| 1. |
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| 2. |
- 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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| 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. |
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- 2019
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Tidskriftsartikel (refereegranskat)
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| 5. |
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| 6. |
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| 7. |
- Liu, Lihui, et al.
(författare)
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Two-In-One Method for Graphene Transfer: Simplified Fabrication Process for Organic Light-Emitting Diodes
- 2018
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Ingår i: ACS Applied Materials & Interfaces. - : American Chemical Society (ACS). - 1944-8252 .- 1944-8244. ; 10:8, s. 7289-7295
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Tidskriftsartikel (refereegranskat)abstract
- Graphene as one of the most promising transparent electrode materials has been successfully applied in organic light-emitting diodes (OLEDs). However, traditional poly(methyl methacrylate) (PMMA) transfer method usually results in hardly removed polymeric residues on the graphene surface, which induces unwanted leakage current, poor diode behavior, and even device failure. In this work, we proposed a facile and efficient two-in-one method to obtain clean graphene and fabricate OLEDs, in which the poly(9,9-di-n-octylfluorene-alt-(1,4-phenylene-(4-sec-butylphenyl)imino)-1,4-phenylene) (TFB) layer was inserted between the graphene and PMMA film both as a protector during the graphene transfer and a hole-injection layer in OLEDs. Finally, green OLED devices were successfully fabricated on the PMMA-free graphene/TFB film, and the device luminous efficiency was increased from 64.8 to 74.5 cd/A by using the two-in-one method. Therefore, the proposed two-in-one graphene transfer method realizes a high-efficient graphene transfer and device fabrication process, which is also compatible with the roll-to-roll manufacturing. It is expected that this work can enlighten the design and fabrication of the graphene-based optoelectronic devices.
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| 8. |
- Aad, G., et al.
(författare)
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- 2010
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swepub:Mat__t
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| 9. |
- Aad, G., et al.
(författare)
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- 2011
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swepub:Mat__t
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| 10. |
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| 11. |
- Aad, G., et al.
(författare)
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- 2010
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swepub:Mat__t
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| 12. |
- Aad, G., et al.
(författare)
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- 2010
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swepub:Mat__t
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| 13. |
- Aad, G., et al.
(författare)
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- 2010
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swepub:Mat__t
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| 14. |
- Bai, Ru, et al.
(författare)
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The NF-κB-modulated miR-19a-3p enhances malignancy of human ovarian cancer cells through inhibition of IGFBP-3 expression
- 2019
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Ingår i: Molecular Carcinogenesis. - : Wiley. - 0899-1987 .- 1098-2744. ; 58:12, s. 2254-2265
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Tidskriftsartikel (refereegranskat)abstract
- Ovarian cancer is the most lethal gynecologic malignancy due to the lack of symptoms until advanced stages, and new diagnosis and treatment strategy is in urgent need. In this study, we found higher expression of miR-19a-3p in ovarian cancer tissues compared with that in the adjacent normal tissues. By chromatin immunoprecipitation (ChIP) and electrophoretic mobility shift assay (EMSA) analysis, we showed that nuclear factor-kappaB (NF-κB) binds to the promoter of miR-19a-3p, leading to reduced expression in ovarian cancer cells. Further study indicated that miR-19a-3p inhibits the expression of insulin-like growth factor binding protein-3 (IGFBP-3), resulting in enhanced growth and migration of ovarian cancer cells in vitro and tumor growth in vivo. These results showed that miR-19a-3p enhances the oncogenesis of ovarian cancer through inhibition of IGFBP-3 expression, and which can be inhibited by NF-κB, suggesting an NF-κB/miR-19a-3p/IGFBP-3 pathway in the oncogenesis of ovarian cancer, which expands our understanding of ovarian cancer and they may contribute to the development of new diagnosis and treatment of ovarian cancer.
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| 15. |
- Chang, Kuang Yu, et al.
(författare)
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Observational constraints reduce model spread but not uncertainty in global wetland methane emission estimates
- 2023
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Ingår i: Global Change Biology. - 1354-1013. ; 29:15, s. 4298-4312
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Tidskriftsartikel (refereegranskat)abstract
- The recent rise in atmospheric methane (CH4) concentrations accelerates climate change and offsets mitigation efforts. Although wetlands are the largest natural CH4 source, estimates of global wetland CH4 emissions vary widely among approaches taken by bottom-up (BU) process-based biogeochemical models and top-down (TD) atmospheric inversion methods. Here, we integrate in situ measurements, multi-model ensembles, and a machine learning upscaling product into the International Land Model Benchmarking system to examine the relationship between wetland CH4 emission estimates and model performance. We find that using better-performing models identified by observational constraints reduces the spread of wetland CH4 emission estimates by 62% and 39% for BU- and TD-based approaches, respectively. However, global BU and TD CH4 emission estimate discrepancies increased by about 15% (from 31 to 36 TgCH4 year−1) when the top 20% models were used, although we consider this result moderately uncertain given the unevenly distributed global observations. Our analyses demonstrate that model performance ranking is subject to benchmark selection due to large inter-site variability, highlighting the importance of expanding coverage of benchmark sites to diverse environmental conditions. We encourage future development of wetland CH4 models to move beyond static benchmarking and focus on evaluating site-specific and ecosystem-specific variabilities inferred from observations.
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| 16. |
- Chen, Zheng wei, et al.
(författare)
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Reducing the aerodynamic drag of high-speed trains by air blowing from the nose part: Effect of blowing speed
- 2023
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Ingår i: Journal of Wind Engineering and Industrial Aerodynamics. - 0167-6105. ; 238
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Tidskriftsartikel (refereegranskat)abstract
- To reduce the aerodynamic drag of high-speed trains, this work proposes an air blowing configuration on the head and tail cars of high-speed trains. The variation in the aerodynamic drag and slipstream velocity is analyzed under different blowing velocities, and the flow mechanism for train aerodynamic performance alteration is explained. The results show that under the blowing speeds of Ub = 0.05Ut, 0.10Ut, 0.15Ut, and 0.20Ut, where Ut is the train speed, the total drag coefficient (Cd) decreases by 5.81%, 10.78%, 13.70%, and 15.43% compared to the without-blowing case, respectively. However, with the increase in the blowing speed, the reduction trend of Cd tends to be smoother; namely, the decrement ratio compared to the previous blowing speed for the head car is 9.08%, 0.11%, 0.60%, and 1.14% for Ub = 0.05Ut, 0.10Ut, 0.15Ut, and 0.20Ut, respectively. The blowing measure generates an air gap between the coming flow and train surface, consequently causing a reduction in the viscous and pressure drag. In addition, the structure size and strength of the wake flow under different blowing cases show a decreasing trend from Ub = 0.00Ut to 0.10Ut and then an increasing trend from Ub = 0.10Ut to 0.20Ut. Thus, considering the blowing cost, efficiency, and flow structure evolution comprehensively, the case of Ub = 0.10Ut is recommended. Under this blowing speed, the reduction ratio of the aerodynamic drag is 9.18%, 12.77%, 10.90%, and 10.78% for the head, middle, tail car, and total train, respectively.
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| 17. |
- Chu, Audrey Y, et al.
(författare)
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Multiethnic genome-wide meta-analysis of ectopic fat depots identifies loci associated with adipocyte development and differentiation
- 2017
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 49:1, s. 125-130
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Tidskriftsartikel (refereegranskat)abstract
- Variation in body fat distribution contributes to the metabolic sequelae of obesity. The genetic determinants of body fat distribution are poorly understood. The goal of this study was to gain new insights into the underlying genetics of body fat distribution by conducting sample-size-weighted fixed-effects genome-wide association meta-analyses in up to 9,594 women and 8,738 men of European, African, Hispanic and Chinese ancestry, with and without sex stratification, for six traits associated with ectopic fat (hereinafter referred to as ectopic-fat traits). In total, we identified seven new loci associated with ectopic-fat traits (ATXN1, UBE2E2, EBF1, RREB1, GSDMB, GRAMD3 and ENSA; P < 5 × 10(-8); false discovery rate < 1%). Functional analysis of these genes showed that loss of function of either Atxn1 or Ube2e2 in primary mouse adipose progenitor cells impaired adipocyte differentiation, suggesting physiological roles for ATXN1 and UBE2E2 in adipogenesis. Future studies are necessary to further explore the mechanisms by which these genes affect adipocyte biology and how their perturbations contribute to systemic metabolic disease.
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| 18. |
- de Vries, Paul S., et al.
(författare)
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Multiancestry Genome-Wide Association Study of Lipid Levels Incorporating Gene-Alcohol Interactions
- 2019
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Ingår i: American Journal of Epidemiology. - : Oxford University Press. - 0002-9262 .- 1476-6256. ; 188:6, s. 1033-1054
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Tidskriftsartikel (refereegranskat)abstract
- A person's lipid profile is influenced by genetic variants and alcohol consumption, but the contribution of interactions between these exposures has not been studied. We therefore incorporated gene-alcohol interactions into a multiancestry genome-wide association study of levels of high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and triglycerides. We included 45 studies in stage 1 (genome-wide discovery) and 66 studies in stage 2 (focused follow-up), for a total of 394,584 individuals from 5 ancestry groups. Analyses covered the period July 2014-November 2017. Genetic main effects and interaction effects were jointly assessed by means of a 2-degrees-of-freedom (df) test, and a 1-df test was used to assess the interaction effects alone. Variants at 495 loci were at least suggestively associated (P < 1 x 10(-6)) with lipid levels in stage 1 and were evaluated in stage 2, followed by combined analyses of stage 1 and stage 2. In the combined analysis of stages 1 and 2, a total of 147 independent loci were associated with lipid levels at P < 5 x 10(-8) using 2-df tests, of which 18 were novel. No genome-wide-significant associations were found testing the interaction effect alone. The novel loci included several genes (proprotein convertase subtilisin/kexin type 5 (PCSK5), vascular endothelial growth factor B (VEGFB), and apolipoprotein B mRNA editing enzyme, catalytic polypeptide 1 (APOBEC1) complementation factor (A1CF)) that have a putative role in lipid metabolism on the basis of existing evidence from cellular and experimental models.
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| 19. |
- Deng, Tingzhi, et al.
(författare)
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Hippocampal Transcriptome-Wide Association Study Reveals Correlations Between Impaired Glutamatergic Synapse Pathway and Age-Related Hearing Loss in BXD-Recombinant Inbred Mice
- 2021
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Ingår i: Frontiers in Neuroscience. - : Frontiers Media S.A.. - 1662-4548 .- 1662-453X. ; 15
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Tidskriftsartikel (refereegranskat)abstract
- Age-related hearing loss (ARHL) is associated with cognitive dysfunction; however, the detailed underlying mechanisms remain unclear. The aim of this study is to investigate the potential underlying mechanism with a system genetics approach. A transcriptome-wide association study was performed on aged (12-32 months old) BXD mice strains. The hippocampus gene expression was obtained from 56 BXD strains, and the hearing acuity was assessed from 54 BXD strains. Further correlation analysis identified a total of 1,435 hearing-related genes in the hippocampus (p < 0.05). Pathway analysis of these genes indicated that the impaired glutamatergic synapse pathway is involved in ARHL (p = 0.0038). Further gene co-expression analysis showed that the expression level of glutamine synthetase (Gls), which is significantly correlated with ARHL (n = 26, r = -0.46, p = 0.0193), is a crucial regulator in glutamatergic synapse pathway and associated with learning and memory behavior. In this study, we present the first systematic evaluation of hippocampus gene expression pattern associated with ARHL, learning, and memory behavior. Our results provide novel potential molecular mechanisms involved in ARHL and cognitive dysfunction association.
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| 20. |
- Du, Mingrun, et al.
(författare)
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New ordered structure of amorphous carbon clusters induced by fullerene-cubane reactions
- 2018
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Ingår i: Advanced Materials. - : Wiley-VCH Verlagsgesellschaft. - 0935-9648 .- 1521-4095. ; 30
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Tidskriftsartikel (refereegranskat)abstract
- As a new category of solids, crystalline materials constructed with amorphous building blocks expand the structure categorization of solids, for which designing such new structures and understanding the corresponding formation mechanisms are fundamentally important. Unlike previous reports, new amorphous carbon clusters constructed ordered carbon phases are found here by compressing C8H8/C60 cocrystals, in which the highly energetic cubane (C8H8) exhibits unusual roles as to the structure formation and transformations under pressure. The significant role of C8H8 is to stabilize the boundary interactions of the highly compressed or collapsed C60 clusters which preserves their long‐range ordered arrangement up to 45 GPa. With increasing time at high pressure, the gradual random bonding between C8H8 and carbon clusters, due to “energy release” of highly compressed cubane, leads to the loss of the ability of C8H8 to stabilize the carbon cluster arrangement. Thus a transition from short‐range disorder to long‐range disorder (amorphization) occurs in the formed material. The spontaneous bonding reconstruction most likely results in a 3D network in the material, which can create ring cracks on diamond anvils.
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| 21. |
- Feitosa, Mary F., et al.
(författare)
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Novel genetic associations for blood pressure identified via gene-alcohol interaction in up to 570K individuals across multiple ancestries
- 2018
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Ingår i: PLOS ONE. - : Public library science. - 1932-6203. ; 13:6
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Tidskriftsartikel (refereegranskat)abstract
- Heavy alcohol consumption is an established risk factor for hypertension; the mechanism by which alcohol consumption impact blood pressure (BP) regulation remains unknown. We hypothesized that a genome-wide association study accounting for gene-alcohol consumption interaction for BP might identify additional BP loci and contribute to the understanding of alcohol-related BP regulation. We conducted a large two-stage investigation incorporating joint testing of main genetic effects and single nucleotide variant (SNV)-alcohol consumption interactions. In Stage 1, genome-wide discovery meta-analyses in approximate to 131 K individuals across several ancestry groups yielded 3,514 SNVs (245 loci) with suggestive evidence of association (P <1.0 x 10(-5)). In Stage 2, these SNVs were tested for independent external replication in individuals across multiple ancestries. We identified and replicated (at Bonferroni correction threshold) five novel BP loci (380 SNVs in 21 genes) and 49 previously reported BP loci (2,159 SNVs in 109 genes) in European ancestry, and in multi-ancestry meta-analyses (P < 5.0 x 10(-8)). For African ancestry samples, we detected 18 potentially novel BP loci (P< 5.0 x 10(-8)) in Stage 1 that warrant further replication. Additionally, correlated meta-analysis identified eight novel BP loci (11 genes). Several genes in these loci (e.g., PINX1, GATA4, BLK, FTO and GABBR2 have been previously reported to be associated with alcohol consumption. These findings provide insights into the role of alcohol consumption in the genetic architecture of hypertension.
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| 22. |
- Feng, Ruizhi, et al.
(författare)
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MiRNA-320 in the human follicular fluid is associated with embryo quality in vivo and affects mouse embryonic development in vitro.
- 2015
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Ingår i: Scientific reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- Previous work from our laboratory demonstrated the existence of miRNAs in human follicular fluid. In the current study, we have sought to identify miRNAs that might affect oocyte/embryo quality in patients undergoing intracytoplasmic sperm injection and to investigate their roles in in vitro fertilization outcomes in mouse oocytes. 53 samples were classified as Group 1 (high quality) if the day-3 embryos had seven and more cells or as Group 2 (low quality) if the embryos had six and fewer cells. TaqMan Human microRNAs cards and qRT-PCR were performed to verify differently expressed miRNAs. The function of the corresponding miRNA was investigated in mouse oocytes by injecting them with miRNA-inhibitor oligonucleotides. We found that hsa-miR-320a and hsa-miR-197 had significantly higher expression levels in the Group 1 follicular fluids than in Group 2 (p = 0.0073 and p = 0.008, respectively). Knockdown of mmu-miR-320 in mouse oocytes strongly decreased the proportions of MII oocytes that developed into two-cell and blastocyst stage embryos (p = 0.0048 and p = 0.0069, respectively). Wnt signaling pathway components had abnormal expression level in miR-320 inhibitor-injected oocytes. This study provides the first evidence that miRNAs in human follicular fluid are indicative of and can influence embryo quality.
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| 23. |
- Feng, Ruizhi, et al.
(författare)
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Mutations in TUBB8 and Human Oocyte Meiotic Arrest.
- 2016
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Ingår i: The New England journal of medicine. - 1533-4406. ; 374:3, s. 223-232
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Tidskriftsartikel (refereegranskat)abstract
- Background Human reproduction depends on the fusion of a mature oocyte with a sperm cell to form a fertilized egg. The genetic events that lead to the arrest of human oocyte maturation are unknown. Methods We sequenced the exomes of five members of a four-generation family, three of whom had infertility due to oocyte meiosis I arrest. We performed Sanger sequencing of a candidate gene, TUBB8, in DNA samples from these members, additional family members, and members of 23 other affected families. The expression of TUBB8 and all other β-tubulin isotypes was assessed in human oocytes, early embryos, sperm cells, and several somatic tissues by means of a quantitative reverse-transcriptase-polymerase-chain-reaction assay. We evaluated the effect of the TUBB8 mutations on the assembly of the heterodimer consisting of one α-tubulin polypeptide and one β-tubulin polypeptide (α/β-tubulin heterodimer) in vitro, on microtubule architecture in HeLa cells, on microtubule dynamics in yeast cells, and on spindle assembly in mouse and human oocytes. Results We identified seven mutations in the primate-specific gene TUBB8 that were responsible for oocyte meiosis I arrest in 7 of the 24 families. TUBB8 expression is unique to oocytes and the early embryo, in which this gene accounts for almost all the expressed β-tubulin. The mutations affect chaperone-dependent folding and assembly of the α/β-tubulin heterodimer, disrupt microtubule behavior on expression in cultured cells, alter microtubule dynamics in vivo, and cause catastrophic spindle-assembly defects and maturation arrest on expression in mouse and human oocytes. Conclusions TUBB8 mutations have dominant-negative effects that disrupt microtubule behavior and oocyte meiotic spindle assembly and maturation, causing female infertility. (Funded by the National Basic Research Program of China and others.).
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| 24. |
- Henry, Carole, et al.
(författare)
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Monoclonal Antibody Responses after Recombinant Hemagglutinin Vaccine versus Subunit Inactivated Influenza Virus Vaccine : a Comparative Study
- 2019
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Ingår i: Journal of Virology. - : AMER SOC MICROBIOLOGY. - 0022-538X .- 1098-5514. ; 93:21
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Tidskriftsartikel (refereegranskat)abstract
- Vaccination is the best measure of protection against influenza virus infection. Vaccine-induced antibody responses target mainly the hemagglutinin (HA) surface glycoprotein, composed of the head and the stalk domains. Recently two novel vaccine platforms have been developed for seasonal influenza vaccination: a recombinant HA vaccine produced in insect cells (Flublok) and Flucelvax, prepared from virions produced in mammalian cells. In order to compare the fine specificity of the antibodies induced by these two novel vaccine platforms, we characterized 42 Flublok-induced monoclonal antibodies (MAbs) and 38 Flucelvax-induced MAbs for avidity, cross-reactivity, and any selectivity toward the head versus the stalk domain. These studies revealed that Flublok induced a greater proportion of MAbs targeting epitopes near the receptor-binding domain on HA head (hemagglutinin inhibition-positive MAbs) than Flucelvax, while the two vaccines induced similar low frequencies of stalk-reactive MAbs. Finally, mice immunized with Flublok and Flucelvax also induced similar frequencies of stalk-reactive antibody-secreting cells, showing that HA head immunodominance is independent of immune memory bias. Collectively, our results suggest that these vaccine formulations are similarly immunogenic but differ in the preferences of the elicited antibodies toward the receptor-binding domain on the HA head.IMPORTANCE: There are ongoing efforts to increase the efficacy of influenza vaccines and to promote production strategies that can rapidly respond to newly emerging viruses. It is important to understand if current alternative seasonal vaccines, such as Flublok and Flucelvax, that use alternate production strategies can induce protective influenza-specific antibodies and to evaluate what type of epitopes are targeted by distinct vaccine formulations.
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| 25. |
- Huang, Shan, et al.
(författare)
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Dipyridamole enhances the anti-cancer ability of aspirin against colorectal cancer by inducing apoptosis in an unfolded protein response-dependent manner
- 2023
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Ingår i: Cellular Oncology. - : Springer Science and Business Media LLC. - 2211-3428 .- 2211-3436. ; 46:4, s. 953-967
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: Available evidence indicates that dipyridamole enhances the anti-thrombotic effects of aspirin for the prevention of secondary strokes. Aspirin is a well-known non-steroid anti-inflammatory drug. This anti-inflammatory property has turned aspirin into a potential drug for inflammation-related cancers such as colorectal cancer (CRC). Here, we aimed to explore whether the anti-cancer effect of aspirin against CRC could be improved by combined administration with dipyridamole.METHODS: Population-based clinical data analysis was conducted to assess a possible therapeutic effect of combined dipyridamole and aspirin treatment in inhibiting CRC compared with either monotherapy. This therapeutic effect was further verified in different CRC mouse models, i.e. an orthotopic xenograft mouse model, an AOM/DSS mouse model, an Apc min/+ mouse model and a patient derived xenograft (PDX) mouse model. The in vitro effects of the drugs on CRC cells were tested using CCK8 and flow cytometry assays. RNA-Seq, Western blotting, qRT-PCR and flow cytometry were used to identify the underlying molecular mechanisms. RESULTS: We found that dipyridamole combined with aspirin had a better inhibitory effect on CRC than either monotherapy alone. The enhanced anti-cancer effect of the combined use of dipyridamole with aspirin was found to rely on the induction of an overwhelmed endoplasmic reticulum (ER) stress and subsequent pro-apoptotic unfolded protein response (UPR), which was different from the anti-platelet effect.CONCLUSIONS: Our data indicate that the anti-cancer effect of aspirin against CRC may be enhanced by combined administration with dipyridamole. In case further clinical studies confirm our findings, these may be repurposed as adjuvant agents.
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| 26. |
- Jin, Ying-Hui, et al.
(författare)
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Chemoprophylaxis, diagnosis, treatments, and discharge management of COVID-19 : An evidence-based clinical practice guideline (updated version)
- 2020
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Ingår i: Military Medical Research. - : Springer Science and Business Media LLC. - 2054-9369. ; 7:1
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Tidskriftsartikel (refereegranskat)abstract
- The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the cause of a rapidly spreading illness, coronavirus disease 2019 (COVID-19), affecting more than seventeen million people around the world. Diagnosis and treatment guidelines for clinicians caring for patients are needed. In the early stage, we have issued "A rapid advice guideline for the diagnosis and treatment of 2019 novel coronavirus (2019-nCoV) infected pneumonia (standard version)"; now there are many direct evidences emerged and may change some of previous recommendations and it is ripe for develop an evidence-based guideline. We formed a working group of clinical experts and methodologists. The steering group members proposed 29 questions that are relevant to the management of COVID-19 covering the following areas: chemoprophylaxis, diagnosis, treatments, and discharge management. We searched the literature for direct evidence on the management of COVID-19, and assessed its certainty generated recommendations using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach. Recommendations were either strong or weak, or in the form of ungraded consensus-based statement. Finally, we issued 34 statements. Among them, 6 were strong recommendations for, 14 were weak recommendations for, 3 were weak recommendations against and 11 were ungraded consensus-based statement. They covered topics of chemoprophylaxis (including agents and Traditional Chinese Medicine (TCM) agents), diagnosis (including clinical manifestations, reverse transcription-polymerase chain reaction (RT-PCR), respiratory tract specimens, IgM and IgG antibody tests, chest computed tomography, chest x-ray, and CT features of asymptomatic infections), treatments (including lopinavir-ritonavir, umifenovir, favipiravir, interferon, remdesivir, combination of antiviral drugs, hydroxychloroquine/chloroquine, interleukin-6 inhibitors, interleukin-1 inhibitors, glucocorticoid, qingfei paidu decoction, lianhua qingwen granules/capsules, convalescent plasma, lung transplantation, invasive or noninvasive ventilation, and extracorporeal membrane oxygenation (ECMO)), and discharge management (including discharge criteria and management plan in patients whose RT-PCR retesting shows SARS-CoV-2 positive after discharge). We also created two figures of these recommendations for the implementation purpose. We hope these recommendations can help support healthcare workers caring for COVID-19 patients.
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| 27. |
- Liu, Jiale, et al.
(författare)
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STING inhibitors sensitize platinum chemotherapy in ovarian cancer by inhibiting the CGAS-STING pathway in cancer-associated fibroblasts (CAFs)
- 2024
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Ingår i: Cancer Letters. - : Elsevier. - 0304-3835 .- 1872-7980. ; 588
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Tidskriftsartikel (refereegranskat)abstract
- Chemotherapy resistance in ovarian cancer hampers cure rates, with cancer-associated fibroblasts (CAFs) playing a pivotal role. Despite their known impact on cancer progression and chemotherapy resistance, the specific mechanism by which CAFs regulate the tumor inflammatory environment remains unclear. This study reveals that cisplatin facilitates DNA transfer from ovarian cancer cells to CAFs, activating the CGAS-STING-IFNB1 pathway in CAFs and promoting IFNB1 release. Consequently, this reinforces cancer cell resistance to platinum drugs. High STING expression in the tumor stroma was associated with a poor prognosis, while inhibiting STING expression enhanced ovarian cancer sensitivity. Understanding the relevance of the CGAS-STING pathway in CAFs for platinum resistance suggests targeting STING as a promising combination therapy for ovarian cancer, providing potential avenues for improved treatment outcomes.
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| 28. |
- Ma, Li-Jun, et al.
(författare)
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Genomic analysis of the basal lineage fungus Rhizopus oryzae reveals a whole-genome duplication.
- 2009
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Ingår i: PLoS genetics. - : Public Library of Science (PLoS). - 1553-7404. ; 5:7, s. e1000549-
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Tidskriftsartikel (refereegranskat)abstract
- Rhizopus oryzae is the primary cause of mucormycosis, an emerging, life-threatening infection characterized by rapid angioinvasive growth with an overall mortality rate that exceeds 50%. As a representative of the paraphyletic basal group of the fungal kingdom called "zygomycetes," R. oryzae is also used as a model to study fungal evolution. Here we report the genome sequence of R. oryzae strain 99-880, isolated from a fatal case of mucormycosis. The highly repetitive 45.3 Mb genome assembly contains abundant transposable elements (TEs), comprising approximately 20% of the genome. We predicted 13,895 protein-coding genes not overlapping TEs, many of which are paralogous gene pairs. The order and genomic arrangement of the duplicated gene pairs and their common phylogenetic origin provide evidence for an ancestral whole-genome duplication (WGD) event. The WGD resulted in the duplication of nearly all subunits of the protein complexes associated with respiratory electron transport chains, the V-ATPase, and the ubiquitin-proteasome systems. The WGD, together with recent gene duplications, resulted in the expansion of multiple gene families related to cell growth and signal transduction, as well as secreted aspartic protease and subtilase protein families, which are known fungal virulence factors. The duplication of the ergosterol biosynthetic pathway, especially the major azole target, lanosterol 14alpha-demethylase (ERG11), could contribute to the variable responses of R. oryzae to different azole drugs, including voriconazole and posaconazole. Expanded families of cell-wall synthesis enzymes, essential for fungal cell integrity but absent in mammalian hosts, reveal potential targets for novel and R. oryzae-specific diagnostic and therapeutic treatments.
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| 29. |
- Mahajan, Anubha, et al.
(författare)
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Multi-ancestry genetic study of type 2 diabetes highlights the power of diverse populations for discovery and translation
- 2022
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Ingår i: Nature Genetics. - : Springer Nature. - 1061-4036 .- 1546-1718. ; 54:5, s. 560-572
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Tidskriftsartikel (refereegranskat)abstract
- We assembled an ancestrally diverse collection of genome-wide association studies (GWAS) of type 2 diabetes (T2D) in 180,834 affected individuals and 1,159,055 controls (48.9% non-European descent) through the Diabetes Meta-Analysis of Trans-Ethnic association studies (DIAMANTE) Consortium. Multi-ancestry GWAS meta-analysis identified 237 loci attaining stringent genome-wide significance (P < 5 x 10(-9)), which were delineated to 338 distinct association signals. Fine-mapping of these signals was enhanced by the increased sample size and expanded population diversity of the multi-ancestry meta-analysis, which localized 54.4% of T2D associations to a single variant with >50% posterior probability. This improved fine-mapping enabled systematic assessment of candidate causal genes and molecular mechanisms through which T2D associations are mediated, laying the foundations for functional investigations. Multi-ancestry genetic risk scores enhanced transferability of T2D prediction across diverse populations. Our study provides a step toward more effective clinical translation of T2D GWAS to improve global health for all, irrespective of genetic background. Genome-wide association and fine-mapping analyses in ancestrally diverse populations implicate candidate causal genes and mechanisms underlying type 2 diabetes. Trans-ancestry genetic risk scores enhance transferability across populations.
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| 30. |
- Pan, Yuxian, et al.
(författare)
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How well do multi-fire danger rating indices represent China forest fire variations across multi-time scales?
- 2024
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Ingår i: ENVIRONMENTAL RESEARCH LETTERS. - 1748-9326. ; 19:4
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Tidskriftsartikel (refereegranskat)abstract
- To better support wildfire predictions and risk assessment, multiple fire danger rating indices (FDRIs) have been developed but their credibility in China remains obscure. Compared with the satellite fire observations, 13 FDRIs are evaluated for the historical (2003-2021) forest fire frequency in China from four different time scales: active seasons, trends, interannual variations (IAVs) and discrimination of fire/non-fire days (DFDs). Most FDRIs effectively capture the double active seasons over Southwest China and the dominant active season over Northeast and South China but fail over the other regions. FDRIs with cloud cover perform better in capturing climatological fire seasonality. All FDRIs fail to reproduce the significant decreasing trend of forest fires speculatively due to local fire management and discordant changes in meteorological elements. Most FDRIs have the advantages of the IAVs and DFDs over Southwest China but exhibit deficiencies over the other regions. FDRIs incorporating wind speed perform best in representing both IAVs and DFDs, indicating the indispensable effect of surface wind on the interannual/daily variation of fire danger. This study provides a credible reference for utilizing FDRIs in China, as well as offers insights for developing better regional FDRIs to represent different time-scale variations.
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| 31. |
- Razavi-Shearer, Devin M., et al.
(författare)
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Adjusted estimate of the prevalence of hepatitis delta virus in 25 countries and territories
- 2024
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Ingår i: JOURNAL OF HEPATOLOGY. - 0168-8278 .- 1600-0641. ; 80:2, s. 232-242
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Tidskriftsartikel (refereegranskat)abstract
- Background & Aims: Hepatitis delta virus (HDV) is a satellite RNA virus that requires the hepatitis B virus (HBV) for assembly and propagation. Individuals infected with HDV progress to advanced liver disease faster than HBV-monoinfected individuals. Recent studies have estimated the global prevalence of anti-HDV antibodies among the HBV-infected population to be 5-15%. This study aimed to better understand HDV prevalence at the population level in 25 countries/territories. Methods: We conducted a literature review to determine the prevalence of anti-HDV and HDV RNA in hepatitis B surface antigen (HBsAg)-positive individuals in 25 countries/territories. Virtual meetings were held with experts from each setting to discuss the findings and collect unpublished data. Data were weighted for patient segments and regional heterogeneity to estimate the prevalence in the HBV-infected population. The findings were then combined with The Polaris Observatory HBV data to estimate the anti-HDV and HDV RNA prevalence in each country/territory at the population level. Results: After adjusting for geographical distribution, disease stage and special populations, the anti-HDV prevalence among the HBsAg+ population changed from the literature estimate in 19 countries. The highest anti-HDV prevalence was 60.1% in Mongolia. Once adjusted for the size of the HBsAg+ population and HDV RNA positivity rate, China had the highest absolute number of HDV RNA+ cases. Conclusions: We found substantially lower HDV prevalence than previously reported, as prior meta-analyses primarily focused on studies conducted in groups/regions that have a higher probability of HBV infection: tertiary care centers, specific risk groups or geographical regions. There is large uncertainty in HDV prevalence estimates. The implementation of reflex testing would improve estimates, while also allowing earlier linkage to care for HDV RNA+ individuals. The logistical and economic burden of reflex testing on the health system would be limited, as only HBsAg+ cases would be screened.
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| 32. |
- Sampson, Joshua N., et al.
(författare)
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Analysis of Heritability and Shared Heritability Based on Genome-Wide Association Studies for 13 Cancer Types
- 2015
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Ingår i: Journal of the National Cancer Institute. - : Oxford University Press (OUP). - 0027-8874 .- 1460-2105. ; 107:12
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Tidskriftsartikel (refereegranskat)abstract
- Background: Studies of related individuals have consistently demonstrated notable familial aggregation of cancer. We aim to estimate the heritability and genetic correlation attributable to the additive effects of common single-nucleotide polymorphisms (SNPs) for cancer at 13 anatomical sites. Methods: Between 2007 and 2014, the US National Cancer Institute has generated data from genome-wide association studies (GWAS) for 49 492 cancer case patients and 34 131 control patients. We apply novel mixed model methodology (GCTA) to this GWAS data to estimate the heritability of individual cancers, as well as the proportion of heritability attributable to cigarette smoking in smoking-related cancers, and the genetic correlation between pairs of cancers. Results: GWAS heritability was statistically significant at nearly all sites, with the estimates of array-based heritability, h(l)(2), on the liability threshold (LT) scale ranging from 0.05 to 0.38. Estimating the combined heritability of multiple smoking characteristics, we calculate that at least 24% (95% confidence interval [CI] = 14% to 37%) and 7% (95% CI = 4% to 11%) of the heritability for lung and bladder cancer, respectively, can be attributed to genetic determinants of smoking. Most pairs of cancers studied did not show evidence of strong genetic correlation. We found only four pairs of cancers with marginally statistically significant correlations, specifically kidney and testes (rho = 0.73, SE = 0.28), diffuse large B-cell lymphoma (DLBCL) and pediatric osteosarcoma (rho = 0.53, SE = 0.21), DLBCL and chronic lymphocytic leukemia (CLL) (rho = 0.51, SE = 0.18), and bladder and lung (rho = 0.35, SE = 0.14). Correlation analysis also indicates that the genetic architecture of lung cancer differs between a smoking population of European ancestry and a nonsmoking Asian population, allowing for the possibility that the genetic etiology for the same disease can vary by population and environmental exposures. Conclusion: Our results provide important insights into the genetic architecture of cancers and suggest new avenues for investigation.
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| 33. |
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| 34. |
- Sung, Yun Ju, et al.
(författare)
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A multi-ancestry genome-wide study incorporating gene-smoking interactions identifies multiple new loci for pulse pressure and mean arterial pressure
- 2019
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Ingår i: Human Molecular Genetics. - : Oxford University Press. - 0964-6906 .- 1460-2083. ; 28:15, s. 2615-2633
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Tidskriftsartikel (refereegranskat)abstract
- Elevated blood pressure (BP), a leading cause of global morbidity and mortality, is influenced by both genetic and lifestyle factors. Cigarette smoking is one such lifestyle factor. Across five ancestries, we performed a genome-wide gene–smoking interaction study of mean arterial pressure (MAP) and pulse pressure (PP) in 129 913 individuals in stage 1 and follow-up analysis in 480 178 additional individuals in stage 2. We report here 136 loci significantly associated with MAP and/or PP. Of these, 61 were previously published through main-effect analysis of BP traits, 37 were recently reported by us for systolic BP and/or diastolic BP through gene–smoking interaction analysis and 38 were newly identified (P < 5 × 10−8, false discovery rate < 0.05). We also identified nine new signals near known loci. Of the 136 loci, 8 showed significant interaction with smoking status. They include CSMD1 previously reported for insulin resistance and BP in the spontaneously hypertensive rats. Many of the 38 new loci show biologic plausibility for a role in BP regulation. SLC26A7 encodes a chloride/bicarbonate exchanger expressed in the renal outer medullary collecting duct. AVPR1A is widely expressed, including in vascular smooth muscle cells, kidney, myocardium and brain. FHAD1 is a long non-coding RNA overexpressed in heart failure. TMEM51 was associated with contractile function in cardiomyocytes. CASP9 plays a central role in cardiomyocyte apoptosis. Identified only in African ancestry were 30 novel loci. Our findings highlight the value of multi-ancestry investigations, particularly in studies of interaction with lifestyle factors, where genomic and lifestyle differences may contribute to novel findings.
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| 35. |
- Wang, Zhaoming, et al.
(författare)
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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
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Ingår i: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 23:24, s. 6616-6633
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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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| 36. |
- Xiang, W. -J, et al.
(författare)
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Camera calibration by hybrid hopfield network and self-adaptive genetic algorithm
- 2012
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Ingår i: Measurement Science Review. - : Walter de Gruyter GmbH. - 1335-8871. ; 12:6, s. 302-308
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Tidskriftsartikel (refereegranskat)abstract
- A new approach based on hybrid Hopfield neural network and self-adaptive genetic algorithm for camera calibration is proposed. First, a Hopfield network based on dynamics is structured according to the normal equation obtained from experiment data. The network has 11 neurons, its weights are elements of the symmetrical matrix of the normal equation and keep invariable, whose input vector is corresponding to the right term of normal equation, and its output signals are corresponding to the fitting coefficients of the camera's projection matrix. At the same time an innovative genetic algorithm is presented to get the global optimization solution, where the cross-over probability and mutation probability are tuned self-adaptively according to the evolution speed factor in longitudinal direction and the aggregation degree factor in lateral direction, respectively. When the system comes to global equilibrium state, the camera's projection matrix is estimated from the output vector of the Hopfield network, so the camera calibration is completed. Finally, the precision analysis is carried out, which demonstrates that, as opposed to the existing methods, such as Faugeras's, the proposed approach has high precision, and provides a new scheme for machine vision system and precision manufacture.
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| 37. |
- Yao, Xingang, et al.
(författare)
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Inhibition of dengue viral infection by diasarone-I is associated with 2'O methyltransferase of NS5
- 2018
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Ingår i: European Journal of Pharmacology. - Amsterdam : Elsevier. - 0014-2999 .- 1879-0712. ; 821, s. 11-20
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Tidskriftsartikel (refereegranskat)abstract
- Dengue virus (DENV) is the most prevalent mosquito borne viral pathogen worldwide. However, antiviral drugs against this infection are not available. To identify novel anti-DENV compound from traditional Chinese medicine, we discovered the ethanol extract of Acorus tatarinowii Schott containing potent anti-DENV activity and diasarone-I was isolated from this extract. Diasarone-I has antiviral effect with half maximal effective concentration (EC50) of 4.5μM and half maximal cytotoxicity concentration (CC50) of >80μM. Time of drug addition assay suggested that this compound inhibited at RNA replication step in the DENV life cycle. Further, in silico analysis indicated that diasarone-I might act as an inhibitor of 2'O Methyltransferase of NS5. Diasarone-I has also decreased the DENV2-induced STAT1 phosphorylation and ISGs. In summary, we suggest that diasarone-I may be a 2'O Methyltransferase inhibitor and might serve as a potential candidate for the treatment of DENV2 infections. © 2017 Elsevier B.V.
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| 38. |
- Yao, Xingang, et al.
(författare)
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Tatanan A from the Acorus calamus L. root inhibited dengue virus proliferation and infections
- 2018
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Ingår i: Phytomedicine. - München : Elsevier. - 0944-7113 .- 1618-095X. ; 42, s. 258-267
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Acorus calamus l. (Acoraceae) is a well-known traditional Chinese medicinal plant, whose root are historically mainly used to treat neurodegenerative diseases, and for cholera treatment. This datum strongly indicates the antimicrobial activity of A. calamus.PURPOSE: Our goal is to find the active constituents of A. calamus to treat dengue virus (DENV) infections, and to study the effects and mechanisms of these active substances.METHODS: The root of A. calamus was extracted by ethanol. Mosquito larva C6/36 cells were used for DENV2 replication and transfection host. Mouse kidney fibroblast cells (BHK-21) were used as a host cell to study the infection ability of the virus. DENV2-induced cytopathic effect (CPE) and plaque assay were used to evaluate the inhibitory effect of A. calamus extracts on DENV2 infectivity inhibition. The levels of E and NS1 protein expression were measured by real-time PCR and western blot assays.RESULTS: 12 compounds were isolated from ethanol extract of A. calamus root, tatanan A showed the best anti-DENV ability among these 12 compounds, which significantly alleviated DENV2-induced CPE and cytotoxicity effects, with an EC50 of 3.9 µM. In addition, RNA replication assay further confirmed the antivirus ability of tatanan A. Time-addition assay showed that tatanan A affected the early stage of viral RNA replication, which in turn inhibited mRNA and protein levels of DENV2.CONCLUSIONS: These results demonstrated the anti-DENV2 effect of tatanan A, in inhibiting DENV2 RNA replication and infections. In summary, tatanan A was found to be a novel natural DENV inhibitor and a potential candidate for the treatment of DENV infectious disease.
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| 39. |
- Zhang, Huai, et al.
(författare)
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A global survey on the use of the international classification of diseases codes for metabolic dysfunction-associated fatty liver disease.
- 2024
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Ingår i: Hepatology international. - 1936-0541.
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Tidskriftsartikel (refereegranskat)abstract
- With the implementation of the 11th edition of the International Classification of Diseases (ICD-11) and the publication of the metabolic dysfunction-associated fatty liver disease (MAFLD) nomenclature in 2020, it is important to establish consensus for the coding of MAFLD in ICD-11. This will inform subsequent revisions of ICD-11.Using the Qualtrics XM and WJX platforms, questionnaires were sent online to MAFLD-ICD-11 coding collaborators, authors of papers, and relevant association members.A total of 890 international experts in various fields from 61 countries responded to the survey. We also achieved full coverage of provincial-level administrative regions in China. 77.1% of respondents agreed that MAFLD should be represented in ICD-11 by updating NAFLD, with no significant regional differences (77.3% in Asia and 76.6% in non-Asia, p=0.819). Over 80% of respondents agreed or somewhat agreed with the need to assign specific codes for progressive stages of MAFLD (i.e. steatohepatitis) (92.2%), MAFLD combined with comorbidities (84.1%), or MAFLD subtypes (i.e., lean, overweight/obese, and diabetic) (86.1%).This global survey by a collaborative panel of clinical, coding, health management and policy experts, indicates agreement that MAFLD should be coded in ICD-11. The data serves as a foundation for corresponding adjustments in the ICD-11 revision.
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| 40. |
- Zhang, H., et al.
(författare)
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Ageing hardening and corrosion resistance of Fe 60 Cr 18 Cu 3 (MnCoNiMoAlTi) 19 medium-entropy alloy
- 2023
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Ingår i: Zhongguo Youse Jinshu Xuebao/Chinese Journal of Nonferrous Metals. - 1004-0609. ; 33:8, s. 2622-2634
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Tidskriftsartikel (refereegranskat)abstract
- Fe60Cr18Cu3(CoMnMoNiAlTi)19 medium-entropy stainless alloy (MEA) was prepared by vacuum arc furnace melting. The ageing hardening mechanism and corrosion resistance of alloy were studied. The results show that the MEA has simple BCC solid solution phase after solidification, due to the influence of medium-entropy effect. HRTEM results show that the high level of lattice distortion in the supersaturated BCC solid solution matrix leads to a high amount of nanometer-sized ordered B2 coherent precipitates after ageing treatment, and the maximum hardness of MESS after ageing reaches 621HV0.5. The resistance to corrosion in hot sulfuric acid and to pitting in the NaCl solution are both greatly improved compared with the conventional 17-4PH steel, as evidenced by more stable anodic passivation zone and significantly reduced corrosion dissolution rate in the MEA. XPS analyses results show that the multi-component passive film, which composes of high contents of anti-corrosion elements including Crhy3 +, Crox3 +, Cu+ox, Ti4ox+, Al3ox+ and Mo6ox+, is the main reason for the excellent pitting resistance and the reduced growth of pitting pit in the NaCl solution.
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| 41. |
- Zhou, Yao, et al.
(författare)
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Enabling High-Performance Polypropylene Nanocomposites With Interfacial Deep Traps
- 2023
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Ingår i: IEEE Transactions on Dielectrics and Electrical Insulation. - 1558-4135 .- 1070-9878. ; 30:1, s. 484-487
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Tidskriftsartikel (refereegranskat)abstract
- Polymer nanocomposites are the material of choice for dc insulation. The emerging demand for high-capacity high voltage direct current (HVdc) power transmission requires polymer nanocomposites capable of safe and stable operation at high temperatures. However, the high-temperature electrical properties of current polymer nanocomposites are still unsatisfactory. Here, we report that the modulation of polymer/nanoparticle interfaces can greatly improve the high-temperature insulation properties of polypropylene (PP)-based nanocomposite for recyclable HVdc cable insulation application. The nanoparticles are surface-modified with PP-graft-maleic anhydride (PP- g -mah), which is not only well miscible with PP but also contains polar groups to act as interfacial deep traps. We demonstrate that the interfacial deep traps can improve the dc breakdown strength and the electrical resistivity of polymer nanocomposite by inhibiting the charge injection. This work deepens the understanding of interfacial effects in polymer nanocomposites and provides new opportunities for designing high-performance recyclable insulation materials for HVdc cables.
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| 42. |
- Zhou, Yao, et al.
(författare)
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Insight Into Space Charge Suppression by Interfacial Deep Traps in Polymer Nanocomposites
- 2022
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Ingår i: IEEE Transactions on Dielectrics and Electrical Insulation. - 1558-4135 .- 1070-9878. ; 29:6, s. 2402-2404
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Tidskriftsartikel (refereegranskat)abstract
- Polymer nanocomposites are attractive for HVDC insulation applications, especially for HVDC cables, due to their ability to suppress space charge accumulation through interfacial effects. However, direct evidence to support the existence of interfacial effects at the nanoscale is still lacking. Therefore, rational design and molecular engineering of the interfaces to improve the insulation properties of polymer nanocomposites remain unavailable. Here, we show that efficient space charge suppression can be achieved in polymer nanocomposites at temperatures up to 100 °C by introducing local deep traps through carefully designed nanoparticle/polymer interfaces. The local interfacial deep traps are directly detected at the nanoscale using intermodulation electrostatic force microscopy (ImEFM). This work provides a deep understanding of the interfacial effects in polymer nanocomposites and will enable the rational design of interfaces for high-performance insulation materials.
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