Effects of a UV absorber in silica-loaded resin on DLP silica fiber preform fabrication.

3D printing technologies have distinguished advantages in manufacturing arbitrary shapes and complex structures that have attracted us to use digital light processing (DLP) technology for specialty silica optical fiber preforms. One of the main tasks is to develop an appropriate recipe for DLP resin that is UV sensitive and loaded with silica nanoparticles. In this work, the effects of a UV absorber in highly silica-loaded resin on DLP printing are experimentally investigated. Spot tests and DLP printing are carried out on resins with varying dosages of a typical UV absorber, Sudan Orange G. Based on the experimental results, the UV absorber can significantly improve the resolution of DLP printed green bodies while requiring a larger exposure dose.

Compact, remote optical waveguide magnetic field sensing using double-pass Faraday rotation-induced optical attenuation.

Compact, magnetic field, B sensing is proposed and demonstrated by combining the two Faraday rotation elements and beam displacement crystals within a micro-optical fiber circulator with a fiber reflector and ferromagnets to allow high contrast attenuation in an optical fiber arm. Low optical noise sensing is measured at λ=1550n m as a change in attenuation, α, of optical light propagating through the rotators and back. The circulator's double-pass configuration, using a gold mirror as a reflector, achieves a magnetic field sensitivity s=Δ α/Δ B=(0.26±0.02)d B/m T with a resolution of Δ B=0.01m T, over a detection range B=0-89m T. The circulator as a platform provides direct connectivity to the Internet, allowing remote sensing to occur. The method described here is amenable to multisensor combinations, including with other sensor technologies, particularly in future integrated waveguide Faraday optical circuits and devices, extending its utility beyond point magnetic field sensing applications.

Scalable Synthesis of Robust MOF for Challenging Ethylene Purification and Propylene Recovery with Record Productivity.

Ethylene (C2H4) purification and propylene (C3H6) recovery are highly relevant in polymer synthesis, yet developing physisorbents for these industrial separation faces the challenges of merging easy scalability, economic feasibility, high moisture stability with great separation efficiency. Herein, we reported a robust and scalable MOF (MAC-4) for simultaneous recovery of C3H6 and C2H4. Through creating nonpolar pores decorated by accessible N/O sites, MAC-4 displays top-tier uptakes and selectivities for C2H6 and C3H6 over C2H4 at ambient conditions. Molecular modelling combined with infrared spectroscopy revealed that C2H6 and C3H6 molecules were trapped in the framework with stronger contacts relative to C2H4. Breakthrough experiments demonstrated exceptional separation performance for binary C2H6/C2H4 and C3H6/C2H4 as well as ternary C3H6/C2H6/C2H4 mixtures, simultaneously affording record productivities of 27.4 and 36.2 L kg-1 for high-purity C2H4 (≥99.9 %) and C3H6 (≥99.5 %). MAC-4 was facilely prepared at deckgram-scale under reflux condition within 3 hours, making it as a smart MOF to address challenging gas separations.

Submonolayer biolasers for ultrasensitive biomarker detection.

Biomarker detection is key to identifying health risks. However, designing sensitive and single-use biosensors for early diagnosis remains a major challenge. Here, we report submonolayer lasers on optical fibers as ultrasensitive and disposable biosensors. Telecom optical fibers serve as distributed optical microcavities with high Q-factor, great repeatability, and ultralow cost, which enables whispering-gallery laser emission to detect biomarkers. It is found that the sensing performance strongly depends on the number of gain molecules. The submonolayer lasers obtained a six-order-of-magnitude improvement in the lower limit of detection (LOD) when compared to saturated monolayer lasers. We further achieve an ultrasensitive immunoassay for a Parkinson's disease biomarker, alpha-synuclein (α-syn), with a lower LOD of 0.32 pM in serum, which is three orders of magnitude lower than the α-syn concentration in the serum of Parkinson's disease patients. Our demonstration of submonolayer biolaser offers great potentials in high-throughput clinical diagnosis with ultimate sensitivity.

Active Sites Decorated Nonpolar Pore-Based MOF for One-step Acquisition of C2 H4 and Recovery of C3 H6.

Herein, a 2-fold interpenetrated metal-organic framework (MOF) Zn-BPZ-TATB with accessible N/O active sites in nonpolar pore surfaces was reported for one-step C2 H4 purification from C2 H6 or C3 H6 mixtures as well as recovery of C3 H6 from C2 H6 /C3 H6 /C2 H4 mixtures. The MOF exhibits the favorable C2 H6 and C3 H6 uptakes (>100 cm3 g-1 at 298 K under 100 kPa) as well as selective adsorption of C2 H6 and C3 H6 over C2 H4 . The C3 H6 - and C2 H6 -selective feature were investigated detailedly by experimental tests as well as sorption kinetic studyies. Molecular modelling revealed the multiple interactions between C3 H6 or C2 H6 molecules and methyl groups as well as triazine rings in pores. Zn-BPZ-TATB not only can directly generate 323.4 L kg-1 and 15.4 L kg-1 of high-purity (≥99.9 %) C2 H4 from C3 H6 /C2 H4 and C2 H6 /C2 H4 mixtures, but also provide a large high-purity (≥99.5 %) C3 H6 recovery capacity of 60.1 L kg-1 from C3 H6 /C2 H4 mixtures. More importantly, the high-purity C3 H6 (≥99.5 %) and C2 H4 (≥99.9 %) with the productivities of 38.2 and 12.7 L kg-1 can be simultaneously obtained from C2 H6 /C3 H6 /C2 H4 mixtures through a single adsorption/desorption cycle.

Voltage, thermal and magnetic field fiber sensors based on magnetic nanoparticles-doped photonic liquid crystal fibers.

In this article, highly sensitive voltage, thermal and magnetic field fiber sensors were obtained in magnetic nanoparticles-doped E7 liquid crystals filled into photonic crystal fibers (PLCF). The voltage and temperature sensitivity reached at 12.598 nm/V and -3.874 nm/°C, respectively. The minimum voltage response time is 48.2 ms. The phase transition temperature Tc of liquid crystal with magnetic dopant was reduced from 60 °C to 46 °C. The magnetic field sensor based on magnetic nanoparticles-doped PLCF were obtained with sensitivity of 118.2 pm/mT from 400 to 460 mT.

One Co-MOF with F Active Sites for Separation of C2H2 from CO2, C2H4, and CH4.

Separating acetylene (C2H2) from other light hydrocarbons and carbon dioxide (CO2) mixtures under mild conditions poses significant challenges due to the remarkably similar properties between C2H2 and those gases. For the goal of C2H2 separation, a F-functionalized organic linker, H2F-PyIP = 2-fluorine-5-(4-pyridyl)isophthalic acid, was designed, and the corresponding metal-organic framework (MOF), {[Co2(F-PyIP)2DMF]·4H2O}n (1), was constructed. The MOF with open channels decorated by the active sites of the F groups revealed the exceptional C2H2 uptake and selectivity over CO2, C2H4, and CH4. The breakthrough experiments with different molar ratios of C2H2-C2H4, C2H2-CO2, and other gas mixtures further verified superior separation capacity of the MOF. In particular, the dynamic separation time intervals for gas mixtures (C2H2/CO2 = 1:1, 1:5, 1:10, and 1:20) fell in the range 30-44 min, highlighting the potential of the MOF for tackling the challenging C2H2/CO2 separation process.

A nickel-based metal-organic framework as a new cathode for chloride ion batteries with superior cycling stability.

Chloride ion batteries (CIBs) have drawn growing attention as attractive candidates for large-scale energy storage technology because of their high theoretical energy densities (2500 W h L-1), dendrite-free characteristics and abundance of chloride-containing materials available worldwide. However, the further development of CIBs is greatly limited by sluggish Cl- diffusion and distinct structural variation of cathode materials, resulting in severe decayed capacity and inferior rate performance. Metal-organic framework (MOF) materials possess regular pores/channels and flexible structural designability to accommodate charge carrier ions, but the application of MOFs in anion-type batteries has not been reported. Here, we demonstrate the first example of Ni(dpip) with two different opening sizes of tubular channels serving as the cathode for high performance CIBs. The Ni-based MOF exhibited a stable reversible capacity of 155 mA h g-1 with an admirable low capacity decay of 0.026% per cycle over 500 cycles and superior kinetics with a 10-10 cm2 s-1 average diffusion coefficient for chloride ions as well. The high performance of the Ni(dpip) cathode results from the synergetic redox couples of Ni metal nodes and N-ligands, the unique double-channel structure for reversible Cl-storage, and the low chloride diffusion energy barrier. This work switches on the new application of MOF-based materials as cathodes for CIBs.

Discriminatory Gate-Opening Effect in a Flexible Metal-Organic Framework for Inverse CO2 /C2 H2 Separation.

Considering the significant application of acetylene (C2 H2 ) in the manufacturing and petrochemical industries, the selective capture of impurity carbon dioxide (CO2 ) is a crucial task and an enduring challenge. Here, a flexible metal-organic framework (Zn-DPNA) accompanied by a conformation change of the Me2 NH2 + ions in the framework is reported. The solvate-free framework provides a stepped adsorption isotherm and large hysteresis for C2 H2 , but type-I adsorption for CO2 . Owing to their uptakes difference before gate-opening pressure, Zn-DPNA demonstrated favorable inverse CO2 /C2 H2 separation. According to molecular simulation, the higher adsorption enthalpy of CO2 (43.1 kJ mol-1 ) is due to strong electrostatic interactions with Me2 NH2 + ions, which lock the hydrogen-bond network and narrow pores. Furthermore, the density contours and electrostatic potential verifies the middle of the cage in the large pore favors C2 H2 and repels CO2 , leading to the expansion of the narrow pore and further diffusion of C2 H2 . These results provide a new strategy that optimizes the desired dynamic behavior for one-step purification of C2 H2 .

Dative B←N bonds based crystalline organic framework with permanent porosity for acetylene storage and separation.

The utilization of dative B←N bonds for the creation of crystalline organic framework (BNOF) has increasingly received intensive interest; however, the shortage of permanent porosity is an obstacle that must be overcome to guarantee their application as porous materials. Here, we report the first microporous crystalline framework, BNOF-1, that is assembled through sole monomers, which can be scalably synthesized by the cheap 4-pyridine boronic acid. The 2D networks of BNOF-1 were stacked in parallel to generate a highly porous supramolecular open framework, which possessed not only the highest BET surface area of 1345 m2 g-1 amongst all of the BNOFs but also features a record-high uptake of C2H2 and CO2 in covalent organic framework (COF) materials to date. Dynamic breakthrough experiments demonstrated that BNOF-1 material can efficiently separate C2H2/CO2 mixtures. In addition, the network can be regenerated in organic solvents with no loss in performance, making its solution processable. We believe that BNOF-1 would greatly diversify the reticular chemistry and open new avenues for the application of BNOFs.

Discrimination of cultivation modes of Dendrobium nobile based on content of mineral elements and ratios of nitrogen stable isotopes / 中国中药杂志

This study explored the feasibility of mineral element content and ratios of nitrogen isotopes to discriminate the cultivation mode of Dendrobium nobile in order to provide theoretical support for the discrimination of the cultivation mode of D. nobile. The content of 11 mineral elements(N, K, Ca, P, Mg, Na, Fe, Cu, Zn, Mn, and B) and nitrogen isotope ratios in D. nobile and its substrate samples in three cultivation methods(greenhouse cultivation, tree-attached cultivation, and stone-attached cultivation) were determined. According to the analysis of variance, principal component analysis, and stepwise discriminant analysis, the samples of different cultivation types were classified. The results showed that the nitrogen isotope ratios and the content of elements except for Zn were significantly different among different cultivation types of D. nobile(P<0.05). The results of correlation analysis showed that the nitrogen isotope ratios, mineral element content, and effective component content in D. nobile were correlated with the nitrogen isotope ratio and mineral element content in the corresponding substrate samples to varying degrees. Principal component analysis can preliminarily classify the samples of D. nobile, but some samples overlapped. Through stepwise discriminant analysis, six indicators, including δ~(15)N, K, Cu, P, Na, and Ca, were screened out, which could be used to establish the discriminant model of D. nobile cultivation methods, and the overall correct discrimination rates after back-substitution test, cross-check, and external validation were all 100%. Therefore, nitrogen isotope ratios and mineral element fingerprints combined with multivariate statistical analysis could effectively discriminate the cultivation types of D. nobile. The results of this study provide a new method for the identification of the cultivation type and production area of D. nobile and an experimental basis for the quality evaluation and quality control of D. nobile.

Quality evaluation and multi-spectral identification of origin herbs of Lonicerae Japonicae Flos based on grey correlation-TOPSIS method / 中国中药杂志

The grey correlation-TOPSIS method was used to evaluate the quality of the origin herbs of Lonicerae Japonicae Flos, and the Fourier transform near-infrared(NIR) and mid-infrared(MIR) spectroscopy was applied to establish the identification model of origin herbs of Lonicerae Japonicae Flos by combining chemometrics and spectral fusion strategies. The content of neochlorogenic acid, chlorogenic acid, cryptochlorogenic acid, caffeic acid, secoxyloganin, isoquercitrin, isochlorogenic acid B, isochlorogenic acid A, and isochlorogenic acid C in six origin herbs of Lonicerae Japonicae Flos was determined by high-performance liquid chromatography(HPLC), and their quality was evaluated by the grey correlation-TOPSIS method. The Fourier transform NIR and MIR spectra of six origin herbs of Lonicerae Japonicae Flos(Lonicera japonica, L. macranthoides, L. hypoglauca, L. fulvotomentosa, L. confuse, and L. similis) were collected. At the same time, principal component analysis(PCA), support vector machine(SVM), and spectral data fusion technology were combined to determine the optimal identification method for the origin herbs of Lonicerae Japonicae Flos. There were differences in the quality of the origin herbs of Lonicerae Japonicae Flos. Specifically, there were significant differences between L. japonica and the other five origin herbs(P<0.01). The quality of L. similis was significantly different from that of L. fulvotomentosa, L. macranthoides, and L. hypoglauca(P=0.008, 0.027, 0.01), and there were also significant differences in the quality of L. hypoglauca and L. confuse(P=0.001). The PCA and SVM 2D models based on a single spectrum could not be used for the effective identification of the origin herbs of Lonicerae Japonicae Flos. The data fusion combined with the SVM model further improved the identification accuracy, and the identification accuracy of the mid-level data fusion reached 100%. Therefore, the grey correlation-TOPSIS method can be used to evaluate the quality of the origin herbs of Lonicerae Japonicae Flos. Based on the infrared spectral data fusion strategy and SVM chemometric model, it can accurately identify the origin herbs of Lonicerae Japonicae Flos, which can provide a new method for the origin identification of medicinal materials of Lonicerae Japonicae Flos.

Boosting Ethane/Ethylene Separation by MOFs through the Amino-Functionalization of Pores.

Adsorption technology based on ethane-selective materials is a promising alternative to energy-intensive cryogenic distillation for separating ethane (C2 H6 ) and ethylene (C2 H4 ). We employed a pore engineering strategy to tune the pore environment of a metal-organic framework (MOF) through organic functional groups and boosted the C2 H6 /C2 H4 separation of the MOF. Introduction of amino (-NH2 ) groups into Tb-MOF-76 not only decreased pore sizes but also facilitated multiple guest-host interactions in confined pores. The NH2 -functionalized Tb-MOF-76(NH2 ) has increased C2 H6 and C2 H4 uptakes and C2 H6 /C2 H4 selectivity. The results of experimental and simulated transient breakthroughs reveal that Tb-MOF-76(NH2 ) has significantly improved one-step separation performance for C2 H6 /C2 H4 mixtures with a high C2 H4 (>99.95 %) productivity of 17.66 L kg-1 compared to 7.53 L kg-1 by Tb-MOF-76, resulting from the suitable pore confinement and accessible -NH2 groups on pore surfaces.

Efficient One-Step Purification of C1 and C2 Hydrocarbons over CO2 in a New CO2-Selective MOF with a Gate-Opening Effect.

Removing CO2 impurity is an essential industrial process in the purification of hydrocarbons. The most promising strategy is the one-step collection of high-purity hydrocarbons by employing CO2-selective adsorbents, which requires improving the CO2 adsorption and separation behavior of adsorbents, especially the low-pressure performance under actual industrial conditions. Herein, we constructed a new flexible metal-organic framework [Zn(odip)0.5(bpe)0.5(CH3OH)]·0.5NMF·H2O (1) (H4odip = 5,5'-oxydiisophthalic acid, bpe = 1,2-bi(4-pyridyl)ethylene, and NMF = N-methylformamide) containing rich ether O adsorption sites in the channels that exhibits remarkable adsorption capacity for CO2 (118.7 cm3 g-1) due to the only gate-opening-type abrupt adsorption of CO2 at room temperature. Its low affinity for other competing gases enables it to deliver high selectivity for the adsorption of CO2 over C1 and C2 hydrocarbons. For equimolar mixtures of CO2-CH4 and CO2-C2H2, the selectivities are 376.0 and 13.2, respectively. Molecular simulations disclose more abundant adsorption sites for CO2 than hydrocarbons in 1. The breakthrough separation performances combined with remarkable stability and recyclability further verify that 1 is a promising adsorbent that can efficiently extract high-purity hydrocarbons through selective capture of CO2.

One-Step C2 H4 Purification from Ternary C2 H6 /C2 H4 /C2 H2 Mixtures by a Robust Metal-Organic Framework with Customized Pore Environment.

One-step C2 H4 purification from ternary C2 H6 /C2 H4 /C2 H2 mixtures by a single adsorbent is of great industrial significance, but few adsorbents achieve this separation. Herein, we report a robust metal-organic framework (MOF) that possesses methyl-decorated nonpolar pores and shows one-step C2 H4 purification (purity >99.9 %) from binary C2 H6 /C2 H4 mixtures and ternary C2 H6 /C2 H4 /C2 H2 mixtures. The methyl groups in pores provide a suitable pore environment to simultaneously enhance the adsorption capacity for C2 H2 and C2 H6 compared to C2 H4 . Simulations revealed the multiple interactions between C2 H6 or C2 H2 molecules and the pore wall, while the interactions with C2 H4 molecules are weak and also unfavorable due to the repulsion from methyl groups in pores. The MOF displays high C2 H6 and C2 H2 uptakes and benchmark C2 H6 /C2 H4 selectivity (2.2), surpassing all of the reported MOFs for one-step C2 H4 purification from ternary C2 H6 /C2 H4 /C2 H2 mixtures.

Optical Fiber-Integrated Metasurfaces: An Emerging Platform for Multiple Optical Applications.

The advent of metasurface technology has revolutionized the field of optics and photonics in recent years due to its capability of engineering optical wavefronts with well-patterned nanostructures at subwavelength scale. Meanwhile, inspired and benefited from the tremendous success of the "lab-on-fiber" concept, the integration of metasurface with optical fibers has drawn particular interest in the last decade, which establishes a novel technological platform towards the development of "all-in-fiber" metasurface-based devices. Thereby, this review aims to present and summarize the optical fiber-integrated metasurfaces with the current state of the art. The application scenarios of the optical fiber metasurface-based devices are well classified and discussed accordingly, with a brief explanation of physical fundamentals and design methods. The key fabrication methods corresponding to various optical fiber metasurfaces are summarized and compared. Furthermore, the challenges and potential future research directions of optical fiber metasurfaces are addressed to further leverage the flexibility and versatility of meta-fiber-based devices. It is believed that the optical fiber metasurfaces, as a novel all-around technological platform, will be exploited for a large range of applications in telecommunication, sensing, imaging, and biomedicine.

Compact terahertz birefringent gratings for dispersion compensation.

Terahertz radiation as an upcoming carrier frequency for next-generation wireless communication systems has great potential to enable ultra-high-capacity transmissions with several tens of gigahertz bandwidths. Nevertheless, dispersion is one of the main impairments in achieving a higher bit rate. Here, we experimentally demonstrate a compact terahertz dispersion compensator based on subwavelength gratings. The gratings are fabricated from the low-loss cyclic olefin copolymer exploiting micro-machining fabrication techniques. With the strong index modulation introduced in the subwavelength grating, the high negative group velocity dispersion of -188 (-88) ps/mm/THz is achieved at 0.15 THz for x-polarization (y-polarization), i.e., 7.5 times increase compared to the state-of-the-art reported to date for terahertz. Such high negative dispersion is realized in a grating of 43 mm length. The asymmetric cross-section and periodic-structural modulation along propagation direction lead to considerable birefringence that maintains and filters two orthogonal polarization states, respectively. These polymer-based birefringent gratings can be integrated into terahertz communication systems for dispersion compensation of both long-haul wireless links and waveguide-based interconnect links.

Compact Tri-FFPI sensor for measurement of ultrahigh temperature, vibration acceleration, and strain.

As a high-precision fiber optic sensor, a single optical fiber Fabry Pérot interferometer (FFPI) sensor is often used to measure parameters such as temperature or strain. However, the use of combined FFPIs to measure multiple parameters simultaneously has rarely been reported. In this paper, a compact Tri-FFPI sensor consisting of three series-connected FFPIs is proposed to measure high temperature, high acceleration, and large strain. The total length and diameter of the sensing part are only 2558.9 µm and 250 µm, respectively. One of the FFPIs, FFPI-1, contains a cantilever beam structure to measure vibration acceleration. FFPI-2 is used to measure temperature and the temperature compensation of the strain measurement. FFPI-3 is used to measure strain. To ensure that the sensor has high measurement sensitivity, two demodulation methods are used: the light intensity demodulation method for vibration acceleration and the wavelength demodulation method for temperature and strain. The sensor is capable of withstanding ultrahigh temperatures up to 1000°C.

Determination of arsenic in urine by hydride generation atomic fluorescence spectrometry with ammonium persulfate digestion / 中华地方病学杂志

Objective:To establish a hydride generation atomic fluorescence method using ammonium persulfate as the digestion reagent for determination of arsenic in urine (hereinafter referred to as this method).Methods:The collected urine samples with ammonium persulfate were heated and digested on the tubular electric heating automatic control constant temperature digester (60 holes), with 5% hydrochloric acid solution as reaction medium and current carrier and 1.5% potassium borohydride solution as reducing agent. Arsenic content was determined with a four-channel atomic fluorescence spectrometer. The arsenic standard solution of 0 - 10 μg/L was prepared to determine the standard curve of this method, and the method was evaluated from the detection limit, linear range, correlation coefficient, precision, standard addition recovery experiment, and urine arsenic quality control sample detection. The standard method "Determination of Arsenic in Urine by Hydride Generation Atomic Fluorescence Spectrometry" (WS/T 474-2015, referred to as the standard method) was used for comparison experiments.Results:When the sampling volume was 1 ml, the detection limit of this method (digest with 1 ml 1.5 mol/L ammonium persulfate) was 0.03 μg/L. In the range of arsenic content from 0 - 10 μg/L, the linear relationship between arsenic content and fluorescence intensity was good, and the correlation coefficients ( r) were all 0.999 9. The relative standard deviations( RSD) of the three replicates of urine samples with different concentrations were 1.00%, 0.89% and 0.49%, respectively. Urine arsenic quality control samples were tested, and the test results were all within the range of public values; the overall average recovery was 102.29%, and the recovery range was 92.10% - 108.15%. Compared with the standard method in the determination results of 20 urine samples, the difference was not statistically significant ( t = - 0.40, P > 0.05). Conclusions:The hydride generation atomic fluorescence spectrometry using ammonium persulfate as digestion reagent for the determination of arsenic in urine has the advantages of low detection limit, good precision, high accuracy, small amount of sampling and digestion reagent, simple operation, and less harmful gas generation in sample pretreatment. It is suitable for rapid determination of arsenic in urine in large quantities.

Research Progress of Mesenchymal Stem Cells and Their Exosomes on Tumors / 中国肺癌杂志

In China, malignant tumor is the main cause of death in both urban and rural areas. Mesenchymal stem cells (MSCs) have multidirectional differentiation potential, self-renewal ability and good immunomodulatory properties. Exosomes, as important paracrine substances of MSCs, mediate information exchange and transmission between cells in tumor microenvironment and influence the occurrence and development of tumors. Recently, conflicting findings have been reported on the effects of MSCs and their exosomes on tumors. On the one hand, MSCs and their exosomes are tumorigenic and can target specific sites to inhibit tumor growth; On the other hand, there is also evidence that MSCs could affect tumor growth and migration as part of the tumor microenvironment. In this paper, we will review the relationship between MSCs and exosomes and tumorgenesis and development, as well as how MSCs and exosomes play different roles in tumorgenesis and development, in order to provide beneficial help for tumor diagnosis, prognosis and precise treatment.
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