ObjectiveThe outbreak of COVID-19 pandemic has greatly impacted on radiotherapy (RT) strategy for breast cancer patients, which might lead to increased distressing psychological symptoms. We performed a multi-center cross-section survey to investigate prevalence of fear of cancer recurrence (FCR) and predictors for FCR in patients referred to RT during pandemic.Methods542 patients were consecutively enrolled from three regions in China including Yangtze Delta River Region, Guangdong and Shanxi province. Patients’ characteristics were collected using an information sheet, Fear of progression questionnaire-short form, Hospital Anxiety/Depression Scale and EORTC QLQ-C30. The hierarchical multiple regression models were performed.Results488 patients with complete data were eligible. The RT strategy was affected in 265 (54.3%) patients, including 143 with delayed RT initiation, 66 believing to have delayed RT initiation but actually not, 24 with RT interruptions, 19 shifting to local hospitals for RT and the remaining 13 influenced on both RT schedule and hospital level. The model explained 59.7% of observed variances in FCR (p<0.001) and showed that influence of RT strategy had significantly impacted on FCR (△R2 = 0.01, △F=2.966, p=0.019). Hospitals in Shanxi province (β=-0.117, p=0.001), emotional function (β=-0.19, p<0.001), social function (β=-0.111, p=0.006), anxiety (β=0.434, p<0.001) and RT interruption (β=0.071, p=0.035) were independent predictors.ConclusionsRT strategy for breast cancer patients was greatly influenced during pandemic. RT interruption is an independent predictor for high FCR. Our findings emphasize the necessity to ensure continuum of RT, and efforts should be taken to alleviate FCR through psychological interventions.
Steel fibers are widely used because they can effectively improve the tensile, compressive and flexural properties of concrete structures. The selection of steel fiber dosage and aspect ratio at high temperature has an important impact on the flexural toughness of concrete components post-fire. In this paper, discussions are made on the simulated fire test in compliance with the ISO 834 standard to study the steel fiber-reinforced concrete (SFRC) components post-fire. The research reveals the influence of two commonly used steel fiber aspect ratios (50, 70) and steel fiber dosages (30 kg/m3, 40 kg/m3, 45 kg/m3) on the changes of the internal temperature field, the initial crack flexural strength and the flexural toughness of the SFRC components under a single-side fire. Moreover, combined with the four-point flexural test of the SFRC components post fire, the research also describes the damage of high temperatures to the flexural toughness of SFRC components, and suggests a calculation formula for SFRC thermal conductivity by way of the numerical inversion method. The results of this study have verified that the incorporation of steel fiber into concrete helps to reduce its internal thermal stress difference and improve the crack resistance and fire resistance of the concrete. Moreover, under high temperature conditions, the concrete component added with the steel fiber in an aspect ratio of 70 and a dosage of 45 kg/m3 increased their initial crack flexural strength by 56.8%, higher than that of plain concrete components, and the loss of equivalent flexural strength and flexural toughness of SFRC post fire was only 45.2% and 13.6%, respectively. The proposed calculation formula of thermal conductivity can provide a reference for a numerical simulation study of the temperature field of SFRC components in a high temperature environment.
Stochastic partial differential equations (SPDEs) are significant tools for modeling dynamics in many areas including atmospheric sciences and physics. Neural Operators, generations of neural networks with capability of learning maps between infinite-dimensional spaces, are strong tools for solving parametric PDEs. However, they lack the ability to modeling SPDEs which usually have poor regularity 1 due to the driving noise. As the theory of regularity structure has achieved great successes in analyzing SPDEs and provides the concept model feature vectors that well-approximate SPDEs' solutions, we propose the Neural Operator with Regularity Structure (NORS) which incorporates the feature vectors for modeling dynamics driven by SPDEs. We conduct experiments on various of SPDEs including the dynamic Φ 4 1 model and the 2d stochastic Navier-Stokes equation, and the results demonstrate that the NORS is resolution-invariant, efficient, and achieves one order of magnitude lower error with a modest amount of data.
As a new type of pre-reinforcement material for tunnel faces, glass fiber-reinforced polymer (GFRP) bolts can effectively and safely improve the stability of tunnel faces in soft surrounding rocks and speed up excavation. Therefore, in this paper, systematic research is carried out on the bond strength of GFRP bolts in tunnel faces and their relative pre-reinforcement parameters. Firstly, the effects of rebar diameter, anchorage length, and mortar strength on the bonding properties of GFRP bars were studied by indoor pull-out tests. The bond strength–slip curves under different working conditions were obtained, and the curves showed that the ultimate bond strength between GFRP bars and mortar was negatively correlated with the diameter of GFRP bars but positively correlated with the strength of the mortar. In addition, the increase in anchorage length led to a reduction in bonding strength. Secondly, inverse analysis was used to analyse the mechanical parameters of the bond performance of the anchor bars by the finite difference software FLAC3D, and the results indicated that 1/5 of the compressive strength of the GFRP bar grouting body can be taken as the ultimate bond strength to calculate the cohesive strength of the grout. Additionally, the formula of GFRP bar grouting body stiffness was revised. Finally, based on the results of laboratory tests and the inverse analysis, the numerical simulation analysis results showed that the optimal reinforcement configuration for a shallow buried tunnel face surrounded by weak rock is to use GFRP bars with a length of 17 m arranged in the center circle of the tunnel face with a reasonable reinforcement density of 1.0 bolt/m2. The calculation formula of the stiffness and cohesion strength of the GFRP bar grouting body and the reinforcement scheme proposed in this paper can provide a reference for the construction of shallowly buried rock tunnels in soft surrounding rock.
Background The outbreak of COVID-19 pandemic in China has greatly impacted the radiotherapy (RT) strategy for breast cancer (BC) patients, which might lead to an increased distressing psychological symptom. Thus, we perform a multi-center cross-section survey aiming to investigate the prevalence of fears of cancer recurrence (FCR) and explore predictors for FCR in BC patients referred for RT during pandemic. Methods: 542 BC patients who referred for RT between 24th Jan and 30th April 2020 during pandemic were consecutively enrolled from 14 hospitals around China including Yangtze Delta River Region, Guangdong and Shanxi province. Patients’ sociodemographic, treatment information as well as psychological characteristics were collected using an information sheet, Fear of progression questionnaire-short form (FoP-Q-SF), Hospital Anxiety and Depression Scale (HADS) and EORTC QLQ-C30. The influence of pandemic on RT schedule was divided into four categories: “delay” was defined as >12 weeks from surgery to RT in patients without chemotherapy or >8 weeks from last time of anti-tumor therapy (including chemotherapy and surgery) to RT in patients with chemotherapy; “Special normal” was defined that patients themselves believed to have delayed RT initiation but actually not; “Interruption” was defined as any unplanned gaps in original RT regime and all other would be classified into “normal”. Another type of influence on RT strategy was that patients had to shift planned RT hospital from Grade-A tertiary hospital to local hospitals. Univariable analyses of FCR were performed in a one-way analysis of variance (ANOVA) or student t-test or Pearson correlation analyses and candidate variables with P<0.2 were included Hierarchical multiple regression models to investigate predictors for FCR. Guangdong province was chosen as reference in models. Results 488 patients with complete data were eligible for the present analysis and none of patients and their family members had been diagnosed as COVID-19. The RT strategy was affected in 265 (54.3%) patients, including 143 with delayed RT initiation, 66 with “special normal” schedule, 24 (4.9%) with RT interruptions, 19 shifting to local hospitals for RT, and the remaining 13 being influenced on both RT schedule and planned RT hospitals. Most of patients with affected RT strategy occurred in late January and February, when was peak of COVID-19 pandemic in China. The mean FCR scores was 24.83 (SD=8.554) and 84 patients (17.3%) were classified as dysfunctional level of FCR (sum score ≥34). In univariable analyses, FCR were significantly higher in patients who received RT in Guangdong province and in hospitals with < 100 BC cases per year. In term of during pandemic, a significant difference in FCR was observed in terms of influence on RT schedule (p<0.001). and changes of hospital levels(p=0.009). There were significant correlations between FCR and anxiety/depressive in HADS or all five function scales (physical, role, emotional, cognitive and social) and global QoL in QLQ-C30 (p<0.001). Finally, the model explained 59.7% of observed variances in FCR and showed that influence of RT strategy during pandemic had significantly impacted on FCR (ΔR2=0.01, ΔF=2.966, p=0.019). Hospitals in Shanxi province (β=-0.117, p=0.001), emotional function (β=-0.19, p<0.001), social function (β=-0.111, p=0.006), anxiety (β=0.434, p<0.001) and RT interruption (β=0.071, p=0.035) were independent predictors for FCR. Conclusions RT strategy for BC patients was greatly influenced during pandemic. RT interruption is an independent predictor for high FCR. Our findings emphasize the necessity to ensure the continuum of RT in BC patients, and efforts should be taken to alleviate the FCR through psychological interventions. Citation Format: Jinrong Xie, Weixiang Qi, Lu Cao, Yuting Tan, Jin Huang, Xiaodong Gu, Bingguang Chen, Peipei Shen, Ying Zhang, Qingwen Zhao, Hecheng Huang, Yubin Wang, Haicheng Fang, Zhenjun Jin, Hui Li, Xuehong Zhao, Xiaofang Qian, Feifei Xu, Dan Ou, Shubei Wang, Cheng Xu, Min Li, Zefei Jiang, Yu Wang, Xiaobo Huang, Jiayi Chen. Predictors for fear of cancer recurrence in breast cancer patients referred for radiation therapy during the COVID-19 pandemic: A multi-center cross-section survey [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr SS2-07.
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