Immobilization of Phytase Producing Probiotics in Shrimp Chitosan Cross-linked by Zinc Oxide Nanoparticles and Assay its Antibacterial Activity

Background and objective: Phytase is used in human and poultry additives. This enzyme is mostly produced by Aspergillus niger which is a plant pathogen. Phytase from probiotics is a good candidate for the food supplements.Materials and methods: Bacillus coagulans, as a probiotic, was used for phytase and phosphatase activities on phytin agar and Pikovskayas Agar. The sodium dodecyl sulfatepolyacrylamide gel electrophoresis and zymogram analyses of the extracted phytase enzyme were carried out. Probiotic cells with phytase activity were immobilized on chitosan extracted from shrimp shells and the efficiency was investigated and analyzed using scanning electron microscopy and Fourier transform infrared.Results and conclusion: In this study, Bacillus coagulans showed intracellular phytase activities from broken cells with Soluble Index of 2.5 on phytase specific media. Iron and zinc oxide nanoparticles accelerated the enzyme activity by 25%. Cells were precipitated using ZnO-chitosan nanoparticles and the enzyme activity was investigated on gels. Chelation of chitosan-metal ion increased the positive charge density of chitosan which was expected to enhance adsorption of zinc and teichoic acid on Gram-positive Bacillus coagulans; approved by SEM and FTIR. Cells immobilized on ZnO-chitosan promoted the enzyme activity by 28,800 U ml-1 gel. The entrapped cells were resistance to high temperature and pH. This complex not only included activities against Streptococcus agalactiae, but also dissolved insoluble phosphate and phytin, which has made this complex a good candidate for use as additive in human and animal foods.Conflict of interest: The authors declare no conflict of interest

Upravljanje pozicijom električki pokretanog brzog površinskog vozila korištenjem unaprijedne projekcije izlazne povratne veze

Robust tracking is an issue of vital practical importance to the ship This paper addresses the design of a trajectory tracking controller for fast underactuated ships in the presence of model uncertainties without velocity measurements in the yaw and surge directions. An observer-based trajectory tracking controller is proposed for the fast underactuated ship model. Then, the dynamic surface control approach is effectively exploited to propose a tracking controller considering the actuator dynamics. Adaptive robust techniques are also adopted to cope with the parametric and non-parametric uncertainties in the fast underactuated ship model. A Lyapunov-based stability analysis is utilised to guarantee that tracking and state estimation errors are uniformly ultimately bounded. Simulation results are presented to illustrate the feasibility and efficiency of the proposed controller.Robusno praćenje je pitanje od vitalnog praktičnog značaja za brod. Ovaj se rad bavi projektiranjem regulatora za praćenje trajektorije za brze podaktuirane brodove s modelima nesigurnosti bez mjerenja brzine u smjerovima zaošijanja i uzdužnog napredovanja. Regulator za praćenje putanje zasnovan na observeru predložen je za brz podaktuiran model broda. Upravljanje površinskom dinamikom je učinkovito iskorišteno kako bi se predložio regulatora za praćenje trajektorije s obzirom na dinamiku aktuatora. Također su primjenjene adaptivne robusne tehnike kako bi se nosile sa parametarskim i neparametarskim nesigurnostima u modelu brzog podaktuiranoga broda. Analiza stabilnosti temeljena na Lyapunovu se koristi kako bi se zajamčilo da se pogreške praćenja i estimacije stanja adaptivne robusne tehnike također usvajaju kako bi se nosile s parametarskim i neparametarskim nesigurnostima u brzom neaktivnom brodskom modelu. Analiza stabilnosti temeljena na Lyapunovu se koristi kako bi se zajamčilo da su pogreške praćenja i procjene stanja jednoliko konačno ograničene. Prikazani su simulacijski rezultati koji ilustriraju izvedivost i učinkovitost predloženog regulatora

Predicting sensory perceptions of thickened solutions based on rheological analysis

The sensory perceptions of sweetened, flavoured and thickened solutions prepared from xanthan, dextran, sucrose and banana flavour were evaluated and correlated to rheological parameters. The primary aim of this research was to evaluate the relevance of viscosity measured at low shear or at high shear for predicting sensory perceptions. Additionally considered were extensional viscosity estimated from filament thinning experiments and complex shear viscosity. The design of experiments included two groups of 5 samples matched at low shear rate and high shear rate, respectively. Mouthfeel perceptions were well correlated to low shear viscosity, however, including high shear viscosity or extensional viscosity as an additional model parameter improved the predictive quality of the models for thickness, stickiness and mouth coating. Stickiness and mouth coating were better correlated to extensional viscosity than low shear viscosity, although a model including both parameters predicted stickiness and mouth coating best. The complex viscosity at 100 rad/s was also highly correlated to the perception of thickness. Since correlations were not improved over steady shear parameters, complex viscosity was not considered in models based on more than one rheological parameter. Flavour was also scored during sensory evaluation and sweetness and overall flavour were highly correlated. The results of this study have highlighted that there is no single rheological parameter that will ultimately correlate to a range of mouthfeel perceptions. For certain mouth feel perceptions a model comprising shear and extensional rheological parameters will have higher predictive power than a model solely based on shear rheological parameters

Intelligent Control of Quadrotor Unmanned Helicopter in Hovering Mode

A Quadrotor helicopter is an unmanned aerial vehicle (UAV). This vehicle has attracted lots of researchers’ attention because of its unique abilities such as being an under-actuated system, vertical take-off and landing, spot movement, more degree of freedom (DOF) and military and non- military functions. Because of nonlinear and complex dynamic, modeling and controlling this vehicle is one of the most challenging areas in control engineering. In this paper modeling of a Quadrotor will be described using Newton-Euler equations. Stabilizing and controlling of altitude and its attitude are done by three controller including classic PID, Fuzzy- PID and Neural- Fuzzy based on PID. Performances of these controllers are analyzed in the presence of disturbances and mass uncertainties. The main aim of this paper is designing an intelligent PID algorithm which is made by combining fuzzy logic and neural system and it will introduce a Neural- Fuzzy controller which is based on PID. Simulation results are presented by MATLAB software

One DOF Robot Manipulator Control Through Type-2 Fuzzy Robust Adaptive Controller

In this article, the one DOF robot manipulator control is assessed through second type robust fuzzy-adaptive controller. The objective is to obtain a tracking path with appropriate accuracy. The stability of the closed loop system is verified through Lyapunov stability theory and the efficiency of tracking is analyzed subject to the constraints and uncertainty. In order to design the fuzzy controller a set of if-then fuzzy rules are considered which describe the system input-output behavior. Simulation and the results of the experiments on the one DOF robots indicate the effectiveness of the proposed methods

The Role of median nerve terminal latency index in the diagnosis of carpal tunnel syndrome in comparison with other electrodiagnostic parameters

Background: Carpal tunnel syndrome (CTS) considers the most common compression neuropathy, which nerve conduction studies (NCSs) used for its detection routinely and universally. This study was performed to determine the value of the median TLI and other NCS variables and to investigate their sensitivity and specificity in the diagnosis of CTS. Materials and Methods: The study was carried out among 100 hands of healthy volunteers and 50 hands of patients who had a positive history of paresthesia and numbness in upper extremities.Information including age, gender, and result of sensory and motor nerve conduction velocity (MNCV), peak latency difference of median and ulnar nerves of fourth digit (M4-U4 peak latency difference), and TLI were recorded for analysis. Sensitivity and specificity of electro diagnostic parameters in the diagnosis of CTS was investigated. Results: Normal range of the median nerve TLI was 0.43 ± 0.077. There was no significant difference between two groups for MNCV means (P = 0. 45). Distal sensory latency and distal motor latency (DML) of median nerve and fourth digit median-ulnar peak latency differences (PM4-PU4) for CTS group was significantly higher (P < 0.001) and mean for sensory nerve conduction velocity was significantly higher in control group (P < 0.001). The most sensitive electrophysiological finding in CTS patients was median TLI (82%), but the most specific one was DML (98%). Conclusion: Although in early stages of CTS, we usually expect only abnormalities in the sensory studies, but TLI may better demonstrate the effect on median nerve motor fiber even in mild cases of CTS

Fuzzy Adaptive Control for Trajectory Tracking of Autonomous Underwater Vehicle

In this paper, the problem of the position and attitude tracking of an autonomous underwater vehicle (AUV) in the horizontal plane, under the presence of ocean current disturbances is discussed. The effect of the gradual variation of the parameters is taken into account. The effectiveness of the adaptive controller is compared with a feedback linearization method and fuzzy gain control approach. The proposed strategy has been tested through simulations. Also, the performance of the propos-ed method is compared with other strategies given in some other studies. The boundedness and asymptotic converge-nce properties of the control algorithm and its semi-global stability are analytically proven using Lyapunov stability theory and Barbalat’s lemma

A novel approach to 6-DOF adaptive trajectory tracking control of an AUV in the presence of parameter uncertainties

In this paper, the trajectory tracking control of an autonomous underwater vehicle (AUVs) in six-degrees-of-freedom (6-DOFs) is addressed. It is assumed that the system parameters are unknown and the vehicle is underactuated. An adaptive controller is proposed, based on Lyapunov׳s direct method and the back-stepping technique, which interestingly guarantees robustness against parameter uncertainties. The desired trajectory can be any sufficiently smooth bounded curve parameterized by time even if consist of straight line. In contrast with the majority of research in this field, the likelihood of actuators׳ saturation is considered and another adaptive controller is designed to overcome this problem, in which control signals are bounded using saturation functions. The nonlinear adaptive control scheme yields asymptotic convergence of the vehicle to the reference trajectory, in the presence of parametric uncertainties. The stability of the presented control laws is proved in the sense of Lyapunov theory and Barbalat׳s lemma. Efficiency of presented controller using saturation functions is verified through comparing numerical simulations of both controllers