Determination of 240 Pu/ 239 Pu in Plutonium-containing Particle by Laser Ablation Multiple Collector Inductively Coupled Plasma Mass Spectrometry / 分析化学

The isotopic fingerprints of plutonium are extremely important for nuclear safeguards and nuclear forensics. An analytical method was developed for direct determination of 240 Pu / 239 Pu ratio in plutonium-containing particles by laser ablation multiple collector inductively coupled plasma mass spectrometry ( LA-MC-ICP-MS). The risk of ablated particles leakage was reduced by leak detection, exhaust hood, and swiping the laser cell. Scanning mobility particle sizer (SMPS) was used to measure the effect of ablation parameters on the size distribution of ablated particles. The results showed that the majority of ablation material presented as particles from 40 -500 nm and the sweep time after laser ablation should be longer than 15 min. The particle size was evaluated to guide LA-MC-ICP-MS system. By using external normalization method for correction of the mass fractionation correction factor and ion counter efficiencies measured by nebulizer-coupled MC-ICP-MS, a LA-MC-ICP-MS method was established for analysis of 239 Pu / 240 Pu ratio in plutonium particles. Spot size, ablation rate and laser dwell time were set at 30 μm, 5 Hz and 5 s, respectively. Laser energy density was controlled to ensure that the intensities of 239 Pu for plutonium-containing particles were about 2×104 cps and 2×105 cps, respectively. The analytical results showed that the relative uncertainties for 239 Pu / 240 Pu was less than 1. 4% ( n = 6), and the measured value deviated by less than 4. 7% from the reference value. The time for adjusting system and determining 239 Pu / 240 Pu ratio in single plutonium particle was 9 h and 0. 5 h, respectively. The results demonstrated that this technique was rapid, precise and accurate, and could be used for determination of 239 Pu / 240 Pu in plutonium-containing particles.

Relationship between arterial atheromatous plaque morphology and platelet-associated miR-126 and miR-223 expressions

Objective: To study the expression of miR-126 and miR-223 in platelet of rabbit arterial plaque models, and explore its correlation with plaque morphology. Methods: Rabbit arterial plaque models were established, peripheral blood of models and control animals was collected. Plaque morphologies were divided into type I, type II and type III based on angiography plaque morphology and Ambrose method. Platelet isolation kit was applied to isolate and purify peripheral blood platelets, CD45 immunomagnetic beads were used to remove the residual white blood cells. The miRNAs of platelets was extracted by miRNA Isolation Kit, and expressions of miR-126 and miR-223 of the platelets samples were detected by Real-time PCR. The correlation between plaque morphology and platelet-associated miR-126 and miR-223 expressions were analyzed. Expressions of target gene VCAM-1 and P2Y12 receptors of miR-126 and miR-223 in the atherosclerosis plaque of rabbit model were detected by Western blot. Results: Relative expression levels of miR-126 and miR-223 in the model group were 0.27±0.10 and 0.71±0.14, respectively. Plaque morphology was divided into types I, II and III; and miR-126 and miR-223 expression levels were detected in each type. Expression levels of miR-126 in each type were 0.42±0.07, 0.17±0.11 and 0.22±0.15, respectively; and expression levels of miR-223 in each type are 0.68±0.02, 0.57±0.06 and 0.88±0.10, respectively. Relative to the control group, miR-126 and miR-223 known target genes in VCAM-1 and P2Y12 receptors increased platelets in rabbit atherosclerotic plaque models (P<0.05). Conclusions: Relative to normal control animals, miR-126 and miR-223 platelets were reduced in the rabbit atherosclerotic plaque model group (P<0.05). In the type II plaque morphology group, miR-126 was greatly reduced; and there is no significant correlation between miR-223 and plaque morphology.

Relationship between arterial atheromatous plaque morphology and platelet-associated miR-126 and miR-223 expressions

OBJECTIVE@#To study the expression of miR-126 and miR-223 in platelet of rabbit arterial plaque models, and explore its correlation with plaque morphology.@*METHODS@#Rabbit arterial plaque models were established, peripheral blood of models and control animals was collected. Plaque morphologies were divided into type I, type II and type III based on angiography plaque morphology and Ambrose method. Platelet isolation kit was applied to isolate and purify peripheral blood platelets, CD45 immunomagnetic beads were used to remove the residual white blood cells. The miRNAs of platelets was extracted by miRNA Isolation Kit, and expressions of miR-126 and miR-223 of the platelets samples were detected by Real-time PCR. The correlation between plaque morphology and platelet-associated miR-126 and miR-223 expressions were analyzed. Expressions of target gene VCAM-1 and P2Y12 receptors of miR-126 and miR-223 in the atherosclerosis plaque of rabbit model were detected by Western blot.@*RESULTS@#Relative expression levels of miR-126 and miR-223 in the model group were 0.27±0.10 and 0.71±0.14, respectively. Plaque morphology was divided into types I, II and III; and miR-126 and miR-223 expression levels were detected in each type. Expression levels of miR-126 in each type were 0.42±0.07, 0.17±0.11 and 0.22±0.15, respectively; and expression levels of miR-223 in each type are 0.68±0.02, 0.57±0.06 and 0.88±0.10, respectively. Relative to the control group, miR-126 and miR-223 known target genes in VCAM-1 and P2Y12 receptors increased platelets in rabbit atherosclerotic plaque models (P<0.05).@*CONCLUSIONS@#Relative to normal control animals, miR-126 and miR-223 platelets were reduced in the rabbit atherosclerotic plaque model group (P<0.05). In the type II plaque morphology group, miR-126 was greatly reduced; and there is no significant correlation between miR-223 and plaque morphology.