No abstract

In order to investigate the effects of supplemental ionic surfactants in in vitro ruminal fermentation, N-Lauroylsarcosine sodium salt (N-LSS) and sodium dodecyl sulfate (SDS) for negative ( ) ionic surfactant, and hexadecylpyridinium chloride monohydrate (HPCM) and hexadecyltrimethyl ammonium bromide (HTAB) for positive (+) ionic surfactant were supplemented by 0.05% and 0.1% into the Dehority's artificial medium containing rice straw (1 mm) as a substrate. In vitro DM digestibility, the growth of rumen mixed microbes, pH, cumulative gas production and SEM (Scanning Electron Microscopy) observation of microbial attachment on rice straw particle were investigated through the experiment composing 9 treatments (two supplemental levels of two positive ionic (+) surfactant, two supplemental levels of two negative ( ) ionic surfactant) including the control. The sample collection was at 6, 12, 24, 48 and 72 h post fermentation with 3 replications per treatments. DM digestibility in treatments supplemented (+) or ( ) surfactants almost stopped afterward 12 h fermentation, in vitro DM digestibility at 72 h post fermentation in the ionic surfactants was at half level of that of the control (P<0.05). Accumulative gas production in in vitro was less (P<0.05) with addition of ionic surfactants compared to the control. The amount of rumen mixed microbes recovered from in vitro incubation fluid pleateaued at 12 h post fermentation for the positive (+) ionic surfactants, but steadily increased as fermentation time elapsed for the control. Rumen microbial growth rate was significantly (P<0.05) low in the negative ( ) ionic surfactant compared to the control. pH of the incubation fluid was ranged from 6.02 to 7.20, and was the highest in the negative ( ) ionic surfactants, and was the lowest in the control (P<0.05). In SEM observation, rumen microbial population attached on rice straw particle was less with addition of ionic surfactants than the control. In conclusion we could not found any positive effects of negative-and positive-charged surfactants on rumunal fermentation characteristics and rumen microbial growth rates.

No abstract

The purpose of this study was to compare kinematic variables and stiffnesses of ankle joints between normal person and transfemoral amputee gait in order to develop or fit prosthetic leg. Twenty subjects (ten normal persons and ten transfemoral amputees) participated in this experiment, and walked three trials at a self-selected pace. The gait motions were captured with Vicon system and variables were calculated with Visual-3D. The velocity, stride length, stride width, cycle time, double limb support time and right swing time of gaits were statistically significant. Because coefficients of variability of normal persons on velocity, double limb support time and swing time were greater than transfemoral amputees, normal persons controlled these gait variables effectively. The stiffnesses of ankle joints were not statistically significant, but patterns of stiffnesses of ankle joints during three rockers were absolutely different. The negative correlations between stiffnesses of ankle joints and cycle time and swing time were presented. These differences suggest that developing and fitting prosthetic leg were demanded. Further studies should develop fitting program and simulator of prosthetic leg.