| 1. |
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| 2. |
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| 3. |
- Klionsky, Daniel J., et al.
(författare)
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Guidelines for the use and interpretation of assays for monitoring autophagy
- 2012
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Ingår i: Autophagy. - : Informa UK Limited. - 1554-8635 .- 1554-8627. ; 8:4, s. 445-544
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Forskningsöversikt (refereegranskat)abstract
- In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
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| 4. |
- Beal, Jacob, et al.
(författare)
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Robust estimation of bacterial cell count from optical density
- 2020
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Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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| 5. |
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- 2019
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Tidskriftsartikel (refereegranskat)
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| 6. |
- Ai, Chao, et al.
(författare)
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Current Development on Origami/Kirigami‐Inspired Structure of Creased Patterns toward Robotics
- 2021
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Ingår i: Advanced Engineering Materials. - : Wiley. - 1438-1656 .- 1527-2648. ; 23:10, s. 2100473-2100473
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Tidskriftsartikel (refereegranskat)abstract
- Origami/kirigami, the ancient art of paper folding and cutting techniques, has provided considerable inspiration for structural design routes in the engineering and medical fields over the last few decades. The practicability of the methods and concepts of origami/kirigami has been demonstrated in several emerging classes of technologies, e.g., stretchable electronics, deformable devices, self-assembly fabrication, etc. More and more related products are produced pursuing a folding form for better storage, deformation capacity, and multifunction realization. Herein, the innovative creased patterns of origami/kirigami designs are distinguished and discussed, and the four most widely used creased pattern types are introduced, which may potentially provide origami/kirigami related inspiration and additional solutions toward many research fields.
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| 7. |
- Chen, I-Hua, et al.
(författare)
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Psychometric properties of the Depression, Anxiety, and Stress Scale (DASS-21) among different Chinese populations : A cross-sectional and longitudinal analysis
- 2023
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Ingår i: Acta Psychologica. - : Elsevier. - 0001-6918 .- 1873-6297. ; 240
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Tidskriftsartikel (refereegranskat)abstract
- Given that there is limited evidence concerning the psychometric properties of DASS-21 when applied to primary school students, the present study undertook a comprehensive exploration of the psychometric evidence supporting the use of the DASS-21 within this demographic. The research comprised three studies. In Study 1, the basic psychometric properties of internal consistency and construct validity were examined. A total of 3138 primary school students from three provinces in mainland China participated. The internal reliability of the overall scale was 0.93, and for all the subscales, it was higher than 0.80. Construct validity was partially supported. Both exploratory and confirmatory factor analyses upheld the factorial validity of the original three-factor structure. While convergent validity was established, the results showed unsatisfactory discriminant validity. The bifactor model showed that DASS-21 raw scores predominantly indicated the general factor, evidenced by the high explained common variance and omega-hierarchical values. However, the contributions from the three specific factors were minimal, with their omega hierarchical values all below 0.15. In Study 2, a longitudinal design was adopted, tracking 1366 primary school students from Southwest China over a three-month interval. The results further confirmed that the DASS-21 exhibited scalar time-invariance. The latent mean analysis showed that there were no statistically significant differences in the latent means of depression, anxiety, and stress between Time 1 and Time 2. In Study 3, which included 364 college students and 483 enterprise workers, the results demonstrated that the DASS-21 had measurement invariance across different populations. The latent mean analysis further confirmed that, in terms of the latent mean of all three subscales, both college students and enterprise workers had significantly higher scores than primary school students. Overall, the findings indicated that the DASS-21 is a suitable tool for screening schoolchildren for general psychological distress, but it is not suitable for discerning distinct negative mood state disorders.
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| 8. |
- Cheng, Huailei, et al.
(författare)
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Truck platooning reshapes greenhouse gas emissions of the integrated vehicle-road infrastructure system
- 2023
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Ingår i: Nature Communications. - 2041-1723 .- 2041-1723. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- Reducing greenhouse gas emissions has turned into a pillar of climate change mitigation. Truck platooning is proposed as a strategy to lower emissions from vehicles on roads. However, the potential interactive impacts of this technology on road infrastructure emissions remain unclear. Here, we evaluate the decarbonization effects of truck platooning on the integrated vehicle-road system at a large-scale road network level, spanning 1457 road sections across North America. We show that truck platooning decreases emissions induced by truck operations, but it degrades faster the durability of road infrastructure and leads to a 27.9% rise in road emissions due to more frequent maintenance work. Overall, truck platooning results in a 5.1% emission reduction of the integrated vehicle-road system. In contrast to the benefits of emission reduction, truck platooning leads to additional financial burdens on car users and transportation agencies, calling for the consideration of tradeoffs between emissions and costs and between agencies and users. Our research provides insights into the potential applications of truck platooning to mitigate climate change.
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| 9. |
- Han, Shuangshuang, et al.
(författare)
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Application value of CyTOF 2 mass cytometer technology at single-cell level in human gastric cancer cells
- 2019
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Ingår i: Experimental Cell Research. - : Elsevier. - 0014-4827 .- 1090-2422. ; 384:1
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Tidskriftsartikel (refereegranskat)abstract
- Chemotherapy and radiotherapy are main adjuvant therapies for the treatment of gastric cancer, the treatment effects are individual difference, but the specific mechanism is unknown. CyTOF 2 mass cytometer (CyTOF) enables the detecting up to 135 parameters on single cell, the emergence of which is an opportunity for proteomics research. We first tried to apply CyTOF technique to gastric cancer cells. We verified applicability of CyTOF in gastric cancer cells, and analyzed the responses of seventeen proteins to chemoradiotherapy in human gastric cancer AGS cells. To analyze the high dimensional CyTOF data, we used two statistical and visualization tools including viSNE and Citrus. Two specific clusters were found which had differences in protein expression profiles. CyTOF technology is proved feasibility and value at single cell level of gastric cancer.
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| 10. |
- He, Yafang, et al.
(författare)
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Metabolomic Changes Upon Conjugated Linoleic Acid Supplementation and Predictions of Body Composition Responsiveness
- 2022
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Ingår i: Journal of Clinical Endocrinology and Metabolism. - : The Endocrine Society. - 1945-7197 .- 0021-972X. ; 107:9, s. 2606-2615
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Tidskriftsartikel (refereegranskat)abstract
- Context Conjugated linoleic acid (CLA) may optimize body composition, yet mechanisms underlining its benefits are not clear in humans. Objective We aimed to reveal the CLA-induced changes in the plasma metabolome associated with body composition improvement and the predictive performance of baseline metabolome on intervention responsiveness. Methods Plasma metabolome from overnight fasted samples at pre- and post-intervention of 65 participants in a 12-week randomized, placebo-controlled trial (3.2 g/day CLA vs 3.2 g/day sunflower oil) were analyzed using untargeted LC-MS metabolomics. Mixed linear model and machine learning were applied to assess differential metabolites between treatments, and to identify optimal panel (based on baseline conventional variables vs metabolites) predicting responders of CLA-derived body composition improvement (increased muscle variables or decreased adiposity variables) based on dual-energy x-ray absorptiometry. Results Compared with placebo, CLA altered 57 metabolites (P
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| 11. |
- Jiang, Xia, et al.
(författare)
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ITGB4 as a novel serum diagnosis biomarker and potential therapeutic target for colorectal cancer
- 2021
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Ingår i: Cancer Medicine. - : Wiley. - 2045-7634. ; 10:19, s. 6823-6834
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Tidskriftsartikel (refereegranskat)abstract
- Purpose To develop new and effective biomarkers for the diagnosis of colorectal cancer (CRC). Experimental design The serum expression of ITGB4 (49 CRC and 367 HC) was detected by enzyme-linked immunosorbent assay (ELISA), and its diagnostic value was analyzed using the receiver operating characteristic (ROC) curve. The sensitivity and specificity of ITGB4 in CRC diagnosis were calculated through statistical analysis. The optimal clinical cutoff value was calculated using the Youden index, and diagnostic efficacy was analyzed in a larger serum sample (98 CRC and 1631 non-CRC). The expression of ITGB4 was measured by CyTOF (cell experimental technology) at the single-cell level, and characteristics were analyzed using viSNE and SPADE TREE. Results Serum ITGB4 and CEA levels were significantly higher in CRC patients than in HC and non-CRC patients. The use of serum ITGB4 levels for the diagnosis of CRC has a high sensitivity (79%) but not high specificity when the clinical cutoff value was 0.70 ng/mL. However, the optimal cutoff value was 1.6 ng/mL with 86.2% specificity and 52.0% sensitivity, and the diagnostic efficacy was greatly improved with high specificity (82.0%) and sensitivity (71.4%) when combined with CEA. ITGB4 expression characteristics were measured and related to the expression of EpCAM, Ck8/18, and perforin at the single-cell level. Single-cell analysis showed that cell clusters with low expression of CK8/18 and ITGB4 were more sensitive to 5FU and radiotherapy (RT). Conclusions ITGB4 is an effective diagnostic serum biomarker and a potential therapeutic target for CRC.
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| 12. |
- Johansson, Leif I, et al.
(författare)
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Li induced effects in the core level and pi-band electronic structure of graphene grown on C-face SiC
- 2015
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Ingår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films. - : American Institute of Physics (AIP). - 0734-2101 .- 1520-8559. ; 33:6
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Tidskriftsartikel (refereegranskat)abstract
- Studies of the effects induced in the electronic structure after Li deposition, and subsequent heating, on graphene samples prepared on C-face SiC are reported. The as prepared graphene samples are essentially undoped, but after Li deposition, the Dirac point shifts down to 1.2 eV below the Fermi level due to electron doping. The shape of the C 1s level also indicates a doping concentration of around 10(14) cm(-2) after Li deposition, when compared with recent calculated results of core level spectra of graphene. The C 1s, Si 2p, and Li 1s core level results show little intercalation directly after deposition but that most of the Li has intercalated after heating at 280 degrees C. Heating at higher temperatures leads to desorption of Li from the sample, and at 1030 degrees C, Li can no longer be detected on the sample. The single pi-band observable from multilayer C-face graphene samples in conventional angle resolved photoelectron spectroscopy is reasonably sharp both on the initially prepared sample and after Li deposition. After heating at 280 degrees C, the p-band appears more diffuse and possibly split. The Dirac point becomes located at 0.4 eV below the Fermi level, which indicates occurrence of a significant reduction in the electron doping concentration. Constant energy photoelectron distribution patterns extracted from the as prepared graphene C-face sample and also after Li deposition and heating at 280 degrees C look very similar to earlier calculated distribution patterns for monolayer graphene. (C) 2015 Author(s).
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| 13. |
- Johansson, Leif I., et al.
(författare)
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Multiple π-bands and Bernal stacking of multilayer graphene on C-face SiC, revealed by nano-Angle Resolved Photoemission
- 2014
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Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 4:4157
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Tidskriftsartikel (refereegranskat)abstract
- Only a single linearly dispersing π-band cone, characteristic of monolayer graphene, has so far been observed in Angle Resolved Photoemission (ARPES) experiments on multilayer graphene grown on C-face SiC. A rotational disorder that effectively decouples adjacent layers has been suggested to explain this. However, the coexistence of μm-sized grains of single and multilayer graphene with different azimuthal orientations and no rotational disorder within the grains was recently revealed for C-face graphene, but conventional ARPES still resolved only a single π-band. Here we report detailed nano-ARPES band mappings of individual graphene grains that unambiguously show that multilayer C-face graphene exhibits multiple π-bands. The band dispersions obtained close to the K-point moreover clearly indicate, when compared to theoretical band dispersion calculated in the framework of the density functional method, Bernal (AB) stacking within the grains. Thus, contrary to earlier claims, our findings imply a similar interaction between graphene layers on C-face and Si-face SiC.
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| 14. |
- Johansson, Leif I, et al.
(författare)
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Na induced changes in the electronic band structure of graphene grown on C-face SiC
- 2013
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Ingår i: Graphene. - : Scientific Research Publishing. - 2169-3439 .- 2169-3471. ; 2:1, s. 1-7
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Tidskriftsartikel (refereegranskat)abstract
- Studies of the effects induced on the electron band structure after Na deposition, and subsequent heating, on a C-face 2 MLs graphene sample are reported. Na deposition shifts the Dirac point downwards from the Fermi level by about 0.5 eV due to electron doping. After heating at temperatures from around 120℃ to 300℃,thep-band appears considerably broadened. Collected Si 2p and Na 2p spectra then indicate Na intercalation in between the graphene layers and at the graphene SiC interface. The broadening is therefore interpreted to arise from the presence of two slightly shifted, but not clearly resolved,p-bands. Constant energy photoelectron distribution patterns, E(kx,ky);s, extracted from the clean 2MLs graphene C-face sample look very similar to earlier calculated distribution patterns for monolayer, but not Bernal stacked bilayer, graphene. After Na deposition the patterns extracted at energies below the Dirac point appear very similar so the doping had no pronounced effect on the shape or intensity distribution. At energies above the Dirac point the extracted angular distribution patterns show the flipped, “mirrored”, intensity distribution predicted for monolayer graphene at these energies. An additional weaker outer band is also discernable at energies above the Dirac point, which presumably is induced by the deposited Na.
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| 15. |
- Johansson, Leif, et al.
(författare)
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Is the Registry Between Adjacent Graphene Layers Grown on C-Face SiC Different Compared to That on Si-Face SiC
- 2013
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Ingår i: Crystals. - : MDPI AG. - 2073-4352. ; 3:1, s. 1-13
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Tidskriftsartikel (refereegranskat)abstract
- Graphene grown on C-face SiC substrates using two procedures, high and low growth temperature and different ambients, was investigated using Low Energy Electron Microscopy (LEEM), X-ray Photo Electron Electron Microscopy (XPEEM), selected area Low Energy Electron Diffraction (μ-LEED) and selected area Photo Electron Spectroscopy (μ-PES). Both types of samples showed formation of μm-sized grains of graphene. The sharp (1 × 1) μ-LEED pattern and six Dirac cones observed in constant energy photoelectron angular distribution patterns from a grain showed that adjacent layers are not rotated relative to each other, but that adjacent grains in general have different azimuthal orientations. Diffraction spots from the SiC substrate appeared in μ-LEED patterns collected at higher energies, showing that the rotation angle between graphene and SiC varied. C 1s spectra collected did not show any hint of a carbon interface layer. A hydrogen treatment applied was found to have a detrimental effect on the graphene quality for both types of samples, since the graphene domain/grain size was drastically reduced. From hydrogen treated samples, μ-LEED showed at first a clear (1 × 1) pattern, but within minutes, a pattern containing strong superstructure spots, indicating the presence of twisted graphene layers. The LEED electron beam was found to induce local desorption of hydrogen. Heating a hydrogenated C-face graphene sample did not restore the quality of the original as-grown sample.
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| 16. |
- Kanoni, Stavroula, et al.
(författare)
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Implicating genes, pleiotropy, and sexual dimorphism at blood lipid loci through multi-ancestry meta-analysis.
- 2022
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Ingår i: Genome biology. - : Springer Science and Business Media LLC. - 1474-760X .- 1465-6906 .- 1474-7596. ; 23:1
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Tidskriftsartikel (refereegranskat)abstract
- Genetic variants within nearly 1000 loci are known to contribute to modulation of blood lipid levels. However, the biological pathways underlying these associations are frequently unknown, limiting understanding of these findings and hindering downstream translational efforts such as drug target discovery.To expand our understanding of the underlying biological pathways and mechanisms controlling blood lipid levels, we leverage a large multi-ancestry meta-analysis (N=1,654,960) of blood lipids to prioritize putative causal genes for 2286 lipid associations using six gene prediction approaches. Using phenome-wide association (PheWAS) scans, we identify relationships of genetically predicted lipid levels to other diseases and conditions. We confirm known pleiotropic associations with cardiovascular phenotypes and determine novel associations, notably with cholelithiasis risk. We perform sex-stratified GWAS meta-analysis of lipid levels and show that 3-5% of autosomal lipid-associated loci demonstrate sex-biased effects. Finally, we report 21 novel lipid loci identified on the X chromosome. Many of the sex-biased autosomal and X chromosome lipid loci show pleiotropic associations with sex hormones, emphasizing the role of hormone regulation in lipid metabolism.Taken together, our findings provide insights into the biological mechanisms through which associated variants lead to altered lipid levels and potentially cardiovascular disease risk.
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| 17. |
- Knowles, Joshua W., et al.
(författare)
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Identification and validation of N-acetyltransferase 2 as an insulin sensitivity gene
- 2015
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Ingår i: Journal of Clinical Investigation. - 0021-9738 .- 1558-8238. ; 125:4, s. 1739-1751
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Tidskriftsartikel (refereegranskat)abstract
- Decreased insulin sensitivity, also referred to as insulin resistance (IR), is a fundamental abnormality in patients with type 2 diabetes and a risk factor for cardiovascular disease. While IR predisposition is heritable, the genetic basis remains largely unknown. The GENEticS of Insulin Sensitivity consortium conducted a genome-wide association study (GWAS) for direct measures of insulin sensitivity, such as euglycemic clamp or insulin suppression test, in 2,764 European individuals, with replication in an additional 2,860 individuals. The presence of a nonsynonymous variant of N-acetyltransferase 2 (NAT2) [rs1208 (803A>G, K268R)] was strongly associated with decreased insulin sensitivity that was independent of BMI. The rs1208 "A" allele was nominally associated with IR-related traits, including increased fasting glucose, hemoglobin A1C, total and LDL cholesterol, triglycerides, and coronary artery disease. NAT2 acetylates arylamine and hydrazine drugs and carcinogens, but predicted acetylator NAT2 phenotypes were not associated with insulin sensitivity. In a murine adipocyte cell line, silencing of NAT2 ortholog Nat1 decreased insulin-mediated glucose uptake, increased basal and isoproterenol-stimulated lipolysis, and decreased adipocyte differentiation, while Nat1 overexpression produced opposite effects. Nat1-deficient mice had elevations in fasting blood glucose, insulin, and triglycerides and decreased insulin sensitivity, as measured by glucose and insulin tolerance tests, with intermediate effects in Nat1 heterozygote mice. Our results support a role for NAT2 in insulin sensitivity.
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| 18. |
- Li, Weidong, et al.
(författare)
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Selective Disassembly Planning for Sustainable Management of Waste Electrical and Electronic Equipment
- 2013
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Ingår i: Re-engineering Manufacturing for Sustainability. - Singapore : Springer Singapore. ; , s. 341-346
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Konferensbidrag (refereegranskat)abstract
- Waste Electrical and Electronic Equipment (WEEE) are one of the most significant waste streams in modern societies. Full disassembly of WEEE is rarely an ideal solution due to high disassembly costs. Selective disassembly, which prioritizes operations for partial disassembly according to the legislative and economic considerations of specific stakeholders, is becoming an important yet still challenging research topic in recent years. In this paper, a Particle Swarm Optimization (PSO)-based selective disassembly planning method embedded with customizable decision-making models has been developed. The developed method is flexible to handle WEEE to meet the various requirements of stakeholders, and is capable to achieve optimized selective plans. Practical cases on Liquid Crystal Display (LCD) televisions have been used to verify and demonstrate the effectiveness of the research in application scenarios.
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| 19. |
- Li, Yafang, et al.
(författare)
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Lung cancer in ever- and never-smokers : findings from multi-population GWAS studies
- 2024
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Ingår i: Cancer Epidemiology, Biomarkers and Prevention. - : American Association For Cancer Research (AACR). - 1055-9965 .- 1538-7755. ; 33:3, s. 389-399
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Clinical, molecular, and genetic epidemiology studies displayed remarkable differences between ever- and never-smoking lung cancer.METHODS: We conducted a stratified multi-population (European, East Asian, and African descent) association study on 44,823 ever-smokers and 20,074 never-smokers to identify novel variants that were missed in the non-stratified analysis. Functional analysis including expression quantitative trait loci (eQTL) colocalization and DNA damage assays, and annotation studies were conducted to evaluate the functional roles of the variants. We further evaluated the impact of smoking quantity on lung cancer risk for the variants associated with ever-smoking lung cancer.RESULTS: Five novel independent loci, GABRA4, intergenic region 12q24.33, LRRC4C, LINC01088, and LCNL1 were identified with the association at two or three populations (P < 5 × 10-8). Further functional analysis provided multiple lines of evidence suggesting the variants affect lung cancer risk through excessive DNA damage (GABRA4) or cis-regulation of gene expression (LCNL1). The risk of variants from 12 independent regions, including the well-known CHRNA5, associated with ever-smoking lung cancer was evaluated for never-smokers, light-smokers (packyear ≤ 20), and moderate-to-heavy-smokers (packyear > 20). Different risk patterns were observed for the variants among the different groups by smoking behavior.CONCLUSIONS: We identified novel variants associated with lung cancer in only ever- or never-smoking groups that were missed by prior main-effect association studies. IMPACT: Our study highlights the genetic heterogeneity between ever- and never-smoking lung cancer and provides etiologic insights into the complicated genetic architecture of this deadly cancer.
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| 20. |
- Liu, Ya, 1991, et al.
(författare)
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Surface modification of graphene for use as a structural Fortifier in water-borne epoxy coatings
- 2019
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Ingår i: Coatings. - : MDPI AG. - 2079-6412. ; 9:11
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Tidskriftsartikel (refereegranskat)abstract
- Graphene, the typical two-dimensional sp2 hybridized carbon allotrope, is widely used as a filler for improving the mechanical performance of polymers. However, its superhydrophobic surface makes it a big challenge to obtain stable graphene dispersions, especially in water-borne systems. On the contrary, graphene oxide (GO) shows excellent dispersibility in water, but strong oxidants and acids destroy its structure and degrade its mechanical properties. This largely limits its application in water-borne coatings. In this work, graphene from mechanical exfoliation was surface modified by p-aminophenol derived diazonium salt to achieve a homogenous dispersion. Moreover, the hydroxyl groups in p-aminophenol are able to combine with epoxy resins during the curing process to improve mechanical performance of the final coatings. The result shows that functionalized graphene shows a lower coefficient of friction and better abrasion resistance compared to GO.
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| 21. |
- Long, Feiwu, et al.
(författare)
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The impact of immunoglobulin G N-glycosylation level on COVID-19 outcome: evidence from a Mendelian randomization study
- 2023
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Ingår i: Frontiers in Immunology. - : FRONTIERS MEDIA SA. - 1664-3224. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundThe coronavirus disease 2019 (COVID-19) pandemic has exerted a profound influence on humans. Increasing evidence shows that immune response is crucial in influencing the risk of infection and disease severity. Observational studies suggest an association between COVID-19 and immunoglobulin G (IgG) N-glycosylation traits, but the causal relevance of these traits in COVID-19 susceptibility and severity remains controversial.MethodsWe conducted a two-sample Mendelian randomization (MR) analysis to explore the causal association between 77 IgG N-glycosylation traits and COVID-19 susceptibility, hospitalization, and severity using summary-level data from genome-wide association studies (GWAS) and applying multiple methods including inverse-variance weighting (IVW), MR Egger, and weighted median. We also used Cochrans Q statistic and leave-one-out analysis to detect heterogeneity across each single nucleotide polymorphism (SNP). Additionally, we used the MR-Egger intercept test, MR-PRESSO global test, and PhenoScanner tool to detect and remove SNPs with horizontal pleiotropy and to ensure the reliability of our results.ResultsWe found significant causal associations between genetically predicted IgG N-glycosylation traits and COVID-19 susceptibility, hospitalization, and severity. Specifically, we observed reduced risk of COVID-19 with the genetically predicted increased IgG N-glycan trait IGP45 (OR = 0.95, 95% CI = 0.92-0.98; FDR = 0.019). IGP22 and IGP30 were associated with a higher risk of COVID-19 hospitalization and severity. Two (IGP2 and IGP77) and five (IGP10, IGP14, IGP34, IGP36, and IGP50) IgG N-glycosylation traits were causally associated with a decreased risk of COVID-19 hospitalization and severity, respectively. Sensitivity analyses did not identify any horizontal pleiotropy.ConclusionsOur study provides evidence that genetically elevated IgG N-glycosylation traits may have a causal effect on diverse COVID-19 outcomes. Our findings have potential implications for developing targeted interventions to improve COVID-19 outcomes by modulating IgG N-glycosylation levels.
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| 22. |
- Ma, Tengfei, et al.
(författare)
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Distinguishing Bipolar Depression from Major Depressive Disorder Using fNIRS and Deep Neural Network
- 2020
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Ingår i: Progress In Electromagnetics Research. - : The Electromagnetics Academy. - 1070-4698 .- 1559-8985. ; 169, s. 73-86
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Tidskriftsartikel (refereegranskat)abstract
- A variety of psychological scales are utilized at present as the most important basis for clinical diagnosis of mood disorders. An experienced psychiatrist assesses and diagnoses mood disorders based on clinical symptoms and relevant assessment scores. This symptom based clinical criterion is limited by the psychiatrist's experience. In practice, it is difficult to distinguish the patients with bipolar disorder with depression episode (bipolar depression, BD) from those with major depressive disorder (MDD). The functional near-infrared spectroscopy (fNIRS) technology is commonly used to perceive the emotions of a human. It measures the hemodynamic parameters of the brain, which correlate with cerebral activation. Here, we propose a machine learning classification method based on deep neural network for the brain activations of mood disorders. Large time scale connectivity is determined using an attention long short term memory neural network and short-time feature information are considered using the InceptionTime neural network in this method. Our combined method is referred to as AttentionLSTM-InceptionTime (ALSTMIT). We collected fNIRS data of 36 MDD patients and 48 BD patients who were in the depressed state. All the patients were monitored by fNIRS during conducting the verbal fluency task (VFT). We trained the model with the ALSTMIT network. The algorithm can distinguish the two types of patients effectively: the average accuracy of classification on the test set can reach 96.2% stably. The classification can provide an objective diagnosis tool for clinicians, and this algorithm may be critical for the early detection and precise treatment for the patients with mood disorders.
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| 23. |
- Machiela, Mitchell J., et al.
(författare)
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Characterization of Large Structural Genetic Mosaicism in Human Autosomes
- 2015
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Ingår i: American Journal of Human Genetics. - : Elsevier BV. - 0002-9297 .- 1537-6605. ; 96:3, s. 487-497
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Tidskriftsartikel (refereegranskat)abstract
- Analyses of genome-wide association study (GWAS) data have revealed that detectable genetic mosaicism involving large (>2 Mb) structural autosomal alterations occurs in a fraction of individuals. We present results for a set of 24,849 genotyped individuals (total GWAS set II [TGSII]) in whom 341 large autosomal abnormalities were observed in 168 (0.68%) individuals. Merging data from the new TGSII set with data from two prior reports (the Gene-Environment Association Studies and the total GWAS set I) generated a large dataset of 127,179 individuals; we then conducted a meta-analysis to investigate the patterns of detectable autosomal mosaicism (n = 1,315 events in 925 [0.73%] individuals). Restricting to events >2 Mb in size, we observed an increase in event frequency as event size decreased. The combined results underscore that the rate of detectable mosaicism increases with age (p value = 5.5 x 3 10(-31)) and is higher in men (p value = 0.002) but lower in participants of African ancestry (p value = 0.003). In a subset of 47 individuals from whom serial samples were collected up to 6 years apart, complex changes were noted over time and showed an overall increase in the proportion of mosaic cells as age increased. Our large combined sample allowed for a unique ability to characterize detectable genetic mosaicism involving large structural events and strengthens the emerging evidence of non-random erosion of the genome in the aging population.
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| 24. |
- Machiela, Mitchell J, et al.
(författare)
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Female chromosome X mosaicism is age-related and preferentially affects the inactivated X chromosome
- 2016
-
Ingår i: Nature Communications. - : Nature Publishing Group. - 2041-1723. ; 7
-
Tidskriftsartikel (refereegranskat)abstract
- To investigate large structural clonal mosaicism of chromosome X, we analysed the SNP microarray intensity data of 38,303 women from cancer genome-wide association studies (20,878 cases and 17,425 controls) and detected 124 mosaic X events >2 Mb in 97 (0.25%) women. Here we show rates for X-chromosome mosaicism are four times higher than mean autosomal rates; X mosaic events more often include the entire chromosome and participants with X events more likely harbour autosomal mosaic events. X mosaicism frequency increases with age (0.11% in 50-year olds; 0.45% in 75-year olds), as reported for Y and autosomes. Methylation array analyses of 33 women with X mosaicism indicate events preferentially involve the inactive X chromosome. Our results provide further evidence that the sex chromosomes undergo mosaic events more frequently than autosomes, which could have implications for understanding the underlying mechanisms of mosaic events and their possible contribution to risk for chronic diseases.
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| 25. |
- Meng, Wen-Jian, et al.
(författare)
-
Microsatellite instability did not predict individual survival in sporadic stage II and III rectal cancer patients
- 2007
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Ingår i: Oncology. - : S. Karger AG. - 0890-9091 .- 0030-2414 .- 1423-0232. ; 72:1-2, s. 82-88
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: Tumors with high-frequency microsatellite instability (MSI-H) have unique biological behavior and the predictive role of microsatellite instability (MSI) status on survival of colorectal cancer is still debated. The prognostic significance of MSI status in sporadic stage II and III rectal cancer patients needs to be more precisely defined. So we investigated the relationship between MSI status and clinicopathological features and prognosis in these patients. Methods: DNAs from fresh-frozen paired samples of tumors and corresponding normal tissue from 128 stage II and III rectal cancer patients were analyzed for MSI by PCR amplification using markers recommended by a National Cancer Institute workshop on MSI. To assess prognostic significance, Cox proportional hazards modeling was used. Results: Twelve (9.3%) tumors in our study were MSI-H, 28 (21.9%) were low-frequency MSI (MSI-L) and 88 (68.8%) were microsatellite stable (MSS). Most of the MSI-H tumors compared with MSI-L and MSS tumors were found in female patients (p = 0.031), had mucinous histology (p = 0.023), high grade of differentiation (p = 0.002) and high level of preoperative serum carcinoembryonic antigen (p = 0.005). Rectal cancer patients with MSI-H did not show a better clinical outcome than those with MSI-L/MSS, neither in all cases (p = 0.986) nor in stage II and stage III disease analyzed separately (p = 0.705 and p = 0.664, respectively). Conclusions: Data provided here demonstrated there was high incidence of MSI-H and MSI was not a prognostic factor in sporadic stage II and III rectal cancers from the Chinese Han population included in this study. Tumor stage is more suitable than MSI status for prediction of individual survival in sporadic stage II and III rectal cancer patients. Copyright © 2007 S. Karger AG.
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| 26. |
- Meng, Wen-Jian, et al.
(författare)
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Novel mutations and sequence variants in exons 3-9 of human T Cell Factor-4 gene in sporadic rectal cancer patients stratified by microsatellite instability
- 2007
-
Ingår i: World Journal of Gastroenterology. - 1007-9327 .- 2219-2840. ; 13:27, s. 3747-3751
-
Tidskriftsartikel (refereegranskat)abstract
- Aim: To establish the role of human T Cell Factor-4 (hTCF-4) gene exons 3-9 mutation status in association with sporadic rectal cancer with microsatellite instability (MSI). Methods: Microsatellite markers were genotyped in 93 sporadic rectal cancer patients. Eleven cases were found to be high-frequency MSI (MSI-H). Sequence analysis of the coding region of the exons 3-9 of hTCF-4 gene was carried out for the 11 MSI-H cases and 10 controls (5 microsatellite stability (MSS) cases and 5 cases with normal mucosa). The sequencing and MSI identification were used. Results: Several novel mutations and variants were revealed. In exon 4, one is a 4-position continuous alteration which caused amino acid change from Q131T and S132I (391insA, 392 G > A, 393 A > G and 395delC) and another nucleotide deletion (395delC) is present in MSI-H cases (5/10 and 4/10, respectively) but completely absent in the controls. Conclusion: Novel mutations in exon 4 of hTCF-4 gene were revealed in this study, which might be of importance in the pathogenesis of sporadic rectal cancer patients with MSI-H. © 2007 WJG. All rights reserved.
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| 27. |
- Nuala, M.Caffrey, et al.
(författare)
-
Structural and electronic properties of Li-intercalated graphene on SiC(0001)
- 2016
-
Ingår i: Physical Review B: covering condensed matter and materials physics. - : American Physical Society. - 2469-9950. ; 93:19, s. 195421-1-195421-9
-
Tidskriftsartikel (refereegranskat)abstract
- We investigate the structural and electronic properties of Li-intercalated monolayer graphene on SiC(0001) using combined angle-resolved photoemission spectroscopy and first-principles density functional theory. Li intercalates at room temperature both at the interface between the buffer layer and SiC and between the two carbon layers. The graphene is strongly n-doped due to charge transfer from the Li atoms and two pi bands are visible at the (K) over bar point. After heating the sample to 300 degrees C, these pi bands become sharp and have a distinctly different dispersion to that of Bernal-stacked bilayer graphene. We suggest that the Li atoms intercalate between the two carbon layers with an ordered structure, similar to that of bulk LiC6. An AA stacking of these two layers becomes energetically favourable. The pi bands around the (K) over bar point closely resemble the calculated band structure of a C6LiC6 system, where the intercalated Li atoms impose a superpotential on the graphene electronic structure that opens gaps at the Dirac points of the two pi cones.
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| 28. |
- Wang, Yangong, et al.
(författare)
-
Exome sequencing reveals genetic heterogeneity and clinically actionable findings in children with cerebral palsy
- 2024
-
Ingår i: NATURE MEDICINE. - 1078-8956 .- 1546-170X. ; 30, s. 1395-1405
-
Tidskriftsartikel (refereegranskat)abstract
- Cerebral palsy (CP) is the most common motor disability in children. To ascertain the role of major genetic variants in the etiology of CP, we conducted exome sequencing on a large-scale cohort with clinical manifestations of CP. The study cohort comprised 505 girls and 1,073 boys. Utilizing the current gold standard in genetic diagnostics, 387 of these 1,578 children (24.5%) received genetic diagnoses. We identified 412 pathogenic and likely pathogenic (P/LP) variants across 219 genes associated with neurodevelopmental disorders, and 59 P/LP copy number variants. The genetic diagnostic rate of children with CP labeled at birth with perinatal asphyxia was higher than the rate in children without asphyxia (P = 0.0033). Also, 33 children with CP manifestations (8.5%, 33 of 387) had findings that were clinically actionable. These results highlight the need for early genetic testing in children with CP, especially those with risk factors like perinatal asphyxia, to enable evidence-based medical decision-making. Using exome sequencing data from one of the largest cohorts of children with cerebral palsy, the genetic diagnostic rates of single-nucleotide and copy number variants were assessed and a sizeable fraction found to be clinically actionable.
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| 29. |
- Wang, Zhaoming, et al.
(författare)
-
Imputation and subset-based association analysis across different cancer types identifies multiple independent risk loci in the TERT-CLPTM1L region on chromosome 5p15.33
- 2014
-
Ingår i: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 23:24, s. 6616-6633
-
Tidskriftsartikel (refereegranskat)abstract
- Genome-wide association studies (GWAS) have mapped risk alleles for at least 10 distinct cancers to a small region of 63 000 bp on chromosome 5p15.33. This region harbors the TERT and CLPTM1L genes; the former encodes the catalytic subunit of telomerase reverse transcriptase and the latter may play a role in apoptosis. To investigate further the genetic architecture of common susceptibility alleles in this region, we conducted an agnostic subset-based meta-analysis (association analysis based on subsets) across six distinct cancers in 34 248 cases and 45 036 controls. Based on sequential conditional analysis, we identified as many as six independent risk loci marked by common single-nucleotide polymorphisms: five in the TERT gene (Region 1: rs7726159, P = 2.10 × 10(-39); Region 3: rs2853677, P = 3.30 × 10(-36) and PConditional = 2.36 × 10(-8); Region 4: rs2736098, P = 3.87 × 10(-12) and PConditional = 5.19 × 10(-6), Region 5: rs13172201, P = 0.041 and PConditional = 2.04 × 10(-6); and Region 6: rs10069690, P = 7.49 × 10(-15) and PConditional = 5.35 × 10(-7)) and one in the neighboring CLPTM1L gene (Region 2: rs451360; P = 1.90 × 10(-18) and PConditional = 7.06 × 10(-16)). Between three and five cancers mapped to each independent locus with both risk-enhancing and protective effects. Allele-specific effects on DNA methylation were seen for a subset of risk loci, indicating that methylation and subsequent effects on gene expression may contribute to the biology of risk variants on 5p15.33. Our results provide strong support for extensive pleiotropy across this region of 5p15.33, to an extent not previously observed in other cancer susceptibility loci.
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| 30. |
- Watcharinyanon, Somsakul, et al.
(författare)
-
Changes in structural and electronic properties of graphene grown on 6H-SiC(0001) induced by Na deposition
- 2012
-
Ingår i: Journal of Applied Physics. - : American Institute of Physics (AIP). - 0021-8979 .- 1089-7550. ; 111:8, s. 083711-
-
Tidskriftsartikel (refereegranskat)abstract
- The effects of Na deposited on monolayer graphene on SiC(001) were investigated by synchrotron-based photoelectron spectroscopy and angle resolved photoelectron spectroscopy. The experimental results show that Na prefers to adsorb on the graphene layer after deposition at room temperature. Nonetheless, part of the Na atoms are able to intercalate in between the graphene and the buffer layer and some go even further into the substrate interface as indicated by the shift of the bulk SiC component in the C 1s and Si 2p core level spectra. The ARPES spectrum exhibits a lowering of the Dirac point indicating increased n-type doping of the monolayer graphene induced by the deposited Na atoms. Upon subsequently heating the sample, we found that a slightly elevated temperature is essential in order to promote Na intercalation. A fully Na intercalation at the graphene-SiC interface is obtained after heating at a temperature of about 75 degrees C. The intercalated Na decouples the buffer layer and transforms it into a second graphene layer so two pi-bands are observed in the ARPES spectra. Interestingly, the two bands show different locations of the Dirac point but both exhibit linear dispersion in the vicinity of the (K) over bar point and not the hyperbolic dispersion observed for AB stacked bi-layer graphene. When heating the sample to about 125 degrees C or higher, Na is found to leave the interface and the second graphene layer is transformed back to the carbon buffer layer.
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| 31. |
- Watcharinyanon, Somsakul, et al.
(författare)
-
Soft X-ray Exposure Promotes Na Intercalation in Graphene Grown on Si-Face SiC
- 2015
-
Ingår i: Materials. - : MDPI AG. - 1996-1944. ; 8:8, s. 4768-4777
-
Tidskriftsartikel (refereegranskat)abstract
- An investigation of how electron/photon beam exposures affect the intercalation rate of Na deposited on graphene prepared on Si-face SiC is presented. Focused radiation from a storage ring is used for soft X-ray exposures while the electron beam in a low energy electron microscope is utilized for electron exposures. The microscopy and core level spectroscopy data presented clearly show that the effect of soft X-ray exposure is significantly greater than of electron exposure, i.e., it produces a greater increase in the intercalation rate of Na. Heat transfer from the photoelectrons generated during soft X-ray exposure and by the electrons penetrating the sample during electron beam exposure is suggested to increase the local surface temperature and thus the intercalation rate. The estimated electron flux density is 50 times greater for soft X-ray exposure compared to electron exposure, which explains the larger increase in the intercalation rate from soft X-ray exposure. Effects occurring with time only at room temperature are found to be fairly slow, but detectable. The graphene quality, i.e., domain/grain size and homogeneity, was also observed to be an important factor since exposure-induced effects occurred more rapidly on a graphene sample prepared in situ compared to on a furnace grown sample.
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| 32. |
- Watcharinyanon, Somsakul, et al.
(författare)
-
Ytterbium oxide formation at the graphene-SiC interface studied by photoemission
- 2013
-
Ingår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films. - : American Vacuum Society. - 0734-2101 .- 1520-8559. ; 31:2
-
Tidskriftsartikel (refereegranskat)abstract
- Synchrotron-based core level and angle resolved photoemission spectroscopy was used to study the formation of ytterbium (Yb) oxide at the graphene-SiC substrate interface. Oxide formation at the interface was accomplished in two steps, first intercalation of Yb into the interface region and then oxygen exposure while heating the sample at 260 degrees C to oxidize the Yb. After these processes, core level results revealed the formation of Yb oxide at the interface. The Yb 4f spectrum showed upon oxidation a clear valence change from Yb2+ to Yb3+. After oxidation the spectrum was dominated by emission from oxide related Yb3+ states and only a small contribution from silicide Yb2+ states remained. In addition, the very similar changes observed in the oxide related components identified in the Si 2p and Yb 4f spectra after oxidation and after subsequent heating suggested formation of a Si-Yb-O silicate at the interface. The electronic band structure of graphene around the (K) over bar -point was upon Yb intercalation found to transform from a single pi band to two pi bands. After Yb oxide formation, an additional third pi band was found to appear. These pi bands showed different locations of the Dirac point (E-D), i.e., two upper bands with E-D around 0.4 eV and a lower band with E-D at about 1.5 eV below the Fermi level. The appearance of three pi-bands is attributed to a mixture of areas with Yb oxide and Yb silicide at the interface.
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| 33. |
- Xia, Chao
(författare)
-
Characterizations of as grown and functionalized epitaxial graphene grown on SiC surfaces
- 2015
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The superior electronic and mechanical properties of Graphene have promoted graphene to become one of the most promising candidates for next generation of electronic devices. Epitaxial growth of graphene by sublimation of Si from Silicon Carbide (SiC) substrates avoids the hazardous transfer process for large scale fabrication of graphene based electronic devices. Moreover, the operation conditions can potentially be extended to high temperatures, voltages and frequencies. This thesis is focused on characterizations of as grown and functionalized epitaxial graphene grown on both Si-face and C-face SiC. Synchrotron radiation-based techniques are employed for detailed investigations of the electronic properties and surface morphology of as grown and functionalized graphene.Large area and homogeneous monolayer (ML) graphene has been possible to grow on SiC(0001) substrates by sublimation, but efforts to obtain multilayer graphene of similar quality have been in vain. A study of the transport behavior of silicon atoms through carbon layers was therefore performed for the purpose to gain a better understanding of the growth mechanism of graphene on Si-face SiC. It showed that a temperature of about 800°C is required for Si intercalation into the interface to take place. Intercalation of Si was found to occur only via defects and domain boundaries which probably is the reason to the limited growth of multilayer graphene. Annealing at 1000-1100°C induced formation of SiC on the surface and after annealing above 1200°C Si started to de-intercalate and desorb/sublimate.Different alkali metals were found to affect graphene grown in SiC quite differently. Li started to intercalate already at room temperature by creating cracks and defects, while K, Rb and Cs were found unable to intercalate into the graphene/SiC interface. Effects induced by the alkali metal Na on graphene grown on both Si-face and C-face SiC were therefore studies. For the Si-face, partial intercalation of Na through graphene was observed on both 1 ML and 2 ML areas directly after Na deposition. Annealing at a temperature of about 75°C strongly promoted Na intercalation at the interface. The intercalation was confirmed to start at domain boundaries between 1 ML and 2 ML areas and at stripes/streaks on the 1 ML areas. Higher annealing temperature resulted in desorption of Na from the sample surface. Also for C-face graphene, a strong n-type doping was observed directly after Na deposition. Annealing at temperatures from around 120 to 300 °C was here found to result in a considerable π-band broadening, interpreted to indicate penetration of Na in between the graphene layers and at the graphene SiC interface.The thermal stability of graphene based electronic devices can depend on the choice of contact material. Studies of the stability and effects induced by two commonly used metals (Pt and Al) on Si-face graphene were carried out after deposition and after subsequent annealing at different temperatures. Both Al and Pt were found to be good contact materials at room temperature. Annealing at respectively ~400 ºC and ~ 800 ºC was found to trigger intercalation of Al and Pt into the graphene/SiC interface, and induce quasi-free-standing bilayer electronic properties. Contacts of Pt can thus withstand higher temperatures than Al contacts. For Al inhomogeneous islands of different ordered phases were observed to form on the surface during annealing, while this was not the case for Pt. The initial single π-band structure was in the Al case restored after annealing at ~1200 ºC although some Al remained detectable from the sample. For Pt, the bilayer graphene electronic properties induced by intercalation were thermally stable up to 1200ºC. In the case of Al the stability and effects induced on C-face graphene were also investigated for comparison, and significant differences were revealed. An ordered Al-Si-C compound was found to form after annealing at temperatures between ca. 500ºC and 700ºC. Formation of this compound was accompanied with a large reduction of graphene in the surface region. Annealing at temperatures above 800°C resulted in a gradual decomposition of this compound and regrowth of graphene. No Al signal could be detected after annealing C-face graphene at 1000°C.Graphene grown on C-face SiC has attracted high interest since its mobility has been reported to be one order of magnitude higher compared to Si-face graphene. C-face graphene has moreover been claimed to be fundamentally different compared to Si-face graphene. A rotational disorder between adjacent graphene layers has been suggested that effectively decouples the graphene layers and result in monolayer electronic properties of multilayer C-face graphene. The domain/grain size is typically much smaller for C-face graphene and the number of graphene layers less uniform than on Si-face graphene. Using LEEM and micro-LEED we showed that there is no rotational disorder between adjacent layers within the domains/grains but that they had different azimuthal orientations. Using nano-APRES, we recently also revealed that multilayer Cface graphene show multiple π-bands and Bernal stacking, similar to multilayer Si-face graphene.
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| 34. |
- Xia, Chao, et al.
(författare)
-
Detailed studies of Na intercalation on furnace-grown graphene on 6H-SiC(0001)
- 2013
-
Ingår i: Surface Science. - : Elsevier. - 0039-6028 .- 1879-2758. ; 613, s. 88-94
-
Tidskriftsartikel (refereegranskat)abstract
- The effects induced by Na deposited on furnace grown graphene on SiC(0001) and after subsequent annealing are investigated using LEEM, mu-LEED, mu-PES and XPEEM. Intercalation in between carbon layers and at the interface is observed to occur both on the 1 ML and 2 ML areas directly after Na deposition. Annealing at a temperature around 100 degrees C is found to strongly promote Na intercalation. Exposure to the electron beam or the focused synchrotron radiation in the LEEM/XPEEM is also found to promote the intercalation, which is confirmed to begin at domain boundaries between the 1 ML and 2 ML areas, and also as stripe/streak-like features on the 1 ML areas. The XPEEM data show Na adsorption on the surface and intercalation at the interface to be quite non-uniform. When annealing at higher temperatures Na starts to de-intercalate and leave the sample, but Na is still detectable on the sample after annealing at 240 degrees C.
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| 35. |
- Xia, Chao, et al.
(författare)
-
Effects of Al on epitaxial graphene grown on 6H-SiC(0001)
- 2014
-
Ingår i: Materials Research Express. - : Institute of Physics Publishing (IOPP). - 2053-1591. ; 1:1, s. 1-13
-
Tidskriftsartikel (refereegranskat)abstract
- Aluminum was deposited on epitaxial monolayer-grown graphene on SiC(0001). The effects of annealing up to 1200 °C on the surface and interface morphology, chemical composition, and electron band structure were analyzed in situ by synchrotron-based techniques at the MAX Laboratory. After heating at around 400 °C, Al islands or droplets are observed on the surface and the collected Si 2p, Al 2p, and C 1s core levels spectra indicate Al intercalation at the graphene SiC interface. Also, the original single Ï€ -band splits into two, indicating decoupling of the carbon buffer layer and the formation of a quasi-free-standing bilayer-like electronic structure. Further heating at higher temperatures from 700 to 900 °C yields additional chemical reactions. Broader core level spectra are then observed and clear changes in the Ï€ -bands near the Dirac point are detected. More electron doping was detected at this stage since one of the Ï€ -bands has shifted to about 1.1 eV below the Fermi level. Different ordered phases of (7x7), (4x4), (1x1)Al , and (1x1)G were also observed on the surface in this temperature range. The original single Ï€ π-band was restored after heating at ~1200°C, although an Al signal was still able to be detected.
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| 36. |
- Xia, Chao, et al.
(författare)
-
Effects of aluminum on epitaxial graphene grown on C-face SiC
- 2015
-
Ingår i: Journal of Applied Physics. - : American Institute of Physics (AIP). - 0021-8979 .- 1089-7550. ; 117:19
-
Tidskriftsartikel (refereegranskat)abstract
- The effects of Al layers deposited on graphene grown on C-face SiC substrates are investigated before and after subsequent annealing using low energy electron diffraction (LEED), photoelectron spectroscopy, and angle resolved photoemission. As-deposited layers appear inert. Annealing at a temperature of about 400 degrees C initiates migration of Al through the graphene into the graphene/SiC interface. Further annealing at temperatures from 500 degrees C to 700 degrees C induces formation of an ordered compound, producing a two domain root 7 x root 7R19 degrees LEED pattern and significant changes in the core level spectra that suggest formation of an Al-Si-C compound. Decomposition of this compound starts after annealing at 800 degrees C, and at 1000 degrees C, Al is no longer possible to detect at the surface. On Si-face graphene, deposited Al layers did not form such an Al-Si-C compound, and Al was still detectable after annealing above 1000 degrees C.
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| 37. |
- Xia, Chao, 1986-, et al.
(författare)
-
Effects of rhenium on graphene grown on SiC(0001)
- 2018
-
Ingår i: Journal of Electron Spectroscopy and Related Phenomena. - : Elsevier. - 0368-2048 .- 1873-2526. ; 222, s. 117-121
-
Tidskriftsartikel (refereegranskat)abstract
- We study the effects of Rhenium (Re) deposited on epitaxial monolayer graphene grown on SiC(0001) and after subsequent annealing at different temperatures, by performing high resolution photoelectron spectroscopy (PES) and angle resolved photoelectron spectroscopy (ARPES). The graphene-Re system is found to be thermally stable. While no intercalation or chemical reaction of the Re is detected after deposition and subsequent annealing up to 1200 degrees C, a gradual decrease in the binding energy of the Re 4f doublet is observed. We propose that a larger mobility of the Re atoms with increasing annealing temperature and hopping of Re atoms between different defective sites on the graphene sample could induce this decrease of Re 4f binding energy. This is corroborated by first principles density functional theory (DFT) calculations of the Re core-level binding energy shift. No change in the doping or splitting of the initial monolayer graphene electronic band structure is observed after Re deposition and annealing up to 1200 degrees C, only a broadening of the bands. (C) 2017 Elsevier B.V. All rights reserved.
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| 38. |
- Xia, Chao, et al.
(författare)
-
High thermal stability quasi-free-standing bilayer graphene formed on 4H-SiC(0001) via platinum intercalation
- 2014
-
Ingår i: Carbon. - : Elsevier BV. - 0008-6223 .- 1873-3891. ; 79, s. 631-635
-
Tidskriftsartikel (refereegranskat)abstract
- Influences on electronic structure induced by platinum (Pt) deposited on monolayer graphene grown on SiC(0001) are investigated by photoelectron spectroscopy (PES), selected area low energy electron diffraction (mu-LEED) and angle resolved photoelectron spectroscopy (ARPES) techniques at the MAX Laboratory. Stable monolayer graphene electronic properties are observed after Pt deposition and after annealing at temperatures below 600 degrees C. At >= 600 degrees C platinum silicide forms at the graphene/SiC interface. Annealing at 900 degrees C results in an efficient decoupling of the carbon buffer layer from the SiC substrate and transformation into a second graphene layer. At this stage a quasi-free standing bi-layer graphene sample is obtained. The new superstructure spots then appearing in mu-LEED pattern suggest formation of an ordered platinum silicide at the interface. This silicide is found to be stable even after annealing at temperature up to 1200 degrees C. (C) 2014 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).
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| 39. |
- Xia, Chao, et al.
(författare)
-
Si intercalation/deintercalation of graphene on 6H-SiC(0001)
- 2012
-
Ingår i: Physical Review B. Condensed Matter and Materials Physics. - : American Physical Society. - 1098-0121 .- 1550-235X. ; 85:4, s. 045418-
-
Tidskriftsartikel (refereegranskat)abstract
- The intercalation and deintercalation mechanisms of Si deposited on monolayer graphene grown on SiC(0001) substrates and after subsequent annealing steps are investigated using low-energy electron microscopy (LEEM), photoelectron spectroscopy (PES), and micro-low-energy electron diffraction (mu-LEED). After Si deposition on samples kept at room temperature, small Si droplets are observed on the surface, but no intercalation can be detected. Intercalation is revealed to occur at an elevated temperature of about 800. C. The Si is found to migrate to the interface region via defects and domain boundaries. This observation may provide an answer to the problem of controlling homogeneous bi-/multilayer graphene growth on nearly perfect monolayer graphene samples prepared on SiC(0001). Likewise, Si penetrates more easily small monolayer graphene domains because of the higher density of domain boundaries. Upon annealing at 1000-1100 degrees C, formation of SiC on the surface is revealed by the appearance of a characteristic surface state located at about 1.5 eV below the Fermi level. A streaked mu-LEED pattern is also observed at this stage. The SiC formed on the surface is found to decompose again after annealing at temperatures higher than 1200 degrees C.
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| 40. |
- Xia, Kai, et al.
(författare)
-
A Cloud-based Disassembly Planning Approach towards Sustainable Management of WEEE
- 2015
-
Ingår i: 2015 IEEE 12TH INTERNATIONAL CONFERENCE ON E-BUSINESS ENGINEERING (ICEBE). - : IEEE. - 9781467380027 ; , s. 203-208
-
Konferensbidrag (refereegranskat)abstract
- Waste Electrical and Electronic Equipment (WEEE) is becoming an important and challenging waste stream in terms of quantity and toxicity. Developing technical solutions for sustainable management of WEEE is becoming a global trend. Disassembly planning plays an important role in End-of-Life treatment of WEEE. Effective disassembly planning can improve the recovery rate and reduce the environmental impact of WEEE significantly. Targeting sustainable WEEE management, this paper aims to propose a cloud-based approach for disassembly planning. The approach provides a comprehensive and standardized service-oriented environment for distributed information sharing, disassembly modeling, evaluation and optimization.
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| 41. |
- Xia, K., et al.
(författare)
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A Q-learning based selective disassembly planning service in the cloud based remanufacturing system for WEEE
- 2014
-
Ingår i: ASME 2014 International Manufacturing Science and Engineering Conference, MSEC 2014 Collocated with the JSME 2014 International Conference on Materials and Processing and the 42nd North American Manufacturing Research Conference. - : ASME Press. - 9780791845806
-
Konferensbidrag (refereegranskat)abstract
- Cloud based approach for remanufacturing is becoming a new technical solution for sustainable management of Waste Electrical and Electronic Equipment (WEEE). This paper presents a service-oriented framework of a Cloud Based Remanufacturing System (CBRS) for WEEE. In remanufacturing of WEEE, disassembly plays an important role. However, complete disassembly is rarely an ideal solution due to the high disassembly cost, with the increasing customization and diversity, and more complex assembly processes of Electrical and Electronic Equipment (EEE). Selective disassembly focusing on disassembling only a few selected components is a better choice. In this paper, a Q-Learning based Selective Disassembly Planning (QL-SDP) approach embedded with a multi-criteria decision making model is developed. The multi-criteria decision making model is built according to the legislative and economic considerations of specific stakeholders of WEEE. And the QLSDP approach is used to achieve optimized selective disassembly planning. An implementation example has been used to verify and demonstrate the effectiveness and robustness of the approach. The developed QL-SDP approach is designed as a service implemented in the presented CBRS for WEEE.
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| 42. |
- Xia, K., et al.
(författare)
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A Semantic Information Services Framework for Sustainable WEEE Management Toward Cloud-Based Remanufacturing
- 2015
-
Ingår i: Journal of manufacturing science and engineering. - : ASME International. - 1087-1357 .- 1528-8935. ; 137:6
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Tidskriftsartikel (refereegranskat)abstract
- Sustainable management of waste electrical and electronic equipment (WEEE) has attracted escalating concerns of researchers and industries. Closer information linking among the participants in the products's lifecycle should take place. How to interoperate among the distributed and heterogeneous information systems of various participants is a challenge faced. Targeting the cloud-based remanufacturing, this article aims to develop a semantic information services framework for sustainable WEEE management. In the proposed framework, an ontology based approach is developed to integrate and represent the lifecycle information from multiple local data sources within an information services provider. Meanwhile, a semantic information services management platform is introduced for the advertisement, matchmaking and retrieval of semantic information services. Some relevant techniques used to build the framework are introduced extensively. A demonstration case study on waste LCD TV is used to illustrate the effectiveness and significance of the proposed framework.
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| 43. |
- Xia, K., et al.
(författare)
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A semantic information services framework for sustainable WEEE management toward cloud-based remanufacturing
- 2018
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Ingår i: Sustainable Manufacturing and Remanufacturing Management. - Cham : Springer International Publishing. - 9783319734880 - 9783319734873 ; , s. 235-257
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Sustainable management of Waste Electrical and Electronic Equipment (WEEE) has attracted escalating concerns of researchers and industries. Closer information linking among the participants in the products' lifecycle should take place. How to interoperate among the distributed and heterogeneous information systems of various participants is a challenge faced. Targeting the cloud-based remanufacturing, this article aims to develop a semantic information services framework for sustainable WEEE management. In the proposed framework, an ontology-based approach is developed to integrate and represent the lifecycle information from multiple local data sources within an information services provider. Meanwhile, a semantic information services management platform is introduced for the advertisement, matchmaking, and retrieval of semantic information services. Some relevant techniques used to build the framework are introduced extensively. A demonstration case study on waste LCD TV is used to illustrate the effectiveness and significance of the proposed framework.
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| 44. |
- Xia, K., et al.
(författare)
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A simplified teaching-learning-based optimization algorithm for disassembly sequence planning
- 2013
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Ingår i: Proceedings - 2013 IEEE 10th International Conference on e-Business Engineering, ICEBE 2013. - : IEEE. - 9780769551111 ; , s. 393-398
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Konferensbidrag (refereegranskat)abstract
- Disassembly plays an important role in recovery and remanufacturing of Waste Electrical and Electronic Equipment (WEEE). A novel Simplified Teaching-Learning-Based Optimization (STLBO) algorithm is proposed for optimization of Disassembly Sequence Planning (DSP). The proposed STLBO is on the basis of a teaching-learning-based optimization method which is a new population based meta-heuristic algorithms. In the proposed STLBO algorithm, three operators are designed namely Feasible Solution Generator (FSG), Teacher Phase Operator (TPO) and Learner Phase Operator (LPO). The proposed algorithm is successfully tested against previous best known solutions for a set of public benchmarks.
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| 45. |
- Xia, Yangyang, et al.
(författare)
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Prediction of bending strength of glass fiber reinforced methacrylate-based pipeline UV-CIPP rehabilitation materials based on machine learning
- 2023
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Ingår i: Tunnelling and Underground Space Technology. - : Elsevier. - 0886-7798 .- 1878-4364. ; 140
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Tidskriftsartikel (refereegranskat)abstract
- Ultraviolet cured-in-place-pipe (UV-CIPP) materials are commonly used in trenchless pipeline rehabilitation. Their bending strength is a crucial indicator to evaluate the curing quality. Studies show that this indicator is affected by multiple factors, including the curing time, UV lamp curing power, curing distance, and material thickness. Laboratory experiments have limitations in analyzing the effect of multiple factors on the bending strength of UV-CIPP materials and quantitatively predicting the optimum curing parameters. Aiming at resolving these shortcomings, resolve machine learning techniques were applied to predict the bending strength. In this regard, the surface curing reaction temperature monitoring data and three-point bending data of 30 groups of UV-CIPP material under the influence of different curing parameters were used as a dataset to predict the bending strength of UV-CIPP material. The results show that the influence degree of each factor on the bending strength of the UV-CIPP material, from high to low, is as follows: UV lamp power (−0.439), the temperature at the illuminated side (−0.392), curing time (−0.323), the temperature at the back side (−0.233), curing distance (0.143) and material thickness (−0.140). The best penalty parameter c (44.435) and width g (0.072) of the kernel function in the support vector machine (SVM) model were obtained using the genetic algorithm (GA) optimization, and the results were compared with the grey wolf optimizer (GWO) and particle swarm optimization (PSO). The performed analyses revealed that the developed GA-SVM model exhibits the best prediction results compared to other machine learning algorithms. The optimum bending strength of the UV-CIPP material used in this test is 294.77 MPa, which corresponds to the curing time, UV lamp power, curing distance, material thickness, light side temperature, and back side temperature of 7.59 min, 157.33 mW/cm2, 189.99 mm, 4.38 mm, 79.49 °C, and 76.59 °C, respectively.
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| 46. |
- Xia, Ziqian, et al.
(författare)
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A meta-analysis of the relationship between climate change experience and climate change perception
- 2022
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Ingår i: Environmental Research Communications. - : IOP Publishing. - 2515-7620. ; 4:10
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Tidskriftsartikel (refereegranskat)abstract
- Will climate change experience shape people's climate change perception? To examine the evidence, we performed a pre-registered meta-analysis using data from 302 studies, covering 351,378 observations. Our results find that climate change experience only has a weak positive correlation with climate change awareness in general (r = 0.098, 95% CI 0.0614, 0.1348), and the effect sizes vary considerably across different climate events. General hazard and temperature anomalies experiences have significant correlations, but other events exhibit no or neglectable effects. The moderator analysis showed that self-reported studies result in higher correlations, whereas studies based on victims' actual experiences report lower effect sizes. Our study suggests that people's climate change experiences may not be effective in shaping their awareness of climate change, which is likely due to people's attribution style and adaptability. The importance of proactive education thus is further emphasized to raise the awareness of climate change.
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| 47. |
- Xu, Jianhua, et al.
(författare)
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A Variant of the Autophagy-Related 5 Gene is Associated with Child Cerebral Palsy
- 2017
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Ingår i: Frontiers in Cellular Neuroscience. - : Frontiers Media SA. - 1662-5102. ; 18
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Tidskriftsartikel (refereegranskat)abstract
- Cerebral palsy (CP) is a major cause of childhood disability in developed and developing countries, but the pathogenic mechanisms of CP development remain largely unknown. Autophagy is a highly conserved cellular self-digestion of damaged organelles and dysfunctional macromolecules. Growing evidence suggests that autophagy-related gene 5 (ATG5)-dependent autophagy is involved in neural development, neuronal differentiation, and neurological degenerative diseases. The aim of this study was to analyze ATG5 protein expression and gene polymorphisms in Chinese patients with CP and to evaluate the importance of ATG5 in the development of CP. Five polymorphisms from different regions of the ATG5 gene (rs510432, rs3804338, rs573775, rs2299863, and rs6568431) were analyzed in 715 CP patients and 658 controls using MassARRAY. Of these, 58 patients and 56 controls were selected for measurement of plasma ATG5 level using ELISA. The relevance of disease-associated SNPs was evaluated using the SHEsis program. We identified a significant association between rs6568431 and CP (OR = 1.388, 95% CI = 1.173∼1.643, Pallele = 0.0005, Pgenotype = 0.0015). Subgroup analysis showed a highly significant association of rs6568431 with spastic CP (n = 468, OR = 1.511, 95% CI = 1.251∼1.824, Pallele = 8.50e−005, Pgenotype = 1.57e−004) and spastic quadriplegia (OR = 1.927, 95% CI = 1.533∼2.421, Pallele = 7.35e−008, Pgenotype = 3.24e−009). Furthermore, mean plasma ATG5 levels were lower in CP patients than in controls, and individuals carrying the AA genotype of rs6568431 that was positively associated with CP had lower plasma ATG5 levels (P < 0.05). This study demonstrated an association of an ATG5 gene variant and low level of ATG5 protein with CP, and stronger associations with severe clinical manifestations were identified. Our results provide novel evidence for a role of ATG5 in CP and shed light on the molecular mechanisms underlying this neurodevelopmental disorder.
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| 48. |
- Xu, Wenjie, et al.
(författare)
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MathKingdom : Teaching Children Mathematical Language Through Speaking at Home via a Voice-Guided Game
- 2023
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Ingår i: CHI '23. - : Association for Computing Machinery (ACM). - 9781450394215
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Konferensbidrag (refereegranskat)abstract
- The amount and quality of mathematical language in the family are positively associated with promoting children’s mathematical abilities. However, mathematical language in many families is poor. Through need-finding investigation, we developed MathKingdom, a voice-agent-based game that helps children aged 4–7 learn and use rich, accurate mathematical language (e.g., mathematical expressions related to measurement, sequence, patterns). The game has four flows, in which users can wake up, transform, decorate, and perform as their avatars, as well as practice basic mathematical vocabulary, mathematical single sentences, coherent mathematical statements, and free expression. We refined the system design through wizard-of-oz testing and then evaluated it with 18 families. The results showed that MathKingdom effectively engaged children, enhanced their mathematical language skills and mathematical abilities, and encouraged parent-child conversations about math.
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| 49. |
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| 50. |
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