| 1. |
- Han, Xiaolei, et al.
(författare)
-
Accelerometer-assessed sedentary behaviour among Chinese rural older adults : Patterns and associations with physical function
- 2022
-
Ingår i: Journal of Sports Sciences. - : Informa UK Limited. - 0264-0414 .- 1466-447X. ; 40:17, s. 1940-1949
-
Tidskriftsartikel (refereegranskat)abstract
- Sedentary behaviour is associated with a range of adverse health conditions. Population-based studies have rarely examined the distribution and associated factors of accelerometer-measured sedentary behaviour patterns in rural-dwelling older adults. This population-based study included 2096 rural-dwelling older adults (age ≥60 years; 59.0% women) derived from baseline participants of the MIND-China Study. Total sedentary time and patterns (e.g., uninterrupted bouts and breaks) were derived from the hip-worn accelerometers for 7 days. Physical function was assessed using the Short Physical Performance Battery test. Data were analysed using general linear models. Overall, participants spent 58.8% of daily waking time in sedentary behaviour, with nearly half of sedentary time being accumulated through sedentary bouts of 30+ minutes. Men spent more total and accumulated sedentary time than women in each sedentary bout duration, while women had more daily 1+ minute sedentary bouts than men (all P < 0.001). Controlling for moderate-to-vigorous physical activity and other confounders, more prolonged sedentary time and fewer breaks were significantly associated with poor physical function, balance, lower limb strength, and walking speed (all P < 0.001). In older adults living in rural communities, prolonged sedentary behaviour and less frequent breaks are associated with poor physical function.
|
|
| 2. |
- Han, Xiaolei, et al.
(författare)
-
KIBRA regulates amyloid β metabolism by controlling extracellular vesicles secretion
- 2022
-
Ingår i: EBioMedicine. - : Elsevier BV. - 2352-3964. ; 78
-
Tidskriftsartikel (refereegranskat)abstract
- Background Previous research has revealed that KIBRA controls secretion of extracellular vesicles (EVs) by inhibiting the proteasomal degradation of Rab27a and EVs play an important role in amyloid β (Aβ) metabolism and transmission during Alzheimer's disease (AD) pathogenesis. Here, we further test the hypothesis that KIBRA regulates Aβ metabolism via the endosomal-lysosomal system.Methods We generated KIBRA knockout mice on a 5XFAD background and KIBRA knockdown cells in murine HT22 cells with stably overexpressing APP. Various forms of Aβ and quantification of EVs were analyzed by biochemical methods and nanoparticle tracking analysis, respectively. Multivesicular bodies (MVBs) were visualized by electron microscopy and confocal fluorescent microscopy. In a population-based cohort (n = 1419), KIBRA genotypes and plasma Aβ levels were analyzed using multiple-PCR amplification and Simoa, respectively.Findings Multiple forms of Aβ were dramatically attenuated in KIBRA knockout mouse brain, including monomers, oligomers, and extracellular deposition, but KIBRA knockout had no effect on intraneuronal APP C-terminal fragment β (APP-CTFβ)/Aβ levels. KIBRA depletion also decreased APP-CTFβ/Aβ-associated EVs secretion and subsequently enhanced MVBs number. Furthermore, we found that excessive accumulation of MVBs harboring APP-CTFβ/Aβ promoted the MVBs-lysosome fusion for degradation and inhibition of lysosomal function rescued secretion of APP-CTFβ/Aβ-associated EVs. More importantly, whole exon sequencing of KIBRA in a large population-based cohort identified the association of KIBRA rs28421695 polymorphism with plasma Aβ levels.Interpretation These results demonstrate that KIBRA regulates Aβ metabolism via controlling the secretion of APP-CTFβ/Aβ-associated EVs.
|
|
| 3. |
- Wang, Chaoqun, et al.
(författare)
-
Associations of Cardiac Ventricular Repolarization with Serum Adhesion Molecules and Cognitive Function in Older Adults : The MIND-China Study
- 2023
-
Ingår i: Journal of Alzheimer's Disease. - 1387-2877 .- 1875-8908. ; 92:1, s. 273-283
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Emerging evidence has linked electrocardiographic parameters with serum adhesion molecules and cognition; however, their interrelationship has not been explored.Objective: We sought to investigate the associations of ventricular depolarization and repolarization intervals with serum adhesion molecules and cognitive function among rural-dwelling older adults.Methods: This population-based study engaged 4,886 dementia-free participants (age ≥60 years, 56.2% women) in the baseline examination (March-September 2018) of MIND-China. Of these, serum intercellular and vascular adhesion molecules (ICAM-1 and VCAM-1) were measured in 1591 persons. We used a neuropsychological test battery to assess cognitive function. Resting heart rate, QT, JT intervals, and QRS duration were assessed with electrocardiogram. Data were analyzed using general linear models adjusting for multiple confounders.Results: Longer JT interval was significantly associated with lower z-scores of global cognition (multivariable-adjusted β= –0.035; 95% confidence interval = –0.055, –0.015), verbal fluency (–0.035; –0.063, –0.007), attention (–0.037; –0.065, –0.010), and executive function (–0.044; –0.072, –0.015), but not with memory function (–0.023; –0.054, 0.009). There were similar association patterns of QT interval with cognitive functions. In the serum biomarker subsample, longer JT and QT intervals remained significantly associated with poorer executive function and higher serum adhesion molecules. We detected statistical interactions of JT interval with adhesion molecules (pinteraction <0.05), such that longer JT interval was significantly associated with a lower executive function z-score only among individuals with higher serum ICAM-1 and VCAM-1.Conclusion: Longer ventricular depolarization and repolarization intervals are associated with worse cognitive function in older adults and vascular endothelial dysfunction may play a part in the associations.
|
|
| 4. |
- Wang, Chaoqun, et al.
(författare)
-
Associations of WWC1 variants with Alzheimer?s disease and vascular dementia among rural older adults in China : A population-based study
- 2023
-
Ingår i: Neurobiology of Aging. - : Elsevier BV. - 0197-4580 .- 1558-1497. ; 125, s. 109-114
-
Tidskriftsartikel (refereegranskat)abstract
- We sought to examine the associations of common WWC1 variants with Alzheimer's disease (AD) and vascular dementia (VaD) among rural-dwelling older adults in China. This population-based study used data from the baseline assessments (March –September 2018) of MIND-China. AD and VaD were diagnosed following the international criteria. Of the 5455 participants (age≥60 years, 57.27% women), 182 were diagnosed with AD and 88 with VaD. Logistic regression analysis suggested that WWC1 rs17070145 C allele (vs. T) was associated with multivariable-adjusted odds ratio of 1.23 (95% confidence interval 0.96–1.58) for AD, and that CC genotype (vs. TT) was associated with multivariable-adjusted odds ratio of 2.19(1.10–4.39) for VaD, but the association with VaD became non-significant when further adjusting for stroke history. Furthermore, exonic SNPs rs3822660 and rs3822659 were in strong linkage disequilibrium (LD) with rs17070145 (D’ = 0.88). These results suggest that the strong LD between rs17070145 and 2 exonic SNPs may explain the association of WWC1 rs17070145 C allele with AD and that stroke may partly explain the association of WWC1 rs17070145 CC genotype with VaD.
|
|
| 5. |
- Wang, Yongxiang, et al.
(författare)
-
Nonalcoholic fatty liver disease, serum cytokines, and dementia among rural-dwelling older adults in China : A population-based study
- 2022
-
Ingår i: European Journal of Neurology. - : Wiley. - 1351-5101 .- 1468-1331. ; 29:9, s. 2612-2621
-
Tidskriftsartikel (refereegranskat)abstract
- Background and purpose: Little is known about whether nonalcoholic fatty liver disease (NAFLD) is associated with dementia or the role of serum proinflammatory cytokines in the association. We aimed to investigate the interrelationships of NAFLD, serum cytokines, and dementia among rural-dwelling older adults.Methods: This population-based cross-sectional study included 5129 participants (aged ≥60 years; 61.79% women) who were living in rural communities and examined in March 2018–September 2018. NAFLD was defined through transabdominal ultrasound examination in the absence of hepatitis B or excessive alcohol consumption. Serum cytokines were measured in a subsample (n = 1686). Dementia, Alzheimer disease (AD), and vascular dementia (VaD) were diagnosed following international criteria. Data were analyzed with logistic regression and mediation models.Results: Of the 5129 participants, 455 (8.87%) were detected with moderate-to-severe NAFLD, and 292 (5.69%) were diagnosed with dementia (188 with AD and 96 with VaD). The multivariable adjusted odds ratios associated with moderate-to-severe (vs. no-to-mild) NAFLD were 2.22 (95% confidence interval [CI] = 1.41–3.49) for all-cause dementia, 1.88 (95% CI = 1.01–3.50) for AD, and 2.62 (95% CI = 1.33–5.17) for VaD. In the cytokine subsample, controlling for multiple potential confounders, moderate-to-severe NAFLD was significantly associated with higher levels of serum monocyte chemotactic protein-1, interleukin-17A, interleukin-6 (IL-6), interleukin-8, and tumor necrosis factor-α (P < 0.05). The mediation analysis showed that IL-6 mediated 12.56% of the association between NAFLD and VaD.Conclusions: Moderate-to-severe nonalcoholic fatty liver disease is associated with dementia and AD, especially with VaD, among rural-dwelling Chinese older adults, in which the association with VaD is partly mediated by serum inflammatory cytokines.
|
|
| 6. |
- Wang, Yongxiang, et al.
(författare)
-
Objectively-measured movement behaviors, systemic low-grade inflammation, and plasma neurofilament light chain in older adults : a population-based study
- 2023
-
Ingår i: Immunity & Ageing. - 1742-4933. ; 20:1
-
Tidskriftsartikel (refereegranskat)abstract
- BackgroundEvidence has linked self-reported sedentary behavior (SB) and physical activity (PA) with cognitive impairment; however, the underlying mechanisms are poorly understood. We examined the associations of the accelerometer-measured movement behaviors with plasma neurofilament light chain (NfL) among older adults and the role of systemic low-grade inflammation in the associations.ResultsThis population-based study included 1,029 dementia-free older adults (age & GE; 60 years, range 60-88 years; 59.48% women) who undertook the ActiGraph substudy (March 2018-December 2020) in MIND-China. There were nonlinear relationships of daily SB and PA time with plasma NfL concentration, such that more daily SB time or less time spent in daily light-intensity physical activity (LPA) and moderate-to-vigorous-intensity physical activity (MVPA) was significantly associated with increased plasma NfL only when SB time & GE; 8.00 h/day or LPA time < 5.00 h/day or MVPA time < 2.00 h/day. Furthermore, more daily SB time or less daily LPA and MVPA time was significantly associated with higher serum low-grade inflammation score, a composite measure generated from serum IL-6, IL-8, TNF-& alpha;, and ICAM-1 (P < 0.05). Finally, low-grade inflammation score accounted for 14.5% to 17.8% of the associations between movement behaviors and plasma NfL.ConclusionsMore daily SB and less PA time are associated with neurodegeneration and systemic low-grade inflammation in older adults. The association of movement behaviors with neurodegeneration is partially mediated by low-grade inflammation.
|
|
| 7. |
- Han, Xiaolei, et al.
(författare)
-
Accelerometer-measured sedentary behavior patterns, brain structure, and cognitive function in dementia-free older adults : a population-based study
- 2023
-
Ingår i: Journal of Alzheimer's Disease. - : IOS Press. - 1387-2877 .- 1875-8908. ; 96:2, s. 657-668
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Sedentary behavior is associated with cognitive impairment, but the neuropathological mechanisms underlying their associations are poorly understood.Objective: To investigate the associations of accelerometer-measured sedentary behavior patterns with brain structure and cognition, and further to explore the potential mechanisms.Methods: This community-based study included 2,019 older adults (age≥60 years, 59% women) without dementia derived from participants in the baseline examination of MIND-China (2018-2020). We assessed sedentary parameters using an accelerometer and cognitive function using a neuropsychological test battery. Structural brain markers were assessed on the structural brain MRI scans in a subsample (n = 1,009). Data were analyzed using the general linear, isotemporal substitution, and mediation models.Results: In the total sample (n = 2,019), adjusting for multiple covariates and moderate-to-vigorous-intensity physical activity, longer mean sedentary bout duration was linearly related with lower z-scores of global cognition, verbal fluency, and memory (ptrend < 0.05), whereas greater total sedentary time was linearly associated with lower z-scores of global cognition, verbal fluency, and memory only among individuals with long sedentary time (>10 h/day) (ptrend < 0.05); Breaking up sedentary time with same amount of light-intensity physical activity was significantly associated with higher verbal fluency and memory z-scores (p < 0.05). In the MRI subsample (n = 1,009), separately entering structural brain MRI markers into the mediation models substantially attenuated the associations of mean sedentary bout duration with global cognition, verbal fluency, and memory z-scores.Conclusion: Prolonged uninterrupted sedentary time is associated with poor global cognition, memory, and verbal fluency among rural older adults, and structural brain markers could partially mediate the association.
|
|
| 8. |
- Wang, Xiaojie, et al.
(författare)
-
A City-Wide Real-Time Traffic Management System : Enabling Crowdsensing in Social Internet of Vehicles
- 2018
-
Ingår i: IEEE Communications Magazine. - 0163-6804 .- 1558-1896. ; 56:9, s. 19-25
-
Tidskriftsartikel (refereegranskat)abstract
- As an emerging platform based on ITS, SIoV is promising for applications of traffic management and road safety in smart cities. However, the end-to-end delay is large in store-carry-and-forward-based vehicular networks, which has become the main obstacle for the implementation of large-scale SIoV. With the extensive applications of mobile devices, crowdsensing is promising to enable real-time content dissemination in a city-wide traffic management system. This article first provides an overview of several promising research areas for traffic management in SIoV. Given the significance of traffic management in urban areas, we investigate a crowdsensing-based framework to provide timely response for traffic management in heterogeneous SIoV. The participant vehicles based on D2D communications integrate trajectory and topology information to dynamically regulate their social behaviors according to network conditions. A real-world taxi trajectory analysis-based performance evaluation is provided to demonstrate the effectiveness of the designed framework. Furthermore, we discuss several future research challenges before concluding our work.
|
|
| 9. |
- Wang, Xiangjian, et al.
(författare)
-
Large electrical strain in lead-free K0.5Na0.5NbO3-based ceramics by heterovalent doping
- 2023
-
Ingår i: Journal of Materiomics. - : Elsevier. - 2352-8478 .- 2352-8486. ; 9:5, s. 959-970
-
Tidskriftsartikel (refereegranskat)abstract
- Heterovalent doped (K0.48-0.07xNa0.52-0.43xBi0.5x)(Nb0.95-0.95xSb0.05-0.05xZrx)O3 ceramics were fabricated using conventional solid-state reaction. Then, the phase structures, dielectric, ferroelectric, and electric-strain properties were investigated. The compositions were tuned to be located at polymorphic phase boundary with increasing heterovalent Bi3+ and Zr4+ doping levels. A large strain of 0.19% was obtained at relatively low electric fields of 30 kV/cm in the composition of x = 0.04. The normalized large-signal d33* values were approximately 633 pm/V under a low driving electric field of 30 kV/cm, which were comparable or larger than the values reported for other lead-free families. The large strains obtained can be attributed to the formation of nanodomains and high-density domain walls, which were confirmed by the observations of domain morphology using transmission electron microscopy (TEM) technique. Excellent temperature stability of the strain properties of the x = 0.04 sample could be ascribed to the sluggish behaviour for the local structural heterogeneity in heterovalent-ion doped KNN ceramic. Theoretical simulations revealed that the Zr4+ produce the local stress at the BO6 octahedra and Bi3+ could yield off-centering of AO12 ployhedron due to the nature of Bi 6s lone pair electrons, which induced lattice expansion and local distortions in the sample. The local displacements are strongly anisotropic in heterovalent-ion doped system. It is believed that random local fields exist in these compositions owing to the eixstence of charge distribution. Such heterovalent doping of Bi3+ and Zr4+ could destory simutiously the orthorhombic symmetry and the short-range ferroelecctric order, leading to the formation of complex nanodomains and local structral hetergenenity. Heterovalent doping may, therefore, offer a new avenve to design novel K0.5Na0.5NbO3 (KNN) -based materials for their mutifunctional applications.
|
|
| 10. |
- Anton, Rikard, et al.
(författare)
-
Full discretisation of semi-linear stochastic wave equations driven by multiplicative noise
- 2015
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- A fully discrete approximation of the semi-linear stochastic wave equation driven by multiplicative noise is presented. A standard linear finite element approximation is used in space and a stochastic trigonometric method for the temporal approximation. This explicit time integrator allows for mean-square error bounds indepen- dent of the space discretisation and thus do not suffer from a step size restriction as in the often used Störmer-Verlet- leap-frog scheme. Furthermore, it satisfies an almost trace formula (i. e., a linear drift of the expected value of the energy of the problem). Numerical experiments are presented and confirm the theoretical results.
|
|
| 11. |
- Anton, Rikard, et al.
(författare)
-
Full discretization of semilinear stochastic wave equations driven by multiplicative noise
- 2016
-
Ingår i: SIAM Journal on Numerical Analysis. - 0036-1429 .- 1095-7170. ; 54:2, s. 1093-1119
-
Tidskriftsartikel (refereegranskat)abstract
- A fully discrete approximation of the semilinear stochastic wave equation driven by multiplicative noise is presented. A standard linear finite element approximation is used in space, and a stochastic trigonometric method is used for the temporal approximation. This explicit time integrator allows for mean-square error bounds independent of the space discretization and thus does not suffer from a step size restriction as in the often used Stormer-Verlet leapfrog scheme. Furthermore, it satisfies an almost trace formula (i.e., a linear drift of the expected value of the energy of the problem). Numerical experiments are presented and confirm the theoretical results.
|
|
| 12. |
- Jiang, Heng, et al.
(författare)
-
Measuring and preventing alcohol use and related harm among young people in Asian countries : a thematic review
- 2018
-
Ingår i: Global Health Research and Policy. - : Springer Science and Business Media LLC. - 2397-0642. ; 3:14
-
Tidskriftsartikel (refereegranskat)abstract
- Background: The paper reviews alcohol consumption patterns and alcohol-related social and health issues among 15-29-year old young people in Asian countries, and discusses strategies for preventing and controlling alcohol use and related harms.Methods: We searched Google Scholar, PubMed, and Web of Science for reports, reviews and journal articles published in English between 1st Jan 1990 and 31st August 2016.Results: Forty-one reports, reviews and journal papers were identified and included in the final review. The current drinking levels and prevalence among young people are markedly different between eight included Asian countries, ranging from 4.2% in Malaysia to 49.3% in China. In a majority of the selected Asian countries, over 15% of total deaths among young men and 6% among young women aged 15-29 years are attributable to alcohol use. Alcohol use among young people is associated with a number of harms, including stress, family violence, injuries, suicide, and sexual and other risky behaviours. Alcohol policies, such as controlling sales, social supply and marketing, setting up/raising a legal drinking age, adding health warning labels on alcohol containers, and developing a surveillance system to monitor drinking pattern and risky drinking behaviour, could be potential means to reduce harmful use of alcohol and related harm among young people in Asia.Conclusions: The review reveals that drinking patterns and behaviours vary across eight selected Asian countries due to culture, policies and regional variations. The research evidence holds substantial policy implications for harm reduction on alcohol drinking among young people in Asian countries -- especially for China, which has almost no alcohol control policies at present.
|
|
| 13. |
|
|
| 14. |
- Li, Ruihuan, et al.
(författare)
-
Effects of Cr and W additions on the stability and migration of He in bcc Fe : A first-principles study
- 2016
-
Ingår i: Computational materials science. - : Elsevier. - 0927-0256 .- 1879-0801. ; 123, s. 85-92
-
Tidskriftsartikel (refereegranskat)abstract
- Density functional theory calculations have been performed to study the effects of alloying Cr and W on the stability and diffusivity of interstitial He impurity in body-centered cubic (bcc) Fe host lattice. The interaction between two close Cr/W atoms is repulsive. The relative stable position for an interstitial He remains the tetrahedral interstitial site in the presence Cr. Energetically, He prefers to locate far away from W inside Fe host lattice due to the strong repulsive interaction between He and W. On the other hand, the He migration barrier becomes lower in the presence of Cr (0.026 eV) and W(0.049 eV), as compared to 0.059 eV for pure Fe. Addition of Cr is benefit for He self-trapping, while W is against. The effective diffusivity of He decreases with increasing Cr and W concentrations. Moreover, the additions of Cr and W slightly hinder He being trapped by monovacancy.
|
|
| 15. |
- Li, Xiaojie, et al.
(författare)
-
Ab initio calculations of mechanical properties of bcc W-Re-Os random alloys : effects of transmutation of W
- 2016
-
Ingår i: Journal of Physics. - : Institute of Physics Publishing (IOPP). - 0953-8984 .- 1361-648X. ; 28:29
-
Tidskriftsartikel (refereegranskat)abstract
- To examine the effect of neutron transmutation on tungsten as the first wall material of fusion reactors, the elastic properties of W1-x-yRexOsy (0 <= x, y <= 6%) random alloys in body centered cubic (bcc) structure are investigated systematically using the all-electron exact muffin-tin orbitals (EMTO) method in combination with the coherent-potential approximation (CPA). The calculated lattice constant and elastic properties of pure W are consistent with available experiments. Both Os and Re additions reduce the lattice constant and increase the bulk modulus of W, with Os having the stronger effect. The polycrystalline shear modulus, Young's modulus and the Debye temperature increase (decrease) with the addition of Re (Os). Except for C-11, the other elastic parameters including C-12, C-44, Cauchy pressure, Poisson ratio, B/G, increase as a function of Re and Os concentration. The variations of the latter three parameters and the trend in the ratio of cleavage energy to shear modulus for the most dominant slip system indicate that the ductility of the alloy enhances with increasing Re and Os content. The calculated elastic anisotropy of bcc W slightly increases with the concentration of both alloying elements. The estimated melting temperatures of the W-Re-Os alloy suggest that Re or Os addition will reduce the melting temperature of pure W solid. The classical Labusch-Nabarro model for solid-solution hardening predicts larger strengthening effects in W1-yOsy than in W1-xRex. A strong correlation between C' and the fcc-bcc structural energy difference for W1-x-yRexOsy is revealed demonstrating that canonical band structure dictates the alloying effect on C'. The structural energy difference is exploited to estimate the alloying effect on the ideal tensile strength in the [0 0 1] direction.
|
|
| 16. |
- Radeva, Nedyalka, et al.
(författare)
-
Active Site Mapping of an Aspartic Protease by Multiple Fragment Crystal Structures : Versatile Warheads to Address a Catalytic Dyad
- 2016
-
Ingår i: Journal of Medicinal Chemistry. - : American Chemical Society (ACS). - 0022-2623 .- 1520-4804. ; 59:21, s. 9743-9759
-
Tidskriftsartikel (refereegranskat)abstract
- Crystallography is frequently used as follow-up method to validate hits identified by biophysical screening cascades. The capacity of crystallography to directly screen fragment libraries is often underestimated, due to its supposed low-throughput and need for high-quality crystals. We applied crystallographic fragment screening to map the protein-binding site of the aspartic protease endothiapepsin by individual soaking experiments. Here, we report on 41 fragments binding to the catalytic dyad and adjacent specificity pockets. The analysis identifies already known warheads but also reveals hydrazide, pyrazole, or carboxylic acid fragments as novel functional groups binding to the dyad. A remarkable swapping of the S1 and S1′ pocket between structurally related fragments is explained by either steric demand, required displacement of a well-bound water molecule, or changes of trigonal-planar to tetrahedral geometry of an oxygen functional group in a side chain. Some warheads simultaneously occupying both S1 and S1′ are promising starting points for fragment-growing strategies.
|
|
| 17. |
- Schiebel, Johannes, et al.
(författare)
-
High-Throughput Crystallography : Reliable and Efficient Identification of Fragment Hits
- 2016
-
Ingår i: Structure. - : Elsevier BV. - 0969-2126. ; 24:8, s. 409-1398
-
Tidskriftsartikel (refereegranskat)abstract
- Today the identification of lead structures for drug development often starts from small fragment-like molecules raising the chances to find compounds that successfully pass clinical trials. At the heart of the screening for fragments binding to a specific target, crystallography delivers structural information essential for subsequent drug design. While it is common to search for bound ligands in electron densities calculated directly after an initial refinement cycle, we raise the important question whether this strategy is viable for fragments characterized by low affinities. Here, we describe and provide a collection of high-quality diffraction data obtained from 364 protein crystals treated with diverse fragments. Subsequent data analysis showed that ∼25% of all hits would have been missed without further refining the resulting structures. To enable fast and reliable hit identification, we have designed an automated refinement pipeline that will inspire the development of optimized tools facilitating the successful application of fragment-based methods.
|
|
| 18. |
- Sun, Haonan, et al.
(författare)
-
Large energy storage density in BiFeO3-BaTiO3-AgNbO3 lead-free relaxor ceramics
- 2020
-
Ingår i: Journal of the European Ceramic Society. - : Elsevier. - 0955-2219 .- 1873-619X. ; 40:8, s. 2929-2935
-
Tidskriftsartikel (refereegranskat)abstract
- Lead-free (0.70-x)BiFeO3-0.30BaTiO3-xAgNbO3+5‰mol CuO (abbreviated as BF-BT-xAN) ceramics were fabricated using a modified thermal quenching technique. BF-BT-xAN ceramics are of a perovskite structure with morphotropic phase boundary (MPB) and show strong relaxor properties. Remarkably, the high recoverable energy storage density of 2.11 J/cm3 is obtained for BF-BT-xAN with x = 0.14. For the x = 0.14 ceramics, its energy storage efficiency is as high as 84 % at relative low field of 195 kV/cm, together with an outstanding thermal stability in a broad temperature range from 25 °C to 150 °C. In addition, this ceramic maintains superior energy storage performance even after 8 × 104 electrical cycles due to its high densification after doping Ag2O and Nb2O5. The result suggests that lead-free BF-BT-xAN ceramics may be promising candidate for dielectric energy storage application.
|
|
| 19. |
- Verenzuela, Daniel, 1988-, et al.
(författare)
-
Massive-MIMO Iterative Channel Estimation and Decoding (MICED) in the Uplink
- 2020
-
Ingår i: IEEE Transactions on Communications. - Piscataway, New Jersey, US : Institute of Electrical and Electronics Engineers (IEEE). - 0090-6778 .- 1558-0857. ; 68:2, s. 854-870
-
Tidskriftsartikel (refereegranskat)abstract
- Massive MIMO uses a large number of antennas to increase the spectral efficiency (SE) through spatial multiplexing of users, which requires accurate channel state information. It is often assumed that regular pilots (RP), where a fraction of the time-frequency resources is reserved for pilots, suffices to provide high SE. However, the SE is limited by the pilot overhead and pilot contamination. An alternative is superimposed pilots (SP) where all resources are used for pilots and data. This removes the pilot overhead and reduces pilot contamination by using longer pilots. However, SP suffers from data interference that reduces the SE gains. This paper proposes the Massive-MIMO Iterative Channel Estimation and Decoding (MICED) algorithm where partially decoded data is used as side-information to improve the channel estimation and increase SE. We show that users with precise data estimates can help users with poor data estimates to decode. Numerical results with QPSK modulation and LDPC codes show that the MICED algorithm increases the SE and reduces the block-error-rate with RP and SP compared to conventional methods. The MICED algorithm with SP delivers the highest SE and it is especially effective in scenarios with short coherence blocks like high mobility or high frequencies.
|
|
| 20. |
- Wang, Xiangjian, et al.
(författare)
-
Enhanced piezoelectric, electrocaloric and energy storage properties at high temperature in lead-free Bi0.5(Na1-xKx)0.5TiO3ceramics
- 2019
-
Ingår i: Ceramics International. - : Elsevier. - 0272-8842 .- 1873-3956. ; 45:4, s. 4274-4282
-
Tidskriftsartikel (refereegranskat)abstract
- The piezoelectric, electrocaloric and energy storage properties were systemically investigated in lead-free Bi0.5(Na1-xKx)0.5TiO3 ceramics from room temperature to high temperature region. These ceramics can be poled completely to obtain large piezoelectric coefficient (104–153 pC/N) at low electric field of ~30 kV/cm. The piezoelectric propertyshows good thermal stability due to high depolarization temperature (Td). For BNKT20, a large low electric field-induced strain of 0.36% is obtained at 120 °C under 50 kV/cm, the corresponding normalized strain coefficient is up to 720 pm/V, which is larger than other BNT-based ceramics at high temperature region. The electrocaloric properties of these ceramics are studied via indirect and direct methods. Large EC value (~1.08 K) in BNKT20ceramic is obtained at 50 kV/cm using indirect calculation. Above 100 °C, the dielectricenergy storage density and efficiency of BNKT20 is still up to ~0.85 J/cm3 and 0.75, respectively. The BNKTx ceramics may become promising candidates in the fields of actuators, electrocaloric cooling and energy storage at high temperature region.
|
|
| 21. |
- Wang, Xiangjian, et al.
(författare)
-
Ferroelectric and antiferroelectric distortions coupling of nitride perovskite LaWN3 under epitaxial strain using first-principles calculations
- 2022
-
Ingår i: Europhysics letters. - : Institute of Physics (IOP). - 0295-5075 .- 1286-4854. ; 140:5
-
Tidskriftsartikel (refereegranskat)abstract
- LaWN3, a novel nitride perovskite, have been synthesized and its piezoelectric properties have been investigated (TALLEY K. R. et at., Science, 374 (2021) 1488). However, the understanding of its ferroelectric properties under the external strain is still lacking. Here, the misfit-strain-dependent coupling between anti-ferrodistortions (AFD) and ferroelectric (FE) distortions has been studied by using a first-principle approach. It can be observed that AFD and FE distortions can work cooperatively with each other as the compressive strain increases, and the coupling energy between them is found to work in different ways under various strains. Our results show that the coupling tends to stabilize the ground structure when the compressive strain is smaller than -1.9%, it works oppositely when the compressive strain becomes larger than 1.9%. Our results can provide us with more hints about the influence of the epitaxial strains on the intrinsic coupling behavior in the perovskite ferroelectric compounds, which is very important for us to design and fabricate new kinds of functional materials.
|
|
| 22. |
- Wang, Xiangjian, et al.
(författare)
-
Multifunctionality in (K,Na)NbO3-based ceramic near polymorphic phase boundary
- 2021
-
Ingår i: Journal of Applied Physics. - : American Institute of Physics (AIP). - 0021-8979 .- 1089-7550. ; 130:6
-
Tidskriftsartikel (refereegranskat)abstract
- The 0.95K0.42Na0.58Nb0.96Sb0.04O3–0.02BaZrO3–0.03Bi0.5K0.5HfO3 ceramic was fabricated via a conventional solid-state reaction. This ceramic exhibits the diffuse polymorphic phase boundary (PPB) near room temperature. The dielectric, ferroelectric, electromechanical, electrocaloric, and dielectric energy storage properties were studied systemically. The normalized large signal d33* values are approximately 400–600 pm/V at measured temperatures and electric fields, which are larger than or comparable with the values reported in other lead-free compositions. The electrocaloric strength is enhanced at the broad region of PPB provided by the indirect and direct measurements. At low field of 30 kV/cm, the dielectric energy storage is ∼0.12–018 J/cm3 at relative broad temperature range due to the diffuse nature of polymorphic phase boundary. Theoretical simulations reveal that multi-element dopants, such as Sb5+, Hf4+, Zr4+, and Bi3+ ions, could induce the breaking of local structure symmetry in the orthorhombic phase to form the PPB. In addition, the charge distribution may also break the long-range ferroelectric order through the analysis of Bader charge. Our study suggests that the K0.5Na0.5NbO3-based ceramic exhibits improved performance and good thermal stability in piezoelectric, electrocaloric, and dielectric energy storage characteristics in terms of the design of multi-element dopants to form the PPB and it will benefit the promising applications in electronic devices.
|
|
| 23. |
- Zhang, Juqing, et al.
(författare)
-
Super-enhancers conserved within placental mammals maintain stem cell pluripotency
- 2022
-
Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences (PNAS). - 0027-8424 .- 1091-6490. ; 119:40
-
Tidskriftsartikel (refereegranskat)abstract
- Despite pluripotent stem cells sharing key transcription factors, their maintenance involves distinct genetic inputs. Emerging evidence suggests that super-enhancers (SEs) can function as master regulatory hubs to control cell identity and pluripotency in humans and mice. However, whether pluripotency-associated SEs share an evolutionary origin in mammals remains elusive. Here, we performed comprehensive comparative epigenomic and transcription factor binding analyses among pigs, humans, and mice to identify pluripotency-associated SEs. Like typical enhancers, SEs displayed rapid evolu-tion in mammals. We showed that BRD4 is an essential and conserved activator for mammalian pluripotency-associated SEs. Comparative motif enrichment analysis revealed 30 shared transcription factor binding motifs among the three species. The majority of transcriptional factors that bind to identified motifs are known regulators associated with pluripotency. Further, we discovered three pluripotency-associated SEs (SE-SOX2, SE-PIM1, and SE-FGFR1) that displayed remarkable conservation in pla-cental mammals and were sufficient to drive reporter gene expression in a pluripotency-dependent manner. Disruption of these conserved SEs through the CRISPR-Cas9 approach severely impaired stem cell pluripotency. Our study provides insights into the understanding of conserved regulatory mechanisms underlying the maintenance of plu-ripotency as well as species-specific modulation of the pluripotency-associated regula-tory networks in mammals.
|
|
