Publications by authors named "Chenhui Zhang"

63 Publications

Chiral Helimagnetism and One-Dimensional Magnetic Solitons in a Cr-Intercalated Transition Metal Dichalcogenide.

Adv Mater 2021 Jul 24:e2101131. Epub 2021 Jul 24.

Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia.

Chiral magnets endowed with topological spin textures are expected to have promising applications in next-generation magnetic memories. In contrast to the well-studied 2D or 3D magnetic skyrmions, the authors report the discovery of 1D nontrivial magnetic solitons in a transition metal dichalcogenide 2H-TaS via precise intercalation of Cr elements. In the synthetic Cr TaS (CTS) single crystal, the coupling of the strong spin-orbit interaction from TaS and the chiral arrangement of the magnetic Cr ions evoke a robust Dzyaloshinskii-Moriya interaction. A magnetic helix having a short spatial period of ≈25 nm is observed in CTS via Lorentz transmission electron microscopy. In a magnetic field perpendicular to the helical axis, the helical spin structure transforms into a chiral soliton lattice (CSL) with the spin structure evolution being consistent with the chiral sine-Gordon theory, which opens promising perspectives for the application of CSL to fast-speed nonvolatile magnetic memories. This work introduces a new paradigm to soliton physics and provides an effective strategy for seeking novel 2D magnets.
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http://dx.doi.org/10.1002/adma.202101131DOI Listing
July 2021

Surface properties of Tetranychus urticae Koch (Acari: Tetranychidae) and the effect of their infestation on the surface properties of kidney bean (Phaseolus vulgaris L.) hosts.

Pest Manag Sci 2021 Jul 8. Epub 2021 Jul 8.

Department of Applied Chemistry, College of Science, China Agricultural University, Beijing, P. R. China.

Background: The wettability of the target surfaces affects the wetting and deposition of pesticides on them. The properties of leaf surfaces change after infestation by Tetranychus urticae Koch. Studying the surface wettability of T. urticae and the changes in leaf wettability after infestation is important to guide the use of acaricides.

Results: The body surface of T. urticae is an ellipsoidal crown covered with dense cuticle striations and hairs arranged in different directions, which makes the surface of T. urticae rough and hydrophobic. The abaxial surfaces of the leaves are rougher and more hydrophobic than the adaxial surfaces. After infestation by T. urticae, the faded spots were sunken on the adaxial surface and raised on the abaxial surface, where they had formed new wide peaks and valleys. The adaxial surface became obviously rougher and more hydrophobic, while the roughness of the abaxial surface became slightly larger, and the change in hydrophobicity was not obvious. The contact angles of the studied commercial acaricide on these surfaces were greater than 65° and were affected by the infestation. Reducing the surface tension can allow for better wetting of these surfaces and eliminate changes in leaf wettability.

Conclusion: The surfaces of kidney bean leaves became more hydrophobic after infestation by T. urticae with hydrophobic surface. The wettability of the acaricide solution should be adjusted according to the changes in leaf wettability. This study has important theoretical guiding significance for improving effective deposition of acaricide.
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http://dx.doi.org/10.1002/ps.6551DOI Listing
July 2021

Structural basis for chemokine recognition and receptor activation of chemokine receptor CCR5.

Nat Commun 2021 07 6;12(1):4151. Epub 2021 Jul 6.

CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.

The chemokine receptor CCR5 plays a vital role in immune surveillance and inflammation. However, molecular details that govern its endogenous chemokine recognition and receptor activation remain elusive. Here we report three cryo-electron microscopy structures of G protein-coupled CCR5 in a ligand-free state and in complex with the chemokine MIP-1α or RANTES, as well as the crystal structure of MIP-1α-bound CCR5. These structures reveal distinct binding modes of the two chemokines and a specific accommodate pattern of the chemokine for the distal N terminus of CCR5. Together with functional data, the structures demonstrate that chemokine-induced rearrangement of toggle switch and plasticity of the receptor extracellular region are critical for receptor activation, while a conserved tryptophan residue in helix II acts as a trigger of receptor constitutive activation.
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http://dx.doi.org/10.1038/s41467-021-24438-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8260604PMC
July 2021

Melatonin alleviates titanium nanoparticles induced osteolysis via activation of butyrate/GPR109A signaling pathway.

J Nanobiotechnology 2021 Jun 6;19(1):170. Epub 2021 Jun 6.

Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Soochow University, No. 188 Shizi Street, Suzhou, 215006, Jiangsu, China.

Background: Inflammatory osteolysis after total joint replacement (TJR) may cause implant failure, periprosthetic fractures, and be a severe threat to global public health. Our previous studies demonstrated that melatonin had a therapeutic effect on wear-particles induced osteolysis. Gut microbiota is closely related to bone homeostasis, and has been proven to be affected by melatonin. However, whether melatonin could play its anti-osteolysis effects through reprogramming gut microbiota remains elusive.

Results: Here, we demonstrated that melatonin could alleviate Ti-particles induced osteolysis, while this therapeutic effect was blocked by antibiotic cocktail treatment. Interestingly, transplantation of fecal microbiota from mice treated with melatonin reappeared the same beneficial effect. Analysis of the 16S rRNA revealed that melatonin could reverse dysbacteriosis triggered by osteolysis, and elevate the relative abundance of some short chain fatty acid (SCFA) producing bacteria. Moreover, butyrate was enriched by exogenous melatonin administration, while acetate and propionate did not show an evident difference. This was consistent with the results of the metagenomic approach (PICRUSt2) analysis, which revealed a general increase in the synthetic enzymes of butyrate. More importantly, direct supplementation of butyrate could also recapitulate the anti-osteolysis effect of melatonin. Further analysis identified that butyrate alleviated osteolysis via activating its receptor GPR109A, and thus to suppress the activation of NLRP3 inflammasome triggered by Ti-particles.

Conclusions: Taken together, our results suggested that the benefits of melatonin mainly depend on the ability of modulating gut microbiota and regulating butyrate production.
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http://dx.doi.org/10.1186/s12951-021-00915-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8182936PMC
June 2021

Dual-functionalized magnetic bimetallic metal-organic framework composite for highly specific enrichments of phosphopeptides and glycopeptides.

Anal Chim Acta 2021 May 16;1158:338412. Epub 2021 Mar 16.

Shanghai Key Laboratory of Functional Materials Chemistry,School of Chemistry & Molecular Engineering, East China University of Science and Technology, Shanghai, PR China.

In this work, a dual-functionalized magnetic bimetallic metal-organic framework composite denoted as [email protected]@(Zr-Ti-MOF)-NH was ingeniously designed and fabricated by a facial layer-by-layer assembly technique. The composite not only exhibited strong affinity for phosphopeptide due to the coexistence of Zr-O clusters and Ti-O clusters, but also owned great hydrophilicity for glycopeptides relying on abundant hydrophilic NH groups, meeting the demand for simultaneously enrichment and sequential elution of phosphopeptides and glycopeptides. As expected, the synthesized composite showed great selectivity (1:2000 M ratio of β-casein:BSA; 1:50 M ratio of IgG:BSA), good sensitivity (1 fmol μL for both α-casein and IgG), and good capacity (80 mg g for α-casein and 200 mg g for IgG). By using sequential elution strategy, 29 phosphopeptides and 24 glycopeptides from α-casein and IgG digests mixture could be simultaneously enriched and respectively detected through a single-step enrichment and sequential elution method. Furthermore, the composite was successfully applied to the analysis of intricate biological samples. 4 endogenous phosphopeptides and 20 phosphopeptides were trapped from human serum and non-fat milk tryptic digest respectively. From 0.5 mg of tryptic digest of rat brain, 141 N-linked glycopeptides corresponding to 127 glycoproteins and 918 phosphopeptides corresponding to 397 phosphoproteins were enriched simultaneously and identified respectively, proving the [email protected]@(Zr-Ti-MOF)-NH to be a dependable candidate for the simultaneously enrichment of trace phosphopeptides and glycopeptides in intricate biological samples.
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http://dx.doi.org/10.1016/j.aca.2021.338412DOI Listing
May 2021

Giant Ferroelectric Resistance Switching Controlled by a Modulatory Terminal for Low-Power Neuromorphic In-Memory Computing.

Adv Mater 2021 May 15;33(21):e2008709. Epub 2021 Apr 15.

Physical Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia.

Ferroelectrics have been demonstrated as excellent building blocks for high-performance nonvolatile memories, including memristors, which play critical roles in the hardware implementation of artificial synapses and in-memory computing. Here, it is reported that the emerging van der Waals ferroelectric α-In Se can be used to successfully implement heterosynaptic plasticity (a fundamental but rarely emulated synaptic form) and achieve a resistance-switching ratio of heterosynaptic memristors above 10 , which is two orders of magnitude larger than that in other similar devices. The polarization change of ferroelectric α-In Se channel is responsible for the resistance switching at various paired terminals. The third terminal of α-In Se memristors exhibits nonvolatile control over channel current at a picoampere level, endowing the devices with picojoule read-energy consumption to emulate the associative heterosynaptic learning. The simulation proves that both supervised and unsupervised learning manners can be implemented in α-In Se neutral networks with high image recognition accuracy. Moreover, these heterosynaptic devices can naturally realize Boolean logic without an additional circuit component. The results suggest that van der Waals ferroelectrics hold great potential for applications in complex, energy-efficient, brain-inspired computing systems and logic-in-memory computers.
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http://dx.doi.org/10.1002/adma.202008709DOI Listing
May 2021

Fine genetic mapping of the chromosome 11q23.3 region in a Han Chinese population: insights into the apolipoprotein genes underlying the blood lipid-lipoprotein variances.

J Genet Genomics 2020 12 13;47(12):756-769. Epub 2021 Feb 13.

Department of Genetics, Shanghai-MOST Key Laboratory of Health and Disease Genomics, Chinese National Human Genome Center at Shanghai and Shanghai Academy of Science and Technology, Shanghai 200025, China. Electronic address:

The unusual chromosome 11q23.3 harboring the apolipoprotein (APO) gene cluster has been well documented for its essential roles in plasma lipid-related traits and atherosclerotic cardiovascular diseases. However, its genetic architecture and the potential biological mechanisms underlying complex phenotypes have not been well assessed. We conducted a study for this target region in a Han Chinese population through a stepwise forward framework based on massive parallel sequencing, association analyses, genetic fine mapping, and functional interpretation. The present study identified new meaningful genetic associations that were not simply determined by statistical significance. In addition to the APOA5 gene, we found robust evidence of the genetic commitments of APOC3 and APOA1 to blood lipids. Several variants with high confidence were prioritized along with the potential biological mechanism interpretations in the wake of adaptive fine-mapping analyses. rs2849174 in the APOC3 enhancer was discovered with an unrivaled posterior probability of causality for triglyceride levels and could mediate APOC3 expression through enhancer activity modulated by a combination of histone modifications and transcription factor accessibility. Similarly, multiple lines of evidence converged in favor of rs3741297 as a causal variant influencing high-density lipoprotein cholesterol. Our findings provided novel insights into this genomic locus in the Chinese population.
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http://dx.doi.org/10.1016/j.jgg.2020.11.010DOI Listing
December 2020

Updating and identifying three novel variants of the gene in Chinese Han patients with psoriasis.

J Genet 2020 ;99

Department of Dermatology, Huashan Hospital, Shanghai Medical College of Fudan University, Shanghai 200040, People's Republic of China.

Psoriasis-2 (PSORS2) is caused by the heterozygous mutation of the caspase recruitment domain 14 () gene on chromosome 17q25. To evaluate the contribution of variants in psoriasis of the Chinese Han population, we performed deep sequencing of the gene in 372 Chinese Han patients with psoriasis. The exonic nucleotide variants were confirmed by Sanger sequencing in the affected individuals and 1114 controls. In 27 patients with psoriasis, we identified 15 variations, including three novel variants: c.381C[G (p.Cys127Trp), c.712A[G (p.Met238Val) and c.2260_2261delinsGG (p.Gln754Gly). These findings could enrich and update the Human Gene Mutation Database of variants for psoriasis.
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July 2021

Berry Phase Engineering in SrRuO/SrIrO/SrTiO Superlattices Induced by Band Structure Reconstruction.

ACS Nano 2021 Mar 19;15(3):5086-5095. Epub 2021 Feb 19.

Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia.

The Berry phase, which reveals the intimate geometrical structure underlying quantum mechanics, plays a central role in the anomalous Hall effect. In this work, we observed a sign change of Berry curvatures at the interface between the ferromagnet SrRuO (SRO) layer and the SrIrO (SIO) layer with strong spin-orbit coupling. The negative Berry curvature at the interface, induced by the strongly spin-orbit-coupled Ir 5d bands near the Fermi level, makes the SRO/SIO interface different from the SRO layer that has a positive Berry curvature. These opposite Berry curvatures led to two anomalous Hall effect (AHE) channels with opposite signs at the SRO/SIO interface and in the SRO layer, respectively, resulting in a hump-like feature in the Hall resistivity loop. This observation offers a straightforward explanation of the hump-like feature that is usually associated with the chiral magnetic structure or magnetic skyrmions. Hence, this study provides evidence to oppose the widely accepted claim that magnetic skyrmions induce the hump-like feature.
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http://dx.doi.org/10.1021/acsnano.0c10200DOI Listing
March 2021

Epitaxial growth of large-grain-size ferromagnetic monolayer CrI for valley Zeeman splitting enhancement.

Nanoscale 2021 Feb 28;13(5):2955-2962. Epub 2021 Jan 28.

Key Laboratory of Flexible Electronics & Institute of Advanced Materials, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, 30 South Puzhu Road, Nanjing 211816, China.

Two-dimensional (2D) magnetic CrI has received considerable research attention because of its intrinsic features, including insulation, Ising ferromagnetism, and stacking-order-dependent magnetism, as well as potential in spintronic applications. However, the current strategy for the production of ambient-unstable CrI thin layer is limited to mechanical exfoliation, which normally suffers from uncontrollable layer thickness, small size, and low yet unpredictable yield. Here, via a confined vapor epitaxy (CVE) method, we demonstrate the mass production of flower-like CrI monolayers on mica. Interestingly, we discovered the crucial role of K ions on the mica surface in determining the morphology of monolayer CrI, reacting with precursors to form a KI buffer layer. Meanwhile, the transport agent affects the thickness and size of the as-grown CrI. Moreover, the Curie temperature of CrI is greatly affected by the interaction between CrI and the substrate. The monolayer CrI on mica could act as a magnetic substrate for valley Zeeman splitting enhancement of WSe. We reckon our work represents a major advancement in the mass production of monolayer 2D CrI and anticipate that our growth strategy may be extended to other transition metal halides.
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http://dx.doi.org/10.1039/d0nr08248aDOI Listing
February 2021

Efficient preparation of c-di-AMP at gram-scale using an immobilized Vibrio cholerae dinucleotide cyclase DncV.

Enzyme Microb Technol 2021 Feb 4;143:109700. Epub 2020 Nov 4.

Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan 250012, China. Electronic address:

Cyclic di-AMP is a bacterial nucleotide second messenger and evaluated as a potential vaccine adjuvant candidate. Here, we report a practical and economical enzymatic method for gram-scale preparation of c-di-AMP using an immobilized Vibrio cholerae dinucleotide cyclase DncV. The method mainly includes four steps: preparation of DncV-immobilized resin, enzymatic synthesis of c-di-AMP, purification using macroporous absorption resin SP207, and desiccation using rotary evaporation and lyophilization. Enzymatic synthesis is the most critical step, and almost all substrate ATP was converted to c-di-AMP under an optimum condition in which 300 mL of 300 mM NHAc/NH pH 9.5 buffer supplemented with 20 mM MnCl, 10 mM ATP and 4 mL of DncV-immobilized resin containing ∼19 mg DncV were incubated at 30 °C overnight. After purification, up to 1 g of the diammonium salt of c-di-AMP with weight purity of ≥98% was obtained as white powder, which corresponds to an overall yield of ∼80% based on the ATP input into the reaction. The method is easily performed in laboratory to prepare c-di-AMP on a gram scale and could be used in industry on a large scale.
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http://dx.doi.org/10.1016/j.enzmictec.2020.109700DOI Listing
February 2021

Role of Buffer Layer and Building Unit in the Monolayer CrI Growth: A First-Principles Perspective.

J Phys Chem Lett 2020 Nov 27;11(21):9453-9460. Epub 2020 Oct 27.

Frontiers Science Center for Flexible Electronics, Xi'an Institute of Flexible Electronics (IFE) and Xi'an Institute of Biomedical Materials & Engineering, Northwestern Polytechnical University, Xi'an 710072, China.

CrI, a two-dimensional layered material, has recently attracted a lot of research interest due to its exotic magnetic property. However, the synthesis of a CrI monolayer (ML) by vapor-phase deposition has not been achieved by current experimental endeavors, which require a better understanding of the vapor-phase growth mechanism involved. In this study, we theoretically simulate the growth of the CrI ML on the Si(111) surface by using a first-principles calculation. Our key finding is that an iodine buffer layer on the Si surface is crucial to the formation of the CrI ML by stabilizing the precursor and also reacting with the precursor. Moreover, our simulation reveals that the CrI cluster as the growth building unit, which can be formed by controlling the chemical potential of the I source, is preferred for the formation of CrI ML. We think that our work will provide insightful guidance for the experimental synthesis of CrI ML in the future.
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http://dx.doi.org/10.1021/acs.jpclett.0c02717DOI Listing
November 2020

Multiple modulations of supramolecular assemblies from a natural triterpenoid-tailored bipyridinium amphiphile.

J Colloid Interface Sci 2021 Feb 6;584:92-102. Epub 2020 Oct 6.

Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China. Electronic address:

As the applications of supramolecular assemblies are ultimately inscribed in their nanostructures, strategies that can precisely fabricate and regulate supramolecular architectures from small molecules are of great importance. Herein, in this research multiple modulations of supramolecular assembled structures of a natural triterpenoid-tailored bipyridinium amphiphile, 1-[2-(methyl glycyrrhetate)-2-oxoethyl]-[4,4']bipyridinium bromide (MGBP), have been achieved by adjusting solvents or counterions. Depending on the polarity of solvents, MGBP assembled into nanofibers, helices, pentagon and hexagon microsheets, respectively. Moreover, the nanofibers in methanol/water can transform into ribbons, robust fibers and fiber bundles by addition of counterions with different ionic sizes and valences. This work presents a simple and feasible methodology to modulate assembly structures of a natural triterpenoid-based amphiphile, which may expand the application of natural products in supramolecular materials.
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http://dx.doi.org/10.1016/j.jcis.2020.09.125DOI Listing
February 2021

Seasonal Variation in the Rhizosphere and Non-Rhizosphere Microbial Community Structures and Functions of Hu.

Microorganisms 2020 Sep 10;8(9). Epub 2020 Sep 10.

Key Laboratory of Cultivation and Protection for Non-Wood Forest Trees, Ministry of Education, Central South University of Forestry and Technology, Changsha, Hunan 410004, China.

Hu, endemic to China, is a predominant oilseed crop, due to its high yield and pathogen resistance. Past studies have focused on the aboveground parts of whereas the microbial community of the rhizosphere has not been reported yet. This study is the first time to explore the influence of seasonal variation on the microbial community in the rhizosphere of using high-throughput sequencing. The results showed that the dominant bacteria in the rhizosphere of were Chloroflexi, Proteobacteria, Acidobacteria, Actinobacteria, and Planctomycetes, and the dominant fungi were Ascomycota, Basidiomycota, and Mucoromycota. Seasonal variation has significant effects on the abundance of the bacterial and fungal groups in the rhizosphere. A significant increase in bacterial abundance and diversity in the rhizosphere reflected the root activity of in winter. Over the entire year, there were weak correlations between microorganisms and soil physiochemical properties in the rhizosphere. In this study, we found that the bacterial biomarkers in the rhizosphere were chemoorganotrophic Gram-negative bacteria that grow under aerobic conditions, and fungal biomarkers, such as , and , exhibited protection against pathogens in the rhizosphere. In the rhizosphere of , the dominant functions of the bacteria included nitrogen metabolism, oxidative phosphorylation, glycine, serine and threonine metabolism, glutathione metabolism, and sulfur metabolism. The dominant fungal functional groups were endophytes and ectomycorrhizal fungi of a symbiotroph trophic type. In conclusion, seasonal variation had a remarkable influence on the microbial communities and functions, which were also significantly different in the rhizosphere and non-rhizosphere of . The rhizosphere of provides suitable conditions with good air permeability that allows beneficial bacteria and fungi to dominate the soil microbial community, which can improve the growth and pathogen resistance of
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http://dx.doi.org/10.3390/microorganisms8091385DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7564921PMC
September 2020

Mobility-Fluctuation-Controlled Linear Positive Magnetoresistance in 2D Semiconductor BiOSe Nanoplates.

ACS Nano 2020 Sep 19;14(9):11319-11326. Epub 2020 Aug 19.

Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia.

Linear magnetoresistance is generally observed in polycrystalline zero-gap semimetals and polycrystalline Dirac semimetals with ultrahigh carrier mobility. We report the observation of positive and linear magnetoresistance in a single-crystalline semiconductor BiOSe grown by chemical vapor deposition. Both Se-poor and Se-rich BiOSe single-crystalline nanoplates display a linear magnetoresistance at high fields. The Se-poor BiOSe exhibits a typical 2D conduction feature with a small effective mass of 0.032. The average transport Hall mobility, which is lower than 5500 cm V s, is significantly reduced, compared with the ultrahigh quantum mobility as high as 16260 cm V s. More interestingly, the pronounced Shubnikov-de Hass oscillations can be clearly observed from the very large and nearly linear magnetoresistance (>500% at 14 T and 2 K) in Se-poor BiOSe. A close analysis of the results reveals that the large and linear magnetoresistance observed can be ascribed to the spatial mobility fluctuation, which is strongly supported by Fermi energy inhomogeneity in the nanoplate samples detected using an electrostatic force microscopy images and multiple frequencies in a Shubnikov-de Hass oscillation. On the contrary, the Se-rich BiOSe exhibits a transport mobility (<300 cm V s) much smaller than that observed in Se-poor samples and shows a much smaller linear magnetoresistance ratio (less than 150% at 14 T and 2 K). More strikingly, no Shubnikov-de Hass oscillations can be observed. Therefore, the linear magnetoresistance in Se-rich BiOSe is governed by the average mobility rather than the mobility fluctuation.
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http://dx.doi.org/10.1021/acsnano.0c03346DOI Listing
September 2020

Synthesis of a molecularly imprinted polymer using MOF-74(Ni) as matrix for selective recognition of lysozyme.

Anal Bioanal Chem 2020 Oct 15;412(26):7227-7236. Epub 2020 Aug 15.

Shanghai Key Laboratory of Functional Materials Chemistry, School of Chemistry & Molecular Engineering, East China University of Science and Technology, Shanghai, 200237, China.

A molecularly imprinted polymer and metal organic framework were combined to prepare protein imprinted material. MOF-74(Ni) was used as a matrix to prepare surface-imprinted material with lysozyme as a template and polydopamine as an imprinting polymer. MOF-74(Ni) not only provides a large surface area (150.0 m/g) to modify the polymer layer with more recognition sites (Wt (Ni) = 42.24%), but also facilitates the immobilization of lysozyme by using the chelation between Ni of the MOF-74(Ni) and protein. The thin polydopamine layer (10 nm) of the molecularly imprinted material (named [email protected]) enables surface imprinting. Benefiting from the thin polymer layer, [email protected] reached adsorption equilibrium within 10 min. The maximum adsorption capacity reaches 313.5 mg/g with the highest imprinting factor (IF) of 7.8. The specific recognition sites can distinguish target lysozyme from other proteins such as egg albumin (OVA), bovine serum albumin (BSA) and ribonuclease A (RNase A). The material was successfully applied to separation of lysozyme from egg white. Graphical abstract.
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http://dx.doi.org/10.1007/s00216-020-02855-7DOI Listing
October 2020

Superlubrication obtained with mixtures of hydrated ions and polyethylene glycol solutions in the mixed and hydrodynamic lubrication regimes.

J Colloid Interface Sci 2020 Nov 25;579:479-488. Epub 2020 Jun 25.

Faculty of Pharmacy, Université de Montréal, Montreal, Quebec H3C 3J7, Canada.

Hypothesis: Superlubricity is known to dramatically reduce frictional energy consumption and to improve service life of mechanical devices and biological systems. However, reduction of wear during the running-in period of friction pairs, especially under high contact pressures, still remains an unresolved issue affecting all machines.

Experiments: Here the lubrication, adsorption, and conformational properties of hydrated ions and polyethylene glycol (PEG) mixtures were evaluated at different mass fractions and concentrations of PEG and salts by ball-on-disc tribometer, ζ-potential, quartz crystal microbalance with dissipation (QCM-D), and dynamic light scatting (DLS) analyses.

Findings: These mixtures exhibited superlubricity between SiN and sapphire surfaces in a wide range of concentrations and ions valency. Interestingly, a running-in phase shorter than 1 min and low wear rate of 1.85 μm/(N·m) were observed at contact pressures up to 555 MPa, significantly higher to earlier findings. PEG chains retain random coils filling the bulk of the interfacial film without strongly adsorbing on the interfaces but significantly increasing the viscosity of lubricating film, thereby favoring hydrodynamic lubrication. Hydrated ions are strongly adsorbed on the negatively charged ceramic surfaces, ensuring a sustained hydration effect maintaining superlubricity. The outstanding lubrication characteristics of the PEG/ions mixtures were attributed to the synergistic action of hydration and hydrodynamic lubrication, which appears as a promising avenue for developing new green lubricants and has implications for industrial and biological applications.
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http://dx.doi.org/10.1016/j.jcis.2020.06.095DOI Listing
November 2020

A simple and effective strategy to enhance the stability and solid-liquid interfacial interaction of an emulsion by the interfacial dilational rheological properties.

Soft Matter 2020 Jun;16(24):5650-5658

Department of Applied Chemistry, College of Science, China Agricultural University, Beijing 100193, China.

The development of an emulsion is an important challenge in many fields, such as agrochemicals, pharmaceutics, paints, cosmetics, inkjet printing, and food science. However, the traditional strategies that refer to the empirical value and complex secondary additives cannot reflect the influence of the structure, content, compound, and adsorption of emulsifiers. Here, we propose a simple and effective strategy to develop the emulsion, wherein the emulsifiers are chosen based on the dilational rheological properties of the interfacial films at the molecular level. The dilational rheological properties of polyoxyethylene (80) castor oil (EL-80), sorbitan monostearate (Span 60), and their emulsions were explored by the oscillating drop method. Based on the dilational rheological properties, the emulsions were prepared by the phase inversion emulsification technique. The results showed that the emulsion was stable and realized effective solid-liquid interfacial interaction, which was attributed to the large dilational modulus (intermolecular interaction) at the oil/water interface and loss modulus (molecular diffusion exchange) at the air/water interface. These factors reduced the Ostwald ripening and coalescence, and finally increased the spreading diameter. Additionally, the prochloraz 25% emulsion in water (EW) and difenoconazole 20% EW were developed to verify the feasibility of the strategy. Therefore, this research advances the understanding of an emulsion by interfacial dilational rheological properties, which can provide a simple and effective strategy to develop a stable emulsion and achieve an effective solid-liquid interfacial interaction of the emulsion.
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http://dx.doi.org/10.1039/d0sm00638fDOI Listing
June 2020

Unveiling defect-mediated carrier dynamics in monolayer semiconductors by spatiotemporal microwave imaging.

Proc Natl Acad Sci U S A 2020 Jun 8;117(25):13908-13913. Epub 2020 Jun 8.

Department of Physics, The University of Texas at Austin, Austin, TX 78712;

The optoelectronic properties of atomically thin transition-metal dichalcogenides are strongly correlated with the presence of defects in the materials, which are not necessarily detrimental for certain applications. For instance, defects can lead to an enhanced photoconduction, a complicated process involving charge generation and recombination in the time domain and carrier transport in the spatial domain. Here, we report the simultaneous spatial and temporal photoconductivity imaging in two types of WS monolayers by laser-illuminated microwave impedance microscopy. The diffusion length and carrier lifetime were directly extracted from the spatial profile and temporal relaxation of microwave signals, respectively. Time-resolved experiments indicate that the critical process for photoexcited carriers is the escape of holes from trap states, which prolongs the apparent lifetime of mobile electrons in the conduction band. As a result, counterintuitively, the long-lived photoconductivity signal is higher in chemical-vapor deposited (CVD) samples than exfoliated monolayers due to the presence of traps that inhibits recombination. Our work reveals the intrinsic time and length scales of electrical response to photoexcitation in van der Waals materials, which is essential for their applications in optoelectronic devices.
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http://dx.doi.org/10.1073/pnas.2004106117DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7322012PMC
June 2020

Enhancement of critical current density in a superconducting NbSe step junction.

Nanoscale 2020 Jun;12(22):12076-12082

Physical Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia.

We investigate the transport properties of a NbSe2 nanodevice consisting of a thin region, a thick region and a step junction. The superconducting critical current density of each region of the nanodevice has been studied as a function of temperature and magnetic field. We find that the critical current density has similar values for both the thin and thick regions away from the junction, while the critical current density of the thin region of the junction increases to approximately 1.8 times as compared with the values obtained for the other regions. We attribute such an enhancement of critical current density to the vortex pinning at the surface step. Our study verifies the enhancement of the critical current density by the geometrical-type pinning and sheds light on the application of 2D superconductors.
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http://dx.doi.org/10.1039/d0nr03902kDOI Listing
June 2020

Topological electronic state and anisotropic Fermi surface in half-Heusler GdPtBi.

J Phys Condens Matter 2020 Apr 30;32(35):355707. Epub 2020 Apr 30.

King Abdullah University of Science and Technology (KAUST), Division of Physical Science and Engineering (PSE), Thuwal 23955-6900, Saudi Arabia.

Half-Heusler alloys possess unique and desirable physical properties due to their thermoelectricity, magnetism, superconductivity, and weak antilocalization effects. These properties have become of particular interest since the recent discovery of topological Weyl semimetal state for which the electronic bands are dispersed linearly around one pair of Weyl nodes, with opposite chirality (i.e., chiral anomaly). Here, we report the transport signatures of topological electronic state in a half-Heusler GdPtBi single crystal. We show that the non-trivial π Berry phase, negative magnetoresistance and giant planner Hall effect arise from the chiral anomaly and that the Shubnikov-de Haas oscillation frequency in GdPtBi is angle-dependent with an anisotropic Fermi surface (FS). All transport signatures not only demonstrate the topological electronic state in half-Heusler GdPtBi crystals, but also describe the shape of the anisotropy FS.
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http://dx.doi.org/10.1088/1361-648X/ab8ec8DOI Listing
April 2020

Atomic-scale insights into the interfacial instability of superlubricity in hydrogenated amorphous carbon films.

Sci Adv 2020 Mar 27;6(13):eaay1272. Epub 2020 Mar 27.

State Key Laboratory of Tribology, Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China.

The origin of instability or even disappearance of the superlubricity state in hydrogenated amorphous carbon (a-C:H) film in the presence of oxygen or water molecules is still controversial. Here, we address this puzzle regarding the tribochemical activities of sliding interfaces at the nanoscale. The results reveal that gaseous oxygen molecules disable the antifriction capacity of a-C:H by surface dehydrogenation of tribo-affected hydrocarbon bonds. In comparison, oxygen incorporation into the hydrocarbon matrix induces the formation of a low-density surface shear band, owing to which the friction state depends on the oxygen content. High friction of a-C:H film in humid environment originates from the "tumor-like" heterogeneous structures as formed in the highly oxidized tribolayer. Notably, an appropriate doping of silicon can completely shield the moisture effect by forming a silica-like tribolayer. These outcomes shed substantial lights upon the roadmap for achieving robust superlubricity of carbon films in a wide range of environments.
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http://dx.doi.org/10.1126/sciadv.aay1272DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7101219PMC
March 2020

Solvothermal synthesis of InNbO cubes for efficient degradation of pefloxacin.

Spectrochim Acta A Mol Biomol Spectrosc 2020 Jun 9;234:118247. Epub 2020 Mar 9.

Department of Applied Chemistry, Xi'an University of Technology, 5 Jinhua South Road, Xi'an, Shaanxi 710048, PR China. Electronic address:

A novel solvothermal process for synthesizing InNbO nanomaterials was developed. In this manner, a series of InNbO samples was synthesized. It was shown that reaction temperature and precursor pH had strong influence on the attributes of InNbO samples. The X-ray diffraction patterns revealed that all the samples possessed monoclinic structure and the optimal reaction condition was found at 250 °C with a pH of 5. Scanning electron microscopy images of different InNbO samples showed various morphologies. Transmission electron microscopy verified the synthesized InNbO-pH 5 was single-crystal cubes. X-ray photoelectron spectra verified the existence of In, Nb, and O in InNbO-pH 5 sample. The band gap of InNbO-pH 5 was calculated to be 2.51 eV. The photocurrent intensity of InNbO-pH 5 was the highest among the prepared samples. The photocatalytic degradation of pefloxacin was investigated using these samples. The InNbO-pH 5 exhibited best degradation efficiency among these samples. The removal efficiency of pefloxacin with InNbO-pH 5 could reach 80.2% in 60 min. Based on free radical capture results, superoxide radicals and holes showed to be the dominant active species. In addition, UHPLC/MS/MS was used to identify the degradation intermediates. Five new pefloxacin degradation products were found and possible degradation pathways were suggested.
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http://dx.doi.org/10.1016/j.saa.2020.118247DOI Listing
June 2020

Identification of Novel Compound Heterozygous Mutations in the Gene of a Chinese Patient Diagnosed With Giant Axonal Neuropathy.

Front Neurosci 2020 25;14:85. Epub 2020 Feb 25.

Wenzhou People's Hospital, Wenzhou Maternal and Child Health Care Hospital, The Third Clinical Institute Affiliated to Wenzhou Medical University, Wenzhou, China.

Giant axonal neuropathy (GAN) is a very rare autosomal recessive disorder characterized by abnormally large and dysfunctional neuronal axons. Mutations in the gene have been identified as the cause of this disorder. In this report, we performed a detailed phenotypic assessment of a Chinese patient with GAN. An array-based exon capture test and targeted next-generation sequencing were used to detect the suspected mutation sites. Compound heterozygous mutations of p.S79L (c.236C > T) in the BTB domain and p.T489S (c.1466C > G) in the kelch domain were identified in the proband's genome. S79L was a known mutation, and T489S was reported for the first time. The p.S79L and p.T489S were confirmed in the proband's mother and father, respectively. Both mutations were located in highly conserved regions and affected the predicted protein crystal structures. The proband's sural biopsy revealed the classical GAN phenotype of swollen axons filled with closely packed neurofilaments. The combined application of the next-generation sequencing platform and bioinformatics analyses was an effective method for diagnosing GAN. The novel compound mutations of S79L and T489S in the gene were likely the cause of the patient's GAN symptoms. Our findings enrich the spectrum of mutations associated with this rare type of axonopathy.
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http://dx.doi.org/10.3389/fnins.2020.00085DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7052293PMC
February 2020

Macroscale Superlubricity Enabled by Graphene-Coated Surfaces.

Adv Sci (Weinh) 2020 Feb 19;7(4):1903239. Epub 2020 Jan 19.

Key Laboratory for Precision and Non-Traditional Machining Technology of Ministry of Education Dalian University of Technology Dalian 116024 China.

Friction and wear remain the primary modes for energy dissipation in moving mechanical components. Superlubricity is highly desirable for energy saving and environmental benefits. Macroscale superlubricity was previously performed under special environments or on curved nanoscale surfaces. Nevertheless, macroscale superlubricity has not yet been demonstrated under ambient conditions on macroscale surfaces, except in humid air produced by purging water vapor into a tribometer chamber. In this study, a tribological system is fabricated using a graphene-coated plate (GCP), graphene-coated microsphere (GCS), and graphene-coated ball (GCB). The friction coefficient of 0.006 is achieved in air under 35 mN at a sliding speed of 0.2 mm s for 1200 s in the developed GCB/GCS/GCP system. To the best of the knowledge, for the first time, macroscale superlubricity on macroscale surfaces under ambient conditions is reported. The mechanism of macroscale superlubricity is due to the combination of exfoliated graphene flakes and the swinging and sliding of the GCS, which is demonstrated by the experimental measurements, ab initio, and molecular dynamics simulations. These findings help to bridge macroscale superlubricity to real world applications, potentially dramatically contributing to energy savings and reducing the emission of carbon dioxide to the environment.
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http://dx.doi.org/10.1002/advs.201903239DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7029642PMC
February 2020

Origins of Superlubricity Promoted by Hydrated Multivalent Ions.

J Phys Chem Lett 2020 Jan 18;11(1):184-190. Epub 2019 Dec 18.

State Key Laboratory of Tribology, Tsinghua University , Beijing 100084 , China.

Strong hydration repulsion exists between two negatively charged surfaces in the alkali metal salt solutions, together with the fluid response to the shear of hydration layers, leading to superlubricity. However, whether the multivalent ions can obtain superlubricity has not been revealed yet. Here, we evaluate the lubrication and adsorption properties of multivalent ions at different concentrations between SiN and sapphire surfaces. The divalent and trivalent ions exhibit extremely low friction coefficients of 0.005-0.006 and 0.002-0.004, respectively, under contact pressures above 0.25 GPa, and three trivalent ions can achieve superlubricity at quite low sliding speeds (3.1 mm/s), which is a significant breakthrough for superlubricity under boundary lubrication. Moreover, compared with monovalent ions, divalent ions can reduce surface potential and lower surface charge density even further, and trivalent ions can neutralize the negatively charged ceramic surfaces and even lead to charge inversion due to excess adsorption of the cations, which ensures strong adsorption of hydrated multivalent ions on friction surfaces.
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http://dx.doi.org/10.1021/acs.jpclett.9b03098DOI Listing
January 2020

Fractal-Theory-Based Control of the Shape and Quality of CVD-Grown 2D Materials.

Adv Mater 2019 Aug 2;31(35):e1902431. Epub 2019 Jul 2.

Physical Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia.

The precise control of the shape and quality of 2D materials during chemical vapor deposition (CVD) processes remains a challenging task, due to a lack of understanding of their underlying growth mechanisms. The existence of a fractal-growth-based mechanism in the CVD synthesis of several 2D materials is revealed, to which a modified traditional fractal theory is applied in order to build a 2D diffusion-limited aggregation (2D-DLA) model based on an atomic-scale growth mechanism. The strength of this model is validated by the perfect correlation between theoretically simulated data, predicted by 2D-DLA, and experimental results obtained from the CVD synthesis of graphene, hexagonal boron nitride, and transition metal dichalcogenides. By applying the 2D-DLA model, it is also discovered that the single-domain net growth rate (SD-NGR) plays a crucial factor in governing the shape and quality of 2D-material crystals. By carefully tuning SD-NGR, various fractal-morphology high-quality single-crystal 2D materials are synthesized, achieving, for the first time, the precise control of 2D-material CVD growth. This work lays the theoretical foundation for the precise adjustment of the morphologies and physical properties of 2D materials, which is essential to the use of fractal-shaped nanomaterials for the fabrication of new-generation neural-network nanodevices.
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http://dx.doi.org/10.1002/adma.201902431DOI Listing
August 2019

Tribochemical Behaviors of Onion-like Carbon Films as High-Performance Solid Lubricants with Variable Interfacial Nanostructures.

ACS Appl Mater Interfaces 2019 Jul 2;11(28):25535-25546. Epub 2019 Jul 2.

State Key Laboratory of Tribology , Tsinghua University , Beijing 100084 , China.

Onion-like carbon (OLC), spherical nanoparticles consisting of carbon shells, is capable of providing exceptional lubrication effects. Nevertheless, the underlying mechanism, especially the tribo-induced evolution of interfacial nanostructures and their correlation with the friction states, is not clear. In this work, OLC films with a thickness of ∼1 μm were synthesized by electrophoretic deposition on the mirror-polished stainless steel. The lubricity was evaluated by tailoring the sliding aspects including applied normal load, contact time, and counterface materials. It is found that the friction reduction level is highly dependent on the material transfer and transformation of the OLC surface and the physicochemical nature of the as-formed tribolayer in the contact areas. The subsurface of the OLC film always undergoes a deep amorphization transformation upon sliding. It is interesting to note that the tribolayer formed on the bare steel ball is mainly composed of highly ordered graphene-like nanoflakes derived from the sliding-induced degradation of OLC nanospheres. In comparison, the nanospherical carbon structure can be retained in the topmost subsurface of the tribolayer formed on the ceramic SiN ball. Such a nanosphere-/amorphization-coupled interface is capable of providing a robust lubrication state under high contact stresses. The findings identify a new lubrication mechanism for the spherical carbon nanostructure, rendering them effective solid lubricants.
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http://dx.doi.org/10.1021/acsami.9b06099DOI Listing
July 2019

Identification of gene variants in 130 Han Chinese patients with hypospadias by targeted next-generation sequencing.

Mol Genet Genomic Med 2019 08 20;7(8):e827. Epub 2019 Jun 20.

Department of Paediatrics, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.

Background: Hypospadias is a common congenital malformation of male external genitalia, which mainly manifests as an abnormal urethral opening on the ventral side of the penis. The etiology and clinical phenotype of hypospadias is highly heterogeneous, and its clinical diagnosis is challenging. Currently, over 70% of patients have an unknown etiology. Here, we performed a targeted analysis of gene mutations in 130 patients with hypospadias of unknown etiology to find the precise genetic cause.

Methods: We developed a targeted next-generation sequencing (NGS) panel, encompassing the exon coding regions of 105 genes involved in external genitalia and urogenital tract development and performed sequencing analysis on 130 children with hypospadias of unknown etiology.

Results: In total, 25 patients with hypospadias (19.2%) were found to have 20 mutations among the nine genes involved in external genitalia and urogenital tract development, including 16 reported and four novel mutation sites. Twenty-two patients (16.9%) had diagnostic variants. Multiple genetic mutations were identified in three of the 25 patients. Hypospadias combined with micropenis was the most common phenotype (68%) in 25 patients.

Conclusions: Higher frequency mutations were identified in SRD5A2 (52%) and AR (24%) in our patient cohort. Middle or posterior hypospadias with micropenis may be significant indicators of genetic variations. Polygenic inheritance may be a rare genetic cause of hypospadias.
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http://dx.doi.org/10.1002/mgg3.827DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6687654PMC
August 2019

Genomic and Transcriptomic Landscape of Triple-Negative Breast Cancers: Subtypes and Treatment Strategies.

Cancer Cell 2019 03 7;35(3):428-440.e5. Epub 2019 Mar 7.

Shanghai-MOST Key Laboratory of Health and Disease Genomics, Chinese National Human Genome Center at Shanghai (CHGC) and Shanghai Industrial Technology Institute (SITI), 250 Bibo Road, Shanghai 201203, P.R. China.

We comprehensively analyzed clinical, genomic, and transcriptomic data of a cohort of 465 primary triple-negative breast cancer (TNBC). PIK3CA mutations and copy-number gains of chromosome 22q11 were more frequent in our Chinese cohort than in The Cancer Genome Atlas. We classified TNBCs into four transcriptome-based subtypes: (1) luminal androgen receptor (LAR), (2) immunomodulatory, (3) basal-like immune-suppressed, and (4) mesenchymal-like. Putative therapeutic targets or biomarkers were identified among each subtype. Importantly, the LAR subtype showed more ERBB2 somatic mutations, infrequent mutational signature 3 and frequent CDKN2A loss. The comprehensive profile of TNBCs provided here will serve as a reference to further advance the understanding and precision treatment of TNBC.
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http://dx.doi.org/10.1016/j.ccell.2019.02.001DOI Listing
March 2019
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