Publications by authors named "Chengjie Xia"

11 Publications

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Structural characterization and statistical properties of jammed soft ellipsoid packing.

Soft Matter 2021 Mar;17(10):2963-2972

Shanghai Key Laboratory of Magnetic Resonance, Institute of Materials, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, P. R. China.

The jamming transition and jammed packing structures of hydrogel soft ellipsoids are studied using magnetic resonance imaging techniques. As the packing fraction increases, the fluctuation of local free volume decreases and the fluctuation of particle deformation increases. Effective thermodynamic quantities are obtained by characterizing these fluctuations using k-gamma distributions based on an underlying statistical model for granular materials. Surprisingly, the two granular temperatures measuring the relative fluctuations of both free volume and particle deformation remain basically unchanged as the packing fraction increases. The total configurational entropy is also approximately constant for packing with different packing fractions. The significantly different behaviors of these effective thermodynamic quantities compared with hard sphere systems are further attributed to a statistically affine structural transformation of the packing structures along with particle deformations when the packing fraction changes.
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http://dx.doi.org/10.1039/d0sm01699cDOI Listing
March 2021

Baicalin Inhibits Influenza A Virus Infection Promotion of M1 Macrophage Polarization.

Front Pharmacol 2020 6;11:01298. Epub 2020 Oct 6.

Department of Biological Medicines & Shanghai Engineering Research Center of Immunotherapeutics, Fudan University School of Pharmacy, Shanghai, China.

Background And Aims: The natural compound baicalin (BA) possesses potent antiviral properties against the influenza virus. However, the underlying molecular mechanisms of this antiviral activity and whether macrophages are involved remain unclear. In this study, we, therefore, investigated the effect of BA on macrophages.

Methods: We studied macrophage recruitment, functional phenotypes (M1/M2), and the cellular metabolism flow cytometry, qRT-PCR, immunofluorescence, a cell culture transwell system, and GC-MS-based metabolomics both in H1N1 A virus-infected mice and .

Results: BA treatment drastically reduced macrophage recruitment (CD11b, F4/80) by approximately 90% while maintaining the proportion of M1-polarized macrophages in the bronchoalveolar lavage fluid of infected mice. This BA-stimulated macrophage M1 phenotype shift was further verified in ANA-1 and primary peritoneal macrophages by measuring macrophage M1 polarization signals (CD86, iNOS, TNF-α, ratio, and IL-1β cleavage). Meanwhile, we observed an activation of the IFN pathway (upregulation of and ), an inhibition of influenza virus replication (as measured by the gene), and distinct cellular metabolic responses in BA-treated cells.

Conclusion: BA triggered macrophage M1 polarization, IFN activation, and other cellular reactions, which are beneficial for inhibition of H1N1 A virus infection.
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http://dx.doi.org/10.3389/fphar.2020.01298DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7574031PMC
October 2020

Baicalin down-regulating hepatitis B virus transcription depends on the liver-specific HNF4α-HNF1α axis.

Toxicol Appl Pharmacol 2020 09 17;403:115131. Epub 2020 Jul 17.

Department of Biological Medicines & Shanghai Engineering Research Center of Immunotherapeutics, School of Pharmacy, Fudan University, Shanghai 201203, PR China. Electronic address:

Baicalin (BA) inhibits hepatitis B virus (HBV) RNAs production and reduces levels of the related hepatocyte nuclear factors (HNFs), although the underlying mechanism is unclear. In this study, we investigated the specific pathway by which BA regulates HBV transcription through the HBV-related HNFs. Following transfection of HepG2 cells with pHBV1.2, we observed that BA inhibited the production of HBV RNAs and viral proteins in a time- and dose-dependent manner. These effects were consistent with the downregulation of HNF1α, which was abolished by HNF1α-shRNA. The shRNA of HNF4α, the upstream gene of HNF1α, also remarkedly reduced HNF1α expression and impaired the anti-HBV efficacy of BA, indicating that this function of BA depended on HNF4α/HNF1α axis. Furthermore, chromatin immunoprecipitation assay showed that BA significantly reduced HNF4α-HNF1α transactivation activity. The similar effects of BA were observed in entecavir (ETV)-resistant HBV transfected HepG2 cells. Thus, we proposed a mechanism for the anti-HBV activity of BA in an HNF4α-HNF1α-dependent manner, which impaired HNF4α and HNF1α transactivation, and effectively inhibited HBV transcription and viral replication.
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http://dx.doi.org/10.1016/j.taap.2020.115131DOI Listing
September 2020

Structural and topological nature of plasticity in sheared granular materials.

Nat Commun 2018 07 25;9(1):2911. Epub 2018 Jul 25.

School of Physics and Astronomy, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai, 200240, China.

Upon mechanical loading, granular materials yield and undergo plastic deformation. The nature of plastic deformation is essential for the development of the macroscopic constitutive models and the understanding of shear band formation. However, we still do not fully understand the microscopic nature of plastic deformation in disordered granular materials. Here we used synchrotron X-ray tomography technique to track the structural evolutions of three-dimensional granular materials under shear. We establish that highly distorted coplanar tetrahedra are the structural defects responsible for microscopic plasticity in disordered granular packings. The elementary plastic events occur through flip events which correspond to a neighbor switching process among these coplanar tetrahedra (or equivalently as the rotation motion of 4-ring disclinations). These events are discrete in space and possess specific orientations with the principal stress direction.
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http://dx.doi.org/10.1038/s41467-018-05329-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6060108PMC
July 2018

Translational and Rotational Dynamical Heterogeneities in Granular Systems.

Phys Rev Lett 2018 Jul;121(1):018002

School of Physics and Astronomy, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai 200240, China.

We use x-ray tomography to investigate the translational and rotational dynamical heterogeneities of a three dimensional hard ellipsoid granular packing driven by oscillatory shear. We find that particles which translate quickly form clusters with a size distribution given by a power law with an exponent that is independent of the strain amplitude. Identical behavior is found for particles that are translating slowly, rotating quickly, or rotating slowly. The geometrical properties of these four different types of clusters are the same as those of random clusters. Different cluster types are considerably correlated or anticorrelated, indicating a significant coupling between translational and rotational degrees of freedom. Surprisingly, these clusters are formed already at time scales that are much shorter than the α-relaxation time, in stark contrast to the behavior found in glass-forming systems.
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http://dx.doi.org/10.1103/PhysRevLett.121.018002DOI Listing
July 2018

Granular materials flow like complex fluids.

Nature 2017 11 1;551(7680):360-363. Epub 2017 Nov 1.

School of Physics and Astronomy, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai 200240, China.

Granular materials such as sand, powders and foams are ubiquitous in daily life and in industrial and geotechnical applications. These disordered systems form stable structures when unperturbed, but in the presence of external influences such as tapping or shear they 'relax', becoming fluid in nature. It is often assumed that the relaxation dynamics of granular systems is similar to that of thermal glass-forming systems. However, so far it has not been possible to determine experimentally the dynamic properties of three-dimensional granular systems at the particle level. This lack of experimental data, combined with the fact that the motion of granular particles involves friction (whereas the motion of particles in thermal glass-forming systems does not), means that an accurate description of the relaxation dynamics of granular materials is lacking. Here we use X-ray tomography to determine the microscale relaxation dynamics of hard granular ellipsoids subject to an oscillatory shear. We find that the distribution of the displacements of the ellipsoids is well described by a Gumbel law (which is similar to a Gaussian distribution for small displacements but has a heavier tail for larger displacements), with a shape parameter that is independent of the amplitude of the shear strain and of the time. Despite this universality, the mean squared displacement of an individual ellipsoid follows a power law as a function of time, with an exponent that does depend on the strain amplitude and time. We argue that these results are related to microscale relaxation mechanisms that involve friction and memory effects (whereby the motion of an ellipsoid at a given point in time depends on its previous motion). Our observations demonstrate that, at the particle level, the dynamic behaviour of granular systems is qualitatively different from that of thermal glass-forming systems, and is instead more similar to that of complex fluids. We conclude that granular materials can relax even when the driving strain is weak.
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http://dx.doi.org/10.1038/nature24062DOI Listing
November 2017

Origin of Noncubic Scaling Law in Disordered Granular Packing.

Phys Rev Lett 2017 Jun 9;118(23):238002. Epub 2017 Jun 9.

Department of Physics and Astronomy, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai 200240, China.

Recent diffraction experiments on metallic glasses have unveiled an unexpected noncubic scaling law between density and average interatomic distance, which led to the speculation of the presence of fractal glass order. Using x-ray tomography we identify here a similar noncubic scaling law in disordered granular packing of spherical particles. We find that the scaling law is directly related to the contact neighbors within the first nearest neighbor shell, and, therefore, is closely connected to the phenomenon of jamming. The seemingly universal scaling exponent around 2.5 arises due to the isostatic condition with a contact number around 6, and we argue that the exponent should not be universal.
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http://dx.doi.org/10.1103/PhysRevLett.118.238002DOI Listing
June 2017

The structural origin of the hard-sphere glass transition in granular packing.

Nat Commun 2015 Sep 28;6:8409. Epub 2015 Sep 28.

Department of Physics and Astronomy, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai 200240, China.

Glass transition is accompanied by a rapid growth of the structural relaxation time and a concomitant decrease of configurational entropy. It remains unclear whether the transition has a thermodynamic origin, and whether the dynamic arrest is associated with the growth of a certain static order. Using granular packing as a model hard-sphere glass, we show the glass transition as a thermodynamic phase transition with a 'hidden' polytetrahedral order. This polytetrahedral order is spatially correlated with the slow dynamics. It is geometrically frustrated and has a peculiar fractal dimension. Additionally, as the packing fraction increases, its growth follows an entropy-driven nucleation process, similar to that of the random first-order transition theory. Our study essentially identifies a long-sought-after structural glass order in hard-sphere glasses.
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http://dx.doi.org/10.1038/ncomms9409DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4598628PMC
September 2015

Angularly anisotropic correlation in granular packings.

Phys Rev E Stat Nonlin Soft Matter Phys 2014 Dec 1;90(6):062201. Epub 2014 Dec 1.

Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, USA.

We present an x-ray microtomography study of the three-dimensional structural correlations in monodisperse granular packings. By measuring an orientation-dependent pair correlation function, we find that the local structure shows an angularly anisotropic orientation correlation. The correlation is strongest along the major axis of the local Minkowski tensor of the Voronoi cell. It turns out that this anisotropic correlation is consistent with the existence of some locally favored structures. The study suggests the importance of high-order structural correlations in random granular packings.
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http://dx.doi.org/10.1103/PhysRevE.90.062201DOI Listing
December 2014

Similarity of wet granular packing to gels.

Nat Commun 2014 Sep 23;5:5014. Epub 2014 Sep 23.

Department of Physics and Astronomy, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai 200240, China.

To date, there is still no general consensus on the fundamental principle that governs glass transition. Colloidal suspensions are ordinarily utilized as model systems to study the dynamical arrest mechanisms in glass or gels. Here, we tackle the problem using athermal granular particles. Slow dynamics and structural evolution of granular packing upon tapping are monitored by fast X-ray tomography. When the packing are wet and short-range attractive interactions exist, we find a large amount of locally favoured structures with fivefold symmetry, which bear great structural similarity to colloidal gels. In addition, these structures are almost absent in dry packing with similar packing fractions. The study leads strong support for the geometrical frustration mechanism for dynamic arrest in both thermal and athermal systems with attractive interactions. It also suggests nontrivial structural mechanism, if exists, for dynamic arrest in systems with purely repulsive interactions.
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http://dx.doi.org/10.1038/ncomms6014DOI Listing
September 2014

X-ray tomography study of the random packing structure of ellipsoids.

Soft Matter 2014 Feb;10(7):990-6

We present an X-ray tomography study for the random packing of ellipsoids. The local structure displays short-range correlations. In addition to the contact number Z, we introduce ρshell, the average contact radius of curvature for contacting neighbors, as an additional parameter to characterize the local orientational geometry. In general, the local free volume w is affected by both Z and ρshell. We believe that the particle asphericity induces a polydispersity effect to influence the packing properties. A model is introduced which explicitly maps the ellipsoid packing onto a polydispersed sphere one, and it reproduces most of the experimental observations.
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http://dx.doi.org/10.1039/c3sm52841cDOI Listing
February 2014