Background
Exposure to environmental pollutants promotes Th2 cell responses. Aryl hydrocarbon receptor (AhR) activation aggravates allergic responses. Epithelium‐derived thymic stromal lymphopoietin ...(TSLP), interleukin (IL)‐25, and IL‐33 are implicated in the dysregulation of Th2 immune responses in severe allergic asthma.
Methods
Bronchial biopsies of 28 allergic severe asthma and 6 mild asthma subjects from highly polluted areas were analyzed for AhR nuclear translocation (NT), cytokine expression, and gene activation. Cultured primary epithelial cells were stimulated with diesel exhausted particles (DEP) to determine AhR‐mediated IL‐33, Il‐25, and TSLP synthesis and release.
Results
Primary bronchial epithelial cells exposed to DEP showed upregulation of IL‐33, IL‐25, and TSLP. These effects were abolished by knockdown of AhR by siRNA. Increased AhR/ARNT binding to promoters of IL‐33, IL‐25, and TSLP was found using chromatin immunoprecipitation (ChIP) assay. Allergic severe asthma with high AhR NT had higher bronchial gene and protein expression of IL‐33, IL‐25, and TSLP. These patients derived clinical benefit from anti‐IgE treatment.
Conclusion
Aryl hydrocarbon receptor activation by DEP mediates upregulation of IL‐33, IL‐25, and TSLP with Th2 activation, potentially linking environmental pollution and allergic severe asthma.
Environmental diesel exhaust particles (DEP) exposed to airway epithelium ligate cytoplasmic aryl hydrocarbon receptor (AhR), translocate to the nucleus with aryl hydrocarbon receptor nuclear translocator (ARNT), and then transactivate IL‐33, Il‐25, and TSLP gene expression. Patients with high AhR nucleus translocation overexpressed IL‐33, Il‐25, and TSLP cytokines compared to those with low. Patients with high AhR nucleus translocation are more response to anti‐IgE therapy compared to those with low.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
By combining angle-resolved photoemission spectroscopy and quantum oscillation measurements, we performed a comprehensive investigation on the electronic structure of LaSb, which exhibits ...near-quadratic extremely large magnetoresistance (XMR) without any sign of saturation at magnetic fields as high as 40 T. We clearly resolve one spherical and one intersecting-ellipsoidal hole Fermi surfaces (FSs) at the Brillouin zone (BZ) center Γ and one ellipsoidal electron FS at the BZ boundary X. The hole and electron carriers calculated from the enclosed FS volumes are perfectly compensated, and the carrier compensation is unaffected by temperature. We further reveal that LaSb is topologically trivial but shares many similarities with the Weyl semimetal TaAs family in the bulk electronic structure. Based on these results, we have examined the mechanisms that have been proposed so far to explain the near-quadratic XMR in semimetals.
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Effective remediation of arsenic contaminated water remains a critical task from the environmental perspective, owing to the harmful effects of arsenic on human health and the environment. Recently, ...highly porous metal–organic frameworks (MOFs) with excellent chemical stability and abundant functional groups represent a significant new addition to the area of capturing aquatic arsenic pollutants. This review focuses on the development of MOF-based materials for the efficient removal of toxic arsenic species from aqueous solutions. Aspects related to the materials’ characteristics, application performance and interaction mechanisms are systematically studied, referencing the macroscopic experimental behaviors and microscopic spectroscopy analyses. The properties of various MOF-based materials are assessed and compared with those of other conventionally used materials. At last, insights and perspectives are suggested in terms of future research directions and development challenges. Overall, this class of materials demonstrates a promising potential for aquatic arsenic removal, and with a proper up-scaling development might it be used for practical applications in the near future.
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•Survey representative studies using MOFs for aquatic arsenic removal.•Assess MOFs application feasibility in terms of cost and development potential.•Conduct detailed comparison with other arsenic removal materials.•Provide significant insights and perspectives for future studies.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
► Substantially improved mechanical properties of 0.2C–5Mn steels. ► Intercritical austenization followed by short time annealing. ► Phase transformation induced plasticity of the large volume ...fractioned austenite. ► Dependence of yield stress on austenite grain size accords with Hall–Petch equation.
Microstructures and mechanical properties of 0.2C–5Mn steel processed under different heat treatment conditions were examined by scanning electron microscopy (SEM), Transmission electron microscopy (TEM) and X-ray diffraction (XRD). It was found that high temperature austenization (above Ac3) resulted in a full martensite structure after quenching, which gradually transformed into the ferrite/austenite duplex structure during the following annealing process. However, austenization in the intercritical region (between Ac1 and Ac3) gave a duplex structure after quenching, which was nearly not affected by followed annealing process. The ultrahigh strength ∼1000
MPa and total elongation ∼40% were only obtained in the specimens with 6
h annealing at 650
°C under both heat treatment conditions. However, the excellent mechanical properties could be obtained in the intercritically austenitized samples with only 10
min annealing at 650
°C. Based on the analysis on the relationship between microstructure and mechanical properties, it was found that the total elongation was strongly dependent on the austenite fraction, which was ascribed to the phase transformation induced plasticity of the large volume fraction of austenite. Otherwise, the dependence of the yield stress on the austenite grain size accords with Hall-Petch equation, which implies that the austenite is soft phase. It was concluded that 10
min annealing at 650
°C was enough to obtain a large volume fraction of austenite (∼30%) in 0.2C–5Mn steel when the specimens were austenitized at 675
°C.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Berry phase physics is closely related to a number of topological states of matter. Recently discovered topological semimetals are believed to host a nontrivial π Berry phase to induce a phase shift ...of ±1/8 in the quantum oscillation (+ for hole and - for electron carriers). We theoretically study the Shubnikov-de Haas oscillation of Weyl and Dirac semimetals, taking into account their topological nature and inter-Landau band scattering. For a Weyl semimetal with broken time-reversal symmetry, the phase shift is found to change nonmonotonically and go beyond known values of ±1/8 and ±5/8, as a function of the Fermi energy. For a Dirac semimetal or paramagnetic Weyl semimetal, time-reversal symmetry leads to a discrete phase shift of ±1/8 or ±5/8. Different from the previous works, we find that the topological band inversion can lead to beating patterns in the absence of Zeeman splitting. We also find the resistivity peaks should be assigned integers in the Landau index plot. Our findings may account for recent experiments in Cd_{2}As_{3} and should be helpful for exploring the Berry phase in various 3D systems.
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MicroRNAs have emerged as crucial regulators of cardiac homeostasis and remodeling in various cardiovascular diseases. We previously demonstrated that miR-221 regulated cardiac hypertrophy in vitro. ...In the present study, we demonstrated that the cardiac-specific overexpression of miR-221 in mice evoked cardiac dysfunction and heart failure. The lipidated form of microtubule-associated protein 1 light chain 3 was significantly decreased and sequestosome 1 was accumulated in cardiac tissues of transgenic (TG) mice, indicating that autophagy was impaired. Overexpression of miR-221 in vitro reduced autophagic flux through inhibiting autophagic vesicle formation. Furthermore, mammalian target of rapamycin (mTOR) was activated by miR-221, both in vivo and in vitro. The inactivation of mTOR abolished the miR-221-induced inhibition of autophagy and cardiac remodeling. Our previous study has demonstrated that cyclin-dependent kinase (CDK) inhibitor p27 was a direct target of miR-221 in cardiomyocytes. Consistently, the expression of p27 was markedly suppressed in the myocardia of TG mice. Knockdown of p27 by siRNAs was sufficient to mimic the effects of miR-221 overexpression on mTOR activation and autophagy inhibition, whereas overexpression of p27 rescued miR-221-induced autophagic flux impairment. Inhibition of CDK2 restored the impaired autophagic flux and rescued the cardiac remodeling induced by either p27 knockdown or miR-221 overexpression. These findings reveal that miR-221 is an important regulator of autophagy balance and cardiac remodeling by modulating the p27/CDK2/mTOR axis, and implicate miR-221 as a therapeutic target in heart failure.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Methane monooxygenases (MMOs) mediate the facile conversion of methane into methanol in methanotrophic bacteria with high efficiency under ambient conditions. Because the selective oxidation of ...methane is extremely challenging, there is considerable interest in understanding how these enzymes carry out this difficult chemistry. The impetus of these efforts is to learn from the microbes to develop a biomimetic catalyst to accomplish the same chemical transformation. Here, we review the progress made over the past two to three decades toward delineating the structures and functions of the catalytic sites in two MMOs: soluble methane monooxygenase (sMMO) and particulate methane monooxygenase (pMMO). sMMO is a water-soluble three-component protein complex consisting of a hydroxylase with a nonheme diiron catalytic site; pMMO is a membrane-bound metalloenzyme with a unique tricopper cluster as the site of hydroxylation. The metal cluster in each of these MMOs harnesses O2 to functionalize the CH bond using different chemistry. We highlight some of the common basic principles that they share. Finally, the development of functional models of the catalytic sites of MMOs is described. These efforts have culminated in the first successful biomimetic catalyst capable of efficient methane oxidation without overoxidation at room temperature.
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IJS, KILJ, NUK, PNG, UL, UM
The optical design and performance of the recently opened 13A biological small‐angle X‐ray scattering (SAXS) beamline at the 3.0 GeV Taiwan Photon Source of the National Synchrotron Radiation ...Research Center are reported. The beamline is designed for studies of biological structures and kinetics in a wide range of length and time scales, from angstrom to micrometre and from microsecond to minutes. A 4 m IU24 undulator of the beamline provides high‐flux X‐rays in the energy range 4.0–23.0 keV. MoB4C double‐multilayer and Si(111) double‐crystal monochromators (DMM/DCM) are combined on the same rotating platform for a smooth rotation transition from a high‐flux beam of ∼4 × 1014 photons s−1 to a high‐energy‐resolution beam of ΔE/E ≃ 1.5 × 10−4; both modes share a constant beam exit. With a set of Kirkpatrick–Baez (KB) mirrors, the X‐ray beam is focused to the farthest SAXS detector position, 52 m from the source. A downstream four‐bounce crystal collimator, comprising two sets of Si(311) double crystals arranged in a dispersive configuration, optionally collimate the DCM (vertically diffracted) beam in the horizontal direction for ultra‐SAXS with a minimum scattering vector q down to 0.0004 Å−1, which allows resolving ordered d‐spacing up to 1 µm. A microbeam, of 10–50 µm beam size, is tailored by a combined set of high‐heat‐load slits followed by micrometre‐precision slits situated at the front‐end 15.5 m position. The second set of KB mirrors then focus the beam to the 40 m sample position, with a demagnification ratio of ∼1.5. A detecting system comprising two in‐vacuum X‐ray pixel detectors is installed to perform synchronized small‐ and wide‐angle X‐ray scattering data collections. The observed beamline performance proves the feasibility of having compound features of high flux, microbeam and ultra‐SAXS in one beamline.
The optical design and performance of the BioSAXS beamline at the Taiwan Photon Source are reported
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FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
Nodal-line semimetals are topological semimetals in which band touchings form nodal lines or rings. Around a loop that encloses a nodal line, an electron can accumulate a nontrivial π Berry phase, so ...the phase shift in the Shubnikov-de Haas (SdH) oscillation may give a transport signature for the nodal-line semimetals. However, different experiments have reported contradictory phase shifts, in particular, in the WHM nodal-line semimetals (W=Zr/Hf, H=Si/Ge, M=S/Se/Te). For a generic model of nodal-line semimetals, we present a systematic calculation for the SdH oscillation of resistivity under a magnetic field normal to the nodal-line plane. From the analytical result of the resistivity, we extract general rules to determine the phase shifts for arbitrary cases and apply them to ZrSiS and Cu_{3}PdN systems. Depending on the magnetic field directions, carrier types, and cross sections of the Fermi surface, the phase shift shows rich results, quite different from those for normal electrons and Weyl fermions. Our results may help explore transport signatures of topological nodal-line semimetals and can be generalized to other topological phases of matter.
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The charge-density-wave (CDW) mechanism of the 3D quantum Hall effect has been observed recently in ZrTe5 Tang et al., Nature 569, 537 (2019). Different from previous cases, the CDW forms on a ...one-dimensional (1D) band of Landau levels, which strongly depends on the magnetic field. However, its theory is still lacking. We develop a theory for the CDW mechanism of 3D quantum Hall effect. The theory can capture the main features in the experiments. We find a magnetic field induced second-order phase transition to the CDW phase. We find that electron-phonon interactions, rather than electron-electron interactions, dominate the order parameter. We extract the electron-phonon coupling constant from the non-Ohmic I−V relation. We point out a commensurate-incommensurate CDW crossover in the experiment. More importantly, our theory explores a rare case, in which a magnetic field can induce an order-parameter phase transition in one direction but a topological phase transition in other two directions, both depend on one magnetic field.
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