Development of neural basis for chinese orthographic neighborhood size effect.

The brain activity of orthographic neighborhood size (N size) effect in Chinese character naming has been studied in adults, meanwhile behavioral studies have revealed a developmental trend of Chinese N-size effect in developing readers. However, it is unclear whether and how the neural mechanism of N-size effect changes in Chinese children along with development. Here we address this issue using functional magnetic resonance imaging. Forty-four students from the 3(rd) , 5(th) , and 7(th) grades were scanned during silent naming of Chinese characters. After scanning, all participants took part in an overt naming test outside the scanner, and results of the naming task showed that the 3(rd) graders named characters from large neighborhoods faster than those from small neighborhoods, revealing a facilitatory N-size effect; the 5(th) graders showed null N-size effect while the 7(th) graders showed an inhibitory N-size effect. Neuroimaging results revealed that only the 3(rd) graders exhibited a significant N-size effect in the left middle occipital activity, with greater activation for large N-size characters. Results of 5(th) and 7(th) graders showed significant N-size effects in the left middle frontal gyrus, in which 5(th) graders induced greater activation in large N-size condition than in small N-size condition, while 7(th) graders exhibited an opposite effect which was similar to the adult pattern reported in a previous study. The current findings suggested the transition from broadly tuned to finely tuned orthographic representation with reading development, and the inhibition from neighbors' phonology for higher graders. Hum Brain Mapp 37:632-647, 2016. © 2015 Wiley Periodicals, Inc.

Preparation of chitosan-modified silica nanoparticles and their applications in the separation of auxins by capillary electrophoresis.

In recent years, nanoparticles have gained more attention when used in separation science. In this study, chitosan-modified silica nanoparticles were successfully synthesized and characterized by transmission electron microscopy, elemental analysis and zeta potential measurements, etc. When added into the running buffer solution as pseudo-stationary phase in capillary electrophoresis, the separation of four representative auxins, i.e., indole-3-acetic acid, indole butyric acid, 2,4-dichlorophenoxyacetic acid, 1-naphthaleneacetic acid, was carried out. Some important factors, such as the nanoparticles concentration, the pH and concentration of the running buffer solution, were also investigated on the separation. Under optimized experimental conditions, all the auxins investigated can be baseline separated within 5 min with higher column performance. The method established can also be used for quantitative analysis. The relative standard deviations obtained for indole-3-acetic acid, indole butyric acid, 2,4-dichlorophenoxyacetic acid, 1-naphthaleneacetic acid were in the range of 1.6-5.7% for peak area and 0.53-1.60% for migration time. The calibration curves obtained from the peaks areas for auxins were linear in the range of 0.1-80 mg/L with the correlation coefficients of 0.994-0.999. The limit of detection (S/N = 3) was 11-75 µg/L. The developed method was also successfully used for the determination of auxins in fruits and vegetables samples with good recoveries.

Clinical significance of serum oxidative stress and serum uric acid levels before surgery for hepatitis B-related liver cancer.

BACKGROUND: The incidence and mortality of liver cancer are among the highest of all malignant tumors in China. The high recurrence rate after conventional hepatectomy is worrying. There is a lack of effective prognostic indicators for liver cancer. AIM: To explore the clinical significance of preoperative serum oxidative stress and serum uric acid (UA) levels in hepatitis B-related liver cancer. METHODS: The medical records of 110 hepatitis B-related liver cancer patients who underwent hepatectomy in Gansu Provincial Hospital were retrospectively analyzed. Recurrence in patients within 3 years after surgery was determined. The logistic regression model and Pearson or Spearman correlation were used to analyze the correlation between oxidative stress level and UA, and the recurrence of hepatitis B-related liver cancer. RESULTS: Compared with the non-recurrence group, the levels of superoxide dismutase (SOD) and glutathione (GSH) in the recurrence group were lower and the levels of malondialdehyde (MDA) and UA were higher (all P < 0.05). UA, SOD, MDA, and GSH were risk factors for postoperative recurrence in hepatitis B-related liver cancer patients (P < 0.05). UA was positively correlated with MDA (r = 0.395, P < 0.001) and negatively correlated with GSH (r = -0.204, P = 0.032). The area under the receiver operating characteristic curve (AUC) of SOD, MDA, GSH, and UA in predicting the prognosis was 0.276, 0.910, 0.199, and 0.784, respectively (all P < 0.001). CONCLUSION: The preoperative serum SOD, GSH, MDA, and UA levels had significant predictive effects on postoperative recurrence of hepatitis B-related liver cancer.

Diamino moiety functionalized silica nanoparticles as pseudostationary phase in capillary electrochromatography separation of plant auxins.

A novel and simple method for the preparation of silica nanoparticles having surface-functionalized diamino moiety (dASNPs) was reported in our paper and characterized using scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectrometry, and thermogravimetry techniques. To test this method practically, in this contribution we describe the enhanced separation of four plant auxins - indole-3-acetic acid (IAA), indole-3-butyric acid (IBA), 2,4-dichlorophenoxyacetic acid (dCPAA), and 2-(1-naphthyl) acetic acid (NAA) - by capillary electrochromatography using diamino moiety functionalized silica nanoparticles as pseudostationary phase (PSP) in the running buffer. The effect of pH, buffer concentration, and diamino moiety functionalized silica nanoparticles concentration on the selectivity of separation was investigated. A combination of the nanoparticles and running buffer reversed the electroosmotic direction making possible the rapid and efficient separation of the auxins from the auxins migrated in the same direction with the EOF under optimum experimental conditions. A good resolution of four auxins was obtained within 5.5 min under optimum experimental conditions. The precision (RSD, n = 5) was in the range of 0.72-0.91% and 1.89-2.23% for migration time and peak area response, respectively. The detection limits were 0.48, 0.44, 0.46, and 0.42 µM for NAA, IBA, IAA, and dCPAA, respectively. Furthermore, the method was successfully tested for the determination of IAA in the grapes.

The involvement of occipital and inferior frontal cortex in the phonological learning of Chinese characters.

Neural changes related to the learning of the pronunciation of Chinese characters in English speakers were examined using fMRI. We examined the item-specific learning effects for trained characters and the generalization of phonetic knowledge to novel transfer characters that shared a phonetic radical (part of a character that gives a clue to the whole character's pronunciation) with trained characters. Behavioral results showed that shared phonetic information improved performance for transfer characters. Neuroimaging results for trained characters over learning found increased activation in the right lingual gyrus, and greater activation enhancement in the left inferior frontal gyrus (Brodmann's area 44) was correlated with higher accuracy improvement. Moreover, greater activation for transfer characters in these two regions at the late stage of training was correlated with better knowledge of the phonetic radical in a delayed recall test. The current study suggests that the right lingual gyrus and the left inferior frontal gyrus are crucial for the learning of Chinese characters and the generalization of that knowledge to novel characters. Left inferior frontal gyrus is likely involved in phonological segmentation, whereas right lingual gyrus may subserve processing visual-orthographic information.

Preparation of silica-based nanoparticle having surface-bound octanoyl-aminopropyl moieties and its applications for the capillary electrochromatography separation of charged and neutral compounds.

A kind of novel amphiphilic silica-based nanoparticle having surface-bound octanoyl-aminopropyl moieties (OA-NP) with the diameter of ~250 nm was successfully prepared and characterized by elemental analysis, Fourier transform infrared spectrometry. The potential use of OA-NP as pseudostationary phase in capillary electrochromatography for the separation of aromatic acids, basic, and neutral compounds was investigated. Five aromatic acids were separated rapidly with high column efficiency as they migrate in the same direction with the EOF under optimum experimental conditions. Under a running buffer with the composition of 40% methanol, 10 mM phosphate buffer (pH 5.5) with 1.0 mg/mL OA-NPs added, basic compounds investigated were baseline resolved with relatively symmetrical peaks. Due to the existence of polar acyl amide group on the surface of OA-NPs, "silanol effect" that occurs between the positively charged basic analytes and the silanols of the capillary column was greatly suppressed. Furthermore, the newly synthesized OA-NPs were also tried for the separation of some neutral analytes, and satisfactory separations were obtained.

On-line preconcentration and enantioseparation of thalidomide racemates by CEC with the hyphenation of octyl and norvancomycin monoliths.

A method was developed for simultaneous preconcentration and chiral separation of thalidomide enantiomers in human urine by CEC in combination with self-concentration and solvent gradient effects. A 4 cm long octyl (C8) monolithic column was hyphenated with a 15 cm long norvancomycin (NVC)-bonded monolithic column via a fluorinated ethylene-propylene interface. Sample solution was injected into the C8 monolithic column, the two thalidomide enantiomers were first preconcentrated on the C8 monolithic column, and then separated with a further concentration on the NVC-bonded monolithic column by CEC. Injection of 34.8 mm plug of sample solution gave 278- and 298-fold enhancement in sensitivity, and detection limits of 90 and 94 microg/L for the two thalidomide enantiomers. Peak areas of the two isomers were linear in a range of 0.5-50 mg/L. The precision for five replicate injections of 10 mg/L were 0.8-0.9 and 1.1-2.3% for the migration time and peak height, respectively. The developed method was applied to the determination of racemic thalidomide in spiked human urine samples.

Item-specific and generalization effects on brain activation when learning Chinese characters.

Neural changes related to learning of the meaning of Chinese characters in English speakers were examined using functional magnetic resonance imaging (fMRI). We examined item specific learning effects for trained characters, but also the generalization of semantic knowledge to novel transfer characters that shared a semantic radical (part of a character that gives a clue to word meaning, e.g. water for lake) with trained characters. Behavioral results show that acquired semantic knowledge improves performance for both trained and transfer characters. Neuroimaging results show that the left fusiform gyrus plays a central role in the visual processing of orthographic information in characters. The left superior parietal cortex seems to play a crucial role in learning the visual-spatial aspects of the characters because it shows learning related decreases for trained characters, is correlated with behavioral improvement from early to late in learning for the trained characters, and is correlated with better long-term retention for the transfer characters. The inferior frontal gyrus seems to be associated with the efficiency of retrieving and manipulating semantic representations because there are learning related decreases for trained characters and this decrease is correlated with greater behavioral improvement from early to late in learning.

Capillary electrochromatographic separation of racemates on a norvancomycin-bonded monolithic column under reversed-phase conditions.

Following a modified sol-gel process, a silica backbone was prepared in a fused-silica capillary, and it was then chemically modified with a glycopeptide antibiotic, norvancomycin (NVC), by a one-step in situ derivatization process. Several selected neutral and basic racemates were assessed on this column under reversed-phase conditions. The influences of pH and composition of mobile phase on enantioselectivity factor (alpha) and resolution (R(s)) were also evaluated. A comparison was made between the NVC-bonded column with other similar capillary columns in published papers to demonstrate its better enantioselectivity. Furthermore, warfarin was chosen as model compound to study the self-preconcentration effect of racemates on this column. The preconcentration is marked in terms of peak heights, with up to 8-10-fold increase for the enantiomers of warfarin without obvious loss in column performance. Experimental data also show that the extent of preconcentration follows the retention factor (k) for a given enantiomer.

Specialization of phonological and semantic processing in Chinese word reading.

The purpose of this study was to examine the neurocognitive network for processing visual word forms in native Chinese speakers using functional magnetic resonance imaging (fMRI). In order to compare the processing of phonological and semantic representations, we developed parallel rhyming and meaning association judgment tasks that required explicit access and manipulation of these representations. Subjects showed activation in left inferior/middle frontal gyri, bilateral medial frontal gyri, bilateral middle occipital/fusiform gyri, and bilateral cerebella for both the rhyming and meaning tasks. A direct comparison of the tasks revealed that the rhyming task showed more activation in the posterior dorsal region of the inferior/middle frontal gyrus (BA 9/44) and in the inferior parietal lobule (BA 40). The meaning task showed more activation in the anterior ventral region of the inferior/middle frontal gyrus (BA 47) and in the superior/middle temporal gyrus (BA 22,21). These findings are consistent with previous studies in English that suggest specialization of inferior frontal regions for the access and manipulation of phonological vs. semantic representations, but also suggest that this specialization extends to the middle frontal gyrus for Chinese. These findings are also consistent with the suggestion that the left middle temporal gyrus is involved in representing semantic information and the left inferior parietal lobule is involved in mapping between orthographic and phonological representations.

fMRI evidence for the automatic phonological activation of briefly presented words.

Functional magnetic resonance imaging was used to investigate whether people generate the phonology of briefly presented words that they do not attend. This was done in Chinese by examining the effect of orthography-phonology regularity (i.e., how predictable the phonology of a word is from its components rather than whole-word form) with high- and low-frequency words, and by using a task that diverted participants' attention to a mask, rather than the words. The results showed that there was a significant interaction between regularity and word frequency in blood oxygen level-dependent (BOLD) signal, which mirrored the pattern found in behavioral data. Specifically, for low-frequency characters, bilateral fusiform gyri, the posterior superior temporal gyrus, and inferior parietal regions were more active when using irregular compared to regular characters. There were no significant differences when high-frequency characters were used. These results support the possibility that at least for low-frequency words, phonology is automatically generated when reading, even when people do not attend to the words and even in a language where the orthography-phonology mapping is extremely irregular.

Simultaneous separation and determination of five organic acids in beverages and fruits by capillary electrophoresis using diamino moiety functionalized silica nanoparticles as pseudostationary phase.

A kind of novel diamino moiety functionalized silica nanoparticles with the diameter of ~110 nm was successfully prepared and characterised by transmission electron microscope (TEM) and elemental analysis. Capillary electrophoresis (CE) with this kind of nanoparticles as pseudostationary phase was developed for the simultaneous analysis of five organic acids in beverage and fruit samples. The effects of pH, buffer concentration, and nanoparticles concentration on separation were carefully investigated. Five organic acids were baseline separated in 5 min under optimum experimental conditions. The precisions for five replicate separations of a standard mixture solution were 2.71-6.13% for peak area and 1.22-1.93% for migration time respectively. The detection limits were 7.5, 0.15, 0.23, 0.33 and 10.0mg/L for citric acid, salicylic acid, benzoic acid, sorbic acid and ascorbic acid, respectively. The developed method was applied to the simultaneous analysis of five analytes in beverage and fruit samples and certified reference materials with satisfactory results.

Water-compatible surface molecularly imprinted silica nanoparticles as pseudostationary phase in electrokinetic chromatography for the enantioseparation of tryptophan.

A novel approach based on surface molecularly imprinted technique is demonstrated for the synthesis of surface molecularly imprinted silica nanoparticles (MI-SiNPs) in aqueous media, using l-tryptophan (l-Trp) as template molecule. The MI-SiNPs were fully characterized by transmission electron microscopy (TEM), thermo gravimetric analysis (TGA) and atomic force microscopy (AFM), and the results showed MI-SiNPs thus prepared were uniform in particle size (∼87nm) with a distinct core-shell structure with shell thickness of ∼7nm. The terminal carboxyl groups endowed the MI-SiNPs with good water-compatibility, and so good suspension stability for MI-SiNPs in water-rich buffer solutions can be easily achieved without the addition of any other reagents. When MI-SiNPs were used as pseudostationary phases (PSPs) in electrokinetic chromatography (EKC) for the enantioseparation of Trp, a resolution of 2.73 can be achieved in less than 10min with symmetric peaks. These excellent separation features are mainly attributed to the fast mass transfer and good accessibility of the interaction sites locating at the surface of the MI-SiNPs. The effects of some important separation factors, e.g., pH and concentration of buffer solution, content of MI-SiNPs added, content of organic modifier in buffer solution, on the enantioseparation of Trp were studied, and an optimum separation condition of 30% (v/v) acetonitrile in 20mmolL(-1) phosphate buffer (pH 7.0), with 0.50mgmL(-1) MI-SiNPs added was ultimately selected.

Amphiphilic silica nanoparticles as pseudostationary phase for capillary electrophoresis separation.

Amphiphilic silica nanoparticles surface-functionalized by 3-aminopropyltriethoxysilane (APTES) and octyltriethoxylsilane (OTES) were successfully prepared and characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectrometry (FT-IR) and thermogravimetry (TG) techniques. The potential use of these bifunctionalized nanoparticles as pseudostationary phases (PSPs) in capillary electrophoresis (CE) for the separation of charged and neutral compounds was evaluated in terms of their suitability. As expected, fast separation of representative aromatic acids was fulfilled with high separation efficiency, because they migrate in the same direction with the electroosmotic flow (EOF) under optimum experimental conditions. Using a buffer solution of 30mmol/L phosphate (pH 3.0) in the presence of 0.5mg/mL of the synthesized bifunctionalized nanoparticles, the investigated basic compounds were baseline-resolved with symmetrical peaks. Due to the existence of amino groups on the surface of nanoparticles, "silanol effect" that occurs between positively charged basic analytes and the silanols on the inner surface of capillary was greatly suppressed. Furthermore, the separation systems also exhibited reversed-phase (RP) behavior when neutral analytes were tested.

Cloud point extraction for the determination of As(III) in water samples by electrothermal atomic absorption spectrometry.

Cloud point extraction was applied as a preconcentration step for electrothermal atomic absorption spectrometry (ETAAS) determination of As(III) in aqueous solutions. After complexation with ammonium pyrrolidinedithiocarbamate, the analyte was quantitatively extracted to the surfactant-rich phase in the non-ionic surfactant octylphenoxypolyethoxyethanol (Triton X-114) after centrifugation. 0.1molL(-1) HNO(3) in methanol was added to the surfactant-rich phase before ETAAS determination. The precision (R.S.D.) for 11 replicate determinations of 5.0mugL(-1) of As(III) was 3.0%. The concentration factor, which is defined as the concentration ratio of the analyte in the final diluted surfactant-rich extract ready for ETAAS determination and in the initial solution, was 36 for As(III). The linear concentration range was from 0.1 to 20mugL(-1). The developed method was applied to the determination of As(III) in lake water and river water.

Chiral separation of enantiomers of amino acid derivatives by high-performance liquid chromatography on a norvancomycin-bonded chiral stationary phase.

A novel norvancomycin-bonded chiral stationary phase (NVC-CSP) was synthesized by using the chiral selector of norvancomycin. The chiral separation of enantiomers of several dansyl-amino acids by high-performance liquid chromatography (HPLC) in the reversed-phase mode is described. The effects of some parameters, such as organic modifier concentration, column temperature, pH and flow rate of the mobile phase, on the retention and enantioselectivity were investigated. The study showed that ionic, as well as hydrophobic interactions were engaged between the analyte and macrocycle in this chromatographic system. Increasing pH of buffers usually improved the chiral resolution for dansyl-alpha-amino-n-butyric acid (Dns-But), dansyl-methionine (Dns-Met) and dansyl-threonine (Dns-Thr), but not for dansyl-glutamic acid (Dns-Glu) which contains two carboxylic groups in its molecular structure. The natural logarithms of selectivity factors (lnalpha) of all the investigated compounds depended linearly on the reciprocal of temperature (1/T), most processes of enantioseparation were controlled enthalpically. Interestingly, the process of enantioseparaton for dansyl-threonine was enthalpy-controlled at pH of 3.5, while at pH of 7.0, it was entropy-controlled according to thermodynamic parameters Delta(R,S)DeltaH degrees and Delta(R,S)DeltaS degrees afforded by Van't Hoff plots. In order to get baseline separation for all the solutes researched, norvancomycin was also used as a chiral mobile phase additive. In combination with the NVC-CSP, remarkable increases in enanselectivity were observed for all the compounds, as the result of a "synergistic" effect.

[New species of selectors of chiral stationary phase in high performance liquid chromatography--macrocyclic antibiotics].

The recent development and applications of chiral stationary phase (CSP) of macrocyclic antibiotics are reviewed. The characteristics of its chiral separation are discussed according to the structures and the comparisons are made between macrocyclic antibiotics-CSPs and the other CSPs.

Neural basis of the non-attentional processing of briefly presented words.

The neural basis of the automatic activation of words was investigated in an fMRI study. In the study, words were presented briefly (51 or 151 msec) followed by a mask. To prevent attentional processing, subjects attended to the masks and not the words, and were required to make perceptual judgment about the masks. We found that a distributed neural network (including the frontal, temporal, occipital, parietal lobes, and the cerebellum) was activated during non-attentional processing of words in both exposure durations. A significant main effect of presentation duration was found in bilateral cerebellum and the right fusiform gyrus, suggesting their role in the later (151 msec) processing of words. In addition, a significant interaction between presentation duration and word frequency was obtained. When the presentation duration was 151 msec, no significant difference in activation was found between high- and low-frequency words. Alternatively, when the presentation duration was 51 msec, high-frequency words evoked significantly greater activation in bilateral fusiform gyri, cerebellum, right inferior parietal lobe, medial frontal gyrus (BA 45/46/9), and the right temporal-occipital junction (BA 21/37). These results suggest that these regions are sensitive to word frequency, and are related to both the attentional and non-attentional access of lexical representations.