Fostering inclusive green growth in China: Identifying the impact of the regional integration strategy of Yangtze River Economic Belt.

Inclusive green growth has garnered significant attention from governments and international organizations worldwide. Utilizing data from 282 cities in China spanning from 2010 to 2020, this study employs the dual machine learning model and the chain mediated effect model to delve into the effects and internal mechanisms of the regional integration of Yangtze River Economic Belt on inclusive green growth. Our findings indicate that the regional integration of Yangtze River Economic Belt has a substantial influence on inclusive green growth, particularly in cities with a higher degree of marketization, non-industrial cities, and cities lacking natural resource advantages. Mechanistic analysis reveals that the regional integration of Yangtze River Economic Belt exerts its influence on inclusive green growth through three parallel development paths including enhancing urban innovation levels, fostering mass entrepreneurship, and promoting the advancement of digital financial inclusion. Furthermore, the chain mediated effect is supported. Additionally, the spatial spillover effect of target policy is observed. These findings offer empirical evidence regarding the impact of the regional integration of Yangtze River Economic Belt on inclusive green growth, and provide valuable insights for optimizing and enhancing inclusive green growth strategies in China and other emerging economies.

Combined Efficacy of Modified Yangxin Anshen Decoction and Western Medicine Treatment in Elderly Patients with Schizophrenia and Sleep Disorders.

Objective: To explore the combined efficacy of modified Yangxin Anshen decoction and Western medicine treatment in elderly patients with schizophrenia and sleep disorders. Methods: A total of 144 elderly patients with schizophrenia and sleep disorders in Wuhan Wudong Hospital were enrolled as participants in this study from April 2021 to April 2022. The participants were randomly and equally divided into a control group (receiving conventional Western medicine treatment) and two study groups: study group 1 received modified Yangxin Anshen decoction, and study group 2 receive modified Yangxin Anshen decoction in addition to Western medicine treatment. TCM syndrome scores, sleep quality, polysomnography, serum levels of 5-HT, DA, and MT were compared between the two groups. Moreover, the efficacy and adverse reactions were recorded. Results: After four weeks of treatment, the efficacy of study group 2 was significantly better than that of the control group and Study Group 1 (P < .05). There was no statistically significant difference between the three groups in secondary and main symptoms before treatment (P >.05), while the secondary and main symptoms of study group 2 were significantly lower than those of the control group and study group 1 after four weeks of treatment (P < .05). Before treatment, no statistically significant difference was found in sleep quality score between the three groups (P > .05), whereas the index of the study group 2 was evidently lower than that of the control group and study group 1 after four weeks of treatment (P < .05). Before treatment, there was no significant difference in terms of total recording time, total sleep time, sleep onset latency, sleep efficiency, and four stages (N1, N2, N3, and REM) between the three groups (P > .05). After four weeks of treatment, although no statistically significant difference was shown in total recording time between the three groups (P > .05), the total sleep time, sleep onset latency, sleep efficiency, and four stages (N1, N2, N3, and REM) of the study group 2 were significantly improved than those of the control group and the study group 1 (P < .05). Before treatment, there was no significant difference in serum levels of 5-HT, DA, and MT between the three groups (P > .05), while the three indexes were evidently lower than the control group and the study group 1 after four weeks of treatment (P < .05). During the treatment process, 1 case of mild dry mouth occurred in the study group who did not receive special treatment, and the incidence of adverse reactions was 1/48. In the control group, there were 3 cases of dry mouth, 1 case of constipation, 1 case of diarrhea, 1 case of decreased appetite, and 1 case of nausea, whose symptoms were not specially treated, with the incidence of adverse reactions of 7/48. Hence the incidence of adverse reactions in the study group was significantly lower than that in the control group (P < .05). Conclusion: Combined treatment with modified Yangxin Anshen decoction and Western medicine improved sleep quality in elderly patients with schizophrenia and sleep disorders, which is available for wide clinical application.

CK2B is a Prognostic Biomarker and a Potential Drug Target for Hepatocellular Carcinoma.

BACKGROUND: Although casein kinase II subunit beta (CK2B) was previously reported to be involved in human cancers, such as hepatocellular carcinoma (HCC), there has been no systematic assessment of CK2B in HCC. OBJECTIVE: To assess the potential function of CK2B as a prognostic biomarker and possible druggable target in HCC. METHODS: The Cancer Genome Atlas database was accessed to investigate the potential oncogenic and prognostic roles of CK2B in HCC. Diverse analytical methods were used to obtain a fuller understanding of CK2B, including CIBERSORT, The Tumor Immune Estimation Resource (TIMER), gene set enrichment analyses (GSEA), Kyoto Encyclopedia of Genes and Genomes (KEGG), and gene ontology (GO). Furthermore, the Comparative Toxicogenomic Database (CTD) was used to identify potential drugs to treat CK2B-overexpressing HCC. Patents for these drugs were reviewed using Patentscope® and Worldwide Espacenet®. RESULTS: Upregulated CK2B expression was markedly associated with more aggressive pathological features, including G3, G4 (vs. G1, G2), and T2, T3 (vs. T1). Kaplan-Meier survival curves indicated that patients with HCC with higher expression of CK2B had worse overall survival (P = 0.005), progression-free interval (P = 0.001), and disease-specific survival (P = 0.011). GO and KEGG analysis revealed that CK2B dysregulation affects mitotic chromosome condensation, protein stabilization and binding, regulation of signal transduction of p53 class mediator, and cancer-related pathways. GSEA identified six well-known pathways, including MAPK, WNT, Hedgehog, and TGFß signaling pathways. Finally, CTD identified six compounds that might represent targeted drugs to treat HCC with CK2B overexpression. A review of patents indicated these compounds showed promising anticancer results; however, whether CK2B interacts with these drugs and improves drug outcomes for patients with HCC was not confirmed. CONCLUSION: CK2B is a biomarker for HCC prognosis and could be a potential new drug target. Moreover, the association between infiltrating immune cells and CK2B in the HCC tumor microenvironment might provide a solid basis for further investigation and a potent strategy for immunotherapy of HCC.

Immunomodulatory activity and protective effect of a capsular polysaccharide in Caenorhabditis elegans, isolated from Lactobacillus fermentum GBJ.

A capsular polysaccharide, namely CPS-2, was isolated from Lactobacillus fermentum GBJ, purified using DEAE-52 anion exchange chromatography, and structurally characterized. We found that CPS-2 is homogenous, has an average molecular weight of 377 KDa, and is mainly composed of galactose and glucose at a molar ratio of 1.54:1.00. Its backbone comprises α-D-Galp-(1 â†’ 3), α-D-Galp-(1 â†’ 3,6), ß-D-Glcp-(1 â†’ 2), ß-D-Galp-(1 â†’ 6), and α-D-Galp-(1 â†’ 4) residues with a side chain of ß-D-Glcp-(1→). CPS-2 exerts an immunomodulatory effect by improving the proliferation and phagocytosis of macrophage RAW264.7 and promoting the secretion of NO and cytokines. The maximum secretion levels of IL-1ß, IL-6, IL-10, and TNF-α were 1.96-, 0.11-, 0.22-, and 0.46-fold higher than those of the control, respectively. Furthermore, CPS-2 could significantly enhance the antioxidant system, extend lifespan, and improve stress tolerance of Caenorhabditis elegans at both exposure doses of 31.25 and 62.5 µg/mL. The average lifespan of nematodes reached a maximum in the 62.5 µg/mL-treated group after 10.39 days, 6.56 h, and 23.56 h in normal, oxidative stress, and heat shock environment, with extension percentages of 16.61 %, 43.23 %, and 15.77 %, respectively; therefore, CPS-2 displays an anti-aging effect. The significant bioactivity of CPS-2 promotes its application as a promising immunomodulatory and anti-aging ingredient in the food or pharmaceutical field.

Can the Frailty of Older Adults in China Change? Evidence from a Random-Intercept Latent Transition Profile Analysis.

BACKGROUND: A major aspect of caring for older adults in the medical field is addressing their health risks. The term "frailty" is generally used to describe the changes in health risks of older adults. Although there is considerable heterogeneity in the Chinese older adult population who are classified as frail, there remain few relevant studies. Furthermore, there is a lack of research on the frailty status transitions of older Chinese adults at different time points. This research intends to determine the frailty status and category of older adults according to their physical, psychological, social, and cognitive function domains, and on this basis, to investigate changes in their frailty states. METHODS: This article studied 2791 respondents who were over 60 years old (n = 2791; 53.2% were women) from the Chinese Longitudinal Healthy Longevity Survey (CLHLS) follow-up survey on factors affecting the health of older adults in China. In this article, the frailty variables include self-reported health, social function, mental health, cognitive function, functional limitations, and morbidity status. Random-intercept latent transition profile analysis (RI-LTPA) was used to divide older adults into different subgroups, and then an in-depth analysis of the state transitions was conducted. RESULTS: The latent profile analysis revealed that the evaluation results of the frailty state of older adults showed obvious group heterogeneity. Each fitting index supported four latent states, which were named according to the degree of the symptoms (i.e., multi-frailty, severe socially frailty, mild socially frailty, and relatively healthy frailty). Based on the categorical probability and the probability of transition, it can be concluded that most of the samples belonged to the healthy population, and the health status had generally improved across the four time points. The relatively healthy frailty group and the severe socially frailty group have relatively strong stabilities. The multi-frailty group and the mild socially frailty group had the highest probability of joining to the relatively healthy frailty group. Strengthening social interactions among older adults and promoting their participation in social activities can significantly improve their frail state. CONCLUSIONS: This study supplements related research on frailty. Firstly, it deepens the meaning of frailty, which is defined based on four aspects: physical, psychological, cognitive, and social functioning. Secondly, it divides frailty into different sub-categories. Frailty is discussed from the perspective of longitudinal research, which can provide practical adjustment suggestions for older adult nursing intervention systems and measures in China.

Identifying and assessing the multiple effects of informal environmental regulation on carbon emissions in China.

Against the backdrop of the global carbon peak and carbon neutrality goals, the role of informal environmental regulation, epitomized by public engagement, is assuming an increasingly pivotal position within the realm of environmental management. By contrast, amidst the prevailing landscape dominated by formal environmental regulation (command-and-control and market-driven approaches), the environmental effects of informal environmental regulation on carbon emissions have received scant attention. Consequently, we examine the net, nonlinear, and mediation effects of informal environmental regulation on carbon emissions using panel data from 30 provinces in China, from 2003 to 2019. We find that informal environmental regulation has a significant effect on regional carbon emission reduction, especially in the eastern cities, pilot cities, and cities with long-term governor's tenure. Its U-shaped effect is confirmed by changes in environmental decentralization. The key points remain valid after the robustness test and the endogenous processing. The mechanism analysis shows that informal environmental regulation can reduce carbon emissions in the dual channels by improving industrial structure transition and renewable energy substitution. Therefore, this study assesses the management effectiveness of informal environmental regulation and determines the underlying mechanism between it and regional carbon emission reduction to provide a reference and an empirical basis for other countries regarding environmental improvement.

The impacts of industrial collaborative agglomeration on industrial sulfur dioxide emissions in China: from the novel perspective of spatiotemporal matrix.

This paper explores the impacts of industrial collaborative agglomeration on industrial sulfur dioxide intensity from a spatiotemporal perspective based on panel data on the 284 prefecture-level cities from 2003 to 2019, with systematic consideration of the underlying mechanism of channels and actions. The empirical results show that industrial co-agglomeration significantly intensifies industrial SO2 intensity, especially with increasing agglomeration. In addition, its positive spatial spillover effects are established in geographical proximity to the city. Furthermore, the channel analysis shows that the industrial structure path, industrial efficiency path, and industrial scale path account for a sharp increase in industrial SO2 intensity. The market forces reverse and moderate this exacerbating process more significantly than the government does, which provides evidence for the importance of pursuing a dynamic equilibrium between them. Finally, there exist heterogeneous effects across cities with different administrative levels, innovation capacities, and macropolicies of special emission limits for air pollutant policy. While arguing for the environmental pollution effects of industrial co-agglomeration, this paper also provides solid support and a new perspective for promoting sustainable economic development and achieving win-win economic and environmental benefits.

Explaining and modeling the impact of industrial co-agglomeration on regional economic growth in China: integrated a quality concern of night-time light perspective.

The double-wheel drive of manufacturing industries and producer services industries is one of the key pathways to promote high-quality development relying on a modern industrial system. This paper explores the impacts of industrial co-agglomeration on regional economic growth in China with systematic consideration of static, dynamic, and spatio-temporal perspectives based on panel data for 285 prefecture-level cities from 2003 to 2020, employing the consolidated night-time light data. The empirical results show that industrial co-agglomeration significantly accelerates regional economic growth, especially high-tech intensity producer services industries, information industries, and finance industries. In addition, its spatial spillover effects are evidently established, which are characterized by cyclic accumulative, feedback features, and distance attenuation. Carrying out robustness tests, the preliminary regression results are verified. The heterogeneous influences are established across cities with different geographical locations, innovation capacities, and resource endowments. The further mechanism analysis indicates that industrial upgrading, technological progress, and efficiency enhancements account for the main channels for a sharp promotion in regional economic growth over the sample period. Furthermore, the government moderates this process more significantly than market forces do, especially when it comes to macroexogenous shocks that are regulated by the government. The findings of this study recommend policymakers to give full play to the positive externalities of industrial co-agglomeration and accelerate the industrial co-agglomeration process in a reasonable manner, so as to promote high-quality economic growth in China.

Identifying impacts of industrial co-agglomeration on carbon emissions: Evidence from China.

Based on panel data of 285 cities in China at the prefecture level and above from 2005 to 2020, this paper aims to study the nexus between industrial co-agglomeration and carbon emissions from dual perspectives including space and time. It adopts multiple approaches including a dynamic general method of moment, panel quantile regression model, panel threshold model, and dynamic spatial Durbin model. The non-spatial empirical results support the establishment of the threshold effect and the imbalance effect. The spatial empirical results indicate that industrial co-agglomeration poses a dramatic stimulating effect on urban carbon emissions, and its spatial spillover effect and spatial heterogeneity are conditionally established. Furthermore, heterogeneous effects are supported, such as the positive spillover effects of industrial co-agglomeration are more significant in western cities, resource-oriented cities, and non-low-carbon pilot cities. The heterogeneous influence of cost factors on industrial agglomeration and carbon emissions has also been partially confirmed. In terms of the channels and mechanism of action, the negative externalities of industrial co-agglomeration occupy a dominant position in the current status of economic development. The dynamic equilibrium between government intervention and marketization is a solid foundation for the optimization of carbon emission reduction paths.

The effectiveness of smart city policy on pollution reduction in China: new evidence from a quasi-natural experiment.

Based on panel data of 285 prefecture-level and above cities in China from 2003 to 2020, this study has explored the impacts of smart city policy (SCP) on environmental pollution by utilizing the difference-in-differences (DID) model and its derived models. The results indicate that SCP can significantly reduce environmental pollution, and this conclusion still holds after passing numerous robustness tests, such as the propensity-score-matching difference-in-differences (PSM-DID) test, the placebo test, all independent variables lagging one period test, the policy interference test, and the instrument variable (IV) test. Moreover, the heterogeneity analysis shows that the effect of reducing environmental pollution of SCP is heterogeneous. Furthermore, the results of the spatial difference-in-differences (SDID) model show that SCP has a "beggar-thy-neighbor" effect among the pilot cities, and there is no spillover effect of SCP on pollution reduction in neighboring non-pilot cities. Finally, the analysis of moderating effect reflects that the government intervention plays a negative inhibition role in the process of SCP affecting environmental pollution, while the market competition plays a positive catalytic role in the process of SCP reducing environmental pollution.

The Impact of Financial Literacy on Household Health Investment: Empirical Evidence from China.

Based on the 2019 China Household Finance Survey (CHFS) data, this paper used factor analysis to measure the level of financial literacy of surveyed householders and used the Probit model and the negative binomial model to test the impact of financial literacy (FL) on household health investment (HHI). The results show that: (1) FL is an essential influencing factor in increasing participation in HHI, and householders with a higher level of FL are also more willing to pay for diversified investments. (2) We split the FL level from the two dimensions of knowledge and ability. We found that the primary FL (including financial knowledge, computing ability, and correct recognition of investment product risk) plays a more critical role in the investment decision process. (3) When information sources, health knowledge, and family income are used as mediating variables, FL can influence the decisions of HHI in three ways: expanding information sources, enriching health knowledge, and alleviating income constraints. (4) By analyzing the heterogeneity of household heads in different regions and with different personal characteristics, we found that the medical level of the household location and the life and work experience of the householders played a moderating role.

Comparison of Ray Tracing and Monte Carlo Calculation Algorithms for Spine Lesions Treated With CyberKnife.

Purpose: This study attempts to evaluate Ray Tracing (RT) and Monte Carlo (MC) algorithms for CyberKnife treatments of spine lesions and determine whether the MC algorithm is necessary for all spine treatment and compare the RT algorithm and MC algorithm at various spine lesion sites. Methods: The CyberKnife is used for stereotactic body radiotherapy for lesions in the cervical spine (30), thoracic spine (50), lumbar spine (30), and sacral spine (15). Dose was calculated using RT and MC algorithms for patients planned with the same beam angles and monitor units. Dose-volume histograms of the target and selected critical structures are evaluated. Results: The average target coverage of prescribed dose with MC algorithms was 94.80%, 88.47%, 92.52%, and 93.41%, respectively, in cervical, thoracic, lumbar, and sacral spine. For the thoracic spine, the RT algorithm significantly overestimates the percentage volume of the target covered by the prescribed dose, as well as overestimates doses to organs at risk in most cases, including lung, spinal cord, and esophagus. For cervical, lumbar, and sacral spine, the differences of the target coverage of prescription dose were generally less than 3% between the RT and MC algorithms. The differences of doses to organs at risk varied with lesion sites and surrounding organs. Conclusions: In the thoracic spine lesions with beams through air cavities, RT algorithm should be limited and verified with MC algorithm, but the RT algorithm is adequate for treatment of cervical, lumbar, and sacral spine lesions without or with a small amount of beams passing through the lungs.

Assessment of Delivery Quality Assurance for Stereotactic Radiosurgery With Cyberknife.

PURPOSE: The purpose of this study is to establish and assess a practical delivery quality assurance method for stereotactic radiosurgery with Cyberknife by analyzing the geometric and dosimetric accuracies obtained using a PTW31016 PinPoint ionization chamber and EBT3 films. Moreover, this study also explores the relationship between the parameters of plan complexity, target volume, and deliverability parameters and provides a valuable reference for improving plan optimization and validation. METHODS: One hundred fifty cases of delivery quality assurance plans were performed on Cyberknife to assess point dose and planar dose distribution, respectively, using a PTW31016 PinPoint ionization chamber and Gafchromic EBT3 films. The measured chamber doses were compared with the planned mean doses in the sensitive volume of the chamber, and the measured planar doses were compared with the calculated dose distribution using gamma index analysis. The gamma passing rates were evaluated using the criteria of 3%/1 mm and 2%/2 mm. The statistical significance of the correlations between the complexity metrics, target volume, and the gamma passing rate were analyzed using Spearman's rank correlation coefficient. RESULTS: For point dose comparison, the averaged dose differences (± standard deviations) were 1.6 ± 0.73% for all the cases. For planar dose distribution, the mean gamma passing rate for 3%/1 mm, and 2%/2 mm evaluation criteria were 94.26% ± 1.89%, and 93.86% ± 2.16%, respectively. The gamma passing rates were higher than 90% for all the delivery quality assurance plans with the criteria of 3%/1 mm and 2%/2 mm. The difference in point dose was lowly correlated with volume of PTV, number of beams, and treatment time for 150 DQA plans, and highly correlated with volume of PTV for 18 DQA plans of small target. DQA gamma passing rate (2%/2 mm) was a moderate significant correlation for the number of nodes, number of beams and treatment time, and a low correlation with MU. CONCLUSION: PTW31016 PinPoint ionization chamber and EBT3 film can be used for routine Cyberknife delivery quality assurance. The point dose difference should be within 3%. The gamma passing rate should be higher than 90% for the criteria of 3%/1 mm and 2%/2 mm. In addition, the plan complexity and PTV volume were found to have some influence on the plan deliverability.

Using Generalizability Theory and Many-Facet Rasch Model to Evaluate In-Basket Tests for Managerial Positions.

Purpose: This study aimed to analyze interview data collected from a series of in-basket tests during managerial personnel recruitment in a local Chinese company, taking advantage of the use of combination of Generalizability theory (GT) and Many-facet Rasch Model (MFRM), rather than the Classical Test Theory (CTT). Design/Methodology/Approach: Participants included 78 candidates (M age = 37.76, SD = 6.36; 35.9% female) interviewed for eight managerial positions in a local Chinese company. Data were collected based on a series of 10 in-basket interview tests, and a 20-item rating scale (the in-basket test rating scale; IBTRS) was developed and piloted, and five expert raters rated the participants on their performance in five aspects (planning, communication and coordination, capital operations and management, analysis and problem solving, and empowerment and controlling). The data were analyzed using a crossed design of p × i × r, where p represents person, i represents item, and r represents rater. Effects of candidate (person), test item, rater, and the interaction of item and rater were examined. Findings: The use of the combination of GT and MFRM was able to provide accurate, comprehensive information over the process of in-basket interview tests. Specifically, GT analysis showed good generalization coefficient and reliability index (0.893 and 0.871, respectively), and the variation of candidates explained most of the total variance (53.22%). The candidates scored high in the dimension of empowerment and controlling. There were differences in the severity of raters. Three raters should be sufficient to ensure good scoring stability. Originality/Value: This study used the combination of GT and MFRM to assess the interview data instead of using a CTT approach.

Establishment of Silane/GO Multistage Hybrid Interface Layer to Improve Interfacial and Mechanical Properties of Carbon Fiber Reinforced Poly (phthalazinone ether ketone) Thermoplastic Composites.

This study focused on the faint interface bonding between carbon fiber (CF) and poly(phthalazinone ether ketone) (PPEK) thermoplastic, a multistage hybrid interface layer was constructed via the condensation reaction of N-[3-(Trimethoxysilyl)propyl]-N,N,N-trimethylammonium chloride (KHN+) and the electrostatic adsorption of graphene oxide (GO). The influence of the contents of GO (0.2 wt%, 0.4 wt%, 0.6 wt%) on the interfacial properties of composites was explored. FTIR, Raman spectra, XPS tests indicated the successful preparation of CF-KHN+-GO reinforcements. The multistage hybrid interface layer significantly increased fiber surface roughness without surface microstructure destruction. Simultaneously, polarity and wettability are remarkably improved as evidenced by the dynamic contact angle experiment. The interlaminar shear strength (ILSS) and flexural strength of the CF/PPEK composites with 0.4 wt% GO (CF-KHN+-4GO) were 74.57 and 1508 MPa, which was 25.2% and 23.5% higher than that of untreated CF/PPEK composite, respectively. Dynamic mechanical analysis proved that CF/GO/PPEK composites have excellent high-temperature mechanical properties. This study furnishes an unsophisticated and valid strategy to build an interface transition layer with a strong binding force, which would offer a new train of thought in preparing high-performing structural composites.

National survey of patient specific IMRT quality assurance in China.

BACKGROUND: To analyze and present the China's national survey on patient-specific IMRT quality assurance (QA). METHODS: A national survey was conducted in all radiotherapy centers in China to collect comprehensive information on status of IMRT QA practice, including machine, technique, equipment, issues and suggestions. RESULTS: Four hundred and three centers responded to this survey, accounting for 56.92% of all the centers implementing IMRT in China. The total number of medical physicists and the total number of patients treated with IMRT annually in these centers was 1599 and 305,000 respectively. All centers implemented measurement-based verification. Point dose verification and 2D dose verification was implemented in 331 and 399 centers, respectively. Three hundred forty-eight centers had 2D arrays, and 52 centers had detector devices designed to measure VMAT beams. EPID and film were used in 78 and 70 centers, respectively. Seventeen and 20 centers used log file and 3D DVH analysis, respectively. One hundred sixty-eight centers performed measurement-based verification not for each patient based on different selection criteria. The techniques and methods varied significantly in both point dose and dose distribution verification, from evaluation metrics, criteria, tolerance limit, and steps to check failed IMRT QA plans. Major issues identified in this survey were the limited resources of physicists, QA devices, and linacs. CONCLUSIONS: IMRT QA was implemented in all the surveyed centers. The practice of IMRT QA varied significantly between centers. An increase in personnel, QA devices and linacs is highly desired. National standard, guideline, regulation and training programs are urgently needed in China for consistent and effective implementation of IMRT QA.

Investigation of sweet potato starch as a structural enhancer for three-dimensional printing of Scomberomorus niphonius surimi.

Three-dimensional printing (3DP) of surimi requires a structural modifier to achieve a stable construct. This work investigated the effect of addition of sweet potato starch (0-10% wt/wt) on the physical properties (rheological properties, gel strength, water-holding capacity [WHC], and microstructural characteristics) of surimi gels and the 3D printed behavior of these gels. The results showed that as the starch content increased, the viscosity of the starch-surimi mixture decreased facilitating the flow of the surimi out of the printer nozzle. The surimi gel with 8% sweet potato starch concentration showed good gel strength (2,021.70 g mm), WHC (82.39%), microstructural characteristics, and less cooking loss (1.95%). A comparison of the traditional surimi preparation method with 3DP showed that the surimi gel prepared by a 3D printed construct was softer in gel strength (1,398.65 g mm) and lower in hardness (945.17 g) although showing slightly higher cooking loss (6.76%) and lower WHC (72.66 g) than the conventional product. The results suggest that sweet potato starch can be effectively used as a structural enhancer for 3DP complex-shaped surimi.

Establishment of detailed respiratory tract model and Monte Carlo simulation of radon progeny caused dose.

As radon is one of the most important natural radiation sources, its radiation hazard has always been a concern. α and ß particles emitted by short-lived radioactive radon progeny nuclides could result in a high local dose and induce radiation damage to the respiratory tract. A detailed respiratory tract model needs to be built and dose distribution in the respiratory tract should be studied to reflect the characteristics of energy deposition caused by radon and its progeny. Therefore, in the present work, a dosimetric study was conducted on the respiratory tract and non-uniform dose distribution in the bronchial region was studied. First, a detailed voxel respiratory tract model was established based on the anatomic bronchial parameters of an adult Chinese male. The dimensional parameters of the tracheo-bronchial tree of an adult male adopted in ICRP Publication 66 (ICRP 1994 Human Respiratory Tract Model for Radiological Protection ICRP Publication 66 (Oxford: Pergamon)), featured by consecutive 16 generations of bronchi structures to express the irregular structure of the respiratory tract and the radiosensitive tissues in the bronchial region, were also built for dosimetric study. Then the deposition and clearance models recommended by ICRP were used to analyse the regional deposition and transfer in the respiratory tract, and a fluid dynamic simulation was used to obtain 3D distribution of radon progeny aerosol particles in the bronchial region. The result showed that the highest deposition fraction density occurs at the first and second generations of bronchi. Furthermore, the detailed voxel respiratory tract model along with the Monte Carlo method were used to obtain dose distribution in the BB region. It was found that the dose distribution in the respiratory tract is very non-uniform and the maximum voxel dose is about 30 times higher than the average voxel dose. The dose conversion factor (DCF) for lung in the home environment derived with the dosimetry method in the present work is 9.86 mSv·WLM-1. Sensitivity analysis was performed for the parameters involved in the DCF calculation and it was found that the unattached fraction and breathing rate influence the DCF the most.

Film-based dose validation of Monte Carlo algorithm for Cyberknife system with a CIRS thorax phantom.

Monte Carlo (MC) simulation, as the most accurate dose calculation algorithm, is available in the MultiPlan treatment planning system for Cyberknife. The main purpose of this work was to perform experiments to thoroughly investigate the accuracy of the MC dose calculation algorithm. Besides the basic MC beam commissioning, two test scenarios were designed. First, single beam tests were performed with a solid water phantom to verify the MC source model in simple geometry. Then, a lung treatment plan on a CIRS thorax phantom was created to mimic the clinical patient treatment. The plan was optimized and calculated using ray tracing (RT) algorithm and then recalculated using MC algorithm. Measurements were performed in both a homogeneous phantom and a heterogeneous phantom (CIRS). Ion-chamber and radiochromic film were used to obtain absolute point dose and dose distributions. Ion-chamber results showed that the differences between measured and MC calculated dose were within 3% for all tests. On the film measurements, MC calculation results showed good agreements with the measured dose for all single beam tests. As for the lung case, the gamma passing rate between measured and MC calculated dose was 98.31% and 97.28% for homogeneous and heterogeneous situation, respectively, using 3%/2 mm criteria. However, RT algorithm failed with the passing rate of 79.25% (3%/2 mm) for heterogeneous situation. These results demonstrated that MC dose calculation algorithm in the Multiplan system is accurate enough for patient dose calculation. It is strongly recommended to use MC algorithm in heterogeneous media.

Development of 1-year-old computational phantom and calculation of organ doses during CT scans using Monte Carlo simulation.

With the rapidly growing number of CT examinations, the consequential radiation risk has aroused more and more attention. The average dose in each organ during CT scans can only be obtained by using Monte Carlo simulation with computational phantoms. Since children tend to have higher radiation sensitivity than adults, the radiation dose of pediatric CT examinations requires special attention and needs to be assessed accurately. So far, studies on organ doses from CT exposures for pediatric patients are still limited. In this work, a 1-year-old computational phantom was constructed. The body contour was obtained from the CT images of a 1-year-old physical phantom and the internal organs were deformed from an existing Chinese reference adult phantom. To ensure the organ locations in the 1-year-old computational phantom were consistent with those of the physical phantom, the organ locations in 1-year-old computational phantom were manually adjusted one by one, and the organ masses were adjusted to the corresponding Chinese reference values. Moreover, a CT scanner model was developed using the Monte Carlo technique and the 1-year-old computational phantom was applied to estimate organ doses derived from simulated CT exposures. As a result, a database including doses to 36 organs and tissues from 47 single axial scans was built. It has been verified by calculation that doses of axial scans are close to those of helical scans; therefore, this database could be applied to helical scans as well. Organ doses were calculated using the database and compared with those obtained from the measurements made in the physical phantom for helical scans. The differences between simulation and measurement were less than 25% for all organs. The result shows that the 1-year-old phantom developed in this work can be used to calculate organ doses in CT exposures, and the dose database provides a method for the estimation of 1-year-old patient doses in a variety of CT examinations.