Determination of inhibitory activity of Salvia miltiorrhiza extracts on xanthine oxidase with a paper-based analytical device

A novel paper-based analytical device(PAD)was prepared and applied to determine the xanthine oxidase(XOD)inhibitory activity of Salvia miltiorrhiza extracts(SME).First,polycaprolactone was 3D printed on filter paper and heated to form hydrophobic barriers.Then the modified paper was cut according to the specific design.Necessary reagents including XOD for the colorimetric assay were immobilized on two separate pieces of paper.By simply adding phosphate buffer,the reaction was performed on the double-layer PAD.Quantitative results were obtained by analyzing the color intensity with the specialized device system(consisting of a smartphone,a detection box and sandwich plates).The 3Dprinted detection box was small,with a size of 9.0 cm×7.0 cm×11.5 cm.Color component G performed well in terms of linearity and detection limits and thus was identified as the index.The reaction conditions were optimized using a definitive screening design.Moreover,a 10%glycerol solution was found to be a suitable stabilizer.When the stabilizer was added,the activity of XOD could be maintained for at least 15 days under 4℃ or-20℃ storage conditions.The inhibitory activity of SME was investigated and compared to that of allopurinol.The results obtained with the PAD showed agreement with those obtained with the microplate method.In conclusion,the proposed PAD method is simple,accurate and has a potential for point-of-care testing.It also holds promise for use in rapid quality testing of medicinal herbs,intermediate products,and preparations of traditional Chinese medicines.

A Smartphone-assisted Paper-based Analytical Device for Fluorescence Assay of Hg2+

Rapid,efficiency and portable detection systems in low-resource settings with limited laboratory equipment and technical expertise are urgently needed.Herein,an integrated platform composed of a paper-based analytical device and a smartphone detection system for Hg^2+ onsite testing was developed.Nitrogen-doped carbon dots(N-CDs)were synthesized by a simple hydrothermal method using citric acid as the carbon source and ethanediamine as the nitrogen source,which gave out bright blue fluorescence under the excitation at 350 nm UV light and the absolute fluorescence quantum yield was 17.1%.The fluorescence of the prepared N-CDs can be effectively quenched by Hg^2+.In addition,an external attachment of smartphone for illumination and external light interference was designed to trace the fluorescence signals,and a software application of Android system with simple operation program was developed to perform snapshot and image processing.The smartphone-assisted detection system was combined with the N-CDs decorated paper chip to achieve the sensitive detection of Hg^2+ in water samples.This integrated method for reliable sensing of Hg^2+ shows a good linear detection range of 10–800μmol/L(R2=0.9595)with detection limit of 1.07×10^?8 mol/L.

Analytical method of radiation by a wave energy device with dual rectangular floating bodies

The system with one floating rectangular body on the free surface and one submerged rectangular body has been applied to a wave energy conversion device in water of finite depth. The radiation problem by this device on a plane incident wave is solved by the use of an eigenfunction expansion method, and a new analytical expression for the radiation velocity potential is obtained. The wave excitation force is calculated via the known incident wave potential and the radiation potential with a theorem of Haskind employed. To verify the correctness of this method, an example is computed respectively through the bound element method and analytical method. Results show that two numerical methods. are in good agreement, which shows that the present method is applicable. In addition, the trends of hydrodynamic coefficients and wave force are analyzed under different conditions by use of the present analytical method.

Fabrication of paper-based devices for in vitro tissue modeling

Paper devices have recently attracted considerable attention as a class of cost-effective cell culture substrates for various biomedical applications.The paper biomaterial can be used to partially mimic the in vivo cell microenvironments mainly due to its natural three-dimensional characteristic.The paper-based devices provide precise control over their structures as well as cell distributions,allowing recapitulation of certain interactions between the cells and the extracellular matrix.These features have shown great potential for the development of normal and diseased human tissue models.In this review,we discuss the fabrication of paper-based devices for in vitro tissue modeling,as well as the applications of these devices toward drug screening and personalized medicine.It is believed that paper as a biomaterial will play an essential role in the field of tissue model engineering due to its unique performances,such as good biocompatibility,eco-friendliness,cost-effectiveness,and amenability to various biodesign and manufacturing needs.

Literature Review of the Use of Zinc and Zinc Compounds in Paper-Based Microfluidic Devices

Zinc and its compounds, alloys and composites play an important role in the modern day world and find application in almost every aspect that can improve the quality of our lives. This ranges from supplements and pharmaceuticals that are meant to improve our health and wellbeing to additives meant to guard or reduce corrosion in metals. However, over the past several years, a new area of technology has been garnering a great deal of attention and has made use of zinc and its compounds. This is with reference to paper-based microfluidic technology that offers several advantages and that keeps expanding in the amount of applications it covers. In this paper, a review is offered for the applications that have used zinc or zinc compounds in paper-based microfluidic devices.

Thermoelastic stress analysis of multilayered films in a micro-thermoelectric cooling device

This paper presents an analytical solution for the thermoelastic stress in a typical in-plane＇s thin-film micro- thermoelectric cooling device under different operating con- ditions. The distributions of the permissible temperature fields in multilayered thin-films are analytically obtained, and the characteristics, including maximum temperature dif- ference and maximum refrigerating output of the thermo- electric device, are discussed for two operating conditions. Analytical expressions of the thermoelastic stresses in the layered thermoelectric thin-films induced by the tempera- ture difference are formulated based on the theory of mul- tilayer system. The results demonstrate that, the geometric dimension is a significant factor which remarkably affects the thermoelastic stresses. The stress distributions in layers of semiconductor thermoelements, insulating and support- ing membrane show distinctly different features. The present work may profitably guide the optimization design of high- efficiency micro-thermoelectric cooling devices.

Application of the state space model to the system of wave energy conversion Analytical method for wave forces on singleoscillating rectangular buoy

A new analytical method is proposed to analyze the force acting on a rectangular oscillating buoy due to linear waves.In the method a new analytical expression for the diffraction velocity potential is obtained first by use of theeigenfunction expansion method and then the wave excitation force is calculated by use of the known incident wavepotential and the diffraction potential. Compared with the classical analytical method, it can be seen that the presentmethod is simpler for a two-dimensional problem due to the comparable effort needed for the computation ofdiffraction potential and for that of radiated potential. To verify the correctness of the method, a classical example inthe reference is recomputed and the obtained results are in good accordance with those by use of other methods,which shows that the present method is correct.

General analytical method of designing shielded coils for arbitrary axial magnetic field

Magnetic coils for specific requirements are widely used in modern quantum physics. In this study, a general analytical method of designing the shielded coils for generating an arbitrary axial magnetic field is proposed. The theoretical formula for an axial magnetic field generated by a single shielded coil is obtained and used to construct specific coils. The structural parameters of these coils are determined by fitting the theoretical formula with their specific requirements. The feasibility of this method is proved by realizing four concrete kinds of coils: uniform magnetic field generating coils, gradient magnetic field generating coils, asymmetrical uniform magnetic field generating coils, and parabolic magnetic field generating coils. The correctness of these theoretical results is demonstrated by both the finite element simulations and the relevant experimental results. Furthermore, the application of this method is of great significance for developing the quantum physics and quantum devices in future.

高压大功率开关器件电磁特性的解析模型

准确获得高压大功率开关器件的电磁特性对器件所在系统的电磁干扰预测十分重要。聚焦用于高压大功率开关器件电磁特性分析的开关波形等效方法,针对当前等效波形过于理想而无法体现器件开关瞬态中复杂频谱分量的问题,提出考虑器件开关过程电磁特性的解析模型。从解析模型的时域解析式出发,基于傅里叶变换理论,推导了解析模型的频域解析式,分析频谱包络特征参数,得到了解析模型的频谱特征。利用Si IGBT和SiC MOSFET器件实测的开关波形,验证了理论分析的正确性。

基于弱信号感知的预测型供应链风险识别研究

自2020年新冠肺炎疫情以来各行业供应链运行面临着严峻的考验。疫情之下企业供应链中诸多环节都遭受了不同程度的负面影响和多种风险冲击。为保障企业供应链稳定运行,实现风险事件发生前的预警,从弱信号感知的角度出发,结合信号分析和传统供应链风险识别过程,利用AHP-FCA研究方法构建了基于弱信号感知的供应链风险评估模型。将此模型运用于某医疗器械公司,对其供应链运行过程进行评估分析,结果表明将弱信号感知引入供应链风险识别过程,能在一定程度上提高识别效率,确保供应链的稳定运行。

Recent Advances and Applications in Paper-Based Devices for Point-of-Care Testing

Point-of-care testing(POCT),as a portable and user-friendly technology,can obtain accurate test results immediately at the sampling point.Nowadays,microfluidic paper-based analysis devices(μPads)have attracted the eye of the public and accelerated the development of POCT.A variety of detection methods are combined withμPads to realize precise,rapid and sensitive POCT.This article mainly introduced the development of electrochemistry and optical detection methods onμPads for POCT and their applications on disease analysis,environmental monitoring and food control in the past 5 years.Finally,the challenges and future development prospects ofμPads for POCT were discussed.

An analytical model of the electric field distributions of buried superjunction devices

An analytical model of the electric field distributions of buried superjunction structures,based on the charge superposition method and Green＇s function approach,is derived.An accurate approximation of the exact analytical model of the vertical electric field is also proposed and demonstrated by numerical simulation.The influence of the dimension and doping concentration of each layer on the electric field is discussed in detail,and the breakdown voltage is demonstrated by simulations.

Paper-based fluorescent devices for multifunctional assays:Biomarkers detection,inhibitors screening and chiral recognition

The development of a single analytical platform with different functions is highly desirable but remains a challenge at present.Here,a paper-based device based on fluorescent carbon dots(CDs)functionalized paper/MnO_(2)nanosheets(MnO_(2)NS)hybrid devices(PCD/NS)was proposed for single-device multi-function applications.MnO_(2)NS functioned as a fluorescence quencher of CDs and recognizer of H_(2)O_(2)released from the oxidase catalyzed system.Fluorescence recovery would occur after the decomposition of MnO_(2)NS induced by H_(2)O_(2),by which a simple and effective strategy could be developed for fluorescence monitoring multiplex biological events.Xanthine(XA)sensing,xanthine oxidase(XOD)inhibitors screening analysis and chiral recognition of glucose enantiomers were performed on PCD/NS to investigate the multifunctional application of the paper-based device.By means of PCD/NS,XA could be determined in the range of 0.1–40μmol/L with a low detection of limit of 0.06μmol/L.The IC_(50)value of allopurinol,the model inhibitor of XOD,was sensitively detected to be 7.4μmol/L.Glucose enantiomers were also recognized in terms of the specific fluorescence response to d-glucose.This work firstly presented a paper-based device capable of biomarkers detection,inhibitors screening and chiral recognition,which enlightened a promising strategy for the construction of multifunctional devices and hold the great potential application in clinical diagnosis and drug discovery.

纸上微型实验室在食品检测领域的研究进展

“纸上微型实验室”是以纸为基底的微型分析系统,其因高灵敏、低成本、便携化、可批量生产等独特优势突破了传统检测技术的局限,在食品现场快速检测领域展现出巨大应用潜力。本文梳理了典型的“纸上微型实验室”,分别对纸层析法、化学试纸、侧流层析试纸条、纸基微流控分析装置和合成生物学纸进行全面综述,并重点介绍了“纸上微型实验室”在食品检测领域中的应用,最后讨论了纸基分析方法的优势、挑战和发展趋势,以期为“纸上微型实验室”更全面地应用于食品检测领域提供理论支撑。

基于模糊网络分析法的膝踝足支具舒适性评价与设计

为判定并提升膝踝足支具的使用舒适性,从用户的生理、物理和心理角度出发,结合人因试验和模糊网络分析法(Fuzzy Analytic Network Process, FANP),建立了舒适度指标和舒适感指标相结合的舒适性评价指标体系,确定了舒适度指标的评价标准,构建了膝踝足支具舒适性评价模型。以3种不同类型的膝踝足支具为例,对其进行优劣排序和评价分析,根据分析结果对其中1种进行改进,得到3种支具方案和1套服务系统,并借助眼动试验筛选出最佳造型方案。对膝踝足支具最佳方案进行舒适性评价,结果与改进前相比,其舒适性提高了39%。结果表明:该舒适性评价模型可有效评价和指导膝踝足支具的舒适性设计,为康复辅具的舒适性改善提供参考。

无人机多光谱数据可靠性分析与冬小麦产量估算研究

无人机多光谱遥感用于冬小麦产量预测中捕获的数据准确性不高,为指导田块尺度下冬小麦产量的精准预测,需构建高精度的冬小麦产量估算模型。本研究利用校正后的近地面高光谱数据(Field-Spec 3型野外光谱仪获取)验证低空无人机多光谱遥感数据(大疆精灵4型多光谱相机获取),将通过无人机多光谱影像计算的植被指数与经验统计方法结合,采用一元回归和多元线性回归分别对抽穗期、开花期和灌浆期冬小麦进行基于单一植被指数和多植被指数组合的产量估算,其中多植被指数包括归一化差异植被指数(NDVI)、优化的土壤调节植被指数(OSAVI)、绿色归一化差值植被指数(GNDVI)、叶片叶绿素指数(LCI)和归一化差异红色边缘指数(NDRE)。结果表明,基于单一植被指数的冬小麦估产模型,一元二次回归模型精度最高,而基于5种植被指数的多元线性回归模型在3个生育时期的拟合效果均优于单植被指数模型。一元或多元回归模型在抽穗期的拟合效果最好。冬小麦基于GNDVI指数的一元二次回归估产模型建模集的决定系数(R^(2))、均方根误差(RMSE)分别为0.69、428.91 kg/hm^(2),验证集的R^(2)、RMSE、相对均方根误差(RRMSE)分别为0.76、418.14 kg/hm^(2)、11.56%。基于5种植被指数组合的多元线性回归估产模型建模集的R^(2)、RMSE分别为0.80、340.14 kg/hm^(2),验证集的R^(2)、RMSE、RRMSE分别为0.69、466.75 kg/hm^(2)、12.90%。综上所述,大疆精灵4型多光谱相机捕获的数据在估算冬小麦产量方面具有广阔的应用前景;冬小麦产量估算的最适模型为基于抽穗期多植被指数组合建立的多元线性回归模型。

纸基微流控芯片原纸的构建及其对颜色信号均匀性的优化研究

为了提高纸基芯片比色检测结果的均匀性,对漂白硫酸盐松木浆进行PFI磨浆处理,制备实验室原纸。与常用于构建纸基芯片的滤纸进行对比,本研究制备的纸基底表现出良好的颜色均匀性。在Fe^(2+)比色检测中,该纸基芯片分析响应在1~75 mg/L范围内线性相关良好(R^(2)=0.9599),检测下限为0.4 mg/L,并成功实现了对实际水样中Fe^(2+)的(半)定量检测。

酶的固定化方法在微流控芯片技术中的应用

对微流控芯片上酶的固定化方法进行了综述,系统总结了酶的常见固定化方法及微流控芯片体系中酶的固定化方法,如常见的包埋法、物理吸附法、化学交联法、共价键合法等。为微流控芯片体系酶的固定化研究提供参考,对药物筛选新方法的建立指出新思路。

基于层次分析的医疗器械不良事件主动报告影响因素分析

目的:分析医院以护理人员为主体基于层次分析法(AHD)的主动上报医疗器械不良事件影响因素并提出相应改进措施。方法:选取医院2021年度上报医疗器械不良事件例数为0的22个临床科室,自制调研问卷调研临床科室护士长主导的上报主体,采用AHP分析影响医疗器械不良事件主动上报的主要因子并制定相关改进对策。结果:2021年医院共上报医疗器械不良事件99例,其中医疗设备类不良事件22例,医用耗材类不良事件77例。影响医疗器械主动上报因素的7项指标权重占比由高到低依次为产品信息不易查找(占17.317%)、故障过程等分析复杂上报流程繁琐(占17.073%)、不影响日常工作忽略上报(占15.854%)、可疑不良事件发生后无上报意识(占14.878%)、上报后担忧产生医疗纠纷(占13.902%)、不知晓上报途径或范围(占10.732%)和奖励机制不知晓或不具吸引力(占10.244%)。结论:医疗器械不良事件主动有效上报可以为医疗器械监督管理提供监管依据,减少或避免同类医疗器械不良事件重复发生;应加强医院设备管理工程师对医疗器械不良事件的日常管理,提高临床科室护士长医疗器械不良事件上报思想认识,降低患者、医务人员和其他人员使用医疗器械风险,保障临床用械安全。