| 1. |
- Shang, Yuchen, et al.
(författare)
-
Ultrahard bulk amorphous carbon from collapsed fullerene
- 2021
-
Ingår i: Nature. - : Nature Publishing Group. - 0028-0836 .- 1476-4687. ; 599:7886, s. 599-604
-
Tidskriftsartikel (refereegranskat)abstract
- Amorphous materials inherit short- and medium-range order from the corresponding crystal and thus preserve some of its properties while still exhibiting novel properties1,2. Due to its important applications in technology, amorphous carbon with sp2 or mixed sp2–sp3 hybridization has been explored and prepared3,4, but synthesis of bulk amorphous carbon with sp3 concentration close to 100% remains a challenge. Such materials inherit the short-/medium-range order of diamond and should also inherit its superior properties5. Here, we successfully synthesized millimetre-sized samples—with volumes 103–104 times as large as produced in earlier studies—of transparent, nearly pure sp3 amorphous carbon by heating fullerenes at pressures close to the cage collapse boundary. The material synthesized consists of many randomly oriented clusters with diamond-like short-/medium-range order and possesses the highest hardness (101.9 ± 2.3 GPa), elastic modulus (1,182 ± 40 GPa) and thermal conductivity (26.0 ± 1.3 W m−1 K−1) observed in any known amorphous material. It also exhibits optical bandgaps tunable from 1.85 eV to 2.79 eV. These discoveries contribute to our knowledge about advanced amorphous materials and the synthesis of bulk amorphous materials by high-pressure and high-temperature techniques and may enable new applications for amorphous solids.
|
|
| 2. |
- Yang, Tao, et al.
(författare)
-
Wind and rainfall erosion energy in large sediment generating and coarse sediment class areas of the middle Yellow river
-
Ingår i: International Soil and Water Conservation Research. - 2095-6339.
-
Tidskriftsartikel (refereegranskat)abstract
- Joint action by strong winds and high-intensive rainfall leads to serious soil erosion problems in large sediment generating and coarse sediment class areas of the middle Yellow River. Investigating the variation of trend and alternating wind and rainfall energy is an important prerequisite for controlling regional sediment transport problems. We calculated the wind and rainfall erosion energies by using the aerodynamic energy and rainfall kinetic energy formulas. The Mann-Kendall (MK) trend test and Theil-Sen approach were used to analyze the spatial-temporal variation and alternation of joint erosion energy during the last 40 years (1979–2018). The results show the following. 1) Wind erosion energy increased and rainfall erosion energy decreased. However, the former is larger than the latter. 2) The dominant erosive energy varies for different seasons. Wind erosive energy dominates in spring, and rainfall erosive energy dominates in summer. 3) There is a regular wind-rainfall-wind alternation of erosive energy. The wind-rainfall energies were alternately distributed in May–July and the rainfall-wind energies were alternately distributed in September–December. Furthermore, the dominant time of rainfall erosive energy decreased when wind erosive energy increased. The results can help decision makers to develop soil erosion control strategies to reduce soil erosion when it occurs in wind and water staggered areas.
|
|
| 3. |
- Zhao, Xin, et al.
(författare)
-
Discovery of Highly Potent Pinanamine-Based Inhibitors against Amantadine- and Oseltamivir-Resistant Influenza A Viruses
- 2018
-
Ingår i: Journal of Medicinal Chemistry. - : American Chemical Society (ACS). - 0022-2623 .- 1520-4804. ; 61:12, s. 5187-5198
-
Tidskriftsartikel (refereegranskat)abstract
- Influenza pandemic is a constant major threat to public health caused by influenza A viruses (IAVs). IAVs are subcategorized by the surface proteins hemagglutinin (HA) and neuraminidase (NA), in which they are both essential targets for drug discovery. While it is of great concern that NA inhibitor oseltamivir resistant strains are frequently identified from human or avian influenza virus, structural and functional characterization of influenza HA has raised hopes for new antiviral therapies. In this study, we explored a structure-activity relationship (SAR) of pinanamine-based antivirals and discovered a potent inhibitor M090 against amantadine-resistant viruses, including the 2009 H1N1 pandemic strains, and oseltamivir-resistant viruses. Mechanism of action studies, particularly hemolysis inhibition, indicated that M090 targets influenza HA and it occupied a highly conserved pocket of the HA(2) domain and inhibited virus-mediated membrane fusion by "locking" the bending state of HA(2) during the conformational rearrangement process. This work provides new binding sites within the HA protein and indicates that this pocket may be a promising target for broad-spectrum anti-influenza A drug design and development.
|
|
| 4. |
- Akhi, Ramin, et al.
(författare)
-
Cross-reactive saliva IgA antibodies to oxidized LDL and periodontal pathogens in humans.
- 2017
-
Ingår i: Journal of Clinical Periodontology. - : Wiley. - 0303-6979 .- 1600-051X. ; 44:7, s. 682-691
-
Tidskriftsartikel (refereegranskat)abstract
- AIM: Oxidized low-density lipoproteins (oxLDL) are formed as a result of lipid peroxidation and are highly immunogenic and proatherogenic. In this study, saliva antibodies binding to oxLDL, Porphyromonas gingivalis (Pg) and Aggregatibacter actinomycetemcomitans (Aa) were characterized and their cross-reactivity was evaluated.MATERIALS AND METHODS: Resting and stimulated saliva samples were collected from 36 healthy adults (mean age 26 years). Saliva IgA, IgG and IgM autoantibody levels to copper oxidized LDL (CuOx-LDL) and malondialdehyde acetaldehyde-modified LDL (MAA-LDL) were determined with chemiluminescence immunoassay.RESULTS: Saliva IgA and IgG antibodies binding to MAA-LDL and CuOx-LDL were detected in all samples and they were associated with the saliva levels of IgA and IgG to P. gingivalis and A. actinomycetemcomitans. Competitive immunoassay showed that saliva antibodies to MAA-LDL cross-reacted specifically with P. gingivalis. The autoantibody levels to oxLDL in saliva were not associated with the autoantibody levels to oxLDL in plasma or with saliva apolipoprotein B 100 levels.CONCLUSIONS: Saliva contains IgA and IgG binding to oxLDL, which showed cross-reactive properties with the periodontal pathogens Porphyromonas gingivalis (P.g). The data suggest that secretory IgA to P.g may participate in immune reactions involved in LDL oxidation through molecular mimicry.
|
|
| 5. |
- Kummu, Outi, et al.
(författare)
-
Carbamyl adducts on low-density lipoprotein induce IgG response in LDLR-/- mice and bind plasma autoantibodies in humans under enhanced carbamylation.
- 2013
-
Ingår i: Antioxidants and Redox Signaling. - : Mary Ann Liebert Inc. - 1523-0864 .- 1557-7716. ; 19:10, s. 1047-62
-
Tidskriftsartikel (refereegranskat)abstract
- AIMS: Post-translational modification of proteins via carbamylation predicts increased risk for coronary artery disease. Uremia and smoke exposure are known to increase carbamylation. The aim was to investigate the role of carbamylated low-density lipoprotein (LDL) immunization on antibody formation and atherogenesis in LDL receptor-deficient (LDLR-/-) mice, and to study autoantibodies to carbamylated proteins in humans with carbamylative load.RESULTS: LDLR-/- mice immunized with carbamylated mouse LDL (msLDL; n=10) without adjuvant showed specific immunoglobulin G (IgG) antibody levels to carbamyl-LDL and malondialdehyde-modified LDL (MDA-LDL) but not to oxidized LDL or native LDL. Immunization did not influence the atherosclerotic plaque area compared with control LDLR-/- mice immunized with native msLDL (n=10) or phosphate-buffered saline (n=11). Humans with high plasma urea levels, as well as smokers, had increased IgG autoantibody levels to carbamyl-modified proteins compared to the subjects with normal plasma urea levels, or to nonsmokers.INNOVATION: Carbamyl-LDL induced specific IgG antibody response cross-reactive with MDA-LDL in mice. IgG antibodies to carbamyl-LDL were also found in human plasma and related to conditions known to have increased carbamylation, such as uremia and smoking. Plasma antibodies to carbamylated proteins may serve as new indicator of in vivo carbamylation.CONCLUSION: These data give insight into mechanisms of in vivo humoral recognition of post-translationally modified structures. Humoral IgG immune response to carbamylated proteins is suggested to play a role in conditions leading to enhanced carbamylation, such as uremia and smoking.
|
|
| 6. |
- Kummu, Outi, et al.
(författare)
-
Human monoclonal Fab and human plasma antibodies to carbamyl-epitopes cross-react with malondialdehyde-adducts.
- 2014
-
Ingår i: Immunology. - : Wiley. - 0019-2805 .- 1365-2567. ; 141:3, s. 416-30
-
Tidskriftsartikel (refereegranskat)abstract
- Oxidized low-density lipoprotein (OxLDL) plays a crucial role in the development of atherosclerosis. Carbamylated LDL has been suggested to promote atherogenesis in patients with chronic kidney disease. Here we observed that plasma IgG and IgM antibodies to carbamylated epitopes were associated with IgG and IgM antibodies to oxidation-specific epitopes (ρ = 0·65-0·86, P < 0·001) in healthy adults, suggesting a cross-reaction between antibodies recognizing carbamyl-epitopes and malondialdehyde (MDA)/malondialdehyde acetaldehyde (MAA) -adducts. We used a phage display technique to clone a human Fab antibody that bound to carbamylated LDL and other carbamylated proteins. Anti-carbamyl-Fab (Fab106) cross-reacted with oxidation-specific epitopes, especially with MDA-LDL and MAA-LDL. We showed that Fab106 bound to apoptotic Jurkat cells known to contain these oxidation-specific epitopes, and the binding was competed with soluble carbamylated and MDA-/MAA-modified LDL and BSA. In addition, Fab106 was able to block the uptake of carbamyl-LDL and MDA-LDL by macrophages and stained mouse atherosclerotic lesions. The observed cross-reaction between carbamylated and MDA-/MAA-modified LDL and its contribution to enhanced atherogenesis in uraemic patients require further investigation.
|
|
| 7. |
- Kyrklund, Mikael, et al.
(författare)
-
Immunization with gingipain A hemagglutinin domain of Porphyromonas gingivalis induces IgM antibodies binding to malondialdehyde-acetaldehyde modified low-density lipoprotein.
- 2018
-
Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 13:1
-
Tidskriftsartikel (refereegranskat)abstract
- Treatment of periodontitis has beneficial effects on systemic inflammation markers that relate to progression of atherosclerosis. We aimed to investigate whether immunization with A hemagglutinin domain (Rgp44) of Porphyromonas gingivalis (Pg), a major etiologic agent of periodontitis, would lead to an antibody response cross-reacting with oxidized low-density lipoprotein (OxLDL) and how it would affect the progression of atherosclerosis in low-density lipoprotein receptor-deficient (LDLR-/-) mice. The data revealed a prominent IgM but not IgG response to malondialdehyde-acetaldehyde modified LDL (MAA-LDL) after Rgp44 and Pg immunizations, implying that Rgp44/Pg and MAA adducts may share cross-reactive epitopes that prompt IgM antibody production and consequently confer atheroprotection. A significant negative association was observed between atherosclerotic lesion and plasma IgA to Rgp44 in Rgp44 immunized mice, supporting further the anti-atherogenic effect of Rgp44 immunization. Plasma IgA levels to Rgp44 and to Pg in both Rgp44- and Pg-immunized mice were significantly higher than those in saline control, suggesting that IgA to Rgp44 could be a surrogate marker of immunization in Pg-immunized mice. Distinct antibody responses in plasma IgA levels to MAA-LDL, to Pg lipopolysaccharides (Pg-LPS), and to phosphocholine (PCho) were observed after Rgp44 and Pg immunizations, indicating that different immunogenic components between Rpg44 and Pg may behave differently in regard of their roles in the development of atherosclerosis. Immunization with Rgp44 also displayed atheroprotective features in modulation of plaque size through association with plasma levels of IL-1α whereas whole Pg bacteria achieved through regulation of anti-inflammatory cytokine levels of IL-5 and IL-10. The present study may contribute to refining therapeutic approaches aiming to modulate immune responses and inflammatory/anti-inflammatory processes in atherosclerosis.
|
|
| 8. |
- Meng, Xiangqi, et al.
(författare)
-
A Novel Intelligent Nonlinear Controller for Dual Active Bridge Converter With Constant Power Loads
- 2023
-
Ingår i: IEEE Transactions on Industrial Electronics. - : Institute of Electrical and Electronics Engineers (IEEE). - 0278-0046 .- 1557-9948. ; 70:3, s. 2887-2896
-
Tidskriftsartikel (refereegranskat)abstract
- The stability of dual active bridge converter (DAB) is threatened when feeding the constant power loads (CPLs). This article proposes a deep reinforcement learning-based backstepping control strategy to solve this problem. First, a nonlinear disturbance observer is adopted to estimate the large-signal nonlinear disturbance. Then, a backstepping controller is used to stabilize the voltage response of the DAB under the large-signal disturbance. Finally, a compensation method based on deep reinforcement learning is developed to intelligently minimize output voltage tracking error and improve the operating efficiency of the system. The proposed controller can guarantee system stability under the large-signal disturbance of the CPL and achieve a fast dynamic response with accurate voltage tracking; it is more adaptive by using the deep reinforcement learning technique through the learning of its neural networks. The effectiveness of the proposed controller is verified by experiments.
|
|
| 9. |
- Shen, Chunguang, et al.
(författare)
-
Uncovering the generic and alloy-specific governing parameters of deformation-induced martensitic transformation in austenitic steel
- 2024
-
Ingår i: Journal of Materials Science. - : Springer Nature. - 0022-2461 .- 1573-4803. ; 59:7, s. 3087-3100
-
Tidskriftsartikel (refereegranskat)abstract
- In this work, a hybrid modeling approach, combining machine learning (ML)and computational thermodynamics, has been applied to predict deformationinduced martensitic transformation (DIMT) and explore the generic and alloyspecifc parameters governing DIMT in austenitic steels. The DIMT model wasestablished based on the ensemble ML algorithms and a comprehensive set ofphysical variables. The developed model is highly generalizable as validated onunseen alloys. The generic governing parameters of DIMT are in good agreementwith previous studies in the literature. However, the evaluated alloy-specifcgoverning parameters reveal large diferences between grades, e.g., 204 series ofaustenitic stainless steels has a quite balanced correlation between strain, stress,temperature, and DIMT, while the 301 series has much stronger correlationbetween stress and DIMT. The fndings in the current study emphasize theimportance that a general DIMT model for steels should include both stress andstrain, as well as other governing parameters, since DIMT can be both stressassisted and strain-induced transformation, and often the effect of appliedmechanical driving force and the formation of new nucleation sites interact.
|
|
| 10. |
- Sheng, Renwang, et al.
(författare)
-
Material stiffness in cooperation with macrophage paracrine signals determines the tenogenic differentiation of mesenchymal stem cells
- 2023
-
Ingår i: Advanced Science. - : John Wiley & Sons. - 2198-3844. ; 10:17
-
Tidskriftsartikel (refereegranskat)abstract
- Stiffness is an important physical property of biomaterials that determines stem cell fate. Guiding stem cell differentiation via stiffness modulation has been considered in tissue engineering. However, the mechanism by which material stiffness regulates stem cell differentiation into the tendon lineage remains controversial. Increasing evidence demonstrates that immune cells interact with implanted biomaterials and regulate stem cell behaviors via paracrine signaling; however, the role of this mechanism in tendon differentiation is not clear. In this study, polydimethylsiloxane (PDMS) substrates with different stiffnesses are developed, and the tenogenic differentiation of mesenchymal stem cells (MSCs) exposed to different stiffnesses and macrophage paracrine signals is investigated. The results reveal that lower stiffnesses facilitates tenogenic differentiation of MSCs, while macrophage paracrine signals at these stiffnesses suppress the differentiation. When exposed to these two stimuli, MSCs still exhibit enhanced tendon differentiation, which is further elucidated by global proteomic analysis. Following subcutaneous implantation in rats for 2 weeks, soft biomaterial induces only low inflammation and promotes tendon-like tissue formation. In conclusion, the study demonstrates that soft, rather than stiff, material has a greater potential to guide tenogenic differentiation of stem cells, which provides comprehensive evidence for optimized bioactive scaffold design in tendon tissue engineering.
|
|
