Dual-frequency ultrasound assisted-enzyme digestion coupled with atomic fluorescence spectrometry as a green and efficient tool for cadmium detection in rice flour samples.

A sample treatment technique based on a duel frequency ultrasonic device for enzymatic digestion of rice is reported. The ultrasonic device combines a high intensity ultrasonic probe and the temperature control function of ultrasonic water bath, which can effectively extract cadmium from rice within only 160 s under the optimized conditions. Compared with the traditional ultrasonic assisted enzymatic digestion, the new method not only shortens the time significantly (e.g., from the 90 min of ultrasonic water bath to the present few minutes), but also increases the extraction efficiency of cadmium (such as ~ 75% from ultrasonic probe to app. 100%). Through the optimization of ultrasonic mode, ultrasonic frequency, power and the type of enzyme, we found that enzyme played a dominant role in ultrasound assisted enzymatic digestion. Compared with a-amylase and pepsin, trypsin is more suitable for the extraction of cadmium from rice. Furthermore, ultrasound energy is beneficial to enzymatic hydrolysis of bimolecular, and this promotion is related to the frequency of ultrasound. The reliability of this method was evaluated by analyzing the content of cadmium in the certified reference materials (CRMs, GBW10045, GBW08510, GBW08511 and GBW08512) based on atomic fluorescence spectrometry combined with a modified chemical vapor generation. The proposed method has been applied satisfactorily in the determination of Cd in several rice samples.

Highly efficient electrocatalytic vapor generation of methylmercury based on the gold particles deposited glassy carbon electrode: A typical application for sensitive mercury speciation analysis in fish samples.

A gold particle deposited glassy carbon electrode (Au/GCE) was first used in electrochemical vapor generation (ECVG) technology and demonstrated to have excellent catalytic property for the electrochemical conversion process of aqueous mercury, especially for methylmercury (CH3Hg+), to gaseous mercury. Systematical research has shown that the highly consistent or distinct difference between the atomic fluorescence spectroscopy signals of CH3Hg+ and Hg2+ can be achieved by controlling the electrolytic parameters of ECVG. Hereby, a new green and accurate method for mercury speciation analysis based on the distinguishing electrochemical reaction behavior of Hg2+ and CH3Hg+ on the modified electrode was firstly established. Furthermore, electrochemical impedance spectra and the square wave voltammetry displayed that the ECVG reaction of CH3Hg+ may belong to the electrocatalytic mechanism. Under the selected conditions, the limits of detection of Hg2+ and CH3Hg+ are 5.3 ng L-1 and 4.4 ng L-1 for liquid samples and 0.53 pg mg-1 and 0.44 pg mg-1 for solid samples, respectively. The precision of the 5 measurements is less than 6% within the concentration of Hg2+ and CH3Hg+ ranging from 0.2 to 15.0 µg L-1. The accuracy and practicability of the proposed method was verified by analyzing the mercury content in the certified reference material and several fish as well as water samples.

Microglia activity modulated by T cell Ig and mucin domain protein 3 (Tim-3).

Microglia are the main innate immune cells in the central nervous system that are actively involved in maintaining brain homeostasis and diseases. T cell Ig and mucin domain protein 3 (Tim-3) plays critical roles in both the adaptive and the innate immune system and is an emerging therapeutic target for treatment of various disorders. In the brain Tim-3 is specifically expressed on microglia but its functional role is unclear. Here, we showed that Tim-3 was up-regulated on microglia by ATP or LPS stimulation. Tim-3 activation with antibodies increased microglia expression of TGF-ß, TNF-α and IL-1ß. Blocking of Tim-3 with antibodies decreased the microglial phagocytosis of apoptotic neurons. Tim-3 blocking alleviated the detrimental effect of microglia on neurons and promoted NG2 cell differentiation in co-cultures. Finally, MAPKs namely ERK1/2 and JNK proteins were phosphorylated upon Tim-3 activation in microglia. Data indicated that Tim-3 modulates microglia activity and regulates the interaction of microglia-neural cells.

Simplified protocol for isolation of multipotential NG2 cells from postnatal mouse.

BACKGROUND: The functions of NG2 cells have attracted much attention since they were identified. At present, our understanding of their properties and functions is still limited due to the lack of an easy protocol for isolating them from mice. NEW METHOD: In the present study, in postnatal mouse cortical tissue cultures, cell confluence was achieved at DIV 6-8 by frequently changing the medium in the absence of viable neurons, and abundant NG2 cells grew on top of the astrocyte layer before microglia started to thrive. Thus, we developed a simple protocol to separate mouse NG2 cells by shaking the cultures on an orbital shaker at 37 °C for only 3-4h. RESULTS: The yield and purity of NG2 cells were sufficiently high, and the cells displayed immunological and electrophysiological phenotypes typical of NG2 cells. They expressed a large delayed-rectifier K+ current (ID) and a transient A-type K+ current (IA) that were electrophysiologically different from astrocytes and neurons. They showed significantly enhanced chemo-attractive migration after application of GABA. They also showed properties of multipotential neuronal precursor cells and were capable of generating oligodendrocytes (54.2±8.1%), neurons (up to 13.3±6.8%), and astrocytes (93.9±4.3%) under defined conditions. Comparison with Existing Method(s): When compared to other methods available for the isolation of mouse NG2 cells, the procedure we present is simple, relatively fast, and economical. CONCLUSIONS: Overall, we present evidence that this new method for isolating NG2 cells from postnatal mice is simple, economical, and effective.

Four-corner arthrodesis concentrator of Ni-Ti memory alloy for carpal collapse.

OBJECTIVE: To evaluate the treatment outcomes of a four-corner arthrodesis concentrator of Ni-Ti memory alloy for carpal collapse. METHODS: From August 2006 to November 2009, 13 patients with carpal collapse underwent scaphoid excision and four-corner (capitate, lunate, triquetrum and hamate) arthrodesis using a four-corner arthrodesis concentrator of Ni-Ti memory alloy. The mean follow-up time was 26.5 months (range, 7-38 months). Various wrist parameters, including the grip strength, range of wrist movements and degree of pain (visual analogue scales) were recorded and compared before and after surgery. RESULTS: The average fusion time was 2.3 months (range, 2-4 months). Neither non-union nor wound infection was found in any of the patients. By the sixth month postoperatively, the grip strength had reached an average of 32.49 ± 6.21 kg with a range of 22.3-39.7 kg, this being 80.8% of that found on the healthy side. The range of motion reached over 53.0% of that of the healthy side. Preoperatively and at 6 months postoperatively, the mean pain scores were (4.46 ± 1.27) and 1.31 ± 0.95, respectively, when resting (P < 0.05), and 7.00 ± 1.41 and 2.62 ± 1.26, respectively, when weight-bearing (P < 0.05). The mean value of the Krimmer wrist score was 79.2 (range, 64-84). The rate of excellent and fine results was 84.6% (11/13), being excellent in three cases, good in eight and fair in two. CONCLUSION: Four-corner arthrodesis using a four-corner arthrodesis concentrator of Ni-Ti memory alloy is an effective method for treating carpal collapse and preserving most wrist function.

[Study on the efficacy of hepatitis B virus vaccination and its influencing factors among children in rural area of Jiangsu province].

OBJECTIVE: To evaluate the efficacy of hepatitis B viruse (HBV) vaccination and its influencing factors among children in rural area of Jiangsu province. METHODS: Twenty-five hundred and twenty-two children born after 1998 in rural area were selected as the study population using multistage cluster sampling method. HBsAg and anti-HBs were detected by enzyme linked immunoassay (ELISA) and radio-immunoassay (RIA), respectively. Anti-HBs negative children were boosted using different hepatitis B vaccines and the efficacy was compared. Factors causing HBV infection in HBsAg positive children were also investigated. RESULTS: HBsAg positive rates in 1-7 year olds were 0.28%-1.28%, and the anti-HBs positive rates decreased from 76.7% to 45.5%. The HBsAg positive rate in children not timely vaccinated was significantly higher than those with HBV vaccine injection within 24 hours after birth (1.4% vs. 0.5%, P = 0.031). More than 90% of the anti-HBs negative children had protective level of anti-HBs after boosted with HBV vaccine. CONCLUSION: HBsAg positive rate in children born after 1998 in rural area of Jiangsu province decreased significantly, with an average of 0.8%. The reason for HBsAg carriage in children might be attributed to mother-to-infant transmission or not timely HBV vaccination.