On-site rapid detection of multiple pesticide residues in tea leaves by lateral flow immunoassay

The application of pesticides (mostly insecticides and fungicides) during the tea-planting process will undoubtedly increase the dietary risk associated with drinking tea. Thus, it is necessary to ascertain whether pesticide residues in tea products exceed the maximum residue limits. However, the complex matrices present in tea samples comprise a major challenge in the analytical detection of pesticide residues. In this study, nine types of lateral flow immunochromatographic strips (LFICSs) were developed to detect the pesticides of interest (fenpropathrin, chlorpyrifos, imidacloprid, thiamethoxam, acetamiprid, carbendazim, chlorothalonil, pyraclostrobin, and iprodione). To reduce the interference of tea substrates on the assay sensitivity, the pretreatment conditions for tea samples, including the extraction solvent, extraction time, and purification agent, were optimized for the simultaneous detection of these pesticides. The entire testing procedure (including pretreatment and detection) could be completed within 30 min. The detected results of authentic tea samples were confirmed by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), which suggest that the LFICS coupled with sample rapid pretreatment can be used for on-site rapid screening of the target pesticide in tea products prior to their market release.

采用Allergy Lateral Flow Assay检测过敏原特异性IgE抗体的性能评价

目的Allergy Lateral Flow Assay(ALFA)是一种便捷、小巧的过敏原检测新技术,本研究以荧光酶联免疫全定量ImmunoCAP法为“金标准”,旨在探讨ALFA的检验效能及在中国南方地区的应用价值。方法利用ALFA技术与ImmunoCAP技术检测100例过敏性疾病患者血清屋尘螨、粉尘螨、热带无爪螨、猫毛皮屑、狗毛皮屑、蟑螂和艾蒿sIgE水平。结果以ImmunoCAP法为“金标准”,结果显示,ALFA检测粉尘螨的一致性最高(κ=0.56,P<0.05),其次是屋尘螨(κ=0.43,P<0.05);同时,ALFA检测粉尘螨(87.6%)、猫毛皮屑(73.7%)和屋尘螨(87.6%)的总一致率均较高。经受试者工作特征曲线分析显示,ALFA诊断螨类过敏原的曲线下面积均大于0.90(P<0.05)。对于屋尘螨、粉尘螨和猫毛皮屑过敏原,ALFA与ImmunoCAP系统的sIgE检测结果具有强相关性(r I>0.8,P<0.05)。结论ALFA具有良好的诊断效能,可满足临床检测要求,因其无须昂贵的检测仪器和检测费用,可为基层医院临床筛查应用提供新的选择。

Hierarchical Nanogold Labels to Improve the Sensitivity of Lateral Flow Immunoassay

Lateral flow immunoassay(LFIA) is a widely used express method and offers advantages such as a short analysis time, simplicity of testing and result evaluation.However, an LFIA based on gold nanospheres lacks the desired sensitivity, thereby limiting its wide applications.In this study, spherical nanogold labels along with new types of nanogold labels such as gold nanopopcorns and nanostars were prepared, characterized, and applied for LFIA of model protein antigen procalcitonin. It was found that the label with a structure close to spherical provided more uniform distribution of specific antibodies on its surface, indicative of its suitability for this type of analysis.LFIA using gold nanopopcorns as a label allowed procalcitonin detection over a linear range of 0.5–10 ng mL^(-1) with the limit of detection of 0.1 ng mL^(-1), which was fivefold higher than the sensitivity of the assay with gold nanospheres. Another approach to improve the sensitivity of the assay included the silver enhancement method,which was used to compare the amplification of LFIA for procalcitonin detection. The sensitivity of procalcitonin determination by this method was 10 times better the sensitivity of the conventional LFIA with gold nanosphere as a label. The proposed approach of LFIA based on gold nanopopcorns improved the detection sensitivity without additional steps and prevented the increased consumption of specific reagents(antibodies).

Study of Turbulent Flow of Film Cooling Holes with Lateral Expanded Exits

Hot wire measurements and flow visualization are presented for studying the turbulent flow field over a flat gas turbine film cooling blade with lateral expanded holes. Three mass flux ratios of jet to free stream, M = 0.5, 0.89, 1.5, are tested. The streamwise velocity, the turbulent intensities and the Reynolds shear stress are measured. The effect of the lateral expanded holes on the improvement of the turbulent flow field for film cooling of gas turbines can be analyzed from the measured spatial di...

Lateral Shear Layer and Its Velocity Distribution of Flow in Rectangular Open Channels

The lateral velocity distribution of flow in the shear layer of open channel is required to many problems in river and eco-environment engineering, e.g. distribution of pollutant dispersion, sediment transport and bank erosion, and aquatic habitat. It is not well understood about how the velocity varies laterally in the wall boundary layer. This paper gives an analytical solution of lateral velocity distribution in a rectangular open channel based on the depth-averaged momentum equation proposed by Shiono & Knight. The obtained lateral velocity distributions in the wall shear layer are related to the two hydraulic parameters of lateral eddy viscosity (λ) and depth-averaged secondary flow (Γ) for given roughened channels. Preliminary relationships between the above two parameters and the aspect ratio of channel, B/H, are obtained from two sets of experimental data. The lateral width (δ) of the shear layer was investigated and found to relate to the λ and the bed friction factor (f), as described by Equation (26). This study indicates that the lateral shear layer near the wall can be very wide (δ/H = 14.6) for the extreme case (λ = 0.6 and f = 0.01).

Experimental and numerical study of the effect of pulsatile flow on wall displacement oscillation in a flexible lateral aneurysm model

This study experimentally and numerically investigated the effect of pulsatile flow of different frequencies and outflow resistance on wall deformation in a lateral aneurysm.A method for constructing a flexible aneurysm model was developed,and a self-designed piston pump was used to provide the pulsatile flow conditions.A fluid-structure interaction simulation was applied for comparison with and analysis of experimental findings.The maximum wall displacement oscillation increased as the pulsation frequency and outflow resistance increased,especially at the aneurysm dome.There is an obvious circular motion of the vortex center accompanying the periodic inflow fluctuation,and the pressure at the aneurysm dome at peak flow increased as the pulsatile flow frequency and terminal flow resistance increased.These results could explain why abnormal blood flow with high frequency and high outflow resistance is one of the risk factors for aneurysm rupture.

Lateral Flow Immunoassay for Quantitative Detection of Ractopamine in Swine Urine

A strip reader based lateral flow immunoassay （LFIA） was established for the rapid and quantitative detection of ractopamine （RAC） in swine urine. The ratio of the optical densities （ODs） of the test line （AT） to that of the control line （Ac） was used to effectively minimize interference among strips and sample variations. The linear range for the quantitative detection of RAC was 0.2 ng/mL to 3.5 ng/mL with a median inhibitory concentration （IC50） of 0.59＋0.06 ng/mL. The limit of detection （LOD） of the LFIA was 0.13 ng/mL. The intra-assay recovery rates were 92.97%, 97.25%, and 107.41%, whereas the inter-assay rates were 80.07%, 108.17%, and 93.7%, respectively.

Development of a Recombinase-aided Amplification Combined With Lateral Flow Dipstick Assay for the Rapid Detection of the African Swine Fever Virus

Objective To establish a sensitive,simple and rapid detection method for African swine fever virus(ASFV)B646L gene.Methods A recombinase-aided amplification-lateral flow dipstick(RAA-LFD)assay was developed in this study.Recombinase-aided amplification(RAA)is used to amplify template DNA,and lateral flow dipstick(LFD)is used to interpret the results after the amplification is completed.The lower limits of detection and specificity of the RAA assay were verified using recombinant plasmid and pathogenic nucleic acid.In addition,30 clinical samples were tested to evaluate the performance of the RAA assay.Results The RAA-LFD assay was completed within 15 min at 37°C,including 10 min for nucleic acid amplification and 5 minutes for LFD reading results.The detection limit of this assay was found to be 200 copies per reaction.And there was no cross-reactivity with other swine viruses.Conclusion A highly sensitive,specific,and simple RAA-LFD method was developed for the rapid detection of the ASFV.

Rapid and easy determination of morphine in chafing dish condiments with colloidal gold labeling based lateral flow strips

In order to enhance the flavor of chafing dish and increase the attraction of consumers,the poppy shell is reported to be illegally added to the condiments of chafing dish.In this research,a rapid,simple,and convenient method based on the classic immunochromatographic lateral flow strip(LFS)with gold nanoparticles(GNPs)labeling was developed for easy monitoring of morphine(MOP),an effective component of poppy shell.Under optimized conditions,this developed LFS can well realize the detection of target MOP in the condiments of chafing dish in less than 10 min without any complicated pre-treatments.The limit of detection(LOD)can be achieved as low as 0.1 ppb for standard MOP or the MOP spiked condiments of chafing dish.All these results of the research strongly demonstrate that this established LFS method can be successfully applied in practical rapid and accurate on-site screening of poppy shell in condiments of chafing dish.

Quantum Dot Nanobeads-Labelled Lateral Flow Immunoassay Strip for Rapid and Sensitive Detection of Salmonella Typhimurium Based on Strand Displacement Loop-Mediated Isothermal Amplification

Rapid,sensitive,point-of-care detection of pathogenic bacteria is important for food safety.In this study,we developed a novel quantum dot nanobeads-labelled lateral flow immunoassay strip(QBs-labelled LFIAS)combined with strand displacement loop-mediated isothermal amplification(SD-LAMP)for quantitative Salmonella Typhimurium(ST)detection.Quantum dot nanobeads(QBs)served as fluorescence reporters,providing good detection efficiency.The customizable strand displacement(SD)probe was used in LAMP to improve the specificity of the method and prevent by-product capture.Detection was based on a sandwich immunoassay.A fluorescence strip reader measured the fluorescence intensity(FI)of the test(T)line and control(C)line.The linear detection range of the strip was 10^(2)–10^(8) colony forming units(CFU)·mL^(-1).The visual limit of detection was 10^(3) CFU·mL^(-1),indicating that the system was ten-fold more sensitive than AuNPs-labelled test strips.ST specificity was analyzed in accordance with agarose gel outputs of polymerase chain reaction(PCR)and SD-LAMP.We detected ST in foods with an acceptable recovery of 85%–110%.The method is rapid,simple,almost equipment-free,and suitable for bacterial detection in foods and for clinical diagnosis.

Performance of simultaneous nitrification and denitrification in lateral flow biological aerated filter

A new wastewater treatment facility—lateral flow biological aerated filter (LBAF) was developed aiming at solving energy consumption and operational problems in wastewater treatment facilities in small towns. It has the function of nitrification and removing organic substrate. In this study, we focused on the denitrification performance of LBAF and its possible mechanism under thorough aeration. We identified the existence of simultaneous nitrification and denitrification (SND) by analyzing nitrogenous compounds along the flow path of LBAF and supportive microbial microscopy, and studied the effects of air/water ratio and hydraulic loading on the performance of nitrogen removal and on SND in LBAF to find out the optimal operation condition. It is found that for saving operation cost, aeration can be reduced to some degree that allows desirable removal efficiency of pollutants, and the optimal air/water ratio is 10:1. Hydraulic loading less than 0.43 m h?1 hardly affects the nitrification and denitrification performance; whereas higher hydraulic loading is unfavorable to both nitrification and denitrification, far more unfavorable to denitrification than to nitrification.

Development of Lateral-flow Immunoassay for WSSV with Polyclonal Antibodies Raised against Recombinant VP (19+28) Fusion Protein

我们为 WSSV 开发了敏感、快速的侧面流动的免疫分析(LFIA ) ，用象指示物的胶体的黄金。熔化蛋白质， VP (19+28 ) ，在 E 被表示。coli，净化并且过去常准备 polyclonal 抗体。净化的 anti-VP (19+28 ) IgG 与胶体的黄金被结合。Unconjugated anti-VP (19+28 ) IgG 和山羊反兔子 IgG 在硝化纤维素膜上被使不能调动。在汇编以后，虾样品的三个组(在每个组的 5 个单个动物) 被测试它包括了健康、垂死、死了的虾。为每个组，三不同纸巾(身体蜜汁，鳃和 hepatopancreas ) 同时被测试。在平行，所有样品也为比较用 PCR 被分析。从测试的 45 件样品，当 15 作为否定被分类时， 30 作为积极被检测。LFIA 的结果相关，那些由 PCR 分析获得了，显示这二个察觉方法有在在这初步的研究测试的样品的有限数字的一样的功效。关键词侧面流动的免疫分析 - 白点症候群病毒(WSSV )- VP19 - VP28 CLC 数字 S945.

Rapid one-step enzyme immunoassay and lateral flow immunochromatographic assay for colistin in animal feed and food

Background:Colistin(polymyxin E)is a kind of peptide antibiotic which has been approved in animal production for the purposes of disease prevention,treatment,and growth promotion.However,the wide use of colistin in animal feed may accelerate the spread of colistin-resistance gene MCR-1 from animal production to human beings,and its residue in animal-origin food may also pose serious health hazards to humans.Thus,it is necessary to develop corresponding analytical methods to monitor the addition of colistin in animal feed and the colistin residue in animal-origin food.Results:A one-step enzyme-linked immunosorbent assay(ELISA)and a lateral flow immunochromatographic assay(LFIA)for colistin were developed based on a newly developed monoclonal antibody.The ELISA showed a 50%inhibition value(IC50)of 9.7 ng/m L with assay time less than 60 min,while the LFIA had a strip reader-based detection limit of 0.87 ng/m L in phosphate buffer with assay time less than 15 min.For reducing the non-specific adsorption of colistin onto sample vial,the components of sample extraction solution were optimized and proved to greatly improve the assay accuracy.The spiked recovery experiment showed that the recoveries of colistin from feed,milk and meat samples were in the range of 77.83%to 113.38%with coefficient of variations less than 13%by ELISA analysis and less than 18%by LFIA analysis,respectively.Furthermore,actual sample analysis indicated that the two immunoassays can produce results consistent with instrumental analysis.Conclusions:The developed assays can be used for rapid qualitative or quantitative detection of colistin in animal feed and food.

Numerical Study on Characteristics of Supercavitating Flow Around the Variable-Lateral-Force Cavitator

A control scheme named the variable-lateral-force cavitator, which is focused on the control of lift force, drag force and lateral forces for underwater supercavity vehicles was proposed, and the supercavitating flow around the cavitator was investigated numerically using the mixture multiphase flow model. It is verified that the forces of pitching, yawing, drag and lift, as well as the supercavity size of the underwater vehicle can be effectively regulated through the movements of the control element of the variable-lateral-force cavitator in the radial and circumferential directions. In addition, if the control element on either side protrudes to a height of 5% of the diameter of the front cavitator, an amount of forces of pitching and yawing equivalent to 30% of the drag force will be produced, and the supercavity section appears concave inwards simultaneously. It is also found that both the drag force and lift force of the variable-lateral-force cavitator decline as the angle of attack increases.

Development of an accurate lateral flow immunoassay for PEDV detection in swine fecal samples with a filter pad design

Porcine epidemic diarrhea virus(PEDV),as the main causative pathogen of viral diarrhea in pigs,has been reported to result in high morbidity and mortality in neonatal piglets and cause significant economic losses to the swine industry.Rapid diagnosis methods are essential for preventing outbreaks and transmission of this disease.In this study,a paper-based lateral flow immunoassay for the rapid diagnosis of PEDV in swine fecal samples was developed using stable color-rich latex beads as the label.Under optimal conditions,the newly developed latex bead-based lateral flow immunoassay(LBs-LFIA)attained a limit of detection(LOD)as low as 10^(3.60) TCID_(50)/mL and no cross-reactivity with other related swine viruses.To solve swine feces impurity interference,by adding a filtration unit design of LFIA without an additional pretreatment procedure,the LBs-LFIA gave good agreement(92.59%)with RT-PCR results in the analysis of clinical swine fecal samples{n=108),which was more accurate than previously reported colloidal gold LFIA(74.07%)and fluorescent LFIA(86.67%).Moreover,LBs-LFIA showed sufficient accuracy(coefficient of variance[CV]<15%)and stable(room temperature storage life>56 days)performance for PEDV detection,which is promising for on-site analysis and user-driven testing in pig production system.

Effect of drip irrigation circuits design and lateral line length on: II-flow velocity and velocity head

The objectives of the work were to study the effect of drip irrigation circuits (DIC) and lateral lines lengths (LLL) on: Flow velocity (FV) and velocity head (VH). Laboratory tests were conducted at Irrigation Devices and Equipments Tests Laboratory, Agricultural Engineering Research Institute, Agriculture Research Center, Giza, Egypt. The experimental design of laboratory experiments was split in randomized complete block design with three replicates. Laboratory tests carried out on three irrigation lateral lines 40, 60, 80 m (LLL1, LLL2;LLL3) under the following three drip irrigation circuits (DIC): a) one manifold for lateral lines or closed circuits with one manifold of drip irrigation system (CM1DIS);b) closed circuits with two manifolds for lateral lines (CM2DIS), and c) traditional drip irrigation system (TDIS) as a control. Concerning FV values, DIC and LLL treatments could state in the following ascending orders: TDIS 1DIS 2DIS and LLL1 2 3, respectively. FV varied from 0.593 m·sec–1 to 1.376 m?sec–1. i.e FV –1 and this is necessary to avoid the effect of water hammer in the main and sub-main lines, but in lateral line, it can cause silt and clay precipitation problems. The differences in FV among DIC and LLL were significant at the 1% level. The effect of interaction: DIC X LLL on FV values, were significant at the 1% level. The maximum and minimum values of FV were noticed in these interactions: CM2DIS X LLL3 and TDIS X LLL1, respectively. The following ascending orders TDIS 1DIS 2DIS and LLL1 2 3 expressed their effects on VH respectively. Differences in VH among DIC and/or LLL were significant at the 1% with few exceptions. The effects of interactions: DIC X LLL on VH were significant at the 1% level in some cases. The maximum and minimum values of VH were found in the interactions: CM2DIS X LLL3 and TDIS X LLL1, respectively.

Determination of <i>Salmonella pullorum</i>with Nanoparticles Immune Based Lateral Flow Strip Assay

The isolation and culture of conventional detection method of salmonella can not meet the testing requirements of quick and easy detection at the grassroots level. In this study, we prepare the fluorescent nanoparticles as a marker, covalently conjugate with monoclonal antibodies of Salmonella pullorum. The whole Salmonella pullorum antigen and goat anti-mouse antibody sprayed on the nitrocellulose membranes are used as test line and control line. The fluorescence nanoparticles immune based lateral flow strips are made according to the principle of antigen-antibody immune response. The test strips may interpret results within 30 min. The results of the salmonella A, S. agona, S. chester and S. arechavaleta are positive, including, S. agona for weakly positive. After analysis, it is found that in addition to the salmonella of group A, the other positive salmonella are in group B. But it is negative of S. derby, S. rissen, and other 6 kinds of salmonella, with good specificity. The fluorescence nanoparticles immune based lateral flow strips are a little of sample can be detected fast, easily, inexpensive, easy to universal without professional technical personnel detection method. It provides a new detection method for the detections of Salmonella pullorum.

Hydrodynamic behaviour of the lateral flow biological aerated filter

Pulsed signal experiment was carried out to determine the hydrodynamic behaviours of lateral flow biological aerated filter(LBAF). With the analysis of experimental results, LBAF is viewed as an approximate plug flow reactor, and hydraulic retention time distribution function was derived based on LBAF. The results show that flow rate and aeration strength are two critical factors which influence flow patterns in LBAF reactor. The hydrodynamic behaviour analysis of LBAF is the theoretical basis of future research on improving capacity factor and developing kinetic model for the reactor.

Performances of lateral flow biological aerated filter in treating domestic wastewater

A new biological aerated filter?lateral flow biological aerated filter(LBAF) is developed. The effects of air/water ratio, hydraulic loading and the length of LBAF on pollutants removal efficiency are tested. The results show that under optimal technological conditions when hydraulic loading is 0.43 m3 m?2 h?1 and air/water ratio is 10:1, the average removal efficiencies of COD, SS, NH3-N, and TN reach 88.01%, 95.18%, 78.97% and 52.58%, respectively. An LBAF has a large pollutants handling capacity; is less liable to be blocked, and has a longer operation cycle in comparison with a traditional BAF.

Performance of alpha-defensin lateral flow test after synovial fluid centrifugation for diagnosis of periprosthetic knee infection

BACKGROUND The quantitative alpha-defensin enzyme-linked immunosorbent assay(ELISA)demands a prior synovial fluid centrifugation,whereas this processing is not routinely required prior to the alpha-defensin lateral flow test.AIM To evaluate whether a prior synovial fluid centrifugation could lead the lateral flow performance to achieve comparable results to ELISA during periprosthetic joint infection(PJI)diagnosis.METHODS Fifty-three cases were included in this study:22 classified as PJI and 31 classified as aseptic cases,according to Musculoskeletal Infection Society 2013 criteria.Synovial fluid samples were submitted to centrifugation,and the supernatant was evaluated by ELISA and lateral flow tests.The sensitivity(SE),specificity(SP)and accuracy of each method were calculated as well as the agreement between those two methods.RESULTS In all of the 31 samples from aseptic patients,alpha-defensin ELISA and lateral flow tests showed negative results for infection.Regarding the 22 infected patients,the lateral flow test was positive in 19 cases(86.4%)and the ELISA was positive in 21(95.5%).Sensibility,SP and accuracy were,respectively,86.4%(95%CI:65.1%-97.1%),100%(95%CI:88.8%-100%)and 93.2%(95%CI:82.8%-98.3%)for the lateral flow test and 95.5%(95%CI:77.2%-99.9%),100%(95%CI:88.8%-100%)and 98.1%(95%CI:89.9%-100%)for ELISA.An agreement of 96.2%between those methods were observed.No statistical difference was found between them(P=0.48).CONCLUSION Alpha-defensin lateral flow test showed high SE,SP and accuracy after a prior synovial fluid centrifugation,achieving comparable results to ELISA.Considering the lower complexity of the lateral flow and its equivalent performance obtained in this condition,a prior centrifugation might be added as a valuable step to enhance the PJI diagnosis.