Monitoring and evaluation of radioactivity levels in water sources in Beijing, China, 2012—2021 / 中国辐射卫生

Objective To investigate and evaluate the changes in total α and total β radioactivity levels in drinking water in Beijing, China, 2012—2021. Methods The test results of total α and total β radioactivity levels at 14 monitoring sites from 9 groundwater sources and 5 surface water sources in Beijing, 2012—2021 were collected. The radioactivity levels in the two types of water sources were compared. Statistical charts were used to show the monitoring situation at sampling sites in different regions during different periods, and related issues were explored. Results The total α and total β activity concentrations measured at monitoring sites from some water sources in Beijing, 2012—2021, were less than the total α and total β guideline values specified in the Standards for Drinking Water Quality (GB 5749—2006) (total α: 0.5 Bq/L, total β: 1.0 Bq/L). The mean total α activity concentration in the groundwater was significantly higher than that in the surface water. The total α and total β radioactivity levels in the reservoir D in the surface water were slightly higher than those in the other surface water. Conclusion In the past decade from 2012 to 2021, the total α and total β radioactivity levels in some water sources in Beijing were generally in a good condition and fluctuated within the range of environmental background values, without significant changes on the whole.

Determination of gross α and gross β radioactivity in IAEA-2020-intercomparison samples / 中华放射医学与防护杂志

Objective:To summarize the practices in measuring the gross α and gross β radioactivity in IAEA-2020-intercomparison samples, which could be expected to be beneficial to the similar analysis and research.Methods:With 241Am, Th, 90Sr/ 90Y, 40K and 137Cs solution as standard materials, the gross α and gross β radioactivity in water and aerosol samples were determined using thin source method. With 241Am, 40K powder as standard materials, the gross α and gross β radioactivity in water and fish samples were measured using thick source method combined with evaporation. Results:The result showed that the relative deviation and Z-score by using thin source method were 4.12%-31.6% and 0.14-1.71, respectively, and those from thick source combined with evaporation were 2.63%-32.5% and 0.11-0.93, respectively, with the acceptance rate being 100%. Conclusions:Generally, standard material shall be selected in the same types of radionuclides and energies as in samples. The thin source method is appropriate for emergency monitoring in the event of an accident. The thick source combined with evaporation should be perfered to the environmental monitoring or the analysis of unknown samples in laboratory. And then an intercomparison should be done with thin source method based on the radioactivity in samples. This work can provide a technical reference for similar measurements.

Monitoring and analysis of gross radioactivity of centralized drinking-water of township in Beijing / 中国辐射卫生

Objective To investigate the distribution of gross α and gross β levels of centralized drinking-water of township in Beijing from 2018 to 2019, so as to carry out better monitoring and evaluating the radioactivity in water. Methods A total of 215 underground drinking water samples were collected from 12 districts of Beijing, then monitored and evaluated according to the Determination of gross alpha activity in water-thick source method EJ/T 1075—1998 and Determination of gross beta activity in water-evaporation method EJ/T 900—1994. Results The gross α level of centralized drinking water of township in Beijing was 0.050 (0.052) Bq/L, ranging from 0.001 to 0.210 Bq/L, and the gross β level was 0.048 (0.038) Bq/L, ranging from 0.002 to 0.261 Bq/L from 2018 to 2019. Gross α and gross β levels of all samples did not exceed the guidance value recommended by standards for drinking water quality. There was no significant difference in the distribution of gross α and gross β levels of samples of all districts from 2018 to 2019(P > 0.05), there were significant differences in the distribution of gross α and gross β levels of samples from different district in the same period (P < 0.05). And the levels of Miyun, Huairou and Shunyi in Chaobai River system were higher than other districts. Conclusion The distribution of radioactive background of centralized drinking-water of township in Beijing was mastered, which was in the normal range.

Effects of HLA disparity of two umbilical cord blood units on human engraftment in SCID mice / 中华血液学杂志

<p><b>OBJECTIVE</b>To evaluate the feasibility and characteristics of human engraftment in HLA disparate cord blood transplantation.</p><p><b>METHODS</b>Two human HLA-haploidentical or HLA-mismatched cord blood units were transplanted into sublethally irradiated severe combined immunodeficiency (SCID) mice. The characteristics of engraftment, hematopoietic and immunological reconstitution between the two groups were compared.</p><p><b>RESULTS</b>Two mixed cord blood units can engraft in SCID mice with donor-recipient chimerism and reconstitute hematopoiesis and immunological functions. No unfavorable factors had been observed. Only one of the two cord blood units which had higher colony forming ability in vitro could engraft in most SCID mice as shown by HLA-DQB(1) gene detection. Two HLA-haploidentical cord blood units were simultaneously engrafted in 3 SCID mice.</p><p><b>CONCLUSION</b>Double HLA-haploidentical or HLA-mismatched cord blood can engraft in SCID mice and reconstitute hematopoietic and immunological functions. HLA disparity has no significant effect on survival and engrafting rate. However, in less HLA disparity group, two cord blood units were prone to engraft simultaneously.</p>

Vascular endothelial growth factor promotes hematopoietic differentiation from mouse embryonic stem cells / 中国病理生理杂志

AIM: To study the effect of vascular endothelial growth factor(VEGF) on hematopoietic differentiation from mouse embryonic stem cells(ESC) in vitro.METHODS: ES-D3 was allowed to grow on mouse fetal fibroblast feeder layer,and then was developed into embryoid bodies(EB).EB cells were transferred into medium supplemented with different concentration of VEGF and VEGF+SCF for 1 week.Six groups,including.VEGF 5 ?g/L,VEGF 10 ?g/L,VEGF 20 ?g/L, VEGF 5 ?g/L+SCF,VEGF 10 ?g/L+SCF and VEGF 20 ?g/L+SCF,were designed.The group of spontaneous differentiation without cytokine(s) was used as control.Hematopoietic transcription factor GATA-2 and early hematopoietic differentiation genes(c-kit and ?-H1) were detected by RT-PCR.The content of CD34~+ cells in each group were measured by flow cytometry.The cells derived from ESC were incubated in semisolid methycellulose cultures.The numbers of total colony-forming units in culture(CFU-C) were counted by reverse microscope.RESULTS: ES-D3 grew and formed EB at day 4.VEGF had a stimulatory effect as a single factor on the expression of genes associated with early hematopoietic differentiation(GATA-2,c-kit and ?-H1),the generation of CD34~+ cells and CFU-C in EB.The effects of VEGF+SCF were the most potent in the experimental groups according to the percent of CD34~+ cells and the numbers of hematopoietic colonies.The most highest inducing efficacy was achieved in VEGF 20 ?g/L or VEGF 10 ?g/L combined with SCF.CONCLUSION: VEGF promotes the differentiation of ESC into hematopoietic cells in vitro.The strongest effect was achieved when VEGF was combined with SCF.

The law and ethics of blood in the umbilical cord / 中国医学伦理学

The rapid dlevelopment of life science,specially the coning technique,has made science and society,ethics and law become very complicated life science involved the stem cell of blood in the umbilical cord how to be transplanted and gene research.These problems have already ouched upon a series of law cond ethics.The paper stated the lawful and ethical problems about the blood in the umbilical cord from its belongs,management and privator rights.