| 1. |
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- 2019
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Tidskriftsartikel (refereegranskat)
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| 2. |
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| 3. |
- Yu, Changxun, et al.
(författare)
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Effect of weathering on abundance and release of potentially toxic elements in soils developed on Lower Cambrian black shales, P. R. China
- 2012
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Ingår i: Environmental Geochemistry and Health. - : Springer. - 0269-4042 .- 1573-2983. ; 34:3, s. 375-390
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Tidskriftsartikel (refereegranskat)abstract
- This paper examines the geochemical features of 8 soil profiles developed on metalliferous black shales distributed in the central parts of the South China black shale horizon. The concentrations of 21 trace elements and 8 major elements were determined using ICP-MS and XRF, respectively, and weathering intensity (W) was calculated according to a new technique recently proposed in the literature. The data showed that the black shale soils inherited a heterogeneous geochemical character from their parent materials. A partial least square regression model and EFbedrock (enrichment factor normalized to underlying bedrock) indicated that W was not a major control in the redistribution of trace metals. Barium, Sn, Cu, V, and U tended to be leached in the upper soil horizons and trapped by Al and Fe oxides, whereas Sb, Cd, and Mo with negative EF values across the whole profiles may have been leached out during the first stage of pedogenesis (mainly weathering of black shale). Compared with the Chinese average soils, the soils were strongly enriched in the potentially toxic metals Mo, Cd, Sb, Sn, U, V, Cu, and Ba, among which the 5 first listed were enriched to the highest degrees. Elevated concentrations of these toxic metals can have a long-term negative effect on human health, in particular, the soils in mining areas dominated by strongly acidic conditions. As a whole, the black shale soils have much in common with acid sulfate soils. Therefore, black shale soils together with acid sulfate soils deserve more attention in the context of metal exposure and human health.
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| 4. |
- Ali, Asad, et al.
(författare)
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Gram-scale production of in-situ generated iron carbide nanoparticles encapsulated via nitrogen and phosphorous co-doped bamboo-like carbon nanotubes for oxygen evolution reaction
- 2023
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Ingår i: Materials Science for Energy Technologies. - : Elsevier. - 2589-2991. ; 6, s. 301-309
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Tidskriftsartikel (refereegranskat)abstract
- Optimizing electrocatalytic activity and recognizing the most reactive sites for oxygen evolution reaction (OER) electrocatalysts are valuable to the order of renewable power. In this research article, we explored an innovative in-situ annealing technique for constructing iron carbide nanoparticles (Fe3C NPs) encapsulated via nitrogen and phosphorous doped bamboo-shape carbon nanotubes (NP-CNTs) for OER. Interestingly, the constructed Fe3C NPs@NP-CNT-800 composite exhibited remarkable electrochemical operation and offered a stable current density of 10 mA/cm2 at a lower overpotential (280 mV) in an alkaline solution. Furthermore, an innovative Fe3C NPs@N,P-CNT-800 hybrid surpassed the standard RuO2 electrocatalyst in terms of OER performance and showed negligible degradation in chronoamperometric (21 h) and chronopotentiometry (3000 cycles) analyses. The remarkable performance and stability are ascribed to the Fe3C NPs, novel tubular bamboo-like morphology of its carbon materials, and heteroatom doping, which contribute to the electrochemical interfaces, large surface area, active catalytic sites, and rapid charge transfer kinetics.
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| 5. |
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| 6. |
- Andrady, Anthony, et al.
(författare)
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Environmental effects of ozone depletion and its interaction with climate change: Progress report 2007
- 2008
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Ingår i: Photochemical and Photobiological Sciences. - : Springer Science and Business Media LLC. - 1474-9092 .- 1474-905X. ; 7:1, s. 15-27
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Forskningsöversikt (refereegranskat)abstract
- This year theMontreal Protocol celebrates its 20th Anniversary. In September 1987, 24 countries signed the ‘Montreal Protocol on Substances that Deplete the Ozone Layer’. Today 191 countries have signed and have met strict commitments on phasing out of ozone depleting substances with the result that a 95% reduction of these substances has been achieved. The Montreal Protocol has also contributed to slowing the rate of global climate change, since most of the ozone depleting substances are also effective greenhouse gases. Even though much has been achieved, the future of the stratospheric ozone layer relies on full compliance of the Montreal Protocol by all countries for the remaining substances, including methyl bromide, as well as strict monitoring of potential risks from the production of substitute chemicals. Also the ozone depleting substances existing in banks and equipment need special attention to prevent their release to the stratosphere. Since many of the ozone depleting substances already in the atmosphere are long-lived, recovery cannot be immediate and present projections estimate a return to pre-1980 levels by 2050 to 2075. It has also been predicted that the interactions of the effects of the ozone layer and that of other climate change factors will become increasingly important.
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| 7. |
- Andrady, Anthony, et al.
(författare)
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Environmental effects of ozone depletion and its interactions with climate
- 2009
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Ingår i: Photochemical and Photobiological Sciences. - 1474-9092. ; 8:1, s. 13-22
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Forskningsöversikt (refereegranskat)abstract
- After the enthusiastic celebration of the 20th Anniversary of the Montreal Protocol on Substances that Deplete the Ozone Layer in 2007, the work for the protection of the ozone layer continues. The Environmental Effects Assessment Panel is one of the three expert panels within theMontreal Protocol. This “EEAP” deals with the increase of the UV irradiance on the Earth’s surface and its effects on human health, animals, plants, biogeochemistry, air quality and materials. For the past few years, interactions of ozone depletion with climate change have also been considered. It has become clear that the environmental problems will be long-lasting. In spite of the fact that the worldwide production of ozone depleting chemicals has already been reduced by 95%, the environmental disturbances are expected to persist for about the next half a century, even if the protective work is actively continued, and completed. The latest full report was published in Photochem. Photobiol. Sci., 2007, 6, 201–332, and the last progress report in Photochem. Photobiol. Sci., 2008, 7, 15–27. The next full report on environmental effects is scheduled for the year 2010. The present progress report 2008 is one of the short interim reports, appearing annually.
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| 8. |
- Chen, Shouzhi, et al.
(författare)
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Informing the SWAT model with remote sensing detected vegetation phenology for improved modeling of ecohydrological processes
- 2023
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Ingår i: Journal of Hydrology. - : Elsevier BV. - 0022-1694. ; 616
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Tidskriftsartikel (refereegranskat)abstract
- The Soil and Water Assessment Tool (SWAT) model has been widely applied for simulating the water cycle and quantifying the influence of climate change and anthropogenic activities on hydrological processes. A major uncertainty of SWAT stems from the poor representation of vegetation dynamics due to the use of a simplistic vegetation growth and development module. Using long-term remote sensing-based phenological data, the SWAT model's vegetation module was improved by adding a dynamic growth start date and the dynamic heat requirement for vegetation growth rather than using constant values. The new SWAT model was verified in the Han River basin, China, and found its performance was much improved in comparison with that of the original SWAT model. Specifically, the accuracy of the leaf area index (LAI) simulation improved notably (coefficient of determination (R2) increased by 0.193, Nash–Sutcliffe Efficiency (NSE) increased by 0.846, and percent bias decreased by 42.18 %), and that of runoff simulation improved modestly (R2 increased by 0.05 and NSE was similar). Additionally, it is found that the original SWAT model substantially underestimated evapotranspiration (Penman-Monteith method) in comparison with the new SWAT model (65.09 mm (or 22.17 %) for forests, 92.27 mm (or 32 %) for orchards, and 96.16 mm (or 36.4 %) for farmland), primarily due to the inaccurate representation of LAI dynamics. Our results suggest that an accurate representation of phenological dates in the vegetation growth module is important for improving the SWAT model performance in terms of estimating terrestrial water and energy balance.
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| 9. |
- Chen, Shouzhi, et al.
(författare)
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Vegetation phenology and its ecohydrological implications from individual to global scales
- 2022
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Ingår i: Geography and Sustainability. - : Elsevier BV. - 2096-7438 .- 2666-6839. ; 3:4, s. 334-338
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Tidskriftsartikel (refereegranskat)abstract
- The Earth is experiencing unprecedented climate change. Vegetation phenology has already showed strong response to the global warming, which alters mass and energy fluxes on terrestrial ecosystems. With technology and method developments in remote sensing, computer science and citizen science, many recent phenology-related studies have been focused on macrophenology. In this perspective, we 1) reviewed the responses of vegetation phenology to climate change and its impacts on carbon cycling, and reported that the effect of shifted phenology on the terrestrial carbon fluxes is substantially different between spring and autumn; 2) elaborated how vegetation phenology affects ecohydrological processes at different scales, and further listed the key issues for each scale, i.e., focusing on seasonal effect, local feedbacks and regional vapor transport for individual, watershed and global respectively); 3) envisioned the potentials to improve current hydrological models by coupling vegetation phenology-related processes, in combining with machine learning, deep learning and scale transformation methods. We propose that comprehensive understanding of climate-macrophenology-hydrology interactions are essential and urgently needed for enhancing our understanding of the ecosystem response and its role in hydrological cycle under future climate change.
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| 10. |
- Fa, Wenxin, et al.
(författare)
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Associations of Blood Absolute Neutrophil Count and Cytokines With Cognitive Function in Dementia-Free Participants : A Population-Based Cohort Study
- 2023
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Ingår i: The journals of gerontology. Series A, Biological sciences and medical sciences. - 1079-5006 .- 1758-535X.
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Tidskriftsartikel (refereegranskat)abstract
- Background: The relationships of neutrophils and cytokines with cognitive dysfunction are poorly defined. We aimed to investigate the association of peripheral blood absolute neutrophil count (ANC) with cognitive function in older adults and to further explore the mediating role of serum cytokines in this association.Methods: This population-based cohort study included 1 666 dementia-free participants (age ≥60 years) derived from baseline examinations (March–September 2018) of the Multimodal Intervention to Delay Dementia and Disability in Rural China (MIND-China); of these, 1 087 participants completed follow-up examinations in October–December 2019. We used a neuropsychological test battery to assess episodic memory, verbal fluency, attention, and executive function at the baseline and follow-up examinations. We used Mindray BC-6800 automated hematology analyzer to measure ANC and Meso Scale Discovery to measure serum interleukin-6 (IL-6) and eotaxin-3.Results: The linear regression analysis of cross-sectional data at baseline (n = 1 666) suggested that increased ANC was significantly associated with a lower episodic memory z score (β coefficient: −0.149, 95% CI: −0.274 to −0.023) and lower long-delayed free recall z score (−0.216, −0.361 to −0.070). Serum IL-6 and eotaxin-3 could mediate 16.16% to 20.21% and 7.55% to 9.35%, respectively, of these associations. The analysis of longitudinal data (n = 1 087) showed a J-shaped relationship of ANC with decline in episodic memory z score (p for nonlinear = .049), and a U-shaped relationship between ANC and decline in long-delayed free recall z score (p for nonlinear = .043).Conclusions: Increased neutrophils are associated with poor cognitive performance and accelerated decline in episodic memory, and the cross-sectional association is partly mediated by serum cytokines.
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| 11. |
- Fei, Keke, et al.
(författare)
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LcrQ coordinates with the YopD-LcrH complex to repress lcrF expression and control type III secretion by Yersinia pseudotuberculosis
- 2021
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Ingår i: mBio. - : American Society for Microbiology (ASM). - 2161-2129 .- 2150-7511. ; 12:3
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Tidskriftsartikel (refereegranskat)abstract
- Human-pathogenic Yersinia species employ a plasmid-encoded type III secretion system (T3SS) to negate immune cell function during infection. A critical element in this process is the coordinated regulation of T3SS gene expression, which involves both transcriptional and posttranscriptional mechanisms. LcrQ is one of the earliest identified negative regulators of Yersinia T3SS, but its regulatory mechanism is still unclear. In a previous study, we showed that LcrQ antagonizes the activation role played by the master transcriptional regulator LcrF. In this study, we confirm that LcrQ directly interacts with LcrH, the chaperone of YopD, to facilitate the negative regulatory role of the YopD-LcrH complex in repressing lcrF expression at the posttranscriptional level. Negative regulation is strictly dependent on the YopD-LcrH complex, more so than on LcrQ. The YopD-LcrH complex helps to retain cytoplasmic levels of LcrQ to facilitate the negative regulatory effect. Interestingly, RNase E and its associated protein RhlB participate in this negative regulatory loop through a direct interaction with LcrH and LcrQ. Hence, we present a negative regulatory loop that physically connects LcrQ to the posttranscriptional regulation of LcrF, and this mechanism incorporates RNase E involved in mRNA decay.
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| 12. |
- Han, Xiaolei, et al.
(författare)
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KIBRA regulates amyloid β metabolism by controlling extracellular vesicles secretion
- 2022
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Ingår i: EBioMedicine. - : Elsevier BV. - 2352-3964. ; 78
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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.
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| 13. |
- Jansson, Helen, 1964, et al.
(författare)
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Carbon enhanced cementitious coatings: Alternative anode materials for impressed current cathodic protection systems intended for reinforced concrete
- 2024
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Ingår i: Materials and Corrosion - Werkstoffe und Korrosion. - 1521-4176 .- 0947-5117. ; 75:6, s. 705-718
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Tidskriftsartikel (refereegranskat)abstract
- In this study, the functionality of self-formulated carbon-based conductive coatings (CBCCs) with incorporation of graphite as the anode in an impressed current cathodic protection system is studied. The anode materials are tested and evaluated for long-term durability and performance by an accelerated durability test method. The results show that the functional time is highly dependent on the acceleration factor, and thus the charge passed through the material during testing, as well as the material composition. From the results, there are also indications that the addition of graphene into the CBCC matrix has a positive effect on the homogeneity of the material, but without any major influence on the conductivity and performance.
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| 14. |
- Liu, Rui, et al.
(författare)
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Associations of sleep timing and time in bed with dementia and cognitive decline among Chinese older adults : A cohort study
- 2022
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Ingår i: Journal of The American Geriatrics Society. - : Wiley. - 0002-8614 .- 1532-5415. ; 70:11, s. 3138-3151
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Tidskriftsartikel (refereegranskat)abstract
- Background: The longitudinal associations of sleep timing and time in bed (TIB) with dementia and cognitive decline in older adults are unclear.Methods: This population-based cohort study used data from 1982 participants who were aged >= 60 years, free of dementia, and living in rural communities in western Shandong, China. At the baseline (2014) and follow-up (2018) examinations, sleep parameters were assessed using standard questionnaires. Cognitive function was measured using the Mini-Mental State Examination (MMSE). Dementia was diagnosed following the DSM-IV criteria, and the NIA-AA criteria for Alzheimer disease (AD). Data were analyzed using restricted cubic splines, Cox proportional-hazards models, and general linear models.Results: During the mean follow-up of 3.7 years, dementia was diagnosed in 97 participants (68 with AD). Restricted cubic spline curves showed J-shaped associations of sleep duration, TIB, and rise time with dementia risk, and a reverse J-shaped association with mid-sleep time. When sleep parameters were categorized into tertiles, the multivariable-adjusted hazard ratio (HR) of incident dementia was 1.69 (95%CI 1.01-2.83) for baseline sleep duration >8 hours (vs. 7-8 h), 2.17 (1.22-3.87) for bedtime before 9 p.m. (vs. 10 p.m. or later), and 2.00 (1.23-3.24) for mid-sleep time before 1 a.m. (vs. 1-1.5 a.m.). Early bedtime and mid-sleep time were significantly associated with incident AD (HR range: 2.25-2.51; p < 0.05). Among individuals who were free of dementia at follow-up, baseline long TIB, early bedtime and mid-sleep time, early and late rise time, and prolonged TIB and advanced bedtime and mid-sleep time from baseline to follow-up were associated with a greater decline in MMSE score (p < 0.05). These associations with cognitive decline were statistically evident mainly among men or participants who were aged 60-74 years.Conclusions: Long TIB and early sleep timing are associated with an increased risk of dementia, and the associations with greater cognitive decline are evident only among older people aged 60-74 years and men.
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| 15. |
- Liu, Shungang, et al.
(författare)
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The role of connectivity in significant bandgap narrowing for fused-pyrene based non-fullerene acceptors toward high-efficiency organic solar cells
- 2020
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Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry (RSC). - 2050-7488 .- 2050-7496. ; 8:12, s. 5995-6003
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Tidskriftsartikel (refereegranskat)abstract
- Great attention has been paid to developing low bandgap non-fullerene acceptors (NFAs) for matching wide bandgap donor polymers to increase the photocurrent and therefore the power conversion efficiencies (PCEs) of NFA organic solar cells, while pyrene-core based acceptor-donor-acceptor (A-D-A) NFAs have been mainly reported via the 2,9-position connection due to their bisthieno[3′,2′-b']thienyl[a,h]pyrene fused via a five-membered ring bridge at the ortho-position of pyrene as the representative one named FPIC5, which has prohibited further narrowing their energy gap. Herein, an acceptor FPIC6 was exploited by creating the 1,8-position connection through fusing as bisthieno[3′,2′-b′]thienyl[f-g,m-n]pyrene linked at the bay-position via a six-membered bridge, with enhanced push-pull characteristics within such A-D-A structure. As a structural isomer of FPIC5, FPIC6 exhibited a much lower bandgap of 1.42 eV (1.63 eV for FPIC5). Therefore, the photocurrent and PCE of PTB7-Th:FPIC6 cells were improved to 21.50 mA cm-2 and 11.55%, respectively, due to the balanced mobilities, better photoluminescence quenching efficiency and optimized morphology, which are both ∼40% better than those of PTB7-Th:FPIC5 cells. Our results clearly proved that a pyrene fused core with 1,8-position connection with electron-withdrawing end groups instead of 2,9-position connection is an efficient molecular design strategy to narrow the optical bandgap and improve the photovoltaic performance of NFA based OSCs.
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| 16. |
- Liu, Weihua, et al.
(författare)
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An empirical examination of the contents and evolution of the composing factors of logistics enterprise competitiveness: a perspective from China
- 2014
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Ingår i: International Journal of Logistics. - : Taylor & Francis Group. - 1367-5567 .- 1469-848X. ; 17:6, s. 459-484
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Tidskriftsartikel (refereegranskat)abstract
- Managers and researchers are increasingly interested in the factor that logistics enterprise competitiveness(LEC) has significant effects on the development of Chinese logistics enterprises, especially in view of theenterprise life cycle. This paper investigates the contents and evolution of the composing factors of LEC inChina by a survey.With Statistical Product and Service Solutions (SPSS 15.0) software, the factor analysismethod is used to determine the effects of each factor on LEC. Furthermore, the comparative analysismethod is applied to compare the composing factors of LEC in different types of logistics enterprises andat different enterprise life cycle stages. The results show that factors of LEC according to their descendingimportance level are corporate capabilities, corporate resources, and dynamic mechanism. Three kindsof corporate capabilities (financial management capability, logistics risk control capability, and humanresource management capability) and two kinds of corporate resources (corporate human resources andcorporate culture) have the greatest influence on the development of LEC, but in reality have poor practicalperformance, and hence deserve more consideration from the enterprises.
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| 17. |
- Peng, Bo, et al.
(författare)
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Geochemistry of major and trace elements and Pb-Sr isotopes of a weathering profile developed on the Lower Cambrian black shales in central Hunan, China
- 2014
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Ingår i: Applied Geochemistry. - : Elsevier BV. - 0883-2927 .- 1872-9134. ; 51, s. 191-203
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Tidskriftsartikel (refereegranskat)abstract
- This paper reports a geochemical study on the major and trace elements and Pb-Sr isotopes of a weathering profile developed in the Lower Cambrian black shales in central Hunan (China). Six weathering horizons were identified and sampled vertically throughout the profile. The chemical composition of the profile consists of variable concentrations of the major elements Fe2O3, FeO, MnO, MgO, CaO, Na2O, and P2O5 and of less variable concentrations of SiO2, TiO2, Al2O3, and K2O. The chemical change caused by weathering is estimated by mass-balance calculations, and the results show that the element mobility is characterised by substantial loss of SiO2, FeO, CaO, K2O, Na2O, LOI, Cr, V, Ba, Cs, Rb, Sr, U, and Th, and moderate loss of Al2O3, MgO, Fe2O3, Ni, Cu, Pb, Tl, Sn, Sc, Ge and REE (Y). The high field strength elements TiO2, Sn, Sc, U, Ga, Ge, Zr, Hf, Nb, and Ta were immobile during weathering. The chemical changes and the Pb-Sr isotopic data suggest that four types of chemical reactions occurred: the oxidation of sulphide minerals (e.g., pyrite) and organic carbon (OS), the dissolution of less resistant clinochlore-Ia, calcite, and P-bearing minerals (DL), the dissolution of detrital albite and microcline (DA), and the transformation of clay (TC) minerals (e.g., muscovite and illite-smectite). These chemical reactions then led to two stages of geochemical processes, an early stage of chemical differentiation and a later stage of chemical homogenisation. The chemical differentiation dominated by the OS, DL, and DA reactions, led to the leaching of mobile elements (e.g., MgO, Na2O, K2O, P2O5, Sr, and REE) and the redistribution of some less mobile elements (e.g., SiO2 and Al2O3). In contrast, the chemical homogenisation, which was caused by TC reactions, led to the leaching of both mobile and less mobile elements from the system and ultimately transformed the weathered black shales into soil. Soils derived from black shales in South China might result from the above two geochemical processes. (C) 2014 Elsevier Ltd. All rights reserved.
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| 18. |
- Song, Lin, et al.
(författare)
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KIBRA controls exosome secretion via inhibiting the proteasomal degradation of Rab27a
- 2019
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Exosomes are nanosized membrane vesicles released from cells after fusion of multivesicular bodies (MVBs) with the plasma membrane (PM) and play important roles in intercellular communication and numerous biological processes. However, the molecular mechanisms regulating exosome secretion remain poorly understood. Here we identify KIBRA as an adaptor-like protein that stabilizes Rab27a, which in turn controls exosome secretion both in vitro and in vivo. Knockdown or overexpression of KIBRA in neuronal and podocyte cell lines leads to a decrease or increase of exosome secretion, respectively, and KIBRA depletion increases MVB size and number. Comparing protein profiles between KIBRA knockout and wild-type mouse brain showed significantly decreased Rab27a, a small GTPase that regulates MVB-PM docking. Rab27a is stabilized by interacting with KIBRA, which prevents ubiquitination and degradation via the ubiquitin-proteasome pathway. In conclusion, we show that KIBRA controls exosome secretion via inhibiting the proteasomal degradation of Rab27a.
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| 19. |
- Sun, Yunhao, et al.
(författare)
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Analysis of Vapor-Liquid Interfacial Transport Resistivities with DGT-PC-SAFT Based on the General Approach
- 2022
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Ingår i: Industrial & Engineering Chemistry Research. - : American Chemical Society. - 0888-5885 .- 1520-5045. ; 61:43, s. 16352-16367
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Tidskriftsartikel (refereegranskat)abstract
- In this work, the DGT-PC-SAFT model was applied to calculate the interfacial transport resistivities between the vapor-liquid interface. In order to calculate the interfacial transport resistivities with DGT-PC-SAFT stably and efficiently, the general approach was combined with the Chebyshev spectral collocation method to solve the density profile using density gradient theory (DGT). Investigations have shown that using a suitable conformal map in the Chebyshev spectral collocation method can significantly reduce the collocation points required for the calculation of interfacial transport resistivities. Based on the developed algorithm, interfacial transport resistivities of n-alkane/nitrogen mixtures were predicted. However, the results revealed a certain deviation compared with those calculated with DFT-PC-SAFT, and the reason for this is discussed in this paper.
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| 20. |
- Tang, Liqiu, et al.
(författare)
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A Stacking Faults-Containing Silicogermanate with 24-Ring Channels and Unbranched Zweier Silica Double Chains
- 2012
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Ingår i: Crystal Growth & Design. - : American Chemical Society (ACS). - 1528-7483 .- 1528-7505. ; 12:7, s. 3714-3719
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Tidskriftsartikel (refereegranskat)abstract
- A novel open-framework silicogermanate SU-JU-14 (Stockholm University-Jilin University-Number 14), vertical bar NH3CH2CH2NH3 vertical bar(3)[Ge6.40Si0.60O15(OH)](2)[Ge0.73Si3.27O8], was synthesized by using ethylenediamine as the structure-directing agent under solvothermal conditions. Single-crystal structure analysis reveals that the crystal structure of SU-JU-14 consists of extended 24-ring channels built from [(Ge,Si)(7)O12O6/2(OH)](3-) [(Ge,Si)(7)] clusters and unbranched zweier silica double chains [Ge0.73Si3.27O4O8/2]. Charge neutrality is achieved by diprotonated ethylenediamine guest molecules. The structure consists of stacking faults of layered arrays in two different configurations along the a-axis. SU-JU-14 was characterized by X-ray diffraction, X-ray energy dispersive spectroscopy, scanning electron microscopy, nuclear magnetic resonance, inductively coupled plasma, and thermogravimetric analyses. Crystallographic data: monoclinic, space group C2/c, and unit cell parameters: a = 35.625 (7) angstrom, b = 28.580 (6) angstrom, c = 10.403 (2) angstrom, and beta = 98.30 (3)degrees.
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| 21. |
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| 22. |
- Tang, Tingfan, et al.
(författare)
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Sensitive and selective electrochemical determination of uric acid in urine based on ultrasmall iron oxide nanoparticles decorated urchin-like nitrogen-doped carbon
- 2022
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Ingår i: Colloids and Surfaces B. - : Elsevier. - 0927-7765 .- 1873-4367. ; 216
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Tidskriftsartikel (refereegranskat)abstract
- Hypercrosslinked pyrrole was synthesized via the Friedel–Crafts reaction and then carbonized to obtain urchin-like nitrogen-doped carbon (UNC). Ultrasmall iron oxide nanoparticles were then supported on UNC, and the composite was used to prepare an electrochemical sensor for detecting uric acid (UA) in human urine. FexOy/UNC was characterized and analyzed via scanning electron microscopy, transmission electron microscopy, energy dispersive spectrometry, X-ray diffraction, and X-ray photoelectron spectroscopy. A glassy carbon electrode (GCE) modified with FexOy/UNC was used as an electrochemical sensor to effectively identify UA. The electrochemical behavior of the FexOy/UNC-based UA sensor was studied using differential pulse stripping voltammetry, and the optimal conditions were determined by changing the amount of FexOy/UNC, pH of the buffer solution, deposition potential, and deposition time. Under optimal conditions, the FexOy/UNC-based electrochemical sensor detected UA in the range of 2–200 μM, where the limit of detection (LOD) for UA was 0.29 μM. Anti-interference experiments were performed, and the sensor was applied to the actual analysis of human urine samples. Urea, glucose, ascorbic acid, and many cations and anions present at 100-fold concentrations relative to UA did not strongly interfere with the response of the sensor to UA. The FexOy/UNC electrochemical sensor has high sensitivity and selectivity for uric acid in human urine samples and can be used for actual clinical testing of UA in urine.
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| 23. |
- Xu, Jingzhe, et al.
(författare)
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Geochemistry of soils derived from black shales in the Ganziping mine area, western Hunan, China
- 2013
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Ingår i: Environmental Earth Sciences. - : Springer Science and Business Media LLC. - 1866-6280 .- 1866-6299. ; 70:1, s. 175-190
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Tidskriftsartikel (refereegranskat)abstract
- The geochemistry of major and trace elements (including heavy metals and rare earth elements) of the fresh and weathered black shales, and the soils derived from black shales in the Ganziping mine area in western Hunan province (China) were studied using the following techniques: X-ray fluorescence (XRF), inductively coupled plasma mass spectrometer (ICP-MS) and X-ray diffraction (XRD). The results show that the black-shale soils are significantly enriched with Al2O3 and Fe2O3, and depleted of mobile elements CaO, Na2O and K2O. The soils are also highly enriched with heavy metals U, V, Ni, Ba, Cu, Zn and Pb, that may cause potential heavy-metal contamination of the soils. Composition of the soils is homogeneous compared to the weathered black shales, for which the concentrations of major elements except CaO and Na2O, and trace elements except heavy metals (U, V, Ni, Ba, Cu, Zn and Pb) as well as the mobile Sr, show lower variations than in the weathered black shales. Ratios of Zr/Hf, Ta/Nb, Y/Ho, Nd/Sm, and Ti/(Ti + Zr), of the soils are also less variable, with values constantly similar to that of the fresh and weathered black shales correspondingly. Thus, components of the soils are believed to be contributed from the parent black shales through weathering and pedogenesis. It is concluded that the soils were formed by at least two stages of geochemical processes: the early stage of chemical differentiation and the later stage of chemical homogenization. The chemical differentiation that was taken during black-shale weathering might have caused the depletion of CaO and Na2O, and the enrichment of Al2O3 and Fe2O3; while the chemical homogenization that was taken during pedogenesis led to the depletion of SiO2 and K2O, and to the further enrichment of Al2O3 and Fe2O3. The heavy-metal enrichment (contamination) of the soils was then genetically related to the enrichment of Al2O3 and Fe2O3 in the soils.
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| 24. |
- Zhang, Hongpeng, et al.
(författare)
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Influence of Metal Gate Electrodes on Electrical Properties of Atomic-Layer-Deposited Al-Rich HfAlO/Ga2O3 MOSCAPs
- 2020
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Ingår i: IEEE Transactions on Electron Devices. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 0018-9383 .- 1557-9646. ; 67:4, s. 1730-1736
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Tidskriftsartikel (refereegranskat)abstract
- As the p-type doping beta-Ga2O3 is absent up to now, metal gate (MG) stacks with high work functions are expected to benefit the fabrication of normally-OFF beta-Ga2O3 transistors. In this article, the electrical characteristics of beta-Ga2O3 metal-electrode-gated metal-oxidesemiconductor (MOS) deviceswith Al-rich HfAlO dielectrics and different MG stacks (Ni, Au, Pt, and Ti) are evaluated. The interface state density (Dit) of HfAlO/ beta-Ga2O3 interface is characterized based on the frequency-dependent capacitance-voltage (C-V) and photo-assisted deep ultraviolet (DUV) C-V measurements. An average Dit of 4.45 x 10(11) eV(-1)cm(-2) is extracted from the photo-assisted (deep UV) C-V measurement, while a large amount of border traps, negative fixed charges, and deep traps is also induced at the oxide layer and/or HfAlO/beta-Ga2O3 interface. Then, this article investigates the evaluations of Ti, Ni, Au, and Pt as candidate MGs for beta-Ga2O3 MOS using Al-rich HfAlO as gate dielectric. The obvious flat-band voltage (V-FB) shift and gate leakage variation are observed in beta-Ga2O3 capacitors with different MG solutions, indicating that HfAlO dielectric combined with Ni, Au, and Pt MGs is promising to facilitate some beneficial modifications of normally-OFF beta-Ga2O3 transistors, while Ti electrode ismore suitable for normally-ON beta-Ga2O3 transistors. This article provides an additional practical guideline for choosing the appropriate MG stacks and potential gate dielectric to the development of normally-OFF Ga2O3 transistors.
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| 25. |
- Zhang, Hongpeng, et al.
(författare)
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Progress of Ultra-Wide Bandgap Ga < sub > 2 O < sub > 3 Semiconductor Materials in Power MOSFETs
- 2020
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Ingår i: IEEE transactions on power electronics. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 0885-8993 .- 1941-0107. ; 35:5, s. 5157-5179
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Tidskriftsartikel (refereegranskat)abstract
- As a promising ultra-wide bandgap semiconductor, the <italic>& x03B2;</italic>-phase of Ga<sub>2</sub>O<sub>3</sub> has attracted more and more interest in the field of power electronics due to its ultra-wide bandgap (4.8 & x00A0;eV), high theoretical breakdown electric field (8 MV & x002F;cm), and large Baliga & x0027;s figure of merit, which is deemed as a potential candidate for next generation high-power electronics, including diodes, field effect transistors (FETs), etc. In this article, we introduce the basic material properties of Ga<sub>2</sub>O<sub>3</sub>, and review the recent progress and advances of <italic>& x03B2;</italic>-Ga<sub>2</sub>O<sub>3</sub> based metal & x2013;oxide & x2013;semiconductor field-effect transistors (<sc>mosfet</sc>s). Due to the problematic p-type doping technology up to now, the enhancement-mode (E-mode) <italic>& x03B2;</italic>-Ga<sub>2</sub>O<sub>3</sub> FETs face more difficulties, compared with depletion mode (D-mode). This article focuses on reviewing the recent progress of E-mode Ga<sub>2</sub>O<sub>3</sub> <sc>mosfet</sc>s, summarizing and comparing various feasible solutions when p-type doping is absent. Furthermore, the device fabrication and performances of state-of-art <italic>& x03B2;</italic>-Ga<sub>2</sub>O<sub>3</sub> <sc>mosfet</sc>s, including D-mode, E-mode, and planar & x002F;vertical structure are fully discussed and compared, as well as potential solutions to the challenges of Ga<sub>2</sub>O<sub>3</sub> FETs.
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| 26. |
- Zhang, Hongpeng, et al.
(författare)
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Stress-induced charge trapping and electrical properties of atomic-layer-deposited HfAlO/Ga2O3 metal-oxide-semiconductor capacitors
- 2019
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Ingår i: Journal of Physics D. - : IOP PUBLISHING LTD. - 0022-3727 .- 1361-6463. ; 52:21
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Tidskriftsartikel (refereegranskat)abstract
- Electrical properties and trapping characteristics of an atomic layer deposited Al-rich HfAlO/beta-Ga2O3 capacitor were evaluated via constant-voltage stress (CVS), capacitance-voltage (C-V), and current-voltage (I-V) measurements. The magnitude of the stress-induced charge trapping increases with increasing voltage and time. The effective charges (N-eff) including the border traps located in near-interface oxide, interface traps (D-it) of HfAlO/beta-Ga2O3 interface, and fixed charges contribute significantly to the observed charge trapping, and it is found that interface traps contribute more under a large stress bias, compared with border traps. In addition, the effective charge density is increased with stress time, implying that the contribution of negative sheet charges during the CVS process might not be negligible. Measurements of oxide permittivity (10.74), interface state density (D-it similar to 1 x 10(12) eV(-1) cm(-2)), and gate leakage current (1.18 x 10( -5) A cm(-2) at +10 V) have been extracted, suggesting the great electrical properties of Al-rich HfAlO/beta-Ga203 MOSCAP. According to the above analysis, Al-rich HfAlO is an attractive candidate for normally off Ga2O3 transistors.
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