HSCs-derived exosomes regulate the levels of inflammatory cytokines in HIBECs through miR-122-5p mediated p38 MAPK signaling pathway.

PBC is an autoimmune-mediated liver disease, and intrahepatic biliary epithelial cells (IBECs) are the target cells of early damage. Previous studies found that miRNAs and inflammation is closely related to PBC. In this study, we extracted exosomes from serum and human IBECs supernatant, and RNA-sequence analyzed the expression profiles of miRNAs. Elisa measured the levels of inflammatory cytokines. RT- qPCR and western blot detected the levels of miR-122-5p, p38 and p-p38. The results showed that 263 differentially expressed (DE) miRNAs were identified in serum exosomes of PBC patients. The levels of IL-1ß, IL-6, IL-12, IL-17 A, IFN-γ, TNF-α and TGF-ß1 in peripheral blood of PBC patients were higher than those of normal controls. According to the validation results and previous literature, exosomal miR-122-5p was finally selected as the study object, and correlated with inflammatory factors. In vitro experiments further found that exosomal miR-122-5p may derive from hepatic stellate cells (HSCs), and can be HIBECs intake, and influence HIBECs inflammatory factor levels though p38 MAPK signaling pathways. This may provide a new strategy for the treatment of PBC.

Lewis-Acid-Catalyzed (3+2) Annulation of 2-Indolylmethanols with Propargylic Alcohols to Access Cyclopenta[b]indoles.

Herein, a Sc(OTf)3-catalyzed (3+2) annulation of 2-indolylmethanols with propargylic alcohols is reported. The reaction proceeds via a Friedel-Crafts-type allenylation/5-exo-annulation cascade. In the reaction, 2-indolylmethanol is used as a three-carbon synthon, and propargyl alcohol is used as a two-carbon synthon. This method provides a direct and high-yield pathway for synthetically useful cyclopenta[b]indoles. In general, the method features easily accessible substrates with broad scope and generality, the formation of multiple bonds with high efficiency, and easy scale-up.

A compound Kinoform/Fresnel zone plate lens with 15 nm resolution and high efficiency in soft x-ray.

X-ray microscope as an important nanoprobing tool plays a prevailing role in nano-inspections of materials. Despite the fast advances of high resolution focusing/imaging reported, the efficiency of existing high-resolution zone plates is mostly around 5% in soft x-ray and rapidly goes down to 1%-2% when the resolution approaches 10 nm. It is well known that the rectangular zone shape, beamstop, limited height/width ratios, material absorption of light and structural defects are likely responsible for the limited efficiency. Although zone plates with Kinoform profile are supposed to be efficient, progress for achieving both high resolution (<30 nm) and high efficiency (>5%) have hardly been addressed in soft x-ray. In this work, we propose a compound Kinoform/Fresnel zone plate (CKZP) by combing a dielectric Kinoform zone plate with a 15 nm resolution zone plate. Greyscale electron beam lithography was applied to form the 3D Kinoform zone plate and atomic layer deposition was carried out to form the binary zone plate. Optical characterizations demonstrated 15 nm resolution focusing/imaging with over 7.8% efficiency in soft x-ray. The origin of the efficiency improvement behind the proposed compound lens is theoretically analyzed and discussed.

Initial probe function construction in ptychography based on zone-plate optics.

X-ray ptychography is a popular variant of coherent diffraction imaging that offers ultrahigh resolution for extended samples. In x-ray ptychography instruments, the Fresnel zone-plate (FZP) is the most commonly used optical probe system for both soft x-ray and hard x-ray. In FZP-based ptychography with a highly curved defocus probe wavefront, the reconstructed image quality can be significantly impacted by the initial probe function form, necessitating the construction of a suitable initial probe for successful reconstruction. To investigate the effects of initial probe forms on FZP-based ptychography reconstruction, we constructed four single-mode initial probe models (IPMs) and three multi-mode IPMs in this study, and systematically compared their corresponding simulated and experimental reconstructions. The results show that the Fresnel IPM, spherical IPM, and Fresnel-based multi-mode IPMs can result in successful reconstructions for both near-focus and defocus cases, while random IPMs and constant IPMs work only for near-focus cases. Consequently, for FZP-based ptychography, the elaborately constructed IPMs that closely resemble real probes in wavefront phase form are more advantageous than natural IPMs such as the random or constant model. Furthermore, these IPMs with high phase similarity to the high-curvature large-sized probe adopted in experiments can help greatly improve ptychography experiment efficiency and decrease radiation damage to samples.

In Situ X-ray Absorption Spectroscopy of Metal/Nitrogen-doped Carbons in Oxygen Electrocatalysis.

Metal/nitrogen-doped carbons (M-N-C) are promising candidates as oxygen electrocatalysts due to their low cost, tunable catalytic activity and selectivity, and well-dispersed morphologies. To improve the electrocatalytic performance of such systems, it is critical to gain a detailed understanding of their structure and properties through advanced characterization. In situ X-ray absorption spectroscopy (XAS) serves as a powerful tool to probe both the active sites and structural evolution of catalytic materials under reaction conditions. In this review, we firstly provide an overview of the fundamental concepts of XAS and then comprehensively review the setup and application of in situ XAS, introducing electrochemical XAS cells, experimental methods, as well as primary functions on catalytic applications. The active sites and the structural evolution of M-N-C catalysts caused by the interplay with electric fields, electrolytes and reactants/intermediates during the oxygen evolution reaction and the oxygen reduction reaction are subsequently discussed in detail. Finally, major challenges and future opportunities in this exciting field are highlighted.

Thermal drift correction method for laboratory nanocomputed tomography based on global mixed evaluation.

Nanocomputed tomography (nanoCT) is an effective tool for the nondestructive observation of 3D structures of nanomaterials; however, it requires additional correction phantom to reduce artifacts induced by the focal drift of the X-ray source and mechanical thermal expansion. Drift correction without a correction phantom typically uses rapidly acquired sparse projections to align the original projections. The noise and brightness difference in the projections limit the accuracy of existing feature-based methods such as locality preserving matching (LPM) and random sample consensus (RANSAC). Herein, a rough-to-refined correction framework based on global mixed evaluation (GME) is proposed for precise drift estimation. First, a new evaluation criterion for projection alignment, named GME, which comprises the structural similarity (SSIM) index and average phase difference (APD), is designed. Subsequently, an accurate projection alignment is achieved to estimate the drift by optimizing the GME within the proposed correction framework based on the rough-to-refined outlier elimination strategy. The simulated 2D projection alignment experiments show that the accuracy of the GME is improved by 14× and 12× than that of the mainstream feature-based methods LPM and RANSAC, respectively. The proposed method is validated through actual 3D imaging experiments.

New Constructed EEM Spectra Combined with N-PLS Analysis Approach as an Effective Way to Determine Multiple Target Compounds in Complex Samples.

Excitation-emission matrix (EEM) fluorescence spectroscopy has been applied to many fields. In this study, a simple method was proposed to obtain the new constructed three-dimensional (3D) EEM spectra based on the original EEM spectra. Then, the application of the N-PLS method to the new constructed 3D EEM spectra was proposed to quantify target compounds in two complex data sets. The quantitative models were established on external sample sets and validated using statistical parameters. For validation purposes, the obtained results were compared with those obtained by applying the N-PLS method to the original EEM spectra and applying the PLS method to the extracted maximum spectra in the concatenated mode. The comparison of the results demonstrated that, given the advantages of less useless information and a high calculating speed of the new constructed 3D EEM spectra, N-PLS on the new constructed 3D EEM spectra obtained better quantitative analysis results with a correlation coefficient of prediction above 0.9906 and recovery values in the range of 85.6-95.6%. Therefore, one can conclude that the N-PLS method combined with the new constructed 3D EEM spectra is expected to be broadened as an alternative strategy for the simultaneous determination of multiple target compounds.

3D Imaging and Quantification of the Integrin at a Single-Cell Base on a Multisignal Nanoprobe and Synchrotron Radiation Soft X-ray Tomography Microscopy.

The development of three-dimensional (3D) single-cell imaging and protein quantitative methods can provide more comprehensive information for diagnoses. We report the design and synthesis of a multisignal nanoprobe (AuGdNC@BSA-CV) for single-cell 3D imaging and quantifying the integrin αIIbß3 using correlated synchrotron radiation soft X-ray tomography microscopy and an iterative tomographic algorithm termed equally sloped tomography for the first time. Moreover, on the basis of the Au or Gd content of our nanoprobe, the number of integrin αIIbß3 on a single cell also can be accurately quantified (1.5 × 107 per cell) via inductively coupled plasma mass spectrometry.

A bidirectional scanning method for scanning transmission X-ray microscopy.

Scanning mode is a key factor for the comprehensive performance, including imaging efficiency, of scanning transmission X-ray microscopy (STXM). Herein is presented a bidirectional scanning method designed for STXM with an S-shaped moving track. In this method, artificially designed ramp waves are generated by a piezo-stage controller to control the two-dimensional scanning of the sample. The sample position information is measured using laser interferometric sensors and sent to a field-programmable gate array (FPGA) board which also acquires the X-ray signals simultaneously from the detector. Since the data recorded by the FPGA contain the real position of each scanned point, the influence of the backlash caused by the back-turning movement on the STXM image can be eliminated. By employing an adapted post-processing program, a re-meshed high-resolution STXM image can be obtained. This S-track bidirectional scanning method in fly-scan mode has been implemented on the STXM endstation at the Shanghai Synchrotron Radiation Facility (SSRF), and successfully resolved the ∼30 nm interval between the innermost strips of a Siemens star. This work removes the limitation on bidirectional scanning caused by motor backlash and vibration, and significantly improves the efficiency of STXM experiments.

Three-dimensional fast elemental mapping by soft X-ray dual-energy focal stacks imaging.

The three-dimensional (3D) dual-energy focal stacks (FS) imaging method has been developed to quickly obtain the spatial distribution of an element of interest in a sample; it is a combination of the 3D FS imaging method and two-dimensional (2D) dual-energy contrast imaging based on scanning transmission soft X-ray microscopy (STXM). A simulation was firstly performed to verify the feasibility of the 3D elemental reconstruction method. Then, a sample of composite nanofibers, polystyrene doped with ferric acetylacetonate [Fe(acac)3], was further investigated to quickly reveal the spatial distribution of Fe(acac)3 in the sample. Furthermore, the data acquisition time was less than that for STXM nanotomography under similar resolution conditions and did not require any complicated sample preparation. The novel approach of 3D dual-energy FS imaging, which allows fast 3D elemental mapping, is expected to provide invaluable information for biomedicine and materials science.

Virtual depth-scan multi-slice ptychography for improved three-dimensional imaging.

Multi-slice ptychography (MSP) is a fast three-dimensional ptychography technology developed on the basis of conventional ptychography. With this method, three-dimensional imaging can be achieved without rotating the sample. The prototype multi-slice algorithm can only reconstruct three-dimensional samples with a limited number of slices, which greatly limits the depth range and resolution of sample imaging. Here we reported a virtual depth-scan scheme of MSP in which a thick sample is scanned virtually in the depth direction across its whole thickness range within the reconstruction process, thereby eliminating the restriction on slice number and potentially improving the depth resolution of MSP. This new approach also improves the flexibility of multi-slice ptychography. Both the simulation and experimental results validate the feasibility of our new approach.

Brønsted Acid-Catalyzed Formal (3+3)-Annulation of Propargylic (Aza)-para-Quinone Methides with 4-Hydroxycoumarins and 1,3-Dicarbonyl Compounds.

Herein, we describe a highly effective 1,8-conjugate-addition-mediated formal (3+3)-annulation of (aza)-para-quinone methides in situ generated from propargylic alcohols with 4-hydroxycoumarins and 1,3-dicarbonyl compounds under the catalysis of a Brønsted acid. This methodology affords efficient and practical access to synthetically important and highly functionalized pyranocoumarins and pyrans in excellent yields under mild conditions. Importantly, these products exhibit impressive inhibitory activity toward α-glucosidase.

Formal (3 + 4)-Annulation of Propargylic p-Quinone Methides with 2-Indolylmethanols: Synthesis of Polysubstituted Indole-Fused Oxepines.

A novel Brønsted acid catalyzed 1,8-addition mediated (3 + 4)-annulation of in situ generated propargylic p-quinone methides with 2-indolylmethanols is described. This method provides a convenient and mild approach to structurally interesting and synthetically important polysubstituted indole-fused oxepines in high yields. Moreover, 2-indolylmethanols as four-atom synthons in the (3 + 4)-annulations under Brønsted acid conditions have been explored for the first time.

Dearomatization of 2,3-Disubstituted Indoles via 1,8-Addition of Propargylic (Aza)-para-Quinone Methides.

Dearomatization of indole is a useful strategy to access indolimines: a motif widely exists in biologically active molecules and natural products. Herein, an efficient method for the dearomatization of 2,3-disubstituted indoles to generate diverse indolimines with tetrasubstituted allenes is described. This work accomplishes dearomatization of 2,3-disubstituted indoles through 1,8-addition of (aza)-para-quinone methides, which are generated in situ from propargylic alcohols. A series of synthetically useful indolimines containing quaternary carbon centers and tetrasubstituted allenes can be accessed in good yields (up to 99%). Additionally, the separability of product isomers, diversified product transformations, and easy scale-up of the reaction demonstrate the potential application of this method.

Development and validation of ultra-high performance supercritical fluid chromatography method for quantitative determination of six compounds in Guizhi Fuling capsule and tablet samples.

A fast and simple ultra-high performance supercritical fluid chromatography method has been developed for the determination of six analytes, namely (paeonol, coumarin, cinnamic alcohol, cinnamic acid, paeoniflorin, and amygdalin) in Guizhi Fuling capsule and tablet samples. The influence of the key chromatographic parameters for the separation purposes was evaluated. The optimal column was Trefoil CEL1 column. The optimal mobile phase was a gradient mixture of carbon dioxide and methanol at flow rate of 1.0 mL/min. The back pressure of the system was set to 1.38 × 107  Pa and the temperature to 45°C. The six compounds were separated within 11 min by the proposed ultra-high performance supercritical fluid chromatography method with satisfactory resolution. Method validation confirmed that the procedure is accurate with the recovery rates from 87.04 to 104.30%, intraday precision values less than 4.81% and interday precision less than 5.22%, and linear with R2 higher than 0.9967. Therefore, this work provides a simple and novel method for the simultaneous analysis of six compounds in Guizhi Fuling capsule and tablet samples.

Design of an online spectrometer for the diagnosis of free-electron lasers.

A self-amplified spontaneous emission free-electron laser (FEL) is under construction at the Shanghai Soft X-ray Free-Electron Facility. Therefore, it is necessary to develop a suitable diagnostic tool capable of resolving the natural emission band of each FEL pulse. Thus, an online spectrometer with a plane mirror and plane variable-line-spacing grating at grazing incidence to monitor each single FEL pulse during the propagation of FEL radiation has been designed and is presented in this work. The method of ray tracing is used for monitoring incident radiation in order to understand spectral characteristics, and SHADOW, an X-ray optics simulation tool, and SRW, an X-ray optics wavefront tool, are applied to study the resolving power and focusing properties of the grating. The designed resolving power is ∼3 × 104 at 620 eV. Meanwhile, the effect of the actual slope error of mirrors on the ray-tracing results is also discussed. In order to provide further optimization for the choice of grating, a comparison of resolving powers between 2000 lines mm-1 and 3000 lines mm-1 gratings at different energies is analyzed in detail and radiation damage of mirrors as well as parameters such as the first-order diffraction angle ß, the exit-arm length r2, and the tilt angle θ between the focal plane and the diffraction arm are studied and optimized. This work has provided comprehensive designing methods and detailed data for the design of diagnostic spectrometers in soft X-ray FELs and will be favorable to the design of other similar instruments.

Synthesis of Naphthopyrans via Formal (3+3)-Annulation of Propargylic (Aza)-para-Quinone Methides with Naphthols.

Herein, we report an efficient Brønsted acid-catalyzed formal (3+3)-annulation of (aza)-para-quinone methides generated in situ from propargylic alcohols with naphthol derivatives, which involves a 1,8-conjugate addition/6-endo annulation process. This protocol provides an effective method for preparing important functionalized pyranocoumarins under mild conditions.

Aligning retention time shifts in HPLC three-dimensional spectra by icoshift approach combined with data arrangement methods and the release of a graphical user interface.

High-performance liquid chromatography coupled with photodiode array detection has been extensively applied in many fields and the peaks among the analyzed samples can be shifted due to the variations of instrumental and experimental conditions. In multivariate analysis, retention time alignment is an important pretreatment step. Hence, the shifted peaks in high-performance liquid chromatography coupled with photodiode array detection three-dimensional spectra should be aligned for further analysis. Being motivated by this purpose, the interval correlated shifting method combined with the proposed data arrangement methods are recommended and employed on high-performance liquid chromatography coupled with photodiode array detection data as a demonstration. We validate the alignment performance of the proposed method through comparison the consistency of the retention time before and after alignment. The obtained results demonstrated that the proposed method is capable of successful aligning the employed data. Additionally, the interval correlated shifting method combined with the data arrangement modes is implemented in an easy-to-use graphical user interface environment and so can be operated easily by users not familiar with programming languages.

Ozone pollution characteristics and sensitivity analysis using an observation-based model in Nanjing, Yangtze River Delta Region of China.

Ground-level ozone (O3) has become a critical pollutant impeding air quality improvement in Yangtze River Delta region of China. In this study, we present O3 pollution characteristics based on one-year online measurements during 2016 at an urban site in Nanjing, Jiangsu Province. Then, the sensitivity of O3 to its precursors during 2 O3 pollution episodes in August was analyzed using a box model based on observation (OBM). The relative incremental reactivity (RIR) of hydrocarbons was larger than other precursors, suggesting that hydrocarbons played the dominant role in O3 formation. The RIR values for NOX ranged from -0.41%/% to 0.19%/%. The O3 sensitivity was also analyzed based on relationship of simulated O3 production rates with reductions of VOC and NOX derived from scenario analyses. Simulation results illustrate that O3 formation was between VOCs-limited and transition regime. Xylenes and light alkenes were found to be key species in O3 formation according to RIR values, and their sources were determined using the Positive Matrix Factorization (PMF) model. Paints and solvent use was the largest contributor to xylenes (54%), while petrochemical industry was the most important source to propene (82%). Discussions on VOCs and NOX reduction schemes suggest that the 5% O3 control goal can be achieved by reducing VOCs by 20%. To obtain 10% O3 control goal, VOCs need to be reduced by 30% with VOCs/NOX larger than 3:1.

Three-dimensional focal stack imaging in scanning transmission X-ray microscopy with an improved reconstruction algorithm.

Focal stack (FS) is an effective technique for fast 3D imaging in high-resolution scanning transmission X-ray microscopy. Its crucial issue is to assign each object within the sample to the correct position along the optical axis according to a proper focus measure. There is probably information loss with previous algorithms for FS reconstruction because the old algorithms can only detect one focused object along each optical-axial pixel line (OAPL). In this study, we present an improved FS algorithm, which utilizes an elaborately calculated threshold for normalized local variances to extract multiple focused objects in each OAPL. Simulation and experimental results show its feasibility and high efficiency for 3D imaging of high contrast, sparse samples. It is expected that our advanced approach has potential applications in 3D X-ray microscopy for more complex samples.