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Surface-enhanced Raman scattering (SERS) is a powerful tool for trace substance detection and analysis. However, traditional SERS detection based on substrates usually separates sampling and detection, which are time consuming and lack portability for practical applications. In this study, we developed a SERS fiber optic probe using a simple and efficient laser-induced evaporation assembly method. By direct immersion of the fiber in a microliter colloidal solution of silver nanocubes (Ag NCs) under laser induction, a monolayer of uniform and dense Ag NCs was modified on the end face of the optical fiber. The fabricated SERS fiber optic probe demonstrated excellent reproducibility and stability with a detection limit of less than 10–8 M for the 4-mercaptobenzoic acid (4-MBA), with the intensity of its two characteristic Raman peaks showing a high linear correlation with the logarithm of the concentration. Furthermore, by combining Ag NCs with bromide ions, the Ag-Br NCs fiber optic probe we fabricated and exhibited outstanding performance in detecting organic pollutants polycyclic aromatic hydrocarbons (PAHs). This work may have potential significance in broadening the application field of SERS fiber-optic probes.

A novel π-phase-shifted (PS) long-period fiber-grating (LPFG) sensor operating near the phase-matching turning point (PMTP) was proposed. The PS-LPFG sensor can simultaneously detect temperature, strain, refractive index (RI), and pH. Due to the introduction of π phase shift, the double resonance peak of the selected cladding mode was divided into four loss peaks, which is convenient for multiparameter measurement. By monitoring the resonant-wavelength shifts of four dips of PS-LPFG, simultaneous detection of temperature, strain, RI, and pH can be achieved. Moreover, using a simple LPFG design on one fiber and a multiparameter matrix algorithm, the crosstalk between multiple signals was eliminated. Graphene oxide/polyvinyl alcohol (GO/PVA) hydrogel was coated onto the grating sensing area to measure the change in pH, and the sensitivity was higher than that of the same type of fiber-grating sensor. Results showed that the maximum sensitivity of temperature, strain, RI, and pH of the fabricated phase-shifted grating sensing structure were 0.2128 nm/°C, 0.1225 nm/μϵ, 718 nm/RIU, and -1.0166 nm/pH, respectively. Overall, the proposed sensor had great potential applications in monitoring marine environments and biochemistry sensing.

Surface-enhanced Raman scattering (SERS) has great potential in the field of rapid detection of pesticide residues in food. In this paper, a fiber optic SERS sensor excited by evanescent waves was proposed for efficient detection of thiram. Silver nanocubes (Ag NCs) were prepared as SERS active substrates, which had much stronger electromagnetic field intensity than nanospheres under laser excitation due to much more “hot spots”. By using the method of electrostatic adsorption and laser induction, Ag NCs were uniformly assembled at the fiber taper waist (FTW) for enhancing the Raman signal. Different from the traditional way of stimulation, evanescent wave excitation greatly increased the interaction area between the excitation and analyte, while reducing the damage of the excited light to the metal nanostructures. The methods proposed in this work have been successfully used to detect the pesticide residues of thiram and showed good detection performance. The detection limits for 4-Mercaptobenzoic acid (4-MBA) and thiram were determined to be 10–9and 10–8M, the corresponding enhancement factor could be 1.64 × 105and 6.38 × 104. Low concentration of thiram was detected in the peels of tomatoes and cucumbers, indicating its feasibility in actual sample detection. The combination of evanescent waves and SERS provides a new direction for the application of SERS sensors, which had great application potential in the field of pesticide residue detection.

Chalcogenide solid-state electrolytes (SEs) have been regarded as promising candidates for lithium dendrite suppression due to their high ionic conductivity, suitable mechanical strength, and large Li+ion transference number. However, the wide applications of SEs in pragmatic all-solid-state batteries are still retarded by their limited interface stability, which leads to lithium dendrite growth and formation of interphase with high resistance. In addition, the interphase evolution mechanism between SEs and metallic Li anodes remains unclear. Herein, this work demonstrates that the interfacial stability of Li2S–SiS2–P2S5SEs can be effectively enhanced by tuning the interphase through LiI incorporation. This strategy contributes to a high ionic conductivity of the SEs and electronic insulation interphase containing LiI. Thus, the 70(60Li2S–28SiS2–12P2S5)–30 LiI SEs prepared by melt-quenching exhibit a high ionic conductivity of 1.74 mS cm–1at room temperature and a larger critical current density of 1.65 mA cm–2at 65 °C. The cycling life of the symmetric Li|SEs|Li cell is up to 200 h without significant resistance growth at 0.1 mA cm–2at room temperature. This enhanced interface stability is revealed to originate from the in situ-formed LiI within the interphase, which prevents continual SEs degradation and suppresses lithium dendrite growth. This work provides a vital understanding of interphase evolution, which is valuable for designing SEs with long cycling stability.

In this study, a one-step hydrothermal preparation strategy was employed to synthesize a graphitic carbon nitride (g-C3N4) composite photocatalyst co-decorated with Fe sites and carbon quantum dots (Fe–CQDs/g-C3N4). Through a series of characterisation techniques, the successful integration of Fe atoms and carbon quantum dots (CQDs) onto g-C3N4was achieved. Moreover, the presence of Fe, specifically Fe–N bonds, enhanced the charge-carrier transfer. With carbamazepine (CBZ) as the model pollutant, Fe–CQDs/g-C3N4increased the photocatalytic activity with efficient peroxymonosulfate (PMS) activation under solar light irradiation, achieving 100 % CBZ degradation in 15 min over a wide pH range (3–9). Doping of the catalyst with Fe and CQDs resulted in a narrowing of the catalyst bandgap (2.25 eV) compared to that of g-C3N4(2.79 eV), confirming the promotion of photo-induced charge separation. The CBZ degradation pathways were elucidated by ultrahigh-performance liquid chromatography and high-definition mass spectrometry. The Fe–CQDs/g-C3N4composite was found to possess substantial potential for the efficient degradation of pollutants.

The local coordination structure of metal atoms in single-atom catalysts (SACs) greatly influences their catalytic performance. And for most SACs, single metal atoms were anchored on carbon materials with N or C coordination. However, the rational design of oxygen-containing SACs and analyzing its structure–performance relationship remain challenging. Herein, we used amino-rich compounds to tailor the metatungstate and fix the W atoms and finally obtained the oxygen-containing W-SACs. The structural evolution of tungsten and its coordination atoms were tracked by electrospray ionization high-definition mass spectrometry. Furthermore, aberration-corrected transmission electron microscopy, X-ray absorption fine-structure spectroscopy, and first-principles calculation results revealed that different from the traditional SACs, the WO2N2moiety (W coordinated with two O atoms and two N atoms) may be the favored structure for W species. This special structure promoted the energy transfer for enhancing singlet oxygen generation. This work presents an efficient way to prepare more high-efficiency SACs by atomic-scale tailoring and structural evolution tracking at the molecular level.

CMGNPs can promote M1 polarization of macrophages and TLR4 is involved in CMGNP-induced inflammation.

Using conventional differential scanning calorimetry (DSC) and Flash DSC, we revisited the old question of crystallization kinetics of chalcogens. Together with the appropriate viscosity models and Stokes–Einstein relation, the quantitative results of crystallization kinetics in chalcogenide supercooled liquids were revealed. It showed that the fragilities of S, Se, Te are 126, 67.5, 60, and the maximum crystal growth rates are 9.7 × 10–3, 1.3 × 10–6, and 0.47 m s–1at 0.91, 0.94, and 0.86 Tm, respectively. Such results not only benefit to understand the fundamental science but also help to design new chalcogenide compositions for applications.

Cytotoxic T lymphocyte (CTL) epitope peptide-based vaccines are widely used in cancer and infectious disease therapy. We previously generated an immune-tolerant elastin-like polypeptides (iTEPs)-based carrier to deliver a peptide CTL vaccine and enhance the efficiency of the vaccine. To further optimize the vaccine carrier, we intended to potentiate its function by designing an iTEP-based carrier that was able to deliver adjuvant and a vaccine epitope as one molecule. Thus, we fused a 9-mer H100, a peptide derived from the high-mobility group box 1 protein (HMGB1) that could induce activation of dendritic cells (DCs), with an iTEP polymer to generate a new iTEP polymer named H100-iTEP. The H100-iTEP still kept the feature of reversible phase transition of iTEPs and should be able to be used as a polymer carrier to deliver peptide vaccines. The expression levels of CD80/CD86 on DCs were assessed using flow cytometry. The iTEP fusion-stimulated IL-6 secretion by DCs was measured with ELISA. Activation of antigen-specific CD8+T cells induced by iTEP fusions was examined through a B3Z hybridoma cell activation assay. In vivo CTL activation promoted by iTEP fusions was detected by an IFN-γ-based ELISPOT assay. The iTEP fused with H100could induce maturation of DCs in vitro as evidenced by increased CD80 and CD86 expression. The iTEP fusion also promoted activation of DCs by increasing secretion of a proinflammatory cytokine IL-6. The N-terminus or C-terminus fusion of H100to iTEP had a similar effect and a reduced form of cysteine in iTEP fusions was required for DC stimulation. iTEP fusions potentiated a co-administrated CTL vaccine by increasing an antigen-specific CTL response in vitro and in vivo. When the H100-iTEP was fused to a CTL epitope to generate a one-molecule vaccine, this self-adjuvanted vaccine elicited a stronger antigen-specific CTL response than a vaccine adjuvanted by Incomplete Freund's Adjuvant. Thus, we have successfully generated a functional, one-molecule iTEP-based self-adjuvanted vaccine.

A simple and seamless broadband optical frequency comb (OFC) generator is proposed and experimentally demonstrated using a Fabry–Perot quantum dot mode-locked laser combined with a dual-driven LiNbO_3 Mach–Zehnder modulator driven by a low-power radio frequency (RF) signal. It is experimentally demonstrated that the 10-dB seamless bandwidth of the OFC is 8.2 nm (1.02 THz), which has 62 and 40 comb lines for frequency intervals of 16.56 GHz and 24.84 GHz, respectively. The single-sideband phase noise is as low as −112 and −108  dBc/Hz at an offset of 10 kHz, respectively, for the photodetector-converted 16.56 and 24.84 GHz frequency carriers. Correspondingly, the RF linewidths of the 16.56 GHz and 24.84 GHz carriers are about 251 Hz–263 Hz, respectively. Using a QD laser, an ultra-low phase noise and quasi-tunable broadband OFC generator is obtained easily.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus driving the ongoing coronavirus disease 2019 (COVID-19) pandemic, continues to rapidly evolve. Because of the limited efficacy of vaccination in prevention of SARS-CoV-2 transmission and continuous emergence of variants of concern (VOCs), orally bioavailable and broadly efficacious antiviral drugs are urgently needed. Previously, we showed that the parent nucleoside of remdesivir, GS-441524, has potent anti–SARS-CoV-2 activity. Here, we report that esterification of the 5′-hydroxyl moieties of GS-441524 markedly improved antiviral potency. This 5′-hydroxyl-isobutyryl prodrug, ATV006, demonstrated excellent oral bioavailability in rats and cynomolgus monkeys and exhibited potent antiviral efficacy against different SARS-CoV-2 VOCs in vitro and in three mouse models. Oral administration of ATV006 reduced viral loads and alleviated lung damage when administered prophylactically and therapeutically to K18-hACE2 mice challenged with the Delta variant of SARS-CoV-2. These data indicate that ATV006 represents a promising oral antiviral drug candidate for SARS-CoV-2.

(ZnO)x(Sb2Te3)1–xmaterials with different ZnO contents have been systemically studied with an aim of finding the most suitable composition for phase change memory applications. It was found that ZnO-doping could improve thermal stability and electrical behavior of Sb2Te3film. Sb2Te3-rich nanocrystals, surrounded by ZnO-rich amorphous phases, were observed in annealed ZnO-doped Sb2Te3composite films, and the segregated domains exhibited a relatively uniform distribution. The ZnO-doped Sb2Te3composite films, especially with 5.2 at% ZnO concentration were found to have higher crystallization temperature, higher crystalline resistance, and faster crystallization speed in comparison with Ge2Sb2Te5. A reversible repetitive optical switching behavior can be observed in (ZnO)5.2(Sb2Te3)94.8, confirming that the ZnO doping is responsible for a fast switching and the compound is stable with cycling. Therefore, it is promising for the applications in phase change memory devices.

Structural order beyond the next-nearest-neighbor structural units is of great interest in network glasses, especially in chalcogenide glasses, but little specific description can be reached. Here, the structure of pseudobinary (100 – x)GeS2–xSb2S3chalcogenide glasses is elucidated using differential scanning calorimetry, Raman scattering, and laser-induced phase transformation experiments over its full range (0 ≤ x≤ 100) of compositions. We observe two compositional thresholds of x= 40 and 50 in the calorimetric experiments, which are confirmed by Raman scattering and laser-induced phase transformation studies, respectively. Three structural features can be derived from these results: the structural motifs in this glass network are the [SbS3] pyramid and [GeS4] tetrahedra, respectively; at x≥ 40, the connection between [GeS4] tetrahedra vanishes; and at x≥ 50, the aggregation of four [SbS3] units happens, preparing for the laser-induced crystallization of Sb2S3crystallites. Combined with valuable indication from the topological thresholds, a specific structural model covering the arrangement of structural units in a large atomic scale is clarified, which can perfectly explain all the experimental results. This work provides a new way to get insight into the intermediate-range order of glass networks and understand their related physical properties.

Surface plasmon resonance (SPR) of noble metal nanoparticles (NPs) fostered a new area of nanophotonics, especially in the selective photon absorption and scattering. The precipitation of Ag NPs in glass would enhance the emission efficiency. Here, we studied the effects of annealing temperature (resulted in the increased Ag NPs’ concentration) or AgCl concentration on the luminescence properties of Er3+/Yb3+codoped bismuth-germanate glasses which were synthesized by a single-step melting–quenching technique. The SPR peak of Ag NPs appears around 600 nm, and the size of precipitated Ag NPs (spherical, hexagonal) ranges from 5 to 15 nm. With the precipitation of the Ag NPs, more intense green (527 nm, 548 nm) and red (661 nm) upconversion (UC) emission bands are observed up to 7.7, 10.1, and 6.5 folds in the glass containing 1 wt % AgCl annealed at 480 °C for 24 h, respectively. The Ag NPs embedded glasses showed significantly local field change that allowed for more bright UC emission by SPR.

In the present study, a simple approach has been presented to in situ deposition of Pd-doped well-crystallized SnO2nanocrystals on the surface of multiwalled carbon nanotubes (MWCNTs) in the ethanol solution of SnCl2. The morphology, microstructure and surface chemistry of the as-prepared nanocomposites were characterized by high resolution transmission electron microscope (HRTEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), respectively. The HRTEM and XRD results show that the well-crystallized SnO2nanocrystals with uniform crystal size (about 5 nm) tightly and homogenously coat on the entire surface of the MWCNTs. The carboxylic function groups on the MWCNTs surface may supply nucleation sites for facilitating the in situ deposition of SnO2nanocrystals. The XPS results reveal that the chemical states of the nanocomposites and the dopant of Pd mainly exists in two chemical states as Pd2+and Pd4+. The response of the 2.5 at% Pd-doped SnO2/MWCNTs nanocomposites to 1000 ppm NO at the temperature of 250 °C behaviors better, whose response time is about 70 s and the sensitivity is about 4.62.

A series of silver (Ag^0) nanoclusters embedded in bismuthate glasses (Bi_2O_3-B_2O_3-TiO_2) were synthesized by the thermochemical reduction method. When B_2O_3 was substituted with TiO_2, the refractive index of the encapsulating medium increased, leading to redshifting of the surface plasmon resonance (SPR) absorption band of Ag^0, which was initially located at 612 nm. Z-scan measurements with femtosecond laser pulses at 800 nm showed that third-order optical nonlinearities (TONs) were significantly enhanced in the SPR redshifted samples, and calculation of the figure of merit manifested excellent performances of present Ag^0-bismuthate nanocomposites for TON-based all-optical switching.

We present the measurement of the third-order nonlinearity of Bi_2O_3-B_2O_3-BaO glasses using the single Z-scan method with femtosecond laser pulses at 750-850 nm. Both third-order nonlinear refraction γ and two photon absorption coefficient β are investigated. The γ shows an increasing tendency with increasing BaO content, and the largest value is estimated to be 7.2×10^-14 cm^2/W, which is as large as those of chalcogenide glasses. The dependence of β on the normalized photon energy is studied.

Ce^3+ and B_2O_3 are introduced into erbium-doped Bi_2O_3-SiO_2 glass to enhance the luminescence emission and optic spectra characters of Er^3+. The energy transfer from Er^3+ to Ce^3+ will obviously be improved with the phonon energy increasing by the addition of B_2O_3. Here, the nonradiative rate, the lifetime of the ^4I_11/2?^4I_13/2 transition, and the emission intensity and bandwidth of the 1.5 μm luminescence with the ^4I_13/2?^4I_15/2 transition of Er^3+ are discussed in detail. The results show that the optical parameters of Er^3+ in this bismuth-borate-silicate glass are nearly as good as that in tellurite glass, and the physical properties are similar to those in silicate glass. With the Judd-Ofelt and nonradiative theory analyses, the multiphonon decay and phonon-assisted energy-transfer (PAT) rates are calculated for the Er^3+/Ce^3+ codoped glasses. For the PAT process, an optimum value of the glass phonon energy is obtained after B_2O_3 is introduced into the Er^3+/Ce^3+ codoped bismuth-silicate glasses, and it much improves the energy-transfer rate between Er^3+^4I_11/2?^4I_13/2 and Ce^3+^2F_5/2?^2F_7/2, although there is an energy mismatch.

Summary: An efficient in vitro plant regeneration system from cotyledons was established in tetraploid Isatis indigotica Fort. Factors influencing shoot regeneration from cotyledons, including culture medium type, combinations of plant growth regulators, and sucrose concentrations in the medium, as well as illumination were investigated. Murashige and Skoog's (MS) medium was found to be best for promoting shoot regeneration, followed by Gamborg's B5 and White's medium. The highest shoot regeneration frequency was achieved from cotyledons cultured on MS medium supplemented with 2.0 mgl−1 (8.9 μM) 6-benzyladenine and 1.0 mgl−1 (5.4 μM) α-naphthaleneacetic acid (NAA), with 97.9% regeneration, associated with a high number of multiple shoots developed per explant (8.6 shoots per explant). A sucrose concentration of 3% present in the medium and light conditions were beneficial for shoot regeneration. The shoots developed were rooted in a half-strength MS medium supplemented with 1.0 mgl−1 (5.4 μM) NAA and successfully transplanted in soil in pots with over 85% survival. The establishment of an efficient plant regeneration procedure from cotyledons provides a basis for the rapid in vitro multiplication of tetraploid Isatis indigotica Fort., one of the most extensively used medicinal plants in China currently under great shortage.

Preventing cancer metastasis is one of the remaining challenges in cancer therapy. As an efficient natural product, alpha‐tocopheryl succinate (α‐TOS), the most effective form of vitamin E, holds great anticancer potential. To improve its efficacy and bioavailability, lipid‐coated calcium carbonate/phosphate (LCCP) nanoparticles (NPs) with folic acid and PEG modification are synthesized for efficient delivery of α‐TOS to 4T1 cancer cells. The optimized LCCP‐FA NPs (NP‐TOS15) show an α‐TOS loading efficiency of around 60%, and enhanced uptake by 4T1 metastatic cancer cells. Consequently, NP‐TOS15 significantly enhance the anticancer effect in combination with interferon‐gamma (IFN‐γ) in terms of apoptosis facilitation and migration inhibition. Importantly, NP‐TOS15 upregulate the anticancer immunity via downregulating program death ligand 1 (PD‐L1) expression that is initially induced by IFN‐γ, and remarkably prevent the lung metastasis, particularly in combination with IFN‐γ. Further investigation reveals that this combination therapy also modulates the cytotoxic lymphocyte infiltration into the tumor microenvironment for tumor elimination. Taken together, the NP delivery of α‐TOS in combination with IFN‐γ provides an applicable strategy for cancer therapy. Lipid‐coated calcium carbonate/phosphate nanoparticles are fabricated for vitamin E derivative delivery to tumor cells in vitro and tumor tissues in vivo. With interferon‐γ, the combination treatment efficiently inhibits 4T1 tumor growth and prevents lung metastasis, which is probably related to downregulation of interferon‐γ induced PD‐L1 expression by nanoparticle‐delivered vitamin E.

P_(2)O_(5).BaO.Na_(2)O.K_(2)O glasses doped with various content of Eu_(2)O_(3) were prepared using high temperature melting method, and the Eu^(2+) ions in the phosphate glasses were obtained with the aid of the reductive action of silicon powder. The fabricating conditions, fluorescence, excitation spectra of the glasses were then studied. The glasses containing europium show a broad emission band at 450 nm and sharp bands from 580 to 650 nm, and the co-existence of Eu^(2+) and Eu^(3+) is identified. Also, a good glass with a dominant proportion and large quantity of Eu^(2+) ions can be obtained by the reductive action of silicon powder and proper processing.

Glass transitions of Te-based phase-change materials (PCMs) were studied by modulated differential scanning calorimetry. It was found that both Ge2Sb2Te5and GeTe are marginal glass formers with ?T(= Tx? Tg) less than 2.1 °C when the heating rate is below 3 °C min?1. The fragilities of Ge2Sb2Te5and GeTe can be estimated as 46.0 and 39.7, respectively, around the glass transition temperature, implying that a fragile-to-strong transition would be presented in such Te-based PCMs. The above results provide direct experimental evidence to support the investigation of crystallization kinetics in supercooled liquid PCMs.

We explored the structural and physical properties of Sb-rich Zn-Sb-Te films in order to combine the good thermal stability of ZnSb with the high crystallization speed of Sb2Te. The films generally exhibit two different crystallization characteristics described as follows: amorphous ? Sb2Te crystalline phase if the Zn content in the film is less than ?10 at. % and amorphous ? Sb crystalline phase if the Zn content is more than ?10 at. %. Among the films, the Zn28.62Sb53.69Te17.69film was found to show the highest crystallization temperature (?255 °C), best 10 year data retention (?165.9 °C), and shortest crystallization time of ?58 ns at 70 mW with a stable rhombohedral Sb phase; thus, it is considered promising for phase-change memory applications.

Compared with an undoped Sb3Te film, a Zn26.28(Sb3Te)73.72film exhibits high crystallization temperature (?202 °C) and activation energy of crystallization (?3.28 eV), resulting in stability at high temperatures with an extrapolated life-time of 10 years at 130 °C. The crystalline resistance increases and the amorphous/crystalline resistance ratio is about 104, which is helpful to achieve a high On/OFF ratio. The optical band gap of a Zn26.28(Sb3Te)73.72film decreases as it transforms from the amorphous phase to the crystalline phase. The average kinetic exponent (n) of the film is 2.44, indicating that its crystallization mechanism is of the nucleation-dominated type.

A high channel-count comb filter based on multi-concatenated sampled chirped fiber Bragg gratings (MC-SCFBGs) is proposed and optimally designed by using several chirped gratings with different fundamental grating periods, instead of non-grating sections of SCFBGs. The numerical simulations of the reflection spectra show that the channel spacing and the channel bandwidth in MC-SCFBGs are smaller than those in multi-concatenated chirped fiber Bragg gratings (MC-CFBGs) and that the spectral bandwidth of MC-SCFBGs can be greatly broadened by increasing the cascade number of the grating sections in each sampling period.

This paper investigates theoretically the suppression of relaxation oscillation (RO) in strong optical injection-locked semiconductor laser diode (SLD). The theoretical model is based on external injection locking (IL) in a SLD. In our simulation, an adaptive fourth-order Runge-Kutta algorithm is used to solve the rate equations of injection-locked SLD, the temporal evolution of the carrier and the light intensity in the SLD are obtained. Compared with previous reports of weak optical IL, where IL in SLD will experience a RO and finally come to a steady state, it is found in our study that this RO can be suppressed very well when employing strong optical IL, and the settling time in SLD becomes shorter with high intensity of injection; we also find that the suppression level is almost the same with the same injection ratio while different injection detune. And we believe our results of IL in the SLD with dc excitation can contribute to increase the modulation bandwidth of SLD.