One step isolation and purification of liquiritigenin and isoliquiritigenin from Glycyrrhiza uralensis Risch using high-speed counter-current chromatography

High-speed counter-current chromatography (HSCCC) technique in semi-preparative scale has been successfully applied to the separation of bioactive flavonoid compounds, liquiritigenin and isoliquiritigenin in one step from the crude extract of Glycyrrhiza uralensis Risch. The HSCCC was performed using a two-phase solvent system composed of n-hexane-ethyl acetate-methanol-acetonitrile-water (2:2:1:0.6:2, v/v). Yields of liquiritigenin (98.9% purity) and isoliquiritigenin (98.3% purity) obtained were 0.52% and 0.32%. Chemical structures of the purified liquiritigenin and isoliquiritigenin were identified by electrospray ionization-MS (ESI-MS) and NMR analysis. (c) 2005 Published by Elsevier B.V.

Separation of neutral compounds by high speed capillary electrochromatography

With using short capillary column packed with porous and non-porous ODS stationary phases, high speed separation of 6 neutral aromatic compounds within 36 s by capillary electrochromatography (CEC) has been performed. Good reproducibility of the migration times for those solutes in high speed CEC was observed with RSD less than 1%. Both the linear velocity of EOF and the current linearly increases with the applied voltage, which means that the thermal effect by Joule heating was small. However, the capacity factor of solutes was found to decrease with the increase of the applied voltage, which was caused by the fact that about several seconds needed for the increase of voltage from 0 to applied value on a commercial CE instrument made larger contributions to the migration times of the early eluted compounds than those of lately eluted ones during high speed CEC, and voltage effect would increase with the higher applied voltage used. The linear relationship between the logarithm of capacity factor and the number of carbon for homologous compounds was observed, and positive value of slope means that the hydrophobicity of solutes is one of the main contribution factors to retention in high speed CEC packed with ODS stationary phases.

投射性空间关系表达过程的研究

It is easy to find that, in each language, the terms and phrases for the representation of spatial locating and orientation, and the ways for sharing spatial knowledge are very rich. The basic way of sharing spatial information is mapping our experience and actions with the environment by using terms and utterances that represent spatial relations. How to build the mapping relation among them and what factors affect the process of mapping are the questions need to be answered in this study. The whole course of expressing projective spatial relation includes the verbal expression and perception to the projective spatial relation. In experiment 1, the perceptual characteristics of perceiving the projective spatial relation was studied by analyzing the production latencies from the presentation of the stimulators in different directions (at 5 levels: 00, 22.50, 450, 67.50, and 900) to the onset of the corresponding buttons triggering on the keyboard, the study verifies the results of prior researches and revealed the foundation of expressing the projective spatial relation. In the experiment 2, and 3, the way and the role of the verbal expression were investigated. Subjects were asked to speak out the spatial relation between intended object and reference object by using verbal locative expressions. In experiment 2, Chinese was used as the verbal expression way, and in Experiment 3, English instead. Experiment 4 was similar as experiment 3, but time of voice key triggering was controlled and balanced among trials to verify the results of Experiment 3 further. Experiment 5 investigated the effect of pre-cue on the courses of expressing projective spatial relation. There were two kinds of clues, one was the spatial locative utterances, and the other was the perceptual coordinates framework, such as drawing a cross ”+” in a circle to imply four quadrants. The main conclusions of this research were as follows: 1. When speaking out a spatial relation, different sets of spatial terms, such as “left and right”, or “north and south”, affected the speed of verbal expression. Verbal coding process was affected by how well the perceptual salient direction matched with spatial terms, which made the speed of verbal expression different. 2. When using composite spatial terms to express diagonal directions, people tend to use direct mapping from spatial conceptual representation to composite spatial terms, rather than combining the two axes, which implied there existed direct one-on-one mapping between spatial conceptual representation and spatial terms. But during specific developing period, the way of combining two axes was employed as well for spatial expression, which meant perceptual salient directions played critical role in the process of perceiving and expressing projective spatial relations. 3. The process of verbal expression of the projective spatial relation was improved by the familiarity of spatial utterances, but this improvement was not the results of enhancement of the effect of prototypical diagonal direction.

心理旋转中的整体优先效应及其机制

In the history of psychology research, more attention had been focused on the relation between local processing and global processing. For the global information and the local information, which is processed earlier? And which is processed faster? Precedence of the global over the local level in visual perception has been well established by Navon with compound stimuli, and Navon’s original study gave rise to many publications, including replications, generalization to other kinds of stimuli (nonverbal material, digits), populations (infants, children, brain-damaged subjects), and tasks (lateral visual hemifield presentation, copy drawing, memory recognition, and recall), and triggered some debate about the conditions in which global precedence is and is not observed (number, size, sparsity, and goodness of the stimuli, exposure duration, etc.). However, whether there is a global advantage or precedence in other cognitive processes was less tested. Most researches had suggested that there was a functional equivalency between visual perception and visual image processing. However, it’s still unknown whether there will be a global advantage on mental rotation. In the present study, we combined the mental rotation task with the compound stimuli to explore whether the global or local advantage also existed at the mental imagery transformation stages. In two pilot studies, the perceptual global precedence was found to be present in a normal/mirror-image judgment task when the stimuli exposure time was short; while the stimuli exposure time was prolonged (stimuli kept available till subjects’ response) the perceptual global precedence was showed to be eliminated. In all of the subsequent experiments, stimili would be presented till subjects’ response. Then mental rotation was added in normal/mirror-image judgment (some of the stimuli were rotated to certain angles from upright) in normal experiments, experiment 1 and 2 observed a global advantage on mental rotation both with a focused-attention design (Experiment 1) and divided-attention design (Experiment 2). Subjects’ reaction times were increased with rotation angles, and the accuracy was decreased with rotation angles, suggesting that subject need a mental rotation to make a normal/mirror judgment. The most important results were that subjects’ response to global rotation was faster than that to local rotation. The analysis of slope of rotation further indicated that, to some extend, the speed of global rotation was faster than that of local rotation. These results suggest a global advantage on mental rotation. Experiment 3 took advantage of the high temporal resolution of event-related potentials to explore the temporal pattern of global advantage on mental rotation. Event-related potential results indicated the parietal P300 amplitude was inversely related to the character orientation, and the local rotation task delayed the onset of the mental-rotation-related negativity at parietal electrodes. None clear effect was found for occipital N150. All these results suggested that the global rotation was not only processed faster than local rotation, but also occurred earlier than local rotation. Experiments 4 and 5 took the effect size of global advantage as the main dependent variable, and visual angle and exposure duration of the stimuli as independent variables, to examine the relationship between perceptual global precedence and global advantage on mental rotation. Results indicated that visual angle and exposure duration did not influence the effect size of global advantage on mental rotation. The global advantage on mental rotation and the perceptual global advantage seemed to be independent but their effects could be accumulated at some condition. These findings not only contribute to revealing a new processing property of mental rotation, but also deepen our understanding of the problem of global/local processing and shed light on the debate on locus of global precedence.

汉字早期字形加工

The researches of the CC's form processing mainly involved the effects of all kinds of form properties. In most of the cases, the researches were conducted after the lexical process completed. A few which was about early phases of visual perception focused on the process of feature extraction in character recognition. Up till now, nobody put forward a propose that we should study the form processing in the early phases of visual perception of CC. We hold that because the form processing occurs in the early phases of visual perception, we should study the processing prelexically. Moreover, visual perception of CC is a course during which the CC becomes clear gradually, so that the effects of all kinds of form properties should not be a absolute phenomena of an all-or-none. In this study we adopted 4 methods to research the form processing in the early phases simulatedly and systematically, including the tachistoscopic repetition, increasing time to present gradually, enlarging the visual angle gradually and non- tachistoscopic searching and naming. Under all kinds of bad or degraded visual conditions, the instantaneous course of early-phases processing was slowed down and postponed, and then the growth course was open to before our eyes. We can captured the characteristics of the form processing in the early phases by analyzing the reaction speed and recognition accuracy. Accompanying the visual angle and time increasing, the clarity improved and we can find out the relation between the effects of form properties and visual clarity improving. The results were as follows: ①in the early phases of visual perception of CC, there were the effects of all kinds of form properties. ②the quantity of the effects would cut down when the visual conditions were being changed better and better. We raised the concept of character's space transparency and it's algorithm to explain these effects of form properties. Furthermore, a model was discussed to help understand the phenomenon that the quantity of the effects changed as the visual conditions were improved. ③The early phases of visual perception of CC isn't the loci of the frequency effect.

Large-pore mesoporous SBA-15 silica particles with submicrometer size as stationary phases for high-speed CEC separation

A new mesoporous sphere-like SBA-15 silica was synthesized and evaluated in terms of its suitability as stationary phases for CEC. The unique and attractive properties of the silica particle are its submicrometer particle size of 400 nm and highly ordered cylindrical mesopores with uniform pore size of 12 nm running along the same direction. The bare silica particles with submicrometer size have been successfully employed for the normal-phase electrochromatographic separation of polar compounds with high efficiency (e.g., 210 000 for thiourea), which is matched well with its submicrometer particle size. The Van Deemeter plot showed the hindrance to mass transfer because of the existence of pore structure. The lowest plate height of 2.0 mu m was obtained at the linear velocity of 1.1 mm/s. On the other hand, because of the relatively high linear velocity (e.g., 4.0 mm/s) can be generated, high-speed separation of neutral compounds, anilines, and basic pharmaceuticals in CEC with C-18-modified SBA-15 silica as stationary phases was achieved within 36, 60, and 34 s, respectively.