Connect the Thermodynamics of Bulk and Confined Fluids: Confinement-Adsorption Scaling

A fluid (a gas or a liquid) adsorbed in a porous material can behave very differently from its bulk counterpart. The advent of various synthesized materials with nanopores and their wide applications have provided strong impetus for studying fluids in confinement because our current understanding is still incomplete. From a large number of Monte Carlo simulations, we found a scaling relation that allows for connecting some thermodynamic properties (chemical potential, free energy per particle, and grand potential per particle) of a confined fluid to the bulk ones. Upon rescaling the adsorbed fluid density, the adsorption isotherms for many different confining environments collapse to the corresponding bulk curve. We also reveal the intimate connection of the reported scaling relation to Gibbs theory of inhomogeneous fluids and morphological thermodynamics. The advance in our understanding of confined fluids, gained from this study, also opens attractive perspectives for circumventing experimental difficulty for directly measuring some fluid thermodynamic properties in nanoporous materials.

Fluids in porous media. IV. Quench effect on chemical potential

It appears to be a common sense to measure the crowdedness of a fluid system by the densities of the species constituting it. In the present work, we show that this ceases to be valid for confined fluids under some conditions. A quite thorough investigation is made for a hard sphere (HS) fluid adsorbed in a hard sphere matrix (a quench-annealed system) and its corresponding equilibrium binary mixture. When fluid particles are larger than matrix particles, the quench-annealed system can appear much more crowded than its corresponding equilibrium binary mixture, i.e., having a much higher fluid chemical potential, even when the density of each species is strictly the same in both systems, respectively. We believe that the insight gained from this study should be useful for the design of functionalized porous materials.

[Studies on the chemical constituents of Zanthoxylum dimorphophyllum Hemsl. var spinifolium Rhed. et Wils]

AIM

To study the chemical components from the dried roots of Zanthoxylum dimorphophyllum Hemsl. var spinifolium Rhed. et Wils.

METHODS

Modern chromatography was used to isolate chemical components and the compounds isolated from Zanthoxylum dimorphophyllum Hems1. var spinifolium Rhed. et Wils were identified by various spectral methods.

RESULTS

Five compounds were isolated and identified as 6-(2',3'-dihydroxy-3'-methybutyl)-7-acetoxy-2H-1-benzopyran-2-one (I), 6-(2',3'-dihydroxy-3'-methybutyl)-7-(beta-D-glucopyranosyloxy)- 2H-1-benzopyran-2-one (II), hexacosanoci acid (III), aurepten (IV), 6-[6'-O-(-deoxy-alpha-L-mannopyranosyl)-beta-D-benzopyran-4-one (V).

CONCLUSION

All of the above compounds were isolated from the plant for the first time, among them, I is a new compound.

[Structural elucidation of a new tetrahydroxystilbene of Radix Polygoni Multiflori Preparata and study on its cardiovascular activity]

AIM

To investigate the cardiovascular active constituents of Radix Polygoni multiflori Preparata.

METHODS

Compounds were isolated from the water soluble extract with column chromatography of Sephadex, ODS and HPLC. The compounds were identified on the basis of spectral analysis (IR, EI-MS, FAB-MS, 1HNMR, 13CNMR, 2D-NMR) and phytochemical properties. Its inhibitory effect on the proliferation of bovine vascular smooth muscle cells were bioassayed in vitro.

RESULTS

One compound was isolated and identified as: 2,3,5,4'-tetrahydroxystilbene-2-O-(6"-O-alpha-D- glucopyranosyl)-beta-D-glucopyranoside.

CONCLUSION

Compound I is a new compound with cardiovascular activity.

[A new fatty ketone of Radix Polygoni Multiflori Preparata]

OBJECTIVE

Investigating the chemical constituents of Radix Polygoni Multiflori Preparata.

METHODS

Compounds were isolated from the CHCl3 extract with column chromatography on silica gel, and identified on the basis of spectral analysis(IR, EI-MS, 1H-NMR, 13C-NMR) and phytochemical properties.

RESULTS

Two compounds were isolated and identified as 1,2-dihydroxynonadecone-3(I) and gallic acid(II).

CONCLUSION

Compound I is a new compound.

[Evaluation on antiendotoxic action and antiviral action in vitro of tetraploid Isatis indigotica]

OBJECTIVE

To evaluate the pharmacological effect of tetraploid Isatis indigotica Fort.

METHODS

Comparing these actions of tetraploid I. indigotica with those of the diploid parent.

RESULTS

These actions of tetraploid I. indigotica were obviously stronger than those of the diploid parent. The pharmacological effect of leaves was greater than that of roots with identical ploidy.

CONCLUSION

Tetraploid I. indigotica is a new line of better quality, deserving to be exploited and utilized on a large scale.

[Study of quality control on herbal drugs and preparations of daqingye and banlangen]

This paper first suggests that 2,4 (1H,3H) quinazolinedione (QZL) may be used as a quality control standard for the Chinese herbal drugs Daqingye (Folium Strobilanthis et Polygoni) and Banlangen (Radix Strobilanthis) as well as its preparations. QZL was found for the first time from the above mentioned two Chinese herbal drugs which has a representative property. Its content is stable. This made it possible to solve the difficulty of quality control for the preparations "antipyretic and common cold granules" and "Banlangan granules" and provide a reliable assay method to evaluate the quality of the herbal preparations. By changing the wavelength and using gradient elution in HPLC, 3 constituents can be determined through one injection by the present method, thus the time of determination may be shortened and the efficiency of assay increased. The method showed good linearity (r = 0.99998, n = 4) in the range of 0.2-3.2 micrograms/ml of QZL, the average recovery was above 95% with RSD < 1.5% (n = 3). HPLC condition: Column: LiChrosorb RP 18; elution gradient: methanol from 35% to 90% in water solution; determination wavelength: 226 nm and 288 nm.

[Studies on the source plants of semen Armeniacae Amerum and their distribution]

A Survey of the source plants of Semen Armeniacae Amarum and their distribution was made in 14 provinces of China. A new source plant of Semen Armeniacae Amarum, Armeniaca zhidanensis, was found and all the source plants of Semen Armeniacae Amarum were grouped in 7 distribution areas.

[Chemical studies of Strobilanthes cusia]

Seven compounds have been isolated from the whole plant of Strobilanthes cusia (Nees) O. Ktze. Three of them are triterpenes (I-III), two are indole alkaloids (IV, V), two are quinazolinone alkaloids (VI, VII). On the basis of spectral analysis and physicochemical properties, their structures were established as lupeol (I), betulin (II), lupenone (III), indigo (IV), indirubin (V), 4(3H)-quinazolinone (VI), 2,4(1H,3H)-quinazolinedione (VII). VI and VII were found from natural plant for the first time. The results of the pharmacological tests demonstrate that compound V has anticancer activity and compound VI has hypotensive action. Compound VII can be quantitatively determined by HPLC, which may serve as a quality control standard for materia medica and its preparations. Compounds VI and VII have been confirmed by means of synthesis.