Oligodendrocytes (OLs) death after spinal cord injury (SCI) contributes to demyelination, even leading to a permanent neurological deficit. Besides apoptosis, our previous study demonstrated that OLs ...underwent receptor-interacting serine-threonine kinase 3(RIP3)/mixed lineage kinase domain-like protein (MLKL)-mediated necroptosis. Considering that necroptosis is always accompanied with pro-inflammatory response and quercetin has long been used as anti-inflammatory agent, in the present study we investigated whether quercetin could inhibit necroptosis of OLs and suppress the M1 macrophages/microglia-mediated immune response after SCI as well as the possible mechanism.
In this study, we applied quercetin, an important flavonoid component of various herbs, to treat rats with SCI and rats injected with saline were employed as the control group. Locomotor functional recovery was evaluated using Basso-Beattie-Bresnahan (BBB) scoring and rump-height Index (RHI) assay. In vivo, the necroptosis, apoptosis, and regeneration of OLs were detected by immunohistochemistry, 5'-bromo-2'-deoxyuridine (BrdU) incorporation. The loss of myelin and axons after SCI were evaluated by Luxol fast blue (LFB) staining, immunohistochemistry, and electron microscopic study. The polarization of macrophages/microglia after SCI and the underlying mechanisms were detected by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and immunohistochemistry. In vitro, the ATP and reactive oxygen species (ROS) level examination, propidium iodide (PI) labeling, and Western blotting were used to analyze the necroptosis of cultured OLs, while the signaling pathways-mediated polarization of cultured macrophages/microglia was detected by qRT-PCR and Western blotting.
We demonstrated that quercetin treatment improved functional recovery in rats after SCI. We then found that quercetin significantly reduced necroptosis of OLs after SCI without influencing apoptosis and regeneration of OLs. Meanwhile, myelin loss and axon loss were also significantly reduced in quercetin-treated rats, as compared to SCI + saline control. Further, we revealed that quercetin could suppress macrophages/microglia polarized to M1 phenotype through inhibition of STAT1 and NF-κB pathway in vivo and in vitro, which contributes to the decreased necroptosis of OLs.
Quercetin treatment alleviated necroptosis of OLs partially by inhibiting M1 macrophages/microglia polarization after SCI. Our findings suggest that necroptosis of OLs may be a potential therapeutic target for clinical SCI.
Ethylene/polar monomer coordination copolymerization offers an attractive way of making functionalized polyolefins. However, ethylene copolymerization with industrially relevant short chain length ...alkenoic acid remain a big challenge. Here we report the efficient direct copolymerization of ethylene with vinyl acetic acid by tetranuclear nickel complexes. The protic monomer can be extended to acrylic acid, allylacetic acid, ω-alkenoic acid, allyl alcohol, and homoallyl alcohol. Based on X-ray analysis of precatalysts, control experiments, solvent-assisted electrospray ionization-mass spectrometry detection of key catalytic intermediates, and density functional theory studies, we propose a possible mechanistic scenario that involves a distinctive vinyl acetic acid enchainment enabled by Ni···Ni synergistic effects. Inspired by the mechanistic insights, binuclear nickel catalysts are designed and proved much more efficient for the copolymerization of ethylene with vinyl acetic acid or acrylic acid, achieving the highest turnover frequencies so far for both ethylene and polar monomers simultaneously.
The dielectric properties of Z-type hexaferrite Sr3Co2Fe24O41 (SCFO) have been investigated as a function of temperature from 153 to 503 K between 1 and 2 GHz. The dielectric responses of SCFO are ...found to be frequency dependent and thermally activated. The relaxation-type dielectric behavior is observed to be dominating in the low frequency region and resonance-type dielectric behavior is found to be dominating above 10(8) Hz. This frequency dependence of dielectric behavior is explained by the damped harmonic oscillator model with temperature dependent coefficients. The imaginary part of impedance (Z″) and modulus (M″) spectra show that there is a distribution of relaxation times. The scaling behaviors of Z″ and M″ spectra further suggest that the distribution of relaxation times is temperature independent at low frequencies. The dielectric loss spectra at different temperatures have not shown a scaling behavior above 10(8) Hz. A comparison between the Z″ and the M″ spectra indicates that the short-range charges motion dominates at low temperatures and the long-range charges motion dominates at high temperatures. The above results indicate that the dielectric dispersion mechanism in SCFO is temperature independent at low frequencies and temperature dependent at high frequencies due to the domination of resonance behavior.
A reversible benzothiazole-based fluorescent probe CF536 for sequential recognition of Cu2+ and S2− was designed and synthesized. The probe displayed high selectivity, a rapid response time, ...excellent water solubility due to introduction of the extremely hydrophilic trihydroxyl group and outstanding anti-interference ability for its large Stokes shift of 101nm.
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•A novel probe CF536 with a large Stokes shift of 101nm was developed.•The probe can achieve reversible detection of Cu2+ and S2− in 100% aqueous solution.•The single crystal of the probe was obtained.•This probe was successfully used to image living cells.
The selective detection of Cu2+ and S2− in pure water systems is very challenging. To address this problem, we here present a novel fluorescent probe CF536 for the reversible detection of Cu2+ and S2− in a 100% aqueous solution via a displacement approach based on fluorescence quenching and the ESIPT mechanism, and characterized by IR, NMR, HRMS and X-ray analysis. The introduction of Cu2+ (1.0 equiv.) to the aqueous solution of CF536 led to quenching of the intense green fluorescence within 2min. On the addition of S2− (3.0 equiv.), the emission of the ESIPT probe soon recovered from the CF536-Cu2+ system due to the abolishment of paramagnetic Cu2+. The fluorescence “ON-OFF-ON” cycle can be repeated a minimum of 5 times by the alternate addition of Cu2+ and S2−, implying that CF536 is a renewable dual-functional probe. The probe displayed high selectivity, a rapid response time, excellent water solubility due to introduction of the extremely hydrophilic trihydroxyl group and outstanding anti-interference ability for its large Stokes shift of 101nm (λabs=435nm, λem=536nm), thus making the method highly suitable for bioimaging. The probe CF536 was successfully used for fluorescent imaging of copper and hydrogen sulfide in living cells.
We report new Gaussian boson sampling experiments with pseudo-photon-number-resolving detection, which register up to 255 photon-click events. We consider partial photon distinguishability and ...develop a more complete model for the characterization of the noisy Gaussian boson sampling. In the quantum computational advantage regime, we use Bayesian tests and correlation function analysis to validate the samples against all current classical spoofing mockups. Estimating with the best classical algorithms to date, generating a single ideal sample from the same distribution on the supercomputer Frontier would take ∼600 yr using exact methods, whereas our quantum computer, Jiǔzhāng 3.0, takes only 1.27 μs to produce a sample. Generating the hardest sample from the experiment using an exact algorithm would take Frontier∼3.1×10^{10} yr.
Traditional H2O2 cleavage mediated by macroscopic electron transfer (MET) not only has low utilization of H2O2, but also sacrifices the stability of catalysts. We present a non‐redox ...hydroxyl‐enriched spinel (CuFe2O4) catalyst with dual Lewis acid sites to realize the homolytic cleavage of H2O2. The results of systematic experiments, in situ characterizations, and theoretical calculations confirm that tetrahedral Cu sites with optimal Lewis acidity and strong electron delocalization can synergistically elongate the O−O bonds (1.47 Å → 1.87 Å) in collaboration with adjacent bridging hydroxyl (another Lewis acid site). As a result, the free energy of H2O2 homolytic cleavage is decreased (1.28 eV → 0.98 eV). H2O2 can be efficiently split into ⋅OH induced by hydroxyl‐enriched CuFe2O4 without MET, which greatly improves the catalyst stability and the H2O2 utilization (65.2 %, nearly 2 times than traditional catalysts). The system assembled with hydroxyl‐enriched CuFe2O4 and H2O2 affords exceptional performance for organic pollutant elimination. The scale‐up experiment using a continuous flow reactor realizes long‐term stability (up to 600 mL), confirming the tremendous potential of hydroxyl‐enriched CuFe2O4 for practical applications.
Macroscopic electron transfer (MET) is indispensable during the traditional H2O2 cleavage process. We demonstrate a non‐redox hydroxyl‐enriched spinel CuFe2O4 with dual Lewis acid sites to realize the homolytic cleavage of H2O2 without MET, which truly promotes H2O2 utilization and the catalyst stability, thereby expanding the applicability of heterogeneous catalysts in environmental remediation and organic synthesis.
Gaussian boson sampling (GBS) is not only a feasible protocol for demonstrating quantum computational advantage, but also mathematically associated with certain graph-related and quantum chemistry ...problems. In particular, it is proposed that the generated samples from the GBS could be harnessed to enhance the classical stochastic algorithms in searching some graph features. Here, we use Jiǔzhāng, a noisy intermediate-scale quantum computer, to solve graph problems. The samples are generated from a 144-mode fully connected photonic processor, with photon click up to 80 in the quantum computational advantage regime. We investigate the open question of whether the GBS enhancement over the classical stochastic algorithms persists-and how it scales-with an increasing system size on noisy quantum devices in the computationally interesting regime. We experimentally observe the presence of GBS enhancement with a large photon-click number and a robustness of the enhancement under certain noise. Our work is a step toward testing real-world problems using the existing noisy intermediate-scale quantum computers and hopes to stimulate the development of more efficient classical and quantum-inspired algorithms.
Ophiolite plays a key role in identifying paleo-ocean and paleo-plate and rebuilding the evolutionary history of ancient orogen. Mafic–ultramafic rocks are distributed in a broadly E–W direction in ...the middle of the Qiangtang terrane, northern Tibetan plateau. However, interpretation of these rocks as ophiolite and subsequent tectonic implications have been much disputed, and they were regarded by some to have an origin in a continental rift setting. A detailed zircon dating and geochemical and Sr–Nd–Hf isotopic study of this suite of rocks has been undertaken in order to clarify this important issue. The mafic–ultramafic suite was collected from the Gangma Co and Guoganjianian localities and is composed of cumulate and isotropic gabbro, basalt, actinolitite and plagiogranite. All basaltic rocks are tholeiitic and have low rare earth element (REE) abundances with variable REE patterns and slight negative Nb and Ti anomalies. These features are comparable with those of normal mid-ocean ridge basalts (N-MORB) and/or enriched mid-ocean ridge basalts (E-MORB). The positive whole-rock εNd(t) and zircon εHf(t) values indicate that these rocks were derived from a long-term depleted mantle source. Zircon U–Pb dating using a sensitive high-resolution ion microprobe (SHRIMP) on two cumulate gabbros and two plagiogranites samples yielded Carboniferous ages of 357±2.5Ma, 356.1±3.0Ma, 354.7±4.7Ma and 345.4±4.6Ma. The ophiolite marks a Paleo-Tethys Ocean basin in middle of the Qiangtang terrane, and it is interpreted as the western extension of the Changning–Menglian Paleo-Tethys ophiolite in the eastern margin of the Tibetan plateau.
► Ophiolitic mélanges occur in the middle of the Qiangtang terrane, northern Tibet. ► These features are comparable with those of N-MORB and/or E-MORB. ► Zircon SHRIMP U–Pb analyses indicate that they were formed in the Early Carboniferous. ► They marked a Paleo-Tethys Ocean basin.
We constructed a novel surface plasmon resonance (SPR) detection assay using carboxyl-functionalized molybdenum disulfide (carboxyl-MoS2) nanocomposites as a signal amplification sensing film for the ...ultrasensitive detection of the lung cancer-associated biomarker cytokeratin 19 fragment (CYFRA21-1). The experiment succeeded in MoS2 reacted with chloroacetic acid giving carboxyl-MoS2 as the reaction product. The additional shoulder in the C 1s and O 1s peaks of carboxyl-MoS2, which were increased in X-ray photoelectron spectroscopy, confirmed the presence of O-C=O groups on the surface of the carboxyl-MoS2. Compared to MoS2, the experimental results confirmed that carboxyl-modified MoS2 had improved low impedance and low refractive index. The carboxyl-MoS2-based chip had a high affinity, with an SPR angle shift enhanced by 2.6-fold and affinity binding K A enhanced by 15-fold compared to a traditional SPR sensor. The results revealed that the carboxyl-MoS2-based chip had high sensitivity, specificity, and SPR signal affinity, while the CYFRA21-1 assay in spiked clinical serum showed a lower detection limit of 0.05 pg/mL and a wider quantitation range (0.05 pg/mL to 100 ng/mL). The carboxyl-MoS2-based chip detection value was about 104 times more sensitive than the limit of detection of an enzyme-linked immunosorbent assay (ELISA) (0.60 ng/mL). The results showed that the carboxyl-MoS2-based chip had the potential to rapidly assay complex samples including bodily fluids, whole blood, serum, plasma, urine, and saliva in SPR-based immunosensors to diagnose diseases including cancer.
In this communication, a single-layer, wideband, differential-fed filtering antenna with high selectivity is proposed. The developed filtering antenna possesses a simple structure and consists of a ...square patch, a square substrate integrated waveguide (SIW) cavity, a pair of symbiotic stepped impedance resonators (SSIRs), and a pair of complementary split ring resonators (CSRRs). The SIW cavity formed with sparse metalized posts is embedded in the square patch, and the impedance bandwidth can be broadened by merging the TM10 mode of the square patch, excited by the electromagnetic energy escaping from the sparse posts, with the TE210 mode in the SIW cavity through differential excitation. The SSIRs are connected with both radiating edges of the square patch. And two extra in-band resonances together with an upper-edge radiation null are simultaneously generated, so the impedance bandwidth and the frequency selectivity at the higher stopband can be significantly improved. The CSRRs, surrounding the differential excitation ports, are etched into the bottom surface of the SIW cavity, and a lower-edge radiation null is produced to further sharpen the roll-off rate. By adjusting the geometrical parameters of the SSIRs and CSRRs, the positions of the two radiation nulls can be independently controlled. For verifying the design method, a prototype of the developed single-layer filtering antenna has been fabricated and tested. The measurement results are well consistent with the simulated values, indicating good performance with a large −10 dB fractional impedance bandwidth of 21.2%, a peak realized gain of 9.3 dBi, two out-of-band rejection levels of more than 26 dB, and very high selectivity.
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