injection into a pH 5.3 subphase was similar to the isotherm obtained after spreading the same amount of protein onto the same subphase, indicating that bovine testicular hyaluronidase molecules adopted a similar arrangement and/or conformation at the interface. Increasing the subphase pH from 5.3 to 8 resulted in changes of the protein isotherms. These modifications, which could correspond to the small pH-induced conformational changes observed by Fourier-transform IR spectroscopy, were discussed in relation to the pH influence on the hyaluronidase activity. Adding hyaluronic acid, the enzyme substrate, to the subphase tested the stability of the interfacial properties of hyaluronidase. The presence of hyaluronic acid in the subphase did not modify the protein adsorption and allowed substrate binding to a preformed film of hyaluronidase at pH 5.3, the optimal pH for the enzyme activity. Such effects of hyaluronic acid were not observed when the subphase was constituted of pure water, a medium where the enzyme activity was negligible. These influences of hyaluronic acid were discussed in relation to the modelled structure of bovine testis hyaluronidase where a hydrophobic region was proposed to be opposite of the catalytic site.

Hydrolysis of new phthalimide-derived esters catalyzed by immobilized lipase.

The last step of the production of four phthalimide-derived acids, designed to act as antiasthma drugs, was performed by enzymatic hydrolysis of the respective methyl or ethyl esters. The esters 4-ethyl-[2-(1,3-dioxo-1,3-dihydro- 2-isoindoylyl)]-phenoxyacetic methyl ester (PHT-MET), 4-ethyl-[2- (1,3-dioxo-1,3-dihydro-2-isoindoylyl)]-phenoxyacetic ethyl ester, 4-(1, 3-dioxo-1,3-dihydro-2-isoindoylyl)-phenoxyacetic ethyl ester, and 2-(1,3-dioxo-1, 3-dihydro-2-isoindoylyl)-phenoxyacetic ethyl ester were hydrolyzed by immobilized lipase. The enzymatic reaction could be used only to produce the desired 4-substituted compounds. The best result that was found to hydrolysis of PHT-MET, and, therefore, that ester was selected for optimization experiments in a three-phase system. Reactions were performed with solid biocatalyst (Lipozyme RM IM), organic solvent phase (ethyl acetate), and aqueous phase (saturated Na2CO3 solution). To optimize the reaction conditions, an experimental design optimization procedure was used. The variables studied were the amount of enzyme, the temperature, and the volume of the aqueous solution. Time course experiments were then performed for different initial enzyme concentrations (0.5, 0.9, and 1.4 UH/mL of solvent). The optimized reaction conditions found were 20 mg of Lipozyme (0.9 UH/mL solvent) and 5.0 mL of Na2CO3(sat) at 40 degrees C for 6 h.

7-day rescue therapy with ranitidine bismuth citrate after Helicobacter pylori treatment failure.

BACKGROUND: Quadruple rescue therapy requires a complex scheme with four drugs. AIM: To evaluate the efficacy of ranitidine bismuth citrate-tetracycline-metronidazole rescue regimen, and to compare two different metronidazole dose schemes. METHODS: Prospective multicentre study including proton-pump inhibitor + clarithromycin + amoxicillin failures. Rescue regimen included two 7-day treatment: (i) ranitidine bismuth citrate (400 mg b.d.)-tetracycline (500 mg q.d.s.)-metronidazole (500 mg t.d.s.; RTM1); or (ii) the same regimen but with metronidazole 250 mg q.d.s. (RTM2). Eradication was confirmed with (13)C-urea breath test. RESULTS: A total of 150 patients were included (58 RTM1, 92 RTM2). All patients but two (one in each group) returned after treatment. About 86% in group RTM1 and 95% in RTM2 correctly took all the medications (P = 0.076). Per-protocol eradication rates with RTM1 and RTM2 were 74 (95% CI: 60-84) and 69% (59-78). The intention-to-treat eradication rates were 64 (51-75) and 70% (59-78; P > 0.05). The type of regimen was not associated with eradication in the multivariate analysis. Adverse effects were more frequent with RTM1 (41%) than with RTM2 (30%; P > 0.05). CONCLUSION: Seven-day triple rescue therapy with ranitidine bismuth citrate-tetracycline-metronidazole is effective for Helicobacter pylori eradication, and represents an encouraging alternative to quadruple therapy, with the advantage of simplicity. The administration of metronidazole every 6 h (together with tetracycline), and at a low dose (250 mg), achieves similar efficacy and is probably associated with a better compliance and a lower incidence of adverse effects.

A potential complication of bi-level positive airway pressure after gastric bypass surgery.

BACKGROUND: Bi-level positive airway pressure (BIPAP) is a common treatment modality for patients with obstructive sleep apnea (OSA), especially in the morbidly obese population. To our knowledge, there have been no reports of any adverse effects of BIPAP on patients who undergo weight loss surgical procedures. METHODS: We report 2 patients who were treated with BIPAP in the postoperative period following open Roux-en-Y gastric bypass (RYGBP). Their clinical courses and outcomes are presented. RESULTS: The patients developed massive bowel distention following treatment with BIPAP and subsequently developed anastomotic leaks. CONCLUSION: BIPAP following RYGBP may not be a completely benign treatment modality. We advise caution and careful monitoring during the use of BIPAP after gastric bypass surgery.

One-week triple vs. quadruple therapy for Helicobacter pylori infection - a randomized trial.

BACKGROUND: Seven-day triple therapy including omeprazole, clarithromycin and amoxicillin has become the treatment of choice for Helicobacter pylori infection. However, 7 days of classical quadruple therapy combining omeprazole, tetracycline, metronidazole and bismuth may be an alternative to triple therapy. AIM: To compare triple vs. quadruple therapy for H.pylori eradication. METHODS: Three hundred and thirty-nine patients with peptic ulcer and H. pylori infection were included in the study. Patients were randomized to receive omeprazole, 20 mg, amoxicillin, 1 g, and clarithromycin, 500 mg, all b.d., or omeprazole, 20 mg b.d., tetracycline chloride, 500 mg, metronidazole, 500 mg, and bismuth subcitrate, 120 mg, all t.d.s. Cure was defined as a negative urea breath test at least 2 months after treatment. RESULTS: Per protocol and intention-to-treat cure rates were 86%[95% confidence interval (CI), 80-91%] and 77% (95% CI, 70-83%) for triple therapy, and 89% (95% CI, 82-93%) and 83% (95% CI, 76-88%) for quadruple therapy. No significant differences between the groups were found in the cure rates, compliance or side-effects. CONCLUSION: One-week triple and quadruple therapy show similar results when used as first-line eradication treatment.