Efficient promotion of methane hydrate formation and elimination of foam generation using fluorinated surfactants

Methane hydrate preparation is an effective method to store and transport methane.In promoters to facilitate methane hydrate formation,homogeneous surfactant solutions,sodium dodecyl sulfate(SDS)in particular,are more favorable than heterogeneous particles,thanks to their faster reaction rate,more storage capacity,and higher stability.Foaming,however,could not be avoided during hydrate dissociation with the presence of SDS.This paper investigated the ability of five fluorinated surfactants:potassium perfluorobutane sulfonate(PBS),potassium perfluorohexyl sulfonate(PHS),potassium perfluorooctane sulfonate(POS),ammonium perfluorooctane sulfonate(AOS),and tetraethylammonium perfluorooctyl sulfonate(TOS)to promote methane hydrate formation.It was found that both PBS and PHS achieve a storage capacity of 150(V/V,the volume of methane that can be stored by one volume of water)within 30 min,more than that of SDS.Cationic ions and the carbon chain length were then discussed on their effects during the formation.It was concluded that PBS,PHS,and POS produced no foam during hydrate dissociation,making them promising promoters in large-scale application.

Polymorphisms in PPARD,PPARG and APM1 associated with four types of Traditional Chinese Medicine constitutions

Based on the theory of constitution of Traditional Chinese Medicine （TCM）, the human population is divided into nine constitutions including one balanced constitution （Normality） and eight unbalanced constitutions （Yang-deficiency, Yin-deficiency, Phlegm-wetness, Qi-deficiency, Wetness-heat, Blood stasis, Depressed constitution, and Inherited special constitution）. Different constitutions have specific metabolic features and different susceptibility to certain diseases. However, whether a genetic basis accounts for such constitution classification is yet to be determined. Here we performed a genetic study to assess the association between genetic variations of metabolic genes including PPARD, PPARG and APM1 and the constitutions. A total of 233 individuals of the Han population in China were classified into four groups, Normality, Yang-deficiency, Yin-deficiency and Phlegm-wetness with whom 23 single nucleotide polymorphisms （SNPs） in the three genes were genotyped using polymerase chain reaction-restriction fragment length polymorphism （PCR-RFLP） method. Biased distribution of PPARD rs2267669 and rs2076167, APM1 rs7627128 and rs1063539 in Yang-deficiency, PPARG Prol2Ala in Yin-deficiency and PPARD rs2076167, APMI rs266729 and rs7627128 in Phlegm-wetness were observed. The frequencies of Haplotypel3 （Hapl3） of PPARG in Yin-deficiency, Hap25 of APM1 in Yang-deficiency and Hap2 of PPARD and Hapl4 of PPARG in Phlegm-wetness, were significantly different from those in Normality, suggesting those might be group-associated haplotypes. These results suggested that single SNP and haplotypes ofPPARD, PPARG and APM1 may underlie the genetic basis of the constitutions classified in TCM.