| 1. |
- 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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| 2. |
- de las Fuentes, Lisa, et al.
(författare)
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Gene-educational attainment interactions in a multi-ancestry genome-wide meta-analysis identify novel blood pressure loci
- 2021
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Ingår i: Molecular Psychiatry. - : Springer Nature. - 1359-4184 .- 1476-5578. ; 26:6, s. 2111-2125
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Tidskriftsartikel (refereegranskat)abstract
- Educational attainment is widely used as a surrogate for socioeconomic status (SES). Low SES is a risk factor for hypertension and high blood pressure (BP). To identify novel BP loci, we performed multi-ancestry meta-analyses accounting for gene-educational attainment interactions using two variables, “Some College” (yes/no) and “Graduated College” (yes/no). Interactions were evaluated using both a 1 degree of freedom (DF) interaction term and a 2DF joint test of genetic and interaction effects. Analyses were performed for systolic BP, diastolic BP, mean arterial pressure, and pulse pressure. We pursued genome-wide interrogation in Stage 1 studies (N = 117 438) and follow-up on promising variants in Stage 2 studies (N = 293 787) in five ancestry groups. Through combined meta-analyses of Stages 1 and 2, we identified 84 known and 18 novel BP loci at genome-wide significance level (P < 5 × 10-8). Two novel loci were identified based on the 1DF test of interaction with educational attainment, while the remaining 16 loci were identified through the 2DF joint test of genetic and interaction effects. Ten novel loci were identified in individuals of African ancestry. Several novel loci show strong biological plausibility since they involve physiologic systems implicated in BP regulation. They include genes involved in the central nervous system-adrenal signaling axis (ZDHHC17, CADPS, PIK3C2G), vascular structure and function (GNB3, CDON), and renal function (HAS2 and HAS2-AS1, SLIT3). Collectively, these findings suggest a role of educational attainment or SES in further dissection of the genetic architecture of BP.
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| 3. |
- Li, Jian, et al.
(författare)
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A 3D extra-large-pore zeolite enabled by 1D-to-3D topotactic condensation of a chain silicate
- 2023
-
Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 379:6629, s. 283-287
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Tidskriftsartikel (refereegranskat)abstract
- Zeolites are microporous silicates with a large variety of applications as catalysts, adsorbents, and cation exchangers. Stable silica-based zeolites with increased porosity are in demand to allow adsorption and processing of large molecules but challenge our synthetic ability. We report a new, highly stable pure silica zeolite called ZEO-3, which has a multidimensional, interconnected system of extra-large pores open through windows made by 16 and 14 silicate tetrahedra, the least dense polymorph of silica known so far. This zeolite was formed by an unprecedented one-dimensional to three-dimensional (1D-to-3D) topotactic condensation of a chain silicate. With a specific surface area of more than 1000 square meters per gram, ZEO-3 showed a high performance for volatile organic compound abatement and recovery compared with other zeolites and metal-organic frameworks.
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| 4. |
- Tang, Hu, et al.
(författare)
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Boron-Rich Molybdenum Boride with Unusual Short-Range Vacancy Ordering, Anisotropic Hardness, and Superconductivity
- 2020
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Ingår i: Chemistry of Materials. - : AMER CHEMICAL SOC. - 0897-4756 .- 1520-5002. ; 32:1, s. 459-467
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Tidskriftsartikel (refereegranskat)abstract
- Determination of the structures of materials involving more light elements such as boron-rich compounds is challenging and technically important in understanding their varied compositions and superior functionalities. Here we resolve the long-standing uncertainties in structure and composition about the highest boride (termed MoB4, Mo1-xB3, or MoB3) through the rapid formation of large sized boron-rich molybdenum boride under pressure. Using high-quality single-crystal X-ray diffraction analysis and aberration-corrected scanning transmission electron microscopy, we reveal that boron-rich molybdenum boride with a composition of Mo0.757B3 exhibits P6(3)/mmc symmetry with a partial occupancy of 0.514 in 211 Mo sites (Mol), and direct observations reveal the short-range ordering of cation vacancies in (010) crystal planes. Large anisotropic Young's moduli and Vickers hardness are seen for Mo0.757B3, which may be attributed by its two-dimensional boron distributions. Mo0.757B3 is also found to be superconducting with a transition temperature (T-c) of 2.4 K, which was confirmed by measurements of resistivity and magnetic susceptibility. Theoretical calculations suggest that the partial occupancy of Mo atoms plays a crucial role in the emergence of superconductivity.
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| 5. |
- Bhat, Goutam, et al.
(författare)
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NTIRE 2022 Burst Super-Resolution Challenge
- 2022
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Ingår i: 2022 IEEE/CVF CONFERENCE ON COMPUTER VISION AND PATTERN RECOGNITION WORKSHOPS (CVPRW 2022). - : IEEE. - 9781665487399 - 9781665487405 ; , s. 1040-1060
-
Konferensbidrag (refereegranskat)abstract
- Burst super-resolution has received increased attention in recent years due to its applications in mobile photography. By merging information from multiple shifted images of a scene, burst super-resolution aims to recover details which otherwise cannot be obtained using a simple input image. This paper reviews the NTIRE 2022 challenge on burst super-resolution. In the challenge, the participants were tasked with generating a clean RGB image with 4x higher resolution, given a RAW noisy burst as input. That is, the methods need to perform joint denoising, demosaicking, and super-resolution. The challenge consisted of 2 tracks. Track 1 employed synthetic data, where pixel-accurate high-resolution ground truths are available. Track 2 on the other hand used real-world bursts captured from a handheld camera, along with approximately aligned reference images captured using a DSLR. 14 teams participated in the final testing phase. The top performing methods establish a new state-of-the-art on the burst super-resolution task.
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| 6. |
- Chen, Fei-Jian, et al.
(författare)
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Structure-direction towards the new large pore zeolite NUD-3
- 2021
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Ingår i: Chemical Communications. - : Royal Society of Chemistry (RSC). - 1359-7345 .- 1364-548X. ; 57:2, s. 191-194
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Tidskriftsartikel (refereegranskat)abstract
- The new zeolite NUD-3 possesses a three-dimensional system of large pore channels that is topologically identical to those of ITQ-21 and PKU-14. However, the three zeolites have distinctly different frameworks: a particular single 4-membered ring inside the denser portion of the zeolite is missing in PKU-14, disordered in ITQ-21 and fully ordered in NUD-3. We document these differences and use molecular simulations to unravel the mechanism by which a particular structure directing agent dication, 1,1′-(1,2-phenylenebis(methylene))bis(3-methylimidazolium), is able to orient this inner ring.
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| 7. |
- 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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| 8. |
- 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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| 9. |
- Lin, Qing-Fang, et al.
(författare)
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A stable aluminosilicate zeolite with intersecting three-dimensional extra-large pores
- 2021
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 374:6575, s. 1605-1608
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Tidskriftsartikel (refereegranskat)abstract
- Zeolites are crystalline porous materials with important industrial applications, including uses in catalytic and adsorption-separation processes. Access into and out of their inner confined space, where adsorption and reactions occur, is limited by their pore apertures. Stable multidimensional zeolites with larger pores able to process larger molecules are in demand in the fine chemical industry and for the oil processing on which the world still relies for fuels. Currently known extra-large-pore zeolites display poor stability and/or lack pore multidimensionality, limiting their usefulness. We report ZEO-1, a robust, fully connected aluminosilicate zeolite with mutually intersecting three-dimensional extra-large plus three-dimensional large pores. ZEO-1 is stable up to 1000 degrees C, has an extraordinary specific surface area (1000 square meters per gram), and shows potential as a catalytic cracking catalyst.
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| 10. |
- 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
-
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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| 11. |
- Cao, Wei, et al.
(författare)
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Ionic organic cage-encapsulated metal clusters for switchable catalysis
- 2021
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Ingår i: Cell Reports Physical Science. - : Elsevier BV. - 2666-3864. ; 2:9
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Tidskriftsartikel (refereegranskat)abstract
- The capability to build up stable, switchable catalysts for complex artificial systems that can mimic the responsiveness of biological systems to multiple triggers is highly desirable and challenging. Herein, we engineer such a system by physically locking catalytically active metal clusters (MCs) inside individual cationic molecular organic cages (I-Cages), where the responsive and task-specific counteranions of I-Cages impart MCs with a programmable gating effect. This allows for precise spatial and temporal control over chemical reactions by regulating accessibility of reagents to the MC sites. Following this strategy, we have successfully tailored catalytic activity of a series of model catalysis (e.g., methanolysis of ammonia borane, and the reduction of 4-nitroaniline) by employing light and pH stimuli, as well as their combination, for programmable-activity control.
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| 12. |
- Chen, Desui, et al.
(författare)
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Shelf-Stable Quantum-Dot Light-Emitting Diodes with High Operational Performance
- 2020
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Ingår i: Advanced Materials. - : Wiley-VCH Verlagsgesellschaft. - 0935-9648 .- 1521-4095. ; 32
-
Tidskriftsartikel (refereegranskat)abstract
- Quantum-dot light-emitting diodes (QLEDs) promise a new generation of high-performance, large-area, and cost-effective electroluminescent devices for both display and solid-state lighting technologies. However, a positive ageing process is generally required to improve device performance for state-of-the-art QLEDs. Here, it is revealed that the in situ reactions induced by organic acids in the commonly used encapsulation acrylic resin lead to positive ageing and, most importantly, the progression of in situ reactions inevitably results in negative ageing, i.e., deterioration of device performance after long-term shelf storage. In-depth mechanism studies focusing on the correlations between the in situ chemical reactions and the shelf-ageing behaviors of QLEDs inspire the design of an electron-transporting bilayer, which delivers both improved electrical conductivity and suppressed interfacial exciton quenching. This material innovation enables red QLEDs exhibiting neglectable changes of external quantum efficiency (>20.0%) and ultralong operational lifetime (T-95: 5500 h at 1000 nits) after storage for 180 days. This work provides design principles for oxide electron-transporting layers to realize shelf-stable and high-operational-performance QLEDs, representing a new starting point for both fundamental studies and practical applications.
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| 13. |
- Chen, Yuqing, et al.
(författare)
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Breaking solvation dominance of ethylene carbonate via molecular charge engineering enables lower temperature battery
- 2023
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Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 14
-
Tidskriftsartikel (refereegranskat)abstract
- Low temperatures severely impair the performance of lithium-ion batteries, which demand powerful electrolytes with wide liquidity ranges, facilitated ion diffusion, and lower desolvation energy. The keys lie in establishing mild interactions between Li+ and solvent molecules internally, which are hard to achieve in commercial ethylene-carbonate based electrolytes. Herein, we tailor the solvation structure with low-ε solvent-dominated coordination, and unlock ethylene-carbonate via electronegativity regulation of carbonyl oxygen. The modified electrolyte exhibits high ion conductivity (1.46 mS·cm−1) at −90 °C, and remains liquid at −110 °C. Consequently, 4.5 V graphite-based pouch cells achieve ~98% capacity over 200 cycles at −10 °C without lithium dendrite. These cells also retain ~60% of their room-temperature discharge capacity at −70 °C, and miraculously retain discharge functionality even at ~−100 °C after being fully charged at 25 °C. This strategy of disrupting solvation dominance of ethylene-carbonate through molecular charge engineering, opens new avenues for advanced electrolyte design.
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| 14. |
- Cheng, Shi-Ping, et al.
(författare)
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Haplotype-resolved genome assembly and allele-specific gene expression in cultivated ginger
- 2021
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Ingår i: Horticulture Research. - : Springer Nature. - 2052-7276. ; 8:1
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Tidskriftsartikel (refereegranskat)abstract
- Ginger (Zingiber officinale) is one of the most valued spice plants worldwide; it is prized for its culinary and folk medicinal applications and is therefore of high economic and cultural importance. Here, we present a haplotype-resolved, chromosome-scale assembly for diploid ginger anchored to 11 pseudochromosome pairs with a total length of 3.1 Gb. Remarkable structural variation was identified between haplotypes, and two inversions larger than 15 Mb on chromosome 4 may be associated with ginger infertility. We performed a comprehensive, spatiotemporal, genome-wide analysis of allelic expression patterns, revealing that most alleles are coordinately expressed. The alleles that exhibited the largest differences in expression showed closer proximity to transposable elements, greater coding sequence divergence, more relaxed selection pressure, and more transcription factor binding site differences. We also predicted the transcription factors potentially regulating 6-gingerol biosynthesis. Our allele-aware assembly provides a powerful platform for future functional genomics, molecular breeding, and genome editing in ginger.
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| 15. |
- Dai, Xize, et al.
(författare)
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Ageing state identification and analysis of AC submarine cable based 500 kV XLPE on high-voltage frequency dielectric response
- 2020
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Ingår i: IET Science, Measurement & Technology. - 1751-8822 .- 1751-8830. ; 14:8, s. 977-984
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Tidskriftsartikel (refereegranskat)abstract
- Carrying out the insulation condition measurement and analysis is important for the safe operation of the submarinecable. In this study, the high-voltage frequency dielectric response is used to identify the ageing state of the AC 500 kV cross-linked polyethylene (XLPE) submarine cable. The complex capacitance and tanδ in the low-frequency area for the new, thermal ageing, electro-thermal ageing cable all increase with the testing voltage increased from 200 to 2000 V. It is founded that the dielectric response at high voltage is more likely to detect the ageing differences. Based on the carbonyl index and the dielectric loss of the XLPE specimens at different position of the insulation layer, the non-uniform ageing phenomenon of the cable insulation is presented for the thermal ageing and electro-thermal ageing cable. The loss quantity parameter and its changing behaviour with testing voltage based on the frequency dielectric response could be used to identify the ageing state. The comparison of the modified Cole–Cole model parameter under 200 and 2000 V also indicates that the higher voltage dielectric response is helpful to identify the ageing differences.
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| 16. |
- Du, Hao, et al.
(författare)
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Recovery of lithium salt from spent lithium-ion battery by less polar solvent wash and water extraction
- 2023
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Ingår i: Carbon Neutralization. - : John Wiley & Sons. - 2769-3325 .- 2769-3325. ; 2:4, s. 416-424
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Tidskriftsartikel (refereegranskat)abstract
- The lithium hexafluorophosphate (LiPF6) in spent lithium-ion batteries (LIBs) is a potentially valuable resource and a significant environmental pollutant. Unfortunately, most of the LiPF6 in a spent LIB is difficult to extract because the electrolyte is strongly adsorbed by the cathode, anode, and separator. Storing extracted electrolyte is also challenging because it contains LiPF6, which promotes the decomposition of the solvent. Here we show that electrolytes in spent LIBs can be collected by a less polar solvent dimethyl carbonate (DMC) wash, and LiPF6 can be concentrated by simple aqueous extraction by lowering ethylene carbonate (EC) content in the recycled electrolyte. Due to the similar dielectric constant of EC and water, reducing the content of EC in LIB electrolytes, or even eliminating it, facilitates the separation of water and electrolyte, thus enabling the lithium salts in the electrolyte to be separated from the organic solvent. The lithium salt extracting efficiency achieved in this way can be as high as 99.8%, and fluorine and phosphorus of LiPF6 can be fixed in the form of stable metal fluoride and phosphate by hydrothermal method. The same strategy can be used in industrial waste electrolyte recycling by diluting the waste with DMC and extracting the resulting solution with water. This work thus reveals a new route for waste electrolyte treatment and will also support the development of advanced EC-free electrolytes for high-performance, safe, and easily recyclable LIBs.
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| 17. |
- Fenstermacher, M.E., et al.
(författare)
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DIII-D research advancing the physics basis for optimizing the tokamak approach to fusion energy
- 2022
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 0029-5515 .- 1741-4326. ; 62:4
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Tidskriftsartikel (refereegranskat)abstract
- DIII-D physics research addresses critical challenges for the operation of ITER and the next generation of fusion energy devices. This is done through a focus on innovations to provide solutions for high performance long pulse operation, coupled with fundamental plasma physics understanding and model validation, to drive scenario development by integrating high performance core and boundary plasmas. Substantial increases in off-axis current drive efficiency from an innovative top launch system for EC power, and in pressure broadening for Alfven eigenmode control from a co-/counter-I p steerable off-axis neutral beam, all improve the prospects for optimization of future long pulse/steady state high performance tokamak operation. Fundamental studies into the modes that drive the evolution of the pedestal pressure profile and electron vs ion heat flux validate predictive models of pedestal recovery after ELMs. Understanding the physics mechanisms of ELM control and density pumpout by 3D magnetic perturbation fields leads to confident predictions for ITER and future devices. Validated modeling of high-Z shattered pellet injection for disruption mitigation, runaway electron dissipation, and techniques for disruption prediction and avoidance including machine learning, give confidence in handling disruptivity for future devices. For the non-nuclear phase of ITER, two actuators are identified to lower the L-H threshold power in hydrogen plasmas. With this physics understanding and suite of capabilities, a high poloidal beta optimized-core scenario with an internal transport barrier that projects nearly to Q = 10 in ITER at ∼8 MA was coupled to a detached divertor, and a near super H-mode optimized-pedestal scenario with co-I p beam injection was coupled to a radiative divertor. The hybrid core scenario was achieved directly, without the need for anomalous current diffusion, using off-axis current drive actuators. Also, a controller to assess proximity to stability limits and regulate β N in the ITER baseline scenario, based on plasma response to probing 3D fields, was demonstrated. Finally, innovative tokamak operation using a negative triangularity shape showed many attractive features for future pilot plant operation.
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| 18. |
- Gao, Chao, et al.
(författare)
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Redox-triggered switching in three-dimensional covalent organic frameworks
- 2020
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- The tuning of molecular switches in solid state toward stimuli-responsive materials has attracted more and more attention in recent years. Herein, we report a switchable three-dimensional covalent organic framework (3D COF), which can undergo a reversible transformation through a hydroquinone/quinone redox reaction while retaining the crystallinity and porosity. Our results clearly show that the switching process gradually happened through the COF framework, with an almost quantitative conversion yield. In addition, the redox-triggered transformation will form different functional groups on the pore surface and modify the shape of pore channel, which can result in tunable gas separation property. This study strongly demonstrates 3D COFs can provide robust platforms for efficient tuning of molecular switches in solid state. More importantly, switching of these moieties in 3D COFs can remarkably modify the internal pore environment, which will thus enable the resulting materials with interesting stimuli-responsive properties. Tuning of molecular switches in solid state toward stimuli-responsive materials attracted attention in recent years but has not yet been realized in three-dimensional (3D) covalent organic frameworks (COFs). Herein, the authors demonstrate a stable and switchable 3D COF which undergoes reversible transformation through a hydroquinone/quinone redox reaction.
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| 19. |
- Gao, Chao, et al.
(författare)
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Twist Building Blocks from Planar to Tetrahedral for the Synthesis of Covalent Organic Frameworks
- 2020
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Ingår i: Journal of the American Chemical Society. - 0002-7863 .- 1520-5126. ; 142:8, s. 3718-3723
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Tidskriftsartikel (refereegranskat)abstract
- Rational construction of covalent organic frameworks (COFs) with novel structures still remains a challenge. Herein, we report the designed synthesis of two COFs, 2D-BPTA-COF and 3D-BMTA-COF, starting from biphenyl-based precursors but with different groups at the ortho positions. Both COFs exhibited high crystallinity and large surface area, and interestingly, 2D-BPTA-COF crystallizes into 2D sheets with AB stacking mode while 3D-BMTA-COF adopts a 7-fold interpenetrated structure with pts topology. This structural difference could be ascribed to the introduction of methyl groups in the building blocks, as the dihedral angle of biphenyl rings in 2D-BPTA-COF is similar to 0 degrees while in 3D-BMTA-COF it is similar to 60 degrees. Therefore, it is possible to synthesize COFs with different structures by twisting building blocks from planar to tetrahedral with steric hindrance. We believe this result represents a general and straightforward way to expand the diversity of tetrahedral nodes for constructing 3D COFs in the future, and moreover, a new tetrahedral node for constructing 3D COFs is now available.
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| 20. |
- Gao, Lingfeng, et al.
(författare)
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Emerging applications of MXenes for photodetection : Recent advances and future challenges
- 2022
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Ingår i: Materials Today. - : Elsevier. - 1369-7021 .- 1873-4103. ; 61, s. 169-190
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Tidskriftsartikel (refereegranskat)abstract
- The development and applications of transition metal carbides, nitrides and carbonitrides, commonly denoted as MXenes, have during the last few years rapidly expanded in various technological fields owing to their unique and controllable properties. These materials exhibit competing performance comparing with traditional materials and have created numerous opportunities for technology markets. Taking the advantage of excellent optoelectronic features, MXenes have been utilized for the construction of photodetectors with various structures and unique functionalities. While the appli-cation of MXenes in this area can be traced back to 2016, we have during the recent three years witnessed a dramatic development of MXene-based photodetectors, calling for a timely review to guideline their future direction. In this work, synthetic strategies of pristine MXenes are briefly introduced and their properties are discussed focusing on the optoelectronic aspects that are fundamental for the photoelectric conversion. Recent advances of MXene-based photodetectors are comprehensively summarized based on different types of MXenes and innovative designs of device construction. Finally, we provide perspectives for future challenges and opportunities of MXene-based photodetectors, which may enlighten their further development.
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| 21. |
- Gao, Yang, et al.
(författare)
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The Influence of Increased CO2 Concentrations on AMOC Interdecadal Variability Under the LGM Background
- 2024
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Ingår i: JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES. - 2169-897X .- 2169-8996. ; 129:3
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Tidskriftsartikel (refereegranskat)abstract
- This study explores the impact of rising CO2 levels on the Atlantic meridional overturning circulation's (AMOC) interdecadal variability within the context of the Last Glacial Maximum (LGM) background climate. Under heightened CO2 concentrations, the AMOC interdecadal variability intensifies dramatically, which is very different from the future warming case that shows a weakening of AMOC interdecadal variability in response to increased CO2 concentration. This unexpected phenomenon primarily results from the extensive retreat of sea ice, which exposes a larger portion of the ocean surface to efficiently feel the heat flux fluctuations from atmospheric processes. These findings underscore the significance of background climate conditions in shaping AMOC responses to increased CO2 and emphasize the necessity of considering these nuances to develop a more accurate understanding of AMOC dynamics in an evolving climate. Plain Language Summary The Atlantic meridional overturning circulation (AMOC) is an important component of the Earth system, and its interdecadal variability is predicted to be significantly weakened under future warming scenarios. In this paper, we analyze the response of AMOC interdecadal variability to rising CO2 levels under the background of the Last Glacial Maximum (LGM) and find that the AMOC interdecadal variability is intensified under increased CO2 , which is totally different from its response at the background of modern climate. Analyses suggest that this unexpected result is mainly caused by dramatic sea ice retreat, which exposes much seawater to efficiently receive large fluctuations of heat flux from atmospheric forcing. The findings reveal that the response of AMOC to increased CO2 and relevant dominant mechanism differs significantly under different climate conditions.
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| 22. |
- Gao, Zhu, et al.
(författare)
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Interfacial Ti-S Bond Modulated S-Scheme MOF/Covalent Triazine Framework Nanosheet Heterojunctions for Photocatalytic C-H Functionalization
- 2023
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Ingår i: Angewandte Chemie International Edition. - 1433-7851 .- 1521-3773. ; 62:27
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Tidskriftsartikel (refereegranskat)abstract
- Constructing photocatalyst systems to functionalize the inert C−H bonds has attracted extensive research interest. However, purposeful modulation of interfacial charge transfer in heterostructures remains a challenge, as it usually suffers from sluggish kinetics. Reported herein is an easy strategy to construct the heteroatom-induced interface for developing the titanium-organic frameworks (MOF-902) @ thiophene-based covalent triazine frameworks (CTF-Th) nanosheets S-scheme heterojunctions with controllable oxygen vacancies (OVs). Specifically, Ti atoms were first anchored onto the heteroatom site of CTF-Th nanosheets, and then grown into MOF-902 via an interfacial Ti−S linkage, generating OVs. Using in situ X-ray photoelectron spectroscopy (XPS), extended X-ray absorption fine structure (EXAFS) spectroscopy and density functional theory (DFT) calculations, the enhanced interfacial charge separation and transfer induced by moderate OVs in the pre-designed S-scheme nanosheets was validated. The heterostructures exhibited an improved efficiency in photocatalytic C3-acylation of indoles under mild conditions with a yield 8.2 times larger than pristine CTF-Th or MOF-902 and enabled an extended scope of substrates (15 examples). This performance is superior to state-of-the-art photocatalyst and can be retained, without significant loss, after 12 consecutive cycles.
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| 23. |
- Gao, Zihao Rei, et al.
(författare)
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Dication Containing Three Aromatic Ring Structure-Directs toward a Chiral Zeolite, Spans Three Cavities, and Effectively Traps Water
- 2022
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Ingår i: Chemistry of Materials. - : American Chemical Society (ACS). - 0897-4756 .- 1520-5002. ; 34:7, s. 3197-3205
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Tidskriftsartikel (refereegranskat)abstract
- The chiral zeolite STW has been synthesized using a large dication containing three aromatic rings (two imidazolium moieties plus a benzene one). The integrity of the occluded organics is proven by 1H and 13C liquid NMR of the zeolite dissolved in HF/D2O. Molecular simulations strongly suggest that each aromatic ring is located in a different cavity so that each dication crosses two medium pore 10-membered-ring (MR) windows. This is confirmed by Rietveld refinement against synchrotron powder X-ray diffraction data, which suggests that there is also trapped water in the cavities, explaining a significant excess of H found in this material. The presence of water is very soundly confirmed by Fourier-transform infrared experiments, which also show that this water cannot leave the zeolite even after heating at 180 °C under vacuum. Molecular simulations allow us to conclude that this is due to the blockage of the 10 and 8MR windows by the occluded organics. The peculiar situation of an organic structure-directing agent spanning three cavities has important implications for the structure-direction concept that are briefly discussed. Several chiral derivatives of this dication have also been studied, and their possibility to enantioselectively direct the crystallization of STW has been analyzed.
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| 24. |
- Gao, Zihao Rei, et al.
(författare)
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HPM-14 : A New Germanosilicate Zeolite with Interconnected Extra-Large Pores Plus Odd-Membered and Small Pores
- 2021
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Ingår i: Angewandte Chemie International Edition. - : Wiley. - 1433-7851 .- 1521-3773. ; 60:7, s. 3438-3442
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Tidskriftsartikel (refereegranskat)abstract
- HPM-14 is a new extra-large pore zeolite synthesized using imidazolium-based organic structure-directing agents (SDAs), fluoride anions, and germanium and silicon as tetrahedral components of the framework. Owing to the presence of stacking disorder, the structure elucidation of HPM-14 was challenging, and different techniques were necessary to clarify the details of the structure and to understand the nature of the disorder. The structure has been solved by three-dimensional electron-diffraction technique (3D ED) and consists of an intergrowth of two polymorphs possessing a three-dimensional channel system, including an extra-large pore opened through windows made up of sixteen tetrahedral atoms (16-membered ring, 16MR) as well as two additional sets of odd-membered (9MR) and small (8MR) pores. The intergrowth has been studied by scanning transmission electron microscopy (C-s-STEM) and powder X-ray diffraction simulations (DIFFaX), which show a large predominance of the monoclinic polymorph A.
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| 25. |
- Gao, Zihao Rei, et al.
(författare)
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HPM-16, a Stable Interrupted Zeolite with a Multidimensional Mixed Medium-Large Pore System Containing Supercages
- 2021
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Ingår i: Angewandte Chemie International Edition. - : Wiley. - 1433-7851 .- 1521-3773. ; 60:37, s. 20249-20252
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Tidskriftsartikel (refereegranskat)abstract
- HPM-16 is a highly porous germanosilicate zeolite with an interrupted framework that contains a three-dimensional system of 12+10x10(12)x12+10-membered ring (MR) pores. The 10(12) MR pore in the b direction is a 10 MR pore with long 12 MR stretches forming 30 angstrom long tubular supercages. Along one direction the 10 MR pores are fused, meaning that the separation between adjacent pores consists of a single tetrahedron that is, additionally, connected to only three additional tetrahedra (a Q(3)). These fused pores are thus decorated by T-OH groups along the whole diffusion path, creating a hydrophilic region embedded in an otherwise essentially hydrophobic environment. The structure is built from highly porous 12x12x12 MR uninterrupted layers that are connected to each other through Q(3) producing a second system of 10x10x10 MR pores. This zeolite can be extensively degermanated yielding a material with high thermal stability, despite its interrupted nature.
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