Adsorption equilibrium of citric acid from supercritical carbon dioxide/ethanol on cyano column

Supercritical adsorption equilibrium has a significant role in defining supercritical adsorption behavior. In this paper, the adsorption equilibrium of citric acid from supercritical CO2/ethanol on a cyano column was systematically investigated with the elution by characteristic point method. Equilibrium loading was obtained at 313.15 K and 321.15 K with supercritical CO2/ethanol densities varying from 0.7068 g·cm-3to 0.8019 g·cm-3. The experimental results showed that the adsorption capacity of citric acid decreased with increasing temperature and increasing density of the supercritical CO2/ethanol mobile phase. The adsorption equilibrium data were fitted well by the Quadratic Hill isotherm model and the isotherms showed anti-Langmuir behavior. The monolayer saturation adsorption capacity of citric acid is in the range of 44.54 mg·cm-3to 64.66 mg·cm-3with an average value of 56.86 mg·cm-3.

Behavioral animal models of depression

Depression is a chronic,recurring and potentially life-threatening illness that affects up to 20%of the population across the world.Despite its prevalence and considerable impact on human,little is known about its pathogenesis.One of the major reasons is the restricted availability of validated animal models due to the absence of consensus on the pathology and etiology of depression.Besides,some core symptoms such as depressed mood,feeling of worthlessness,and recurring thoughts of death or suicide,are impossible to be modeled on laboratory animals.Currently,the criteria for identifying animal models of depression rely on either of the 2 principles：actions of known antidepressants and responses to stress.This review mainly focuses on the most widely used animal models of depression,including learned helplessness,chronic mild stress,and social defeat paradigms.Also,the behavioral tests for screening antidepressants,such as forced swimming test and tail suspension test,are also discussed.The advantages and major drawbacks of each model are evaluated.In prospective,new techniques that will be beneficial for developing novel animal models or detecting depression are discussed.

Soil Respiration Dynamics and Influencing Factors in Typical Steppe of Inner Mongolia under Long-term Nitrogen Addition

We investigated soil respiration(Rs)dynamics and influencing factors under different nitrogen(N)addition levels(0,2,4,8,16,32 g m^–2 yr^–1)on typical grassland plots in Inner Mongolia.We measured soil respiration,temperature,moisture and nutrients.We found that N addition did not change dynamic characteristics of Rs;daily and seasonal dynamics followed a single peak curve.N addition reduced Rs during the growing season.Rs under N2,N4,N8,N16 and N32 treatments decreased by 24.00%,21.93%,23.49%,30.78%and 28.20%in the growing season,respectively,compared to the N0 treatment.However,Rs in the non-growing season was not different across treatments.Rs was significantly positively correlated with soil temperature and moisture and these two factors accounted for 72%–97% and 74%–82% of variation in Rs,respectively.The soil respiration temperature sensitivity (Q10) was between 2.27 and 4.16 and N addition reduced Q10 except in the N8 treatment.