Inhibitory effect of Tong Xie-Yao Fang formula on colonic contraction in rats

AIM:To investigate the pharmacological effect ofTong Xie-Yao Fang(TXYF)formula and its underlying mechanisms.METHODS:A neonatal maternal separation plus restraint stress(NMS+RS)model of diarrheapredominant irritable bowel syndrome was developed by subjecting male Sprague-Dawley rats to daily maternal separation from postnatal days 2 to 21 plus restraint stress from days 50 to 59.Rats were randomly divided into two groups(NMS+RS and TXYF formula),and rats with no handling or separation were used as normal controls.Starting from postnatal day 60,rats were administered TXYF formula(9.84 g/100 g body weight)orally twice daily for 14 consecutive days,while the normal and NMS+RS groups were given distilled water.The distinctions of movement index(MI,area under the curve of contraction intensity/min,mg/min)and contraction frequency(CF,number of contractions/min,times/min)of isolated colonic longitudinal smooth muscle strips(CLSMs)in the three groups before and after treatment were observed with a Power Lab system.Different inhibitors were applied,and then 10-4mol/L acetylcholine chloride(Ach)was added to CLSMs to induce muscle contraction.RESULTS:Before treatment,the MI of CLSMs in the NMS+RS and TXYF formula groups was similar and both higher than that in the normal group(545.49±73.66 mg/min vs 245.76±34.44 mg/min and551.09±54.29 mg/min vs 245.76±34.44 mg/min,P<0.01,respectively).After treatment,the MI in the TXYF formula group was lower than that in the NMS+RS group(261.39±38.59 mg/min vs 533.9±61.63 mg/min,P<0.01).In the same way,the CF of CLSMs in the NMS+RS and TXYF formula groups was similar and both higher than that in the normal group(3.42±0.25 times/min and 3.31±0.21 vs1.1±0.17 times/min,P<0.01)before treatment.After treatment,the CF in the TXYF formula group was lower than that in the NMS+RS group(1.42±0.87 times/min vs 3.11±0.82 times/min,P<0.01)and similar to that in the normal group(1.42±0.87 times/min vs 1.09±0.13 times/min).When8-(N,N-diethylamino)octyl 3,4,5-trimethoxybenzoate hydrochloride and 4-aminopyridine were added to the bath and equilibrated for 30 min,respectively,and10-4 mol/L Ach was added to CLSMs to induce muscle contraction,MI of the CLSMs in the TXYF formula group was lower than that in the normal group(666±36.32 mg/min vs 747.77±49.47 mg/min,and 686.53±39.17 mg/min vs 750.45±29.39 mg/min;P<0.01,respectively).The MI of CLSMs in the TXYF formula group was lower than that in the normal group after treatment with nifedipine(689.48±30.84 mg/min vs741.65±32.41 mg/min;P<0.05).CONCLUSION:TXYF formula inhibits colon contraction in rats.This may be related to activation of specific potassium channels and inhibition of extracellular calcium internal flow.

Computational fluid dynamics applied to high temperature hydrogen separation membranes

This work reviews the development of computational fluid dynamics （CFD） modeling for hydrogen separation, with a focus on high temperature membranes to address industrial requirements in terms of membrane systems as contactors, or in membrane reactor arrange- ments. CFD modeling of membrane,.s attracts interesting challenges as the membrane provides a discontinuity of flow, and therefore cannot be solved by the Navier-Stokes equations. To address this problem, tile concept of source has been introduced to understand gas flows on both sides or domains （feed and permeate） of the membrane. This is an important solution, as the gas flow and concentrations in the permeate domain are intrinsically affected by the gas flow and concentrations in the feed domain and vice-versa. In turn, the source term will depend on the membrane used, as different membrane materials comply with different transport mechanisms, in addition to varying gas selectiv- ity and fluxes. This work also addresses concentration polarization, a common effect in membrane systems, though its significance is dependent upon the performance of the membrane coupled with the operating conditions. Finally, CFD modeling is shifting from simplified single gas simulation to industrial gas mixtures, when the mathematical treatment becomes more complex.