High Verdet constant of Tb2O3-doped TiO-B2O3-Al2O3-Na2O magneto-optical glass.

Tb-doped magneto-optical (MO) glass is widely used in fiber optics, optical isolators, and modulators. However, only the paramagnetic Tb3+ ions exhibit significant MO effects, whereas the diamagnetism Tb4+ ions suppress the MO effects. Therefore, the valence state control of Tb ions is very critical to optimize MO performance. Here, a reduction strategy was introduced to adjust the Tb valence in glass to achieve the high MO effect. The TiO, which has low valence Ti2+ ions and good reducibility, was used to suppress the oxidation of Tb3+ to Tb4+ ions. In the TiO-B2O3-Al2O3-Na2O glass, 10 mol% TiO can increase the Verdet constant at 650 nm by 19%. With the further increase in Tb2O3 concentration, the Verdet constant reaches a high value of 117 rad/(T·m) at 650 nm, which is close to the Verdet constant of TGG crystal (121 rad/(T·m)). This work provides a new approach to increase the Verdet constant of MO glass.

Infrared Evanescent Wave Sensing Based on a Ge10As30Se40Te20 Fiber for Alcohol Detection.

Infrared evanescent wave sensing based on chalcogenide fiber is an emerging technology for qualitative and quantitative analysis of most organic compounds. Here, a tapered fiber sensor made from Ge10As30Se40Te20 glass fiber was reported. The fundamental modes and intensity of evanescent waves in fibers with different diameters were simulated with COMSOL. The 30 mm length tapered fiber sensors with different waist diameters, 110, 63, and 31 µm, were fabricated for ethanol detection. The sensor with a waist diameter of 31 µm has the highest sensitivity of 0.73 a.u./% and a limit of detection (LoD) of 0.195 vol.% for ethanol. Finally, this sensor has been used to analyze alcohols, including Chinese baijiu (Chinese distilled spirits), red wine, Shaoxing wine (Chinese rice wine), Rio cocktail, and Tsingtao beer. It is shown that the ethanol concentration is consistent with the nominal alcoholicity. Moreover, other components such as CO2 and maltose can be detected in Tsingtao beer, demonstrating the feasibility of its application in detecting food additives.

Facile Melting-Crystallization Synthesis of Cs2NaxAg1-xInCl6: Bi Double Perovskites for White Light-Emitting Diodes.

Lead-free double perovskites (DPs) have outstanding luminescent properties, which make them excellent candidates for wide use in optoelectronics. Herein, a solvent-free melting-crystallization technique, which can produce kilogram-scale DP microcrystals (DP-MCs) in one batch, is invented to synthesize the Cs2NaxAg1-xInCl6: Bi (x = 0, 0.2, 0.4, 0.6, 0.8, and 1) DP-MCs. The structure and composition analysis confirmed the products are pure Cs2NaxAg1-xInCl6 DP-MCs. Affected by Jahn-Teller distortion of AgCl6 octahedra, self-trapped excitons appear in the excited state, resulting in the broadband emission (400-850 nm) of Cs2Ag1-xNaxInCl6: Bi DP-MCs. The enhancement of the photoluminescence quantum yield can be realized by introducing Na+ to break the parity-forbidden transition in the Cs2AgInCl6 DP. Optimized Cs2Na0.4Ag0.6InCl6: Bi DP-MC phosphors combined with commercial blue and green phosphors were coated on ultraviolet chips (365 nm) to fabricate white light-emitting diodes (WLEDs) from warm white (2930 K) to cold white (6957 K). An ultrahigh color rendering index of 97.1 and a CCT of 5548 K as well as Commission Internationale de l'Eclairage color coordinates of (0.331, 0.339) have been demonstrated. This kilogram-scale synthesis technique could stimulate the industrial development of WLEDs for general lighting based on DP-MC phosphors.

Changes of gut microbiota during silybin-mediated treatment of high-fat diet-induced non-alcoholic fatty liver disease in mice.

AIM: Gut microbiota are involved in the pathogenesis of non-alcoholic fatty liver disease (NAFLD). Silybin (Sil), a naturally occurring hepatoprotective agent, is widely used for treating NAFLD. Whether Sil affects gut microbiota during its actions in treating NAFLD is unknown. We aimed to examine the effect of Sil on intestinal flora dysbiosis induced by a high-fat diet (HFD). METHODS: After 10 weeks of feeding normal chow diet or HFD, mice were given a daily gavage for 8 weeks. Cecal contents were harvested for study of short-chain fatty acids, bile acids, and gut microbiota alteration. RESULTS: Sil showed protective effects against dietary-induced obesity and liver steatosis; accordingly, gut microbiota composition changed. At the phylum level, compared with the HFD group, mice in the Sil-treated group had significantly lower levels of Firmicutes, and the ratio of Firmicutes-to-Bacteroidetes was lower (P < 0.05). At the genus level, the Sil-treated group have significantly lower levels of Lachnoclostridium, Lachnospiraceae_UCG-006, and Mollicutes_RF9, which were reported to be potentially related to diet-induced obesity, and increased levels of Blautia (P < 0.05), Akkermansia (P < 0.05), and Bacteroides (P < 0.05), which are known to have a beneficial effect on improving NAFLD. Sil also showed an inhibitory effect on well-known beneficial bacteria, such as Alloprevotella and Lactobacillus. Furthermore, the production of acetate, propionate, and butyrate increased, whereas the generation of formate and conversion of cytotoxic secondary metabolites (lithocholic acid and deoxy-cholic acid) decreased in mice treated with Sil. CONCLUSIONS: Sil might have beneficial effects on ameliorating NAFLD and mediating HFD-induced change of gut microbiota composition, followed by major changes in secondary metabolites, such as short-chain fatty acids and bile acids.

A ratiometric fluorescent probe for determination of the anthrax biomarker 2,6-pyridinedicarboxylic acid based on a terbium(III)- functionalized UIO-67 metal-organic framework.

Terbium(III)-functionalized zirconium-based MOFs (Tb3+@UIO-67) were synthesized by doping Tb3+ into UIO-67 using a post-synthetic modification. The Tb3+@UIO-67 (solid or aqueous dispersion) shows only blue fluorescence (emission peaks at 420 nm) under an ultraviolet lamp (254 nm). Upon addition of 2,6-pyridinedicarboxylic acid (DPA; an anthrax biomarker), the color of the Tb3+@UIO-67 aqueous dispersion under an ultraviolet lamp changes from blue to green. This is mainly because DPA has a good sensitization effect on Tb3+. DPA can be determined by measurement of the ratio of the fluorescence intensities at 544 nm and 420 nm (excitation at 278 nm). The method allows DPA to be detected in the 0.3 to 6 µM concentration range, with a detection limit of 36 nM. Graphical abstract Schematic representation of a ratiometric fluorescent probe synthesized by doping terbium ions into a zirconium-based MOF (UIO-67) for determination of an anthrax biomarker.

In situ and ex-situ physical scenario of the femtosecond laser-induced periodic surface structures.

Laser-induced periodic surface structures (LIPSS) are a universal phenomenon that can allow tailoring nanoelectronics and nanophotonics devices. However, there is an issue about the formation mechanism of LIPSS, and the current research mainly focuses on the formation process of the individual structures, such as the low spatial frequency LIPSS (LSFL), sub-wavelength structures, and laser-induced periodic annular surface structures (LIPASS). A whole process formation picture of the series of these periodic structures is still missing. In this study, a pump-probing setup is applied to ensure the real-time and in situ monitoring of surface modification under different pulse numbers. LSFL firstly appears on the surface after two laser shots, and then, laser-induced orthogonal periodic structures (LIOPS) become the dominant morphology after five laser shots, which result from the local field enhancement of the surface ripples. As the laser shots increase, the LSFL split leads to the formation of nanopillars, and the formation of the nanopillars under the surface LSFL (after ten laser shots) is due to the transition between the LSFL and HSFL with an orientation parallel to the laser polarization. A dip surrounded by annular periodic fringes after 50 laser shots is observed, which is due to the interference of the incident laser field and the reflected laser field on the crater surface. Finally, a direct writing technique for fabrication of nano-gratings is also reported.

Raman gain and femtosecond laser induced damage of Ge-As-S chalcogenide glasses.

Chemical stoichiometric Ge-As-S glasses were prepared, and their thermal properties, refractive index (n), optical bandgap, Raman gain, and femtosecond laser damage were examined. Results revealed that the n and density (ρ) of the glasses decreased as Ge concentration increased, whereas the bandgap and glass transition temperature (Tg) increased. The Raman gain coefficients (gR) of the samples were calculated on the basis of spontaneous Raman scattering spectra. gR decreased from 2.79 × 10-11 m/W for As2S3 to 1.06 × 10-11 m/W for GeS2 as Ge concentration increased. However, the smallest gR was 100 times higher than that of fused silica (0.89 × 10-13 m/W). When these glasses were irradiated by a laser with a pulse width of 150 fs and a power of 33 mW at 3 µm, the damaged area and depth decreased and the damage threshold increased gradually as Ge concentration increased. Raman spectra and composition analysis indicated that surface oxidation probably occurred and sulfur gasified at a high laser power. Although the gR decreased as Ge was added, the laser damage threshold of Ge-As-S glasses was higher than that of the As2S3 glass. Thus, these glasses are potential materials for Raman gain media.

Mid-infrared optical nonlinearities of chalcogenide glasses in Ge-Sb-Se ternary system.

Optical nonlinearities of chalcogenide glasses in the Ge-Sb-Se ternary system are investigated at mid-infrared wavelengths (2000 and 2500 nm) with femtosecond Z-scan technique. Strong nonlinear refraction in the chalcogenide glasses is observed at 2000 nm, due to three-photon absorption resonance. In addition, the variation in the nonlinear refraction (γ) of the Ge-Sb-Se glasses shows two jumpoints as mean co-ordination number (MCN) approaches 2.4 or 2.7, consistent with the theoretical predication.

Fabrication and characterization of multimaterial chalcogenide glass fiber tapers with high numerical apertures.

This paper reports on the fabrication and characterization of multimaterial chalcogenide fiber tapers that have high numerical apertures (NAs). We first fabricated multimaterial As(2)Se(3)-As(2)S(3) chalcogenide fiber preforms via a modified one-step coextrusion process. The preforms were drawn into multi- and single-mode fibers with high NAs (≈1.45), whose core/cladding diameters were 103/207 and 11/246 µm, respectively. The outer diameter of the fiber was tapered from a few hundred microns to approximately two microns through a self-developed automatic tapering process. Simulation results showed that the zero-dispersion wavelengths (ZDWs) of the tapers were shorter than 2 µm, indicating that the tapers can be conveniently pumped by commercial short wavelength infrared lasers. We also experimentally demonstrated the supercontinuum generation (SCG) in a 15-cm-long multimaterial As(2)Se(3)-As(2)S(3) chalcogenide taper with 1.9 µm core diameter and the ZDW was shifted to 3.3 µm. When pumping the taper with 100 fs short pulses at 3.4 µm, a 20 dB spectral of the generated supercontinuum spans from 1.5 µm to longer than 4.8 µm.

Quantum cutting in Pr3+-Yb3+ codoped chalcohalide glasses for high-efficiency c-Si solar cells.

Downconversion materials, which can convert one high-energy photon to two low-energy photons, have provided a promising avenue for the enhancement of solar cell efficiency. In this work, the Pr3+-Yb3+ codoped 25GeS2-35Ga2S3-40CsCl chalcohalide glasses were synthesized in a vacuumed silica ampoule by the melting-quenching technique. Under 474 nm excitation, the visible and near-IR emission spectra reveal the energy transfer from Pr3+ to Yb3+ ions, resulting in the intense 1008 nm near-IR emission for the c-Si solar cells. By tuning the excitation laser power, it is determined that one visible photon has been cut into two near-IR photons during the energy transfer process. With the help of an integrated sphere, the real quantum yields of near-IR emissions were calculated. For the 0.2Pr2S3-0.2Yb2S3 (in mol.%) codoped chalcohalide glass, the quantum yield equals 10.8%. Although this efficiency is still low, this result will open a new route to realize the efficient spectral modification of the solar spectrum.

Covalent drugs based on small molecules and peptides for disease theranostics.

Biomacromolecules, such as proteins, nucleic acids and polysaccharides, are widely distributed in the human body, and some of them have been recognized as the targets of drugs for disease theranostics. Drugs typically act on targets in two ways: non-covalent bond and covalent bond. Non-covalent bond-based drugs have some disadvantages, such as structural instability and environmental sensitivity. Covalent interactions between drugs and targets have a longer action time, higher affinity and controllability than non-covalent interactions of conventional drugs. With the development of artificial intelligence, covalent drugs have received more attention and have been developed rapidly in pharmaceutical research in recent years. From the perspective of covalent drugs, this review summarizes the design methods and the effects of covalent drugs. Finally, we discuss the application of covalent peptide drugs and expect to provide a new reference for cancer treatment.

Ultrafast Knock-Off Li+ Diffusion and Subtle Structural Evolution of Li5V3O8 Anode in Lithium-Ion Batteries.

Li5V3O8, a lithiation product derived from the LiV3O8 cathode, has emerged as a promising intercalation-type anode material, boasting a theoretical capacity of 256 mA h g-1. Through a comprehensive combination of experimental and theoretical approaches, we demonstrate its capability to intercalate a substantial amount of Li+ at extremely high rates. Experimental findings reveal that Li5V3O8 exhibits outstanding high-rate capability (with a specific capacity of 152 mA h g-1, 60% of the theoretical capacity at 40 C) and exceptional cyclability (with a capacity retention of 80% after 11,000 cycles at 20 C). The structural changes in Li5V3O8 during the lithiation/delithiation cycles are subtle and reversible. First-principles calculations highlight a knock-off mechanism in Li+ diffusion within Li5V3O8, with an estimated energy barrier ranging from 0.16 to 0.38 eV, considerably lower than that of a direct hopping mechanism (0.62-1.44 eV). These ultrafast ion diffusion properties are attributed to interlock interactions among interstitial tetrahedral Li+ and neighboring octahedral lattice Li+, facilitating long-distance and chain-like Li+ diffusion. This study not only introduces an influential vanadium-based anode material with practical implications for fast-charging lithium-ion batteries but also provides fundamental insights into solid state Li+ diffusion kinetics.

Double Perovskite Single Crystals with High Laser Irradiation Stability for Solid-State Laser Lighting and Anti-counterfeiting.

Laser lighting devices, comprising an ultraviolet (UV) laser chip and a phosphor material, have emerged as a highly efficient approach for generating high-brightness light sources. However, the high power density of laser excitation may exacerbate thermal quenching in conventional polycrystalline or amorphous phosphors, leading to luminous saturation and the eventual failure of the device. Here, for the first time, we raise a single-crystal (SCs) material for laser lighting considering the absence of grain boundaries that scatter electrons and phonons, achieving high thermal conductivity (0.81 W m-1 K-1) and heat-resistance (575 °C). The SCs products exhibit a high photoluminescence quantum yield (89%) as well as excellent stability toward high-power lasers (>12.41 kW/cm2), superior to all previously reported amorphous or polycrystalline matrices. Finally, the laser lighting device was fabricated by assembling the SC with a UV laser chip (50 mW), and the device can maintain its performance even after continuous operation for 4 h. Double perovskite single crystals doped with Yb3+/Er3+ demonstrated multimodal luminescence with the irradiation of 355 and 980 nm lasers, respectively. This characteristic holds significant promise for applications in spectrally tunable laser lighting and multimodal anticounterfeiting.

Stereo-Hindrance Engineering of A Cation toward <110>-Oriented 2D Perovskite with Minimized Tilting and High-Performance X-Ray Detection.

2D <100>-oriented Dion-Jacobson or Ruddlesden-Popper perovskites are widely recognized as promising candidates for optoelectronic applications. However, the large interlayer spacing significantly hinders the carrier transport. <110>-oriented 2D perovskites naturally exhibit reduced interlayer spacings, but the tilting of metal halide octahedra is typically serious and leads to poor charge transport. Herein, a <110>-oriented 2D perovskite EPZPbBr4 (EPZ = 1-ethylpiperazine) with minimized tilting is designed through A-site stereo-hindrance engineering. The piperazine functional group enters the space enclosed by the three [PbBr6]4- octahedra, pushing Pb─Br─Pb closer to a straight line (maximum Pb─Br─Pb angle ≈180°), suppressing the tilting as well as electron-phonon coupling. Meanwhile, the ethyl group is located between layers and contributes an extremely reduced effective interlayer distance (2.22 Å), further facilitating the carrier transport. As a result, EPZPbBr4 simultaneously demonstrates high µτ product (1.8 × 10-3 cm2 V-1) and large resistivity (2.17 × 1010 Ω cm). The assembled X-ray detector achieves low dark current of 1.02 × 10-10 A cm-2 and high sensitivity of 1240 µC Gy-1 cm-2 under the same bias voltage. The realized specific detectivity (ratio of sensitivity to noise current density, 1.23 × 108 µC Gy-1 cm-1 A-1/2) is the highest among all reported perovskite X-ray detectors.

Growth mechanism of metal halide perovskite single crystals in solution.

Metal halide perovskite (MHP) single crystals (SCs) have been demonstrated to have significant potential in photodetectors and photovoltaic devices due to their exceptional optoelectronic properties. The most promising approach for large-scale fabrication of high-quality MHP SCs is the synthesis of MHP SCs in solution. To explain the mechanism and guide the crystal growth process, the classical nucleation-growth theory was established. However, it mainly focuses on zone melting systems and does not account for the interaction between perovskite and solvent. In this review, we specifically focus on the difference in the growth mechanism between MHP SCs in solution and traditional SCs synthesized by the melting method, which includes a discussion of the dissolution, nucleation, and growth processes. We then summarize recent advances in the preparation of MHP SCs based on the special growth mechanism of the perovskite system. The purpose of this review is to provide comprehensive information to offer targeted theoretical guidance as well as unified understanding for the preparation of high-quality MHP SCs in solution.

High Refractive Index GRIN Lens for IR Optics.

Infrared gradient refractive index (GRIN) material lenses have attracted much attention due to their continuously varying refractive index as a function of spatial coordinates in the medium. Herein, a glass accumulation thermal diffusion method was used to fabricate a high refractive index GRIN lens. Six Ge17.2As17.2SexTe(65-x) (x = 10.5-16) glasses with good thermal stability and high refractive index (n@10 µm > 3.1) were selected for thermal diffusion. The refractive index span (∆n) of 0.12 was achieved in this GRIN lens. After thermal diffusion, the lens still had good transmittance (45%) in the range of 8-12 µm. Thermal imaging confirmed that this lens can be molded into the designed shape. The refractive index profile was indirectly characterized by the structure and composition changes. The structure and composition variation became linear with the increase in temperature from 260 °C to 270 °C for 12 h, indicating that the refractive index changed linearly along the axis. The GRIN lens with a high refractive index could find applications in infrared optical systems and infrared lenses for thermal imaging.

Cell membrane-specific self-assembly of peptide nanomedicine induces tumor immunogenic death to enhance cancer therapy.

Immunogenic cell death (ICD), as an unusual cell death pattern, mediates cancer cells to release a series of damage-associated molecular patterns (DAMPs), and is widely used in the field of cancer immunotherapy. Injuring the cell membrane can serve as a novel ICD initiation strategy. In this study, a peptide nanomedicine (PNpC) is designed using the fragment CM11 of cecropin, which is effective in disrupting cell membranes because of its α-helical structure. PNpC self-assembles in situ in the presence of high levels of alkaline phosphatase (ALP) on the tumor cell membrane, transforming from nanoparticles to nanofibers, which reduces the cellular internalization of the nanomedicine and increases the interaction between CM11 and tumor cell membranes. Both in vitro and in vivo results indicate that PNpC plays a significant role in killing tumor cells by triggering ICD. The ICD induced by the destruction of the cancer cell membrane is accompanied by the release of DAMPs, which promotes the maturation of DCs and facilitates the presentation of tumor-associated antigens (TAA), resulting in the infiltration of CD8+ T cells. We believe that PNpC can trigger ICD while killing cancer cells, providing a new reference for cancer immunotherapy.

Effect of Se on Structure and Electrical Properties of Ge-As-Te Glass.

The Ge-As-Te glass has a wide infrared transmission window range of 3-18 µm, but its crystallization tendency is severe due to the metallicity of the Te atom, which limits its development in the mid- and far-infrared fields. In this work, the Se element was introduced to stabilize the Ge-As-Te glass. Some glasses with ΔT ≥ 150 °C have excellent thermal stability, indicating these glasses can be prepared in large sizes for industrialization. The Ge-As-Se-Te (GAST) glasses still have a wide infrared transmission window (3-18 µm) and a high linear refractive index (3.2-3.6), indicating that the GAST glass is an ideal material for infrared optics. Raman spectra show that the main structural units for GAST glass are [GeTe4] tetrahedra, [AsTe3] pyramids, and [GeTe4Se4-x] tetrahedra, and with the decrease of Te content (≤50 mol%), As-As and Ge-Ge homopolar bonds appear in the glass due to the non-stoichiometric ratio. The conductivity σ of the studied GAST glasses decreases with the decrease of the Te content. The highest σ value of 1.55 × 10-5 S/cm is obtained in the glass with a high Te content. The activation energy Ea of the glass increases with the decrease of the Te content, indicating that the glass with a high Te content is more sensitive to temperature. This work provides a foundation for widening the application of GAST glass materials in the field of infrared optics.

Optimizing Evanescent Efficiency of Chalcogenide Tapered Fiber.

Evanescent wave absorption-based mid-infrared chalcogenide fiber sensors have prominent advantages in multicomponent liquid and gas detection. In this work, a new approach of tapered-fiber geometry optimization was proposed, and the evanescent efficiency was also theoretically calculated to evaluate sensing performance. The influence of fiber geometry (waist radius (Rw), taper length (Lt), waist deformation) on the mode distribution, light transmittance (T), evanescent proportion (TO) and evanescent efficiency (τ) is discussed. Remarkably, the calculated results show that the evanescent efficiency can be over 10% via optimizing the waist radius and taper length. Generally, a better sensing performance based on tapered fiber can be achieved if the proportion of the LP11-like mode becomes higher or Rw becomes smaller. Furthermore, the radius of the waist boundary (RL) was introduced to analyze the waist deformation. Mode proportion is almost unchanged as the RL increases, while τ is halved. In addition, the larger the micro taper is, the easier the taper process is. Herein, a longer waist can be obtained, resulting in larger sensing area which increases sensitivity greatly.

High Verdet Constant Glass for Magnetic Field Sensors.

Due to the high transparency, high Verdet constant, as well as easy processing properties, rare-earth ion-doped glasses have demonstrated great potential in magneto-optical (MO) applications. However, the variation in the valence state of rare-earth ions (Tb3+ to Tb4+) resulted in the decreased effective concentration of the paramagnetic ions and thus degraded MO performance. Here, a strategy was proposed to inhibit the oxidation of Tb3+ into Tb4+ as well as improve the thermal stability by tuning the optical basicity of glass networks. Moreover, the depolymerization of the glass network was modulated to accommodate more Tb ions. Thus, a record high effective concentration (14.19 × 1021/cm3) of Tb ions in glass was achieved, generating a high Verdet constant of 113 rad/(T·m) at 650 nm. Lastly, the first application of MO glass for magnetic field sensors was demonstrated, achieving a sensitivity of 0.139 rad/T. We hope our work provides guidance for the fabrication of MO glass with high performance and thermal stability and could push MO glass one step further for magnetic sensing applications.