Objective To investigate the separation efficiency of three physical separation methods for gaseous ¹⁴C, namely membrane separation, adsorption separation, and low-temperature separation, to screen for the optimal separation method, and to provide a reference for the separation and enrichment of ¹⁴CO₂ in online monitoring of ¹⁴C. Methods The experimental plan was designed, and three devices were constructed for separation and purification experiments. The purity, recovery rate, and separation time of CO₂ separated by the three methods were analyzed. Results All the three methods achieved the separation of CO₂. Under certain conditions, 20 mL of sample gas was obtained. The separation time of membrane separation method was 0.5 hour, CO₂ gas with a sample purity of 0.0486%-0.0488%VOL was obtained, and the recovery rate was only 2.5%−12.7%. The separation time of MOF material adsorption separation method was 24−30 hours, CO₂ gas with a sample purity of 20.2%−47.5%VOL was obtained, and the recovery rate was 57.3%−63.2%. The separation time of low-temperature separation method was 3 hours, CO₂ gas with a sample purity of 96.0%−99.8%VOL was obtained, and the recovery rate was 81.5%−92.5%. Conclusion The purity and recovery rate of CO₂ with low-temperature separation method were higher compared to membrane separation method and MOF material adsorption separation method. The separation time of low-temperature separation method was moderate. The low-temperature separation method can provide a reference for the enrichment technology of ¹⁴C in the rapid measurement of gaseous ¹⁴C effluent.

Objective To investigate the natural penetrating radiation levels along the Qinghai-Tibet Railway, and to preliminarily evaluate the doses received by the railway employees and passengers. Methods Natural penetrating radiation was measured at 15 typical locations with different altitudes along the railway and in the carriages of a train from Lhasa to Xining using high-pressure ionization chamber RSS131, sodium iodide radiation dose rate meter MARS1561, and neutron ambient dose equivalent rate meter LB6411. Results The levels of terrestrial gamma radiation, cosmic ray ionization components, and neutron radiation were 21.5-246.6 nGy/h, 79.8-225.5 nGy/h, and 24.5-101 nSv/h, respectively. The effective dose of natural penetrating radiation received by passengers and crew on a train from Lhasa to Xining was 4.82 μSv. Conclusion Comparison with the empirical formula and verification of method reliability confirm the accuracy of the measurement. Our results provide a primary understanding of the radiation levels along the Qinghai-Tibet Railway and the radiation doses received by passengers, which can be used as a basis for the regulatory authorities.

Objective To provide a reference for avoiding the harm to critical target organs following considerable inhalation exposure to the transuranium element americium (Am) as well as post-accident decorporation or other radiation protection measures. Methods We established calculation programs based on the generic criteria for internal radiation emergency preparedness and response in the IAEA Safety Guide No.GSG-2 and current new ICRP biokinetic models and parameters, taking an inhalation of ²⁴¹Am (activity mean aerodynamic diameter of 5 μm, σ = 2.5) by an adult worker as an example; and determined that the critical target organs were the lung AI region, red bone marrow, and the main source organs leading to acute doses to the critical target organs were the lung AI region, blood, and trabecular bone surface. Results The retention fractions in the main source organs over time after ²⁴¹Am inhalation were calculated. Conclusion After being absorbed into blood, Am moves quickly to other parts, and Am of different absorption types shows similar early changes in retention fractions in blood: the retention fractions of Am of S, M, and F types in blood peak around 0.03 d, and then halve around 1.7 d. Inhaled Am shows different changes over time in retention fractions in the lung AI region and trabecular bone surface in the early stage: the retention fractions of S- and M-type Am in the lung AI region change little with time, while F-type Am transfers quickly from the lung to blood; In trabecular bone surface, S-type Am increases quickly in the first 7 d, M-type Am gradually increases mainly in the first 2 weeks, and F-type Am increases quickly in the first 2 d.

Vaccine cooperation is an important means to deal with global infectious diseases. However, the cooperation cannot be achieved overnight. Ethical dilemma is one of the obstacles that hinders vaccine cooperation. Reviewing the history, the most successful vaccine collaboration to date has been the global smallpox eradication program. In the process of eradicating smallpox, there were also many ethical dilemmas, including the international pattern of the US-Soviet hegemony, which impacted the mutual help between countries, the ethical disputes of the vaccine itself hindering solidarity and cooperation among actors, and the vaccine coercion adopted to overcome vaccine hesitancy undermining the principle of proportionality among the freedom, equality and efficacy. The ethical dilemmas of vaccine cooperation were resolved by shaping professional and scientific consensus among medical professional groups, reaching consensus on cooperation between leading countries and developing countries, and integrating local culture to improve vaccination methods. Finally, in 1980, the world successfully eradicated smallpox. The case of smallpox eradication provides us lessons for vaccine cooperation against COVID-19 and the construction of a community of common health for mankind today.

Portal hypertension is a pathological elevation of portal pressure gradient(PPG),often leading to severe complications.Interventional shunting such as transjugular intrahepatic portosystemic shunt(TIPS)has gradually become an important means of treatment,but the postoperative hemodynamic changes are uncertain,therefore,individualized treatment scheme with precision shunting is needed.The purpose of precision shunting is to balance the amount of shunting blood with the amount of blood perfusion in the liver tissue,which can minimize the incidence of complications while relieving symptoms.The determination of hemodynamic goals after interventional shunting is influenced by various factors,and the procedural differences and individual variances should be taken into consideration when making reasonable postoperative hemodynamic targets(optimal PPG).The preliminary results of clinical practice of precision shunting indicates that accurate measurement of preoperative portal pressure and effective monitoring of postoperative hemodynamic status should be emphasized.Future studies should further improve the interventional shunting technique to achieve a more individualized precision treatment.

Anti-glomerular basement membrane (GBM) nephritis and anti-neutrophil cytoplasmic antibody (ANCA) -associated vasculitis are both autoimmune diseases that can involve multiple systems throughout the body, and both can cause crescent glomerulonephritis. At present, cases of such "double-positive" antibodies have been reported at home and abroad , but the cases of acute progressive glomerulonephritis (RPGN) with IgA nephropathy that are both positive for GBM and ANCA are relatively rare. This case was a middle-aged female patient, whose clinical manifestations were consistent with rapidly progressive glomerulonephritis, positive for anti-GBM antibodies and anti-myeloperoxidase. After renal puncture biopsy, she was diagnosed as anti-GBM nephritis complicated with ANCA associated vasculitis and IgA nephropathy.After treatment with plasma exchange, hemodialysis, glucocorticoids, cyclophosphamide, etc., the condition improved and the patient was discharged. But the patient did not follow the doctor's instructions to take medication and continue hemodialysis treatment after discharge, and the condition worsened, ultimately leading to death.

Objective To develop a simplified phantom for the calibration of whole-body counters. Methods A simplified phantom design method for the calibration of whole-body counters was established based on the process and method of calibrating whole-body counters. By using the established method and Monte Carlo method, a simplified phantom including the total body, thyroid, lungs, and gastrointestinal tract was designed to calibrate the ORTEC-Stand FAST II whole-body counter. The simplified phantom was compared with the BOMAB phantom through experimental measurements. Results Within the range of 50 keV to 2 MeV, for rays of the same energy in the same organ of the simplified phantom and BOMAB phantom, the simulated data of detection efficiency by whole-body counting showed an error within 5%, and the experimental measurements showed an error within 10%. Conclusion We developed a simplified phantom for the calibration of the whole-body counter, demonstrating the feasibility of using the simplified phantom instead of a physical body phantom for whole-body counter calibration, which can greatly facilitate whole-body counter calibration for internal radiation monitoring.

The concept of "virus sovereignty" proposed by Indonesia in 2007 challenges the international tradition of virus sharing. In the context of the global outbreak of coronavirus disease 2019, the issue of virus sharing has become an important topic in the reform of the global health governance mechanisms. Virus sharing is an important guarantee of dealing with major global infectious diseases. However, the emergence of the concept of "virus sovereignty" shows that there are defects in the operation of virus sharing mechanism in the international community. The "virus sovereignty" problem is an ethical issue essentially, involving asymmetric interests hindering unity and cooperation, intellectual property rights expansion challenging the principle of solidarity, and excessive self-defense amplifying utility risks. "Community of common health for mankind" provides a constructive and feasible option to solve the dilemma of "virus sovereignty".

Objective To establish a method for measurement of ²³⁹Pu in fecal samples based on inductively coupled plasma-mass spectrometry (ICP-MS), and to provide a novel method for assessing the internal exposure of workers. Methods Fecal samples were collected from workers and labeled. The samples were pretreated with carbonization ashing and microwave digestion devices, purified on TEVA resin, and measured using ICP-MS. Results The detection limit of ²³⁹Pu in fecal samples based on ICP-MS was 1.91 × 10⁻⁴ Bq. Conclusion In the routine monitoring of class S substances characterized by a 5 μm aerodynamic diameter during 12 months, the committed effective dose corresponding to the detection limit is 0.17 mSv. This value meets the requirements of relevant national standards and ICP-MS can be used as a novel means for accurate evaluation of internal exposure for workers.

Primary ciliary dyskinesia (PCD) is a congenital, motile ciliopathy with pleiotropic symptoms. Although nearly 50 causative genes have been identified, they only account for approximately 70% of definitive PCD cases. Dynein axonemal heavy chain 10 (DNAH10) encodes a subunit of the inner arm dynein heavy chain in motile cilia and sperm flagella. Based on the common axoneme structure of motile cilia and sperm flagella, DNAH10 variants are likely to cause PCD. Using exome sequencing, we identified a novel DNAH10 homozygous variant (c.589C > T, p.R197W) in a patient with PCD from a consanguineous family. The patient manifested sinusitis, bronchiectasis, situs inversus, and asthenoteratozoospermia. Immunostaining analysis showed the absence of DNAH10 and DNALI1 in the respiratory cilia, and transmission electron microscopy revealed strikingly disordered axoneme 9+2 architecture and inner dynein arm defects in the respiratory cilia and sperm flagella. Subsequently, animal models of Dnah10-knockin mice harboring missense variants and Dnah10-knockout mice recapitulated the phenotypes of PCD, including chronic respiratory infection, male infertility, and hydrocephalus. To the best of our knowledge, this study is the first to report DNAH10 deficiency related to PCD in human and mouse models, which suggests that DNAH10 recessive mutation is causative of PCD.
Humans ; Male ; Animals ; Mice ; Semen/metabolism* ; Dyneins/metabolism* ; Cilia/metabolism* ; Mutation ; Ciliary Motility Disorders/genetics*