Background
Optical metrology is widely used to measure materials’ deformation and mechanical properties but current fundamental research requires more precise measurement of microstructure and ...deformation in internal materials. Electron backscattered diffraction (EBSD) technique measures crystal orientation in individual grain and high resolution EBSD (HR-EBSD) method provides information about residual strain and GND density.
Objective
Deformation of two stainless steels Nitronic 60 and Tristelle 5183 with different proportions of ferrite and carbides are characterised.
Methods
Push-release bend testing was used to provide progressive increasing bending stress in two iron-based material samples. HR-EBSD and high resolution digital image correlation (HR-DIC) methods characterised residual strain, GND density and plastic strain distributions in each sample.
Results
Nitronic 60 and Tristelle 5183 were deformed and obtained 3.8% and 0.9% plastic strain Ɛxx. High GND densities distributed neighbouring grain boundaries in Nitronic 60 while high GND densities distributed around carbides, especially intragranular carbides in Tristelle 5183.
Conclusions
HR-EBSD and HR-DIC quantitative characterised deformation in two iron-based alloys, grain/twin boundaries and carbides resulted in GND density increase, promoted work hardening and accumulated high residual elastic strain. Heterogeneous grain/carbide size distribution leaded to stress concentration and cause carbide decohesion and brittle fracture of sample.
Strong interplanetary shock interactions with the Earth's magnetosphere have great impacts on energetic particle dynamics in the magnetosphere. An interplanetary shock on 7 November 2004 (with the ...maximum solar wind dynamic pressure of ∼70 nPa) was observed by the Cluster constellation to induce significant ULF waves in the plasmasphere boundary, and energetic electrons (up to 2 MeV) were almost simultaneously accelerated when the interplanetary shock impinged upon the magnetosphere. In this paper, the relationship between the energetic electron bursts and the large shock‐induced ULF waves is studied. It is shown that the energetic electrons could be accelerated and decelerated by the observed ULF wave electric fields, and the distinct wave number of the poloidal and toroidal waves at different locations also indicates the different energy ranges of electrons resonating with these waves. For comparison, a rather weak interplanetary shock on 30 August 2001 (dynamic pressure ∼2.7 nPa) is also investigated. It is found that interplanetary shocks or solar wind pressure pulses with even small dynamic pressure change can have a nonnegligible role in the radiation belt dynamics.
Pharmacotherapy using natural substances can be currently regarded as a very promising future alternative to conventional therapy. With the rapid development of biotechnologies and analytical ...techniques, a great number of methods have been developed for the identification and quantification of the material, extracts, and products of natural ingredients. The advances available today. The need for safer drugs without side effects has led to the use of natural ingredients with proven safety. In recent years, some bioactive polysaccharides isolated from natural sources have attracted much attention in the field of biochemistry and pharmacology. As an example, polysaccharides or their glycoconjugates were shown to exhibit multiple biological activities including anticarcinogenic, anticoagulant, immunostimulating, antioxidant, etc. During the last several years, we have witnessed a steady expansion in the number of publications that focus in antioxidant polysaccharides. This review presents current findings on the latest advancements and trends in antioxidant polysaccharides isolated from the following: plants, fungi, bacteria, animal sources, and algae. Some interesting studies focus on investigation of the relationship between their structure and antioxidant activity, elucidation of their antioxidant mechanism at the molecular level, and improvement of their various biological activities by chemical modifications. Although the mechanism of their antioxidant action is still not completely clear, these polysaccharides are suggested to enhance cell-mediated immune responses in vivo and in vitro and act as biological response modifiers.
Estimation of particulate matter with aerodynamic diameter less than 2.5 μm (PM2.5) from daytime satellite aerosol products is widely reported in the literature; however, remote sensing of nighttime ...surface PM2.5 from space is very limited. PM2.5 shows a distinct diurnal cycle and PM2.5 concentration at 1:00 local standard time (LST) has a linear correlation coefficient (R) of 0.80 with daily-mean PM2.5. Therefore, estimation of nighttime PM2.5 is required toward an improved understanding of temporal variation of PM2.5 and its effects on air quality. Using data from the Day/Night Band (DNB) of the Visible Infrared Imaging Radiometer Suite (VIIRS) and hourly PM2.5 data at 35 stations in Beijing, a mixed-effect model is developed here to estimate nighttime PM2.5 from nighttime light radiance measurements based on the assumption that the DNB-PM2.5 relationship is constant spatially but varies temporally. Cross-validation showed that the model developed using all stations predict daily PM2.5 with mean determination coefficient (R2) of 0.87 ± 0.12, 0.83 ±0.10, 0.87 ± 0.09, 0.83 ± 0.10 in spring, summer, autumn and winter. Further analysis showed that the best model performance was achieved in urban stations with average cross-validation R2 of 0.92. In rural stations, DNB light signal is weak and was likely smeared by lunar illuminance that resulted in relatively poor estimation of PM2.5. The fixed and random parameters of the mixed-effect model in urban stations differed from those in suburban stations, which indicated that the assumption of the mixed-effect model should be carefully evaluated when used at a regional scale.
•A novel method is established to estimate nighttime PM2.5 from VIIRS DNB data.•Nighttime PM2.5 is estimated with determination coefficient of exceeding 0.8.•Potentials and limitations of this method are discussed.
Desmoid tumors (DTs) are rare benign neoplasms but cause significant mortality due to their locally infiltrative nature and propensity to recur. Most DTs occur in the extremities and trunk. Head and ...neck DTs are uncommon but can have a significant impact on a patient's facial appearance. However, there is limited information available about the diagnosis and treatment for multiple DTs located in head and neck. We report the first case of multiple maxillofacial DTs in a 14-year-old boy. He had painless submandibular masses for three months and MRI imaging reveals abnormal high signals on the submandibular and bilateral zygomatic regions. Considering facial aesthetics, via intraoral incision we obtained a biopsy from the largest mass. Pathological examination confirmed a diagnosis of DT. We selected the wait-and-see strategy and clinically monitored the rest of the masses. During the subsequent 1-year follow-up, the masses were stagnant and appeared to involute. According to the development and outcome of this case, a conservative treatment for craniofacial DTs is suggested; however, greater clarity concerning management and prognosis could derive from prospective study of a larger patient cohort in the future.
When Inconel 718 alloy is fabricated by selective laser melting and treated by traditional homogenization plus double aging heat treatment (HA), its strength improves greatly, but ductility ...decreases. A novel heat treatment (NHT) including higher temperature homogenization at 1150 °C for 2 h and one-time lower temperature aging treatment at 700 °C for 12 h is developed, which can overcome the strength-plasticity trade-off of Inconel 718 alloy. The results show that recrystallized grains with annealing twins and ultrafine strengthening phases form in the specimen subjected to the NHT. These microstructures differ from those in as-built and conventional heat-treated samples. Especially the morphology of strengthening phase γ″-Ni3Nb precipitated in the NHT specimen has changed a lot, it seems to be spherical rather than disc-like shape occurred in the traditional heat-treated samples. Consequently, the NHT process increases plasticity by 41%, while maintaining ultimate strength at the same level achieved by the traditional heat treatment. The enhanced ductility is attributed to the annealing twins and recrystallized grains without local strains, while the strength is provided by the smaller precipitates formed in the NHT one-time aging treatment.
Display omitted
•A novel heat treatment process was proposed for Inconel 718 superalloy.•The morphology of γ″ phase was modified by one-time aging heat treatment.•The recrystallized grains with annealing twins promoted good plasticity.
•Fast and accurate pancreatic GTV auto-segmentation in MRI using deep learning.•Model performance had no significant difference to interobserver variation.•Provide a framework for GTV ...auto-segmentation in MRgOART.
The recently introduced MR-Linac enables MRI-guided Online Adaptive Radiation Therapy (MRgOART) of pancreatic cancer, for which fast and accurate segmentation of the gross tumor volume (GTV) is essential. This work aims to develop an algorithm allowing automatic segmentation of the pancreatic GTV based on multi-parametric MRI using deep neural networks.
We employed a square-window based convolutional neural network (CNN) architecture with three convolutional layer blocks. The model was trained using about 245,000 normal and 230,000 tumor patches extracted from 37 DCE MRI sets acquired in 27 patients with data augmentation. These images were bias corrected, intensity standardized, and resampled to a fixed voxel size of 1 × 1 × 3 mm3. The trained model was tested on 19 DCE MRI sets from another 13 patients, and the model-generated GTVs were compared with the manually segmented GTVs by experienced radiologist and radiation oncologists based on Dice Similarity Coefficient (DSC), Hausdorff Distance (HD), and Mean Surface Distance (MSD).
The mean values and standard deviations of the performance metrics on the test set were DSC = 0.73 ± 0.09, HD = 8.11 ± 4.09 mm, and MSD = 1.82 ± 0.84 mm. The interobserver variations were estimated to be DSC = 0.71 ± 0.08, HD = 7.36 ± 2.72 mm, and MSD = 1.78 ± 0.66 mm, which had no significant difference with model performance at p values of 0.6, 0.52, and 0.88, respectively.
We developed a CNN-based model for auto-segmentation of pancreatic GTV in multi-parametric MRI. Model performance was comparable to expert radiation oncologists. This model provides a framework to incorporate multimodality images and daily MRI for GTV auto-segmentation in MRgOART.
Background
Clinical practice guidelines on uncomplicated birth provide clinical practice guidance and help to reduce unnecessary, non‐evidence‐based and potentially harmful intrapartum care ...practices. Little is known about the trustworthiness and consistency of these guidelines.
Objectives
To appraise guidelines relevant to uncomplicated birth, and summarise consensus and non‐consensus recommendations.
Search strategy
Eight literature databases and the websites of guideline development institutions and organisations of obstetricians, gynaecologists and midwives were searched from January 2008 to October 2018.
Selection criteria
Guidelines that: reported in Chinese or English; labelled guideline, or recommendation, or consensus, or practice parameter, or position paper/stand; with uncomplicated birth being the primary objectives or comprised chapter(s); and were the most recently published or updated versions.
Data collection and analysis
Two reviewers independently assessed guideline quality using the AGREE II instrument, and synthesised consensus and non‐consensus recommendations using the content analysis approach.
Main results
Eleven guidelines met the inclusion criteria. The WHO and NICE guidelines were deemed to have the highest methodological quality. Twenty‐three discrepant recommendations and 39 groups of unanimous recommendations (containing 113 individual ones) were identified, among which 14 recommendations including eating and drinking as desired, prophylactic uterotonics, routine amniotomy and episiotomy were included in five or more guidelines. Perineal massage, uterine massage, active or expectant management at the third stage and use of hands‐on or hands‐poised technique were identified as the main discrepant recommendations.
Conclusions
Two guidelines with higher methodological quality and key clinical guideline recommendations, including both consensus and non‐consensus ones, on uncomplicated birth were identified.
Tweetable
Clinical guidelines of uncomplicated birth agree and disagree on several key recommendations.
Tweetable
Clinical guidelines of uncomplicated birth agree and disagree on several key recommendations.
This study evaluates the prognostic significance of quantitative chimerism to monitor minimal residual disease and predict relapse in acute leukemia (AL) patients following allogeneic hematopoietic ...SCT (HSCT). The quantitative chimerism levels of 129 AL patients were measured using RQ-PCR based on 29 sequence polymorphisms. Receiver-operating characteristic curve indicated that the optimal cutoff point to predict an inevitable relapse was 1.0%, which results in 100.0% sensitivity and 79.6% specificity.The relapse rate of patients with chimerism >1.0% at 2 years was 55.0%, whereas that for patients with chimerism <1.0% was 0%(P=0.000). Quantitative chimerism >1.00% indicated a higher probability of relapse. Cox multivariate analysis indicated that quantitative chimerism >1.00% was associated with lower disease-free survival (hazard ratio (HR)=10.825; 95% confidence interval (CI) =4.704-24.912, P=0.000) and lower OS (HR=8.681; 95% CI=3.728-20.212, P=0.000). Patients (24/47 with quantitative chimerism >1.00%) who received preemptive modified DLI immunotherapy had significantly lower relapse rate (37.5%) than those (n=9) who did not (100%; P=0.001). Thus, quantitative chimerism is an independent prognostic factor that predicts clinical outcomes after HSCT and provides a guide for suitable interventions.
Sucrose is the main product of photosynthesis in plants, providing a rich carbon and energy source for the physiological growth and development of insects. In a previous study, we identified a novel ...sucrose hydrolase (SUH) in the larval midgut of moths. Intriguingly, there are two copies of Suh, namely Suh1 and Suh2, in several species of butterflies. However, the biochemical characteristics of SUHs in butterflies remain unclear. In this study, we found that this duplication and subsequent diversification produced two Suh genes in Papilio xuthus. These two PxSuh genes were significantly divergent in terms of their expression pattern and enzyme properties. PxSuh messenger RNA expression was highest during the larval stage, reduced in the prepupal and pupal stages and, for PxSuh1, slightly increased again in the adult. The observed levels of PxSuh2 were overall below those of PxSuh1 amongst the development stages examined. Compared with PxSUH2, which has maintained the original gene function of maltose hydrolysis, PxSUH1 exhibits substrate specificity for sucrose with an optimum enzyme activity occurring at an alkaline pH. The data show that PxSuh1 is evolutionarily adapted for effective functioning in an alkaline digestive system. Furthermore, we find that functional diversification of Suh facilitates P. xuthus to digestive carbohydrate of host plants. Thus, our findings offer new insights into the ecological and evolutionary adaptation of digestive enzymes in butterflies.
PDF
