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Inertia-less viscoelastic channel flow displays a supercritical nonnormal mode elastic instability due to finite-size perturbations despite its linear stability. The nonnormal mode instability is determined mainly by a direct transition from laminar to chaotic flow, in contrast to normal mode bifurcation leading to a single fastest-growing mode. At higher velocities, transitions to elastic turbulence and further drag reduction flow regimes occur accompanied by elastic waves in three flow regimes. Here, we demonstrate experimentally that the elastic waves play a key role in amplifying wall-normal vorticity fluctuations by pumping energy, withdrawn from the mean flow, into wall-normal fluctuating vortices. Indeed, the flow resistance and rotational part of the wall-normal vorticity fluctuations depend linearly on the elastic wave energy in three chaotic flow regimes. The higher (lower) the elastic wave intensity, the larger (smaller) the flow resistance and rotational vorticity fluctuations. This mechanism was suggested earlier to explain elastically driven Kelvin–Helmholtz-like instability in viscoelastic channel flow. The suggested physical mechanism of vorticity amplification by the elastic waves above the elastic instability onset recalls the Landau damping in magnetized relativistic plasma. The latter occurs due to the resonant interaction of electromagnetic waves with fast electrons in the relativistic plasma when the electron velocity approaches light speed. Moreover, the suggested mechanism could be generally relevant to flows exhibiting both transverse waves and vortices, such as Alfven waves interacting with vortices in turbulent magnetized plasma, and Tollmien–Schlichting waves amplifying vorticity in both Newtonian and elasto-inertial fluids in shear flows.

Photocatalytic overall water splitting into hydrogen and oxygen is desirable for long-term renewable, sustainable and clean fuel production on earth. Metal sulfides are considered as ideal hydrogen-evolved photocatalysts, but their component homogeneity and typical sulfur instability cause an inert oxygen production, which remains a huge obstacle to overall water-splitting. Here, a distortion-evoked cation-site oxygen doping of ZnIn 2 S 4 (D-O-ZIS) creates significant electronegativity differences between adjacent atomic sites, with S 1 sites being electron-rich and S 2 sites being electron-deficient in the local structure of S 1 –S 2 –O sites. The strong charge redistribution character activates stable oxygen reactions at S 2 sites and avoids the common issue of sulfur instability in metal sulfide photocatalysis, while S 1 sites favor the adsorption/desorption of hydrogen. Consequently, an overall water-splitting reaction has been realized in D-O-ZIS with a remarkable solar-to-hydrogen conversion efficiency of 0.57%, accompanying a ~ 91% retention rate after 120 h photocatalytic test. In this work, we inspire an universal design from electronegativity differences perspective to activate and stabilize metal sulfide photocatalysts for efficient overall water-splitting. Solving component homogeneity and sulfur instability of metal sulfides is crucial for photocatalytic overall water splitting. Here, the authors develop a distortion evoked cation site oxygen doping to create electronegativity differences between adjacent atom and enhance photocatalytic activity

Encapsulation engineering is an effective strategy to improve the stability of perovskite solar cells. However, current encapsulation materials are not suitable for lead-based devices because of their complex encapsulation processes, poor thermal management, and inefficient lead leakage suppression. In this work, we design a self-crosslinked fluorosilicone polymer gel, achieving nondestructive encapsulation at room temperature. Moreover, the proposed encapsulation strategy effectively promotes heat transfer and mitigates the potential impact of heat accumulation. As a result, the encapsulated devices maintain 98% of the normalized power conversion efficiency after 1000 h in the damp heat test and retain 95% of the normalized efficiency after 220 cycles in the thermal cycling test, satisfying the requirements of the International Electrotechnical Commission 61215 standard. The encapsulated devices also exhibit excellent lead leakage inhibition rates, 99% in the rain test and 98% in the immersion test, owing to excellent glass protection and strong coordination interaction. Our strategy provides a universal and integrated solution for achieving efficient, stable, and sustainable perovskite photovoltaics. Encapsulation engineering is an effective strategy to improve the stability of perovskite solar cells. Here, authors design and synthesize self-crosslinked fluorosilicone polymer gel for nondestructive encapsulation at room temperature, and maintain 98% of efficiency after 1000 h in damp heat test.

An addition of long-chain, flexible polymers strongly affects laminar and turbulent Newtonian flows. In laminar inertia-less viscoelastic channel flow, the supercritical elastic instability of non-normal eigenmodes of non-Hermitian equations at finite-size perturbations leads to chaotic flow. Then three chaotic flow regimes: transition, elastic turbulence (ET), and drag reduction (DR), accompanied by elastic waves, are observed and characterized. Here we show that independently of external perturbation strength and structure, chaotic flows above the instability onset in transition, ET, and DR flow regimes reveal similar scaling of flow properties, universal scaling of elastic wave speed with Weissenberg number, Wi , defined the degree of polymer stretching, and the coherent structure of velocity fluctuations, self-organized into cycling self-sustained process, synchronized by elastic waves. These properties persist over the entire channel length above the instability threshold. It means that only an absolute instability exists in inertia-less viscoelastic channel flow, whereas a convective instability, is absent. This unexpected discovery is in sharp contrast with Newtonian flows, where both convective and absolute instabilities are always present in open flows. It occurs due to differences in nonlinear terms in an elastic stress equation, where except for the advective term, two key terms describing polymer stretching along the channel length are present.

To elucidate dynamics and functions in colonic macrophage subsets, and their regulation by ( ) and its associated metabolites in the initiation of colitis-associated colorectal cancer (CAC). Azoxymethane (AOM) and dextran sodium sulfate (DSS) were used to create a CAC model. The tumor-suppressive effect of and variations of macrophage subsets were evaluated. Intestinal macrophages were ablated to determine their role in the protective effects of . Efficacious molecules produced by were identified by non-targeted and targeted liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. The molecular mechanism was further verified in murine bone marrow-derived macrophages (BMDMs), macrophages derived from human peripheral blood mononuclear cells (hPBMCs), and demonstrated in CAC mice. alleviated colitis symptoms, delayed colonic tumorigenesis, and promoted phenotypic differentiation of immature inflammatory macrophages into mature homeostatic macrophages. On the contrary, the ablation of intestinal macrophages largely annulled the protective effects of . Microbial analysis of colonic contents revealed the enrichment of probiotics and the depletion of potential pathogens following supplementation. Moreover, indole-3-lactic acid (ILA) was positively correlated with in CAC mice and highly enriched in the culture supernatant of . Also, the addition of ILA directly promoted AKT phosphorylation and restricted the pro-inflammatory response of murine BMDMs and macrophages derived from hPBMCs . The effects of ILA in murine BMDMs and macrophages derived from hPBMCs were abolished by the aryl hydrocarbon receptor (AhR) antagonist CH-223191 or the AKT inhibitor MK-2206. Furthermore, ILA could protect against tumorigenesis by regulating macrophage differentiation in CAC mice; the AhR antagonist largely abrogated the effects of and ILA in relieving colitis and tumorigenesis. -mediated tryptophan metabolism ameliorates the precancerous inflammatory intestinal milieu to inhibit tumorigenesis by directing the differentiation of immature colonic macrophages.

Single-atom catalysts offer maximal atom utilization efficiencies and high-electronegativity heteroatoms play a crucial role in coordinating reactive single metal atoms to prevent agglomeration. However, these strong coordination bonds withdraw electron density for coordinated metal atoms and consequently affect their catalytic activity. Herein we reveal the high loading (11.3 wt%) and stabilization of moderately coordinated Cu-P 3 structure on black phosphorus support by a photochemical strategy with auxiliary hydrogen. Single-atom Cu sites with an exceptional electron-rich feature show the △ G H * close to zero to favor catalysis. Neighboring Cu atoms work in synergy to lower the energy of key water adsorption and dissociation intermediates. The reported catalyst shows a low overpotential of only 41 mV at 10 mA cm −2 and Tafel slope of 53.4 mV dec −1 for the alkaline hydrogen evolution reaction, surpassing both isolated Cu single atoms and Cu nanoclusters. The promising materials design strategy sheds light on the design and fabrication of high-loading single metal atoms and the role of neighboring single atoms for enhanced reaction kinetics. While atomically dispersed metals can maximize reaction catalytic sites, it is challenging to achieve high atomic densities without agglomeration. Here, authors prepared Cu single-atoms on black phosphorous using a photochemical strategy and auxiliary H 2 as proton reduction electrocatalysts.

Multiple exciton generation (MEG), where two or more electron–hole pairs are produced from the absorption of one high-energy photon, could increase the efficiency of light absorbing devices. However, demonstrations of the effect are still scarce in photocatalytic hydrogen production. Moreover, many photocatalytic systems for overall water splitting suffer from poor charge carrier separation. Here we show that a CdTe quantum dot/vanadium-doped indium sulphide (CdTe/V-In 2 S 3 ) photocatalyst has a built-in electric field and cascade energy band structure sufficient to effectively extract excitons and separate carriers, allowing MEG to be exploited for hydrogen production. We achieve a tunable energy band structure through quantum effects in CdTe and doping engineering of V-In 2 S 3 , which induces a 14-fold enhancement in the CdTe/V-In 2 S 3 interfacial built-in electric field intensity relative to pristine CdTe/V-In 2 S 3 . We report an internal quantum efficiency of 114% at 350 nm for photocatalytic hydrogen production, demonstrating the utilization of MEG effects. The solar-to-hydrogen efficiency is 1.31%. Multiple exciton generation can potentially improve the efficiency of solar-driven devices, but its demonstration for solar fuel production is rare. Here the authors show that quantum efficiencies above 100% are achievable in a water splitting photocatalyst, implying the presence of multiple exciton generation effects.

Magnolol (MG) is one of the primary active components of Magnoliae officinalis cortex, which has been widely used in traditional Chinese and Japanese herbal medicine and possesses a wide range of pharmacological activities. In recent years, attention has been drawn to this component due to its potential as an anti-inflammatory and antitumor drug. To summarize the new biological and pharmacological data on MG, we screened the literature from January 2011 to October 2020. In this review, we provide an actualization of already known anti-inflammatory, cardiovascular protection, antiangiogenesis, antidiabetes, hypoglycemic, antioxidation, neuroprotection, gastrointestinal protection, and antibacterial activities of MG. Besides, results from studies on antitumor activity are presented. We also summarized the molecular mechanisms, toxicity, bioavailability, and formulations of MG. Therefore, we provide a valid cognition of MG.

Single-atom catalysts (SACs) enable atomic-level control over active sites, but orbital-level manipulation to steer catalytic behavior remains challenging. Here, we address this issue through d -orbital engineering of Cu SACs, achieving simultaneous control over coordination geometry (Cu-N 3 ) and high metal loading (33.2 wt%) for direct benzene-to-phenol oxidation with H 2 O 2 . The tri-coordinated Cu SAC (Cu-N 3 -33.2) exhibits the highest performance with 85.8% benzene conversion and a turnover frequency of 680.3 h −1 at 60 o C, ranking it among the best metal-based catalysts. In-situ ATR-IR spectroscopy and DFT calculations reveal that dynamically formed Cu-O intermediates, driven by p-d orbital hybridization between Cu ( d orbitals) and O ( p orbitals), lower the H 2 O 2 activation barrier by 0.98 eV compared to Cu-N 4 sites. High-density atomic Cu sites prevent over-oxidation by consuming singlet oxygen ( 1 O 2 ). This work establishes a dual-parameter optimization paradigm, including orbital configuration and site density, redefining design principles for selective oxidation SACs. Single-atom catalysts provide atomic-level control over active sites but often lack orbital-level manipulation. Here the authors demonstrate orbital engineering of a Cu catalyst, achieving control over coordination geometry and high metal loading.

The electrochemical conversion of nitrate to ammonia is a way to eliminate nitrate pollutant in water. Cu-Co synergistic effect was found to produce excellent performance in ammonia generation. However, few studies have focused on this effect in high-entropy oxides. Here, we report the spin-related Cu-Co synergistic effect on electrochemical nitrate-to-ammonia conversion using high-entropy oxide Mg 0.2 Co 0.2 Ni 0.2 Cu 0.2 Zn 0.2 O. In contrast, the Li-incorporated MgCoNiCuZnO exhibits inferior performance. By correlating the electronic structure, we found that the Co spin states are crucial for the Cu-Co synergistic effect for ammonia generation. The Cu-Co pair with a high spin Co in Mg 0.2 Co 0.2 Ni 0.2 Cu 0.2 Zn 0.2 O can facilitate ammonia generation, while a low spin Co in Li-incorporated MgCoNiCuZnO decreases the Cu-Co synergistic effect on ammonia generation. These findings offer important insights in employing the synergistic effect and spin states inside for selective catalysis. It also indicates the generality of the magnetic effect in ammonia synthesis between electrocatalysis and thermal catalysis. Electrochemical conversion of nitrate into ammonia offers a method for mitigating nitrate pollution in water. Here the authors report the electrochemical nitrate-to-ammonia conversion using high-entropy oxide Mg 0.2 Co 0.2 Ni 0.2 Cu 0.2 Zn 0.2 O and find that the Co spin states are crucial for synergistic ammonia generation.