A reusable chronocoulometric adenosine triphosphate (ATP)-aptamer sensor was developed in this work.A short chain of DNA marked as cDNA containing complementary sequence was immobilized on gold electrode based on Au-S self-assembly.The ATP aptamer was hybridized with cDNA.The surface-confined DNA could bind with [Ru(NH3)63+ (RuHex) in the electrolyte via electrostatic interaction.Upon target ATP binding, the aptamer confined onto electrode surface was disassociated from the cDNA oligonucleotides into the solution.Such surface density change of DNA lead to the decrease of chronocoulometric signal for the RuHex which confined on the electrode surface.The chronocoulometric signals showed a linear relationship with logrithm of ATP concentration in the range of 1 nmol/L to 100 μmol/L, and the detection limit of this aptamer sensor could reach 0.5 nmol/L (S/N=3).This aptamer sensor could be regenerated 5 times by simple steps.With this aptamer sensor, the basal level of ATP in the brain cortex micorodialysate was determined to be 19.2±3.7 nmol/L (n=3).

Electromagnetic Fields ; Threshold Limit Values

Objective To study the influence on STR typing for low copy number(LCN)DNA using different methods of amplifcation and detection.Methods Control DNA 9947A was diluted and then amplifled with Identifiler~(TM) or DNATyper15~(TM).The heat cycles were set to 28 or 28 add 6.Each template wag amplified three times in parallel,and then the amplified products or the product mixture of three amplifictions were deteced with 310 or 3130 Genetic Analyzer.Results The success rate of STR typing with the method 28+6 cycles was higher than that of 28 cycles.There are no correlation between the allele imbalance or allele dropout and STR locus.With the reduction in the amount of template DNA,allele imbalance and dropout gradually increased,and the allele dropout was more common than allele imbalance when the amount of template DNA Wag very small.When the product mixture of three amplifictions were deteced.the occurrence of allele imbalance and dropout reduce obviously.Conclusion The success rate of STR typing of LCN DNA can be obviously increased by detecting the product mixture of three amplifictions in parallel combined with the 28+6 heat cycle condition.

BACKGROUND: With the continuous development of materials science, magnesium alloy vascular stent materials have become a hot research. Because of the mechanical properties and biocompatibility of commercial magnesium alloy, it is difficult to meet the requirements of vascular stents. Therefore, effective measures to improve the sten's surface properties and comprehensive performance become the focus of research.OBJECTIVE: To study the histology and surface modification of vascular stents in rapidly solidified Mg-Zn-Y-Nd alloy.Methods: The low-zinc Mg-2Zn-0.2Y alloy with good mechanical properties and corrosion resistance was selected as the basic material, and Nd and Zn elements were added to refine the alloy stents. After the microstructure of the stent was extruded, the surface modification of the stent was completed and the comprehensive properties of the alloy were improved. The new magnesium alloy for the stent was obtained and the stent surface was modified. The metallographic microstructure, scanning electron microscopy and radiological analysis were used to study the microstructure and mechanical properties of the prepared stents. The mechanical properties of the stents were investigated by hardness and tensile tests.RESULTS AND CONCLUSION: (1) Metallographic microstructure results showed that: when Y elements were not added, the second phase of the magnesium alloy was rod-shaped, and there were a few granules embedded in the matrix. After addition of 0.5% Y elements, in the second phase of the magnesium alloy stent, the shafts were significantly reduced in number, and granules were increased in number and evenly distributed in the body. After the addition of 1% Y,the second phase number increased, a large number of dendrites were visible in the grains, and discontinuous rods existed in the second phase. After the addition of 1.5% Y, the second phase was rod-shaped, with mixture of large and local dendrites in the alloy. (2) X-ray diffraction test results: Mn-Zn-0.5Nd alloy and Mn-Zn-1.0Nd alloy contained the same phases (Mg4Zn7 and (Nd, Y) 2Zn17 phase). When the concentration of Nd increased to 1%, the new MgZn2 phase appeared in the alloy. (3) SEM & EDS test results of modified magnesium alloy showed that after magnesium alloy modification, the second phase contained Zn, Nd and Y elements, and their contents were very close. EDS analysis showed that after the addition of Zr elements, the level of Zn elements in the lamellar second phase decreased significantly, and the level of Nd and Y elements increased, indicating a more stable performance. (4) Micro-hardness test results showed that with the increasing of the content of magnesium alloy, the alloy microhardness increased. (5)Tensile test results showed that the tensile strength and yield strength of the Mg-Zn-Y-0.5Nd-Zr stent were significantly higher than those of Mg-Zn-Y-0.5Nd, Mg-Zn-Y-1.0Nd,Mg-Zn-Y-1.0Nd-Zr stents (P < 0.05); and the elongation at break of Mg-Zn-Y-0.5Nd-Zr and Mg-Zn-Y-1.0Nd-Zr stents was significantly higher than that of Mg-Zn-Y-1.0Nd and Mg-Zn-Y-0.5Nd stents (P < 0.05). To conclude, with Mg-2Zn-0.2Y as core materials, the material modification could be completed by the addition of Nd and Zn elements, and the surface modification could be implemented by extruding and refining the stent microstructure. The modified material has excellent properties.

The extended service in domestic and foreign medical libraries was summarized according to the trans-formation of medical library and the need of public health information followed by a description of some typical cases of extended service provided by MedlinePlus website , Disaster Medical Information Management Research Center , and patient libraries in order to provide the reference for domestic medical libraries to cary out their extended service .

Objective To investigate the changes of serum nerve growth factor(NGF) and interleukin(IL)-15 levels in children with mycoplasma pneumoniae pneumonia(MPP) and its clinical significance.Methods Using the antibody sandwich ELISA method to measure the serum NGF and IL-15 levels in 65 cases of MPP (MPP group,which contains two groups:the severe group contains 25 patients and the mild group contains 40 patients) and 50 cases of healthy children (normal control group).Results The serum NGF,IL-15 levels in the acute phase of MPP group were (157.62 ± 33.45) pg/ml and (242.51 ± 60.04) pg/ml,and in the recovery period were (99.58 ±21.29) pg/ml and (145.90 ±50.25) pg/ml,they were all significantly higher than the normal control group [(29.86-± 11.74) pg/ml and (108.86 ± 21.14) pg/ml,P ＜ 0.05].The serum NGF,IL-15 of the acute phase were also higher than the recovery period (P ＜0.05).In the acute phase of MPP,serum NGF,IL-15 levels in the severe group were significantly higher than in the mild group [(204.38±27.52) pg/ml vs (128.39 ±22.07) pg/ml,(288.58 ±55.33) pg/ml vs (213.71 ±42.69) pg/ml],and the differences were statistically significant (P ＜ 0.05) ; in the recovery period of MPP group,the serum NGF,IL-15 levels of severe group were higher than the mild group,but the difference was not statistically significant (P ＞0.05).Conclusion The serum levels of NGF,IL-15 in the mycoplasma pneumoniae infection patients are significantly increased,and they are all decreased as the disease mitigation.It is prompted that NGF and IL-15 participate in the pathogenesis of infection by mycoplasma pneumoniae.

Objective To investigat the changes of hemodynamics and arterial blood gas during the establishment of ECMO model and provide an ideal platform for the study of the mechanism of DCD protection using ECMO, a porcine model of controlled donors of cardiac death (CDCD) with extracorporeal support was established in the paper. Methods Eight domestic crossbred pigs were anes-thetized, atracurium (1mg/kg) and heparin (150~200 U/kg) was administered and the ventilator was discontinued while the animal was under deep anesthesia to kill the animal.Meanwhile, blood was drained from the left jugular vein catheter into the ECMO circuit and re-turned into the left femoral artery to establish the porcine model of CDCD with extracorporeal support . The average blood press and arterial blood gas were ministered at normal, cardiac arrest and ECMO supporting 1 h, 3 h and 5 h. Results The model of CDCD with extra-corporeal support was established successfully.Two animals restored the beating of the heart and the high doses of potassium chloride were given untill cardiac arrest during extracorporeal support.Blood gases throughout the apneic time showed a severe hypoxemia and acidosis, pH and PaO2 reduced to 7.09 ±0.24 and 5.3 ±0.93mmHg respective-ly, which can be improved during extracorporeal support.MAP and PaO2 were maintained over 300mmHg and 65mmHg respectively. Conclusion A new porcine model of controlled donors of cardiacdeath with extracorporeal support has been successfully established and showed to be feasible for related pathophysiological research work.

Objective To investigate the expression of apoptosis-related neuclosome assembly protein-1(NAP-1) gene in related brain region of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP) treated mice and beta-amyloid treated rats. Methods The animal models with central nervous system degeneration were established by consecutive administration of MPTP to C57BL mice and injection of beta-amyloid to brain ventricular of SD rats. The RNA in striatum and substantia nigra of mice and the RNA in cortex and hippocampus of rats were extracted. The levels of NAP-1 mRNA in these samples were estimated by RT-PCR. Results For mice, the expression of NAP-1 were decreased after MPTP treatment in substantia nigra, while its expression showed no significant change in striatum. In contrast, no effect on NAP-1 gene expression by beta-amyloid injection can be detected in cortex and hippocampus of rats. Conclusions The apoptosis of dopaminergic neurons in nigrostriatal pathway after MPTP treatment may be related to the expression of NAP-1 gene. But the mechanism of neurodegeneration after beta-amyloid injection in rats may be different.

Abstract Type 2 diabetes mellitus (T2DM) is characterized by long duration of disease and latent onset. Risk prediction models have shown potential for f early diagnosis and early treatment of diseases and formulation of targeted interventions. There is an increase in researches on risk prediction models for T2DM during the recent years, which provides the basis for precision tertiary prevention of T2DM; however, most studies suffer from problems of small sample size, complicated variables and difficulty in extensive applications. This review summarizes the risk prediction models for T2DM based on economic and easily available routine physical examination indicators, so as to provide insights into further studies on easy-to-perform and -popularize risk prediction models for T2DM.