| 471. |
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| 472. |
- Wang, Dan, et al.
(författare)
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On the phases of a semi-sectorial matrix and the essential phase of a Laplacian
- 2023
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Ingår i: Linear Algebra and its Applications. - : Elsevier BV. - 0024-3795 .- 1873-1856. ; 676, s. 441-458
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we extend the definition of phases of sectorial matrices to those of semi-sectorial matrices, which are possibly singular. Properties of the phases are also extended, including those of the Moore-Penrose generalized inverse, compressions and Schur complements, matrix sums and products. In particular, an interlacing relation is established between the phases of A+B and those of A and B combined. Also, a majorization relation is established between the phases of the nonzero eigenvalues of AB and the phases of the compressions of A and B, which leads to a generalized matrix small phase theorem. For the matrices which are not necessarily semi-sectorial, we define their (largest and smallest) essential phases via diagonal similarity transformation. An explicit expression for the essential phases of a Laplacian matrix of a directed graph is obtained.
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| 473. |
- Wang, Duo, et al.
(författare)
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Unraveling complex magnetism in two-dimensional FeS2
- 2021
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Ingår i: Physical Review B. - : American Physical Society. - 2469-9950 .- 2469-9969. ; 104:24
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Tidskriftsartikel (refereegranskat)abstract
- Atomically thin two-dimensional (2D) magnets have given rise to emergent phenomena due to magnetic exchange and spin-orbit coupling showing great promise for realizing ultrathin device structures. In this paper, we critically examine the magnetic properties of 2D FeS2, a non van der Waals magnet, which has been recently claimed to exhibit room-temperature ferromagnetism in the (111) orientation. Our ab initio study based on collinear density functional theory has revealed the ground state as an antiferromagnetic one with an ordering temperature of around 100 K along with a signature of spin-phonon coupling, which may trigger a ferromagnetic coupling via strain. Moreover, our calculations based on spin spirals indicate the possibility of noncollinear magnetic structures, which is also supported by Monte Carlo simulations based on ab initio magnetic exchange parameters. This opens up an excellent possibility to manipulate magnetic structures by the application of directional strain.
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| 474. |
- Wang, Guang, et al.
(författare)
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Controlling phase and rheological behaviours of hexagonal lyotropic liquid crystalline templates for nanostructural administration and retention
- 2022
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Ingår i: Journal of Colloid and Interface Science. - : Elsevier. - 0021-9797 .- 1095-7103. ; 607, s. 816-825
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Tidskriftsartikel (refereegranskat)abstract
- Introducing polymerizable monomers into a binary hexagonal lyotropic liquid crystalline (LLC) template is a straightforward way for retaining the nanostructure but will decrease attractive intra-and inter aggregate interactions. It is therefore crucial to understand the interfacial interactions at nanoscale after introducing the monomers but prior to polymerization. Herein, active species, poly (ethylene glycol) diacrylate (PEGDA) and 2-hydroxyethyl methacrylate (HEMA), were introduced into hexagonal LLC of dodecyl trimethylammonium bromide and water to explore the structural variables, dimensional stabil-ity, and dynamic property. At a proper volume ratio of PEGDA/HEMA (1/4), the system presents excellent homogeneity with a higher dimensional stability and lower dynamic property from rheological assess-ments, thereby achieving robust, free-standing, and transparent membranes after photo -polymerization. The unique property of the system also lies in the much lower order-disorder transition temperature (45 degrees C) that facilitates the reorientation of mesochannels. They are in contrast inaccessible for the ternary system only with PEGDA, though the nanostructure for both systems could be retained. An insight into subtle variations in these parameters allows us to prepare a polymerizable template possess-ing higher dimensional stability and suitable flexibility via molecular design, thereby enabling simulta-neous structural alignment and retention for the development of functional nanomaterials. (c) 2021 Elsevier Inc. All rights reserved.
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| 475. |
- Wang, Guan, et al.
(författare)
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Transient analyses for China initiative Accelerator Driven System using the extended BELLA code
- 2023
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Ingår i: Annals of Nuclear Energy. - : Elsevier BV. - 0306-4549 .- 1873-2100. ; 190
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Tidskriftsartikel (refereegranskat)abstract
- China initiative Accelerator Driven System (CiADS) is a 10 MW lead-bismuth eutectic (LBE) cooled subcritical reactor loaded with UO2 fuels in the first phase, which is designed to demonstrate the engineering feasibility of the ADS concept. The transient analyses were performed to show the safety potential and dynamic characteristics of the CiADS subcritical reactor using the extended BELLA code. Typical scenarios, such as beam-trip transients, unprotected beam overpower (UBOP), unprotected and protected loss of flow (ULOF and PLOF), unprotected and protected loss of heat sink (ULOHS and PLOHS) and self-defined station blackout (SBO), were analyzed and simulated. The results indicate that, as a low-power reactor, the CiADS subcritical reactor has a large margin to avoid severe damage in the core. Short-term cladding failure caused by thermal fatigue under frequent beam trips may not happen since the variations of temperatures are relatively small. However, accelerated LBE corrosion combined with accumulated creep tends to be a risk under ULOF and ULOHS.
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| 476. |
- Wang, Gang, et al.
(författare)
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US2Mask : Image-to-mask generation learning via a conditional GAN for cardiac ultrasound image segmentation
- 2024
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Ingår i: Computers in Biology and Medicine. - Oxford : Elsevier. - 0010-4825 .- 1879-0534. ; 172, s. 1-13
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Tidskriftsartikel (refereegranskat)abstract
- Cardiac ultrasound (US) image segmentation is vital for evaluating clinical indices, but it often demands a large dataset and expert annotations, resulting in high costs for deep learning algorithms. To address this, our study presents a framework utilizing artificial intelligence generation technology to produce multi-class RGB masks for cardiac US image segmentation. The proposed approach directly performs semantic segmentation of the heart's main structures in US images from various scanning modes. Additionally, we introduce a novel learning approach based on conditional generative adversarial networks (CGAN) for cardiac US image segmentation, incorporating a conditional input and paired RGB masks. Experimental results from three cardiac US image datasets with diverse scan modes demonstrate that our approach outperforms several state-of-the-art models, showcasing improvements in five commonly used segmentation metrics, with lower noise sensitivity. Source code is available at https://github.com/energy588/US2mask. © 2024 Elsevier Ltd
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| 477. |
- Wang, Hong, et al.
(författare)
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Real-time tracking of mitochondrial dynamics by a dual-sensitive probe
- 2020
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Ingår i: Sensors and actuators. B, Chemical. - : Elsevier. - 0925-4005 .- 1873-3077. ; 320
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Tidskriftsartikel (refereegranskat)abstract
- Tracking of mitochondrial dynamic processes including their morphology, biogenesis and elimination is of significance to deeply understand mitochondrial physiology and related diseases, which requires simultaneous and discriminative labeling of both mitochondria themselves and correlated downstream organelles. However, the combination of multiple fluorescent probes will bring the large invasive effect that seriously impacts the normal physiological processes of mitochondria within live cells. To address this issue, we herein construct a single molecular probe through the combination of two pH-sensitive fluorogens, hydroxyl-coumarin and rhodamine B, enabling the detection of intracellular microenvironmental pH variations. Importantly, the as-synthesized probe not only accumulates into mitochondria, indicated by cyan emission from hydroxyl-coumarin but also can be delivered to the downstream acidic autolysosomes upon the occurrence of mitophagy, indicated by red emission from rhodamine B. Taking advantage of a two-channel confocal microscopy strategy, we have achieved to real-time track the processes of mitochondrial replication, merge and autophagy.
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| 478. |
- Wang, Hui-Xin, et al.
(författare)
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Association of lifelong exposure to cognitive reserve-enhancing factors with dementia risk : A community-based cohort study
- 2017
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Ingår i: PLoS Medicine. - : Public Library of Science (PLoS). - 1549-1277 .- 1549-1676. ; 14:3
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Variation in the clinical manifestation of dementia has been associated with differences in cognitive reserve, although less is known about the cumulative effects of exposure to cognitive reserve factors over the life course. We examined the association of cognitive reserve-related factors over the lifespan with the risk of dementia in a community-based cohort of older adults.METHODS AND FINDINGS: Information on early-life education, socioeconomic status, work complexity at age 20, midlife occupation attainment, and late-life leisure activities was collected in a cohort of dementia-free community dwellers aged 75+ y residing in the Kungsholmen district of Stockholm, Sweden, in 1987-1989. The cohort was followed up to 9 y (until 1996) to detect incident dementia cases. To exclude preclinical phases of disease, participants who developed dementia at the first follow-up examination 3 y after the baseline were excluded (n = 602 after exclusions). Structural equation modelling was used to generate latent factors of cognitive reserve from three periods over the life course: early (before 20 y), adulthood (around 30-55 y), and late life (75 y and older). The correlation between early- and adult-life latent factors was strong (γ = 0.9), whereas early-late (γ = 0.27) and adult-late (γ = 0.16) latent factor correlations were weak. One hundred forty-eight participants developed dementia during follow-up, and 454 remained dementia-free. The relative risk (RR) of dementia was estimated using Cox models with life-course cognitive reserve-enhancing factors modelled separately and simultaneously to assess direct and indirect effects. The analysis was repeated among carriers and noncarriers of the apolipoprotein E (APOE) ε4 allele. A reduced risk of dementia was associated with early- (RR 0.57; 95% CI 0.36-0.90), adult- (RR 0.60; 95% CI 0.42-0.87), and late-life (RR 0.52; 95% CI 0.37-0.73) reserve-enhancing latent factors in separate multivariable Cox models. In a mutually adjusted model, which may have been imprecisely estimated because of strong correlation between early- and adult-life factors, the late-life factor preserved its association (RR 0.65; 95% CI 0.45-0.94), whereas the effect of midlife (RR 0.73; 95% CI 0.50-1.06) and early-life factors (RR 0.76; 95% CI 0.47-1.23) on the risk of dementia was attenuated. The risk declined progressively with cumulative exposure to reserve-enhancing latent factors, and having high scores on cognitive reserve-enhancing composite factors in all three periods over the life course was associated with the lowest risk of dementia (RR 0.40; 95% CI 0.20-0.81). Similar associations were detected among APOE ε4 allele carriers and noncarriers. Limitations include measurement error and nonresponse, with both biases likely favouring the null. Strong correlation between early- and adult-life latent factors may have led to a loss in precision when estimating mutually adjusted effects of all periods.CONCLUSIONS: In this study, cumulative exposure to reserve-enhancing factors over the lifespan was associated with reduced risk of dementia in late life, even among individuals with genetic predisposition.
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| 479. |
- Wang, Hui-Xin, et al.
(författare)
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Dementia
- 2012
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Ingår i: Handbook of Clinical Gender Medicine. - Basel : Karger. - 9783805599290 ; , s. 495-503
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Bokkapitel (refereegranskat)abstract
- Dementia is the most common mental disorder contributing greatly to disability, institutionalization, and shorter survival among the older population of both genders. Both the prevalence and incidence of dementia are higher in women than in men after the age of 80. Men and women have different profiles concerning risk factors and outcomes of dementia, with most of them favoring men. Epidemiological and experimental studies have indicated that estrogen would protect against dementia and Alzheimer's disease. However, evidence is still lacking that hormonal replacement therapy could protect against dementia. The role of male sex hormones for dementia risk has been less investigated. Although the causes of gender differences remain poorly understood, awareness of these differences may help identify persons at risk for dementia, affect its prognosis, and have implications for disease prevention.
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| 480. |
- Wang, Hui-Xin, et al.
(författare)
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Education halves the risk of dementia due to apolipoprotein ε4 allele : a collaborative study from the Swedish brain power initiative
- 2012
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Ingår i: Neurobiology of Aging. - : Elsevier BV. - 0197-4580 .- 1558-1497. ; 33:5, s. 1007.e1-1007.e7
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Tidskriftsartikel (refereegranskat)abstract
- A number of studies have explored the relationships of apolipoprotein E (APOE) genotype and education with dementia over the last decade. However, observations concerning the possible modifying effect of education on the APOE-dementia association are limited. The objective of this study was to test the hypothesis that education may decrease the risk of APOE ε4 on dementia. Pooled data from 3 major population-based studies in Northern Europe were used in this study, with a total of 3436 participants aged 65 and older derived from the Kungsholmen project and the Gothenburg Birth Cohort studies in Sweden, and the Cardiovascular Risk Factors, Aging and Dementia (CAIDE) project in Finland. The main outcome measure was dementia, which was diagnosed in 219 persons according to standard criteria. APOE ε4 was associated with increased risk of dementia independent of the effect of education (odds ratio [OR], 2.5; 95% confidence interval [CI], 1.9-3.4 for 1 ε4 carrier and OR, 3.7; 95% CI, 1.8-7.2 for 2 ε4 carriers). High education (8 years and more) was related to a lower dementia risk (OR, 0.5; 95% CI, 0.3-0.6). An interaction between education and APOE ε4 was observed. Compared with those with less education and no ε4, the odds of dementia among persons with low education who carried any ε4 allele was 2.7 (95% CI, 1.9-3.9), and 1.2 (0.7-1.8) if they had higher education. This study suggests that genetic (APOE ε4) and environmental (education) factors are not only independently but also interactively related to dementia risk and that high education may buffer the negative effect of APOE ε4 on dementia occurrence.
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