| 1. |
- Li, Xiaoting, et al.
(författare)
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Nano-confinement-inspired metal organic framework/polymer composite separation membranes
- 2020
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Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry (RSC). - 2050-7488 .- 2050-7496. ; 8:33, s. 17212-17218
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Tidskriftsartikel (refereegranskat)abstract
- A defect-free, robust and selective barrier is essential for manufacturing membranes with targeted high permeability and selectivity. Here we report a new route to engineering a separation composite membrane by confining both channels in nanoscale metal organic frameworks (MOFs) and charges in a polyelectrolyte in the inner space of a porous supportviaa counter-diffusion method. A simple thermal annealing treatment of the interface between the MOF, polymer and support favorably reduced voids inside this nano-confinement environment. As this composite membrane combines both the support and barrier as one, it minimizes mass transfer resistance of water molecules. In a separation test, it readily achieved the state-of-the-art permeance. This simple chemical approach to upgrade membrane structures will offer wide opportunities in separation devices.
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| 2. |
- Shi, Tian-Le, et al.
(författare)
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High-quality genome assembly enables prediction of allele-specific gene expression in hybrid poplar
- 2024
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Ingår i: Plant Physiology. - : Oxford University Press. - 0032-0889 .- 1532-2548. ; 195:1, s. 652-670
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Tidskriftsartikel (refereegranskat)abstract
- Poplar (Populus) is a well-established model system for tree genomics and molecular breeding, and hybrid poplar is widely used in forest plantations. However, distinguishing its diploid homologous chromosomes is difficult, complicating advanced functional studies on specific alleles. In this study, we applied a trio-binning design and PacBio high-fidelity long-read sequencing to obtain haplotype-phased telomere-to-telomere genome assemblies for the 2 parents of the well-studied F1 hybrid “84K” (Populus alba × Populus tremula var. glandulosa). Almost all chromosomes, including the telomeres and centromeres, were completely assembled for each haplotype subgenome apart from 2 small gaps on one chromosome. By incorporating information from these haplotype assemblies and extensive RNA-seq data, we analyzed gene expression patterns between the 2 subgenomes and alleles. Transcription bias at the subgenome level was not uncovered, but extensive-expression differences were detected between alleles. We developed machine-learning (ML) models to predict allele-specific expression (ASE) with high accuracy and identified underlying genome features most highly influencing ASE. One of our models with 15 predictor variables achieved 77% accuracy on the training set and 74% accuracy on the testing set. ML models identified gene body CHG methylation, sequence divergence, and transposon occupancy both upstream and downstream of alleles as important factors for ASE. Our haplotype-phased genome assemblies and ML strategy highlight an avenue for functional studies in Populus and provide additional tools for studying ASE and heterosis in hybrids.
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| 3. |
- Thompson, Paul M., et al.
(författare)
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The ENIGMA Consortium : large-scale collaborative analyses of neuroimaging and genetic data
- 2014
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Ingår i: BRAIN IMAGING BEHAV. - : Springer Science and Business Media LLC. - 1931-7557 .- 1931-7565. ; 8:2, s. 153-182
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Tidskriftsartikel (refereegranskat)abstract
- The Enhancing NeuroImaging Genetics through Meta-Analysis (ENIGMA) Consortium is a collaborative network of researchers working together on a range of large-scale studies that integrate data from 70 institutions worldwide. Organized into Working Groups that tackle questions in neuroscience, genetics, and medicine, ENIGMA studies have analyzed neuroimaging data from over 12,826 subjects. In addition, data from 12,171 individuals were provided by the CHARGE consortium for replication of findings, in a total of 24,997 subjects. By meta-analyzing results from many sites, ENIGMA has detected factors that affect the brain that no individual site could detect on its own, and that require larger numbers of subjects than any individual neuroimaging study has currently collected. ENIGMA's first project was a genome-wide association study identifying common variants in the genome associated with hippocampal volume or intracranial volume. Continuing work is exploring genetic associations with subcortical volumes (ENIGMA2) and white matter microstructure (ENIGMA-DTI). Working groups also focus on understanding how schizophrenia, bipolar illness, major depression and attention deficit/hyperactivity disorder (ADHD) affect the brain. We review the current progress of the ENIGMA Consortium, along with challenges and unexpected discoveries made on the way.
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| 4. |
- Benson, Tyler W., et al.
(författare)
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Gut Microbiota-Derived Trimethylamine N-Oxide Contributes to Abdominal Aortic Aneurysm Through Inflammatory and Apoptotic Mechanisms
- 2023
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Ingår i: Circulation. - : Lippincott Williams & Wilkins. - 0009-7322 .- 1524-4539. ; 147:14, s. 1079-1096
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Tidskriftsartikel (refereegranskat)abstract
- Background:Large-scale human and mechanistic mouse studies indicate a strong relationship between the microbiome-dependent metabolite trimethylamine N-oxide (TMAO) and several cardiometabolic diseases. This study aims to investigate the role of TMAO in the pathogenesis of abdominal aortic aneurysm (AAA) and target its parent microbes as a potential pharmacological intervention.Methods:TMAO and choline metabolites were examined in plasma samples, with associated clinical data, from 2 independent patient cohorts (N=2129 total). Mice were fed a high-choline diet and underwent 2 murine AAA models, angiotensin II infusion in low-density lipoprotein receptor-deficient (Ldlr(-/-)) mice or topical porcine pancreatic elastase in C57BL/6J mice. Gut microbial production of TMAO was inhibited through broad-spectrum antibiotics, targeted inhibition of the gut microbial choline TMA lyase (CutC/D) with fluoromethylcholine, or the use of mice genetically deficient in flavin monooxygenase 3 (Fmo3(-/-)). Finally, RNA sequencing of in vitro human vascular smooth muscle cells and in vivo mouse aortas was used to investigate how TMAO affects AAA.Results:Elevated TMAO was associated with increased AAA incidence and growth in both patient cohorts studied. Dietary choline supplementation augmented plasma TMAO and aortic diameter in both mouse models of AAA, which was suppressed with poorly absorbed oral broad-spectrum antibiotics. Treatment with fluoromethylcholine ablated TMAO production, attenuated choline-augmented aneurysm initiation, and halted progression of an established aneurysm model. In addition, Fmo3(-/-) mice had reduced plasma TMAO and aortic diameters and were protected from AAA rupture compared with wild-type mice. RNA sequencing and functional analyses revealed choline supplementation in mice or TMAO treatment of human vascular smooth muscle cells-augmented gene pathways associated with the endoplasmic reticulum stress response, specifically the endoplasmic reticulum stress kinase PERK.Conclusions:These results define a role for gut microbiota-generated TMAO in AAA formation through upregulation of endoplasmic reticulum stress-related pathways in the aortic wall. In addition, inhibition of microbiome-derived TMAO may serve as a novel therapeutic approach for AAA treatment where none currently exist.
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| 5. |
- Hibar, Derrek P., et al.
(författare)
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Novel genetic loci associated with hippocampal volume
- 2017
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- The hippocampal formation is a brain structure integrally involved in episodic memory, spatial navigation, cognition and stress responsiveness. Structural abnormalities in hippocampal volume and shape are found in several common neuropsychiatric disorders. To identify the genetic underpinnings of hippocampal structure here we perform a genome-wide association study (GWAS) of 33,536 individuals and discover six independent loci significantly associated with hippocampal volume, four of them novel. Of the novel loci, three lie within genes (ASTN2, DPP4 and MAST4) and one is found 200 kb upstream of SHH. A hippocampal subfield analysis shows that a locus within the MSRB3 gene shows evidence of a localized effect along the dentate gyrus, subiculum, CA1 and fissure. Further, we show that genetic variants associated with decreased hippocampal volume are also associated with increased risk for Alzheimer's disease (r(g) = -0.155). Our findings suggest novel biological pathways through which human genetic variation influences hippocampal volume and risk for neuropsychiatric illness.
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| 6. |
- Ji, Haoran, et al.
(författare)
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Peer-to-Peer Electricity Trading of Interconnected Flexible Distribution Networks Based on Distributed Ledger
- 2022
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Ingår i: IEEE Transactions on Industrial Informatics. - : IEEE Computer Society. - 1551-3203 .- 1941-0050. ; 18:9, s. 5949-5960
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Tidskriftsartikel (refereegranskat)abstract
- The condition of power imbalance in flexible distribution networks (FDNs) is deteriorated due to the high penetration of distributed generators (DGs). Through peer-to-peer (P2P) electricity trading, multiple regions interconnected by soft open points (SOPs) can flexibly exchange power to alleviate power imbalance. As the physical foundation of P2P transactions, SOP regulation guarantees accurate instruction execution. Besides, smart contracts based on distributed ledger technology (DLT) facilitate highly credible P2P transactions. Oriented for the economic operation of interconnected FDNs, this paper proposes a DLT-based P2P electricity trading method based on intelligent SOP regulation. First, a smart contract is designed for P2P transactions of FDNs, in which trading solutions are automatically settled with a modified highest combined offer (HCO) principle. Then, a trading platform is built for the P2P electricity trading of interconnected FDNs. Finally, the effectiveness of the proposed method is verified on a practical FDN with four-terminal SOPs in Tianjin.
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| 7. |
- Li, Xinmin, et al.
(författare)
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A pin on disc study of the tribology characteristics of sintered versus standard gear materials
- 2014
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Konferensbidrag (populärvet., debatt m.m.)abstract
- Powder metallurgy allows complex component geometries which includes gears. There is however a lack of knowledge of the tribological performance of powder material gears compared to gears manufactured from standard gear materials. In this study, a pin on disc machine was used to simulate the sliding part of gear tooth contact both in boundary and mixed lubricated regions. A comparative study of the tribology characteristics of two kind of sintered gear materials with a standard gear material was performed. The comparison comprised of damage mechanisms, wear, friction and running-in between these materials in different pin on disc configuration (standard vs standard, sintered versus sintered and sintered versus standard). For the same gear materials combinations [RS-RS (16MnCr5), AQ-AQ (Distaloy AQ+0.2%C) and Mo-Mo (Astaloy 85Mo+0.2%C)], RS gear material has a lower friction coefficient. When it comes to PM and RS material combinations, both of the PM materials showed a lower friction coefficient, when the pins are made of PM materials in contrast if we have RS pin. Also for the wear rate, RS material always shows the lowest wear rate no matter the disc material. AQ and Mo gear materials have nearly the same wear rate. A distinct difference between different material combinations, both in friction and in wear rate, is observed during the running-in phase.
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| 8. |
- Li, Xinmin, et al.
(författare)
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A pin-on-disc study of the tribology characteristics of sintered versus standard steel gear materials
- 2015
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Ingår i: Wear. - : Elsevier. - 0043-1648 .- 1873-2577.
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- Though powder metallurgy (PM) allows manufacturing of complex components, including gears, we lack knowledge of the tribological performance of PM versus standard steel gear materials. Using a pin-on-disc machine, we simulate the sliding part of gear tooth contact in boundary and mixed lubricated regions, comparing the tribological characteristics of two sintered gear materials with those of a standard gear material. The comparison considered damage mechanisms, wear, and friction between these materials in different configurations (i.e., standard versus standard, sintered versus sintered, and sintered versus standard). The results indicate that, for pairings of the same gear materials, i.e., RS–RS (16MnCr5), AQ–AQ (Distaloy AQ+0.2% C), and Mo–Mo (Astaloy 85Mo+0.2% C), RS has a lower friction coefficient. For PM and RS combinations, both PM pins have lower friction coefficients with RS disc material than do RS pins with PM disc materials. For the wear coefficient, at low and high speeds, RS pins always display better wear resistance than do AQ or Mo pins because of their high hardness and compacted microstructure. For RS–PM combinations, Mo pins display higher wear resistance than do AQ pins because their larger and more numerous pores enable good lubrication. Pins in the Mo–RS combination displayed the highest wear resistance, mainly because the pores in Mo discs hold lubricant, lubricating the contact surface and preventing adhesive wear. For the RS pin in the Mo–RS combination and the AQ pin in RS–AQ, the damage mechanism is slight adhesive wear and scuffing. For pins in the PM–PM, RS–PM, AQ–RS, and RS–RS combinations, the damage mechanism is a heavier scuffing-type adhesive wear.
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| 9. |
- Li, Xinmin, et al.
(författare)
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A Pin-on-Disk Study of the Tribological Properties of Polyoxymethylene (POM) Gear Materials
- 2024
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9456 .- 1557-9662. ; 73
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Tidskriftsartikel (refereegranskat)abstract
- Polyoxymethylene (POM) is now widely used as a gear material due to its excellent mechanical properties. There have been several studies on the tribology of POM; however, most of them focused solely on the material itself without integrating practical applications. This study investigates the tribological properties of POM-POM combinations in conjunction with the application of POM gears. Using a pin-on-disk machine, we simulate the sliding part of gear meshing. The influences of contact pressures (40 and 50 MPa), sliding speed (0.1 and 0.5 m/s), and lubrication on the tribological performance of POM pin sliding against POM disk were studied. The results showed that grease can reduce adhesion between sliding surfaces and effectively improve the tribological performance of the POM-POM combination. The friction coefficient decreases with increasing contact pressure, which is consistent with the existing models of the frictional behavior of polymer-polymer systems. The wear coefficient exhibits contrasting relationships with increasing contact pressure at high and low velocities. Because the wear mechanism changes from predominantly abrasion at low velocity to adhesion-peeling off at high velocity. Both the friction and wear coefficients decrease with increasing sliding velocity. The specific mechanisms of the influence of different lubrication conditions, pressures, velocities, and PV values on friction and wear are described and discussed throughout this article.
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| 10. |
- Li, Xinmin, et al.
(författare)
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A study of the efficiency of spur gears made of powder metallurgy materials - ground versus super-finished surfaces
- 2016
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Ingår i: Tribology International. - : Elsevier. - 0301-679X .- 1879-2464. ; 95:1, s. 211-220
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Tidskriftsartikel (refereegranskat)abstract
- Power loss is one of the main concerns in gear transmission systems. In this study a recirculating power back-to-back FZG test rig was used to investigate the efficiency of spur gears made of powder metallurgy (PM) material using two different surface manufacturing methods (ground and super-finished). The results were compared with previously presented results of standard gear material from the same test rig. The influence of the material (Wrought steel or PM) and surface roughness on the gear mesh efficiency and the total efficiency of the gearbox were analyzed in detail. The Young's modulus for PM materials is lower than for conventional gear steel. This may influence gear tooth bending and the efficiency of the gear transmission. Gear contact simulation results showed that the influence of gear tooth bending on PM gear transmission efficiency can be ignored in the FZG gear geometry. Higher surface energy combined with a smoother surface led to a lower transmission efficiency for the super-finished powder metallurgy gear combination compared to the standard gear material.
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