Changes in muscle recruitment patterns during skill acquisition

The control of movement is predicated upon a system of constraints of musculoskeletal and neural origin. The focus of the present study was upon the manner in which such constraints are adapted or superseded during the acquisition of motor skill. Individuals participated in five experimental sessions, ill which they attempted to produce abduction-adduction movements of the index finger in time with an auditory metronome. During each trial, the metronome frequency was increased in eight steps from an individually determined base frequency. Electromyographic (EMC) activity was recorded from first dorsal interosseous (FDI), first volar interosseous (FVI), flexor digitorum superficialis (FDS), and extensor digitorum communis (EDC) muscles. The movements produced on the final day of acquisition more accurately matched the required profile, and exhibited greater spatial and temporal stability, than those generated during initial performance. Tn the early stages of skill acquisition, an alternating pattern of activation in FDI and FVI was maintained, even at the highest frequencies. Tn contrast, as the frequency of movement was increased, activity in FDS and EDC was either tonic or intermittent. As learning proceeded, alterations in recruitment patterns were expressed primarily in the extrinsic muscles (EDC and FDS). These changes took the form of increases in the postural role of these muscles, shifts to phasic patterns of activation, or selective disengagement of these muscles. These findings suggest that there is considerable flexibility in the composition of muscle synergies, which is exploited by individuals during the acquisition of coordination.

Development of an immunobiosensor assay for the beta-adrenergic compound zilpaterol

A surface plasmon resonance biosensor method was developed to measure zilpaterol residues in sheep urine. A CM-5 sensor chip previously reacted with ethylenediamine to produce an aminoethyl group was coupled with 4-carboxybutyl zilpaterol activated using EDC/NHS. Five polyclonal and four monoclonal antibodies were screened for their suitability to detect low levels of zilpaterol using the biosensor technology. Total binding was greater for polyclonal than monoclonal antibodies, but a less diluted antibody solution was required for polyclonal antibodies. A fixed antibody concentration and various concentrations of zilpaterol were injected to obtain a standard curve for each antibody to allow for B-0 and IC50 determination. The stability of the assay was assessed by the consistency of B0 in repeated experiments extending at least six hours. A measure of non-specific binding allowed the assessment of the specificity of the antibody-immobilized ligand interaction. The effect of varying concentrations of urine on B-0 and IC50 was evaluated to assess the degree of

Preparation of Highly Stable OEG derivatives-functionalized AuNPs and Its Application in LSPR-based Detection of PSA/ACT Complex

The zero-length crosslinker EDC has been widely used to make amide bonds between carboxylic acid and amine groups for bioconjugation because no residues remain in the crosslinked protein. During the conjugation process, EDC activates the carboxyl groups (negatively charged) and forms an unstable amine-reactive intermediate (positively charged). However, the process turns to be a problematic issue if it is applied to modify carboxyl-functionalized and –stabilized Au nanoparticles (AuNPs) due to the fact that the negatively repulsive forces which help to stabilize the AuNPs were disrupted leading to the colloid aggregation. Therefore, to modify the negatively carboxyl-terminated AuNPs while their stability can be maintained yet, we assume that functionalization of the AuNPs using 02 kinds of negatively charged groups which one serves as a linking agent, and the other one plays a role of negative charge maintainer could overcome the impediment.

In this study, the colloidal gold nanoparticles were synthesized by Turkevitch’s method, and then their surface was rationally functionalized with different molar ratios of HS(CH2)11(OCH2CH2)6OCH2COOH and HS(CH2)11(OCH2CH2)3OH (OEG6-COOH/OEG3-OH) by self assembling technique. As a result, the most appropriate molar ratio was found to be 1:10, and the AuNP aggregation was prevented not only in the activation process by EDC but also in the present of high concentration of NaCl as well as over in a wide pH range. This is the first time that extremely stable OEG derivatives-functionalized Au nanoparticles for protein bioconjugation using EDC chemistry is reported, and the results open the door for covalent bioconjugation of AuNPs in biological applications.

Modeling of Turbulent Natural Gas and Biogas Flames of the Delft Jet-in-Hot-Coflow Burner: Effects of Coflow Temperature, Fuel Temperature and Fuel Composition on the Flame Lift-Off Height

The structure of a turbulent non-premixed flame of a biogas fuel in a hot and diluted coflow mimicking moderate and intense low dilution (MILD) combustion is studied numerically. Biogas fuel is obtained by dilution of Dutch natural gas (DNG) with CO2. The results of biogas combustion are compared with those of DNG combustion in the Delft Jet-in-Hot-Coflow (DJHC) burner. New experimental measurements of lift-off height and of velocity and temperature statistics have been made to provide a database for evaluating the capability of numerical methods in predicting the flame structure. Compared to the lift-off height of the DNG flame, addition of 30 % carbon dioxide to the fuel increases the lift-off height by less than 15 %. Numerical simulations are conducted by solving the RANS equations using Reynolds stress model (RSM) as turbulence model in combination with EDC (Eddy Dissipation Concept) and transported probability density function (PDF) as turbulence-chemistry interaction models. The DRM19 reduced mechanism is used as chemical kinetics with the EDC model. A tabulated chemistry model based on the Flamelet Generated Manifold (FGM) is adopted in the PDF method. The table describes a non-adiabatic three stream mixing problem between fuel, coflow and ambient air based on igniting counterflow diffusion flamelets. The results show that the EDC/DRM19 and PDF/FGM models predict the experimentally observed decreasing trend of lift-off height with increase of the coflow temperature. Although more detailed chemistry is used with EDC, the temperature fluctuations at the coflow inlet (approximately 100K) cannot be included resulting in a significant overprediction of the flame temperature. Only the PDF modeling results with temperature fluctuations predict the correct mean temperature profiles of the biogas case and compare well with the experimental temperature distributions.