| 1. |
- Beal, Jacob, et al.
(author)
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Robust estimation of bacterial cell count from optical density
- 2020
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In: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
-
Journal article (peer-reviewed)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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| 2. |
- Fenstermacher, M.E., et al.
(author)
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DIII-D research advancing the physics basis for optimizing the tokamak approach to fusion energy
- 2022
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In: Nuclear Fusion. - : IOP Publishing. - 0029-5515 .- 1741-4326. ; 62:4
-
Journal article (peer-reviewed)abstract
- DIII-D physics research addresses critical challenges for the operation of ITER and the next generation of fusion energy devices. This is done through a focus on innovations to provide solutions for high performance long pulse operation, coupled with fundamental plasma physics understanding and model validation, to drive scenario development by integrating high performance core and boundary plasmas. Substantial increases in off-axis current drive efficiency from an innovative top launch system for EC power, and in pressure broadening for Alfven eigenmode control from a co-/counter-I p steerable off-axis neutral beam, all improve the prospects for optimization of future long pulse/steady state high performance tokamak operation. Fundamental studies into the modes that drive the evolution of the pedestal pressure profile and electron vs ion heat flux validate predictive models of pedestal recovery after ELMs. Understanding the physics mechanisms of ELM control and density pumpout by 3D magnetic perturbation fields leads to confident predictions for ITER and future devices. Validated modeling of high-Z shattered pellet injection for disruption mitigation, runaway electron dissipation, and techniques for disruption prediction and avoidance including machine learning, give confidence in handling disruptivity for future devices. For the non-nuclear phase of ITER, two actuators are identified to lower the L-H threshold power in hydrogen plasmas. With this physics understanding and suite of capabilities, a high poloidal beta optimized-core scenario with an internal transport barrier that projects nearly to Q = 10 in ITER at ∼8 MA was coupled to a detached divertor, and a near super H-mode optimized-pedestal scenario with co-I p beam injection was coupled to a radiative divertor. The hybrid core scenario was achieved directly, without the need for anomalous current diffusion, using off-axis current drive actuators. Also, a controller to assess proximity to stability limits and regulate β N in the ITER baseline scenario, based on plasma response to probing 3D fields, was demonstrated. Finally, innovative tokamak operation using a negative triangularity shape showed many attractive features for future pilot plant operation.
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| 3. |
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| 4. |
- Arzoumanian, Doris, et al.
(author)
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Dust polarized emission observations of NGC 6334: BISTRO reveals the details of the complex but organized magnetic field structure of the high-mass star-forming hub-filament network
- 2021
-
In: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 647
-
Journal article (peer-reviewed)abstract
- Context. Molecular filaments and hubs have received special attention recently thanks to new studies showing their key role in star formation. While the (column) density and velocity structures of both filaments and hubs have been carefully studied, their magnetic field (B-field) properties have yet to be characterized. Consequently, the role of B-fields in the formation and evolution of hub-filament systems is not well constrained. Aims. We aim to understand the role of the B-field and its interplay with turbulence and gravity in the dynamical evolution of the NGC 6334 filament network that harbours cluster-forming hubs and high-mass star formation. Methods. We present new observations of the dust polarized emission at 850 μm toward the 2 pc × 10 pc map of NGC 6334 at a spatial resolution of 0.09 pc obtained with the James Clerk Maxwell Telescope (JCMT) as part of the B-field In STar-forming Region Observations (BISTRO) survey. We study the distribution and dispersion of the polarized intensity (PI), the polarization fraction (PF), and the plane-of-The-sky B-field angle (χB_POS) toward the whole region, along the 10 pc-long ridge and along the sub-filaments connected to the ridge and the hubs. We derived the power spectra of the intensity and χBPOS along the ridge crest and compared them with the results obtained from simulated filaments. Results. The observations span 3 orders of magnitude in Stokes I and PI and 2 orders of magnitude in PF (from 0.2 to 20%). A large scatter in PI and PF is observed for a given value of I. Our analyses show a complex B-field structure when observed over the whole region ( 10 pc); however, at smaller scales (1 pc), χBPOS varies coherently along the crests of the filament network. The observed power spectrum of χBPOS can be well represented with a power law function with a slope of-1.33 ± 0.23, which is 20% shallower than that of I. We find that this result is compatible with the properties of simulated filaments and may indicate the physical processes at play in the formation and evolution of star-forming filaments. Along the sub-filaments, χBPOS rotates frombeing mostly perpendicular or randomly oriented with respect to the crests to mostly parallel as the sub-filaments merge with the ridge and hubs. This variation of the B-field structure along the sub-filaments may be tracing local velocity flows of infalling matter in the ridge and hubs. Our analysis also suggests a variation in the energy balance along the crests of these sub-filaments, from magnetically critical or supercritical at their far ends to magnetically subcritical near the ridge and hubs. We also detect an increase in PF toward the high-column density (NH2 â 1023 cm-2) star cluster-forming hubs. These latter large PF values may be explained by the increase in grain alignment efficiency due to stellar radiation from the newborn stars, combined with an ordered B-field structure. Conclusions. These observational results reveal for the first time the characteristics of the small-scale (down to 0.1 pc) B-field structure of a 10 pc-long hub-filament system. Our analyses show variations in the polarization properties along the sub-filaments that may be tracing the evolution of their physical properties during their interaction with the ridge and hubs. We also detect an impact of feedback from young high-mass stars on the local B-field structure and the polarization properties, which could put constraints on possible models for dust grain alignment and provide important hints as to the interplay between the star formation activity and interstellar B-fields.
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| 5. |
- Ching, Tao-Chung, et al.
(author)
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The JCMT BISTRO-2 Survey: Magnetic Fields of the Massive DR21 Filament
- 2022
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In: Astrophysical Journal. - : American Astronomical Society. - 1538-4357 .- 0004-637X. ; 941:2
-
Journal article (peer-reviewed)abstract
- We present 850 mu m dust polarization observations of the massive DR21 filament from the B-fields In STar-forming Region Observations (BISTRO) survey, using the POL-2 polarimeter and the SCUBA-2 camera on the James Clerk Maxwell Telescope. We detect ordered magnetic fields perpendicular to the parsec-scale ridge of the DR21 main filament. In the subfilaments, the magnetic fields are mainly parallel to the filamentary structures and smoothly connect to the magnetic fields of the main filament. We compare the POL-2 and Planck dust polarization observations to study the magnetic field structures of the DR21 filament on 0.1-10 pc scales. The magnetic fields revealed in the Planck data are well-aligned with those of the POL-2 data, indicating a smooth variation of magnetic fields from large to small scales. The plane-of-sky magnetic field strengths derived from angular dispersion functions of dust polarization are 0.6-1.0 mG in the DR21 filament and similar to 0.1 mG in the surrounding ambient gas. The mass-to-flux ratios are found to be magnetically supercritical in the filament and slightly subcritical to nearly critical in the ambient gas. The alignment between column density structures and magnetic fields changes from random alignment in the low-density ambient gas probed by Planck to mostly perpendicular in the high-density main filament probed by James Clerk Maxwell Telescope. The magnetic field structures of the DR21 filament are in agreement with MHD simulations of a strongly magnetized medium, suggesting that magnetic fields play an important role in shaping the DR21 main filament and subfilaments.
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| 6. |
- Eswaraiah, Chakali, et al.
(author)
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The JCMT BISTRO Survey: Revealing the Diverse Magnetic Field Morphologies in Taurus Dense Cores with Sensitive Submillimeter Polarimetry
- 2021
-
In: Astrophysical Journal Letters. - : American Astronomical Society. - 2041-8213 .- 2041-8205. ; 912:2
-
Journal article (peer-reviewed)abstract
- We have obtained sensitive dust continuum polarization observations at 850 μm in the B213 region of Taurus using POL-2 on SCUBA-2 at the James Clerk Maxwell Telescope as part of the B-fields in STar-forming Region Observations (BISTRO) survey. These observations allow us to probe magnetic field (B-field) at high spatial resolution (∼2000 au or ∼0.01 pc at 140 pc) in two protostellar cores (K04166 and K04169) and one prestellar core (Miz-8b) that lie within the B213 filament. Using the Davis-Chandrasekhar-Fermi method, we estimate the B-field strengths in K04166, K04169, and Miz-8b to be 38 ± 14, 44 ± 16, and 12 ± 5 μG, respectively. These cores show distinct mean B-field orientations. The B-field in K04166 is well ordered and aligned parallel to the orientations of the core minor axis, outflows, core rotation axis, and large-scale uniform B-field, in accordance with magnetically regulated star formation via ambipolar diffusion taking place in K04166. The B-field in K04169 is found to be ordered but oriented nearly perpendicular to the core minor axis and large-scale B-field and not well correlated with other axes. In contrast, Miz-8b exhibits a disordered B-field that shows no preferred alignment with the core minor axis or large-scale field. We found that only one core, K04166, retains a memory of the large-scale uniform B-field. The other two cores, K04169 and Miz-8b, are decoupled from the large-scale field. Such a complex B-field configuration could be caused by gas inflow onto the filament, even in the presence of a substantial magnetic flux.
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| 7. |
- Karoly, Janik, et al.
(author)
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The JCMT BISTRO Survey: Studying the Complex Magnetic Field of L43
- 2023
-
In: Astrophysical Journal. - 1538-4357 .- 0004-637X. ; 952:1
-
Journal article (peer-reviewed)abstract
- We present observations of polarized dust emission at 850 mu m from the L43 molecular cloud, which sits in the Ophiuchus cloud complex. The data were taken using SCUBA-2/POL-2 on the James Clerk Maxwell Telescope as a part of the BISTRO large program. L43 is a dense (N-H2 similar to 10(22) - 10(23) cm(-2)) complex molecular cloud with a submillimeter-bright starless core and two protostellar sources. There appears to be an evolutionary gradient along the isolated filament that L43 is embedded within, with the most evolved source closest to the Sco OB2 association. One of the protostars drives a CO outflow that has created a cavity to the southeast. We see a magnetic field that appears to be aligned with the cavity walls of the outflow, suggesting interaction with the outflow. We also find a magnetic field strength of up to similar to 160 +/- 30 mu G in the main starless core and up to similar to 90 +/- 40 mu G in the more diffuse, extended region. These field strengths give magnetically super- and subcritical values, respectively, and both are found to be roughly trans-Alfvenic. We also present a new method of data reduction for these denser but fainter objects like starless cores.
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| 8. |
- Kwon, Woojin, et al.
(author)
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B-fields in Star-forming Region Observations (BISTRO): Magnetic Fields in the Filamentary Structures of Serpens Main
- 2022
-
In: Astrophysical Journal. - : American Astronomical Society. - 1538-4357 .- 0004-637X. ; 926:2
-
Journal article (peer-reviewed)abstract
- We present 850 mu m polarimetric observations toward the Serpens Main molecular cloud obtained using the POL-2 polarimeter on the James Clerk Maxwell Telescope as part of the B-fields In STar-forming Region Observations survey. These observations probe the magnetic field morphology of the Serpens Main molecular cloud on about 6000 au scales, which consists of cores and six filaments with different physical properties such as density and star formation activity. Using the histogram of relative orientation (HRO) technique, we find that magnetic fields are parallel to filaments in less-dense filamentary structures where NH2 < 0.93 x 10(22) cm(-2) (magnetic fields perpendicular to density gradients), while they are perpendicular to filaments (magnetic fields parallel to density gradients) in dense filamentary structures with star formation activity. Moreover, applying the HRO technique to denser core regions, we find that magnetic field orientations change to become perpendicular to density gradients again at NH2 approximate to 4.6 x 10(22) NH2 approximate to 16 x 10(22) cm(-2), magnetic fields change back to being parallel to density gradients once again, which can be understood to be due to magnetic fields being dragged in by infalling material. In addition, we estimate the magnetic field strengths of the filaments (B-POS = 60-300 mu G)) using the Davis-Chandrasekhar-Fermi method and discuss whether the filaments are gravitationally unstable based on magnetic field and turbulence energy densities.
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| 9. |
- Liu, Tao, et al.
(author)
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16% efficiency all-polymer organic solar cells enabled by a finely tuned morphology via the design of ternary blend
- 2021
-
In: Joule. - : CELL PRESS. - 2542-4351. ; 5:4, s. 914-930
-
Journal article (peer-reviewed)abstract
- A SUMMARY There is an urgent demand for all-polymer organic solar cells (AP-OSCs) to gain higher efficiency. Here, we successfully improve the performance to 16.09% by introducing a small amount of BN-T, a B <- N-type polymer acceptor, into the PM6:PY-IT blend. It has been found that BN-T makes the active layer, based on the PM6:PY-IT:BN-T ternary blend, more crystalline but meanwhile slightly reduces the phase separation, leading to enhancement of both exciton harvesting and charge transport. From a thermodynamic viewpoint, BN-T prefers to reside between PM6 and PY-IT, and the fraction of this fine-tunes the morphology. Besides, a significantly reduced nonradiative energy loss occurs in the ternary blend, along with the coexistence of energy and charge transfer between the two acceptors. The progressive performance facilitated by these improved properties demonstrates that AP-OSCs can possibly comparably efficient with those based on small molecule acceptors, further enhancing the competitiveness of this device type.
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| 10. |
- Lyo, A-Ran, et al.
(author)
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The JCMT BISTRO Survey: An 850/450 mu m Polarization Study of NGC 2071IR in Orion B
- 2021
-
In: Astrophysical Journal. - : American Astronomical Society. - 1538-4357 .- 0004-637X. ; 918:2
-
Journal article (peer-reviewed)abstract
- We present the results of simultaneous 450 mu m and 850 mu m polarization observations toward the massive star-forming region NGC 2071IR, a target of the BISTRO (B-fields in STar-forming Region Observations) Survey, using the POL-2 polarimeter and SCUBA-2 camera mounted on the James Clerk Maxwell Telescope. We find a pinched magnetic field morphology in the central dense core region, which could be due to a rotating toroidal disklike structure and a bipolar outflow originating from the central young stellar object IRS 3. Using the modified Davis-Chandrasekhar-Fermi method, we obtain a plane-of-sky magnetic field strength of 563 +/- 421 mu G in the central similar to 0.12 pc region from 850 mu m polarization data. The corresponding magnetic energy density of 2.04 x 10(-8) erg cm(-3) is comparable to the turbulent and gravitational energy densities in the region. We find that the magnetic field direction is very well aligned with the whole of the IRS 3 bipolar outflow structure. We find that the median value of polarization fractions is 3.0% at 450 mu m in the central 3 ' region, which is larger than the median value of 1.2% at 850 mu m. The trend could be due to the better alignment of warmer dust in the strong radiation environment. We also find that polarization fractions decrease with intensity at both wavelengths, with slopes, determined by fitting a Rician noise model of 0.59 +/- 0.03 at 450 mu m and 0.36 +/- 0.04 at 850 mu m, respectively. We think that the shallow slope at 850 mu m is due to grain alignment at the center being assisted by strong radiation from the central young stellar objects.
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| 11. |
- Ngoc, Nguyen Bich, et al.
(author)
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Observations of Magnetic Fields Surrounding LkH alpha 101 Taken by the BISTRO Survey with JCMT-POL-2
- 2021
-
In: Astrophysical Journal. - : American Astronomical Society. - 1538-4357 .- 0004-637X. ; 908:1
-
Journal article (peer-reviewed)abstract
- We report the first high spatial resolution measurement of magnetic fields surrounding LkH alpha 101, part of the Auriga-California molecular cloud. The observations were taken with the POL-2 polarimeter on the James Clerk Maxwell Telescope within the framework of the B-fields In Star-forming Region Observations (BISTRO) survey. Observed polarization of thermal dust emission at 850 mu m is found to be mostly associated with the redshifted gas component of the cloud. The magnetic field displays a relatively complex morphology. Two variants of the Davis-Chandrasekhar-Fermi method, unsharp masking and structure function, are used to calculate the strength of magnetic fields in the plane of the sky, yielding a similar result of B-POS similar to 115 mu G. The mass-to-magnetic-flux ratio in critical value units, lambda similar to 0.3, is the smallest among the values obtained for other regions surveyed by POL-2. This implies that the LkH alpha 101 region is subcritical, and the magnetic field is strong enough to prevent gravitational collapse. The inferred delta B/B-0 similar to 0.3 implies that the large-scale component of the magnetic field dominates the turbulent one. The variation of the polarization fraction with total emission intensity can be fitted by a power law with an index of alpha = 0.82 0.03, which lies in the range previously reported for molecular clouds. We find that the polarization fraction decreases rapidly with proximity to the only early B star (LkH alpha 101) in the region. Magnetic field tangling and the joint effect of grain alignment and rotational disruption by radiative torques can potentially explain such a decreasing trend.
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| 12. |
- Tahani, Mehrnoosh, et al.
(author)
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JCMT BISTRO Observations: Magnetic Field Morphology of Bubbles Associated with NGC 6334
- 2023
-
In: Astrophysical Journal. - : American Astronomical Society. - 1538-4357 .- 0004-637X. ; 944:2
-
Journal article (peer-reviewed)abstract
- We study the Hii regions associated with the NGC 6334 molecular cloud observed in the submillimeter and taken as part of the B-fields In STar-forming Region Observations Survey. In particular, we investigate the polarization patterns and magnetic field morphologies associated with these Hii regions. Through polarization pattern and pressure calculation analyses, several of these bubbles indicate that the gas and magnetic field lines have been pushed away from the bubble, toward an almost tangential (to the bubble) magnetic field morphology. In the densest part of NGC 6334, where the magnetic field morphology is similar to an hourglass, the polarization observations do not exhibit observable impact from Hii regions. We detect two nested radial polarization patterns in a bubble to the south of NGC 6334 that correspond to the previously observed bipolar structure in this bubble. Finally, using the results of this study, we present steps (incorporating computer vision; circular Hough transform) that can be used in future studies to identify bubbles that have physically impacted magnetic field lines.
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| 13. |
- Chen, Zhiwei, et al.
(author)
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Cross-Device Radio Frequency Fingerprinting Identification Based on Domain Adaptation
- 2024
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In: IEEE transactions on consumer electronics. - : Institute of Electrical and Electronics Engineers (IEEE). - 0098-3063 .- 1558-4127. ; 70:1, s. 2391-2400
-
Journal article (peer-reviewed)abstract
- Radio frequency fingerprinting (RFF) is a lightweight authentication technology for resource-limited terminal nodes by exploiting the unique hardware imperfections resulting from the manufacturing process. Previous studies about radio frequency fingerprinting identification (RFFI) mainly concentrate on improving the accuracy which is evaluated by the single receiver device that trains and identifies all the nodes. Due to the mobility of the consumer electronic terminals, these terminal nodes may need to be identified by the different receivers. In this paper, we propose a cross-device radio frequency fingerprinting identification scheme which allows enrolled nodes to be authenticated by different devices. Motivated by the observation that signals collected by different receiver devices have a distribution shift that would violate the basic independent and identically distributed (i.i.d) assumption of supervised learning. Domain adaptation is adopted to improve the accuracy under different receivers, which can align the data captured from different devices and eliminate the distribution shift through the labeled data from one receiver device and unlabeled data from the other device. By this way, the distribution shift from different devices is corrected. Extensive experiment configurations under various Signal-to-noise ratio (SNR) are carried out to demonstrate the performance of domain adaptation with the same model structure. The results indicate that classification accuracy under different devices can be increased by 7%-15% and get a stable accuracy rate higher than 90% by leveraging our proposed cross-device RFFI scheme.
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| 14. |
- Chen, Zhishan, et al.
(author)
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Fine-mapping analysis including over 254 000 East Asian and European descendants identifies 136 putative colorectal cancer susceptibility genes
- 2024
-
In: Nature Communications. - : Springer Nature. - 2041-1723. ; 15:1
-
Journal article (peer-reviewed)abstract
- Genome-wide association studies (GWAS) have identified more than 200 common genetic variants independently associated with colorectal cancer (CRC) risk, but the causal variants and target genes are mostly unknown. We sought to fine-map all known CRC risk loci using GWAS data from 100,204 cases and 154,587 controls of East Asian and European ancestry. Our stepwise conditional analyses revealed 238 independent association signals of CRC risk, each with a set of credible causal variants (CCVs), of which 28 signals had a single CCV. Our cis-eQTL/mQTL and colocalization analyses using colorectal tissue-specific transcriptome and methylome data separately from 1299 and 321 individuals, along with functional genomic investigation, uncovered 136 putative CRC susceptibility genes, including 56 genes not previously reported. Analyses of single-cell RNA-seq data from colorectal tissues revealed 17 putative CRC susceptibility genes with distinct expression patterns in specific cell types. Analyses of whole exome sequencing data provided additional support for several target genes identified in this study as CRC susceptibility genes. Enrichment analyses of the 136 genes uncover pathways not previously linked to CRC risk. Our study substantially expanded association signals for CRC and provided additional insight into the biological mechanisms underlying CRC development.
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| 15. |
- Doi, Yasuo, et al.
(author)
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The JCMT BISTRO Survey: Magnetic Fields Associated with a Network of Filaments in NGC 1333
- 2020
-
In: Astrophysical Journal. - : American Astronomical Society. - 1538-4357 .- 0004-637X. ; 899:1
-
Journal article (peer-reviewed)abstract
- We present new observations of the active star formation region NGC 1333 in the Perseus molecular cloud complex from the James Clerk Maxwell Telescope B-Fields In Star-forming Region Observations (BISTRO) survey with the POL-2 instrument. The BISTRO data cover the entire NGC 1333 complex (∼1.5 pc ? 2 pc) at 0.02 pc resolution and spatially resolve the polarized emission from individual filamentary structures for the first time. The inferred magnetic field structure is complex as a whole, with each individual filament aligned at different position angles relative to the local field orientation. We combine the BISTRO data with low- and high- resolution data derived from Planck and interferometers to study the multiscale magnetic field structure in this region. The magnetic field morphology drastically changes below a scale of ∼1 pc and remains continuous from the scales of filaments (∼0.1 pc) to that of protostellar envelopes (∼0.005 pc or ∼1000 au). Finally, we construct simple models in which we assume that the magnetic field is always perpendicular to the long axis of the filaments. We demonstrate that the observed variation of the relative orientation between the filament axes and the magnetic field angles are well reproduced by this model, taking into account the projection effects of the magnetic field and filaments relative to the plane of the sky. These projection effects may explain the apparent complexity of the magnetic field structure observed at the resolution of BISTRO data toward the filament network.
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| 16. |
- Fan, Zhiwen, et al.
(author)
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Porous Ionic Network/CNT Composite Separator as a Polysulfide Snaring Shield for High Performance Lithium–Sulfur Battery
- 2023
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In: Macromolecular rapid communications. - 1022-1336 .- 1521-3927. ; 44:24
-
Journal article (peer-reviewed)abstract
- Lithium–sulfur (Li–S) battery features a high theoretical energy density, but the shuttle of soluble polysulfides between the two electrodes often results in a rapid capacity decay. Herein, a straightforward electrostatic adsorption strategy based on a cross-linked polyimidazolium separator as a snaring shield of polysulfides is reported, which suppresses the undesirable migration of polysulfides to the anode. The porous ionic network (PIN)-modified carbon nanotubes (CNTs) are successfully prepared and coated onto a commercial porous polypropylene membrane in a vacuum-filtration step. The favorable affinity of the imidazolium ring toward polysulfide via the polar interaction and the electrostatic effect of ions mitigates the undesirable shuttle of polysulfides in the electrolyte, improving the Li─S battery in terms of rate performance and cycling life. Compared to the reference PIN-free CNT-coated separator, the PIN/CNT-coated one has an increased initial capacity of 1.3 folds (up to 1394.8 mAh g−1 for PIN/CNT/PP-3) at 0.1 C.
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| 17. |
- Fu, Li, et al.
(author)
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Effects of long-term exposure to ambient fine particulate matter and its specific components on blood pressure and hypertension incidence
- 2024
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In: Environment International. - 0160-4120 .- 1873-6750. ; 184
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Journal article (peer-reviewed)abstract
- Background: Epidemiological evidence on the association of PM2.5 (particulate matter with aerodynamic diameter ≤ 2.5 μm) and its specific components with hypertension and blood pressure is limited. Methods: We applied information of participants from the World Health Organization's (WHO) Study on Global Ageing and Adult Health (SAGE) to estimate the associations of long-term PM2.5 mass and its chemical components exposure with blood pressure (BP) and hypertension incidence in Chinese adults ≥ 50 years during 2007–2018. Generalized linear mixed model and Cox proportional hazard model were applied to investigate the effects of PM2.5 mass and its chemical components on the incidence of hypertension and BP, respectively. Results: Each interquartile range (IQR = 16.80 μg/m3) increase in the one-year average of PM2.5 mass concentration was associated with a 17 % increase in the risk of hypertension (HR = 1.17, 95 % CI: 1.10, 1.24), and the population attributable fraction (PAF) was 23.44 % (95 % CI: 14.69 %, 31.55 %). Each IQR μg/m3 increase in PM2.5 exposure was also related to increases of systolic blood pressure (SBP) by 2.54 mmHg (95 % CI:1.99, 3.10), and of diastolic blood pressure (DBP) by 1.36 mmHg (95 % CI: 1.04, 1.68). Additionally, the chemical components of SO42−, NO3−, NH4+, OM, and BC were also positively associated with an increased risk of hypertension incidence and elevated blood pressure. Conclusions: These results indicate that long-term exposure to PM2.5 mass and its specific components may be major drivers of escalation in hypertension diseases.
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| 18. |
- Guo, Yong, et al.
(author)
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Deposition of droplets from the trachea or bronchus in the respiratory tract during exhalation : A steady-state numerical investigation
- 2020
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In: Aerosol Science and Technology. - : Informa UK Limited. - 0278-6826 .- 1521-7388. ; 54:8, s. 869-879
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Journal article (peer-reviewed)abstract
- Respiratory droplets are bioaerosols that originate from the respiratory tract. Knowing their deposition characteristics during exhalation would facilitate the understanding of the source of large respiratory droplets and their importance in the spread of respiratory infectious diseases. In this study, computational fluid dynamics is used to simulate the motion and deposition of droplets released from either trachea or bronchi in a realistic reconstruction of the human respiratory tract. Influences of airflow structures and locations of droplet generation on droplet deposition are studied, and droplets with diameters between 1 and 50 mu m are examined. The deposition of droplets is found to be influenced mainly by the droplet diameter and the flow rate of exhalation. The number of droplets released from the trachea or bronchi that can escape into the environment decreases as the flow rate increases. When the flow rate is low (10 L/min), the critical diameter of droplets generated in the lower respiratory system that can escape into the air is approximately 12 mu m, but this diameter is approximately 5 mu m when the flow rate is medium (30 to 60 L/min) or large (90 L/min). The larynx is the dominant site of deposition for droplets smaller than the critical diameter, while trachea and bronchus are more important locations that account for the deposition of larger droplets. This study indicates that the lower respiratory tract is an important source of fine droplets (<5 mu m) in indoor environments, and larger droplets probably originate from the upper respiratory tract, which needs further investigation. Copyright
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| 19. |
- Heap, Michael J., et al.
(author)
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The tensile strength of volcanic rocks : Experiments and models
- 2021
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In: Journal of Volcanology and Geothermal Research. - : Elsevier. - 0377-0273 .- 1872-6097. ; 418
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Journal article (peer-reviewed)abstract
- The tensile strength of volcanic rock exerts control over several key volcanic processes, including fragmentation and magma chamber rupture. Despite its importance, there is a paucity of laboratory data for the tensile strength of volcanic rocks, leading to an incomplete understanding of the influence of microstructural parameters, such as pore size and shape (factors that vary widely for volcanic rocks), on their tensile strength. To circumvent problems associated with the variability of natural samples, we provide here a systematic study in which we use elastic damage mechanics code "Rock Failure Process Analysis" to perform numerical experiments to better understand the influence of porosity, pore diameter, pore aspect ratio, and pore orientation on the tensile strength of volcanic rocks. We find that porosity and pore diameter exert a first-order control on the tensile strength of volcanic rocks, and that pore aspect ratio and orientation also influence tensile strength. Tensile strength is reduced by up to a factor of two as porosity is increased from 0.05 to 0.35 or as pore diameter is increased from 1 to 2 mm. Small, but systematic, reductions in tensile strength are observed as the angle between the loading direction and the major axis of an elliptical pore is increased from 0 to 90 degrees. The influence of pore aspect ratio (the ratio of the minor to major axis of an ellipse) depends on the pore angle: when the pore angle is 0 degrees, a decrease in pore aspect ratio, from 1 (a circle) to 0.2, increases the tensile strength, whereas the same decrease in pore aspect ratio does not substantially change the tensile strength when the pore angle is 90 degrees. These latter numerical experiments show that the tensile strength of volcanic rocks can be anisotropic. Our numerical data are in broad agreement with new and compiled experimental data for the tensile strength of volcanic rocks. One of the goals of this contribution is to provide better constrained constitutive models for the tensile strength of volcanic rocks for use in volcano modelling. To this end, we present a series of theoretical and semi-empirical constitutive models that can be used to determine the tensile strength of volcanic rocks, and highlight how tensile strength estimations can influence predictions of magma overpressures and assessments of the volume and radius of a magma chamber. (c) 2021 Elsevier B.V. All rights reserved.
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| 20. |
- Hwang, Jihye, et al.
(author)
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The JCMT BISTRO Survey: A Spiral Magnetic Field in a Hub-filament Structure, Monoceros R2
- 2022
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In: Astrophysical Journal. - : American Astronomical Society. - 1538-4357 .- 0004-637X. ; 941:1
-
Journal article (peer-reviewed)abstract
- We present and analyze observations of polarized dust emission at 850 μm toward the central 1 × 1 pc hub-filament structure of Monoceros R2 (Mon R2). The data are obtained with SCUBA-2/POL-2 on the James Clerk Maxwell Telescope (JCMT) as part of the B-fields in Star-forming Region Observations survey. The orientations of the magnetic field follow the spiral structure of Mon R2, which are well described by an axisymmetric magnetic field model. We estimate the turbulent component of the magnetic field using the angle difference between our observations and the best-fit model of the underlying large-scale mean magnetic field. This estimate is used to calculate the magnetic field strength using the Davis–Chandrasekhar–Fermi method, for which we also obtain the distribution of volume density and velocity dispersion using a column density map derived from Herschel data and the C18O (J = 3 - 2) data taken with HARP on the JCMT, respectively. We make maps of magnetic field strengths and mass-to-flux ratios, finding that magnetic field strengths vary from 0.02 to 3.64 mG with a mean value of 1.0 ± 0.06 mG, and the mean critical mass-to-flux ratio is 0.47 ± 0.02. Additionally, the mean Alfvén Mach number is 0.35 ± 0.01. This suggests that, in Mon R2, the magnetic fields provide resistance against large-scale gravitational collapse, and the magnetic pressure exceeds the turbulent pressure. We also investigate the properties of each filament in Mon R2. Most of the filaments are aligned along the magnetic field direction and are magnetically subcritical.
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| 21. |
- Li, Guoshuai, et al.
(author)
-
Site selection of desert solar farms based on heterogeneous sand flux
- 2024
-
In: npj Climate and Atmospheric Science. - 2397-3722. ; 7:1
-
Journal article (peer-reviewed)abstract
- Site selection for building solar farms in deserts is crucial and must consider the dune threats associated with sand flux, such as sand burial and dust contamination. Understanding changes in sand flux can optimize the site selection of desert solar farms. Here we use the ERA5-Land hourly wind data with 0.1° × 0.1° resolution to calculate the yearly sand flux from 1950 to 2022. The mean of sand flux is used to score the suitability of global deserts for building solar farms. We find that the majority of global deserts have low flux potential (≤ 40 m3 m-1 y-1) and resultant flux potential (≤ 2.0 m3 m-1 y-1) for the period 1950–2022. The scoring result demonstrates that global deserts have obvious patchy distribution of site suitability for building solar farms. Our study contributes to optimizing the site selection of desert solar farms, which aligns with the United Nations sustainability development goals for achieving affordable and clean energy target by 2030.
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| 22. |
- Li, Wenyun, et al.
(author)
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Personalized microbial fingerprint associated with differential glycemic effects of a whole grain rye intervention on Chinese adults
- 2024
-
In: Molecular Nutrition & Food Research. - : John Wiley & Sons. - 1613-4125 .- 1613-4133.
-
Journal article (peer-reviewed)abstract
- Scope: This study aims to identify the gut enterotypes that explain differential responses to intervention with whole grain rye by proposing an “enterotype - metabolic” model.Methods and results: A 12-week randomized controlled trial is conducted in Chinese adults, with 79 subjects consuming whole grain products with fermented rye bran (FRB) and 77 consuming refined wheat products in this exploratory post-hoc analysis. Responders or non-responders are identified according to whether blood glucose decreased by more than 10% after rye intervention. Compared to non-responders, responders in FRB have higher baseline Bacteroides (p < 0.001), associated with reduced blood glucose (p < 0.001), increased Faecalibacterium (p = 0.020) and Erysipelotrichaceae_UCG.003 (p = 0.022), as well as deceased 7β-hydroxysteroid dehydrogenase (p = 0.033) after intervention. The differentiated gut microbiota and metabolites between responders and non-responders after intervention are enriched in aminoacyl-tRNA biosynthesis.Conclusion: The work confirms the previously suggested importance of microbial enterotypes in differential responses to whole grain interventions and supports taking enterotypes into consideration for improved efficacy of whole grain intervention for preventing type 2 diabetes. Altered short-chain fatty acids and bile acid metabolism might be a potential mediator for the beneficial effects of whole grain rye on glucose metabolism.
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| 23. |
- Lind, Lars, et al.
(author)
-
Heterogeneous contributions of change in population distribution of body mass index to change in obesity and underweight NCD Risk Factor Collaboration (NCD-RisC)
- 2021
-
In: eLife. - : eLife Sciences Publications Ltd. - 2050-084X. ; 10
-
Journal article (peer-reviewed)abstract
- From 1985 to 2016, the prevalence of underweight decreased, and that of obesity and severe obesity increased, in most regions, with significant variation in the magnitude of these changes across regions. We investigated how much change in mean body mass index (BMI) explains changes in the prevalence of underweight, obesity, and severe obesity in different regions using data from 2896 population-based studies with 187 million participants. Changes in the prevalence of underweight and total obesity, and to a lesser extent severe obesity, are largely driven by shifts in the distribution of BMI, with smaller contributions from changes in the shape of the distribution. In East and Southeast Asia and sub-Saharan Africa, the underweight tail of the BMI distribution was left behind as the distribution shifted. There is a need for policies that address all forms of malnutrition by making healthy foods accessible and affordable, while restricting unhealthy foods through fiscal and regulatory restrictions.
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| 24. |
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| 25. |
- Liu, Wei, et al.
(author)
-
Coherent dynamics of multi-spin V-B(-) center in hexagonal boron nitride
- 2022
-
In: Nature Communications. - : Nature Portfolio. - 2041-1723. ; 13:1
-
Journal article (peer-reviewed)abstract
- Hexagonal boron nitride (hBN) has recently been demonstrated to contain optically polarized and detected electron spins that can be utilized for implementing qubits and quantum sensors in nanolayered-devices. Understanding the coherent dynamics ofmicrowave driven spins in hBN is of crucial importance for advancing these emerging new technologies. Here, we demonstrate and study the Rabi oscillation and related phenomena of a negatively charged boron vacancy (V-B(-)) spin ensemble in hBN. We report on different dynamics of the V-B(-) spins at weak and strong magnetic fields. In the former case the defect behaves like a single electron spin system, while in the latter case it behaves like a multi-spin system exhibiting multiple-frequency dynamical oscillation as beat in the Ramsey fringes. We also carry out theoretical simulations for the spin dynamics of V-B(-) and reveal that the nuclear spins can be driven via the strong electron nuclear coupling existing in V-B(-) center, which can be modulated by the magnetic field and microwave field.
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| 26. |
- Liu, Yong-feng, et al.
(author)
-
A turn-on ratiometric fluorescent nanoprobe based on AgInZnS and nitrogen-doped graphene quantum dots for Cd2+ detection in lake water
- 2022
-
In: Journal of Materials Science. - : Springer Nature. - 0022-2461 .- 1573-4803. ; 57:36, s. 17336-17346
-
Journal article (peer-reviewed)abstract
- Excessive Cd2+ poses adverse influences on ecosystem and human beings, but its precise detection via a facile and environment-friendly method with resistance to interference is still a challenge. Here, a turn-on ratiometric fluorescent nanoprobe for Cd2+ detection is established using yellow-emission AgInZnS quantum dots (AIZS QDs) and blue-emission nitrogen-doped graphene quantum dots (NGQDs), which serve as a recognition unit and internal reference signal, respectively. Cd2+ could enhance the fluorescence of AIZS QDs due to the passivation of surface defects, while it has no significant effect on that of NGQDs. This nanoprobe has a large detection range from 0.5 to 100 µM and a limit of detection low to 28.6 nM. It shows strong anti-interference ability for Cd2+ even in lake water samples with recovery from 98 to 101% and low relative standard deviation of 1.01%, indicating its excellent effectuation to real-application world.
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| 27. |
- Liu, Yong-feng, et al.
(author)
-
Hydrophilic AgInZnS quantum dots as a fluorescent turn-on probe for Cd2+ detection
- 2021
-
In: Journal of Alloys and Compounds. - : Elsevier. - 0925-8388 .- 1873-4669.
-
Journal article (peer-reviewed)abstract
- Quantum dots (QDs) are intensively studied and developed for the detection of toxic heavy metal ions, notably Cd2+. However, a severe drawback is that the probing QDs themselves often are based on highly toxic elements, such as Pb or Cd. Here, we report on a one-step aqueous synthesis of more benign and hydrophilic AgInZnS QDs using 3-mercaptopropionic acid as a ligand with a high photoluminescence quantum yield of up to 41%, which were successfully employed as a fluorescent probe with a turn-on mode for detection of Cd2+ in aqueous solutions. Specifically, we determine that the effective detection range of Cd2+ in aqueous solution is 0.1–290 μM, with the lower limit of detection being 37.8 nM. We further establish that the excellent turn-on detection of Cd2+ is due to that surface defects on the AgInZnS QDs are effectively passivated by the Cd2+, as verified by a prolonged fluorescent lifetime and an increased photoluminescence quantum yield. We finally demonstrate that the AgInZnS QD probe is capable of detecting Cd2+ in lake water samples, and that it meets the WHO standard.
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| 28. |
- Ma, Ruijie, et al.
(author)
-
All-polymer solar cells with over 16% efficiency and enhanced stability enabled by compatible solvent and polymer additives
- 2022
-
In: Aggregate. - : Wiley. - 2692-4560 .- 2766-8541. ; 3:3
-
Journal article (peer-reviewed)abstract
- Considering the robust and stable nature of the active layers, advancing the power conversion efficiency (PCE) has long been the priority for all-polymer solar cells (all-PSCs). Despite the recent surge of PCE, the photovoltaic parameters of the state-of-the-art all-PSC still lag those of the polymer:small molecule-based devices. To compete with the counterparts, judicious modulation of the morphology and thus the device electrical properties are needed. It is difficult to improve all the parameters concurrently for the all-PSCs with advanced efficiency, and one increase is typically accompanied by the drop of the other(s). In this work, with the aids of the solvent additive (1-chloronaphthalene) and the n-type polymer additive (N2200), we can fine-tune the morphology of the active layer and demonstrate a 16.04% efficient all-PSC based on the PM6:PY-IT active layer. The grazing incidence wide-angle X-ray scattering measurements show that the shape of the crystallites can be altered, and the reshaped crystallites lead to enhanced and more balanced charge transport, reduced recombination, and suppressed energy loss, which lead to concurrently improved and device efficiency and stability.
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| 29. |
- Mishra, A, et al.
(author)
-
Diminishing benefits of urban living for children and adolescents' growth and development
- 2023
-
In: Nature. - : Springer Science and Business Media LLC. - 1476-4687 .- 0028-0836. ; 615:7954, s. 874-883
-
Journal article (peer-reviewed)abstract
- Optimal growth and development in childhood and adolescence is crucial for lifelong health and well-being1–6. Here we used data from 2,325 population-based studies, with measurements of height and weight from 71 million participants, to report the height and body-mass index (BMI) of children and adolescents aged 5–19 years on the basis of rural and urban place of residence in 200 countries and territories from 1990 to 2020. In 1990, children and adolescents residing in cities were taller than their rural counterparts in all but a few high-income countries. By 2020, the urban height advantage became smaller in most countries, and in many high-income western countries it reversed into a small urban-based disadvantage. The exception was for boys in most countries in sub-Saharan Africa and in some countries in Oceania, south Asia and the region of central Asia, Middle East and north Africa. In these countries, successive cohorts of boys from rural places either did not gain height or possibly became shorter, and hence fell further behind their urban peers. The difference between the age-standardized mean BMI of children in urban and rural areas was <1.1 kg m–2 in the vast majority of countries. Within this small range, BMI increased slightly more in cities than in rural areas, except in south Asia, sub-Saharan Africa and some countries in central and eastern Europe. Our results show that in much of the world, the growth and developmental advantages of living in cities have diminished in the twenty-first century, whereas in much of sub-Saharan Africa they have amplified.
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| 30. |
- Peng, Chen, et al.
(author)
-
Industrial Internet of Things enabled supply-side energy modelling for refined energy management in aluminium extrusions manufacturing
- 2021
-
In: Journal of Cleaner Production. - : Elsevier Science Ltd. - 0959-6526 .- 1879-1786. ; 301
-
Journal article (peer-reviewed)abstract
- To improve industrial sustainability performance in manufacturing, energy management and optimi-sation are key levers. This is particularly true for aluminium extrusions manufacturing dan energy -intensive production system with considerable environmental impacts. Many energy management and optimisation approaches have been studied to relieve such negative impact. However, the effectiveness of these approaches is compromised without the support of refined supply-side energy consumption information. Industrial internet of things provides opportunities to acquire refined energy consumption information in its data-rich environment but also poses a range of difficulties in implementation. The existing sensors cannot directly obtain the energy consumption at the granularity of a specific job. To acquire that refined energy consumption information, a supply-side energy modelling method based on existing industrial internet of things devices for energy-intensive production systems is proposed in this paper. First, the job-specified production event concept is proposed, and the layout of the data acqui-sition network is designed to obtain the event elements. Second, the mathematical models are developed to calculate the energy consumption of the production event in three process modes. Third, the energy consumption information of multiple manufacturing element dimensions can be derived from the mathematical models, and therefore, the energy consumption information on multiple dimensions is easily scaled. Finally, a case of refined energy cost accounting is studied to demonstrate the feasibility of the proposed models. ? 2021 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
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| 31. |
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| 32. |
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| 33. |
- Tang, B-B, et al.
(author)
-
Electron Mixing and Isotropization in the Exhaust of Asymmetric Magnetic Reconnection With a Guide Field
- 2020
-
In: Geophysical Research Letters. - : American Geophysical Union (AGU). - 0094-8276 .- 1944-8007. ; 47:14
-
Journal article (peer-reviewed)abstract
- We investigate an exhaust crossing of asymmetric guide field reconnection observed by Magnetospheric Multiscale (MMS) mission at Earth's dayside magnetopause. One MMS spacecraft (MMS 4) observes multicomponent electron distributions, including two counterstreaming electron beams, while the other three MMS spacecraft, with a separation of similar to 30 km, record nearly isotropic electron distributions. As counterstreaming electrons are unstable for the electron two-stream instability, our observations suggest that the electrostatic waves generated by the fast-growing electron two-stream instability can contribute to the rapid isotropization of electron distributions in the reconnection exhaust, indicating that wave-particle interactions play an important role in electron dynamics.
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| 34. |
- Tang, J, et al.
(author)
-
Cancer cells escape p53's tumor suppression through ablation of ZDHHC1-mediated p53 palmitoylation
- 2021
-
In: Oncogene. - : Springer Science and Business Media LLC. - 1476-5594 .- 0950-9232. ; 40:35, s. 5416-5426
-
Journal article (peer-reviewed)abstract
- The inactivation of tumor-suppressor genes contributes heavily to oncogenesis. The mutation of TP53 has been well-studied and recognized as a major factor in the development of tumors. Yet other means of p53 inactivation has not been well-elucidated. We previously identified a hypermethylated gene ZDHHC1 that suppresses tumor growth when the expression was restored, but the specific mechanism was yet to be found. The protein product of ZDHHC1 is an S-palmitoyltransferase and we have identified p53 as a substrate for ZDHHC1-mediated palmitoylation, specifically at the C135, C176, and C275 residues. The novel form of post-translational modification of p53 is required for the nuclear translocation of the tumor suppressor. p53 recruited DNMT3A to ZDHHC1 promoter and is responsible for the hypermethylation of ZDHHC1. The epigenetic feedback loop formed by ZDHHC1 and p53 sheds light on the inactivation of p53 without the presence of genetic mutations.
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| 35. |
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| 36. |
- Wang, Tao, et al.
(author)
-
The adverse impact of electric vehicles on traffic congestion in the morning commute
- 2021
-
In: Transportation Research, Part C: Emerging Technologies. - : Elsevier BV. - 0968-090X. ; 125
-
Journal article (peer-reviewed)abstract
- Many governments around the world are striving to promote the development of EVs for EV's sustainability and efficiency. However, EVs may induce extra traffic congestion in the morning commute. To illustrate this point, we incorporate the vehicle's energy consumption (EC) into the classical morning commute model to explore the EV's influence on the morning commute. First, we study the impact of the vehicle's EC on the waiting time in the user equilibrium (UE) state. Second, the properties of commuter's waiting time in the traffic system with EVs and gasoline vehicles (GVs) are analyzed. Finally, two interventions are proposed to alleviate the extra traffic congestion caused by EVs. The analytical and numerical results of this study reveal that i) EVs will induce extra traffic congestion, and ii) we can apply some interventions to alleviate the side effect of EVs and reap more benefits from EVs. The conclusions indicate that some interventions should be conducted when EVs enter the traffic system, which sheds light on the policymaking for the promotion of EVs.
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| 37. |
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| 38. |
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| 39. |
- Xi, Qiaojuan, et al.
(author)
-
中国主要流域灰-绿-蓝蓄水能力时空演变 : [Spatio-temporal variation of gray-green-blue storage capacity in nine major basins of China]
- 2021
-
In: Chinese Science Bulletin-Chinese. - 0023-074X .- 2095-9419. ; 66:34, s. 4437-4448
-
Journal article (peer-reviewed)abstract
- Most of China's territory is influenced by the East Asia monsoon, and thus, the spatio-temporal distribution of surface water resources in China is extremely uneven, causing many water-related issues, e.g.. water scarcity and flooding. As the basis and essential condition of economic and social development, water-related infrastructures provide the material basis and guarantee for regulating and storing surface water resources and solving multi-dimensional water problems. The infrastructures that play an important role in surface water resource regulation and storage mainly include three types: Gray (such as dams), green (such as forests), and blue infrastructures (such as lakes). Gray infrastructures can reduce the flood peak and increase water supply during dry seasons by regulating and storing water so that the seasonal and inter-annual fluctuation of runoff is reduced, which plays an important role in water storage, water supply, flood control, and disaster mitigation. However, excessive gray infrastructures would have adverse effects on the social economy and environmental ecology. Unlike gray infrastructures, green and blue infrastructures can not only benefit water resource management but also have ecological functions, such as improving water quality and enhancing ecosystem services. Thus. it is significant to couple gray, green, and blue infrastructures to regulate the spatio-temporal distribution of water resources. However, research on the spatial distribution and temporal variation of water storage capacity is still lacking, which hinders the coordinated regulation and comprehensive management of surface water resources. Therefore, in the present study, the spatio-temporal distribution of the three aforementioned infrastructures was compared and analyzed on basin scale, based on the latest data of darns, root zone storage capacity, natural lakes, and so on. Results indicated the following: (1) Gray water storage capacity has exceeded that of the natural terrestrial surface ecosystem in the Yangtze River Basin and the Southeast Basins, where human activities are intense. (2) Gray water storage capacity has increased significantly in nine major basins from 1955 to 2020, but the timing of construction varies in different basins. (3) Green water storage capacity did not change much, the Songhua-Liaohe River Basin and the Huaihe River Basin increased slightly. (4) Blue water storage capacity shows a constantly increasing trend on the whole, in which the water storage capacity in the inland river basin (including the endorheic basin on the Tibetan Plateau) significantly increased. Our study revealed the basic information and spatio-temporal variation of gray-green-blue water storage capacities in nine major basins of China, which could lead to better coordination between natural and artificial water infrastructures and provide support for multidimensional optimization of water resource allocation.
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| 40. |
- Xie, Haibing, et al.
(author)
-
Decoupling the effects of defects on efficiency and stability through phosphonates in stable halide perovskite solar cells
- 2021
-
In: Joule. - : CELL PRESS. - 2542-4351. ; 5:5, s. 1246-1266
-
Journal article (peer-reviewed)abstract
- Understanding defects is of paramount importance for the development of stable halide perovskite solar cells (PSCs). However, isolating their distinctive effects on device efficiency and stability is currently a challenge. We report that adding the organic molecule 3-phosphonopropionic acid (H3pp) to the halide perovskite results in unchanged overall optoelectronic performance while having a tremendous effect on device stability. We obtained PSCs with similar to 21% efficiency that retain similar to 100% of the initial efficiency after 1,000 h at the maximum power point under simulated AM1.5G illumination. The strong interaction between the perovskite and the H3pp molecule through two types of hydrogen bonds (H center dot center dot center dot I and O center dot center dot center dot H) leads to shallow point defect passivation that has a significant effect on device stability but not on the non-radiative recombination and device efficiency. We expect that our work will have important implications for the current understanding and advancement of operational PSCs.
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| 41. |
- Yang, Weizhao, et al.
(author)
-
Transcriptome sequencing provides evidence of genetic assimilation in a toad-headed lizard at high altitude
- 2021
-
In: Asian Herpetological Research. - 2095-0357. ; 12:3, s. 315-322
-
Journal article (peer-reviewed)abstract
- Understanding how organisms adapt to the environment is a compelling question in modern evolutionary biology. Genetic assimilation provides an alternative hypothesis to explain adaptation, in which phenotypic plasticity is first triggered by environmental factors, followed by selection on genotypes that reduce the plastic expression of phenotypes. To investigate the evidence of genetic assimilation in a high-altitude dweller, the toad-headed agama Phr ynocephalus vlangalii, we conducted a translocation experiment by moving individuals from high-to low-altitude environments. We then measured their gene expression profiles by transcriptome sequencing in heart, liver and muscle, and compared them to two low-altitude species P. axillaris and P. fors ythii. The results showed that the general expression profile of P. vlangalii was similar to its viviparous relative P. fors ythii, however, the differentially expressed genes in the liver of P. vlangalii showed a distinct pattern compared to both the low-altitude species. In particular, several key genes (FASN, ACAA2 and ECI2) within fatty acid metabolic pathway were no longer differentially expressed in P. valgnalii, suggesting the loss of plasticity for this pathway after translocation. This study provides evidence of genetic assimilation in fatty acid metabolism that may have facilitated the adaptation to high-altitude for P. vlangalii.
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| 42. |
- Ye, Lei, et al.
(author)
-
Toward environmentally friendly direct reduced iron production : A novel route of comprehensive utilization of blast furnace dust and electric arc furnace dust
- 2021
-
In: Waste Management. - : Elsevier. - 0956-053X .- 1879-2456. ; 135, s. 389-396
-
Journal article (peer-reviewed)abstract
- In this study, a novel method for producing direct reduced iron (DRI) powders based on microwave-assisted self reduction of core-shell composite pellets composed of blast furnace (BF) dust and hazardous electric arc furnace (EAF) dust followed by magnetic separation was reported. The proper core-shell structure of the composite pellets was designed according to the rule of impedance matching and properties of BF dust and EAF dust by adjusting the thickness of shell (i.e., thickness of impedance matching layer) via controlling the C/O molar ratio of the raw materials from 0.55 to 0.70. The results showed that the EAF dust with high content of CaO was beneficial to the mechanical strength of green, dried, and metallized pellets (collected after reduction), while the BF dust with high content of carbon enabled sufficient microwave-assisted reduction of the pellets, facilitating subsequent magnetic separation and also the removal of zinc from EAF dust. By reduction of the core-shell BF dust-EAF dust composite pellets with the C/O molar ratio of 0.65 at 1050 degrees C for 15 min, the resulting metallized pellets showed superior reduction and magnetic separation indexes with higher removal percentages of zinc and lead, in comparison with conventional metallized pellets. The DRI powders obtained after magnetic separation had total iron content of 91.2 wt%, iron metallization degree of 95.8%, yield of 68.1%, and iron recovery of 88.0%. This study provided a good example for efficient and environmentally friendly comprehensive utilization of typical and hazardous wastes in the iron and steel industry.
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| 43. |
- Ye, Tong, et al.
(author)
-
Valence engineering at the interface of MoS2/Mo2C heterostructure for bionic nitrogen reduction
- 2023
-
In: Chemical Engineering Journal. - : Elsevier BV. - 1385-8947 .- 1873-3212. ; 452
-
Journal article (peer-reviewed)abstract
- The natural nitrogenase is still the most efficient catalyst on earth to reduce the ambient N2 into ammonia. The central part of the molecular machine is powered by a metallic core, usually a molybdenum atom, whose co-ordination valence state remains an enigma for us to unveil and mimic. Unlike the flexible bio-enzyme, inorganic heterogeneous catalysts are usually rigid in the coordination structure, making their valence states invariable, except some localized defects. In this study, we successfully synthesized a two-dimensional MoS2/Mo2C elec-trocatalyst, which contains a heterostructured interface with efficient charge and magnetism separation, exhibiting a gradual and broad valence state transition from Mo4+ to Mo2+. Density functional theory (DFT) calculations reveal that Mo3+ sites at the interface have a strong N2 adsorption energy of -0.75 eV with the side -on configuration, and an activated hydrogenation of *NH2 species. This bionic electrocatalyst displays a splendid performance in nitrogen reduction reaction with a Faradic efficiency of 42 % at-0.1 V vs RHE.
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| 44. |
- Zhang, Man, et al.
(author)
-
Terahertz Reading of Ferroelectric Domain Wall Dielectric Switching
- 2021
-
In: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 13:10, s. 12622-12628
-
Journal article (peer-reviewed)abstract
- Ferroelectric domain walls (DWs) are important nanoscale interfaces between two domains. It is widely accepted that ferroelectric domain walls work idly at terahertz (THz) frequencies, consequently discouraging efforts to engineer the domain walls to create new applications that utilize THz radiation. However, the present work clearly demonstrates the activity of domain walls at THz frequencies in a lead-free Aurivillius phase ferroelectric ceramic, Ca0.99Rb0.005Ce0.005Bi2Nb2O9, examined using THz-time-domain spectroscopy (THz-TDS). The dynamics of domain walls are different at kHz and THz frequencies. At low frequencies, domain walls work as a group to increase dielectric permittivity. At THz frequencies, the defective nature of domain walls serves to lower the overall dielectric permittivity. This is evidenced by higher dielectric permittivity in the THz band after poling, reflecting decreased domain wall density. An elastic vibrational model has also been used to verify that a single frustrated dipole in a domain wall represents a weaker contribution to the permittivity than its counterpart within a domain. The work represents a fundamental breakthrough in understanding the dielectric contributions of domain walls at THz frequencies. It also demonstrates that THz probing can be used to read domain wall dielectric switching.
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| 45. |
- Zhang, Xi, et al.
(author)
-
The GLIM criteria as an effective tool for nutrition assessment and survival prediction in older adult cancer patients
- 2021
-
In: Clinical Nutrition. - : Elsevier. - 0261-5614 .- 1532-1983. ; 40:3, s. 1224-1232
-
Journal article (peer-reviewed)abstract
- Background & aims: Elderly cancer patients are at particularly high risk for malnutrition because both the disease and the old age threaten their nutritional status. The Global Leadership Initiative on Malnutrition (GLIM) released new universal criteria for diagnosing and grading malnutrition, but the validation of these criteria in elderly cancer population is not well documented. Our objective was to investigate the application of the GLIM criteria in nutrition assessment and survival prediction in elderly cancer patients. Methods: This retrospective cohort analysis was conducted on a primary cohort of 1192 cancer patients aged 65 years or older enrolled from a multi-institutional registry, and a validation cohort of 300 elderly cancer patients treated at the First Affiliated Hospital of Sun Yat-sen University. Patients considered at -risk for malnutrition based on the NRS-20 02 were assessed using the GLIM criteria. The association between the nutritional status and patients' overall survival (OS) was then analyzed by the Kaplan-Meier method and a Cox model. A nomogram was also established that included additional inde-pendent clinical prognostic variables. To determine the predictive accuracy and discriminatory capacity of the nomogram, the C-index, receiver operating characteristic (ROC) curve and calibration curve were evaluated. Results: The percentage of patients considered & ldquo;at-risk & rdquo; for malnutrition was 64.8% and 67.3% for the primary and validation cohorts, respectively. GLIM-defined malnutrition was diagnosed in 48.4% of pa-tients in the primary cohort and 46.0% in the validation cohort. In the primary cohort, patients at risk of malnutrition (NRS-20 02 > 3) showed a worse OS than those with a NRS-20 02 < 3 (HR 1.34, 1.10-1.64; p = 0.003). Additionally, patients with GLIM-defined severe malnutrition (HR1.71, 1.37-2.14; p < 0.001) or moderate malnutrition (HR1.35, 1.09-1.66; p = 0.006) showed a significantly shorter OS compared to those without malnutrition. The nomogram incorporating the domains of the GLIM with other variables was accurate, especially for predicting the 1-and 2-year overall survival rates. Conclusions: The GLIM criteria can be used in elderly cancer patients not only to assess malnutrition, but also to predict survival outcome. The nomogram developed based on the GLIM domains can provide a more accurate prediction of the prognosis than existing systems. (c) 2020 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.
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| 46. |
- Zhong, Z. H., et al.
(author)
-
Evidence for Whistler Waves Propagating Into the Electron Diffusion Region of Collisionless Magnetic Reconnection
- 2022
-
In: Geophysical Research Letters. - : American Geophysical Union (AGU). - 0094-8276 .- 1944-8007. ; 49:7
-
Journal article (peer-reviewed)abstract
- Despite a growing number of observations of whistler waves in/around the reconnection diffusion region, the origin of the whistler waves in the diffusion region and their role in reconnection remain elusive. This paper investigates the whistler-mode waves within an electron-scale reconnecting current sheet observed by the Magnetospheric Multiscale mission on 23 December 2016. These whistlers were observed in both the electron diffusion region (EDR) and the immediate inflow region of the electron-scale magnetic reconnection site. The dispersion relation of these whistlers is measured and compared to predictions from linear theory for the first time in these regions. The comparison shows that the field-aligned drifting electron component critically modifies the dispersion relation of whistlers in the EDR due to the Doppler-shift effects. We demonstrate that these whistlers propagated into the EDR from outside rather than locally excited, however, they did not provide sufficiently large anomalous dissipation in this EDR.
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| 47. |
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