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The selection of adaptive strategies in MR-guided adaptive radiotherapy (MRgART) usually relies on subjective review of anatomical changes. However, this kind of review may lead to improper selection of adaptive strategy for some fractions.The purpose of this study was to develop prediction models based on deformation vector field (DVF) features for automatic and accurate strategy selection, using prostate cancer as an example.100 fractions of 20 prostate cancer patients were retrospectively selected in this study. Treatment plans using both adapt to position (ATP) strategy and adapt to shape (ATS) strategy were generated. Optimal adaptive strategy was determined according to dosimetric evaluation. DVFs of the deformable image registration (DIR) of daily MRI and CT simulation scans were extracted. The shape, first order statistics, and spatial features were extracted from the DVFs, subjected to further selection using the minimum redundancy maximum relevance (mRMR) method. The number of features (FAccording to subjective review, the ATS strategy was adopted for all 100 fractions. However, the evaluation results showed that the ATP strategy could have met the clinical requirements for 23 (23%) fractions. The three prediction models showed high prediction performance, with the best performing model achieving an AUC value of 0.896, corresponding accuracy (ACC), sensitivity (SEN) and specificity (SPC) of 0.9, 0.958, and 0.667, respectively. The features used to construct prediction models included 4 features extracted from y direction of DVF (DVFDVF-feature-based models could accurately predict the adaptive strategy and avoid unnecessary selection of time-consuming ATS strategy, which consequently improves the efficiency of the MRgART process. This article is protected by copyright. All rights reserved.

Background This study aimed to evaluate the feasibility and safety of online adapt-to-shape (ATS) workflow for prostate cancer patients on 1.5-T MR linac in China. Methods This prospective phase II study enrolled patients with localized or oligometastatic prostate cancer. Ultra-hypofractionated radiotherapy (UHF-RT) with dose of 36.25-40 Gy in five fractions was delivered every other day. After each fraction, feasibility and tolerability of the treatment were assessed. The primary endpoints were acute grade 2 or above genitourinary (GU) and gastrointestinal (GI) toxicities after up to 12 weeks follow-up.Results From March 2021 to November 2021, 26 patients were enrolled (23 with localized prostate cancer, 3 with oligometastatic prostate cancer). For all fractions, the online ATS plans met the dose criteria for both the target volume and normal tissues. The median on-couch time was 55 (34-95) minutes and 39 (24-50) minutes with T2WI 6-minute sequence and 2-minute sequence scans, respectively. For 98.4% fractions, treatment was well tolerated. Twenty-four patients completed treatment and were followed-up for at least 2 weeks. Grade 2 or above GU and GI toxicities occurred in 33.3% and 8.3% patients, respectively; two patients had RTOG grade 3 GU toxicity (hourly nocturia). IPSS remained unchanged during UHF-RT, increased from week 2 (mean, 9.1) to week 4 (mean, 12.4), and then gradually decreased at week 6. Patient-reported urinary and bowel scores were consistent with IPSS.Conclusions UHF-RT with ATS workflow is well tolerated by patients with localized and oligometastatic prostate cancer, with only moderate GU and mild GI toxicities. Trial Registration: NCT05183074, ChiCTR2000033382

Jet flow that the engine generates can cause serious damage to facilities and equipment in narrow space. In order to solve this problem, the lowest silencer unit in the silencer layer was selected as research object. The highest temperature of jet flow near silencer unit and thermo-physical parameters at that moment were taken as initial conditions to research on heat transfer. By using the MATLAB software, the heat transfer between jets flow and silencer layer was calculated, the temperature distribution inside silencer layer at different time was obtained, and the law of heat transfer was concluded, which could provide some theoretical basis for the design and upgrading of narrow space.

The objective of this work was to investigate the color, transparency, water sensitivity and mechanical properties stability in air under photo-oxidative degradation influencing consumer acceptance and biodegradation behaviors in soil of soy protein isolate (SPI)/poly (vinyl alcohol) (PVA) blend packaging films during 30 days. The results showed that PVA could dilute the yellow color and make the SPI-based films less darkness in application and the transparency of SPI/PVA films at various stages of degradation was improved. The addition of PVA decreased the ability of SPI protein molecules to absorb water and enhanced the mechanical properties of blend films comparing to pure SPI film in 30 days. Aerobic biodegradation of films in soil proved that the PVA compound interacting with protein imposed negative effects on biodegradation of blend films prolonging their decomposing time. The SPI/PVA blend films decomposed into small fragments of less complex molecules along with surface completely digested after 30 days.

To promote the heat-sealing properties of soy protein isolate (SPI) films applied in the packaging field, we mixed a synthetic polymer of poly(vinyl alcohol) (PVA) with SPI to fabricate blend films by a solution-casting method in this study. To clarify the relationship between the heat-sealing properties and the heat-sealing temperature, strength, melting process, crystalline structure, and microstructure, variations of the heat-sealing parts of the films were evaluated by means of differential scanning calorimetry, tensile testing, scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy, respectively. The test results showed that both the PVA and glycerol contents greatly affected the melting behavior and heat of fusion of the SPI/PVA blends; these blend films had a higher melting temperature than the pure SPI films. The peel strength and tensile strength tests indicated that the long molecular chain of PVA had a main function of enhancing the mechanical properties above the melting temperature. With increasing heat-sealing temperature, all of the mechanical properties were affected by the microstructure of the interface between the laminated films including the chain entanglement, crystallization, and recrystallization. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

The aim of the present work was to investigate the moisture sensitivity of soy protein isolate (SPI) films blending with poly (vinyl alcohol) (PVA) plasticized by glycerol. Water vapor permeability (WVP) was measured based on the contents of PVA and glycerol in films. WVP values of various SPI/PVA films with/without glycerol were in the range of 8.25 and 10.9 g mm/m2 h kPa. The results showed that WVP values decreased with the increasing content of PVA. Moreover, XRD tests confirmed that the glycerol would insert into the macromolecular blending structure and destroy the crystalline of blends, and the crosslinkage between glycerol molecules and SPI reduced the interstitial spaces in protein matrix, thus allowing for decreasing diffusion rate of water molecules through the films.