期刊:
BMC Medical Informatics and Decision Making,2022年22(1):1-11 ISSN:1472-6947
通讯作者:
Yang, J.;Ni, Q.;Wan, Y.
作者机构:
[Zhang, Xiapeng; Zhou, Lifang; Yang, Jinghua; Wan, Yaping; Wang, Jin] Univ South China, Sch Comp Sci, Hengyang, Peoples R China.;[Wan, Yaping] Hunan Prov Base Sci & Technol Innovat Cooperat, Hengyang, Peoples R China.;[Ni, Qianxi] Hunan Canc Hosp, Changsha, Peoples R China.;[Yang, Jinghua; Ni, Qianxi] Univ South China, Sch Nucl Sci & Technol, Hengyang, Peoples R China.;[Zuo, Jianhong] South China Univ, Affiliated Hosp 3, Hengyang, Peoples R China.
通讯机构:
[Jinghua Yang; Yaping Wan] S;[Qianxi Ni] H;School of Computer Science, University of South China, Hengyang, China<&wdkj&>School of Nuclear Science and Technology, University of South China, Hengyang, China<&wdkj&>School of Computer Science, University of South China, Hengyang, China<&wdkj&>Hunan Provincial Base for Scientific and Technological Innovation Cooperation, Hengyang, China<&wdkj&>Hunan Cancer Hospital, Changsha, China<&wdkj&>School of Nuclear Science and Technology, University of South China, Hengyang, China
摘要:
Causal inference is a crucial element within medical decision-making. There have been many methods for investigating potential causal relationships between disease and treatment options developed in recent years, which can be categorized into two main types: observational studies and experimental studies. However, due to the nature of experimental studies, financial resources, human resources, and patients' ethical considerations, researchers cannot fully control the exposure of the research participants. Furthermore, most existing observational research designs are limited to determining causal relationships and cannot handle observational data, let alone determine the dosages needed for medical research. This paper presents a new experimental strategy called quasi-intervention for quantifying the causal effect between disease and treatment options in observed data by using a causal inference method, which converts the potential effect of different treatment options on disease into computing differences in the conditional probability. We evaluated the accuracy of the quasi-intervention by quantifying the impact of adjusting Chinese patients’ neutrophil-to-lymphocyte ratio (NLR) on their overall survival (OS) (169 lung cancer patients and 79 controls).The results agree with the literature in this study, consisting of nine papers on cohort studies on the NLR and the prognosis of lung cancer patients, proving that our method is correct. Taken together, the results imply that quasi-intervention is a promising method for quantifying the causal effect between disease and treatment options without clinical trials, and it could improve confidence about treatment options' efficacy and safety.
通讯机构:
[Hai Wang] S;[Jian Zheng] N;School of Nuclear Science and Technology, University of South China, Hengyang, 421001, China<&wdkj&>National Institute of Radiological Sciences, National Institutes for Quantum Science and Technology, 491 Anagawa, Inage, Chiba, 263-8555, Japan<&wdkj&>National Institute of Radiological Sciences, National Institutes for Quantum Science and Technology, 491 Anagawa, Inage, Chiba, 263-8555, Japan
摘要:
The source and vertical distribution of (137)Cs,(239+240)Pu and (241)Am activity concentrations in a soil core from Hunan Province, China were investigated. The maximum (137)Cs and (239+240)Pu activity concentrations were 15.45±0.76 mBq/g and 0.819±0.066 mBq/g, respectively. While the maximum (241)Am activity concentration in samples obtained from the core was 0.341±0.019 mBq/g. The (240)Pu/(239)Pu atom ratio and the (137)Cs/(239+240)Pu activity ratio were 0.183±0.011 and 19.5±1.8, respectively, and both were consistent with the characteristic value of global fallout. The integrated (241)Am/(239+240)Pu activity ratio for global fallout was also re-estimated. The measured (241)Am/(239+240)Pu activity ratio (average 0.43±0.07) in the samples was very close to the estimated value (0.45), which suggested their (241)Am also came from the global fallout. Regarding the vertical distribution of (137)Cs, (239+240)Pu and (241)Am in these red soil samples, all these radionuclides had higher concentrations in upper layers of several centimeters of soil while they had slightly lower concentrations in lower soil layers down to 30cm. Vertical distributions of (137)Cs/(239+240)Pu and (241)Am/(239+240)Pu activity ratios indicated the migration velocity was Am≈Pu>Cs. The intrinsic chemical properties of the radionuclides as well as soil type and properties (acidic, nutrient-deficient and low in organic matter and cation exchange capacity) might be reasons for the differences in their migration behaviors.
通讯机构:
[Anguo Peng] S;School of Nuclear Science and Technology, University of South China, Hengyang 421001, China
关键词:
Sediment;Radionuclide;Heavy metal;Contamination assessment;Nansha Sea area
摘要:
Activity concentrations of radionuclides (238U, 226Ra, 232Th, and 40K) in the sediments of eight sampling stations and heavy metal concentrations (Cr, Co, Ni, Cu, Zn, As, Cd, and Pb) in the sediments of two long cores from Nansha Sea area were obtained by high-purity germanium spectroscopy and inductively coupled plasma atomic emission spectrometry. In a correlation analysis between the radionuclides and heavy metals, 232Th was positively correlated with As and Pb. 238U demonstrated a significant positive correlation with Co, Ni, Cu, Zn, and Cd. 40K was positively correlated with Co, Ni, and Cu. The geo-accumulation index, pollution load index, potential ecological risk index, and multivariate statistical techniques were used to evaluate the pollution degree and possible sources of heavy metals in the sediments. An ecological risk assessment suggested that Cr, Co, Ni, Cu, Zn, Cd, and Pb were primarily derived from natural processes, while the source of As may be related to natural processes and human activities.
作者机构:
[姚鑫森] Radiotherapy Center, Chenzhou First People's Hospital, Chenzhou 423000, China;[巩贯忠; 尹勇] Department of Radiation Physics, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan 250117, China;[任建新] School of Physics and Technology, Wuhan University, Wuhan 430072, China;[左国平] School of Nuclear Science and Technology, University of South China, Hengyang 421001, China
通讯机构:
[Yong, Y.] D;Department of Radiation Physics, China
摘要:
To understand the physical and chemical characteristics, particle size distribution and sources of size-separated aerosols in Lhasa, which is located on the Tibetan Plateau (TP), six sizes of aerosol samples were collected in Lhasa in 2014. Ca(2+), NH4(+), NO3(-), SO4(2-) and Cl(-) were the dominant ions. The ratio of cation equivalents (CE) to anion equivalents (AE) for each particle size segment indicated that the atmospheric aerosols in Lhasa were alkaline. SO4(2-) and NO3(-) could be neutralized by Ca(2+), but could not be neutralized by NH4(+), according to the [NH4(+)]/[NO3(-)+SO4(2-)] and [Ca(2+)]/[NO3(-)+SO4(2-)] ratios. Mobile sources were dominant in PM0.95-1.5, PM1.5-3 and PM3-7.2, while stationary sources were dominant in the other three size fractions according to the [NO3(-)]/[SO4(2-)] ratios. The particle size distribution of all water-soluble ions during monsoon and non-monsoon periods was characterized by a bimodal distribution due to the different sources and formation mechanisms, and it was revealed that different ions had different sources in different seasons and different particle size segments by combining particle size distribution with correlation analysis. Source analysis of aerosols in Lhasa was performed using the Principal component analysis (PCA) for the first time, which revealed that combustion sources, motor vehicle exhaust, photochemical reaction sources and various types of dust were the main sources of Lhasa aerosols. Furthermore, Lhasa's air quality was also affected by long-distance transmission, expressed as pollutants from South Asia and West Asia, which were transmitted to Lhasa according to backward trajectory analysis.
关键词:
(239+240)Pu;(240)Pu/(239)Pu atom ratio;Fukushima accident;ICP-MS;Seawater
摘要:
The marine environment is complex, and it is desirable to have measurements for seawater samples collected at the early stage after the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident to determine the impact of Fukushima-derived radionuclides on this environment. Here Pu isotopes in seawater collected 33-163 km from the FDNPP site at the very early stage after the accident were determined (May 2011, within two months after the accident). The distribution and temporal variation of Pu-239 and Pu-240 were studied. The results indicated that both (239+24) PU activity concentrations (from 0.81 +/- 0.16 to 11.18 +/- 1.28 mBq/m(3)) and Pu-240/Pu-239 atom ratios (from 0.216 +/- 0.032 to 0.308 +/- 0.036) in these seawater samples were within the corresponding background ranges before the accident, and this suggested that Fukushima-derived Pu isotopes, if any, were in too limited amount to be distinguished from the background level in the seawater. The analysis of Pu isotopic composition indicated that the major sources of Pu in the seawater after the accident were still global fallout and the Pacific Proving Ground close-in fallout. The contribution analysis showed that the contributions of the Pacific Proving Ground close-in fallout in the water column of the study area ranged from 26% to 77% with the average being 48%. (C) 2018 Elsevier Ltd. All rights reserved.
摘要:
Radon, known to be a human carcinogen, is one of the most concerned radionuclides in uranium mining which need to be monitored and controlled. A large amount of radon is discharged to the atmosphere mainly through underground ventilation shafts for underground uranium mining. There are many studies on radon release of uranium mine, but the differences of the measured radon results are very big. In this paper, a typical underground uranium mine in China is chosen as a case study. This study finds that distribution of radon concentration and airflow speed inside the ventilation shaft are extremely uneven, but the distributions are respectively stable and regular for a fixed cross-section at the wellhead depth of 0-1m. There is also a stable numerical relationship between the radon release rate and the product of radon concentration and airflow speed at the center for any cross-section in the shaft. Based on this regulation, a multipoint interpolation-integration method and a one-point method for calculating radon release from underground ventilation shaft are proposed in this paper. The results show that the difference between these two methods is 2-10%, the one-point method is more suitable and convenient to be applied for the long-term monitoring radon release rate from uranium mine ventilation. The research results in this paper can be applied in the estimation of radon release rate for other underground uranium ventilation shafts.
关键词:
Esophageal cancer radiotherapy;Deformable image registration;Dose-volume parameters;Heart;Left ventricular myocardium
摘要:
The deformable image registration (DIR) technique has the potential to realize the dose accumulation during radiotherapy. This study will analyze the feasibility of evaluating dose-volume parameters for the heart and left ventricular myocardium (LVM) by applying DIR. The electrocardiograph-gated four-dimensional CT (ECG-gated 4DCT) data of 21 patients were analyzed retrospectively. The heart and LVM were contoured on 20 phases of 4DCT (0%, 5%,…,95%). The heart and LVM in the minimum volume/dice similarity coefficient (DSC) phase (Volume min/DSC min) were deformed to the maximum volume/DSC phase (Volume max/ DSC max), which used the intensity-based free-form DIR algorithm of MIM software. The dose was deformed according to the deformation vector. The variations in volume, mean dose (Dmean), V20, V30 and V40 for the heart and LVM before and after DIR were compared, and the reference phase was the Volume max/DSC max phase. For the heart, the difference between the pre- and post-registration Volume min and Volume max were reduced from 13.87 to 1.72%; the DSC was increased from 0.899 to 0.950 between the pre- and post-registration DSC min phase relative to the DSC max phase. The post-registration Dmean, V20, V30 and V40 of the heart were statistically significant compared to those in the Volume max/DSC max phase (p < 0.05). For the LVM, the difference between the pre- and post-registration Volume min and Volume max were only reduced from 18.77 to 17.38%; the DSC reached only 0.733 in the post-registration DSC min phase relative to the DSC max phase. The pre- and post-registration volume, Dmean, V20, V30 and V40 of the LVM were all statistically significant compared to those in the Volume max/DSC max phase (p < 0.05). There was no significant relationship between the variation in dose-volume parameters and the variation in the volume and morphology for the heart; however, the inconsistency of the variation in the volume and morphology for the LVM was a major factor that led to uncertainty in the dose-volume evaluation. In addition, the individualized local deformation registration technology should be applied in dose accumulation for the heart and LVM.
摘要:
In order to assess the impact of the Fukushima derived Pu isotopes on seawater, a new analytical method to rapidly determine Pu isotopes in seawater by SF-ICP-MS including Fe(OH)(2) primary co-precipitation, CaF2/LaF3 secondary co-precipitation and TEVA+UTEVA+DGA extraction chromatographic separation was established. High concentration efficiency (similar to 100%) and high U decontamination factor (similar to 10(7)) were achieved. The plutonium chemical recoveries were 74-88% with the mean of 83 +/- 5%. The precisions for both Pu-240/Pu-239 atom ratios and Pu239+240 activity concentrations were less than 5% when 15 L of seawater samples with the typical Pu239+240 activity of the Northwest Pacific were measured. It just needs 12 hours to determine plutonium using this new method. The limit of detection (LOD) for Pu-239 and Pu-240 were both 0.08 fg/mL, corresponding to 0.01 mBq/m(3) for Pu-239 and 0.05 mBq/m3 for Pu-240 when a 15 L volume of seawater was measured. This method was applied to determine the seawater samples collected 446-1316 km off the FDNPP accident site in the Northwest Pacific in July of 2013. The obtained Pu239+240 activity concentrations of 1.21-2.19 mBq/m(3) and the Pu-240/Pu-239 atom ratios of 0.198-0.322 suggested that there was no significant Pu contamination from the accident to the Northwest Pacific.
摘要:
This research investigated the relationship between lymphocytes apoptosis, hypothalamic-pituitary adrenal (HPA) axis and NF-kappa B in AICI(3)-treated rats. Eighty Wistar rats were orally exposed to 0 (control group, CG), 0.4 mg/mL (low-dose group, LG), 0.8 mg/mL (mid-dose group, MG) and 1.6 mg/mL (high dose group, HG) AlCl3 for 90 days, respectively. A variety of measurements were taken including lymphocyte apoptosis index, serum corticotropin-releasing hormone (CRH), adrenocorticotrophic hormone (ACTH) and glucocorticoids (GCs) contents, GC receptors (GCR) and NF-kappa B mRNA and nuclear protein expressions, caspase 3 and 9 mRNA expressions and activities. The results showed that in the AlCl3-treated rats serum CRH, ACTH and GCs contents, lymphocyte GC receptors (GCR) mRNA and nuclear protein expressions, caspase 3 and 9 mRNA expressions and activities increased, while Bcl-2/Bax ratio and NF-kappa B mRNA and nuclear protein expressions decreased compared with the CG. Furthermore GCR and NF-kappa B nuclear protein expressions were negatively correlated. And NF-kappa B mRNA expression was positively correlated with that of Bcl-2, but negatively correlated with that of Bax in AlCl3-treated rats. These findings indicated that AlCl3 activated HPA axis, then induced splenic lymphocytes apoptosis through NF-kappa B inhibition. (C) 2016 Elsevier Ireland Ltd. All rights reserved.
作者机构:
[Luo, W.; Zhu, Z. C.; Song, Y. M.] Univ South China, Sch Nucl Sci & Technol, Hengyang 421001, Peoples R China.;[Yu, T. P.; Zhuo, H. B.; Ma, Y. Y.] Natl Univ Def Technol, Coll Sci, Changsha 410073, Hunan, Peoples R China.;[Chen, M.] Shanghai Jiao Tong Univ, Dept Phys & Astron, Minist Educ, Key Lab Laser Plasmas, Shanghai 200240, Peoples R China.
通讯机构:
[Zhu, Z. C.] U;Univ South China, Sch Nucl Sci & Technol, Hengyang 421001, Peoples R China.
关键词:
Attosecond pulses;Backscattering;Hard x rays;High harmonic generation;Synchrotron radiation;Thomson scattering
摘要:
Generation of attosecond x-ray pulse attracts more and more attention within the advanced light source user community due to its potentially wide applications. Here we propose an all-optical scheme to generate bright, attosecond hard x-ray pulse trains by Thomson backscattering of similarly structured electron beams produced in a vacuum channel by a tightly focused laser pulse. Design parameters for a proof-of-concept experiment are presented and demonstrated by using a particle-in-cell code and a four-dimensional laser-Compton scattering simulation code to model both the laser-based electron acceleration and Thomson scattering processes. Trains of 200 attosecond duration hard x-ray pulses holding stable longitudinal spacing with photon energies approaching 50 keV and maximum achievable peak brightness up to 1020 photons/s/mm2/mrad2/0.1%BW for each micro-bunch are observed. The suggested physical scheme for attosecond x-ray pulse trains generation may directly access the fastest time scales relevant to electron dynamics in atoms, molecules and materials.
摘要:
This paper presents a process in which a radon monitor based on the electrostatic collection method is used to measure the 222Rn and 220Rn exhalation rates simultaneously and continuously employing a ventilation-type accumulation chamber. Generally, the radon exhalation rate can be measured by accumulation technique, but cannot be measured continuously. The advantage of this method using a ventilation-type accumulation chamber is that the radon exhalation rates can be measured continuously. Even though the environmental air is drawn into the chamber, the low atmospheric values of radon and thoron do not influence the measurement accuracy. The 222Rn and 220Rn exhalation rates error from the environmental air is less than 5% in this experiment.