Light-Emitting Microfibers from Lotus Root for Eco-Friendly Optical Waveguides and Biosensing.

Optical biosensors based on micro/nanofibers are highly valuable for probing and monitoring liquid environments and bioactivity. Most current optical biosensors, however, are still based on glass, semiconductors, or metallic materials, which might not be fully suitable for biologically relevant environments. Here, we introduce biocompatible and flexible microfibers from lotus silk as microenvironmental monitors that exhibit waveguiding of intrinsic fluorescence as well as of coupled light. These features make single-filament monitors excellent building blocks for a variety of sensing functions, including pH probing and detection of bacterial activity. These results pave the way for the development of new and entirely eco-friendly, potentially multiplexed biosensing platforms.

Insights into the spontaneous multi-scale supramolecular assembly in an ionic liquid-based extraction system.

Herein, we report a four-step mechanism for the spontaneous multi-scale supramolecular assembly (MSSA) process in a two-phase system concerning an ionic liquid (IL). The complex ions, elementary building blocks (EBBs), [EBB]n clusters and macroscopic assembly (MA) sphere are formed step by step. The porous large-sized [EBB]n clusters in the glassy state can hardly stay in the IL phase and they transfer to the IL-water interface due to both electroneutrality and amphiphilicity. Then, the clusters undergo random collision in the interface driven by the Marangoni effect and capillary force thereafter. Finally, a single MA sphere can be formed owing to supramolecular interactions. To our knowledge, this is the first example realizing spontaneous whole-process supramolecular assembly covering microscopic, mesoscopic and macroscopic scales in extraction systems. The concept of multi-scale selectivity (MSS) is therefore suggested and its mechanism is revealed. The selective separation and solidification of metal ions can be realized in a MSSA-based extraction system depending on MSS. In addition, insights into the physicochemical characteristics of ILs from microscopic, mesoscopic to macroscopic scales are provided, and especially, the solvation effect of ILs on the large-sized clusters leading to the phase-splitting is examined. It is quite important that the polarization of uranyl in its complex, the growing of uranyl clusters in an IL as well as the glassy material of uranyl are investigated systematically on the basis of both experiment and theoretical calculations in this work.

Coordination of Actinide Single Ions to Deformed Graphdiyne: Strategy on Essential Separation Processes in Nuclear Fuel Cycle.

The coordination of actinides and lanthanides, as well as strontium and cesium with graphdiyne (GDY) was studied experimentally and theoretically. On the basis of experimental results and/or theoretical calculations, it was suggested that Th4+ , Pu4+ , Am3+ , Cm3+ , and Cs+ exist in single-ion states on the special triangular structure of GDY with various coordination patterns, wherein GDY itself is deformed in different ways. Both experiment and theoretical calculations strongly indicate that UO2 2+ , La3+ , Eu3+ , Tm3+ and Sr2+ are not adsorbed by GDY at all. The distinguished adsorption behaviors of GDY afford an important strategy for highly selective separation of actinides and lanthanides, Th4+ and UO2 2+ , and Cs+ and Sr2+ , in the nuclear fuel cycle. Also, the present work sheds light on an approach to explore the unique functions and physicochemical properties of actinides in single-ion states.

Strong Coupling of Folded Phonons with Plasmons in 6H-SiC Micro/Nanocrystals.

Silicon carbide (SiC) has a large number of polytypes of which 3C-, 4H-, 6H-SiC are most common. Since different polytypes have different energy gaps and electrical properties, it is important to identify and characterize various SiC polytypes. Here, Raman scattering is performed on 6H-SiC micro/nanocrystal (MNC) films to investigate all four folded transverse optic (TO) and longitudinal optic (LO) modes. With increasing film thickness, the four folded TO modes exhibit the same frequency downshift, whereas the four folded LO modes show a gradually-reduced downshift. For the same film thickness, all the folded modes show larger frequency downshifts with decreasing MNC size. Based on plasmons on MNCs, these folded modes can be attributed to strong coupling of the folded phonons with plasmons which show different strengths for the different folded modes while changing the film thickness and MNC size. This work provides a useful technique to identify SiC polytypes from Raman scattering.

Enhancement of Ferromagnetism in Nonmagnetic Metal Oxide Nanoparticles by Facet Engineering.

Ferromagnetism in semiconducting metal oxide nanoparticles has been intensively investigated due to their potential applications in spintronics, information storage, and biomedicine. Ferromagnetism can be produced in nonmagnetic metal oxide nanoparticles by a variety of methods or factors, but the saturated magnetization is typically of the order of 10-4 emu g-1 and too small to be useful in practice. In this work, it is demonstrated theoretically and experimentally that stronger ferromagnetism can be achieved in undoped nonmagnetic metal oxide semiconductors by exposing some specific polar crystal facets with carvings of special bonds via the interaction with underlying vacancies. In2 O3 microcubes with completely enclosed {001} polar facets show two orders of magnitude enhancement at room temperature compared to nanoparticles with an irregular morphology. The surface magnetic domains on the {001} facets account for the significantly enhanced ferromagnetism. The technique and concept described here can be extended to other types of metal oxide nanostructures to spur their application to spintronics.

Electrochemiluminescent Spin-Polarized Modulation by Magnetic Ions and Surface Plasmon Coupling.

Electrochemiluminescent modulation: Electrochemiluminescence (ECL) of CdS nanocrystal (NC) film-Au nanoparticle (NP) integrated system is controllably quenched by magnetic Co(2+) ions without external magnetic field owing to spin-polarized modulation of the electron-hole recombination caused by ferromagnetic alignment of Co(2+) in close proximity to Au NPs.

Strong Facet-Induced and Light-Controlled Room-Temperature Ferromagnetism in Semiconducting ß-FeSi2 Nanocubes.

Crystalline ß-FeSi2 nanocubes with two {100} facets and four {011} lateral facets synthesized by spontaneous one-step chemical vapor deposition exhibit strong room-temperature ferromagnetism with saturation magnetization of 15 emu/g. The room-temperature ferromagnetism is observed from the ß-FeSi2 nanocubes larger than 150 nm with both the {100} and {011} facets. The ferromagnetism is tentatively explained with a simplified model including both the itinerant electrons in surface states and the local moments on Fe atoms near the surfaces. The work demonstrates the transformation from a nonmagnetic semiconductor to a magnetic one by exposing specific facets and the room-temperature ferromagnetism can be manipulated under light irradiation. The semiconducting ß-FeSi2 nanocubes may have large potential in silicon-based spintronic applications.

Dephasing and dissipation in a source-drain model of light-harvesting systems.

The energy transport process in natural-light-harvesting systems is investigated by solving the time-dependent Schrödinger equation for a source-network-drain model incorporating the effects of dephasing and dissipation, owing to coupling with the environment. In this model, the network consists of electronically coupled chromophores, which can host energy excitations (excitons) and are connected to source channels, from which the excitons are generated, thereby simulating exciton creation from sunlight. After passing through the network, excitons are captured by the reaction centers and converted into chemical energy. In addition, excitons can reradiate in green plants as photoluminescent light or be destroyed by nonphotochemical quenching (NPQ). These annihilation processes are described in the model by outgoing channels, which allow the excitons to spread to infinity. Besides the photoluminescent reflection, the NPQ processes are the main outgoing channels accompanied by energy dissipation and dephasing. From the simulation of wave-packet dynamics in a one-dimensional chain, it is found that, without dephasing, the motion remains superdiffusive or ballistic, despite the strong energy dissipation. At an increased dephasing rate, the wave-packet motion is found to switch from superdiffusive to diffusive in nature. When a steady energy flow is injected into a site of a linear chain, exciton dissipation along the chain, owing to photoluminescence and NPQ processes, is examined by using a model with coherent and incoherent outgoing channels. It is found that channel coherence leads to suppression of dissipation and multiexciton super-radiance. With this method, the effects of NPQ and dephasing on energy transfer in the Fenna-Matthews-Olson complex are investigated. The NPQ process and the photochemical reflection are found to significantly reduce the energy-transfer efficiency in the complex, whereas the dephasing process slightly enhances the efficiency. The calculated absorption spectrum reproduces the main features of the measured counterpart. As a comparison, the exciton dynamics are also studied in a linear chain of pigments and in a multiple-ring system of light-harvesting complexes II (LH2) from purple bacteria by using the Davydov D1 ansatz. It is found that the exciton transport shows superdiffusion characteristics in both the chain and the LH2 rings.

Size-dependent magnetic order and giant magnetoresistance in organic titanium-benzene multidecker cluster.

Using density functional theory and non-equilibrium Green's function method, we investigated the magnetic and transport properties of small organic titanium-benzene sandwich clusters TinBzn+1 (n = 1-3). The results show that TiBz2 is nonmagnetic while Ti2Bz3 and Ti3Bz4 are ferromagnetic, and our prediction is in agreement with experimental observation. The double exchange mechanism plays a key role in the ferromagnetism of larger clusters. With Ni as the two electrodes, significant spin-filter efficiency (SFE) and giant magnetoresistance (GMR) were found in the TinBzn+1 molecular junction. These transport properties could be controlled by cluster size, bias voltage or gate voltage. Specially, a sign-reversible GMR effect was observed in the Ti2Bz3 molecular junction. Finally, the microscopic mechanisms of SFE and GMR were suggested.

Optical color routing enabled by deep learning.

Nano-color routing has emerged as an immensely popular and widely discussed subject in the realms of light field manipulation, image sensing, and the integration of deep learning. The conventional dye filters employed in commercial applications have long been hampered by several limitations, including subpar signal-to-noise ratio, restricted upper bounds on optical efficiency, and challenges associated with miniaturization. Nonetheless, the advent of bandpass-free color routing has opened up unprecedented avenues for achieving remarkable optical spectral efficiency and operation at sub-wavelength scales within the area of image sensing applications. This has brought about a paradigm shift, fundamentally transforming the field by offering a promising solution to surmount the constraints encountered with traditional dye filters. This review presents a comprehensive exploration of representative deep learning-driven nano-color routing structure designs, encompassing forward simulation algorithms, photonic neural networks, and various global and local topology optimization methods. A thorough comparison is drawn between the exceptional light-splitting capabilities exhibited by these methods and those of traditional design approaches. Additionally, the existing research on color routing is summarized, highlighting a promising direction for forthcoming development, delivering valuable insights to advance the field of color routing and serving as a powerful reference for future endeavors.

Cordyceps militaris Extract and Cordycepin Alleviate Oxidative Stress, Modulate Gut Microbiota and Ameliorate Intestinal Damage in LPS-Induced Piglets.

Cordycepin is considered a major bioactive component in Cordyceps militaris extract. This study was performed to evaluate the ameliorative effect of Cordyceps militaris extract (CME) and cordycepin (CPN) supplementation on intestinal damage in LPS-challenged piglets. The results showed that CPN or CME supplementation significantly increased the villus height (p < 0.01) and villus height/crypt depth ratio (p < 0.05) in the jejunum and ileum of piglets with LPS-induced intestinal inflammation. Meanwhile, CPN or CME supplementation alleviated oxidative stress and inflammatory responses by reducing the levels of MDA (p < 0.05) and pro-inflammatory cytokines in the serum. Additionally, supplementation with CPN or CME modulated the structure of the intestinal microbiota by enriching short-chain fatty acid-producing bacteria, and increased the level of butyrate (p < 0.05). The RNA-seq results demonstrated that CME or CPN altered the complement and coagulation-cascade-related genes (p < 0.05), including upregulating gene KLKB1 while downregulating the genes CFD, F2RL2, CFB, C4BPA, F7, C4BPB, CFH, C3 and PROS1, which regulate the complement activation involved in inflammatory and immune responses. Correlation analysis further demonstrated the potential relation between the gut microbiota and intestinal inflammation, oxidative stress, and butyrate in piglets. In conclusion, CPN or CME supplementation might inhibit LPS-induced inflammation and oxidative stress by modulating the intestinal microbiota and its metabolite butyrate in piglets.

Improvement on the Radiation Stability of Multi-scale Supramolecular Assembly in Ionic Liquid-Based Extraction.

The multi-scale supramolecular assembly (MSSA)-based extraction strategy with hydroxyl-functionalized ionic liquid (IL) is promising in the separation of metal ions from radioactive environments for which a comprehensive understanding toward the radiation stability of the MSSA system is necessary. Herein, we report on the analyses of the radiation stability of MSSA in extraction, especially the adopted ILs 1-(2-hydroxyethyl)-3-methylimidazolium bis(trifluoromethylsulfonyl) imide (IL-1) and 1-(2-hydroxyethyl)-2,3-dimethylimidazolium bis(trifluoromethylsulfonyl) imide (IL-2), by UV-vis, 1H NMR, and ESI-HRMS. It was found that the macroscopic assembly (MA) sphere could not be formed after γ irradiation on the extraction system with IL-1. On the contrary, the trisubstituted IL-2 instead of the disubstituted IL-1 remarkably improved the radiation stability of the MSSA system to guarantee the formation of the MA sphere. The high extraction efficiency could be kept, and the mechanism of such an improvement was revealed.

Retinol dehydrogenase 10 reduction mediated retinol metabolism disorder promotes diabetic cardiomyopathy in male mice.

Diabetic cardiomyopathy is a primary myocardial injury induced by diabetes with complex pathogenesis. In this study, we identify disordered cardiac retinol metabolism in type 2 diabetic male mice and patients characterized by retinol overload, all-trans retinoic acid deficiency. By supplementing type 2 diabetic male mice with retinol or all-trans retinoic acid, we demonstrate that both cardiac retinol overload and all-trans retinoic acid deficiency promote diabetic cardiomyopathy. Mechanistically, by constructing cardiomyocyte-specific conditional retinol dehydrogenase 10-knockout male mice and overexpressing retinol dehydrogenase 10 in male type 2 diabetic mice via adeno-associated virus, we verify that the reduction in cardiac retinol dehydrogenase 10 is the initiating factor for cardiac retinol metabolism disorder and results in diabetic cardiomyopathy through lipotoxicity and ferroptosis. Therefore, we suggest that the reduction of cardiac retinol dehydrogenase 10 and its mediated disorder of cardiac retinol metabolism is a new mechanism underlying diabetic cardiomyopathy.

Long-term statins administration exacerbates diabetic nephropathy via ectopic fat deposition in diabetic mice.

Statins play an important role in the treatment of diabetic nephropathy. Increasing attention has been given to the relationship between statins and insulin resistance, but many randomized controlled trials confirm that the therapeutic effects of statins on diabetic nephropathy are more beneficial than harmful. However, further confirmation of whether the beneficial effects of chronic statin administration on diabetic nephropathy outweigh the detrimental effects is urgently needed. Here, we find that long-term statin administration may increase insulin resistance, interfere with lipid metabolism, leads to inflammation and fibrosis, and ultimately fuel diabetic nephropathy progression in diabetic mice. Mechanistically, activation of insulin-regulated phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin signaling pathway leads to increased fatty acid synthesis. Furthermore, statins administration increases lipid uptake and inhibits fatty acid oxidation, leading to lipid deposition. Here we show that long-term statins administration exacerbates diabetic nephropathy via ectopic fat deposition in diabetic mice.

Low-frequency Raman scattering of bioinspired self-assembled diphenylalanine nanotubes/microtubes.

Low-frequency Raman scattering from self-assembled bioinspired diphenylalanine (FF) nanotubes/microtubes (NTs/MTs) has been observed for the first time. Four double peaks are identified as the three-dimensional localized collective (acoustic phonon) vibrations of FF molecules in the subnanometer crystalline structure (biological building block) forming the FF NTs/MTs. The increased energy separations between two subpeaks caused by the loss of water in the nanochannel cores are due to the enhancement of vibrational couplings between the FF molecules as a result of the reduction of the influence from water on the coupling. The results provide experimental evidence of localized but still weakly coupled vibrations in organic crystalline nanostructures in the low-frequency region.

Enhancement of coherent energy transport by disorder and temperature in light harvesting processes.

We investigate the influence of static disorder and thermal excitations on excitonic energy transport in the light-harvesting apparatus of photosynthetic systems by solving the Schrödinger equation and taking into account the coherent hoppings of excitons, the rates of exciton creation and annihilation in antennas and reaction centers, and the coupling to thermally excited phonons. The antennas and reaction centers are modeled, respectively, as the sources and drains which provide the channels for creation and annihilation of excitons. Phonon modes below a maximum frequency are coupled to the excitons that are continuously created in the antennas and depleted in the reaction centers, and the phonon population in these modes obeys the Bose-Einstein distribution at a given temperature. It is found that the energy transport is not only robust against the static disorder and the thermal noise, but it can also be enhanced by increasing the randomness and temperature in most parameter regimes. Relevance of our work to the highly efficient energy transport in photosynthetic systems is discussed.

Effects of water molecules on photoluminescence from hierarchical peptide nanotubes and water probing capability.

Photoluminescence (PL) spectra reveal that deficiency of water molecules in the channel cores of bioinspired hierarchical diphenylalanine ( L -Phe- L -Phe, FF) peptide nanotubes (PNTs) not only modifies the bandgap of the subnanometer crystalline structure formed by the self-assembly process, but also induces a characteristic ultraviolet PL peak the position of which is linearly proportional to the number of water molecules in the PNTs. Addition or loss of water molecules gives rise to the UV PL redshift or blueshift. Density functional theory calculation also confirms that addition of water molecules to the PNTs causes splitting of the valence-band peak, which corresponds to the shift and splitting of the observed UV PL peak. Water molecules play an important role in the biological properties of FF PNTs and the results demonstrate that the PL spectra can be used to probe the number of water molecules bonded to the FF molecules.

Construction and application of a dual promoter system for efficient protein production and metabolic pathway enhancement in Bacillus licheniformis.

Promoter plays the critical role in regulating gene transcription, and dual-promoter has received the widespread attentions due to its high efficiency and continuity, here, we want to construct an efficient dual-promoter for protein production and metabolic pathway enhancement. Firstly, our results indicated that P43 promoter efficiently transcribed at logarithmic period, while the σB-type promoters (PylB, PgsiB, PykzA) were active at stationary phase. Then, several dual promoters were constructed by coupling these σB-type promoters with P43, and the attained dual-promoter PykzA-P43 showed the best performance, which led to 1.72-, 3.46- and 1.85-fold increases of green fluorescence intensity, red fluorescence intensity and α-amylase activity, compared with those of the recognized strong promoter P43, respectively. Furthermore, α-amylase activity was further increased to 389.65 U/mL by 32.20 % via optimizing sigma factor binding sites (-10 and -35 boxes) of PykzA-P43, attaining the optimized dual promoter Pdual3. Finally, Pdual3 was applied in metabolic pathway enhancement, and the yields of Poly γ-glutamic acid, acetoin and 2, 3-butanediol were respectively improved by 82.01 %, 17.09 % and 99.39 %. Our results indicated that dual-promoter significantly enhanced gene expression, and this study provided an energetic dual-promoter Pdual3 for efficient protein production and metabolic pathway enhancement in Bacillus licheniformis.

Controlling Electron Spin Decoherence in Nd-based Complexes via Symmetry Selection.

Long decoherence time is a key consideration for molecular magnets in the application of the quantum computation. Although previous studies have shown that the local symmetry of spin carriers plays a crucial part in the spin-lattice relaxation process, its role in the spin decoherence is still unclear. Herein, two nine-coordinated capped square antiprism neodymium moieties [Nd(CO3)4H2O]5- with slightly different local symmetries, C1 versus C4 (1 and 2), are reported, which feature in the easy-plane magnetic anisotropy as shown by the high-frequency electron paramagnetic resonance (HF-EPR) studies. Detailed analysis of the relaxation time suggests that the phonon bottleneck effect is essential to the magnetic relaxation in the crystalline samples of 1 and 2. The 240 GHz Pulsed EPR studies show that the higher symmetry results in longer decoherence times, which is supported by the first principle calculations.

Violation of the single-parameter scaling hypothesis in human chromosome 22 with charge transfer models.

We investigate transport properties of DNA sequences in human chromosome 22 and compare the results with those of a random artificial DNA sequence based on the single- and double-stranded charge transfer models. The statistical quantities, including the Hurst exponent, the distribution of Lyapunov exponent (LE), the central moments, and the scaling parameter, are numerically calculated by using the transfer-matrix approach. It is found that the existence of satellite DNA segments in human chromosome 22 could result in deviations from usual Gaussian distribution of LE. Our results suggest that the presence of the satellite DNA segments, together with the long-range correlations and the base-pairing correlations could lead to the violation of single-parameter scaling hypothesis which holds for the random artificial DNA sequence although the behaviors of the averaged LEs for both DNA sequences are similar. This provides a viewpoint to analyze differences between the genomic DNA sequences and the nonliving random ones on the basis of localization properties of wave functions in the sequences.