The goal of this work is to perform a segmentation of the intimamedia thickness (IMT) of carotid arteries in view of computing various dynamical properties of that tissue, such as the elasticity ...distribution (elastogram). The echogenicity of a region of interest comprising the intima-media layers, the lumen, and the adventitia in an ultrasonic B -mode image is modeled by a mixture of three Nakagami distributions. In a first step, we compute the maximum a posteriori estimator of the proposed model, using the expectation maximization (EM) algorithm. We then compute the optimal segmentation based on the estimated distributions as well as a statistical prior for disease-free IMT using a variant of the exploration/selection (ES) algorithm. Convergence of the ES algorithm to the optimal solution is assured asymptotically and is independent of the initial solution. In particular, our method is well suited to a semi-automatic context that requires minimal manual initialization. Tests of the proposed method on 30 sequences of ultrasonic B -mode images of presumably disease-free control subjects are reported. They suggest that the semi-automatic segmentations obtained by the proposed method are within the variability of the manual segmentations of two experts.
Objectives
To compare the magnetic resonance imaging (MRI) and Doppler ultrasound (DUS) findings with the pathological findings of soft tissue vascular tumors (STVTs) according to the 2018 ISSVA ...(International Society for the Study of Vascular Anomalies) classification to differentiate vascular tumors from vascular malformations.
Methods
This retrospective study included patients with STVTs who underwent contrast-enhanced MRI and pathological analysis at our hospital between 2010 and 2020. The presumptive diagnosis based on the on-site imaging and histological analysis was compared with imaging and histological analysis conducted off-site utilizing the ISSVA criteria.
Results
This study included 31 patients with 31 vascular tumors located in the head and neck (
n
= 3), trunk (
n
= 2), and extremities (
n
= 26). The off-site pathological analysis confirmed benign vascular tumors in 54.8% of cases (non-involuting congenital hemangioma: 35.5%; epithelioid hemangioma: 13%; pyogenic granuloma: 3%; and spindle cell hemangioma: 3%). Based on the off-site histological analysis, 25.8% were reclassified as having a vascular malformation whereas three had other benign lesions. Only phleboliths were associated with a vascular malformation (
p
= 0.03). The concordance between off-site MRI and pathological findings was fair (
k
= 0.3902 (0.0531–0.7274)), whereas that between on-site and off-site pathological analyses was poor (
k
= −0.0949 (−0.4661 to 0.2763)).
Conclusion
Benign vascular tumors have non-specific imaging features on imaging with some overlap with atypical vascular malformations. Therefore, histological analysis is recommended. Imaging and pathological analyses should be performed in accordance with the ISSVA classification to minimize inter-observer discrepancies.
Critical relevance statement
Imaging features of benign vascular tumors on MRI are non-specific, leading to discrepancies with pathological findings and potential overlap with atypical vascular malformations. Imaging and histological analyses should be performed in accordance with ISSVA guidelines to improve patient management.
Key Points
The imaging features of benign vascular tumors are non-specific.
Histological analysis is recommended for soft tissue vascular tumors in adults.
Analyses of soft tissue vascular tumors should be performed in accordance with ISSVA guidelines.
Graphical Abstract
Abstract
Background
Social media has diverse applications for nursing education. Current literature focuses on how nursing faculty use social media in their courses and teaching; less is known about ...how and why nursing students use social media in support of their learning.
Objectives
The purpose of this study was to explore how nursing students use social media in their learning formally and informally.
Methods
This exploratory qualitative case study of a Canadian School of Nursing reports on the findings of interviews (
n
= 9) with nursing students to explore how they use social media in their learning. Data were analyzed using a combined deductive and inductive coding approach, using three cycles of coding to facilitate category identification.
Results and conclusions
The findings demonstrate that participants use social media for formal and informal learning and specifically, as a third space to support their learning outside of formal institutional structures. Social media plays a role in the learning activities of nursing students studying both face-to-face and by distance. Accordingly, social media use has implications for learning theory and course design, particularly regarding creating space for student learning communities.
KEY MESSAGE : Characterized novel mutations present at Ppo loci account for the substantial reduction of the total kernel PPO activity present in a putative null Ppo - A1 genetic background. Wheat ...(Triticum aestivum) polyphenol oxidase (PPO) contributes to the time-dependent discoloration of Asian noodles. Wheat contains multiple paralogous and orthologous Ppo genes, Ppo-A1, Ppo-D1, Ppo-A2, Ppo-D2, and Ppo-B2, expressed in wheat kernels. To date, wheat noodle color improvement efforts have focused on breeding cultivars containing Ppo-D1 and Ppo-A1 alleles conferring reduced PPO activity. A major impediment to wheat quality improvement is a lack of additional Ppo alleles conferring reduced kernel PPO. In this study, a previously reported very low PPO line, 07OR1074, was found to contain a novel allele at Ppo-A2 and null alleles at the Ppo-A1 and Ppo-D1 loci. To examine the impact of each mutation upon kernel PPO, populations were generated from crosses between 07OR1074 and the hard white spring wheat cultivars Choteau and Vida. Expression analysis using RNA-seq demonstrated no detectable Ppo-A1 transcripts in 07OR1074 while Ppo-D1 transcripts were present at less than 10 % of that seen in Choteau and Vida. Novel markers specific for the Ppo-D1 and Ppo-A2 mutations discovered in 07OR1074, along with the Ppo-A1 STS marker, were used to screen segregating populations. Evaluation of lines indicated a substantial genotypic effect on PPO with Ppo-A1 and Ppo-D1 alleles contributing significantly to total PPO in both populations. These results show that the novel mutations in Ppo-A1 and Ppo-D1 present in 07OR1074 are both important to lowering overall wheat seed PPO activity and may be useful to produce more desirable and marketable wheat-based products.
Wheat grain hardness is a major factor in the wheat end-product quality. Grain hardness in wheat affects such parameters as milling yield, starch damage and baking properties. A single locus ...determines whether wheat is hard or soft textured. This locus, termed Hardness ( Ha), resides on the short arm of chromosome 5D. Sequence alterations in the tryptophan-rich proteins puroindoline a and b (PINA and PINB) are inseparably linked to hard textured grain, but their role in endosperm texture has been controversial. Here, we show that the pinB-D1b alteration, common in hard textured wheats, can be complemented by the expression of wild-type pinB-D1a in transformed plants. Transgenic wheat seeds expressing wild-type pinB were soft in phenotype, having greatly increased friabilin levels, and greatly decreased kernel hardness and damaged starch. These results indicate that the pinB-D1b alteration is most likely the causative Ha mutation in the majority of hard wheats.
Fusarium head blight (FHB) is a fungal disease of wheat (Triticum aestivum L.) causing frequent economic losses to farmers under growing conditions of Eastern Canada. To assess risks associated with ...this disease and guide fungicide use decisions, many researchers from numerous countries have developed weather-based forecasting models. This work aims at evaluating which model produces the most accurate predictions of disease infection or deoxynivalenol (DON) content under climatic conditions occurring in Quebec. Spring wheat was grown during two seasons and winter wheat during one season at four experimental sites located in Quebec. Nine selected models for evaluation produced predictions of DON content (Canada and Italy), disease incidence (Argentina and Italy), and probability of epidemics (United States). Data from plots without fungicide (52 samples) were used to test the models listed above. Reliability of the selected forecasting models was evaluated with receiver operating characteristic (ROC) curve analysis. DON content (≥1 ppm) was the best crop damage indicator to differentiate epidemic (cases) and nonepidemic (controls) situations. Two American and the Argentinean forecasting models were more reliable than the others when the thresholds recommended in the literature were adjusted using the results for the ROC curve analyses. Those models are a good starting point for the implementation of an FHB forecasting system adapted to wheat production in Quebec.
Abstract
Shape memory materials have the ability to recover their original shape after a significant amount of deformation when they are subjected to certain stimuli, for instance, heat or magnetic ...fields. However, their performance is often limited by the energetics and geometry of the martensitic-austenitic phase transformation. Here, we report a unique shape memory behavior in CaFe
2
As
2
, which exhibits superelasticity with over 13% recoverable strain, over 3 GPa yield strength, repeatable stress–strain response even at the micrometer scale, and cryogenic linear shape memory effects near 50 K. These properties are acheived through a reversible uni-axial phase transformation mechanism, the tetragonal/orthorhombic-to-collapsed-tetragonal phase transformation. Our results offer the possibility of developing cryogenic linear actuation technologies with a high precision and high actuation power per unit volume for deep space exploration, and more broadly, suggest a mechanistic path to a class of shape memory materials, ThCr
2
Si
2
-structured intermetallic compounds.
Upregulation of starch biosynthesis in either source or sink tissue has been shown to increase yield under non-limiting resources. Previously we demonstrated that overexpression of AGPase in both ...leaf and seed tissue results in greater yield increases than overexpression in a single tissue alone. This study examines the link between starch biosynthesis, plant yield, and plant nutrition. Rice overexpressing AGPase in leaves and seeds (LS) was grown under four nutrition treatments and compared to wild type (WT) sister plants. In this study yield differences were most pronounced at low to mid nutrition levels. Greatest differences were observed at 0.075 g N L
−1
, where biomass and seed weight per plant were increased by 45% in LS plants. Alternatively leaf starch trended higher at mid to high nutrition, but was only significant at 0.1 g N L
−1
, where starch was 2.59 × higher compared to the WT. This was in contrast with photosynthetic rates. Rates were unchanged between LS and WT plants at 0.05 g N L
−1
nutrition, but significantly lower by 25% in LS plants at 0.1 g N L
−1
and 0.2 g N L
−1
nutrition. This study provides further insight into the complex interactions between starch biosynthesis, plant metabolism, and plant growth.
Background/Objectives
Elenbecestat, an oral BACE-1 inhibitor that has been shown to reduce Aβ levels in cerebrospinal fluid, was investigated in two global phase 3 studies in early AD. Here we report ...on differences observed in characteristics of APOE ε4 and amyloid positive subjects in the large screening cohort.
Design
Screening was performed in 5 sequential tiers over a maximum of 80 days, as part of placebo controlled, double blind phase 3 studies.
Setting
Subjects were evaluated at sites in 7 regions (29 countries).
Participants
Overall, 9758 subjects were screened.
Intervention
All screened subjects that were eligible received either placebo or 50 mg QID elenbecestat post randomisation.
Measurements
Gender, disease staging, APOE ε4 status, amyloid status, amyloid positron emission tomography (PET) standard uptake value ratio (SUVr) and amyloid PET Centiloid (CL) values were determined for screened subjects; by country and region.
Results
In this program, 44% of subjects were APOE ε4 positive. Frequency of females was similar in both APOE ε4 positive and negative groups. However, early mild AD subjects were slightly higher in the APOE ε4 positive group compared with the APOE ε4 negative group. 56% of subjects were amyloid positive. The mean age in the amyloid positive group was slightly higher than the amyloid negative group. The gender distribution was similar between amyloid groups. A lower number of mild cognitive impairment was observed in the amyloid positive group along with a higher number of early mild AD. APOE ε4 positive subjects were higher in amyloid positive group compared to the amyloid negative group. China had the lowest APOE ε4 and amyloid positivity rates with Western Europe and Oceania performing best. Subjects received florbetapir, florbetaben or flutemetamol amyloid PET tracer. Amyloid negative and positive subjects CL values were normally distributed around their respective means of 1.5 CL and 83 CL. However, there was an appreciable overlap in the 20–40 CL range.
Conclusions
In this large cohort of cognitively impaired subjects, subject demographics characteristics were comparable regardless of APOE genotype or amyloid positivity. APOE ε4 positivity and amyloid positivity varied by country and by geographical region.
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