Recyclability and Self-Healing of Dynamic Cross-Linked Polyimide with Mechanical/Electrical Damage

Recyclability and self-healing are two most critical factors in developing sustainable polymers to deal with environmental pollution and resource waste.In this work,a dynamic cross-linked polyimide insulation film with full closed-loop recyclability is successfully prepared,which also possesses good self-healing ability after being mechanical/electrical damaged depending on the Schiff base dynamic covalent bonds.The recycled and self-healed polyimide film still maintain its good tensile strength(r t)>60 MPa with Young’s modulus(E)>4 GPa,high thermal stability with glass transition temperature(T g)>220℃,and outstanding insulation property with breakdown strength(E 0)>358 kV mm^(-1),making it a very promising low energy consumption and high temperature resistant insulation material.The strategy of using Schiff base dynamic covalent bonds for reversible repairing the structure of high T g polyimides promotes the wider application of such sustainable and recyclable material in the field of electrical power and micro-electronics.

Analytical evaluation of steady-state solute distribution in through- diffusion and membrane behavior test under non-perfectly flushing boundary conditions

The through-diffusion and membrane behavior testing procedure using a closed-system apparatus has been widely used for concurrent measurement of diffusion and membrane efficiency coefficients of low-permeability clay-based barrier materials.However,the common assumption of perfectly flushing conditions at the specimen boundaries could induce errors in analyses of the diffusion coefficients and membrane efficiencies.In this study,an innovative pseudo three-dimensional(3D)analytical method was proposed to evaluate solute distribution along the boundary surfaces of the soil-porous disks system,considering the non-perfectly flushing conditions.The results were consistent with numerical models under two scenarios considering different inflow/outflow positions.The proposed model has been demonstrated to be an accurate and reliable method to estimate solute distributions along the bound-aries.The calculated membrane efficiency coefficient and diffusion coefficient based on the proposed analytical method are more accurate,resulting in up to 50%less relative error than the traditional approach that adopts the arithmetic mean value of the influent and effluent concentrations.The retar-dation factor of the clay specimen also can be calculated with a revised cumulative mass approach.Finally,the simulated transient solute transport matched with experimental data from a multi-stage through-diffusion and membrane behavior test,validating the accuracy of the proposed method.

Porphyromonas gingivalis exacerbates ulcerative colitis via Porphyromonas gingivalis peptidylarginine deiminase

Abstract:Ulcerative Colitis(UC)has been reported to be related to Porphyromonas gingivalis(P.gingivalis).Porphyromonas gingivalis peptidylarginine deiminase(PPAD),a virulence factor released by P.gingivalis,is known to induce inflammatory responses.To explore the pathological relationships between PPAD and UC,we used homologous recombination technology to construct a P.gingivalis strain in which the PPAD gene was deleted(Δppad)and aΔppad strain in which the PPAD gene was restored(comΔppad).C57 BL/6 mice were orally gavaged with saline,P.gingivalis,Δppad,or comΔppad twice a week for the entire 40 days(days 0-40),and then,UC was induced by dextran sodium sulfate(DSS)solution for 10 days(days 31-40).P.gingivalis and comΔppad exacerbated DDS-induced colitis,which was determined by assessing the parameters of colon length,disease activity index,and histological activity index,butΔppad failed to exacerbate DDS-induced colitis.Flow cytometry and ELISA revealed that compared withΔppad,P.gingivalis,and comΔppad increased T helper 17(Th17)cell numbers and interleukin(IL)-17 production but decreased regulatory T cells(Tregs)numbers and IL-10 production in the spleens of mice with UC.We also cocultured P.gingivalis,Δppad,or comΔppad with T lymphocytes in vitro and found that P.gingivalis and comΔppad significantly increased Th17 cell numbers and decreased Treg cell numbers.Immunofluorescence staining of colon tissue paraffin sections also confirmed these results.The results suggested that P.gingivalis exacerbated the severity of UC in part via PPAD.

Influence of Climatic Conditions on Planting of Hami Melon

Climate warming has made the planting area of Hami melon expand northward to Barry Bakai Town,Altay City,near 47° N. Climate events often induce the occurrence of pests and diseases in crops,affecting the steady production of Hami melon. In 2013,pests and diseases occurred seriously,resulting in low yield and poor quality of Hami melon. Based on the production survey data of Hami melon in recent20 years,the interaction of various meteorological factors in different time and different intervals of various factors was analyzed in this paper to explore the characteristics of the meteorological factors that cause diseases and influence the quality of Hami melon.

RSPSSL:A novel high-fidelity Raman spectral preprocessing scheme to enhance biomedical applications and chemical resolution visualization

Raman spectroscopy has tremendous potential for material analysis with its molecular fingerprinting capability in many branches of science and technology.It is also an emerging omics technique for metabolic profiling to shape precision medicine.However,precisely attributing vibration peaks coupled with specific environmental,instrumental,and specimen noise is problematic.Intelligent Raman spectral preprocessing to remove statistical bias noise and sample-related errors should provide a powerful tool for valuable information extraction.Here,we propose a novel Raman spectral preprocessing scheme based on self-supervised learning(RSPSSL)with high capacity and spectral fidelity.It can preprocess arbitrary Raman spectra without further training at a speed of~1900 spectra per second without human interference.The experimental data preprocessing trial demonstrated its excellent capacity and signal fidelity with an 88%reduction in root mean square error and a 60%reduction in infinite norm(L__(∞))compared to established techniques.With this advantage,it remarkably enhanced various biomedical applications with a 400%accuracy elevation(ΔAUC)in cancer diagnosis,an average 38%(few-shot)and 242%accuracy improvement in paraquat concentration prediction,and unsealed the chemical resolution of biomedical hyperspectral images,especially in the spectral fingerprint region.It precisely preprocessed various Raman spectra from different spectroscopy devices,laboratories,and diverse applications.This scheme will enable biomedical mechanism screening with the label-free volumetric molecular imaging tool on organism and disease metabolomics profiling with a scenario of high throughput,cross-device,various analyte complexity,and diverse applications.

全固态钠离子电池用聚氧化乙烯基固态聚合物电解质研究进展

钠离子电池用聚氧化乙烯(PEO)基固态电解质较有机液态电解液具有更高的安全性、柔韧性和稳定性,是最有发展前景的下一代电池技术。然而,PEO存在室温下易结晶,离子电导率低,成膜力学性能差等问题,限制了其在钠离子电池中的广泛应用。文中从钠盐选择和PEO基体改性两方面综述了钠离子电池用PEO基固态聚合物电解质在改善其离子电导率、电化学窗口和离子迁移数等性能方面的研究,并展望了其发展前景。

The dimension and morphology of alveolar bone at maxillaryanterior teeth in periodontitis: a retrospective analysis usingCBCT

The morphology of the alveolar bone at the maxillary anterior teeth in periodontitis patients was evaluated by cone-beam computed tomography(CBCT) to investigate the distribution of alveolar defects and provide guidance for clinical practice. Ninety periodontitis patients and 30 periodontally healthy individuals were selected to determine the morphology of the alveolar bone at the maxillary anterior teeth according to the degree of bone loss, tooth type, sex and age. The differences in the dimensions between periodontitis patients and healthy individuals were compared, and the distribution of alveolar bone defects was analyzed.A classification system was established regarding the sagittal positions and angulations of the teeth. The buccal residual bone was thicker and the lingual bone was thinner in the periodontitis patients than in the periodontally healthy individuals, and there were differences between the different tooth types, sexes and age subgroups. The buccal undercut was close to the alveolar ridge, while fenestration was reduced and the apical bone height was higher in periodontitis patients than in periodontally healthy individuals.The apical bone height increased with the aggravation of bone loss and age. The proportions of different sagittal positions changed with the aggravation of bone loss. Moreover, the teeth moved more buccally regarding the positions of the maxillary anterior teeth.The morphology of the alveolar bone at the maxillary anterior teeth differed between periodontitis patients and healthy individuals,and the differences were related to the degree of bone loss, tooth type, sex and age.

Numerical investigation of the effect of geosynthetic clay liner chemical incompatibility on flow and contaminant transport through a defective composite liner

A composite liner consisting of a geomembrane(GMB)and a geosynthetic clay liner(GCL)can be compromised by inorganic contaminants because of a defective GMB.When the composite liner with defective GMB is exposed to aggressive leachate conditions,the neglect of the chemical incompatibility of the GCL can potentially result in an underestimation of the leakage rate and flux through the composite liner.This paper proposed a numerical investigation on the effect of chemical incompatibility of GCL on the barrier performance of the composite liner with hole defect.Four cases with leachate solutions having varied cation valencies and ionic strengths were analyzed,in which the hydraulic conductivity of GCL was concentrationdependent.Both the effect of the chemical incompatibility of GCL and the mechanisms were analyzed.The incompatibility of GCL resulted in significant increases in leakage rate and flux through the composite liner by factors of up to 4.9 and 5.0,respectively.The incompatibility-affected area in GCL is located within 0.1 m from the center of the hole in the GMB.The coupled increase in the hydraulic conductivity of GCL and pore water concentration impacts the flux and leakage in a short period of time.With GCL chemical incompatibility considered,advection may dominate the contaminant transport through GCL.

Lipid droplets as endogenous intracellular microlenses

Using a single biological element as a photonic component with well-defined features has become a new intriguing paradigm in biophotonics.Here we show that endogenous lipid droplets in the mature adipose cells can behave as fully biocompatible microlenses to strengthen the ability of microscopic imaging as well as detecting intra-and extracellular signals.By the assistance of biolenses made of the lipid droplets,enhanced fluorescence imaging of cytoskeleton,lysosomes,and adenoviruses has been achieved.At the same time,we demonstrated that the required excitation power can be reduced by up to 73%.The lipidic microlenses are finely manipulated by optical tweezers in order to address targets and perform their real-time imaging inside the cells.An efficient detecting of fluorescence signal of cancer cells in extracellular fluid was accomplished due to the focusing effect of incident light by the lipid droplets.The lipid droplets acting as endogenous intracellular microlenses open the intriguing route for a multifunctional biocompatible optics tool for biosensing,endoscopic imaging,and single-cell diagnosis.

Synthesis of arylsulfonyl-substituted indolo[2,1-a]isoquinolin-6(5H)-one derivatives via a TBAI-catalyzed radical cascade cyclization

We have developed a metal-free radical cascade reaction of N-substituted 2-aryl indoles with readily available sulfonyl hydrazides for the rapid construction of arylsulfonyl-substituted indolo[2,1-a]isoquinolin-6(5H)-one derivatives.With the TBAI–TBHP catalytic system,a broad series of structurally diverse indolo[2,1-a]isoquinolin-6(5H)-one derivatives were obtained in moderate to excellent yields.The reaction features mild reaction conditions,operationally easiness,scaled-up feasibility,and high functional-group-tolerance.

Preparation of shape-controlling V0_(2)(M/R)nanoparticles via one-step hydrothermal synthesis

In this study,we developed a facile one-step hydrothermal process that allows to synthesize high-purity V0_(2)(M/R)nanoparticles with various morphologies such as nanorods,nanogranules,nanoblocks,and nanospheres.W dopants are successfully implanted in V02(M/R)unit cells with high doping efficiency,which allows to regulate the size,morphology,and phase of obtained nanoparticles.The underlying regulation mechanism is presented in detail to reveal how hydrothermal products vary with W doping contents,which provides a synthetic strategy for the preparation of shape-controlling V02(M/R)nanoparticles with high purity to satisfy different specific demands for corresponding applications in the field of thermochromic smart windows.

Molecular force mechanism of hydrodynamics in clay nanopores

Nanopores are prevalent within various clay morphologies,and water flow in clay nanopores is significant for various engineering applications.In this study,we performed non-equilibrium molecular dynamics(NEMD)simulations to reveal the molecular force mechanisms of water flow in clay nanopores.The water dynamic viscosity,slip length,and average flow velocity were obtained to verify the NEMD models.Since the water confined in the nanopores maintained a dynamic mechanical equilibrium state,each water lamina can be regarded as a simply supported beam.The applied driving force,the force from clay crystal layers,the force from compensating sodium ions,and the force from other water laminae were further calculated to investigate the force mechanisms.The van der Wals barrier above the surface and hydraulic gradient lead to distribution differences in water oxygen atoms,which contribute to a net van der Waals resistance component of the force from clay crystal layers.Meanwhile,the water molecules tend to rotate to generate the electrostatic resistance component of the force from clay crystal layers and balance the increasing hydraulic gradient.Due to the velocity difference,the water molecules in the slower lamina have a higher tendency to lag and generate a net electrostatic resistance force as well as a net van der Waals driving force on the water molecules in the faster lamina,which together make up the viscous force.

Single-cell biomagnifier for optical nanoscopes and nanotweezers

Optical microscopes and optical tweezers,which were invented to image and manipulate microscale objects,have revolutionized cellular and molecular biology.However,the optical resolution is hampered by the diffraction limit;thus,optical microscopes and optical tweezers cannot be directly used to image and manipulate nano-objects.The emerging plasmonic/photonic nanoscopes and nanotweezers can achieve nanometer resolution,but the high-index material structures will easily cause mechanical and photothermal damage to biospecimens.Here,we demonstrate subdiffraction-limit imaging and manipulation of nano-objects by a noninvasive device that was constructed by trapping a cell on a fiber tip.The trapped cell,acting as a biomagnifier,could magnify nanostructures with a resolution of 100 nm(λ/5.5)under white-light microscopy.The focus of the biomagnifier formed a nano-optical trap that allowed precise manipulation of an individual nanoparticle with a radius of 50 nm.This biomagnifier provides a high-precision tool for optical imaging,sensing,and assembly of bionanomaterials.

Targeted metabolomics of sulfated bile acids in urine for the diagnosis and grading of intrahepatic cholestasis of pregnancy

Intrahepatic cholestasis of pregnancy(ICP)is related to cholestatic disorder in pregnancy.Total urinary sulfated bile acids(SBAs)were found increased in ICP.We distinguished the metabolic profiling of urinary SBAs in ICP to find potential biomarkers for the diagnosis and grading of ICP.The targeted metabolomics based on high-performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS)was used to analyze urinary SBAs profiling in mild and severe ICP cases,as well as healthy controls.16 kinds of urinary SBAs were determined by HPLC-MS/MS.Sulfated dihydroxy glycine bile acid(di-GBA-S),glycine cholic acid 3-sulfate(GCA-3S),sulfated dihydroxy taurine bile acid(di-TBA-S)and taurine cholic acid 3-sulfate(TCA-3S)increased significantly in ICP group compared with the control group.Seven kinds of SBAs were significantly different(p<0.05)between the ICP group and the control group,with the variable importance in the projection(VIP)value more than one by the orthogonal partial least squares discriminant analysis(OPLS-DA).GCA-3S was well-suited to be used as the biomarker for the diagnosis of ICP with the sensitivity of 100%and specificity of 95.5%.A multi-variable logistic regression containing GCA-3S and di-GBA-S-1 was constructed to distinguish severe ICP from mild ICP,with the sensitivity of 94.4%and specificity of 100%.The developed HPLC-MS/MS method is suitable for the measurement of urinary SBAs profiling.Moreover,the urinary SBAs in the metabolomic profiling have the potential to be used as non-intrusive biomarkers for the diagnosis and grading of ICP.

氧化酯化反应催化剂的研究进展

本工作综述了近年来醛或醇氧化酯化催化剂的研究进展,介绍了均相催化剂和非均相催化剂的研究情况,其中均相反应体系,催化剂不易分离且能耗较大,价格普遍偏高,适用于氧化酯化的均相反应体系难以工业化。非均相反应体系在工业化方面具有很大优势,催化剂分离简单易还原、可回收再利用等,但同样存在稳定性较差及收率较低的问题。分析了贵金属催化剂和非贵金属催化剂的合成、结构及催化醛氧化酯化性能,总结了部分催化剂催化醛氧化酯化的反应机理。通过各种制备方法调控催化剂的结构、形貌、比表面积,进而暴露大面积活性面及延长催化剂的使用寿命来提高催化剂的经济效益。展望了氧化酯化反应催化剂的研究方向,贵金属催化剂由于成本限制,非贵金属催化剂将是未来醛氧化酯化领域重点研究的方向。要点:(1)综述了醛与醇一步氧化酯化催化剂的研究进展。(2)重点介绍了均相催化剂与非均相催化剂的研究情况。(3)展望了氧化酯化反应催化剂的研究方向。

Subwavelength imaging and detection using adjustable and movable droplet microlenses

We developed adjustable and movable droplet microlenses consisting of a liquid with a high refractive index.The microlenses were prepared via ultrasonic shaking in deionized water,and the diameter of the microlenses ranged from 1 to 50μm.By stretching the microlenses,the focal length can be adjusted from 13 to 25μm.With the assistance of an optical tweezer,controllable assembly and movement of microlens arrays were also realized.The results showed that an imaging system combined with droplet microlenses could image 80 nm beads under white light illumination.Using the droplet microlenses,fluorescence emission at 550 nm from Cd Se@Zn S quantum dots was efficiently excited and collected.Moreover,Raman scattering signals from a silicon wafer were enhanced by^19 times.The presented droplet microlenses may offer new opportunities for flexible liquid devices in subwavelength imaging and detection.

Phenoxazine-based supramolecular tetrahedron as biomimetic lectin for glucosamine recognition

The design and synthesis of a phenoxazine-based metal-organic tetrahedro n(Zn4L4) as biomimetic lectin for selectively recognition of glucosamine(GlcN) was reported.Different from the free phenoxazinebased ligand(L),Zn4L4 displayed the highest fluorescent intensity enhancement efficiency toward GlcN over other related natural mono-and disaccharides.Fluorescence titration demonstrated a 1:1 stoichiometric host-guest complex was formed with an association constant about 4.03 × 104 L/mol.1H NMR spectroscopic studies confirmed this selectivity resulted from the multiple hydrogen bonding interactions formed between GlcN and Zn4L4.The present results suggested that rational arrangement of recognition sites in the confined space of metal-organic cage is crucial for the selectivity toward target guests.