Behavior and Quantification Studies of Phoxim Pesticide Using Cyclic and Linear Sweep Stripping Voltammetry at a Mercury Electrode

The adsorptive and electrochemical behaviour of phoxim on a hanging mercury drop electrode were explored in NH3·H2O-NH4Cl buffer by using cyclic and linear sweep voltmmetry. The procedure was successfully applied for the assay of phoxim in vegetable and fruit samples.

In vivo 3-photon fluorescence microscopy of white matter in mouse brain excited at the 1700 nm window

White matter,a densely packed collection of myelinated axons,plays an essential part in neural networks.With high spatial resolution and deep penetration,multi-photon microscopy(MPM)is promising for white matter imaging in animal models in vivo.The third harmonic generation(THG)signal can be generated from white matter,but the bottom part of the white matter layer generates weak THG due to its high scattering.Here,we demonstrate an in vivo labeling and imaging technology,capable of visualizing the white matter layer in the mouse brain,combining°uorescence labeling with MitoTracker Red and three-photon°uorescence(3PF)microscopy excited at the 1700 nm window.3PF signals are several times higher than THG signals,resulting in deeper imaging of the white matter layer with the former.Our results indicate that 3PF microscopy is a promising technology for white matter imaging in the deep brain in vivo.

In vivo label-free measurement of blood flow velocity symmetry based on dual line scanning third-harmonic generation microscopy excited at the 1700 nm window

Measurement of bloodflow velocity is key to understanding physiology and pathology in vivo.While most measurements are performed at the middle of the blood vessel,little research has been done on characterizing the instantaneous bloodflow velocity distribution.This is mainly due to the lack of measurement technology with high spatial and temporal resolution.Here,we tackle this problem with our recently developed dual-wavelength line-scan third-harmonic generation(THG)imaging technology.Simultaneous acquisition of dual-wavelength THG line-scanning signals enables measurement of bloodflow velocities at two radially symmetric positions in both venules and arterioles in mouse brain in vivo.Our results clearly show that the instantaneous bloodflow velocity is not symmetric under general conditions.

MicroRNA-21、microRNA-137和microRNA-498在肺腺癌患者血清中表达情况及其临床意义

目的研究肺腺癌相关MicroRNAs在正常人群及肺腺癌患者血清中的表达情况,分析其在肺腺癌诊断中的临床价值。方法收集59例肺腺癌及40例正常体检人群血清,通过实时荧光定量聚合酶链反应(qRT-PCR)检测各组miR-498、miR-21、miR-137、miR-206、miR-138、miR-32及miR-125b的表达情况。统计分析两组之间miRNA的表达差异以及单个血清miRNA在肺腺癌诊断中的价值,进一步用统计学方法分析多个miRNAs联合检测的诊断价值。结果相比正常体检人群,肺腺癌患者血清中miR-498、miR-21和miR-137表达增加,差异有统计学意义(P<0.05);两组miR-206、miR-138、miR-32及miR-125b的表达量比较,差异无统计学意义。AUC曲线分析结果显示,miR-498的AUC为0.73(95%CI,0.63~0.81),miR-21的AUC为0.83(95%CI,0.74~0.90),miR-137的AUC为0.74(95%CI,0.64~0.82)。miR-498、miR-21联合miR-137在肺腺癌诊断中AUC值为0.93(95%CI,0.85~0.97),3者联合优于单个miRNA任一检测,差异有统计学意义(P<0.05)。结论 miR-498、miR-21和miR-137在肺腺癌患者血清中升高,血清中miR-498、miR-21和miR-137在肺腺癌的诊断中具有潜在的应用价值。

Determination of Critical Influencing Factor on pH Stability of Yuxingcao Injection

The change of drug quality of Yuxingcao injection after formulation is considered as one of the causes for adverse reactions. In this study, orthogonal experimental design was used to investigate the influencing factors on the pH stability of Yuxingcao injection. Two methods of accelerated tests were carried out in the experiments. The results showed that using Tween 80 as the solubilizer could significantly decrease the pH value of Yuxingcao injection after accelerated tests. There was no significant difference in the pH value after the accelerated tests when the other 6 factors varied, including the type of liquid processed, the dosage of activated carbon, heating temperature, reagents for pH adjustment, pH value range after adjustment, and sterilization conditions. In order to improve the quality stability of Yuxingcao injection, the quality of Tween 80 should be strictly controlled to minimize the change of pH value of Yuxingcao injection.

Sinomenine Purification by Continuous Liquid-Liquid Extraction Process with Centrifugal Extractors

Continuous manufacturing is considered as one of the future trends of pharmaceutical engineering. In this work, continuous liquid-liquid extraction for sinomenine purification was realized with the usage of centrifugal extractors. Chloroform was used as the extractant because of the high distribution coefficient (>100). Higher extraction ratio can be obtained when using the centrifugal extractor of Model CWL50-N. The extraction ratio of the second-stage extraction was higher than that of the first-stage extraction. The extraction ratio of the second-stage countercurrent extraction was higher than that of second-stage cross-flow extraction. When chloroform phase was recycled for liquid-liquid extraction, the extraction ratio was also higher than 95%. This work can also be an example of continuous liquid-liquid extraction for the separation of other Chinese medicine components.

吲哚美辛、生长抑素单用或联用使用的选择适应征及其对高风险ERCP患者术后胰腺炎的预防作用

背景内镜逆行性胰胆管造影(endoscopic retrograde cholan-giopancreatography,ERCP)术是一项广泛且重要的诊治胆道及其胰腺微创技术,但部分患者会在术后出现胰腺炎(post-ERCP pancreatitis,PEP).生长抑素和吲哚美辛预防PEP的经典药物,学者们对生长抑素、吲哚美辛单用或联用仍存在争议.目的探讨吲哚美辛、生长抑素单用或联用使用的选择适应征及其对高风险ERCP患者PEP的预防作用.方法前瞻性分析2017-01/2020-12我院行高风险ERCP治疗的患者729例,按析因设计随机分为4组:空白组;吲哚美辛组;生长抑素组;吲哚美辛+生长抑素组.分析4组ERCP术后高淀粉酶血症、PEP、术后6 h、12 h、24 h VAS疼痛评分、肿瘤坏死因子α(TNF-α)、白细胞介素6(IL-6)、IL-8浓度和副反应发生率.结果与空白对照组比较,吲哚美辛组PEP发生率、住院成本和住院时间差异无统计学意义,高淀粉酶血症发生率和术后6 h内VAS疼痛评分显著性降低、术后TNF-α、IL-6和IL-8浓度均显著性降低.与空白对照组和吲哚美辛组比较,生长抑素组住院成本、住院时间、高淀粉酶血症发生率、PEP发生率、术后6 h、12 h、24 h各时间点VAS疼痛评分及术后TNF-α、IL-6和IL-8浓度均显著性降低.与吲哚美辛组比较,吲哚美辛+生长抑素组住院成本、住院时间、高淀粉酶血发生率、PEP发生率、术后6 h、12 h、24 h时间点VAS疼痛评分显著性降低、术后TNF-α、IL-6和IL-8浓度均显著性降低.与生长抑素组比较,吲哚美辛+生长抑素组PEP发生率、住院成本和住院时间差异无统计学意义,但高血淀粉酶发生率和术后6 h内VAS疼痛评分、TNF-α、IL-6和IL-8浓度均显著性降低,而术后12 h至24 hVAS、TNF-α、IL-6和IL-8浓度比较差异无统计学意义.结论对于高风险ERCP患者,吲哚美辛能降低术后高淀粉酶血症发生率,改善短时间内的患者生活质量,适合于ERCP操作过程较简单、时间较短、预计术后腹痛程度较轻、时间较短的患者.生长抑素能降低术后高淀粉酶血症发生率,改善较长时间内的患者生活质量和PEP发生率,降低住院成本,适合于ERCP操作过程较复杂、时间较长、预计术后腹痛程度较重、时间较长的患者.二者联用在术后6 h内对于降低高淀粉酶血症发生率、改善患者生活质量具有交互作用,适合于ERCP操作过程更复杂、操作时间更长、预计术后腹痛程度更重的患者.

3-photon fluorescence and third-harmonic generation imaging of myelin sheaths in mouse digital skin in vivo:A comparative study

Myelin sheaths wrapping axons are key structures that help maintain the propagation speed of action potentials in both central and peripheral nervous systems(CNS and PNS).However,noninvasive,deep imaging technologies visualizing myelin sheaths in the digital skin in vivo are lacking in animal models.3-photon°uorescence(3PF)imaging excited at the 1700-nm window enables deep imaging of myelin sheaths,but necessitates labeling by exogenous°uorescent dyes.Since myelin sheaths are lipid-rich structures which generate strong third-harmonic signals,in this paper,we perform a detailed comparative experimental study of both third-harmonic generation(THG)and 3PF imaging in the mouse digital skin in vivo.Our results show that THG imaging also enables visualization of myelin sheaths deep in the mouse digital skin,which shows colocalization with 3PF signals from labeled myelin sheaths.Besides its superior label-free advantage,THG does not su®er from photobleaching due to its 3PF property.

Deep-skin third-harmonic generation(THG)imaging in vivo excited at the 2200 nm window

The skin is heterogeneous and exerts strong scattering and aberration onto excitation light in multiphoton microscopy(MPM).Shifting to longer excitation wavelengths may help reduce skin scattering and aberration,potentially enabling larger imaging depths.However,previous demonstrations of skin MPM employ excitation wavelengths only up to the 1700 nm window,leaving an open question as to whether longer excitation wavelengths are suitable for deep-skin MPM.Here,in order to explore the longer-wavelength territory,first,we demonstrate characterization of the broadband transmittance of excised mouse skin,revealing a high transmittance window at 2200nm.Then,we demonstrate third-harmonic generation(THG)imaging in mouse skin in vivo excited at this window.With 9mW optical power on the skin surface operating at 1MHz repetition rate,we can get THG signals of 250
m below the skin surface.Comparative THG imaging excited at the 1700nm window shows that as imaging depth increases,THG signals decay even faster than those excited at 2200 nm.Our results thus uncover the 2200 nm window as a new,promising excitation window potential for deep-skin MPM.

A dual-signal sensor for the analysis of parathion-methyl using silver nanoparticles modified with graphitic carbon nitride

A highly sensitive and selective method was developed for both UVevis spectrophotometric and fluorimetric determination of organophosphorus pesticides(OPs). This method used silver nanoparticles(AgNPs) modified with graphitic carbon nitride(g-C_3N_4). The AgNPs reduced the fluorescence intensity of g-C_3N_4. Acetylthiocholine(ATCh) could be catalytically hydrolyzed by acetylcholinesterase(AChE) to form thiocholine, which induces aggregation of the AgNPs. This aggregation led to the recovery of the blue fluorescence of g-C_3N_4, with excitation/emission peaks at 310/460 nm. This fluorescence intensity could be reduced again in the presence of OPs because of the inhibitory effect of OPs on the activity of AChE. The degree of reduction was found to be proportional to the concentration of OPs, and the limit of fluorometric detection was 0.0324 mg/L(S/N=3). In addition, the absorption of the g-C_3N_4/AgNPs at 390 nm decreased because of the aggregation of the AgNPs, but was recovered in presence of OPs because of the inhibition of enzyme activity by OPs. This method was successfully applied to the analysis of parathion-methyl in real samples.

Comparison of the emission wavelengths by a single fluorescent dye on in vivo 3-photon imaging of mouse brains

Multiphoton microscopy(MPM)is a powerful imaging technology for brain research.The imaging depth in MPM is partly determined by emission wavelength of fluorescent labels.It has been demonstrated that a longer emission wavelength is favorable for signal detection as imaging depth increases.However,there has been no comparison with near-infrared(NIR)emission.In order to quantitatively analyze the effect of emission wavelength on 3-photon imaging of mouse brains in vivo,we utilize the same excitation wavelength to excite a single fluorescent dye and simultaneously collect NIR and orange-red emission fluorescence at 828 nm and 620 nm,respectively.Both experimental and simulation results show that as the imaging depth increases,NIR emission decays less than orange-red fluorescent emission.These results show that it is preferable to shift the emission wavelength to NIR to enable more e±cient signal collection deep in the brain.

Multiscale strain alleviation of Ni-rich cathode guided by in situ environmental transmission electron microscopy during the solid-state synthesis

Ni-rich layered oxides are one of the most promising cathode materials for Li-ion batteries due to their high energy density.However,the chemomechanical breakdown and capacity degradation associated with the anisotropic lattice evolution during lithiation/delithiation hinders its practical application.Herein,by utilizing the in situ environmental transmission electron microscopy(ETEM),we provide a real time nanoscale characterization of high temperature solid-state synthesis of LiNi_(0.8)CO_(0.1)Mn_(0.1)O_(2)(NCM811) cathode,and unprecedentedly reveal the strain/stress formation and morphological evolution mechanism of primary/second ary particles,as well as their influence on electrochemical performance.We show that stress inhomogeneity during solid-state synthesis will lead to both primary/secondary particle pulverization and new grain boundary initiation,which are detrimental to cathode cycling stability and rate performance.Aiming to alleviate this multiscale strain during solid-state synthesis,we introduced a calcination scheme that effectively relieves the stress during the synthesis,thus mitigating the primary/secondary particle crack and the detrimental grain boundaries formation,which in turn improves the cathode structural integrity and Li-ion transport kinetics for long-life and high-rate electrochemical performance.This work remarkably advances the fundamental understanding on mechanochemical properties of transition metal oxide cathode with solid-state synthesis and provides a unified guide for optimization the Ni-rich oxide cathode.

Determination of ziram in vegetable samples by square wave voltammetry

The electrochemical behaviour and electrode reaction mechanism of ziram （zinc-dimethyl dithiocarbamate） on a hanging mercury drop electrode were investigated in Britton-Robinson （B-R） buffer by using cyclic and square wave voltammetry （SWV）. Based on these studies a voltammetric method for determination of ziram wasdeveloped and applied to determine the ziram in synthetic and spiked vegetable samples, satisfactory results were obtained in both cases.

Degradation of multiphoton signal and resolution when focusing through a planar interface with index mismatch:Analytical approximation and numerical investigation

Multiphoton microscopy(MPM)is an invaluable tool for visualizing subelllar structures in biomedical and life sdences.High-numerical-aperture(NA)immersion objective lenses are used to deliver excitation light to focus inside the biological tissue.The refractive index of tissue is commonly different from that of the immersion medium,which introduces spherical aberration,leading to signal and resolution degradation as imaging depth increases.However,the explicit dependence of this index mismatch induced aberration on the involved physical parameters is not dlear,espeially its dependence on index mismatch.Here,from the vectorial equations for fo-cusing through a planar interface bet ween materials of mismatched refractive indices,we derive an approximate analytical expression for the spherical aberration.The analytical expression explicitly reveals the dependence of spherical aberration on index mismatch,imaging depth and excitation wavelength,from which we can expect the following qualitative behaviors:(1)Mul-tiphoton sigmal and resolution degradation is less for longer excitation wavelength,(2)a longer wavelength tolerates a higher index mismatch,(3)a longer wavelength tolerates a larger imaging depth and(4)both signal and resohution degradations show the same dependence om imaging depth,regardless of NA or immersion on the condition that the integration angle is the same.Detailed numerical simulation results agree quite well with the above expectations based on the analytical approximation.These theoretical results suggest the use of long excitation wavelength to better suppress index mismatch.induced sigmal and resolution degradation in deep-tssue MPM.

Estimation of temperature rise at the focus of objective lens at the 1700 nm window

Optical microscopy of biological tissues at the 1700 nm window has enabled deeper penetration,due to the combined advantage of relatively small water absorption and tissue scattering at this wavelength.Compared with excitation at other wavelengths,such as the commonly used 800 nm window for two-photon microscopy,water absorption at the 1700nm window is more than one order of magnitude higher.As a result,more temperature rise can be expected and can be potentially detrimental to biological tissues.Here,we present theoretical estimation of temper-ature rise at the focus of objective lens at the 1700nm window,purely due to water absorption.Our calculated result shows that under realistic experimental conditions,temperature rise due to water absorption is still below 1 K and may not cause tissue damage during imaging.

Photodetection-induced relative timing jitter in synchronized time-lens source for coherent Raman scattering microscopy

Synchronized time lens source is a novel method to generate synchronized optical pulses to mode-locked lasers,and has found widespread applications in coberent Raman scattering microscopy.Relative timing jitter between the mode-locked laser and the synchronized time-lens source is a key parameter for evaluating the synchronization peformance of such synchronized laser sys-tems.However,the origins of the relative timing jitter in such systens are not fully determined,which in turn prevents the experimental efforts to optimize the synchronization perfornance.Here,we demonstrate,through theoretical modeling and mumerical simulation,that the photo-detction could be one physical origin of the relative timing jitter.Comparison with relative timing jitter due to the intrinsic timing jitter of the mode-locked laser is also demonstrated,revealing different qualitative and quantitative behavios.Based on the nature of this photo-detection-induced timing jitter,we further propose several strategies to reduce the relative timing jitter.Our thoretical results will provide guidelines for optimizing synchronization performance in experiments.

Establishment and characterization of an oxaliplatin-resistant hepatic cancer cell line

Objective The aim of the current study was to establish an oxaliplatin-resistant hepatoma cell line(HepG2/OXA) and investigate the potential mechanisms of its drug resistance.Methods The hepatoma cell subline, HepG2/OXA, resistant to oxaliplatin(OXA), was established from a parent cell line HepG2, by stepwise exposure to gradually increasing concentrations of OXA over a half-year period. Chemosenstivity of the cytotoxic drugs, OXA, cisplatin(CDDP), adriamycin(ADM), and 5-fuorouracil(5-FU), was determined in HepG2 and HepG2/OXA cells, by the Cell counting kit-8(CCK8) assay. Cell cycle distribution of HepG2 and HepG2/OXA cells was analyzed by Flow cytometry(FCM). The expression levels of several drug resistance-related proteins, such as P-glycoprotein(P-gp), multidrug resistant protein 1(MRP1), and excision repair-cross complementing 1(ERCC1) protein in the two cell lines were tested by the western blot assay.Results The IC50 of OXA in HepG2/OXA and HepG2 were 136.84 μmol/L and 23.86 μmol/L, respectively. The resistance index(RI) was 5.34. HepG2 was also demonstrated to be cross-resistant to other antitumor agents, such as 5-FU, ADM, and CDDP. The percentage of HepG2/OXA cells in the S phase was significantly decreased compared to HepG2 cells(25.58% ± 2.36% vs 14.37% ± 2.54%, P < 0.05), while the percentage of cells in the G0/G1 and G2/M phases showed no statistical difference(respectively 55.29% ± 4.98% vs 56.73% ± 4.56%, P > 0.05, and 24.63% ± 4.81% vs 28.26% ± 3.82%, P > 0.05). The ERCC1 was found to be over expressed in HepG2/OXA cells, while there was no difference in the expressions of P-gp and MRP1 between the multiple drug resistance(MDR) phenotype cell line and its parental cell line.Conclusion HepG2/OXA showed an MDR ability; the over expression of ERCC1 might be associated with the platinum resistance of the cells, but P-gp and MRP1 are not.

Application of artificial neural networks to the determination of pesticides by linear sweep stripping voltammetry

In this work, artificial neural network （ANN）, a powerful chemometrics approach for linear and nonlinear calibration models, was applied to detect three pesticides in mixtures by linear sweep stripping voltammetry （LSSV） despite their overlapped voltammograms. Electrochemical parameters for the voltammetry, such as scan rate, deposit time and deposit potential, were evaluated and optimized from the signal response data using ANN model by minimizing the relative prediction error （RPE）. The proposed method was successfully applied to the detection of pesticides in synthetic samples and several commercial fruit samples.

Enhanced electrochemical performance of nanoscale single crystal NMC811 modification by coating LiNbO_(3)

Single crystallization is an important strategy to resolve intergranular cracks and unnecessary side reactions with electrolytes in layered transition metal oxide cathodes LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)(NMC811).Due to the limitations of high-temperature sintering and multi-step calcination,single crystal NMC811 generally shows irregular particles with a size of 2-3μm.However,the prolonged Li-ion diffusion pathway and the stress generated by the uneven de-/intercalation sluggish Li-ion diffusion kinetics,what is more,cause structural damage such as intragranular cracks.A slow Li extraction rate or particle size reduction will ameliorate the structural damage and improve the cycling stability.As the most promising cathodes for next-generation power batteries,NMC811 required fast charge performance and cycle stability.Particle size reduction appears to be the displacement option.Nanonization is an effective strategy to mitigate intragranular cracks of single crystal NMC811.However,the serious aggregation and increased specific surface area become new challenges.In this article,we synthesized monodisperse nanoscale single crystal NMC811 by molten salt method and modified the surface by LiNbO3 coating.The electrochemical performance shows that nanoscale single crystal NMC811 has faster kinetic and higher capacity retention,so the strategy of combining nanonization and surface coating is an alternative way to prepare high specific capacity and cycle stable single crystal NMC811.

Selective laser melting of NiTi alloy with superior tensile property and shape memory effect

It is a challenge to develop complex-shaped Ni Ti shape memory alloy parts by traditional processing methods, due to the poor machinability of Ni Ti alloy. It is reported that selective laser melting(SLM) of additive manufacturing could overcome this problem. However, the reported SLM-produced Ni Ti exhibits poor tensile ductility due to the inner defects and adverse unidirectional columnar grains from SLM process. In this work, the defect-less SLM-Ni Ti with nondirective columnar grains was fabricated by optimizing the intraformational laser scanning length and interformational laser scanning direction. The obtained lath-shaped SLM-Ni Ti sample exhibits tensile strain of 15.6%, more than twice of the reported maximum result(7%). Besides, the SLM-Ni Ti part with complex geometry displays a shape memory recovery of 99% under compressive deformation of 50%.