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- He, Xingkang, et al.
(författare)
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Visualization of human T lymphocyte-mediated eradication of cancer cells in vivo
- 2020
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : NATL ACAD SCIENCES. - 0027-8424 .- 1091-6490. ; 117:37, s. 22910-22919
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Tidskriftsartikel (refereegranskat)abstract
- Lymphocyte-based immunotherapy has emerged as a break-through in cancer therapy for both hematologic and solid malignancies. In a subpopulation of cancer patients, this powerful therapeutic modality converts malignancy to clinically manageable disease. However, the T cell- and chimeric antigen receptor T (CAR-T) cell-mediated antimetastatic activity, especially their impacts on microscopic metastatic lesions, has not yet been investigated. Here we report a living zebrafish model that allows us to visualize the metastatic cancer cell killing effect by tumor- infiltrating lymphocytes (TILs) and CAR-T cells in vivo at the single-cell level. In a freshly isolated primary human melanoma, specific TILs effectively eliminated metastatic cancer cells in the living body. This potent metastasis-eradicating effect was validated using a human lymphoma model with CAR-T cells. Furthermore, cancer-associated fibroblasts protected metastatic cancer cells from T cell-mediated killing. Our data provide an in vivo platform to validate antimetastatic effects by human T cell-mediated immunotherapy. This unique technology may serve as a precision medicine platform for assessing anticancer effects of cellular immunotherapy in vivo before administration to human cancer patients.
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- Huang, Zhen, et al.
(författare)
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Recurrent chromosome reshuffling and the evolution of neo-sex chromosomes in parrots
- 2022
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Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- Parrots have undergone substantial karyotype evolution compared to most other birds. Here, Huang et al. analyze chromosome-level genome assemblies for four parrot species and elucidate the complex evolutionary history of parrot chromosomes. The karyotype of most birds has remained considerably stable during more than 100 million years' evolution, except for some groups, such as parrots. The evolutionary processes and underlying genetic mechanism of chromosomal rearrangements in parrots, however, are poorly understood. Here, using chromosome-level assemblies of four parrot genomes, we uncover frequent chromosome fusions and fissions, with most of them occurring independently among lineages. The increased activities of chromosomal rearrangements in parrots are likely associated with parrot-specific loss of two genes, ALC1 and PARP3, that have known functions in the repair of double-strand breaks and maintenance of genome stability. We further find that the fusion of the ZW sex chromosomes and chromosome 11 has created a pair of neo-sex chromosomes in the ancestor of parrots, and the chromosome 25 has been further added to the sex chromosomes in monk parakeet. Together, the combination of our genomic and cytogenetic analyses characterizes the complex evolutionary history of chromosomal rearrangements and sex chromosomes in parrots.
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- Law, Chi Yan, 1990, et al.
(författare)
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Polarized Light from Massive Protoclusters (POLIMAP). I. Dissecting the Role of Magnetic Fields in the Massive Infrared Dark Cloud G28.37+0.07
- 2024
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Ingår i: Astrophysical Journal. - 1538-4357 .- 0004-637X. ; 967:2
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Tidskriftsartikel (refereegranskat)abstract
- Magnetic fields may play a crucial role in setting the initial conditions of massive star and star cluster formation. To investigate this, we report SOFIA-HAWC+ 214 μm observations of polarized thermal dust emission and high-resolution GBT-Argus C18O(1-0) observations toward the massive Infrared Dark Cloud (IRDC) G28.37+0.07. Considering the local dispersion of B-field orientations, we produce a map of the B-field strength of the IRDC, which exhibits values between ∼0.03 and 1 mG based on a refined Davis-Chandrasekhar-Fermi method proposed by Skalidis & Tassis. Comparing to a map of inferred density, the IRDC exhibits a B-n relation with a power-law index of 0.51 ± 0.02, which is consistent with a scenario of magnetically regulated anisotropic collapse. Consideration of the mass-to-flux ratio map indicates that magnetic fields are dynamically important in most regions of the IRDC. A virial analysis of a sample of massive, dense cores in the IRDC, including evaluation of magnetic and kinetic internal and surface terms, indicates consistency with virial equilibrium, sub-Alfvénic conditions, and a dominant role for B-fields in regulating collapse. A clear alignment of magnetic field morphology with the direction of the steepest column density gradient is also detected. However, there is no preferred orientation of protostellar outflow directions with the B-field. Overall, these results indicate that magnetic fields play a crucial role in regulating massive star and star cluster formation, and therefore they need to be accounted for in theoretical models of these processes.
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- Lu, Shen-ning, et al.
(författare)
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Application of an innovative grid-based surveillance strategy to ensure elimination and prevent reintroduction of malaria in high-risk border communities in China
- 2022
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Ingår i: BMC Public Health. - : Springer Nature. - 1471-2458. ; 22:1
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Tidskriftsartikel (refereegranskat)abstract
- Grid management is a grassroots governance strategy widely implemented in China since 2004 to improve the government's efficiency to actively find and solve problems among populated regions. A grid-based strategy surveillancing high-risk groups, including mobile and migrant populations (MMPs), in the China-Myanmar border region has played an indispensable role in promoting and consolidating the malaria elimination efforts by tracking and timely identification of potential importation or re-establishment of malaria among MMPs. A sequential mixed methods was implementated to explore the operational mechanism and best practices of the grid-based strategy including through the focus group discussions (FGDs), comparison of before and after the implementation of a grid-based strategy in the field sites, and data collection from the local health system.This paper distills the implementation mechanism and highlights the role of the grid-based strategy in the elimination and prevention of re-establishment of malaria transmission.
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- Wu, Duo, et al.
(författare)
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From starch to polylactide and nano-graphene oxide : fully starch derived high performance composites
- 2016
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Ingår i: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 6:59, s. 54336-54345
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Tidskriftsartikel (refereegranskat)abstract
- A delicate closed-loop strategy for valorization of starch to value-added products was developed. Carbon sheets, formed of carbon spheres, were obtained by microwave-assisted hydrothermal degradation of starch and then further transformed into nano-sized graphene oxide (nGO, 20 x 30 nm(2)) under oxygen-rich acidic conditions. The synthesized nGO exhibited self-assembly in solution. Furthermore, nGO strongly attached to the surface of starch granules by hydrogen bonding (nGO@ starch, 0.1 wt%) and allowed easy and highly efficient interfacial engineering in PLA/starch composites. After combining with polylactide (PLA), the composites could incorporate up to 30 wt% nGO@ starch, while retaining excellent properties. nGO was capable of facilitating PLA crystallization in the composites by providing a number of nucleation sites. Moreover, the interfacial adhesion between PLA and starch was significantly improved by nGO. Though its content was extremely low, nGO improved the mechanical and barrier properties and thermal stability of the PLA/starch composites. The results demonstrate a facile route to value-added starch-derived nGO and further to fully starch derived high performance PLA/starch biocomposites.
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- Xu, Duo, et al.
(författare)
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A Census of Outflow to Magnetic Field Orientations in Nearby Molecular Clouds
- 2022
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 1538-4357 .- 0004-637X. ; 941:1
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Tidskriftsartikel (refereegranskat)abstract
- We define a sample of 200 protostellar outflows showing blue- and redshifted CO emission in the nearby molecular clouds Ophiuchus, Taurus, Perseus, and Orion, to investigate the correlation between outflow orientations and local, but relatively large-scale, magnetic field directions traced by Planck 353 GHz dust polarization. At high significance (p ∼ 10−4), we exclude a random distribution of relative orientations and find that there is a preference for alignment of projected plane of sky outflow axes with magnetic field directions. The distribution of relative position angles peaks at ∼30° and exhibits a broad dispersion of ∼50°. These results indicate that magnetic fields have dynamical influence in regulating the launching and/or propagation directions of outflows. However, the significant dispersion around perfect alignment orientation implies that there are large measurement uncertainties and/or a high degree of intrinsic variation caused by other physical processes, such as turbulence or strong stellar dynamical interactions. Outflow to magnetic field alignment is expected to lead to a correlation in the directions of nearby outflow pairs, depending on the degree of order of the field. Analyzing this effect, we find limited correlation, except on relatively small scales ≲0.5 pc. Furthermore, we train a convolutional neural network to infer the inclination angle of outflows with respect to the line of sight and apply it to our outflow sample to estimate their full 3D orientations. We find that the angles between outflow pairs in 3D space also show evidence of small-scale alignment.
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- Xu, Duo, et al.
(författare)
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Application of Convolutional Neural Networks to Predict Magnetic Fields’ Directions in Turbulent Clouds
- 2023
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 1538-4357 .- 0004-637X. ; 942:2
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Tidskriftsartikel (refereegranskat)abstract
- We adopt the deep learning method casi-3d (convolutional approach to structure identification-3D) to infer the orientation of magnetic fields in sub-/trans-Alfvénic turbulent clouds from molecular line emission. We carry out magnetohydrodynamic simulations with different magnetic field strengths and use these to generate synthetic observations. We apply the 3D radiation transfer code radmc-3d to model 12CO and 13CO (J = 1−0) line emission from the simulated clouds and then train a casi-3d model on these line emission data cubes to predict magnetic field morphology at the pixel level. The trained casi-3d model is able to infer magnetic field directions with a low error (≲10° for sub-Alfvénic samples and ≲30° for trans-Alfvénic samples). We further test the performance of casi-3d on a real sub-/trans- Alfvénic region in Taurus. The casi-3d prediction is consistent with the magnetic field direction inferred from Planck dust polarization measurements. We use our developed methods to produce a new magnetic field map of Taurus that has a three times higher angular resolution than the Planck map.
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- Xu, Duo, et al.
(författare)
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Denoising Diffusion Probabilistic Models to Predict the Density of Molecular Clouds
- 2023
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Ingår i: Astrophysical Journal. - 1538-4357 .- 0004-637X. ; 950:2
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Tidskriftsartikel (refereegranskat)abstract
- We introduce the state-of-the-art deep-learning denoising diffusion probabilistic model as a method to infer the volume or number density of giant molecular clouds (GMCs) from projected mass surface density maps. We adopt magnetohydrodynamic simulations with different global magnetic field strengths and large-scale dynamics, i.e., noncolliding and colliding GMCs. We train a diffusion model on both mass surface density maps and their corresponding mass-weighted number density maps from different viewing angles for all the simulations. We compare the diffusion model performance with a more traditional empirical two-component and three-component power-law fitting method and with a more traditional neural network machine-learning approach. We conclude that the diffusion model achieves an order-of-magnitude improvement on the accuracy of predicting number density compared to that by other methods. We apply the diffusion method to some example astronomical column density maps of Taurus and the infrared dark clouds G28.37+0.07 and G35.39-0.33 to produce maps of their mean volume densities.
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- Xu, Duo, et al.
(författare)
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Disk Wind Feedback from High-mass Protostars. III. Synthetic CO Line Emission
- 2024
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Ingår i: Astrophysical Journal. - 1538-4357 .- 0004-637X. ; 966:1
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Tidskriftsartikel (refereegranskat)abstract
- To test theoretical models of massive star formation it is important to compare their predictions with observed systems. To this end, we conduct CO molecular line radiative transfer post-processing of 3D magnetohydrodynamic simulations of various stages in the evolutionary sequence of a massive protostellar core, including its infall envelope and disk wind outflow. Synthetic position-position-velocity cubes of various transitions of 12CO, 13CO, and C18O emission are generated. We also carry out simulated Atacama Large Millimeter/submillimeter Array (ALMA) observations of this emission. We compare the mass, momentum, and kinetic energy estimates obtained from molecular lines to the true values, finding that the mass and momentum estimates can have uncertainties of up to a factor of 4. However, the kinetic energy estimated from molecular lines is more significantly underestimated. Additionally, we compare the mass outflow rate and momentum outflow rate obtained from the synthetic spectra with the true values. Finally, we compare the synthetic spectra with real examples of ALMA-observed protostars and determine the best-fitting protostellar masses and outflow inclination angles. We then calculate the mass outflow rate and momentum outflow rate for these sources, finding that both rates agree with theoretical protostellar evolutionary tracks.
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- Xu, Huan, et al.
(författare)
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Immobilized Graphene Oxide Nanosheets as Thin but Strong Nanointerfaces in Biocomposites
- 2016
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Ingår i: ACS Sustainable Chemistry and Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 4:4, s. 2211-2222
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Tidskriftsartikel (refereegranskat)abstract
- Graphene oxide (GO) nanosheets featuring high surface activity and large planar dimension may function as robust nanointerfaces in biocomposites, contributing to simultaneous promotion of mechanical and gas barrier properties. Here, a solution-processed, additive-free approach to immobilize few-layer GO nanosheets on starch granule surfaces (GO@starch) by hydrogen bonding is demonstrated. This approach enabled a straightforward pathway to remove the intersheet van der Waals forces (pi-pi stacking) that generally cause reaggregation and poor dispersion of GO in polymer matrices. Incorporation of GO@starch into poly (lactic acid) (PLA) allowed an interesting structure with few-layer nanosheets firmly immobilized at the PLA-starch interfaces. Inheriting the high aspect ratio and surface energy of GO, GO@starch distinctly strengthened the interfacial interactions with PLA, albeit present at ultralow GO concentrations (up to 0.03 wt %), facilitating the dispersion of GO@starch and nucleation of PLA. The morphological regulation rendered composite films with an impressive combination of high thermal stability, mechanical strength and oxygen resistance. A substantial increase of 280% in tensile strength (58.2 MPa) and a prominent decline of 82% in oxygen permeation coefficient (4.0 cm(3) mm cm(-2) day(-1) atm(-1)) were achieved in the composites loaded with 30 wt % GO@starch in comparison with the counterpart. The cost-performance ratio for the nanostructured biocomposites was excellent even compared to the established packaging materials. The multiscale morphological regulation of sheet-like nanofillers by controlled exfoliation and immobilization of GO on microsized starch particle surfaces, the simplicity of manufacturing, together with the versatility of the engineered composites should make our strategy broadly applicable to other material combinations.
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- Xu, Huan, et al.
(författare)
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Thermostable and impermeable "nano-barrier walls" constructed by poly(lactic acid) stereocomplex crystal decorated graphene oxide nanosheets
- 2015
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Ingår i: Macromolecules. - : American Chemical Society (ACS). - 0024-9297 .- 1520-5835. ; 48:7, s. 2127-2137
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Tidskriftsartikel (refereegranskat)abstract
- In contrast to the relatively clear understanding of epitaxial crystallization induced by one-dimensional nanofillers, the underlying interfacial interactions between polymer crystals and two-dimensional graphene oxide (GO) nanosheets are something of a mystery. Here, the GO-assisted formation of poly(lactic acid) (PLA) stereocomplex crystals (SCs) is disclosed from the quantitative structural analysis to the direct morphological observations at multiscale and the interaction mechanism at the molecular level. It is unexpected to observe that the edges of GO featuring rich grooves and ultralow thickness were ready to induce a layer of ordered lamellae, in clear contrast to the random growth of lamellae on the basal planes. The origin of GO-induced crystallization was appraised from the interaction point of view as indicated by the evident red-shift of a set of functional groups in the Fourier transform infrared spectroscopy spectra. More importantly, the GO nanosheets, albeit presented at an extremely low content (0.05 wt %), decorated by the preferred formation of SCs enabled the simultaneous enhancement of gas barrier properties and resistance to heat distortion. Specifically, the unique combination of greatly improved heat deformation temperature (HDT) and low oxygen permeability coefficient (PO2) for the composite crystallized at 165 °C was demonstrated (146.5 °C and 0.95 × 10-15 cm3 cm cm-2 s-1 Pa-1), outperforming pure PLA with an increment of 75% and a decrease of 77% in HDT and PO2, respectively. The proposed methodology affords elucidation of well-tailored thermal and barrier properties, which may motivate further extension of this rational design to other material combinations.
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