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2. |
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- 2019
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Journal article (peer-reviewed)
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3. |
- Cao, Jian, et al.
(author)
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Heterogeneous consecutive reaction kinetics of direct oxidation of H2 to H2O2: Effect and regulation of confined mass transfer
- 2023
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In: Chemical Engineering Journal. - : Elsevier. - 1385-8947 .- 1873-3212. ; 455
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Journal article (peer-reviewed)abstract
- Porous catalysts in heterogeneous reactions have played an important role in the modern chemical industry, but it is still challenging to quantitatively describe mass transfer and surface reaction behaviors of reactants in nano-confined space. Direct synthesis of hydrogen peroxide (H2O2) is considered as an attractive alternative to anthraquinone oxidation process, while the confined mass transfer of H2O2 in porous catalysts limits the reactivity. In this work, taking the consecutive reaction of H2O2 synthesis as an example, a quantitative method in modeling the effects of confined mass transfer on the reactivity was studied. More specifically, calorimetry was developed to characterize the confined structures of porous carbon experimentally, the linear nonequilibrium thermodynamics and the statistical mechanics method were further combined. Then, the heterogeneous consecutive reaction kinetics and the Thiele modulus influenced by confined mass transfer were modeled. Consequently, regulation strategies were proposed with the help of theoretical models. The optimized catalyst with biological skeleton carbon support and 0.5 wt% palladium loading shows an excellent catalytic performance. Lastly, for the mesoscience in heterogeneous reaction, the resistance was explored as a quantitative descriptor to compromise in the competition between mass transfer and surface reaction. The mesoscale structures were considered as the dynamic spatiotemporal distribution of substance concentrations, and the resistance minimization multi-scale (RMMS) model was proposed.
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4. |
- Gao, Qingwei, et al.
(author)
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Effect of water concentration on the microstructures of choline chloride/urea (1:2) /water mixture
- 2018
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In: Fluid Phase Equilibria. - : Elsevier. - 0378-3812 .- 1879-0224. ; 470, s. 134-139
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Journal article (peer-reviewed)abstract
- Molecular dynamics was utilized to investigate the properties of ChCl/urea (1:2)/water mixtures from pure ChCl/urea to infinitely dilute solution. To further study the mechanism at molecular scale, the local microstructure variation in the mixtures with the increase of water content was analyzed in detail. Simulation results showed that neither choline cations nor chloride anions are saturated by the coordinated water molecules, even when the water molar fraction reaches 0.9. The hydration number proportions for different ions indicated that the hydration strength of chloride anion is stronger than that of choline cation, which may play greater effects on the properties of mixtures. This result is further confirmed by the analysis of interaction energy between cation (anion) and water molecules. Moreover, the ion pairing between choline cations and chloride anions is a dominant factor to affect the solution properties at lower water content, whereas the hydration turns to be the dominant factor with increasing water content. The competition between ion pairing and ionic hydration could be the intrinsic mechanism resulting in non-ideal properties.
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5. |
- Ali, Asad, et al.
(author)
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Emerging strategies and developments in oxygen reduction reaction using high-performance platinum-based electrocatalysts
- 2024
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In: Nano Reseach. - : Tsinghua University Press. - 1998-0124 .- 1998-0000. ; 17:5, s. 3516-3532
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Research review (peer-reviewed)abstract
- The global practical implementation of proton exchange membrane fuel cells (PEMFCs) heavily relies on the advancement of highly effective platinum (Pt)-based electrocatalysts for the oxygen reduction reaction (ORR). To achieve high ORR performance, electrocatalysts with highly accessible reactive surfaces are needed to promote the uncovering of active positions for easy mass transportation. In this critical review, we introduce different approaches for the emerging development of effective ORR electrocatalysts, which offer high activity and durability. The strategies, including morphological engineering, geometric configuration modification via supporting materials, alloys regulation, core-shell, and confinement engineering of single atom electrocatalysts (SAEs), are discussed in line with the goals and requirements of ORR performance enhancement. We review the ongoing development of Pt electrocatalysts based on the syntheses, nanoarchitecture, electrochemical performances, and stability. We eventually explore the obstacles and research directions on further developing more effective electrocatalysts.
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6. |
- Ali, Asad, et al.
(author)
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Gram-scale production of in-situ generated iron carbide nanoparticles encapsulated via nitrogen and phosphorous co-doped bamboo-like carbon nanotubes for oxygen evolution reaction
- 2023
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In: Materials Science for Energy Technologies. - : Elsevier. - 2589-2991. ; 6, s. 301-309
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Journal article (peer-reviewed)abstract
- Optimizing electrocatalytic activity and recognizing the most reactive sites for oxygen evolution reaction (OER) electrocatalysts are valuable to the order of renewable power. In this research article, we explored an innovative in-situ annealing technique for constructing iron carbide nanoparticles (Fe3C NPs) encapsulated via nitrogen and phosphorous doped bamboo-shape carbon nanotubes (NP-CNTs) for OER. Interestingly, the constructed Fe3C NPs@NP-CNT-800 composite exhibited remarkable electrochemical operation and offered a stable current density of 10 mA/cm2 at a lower overpotential (280 mV) in an alkaline solution. Furthermore, an innovative Fe3C NPs@N,P-CNT-800 hybrid surpassed the standard RuO2 electrocatalyst in terms of OER performance and showed negligible degradation in chronoamperometric (21 h) and chronopotentiometry (3000 cycles) analyses. The remarkable performance and stability are ascribed to the Fe3C NPs, novel tubular bamboo-like morphology of its carbon materials, and heteroatom doping, which contribute to the electrochemical interfaces, large surface area, active catalytic sites, and rapid charge transfer kinetics.
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7. |
- An, Rong, et al.
(author)
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Atomic force microscopy probing interactions and microstructures of ionic liquids at solid surfaces
- 2022
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In: Nanoscale. - : Royal Society of Chemistry. - 2040-3364 .- 2040-3372. ; 14:31, s. 11098-11128
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Research review (peer-reviewed)abstract
- Ionic liquids (ILs) are room temperature molten salts that possess preeminent physicochemical properties and have shown great potential in many applications. However, the use of ILs in surface-dependent processes, e.g. energy storage, is hindered by the lack of a systematic understanding of the IL interfacial microstructure. ILs on the solid surface display rich ordering, arising from coulombic, van der Waals, solvophobic interactions, etc., all giving near-surface ILs distinct microstructures. Therefore, it is highly important to clarify the interactions of ILs with solid surfaces at the nanoscale to understand the microstructure and mechanism, providing quantitative structure–property relationships. Atomic force microscopy (AFM) opens a surface-sensitive way to probe the interaction force of ILs with solid surfaces in the layers from sub-nanometers to micrometers. Herein, this review showcases the recent progress of AFM in probing interactions and microstructures of ILs at solid interfaces, and the influence of IL characteristics, surface properties and external stimuli is thereafter discussed. Finally, a summary and perspectives are established, in which, the necessities of the quantification of IL–solid interactions at the molecular level, the development of in situ techniques closely coupled with AFM for probing IL–solid interfaces, and the combination of experiments and simulations are argued.
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8. |
- Bansal, Sheel, et al.
(author)
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Practical Guide to Measuring Wetland Carbon Pools and Fluxes
- 2023
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In: Wetlands (Wilmington, N.C.). - : SPRINGER. - 0277-5212 .- 1943-6246. ; 43:8
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Research review (peer-reviewed)abstract
- Wetlands cover a small portion of the world, but have disproportionate influence on global carbon (C) sequestration, carbon dioxide and methane emissions, and aquatic C fluxes. However, the underlying biogeochemical processes that affect wetland C pools and fluxes are complex and dynamic, making measurements of wetland C challenging. Over decades of research, many observational, experimental, and analytical approaches have been developed to understand and quantify pools and fluxes of wetland C. Sampling approaches range in their representation of wetland C from short to long timeframes and local to landscape spatial scales. This review summarizes common and cutting-edge methodological approaches for quantifying wetland C pools and fluxes. We first define each of the major C pools and fluxes and provide rationale for their importance to wetland C dynamics. For each approach, we clarify what component of wetland C is measured and its spatial and temporal representativeness and constraints. We describe practical considerations for each approach, such as where and when an approach is typically used, who can conduct the measurements (expertise, training requirements), and how approaches are conducted, including considerations on equipment complexity and costs. Finally, we review key covariates and ancillary measurements that enhance the interpretation of findings and facilitate model development. The protocols that we describe to measure soil, water, vegetation, and gases are also relevant for related disciplines such as ecology. Improved quality and consistency of data collection and reporting across studies will help reduce global uncertainties and develop management strategies to use wetlands as nature-based climate solutions.
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9. |
- Butler, Anne M., et al.
(author)
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Novel Loci Associated With PR Interval in a Genome-Wide Association Study of 10 African American Cohorts
- 2012
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In: Circulation: Cardiovascular Genetics. - 1942-325X. ; 5:6, s. 639-646
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Journal article (peer-reviewed)abstract
- Background-The PR interval, as measured by the resting, standard 12-lead ECG, reflects the duration of atrial/atrioventricular nodal depolarization. Substantial evidence exists for a genetic contribution to PR, including genome-wide association studies that have identified common genetic variants at 9 loci influencing PR in populations of European and Asian descent. However, few studies have examined loci associated with PR in African Americans. Methods and Results-We present results from the largest genome-wide association study to date of PR in 13 415 adults of African descent from 10 cohorts. We tested for association between PR (ms) and approximate to 2.8 million genotyped and imputed single-nucleotide polymorphisms. Imputation was performed using HapMap 2 YRI and CEU panels. Study-specific results, adjusted for global ancestry and clinical correlates of PR, were meta-analyzed using the inverse variance method. Variation in genome-wide test statistic distributions was noted within studies (lambda range: 0.9-1.1), although not after genomic control correction was applied to the overall meta-analysis (lambda: 1.008). In addition to generalizing previously reported associations with MEIS1, SCN5A, ARHGAP24, CAV1, and TBX5 to African American populations at the genome-wide significance level (P<5.0x10(-8)), we also identified a novel locus: ITGA9, located in a region previously implicated in SCN5A expression. The 3p21 region harboring SCN5A also contained 2 additional independent secondary signals influencing PR (P<5.0x10-8). Conclusions-This study demonstrates the ability to map novel loci in African Americans as well as the generalizability of loci associated with PR across populations of African, European, and Asian descent. (Circ Cardiovasc Genet. 2012;5:639-646.)
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10. |
- Chen, Jingjing, et al.
(author)
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Slippage on Porous Spherical Superhydrophobic Surface Revolutionizes Heat Transfer of Non-Newtonian Fluid
- 2022
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In: Advanced Materials Interfaces. - : John Wiley & Sons. - 2196-7350. ; 9:34
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Journal article (peer-reviewed)abstract
- In this study, a new strategy to achieve high-efficient heat transfer for non-Newtonian fluids with slippage using a stably prepared superhydrophobic coating is presented. A superhydrophobic coating is prepared on the inner surface of a sleeve at specific shear stress. The slippage and heat-transfer processes of the typical non-Newtonian fluid–1% carboxymethyl cellulose solutions on the superhydrophobic coating are investigated simultaneously. A novel porous spherical type of superhydrophobic coating with a contact angle of 168° is obtained. It is found that the shear stress in electrodeposition is a key parameter to control the morphology and wetting ability of the superhydrophobic coating. The slip length and enhancement factor of heat transfer for the non-Newtonian fluid on the coating are found in a range of 20–900 µm and 1.47 experimentally. A new parameter is proposed as Reynolds number Re divided by the dimensionless slip length ls* (Re/ls*) for the heat-transfer enhancement with slippage, which can be used as the guide for designing coating and selecting the operating conditions. The Re/ls* is <4, which can enhance the heat transfer via the slippage.
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11. |
- Chen, Jian, et al.
(author)
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Zika virus infects renal proximal tubular epithelial cells with prolonged persistency and cytopathic effects
- 2017
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In: Emerging Microbes & Infections. - : NATURE PUBLISHING GROUP. - 2222-1751. ; 6
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Journal article (peer-reviewed)abstract
- Zika virus (ZIKV) infection can cause fetal developmental abnormalities and Guillain-Barre syndrome in adults. Although progress has been made in understanding the link between ZIKV infection and microcephaly, the pathology of ZIKV, particularly the viral reservoirs in human, remains poorly understood. Several studies have shown that compared to serum samples, patients' urine samples often have a longer duration of ZIKV persistency and higher viral load. This finding suggests that an independent viral reservoir may exist in the human urinary system. Despite the clinical observations, the host cells of ZIKV in the human urinary system are poorly characterized. In this study, we demonstrate that ZIKV can infect renal proximal tubular epithelial cells (RPTEpiCs) in immunodeficient mice in vivo and in both immortalized and primary human renal proximal tubular epithelial cells (hRPTEpiCs) in vitro. Importantly, ZIKV infection in mouse kidneys caused caspase-3-mediated apoptosis of renal cells. Similarly, in vitro infection of immortalized and primary hRPTEpiCs resulted in notable cytopathic effects. Consistent with the clinical observations, we found that ZIKV infection can persist with prolonged duration in hRPTEpiCs. RNA-Seq analyses of infected hRPTEpiCs revealed a large number of transcriptional changes in response to ZIKV infection, including type I interferon signaling genes and anti-viral response genes. Our results suggest that hRPTEpiCs are a potential reservoir of ZIKV in the human urinary system, providing a possible explanation for the prolonged persistency of ZIKV in patients' urine.
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12. |
- Chen, Xiren, et al.
(author)
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Bi-Induced Electron Concentration Enhancement Being Responsible for Photoluminescence Blueshift and Broadening in InAs Films
- 2019
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In: Physica Status Solidi (B): Basic Research. - : Wiley. - 1521-3951 .- 0370-1972. ; 256:5
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Journal article (peer-reviewed)abstract
- Photoluminescence (PL) study is conducted on InAs films molecular beam epitaxially grown on GaAs substrates with different Bi flux levels. A PL peak blueshift accompanied by linewidth broadening is found with the increase of Bi/As flux ratio, in contrast to the common Bi isoelectronic incorporation or surfactant effect. It is, with detailed lineshape analysis and the evidence of PL peak splitting in a magnetic filed, attributed to the electron concentration enhancement induced by Bi flux. The electron concentration in InAs film is evaluated, which is about 5-fold enhanced as Bi/As flux ratio rises up from 0 to 1x10(-3). The temperature dependence of the PL spectrum indicates that the carrier redistribution augments while the carrier-phonon Frohlich scattering weakens in InAs films with high Bi/As flux ratios. These findings reveal a novel Bi effect of electron concentration enhancement, and contribute to the basic knowledge of Bi in III-V semiconductors.
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13. |
- Chen, X, et al.
(author)
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Negative thermal quenching of below-bandgap photoluminescence in InPBi
- 2017
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In: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 110:5
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Journal article (peer-reviewed)abstract
- This paper reports a temperature-dependent (10-280 K) photoluminescence (PL) study of below-bandgap electron-hole recombinations and anomalous negative thermal quenching of PL intensity in InP1- xBix (x = 0.019 and 0.023). Four PL features are well resolved by curve-fitting of the PL spectra, of which the energies exhibit different temperature dependence. The integral intensities of the two high-energy features diminish monotonically as temperature rises up, while those of the two low-energy features decrease below but increase anomalously above 180 K. A phenomenological model is established that the residual electrons in the final state of the PL transition transfer into nonradiative state via thermal hopping, and the thermal hopping produces in parallel holes in the final state and hence enhances the radiative recombination significantly. A reasonable interpretation of the PL processes in InPBi is achieved, and the activation energies of the PL quenching and thermal hopping are deduced. © 2017 Author(s).
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14. |
- Ding, Jiangwei, et al.
(author)
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All Roads Lead to Rome? : Genes Causing Dravet Syndrome and Dravet Syndrome-Like Phenotypes
- 2022
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In: Frontiers in Neurology. - : Frontiers Media S.A.. - 1664-2295. ; 13
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Research review (peer-reviewed)abstract
- Background: Dravet syndrome (DS) is a severe epileptic encephalopathy mainly caused by haploinsufficiency of the gene SCN1A, which encodes the voltage-gated sodium channel NaV1. 1 in the brain. While SCN1A mutations are known to be the primary cause of DS, other genes that may cause DS are poorly understood. Several genes with pathogenic mutations result in DS or DS-like phenotypes, which may require different drug treatment approaches. Therefore, it is urgent for clinicians, especially epilepsy specialists to fully understand these genes involved in DS in addition to SCN1A. Particularly for healthcare providers, a deep understanding of these pathogenic genes is useful in properly selecting and adjusting drugs in a more effective and timely manner.Objective: The purpose of this study was to identify genes other than SCN1A that may also cause DS or DS-like phenotypes. Methods: A comprehensive search of relevant Dravet syndrome and severe myoclonic epilepsy in infancy was performed in PubMed, until December 1, 2021. Two independent authors performed the screening for potentially eligible studies. Disagreements were decided by a third, more professional researcher or by all three. The results reported by each study were narratively summarized.Results: A PubMed search yielded 5,064 items, and other sources search 12 records. A total of 29 studies published between 2009 and 2021 met the inclusion criteria. Regarding the included articles, seven studies on PCDH19, three on SCN2A, two on SCN8A, five on SCN1B, two on GABRA1, three on GABRB3, three on GABRG2, and three on STXBP1 were included. Only one study was recorded for CHD2, CPLX1, HCN1 and KCNA2, respectively. It is worth noting that a few articles reported on more than one epilepsy gene.Conclusion: DS is not only identified in variants of SCN1A, but other genes such as PCDH19, SCN2A, SCN8A, SCN1B, GABRA1, GABRB3, GABRG2, KCNA2, CHD2, CPLX1, HCN1A, STXBP1 can also be involved in DS or DS-like phenotypes. As genetic testing becomes more widely available, more genes associated with DS and DS-like phenotypes may be identified and gene-based diagnosis of subtypes of phenotypes in this spectrum may improve the management of these diseases in the future.
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15. |
- Fa, Wenxin, et al.
(author)
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Associations of Blood Absolute Neutrophil Count and Cytokines With Cognitive Function in Dementia-Free Participants : A Population-Based Cohort Study
- 2023
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In: The journals of gerontology. Series A, Biological sciences and medical sciences. - 1079-5006 .- 1758-535X.
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Journal article (peer-reviewed)abstract
- Background: The relationships of neutrophils and cytokines with cognitive dysfunction are poorly defined. We aimed to investigate the association of peripheral blood absolute neutrophil count (ANC) with cognitive function in older adults and to further explore the mediating role of serum cytokines in this association.Methods: This population-based cohort study included 1 666 dementia-free participants (age ≥60 years) derived from baseline examinations (March–September 2018) of the Multimodal Intervention to Delay Dementia and Disability in Rural China (MIND-China); of these, 1 087 participants completed follow-up examinations in October–December 2019. We used a neuropsychological test battery to assess episodic memory, verbal fluency, attention, and executive function at the baseline and follow-up examinations. We used Mindray BC-6800 automated hematology analyzer to measure ANC and Meso Scale Discovery to measure serum interleukin-6 (IL-6) and eotaxin-3.Results: The linear regression analysis of cross-sectional data at baseline (n = 1 666) suggested that increased ANC was significantly associated with a lower episodic memory z score (β coefficient: −0.149, 95% CI: −0.274 to −0.023) and lower long-delayed free recall z score (−0.216, −0.361 to −0.070). Serum IL-6 and eotaxin-3 could mediate 16.16% to 20.21% and 7.55% to 9.35%, respectively, of these associations. The analysis of longitudinal data (n = 1 087) showed a J-shaped relationship of ANC with decline in episodic memory z score (p for nonlinear = .049), and a U-shaped relationship between ANC and decline in long-delayed free recall z score (p for nonlinear = .043).Conclusions: Increased neutrophils are associated with poor cognitive performance and accelerated decline in episodic memory, and the cross-sectional association is partly mediated by serum cytokines.
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16. |
- Gao, Qingwei, et al.
(author)
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Effect of dimethyl carbonate on the behavior of water confined in carbon nanotube
- 2021
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In: Chinese Journal of Chemical Engineering. - : Elsevier. - 1004-9541 .- 2210-321X. ; 31, s. 177-185
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Journal article (peer-reviewed)abstract
- The dehydration of water by dimethyl carbonate (DMC) is of great significance for its application in electrochemistry and oil industry. With the rapid development of nanomaterial, one-dimensional (e.g. carbon nanotube (CNT)) and two-dimensional (e.g. lamellar graphene) materials have been widely used for molecular sieving. In this work, the molecular behavior of dimethyl carbonate/water mixture confined in CNT with varying diameters was studied based on molecular dynamics simulation. Due to different van der Waals interactions for the components in the mixtures with the solid surface, DMC molecules are preferentially adsorbed on the inner surface of the pore wall and formed an adsorption layer. Comparing with the pure water molecules confined in CNT, the adsorption DMC layer shows notable effect on the local compositions and microstructures of water molecules under nanoconfinement, which may result in different water mobility. Our analysis shows that the surface-induced DMC molecules can destroy the hydrogen bonding network of water molecules and result in an uniform and dispersed distribution of water molecules in the tube. These clear molecular understandings can be useful in material design for membrane separation.
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17. |
- Gao, Qingwei, et al.
(author)
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Molecular insight into wetting behavior of deep eutectic solvent droplets on ionic substrates : A molecular dynamics study
- 2020
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In: Journal of Molecular Liquids. - : Elsevier. - 0167-7322 .- 1873-3166. ; 319
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Journal article (peer-reviewed)abstract
- Wetting behavior of droplets made of choline chloride/urea (1:2), an archetypal deep eutectic solvent mixture, is studied using molecular dynamics simulations. The droplets are placed on a smooth model ionic substrate with positive and negative charges of the same magnitude q (0 e ≤ q ≤ 1.0 e), corresponding to a step-by-step change from a hydrophobic to hydrophilic surface. The molecular microstructure of the droplets and their spatial compositions are systematically studied in details on how they both change while gradually moving from hydrophobic to hydrophilic surface. It is observed that urea initially forms a monolayer on the surface with a planar orientation. This layer slowly shrinks while it becomes laterally more and more constrained. It becomes also molecularly more ordered when the surface becomes hydrophilic, at the same time as the contact angles become larger and larger. The anions (Cl-) are continuously pushed further away from the charged surface. While the contact angle increases and wetting decreases, and urea forms even a secondary stable layer where it changes its orientation and turns to have one of its amines facing up and carbonyl down. The average number of urea-urea H-bonds decreases linearly while the number of ion-pair contacts increases when the urea molecules are separating from the mixture. Our analysis gives a clear molecular understanding of the process and can be useful in many applications from membrane separation to catalysis.
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18. |
- Gao, Qingwei, et al.
(author)
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Physicochemical properties and structure of fluid at nano-/micro-interface : Progress in simulation and experimental study
- 2020
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In: Green Energy & Environment. - : Elsevier. - 2468-0257. ; 5:3, s. 274-285
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Research review (peer-reviewed)abstract
- In modern chemical engineering processes, the involvement of solid/fluid interface is the most important component of process intensification techniques, such as confined membrane separation and catalysis. In the review, we summarized the research progress of the latest theoretical and experimental works to elucidate the contribution of interface to the fluid properties and structures at nano- and micro-scale. We mainly focused on water, alcohol aqueous solution, and ionic liquids, because they are classical systems in interfacial science and/or widely involved in the industrialization process. Surface-induced fluids were observed in all reviewed systems and played a critical role in physicochemical properties and structures of outside fluid. It can even be regarded as a new interface, when the adsorption layer has a strong interaction with the solid surface. Finally, we proposed a perspective on scientific challenges in the modern chemical engineering processes and outlined future prospects.
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19. |
- Gao, Qingwei, et al.
(author)
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Preliminary study on mechanism of confined mass transfer and separation : "secondary confinement" effect of interfacial adsorption layer [限域传质分离机制初探:界面吸附层的"二次限域"效应]
- 2020
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In: Huagong Xuebao/CIESC Journal. - : Materials China. - 0438-1157. ; 71:10, s. 4688-4695
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Journal article (peer-reviewed)abstract
- The confined mass transfer separation membrane is mainly for the high-precision separation process at the molecular/ion level, which is of great significance to solve the application needs of CO2 separation, azeotrope separation, lithium extraction from salt lake, desalination of seawater and so on. However, at present, the research of the confined mass transfer mechanism of this kind of membrane is lagging behind, and the theoretical models of confined mass transfer are lacking, which can no longer meet the needs of the rapid development of materials and chemical engineering. From the perspective of meso-science, the abnormal phenomenon of high flux and high selectivity of the confined mass transfer separation membrane is considered, that is, breaking through the trade-off effect, which is governed by compromise-in-competition between the selectivity mechanism and the flux mechanism. It is found that the fluid molecules will preferentially adsorb at the interface and form a stable adsorption layer. Based on this, the hypothesis of "secondary confinement" is put forward, that is, the surface induced new solid-like interface will have confinement effect on the intermediate fluid again. By comparing the pore size and the secondary confined size of the confined mass transfer separation membrane, the selective mechanism of the secondary confinement is further confirmed, and the quantitative prediction of the membrane flux and selectivity is preliminarily explored by combining the selective mechanism and the flux model, which may provide a theoretical basis for the precise construction of the limited area mass transfer membrane. © 2020, Chemical Industry Press Co., Ltd. All right reserved.
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20. |
- Guo, Hao, et al.
(author)
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A humanized monoclonal antibody targeting secreted anterior gradient 2 effectively inhibits the xenograft tumor growth.
- 2016
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In: Biochemical and Biophysical Research Communications - BBRC. - : Elsevier BV. - 0006-291X .- 1090-2104. ; 475:1, s. 57-63
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Journal article (peer-reviewed)abstract
- Anterior Gradient 2 (AGR2) is a potential anti-tumor target and we previously reported a murine antibody 18A4 with specific binding to AGR2. However, humanization is a must to overcome immunogenicity before considering for clinical use and optimized vectors for mammalian expression are also necessary for following industrialized manufacture. Here, we describe an anti-tumor humanized antibody blocking secreted AGR2 activity. We employed the CDR grafting technique and deimmunization analysis to construct humanized antibody variants of 18A4, and 18A4Hu I was selected as the best humanization candidate, characterized by physical and chemical property comparison. Mouse xenograft study showed that 18A4Hu I could effectively inhibit the xenograft tumor growth, antibody blocking epitope analysis using AGR2 mutants indicated that the inhibition activity of 18A4Hu I is exerted probably through blocking the AGR2 functions which rely on the amino acid sites of E60-H76 and A86-E153. What's more, in this report, we also describe a pHAb-FAST vector system which is specifically designed for humanized antibody mammalian expression vector fast construction. With pHAb-FAST system, expression vector of 18A4Hu I could be quickly constructed only through twice overlapping PCR reactions. To our knowledge, AGR2-targeted 18A4Hu I is a promising humanized anti-tumor drug candidate, and pHAb-FAST system is a useful optimized mammalian expression vector construction tool. Our findings are supposed to accelerate the development of antibody-based cancer therapy.
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21. |
- Ji, Xiaoyan, et al.
(author)
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A SAFT Equation of State for the H2S-CO2-H2O-NaCl system and applications for CO2 - H2S transportation and geological storage
- 2013
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In: Energy Procedia. - : Elsevier BV. - 1876-6102. ; 37, s. 3780-3791
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Journal article (peer-reviewed)abstract
- When H2S is co-injected with CO2, we need to know thermodynamic properties and phase equilibria for the CO2-H2S- H2O-NaCl system in order to evaluate the sequestration capacity, optimal transportation and injection conditions, potential for pipeline corrosion, and increased risk of storage and leakage. Here, we summarize the results of the phase equilibrium and densities for CO2-sequestration related systems from a thermodynamic model that is based on statistical associating fluid theory equation of state. The proposed thermodynamic model can be used to represent equilibrium compositions in both phases (H2O-rich/aqueous phases and gas-rich/nonaqueous phases) and the density at equilibrium or in the one phase region. The effect of H2S on the properties of CO2 streams and on the CO2 solubility and the corresponding aqueous solution density can be predicted to provide a knowledge base for both transportation and geological storage. In addition, as other ions such as Ca, Mg, K and SO4 have been taken into account in the model, the properties for brine instead of aqueous NaCl solutions can also be predicted. The equation of state can be incorporated into reservoir simulators to model the separation of phases in multi-phase flow and fluid reactions with reservoir rocks
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22. |
- Ji, Xiaoyan, et al.
(author)
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A SAFT equation of state for the quaternary H2S-CO2-H2O-NaCl system
- 2012
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In: Geochimica et Cosmochimica Acta. - : Elsevier BV. - 0016-7037 .- 1872-9533. ; 91, s. 40-59
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Journal article (peer-reviewed)abstract
- Phase equilibria and thermodynamic properties of the quaternary H2S-CO2-H2O-NaCl system were studied using a statistical associating fluid theory (SAFT)-based equation of state (EOS) at temperatures from 0 to 200 °C (373.15 to 473.15 K), pressures up to 600 bar (60 MPa) and concentration of NaCl up to 6 mol/kgH2O. The understanding of the physical-chemical properties of this system is critical for predicting the consequences of co-injection of CO2 and H2S into geological formations (geological carbon sequestration) as an option for mitigating the global warming trend. Equation of state parameters were generated from regression of available and reliable experimental data and incorporation of existing parameters for some subsystems. Densities were predicted and compared with available experimental results. Using the EOS developed in this study, we predicted equilibrium composition in both liquid and vapor phases, fugacity coefficients of components, the equilibrium pressures at a given composition of the H2O-rich phase in electrolyte solutions with NaCl varying from 0 to 4 mol/kgH2O, and the aqueous solution densities. These predicted values are tabulated and available as supplementary data in the electronic version online. These predictions provide information and guidance for future experiments regarding the thermodynamic properties and phase behaviors in the H2S-CO2-H2O-NaCl system
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23. |
- Ji, Xiaoyan, et al.
(author)
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CO2 Storage in Deep Saline Aquifers
- 2015
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In: Novel Materials for Carbon Dioxide Mitigation Technology. - : Elsevier. - 9780444632593 ; , s. 299-332
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Book chapter (peer-reviewed)abstract
- CO2 geological storage is a promising means of mitigating CO2 emissions, and deep saline aquifers appear to hold the largest potential storage capacity. Large-scale injection of CO2 into saline aquifers will induce a variety of coupled physical and chemical processes including multiphase fluid flow, solute transport, and chemical reactions between fluids and formation minerals. Thermodynamic and dynamic investigations are needed to study the sequestration capacity, CO2 leakage, and environmental impacts. Meanwhile, co-injection of CO2 with impurities may substantially reduce the capture and sequestration costs, but it is necessary to investigate the effect of impurities on both thermodynamic and dynamic models. In this chapter, CO2 capture and storage is briefly introduced. The development of the thermodynamic model representing phase equilibrium and thermodynamic properties for CO2-storage-related systems is reviewed, and the model based on Statistical Associating Fluid Theory (SAFT) is introduced in detail. Thermodynamic properties of density and equilibrium composition for CO2-storage-related systems are presented with an SAFT-based model, and the effect of impurities is investigated. Future work to extent the SAFT-based model to represent viscosity, interfacial properties, as well as the fluid behavior on confined pores is discussed. It is expected that the model can be further incorporated into process models to provide a reliable long-term prediction pertaining to geological carbon sequestration, such as sequestration capacity, CO2 leakage, environmental impacts, and so forth.
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24. |
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25. |
- Ji, Xiaoyan, et al.
(author)
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Modeling of phase equilibria in the H2S-H2O system with the statistical associating fluid theory
- 2010
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In: Energy & Fuels. - : American Chemical Society (ACS). - 0887-0624 .- 1520-5029. ; 24:11, s. 6208-6213
-
Journal article (peer-reviewed)abstract
- The phase equilibria of the binary system of H2S-H2O are represented using the statistical associating fluid theory. H2S is modeled as a molecule with four association sites, i.e., two sites of type S and two sites of type H, and sites of the same type do not associate with each other. The parameters of H2S are fitted to its vapor pressure and saturated liquid density. Cross-association between the site H in H2S and the site O in H2O is allowed, and two temperature-dependent parameters are used to describe this cross-association. A temperature-dependent binary interaction parameter is used to correct the cross-dispersive energy for this binary system. Cross-parameters are fitted to mole fractions in both H2S-rich/vapor and H2O-rich phases. The model is found to represent well the phase equilibria of the H2S-H2O system from 273 to 630 K and at pressures up to 200 bar
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26. |
- Ji, Xiaoyan, et al.
(author)
-
Modelling of phase equilibria in the H2S-H2O system with statistical associating fluid theory
- 2010
-
In: PRES 2010. - Milano : AIDIC Servizi S.r.l.. - 9788895608051
-
Conference paper (peer-reviewed)abstract
- Sequestration of greenhouse gases into geological brine formation is one of the promising options for the reduction of greenhouse gases. Co-injection of both CO 2 and H 2S from flue gas may reduce the cost of carbon sequestration. The phase equilibrium of H 2S-H 2O was investigated with SAFT EOS. H 2S was modeled as a molecule with four association sites. For the H 2S-H 2O system, cross association between the site H in H 2S and the site O in H 2O was allowed, and a temperature-dependent binary interaction parameter was used to adjust the cross dispersive energy between the segments of H 2S and H 2O. The parameters of H 2S were obtained from the fitting of saturated vapor pressure and liquid density of H 2S. The model could be used to represent the phase equilibrium for H 2S-H 2O system from 273 to 630 K and ≤ 200 bar
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27. |
- Ji, Xiaoyan, et al.
(author)
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Predicting possible effects of H2S impurity on CO2 transportation and geological storage
- 2013
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In: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 47:1, s. 55-62
-
Journal article (peer-reviewed)abstract
- For CO2 geological storage, permitting impurities, such as H2S, in CO2 streams can lead to a great potential for capital and energy savings for CO2 capture and separation,but it also increases costs and risk management for transportation and storage. To evaluate the cost−benefits, using a recently developed model (Ji, X.; Zhu, C. Geochim. Cosmochim. Acta 2012, 91, 40−59), this study predicts phase equilibria and thermodynamic properties of the system H2S−CO2−H2O−NaCl under transportation and storage conditions and discusses potential effects of H2S on transportation and storage. The prediction shows that inclusion of H2S in CO2 streams may lead to two-phase flow. For H2S−CO2 mixtures, at a given temperature, the bubble and dew pressures decrease with increasing H2S content, while the mass density increases at low pressures and decreases at high pressures. For the CO2−H2S−H2O system, the total gas solubility increases while the mass density of the aqueous solution with dissolved gas decreases. For the CO2−H2S−H2O−NaCl system, at a given temperature, pressure and NaCl concentration, the solubility of the gas mixture in aqueous phase increases with increasing H2S content and then decreases, while the mass density of aqueous solution decreases and may be lower than the mass density of the solution without gas dissolution.
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28. |
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29. |
- Leng, Yan, et al.
(author)
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Alterations of Elastic Property of Spastic Muscle With Its Joint Resistance Evaluated From Shear Wave Elastography and Biomechanical Model
- 2019
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In: Frontiers in Neurology. - : Frontiers Media S.A.. - 1664-2295. ; 10
-
Journal article (peer-reviewed)abstract
- This study aims to quantify passive muscle stiffness of spastic wrist flexors in stroke survivors using shear wave elastography (SWE) and to correlate with neural and non-neural contributors estimated from a biomechanical model to hyper-resistance measured during passive wrist extension. Fifteen hemiplegic individuals after stroke with Modified Ashworth Scale (MAS) score larger than one were recruited. SWE were used to measure Young's modulus of flexor carpi radialis muscle with joint from 0 degrees (at rest) to 50 degrees flexion (passive stretch condition), with 10 degrees interval. The neural (NC) and non-neural components i.e., elasticity component (EC) and viscosity component (VC) of the wrist joint were analyzed from a motorized mechanical device NeuroFlexor (R) (NF). Combining with a validated biomechanical model, the neural reflex and muscle stiffness contribution to the increased resistance can be estimated. MAS and Fugl-Meyer upper limb score were also measured to evaluate the spasticity and motor function of paretic upper limb. Young's modulus was significantly higher in the paretic side of flexor carpi radialis than that of the non-paretic side (p < 0.001) and it increased significantly from 0 degrees to 50 degrees of the paretic side (p < 0.001). NC, EC, and VC on the paretic side were higher than the non-paretic side (p < 0.05). There was moderate significant positive correlation between the Young's Modulus and EC (r = 0.565, p = 0.028) and VC (r = 0.645, p = 0.009) of the paretic forearm flexor muscle. Fugl-Meyer of the paretic forearm flexor has a moderate significant negative correlation with NC (r = -0.578, p = 0.024). No significant correlation between MAS and shear elastic modulus or NF components was observed. This study demonstrated the feasibility of combining SWE and NF as a non-invasive approach to assess spasticity of paretic muscle and joint in stroke clinics. The neural and non-neural components analysis as well as correlation findings of muscle stiffness of SWE might provide understanding of mechanism behind the neuromuscular alterations in stroke survivors and facilitate the design of suitable intervention for them.
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30. |
- Li, Jiajia, et al.
(author)
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Gravity field induced composite solid electrolytes enabling enhanced Li+ transport kinetics of lithium metal battery
- 2024
-
In: Chemical Engineering Journal. - : Elsevier. - 1385-8947 .- 1873-3212. ; 484
-
Journal article (peer-reviewed)abstract
- Multilayer composite solid electrolytes (CSEs) exhibit many advantages over uniform monolayer CSEs but are hindered by high interlayer resistance and complex preparation methods. Herein, for the first time, a natural sedimentation strategy was developed to construct concentration gradient CSEs (GCSEs) for lithium-metal batteries (LMBs). This method utilizes intrinsic gravity and photopolymerization to achieve multiple functions in the monolayer, avoiding additional interlayer resistance and reducing preparation time. Owning to the concentration gradient structure, the Li+ transport on the PolyIL-rich side relies on the weak solvation of Li+ with EMIMTFSI, while the Li+ transport on the LLZTO-rich side follows the 'vehicular diffusion' mechanism with the aid of TFSI−, improving the Li+ transport and enhances the Li+ transference number, leading to the high stability to 2300 h for the Li//Li cell and stable operation at 4.3 V with 89.6 % capacity retention after 100 cycles for the assembled LMB. Moreover, compared with the monolayer uniform hybrid CSEs, the gradient structure alleviates uncoordinated thermal expansion between LLZTO and PolyIL, avoiding stress increase during cycling and battery capacity fade. This gradient strategy mitigates high interlayer resistance and offers a universal path to address the sluggish Li+ transportation in multilayer CSEs and improves compatibility between the electrolyte and electrodes in fabricating solid-state batteries.
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31. |
- Li, Xuping, et al.
(author)
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A three-dimensional ratiometric sensing strategy on unimolecular fluorescence-thermally activated delayed fluorescence dual emission
- 2019
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In: Nature Communications. - : NATURE PUBLISHING GROUP. - 2041-1723. ; 10
-
Journal article (peer-reviewed)abstract
- Visualized sensing through fluorescence signals is a powerful method for chemical and physical detection. However, the utilization of fluorescent molecular probes still suffers from lack of precise signal self-calibration in practical use. Here we show that fluorescence and thermally activated delayed fluorescence can be simultaneously produced at the single-molecular level. The thermally activated delayed fluorescence serves as a sensing signal with its wavelength and lifetime both altered correlating to polarity, whereas the fluorescence always remains unchanged as an internal reference. Upon the establishment of a three-dimensional working curve upon the ratiometric wavelength and photoluminescence lifetime vs. polarity, disturbance factors during a relevant sensing process can be largely minimized by such a multiple self-calibration. This strategy was further applied into a precise detection of the microenvironmental polarity variation in complex phospholipid systems, towards providing new insights for convenient and accurate diagnosis of membrane lesions.
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32. |
- Liang, Xiaoyan, et al.
(author)
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Exosomal miR-532-5p induced by long-term exercise rescues blood–brain barrier function in 5XFAD mice via downregulation of EPHA4
- 2023
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In: Aging Cell. - : Wiley. - 1474-9718 .- 1474-9726. ; 22:1
-
Journal article (peer-reviewed)abstract
- The breakdown of the blood–brain barrier, which develops early in Alzheimer's disease (AD), contributes to cognitive impairment. Exercise not only reduces the risk factors for AD but also confers direct protection against cognitive decline. However, the exact molecular mechanisms remain elusive, particularly whether exercise can liberate the function of the blood–brain barrier. Here, we demonstrate that long-term exercise promotes the clearance of brain amyloid-β by improving the function of the blood–brain barrier in 5XFAD mice. Significantly, treating primary brain pericytes or endothelial cells with exosomes isolated from the brain of exercised 5XFAD mice improves cell proliferation and upregulates PDGFRβ, ZO-1, and claudin-5. Moreover, exosomes isolated from exercised mice exhibit significant changes in miR-532-5p. Administration or transfection of miR-532-5p to sedentary mice or primary brain pericytes and endothelial cells reproduces the improvement of blood–brain barrier function. Exosomal miR-532-5p targets EPHA4, and accordingly, expression of EphA4 is decreased in exercised mice and miR-532-5p overexpressed mice. A specific siRNA targeting EPHA4 recapitulates the effects on blood–brain barrier-associated cells observed in exercised 5XFAD mice. Overall, our findings suggest that exosomes released by the brain contain a specific miRNA that is altered by exercise and has an impact on blood–brain barrier function in AD.
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33. |
- Liu, Xiaomei, et al.
(author)
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Cognitive Benefit of a Multidomain Intervention for Older Adults at Risk of Cognitive Decline : A Cluster- Randomized Controlled Trial
- 2023
-
In: The American journal of geriatric psychiatry. - : Elsevier BV. - 1064-7481 .- 1545-7214. ; 31:3, s. 197-209
-
Journal article (peer-reviewed)abstract
- Objective: We sought to assess cognitive benefits of a community-based multi -domain intervention for improving cognition among older adults at risk of cog-nitive decline (COMBAT). Design: A two-armed cluster-randomized controlled trial. Setting and Participants: Community-dwelling older adults aged 60 years or older and were at risk of cognitive decline (n = 209). Intervention: In this 9-month intervention study, 10 community hospitals in Beijing, China, were randomized (1:1) to receive either a multidomain inter-vention of meditation, cognitive training, exercise, and nutrition counseling or usual care. The intervention was delivered with weekly 1-hour group training sessions and weekly home homework. Measurements: Primary outcome was change in cognition as measured by a composite Z score of seven cognitive tests. Secondary outcomes included subjective cognitive abilities, positive and nega-tive affective experiences, physical activity, and dietary habits. Assessments were administered at baseline, end of the intervention, and 1 year after com-pleting the intervention (1-year follow-up). Results: Immediately after the intervention, the intervention group showed significant enhancement in cogni-tive performance (p = 0.026). The between-group difference in the Z score of change of cognition was 0.20 (95% CI: 0.053, 0.35), with a Hedges' g of 0.40 (95% CI: 0.29, 0.50). However, this cognitive benefit was not significant at
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34. |
- Lu, Xiaohua, et al.
(author)
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Thermodynamic mechanism of complex fluids-solids interfacial interaction
- 2019
-
In: Huagong Xuebao/CIESC Journal. - : Materials China. - 0438-1157. ; 70:10, s. 3677-3689
-
Research review (peer-reviewed)abstract
- Interfacial transfer at mesoscale is a common issue for all the multi-phase chemical processes, and the related study remains as a scientific challenge due to the complexities. Investigating the interfacial interactions at mesoscale to find out the regulation strategies is the key to realize process-intensification of mass-transfer and reaction for the advanced chemical industries. To accurately describe the behavior of fluids at the interface, a new molecular thermodynamic model that can describe the complex fluid-solid interface interaction. When the molecular thermodynamic modeling method is extended to the nano-micro interfacial transfer needs to be developed, calling for the coordination of advanced experiments at nano-micro scale and molecular with molocular thermodynamic modelling. Atomic force microscopy (AFM), which possess the sensitivity down to nanoscale, can directly obtain the interfacial interaction at nano-micro scale. The quantification of AFM-measured forces can be used to construct the coarse-grained molecular model and describe complex interfacial interaction. Then, the coarse-grained molecular model can reveal the molecular thermodynamic mechanism of nano- and micro- interface transfer, realizing quantitative prediction.
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35. |
- Pan, Wenwu, et al.
(author)
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Photoluminescence of InGaAs/GaAsBi/InGaAs type-II quantum wells grown by gas source molecular beam epitaxy
- 2017
-
In: Semiconductor Science and Technology. - : IOP Publishing. - 1361-6641 .- 0268-1242. ; 32:1
-
Journal article (peer-reviewed)abstract
- InxGa1-xAs/GaAs1-yBiy/InxGa1-xAs (0.20 ≤x ≤0.22, 0.035 ≤y ≤0.045) quantum wells (QWs) were grown on GaAs substrates by gas source molecular beam epitaxy for realizing the type-II band edge line-up. Both type-I and type-II transitions were observed in the Bi containing W QWs and the photoluminescence intensity was enhanced in the sample with a high Bi content, which is mainly due to the improvement of carrier confinement. The 8 band k • p model was used to analyze the electronic properties in the QWs and the calculated transition energies fit well with the experiment results. Our study shows that the proposed type-II QW is a promising candidate for realizing GaAs-based near infrared light emitting devices near 1.3 μm
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36. |
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37. |
- Sun, Hao, et al.
(author)
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Engineering Tunable Ratiometric Dual Emission in Single Emitter-based Amorphous Systems
- 2024
-
In: Angewandte Chemie International Edition. - : WILEY-V C H VERLAG GMBH. - 1433-7851 .- 1521-3773.
-
Journal article (peer-reviewed)abstract
- Molecular emitters with multi-emissive properties are in high demand in numerous fields, while these properties basically depend on specific molecular conformation and packing. For amorphous systems, special molecular arrangement is unnecessary, but it remains challenging to achieve such luminescent behaviors. Herein, we present a general strategy that takes advantage of molecular rigidity and S1-T1 energy gap balance for emitter design, which enables fluorescence-phosphorescence dual-emission properties in various solid forms, whether crystalline or amorphous. Subsequently, the amorphism of the emitters based polymethyl methacrylate films endowed an in situ regulation of the dual-emissive characteristics. With the ratiometric regulation of phosphorescence by external stimuli and stable fluorescence as internal reference, highly controllable luminescent color tuning (yellow to blue including white emission) was achieved. There properties together with a persistent luminous behavior is of benefit for an irreplaceable set of optical information combination, featuring an ultrahigh-security anti-counterfeiting ability. Our research introduces a concept of eliminating the crystal-form and molecular-conformational dependence of complex luminescent properties through emitter molecular design. This has profound implications for the development of functional materials. A molecular structural strategy enabling single emitter based dual-emission properties in various solid forms is presented. The developed amorphous films endow in situ regulation of the dual-emissive characteristics to show highly controllable multiple luminescent color tuning (yellow to blue including white emission), which benefits to the construction of an irreplaceable set of optical information combination.image
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38. |
- Tian, Na, et al.
(author)
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Triglyceride-glucose index, Alzheimer's disease plasma biomarkers, and dementia in older adults : The MIND-China study
- 2023
-
In: Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring. - 2352-8729. ; 15:2
-
Journal article (peer-reviewed)abstract
- Introduction: Population-based studies have rarely explored the associations of the triglyceride–glucose (TyG) index, a surrogate marker of insulin resistance, with dementia and plasma biomarkers for amyloid beta (Aβ) and neurodegeneration.Methods: This population-based study included 5199 participants (age ≥ 65 years); of these, plasma Aβ, total tau, and neurofilament light chain (NfL) were measured in 1287 persons. Dementia and subtypes were diagnosed following the international criteria. TyG index was calculated as ln(fasting triglyceride(mg/dL) × fasting glucose[mg/dL]/2). Data were analyzed using logistic and general linear regression models.Results: Dementia, Alzheimer's disease (AD), and vascular dementia (VaD) were diagnosed in 301, 195, and 95 individuals, respectively. A high TyG index was significantly associated with increased likelihoods of dementia and AD; the significant association with dementia remained among participants without cardiovascular disease or diabetes. In the biomarker subsample, a high TyG index was correlated with elevated plasma Aβ, but not with total tau or NfL.Discussion: High TyG index is associated with dementia, possibly via Aβ pathology.
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39. |
- Wang, Zechao, et al.
(author)
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Atomic scale imaging of magnetic circular dichroism by achromatic electron microscopy
- 2018
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In: Nature Materials. - : NATURE PUBLISHING GROUP. - 1476-1122 .- 1476-4660. ; 17:3, s. 221-225
-
Journal article (peer-reviewed)abstract
- In order to obtain a fundamental understanding of the interplay between charge, spin, orbital and lattice degrees of freedom in magnetic materials and to predict and control their physical properties1-3, experimental techniques are required that are capable of accessing local magnetic information with atomic-scale spatial resolution. Here, we show that a combination of electron energy-loss magnetic chiral dichroism(4) and chromatic-aberration-corrected transmission electron microscopy, which reduces the focal spread of inelastically scattered electrons by orders of magnitude when compared with the use of spherical aberration correction alone, can achieve atomic-scale imaging of magnetic circular dichroism and provide element-selective orbital and spin magnetic moments atomic plane by atomic plane. This unique capability, which we demonstrate for Sr2FeMoO6, opens the door to local atomic-level studies of spin configurations in a multitude of materials that exhibit different types of magnetic coupling, thereby contributing to a detailed understanding of the physical origins of magnetic properties of materials at the highest spatial resolution.
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40. |
- Wu, Nanhua, et al.
(author)
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Mesoscience in Supported Nano-metal Catalysts based on Molecular Thermodynamic Modeling : A Mini Review and Perspective
- 2021
-
In: Chemical Engineering Science. - : Elsevier. - 0009-2509 .- 1873-4405. ; 229
-
Research review (peer-reviewed)abstract
- Supported nano-metal catalysts are widely used in industrial processes. There is a trade-off between the activity and stability from mesoscale, which can be effectively tackled with the principle of compromise in competition (mechanisms A and B). To apply mesoscience methodology in this specific area, this work summarized research progress, where direct H2O2 synthesis was chosen as a typical case to identify and represent mechanism A (activity) and mechanism B (stability). It was found that mechanism A has been widely studied, while mechanism B still cannot reflect explosion. Subsequently, reaction heat and fusion enthalpy were proposed to represent mechanism B in this work, and the molecular thermodynamic model was identified as an effective tool for the study. A corresponding framework for mechanism B was constructed and the progress in developing the model for this particular purpose was provided. Finally, perspectives were discussed based on the linear non-equilibrium thermodynamics.
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41. |
- Wu, Xiuchen, et al.
(author)
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Exposures to temperature beyond threshold disproportionately reduce vegetation growth in the northern hemisphere
- 2019
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In: National Science Review. - : Oxford University Press (OUP). - 2095-5138 .- 2053-714X. ; 6:4, s. 786-795
-
Journal article (peer-reviewed)abstract
- In recent decades, terrestrial vegetation in the northern hemisphere (NH) has been exposed to warming and more extremely high temperatures. However, the consequences of these changes for terrestrial vegetation growth remain poorly quantified and understood. By examining a satellite-based vegetation index, tree-ring measurements and land-surface model simulations, we discovered a consistent convex pattern in the responses of vegetation growth to temperature exposure (TE) for forest, shrub and grass in both the temperate (30°−50° N) and boreal (50°−70° N) NH during the period of 1982−2012. The response of vegetation growth to TE for the three vegetation types in both the temperate and boreal NH increased convergently with increasing temperature, until vegetation type-dependent temperature thresholds were reached. A TE beyond these temperature thresholds resulted in disproportionately weak positive or even strong negative responses. Vegetation growth in the boreal NH was more vulnerable to extremely high-temperature events than vegetation growth in the temporal NH. The non-linear responses discovered here provide new insights into the dynamics of northern terrestrial ecosystems in a warmer world.
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42. |
- Zhang, Guanru, et al.
(author)
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CO2 Plume Migration and Fate at Sleipner, Norway : Calibration of Numerical Models, Uncertainty Analysis, and Reactive Transport Modelling of CO2 Trapping to 10,000 Years
- 2017
-
In: Energy Procedia. - : Elsevier. - 1876-6102. ; 114, s. 2880-2895
-
Journal article (peer-reviewed)abstract
- The Sleipner Project in Norway is the world's first industrial-scale geological carbon dioxide storage project. Time-lapse seismic monitoring data have been collected, tracing CO2 plume development from 1996 to 2010. Therefore, the Sleipner Project provides a somewhat unique opportunity to simulate the dynamics of CO2 in a real geological system. The purpose of this study is to simulate CO2 plume migration dynamics and assess the impact of uncertain factors on short and long term migration and fate of CO2 for the uppermost layer (Layer 9) of the Utsira Sand.First, we applied a multi-phase compositional simulator to the Sleipner Benchmark model for Layer 9 and calibrated our model against the time-lapsed seismic monitoring data at the site from 1999 to 2008. By adjusting lateral permeability anisotropy, CH4 in the CO2 stream, and reservoir temperature, approximate match with the observed plume was achieved. Model-predicted gas saturation, thickness of the CO2 accumulation, and CO2 solubility in brine (none of them used as calibration metrics) were all comparable with interpretations of the seismic data in the literature.Second, hundreds of simulations of parameter sensitivity (pressure, temperature, feeders, spill rates, relative permeability curves, and CH4 content) were conducted for the plume migration, based on the calibrated model. The results showed that simulated plume extents are sensitive to permeability anisotropy, temperature, and CH4 content, but not sensitive to the other parameters. However, adjusting a single parameter within the reported range of values in the literature would not reproduce the north-south trending CO2 plume; it took a combination of permeability, CH4, and temperature adjustments to match simulated CO2 plume with seismic monitoring data. Although there is a range of uncertain parameters, the predicted fate of CO2 fell within a narrow band, ∼ 93±2% structural trapping and ∼ 7±2% solubility trapping. The calibrated model is not unique. Many combinations of permeability anisotropy, temperature, and CH4 would produce similar matches. Other possibilities that would have improved the development of an N–S elongated CO2 plume, such as a slight tilting of the surface of Utsira top to the south, were not experimented in this study, but are worthy of exploration for future studies.Finally, we used coupled reactive mass transport model to investigate the effects of rate laws and regional groundwater flow on long-term CO2 fate in Layer 9. The mineral composition and brine chemistry for the Utsira sand were adopted from the literature, and we modelled 100 year injection and continued water-rock interaction to 10,000 years. The results indicated that: (1) The predicted fraction of CO2 mineral trapping when using the linear rate law for feldspar dissolution is twice as much as when using the non-linear rate law. (2) Mineral trapping is more significant when regional groundwater flow is taken into consideration. Under the influence of regional groundwater flow, the replenishment of fresh brine from upstream continuously dissolves CO2 at the tail of CO2 plume, generating a larger acidified area where mineral trapping takes place. In a Sleipner like aquifer, the upstream replenishment of groundwater results in ∼ 22% mineral trapping at year 10,000, compared to the ∼ 4% when the effects of regional groundwater are ignored.
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43. |
- Zhang, Man, et al.
(author)
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Highly Efficient Room-Temperature Light-Induced Synthesis of Polymer Dots: A Programming Control Paradigm of Polymer Nanostructurization from Single-Component Precursor
- 2023
-
In: Journal of the American Chemical Society. - : AMER CHEMICAL SOC. - 0002-7863 .- 1520-5126. ; 145:45, s. 24657-24668
-
Journal article (peer-reviewed)abstract
- Polymer dots (PDs) have raised considerable research interest due to their advantages of designable nanostructures, high biocompatibility, versatile photoluminescent properties, and recyclability as nanophase. However, there remains a lack of in situ, real-time, and noncontact methods for synthesizing PDs. Here we report a rational strategy to synthesize PDs through a well-designed single-component precursor (an asymmetrical donor-acceptor-donor molecular structure) by photoirradiation at ambient temperature. In contrast to thermal processes that normally lack atomic economy, our method is mild and successive, based on an aggregation-promoted sulfonimidization triggered by photoinduced delocalized intrinsic radical cations for polymerization, followed by photooxidation for termination with structural shaping to form PDs. This synthetic approach excludes any external additives, rendering a conversion rate of the precursor exceeding 99%. The prepared PDs, as a single entity, can realize the integration of nanocore luminescence and precursor-transferred luminescence, showing 41.5% of the total absolute luminescence quantum efficiency, which is higher than most reported PD cases. Based on these photoluminescent properties, together with the superior biocompatibility, a unique membrane microenvironmental biodetection could be exemplified. This strategy with programming control of the single precursor can serve as a significant step toward polymer nanomanufacturing with remote control, high-efficiency, precision, and real-time operability.
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44. |
- Zhang, Yingying, et al.
(author)
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Energy Consumption Analysis for CO2 Separation from Gas Mixtures with Liquid Absorbents
- 2014
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In: Energy Procedia. - : Elsevier BV. - 1876-6102. ; 61, s. 2695-2698
-
Journal article (peer-reviewed)abstract
- CO2 separation is an energy intensive process, and it plays an important role in both energy saving and CO2 capture and storage (CCS) to deal with global-warming. CO2 can be from different sources in a wide temperature, pressure and concentrations range. Meanwhile, new liquid absorbents are under-development to cost-effectively separate CO2 from gas mixtures. All this makes it crucial to analyze the energy consumption for CO2 separation from different streams and with different absorbents. In this work, the theoretical energy consumption of CO2 separation from flue gas (CO2/N2), lime kiln gas (CO2/N2), biogas (CO2/CH4) and bio-syngas (CO2/H2/CO) was calculated. The results show that the energy consumption of CO2 separation from flue gas is the highest and that from biogas is the lowest. If the CO2 captured from flue gases was substituted by that from biogases, the energy saving would be equivalent to 28.13 million ton standard coal globally. The energy consumption of CO2 separation from biogas using traditional absorbent of 30%MEA and new developed ionic liquids (ILs) was further studied, in which 1-ethyl-3-methy- limidazolium bis[(trifluoromethyl)sulfonyl]imide ([Emim][NTf2]), 1-butyl-3-methylimida- zolium tetrafluoroborate ([Bmim][BF4]), 1-hexyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl] imide ([Hmim][Tf2N]) and 1-butyl-1-methylpyrrolidinium bis[(trifluoromethyl)sulfonyl]imide ([Bmpy][Tf2N]) were screened from 75 ILs. The energy consumptions of CO2 separation using ILs are lower than those of 30%MEA and that of [Bmim][BF4] is the lowest in the four screened ILs. With a very low vapor pressure and high CO2 solubility, it's promising to use ILs as absorbents for CO2 separation.
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45. |
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46. |
- Zhu, Chen, et al.
(author)
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Benchmark modeling of the Sleipner CO2 plume : Calibration to seismic data for the uppermost layer and model sensitivity analysis
- 2015
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In: International Journal of Greenhouse Gas Control. - : Elsevier BV. - 1750-5836 .- 1878-0148. ; 43, s. 233-246
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Journal article (peer-reviewed)abstract
- An important question for the Carbon Capture, Storage, and Utility program is “can we adequately predict the CO2 plume migration?” The Sleipner project in the Norwegian North Sea provides more time-lapse seismic monitoring data than any other sites for tracking CO2 plume development, but significant uncertainties still exist for some reservoir parameters. In order to simulate CO2 plume migration and assess model uncertainties, we applied two multi-phase compositional simulators to the Sleipner Benchmark model for the uppermost layer (Layer 9) of the Utsira Sand and calibrated our model against the time-lapsed seismic monitoring data at the site from 1999 to 2010. Approximate match with the observed plume was achieved by introducing lateral permeability anisotropy, CH4 in the CO2 stream, and adjusting reservoir temperatures. Model-predicted gas saturation, thickness of the CO2 accumulation, and CO2 solubility in brine – none of them used as calibration metrics – were all comparable with interpretations of the seismic data in the literature.Hundreds of simulations of parameter sensitivity (pressure, temperature, feeders, spill rates, relative permeability curves, and CH4) showed that simulated plume extents are sensitive to permeability anisotropy, temperature, and CH4 but not sensitive to the other analyzed parameters. However, adjusting a single parameter within the reported range of values would not reproduce the north–south trending CO2 plume. It took a combination of permeability, CH4, and temperature adjustments to match simulated CO2 plume with seismic monitoring data. On the other hand, even with a range of uncertain modeling parameters, the predicted fate of CO2 fell within a narrow band, ∼93 ± 2% structural/hydrodynamic trapping and ∼7 ± 2% solubility trapping. The calibrated model is not unique. Other possibilities for reproducing the elongated plume such as a slight tilting of the caprock surface to the south and subtle geological features in the Layer 9 were not experimented with in this study, but are worthy of exploration for future studies. While it appears that we were able to reproduce the north–south elongated CO2 plume, which is a modest improvement over previous models, the adjustments of parameters need to be verified with new observations.
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47. |
- Zhu, Changlian, 1964, et al.
(author)
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Erythropoietin improved neurologic outcomes in newborns with hypoxic-ischemic encephalopathy.
- 2009
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In: Pediatrics. - : American Academy of Pediatrics (AAP). - 1098-4275 .- 0031-4005. ; 124:2
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Journal article (peer-reviewed)abstract
- OBJECTIVE: The purpose of this study was to evaluate the efficacy and safety of erythropoietin in neonatal hypoxic-ischemic encephalopathy (HIE), by using a randomized, prospective study design. METHODS: A total of 167 term infants with moderate/severe HIE were assigned randomly to receive either erythropoietin (N = 83) or conventional treatment (N = 84). Recombinant human erythropoietin, at either 300 U/kg (N = 52) or 500 U/kg (N = 31), was administered every other day for 2 weeks, starting <48 hours after birth. The primary outcome was death or disability. Neurodevelopmental outcomes were assessed at 18 months of age. RESULTS: Complete outcome data were available for 153 infants. Nine patients dropped out during treatment, and 5 patients were lost to follow-up monitoring. Death or moderate/severe disability occurred for 35 (43.8%) of 80 infants in the control group and 18 (24.6%) of 73 infants in the erythropoietin group (P = .017) at 18 months. The primary outcomes were not different between the 2 erythropoietin doses. Subgroup analyses indicated that erythropoietin improved long-term outcomes only for infants with moderate HIE (P = .001) and not those with severe HIE (P = .227). No negative hematopoietic side effects were observed. CONCLUSION: Repeated, low-dose, recombinant human erythropoietin treatment reduced the risk of disability for infants with moderate HIE, without apparent side effects.
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48. |
- Zhu, Nali, et al.
(author)
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Environmental fate and behavior of persistent organic pollutants in Shergyla Mountain, southeast of the Tibetan Plateau of China
- 2014
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In: Environmental Pollution. - : Elsevier BV. - 0269-7491 .- 1873-6424. ; 191, s. 166-174
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Journal article (peer-reviewed)abstract
- Pristine mountains are ideal settings to study transport and behavior of persistent organic pollutants (POPs) along gradients of climate and land cover. The present work investigated the concentrations and patterns of 28 organochlorine pesticides (OCPs), 25 polychlorinated biphenyl (PCBs), 13 polybrominated diphenyl ethers (PBDEs), and 3 hexabromocyclododecane (HBCDs) isomers in the air of the Shergyla Mountain, southeastern Tibetan Plateau. Endosulfan І, hexachlorobenzene, pentachlorobenzene, hexachlorocyclohexanes and dichlorodibenzotrichloroethane and its degradation products (DDTs) were the predominant compounds while PBDEs and HBCDs showed the lowest background concentrations. Most of the target POPs had significantly higher concentrations in summer than those in winter. Increasing trends of the concentrations of DDTs and endosulfan were found with increasing altitude on the western slope in the Shergyla Mountain. Potential forest filter effect was observed based on the lower air concentrations of the target POPs in the forest than the ones out of the forest.
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49. |
- Zuo, Zhida, et al.
(author)
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SAFT2 equation of state for the CH4–CO2–H2O–NaCl quaternary system with applications to CO2 storage in depleted gas reservoirs
- 2024
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In: Chemical Geology. - : Elsevier B.V.. - 0009-2541 .- 1872-6836. ; 667
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Journal article (peer-reviewed)abstract
- Understanding the phase equilibria and physical-chemical characteristics of the CH4–CO2–H2O–NaCl quaternary system is important for evaluating costs and risks for the storage of CO2 in depleted natural gas reservoirs as well as fluid inclusion studies. In this study, phase equilibria and thermodynamic properties of this system were investigated through the utilization of a statistical association fluid theory-based (SAFT) equation of state (EOS) at temperatures from 298 to 513 K (25–240 °C), pressures up to 600 bar (60 MPa) and concentration of NaCl up to 6 mol/kgH2O. The model parameters were obtained from the fitting of available experimental data of subsystems (i.e., CH4–H2O, CH4–CO2, and CH4–H2O–NaCl) that were judged to be reliable and incorporation of available parameters for the subsystems (i.e., pure component, CO2–H2O, and CO2–H2O–NaCl). Using the SAFT EOS developed in this study, we predicted the solubility of (CH4 + CO2) gas mixtures in pure H2O and compared it with the available experimental data and the predicted values from four popular numerical simulators. The results indicate that our model can provide reliable predictions for the CH4–CO2–H2O ternary system. Subsequently, we further predicted the phase equilibria and density of the CH4–CO2–H2O–NaCl system with NaCl varying from 0 to 6 mol/kgH2O. We also employed the SAFT EOS to predict the solubility of CO2 and CH4 in the water-alternating-gas process for CO2-enhanced oil recovery, demonstrating good agreement with the simulation results obtained through the Peng-Robinson EOS for predicting the CO2 and CH4 solubility. These predicted thermodynamic properties and phase behaviors in the CH4–CO2–H2O–NaCl system provide quantitative insights into the implications of CO2 storage in depleted oil and gas reservoirs.
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