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The yields of 85Krm, 87Kr and 88Kr of neutron-induced fission of 239Pu are important nuclear parameters. They have a moderate half-life, are β- decay and emission γ-rays with a certain probability, so it is appropriate to use γ-ray spectrum method to determine their yield. At present, there are few experimental data with large deviation abroad and no experimental results have been reported in China. The yield measurements of 85Krm, 87Kr and 88Kr of thermal-neutron-induced fission of 239Pu were carried out based on the irradiation of plutonium target by Xi’an Pulsed Reactor rabbit system. The purified plutonium solution was then titrated and dried to prepare the silica-encapsulated plutonium target. Three kinds of measurement experiments were designed: γ-ray nondestructive method for the relative yield of 88Kr and 99Mo, gas-solid separation method for 85Krm, 87Kr and 88Kr and γ-ray nondestructive method for the relative yield of 85Krm, 87Kr and 88Kr. After the target irradiation and cooling, the fission products were measured by the above-mentioned methods. The efficiency of the three kinds of experimental samples was calibrated by the equivalent efficiency curve method. The plan source of organic glass package was used to equate the efficiency calibration of quartz tube source, and the plan source of stainless steel package with the same thickness and material as the measuring source was used to equate the efficiency calibration of 50 mL gas source. By Monte Carlo simulation, the suitable equivalent position was selected, and the efficiency value was fine corrected (less than 0.8%). The uranium target was prepared in the same way of plutonium target. The relative yields of 85Krm, 87Kr and 88Kr of 235U fission induced by thermal neutron measured by gas-solid separation after irradiation are consistent with the recommended values of the evaluation database, which indicates that the release rates of 85Krm, 87Kr and 88Kr in the plutonium target are the same. After modified by the influence of non-primary neutron field and non-primary isotope, the fission yields of 85Krm, 87Kr and 88Kr were obtained based on the measured relative yield with reference product 99Mo and the yield of 99Mo given by ENDF/BⅧ.0 evaluation database. The measured yields are (0.559±0.020)%, (0.992±0.034)% and (1.264±0.037)%, respectively, which are consistent with the evaluation value of the database and the uncertainty is significantly reduced compared with other literature value. In this paper, the retrieval and deduction methods of γ-ray energy peak interference ratio in measurement are universal, but the uncertainty of theoretical yield may be added. The experimental method in this paper can also provide reference for the measurement of fission product yield at different neutron energy points.

This article explored the changes and significance of the blood vessel diameter and blood flow before and after the maturation of the autogenous arteriovenous fistulas (AVF) in the forearm of dialysis patients. A total of 109 end-stage renal disease dialysis patients receiving forearm AVF angioplasty were selected as the research objects. According to whether the fistula was mature within 8 weeks after operation, they were divided into mature group (n=68) and immature group (n = 41). The clinical data of the two groups were compared. The internal diameter and blood flow of the cephalic vein and radial artery before and 8 weeks after the operation, and the data were analyzed and processed. The results showed that the internal diameter and blood flow of the cephalic vein and radial artery in the two groups were higher than that before the operation at 8 weeks after operation, and the mature group was higher than that of the immature group (P<0.05); multivariate logistic regression analysis showed that the cephalic vein and radial Arterial vessel diameter and blood flow are still related to fistula maturity (P<0.05). The area under the curve (AUC) of the combined assessment of cephalic vein and radial vein vessel diameter and blood flow for fistula maturity is greater than the individual parameters. The evaluation value is the highest; the maturity rate of patients with high level of cephalic vein and radial artery diameter and blood flow is higher than that of low level (P<0.05). It can be seen that the internal diameter and blood flow of the cephalic vein and radial artery after the mature AVF of the forearm are significantly increased. The use of ultrasound to detect the changes of blood vessels before and after AVF angioplasty can be used as a standard for evaluating the maturity of internal fistulas and provide a reference for clinical selection of puncture dialysis timing. [ABSTRACT FROM AUTHOR]

Objective To observe the influence of gallic acid on Toll-like receptor 4/nuclear factor-κB (TLR4/NF-κB) pathway in the RAW264.7 macrophages stimulated by lipopolysaccharide (LPS). Methods RAW264.7 macrophages were divided into the following groups: control group, LPS group, LPS combined with gallic acid group, LPS combined with pyrrolidine dithiocarbamate (PDTC) group and LPS combined with dexamethasone (DM) group. RAW264.7 cells were cultured for 24 hours after corresponding treatments. The levels of tumor necrosis factor α (TNF-α), interleukin-1 (IL-1) and IL-6 were detected by ELISA. The levels of TLR4 and NF-κB mRNAs were tested by real-time PCR. The levels of p-IκBα, p65, p-p65 and TLR4 proteins were examined by Western blotting. Results The expression levels of TNF-α, IL-1 and IL-6 were up-regulated in the RAW264.7 macrophages after stimulated by LPS. Gallic acid could reduce the elevated expression levels of TNF-α, IL-1 and IL-6 induced by LPS. The expression of TLR4 significantly increased after stimulated by LPS and NF-κB was activated. Gallic acid could reverse the above changes and prevent the activation of NF-κB. Conclusion Gallic acid could inhibit LPS-induced inflammatory response in RAW264.7 macrophages via TLR4/NF-κB pathway.

Objective: To study the anti-inflammatory mechanism of geniposide and observe the effect of geniposide on the expression of Toll-like receptor 4 (TLR4), the activity of NF-κB, and the release of pro-inflammatory cytokines- TNF-α, IL-1, and IL-6-in the RAW264.7 macrophages treated with lipopolysaccharide (LPS)., Methods: There were three experimental groups, including the control group, LPS group and LPS combined with geniposide group in this study. RAW264.7 macrophage cells were treated with LPS to induce cellular inflammation. Cell proliferation was measured by CCK-8. The concentrations of TNF-α, IL-1, and IL-6 in cell culture media were measured by ELISA. mRNA levels of TLR4 and P65 were examined by real-time PCR. The protein levels of p-IκB, P65, p-P65 and TLR4 were detected by Western blotting., Results: Geniposide had no effect on cell proliferation. However, geniposide down-regulated the expression of TNF-α, IL-1, and IL-6, and also inhibited the expression of TLR4 and the activity of NF-κB., Conclusion: Geniposide exerts its anti-inflammatory effect through inhibiting the activity of NF-κB in the TLR4-NF-κB pathway in macrophages.