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The purpose of this paper is to show that a biped robot can walk by an imitation control. It proposes architecture and system for real-time imitation control of a biped robot. Using this method, the operator can interact with the robot to walk. The operator produces trajectory data necessary to start, stop, walk and redirect the robot. We have to send control commands or new angular position values for to the robot as fast as possible. To get intuition how fast the robot should be controlled, its falling time which as the primary time question is discussed. An inverted pendulum calculation example and the real robot fall down experiment were compared in this paper.

To realizing the imitation control of the biped humanoid robot, synchronous question is the core problem. Falling time of the robot and reflecting time of the operator both are the components which to real-time control of the robot. If the robot can walk well in limited time, between the two parts time questions, communication time need us to analyze. Based on the imitation control structure of our robot control system, characters of control model and communication system were studied and conclusions show that synchronous control for a robot by a human is difficult to realize and some other stable control methods need to add in the research.

AIM: To investigate the effect of natriuretic peptides on gastric motility in various animals, and the effect of C-type natriuretic peptide (CNP) on spontaneous contraction of gastric smooth muscle in rat, guinea-pig and human in vitro was compared. METHODS: Spontaneous contraction of gastric smooth muscle was recorded by four channel physiograph. RESULTS: In the guinea-pig and rat gastric antral circular smooth muscle, CNP markedly decreased the amplitude of spontaneous contraction but it didn’t affect the frequency, however, the contractile activity was completely inhibited by CNP in gastric antral longitudinal smooth muscle. In the human gastric antral circular and longitudinal smooth musle, CNP completely inhibited spontaneous contraction. In the circular smooth muscle of guinea-pig and rat gastric fundus, CNP obviously decreased the amplitude of spontaneous contraction but it didn’t affect the frequency, however, the contractile activity was completely inhibited by CNP in smooth muscle of fundus longitudinal. In the circular and longitudinal smooth muscle of guinea-pig gastric body, CNP at first induced a relaxation and then an increase in amplitude of spontaneous contraction (rebound contraction), but the frequency was not changed. After the circular smooth muscle of gastric body was pretreated with atropine, an M receptor blocker, the rebound contraction was abolished; In circular and longitudinal smooth muscle of rat gastric body, CNP induced a transient and slight relaxation and successively followed by the recovery in amplitude of spontaneous contraction but it also didn’t affect the frequency. After the smooth muscle was pretreated with atropine, the transient and slight relaxation was replaced by long term and complete inhibition; The percentage of CNP-induced inhibition was 76.77% ± 6.21% (fundus), 67.21% ± 5.32% (body) and 58.23% ± 6.21% (antral) in the gastric circular muscle, however, the inhibitory percentage was 100% ± 0.00% (fundus), 68.66% ± 3.55% (body) and 100% ± 0.00% (antrum) in the gastric longitudinal smooth muscle of guinea-pigs; In the rat, the percentage of CNP-induced inhibition was 95.87% ± 4.12% (fundus), 94.91% ± 5.08% (body) and 66.32% ± 7.32% (antrum) in the gastric circular smooth muscle, but in the longitudinal smooth muscle, CNP completely inhibited the spontaneous contraction. Using LY83583, a guanylate cyclase inhibitor, and zaparinast as a phosphoesterase inhibitor to inhibit the generation of cGMP, the effect of CNP on the spontaneous contraction was markedly weakened by LY83583, however, the inhibitory effect was enhanced by zaparinast. CONCLUSION: (1) CNP can obviously inhibit the spontaneous contraction of gastric antral circular and longitudinal smooth muscle in the rat, guinea-pig and human. The order of inhibitory potency is human > rat > guinea-pig. (2) In the same animals, the inhibitory effect of CNP on spontaneous contraction is the most powerful in fundus and the weakest in antrum, in the same position, the inhibitory effect on the circular smooth muscle is more powerful than that on longitudinal smooth muscle. (3) The inhibitory effect of CNP on spontaneous contraction in the gastric smooth muscle is mediated by a cGMP dependent pathway.

To investigate the effect of ectogenesis unsaturated fatty acid on carbachol-induced muscarinic current (ICCh) and its mechanism.Using the whole-cell patch-clamp technique, ICCh was recorded in single smooth muscle cell isolated from the antral circular smooth muscles of guinea-pig stomach.Arachidonic acid (AA) was added in external perfusing solution and AA inhibited ICCh to 46 %+/-8 %, 23 %+/-5 %, and 3.8 %+/-0.9 % at 1, 3, and 5 micromol/L. Another unsaturated fatty acid, linoleic acid (LA) also inhibited ICCh in a dose-dependant manner. LA inhibited ICCh to 69 %+/-10 %, 35 %+/-5 %, and 7.4 %+/-1.2 % at 1, 5, and 10 micromol/L, respectively. The same concentration (5 micromol/L) of AA, LA, and oleic acid (OA) suppressed ICCh to 3.8 %+/-0.9 %, 35 %+/-5 %, and 67 %+/-9 %, respectively. The inhibitory potency sequence of these unsaturated fatty acids was AALAOA. After 10-15 min of pretreatment with H-7 (a protein phosphorylation C inhibitor) 100 micromol/L or indomethacin (a cyclooxygenase inhibitor) 10 micromol/L, ICCh was inhibited by 5 micromol/L of AA to 5.5 %+/-0.7 % and 3.0 %+/-1.0 %, respectively.The unsaturated fatty acids directly inhibited ICCh, and the inhibitory potency was related to the number of double bonds in fatty acid chain.

To investigate the function of exogenous unsaturated fatty acids in hyposmotic membrane stretch enhancement of muscarinic current (ICCh) in antral circular smooth muscle cells of guinea pig, we recorded the membrane current with the conventional whole cell patch-clamp technique. I(CCh) elicited by 50 micromol/L carbachol (CCh) at the holding potential of 20 mV under isosmotic condition was taken as control. Hyposmotic membrane stretch increased I(CCh) to 226.0+/-21.0%. When the cells were pretreated with 5 micromol/L arachidonic acid (AA), linoleic acid (LA) or oleic acid (OA), I(CCh)was inhibited to 3.8+/-0.6%, 35.2+/-0.8% and 66.6+/-0.6% respectively. Hyposmotic membrane stretch increased I(CCh) to 106.0+/-2.5%, 173.2+/-6.8% and 222.1+/-11.0% of the control respectively. Five micromol/L AA inhibited hyposmotic membrane stretch-enhanced I(CCh) by 51.2+/-3.8%, while the control I(CCh) under isosmotic condition was inhibited by 96.2+/-1.6%. The results suggest that unsaturated fatty acids inhibited I(CCh) and the inhibitory effect is more significant when the unsaturation degree is increased. However, the unsaturated fatty acids are not involved in the increase of I(CCh) induced by hyposmotic membrane stretch.

To investigate ion channel mechanism in CNP-induced relaxation of gastric circular smooth muscle in guinea pigs.Spontaneous contraction of gastric smooth muscle was recorded by a four -channel physiograph. The whole cell patch-clamp technique was used to record calcium-activated potassium currents and membrane potential in the gastric myocytes isolated by collagenase.C-type natriuretic peptide (CNP) markedly inhibited the spontaneous contraction in a dose-dependent manner in gastric circular smooth muscle in guinea pigs. Ly83583, an inhibitor of guanylate cyclase, weakened CNP-induced inhibition on spontaneous contraction but Zaparinast, an inhibitor of cGMP sensitive phosphoesterase, potentiated CNP-induced inhibition in gastric circular smooth muscles. The inhibitory effects of CNP on spontaneous contraction were blocked by tetrathylammonium (TEA), a nonselective potassium channel blocker. CNP hyperpolarized membrane potential from -60.0 mV+/-2.0 mV to -68.3 mV+/-3.0 mV in a single gastric myocyte. CNP increased calcium-activated potassium currents (I(K(ca))) in a dose-dependent manner in gastric circular myocytes. CNP also increased the spontaneously transient outward currents (STOCs). Ly83583 partly blocked CNP-induced increase of calcium-activated potassium currents, but Zaparinast potented the effect.CNP inhibits spontaneous contraction, and potassium channel may be involved in the process in gastric circular smooth muscle of guinea pigs. CNP-induced increase of I(K(ca)) is mediated by a cGMP dependent pathway.