Test Line Research Articles

Alteration in Biochemical Responses in Leaves of Potato due to Common Scab Disease

The current study was designed at the research area of Plant Pathology Research Institute, Ayub Agricultural Research Institute, Faisalabad, Pakistan during 2017– 2020. Fresh leaves of inoculated and un-inoculated potato varieties highly susceptible (FD 76-36), moderately susceptible (FD 73-110), and resistant (Esmee)/ test lines were collected during 2017-18 and 2018-19, at 35, 65 and 95 days after sowing for biochemical analysis. Superoxide dismutase activity, Catalase activity, Per-oxidase activity, Protein and Total phenolics contents were quantified. FD 76-36 exhibited minimum SOD activity (67.733, 45.637, 24.910) %, followed by FD 73-110 (70.303,57.893, 42.513) % and Esmee (84.567, 65.167, 45.873) % after 35, 65 and 95 days of inoculation respectively as compared to control. FD 76-36 expressed minimum CAT activity (10.990, 7.473, 3.413) %, followed by Esmee (13.537, 9.630, 8.147) % and FD 73-110 (19.277, 8.147, 6.170) % after 35, 65 and 95 days of inoculation respectively as compared to control. FD 76-36 exhibited minimum POD activity (0.2133, 0.2767, 0.3600) %, followed by FD 73-110 (0.2900, 0.5567, 0.6300) % and Esmee (0.8800, 1.2733, 1.5433) % after 35, 65 and 95 days of inoculation respectively as compared to control. FD 76-36 expressed minimum protein contents (3.097, 2.873, 1.260) %, followed by FD 73-110 (7.907, 5.423, 4.267) % and Esmee (12.163, 8.633, 5.127) % after 35, 65 and 95 days of inoculation respectively as compared to control. FD 76-36 expressed minimum TPC (136.31, 115.58, 70.77) %, followed by FD 73-110 (165.85, 136.75, 86.89) % and Esmee (188.42, 158.38, 109.00) % after 35, 65 and 95 days of inoculation respectively as compared to control. The experiment was conducted with a randomized complete block design (RCBD) and three replications. The experimental data were analyzed using Fisher’s analysis of variance technique and treatment means were compared by the least significance difference (LSD) test at a 5% probability level.

DEVELOPMENT OF BATTERY MANAGEMENT SYSTEM AND REVIEW OF CANBUS DATA TRAFFIC

Recently, the use and production of electric vehicles has been increasing. In parallel with this increase, electric vehicle technologies are constantly developing. With the increase in the use of electric vehicles, the importance of BYS (Battery Management System), which controls the charge and discharge cycles of batteries, is increasing and researches are being carried out to increase their efficiency. Batteries with high energy density used in electric vehicles need to be kept under constant control. A large number of cells are used to obtain the high voltage and capacity required by electric vehicles. Each cell needs a battery management system to keep it under control. CAN (Controller Area Network) is used in BYS communication with the vehicle. In this study, the data traffic on the CAN line of the BYS used in today's electric vehicles has been analyzed. In this analysis, instant data of the battery pack is sent over the CAN line. The system includes BYS, charger and VCU (Vehicle Control Unit). An experimental setup with BYS, VCU and charger nodes was prepared and line load calculation was made on this experimental setup. Three different methods were used in the line load calculation process and the relationship of these methods with each other was compared. Different CAN speeds were used in the test stages and line load analysis was performed by changing the message sending frequencies. According to the data obtained from the prepared experimental setup, it was seen that the load of the messages on the CAN line was between 1.97% and 19.58%.

A novel patches-selection method for the classification of point-of-care biosensing lateral flow assays with cardiac biomarkers

Cardiovascular Disease (CVD) is amongst the leading cause of death globally, which calls for rapid detection and treatment. Biosensing devices are used for the diagnosis of cardiovascular disease at the point-of-care (POC), with lateral flow assays (LFAs) being particularly useful. However, due to their low sensitivity, most LFAs have been shown to have difficulties detecting low analytic concentrations. Breakthroughs in artificial intelligence (AI) and image processing reduced this detection constraint and improved disease diagnosis. This paper presents a novel patches-selection approach for generating LFA images from the test line and control line of LFA images, analyzing the image features, and utilizing them to reliably predict and classify LFA images by deploying classification algorithms, specifically Convolutional Neural Networks (CNNs). The generated images were supplied as input data to the CNN model, a strong model for extracting crucial information from images, to classify the target images and provide risk stratification levels to medical professionals. With this approach, the classification model produced about 98% accuracy, and as per the literature review, this approach has not been investigated previously. These promising results show the proposed method may be useful for identifying a wide variety of diseases and conditions, including cardiovascular problems.

Multiline aiming at phenotypic stability and rice blast resistance

This study aimed to verify the efficiency of multilines in reducing blast progress and their potential benefits to phenotypic stability in rice. The experiments were conducted in the 2016/17 and 2017/18 agricultural years. A randomized block design was performed with three replications, evaluating 12 lines and a multiline, which consisted of five lines from the Cultivation and Use Value (CUV) test. The multiline presented an estimated grain yield above the average of experiments of around seven bags ha-1 and superior performance in early flowering, justifying the high phenotypic stability for these characters. In this case, the line selection for composing the multiline was favorable and efficient, highlighted by a higher agronomic performance than most lines of the CUV test. The multiline is an adequate strategy to provide higher phenotypic stability and reduce blast progress in the field.

Specific lateral flow detection of isothermal nucleic acid amplicons for accurate point-of-care testing

For point-of-care testing (POCT), coupling isothermal nucleic acid amplification schemes (e.g., recombinase polymerase amplification, RPA) with lateral flow assay (LFA) readout is an ideal platform, since such integration offers both high sensitivity and deployability. However, isothermal schemes typically suffers from non-specific amplification, which is difficult to be differentiated by LFA and thus results in false-positives. Here, we proposed an accurate POCT platform by specific recognition of target amplicons with peptide nucleic acid (PNA, assisted by T7 Exonuclease), which could be directly plugged into the existing RPA kits and commercial LFA test strips. With SARS-CoV-2 as the model, the proposed method (RPA-TeaPNA-LFA) efficiently eliminated the false-positives, exhibiting a lowest detection concentration of 6.7 copies/μL of RNA and 90 copies/μL of virus. Using dual-gene (orf1ab and N genes of SARS-CoV-2) as the targets, RPA-TeaPNA-LFA offered a high specificity (100%) and sensitivity (RT-PCR Ct < 31, 100%; Ct < 40, 71.4%), and is valuable for on-site screening or self-testing during isolation. In addition, the dual test lines in the test strips were successfully explored for simultaneous detection of SARS-CoV-2 and H1N1, showing great potential in response to future pathogen-based pandemics.

A simple method for the recovery of palynomorphs from rock gypsum and rock anhydrite

A method for the relatively fast, inexpensive, and safe dissolution of rock gypsum and rock anhydrite for the recovery of palynomorphs is described. Rock gypsum and rock anhydrite deposits are widely distributed geographically and throughout the geologic column. They represent deposition under environmental conditions unlike those of most other rock types. Consequently, palynomorphs and other microfossils recovered from these rocks may present unique paleontological and biostratigraphic insights not provided by other strata. Despite their relatively high solubility, rock gypsum and rock anhydrite tend to be difficult to process and do not yield to typical palynological methods. Consequently, potentially important sequences of sulfate rocks may be largely neglected in palynological investigations. The method described herein utilizes gently boiling dilute (10%) hydrochloric acid (HCl) and will completely dissolve 25 grams of rock gypsum in approximately 1.5 hours. Rock anhydrite can be similarly treated but takes substantially longer than gypsum to completely dissolve. Important aspects of the process include boiling HCl at or near 102 °C, a beaker without a pouring spout but with a loose-fitting cover to reduce evaporation, and quenching of the hot solution in cool, filtered water to prevent reprecipitation of the dissolved calcium sulfate. The size of the rock fragments treated by this process also appears to be of importance with larger pieces of gypsum but smaller pieces of anhydrite producing the best results. Palynomorphs recovered by this method show no apparent deterioration of the exines. In addition to palynomorphs (spores, pollen, dinoflagellates, etc.), the method also resulted in the recovery of other acid insoluble fossils such as foraminiferal test linings, scolecodonts, arthropod fragments and diatoms as well as amorphous inorganic material and acid insoluble minerals. The method is also safe as long as appropriate precautions are taken.

Acceleration-Guided Acoustic Signal Denoising Framework Based on Learnable Wavelet Transform Applied to Slab Track Condition Monitoring

Acoustic monitoring has recently shown great potential in the diagnosis of infrastructure condition. However, due to the severe noise interference in acoustic signals, meaningful features tend to be difficult to infer. It creates a considerable obstacle for an extensive application of acoustic monitoring. To tackle this problem, we propose an acceleration-guided acoustic signal denoising framework (AG-ASDF) based on learnable wavelet transform to automatically denoise the acoustic signal and extract the relevant features based on the acceleration signal. This denoising framework requires the acceleration signal only for the training stage. Therefore, only acoustic sensors (non-intrusive) need to be installed during the application phase, which is convenient and crucial for the condition monitoring of safety-critical infrastructure. A comparative study is conducted among the proposed AG-ASDF and other feature learning / extraction methods, by using a multi-class support vector machine to evaluate the detection effectiveness of slab track condition based on acoustic signals. Different healthy and unhealthy states of slab tracks are imitated with three types of slab track supporting conditions in a railway test line. The classification based on the proposed AG-ASDF features outperforms other feature extraction and learning methods with a significant accuracy improvement.

SOX1 antibody-related paraneoplastic neurological syndromes: clinical correlates and assessment of laboratory diagnostic techniques.

To describe the clinical associations of SOX1 antibodies (SOX1-Abs), determine the accuracy of various detection techniques, and propose laboratory criteria to identify definite paraneoplastic neurological syndromes (PNS) associated with SOX1-Abs. Single-center, retrospective study of patients referred to the French Reference Center between 2009 and 2019 for confirmation of SOX1-Ab positivity, without concurrent neural antibodies. Patients were classified according to the updated diagnostic PNS criteria; biological samples were systematically retested with three distinct techniques (line blot, cell-based assay, indirect immunofluorescence). Among 77 patients with isolated SOX1-Ab positivity, 23 (29.9%) fulfilled the criteria for definite PNS; all of them had lung cancer (mostly small-cell) and presented mainly with Lambert-Eaton myasthenic syndrome (10/23) and rapidly progressive cerebellar ataxia (6/23). SOX1-Ab positivity varied depending on the laboratory methods which were used, and a single technique was not sufficient to draw conclusions about the PNS diagnosis. The combination of an antigen-specific test (line blot and/or cell-based assay) and immunofluorescence showed the highest accuracy (81.5%, 95% CI 70.0-90.1) in identifying definite PNS. Moreover, when the PNS-Care score was recalculated assigning three points at the laboratory-level only to patients with positive "antigenic-specific test + immunofluorescence" and 0 points to the remaining cases, a higher certainty for definite and non-PNS was achieved (from 41/77, 53.2%, to 60/77, 77.9%; p < 0.001). SOX1-Abs should be considered high-risk antibodies only when detected with a positive antigenic-specific test and immunofluorescence. Other laboratory results and clinical associations different from Lambert-Eaton myasthenic syndrome and rapidly progressive cerebellar ataxia should be carefully reassessed to rule out false positivity and alternative diagnoses.

Quasi-steady imbibition of physiological liquids in paper-based microfluidic kits: Effect of shear-thinning

In the present work, spontaneous imbibition of shear-dependent fluids is numerically investigated in a two-layered, rectangular/fan-shaped, paper-based diagnostic kit using the modified Richards equation. It is shown that the average velocity at the test line of the kit is strongly influenced by the absorbent pad's microstructure with its contact angle playing a predominant role. Assuming that the test fluid is shear-thinning, a generalized version of the Richards equation, valid for power-law fluids, was used to investigate the effect of shear-thinning on the quasi-steady regime. The shear-thinning behavior of the test fluid is predicted to shorten the duration of the constant-velocity regime on the nitrocellulose membrane used as the test cell. By manipulating the contact angle and/or choosing appropriate microstructure for the absorbent pad, it is still possible to establish a constant velocity regime at the test line for nearly five minutes even for such fluids. A comparison between our numerical results and published numerical results obtained using simplistic theories has revealed the key role played by the transition, partially saturated zone near the advancing front during the liquid imbibition. The general conclusion is that use should preferably be made of robust models such as Richards equation for the design of lateral-flow, paper-based assays.

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

• We developed a novel method for pathogen detection in foods. • It combined QBs-labelled LFIAS and SD-LAMP to achieve quantitative detection. • The combined test rapidly and sensitively detected Salmonella Thyphimurium. • Current approach does not require almost any equipment allowing point-of-care use. • The efficacy of the current test was confirmed in different food samples. 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 CFU·mL −1 . The visual limit of detection was 10 3 CFU·mL −1 , indicating that the system was 10-fold more sensitive than AuNPs-labelled test strips. ST specificity was analyzed in accordance with agarose gel outputs of 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.

Evaluation of the immune colloidal gold technique for BP180-NC16A-specific antibodies in the quick diagnosis and monitoring of bullous pemphigoid

BackgroundBullous pemphigoid (BP) mostly involves elderly patients. The diagnosis of BP requires special immunological tests, which makes some patients unable to be diagnosed and treated timely. ObjectiveThe accuracy and application value of immune colloidal gold technique (ICGT) in BP were evaluated. The colloidal gold was conjugated with recombinant BP180 NC16A protein and mouse IgG antibody. As the test and control lines, the mouse-anti-human IgG and goat-anti-mouse IgG, respectively, were blotted on the nitrocellulose membrane. Methods414 serum samples of consecutive patients with suspected BP and 15 samples from healthy donors were recruited. The consistency between ICGT and ELISA, and between serum and plasma/whole blood were evaluated. Subgroup analyses were performed in terms of clinical characteristics. We also followed up 65 BP patients’ strip results to explore the predictive value of ICGT. ResultsStrong agreements between ICGT and ELISA(κ = 0.902) and between plasma/whole blood and serum samples (κ = 0.980) with good stability were observed. The ICGT achieved sensitivity of 93.9%, and specificity of 97.6%. In subgroup analysis, the sensitivity was significantly higher in older patients (96.3%), and with more typical lesions such as blisters (96.2%) and erosions (92.4%). In follow-up, we also found BP patients who kept ICGT-negative in remission state all got consecutive positive strips 1–3 weeks prior to mild new activity or flare. ConclusionICGT shows high potential as a rapid and stable option for the diagnosis and monitoring of BP. Further investigations are needed to re-evaluate this technique in a prospective study with a multicenter design.

Development of a CRISPR/Cas9-integrated lateral flow strip for rapid and accurate detection of Salmonella

Rapid and accurate detection of foodborne pathogens is crucial for safeguarding human health. Herein, we constructed a clustered regularly interspaced short palindromic repeat (CRISPR)/Cas9-integrated lateral flow strip (Cas9-LFS) for detecting Salmonella . A primer set targeting the fimA gene of Salmonella spp. was used to amplify all Salmonella serovars. After extraction, the genomic DNA of Salmonella was amplified with unlabelled forward primer and FITC-labelled reverse primer, thus producing numerous FITC-labelled amplicons that can be precisely recognized by Cas9 complexed with a specific single-guide RNA (sgRNA). When loaded on the LFS, the complexes of amplicons and Cas9/sgRNA can act as bonds to anchor gold nanoparticles to the test line, resulting in a visible color change. This design makes Cas9-LFS more powerful than conventional LFS in eliminating false-positives caused by primer dimers. By using Salmonella Typhimurium as a reference strain, Cas9-LFS achieved a limit of detection as low as 10 2 CFU/mL and showed good accuracy in distinguishing Salmonella -contaminated milk. We expect this unique strategy to open a new window for building versatile pathogen detection tools. • A CRISPR/Cas9-integrated LFS (Cas9-LFS) was constructed for accurate and visual detection of Salmonella. • Primer-dimer interference that is inevitable in conventional amplifications can be totally overcome with the method. • As low as 10 2 CFU/mL of Salmonella can be well measured with the constructed method. • Salmonella -contaminated milk samples have been measured with considerable accuracy.

Vertical Magnetic Field Distribution Characteristics of Triple-Peak Halbach Array PMG and Its Engineering Application in HTS Maglev Train

The maglev train has a broad application prospect in the field of high-speed transportation, which is based on the high-temperature superconductor permanent magnet guideway (HTS-PMG) maglev system. The optimized design of the permanent magnet guideway (PMG) configuration is of great significance to improve the overall performance of the system and reduce the cost. In this article, a triple-peak Halbach array PMG is proposed, which is suitable for the HTS-PMG maglev system based on square single-seed melt-texture YBa <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Cu <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7-</sub> <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">_x</i> block with a width of 40 mm. Through theoretical calculations, the influence of structural parameters of triple-peak Halbach array PMG on the vertical magnetic field distribution characteristics is revealed, that is, increasing the proportion of horizontally magnetized permanent magnet (vertically magnetized permanent magnet) is conducive to enhancing the vertical magnetic field in the regions close to (far away from) PMG. Furthermore, combined with the engineering application of HTS-PMG maglev train, an optimized triple-peak Halbach array PMG sample is fabricated. And the reliability of the theoretical model of triple-peak Halbach array PMG is verified by simulation and experimental measurements. Based on the optimized PMG, a full-scale HTS-PMG maglev train test line with a length of 22 m and a standard gauge of 1.435 m (in China) is built up, and the manned test is successfully carried out, which shows the feasibility of the triple-peak Halbach array PMG in large-scale engineering application of the HTS-PMG maglev train.

Characteristic Analysis of Coreless-Type Linear Synchronous Motor With the Racetrack Coils as Secondary for EDS Maglev Train

The characteristics of coreless-type linear synchronous motor, which is applied in the propulsion system of electrodynamic suspension maglev train are calculated and analyzed by the more accurate analytical model. First, the magnetomotive force distribution model of the vehicle coils is proposed according to their racetrack shape. Then, on the basis of the space harmonic method, the characteristic analysis formula of coreless-type linear synchronous motor with single-layer and double-layer armature winding are presented. Second, the air-gap flux density, back electrodynamic force, and thrust of the coreless-type linear synchronous motor are analyzed by the three-dimensional finite element simulation method and the analytical methods. Then, the relationship of efficiency, power factor, and power angle with the number of feeder units is obtained. Finally, the accuracy of the analytical model and numerical result are experimentally validated by comparing with the transient operation data on Yamanashi and Miyazaki test line.

Rapid On-Site Detection of Extensively Drug-Resistant Genes in Enterobacteriaceae via Enhanced Recombinase Polymerase Amplification and Lateral Flow Biosensor.

The widespread emergence of transferable extensively drug-resistant (XDR) genes, including blaNDM and blaKPC for carbapenem resistance, mcr-1 for colistin resistance, and tet(X4) and tet(X6) for tigecycline resistance, in Enterobacteriaceae poses a major threat to public health. Thus, rapid on-site detection of these XDR genes is urgently needed. We developed a cascade system with a unitary polyethylene glycol (PEG) 200-enhanced recombinase polymerase amplification (RPA) as the core, combined with a modified Chelex-100 lysis method and a horseradish peroxidase (HRP)-catalyzed lateral flow immunoassay (LFIA) biosensor, to accurately detect these genes in Enterobacteriaceae. The conventional Chelex-100 lysis method was modified to allow in situ extraction of bacterial DNA in 20 min without requiring bulky high-speed centrifuges. Using PEG 200 increased the amplification efficiency of the RPA by 13%, and the HRP-catalyzed LFIA biosensor intensified the colorimetric signal of the test line. Following optimization, the sensitivity of the cascade system was <10 copies/μL with satisfactory specificity, allowing for highly sensitive detection of these XDR genes in Enterobacteriaceae. The complete detection procedure can be completed in less than 1 h without using large-scale instruments. This assay is conducive to rapid on-site visual detection of these XDR genes in Enterobacteriaceae in practical applications, thus providing better technical support for clinical surveillance of these genes and better treatment of XDR pathogens. IMPORTANCE Carbapenem, colistin, and tigecycline are considered the last resorts for treating severe bacterial infections caused by extensively drug-resistant (XDR) pathogens. A major threat to public health is the emergence and prevalence of transferable XDR genes in Enterobacteriaceae, such as blaNDM and blaKPC for carbapenem resistance, mcr-1 for colistin resistance, and tet(X4) and tet(X6) for tigecycline resistance. Therefore, it is imperative to develop rapid on-site methods to detect these XDR genes. In this study, we constructed a cascade system for detecting these genes based on PEG 200-enhanced recombinase polymerase amplification combined with a modified Chelex-100 lysis method and HRP-catalyzed lateral flow immunoassay. The current method is capable of detecting the above-mentioned XDR genes in situ with satisfactory specificity and sensitivity, which could provide technical support for the surveillance of these genes and provide medication recommendations for the treatment of relevant clinical infections.

A reliable upconversion nanoparticle-based immunochromatographic assay for the highly sensitive determination of olaquindox in fish muscle and water samples

Olaquindox residues in food from its illegal use has received great attention. Here, an immunoassay strategy integrating an upconversion nanoparticle (UCNP)-based immunochromatographic strip with a fluorescence reader was proposed for the highly selective and sensitive detection of olaquindox. Polyacrylic acid-functionalized UCNPs were synthesized using a simple ligand exchange process and combined with an olaquindox polyclonal antibody to form a fluorescent probe. This approach achieved a sensitive response and specific recognition of olaquindox. A convenient upconversion fluorescence reader was introduced to implement accurate and sensitive quantitative analysis of olaquindox based on the fluorescence intensity of control and test lines on a strip. Under optimal conditions, the method demonstrated a favorable linear range (0–50 ng/mL) and sensitive detection (1.42 ng/mL, S/N = 3). This method was applied successfully to determine olaquindox in fish muscle and water samples, and results were consistent with an HPLC approach, and considered a promising strategy for monitoring olaquindox residuals.

A novel dual-flux immunochromatographic test strip based on luminescence resonance energy transfer for simultaneous detection of ochratoxin A and deoxynivalenol.

Mycotoxins are secondary metabolites of fungi, which seriously threaten human health. Among them, ochratoxin A (OTA) and deoxynivalenol (DON) have become the main factors that pollute cereals and by-products. In order to achieve simultaneous detection of OTA and DON quantitatively, a novel dual-flux immunochromatographic assay (dICA) was established. The dual-flux assay is based on upconversion nanoparticles (UCNPs) as fluorescence tags to label antigens and gold nanoparticles (AuNPs) as fluorescence quencher to label monoclonal antibodies (mAbs). The intensity of the green fluorescence (540nm) of UCNPs can be used as an analytical signal, indicating the formation of antigen-antibody immune complexes, thereby indicating the presence or absence of the target analyte. Theintensity of the red fluorescence (660nm) of UCNPs is not affected and can be used as a quality control signal, and the dual-flux bidirectional single-line labeling mode allows for the simultaneous detection of two different mycotoxins on two test lines. This work indicated that the developed dICA provided a sensitive, rapid, and reliable on-site simultaneous detection of multiple mycotoxins.

Characterization by image analysis of the dose vs response curve for a qualitative serum hCG lateral flow immunoassay

BackgroundAs an adjunct to verification of performance characteristics of a qualitative serum hCG lateral flow immunoassay (LFI), we performed image analysis to characterize the dose vs response curve (visibility of the test line), as a means of understanding the transition from negative to positive as a function of increasing [hCG]. MethodsUsing serum samples of known [hCG], device images were obtained using a scanner at the prescribed reading time (5 min). Image analysis (using Python and R) was used to obtain the integral (S) of the test-line color as a function of [hCG]. ResultsData for S as a function of [hCG] were well characterized by a simple hyperbola: S = Smax [hCG]/([hCG] + K), where K = 202 mIU/ml (r = 0.997). Replicates of S at K had CV of 7.3 %. By eye, uncertainty of test results among users occurred only below the assay's stated sensitivity of 10 mIU/ml, in region of S < 3 % of Smax, and signal:noise ratio < 3. ConclusionsBy image analysis, the dose vs response (Test line integral) for this qualitative serum hCG LFI was a simple hyperbola. Characterization of the dose vs response curve was useful in verification of the assay's performance characteristics.

Source-rock potential and paleoenvironment of the Coniacian Numanha Formation, northeastern Nigeria: An integrated palynofacies and geochemical approach

A study of source-rock characterization and paleoenvironmental interpretation has been carried out on a relatively thick Coniacian sedimentary succession from the Numanha Formation in the Guyuk area of the Yola arm in the Northern Benue Trough, northeastern Nigeria. The aim is to provide organic facies data for the assessment of its hydrocarbon generating potential owing to the high prospects of its lateral equivalent Fika Shale in the Gongola arm of the Northern Benue Trough. The investigation of 98 samples from three outcrop sections [09° 50′ N, 11° 51′ E; 09° 54′ N, 11° 50′ E; 09° 54′ N, 11° 49′ E] which includes palynofacies analysis, spore/pollen coloration, and geochemical analyses enabled an evaluation of organic matter richness and quality. Measured TOC ranges between 0.01 and 7.4% which reflects poor to good organic richness, while visual kerogen characterization shows thermally mature Type II-III kerogen indicative of oil and gas prone materials. Recovered palynomorphs comprised both marine (dinoflagellate cysts, microforaminiferal test linings) and terrestrial (spores, pollen, freshwater alga Pediastrum) taxa. These palynomorphs vary in proportion at different horizons of the sections indicating shoreline fluctuations. Except for the Kurnyi section, amorphous organic matter occurs in minor percentages, indicating low preservation potential during deposition. All data indicate that the Numanha Formation was deposited in a highly proximal to mud-dominated oxic shelf environment.

The Simultaneous Determination of Chlorpyrifos-Ethyl and -Methyl with a New Format of Fluorescence-Based Immunochromatographic Assay.

The improper and excessive use in agriculture of chlorpyrifos-methyl (CPSM) and chlorpyrifos-ethyl (CPSE) may affect the health of human beings. Herein, a fluorescence-based immunochromatographic assay (FICA) was developed for the simultaneous determination of CPSM and CPSE. A monoclonal antibody (mAb) with equal recognition of CPSM and CPSE was generated by the careful designing of haptens and screening of hybridoma cells. Instead of labeling fluorescence with mAb, the probe was labeled with goat-anti-mouse IgG (GAM-IgG) and pre-incubated with mAb in the sample. The complex could compete with CPS by coating antigen in the test line. The new format of FICA used goat-anti-rabbit IgG (GAR-IgG) conjugated with rabbit IgG labeled with fluorescence microspheres as an independent quality control line (C line). The novel strategy significantly reduced nonspecific reactions and increased assay sensitivity. Under the optimal conditions, the proposed FICA showed a linear range of 0.015-64 mg/L and limit of detection (LOD) of 0.015 mg/L for both CPSE and CPSM. The average recoveries of CPS from spiked food samples by FICA were 82.0-110.0%. The accuracy was similar to the gas chromatography-tandem mass spectrometry (GC-MS/MS) results. The developed FICA was an ideal on-site tool for rapid screening of CPS residues in foods.