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In this study, jujube polysaccharide (JP) was extracted from Ziziphus jujuba cv. Jinsixiaozao and sulfated JP (SJP) was prepared. The optimum preparation conditions were as follows: reaction temperature 75°C, reaction time 1 h, ratio of chlorosulfonic acid-to-pyridine ( VCSA/ VPyr) 1. The degree of substitution of SJP was 0.664 ± 0.014. JP and SJP were typical heteropolysaccharides, which were composed of rhamnose, arabinose, xylose, mannose, glucose, and galactose, but the molar ratio of monosaccharides was different. Fourier transform infrared spectra showed that JP was sulfated successfully. Compared with JP, the molecular weight of SJP increased to 3.17 × 105 Da, its water solubility increased significantly, and its viscosity decreased significantly. When the microstructure of SJP was examined, it was found that the surface of the polysaccharides became loose and porous after sulfation. SJP had a higher hydroxyl radical scavenging activity than the unsulfated polysaccharide. Moreover, sulfation enhanced the antibacterial activity of the polysaccharides against Escherichia coli and Bacillus subtilis. Therefore, sulfation is an effective way to improve the biological activity of the polysaccharide, and SJP can be used as a potential antioxidant and antimicrobial agent in the field of food and medicine.

Genetic algorithms often cause premature convergence and can not give out global optimality in solving UC problems,while the simulated annealing algorithm shows better performance in accepting new solutions.By introducing annealing algorithm to the evaluation functions and the selection manipulation,the selection manipulation and the global convergency can be improved.Using decimal coding with no decoding,both the calculation error and time for calculation can be reduced.The example shows that this hybrid algorithm can improve the economic performance of UC scheme while various restrictions for security and reliability are still satisfied.

The levitation between high temperature superconductors (HTSs) and permanent magnets (PMs) has been applied to the flywheel energy storage systems and magnetic bearing systems for the last nearly twenty years. The interaction forces acting on the levitating body are calculated by the modified frozen-image method. The magnetic dipoles are equivalent to Amperian current loops. The current intensity in loops changes linearly when the PM moves. Under the zero field cooling condition, the expression of vertical force is obtained when the PM traverses vertically, and when the PM traverses horizontally, the expressions of vertical and horizontal forces are obtained. Those expressions of vertical and horizontal forces are gained by calculating the forces between current loops and using superposition theorem of vector. The calculations agree well with the previous experimental data, which means that the deductions of the expressions are reliable.

Based on principles of viscoelastic mechanics and hydrostatics, this paper expounds the dynamic mechanism of bulk strain response to exterior forces in the confined aquifers and derives the theoretical formula of well water level observation system, which shows that the system is an amplification link at zero order and its transfer function is a constant, then figures out the theoretical scale unit value range allowed in the well water level system with the porosity of aquifers equivalent to zero or 1. Considering that the system is a natural bulk strain gauge, the amplitude ratio (tidal factor) derived by the Venidikov harmonic analysis can be regarded as the transfer function (sensitivity) of a well. Owning to that the semidiurnal wave is the major object of well water level observation and M2 wave constitutes the majority of semidiurnal waves, it is advisable to take the reciprocal sensitivity of M2 wave as the scale unit of a well water level system. On this basis, the paper utilizes the well water level minute-values at 5 Fujian wells in May 2008 to compute the coseismic striking steps caused by Wenchuan M8.0 earthquake, and the result show that the amplitude of the coseismic steps and the bulk strain earth tides reach to the same order of magnitude as much as 10–7 ~ 10–8.

A remote control system has been developed to deliver stimuli into the rat brain through a wireless micro-stimulator for animal behavior training. The system consists of the following main components: an integrated PC control program, a transmitter and a receiver based on Bluetooth (BT) modules, a stimulator controlled by C8051 microprocessor, as well as an operant chamber and an eight-arm radial maze. The micro-stimulator is featured with its changeable amplitude of pulse output for both constant-voltage and constant-current mode, which provides an easy way to set the proper suitable stimulation intensity for different training. The system has been used in behavior experiments for monitoring and recording bar-pressing in the operant chamber, contriolling rat roaming in the eight-arm maze, as well as navigating rats through a 3D obstacle route. The results indicated that the system worked stably and that the stimulation was effective for different types of rat behavior controls. In addition, the results showed that stimulation in the whisker barrel region of rat primary somatosensory cortex (SI) acted like a cue. The animals can be trained to take different desired turns upon the association between the SI cue stimulation and the reward stimulation in the medial forebrain bundle (MFB).

The anticancer activity of anti-bacterial cecropins makes them potentially useful as peptide anti-cancer drugs. We used the cell-attached patch to study the effect of cecropin B (CB; having one hydrophobic and one amphipathic alpha-helix) and its derivative, cecropin B3 (CB3; having two hydrophobic alpha-helices) on the membrane of Ags cancer cells. Application of 10-60 microM CB onto the membrane of the cancer cell produces short outward currents. Comparative study with CB3, which induces no outward currents, shows that the amphipathic group of CB is necessary for the pore formation. The results provide a rationale to study the cell-killing activity of antimicrobial peptides at the single cancer cell level.

Based on a generalized variational principle for magneto-thermo-elasticity, a theoretical model is proposed to describe the coupled magneto-thermo-elastic interaction of soft ferromagnetic plates. Using the linearized theory of magneto-elasticity and perturbation technique, we analyze the magneto-elastic and magneto-thermo-elastic instability of simply supported ferromagnetic plates subjected to thermal and magnetic loadings. A coupled nonlinear finite element procedure is developed next to simulate the magneto-thermo-elastic behavior of a ferromagnetic plate. The effects of thermal and magnetic fields on the magneto-thermo-elastic bending and buckling is investigated in some detail.

This paper presents an analysis of buckling/snapping, bending and post-buckling/snapping behaviors of magneto-elastic–plastic interaction and coupling for soft ferromagnetic beam-plates with geometrically nonlinear deformation and unmovable simple supports at the ends of the plates. Based on the expression of magnetic force from the variational principle of ferromagnetic plates, the theory of thin plates with the nonlinear deformation of van Karman’s type, and the Mises yield criterion and the increment theory for plastic deformation, here, we establish a numerical code to quantitatively simulate the behaviors of the nonlinearly multi-coupling problems by the finite element method. Along with that the phenomena of buckling, bending, and post-buckling/snapping, or the characteristic curve of deflection versus magnitude of applied magnetic fields are numerically displayed, the critical values of buckling/snapping and yield magnetic fields, and the expansibility of plastic region after the plates undergo plastic deformation with increasing of the applied magnetic fields, as well as the evolvement of deflection configuration of the plate are numerically obtained in a case study.

Phase-locking is an important encoding mode in the hippocampal region of brain where neuronal firing concentrates on a certain phase of the periodic field potential, especially θ rhythm. It can be observed during many behaviors while the locked-phase varies accordingly. In this study, the changes of neuronal phase-locking induced by somatosensory stimulation of tail-clamping were investigated. The local field potential and spike signals were recorded in hippocampal CA1 region of anesthetized rats with microelectrode array. The phase-locking relationship was analyzed with Raleigh test and spike-phase histogram. The results showed that during spontaneous activity, 3 of 20 examined neurons were phase-locking to the θ rhythm of the field potential. However, during the tail clamping periods, the number of phase-locking neurons increased from 3 to 8, and the mean locked-phase shifted towards the negative peak of the field potential cycle, which became θ rhythm dominated. These findings suggest that the hippocampus may encode somatosensory information with the phase-locking neurons and by shifting their locked-phases.

In this paper, a theoretical model is developed to describe a magnetic force arisen from an interaction between the nonlinear magnetization of structures made of soft ferromagnetic materials and an applied magnetic field in which the structures are placed. The fundamental equations of ferromagnetic structures in a magnetic field involve twofold nonlinearity since the interaction between the magnetic field and the deformation of the structure leads to the equations nonlinear besides the nonlinear magnetization. Magnetoelastic bending and buckling of a simply supported rectangular plate, as an example, are investigated by these fundamental equations. A numerical programme combined the 3D FEM with the iterative method is suggested to quantitatively simulate the magnetoelastic behavior of the plate. It is found that the characteristics of magnetoelastic bending and instability for the plates having nonlinear magnetization are distinctive from those of the plates having linear magnetization.

This paper presents a non-linear effect of magnetic damping of conducting structures moving in magnetic fields. For this purpose, a simply typical model, i.e. a non-conducting and non-magnetizable cantilevered beam-plate with end coils in a transverse magnetic field, is employed in the discussion of this paper. After the second power of the rotation at the free end is taken into account, a nonlinear relation between the magnetic couple exerted on the coils and the rotation is gained. A formula of the effective damping factor for the nonlinear dynamic system with electromagneto–mechanical interaction is obtained by applying the method of energy balance. The numerical results show that the effective damping factor is changeable with the amplitude of the beam-plate or time. The larger the amplitude, the bigger the effective magnetic damping.

Based on a theoretical model of the magnetoelastic interaction of superconducting coils from the theory of curved beams and the Biot–Savart law, the dynamic behavior of the current-carrying coils disturbed by a pulse current is investigated in this paper. The initial boundary-value equations of the problem are numerically solved by applying the finite difference method for spatial part and the Wilson- θ method for time part. The numerical responses exhibit that the equilibrium position of the vibration of the deformable coil may sometimes jump from one to another, which is referred to as the magnetoelastic dynamic instability of the coil. It is found that the dynamic stability is mainly dependent upon the magnitudes of the steady working current, the peak and the duration of the pulse current. The ranges of these parameters for the magnetoelastic dynamic stability of the coils are searched in detail.

This paper presents numerical analyses on dynamic behavior of a maglev vehicle with a control system moving on flexible guideways. The vehicle is simplified as a body with the primary and the secondary suspension parts and has five-degree-of-freedom (d.o.f.). So, its five kinds of motions, i.e., heave, sway, pitch, roll, and yaw motions are considered. The numerical results show that the dynamical characteristics of a coupling maglev vehicle/guideway system are different from those of the uncoupling system in which the deformation of the guideways is neglected. For the coupling system, one kind of disturbances in the five motions may excite several other kinds of moving responses. Both the disturbances and the control parameters have an influence on the stability of the dynamical system. In order to make the system stable, regions for the disturbance of heave motion or/and sway motion and the control parameters are numerically searched in detail.

A theoretical study of bending and buckling of ferroelastic plates in the presence of magnetic fields is carried out based on the model that takes into account the nonlinear field-structure interaction. The resultant force system derived from the interaction between magnetic fields and ferromagnetic materials is composed of the body force only. Using this model, the bending and buckling problems of a cantilevered ferromagnetic plate and simply supported rectangular plates in transverse and oblique magnetic fields are investigated with the aid of a numerical approach. Numerical results reveal some interesting features of magnetoelastic bending and buckling phenomena due to the nonlinear nature of the field-structure interaction.

Small free vibrations of a thin elastic clamped circular plate under a compressive thrust applied at its edges is studied near the nonlinear static deformation state. Based on the solution of von Karman's plate equations for the static state of circular plates, the dynamic-eigenvalue or free-vibration problem is reduced to one of solving three algebraic equations leading to an analytic solution. This is achieved by introducing a coefficient of transformation related to the eigenfunctions and presenting the algebraic homogeneous equations in terms of the eigenvalues. The natural frequency versus the applied load is derived and plotted for various values of the load. The frequency of the small vibrations vanishes at the limit load. The advantage of the proposed analytic method lies in its ability to predict and describe the stability of the static equilibrium configuration and the postbuckling path.

Ferritic stainless steel has been considered for structural components such as first walls and blankets of fusion power reactors because the material shows low rates of irradiation swelling. Since it is magnetizable, the magnetoelastic interaction between magnetic field and deformation of the structures in a fusion reactor is so strong that their safety is of concern due to the magnetoelastic bending, buckling and magnetic damping, etc. Basic research of the magnetoelastic characteristics of ferromagnetic plate has been paid special attention by researchers. In this paper, the magnetoelastic bending and snapping are studied for a ferromagnetic plate in an oblique magnetic field. The theoretical model is based on the variational principle where the functional is employed as real total energy in the system including external work. The obtained expression of magnetic force on the plate is the same as that derived from the dipole model when the total magnetic field in the ferromagnetic medium is considered. In order to effectively solve the nonlinearly coupled interaction problem between magnetic field and mechanical deformation, a numerical program combining the finite element method for analyzing the magnetic field with the finite difference technique for finding out the bending deformation of the plate is employed to obtain the solution of magnetoelastic bending of a soft ferromagnetic plate. The numerical calculations are carried out for the typical example of a ferromagnetic cantilevered beam-plate in an oblique magnetic field. From the bending curves, that is the tip deflection versus applied magnetic fields, the critical magnetic field for the magnetoelastic snapping is predicted by the Southwell plot. The theoretical predictions show that the critical magnetic field decreases with the increase in incident angle of the oblique magnetic field. By the effect of incident angle on the magnetic buckling, the discrepancy between theoretical and experimental data can be explained well.

A new theoretical model for characterizing the magnetoelastic bending and buckling/snapping of superconducting coils is proposed on the basis of bending theory of curved beams and the Biot-Savart law. Both in-plane and out-of-plane bending coupled with axial extension and torsion about the centerline of the coil are considered in this theoretical study. After the closed form of general solutions to the homogeneous differential equations of the curved beam for a circular coil is analytically found, a numerical iterative technique from the difference method which is independent of the boundary conditions is chosen to obtain a set of particular solutions to the inhomogeneous equations of the problem. The initial parameter method is employed to determine integral constants and an iteration is chosen to solve the nonlinear interaction between the magnetic field and deformation of the coil. The magnetoelastic buckling/snapping current is predicted from the Southwell plot of the maximum transverse deflection of the deformed coil. The theoretical predictions are in excellent agreement with the existing experimental data, and show that there is a noticeable influence of the in-plane deformation on the critical value of magnetoelastic buckling/snapping current.

Dysfunction of inhibitory synaptic transmission can destroy the balance between excitatory and inhibitory synaptic inputs in neurons, thereby inducing epileptic activity. The aim of the paper is to investigate the effects of successive excitatory inputs on the epileptic activity induced in the absence of inhibitions. Paired-pulse orthodromic and antidromic stimulations were used to test the changes in the evoked responses in the hippocampus. Picrotoxin (PTX), γ-aminobutyric acid (GABA) type A (GABA(A)) receptor antagonist, was added to block the inhibitory synaptic transmission and to establish the epileptic model. Extracellular evoked population spike (PS) was recorded in the CA1 region of the hippocampus. The results showed that the application of PTX induced a biphasic change in the paired-pulse ratio of PS amplitude. A short latency increase of the second PS (PS2) was later followed by a reappearance of PS2 depression. This type of depression was observed in both orthodromic and antidromic paired-pulse responses, whereas the GABAergic PS2 depression [called paired-pulse depression (PPD)] during baseline recordings only appeared in orthodromic-evoked responses. In addition, the depression duration at approximately 100 ms was consistent with a relative silent period observed within spontaneous burst discharges induced by prolonged application of PTX. In conclusion, the neurons may ignore the excitatory inputs and intrinsically generate bursts during epileptic activity. The depolarization block could be the mechanisms underlying the PPD in the absence of GABA(A) inhibitions. The distinct neuronal responses to stimulations during different epileptic stages may implicate the different antiepileptic effects of electrical stimulation.

To evaluate the diagnostic value of full-field digital mammography for breast cancer.The clinical data and mammograms of 230 patients with breast diseases between January 2008 and July 2008 were collected and reviewed. Craniocaudal (CC) and mediolateral oblique (MLO) view mammograms were performed in all patients before surgery. Three experienced radiologists in breast imaging assessment analyzed and classified all the mammograms according to breast imaging reporting and data system (BI-RADS). The sensitivity, specificity and accuracy were evaluated according to their pathological diagnosis. The reasons resulting in false-negative and false-positive diagnosis were also analyzed.Of the 238 samples, 130 had a malignant breast tumors and 108 cases of benign breast lesions. One hundred and nine of the 130 malignant breast tumors were invasive ductal carcinoma. Fifty-seven of the 108 benign breast lesions were breast adenosis. Masses or masses with microcalcification were the most frequently seen signs of the malignant tumors, accounting for 40.8% and 20.8%, respectively. The sensitivity, specificity and accuracy of FFDM in detecting breast carcinoma were 90.8%, 87.0% and 89.1%, respectively. The false-negative signs including negative X-ray finding (5 cases) and focal asymmetric densities (4 cases). The false-positive signs were masses with spiculate, indistinctive or lobulated margin leading to misdiagnosing the lesions as malignant tumors.Full-field digital mammography (FFDM) is helpful in detection of breast cancers in women, with a higher sensitivity, specificity and accuracy, and has an important clinical application value.

To obtain the recombinant rv1837c and rv3803c of Mycobacterium tuberculosis using gene engineering technology and explore their prokaryotic expression, purification, and immunogenicity.The Mycobacterium tuberculosis rv1837c and rv3803c genes were amplified by polymerase chain reaction, and then cloned into the vector pTA2, followed by the subclone into the expression vector pET30a (+). The resulting plasmids, named pET30a (+): rv1837c and pET30a (+): rv3803c, encode recombinant protein containing a hexa-histidine tag on its N-terminus. pET30a (+): rv1837c and pET30a (+): rv3803c were introduced into E. coli BL21 (DE3) by transformation respectively, and the recombinant gene was induced with 0.4 mmol/L isopropyl-D-thiogalactopyranoside. The expressed products were identified by Western blot with hexa-histidine tag antibody and serum from tuberculotic patients. The histidine tagged protein was purified by nickel nitrilotriacetic acid His-Bind resin. Rabbits were immunized with purified recombinant Rv1837c and Rv3803c proteins. Then the purified recombinant Rv1837c and Rv3803c proteins were used to detect antibody in rabbit serum, which had been immunized by Western blot.After transformation of the E. coli and induction with 0.4 mmol/L of isopropyl-D-thiogalactopyranoside, recombinant target proteins Rv1837c (relative molecular mass: 92000) and Rv3803c (relative molecular mass: 38 000) were expressed in pET30a (+): rv1837c and pET30a (+): rv3803c system. The expressed protein existed in cytoplasm in an unsoluble form and amounted to 30% and 50% of the total proteins of E. coli. The purity of the purified protein reached 90%. The immunogenicity of the recombinant proteins Rv1837c and Rv3803c was strong, as identified by Western blot.The prokaryotic expression recombinant plasmids pET30a (+): rv1837c and pET30a (+): rv3803c was successfully constructed and the recombinant proteins Rv1837c and Rv3803c were obtained, which laid a basis for the optimized diagnosis of active tuberculosis.

Objective: To directly examine the effects of carnosine on neuronal excitation and inhibition in rat hippocampus in vivo. Methods: Artificial cerebrospinal fluid with carnosine was directly administrated over the exposed rat hippocampus. The changes of neuron activity in the CA1 region of hippocampus were evaluated by orthodromically- and antidromically-evoked potentials, as well as paired-pulse stimulation paradigm. Results: In both orthodromic and antidromic response potentials, carnosine transformed population spikes (PSs) with single spike into epileptiform multiple spikes. In addition, similar to the effect of γ-aminobutyric acidA (GABAA) antagonist picrotoxin, carnosine decreased paired-pulse stimulating depression significantly. However, no significant change was observed in the spontaneous field potentials during the application of carnosine. Conclusion: The results indicate a disinhibition-induced excitation effect of carnosine on the CA1 pyramidal neurons. It provides important information against the application of carnosine as a potential anticonvulsant in clinical treatment.

A new general nonlinear constitutive model is proposed for giant magnetostrictive materials. For the convenience of engineering applications, the expressions of the 3-D (bulk), 2-D (film) and 1-D (rod) models are respectively given for an isotropic material and their applicable regions are also identified. It is found that the new model can accurately predict the magnetostrictive strain curves in low, moderate and high magnetic field regions for various compressive pre-stress levels. The numerical simulation illustrates that, the new model, whether for magnetostrictive rods or for thin films, can effectively describe the effects of the pre-stress or residual stress on the magnetization and the magnetostrictive strain curves, which can not be captured by previous models.

The hippocampal region of the brain is important for encoding environment inputs and memory formation. However, the underlying mechanisms are unclear. To investigate the behavior of individual neurons in response to somatosensory inputs in the hippocampal CA1 region, we recorded and analyzed changes in local field potentials and the firing rates of individual pyramidal cells and interneurons during tail clamping in urethane-anesthetized rats. We also explored the mechanisms underlying the neuronal responses. Somatosensory stimulation, in the form of tail clamping, chan-ged local field potentials into theta rhythm-dominated waveforms, decreased the spike firing of pyramidal cells, and increased interneuron firing. In addition, somatosensory stimulation attenuated orthodromic-evoked population spikes. These results suggest that somatosensory stimulation suppresses the excitability of pyramidal cells in the hippocampal CA1 region. Increased inhibition by local interneurons might underlie this effect. These findings provide insight into the mechanisms of signal processing in the hippocampus and suggest that sensory stimulation might have therapeutic potential for brain disorders associated with neuronal hyperexcitability.

Piezoelectric devices present an important new group of sensors and actuators for active vibration control systems [1, 2, 3, 4]. Indeed, this technology allows to developing spatially distributed devices, which requires special control techniques to improve the dynamical behavior of this kind of smart structure. Especially to geometrically nonlinear plates with piezoelectric sensing and actuating, there is a little of numerical results in the literature to quantitatively analyze the behavior of the vibration control of the structures [5, 6, 7]. This paper is concerned with the mathematical model of this kind of vibration control for a geometrically nonlinear plate with piezoelectric sensors and actuators by means of the scaling function transform of the wavelet theory [8, 9]. Based on the generalized Gaussian integral to the scaling function transform, an explicit formula or algorithm of identification for the deflection of plates from the measured electric signals, i.e., electric charges and currents, on piezoelectric sensors is established. When a control law of negative feedback of the identified signals is employed, the applied voltages on piezoelectric actuators are determined by the wavelet Galerkin method. Finally, some typical examples, e.g., beam-plates with either small deflection or geometrically nonlinear deformation, of simulation are taken to show the feasibility of this control approach. It is found that this control model may auto-avoid those undesired phenomena of control instability generated from the interaction between measurement and controller with spilling over of high-order signals since the scaling function transform is low-pass.

A dynamic control model of suppressing external disturbance to beam-plates with piezoelectric sensors and actuators is developed by means of the scaling function transform of the Daubechies wavelet theory. By virtue of this new mathematical tool, an explicit formulation of identification of deflection configuration is expressed in terms of electric charge/current signals measured from piezoelectric sensors. After a control law of negative feedback of the identified deflection and velocity signals is employed, the wavelet Galerkin method or wavelet weighted residual method is used to determine a distribution of control voltage applied on the piezoelectric actuators. Due to that the scaling function transform is like a low-pass filter which can automatically filter out high- order signals of vibration or disturbance from the measurement and the controller employed here, this model does not lead to those undesired phenomena of control instability which is often appeared in a control system and caused by the spilling over of high-order signals from measurement and controller if no special technique is taken in the control system. Finally, a numerical simulation is carried out to show the efficiency and ability of the control program proposed in this paper. It is found that this control model is more efficient than a control program of convection to the example.

The magnetostrictive strain-applied field curve typical of giant magnetostrictive materials is nonlinear and it is affected notably by prestress and temperature. A constitutive model to describe these properties is suggested in this paper. The model considered here is built on the Gibbs free energy function G(σij,Mk,T). Thermodynamic relations are used to obtain the constitutive expressions. Results based on the model show that the nonlinear property of magnetostrictive strain, the magnetization, and Young’s modulus under different prestress and temperature are in excellent agreement with experimental data. Moreover, the proposed model is convenient to be used in engineering applications since the parameters referred to the model can all be easily determined by experiments.