Notes

[Surveillance of Culex mosquitoes in Jiangsu State coming from 2018 to 2019].
74% and 100.0%, respectively. The approach demonstrated in the study presented a good analytical performance with higher sensitivity, accuracy for consistency evaluation of TCM.A highly sensitive cationic polyfluorinated azobenzene/reduced graphene oxide (C3F7-azo+/RGO) nanocomposite electrochemical sensor for simultaneous detection of dopamine (DA), ascorbic acid (AA) and uric acid (UA) was successfully synthesized using a facile exfoliation/restacking method. The nanocomposite is self-assembled from oppositely charged graphene oxide nanosheets (GO) and polyfluorinated azobenzene cations (C3F7-azo+), and then obtained by electrochemical reduction. The structure and electrochemical properties were characterized by X-ray diffraction (XRD), energy dispersive spectrometer analysis (EDS), transmission electron microscope (TEM) and scanning electron microscope (SEM). The electrochemical property of C3F7-azo+/RGO was characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and differential pulse voltammetry (DPV). It can be clearly seen from experimental results that C3F7-azo+/RGO-modified electrode (C3F7-azo+/RGO/GCE) can detect DA, AA and UA simultaneously, and has good stability and anti-interference performance. The detection limits are 65 nM, 8 nM and 11 nM for DA, AA and UA in the ranges 57.28-134.28 μM, 0.04-6.01 μM, 9.23-23.45 μM, respectively.Exhaled breath condensate (EBC) is an attractive, non-invasive sample for clinical diagnostics. During EBC collection, its composition is influenced by the collection temperature, a factor that is often not thoroughly monitored and controlled. In this study, we assembled a novel, simple, portable, and inexpensive device for EBC collection, able to maintain a stable temperature at any value between -7 °C and +12 °C. The temperature was controlled using a microcontroller and a thermoelectric cooler that was employed to cool the aluminum block holding the glass tube or the polypropylene syringe. The performance of the novel sampler was compared with the passively cooled RTube™ and a simple EBC sampler, in which the temperature was steadily increasing during sampling. The developed sampler was able to maintain a stable temperature within ±1 °C. To investigate the influence of different sampling temperatures (i.e., +12, -7, -80 °C) on the analyte content in EBC, inorganic ions and organic acids were analyzed by capillary electrophoresis with a capacitively coupled contactless conductivity detector. It was shown that the concentration of metabolites decreased significantly with decreasing temperature. The portability and the ability to keep a stable temperature during EBC sampling makes the developed sampler suitable for point-of-care diagnostics.This work presents an all-in-one origami paper-based electrochemical platform for simple and inexpensive l-cysteine (Cys) detection using Cys as a monomer for modifying electrode surfaces. The proposed method combines the steps of electropolymerization and detection into a single device to offer a highly convenient method for the end-user. In comparison, the sensitivity toward Cys detection is a significantly increased using this modified electrode. The developed device provided a linear concentration range of 10-800 μM with a limit of detection of 5.5 μM. For application, the device was successfully applied to detect Cys in different food products such as wheat flour, bread, and cake with satisfactory results, yielding excellent intra-day and inter-day relative standard deviations (1.5-4.9%) and recoveries (84.2-110.8%). This discovery is important from the viewpoint of the development of Cys detection in other applications in the future.Here we show that the fluorescence of fluorescein isothiocyanate (FITC) is not altered by its reaction with primary amines. However, the fluorescence is rapidly quenched upon reaction with small molecular weight thiols including cysteine, glutathione, homocysteine, dithiothreitol, and sulfide. We have taken advantage of the thiol-dependent quenching of FITC to devise a sulfide specific assay by utilizing polydimethylsiloxane (PDMS) membranes that are permeable to hydrogen sulfide but not to larger charged thiols. In addition, we have discovered that the fluorescein dithiocarbamate (FDTC) formed by the reaction with sulfide can specifically react with S-nitrosothiols (RSNO) to regenerate FITC, thus serving as a specific, fluorogenic reagent to detect picomol levels of RSNO. FDTC was tested as an intracellular RSNO-sensor in germinating tomato seedlings (Solanum lycopersicum) via epifluorescence microscopy. Control plant roots exposed to FDTC showed low intracellular fluorescence which increased ∼3-fold upon exposure to extracellular S-nitrosoglutathione and ∼4-fold in the presence of N6022, a S-nitrosoglutathione reductase (GSNOR) inhibitor, demonstrating that FDTC can be used to visualize intracellular RSNO levels.The development of a semi-automated and rapid analytical technique for dermatological analysis has become a key aim of many medical and commercial entities through greater awareness of people to skin health and its importance in the 21st century. We present a proof-of-concept methodology demonstrating the use of validated non-destructive, in-situ (Nuclear Magnetic Resonance Spectroscopy) NMR techniques for characterisation and quantitation of (Natural Moisturising Factor) NMF compounds and actives from topical formulations. This quantitation is crucial for appropriate diagnosis of atopic dermatitis severity due to its association with reduced NMF abundance. This study is the first to combine diffusion NMR, semi-automated quantitation and ex-vivo skin samples to measure NMF and permeation of actives. We have shown that diffusion NMR allows for resolution between formulation components through determination of self-diffusion coefficients. We also demonstrate how the metabolomics software chenomxtm can be used to identify and quantitate individual NMF components. We show comparable results to previous literature on NMF layers in the skin, alongside reinforcing findings on permeation enhancers and heat effects on transdermal delivery of actives and formulation components. The presented methodology has shown great potential as an effective non-destructive, fast and versatile technique for dermatological analysis of physiology and actives, with future hardware and software developments in NMR making the future of dermatological analysis via NMR very promising.Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) has been widely applied in the analysis of phospholipids in biological samples. However, it remains a challenge to improve the sensitivity and reproducibility and to control the background noise of matrices. In this study, black phosphorus nanomaterial was used as the matrix of MALDI-MS, and microchannel technique was combined. This microchannel-integrated black phosphorus-assisted laser desorption/ionization (BPALDI) MS approach can effectively detect a variety of lipids with a small amount of sample, and has high sensitivity for phosphatidylcholines (PC) and lysophosphatidylcholines (LPC) with a detection limit of 0.2 μg/mL. Compared with traditional matrices, BPALDI-MS has the advantages of high sensitivity, good reproducibility, and high salt tolerance. TRC051384 This method was successfully applied in the detection of serum PC/LPC ratios in children patients with asthma or bronchopneumonia. This work provides a novel application of black phosphorus matrix and microchannel technique, and gives new insights into method development of rapid screening and identification of disease indicators in biological fluids.Nucleic acid extraction and purification before amplification is considered an essential step for nucleic acid amplification testing. However, this may cause losses or introduce errors that can lead to inaccurate results, especially when using samples with a small nucleic acid concentration. Here, we developed a direct digital chip that enabled us to detect nucleic acid without DNA extraction and purification. We have developed a self-priming liquid-dispensing digital PCR chip that does not require any external power. This is a robust anti-evaporation digital PCR chip with fast sampling and accurate quantification performance. Using this chip, we have established an on-chip direct nucleic acid amplification method that does not require nucleic acid extraction and purification for liquid biopsy samples. In order to verify the feasibility of this chip for clinical samples, we detected the EGFR T790M mutation from plasma. Results showed that EGFR T790M mutation could be detected with an accuracy of 100% and a sensitivity of 0.01%. Without nucleic acid extraction and purification, the assay avoids complex pre-processing, thus saving time and achieving precise quantification. We expect our direct digital PCR chip to have practical applications in diagnosis, screening, and research, especially in resource-deprived regions.A current nourishment issue is the development of smart and reliable analytical strategies to control in a simple way main bioactive compounds of nutritional supplements whose increasing use is deemed a trend nowadays. With this aim a quick and highly sensitive plasmonic sensor using simple citrate coated gold nanoparticles (AuNPs) as optical probe, was developed for both qualitative and quantitative global assessment of all the proteinogenic amino acids in nutritional supplements. AuNPs of five different sizes (from 19 to 74 nm) were synthesized, characterized and evaluated as optimal transductor element for the sensing approach. Critical physic-chemical conditions controlling aggregation (pH, incubation time, AuNPs amount and ionic strength) were investigated on the main five types of aas, structurally different attending to their R-side chain and with expected distinctive behaviour on aggregation mechanisms, which are also discussed. All proteinogenic amino acids induced AuNPs aggregation at low pH (2.5) cively of their R-side chain structure.The contamination of water sources by anthropogenic activities is a topic of growing interest in the scientific community. Therefore, robust analytical techniques for the determination and quantification of multiple substances are needed, which often require complex and time-consuming procedures. In this context, we describe a univariate calibration method to determine emerging multi-class contaminants in different water sources. The instrumental setup is composed of a lab-made glass electrochemical cell with three electrodes Pt counter, Ag/AgCl reference, and BDD working electrodes. With this system, we were able to simultaneously quantify tert-butylhydroquinone, acetaminophen, estrone, sulfamethoxazole, enrofloxacin, caffeine, and ibuprofen by differential pulse voltammetry. Only two calibration solutions are required for the Single-shot Dilution Differential Pulse Voltammetric Calibration (SSD-DP-VC) method described here, which can significantly improve sample throughput. Two robust univariate calibration strategies were also applied and compared with SSD-DP-VC. The new method is simple, fast, and comparable with traditional calibration methods, showing similar precision and accuracy for all determinations evaluated.
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