Microstructure and Mechanical Properties of a New TWIP Steel under Different Heat Treatments.

The effects of solution treatment and annealing temperature on the microstructure and mechanical properties of a new TWIP steel that was alloyed from aluminum (Al), silicon (Si), vanadium (V), and molybdenum (Mo) elements were investigated by a variety of techniques such as microstructural characterization and room tensile testing. The austenite grain size grew slowly with the increase in annealing temperature. The relatively weak effect of the solution treatment and annealing temperature on the austenite grain size was attributed to the precipitation of MC and M2C, which hindered the growth of the austenite grain. The plasticity of the TWIP steel in cold rolling and annealing after solution treatment was obviously higher than that in cold rolling and annealing without solution treatment. This was because the large-size precipitates redissolved in the matrix after solution treatment, which were not retained in the subsequently annealed structure. Through cold rolling and annealing at 800 °C after solution treatment, the prepared steel exhibited excellent strength and plasticity simultaneously, with a yield strength of 877 MPa, a tensile strength of 1457 MPa, and an elongation of 46.1%. The strength improvement of the designed TWIP steel was mainly attributed to the grain refinement and precipitation strengthening.

Flexible Non-contact Electrodes for Bioelectrical Signal Monitoring.

Physiological signals such as ECG and EMG are closely related with human health and a long term monitoring of the physiological signals would be beneficial to detect possible disorders at the early stage. The wet electrodes currently used in the clinics require adhesives gels to record high-quality signals, which might cause discomfort of the patients and introduce some risk of skin allergy. Non-contact capacitive electrodes that can be operated without skin contact have been developed in previous studies, but these electrodes were rigid with electronic components on the back, which might not be an optimal solution for long term healthcare monitoring. In this study, a flexible non-contact electrode without any electronic components on both sides was designed for the long term acquisition of bioelectrical signals to maximize subject comfort. The flexible electrode was made up of multi-layer flexible printed circuits (FPC) materials and could be bent according to the local shape to achieve better non-contact capacitive coupling with the skin. The performance of the proposed flexible electrode was compared with that of the conventional wet electrodes in different signal recording conditions. The results showed that the proposed non-contact flexible electrode can capture high quality ECG and EMG signals, and its performance was comparable to the commonly used wet electrodes. This study might provide a reliable solution with great patient comfort for the long-term monitoring of biological signals.

Gastrointestinal nematodes infections and anthelmintic resistance in grazing sheep in the Eastern Inner Mongolia in China.

Gastrointestinal nematodes (GIN) are a crucial restraint to grazing sheep production worldwide. This study was conducted to determine the infections and anthelmintic resistance (AR) of GIN in pasture-based sheep in the Eastern Inner Mongolia, China. GIN eggs were tested from 600 grazing sheep feces of 10 farms using saturated saline flotation method and McMaster's method. The egg hatch test (EHT) and the faecal egg count reduction test (FECRT) were used to evaluate resistance of GIN to anthelmintics. We found that the average infection rate was 79.2% (range: 45%-100%). The grand mean faecal egg count (FEC) was 1813.2 eggs per gram (EPG) (range: 0-32400 EPG). There were significant differences in GIN infection among different breeds of sheep. The sequence of infection intensity and infection rate were Small fat tail > Ujimqin > Ju Ud (p<0.05). The 50% effective doses (ED50) of albendazole(ABZ) and levamisole (LMS) for expelling were 5.670 µg/mL and 0.302 µg/mL, respectively. The percentage reductions of avermectin (AVM), ivermectin (IVM), ABZ and LMS were 81.28%, 86.49%, 76.21% and 96.59%, respectively. The most predominant parasite genus in all four anthelmintics was Haemonchus. In these tested areas, mixed infections of GIN in grazing sheep were very common. AR, especially in Haemonchus, was a serious problem in these sheep flocks. Thus, actions are urgently required to taken to mitigate the worsening situation.

Fluoride or/and aluminum induced toxicity in guinea pig teeth with the low expression of dentine phosphoprotein.

This study investigated the damage and expression of dentine phosphoprotein (DPP) in guinea pig teeth by the administration of fluoride (F) or/and aluminum (Al). Fifty-two guinea pigs were divided randomly into four groups (control, F, Al, and F+Al). F (150 mg NaF/L) or/and Al (300 mg AlCl3 /L) were added in their drinking water for 90 days. The levels of F ion, dentine sialophosphoprotein (DSPP) gene, and DPP protein in incisor and molar were determined, respectively. The results showed that the concentrations of F ion in F and F+Al groups were increased significantly. F induced the mottled enamel and irregular abrasion of teeth, which might occur as a consequence of depressed DSPP mRNA and DPP protein expression. Both the gene and protein expressions showed obvious decrease induced by Al, especially by F. There were no synergistic effects between F and Al, instead, Al inhibited the toxicity of F.

Analysis of using interpulse intervals to generate 128-bit biometric random binary sequences for securing wireless body sensor networks.

Wireless body sensor network (WBSN), a key building block for m-Health, demands extremely stringent resource constraints and thus lightweight security methods are preferred. To minimize resource consumption, utilizing information already available to a WBSN, particularly common to different sensor nodes of a WBSN, for security purposes becomes an attractive solution. In this paper, we tested the randomness and distinctiveness of the 128-bit biometric binary sequences (BSs) generated from interpulse intervals (IPIs) of 20 healthy subjects as well as 30 patients suffered from myocardial infarction and 34 subjects with other cardiovascular diseases. The encoding time of a biometric BS on a WBSN node is on average 23 ms and memory occupation is 204 bytes for any given IPI sequence. The results from five U.S. National Institute of Standards and Technology statistical tests suggest that random biometric BSs can be generated from both healthy subjects and cardiovascular patients and can potentially be used as authentication identifiers for securing WBSNs. Ultimately, it is preferred that these biometric BSs can be used as encryption keys such that key distribution over the WBSN can be avoided.

[Effect of Chelerythrine on glucosyltransferase and water-insoluble glucan of Streptococcus mutans].

PURPOSE: To study the effect of Chelerythrine on glucosyltransferase and extra-cellular synthesis of water-insoluble glucan of Streptococcus mutans. METHODS: The Chelerythrine was used as the experimental group with concentrations ranging from 24.4microg/ml to 390.6microg/ml prepared with BHI broth medium with contained 2% glucose, and BHI culture medium was used as the control group. Streptococcus mutans was added to each group, after cultured for 24 hours in the test tubes, centrifugation was followed. The supernatants were divided into two batches. One batch of solutions was used to extract glucosyltransferase, Bradford method and Somogyi method were used to measure the content of total protein and enzyme activity, and the specific activity was calculated. Another batch of solutions was used to measure the content of water-insoluble glucan by anthrone method. The data was statistically analyzed by One-way ANOVA using SPSS13.0 software package. RESULTS: The glucosyltransferase and water-insoluble glucan of Streptococcus mutans decreased gradually with the increase of each concentration of Chelerythrine. There were highly significant differences among total sample groups, and between glucosyltransferase activity or specific activity of each experimental group and control group as well (P<0.01); Except for the group of 24.4microg/ml Chelerythrine, there were highly significant differences of water-insoluble glucan between each experimental group and control group (P<0.01).There was positive correlation between glucosyltransferase activity and water-insoluble glucan content (r=0.883, P<0.01). CONCLUSION: Chelerythrine could inhibit the glucosyltransferase and extra-cellular synthesis of water-insoluble glucan of Streptococcus mutans.

[Experimental study of the inhibitory effects of Chelidonium majus L. extractive on Streptococcus mutans in vitro].

PURPOSE: To study the inhibitory effects of Chelidonium majus L. extractive on the growth of Streptococcus mutans in vitro, and to explore its mechanism in caries prevention. METHODS: Streptococcus mutans 25175 was chosen as the experimental bacterium. The Chelidonium majus L. extractives chelidonine and chelerythrine were double diluted to different concentrations by two-fold dilution. The inhibitory effect of Streptococcus mutans was measured by slip diffusion method. The minimal inhibitory concentration(MIC) was also determined. 0.16% liquor hibitane was used as positive control. Spearman correlation was used for statistical analysis. RESULTS: Inhibition zone of Streptococcus mutans appeared in some concentration of chelerythrine, but no inhibition zone in each concentration of chelidonine. The MIC of chelerythrine was 0.78 mg/ml which determined by liquid culture medium. The concentration of chelerythrine was highly related to the inhibitory zone of Streptococcus mutans (r=0.99, P<0.01). CONCLUSION: The antibacterial activity of Chelidonium majus L. extractive chelerythrine on Streptococcus mutans was significant,and the antibacterial activity of the concentration 100 mg/ml was higher than that of 0.16% liquor hibitane (19.4 mm), indicating that chelerythrine can be used as an agent for prevention of dental caries.